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Peroxidative and glutathione status in uterus and placenta after normal and pathological pregnancy
Exp Toxic Patho11997; 49: 497-500 Gustav Fischer Verlag
Institute of Phannacology and Toxicology, Clinic of Obstetrics and Gynaecology*, Medical Faculty, Friedrich Schiller University Jena, Gennany
Peroxidative and glutathione status in uterus and placenta after normal and pathological pregnancy A. BARTH, G. PElKER*, W. GROSS*, S. SCHRODER*, and W. MICHELS* With 2 figures Received: September 7, 1996; Accepted: September 18, 1996 Address for correspondence: PD Dr. ASTRID BARTH, Institute of Phannacology and Toxicology, Friedrich Schiller University Jena, D-07740 Jena, Gennany. Key words: Pregnancy, pathological; Lipid peroxidation; Glutathione; Pregnancy, nonnal; Uterus, human; Placenta, human.
Summary In 10 women with disturbed pregnancies without hypertension, reduced (GSH) and oxidized glutathione (GSSG) as well as lipid peroxides as thiobarbituric acid reactive substances (TBARS) were detennined in the placenta and in the uterine tissue after unexpected stress-induced Caesarian section (group II). Production of TBARS was also measured in vitro in the 9000 x g supernatant of both tissues. The results were compared with those from women after nonnal pregnancy and expected Caesarian section (group I). After normal pregnancy higher TBARS and lower GSH with higher GSSG/GSH ratio were found in the placenta in comparison to the uterine tissue, indicating an oxidant/antioxidant imbalance in the placenta. No statistically significant differences were shown between the parameters of groups I and II. The possible oxidant stress associated with disturbed pregnancy and subsequent unexpected Caesarian section in this study was insufficient to alter tissue levels of glutathione nor the peroxidative status of placenta and uterus.
Introduction An oxidant/antioxidant imbalance has been suggested among the pathogenetic factors involved in preeclampsia (ISHIHARA 1978; STRATTA et al. 1994). In pregnancyinduced hypertension, enhanced lipid peroxidation products were found in the maternal serum as well as in erythrocytes during pregnancy and early puerperium (PEIKER et al. 1992; WALSH 1994; KABI et al. 1994). The sources of lipid peroxides may be the trophoplast cells of preeclamptic placentas (WALSH and WANG 1995). The importance of lipid peroxidation concerning disturbed
pregnancy are unknown. According to HUBEL et al. (1989); WALSH (1994); WALSHP and WANG (1993b, 1995) the human placenta secretes lipid peroxides and thromboxane into the maternal effluent. In preeclampsia, deficient glutathione peroxidase activity in the placenta was followed by an increase of lipid peroxides and thromboxane (W ALSH and WANG 1993a). Low dose aspirin was found to be effective in the prevention of preeclampsia due to inhibition of lipid peroxides and thromboxane production in the preeclamptic placenta (WANG and WALSH 1995). It was the aim of these investigations to find out differences in the glutathione content and/or lipid peroxidation of uterus and placenta after disturbed pregnancy without hypertension to reveal the effects of oxidative stress occurring in the fetal-to-neonatal transition, and possibly a new therapeutic conception. Also in pathologic pregnancies other than preeclampsia, lipid peroxides were enhanced via depletion of GSH in the blood (TABACOV A et al. 1994a, b). Patients were assigned to group I of normal pregnancy (twins, irregular position of the fetus) or group II of pathological pregnancy (threatening spontaneous abortion, toxemia, oligohydramnion, fetal retardation). Immediately after normal Caesarian section (group I) or after unexpected stress-induced Caesarian section (group II) uterine and placental tissues were deep-frozen. In both organs, lipid peroxides, iron stimulated lipid peroxidation and reduced and oxidized glutathione were measured, in order to get information about sources oflipid peroxides and the antioxidative capacity of uterus and placenta after disturbed pregnancy. Exp Toxic Pathol49 (1997) 6
497
Material and methods Subjects: In 5-9 women with normal pregnancy and expected Caesarian section (I) and 10 women with pathological pregnancy and unexpected, stress-induced Caesarian section (II), small pieces of uterine and placental tissues were frozen in liquid nitrogen. The following reasons for the primary Caesarian section were summarized in group I: symphysial stretching, rhesus incompatibility, breech or transverse presentations, placenta praevia, ovarian tumour, twins. Patients of group II are pregnant women with pathological cardiotocogram or Doppler flow, premature rupture of the amnion, premature and dry labour in case of the beginnings of amniotic infection, severe fetal retardation and oligohydramnion in case of chronic pyelonephritis, pathological cardiotocogram and hydramnion. Patients suffering from severe pregnancy-induced hypertension did not belong to our indication catalogue. Methods: Glutathione (GSH) was measured spectrophotometrically according to ELLMAN (1959), oxidized glutathione (GSSG) fluorimetrically according to HISSIN and HILF (1976). For the determination of lipid peroxides, thiobarbituric acid reactive substances (TBARS) were measured fluorimetrically as malondialdehyde equivalents according to YAGI (1987). The results were referred to wet weight because the protein contents of uterine and placental tissues did not differ. To determine stimulated lipid peroxidation (LPO) in the 9000 x g supernatant, the uterine and the placental tissues were homogenized with 2 volumes of 0.1 M sodium phosphate buffer pH 7.4 and centrifuged at 9000 x g for 20 min at a dc. Supernatant protein content was estimated by the biuret method according to KLINGER and MULLER (1974). The iron stimulated NADPH-dependent LPO was determined using the thiobarbituric acid assay (BUEGE and AUST 1978; BARTH and BERNST 1992). The results are given as arithmetic means ± S.E.M. For statistical analysis Student's t-test was used (p < 0.05).
