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Three monoclonal antibodies, one directed against cytokeratin (clone 80) and two directed against neurofilament (clones 2F11 and 3G6), were used in the study of a series of 77 lung carcinomas by immunohistochemical staining. The anti-cytokeratin antibody, a very broadly reacting antibody directed against an antigenic determinant common to a great number of cytokeratins, was applicable on frozen sections. The two anti-neurofilament antibodies, directed against the 70 kD protein (clone 2F11) and the 160 kD and 200 kD proteins (clone 3G6) of neurofilament, were applicable on both frozen sections and paraffin sections. The staining results on the lung carcinomas indicate that all types of tumors studied, including small-cell anaplastic carcinoma, are markedly positive for cytokeratin. Frozen sections of five and formalin-fixed and paraffin-embedded sections of six other small-cell anaplastic carcinomas were negative with both anti-neurofilament monoclonal antibodies. One poorly differentiated squamous cell carcinoma positive with anti-neurofilament clone 2F11 but negative with clone 3G6. This distribution of cytoskeletal proteins demonstrates the epithelial differentiation of all types of lung carcinomas. Neuroendocrine differentiation of lung carcinomas as found in the small-cell anaplastic types does not result in expression of neurofilament proteins.

The recently developed postembedding immunoelectron microscopic technique using low temperature embedding in Lowicryl K4M has been applied for the localization and relative quantitation of nephritogenic antibodies in rats with nephrotoxic serum nephritis. Nephrotoxic serum nephritis with different degrees of severity was induced by intravenous administration of increasing doses of rabbit anti-rat glomerular basement membrane antiserum to male Wistar rats. Twenty-four hours after administration, renal tissue was processed for immunoelectron microscopy using Lowicryl embedding after fixation in paraformaldehyde. Thin sections were stained with colloidal gold-labeled antibodies to rabbit IgG. By morphometric analysis the amount of gold label per nanometer of glomerular basement membrane was counted and a strong correlation was found with the amount of administered antiserum. These data show that postembedding immunoelectron microscopy using low temperature embedding in Lowicryl K4M and immunogold staining can be applied to study the localization and relative quantitation of tissue-bound immunoglobulins.

Insulin concentrations in amniotic fluid were correlated with fetal age and with fetal weight in order to test the hypothesis that fetal insulin regulates fetal growth. No significant correlation could be detected. Insulin levels in amniotic fluid in diabetics, however, were significantly higher than in nondiabetics. In the same samples of amniotic fluid C-peptide proved to be very unstable during long term storage.

In a small series of pregnancies complicated by severe fetal growth retardation we found reduction of fetal endocrine pancreatic tissues and of the insulin producing beta cells.

Alterations in glomerular function and structure were studied in protein-overload nephrosis in the rat induced by intraperitoneal administration of bovine serum albumin (BSA). Fractional clearance (C/GFR) studies using inulin and tracer proteins of different molecular size and charge revealed in proteinuric rats 1) unchanged glomerular filtration rate and renal plasma flow; 2) a 34-fold increase in C/GFR of rat serum albumin, reaching values similar to BSA; 3) a 2-fold increase in C/GFR for anionic horse radish peroxidase (HRP), but normal values for neutral and cationic HRP, and 4) an 11- and 3-fold increase for heterologous IgG and IgM, respectively. Glomerular epithelial cells showed degenerative changes, but the distribution of anionic sites in the glomerular basement membrane was found to be unaltered, as determined by polyethyleneimine binding studies. In summary, an elevation of serum albumin concentration resulted in an increased transcapillary albumin transport. This was found to lead to degenerative changes of glomerular epithelial cells with development of large pore defects, which were completely reversible.

This case report concerns a late pregnancy complication, clinically apparent as severe variable decelerations in the first stage of labor. Emergency cesarean section delivered a mildly asphyxiated full-term newborn infant. Examination of the umbilical cord revealed a thrombus of the right umbilical artery, near the fetal side, confirmed by histological examination. The total length of the umbilical cord, only 30 cm, was below the limit necessary for uncomplicated delivery of the fetus near term. Transient stretching during fetal descent is thought to be responsible for constriction of the umbilical arteries, blood flow sludging and thrombosis. Although only a few cases have been reported, thrombosis of the umbilical vessels has to be considered whenever the fetal heart rate pattern shows unexplained variable decelerations.

The effect of maternal hyperalimentation on intrauterine growth retardation was studied by performing unilateral uterine vessel ligation on day 17 in Wistar rats. Test animals were given food supplements by gavage for three days postoperatively whereas control animals received saline. The caloric intake and weight gain of the test dams was significantly greater than that of the controls from days 17 to 20 but not over the longer period, day 14 to 23. The survival and growth of fetuses in the unoperated horn were similar in test and control rats. Fetal survival in the ligated horn was doubled by maternal food supplementation but the growth and development of the survivors were not improved.

Simultaneous biochemical and electron microscopical investigations on surgically removed spleens yielded evidence for the presence of reverse transcriptase containing (Retra) virus in two patients with hematological malignancies with spleen involvement. In three other patients with hematological diseases and in one control patient, the spleens were negative in both assays. The results of these combined studies support the view, that retraviruses are present in human malignancies.

During human pregnancy an enlargement of the islets of Langerhans and hyperplasia of the beta cells is present. These morphological changes indicate that the endocrine pancreas is able to adapt to the metabolic changes of pregnancy.

Intrauterine growth retardation (IUGR) was induced in rats by uterine artery ligation according to Wigglesworth. Control and growth-retarded animals were studied at days 21 and 22 of fetal life and 2 h after spontaneous birth. Fetuses with IUGR, when compared to controls, showed significantly lower glycemia and insulinemia levels. Newborn rats with IUGR had reduced glycemia levels but identical insulin values in comparison to controls. Dysmature and control animals had significantly different absolute weights of endocrine pancreas, but they had equal amounts of endocrine pancreatic tissue in proportion to their total body weight. Within the endocrine pancreas the same number of islet cells was counted in dysmature and control animals, but the animals with IUGR ended up with a reduced percentage of insulin-containing granulated B cells after birth.