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The slope of fetal heart rate deceleration is predictive of fetal condition during repeated umbilical cord compression in sheep
The slope of fetal heart rate deceleration is predictive of fetal condition during repeated umbilical cord compression in sheep Kozo Akagi, MD," Kunihiro Okamura, MD," Chikara Endo, MD," Junya Saito, MD,a Shingo Tanigawara, MD,a Yoshiyuki Shintaku, MD," Takanori Watanabe, MD," Akira Sato, MD,' and Akira Yajima, MD•
Sendai, japan The relationship between components of fetal heart rate deceleration and fetal arterial blood gas values or plasma catecholamine concentrations was investigated by repeated complete umbilical cord compression in chronically instrumented fetal lamb. Fetal arterial pH and bicarbonate levels decreased, while plasma norepinephrine and epinephrine concentrations increased more than tenfold. The slope of the descending limb of the fetal heart rate deceleration curve decreased and correlated strongly with fetal arterial pH, bicarbonate, and logarithmic plasma norepinephrine and epinephrine concentrations. Fetal arterial pH and bicarbonate levels were significantly lower in the group with lower fetal heart rate deceleration slope, and a greater plasma catecholamine concentration in this group suggested a redistribution of blood flow to vital organs. Therefore, during repeated umbilical cord compression, the fetal acid-base and hormonal state was predicted by the fetal heart rate deceleration slope. This relationship may be applicable to human fetuses in the diagnosis of fetal distress caused by umbilical cord compression during labor. (AM J Ossrer GYNECOL 1988;159:516-22.)
Key words: Slope of fetal heart rate deceleration, sheep, catecholamines, umbilical cord compression
Fetal heart rate monitoring is now accepted as the most reliable method for assessing the fetal state. Among the various patterns that appear in fetal heart rate monitoring, variable deceleration is frequently observed during labor and is believed to be caused usually, if not always, by umbilical cord compression. Studies of the relationship between the fetal state and severity of variable deceleration (depth and duration) in human fetuses have produced variable results. 1• 2 Goodlin' stated that an abruptly reacting bradycardia was characteristic of a benign fetal state, whereas a briefly reacting bradycardia was characteristic of a worrisome fetal state. Myers et a!! analyzed the components oflate deceleration in fetal monkeys by occluding the aorta of the acutely anesthesized mother. However, no quantitative analysis of the components of variable deceleration has yet been performed in chronically instrumented animal fetuses. In the present study, we repeatedly compressed the umbilical cord of chronically instrumented lamb fetuses to simulate the gradual acidemic progress of delivery.
From the Department of Obstetrics and Gynecology, Tohoku University School of Medicine, • and Department of Obstetrics and Gynecology, Fukushima Medical College.h Received for publication June 26, 1987; revised December 29, 1987; accepted March 17, 1988. Reprint requests: Kozo Akagi, MD, Department of Obstetrics and Gynecology, Tohoku University School of Medicine, 1-1 Seiryomachi, Sendai, Miyagi Pre[, japan 980.
516
The relationship between deceleration components (depth and slope of the descending limb of the curve) and fetal arterial blood gas values or plasma catecholamine concentrations were investigated during this repeated cord compression.
Material and methods Four mixed-breed ewes of known gestational age (term about 150 days) were used, including one twin and three singleton pregnancies. Although the surgical procedure and postoperative treatment have been reported in detail,' we will briefly explain the procedure, including some points for which a slightly different approach was adopted. Gestational age of the lamb fetuses ranged between 110 and 123 days (mean 115.8 days). After the animals fasted for at least 24 hours, a midline abdominal incision was performed with the ewes under general anesthesia (nitrous oxide and halothane) with tracheal intubation (three ewes) or epidural anesthesia (one ewe). After exteriorization of the fetus, polyvinyl catheters (outer diameter 2.0 mm, inner diameter 1.2 mm) were inserted aseptically into the fetal carotid artery,jugular vein, and trachea (two ewes) with the use of local anesthesia. Tripolar cardioelectrodes were applied to the fetal chest wall. A vascular occluder with an inflatable balloon (OC-16, In Vivo Metric Inc., Healdsburg, Calif.) was placed around the umbilical cord near the fetal abdomen. After surgical procedures on the fetus had been completed, the fetus was re-
Slope of FHA deceleration in sheep
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Fig. 1. Components of fetal heart rate (FHR) deceleration and mean fetal arterial blood pressure (FABP) change during deceleration. !UP, Intrauterine pressure.
turned to the uterus and a polyvinyl catheter was inserted into the amniotic cavity. The catheters and cables were led directly out from the incision wound. Maternal femoral vessels were also cannulated with polyvinyl catheters. The ewe's activity, food and water intakes, and urine and stool outputs were assessed daily. The arterial catheter was infused continuously with heparin solution (0.1 IU/ml) to prevent coagulation. Antibiotics (mainly aminobenzyl penicillin) were administered into the maternal vein, amniotic cavity, and fetal vein daily during the postoperative period. The repeated, complete umbilical cord compression experiments were performed after the seventh postoperative day. The cord was compressed by inserting sterile saline solution into the balloon of the occluder for 40 seconds, followed by a period of 80 seconds with the occluder released. We performed this combination 15 times, and followed it with 60 seconds of compression and 60 seconds of release for 30 repetitions. The total duration of each experiment was about 90 minutes. Umbilical arterial flow was completely occluded within 3 to 4 seconds after the beginning of saline solution insertion, as confirmed by measurement of the umbilical arterial flow by an ultrasonic transit-time flowmeter 6 (Tl01 Transonic Systems Inc., Ithaca, N.Y.). Fetal arterial, tracheal, and intrauterine pressures were measured with pressure transducers (P23ID Gould Inc., Oxnard, Calif.; 4-327-I Bell Howell Inc. , Pasadena, Calif.). Fetal arterial blood pressure was corrected for intrauterine pressure. Fetal heart rate was monitored with a cardiotachometer triggered by the cardioelectric signal. All pressures, fetal heart rate, and a fetal electrocardiogram were recorded continuously on a pen recorder (Recti-Horiz 8K NEC San-ei Instru-
ments Co. Ltd., Tokyo, Japan) and data recorder (A49 Sony Magnescale Inc., Tokyo, Japan). Fetal arterial blood samples of 0.6 to 0.8 ml were drawn before the experiments and immediately after the end of every fifth cord compression. Blood gases were analyzed on an AVL 940 System (AVL AG, Schaffhausen, Switzerland) with temperature correction to 39° C. Actual bicarbonate was calculated in this system. After blood gas analyses, blood samples were centrifuged under cold conditions and separated plasma was stored frozen at -80° C until assayed. Plasma norepinephrine and epinephrine were measured in 50 fLl plasma samples by means of the singleisotope radioenzymatic assay as modified by Peuler and Johnson. 7 The sensitivity was 40 pg/ml for norepinephrine and 28 pg/ml for epinephrine. The assay was linear for values up to 20,000 pg/ml, with a slight decrease in linearity from 20,000 to 60,000 pg/ml. The within-run coefficient of variation did not exceed 14%. Reproducibility was monitored by inclusion of a plasma pool (norepinephrine, 357 ± 27 pg/ml; epinephrine, 28 ± 7 pg/ml, mean ± SD). Samples showing hemolysis were excluded from the assay. The components of deceleration and fetal arterial blood pressure during deceleration were determined from polygraph recordings (Fig. 1). Fetal heart rate baseline was determined as the fetal heart rate before · the start of deceleration. The slope of the descending limb of fetal heart rate deceleration (in beats per minute squared) was taken as the slope of the line linking two points (baseline - 0.2 times the depth of the deceleration, and baseline - 0.8 times this depth) on the descending limb of the deceleration curve. Fluctuations in fetal heart rate within 5 seconds were disregarded.
