Search PubMed⌕ Search

Biomedical subjects

J C Lamb

Publications and source records attributed to J C Lamb.

At least 73 records · Page 4Linked to original sources
PubMed1981

Estrogen action in the mouse uterus: differential nuclear localization of estradiol in uterine cell types.

Autoradiographic studies of labeled steroid uptake in mouse uterine tissue indicated that labeled estradiol was predominantly sequestered in the nuclei of stromal and glandular epithelial cells at 1 h. Luminal epithelial cells did not show appreciable nuclear accumulation of labeled estradiol until 7-8 h after hormone injection. Studies using non-target tissues and unlabeled steroids indicated that the nuclear uptake events were tissue and estrogen steroid specific. The temporal pattern of steroid hormone uptake in the uterus would suggest that an initial interaction in stromal and glandular epithelial cells may be required prior to nuclear stimulation in the luminal epithelial target cell.

Animals↗
PubMed1981

Visualization by light and scanning electron microscopy of reproductive tract lesions in female mice treated transplacentally with diethylstilbestrol.

Pregnant female mice were exposed to diethylstilbestrol or 11 beta-methoxy-17 beta-estradiol on Days 9 to 16 of gestation. The female offspring of these animals were then examined for reproductive tract abnormalities. Scanning electron microscopic and histological evaluation of these specimens demonstrated reproductive tract lesions in all treatment groups when compared to matched control mice. These lesions included apparent displacement of the squamocolumnar junction, uterine squamous metaplasia, atypical uterine cell surface specializations, protrusions of uterine cells, vaginal and cervical papillary growths, enlarged uterine cervix, abnormal vaginal and uterine folding patterns, female hypospadias, and the presence of vaginal concretions. Scanning electron microscopic observations proved particularly useful in studying lesions which involved the disruption of the normal structure and shape of the reproductive tract and the displacement of cell types.

Animals↗
PubMed1979

Age-dependent morphological changes in the seminal colliculus in male mice. Light and scanning electron microscopic study.

The developmental changes in the seminal colliculus of male mice were studied by light and scanning electron microscopy. The epithelium of the mouse seminal colliculus is transformed to the mature epithelium between 20 and 25 days of age, while the transformation of the remaining urethral wall occurred from 5 to 10 days of age. During the process of this epithelial transformation at the seminal colliculus unusual structures, including prominent epithelial proliferations and protrusions, were observed in the area adjacent to the ejaculatory duct openings and the ventral area of the upper medial region of the seminal colliculus in 15-day-old mice. In these unusual structures, three types of cells were recognized by their surface characteristics: cells which had distinct borders and ruffled cell surfaces with microridges; cells which had distinct borders and flat or slightly ruffled cell surfaces with many short microvilli, and small cells which had rounded cell surfaces with many long microvilli. In the remaining area of the seminal colliculus, two types of cells were distinguished: those which had flat or slightly rounded cell surfaces with many short microvilli and those cells with many long microvilli similar to the ones in the previously described area. In 25-day-old mice, the unusual protruding structures were not observed, but some cells with ruffled surfaces were still seen.

Age Factors↗
PubMed1979

Evaluation of the transplacental toxicity of diethylstilbestrol with the scanning electron microscope.

Exposure in utero to the synthetic estrogen diethylstilbestrol (DES) is associated with reproductive tract lesions in male and female CD-1 mice. The scanning electron microscope was used to evaluate the luminal surface of the vagina, cervix, and uterus following prenatal exposure to DES. Abnormalities that have been observed include urethral openings in the cervicovaginal area, squamous metaplasia of the uterus, glandular elements in the vagina, and abnormal cell surface features in the vaginal epithelium.

Animals↗
PubMed1977

The collicular recess organ: evidence for structural and secretory specialization of the ventricular lining in the collicular recess.