18
.n..m ~O ~I~ T= BA ~R ~S~/g~______________________-, r-
.......
16
~
,12 - ---------.----.--- ........ ---- .... ----
10
...................................... .
8
.............•.......................
6 .....• ................ ..•...•.••.•....
---- .------------
4
...."
....... .
2
o
n=5 I
n=10 II
n=9 I
n=10 II
placerta
Fig. 1. Lipid peroxides as thiobarbituric acid reactive substances (TBARS) in placenta and uterus tissue, measured as malondialdehyde equivalents using a Hitachi-F-2000 Fluorescence-Spectrophotometer after nonnal (I) and stress-induced unexpected Caesarian section (II). Arithmetic means ± S.E.M.
nag n ~1 0 I II pIacem
Results Three times higher concentrations of lipid peroxides were found in the placenta in relation to uterine tissue. But no statistically significant differences of TBARS were seen in uterus and placenta after normal (group I) and pathological pregnancies (group II) (fig. 1). Neither the antioxidant GSH nor GSSG as a marker for oxidative stress were changed in uterus and placenta after disturbed pregnancy (fig. 2). There are remarkable higher GSH concentrations in the uterine tissue compared to placenta. After normal pregnancies (group I) the ratio of GSSG/GSH, demonstrating the oxidized proportion of glutathione at the time of Caesarian section, is higher in placental (0.27) than in uterine (0.18) tissue. But nearly the same ratios were found in placenta (0.26) and uterus (0.19) of group II. NADPH-dependent, iron stimulated lipid peroxidation in the 9000 x g supernatant of placenta and uterus, mea498
Exp Toxic Patho149 (1997) 6
Fig. 2. Reduced (GSH) and oxidized glutathione (GSSG) in placenta and uterus tissue after normal (I) and stress-induced unexpected Caesarian section (II). Arithmetic means ± S.E.M.
sured as TBARS production rate, was not changed in both tissues after disturbed pregnancy (group I: placenta 0.279 ± 0.018, uterus 0.054 ± 0.016 nmol TBARS/mg x min; group II: placenta 0.264 ± 0.017, uterus 0.069 ± 0.018 nmol TBARS/mg x min).