518
Akagi et al.
August 1988 Am J Obstet Gynecol
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Fig. 3. Mean ± SE change in fetal heart rate (FHR) slope (left), baseline and depth of fetal heart rate deceleration (middle), and plasma norepinephrine (NE) and epinephrine (E) concentrations (right).
The depth of fetal heart rate deceleration was the difference between baseline and the nadir. The fetal arterial blood pressure rise was the sudden rise in mean fetal arterial blood pressure at the beginning of cord compression. The fetal arterial blood pressure slope was the rate of decrease of mean arterial blood pressure during the period of fetal heart rate deceleration (if blood pressure increases, the value is negative). Depth of the dip in fetal arterial blood pressure was the difference in mean fetal arterial blood pressures between the predeceleration value and at the nadir of deceleration. We took as data the mean value of three sets of decelerations before, and two sets of decelerations after, the corresponding blood sampling. In analyzing the data, the mean, standard deviation,
and standard error were calculated. Student's t test was used to calculate the statistical significance. Correlations of fetal heart rate components with other data were derived by linear regression. Results
Six experiments were performed in four fetuses between 119 and 134 days of gestation (mean 126.0 days). Mean ( ± SE) fetal arterial blood gas values and plasma catecholamine concentrations before the experiments were as follows: pH, 7.293 ± 0.016, carbon dioxide partial pressure, 35.6 ± 2.7 mm Hg; oxygen partial pressure, 30.4 ± 1.9 mm Hg; bicarbonate, 17.7 ± 1.0 mEq/L; plasma norepinephrine, 800 ± 170 pg/ml; and plasma epinephrine, 230 ± 50 pg/ml. Fetal heart rate was 168 ± 6 beats/min and mean fetal arterial
Slope of FHA deceleration in sheep
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Table I. Correlation coefficients of fetal heart rate deceleration slope and depth of deceleration versus fetal arterial blood gas values and plasma catecholamine concentrations Fetal arterial measurement
pH Bicarbonate Log plasma norepinephrine Log plasma epinephrine Pco2 Po2
FHR slope
Depth ofFHR deceleration
0.581 * 0.506* -0.668*
-0.337t -0.033 -0.085
-0.608*
0.252
-0.249 -0.194
0.322 0.103
FHR, Fetal heart rate; Pco2 , partial carbon dioxide pressure; Po2 , partial oxygen pressure. *p < 0.001. tp < 0.01.
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blood pressure was 45 ± 3 mm Hg. Mean maternal arterial blood gas values and plasma catecholamine concentrations before the experiments were as follows: pH, 7.436 ± 0.031; carbon dioxide partial pressure, 31.3 ± 1.0 mm Hg, oxygen partial pressure, 146.5 ± 8.6 mm Hg; bicarbonate, 20.2 ± 1.1 mEq/L; norepinephrine, 320 ± 180 pg/ml; and epinephrine, 50 ± 20 pg/ml. Fetal pH decreased continuously except for the period between 10 and 30 minutes. The value before the experiment, 7.293, had dropped to 6.927 by the end of the experiments. Bicarbonate concentration also decreased gradually, from 17.7 to 9.1 mEq/L (Fig. 2, left). Carbon dioxide partial pressure remained low until the 40-minute point, then rose to a plateau. Oxygen partial pressure did not change much during the experiment (Fig. 2, right). The fetal heart rate slope dropped exponentially (Fig. 3, left), whereas the depth of the fetal heart rate deceleration increased only slightly during the experiment. Fetal heart rate baseline increased until the 50-minute point, then gradually decreased (Fig. 3, middle). The logarithmic plasma norepinephrine level increased until the 40-minute point and almost reached a plateau, whereas plasma epinephrine levels remained at the resting level until the 30-minute point and remained at a plateau thereafter (Fig. 3, right). Graded (mainly metabolic) acidemia developed, as shown in Fig. 2. As the value of carbon dioxide partial pressure was low until the 40-minute point and high thereafter, accumulation of carbon dioxide was considerably greater during 60-second compression than during 40second compression. The sudden increase in mean fetal arterial blood pressure immediately after the start of cord compression was maintained at a level of at least 12 mm Hg throughout the experimental period (Fig. 4). When the fetus was not acidemic, this increase in blood pressure continued during the compression period. However, as
0
30
60
Time(min)
90
Fig. 4. Mean ± SE change in fetal arterial blood pressure (FABP) rise, slope, and depth of the dip in values.
non-acidemic
acidemic
FHR
FABP
epinephrine
tt
peripheral resistance
tt
nor-
cardiac output Fig. 5. Diagram of nonacidemic and acidemic decelerations. FHR, Fetal heart rate; FABP, fetal arterial blood pressure.
the fetus became acidemic, fetal arterial blood pressure gradually dropped during the compression period, resulting in a level below the precompression value at the end of compression. As shown in Fig. 4, fetal arterial blood pressure slope and depth of the dip in fetal arterial blood pressure remained below the zero level until the 30-minute point, and increased at first steeply and then gradually thereafter.
520 Akagi et al.
August 1988 Am J Obstet Gynecol
Table II. Classification of fetal heart rate slope into two groups FHR slope (beatslmin 2) Fetal arterial measurement
pH Bicarbonate (mEq/L) Plasma norepinephrine (pg/ml) Plasma epinephrine (pg/ml) Blood pressure slope (mm Hg/min) Depth of dip in blood pressure (mm Hg)
<180 (mean, 126 ± 36)
p value
7.236 ± 0.052 15.4 ± 3.9 2100 ± 1800
7.034 ± 0.115 12.2 ± 3.4 13800 ± 13200
<0.001 <0.01 <0.01
500 ± 140
5700 ± 5100
<0.001
-0.6 ± 15.7
27.5 ± 12.7
<0.001
-0.1 ± 7.3
13.7 ± 10.0
<0.001
""180 (mean, 270 ± 96)
I
Data are the mean ± SD.
