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Determination of phosphatidylglycerol
346
Correspondence Am. J.
vesicles). The latter are prominent and basic characteristic elements of the smooth muscle cell structure that makes up 15% of the stroma (lamina propria) of the cervix. In addition, there is a dense body (circle} on the left side of the arrow indicating the “basal lamina” inside the cytoplasm. We think that the authors could find the myofilaments (thick and thin), longitudinally or transversely sectioned, in their electron micrographs. Second, in regard to Fig. 9, we believe that the cell considered as subcolumnar in nature is a lymphocyte. This type of cell, migrating between the epithelial cells, constitutes the extraneous cells of the epithelium and normally represents a part of the immunologic defenses of organisms against invasion of antigens from the environment. Unfortunately, the magnification (~4,200) is too low for identification of the characteristics of Iymphocytes in that cell, but the structure of the nucleus and the clear cytoplasmic rim around it denote the nature of a lymphocyte. Additionally, the ameboid movements, to which the authors refer, are also evidence in favor of our suggestions. A. Athanasiadis, M.D. G. G. Kanakoudis 2nd University Clinic qf Obstetrics and Gynaecology University of Salonica Salonica, Greece
Determination of phosphatidylglycerol To the Editors: We have read with interest the article, entitled “Neonatal respiratory distress in the presence of amniotic fluid phosphatidylglycerol” (Anderson, C. W., Conrad, L., and Cordero, L.: AM. J. OBSTET. GYNECOL. 143233, 1982). The authors describe a neonate who developed hyaline membrane disease although the prenatal amniotic fluid lung profile was mature. The results included a lecithinfsphingomyelin ratio of 3 : 1 and the presence of phosphatidylglycerol (PC). Following delivery, congenital hypothyroidism was diagnosed. The authors suggested that the relationship previously demonstrated in animal studies, between hypothyroidism and altered lung structure, including increased interstitial edema, may explain symptoms of neonatal respiratory distress despite the presence of mature biochemical indices, such as PG. As Anderson and associates point out, hypothyroidism is a potential explanation for the findings in this case. However, there is an alternate explanation that needs to be discussed because of its clinical implications. The one-dimensional technique that the authors cited’ can, on occasion, be misleading and show PG to be present when it is not. We have previously evaluated this one-dimensional technique for determining PG and compared it to the more widely used two-dimensional Gluck technique? Each of 59 amniotic fluid samples was divided into two aliquots, which were then chromatographed by the one- and two-dimensional methods. When the one- and two-dimensional plates
June 1. 1983 Obstet. Gynecol.
were compared for each amniotic fluid sample, in some cases the one-dimensional plate was found to have a spot present that was indistinguishable from PG, although there was clearly none on the two-dimensional plate. We concluded that some amniotic fluid samples contain interfering substances which migrate in the same area on the one-dimensional plate as PG. This can lead to false positive results. Because one-dimensional techniques are being used with increasing frequency,” recognition of this problem is of considerable clinical importance, We suggest that before any one-dimensional lipid separation is adopted for clinical use, it should be critically compared to the two-dimensional procedure. Thomas L. Gross, M.D. George M. Kazzi, M.D. Robert J. Sokol, M.D. Department qf Obstetrics and Gynecology 3395 Scranton Road Cleveland, Ohio 44 109 REFERENCES
1. Tsai, M. Y., and Marshall, J. G.: Phosphatidylglycerot in 261 samples of amniotic fluid from normal and diabetic pregnancies, as measured by one-dimensional thin-layer chromatography, Clin. Chem. 25:682, 1979. 2. Gross, T. L., Wilson, M. V., Kuhnert, P. M., et al.: Clinical laboratory determination of phosphatidylglycerol: Oneand two-dimensional chromatography compared, Clin. Chem. 27:486, 1981. 3. Yambao, T. J., Clarke, D., Smith, C., et al.: Amniotic fluid phosphatidylglycerol in stressed pregnancies, AM. J. OBSTET. GYNECOL. 141: 191, 1981.
Laparoelytrotomy To the Editors: I read with interest the report by Goodlin and associates, entitled “Laparoelytrotomy or abdominal delivery without uterine incision” (AM. J. OBSTET. GYNECOL. 144:990, 1982). Although I find it surprising that experienced obstetrician-gynecologists would not be able to appreciate initially that a surgical incision has been made in the vagina rather than the uterus, I am even more surprised that, in the one case of five that is delineated in detail, a fetus in the second stage of labor at the +2 station in the left occipitotransverse position (without any mention made of either molding or asynclitism of the fetal head, thus implying an engaged head without clinical evidence of cephalopelvic disproportion) cannot be safely and skillfully delivered transvaginally at less total risk to both mother and fetus than transabdominally (with the latter’s greater risk, in my opinion, under the circumstances, for both mother and fetus together). Transvaginal delivery might be accomplished not only by midforceps rotation and extraction but also by manual rotation with possible spontaneous expulsion once rotated or with use of a vacuum extractor. Although I do not deny that there may well be a place for laparoelytrotomy in the armamentarium of the accomplished obstetrician-gynecologist, even if its
Correspondence Am. J.