Discussion Higher circulating levels of lipid peroxides in women with pregnancy-induced hypertension or maternal toxe-
mia are well established (PEIKER et al. 1992; WALSH and WANG 1993a; WALSH 1994). The human placenta was found to secrete lipid peroxides (WALSH and WANG 1993b, 1995). BANERJEE et al. (1993) provided evidence for the existence of substances in the human placenta which elevated lipid peroxidation, decreased glutathione levels and changed glutathione-related enzyme activities in recipients of placental extract. In previous investigations plasma glutathione concentrations were surprisingly enhanced, and alpha-tocopherol, selenium and copper serum levels were unchanged in patients with pregnancy-induced hypertension. These results together with normal serum glutathione peroxidase activity led to the assumption that lipid peroxidation is more a consequence than a reason of preeclampsia (PElKER et al. 1992). Vitamin E supplementation in preeclampsia did not exert favorable effects on maternal hypertension and fetal outcome, either (STRATTA et al. 1994). Now we investigated women with pathological pregnancy other than preeclampsia and found only a tendency towards higher TBARS in placenta and uterine tissue (fig. O. Rise in the levels of oxidized glutathione indicates increased free radical-induced oxidative activity in the cells. Higher ratios of GSSG/GSH in placenta compared to uterus tissue can be hypothesized as higher consumption of GSH after formation of oxygen radicals in the placenta, but this process was not different in women with unexpected stress-induced Caesarian section (fig. 2). In the 9000 x g supernatant of human placenta smooth endoplasmic reticulum and cytochrome P 450 dependent biotransformation activities have been detected (TRAEGER et al. 1972). Under certain conditions such as induction or iron stimulation, cyct P 450 may generate an extensive amount of oxygen radicals and H 202, which are able to breakdown polyunsaturated fatty acids resulting in a marked increase of TBARS. In the 9000 x g supernatant with the NADPH-cyt P 450 system malondialdehyde represents the major TBARS in the peroxidized endoplasmic reticulum lipids (TOMITA et al. 1990; DRAPER et al. 1993). As seen from our results, the susceptibility to in vitro lipid peroxidation was much higher in the placenta than in the uterine tissue, but similar amounts of TBARS were produced in both tissues of groups I and II. The results obtained agree with an oxidant/antioxidant imbalance in the placenta compared to uterine tissue at the end of a normal pregnancy (SASTRE et al. 1994). The possible oxidant stress associated with disturbed pregnancy and unexpected Caesarian section in this study was insufficient to alter tissue levels of glutathione nor peroxidative status of placenta and uterus. These results do not support an antioxidant or glutathione-enhancing therapy alone to improve maternal and fetal outcome after severe disturbances of pregnancy leading to unexpected Caesarian section. Acknowledgement: We gratefully acknowledge the skilled technical assistance of HElKE STADLER.
References BANERJEE KK, BISHAYEE A, CHATTERJEE M: Elevated lipid peroxidation, decreased glutathione level and changes in glutathione-related enzymes in rats treated with human placental extract. Acta Medica Okayama 1993; 47: 223-227. BARTH A, BERNST M: Influence of bile acids on stimulated lipid peroxidation and hydrogen peroxide production in rat liver microsomes. Exp Toxic Pathol 1992; 44: 399-405. BUEGE JKA, AUST SD: Microsomal lipid peroxidation. Methods Enzymol1978; 52: 302-310. DRAPER HH, SQUIRES EJ, MAHMOOD! H, et al.: A comparative evaluation of thiobarbituric acid methods for the determination of malondialdehyde in biological materials. Free Radical Bioi Med 1993; 15: 353-363. ELLMAN GL: Tissue sulfhydryl groups. Arch Biochem Biophys 1959;82:70-77. HrssIN PJ, HrLF R: A fluorometric method for determination of oxidized and reduced glutathione in tissues. Anal Biochern 1976; 74: 214-226. HUBEL CA, ROBERTS IN, TAYLOR RN, et al.: Lipid peroxidation in pregnancy: new perspectives on preeclampsia. Am J Obstet Gynecol1989, 161: 1025-1034. ISHIHARA M: Studies on lipid peroxides of normal pregnant women and of patients with toxemia of pregnancy. Clin Chern Acta 1978; 84: 1-9. KABI BC, GOEL N, RAO YN, et al.: Levels of erythrocyte malonyldialdehyde, vitamin-E, reduced glutathione, G6PD activity and plasma urate in patients of pregnancy induced hypertension. Ind J Med Res 1994; 100: 23-25. KLINGER W, MULLER D: The influence of age on protein concentration in serum, liver and kidney of rats determined by various methods. Z Versuchstierk 1974; 16: 19-153. PEIKER G, KRETZSCHMAR M, MOLLER B, et al.: Changes of thiobarbituric acid reactive substances (TBARS), i. e., glutathione, alpha-tocopherol, selenium, and copper during normal and disturbed pregnancy (pregnancy-induced hypertension). Int J Feto-Maternal Med 1992; 5: 155-159. SASTRE J, ASENSI M, RODRIGO F, et al.: Antioxidant administration to the mother prevents oxidative stress associated with birth in the neonatal rat. Life Sciences 1994; 54: 2055-2059. STRATTA P, CANAVESE C, PORCU M, et a1.: Vitamin E supplementation in preeclampsia. Gynecol Obstet Invest 1994;37: 246-249. TABACOVA S, LITTLE RE, BALABAEVA L, et