Biomedical subjects

S J Hall

Publications and source records attributed to S J Hall.

79 records · Page 5Linked to original sources

PubMedDate not supplied

Chemically modified and unmodified anti-D (Rho) reagents in the micro Du procedure.

The ability of anti-D (Rho) reagents containing chemically modified and unmodified IgG molecules to detect fetal-maternal hemorrhages was compared using mixtures of Rh negative adult red blood cells and Rh positive cord red blood cells. No significant differences among reagents were observed in this small study. These results do confirm the reported lack of sensitivity of the micro Du method as a fetal red blood cell screening test.

Antibodies, Anti-Idiotypic↗

PubMedDate not supplied

Facial muscle reinnervation: a comparison of neuromuscular pedicle with direct nerve implant.

Two methods of reinnervation, the neuromuscular pedicle (NMP) and the nerve implant (NI), were compared in a model using the rabbit's denervated mentalis muscle. Results from evoked electromyographic (EMG) and muscle tension studies (twitch and tetanic contraction) provided the basis of comparison. In addition, the timing of denervation was studied (ie, at the time of implantation of the NMP or NI, or 2 weeks following implantation). The NMP achieved more rapid reinnervation and produced stronger contractions than the NI. Demonstrable reinnervation with an NMP was accelerated when the implantation occurred prior to the denervation. This was not the case with the NI. There was poor correlation between the evoked EMG potential and the strength of both twitch and tetanic contraction. It was concluded on the basis of this study that muscle tension provided a more accurate means of assessing reinnervated muscle function. Of the two methods, the NMP would seem, therefore, to be the technique of choice when it is available. The NI is certainly effective and should be used when a satisfactory NMP is not available.

Animals↗

PubMedDate not supplied

Experimental cryptorchidism protects against long-term 2,5-hexanedione-induced testicular germ cell loss in the rat.

Male infertility is a common side effect of aggressive cancer chemotherapy. One possible approach to decreasing gonadal injury in this setting is the production of artificial cryptorchidism (elevating the testes into the inguinal canal) to produce reversible germ cell loss and cytoprotective hemodynamic changes in the testes. This approach to preserving male germ cell production was explored in a rat model combining experimental cryptorchidism and 2,5-hexanedione intoxication. Rats were protected from irreversible germ cell loss produced by 2,5-hexanedione only when the testes were cryptorchid during the time of intoxication. Sham-operated rats and rats made cryptorchid following intoxication were not protected from 2,5-hexanedione-induced testicular germ cell loss. Decreased delivery of the toxic agent to the cryptorchid testis is the likely explanation of the protective effect.

Animals↗

PubMedDate not supplied

2,5-hexanedione exposure in the rat results in long-term testicular atrophy despite the presence of residual spermatogonia.

Charles River CD rats (approximate weight, 208 g) were exposed to 1.0% 2,5-hexanedione (2,5-HD) in drinking water for 5 weeks. Rats were killed 27, 60, and 75 weeks after exposure to evaluate the recovery potential following testicular injury. At 27 weeks, normal serum testosterone and significantly elevated serum luteinizing hormone and serum follicle-stimulating hormone levels were found in treated rats. The 2,5-HD-treated rats had low testicular and epididymal weights at all time points (28% and 72% of controls, respectively, at 75 weeks). Microscopically, there was a generalized loss of postspermatogonial germ cells at all time points, with no seminiferous tubules exhibiting normal spermatogenesis at 75 weeks. However, a relatively constant population of 3.1 to 3.7 spermatogonia/100 Sertoli cells was found in atrophic seminiferous tubules at all time points. The presence of a constant residual population of type A spermatogonia without a normal mass of more mature germ cells and the observed hormonal alterations suggest that 2,5-HD intoxication produced a lengthy disruption in local testicular homeostatic mechanisms that control spermatogenesis.

Animals↗

PubMedDate not supplied

Dystocia in nine British breeds of cattle and its relationship to the dimensions of the dam and calf.