vesicles). The latter are prominent and basic characteristic elements of the smooth muscle cell structure that makes up 15% of the stroma (lamina propria) of the cervix. In addition, there is a dense body (circle} on the left side of the arrow indicating the “basal lamina” inside the cytoplasm. We think that the authors could find the myofilaments (thick and thin), longitudinally or transversely sectioned, in their electron micrographs. Second, in regard to Fig. 9, we believe that the cell considered as subcolumnar in nature is a lymphocyte. This type of cell, migrating between the epithelial cells, constitutes the extraneous cells of the epithelium and normally represents a part of the immunologic defenses of organisms against invasion of antigens from the environment. Unfortunately, the magnification (~4,200) is too low for identification of the characteristics of Iymphocytes in that cell, but the structure of the nucleus and the clear cytoplasmic rim around it denote the nature of a lymphocyte. Additionally, the ameboid movements, to which the authors refer, are also evidence in favor of our suggestions. A. Athanasiadis, M.D. G. G. Kanakoudis 2nd University Clinic qf Obstetrics and Gynaecology University of Salonica Salonica, Greece
Determination of phosphatidylglycerol To the Editors: We have read with interest the article, entitled “Neonatal respiratory distress in the presence of amniotic fluid phosphatidylglycerol” (Anderson, C. W., Conrad, L., and Cordero, L.: AM. J. OBSTET. GYNECOL. 143233, 1982). The authors describe a neonate who developed hyaline membrane disease although the prenatal amniotic fluid lung profile was mature. The results included a lecithinfsphingomyelin ratio of 3 : 1 and the presence of phosphatidylglycerol (PC). Following delivery, congenital hypothyroidism was diagnosed. The authors suggested that the relationship previously demonstrated in animal studies, between hypothyroidism and altered lung structure, including increased interstitial edema, may explain symptoms of neonatal respiratory distress despite the presence of mature biochemical indices, such as PG. As Anderson and associates point out, hypothyroidism is a potential explanation for the findings in this case. However, there is an alternate explanation that needs to be discussed because of its clinical implications. The one-dimensional technique that the authors cited’ can, on occasion, be misleading and show PG to be present when it is not. We have previously evaluated this one-dimensional technique for determining PG and compared it to the more widely used two-dimensional Gluck technique? Each of 59 amniotic fluid samples was divided into two aliquots, which were then chromatographed by the one- and two-dimensional methods. When the one- and two-dimensional plates
June 1. 1983 Obstet. Gynecol.
were compared for each amniotic fluid sample, in some cases the one-dimensional plate was found to have a spot present that was indistinguishable from PG, although there was clearly none on the two-dimensional plate. We concluded that some amniotic fluid samples contain interfering substances which migrate in the same area on the one-dimensional plate as PG. This can lead to false positive results. Because one-dimensional techniques are being used with increasing frequency,” recognition of this problem is of considerable clinical importance, We suggest that before any one-dimensional lipid separation is adopted for clinical use, it should be critically compared to the two-dimensional procedure. Thomas L. Gross, M.D. George M. Kazzi, M.D. Robert J. Sokol, M.D. Department qf Obstetrics and Gynecology 3395 Scranton Road Cleveland, Ohio 44 109 REFERENCES
1. Tsai, M. Y., and Marshall, J. G.: Phosphatidylglycerot in 261 samples of amniotic fluid from normal and diabetic pregnancies, as measured by one-dimensional thin-layer chromatography, Clin. Chem. 25:682, 1979. 2. Gross, T. L., Wilson, M. V., Kuhnert, P. M., et al.: Clinical laboratory determination of phosphatidylglycerol: Oneand two-dimensional chromatography compared, Clin. Chem. 27:486, 1981. 3. Yambao, T. J., Clarke, D., Smith, C., et al.: Amniotic fluid phosphatidylglycerol in stressed pregnancies, AM. J. OBSTET. GYNECOL. 141: 191, 1981.
Laparoelytrotomy To the Editors: I read with interest the report by Goodlin and associates, entitled “Laparoelytrotomy or abdominal delivery without uterine incision” (AM. J. OBSTET. GYNECOL. 144:990, 1982). Although I find it surprising that experienced obstetrician-gynecologists would not be able to appreciate initially that a surgical incision has been made in the vagina rather than the uterus, I am even more surprised that, in the one case of five that is delineated in detail, a fetus in the second stage of labor at the +2 station in the left occipitotransverse position (without any mention made of either molding or asynclitism of the fetal head, thus implying an engaged head without clinical evidence of cephalopelvic disproportion) cannot be safely and skillfully delivered transvaginally at less total risk to both mother and fetus than transabdominally (with the latter’s greater risk, in my opinion, under the circumstances, for both mother and fetus together). Transvaginal delivery might be accomplished not only by midforceps rotation and extraction but also by manual rotation with possible spontaneous expulsion once rotated or with use of a vacuum extractor. Although I do not deny that there may well be a place for laparoelytrotomy in the armamentarium of the accomplished obstetrician-gynecologist, even if its