al.: Complications of pregnancy in relation to maternal lipid peroxides, glutathione, and exposure to metals. Reproductive Toxicol 1994a;8: 217-224. TABAcoVA S, BAIRD DD, BALABAEVA L, et al.: Placental arsenic and cadmium in relation to lipid peroxides and glutathione levels in maternal-infant pairs from a copper smelter area. Placenta 1994b; 15: 873-88l. TOMITAM, OKUYAMA T, KAWAI S: Determination of malonaldehyde in oxidized biological materials by high performance liquid chromatography. J Chromatography 1990;515: 391-397. TRAEGER A, HOFFMANN H, FRANKE H, et al.: The influence of phenobarbital on drug-metabolizing enzymes in the human placenta, on the fine structure of the chorionic villi and on the serum bilirubin concentration in the newborns. Z Geburtsh Perinat 1972; 176: 397-402. Exp Toxic Pathol49 (1997) 6
499
WALSH SW: Lipid peroxidation in pregnancy. Hypertension in Pregnancy 1994; 13: 1-32. WALSH SW, WANG YP: Deficient glutathione peroxidase activity in preeclampsia is associated with increased placental production of thromboxane and lipid peroxides. Am J Obstet Gynecol1993a; 169: 1456-1461. WALSH SW, WANG YP: Secretion of lipid peroxides by the human placenta. Am J Obstet Gynecol 1993b; 169: 1462-1466.
Exp Toxic Patho11997; 49: 500 Gustav Fischer Verlag
WALSH SW, WANG YP: Trophoblast and placental villous core production of lipid peroxides, thromboxane, and prostacyclin in preeclampsia. J Clin Endocrinol Metabolism 1995; 80: 1888-1893. WANG YP, WALSH SW: Aspirin inhibits both lipid peroxides and thromboxane in preeclamptic placentas. Free Rad BioI Med 1995; 18: 585-591. Y AGI K: Lipid peroxides and human diseases. Chern Phys Lipids 1987; 45: 337-351.
Book review
Color AtIasrrext of Salivary Gland Tumor Pathology By IRVING DARDICK 274 pages. IGAKU-Shoin, Medical Publishers, Inc. New York 1996. Hardcover $ 129.50. ISBN (New York) 0-89640-308-4. ISBN (Tokyo) 4-260-14308-5 Diagnostic categorization of salivary gland tumors may be very difficult because there is a considerable variation in histomorphology virtually within any of the subtypes and well-defined criteria as well as knowledge of the interrelationship of the various salivary gland tumors are lacking. In addition most pathologists have only a limited experience with these tumors due to their infrequent occurrence. The volume reviewed here gives both an excellent overview and detailed information on benign and malignant neoplasms of salivary glands with basing on concepts of tumor cell differentiation and specialized extracellular matrix synthesis for explaining the histomorphology. In chapters 2 (normal cell types, architecture and proliferation) and 3 (morphogenesis and pathogenesis) these subjects have in general been discussed. To support the understanding of the text a series of model diagrams are included which show the interactions of cell types and their relations inclusive of their synthetic products. In the chapters dealing with the major classes of salivary tumors small line drawings remind the reader of such basic differentiation processes involved in the respective tumor subtypes. However, the main task of the book is to detail diagnostic criteria and provide appropriate and comprehensive illustrations to assist the pathologist in categorizing salivary gland tumors. Chapter 4 presents past 500
Exp Toxic Pathol 49 (1997) 6
classifications and those in current use, due to its rather widespread use the classification, endorsed by the WHO, is taken as basis (with a few additions and some minor modifications). Chapter 5 presents taxonomic guidelines for diagnostic purposes, in a step-wise fashion the subtypes can systematically be identified by considering key morphologic features. In the following 20 chapters the different classes of salivary gland tumors are explained by a concise text and coloured illustrations of high quality. The text of these chapters is clearly structured: introduction, general diagnostic criteria, differential diagnosis and morphologic development. Light microscopic pictures are supplemented by electron microscopic illustrations if necessary. A selected bibliography at the end of each chapter allows the reader to go into more detail if he wants to do so. The editor hopes that his approaches to salivary gland tumor classification will stimulate continued research and provide a natural evolution for understanding the complexities underlying histomorphology in these neoplasms. In the first place, however, this book will eminently aid in daily diagnostic work and is recommended without reservation to all pathologists who may be confronted with diagnostics of salivary gland tumors. D. KATENKAMP, Jena
Institute of Phannacology and Toxicology, Clinic of Obstetrics and Gynaecology*, Medical Faculty, Friedrich Schiller University Jena, Gennany
Peroxidative and glutathione status in uterus and placenta after normal and pathological pregnancy A. BARTH, G. PElKER*, W. GROSS*, S. SCHRODER*, and W. MICHELS* With 2 figures Received: September 7, 1996; Accepted: September 18, 1996 Address for correspondence: PD Dr. ASTRID BARTH, Institute of Phannacology and Toxicology, Friedrich Schiller University Jena, D-07740 Jena, Gennany. Key words: Pregnancy, pathological; Lipid peroxidation; Glutathione; Pregnancy, nonnal; Uterus, human; Placenta, human.