Calculated correlation coefficients for fetal heart rate components versus blood gas values and plasma catecholamine concentrations are listed in Table I. Strong positive correlations for fetal heart rate slope versus fetal arterial pH (r = 0.581, p < 0.00 I) .and bicarbonate concentration (r = 0.506, p < O.OOI) were observed. Strong negative correlations for fetal heart rate slope versus logarithmic plasma norepinephrine (r = 0.668, p < O.OOI) and epinephrine (r = -0.608, p < O.OOI) levels were also observed. Only a weak, negative correlation was observed for depth of fetal heart rate deceleration versus fetal arterial pH (r = -0.337, p < 0.01 ). No correlations for which the probability was I80 or <180 beats/min! As shown in Table II, significant differences were observed between the two groups for fetal arterial pH, bicarbonate, plasma norepinephrine, and plasma epinephrine concentrations, fetal arterial blood pressure slope, and the depth of the dip in fetal arterial blood pressure. Comment
The chronically instrumented pregnant sheep has been widely used for fetal cardiovascular and endocrinologic investigation during fetal hypoxia. Three methods have been used to induce the fetal hypoxia. The first method is to allow the ewe to breathe a low-oxygen gas mixture, and the second is to reduce uteroplacental perfusion by occluding the maternal hypogastric artery 8 or distal aorta. The third method involves compression of the umbilical cord to various degrees,
as reported by Itskovitz et a!." Compression of the umbilical cord is thought to be the main reason for variable deceleration and a common cause of fetal hypoxia. Because variable deceleration usually occurs periodically during labor and acidemia gradually progresses in human fetuses, 10 repeated umbilical cord compression is the most appropriate method for simulating fetal hypoxia. 'It has been demonstrated in instrumented lamb fetuses that during hypoxia there is a redistribution of fetal cardiac output. This redistribution favors the perfusion of vital organs such as the brain, heart, and adrenal medulla, resulting in decreased perfusion of less vital organs.u· 12 Dawes et a!. 13 measured the hind limb vascular resistance of chronically instrumented lamb fetuses and found that norepinephrine infusion induced a vasoconstrictive response similar to that occurring during the period of hypoxia produced by umbilical cord compression; the response was still observed after resection of the femoral nerve. Lorijn and Longo 14 infused norepinephrine into chronically catheterized lamb fetuses and demonstrated that, at an infusion rate of I ~J..g/min/kg, the mean ( ± SD) fetal norepinephrine concentration was 4500 ± 800 pg/ml. Coronary and umbilical blood flows were increased, whereas flows to the upper and lower parts of the body and the gastrointestinal tract were decreased. Cardiac output remained essentially constant. In our experiment, logarithmic norepinephrine levels increased linearly up to the 40- and 50-minute point, and thereafter reached a plateau at> IO,OOO pg/ml, which was a sufficient concentration to induce redistribution. After norepinephrine had reached this plateau, redistribution would not have progressed further, the hypoxia of the vital organs might have occurred. It is not infrequent during human delivery for the umbilical arterial norepinephrine concentration to exceed 10,000 pg/ml. As a model to simulate fetal distress during labor, an intensity of stress in our experiment that produced a level of norepinephrine> 10,000 pg/ml was considered appropriate.
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The difference between the norepinephrine and epinephrine responses might be attributable to differences in the threshold response to hypoxic stimulation, as suggested by Comline et a!. 15 Because the fetal heart rate deceleration slope was strongly correlated with plasma catecholamine levels, especially that of norepinephrine, we were able to indirectly estimate the presence of redistribution of fetal cardiac output. We tried to divide this fetal heart rate slope value into two classes. Table II shows that the plasma levels of norepinephrine and epinephrine reached a plateau when the fetal heart rate slope was <180 beats/min! At this point, the fetus could no longer secrete catecholamines, and thus could not further redistribute the cardiac output. Plasma norepinephrine and epinephrine concentrations were signi~cantly smaller when the fetal heart rate slope was > 180 beats/min 2 , and thus the fetus was able to respond to the hypoxic stress by producing more catecholamines and further redistributing the cardiac output to vital organs. In the experiment involving complete cord compression, the first fetal heart rate response occurring within 8 to 10 seconds after the beginning of cord com pression was thought to be generated by baroreceptors. 16 The initial cardiovascular response to cord compression was a sudden rise of about 15 mm Hg in fetal arterial blood pressure, followed by a steep decrease in fetal heart rate when the fetus was not acidemic. As shown in Fig. 5, fetal arterial blood pressure remained elevated and fetal heart rate remained low during compression. Although cardiac output might have been depressed in parallel with the fetal heart rate decrease, fetal arterial blood pressure was elevated by the increase of peripheral resistance that was maintained during compression. The fetal arterial blood pressure rise did not decrease below 12 mm Hg (Fig. 4), even when the fetus became acidemic. Therefore, fetal heart rate would not have responded to the stimulated baroreceptors in the acidemic state. Fetal heart rate and fetal arterial blood pressure gradually decreased during the period of compression, and fetal arterial blood pressure decreased to below the precompression level at the end of the compression. The change in peripheral resistance during the compression period was estimated to be small; a gradual decrease in fetal arterial blood pressure indicated a gradual decrease in cardiac output. Cardiac output at the end of compression was estimated to be lower than that in the nonacidemic state, because the fetal arterial blood pressure level was much lower and peripheral resistance was higher due to elevated levels of norepinephrine. Because fetal heart rate was essentially the same as that in a nonacidemic state, cardiac stroke volume was decreased at the end of compression in the acidemic state. Martin et aJ.B performed intermittent total occlusion
Slope of FHA deceleration in sheep
521