The degree of assistance provided at 1353 calvings from 954 heifers and cows of nine breeds of British cattle (Ayrshire, British White, Dexter, Friesian/Holstein type, Gloucester, Kerry, Longhorn, Shetland and White Park) was recorded and analysed in terms of the dimensions of the dam and the calf. The sires had been chosen in accordance with normal farming practice. A heavy calf did not lead to dystocia. Assistance at calving was most frequently provided in the Ayrshire herd, which was used for veterinary teaching. There were very few difficult calvings in the seven rare breeds, but this was as likely to have been due to management policy as to the breed characteristics. A large tuber coxae measurement was associated with ease of calving, particularly in the Dexter. The breeds showed a wide range of pelvic dimensions and therefore provide a source of genetic variation.

Animals↗

PubMedDate not supplied

Development and characterization of a prepubertal rat Sertoli cell line, 93RS2.

Sertoli cells in the seminiferous epithelium provide both structural and nutritional support to germ cells during spermatogenesis. Primary Sertoli cells in culture are an effective tool for the in vitro study of Sertoli cell function; however, primary cultures are inherently variable, time consuming to prepare, expensive, and wasteful of animals. We therefore developed a Sertoli cell line, called 93RS2, by immortalizing primary Sertoli cells derived from prepubertal rats with SV40 tsA255. This cell line proliferates at the permissive temperature (32 degrees C) and has enhanced expression of a differentiated Sertoli cell phenotype at the nonpermissive temperature (40-41 degrees C). Cytogenetic analysis demonstrated that 93RS2 has 42 chromosomes per cell, the same as a normal rat. mRNA analysis showed that this cell line, when cultured at a nonpermissive temperature, exhibited increased expression of transferrin in the presence of testosterone and enhanced expression of sulfated glycoprotein-2. A tumorigenicity assay showed that 93RS2 cells were temperature-dependent for growth in soft agar and were capable of forming tumors in nude mice. In conclusion, this rat 93RS2 cell line should be useful for the study of Sertoli cell function.

Animals↗

PubMedDate not supplied

Local inflammatory response and vector spread after direct intraprostatic injection of a recombinant adenovirus containing the herpes simplex virus thymidine kinase gene and ganciclovir therapy in mice.

We have evaluated the safety and potential toxicity of an adenoviral vector containing the herpes simplex virus thymidine kinase gene (adenovirus/Rous sarcoma virus thymidine kinase in a preclinical model for prostate cancer. Clinical grade vector prepared for human trials was injected directly into the dorsolateral prostate of C57Bl/6 mice in a volume of 5 microL at doses of 2.5 x 10(6), 2.5 x 10(7), or 2.5 x 10(8). The mice received intraperitoneal injections of either ganciclovir or saline twice daily for 6 days, beginning 12 hours after vector injection. Representative tissues and fluids were collected for evaluation the day after the final dose. Microscopic pathologic evaluation revealed inflammatory infiltration without necrosis within the dorsolateral and ventral prostate, but no necrosis or leukocyte infiltration was observed in sample tissues from lung, liver, large intestine, bladder, seminal vesicle, testis, or epididymis. DNA was extracted from the above tissues as well as pelvic lymph nodes, blood, seminal fluid, urine, and sperm and analyzed by polymerase chain reaction for the presence of vector sequences. The vector was readily detected in the dorsolateral prostate, the site of injection. The amount of vector detected was reduced in some samples from ganciclovir-treated animals. At the highest dose, vector spread was observed in the ventral prostate, seminal vesicle, testis, pelvic lymph nodes, gut, and liver. Spread to the testis was observed in only one animal. Vector DNA was not detected in urine, seminal fluid, or sperm but was detected in the blood of one animal. This adenoviral vector, therefore, appears to have minimal spread to sites distant from the site of injection and no detectable pathological sequelae within this dose range in this preclinical model for prostate cancer, which may be generalizable to other solid tumors.

Adenoviridae↗