Summary In 10 women with disturbed pregnancies without hypertension, reduced (GSH) and oxidized glutathione (GSSG) as well as lipid peroxides as thiobarbituric acid reactive substances (TBARS) were detennined in the placenta and in the uterine tissue after unexpected stress-induced Caesarian section (group II). Production of TBARS was also measured in vitro in the 9000 x g supernatant of both tissues. The results were compared with those from women after nonnal pregnancy and expected Caesarian section (group I). After normal pregnancy higher TBARS and lower GSH with higher GSSG/GSH ratio were found in the placenta in comparison to the uterine tissue, indicating an oxidant/antioxidant imbalance in the placenta. No statistically significant differences were shown between the parameters of groups I and II. The possible oxidant stress associated with disturbed pregnancy and subsequent unexpected Caesarian section in this study was insufficient to alter tissue levels of glutathione nor the peroxidative status of placenta and uterus.
Introduction An oxidant/antioxidant imbalance has been suggested among the pathogenetic factors involved in preeclampsia (ISHIHARA 1978; STRATTA et al. 1994). In pregnancyinduced hypertension, enhanced lipid peroxidation products were found in the maternal serum as well as in erythrocytes during pregnancy and early puerperium (PEIKER et al. 1992; WALSH 1994; KABI et al. 1994). The sources of lipid peroxides may be the trophoplast cells of preeclamptic placentas (WALSH and WANG 1995). The importance of lipid peroxidation concerning disturbed
pregnancy are unknown. According to HUBEL et al. (1989); WALSH (1994); WALSHP and WANG (1993b, 1995) the human placenta secretes lipid peroxides and thromboxane into the maternal effluent. In preeclampsia, deficient glutathione peroxidase activity in the placenta was followed by an increase of lipid peroxides and thromboxane (W ALSH and WANG 1993a). Low dose aspirin was found to be effective in the prevention of preeclampsia due to inhibition of lipid peroxides and thromboxane production in the preeclamptic placenta (WANG and WALSH 1995). It was the aim of these investigations to find out differences in the glutathione content and/or lipid peroxidation of uterus and placenta after disturbed pregnancy without hypertension to reveal the effects of oxidative stress occurring in the fetal-to-neonatal transition, and possibly a new therapeutic conception. Also in pathologic pregnancies other than preeclampsia, lipid peroxides were enhanced via depletion of GSH in the blood (TABACOV A et al. 1994a, b). Patients were assigned to group I of normal pregnancy (twins, irregular position of the fetus) or group II of pathological pregnancy (threatening spontaneous abortion, toxemia, oligohydramnion, fetal retardation). Immediately after normal Caesarian section (group I) or after unexpected stress-induced Caesarian section (group II) uterine and placental tissues were deep-frozen. In both organs, lipid peroxides, iron stimulated lipid peroxidation and reduced and oxidized glutathione were measured, in order to get information about sources oflipid peroxides and the antioxidative capacity of uterus and placenta after disturbed pregnancy. Exp Toxic Pathol49 (1997) 6
497
Material and methods Subjects: In 5-9 women with normal pregnancy and expected Caesarian section (I) and 10 women with pathological pregnancy and unexpected, stress-induced Caesarian section (II), small pieces of uterine and placental tissues were frozen in liquid nitrogen. The following reasons for the primary Caesarian section were summarized in group I: symphysial stretching, rhesus incompatibility, breech or transverse presentations, placenta praevia, ovarian tumour, twins. Patients of group II are pregnant women with pathological cardiotocogram or Doppler flow, premature rupture of the amnion, premature and dry labour in case of the beginnings of amniotic infection, severe fetal retardation and oligohydramnion in case of chronic pyelonephritis, pathological cardiotocogram and hydramnion. Patients suffering from severe pregnancy-induced hypertension did not belong to our indication catalogue. Methods: Glutathione (GSH) was measured spectrophotometrically according to ELLMAN (1959), oxidized glutathione (GSSG) fluorimetrically according to HISSIN and HILF (1976). For the determination of lipid peroxides, thiobarbituric acid reactive substances (TBARS) were measured fluorimetrically as malondialdehyde equivalents according to YAGI (1987). The results were referred to wet weight because the protein contents of uterine and placental tissues did not differ. To determine stimulated lipid peroxidation (LPO) in the 9000 x g supernatant, the uterine and the placental tissues were homogenized with 2 volumes of 0.1 M sodium phosphate buffer pH 7.4 and centrifuged at 9000 x g for 20 min at a dc. Supernatant protein content was estimated by the biuret method according to KLINGER and MULLER (1974). The iron stimulated NADPH-dependent LPO was determined using the thiobarbituric acid assay (BUEGE and AUST 1978; BARTH and BERNST 1992). The results are given as arithmetic means ± S.E.M. For statistical analysis Student's t-test was used (p < 0.05).