of the maternal common iliac artery and produced gradual fetal acidemia and experimental late deceleration. They reported that fetal hypertension occurred with deceleration and that this deceleration was blocked by atropine administration if acidemia was not present. Fetal hypertension did not occur, and the deceleration could not be blocked by atropine administration during acidemia. Although their way of inducing deceleration was different from ours, the relationship between fetal arterial blood pressure status during deceleration and fetal acidemia was the same as the relationship in our data. We conclude that by classifying the fetal heart rate deceleration slope into two groups separated at the value of 180 beats/min 2 , assessment of the fetal state was possible. In other words, if the slope value was > 180 beats/min 2 , the fetus was not acidemic, catecholamine levels were not so high, and a marked decrease in cardiac output during compression was unlikely because fetal arterial blood pressure was not decreased during the period of cord compression. Conversely, if the fetal heart rate slope was < 180 beats/min 2 , the fetus was acidemic, catecholamine levels were high, and a marked decrease in cardiac output was very likely, because the fetal arterial blood pressure slope was positive and a dip in fetal arterial blood pressure was present. In this model, if deceleration was caused by repeated abrupt total cord compression, the fetal heart rate deceleration slope was a good indicator for assessing fetal acid-base and humoral status. Whether this assumption applies to human labor, however, requires further investigation. REFERENCES 1. Kubli FW, Hon EH, Khazin AF, Takemura H. Observation on heart rate and pH in the human fetus during labor. AMj 0BSTET GYNECOL 1969;104:1190. 2. Krebs HB, Petres RE, Dunn LJ,Jordaan HVF, Segreti A. Intrapartum fetal heart rate monitoring. AM J OBSTET GYNECOL 1979; 133:762. 3. Goodlin RC. Fetal cardiovascular responses to distress. Obstet Gynecol 1977;49:371. 4. Myers RE, Mueller-Heubach E, Adamsons K. Predictability of the state of fetal oxygenation from a quantitative analysis of the components of late deceleration. AM J OBSTET GYNECOL 1973;115:1083. 5. Sato A, Endo C, Kyozuka M, et al. A method for making chronic fetal preparation in the lamb; result of 4 years' experiences. TohokuJ Exp Med 1985;147:157. 6. Akagi K, Endo C, Saito J, et al. Ultrasonic transit-time measurement of blood flow in the animal chronic preparation model [English abstract]. Jap J Med Ultrason 1987;14:104. 7. Peuler JD, Johnson GA. Simultaneous single isotope radioenzymatic assay of plasma norepinephrine, epinephrine and dopamine. Life Sci 1977;21:625. 8. Martin CBJr, de HaanJ, van der Wildt B,Jongsma HW, Dieleman A, Arts THM. Mechanism of late decelerations in the fetal heart rate. Eur J Obstet Gynecol Reprod Bioi 1979;9:361. 9. Itskovitz J, LaGamma EF, Rudolph AM. Heart rate and blood pressure responses to umbilical cord compression in fetal lambs with special reference to the mechanism of
Akagi et al.
10. II.
12. 13.
variable deceleration. AM J 0BSTET GYNECOL 1983;147: 451. Modanlou H, Yeh SY, Hon EH, Forsythe A. Fetal and neonatal biochemistry and Apgar scores. AM J OBSTET GYNECOL 1973;117:942. Sheldon RE, Peeters LLH, Jones MD Jr, Makowski EL, Meschia G. Redistribution of cardiac output and oxygen delivery in the hypoxemic fetal lamb. AM J OBSTET GvNECOL 1979;135:1071. Cohn HE, Sacks EJ, Heymann MA, Rudolph AM. Cardiovascular responses to hypoxemia and acidemia in fetal lambs. AMJ 0BSTET GYNECOL 1974;120:817. Dawes GS, Lewis BV, MilliganJE, Roach MR, Talner NS.
August 1988 Am J Obstet Gynecol
Vasomotor responses in the hind limb of foetal and newborn lambs to asphyxia and aortic chemoreceptor stimulation. J Physiol 1968; 195:55. 14. Lorijn RHW, Longo LD. Norepinephrine elevation in the fetal lamb: oxygen consumption and cardiac output. Am J Physiol l980;239:Rll5. 15. Comline RS, Silver IA, Silver M. Factors responsible for the stimulation of the adrenal medulla during asphyxia in the foetal lamb. J Physiol 1965; 178:211. 16. Kiinzel W. Fetal heart rate alterations in partial and total cord occlusion. In: Kiinzel W, ed. Fetal heart rate monitoring. Berlin: Springer-Verlag, 1985.
Vitamin B 12 R-binder localization in the human uterus: An immunohistochemical study Young Chi Kim, MD, Hiroyuki Kudo, MD, Katsuhiko Ogawa, MD, Gakuji Ohshio, MD, Thi Thi Aye, MB, BS, Yasuaki Nakashima, MD, Kenji Takakura, MD, Shingo Fujii, MD, Masami Inada, MD, and Hirohiko Yamabe, MD Kyoto, japan The localization of vitamin 8, 2 A-binder in the uterus was studied by use of an immunoperoxidase technique. Positive staining by anti-A-binder antiserum was observed in the columnar epithelium of the endocervix (18/18 cases) and in the surface epithelium of the endometrium (8/21 cases). Staining was usually seen in the apical portion of the epithelium; cytoplasmic staining in the endocervical columnar epithelium was intense. The secretory products in the endocervical glands showed positive staining. The endometrial glandular epithelium did not stain (0/24 cases). Metaplastic squamous epithelium of the endocervix showed positive staining (3/18 cases). The native squamous epithelium as well as the stromal components of the cervix, endometrium, and myometrium were negative for A-binder. This study shows that A-binder is localized in the uterus, especially in the endocervical glands. The A-binder in the endocervix may have antimicrobial activity in the uterus as in other organs, such as the intestines and mammary glands. (AM J 0BSTET GYNECOL 1988;159:522-6.)
Key words: Vitamin B 12 , R-binder, uterus, immunohistochemistry Vitamin B 12 R-binder, a specific binding protein for vitamin B 12 , is ubiquitous in body fluids, granulocytes, and plasma. 1· 5 It is widely distributed in the glandular epithelium of various human tissues such as the digestive tract, bronchial glands, renal proximal tubules, sweat glands, mammary glands, and prostate gland. 6 • 7 R-binder is speculated to have an antimicrobial function in the intestine and mammary glands. 2 · 8 · 9 Although the uterus is exposed to commensal microorganisms, the precise localization of R-binder in the human uterus has not been reported. Therefore,
From the Laboratory of Anatomic Pathology and Central Clinical Laboratory, Departments of Pathology, Geriatric Medicine, and Obstetrics and Gynecology, Faculty of Medicine, Kyoto University. Received for publication july 14, 1987; revised February 24, 1988; accepted March 5, 1988. Reprint requests: Young Chi Kim, MD, Laboratory of Anatomic Pathology, Kyoto University Hospital, 54 Shogoin-Kawahara-cho, Sakyo-ku, Kyoto 606, japan.
522
we used an immunoperoxidase technique to examine the localization of R-binder in the normal human uterus. Material and methods Cases. Twenty~four surgically removed uterine bodies and 18 cervices were obtained from leiomyomabearing patients between 30 and 53 years old (average 43 years). The specimens were fixed in 10% formalin and embedded in paraffin. Freshly cut 4 1-Lm thick sections were stained with hematoxylin-eosin; they were examined and confirmed to have normal endometrial and endocervical tissues without inflammatory changes. Endometrial date was determined in 24 endometrial tissues according to the criteria of Noyes et al. 10 Twelve samples were from the proliferative phase and 12 were from the secretory phase. These paraffin-embedded sections were used for the study of immunohistochemical localization of the R-binder.