The collicular recess organ and adjacent portions of the collicular recess were studied by light microscopy, scanning electron microscopy and transmission electron microscopy. In the collicular recess, the ventricular wall contains folds and is well vascularized. The adluminal ependymal cells generally bear kinocilia and microvilli on their ventricular surface. Among the cilia, many secretory droplets, some axons, and few supraependymal cells are seen. Various stages of apocrine ependymosecretion are observed. In addition to tanycytes, coelocytes are found scattered throughout the ependymal lining of the collicular recess. Coelocytes, characterized by lumina containing cilia and a few microvilli, are accumulated in ependymal and hypependymal positions of the collicular recess organ at the roof of the collicular recess.

Animals↗
PubMed1976

Effect of hepatic venous outflow obstruction on pores and fenestration in sinusoidal endothelium.

The ultrastructure of pores and fenestrations in hepatic sinusoidal endothelial cells was examined following partial surgical occlusion of the suprahepatic portion of the inferior vena cava. Within 12 h after partial obstruction of hepatic venous outflow, endothelial pores (less than 0-1 mum in diameter) and sieve plates in the distal halves of sinusoids were greatly reduced in number or were totally absent, and they were replaced by large fenestration (less than 1-0 mum in diameter). These results suggest that pores forming sieve plates may fuse to form large fenestrations. The findings also indicate that sinusoidal hypertension and hypoxia associated with obstruction of hepatic venous outflow alter the distribution of pores and fenestrations in sinusoidal endothelium

Animals↗
PubMedDate not supplied

The effects of ethylene glycol monomethyl ether on testicular histology in F344 rats.

Ethylene glycol monomethyl ether (EGME) has been found to produce testicular atrophy in experimental rodents. The studies that follow were designed to determine the testicular cell type(s) most susceptible to EGME administration. For histologic studies, F344 rats were gavaged with 150 mg/kg/day of EGME 5 days per week, and serially sacrificed. In sections from perfusion-fixed tissue, necrotic changes were observed in some meiotic and premeiotic spermatocytes 24 hours after a single dose. Also, nuclear condensation was seen in occasional early pachytene spermatocytes. These effects were magnified after two doses; there were more necrotic pachytene and meiotic spermatocytes than necrotic stage I pachytene spermatocytes. By day 4, testes from all treated animals were affected; there was a pronounced maturation-depletion effect, seen as the absence of round spermatids from tubules in stages I to III. These effects continued to develop at days 7 and 10, leaving only Sertoli cells, spermatogonia, and late stage spermatids populating the epithelium. Other animals were treated similarly, but subject to efferent duct ligation 16 hours prior to sacrifice. Fluid production, as judged by weight gain in the testes after efferent duct ligation, was unaffected by EGME treatment. Analysis of the fluid collected at the rete testis indicated that there was no treatment-related change in the relative amounts of androgen binding protein. The data indicate that the spermatocyte is the primary target cell for the histologic effects of EGME in the testis of F344 rats.

Animals↗
PubMedDate not supplied

Dimethyl methyl phosphonate induction of dominant lethal mutations in male mice.

The reproductive toxicity of dimethyl methyl phosphonate (DMMP) was studied in the male B6C3F1 mouse. Male mice were treated with 0, 250, 500, 1000, and 2000 mg/kg DMMP by gavage 5 days per week for 13 weeks. After 4, 8 and 12 weeks of treatment the male mice were mated to untreated CD-1 female mice. At the two highest doses (1000 and 2000 mg/kg) the chemical caused a dominant lethal effect (early resorptions). Groups of male mice (at 1000 and 2000 mg/kg), mated after a 15-week recovery period without chemical dosing, had a resorption rate comparable to the control group. After 13 weeks of dosing, the male mice showed no histopathologic changes of the reproductive organs, no abnormalities in sperm concentration or sperm morphology, no evidence for hormone imbalance, no signs of general toxicity, and no effects on the fertilization rate. The male B6C3F1 mouse was less responsive than the male Fischer 344/N rat to the reproductive toxic effects of DMMP.

Animals↗