18
.n..m ~O ~I~ T= BA ~R ~S~/g~______________________-, r-
.......
16
~
,12 - ---------.----.--- ........ ---- .... ----
10
...................................... .
8
.............•.......................
6 .....• ................ ..•...•.••.•....
---- .------------
4
...."
....... .
2
o
n=5 I
n=10 II
n=9 I
n=10 II
placerta
Fig. 1. Lipid peroxides as thiobarbituric acid reactive substances (TBARS) in placenta and uterus tissue, measured as malondialdehyde equivalents using a Hitachi-F-2000 Fluorescence-Spectrophotometer after nonnal (I) and stress-induced unexpected Caesarian section (II). Arithmetic means ± S.E.M.
nag n ~1 0 I II pIacem
Results Three times higher concentrations of lipid peroxides were found in the placenta in relation to uterine tissue. But no statistically significant differences of TBARS were seen in uterus and placenta after normal (group I) and pathological pregnancies (group II) (fig. 1). Neither the antioxidant GSH nor GSSG as a marker for oxidative stress were changed in uterus and placenta after disturbed pregnancy (fig. 2). There are remarkable higher GSH concentrations in the uterine tissue compared to placenta. After normal pregnancies (group I) the ratio of GSSG/GSH, demonstrating the oxidized proportion of glutathione at the time of Caesarian section, is higher in placental (0.27) than in uterine (0.18) tissue. But nearly the same ratios were found in placenta (0.26) and uterus (0.19) of group II. NADPH-dependent, iron stimulated lipid peroxidation in the 9000 x g supernatant of placenta and uterus, mea498
Exp Toxic Patho149 (1997) 6
Fig. 2. Reduced (GSH) and oxidized glutathione (GSSG) in placenta and uterus tissue after normal (I) and stress-induced unexpected Caesarian section (II). Arithmetic means ± S.E.M.
sured as TBARS production rate, was not changed in both tissues after disturbed pregnancy (group I: placenta 0.279 ± 0.018, uterus 0.054 ± 0.016 nmol TBARS/mg x min; group II: placenta 0.264 ± 0.017, uterus 0.069 ± 0.018 nmol TBARS/mg x min).