Sendai, japan The relationship between components of fetal heart rate deceleration and fetal arterial blood gas values or plasma catecholamine concentrations was investigated by repeated complete umbilical cord compression in chronically instrumented fetal lamb. Fetal arterial pH and bicarbonate levels decreased, while plasma norepinephrine and epinephrine concentrations increased more than tenfold. The slope of the descending limb of the fetal heart rate deceleration curve decreased and correlated strongly with fetal arterial pH, bicarbonate, and logarithmic plasma norepinephrine and epinephrine concentrations. Fetal arterial pH and bicarbonate levels were significantly lower in the group with lower fetal heart rate deceleration slope, and a greater plasma catecholamine concentration in this group suggested a redistribution of blood flow to vital organs. Therefore, during repeated umbilical cord compression, the fetal acid-base and hormonal state was predicted by the fetal heart rate deceleration slope. This relationship may be applicable to human fetuses in the diagnosis of fetal distress caused by umbilical cord compression during labor. (AM J Ossrer GYNECOL 1988;159:516-22.)
Key words: Slope of fetal heart rate deceleration, sheep, catecholamines, umbilical cord compression
Fetal heart rate monitoring is now accepted as the most reliable method for assessing the fetal state. Among the various patterns that appear in fetal heart rate monitoring, variable deceleration is frequently observed during labor and is believed to be caused usually, if not always, by umbilical cord compression. Studies of the relationship between the fetal state and severity of variable deceleration (depth and duration) in human fetuses have produced variable results. 1• 2 Goodlin' stated that an abruptly reacting bradycardia was characteristic of a benign fetal state, whereas a briefly reacting bradycardia was characteristic of a worrisome fetal state. Myers et a!! analyzed the components oflate deceleration in fetal monkeys by occluding the aorta of the acutely anesthesized mother. However, no quantitative analysis of the components of variable deceleration has yet been performed in chronically instrumented animal fetuses. In the present study, we repeatedly compressed the umbilical cord of chronically instrumented lamb fetuses to simulate the gradual acidemic progress of delivery.
From the Department of Obstetrics and Gynecology, Tohoku University School of Medicine, • and Department of Obstetrics and Gynecology, Fukushima Medical College.h Received for publication June 26, 1987; revised December 29, 1987; accepted March 17, 1988. Reprint requests: Kozo Akagi, MD, Department of Obstetrics and Gynecology, Tohoku University School of Medicine, 1-1 Seiryomachi, Sendai, Miyagi Pre[, japan 980.
516
The relationship between deceleration components (depth and slope of the descending limb of the curve) and fetal arterial blood gas values or plasma catecholamine concentrations were investigated during this repeated cord compression.
Material and methods Four mixed-breed ewes of known gestational age (term about 150 days) were used, including one twin and three singleton pregnancies. Although the surgical procedure and postoperative treatment have been reported in detail,' we will briefly explain the procedure, including some points for which a slightly different approach was adopted. Gestational age of the lamb fetuses ranged between 110 and 123 days (mean 115.8 days). After the animals fasted for at least 24 hours, a midline abdominal incision was performed with the ewes under general anesthesia (nitrous oxide and halothane) with tracheal intubation (three ewes) or epidural anesthesia (one ewe). After exteriorization of the fetus, polyvinyl catheters (outer diameter 2.0 mm, inner diameter 1.2 mm) were inserted aseptically into the fetal carotid artery,jugular vein, and trachea (two ewes) with the use of local anesthesia. Tripolar cardioelectrodes were applied to the fetal chest wall. A vascular occluder with an inflatable balloon (OC-16, In Vivo Metric Inc., Healdsburg, Calif.) was placed around the umbilical cord near the fetal abdomen. After surgical procedures on the fetus had been completed, the fetus was re-
Slope of FHA deceleration in sheep
Volume 159 Number 2
517
Fig. 1. Components of fetal heart rate (FHR) deceleration and mean fetal arterial blood pressure (FABP) change during deceleration. !UP, Intrauterine pressure.
turned to the uterus and a polyvinyl catheter was inserted into the amniotic cavity. The catheters and cables were led directly out from the incision wound. Maternal femoral vessels were also cannulated with polyvinyl catheters. The ewe's activity, food and water intakes, and urine and stool outputs were assessed daily. The arterial catheter was infused continuously with heparin solution (0.1 IU/ml) to prevent coagulation. Antibiotics (mainly aminobenzyl penicillin) were administered into the maternal vein, amniotic cavity, and fetal vein daily during the postoperative period. The repeated, complete umbilical cord compression experiments were performed after the seventh postoperative day. The cord was compressed by inserting sterile saline solution into the balloon of the occluder for 40 seconds, followed by a period of 80 seconds with the occluder released. We performed this combination 15 times, and followed it with 60 seconds of compression and 60 seconds of release for 30 repetitions. The total duration of each experiment was about 90 minutes. Umbilical arterial flow was completely occluded within 3 to 4 seconds after the beginning of saline solution insertion, as confirmed by measurement of the umbilical arterial flow by an ultrasonic transit-time flowmeter 6 (Tl01 Transonic Systems Inc., Ithaca, N.Y.). Fetal arterial, tracheal, and intrauterine pressures were measured with pressure transducers (P23ID Gould Inc., Oxnard, Calif.; 4-327-I Bell Howell Inc. , Pasadena, Calif.). Fetal arterial blood pressure was corrected for intrauterine pressure. Fetal heart rate was monitored with a cardiotachometer triggered by the cardioelectric signal. All pressures, fetal heart rate, and a fetal electrocardiogram were recorded continuously on a pen recorder (Recti-Horiz 8K NEC San-ei Instru-
ments Co. Ltd., Tokyo, Japan) and data recorder (A49 Sony Magnescale Inc., Tokyo, Japan). Fetal arterial blood samples of 0.6 to 0.8 ml were drawn before the experiments and immediately after the end of every fifth cord compression. Blood gases were analyzed on an AVL 940 System (AVL AG, Schaffhausen, Switzerland) with temperature correction to 39° C. Actual bicarbonate was calculated in this system. After blood gas analyses, blood samples were centrifuged under cold conditions and separated plasma was stored frozen at -80° C until assayed. Plasma norepinephrine and epinephrine were measured in 50 fLl plasma samples by means of the singleisotope radioenzymatic assay as modified by Peuler and Johnson. 7 The sensitivity was 40 pg/ml for norepinephrine and 28 pg/ml for epinephrine. The assay was linear for values up to 20,000 pg/ml, with a slight decrease in linearity from 20,000 to 60,000 pg/ml. The within-run coefficient of variation did not exceed 14%. Reproducibility was monitored by inclusion of a plasma pool (norepinephrine, 357 ± 27 pg/ml; epinephrine, 28 ± 7 pg/ml, mean ± SD). Samples showing hemolysis were excluded from the assay. The components of deceleration and fetal arterial blood pressure during deceleration were determined from polygraph recordings (Fig. 1). Fetal heart rate baseline was determined as the fetal heart rate before · the start of deceleration. The slope of the descending limb of fetal heart rate deceleration (in beats per minute squared) was taken as the slope of the line linking two points (baseline - 0.2 times the depth of the deceleration, and baseline - 0.8 times this depth) on the descending limb of the deceleration curve. Fluctuations in fetal heart rate within 5 seconds were disregarded.
518
Akagi et al.
August 1988 Am J Obstet Gynecol
7.30
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0 30
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Fig. 3. Mean ± SE change in fetal heart rate (FHR) slope (left), baseline and depth of fetal heart rate deceleration (middle), and plasma norepinephrine (NE) and epinephrine (E) concentrations (right).
The depth of fetal heart rate deceleration was the difference between baseline and the nadir. The fetal arterial blood pressure rise was the sudden rise in mean fetal arterial blood pressure at the beginning of cord compression. The fetal arterial blood pressure slope was the rate of decrease of mean arterial blood pressure during the period of fetal heart rate deceleration (if blood pressure increases, the value is negative). Depth of the dip in fetal arterial blood pressure was the difference in mean fetal arterial blood pressures between the predeceleration value and at the nadir of deceleration. We took as data the mean value of three sets of decelerations before, and two sets of decelerations after, the corresponding blood sampling. In analyzing the data, the mean, standard deviation,
and standard error were calculated. Student's t test was used to calculate the statistical significance. Correlations of fetal heart rate components with other data were derived by linear regression. Results
Six experiments were performed in four fetuses between 119 and 134 days of gestation (mean 126.0 days). Mean ( ± SE) fetal arterial blood gas values and plasma catecholamine concentrations before the experiments were as follows: pH, 7.293 ± 0.016, carbon dioxide partial pressure, 35.6 ± 2.7 mm Hg; oxygen partial pressure, 30.4 ± 1.9 mm Hg; bicarbonate, 17.7 ± 1.0 mEq/L; plasma norepinephrine, 800 ± 170 pg/ml; and plasma epinephrine, 230 ± 50 pg/ml. Fetal heart rate was 168 ± 6 beats/min and mean fetal arterial
Slope of FHA deceleration in sheep
Volume 159 Number 2
Table I. Correlation coefficients of fetal heart rate deceleration slope and depth of deceleration versus fetal arterial blood gas values and plasma catecholamine concentrations Fetal arterial measurement
pH Bicarbonate Log plasma norepinephrine Log plasma epinephrine Pco2 Po2
FHR slope
Depth ofFHR deceleration
0.581 * 0.506* -0.668*
-0.337t -0.033 -0.085
-0.608*
0.252
-0.249 -0.194
0.322 0.103
FHR, Fetal heart rate; Pco2 , partial carbon dioxide pressure; Po2 , partial oxygen pressure. *p < 0.001. tp < 0.01.
20[
519
FABP rise
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FABP 10
(mmHg)
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40 30
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blood pressure was 45 ± 3 mm Hg. Mean maternal arterial blood gas values and plasma catecholamine concentrations before the experiments were as follows: pH, 7.436 ± 0.031; carbon dioxide partial pressure, 31.3 ± 1.0 mm Hg, oxygen partial pressure, 146.5 ± 8.6 mm Hg; bicarbonate, 20.2 ± 1.1 mEq/L; norepinephrine, 320 ± 180 pg/ml; and epinephrine, 50 ± 20 pg/ml. Fetal pH decreased continuously except for the period between 10 and 30 minutes. The value before the experiment, 7.293, had dropped to 6.927 by the end of the experiments. Bicarbonate concentration also decreased gradually, from 17.7 to 9.1 mEq/L (Fig. 2, left). Carbon dioxide partial pressure remained low until the 40-minute point, then rose to a plateau. Oxygen partial pressure did not change much during the experiment (Fig. 2, right). The fetal heart rate slope dropped exponentially (Fig. 3, left), whereas the depth of the fetal heart rate deceleration increased only slightly during the experiment. Fetal heart rate baseline increased until the 50-minute point, then gradually decreased (Fig. 3, middle). The logarithmic plasma norepinephrine level increased until the 40-minute point and almost reached a plateau, whereas plasma epinephrine levels remained at the resting level until the 30-minute point and remained at a plateau thereafter (Fig. 3, right). Graded (mainly metabolic) acidemia developed, as shown in Fig. 2. As the value of carbon dioxide partial pressure was low until the 40-minute point and high thereafter, accumulation of carbon dioxide was considerably greater during 60-second compression than during 40second compression. The sudden increase in mean fetal arterial blood pressure immediately after the start of cord compression was maintained at a level of at least 12 mm Hg throughout the experimental period (Fig. 4). When the fetus was not acidemic, this increase in blood pressure continued during the compression period. However, as
0
30
60
Time(min)
90
Fig. 4. Mean ± SE change in fetal arterial blood pressure (FABP) rise, slope, and depth of the dip in values.
non-acidemic
acidemic
FHR
FABP
epinephrine
tt
peripheral resistance
tt
nor-
cardiac output Fig. 5. Diagram of nonacidemic and acidemic decelerations. FHR, Fetal heart rate; FABP, fetal arterial blood pressure.
the fetus became acidemic, fetal arterial blood pressure gradually dropped during the compression period, resulting in a level below the precompression value at the end of compression. As shown in Fig. 4, fetal arterial blood pressure slope and depth of the dip in fetal arterial blood pressure remained below the zero level until the 30-minute point, and increased at first steeply and then gradually thereafter.
520 Akagi et al.
August 1988 Am J Obstet Gynecol
Table II. Classification of fetal heart rate slope into two groups FHR slope (beatslmin 2) Fetal arterial measurement
pH Bicarbonate (mEq/L) Plasma norepinephrine (pg/ml) Plasma epinephrine (pg/ml) Blood pressure slope (mm Hg/min) Depth of dip in blood pressure (mm Hg)
<180 (mean, 126 ± 36)
p value
7.236 ± 0.052 15.4 ± 3.9 2100 ± 1800
7.034 ± 0.115 12.2 ± 3.4 13800 ± 13200
<0.001 <0.01 <0.01
500 ± 140
5700 ± 5100
<0.001
-0.6 ± 15.7
27.5 ± 12.7
<0.001
-0.1 ± 7.3
13.7 ± 10.0
<0.001
""180 (mean, 270 ± 96)
I
Data are the mean ± SD.