Discussion Higher circulating levels of lipid peroxides in women with pregnancy-induced hypertension or maternal toxe-
mia are well established (PEIKER et al. 1992; WALSH and WANG 1993a; WALSH 1994). The human placenta was found to secrete lipid peroxides (WALSH and WANG 1993b, 1995). BANERJEE et al. (1993) provided evidence for the existence of substances in the human placenta which elevated lipid peroxidation, decreased glutathione levels and changed glutathione-related enzyme activities in recipients of placental extract. In previous investigations plasma glutathione concentrations were surprisingly enhanced, and alpha-tocopherol, selenium and copper serum levels were unchanged in patients with pregnancy-induced hypertension. These results together with normal serum glutathione peroxidase activity led to the assumption that lipid peroxidation is more a consequence than a reason of preeclampsia (PElKER et al. 1992). Vitamin E supplementation in preeclampsia did not exert favorable effects on maternal hypertension and fetal outcome, either (STRATTA et al. 1994). Now we investigated women with pathological pregnancy other than preeclampsia and found only a tendency towards higher TBARS in placenta and uterine tissue (fig. O. Rise in the levels of oxidized glutathione indicates increased free radical-induced oxidative activity in the cells. Higher ratios of GSSG/GSH in placenta compared to uterus tissue can be hypothesized as higher consumption of GSH after formation of oxygen radicals in the placenta, but this process was not different in women with unexpected stress-induced Caesarian section (fig. 2). In the 9000 x g supernatant of human placenta smooth endoplasmic reticulum and cytochrome P 450 dependent biotransformation activities have been detected (TRAEGER et al. 1972). Under certain conditions such as induction or iron stimulation, cyct P 450 may generate an extensive amount of oxygen radicals and H 202, which are able to breakdown polyunsaturated fatty acids resulting in a marked increase of TBARS. In the 9000 x g supernatant with the NADPH-cyt P 450 system malondialdehyde represents the major TBARS in the peroxidized endoplasmic reticulum lipids (TOMITA et al. 1990; DRAPER et al. 1993). As seen from our results, the susceptibility to in vitro lipid peroxidation was much higher in the placenta than in the uterine tissue, but similar amounts of TBARS were produced in both tissues of groups I and II. The results obtained agree with an oxidant/antioxidant imbalance in the placenta compared to uterine tissue at the end of a normal pregnancy (SASTRE et al. 1994). The possible oxidant stress associated with disturbed pregnancy and unexpected Caesarian section in this study was insufficient to alter tissue levels of glutathione nor peroxidative status of placenta and uterus. These results do not support an antioxidant or glutathione-enhancing therapy alone to improve maternal and fetal outcome after severe disturbances of pregnancy leading to unexpected Caesarian section. Acknowledgement: We gratefully acknowledge the skilled technical assistance of HElKE STADLER.
References BANERJEE KK, BISHAYEE A, CHATTERJEE M: Elevated lipid peroxidation, decreased glutathione level and changes in glutathione-related enzymes in rats treated with human placental extract. Acta Medica Okayama 1993; 47: 223-227. BARTH A, BERNST M: Influence of bile acids on stimulated lipid peroxidation and hydrogen peroxide production in rat liver microsomes. Exp Toxic Pathol 1992; 44: 399-405. BUEGE JKA, AUST SD: Microsomal lipid peroxidation. Methods Enzymol1978; 52: 302-310. DRAPER HH, SQUIRES EJ, MAHMOOD! H, et al.: A comparative evaluation of thiobarbituric acid methods for the determination of malondialdehyde in biological materials. Free Radical Bioi Med 1993; 15: 353-363. ELLMAN GL: Tissue sulfhydryl groups. Arch Biochem Biophys 1959;82:70-77. HrssIN PJ, HrLF R: A fluorometric method for determination of oxidized and reduced glutathione in tissues. Anal Biochern 1976; 74: 214-226. HUBEL CA, ROBERTS IN, TAYLOR RN, et al.: Lipid peroxidation in pregnancy: new perspectives on preeclampsia. Am J Obstet Gynecol1989, 161: 1025-1034. ISHIHARA M: Studies on lipid peroxides of normal pregnant women and of patients with toxemia of pregnancy. Clin Chern Acta 1978; 84: 1-9. KABI BC, GOEL N, RAO YN, et al.: Levels of erythrocyte malonyldialdehyde, vitamin-E, reduced glutathione, G6PD activity and plasma urate in patients of pregnancy induced hypertension. Ind J Med Res 1994; 100: 23-25. KLINGER W, MULLER D: The influence of age on protein concentration in serum, liver and kidney of rats determined by various methods. Z Versuchstierk 1974; 16: 19-153. PEIKER G, KRETZSCHMAR M, MOLLER B, et al.: Changes of thiobarbituric acid reactive substances (TBARS), i. e., glutathione, alpha-tocopherol, selenium, and copper during normal and disturbed pregnancy (pregnancy-induced hypertension). Int J Feto-Maternal Med 1992; 5: 155-159. SASTRE J, ASENSI M, RODRIGO F, et