Calculated correlation coefficients for fetal heart rate components versus blood gas values and plasma catecholamine concentrations are listed in Table I. Strong positive correlations for fetal heart rate slope versus fetal arterial pH (r = 0.581, p < 0.00 I) .and bicarbonate concentration (r = 0.506, p < O.OOI) were observed. Strong negative correlations for fetal heart rate slope versus logarithmic plasma norepinephrine (r = 0.668, p < O.OOI) and epinephrine (r = -0.608, p < O.OOI) levels were also observed. Only a weak, negative correlation was observed for depth of fetal heart rate deceleration versus fetal arterial pH (r = -0.337, p < 0.01 ). No correlations for which the probability was
The chronically instrumented pregnant sheep has been widely used for fetal cardiovascular and endocrinologic investigation during fetal hypoxia. Three methods have been used to induce the fetal hypoxia. The first method is to allow the ewe to breathe a low-oxygen gas mixture, and the second is to reduce uteroplacental perfusion by occluding the maternal hypogastric artery 8 or distal aorta. The third method involves compression of the umbilical cord to various degrees,
as reported by Itskovitz et a!." Compression of the umbilical cord is thought to be the main reason for variable deceleration and a common cause of fetal hypoxia. Because variable deceleration usually occurs periodically during labor and acidemia gradually progresses in human fetuses, 10 repeated umbilical cord compression is the most appropriate method for simulating fetal hypoxia. 'It has been demonstrated in instrumented lamb fetuses that during hypoxia there is a redistribution of fetal cardiac output. This redistribution favors the perfusion of vital organs such as the brain, heart, and adrenal medulla, resulting in decreased perfusion of less vital organs.u· 12 Dawes et a!. 13 measured the hind limb vascular resistance of chronically instrumented lamb fetuses and found that norepinephrine infusion induced a vasoconstrictive response similar to that occurring during the period of hypoxia produced by umbilical cord compression; the response was still observed after resection of the femoral nerve. Lorijn and Longo 14 infused norepinephrine into chronically catheterized lamb fetuses and demonstrated that, at an infusion rate of I ~J..g/min/kg, the mean ( ± SD) fetal norepinephrine concentration was 4500 ± 800 pg/ml. Coronary and umbilical blood flows were increased, whereas flows to the upper and lower parts of the body and the gastrointestinal tract were decreased. Cardiac output remained essentially constant. In our experiment, logarithmic norepinephrine levels increased linearly up to the 40- and 50-minute point, and thereafter reached a plateau at> IO,OOO pg/ml, which was a sufficient concentration to induce redistribution. After norepinephrine had reached this plateau, redistribution would not have progressed further, the hypoxia of the vital organs might have occurred. It is not infrequent during human delivery for the umbilical arterial norepinephrine concentration to exceed 10,000 pg/ml. As a model to simulate fetal distress during labor, an intensity of stress in our experiment that produced a level of norepinephrine> 10,000 pg/ml was considered appropriate.
Volume 159 Number 2
The difference between the norepinephrine and epinephrine responses might be attributable to differences in the threshold response to hypoxic stimulation, as suggested by Comline et a!. 15 Because the fetal heart rate deceleration slope was strongly correlated with plasma catecholamine levels, especially that of norepinephrine, we were able to indirectly estimate the presence of redistribution of fetal cardiac output. We tried to divide this fetal heart rate slope value into two classes. Table II shows that the plasma levels of norepinephrine and epinephrine reached a plateau when the fetal heart rate slope was <180 beats/min! At this point, the fetus could no longer secrete catecholamines, and thus could not further redistribute the cardiac output. Plasma norepinephrine and epinephrine concentrations were signi~cantly smaller when the fetal heart rate slope was > 180 beats/min 2 , and thus the fetus was able to respond to the hypoxic stress by producing more catecholamines and further redistributing the cardiac output to vital organs. In the experiment involving complete cord compression, the first fetal heart rate response occurring within 8 to 10 seconds after the beginning of cord com pression was thought to be generated by baroreceptors. 16 The initial cardiovascular response to cord compression was a sudden rise of about 15 mm Hg in fetal arterial blood pressure, followed by a steep decrease in fetal heart rate when the fetus was not acidemic. As shown in Fig. 5, fetal arterial blood pressure remained elevated and fetal heart rate remained low during compression. Although cardiac output might have been depressed in parallel with the fetal heart rate decrease, fetal arterial blood pressure was elevated by the increase of peripheral resistance that was maintained during compression. The fetal arterial blood pressure rise did not decrease below 12 mm Hg (Fig. 4), even when the fetus became acidemic. Therefore, fetal heart rate would not have responded to the stimulated baroreceptors in the acidemic state. Fetal heart rate and fetal arterial blood pressure gradually decreased during the period of compression, and fetal arterial blood pressure decreased to below the precompression level at the end of the compression. The change in peripheral resistance during the compression period was estimated to be small; a gradual decrease in fetal arterial blood pressure indicated a gradual decrease in cardiac output. Cardiac output at the end of compression was estimated to be lower than that in the nonacidemic state, because the fetal arterial blood pressure level was much lower and peripheral resistance was higher due to elevated levels of norepinephrine. Because fetal heart rate was essentially the same as that in a nonacidemic state, cardiac stroke volume was decreased at the end of compression in the acidemic state. Martin et aJ.B performed intermittent total occlusion
Slope of FHA deceleration in sheep
521
of the maternal common iliac artery and produced gradual fetal acidemia and experimental late deceleration. They reported that fetal hypertension occurred with deceleration and that this deceleration was blocked by atropine administration if acidemia was not present. Fetal hypertension did not occur, and the deceleration could not be blocked by atropine administration during acidemia. Although their way of inducing deceleration was different from ours, the relationship between fetal arterial blood pressure status during deceleration and fetal acidemia was the same as the relationship in our data. We conclude that by classifying the fetal heart rate deceleration slope into two groups separated at the value of 180 beats/min 2 , assessment of the fetal state was possible. In other words, if the slope value was > 180 beats/min 2 , the fetus was not acidemic, catecholamine levels were not so high, and a marked decrease in cardiac output during compression was unlikely because fetal arterial blood pressure was not decreased during the period of cord compression. Conversely, if the fetal heart rate slope was < 180 beats/min 2 , the fetus was acidemic, catecholamine levels were high, and a marked decrease in cardiac output was very likely, because the fetal arterial blood pressure slope was positive and a dip in fetal arterial blood pressure was present. In this model, if deceleration was caused by repeated abrupt total cord compression, the fetal heart rate deceleration slope was a good indicator for assessing fetal acid-base and humoral status. Whether this assumption applies to human labor, however, requires further investigation. REFERENCES 1. Kubli FW, Hon EH, Khazin AF, Takemura H. Observation on heart rate and pH in the human fetus during labor. AMj 0BSTET GYNECOL 1969;104:1190. 2. Krebs HB, Petres RE, Dunn LJ,Jordaan HVF, Segreti A. Intrapartum fetal heart rate monitoring. AM J OBSTET GYNECOL 1979; 133:762. 3. Goodlin RC. Fetal cardiovascular responses to distress. Obstet Gynecol 1977;49:371. 4. Myers RE, Mueller-Heubach E, Adamsons K. Predictability of the state of fetal oxygenation from a quantitative analysis of the components of late deceleration. AM J OBSTET GYNECOL 1973;115:1083. 5. Sato A, Endo C, Kyozuka M, et al. A method for making chronic fetal preparation in the lamb; result of 4 years' experiences. TohokuJ Exp Med 1985;147:157. 6. Akagi K, Endo C, Saito J, et al. Ultrasonic transit-time measurement of blood flow in the animal chronic preparation model [English abstract]. Jap J Med Ultrason 1987;14:104. 7. Peuler JD, Johnson GA. Simultaneous single isotope radioenzymatic assay of plasma norepinephrine, epinephrine and dopamine. Life Sci 1977;21:625. 8. Martin CBJr, de HaanJ, van der Wildt B,Jongsma HW, Dieleman A, Arts THM. Mechanism of late decelerations in the fetal heart rate. Eur J Obstet Gynecol Reprod Bioi 1979;9:361. 9. Itskovitz J, LaGamma EF, Rudolph AM. Heart rate and blood pressure responses to umbilical cord compression in fetal lambs with special reference to the mechanism of
Akagi et al.