al.: Antioxidant administration to the mother prevents oxidative stress associated with birth in the neonatal rat. Life Sciences 1994; 54: 2055-2059. STRATTA P, CANAVESE C, PORCU M, et a1.: Vitamin E supplementation in preeclampsia. Gynecol Obstet Invest 1994;37: 246-249. TABACOVA S, LITTLE RE, BALABAEVA L, et al.: Complications of pregnancy in relation to maternal lipid peroxides, glutathione, and exposure to metals. Reproductive Toxicol 1994a;8: 217-224. TABAcoVA S, BAIRD DD, BALABAEVA L, et al.: Placental arsenic and cadmium in relation to lipid peroxides and glutathione levels in maternal-infant pairs from a copper smelter area. Placenta 1994b; 15: 873-88l. TOMITAM, OKUYAMA T, KAWAI S: Determination of malonaldehyde in oxidized biological materials by high performance liquid chromatography. J Chromatography 1990;515: 391-397. TRAEGER A, HOFFMANN H, FRANKE H, et al.: The influence of phenobarbital on drug-metabolizing enzymes in the human placenta, on the fine structure of the chorionic villi and on the serum bilirubin concentration in the newborns. Z Geburtsh Perinat 1972; 176: 397-402. Exp Toxic Pathol49 (1997) 6
499
WALSH SW: Lipid peroxidation in pregnancy. Hypertension in Pregnancy 1994; 13: 1-32. WALSH SW, WANG YP: Deficient glutathione peroxidase activity in preeclampsia is associated with increased placental production of thromboxane and lipid peroxides. Am J Obstet Gynecol1993a; 169: 1456-1461. WALSH SW, WANG YP: Secretion of lipid peroxides by the human placenta. Am J Obstet Gynecol 1993b; 169: 1462-1466.
Exp Toxic Patho11997; 49: 500 Gustav Fischer Verlag
WALSH SW, WANG YP: Trophoblast and placental villous core production of lipid peroxides, thromboxane, and prostacyclin in preeclampsia. J Clin Endocrinol Metabolism 1995; 80: 1888-1893. WANG YP, WALSH SW: Aspirin inhibits both lipid peroxides and thromboxane in preeclamptic placentas. Free Rad BioI Med 1995; 18: 585-591. Y AGI K: Lipid peroxides and human diseases. Chern Phys Lipids 1987; 45: 337-351.
Book review
Color AtIasrrext of Salivary Gland Tumor Pathology By IRVING DARDICK 274 pages. IGAKU-Shoin, Medical Publishers, Inc. New York 1996. Hardcover $ 129.50. ISBN (New York) 0-89640-308-4. ISBN (Tokyo) 4-260-14308-5 Diagnostic categorization of salivary gland tumors may be very difficult because there is a considerable variation in histomorphology virtually within any of the subtypes and well-defined criteria as well as knowledge of the interrelationship of the various salivary gland tumors are lacking. In addition most pathologists have only a limited experience with these tumors due to their infrequent occurrence. The volume reviewed here gives both an excellent overview and detailed information on benign and malignant neoplasms of salivary glands with basing on concepts of tumor cell differentiation and specialized extracellular matrix synthesis for explaining the histomorphology. In chapters 2 (normal cell types, architecture and proliferation) and 3 (morphogenesis and pathogenesis) these subjects have in general been discussed. To support the understanding of the text a series of model diagrams are included which show the interactions of cell types and their relations inclusive of their synthetic products. In the chapters dealing with the major classes of salivary tumors small line drawings remind the reader of such basic differentiation processes involved in the respective tumor subtypes. However, the main task of the book is to detail diagnostic criteria and provide appropriate and comprehensive illustrations to assist the pathologist in categorizing salivary gland tumors. Chapter 4 presents past 500
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classifications and those in current use, due to its rather widespread use the classification, endorsed by the WHO, is taken as basis (with a few additions and some minor modifications). Chapter 5 presents taxonomic guidelines for diagnostic purposes, in a step-wise fashion the subtypes can systematically be identified by considering key morphologic features. In the following 20 chapters the different classes of salivary gland tumors are explained by a concise text and coloured illustrations of high quality. The text of these chapters is clearly structured: introduction, general diagnostic criteria, differential diagnosis and morphologic development. Light microscopic pictures are supplemented by electron microscopic illustrations if necessary. A selected bibliography at the end of each chapter allows the reader to go into more detail if he wants to do so. The editor hopes that his approaches to salivary gland tumor classification will stimulate continued research and provide a natural evolution for understanding the complexities underlying histomorphology in these neoplasms. In the first place, however, this book will eminently aid in daily diagnostic work and is recommended without reservation to all pathologists who may be confronted with diagnostics of salivary gland tumors. D. KATENKAMP, Jena