10. II.
12. 13.
variable deceleration. AM J 0BSTET GYNECOL 1983;147: 451. Modanlou H, Yeh SY, Hon EH, Forsythe A. Fetal and neonatal biochemistry and Apgar scores. AM J OBSTET GYNECOL 1973;117:942. Sheldon RE, Peeters LLH, Jones MD Jr, Makowski EL, Meschia G. Redistribution of cardiac output and oxygen delivery in the hypoxemic fetal lamb. AM J OBSTET GvNECOL 1979;135:1071. Cohn HE, Sacks EJ, Heymann MA, Rudolph AM. Cardiovascular responses to hypoxemia and acidemia in fetal lambs. AMJ 0BSTET GYNECOL 1974;120:817. Dawes GS, Lewis BV, MilliganJE, Roach MR, Talner NS.
August 1988 Am J Obstet Gynecol
Vasomotor responses in the hind limb of foetal and newborn lambs to asphyxia and aortic chemoreceptor stimulation. J Physiol 1968; 195:55. 14. Lorijn RHW, Longo LD. Norepinephrine elevation in the fetal lamb: oxygen consumption and cardiac output. Am J Physiol l980;239:Rll5. 15. Comline RS, Silver IA, Silver M. Factors responsible for the stimulation of the adrenal medulla during asphyxia in the foetal lamb. J Physiol 1965; 178:211. 16. Kiinzel W. Fetal heart rate alterations in partial and total cord occlusion. In: Kiinzel W, ed. Fetal heart rate monitoring. Berlin: Springer-Verlag, 1985.
Vitamin B 12 R-binder localization in the human uterus: An immunohistochemical study Young Chi Kim, MD, Hiroyuki Kudo, MD, Katsuhiko Ogawa, MD, Gakuji Ohshio, MD, Thi Thi Aye, MB, BS, Yasuaki Nakashima, MD, Kenji Takakura, MD, Shingo Fujii, MD, Masami Inada, MD, and Hirohiko Yamabe, MD Kyoto, japan The localization of vitamin 8, 2 A-binder in the uterus was studied by use of an immunoperoxidase technique. Positive staining by anti-A-binder antiserum was observed in the columnar epithelium of the endocervix (18/18 cases) and in the surface epithelium of the endometrium (8/21 cases). Staining was usually seen in the apical portion of the epithelium; cytoplasmic staining in the endocervical columnar epithelium was intense. The secretory products in the endocervical glands showed positive staining. The endometrial glandular epithelium did not stain (0/24 cases). Metaplastic squamous epithelium of the endocervix showed positive staining (3/18 cases). The native squamous epithelium as well as the stromal components of the cervix, endometrium, and myometrium were negative for A-binder. This study shows that A-binder is localized in the uterus, especially in the endocervical glands. The A-binder in the endocervix may have antimicrobial activity in the uterus as in other organs, such as the intestines and mammary glands. (AM J 0BSTET GYNECOL 1988;159:522-6.)
Key words: Vitamin B 12 , R-binder, uterus, immunohistochemistry Vitamin B 12 R-binder, a specific binding protein for vitamin B 12 , is ubiquitous in body fluids, granulocytes, and plasma. 1· 5 It is widely distributed in the glandular epithelium of various human tissues such as the digestive tract, bronchial glands, renal proximal tubules, sweat glands, mammary glands, and prostate gland. 6 • 7 R-binder is speculated to have an antimicrobial function in the intestine and mammary glands. 2 · 8 · 9 Although the uterus is exposed to commensal microorganisms, the precise localization of R-binder in the human uterus has not been reported. Therefore,
From the Laboratory of Anatomic Pathology and Central Clinical Laboratory, Departments of Pathology, Geriatric Medicine, and Obstetrics and Gynecology, Faculty of Medicine, Kyoto University. Received for publication july 14, 1987; revised February 24, 1988; accepted March 5, 1988. Reprint requests: Young Chi Kim, MD, Laboratory of Anatomic Pathology, Kyoto University Hospital, 54 Shogoin-Kawahara-cho, Sakyo-ku, Kyoto 606, japan.
522
we used an immunoperoxidase technique to examine the localization of R-binder in the normal human uterus. Material and methods Cases. Twenty~four surgically removed uterine bodies and 18 cervices were obtained from leiomyomabearing patients between 30 and 53 years old (average 43 years). The specimens were fixed in 10% formalin and embedded in paraffin. Freshly cut 4 1-Lm thick sections were stained with hematoxylin-eosin; they were examined and confirmed to have normal endometrial and endocervical tissues without inflammatory changes. Endometrial date was determined in 24 endometrial tissues according to the criteria of Noyes et al. 10 Twelve samples were from the proliferative phase and 12 were from the secretory phase. These paraffin-embedded sections were used for the study of immunohistochemical localization of the R-binder.