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Biomedical subjects

T D Glover

Publications and source records attributed to T D Glover.

At least 19 recordsLinked to original sources
PubMed1997

Surgery for cataracts.

The advent of phacoemulsification has substantially improved the success rate of cataract surgery in dogs, whereas the development of artificial lens implantation has equally improved postoperative visual acuity. In this chapter information pertaining to the etiology, diagnosis, and management of canine cataracts is provided for the general practitioner. More detailed information on phacoemulsification and artificial lens implantation is provided for residents in training or practicing ophthalmologists that may be converting from extracapsular extraction.

Animals↗
PubMed1984

Effect of scrotal insulation on the pituitary-testicular axis of the ram.

The testes of rams were insulated for 28 days. After 28 days typical degenerative changes occurred in the tubular compartment of the testis. Spermatozoa, spermatids and, in many tubules, spermatocytes were absent. A pronounced dilatation of the testicular lymph vessels was noted, and a morphometric study indicated that the volume fraction occupied by Leydig cells was greater than in controls. A serial bleeding regimen showed that peripheral plasma concentrations of FSH were elevated and of testosterone were usually reduced after scrotal insulation. Although mean testosterone levels were unchanged after 7 days of treatment, there were more hormone episodes, each of significantly reduced amplitude. LH values were elevated at this time and there was an increase in the number and amplitude of LH episodes. After 14 days of scrotal insulation, mean and basal levels of testosterone were significantly reduced, and episodes of secretion were much smaller in amplitude. Mean LH values were elevated and each secretory episode was of significantly greater amplitude than in control blood. These results show that the testes of scrotally insulated rams are relatively insensitive to endogenous LH and that this treatment affects cells within the seminiferous tubule and those in the interstitial compartment.

Animals↗
PubMed1983

Seasonal and circadian changes of testosterone levels in the peripheral blood plasma of stallions and their relation to semen quality.

Three stallions were bled each hour for 25 h at 28-day intervals throughout 1 year. Testosterone levels were pulsatile. Pulse frequency and pulse amplitude were higher in the summer months than at other times (P less than 0.01). The number of testosterone pulses also varied throughout the day, with the greatest frequency occurring in the afternoon (14.00-17.00 h) and at night (22.00-01.00 h). Mean testosterone levels were highest in the summer (P less than 0.01) but showed a secondary, smaller increase in the autumn. Semen characteristics were assessed from measurements of 222 stallions. Semen volume was greatest in the summer (P less than 0.01) but both the concentration (P less than 0.01) and the total number of spermatozoa per ejaculate (P less than 0.05) were highest in the autumn. These results show that the highest testosterone concentrations in peripheral plasma are not necessarily associated temporally with optimum semen quality.

Animals↗
PubMed1978

Effects of duct ligation and orchidectomy on histochemical reactions in the hamster epididymis.

The epididymis was ligated at the efferent ductules and at the middle segment. Histochemical changes occurred only proximal to the ligature. Orchidectomy caused progressive changes, mostly reversible by testosterone treatment throughout the epididymis. It is concluded that the integrity of the initial segment is dependent upon androgen reaching it via the testicular fluid.

Animals↗
PubMed1977

Some effects of cyproterone and cyproterone acetate on the reproductive physiology of the male rat.

Male rats were treated with 5 or 20 mg cyproterone acetate/kg/day or 20 mg cyproterone/rat/day for 1, 2, 3, 4, or 5 weeks. There was some reduction in fertility with both compounds, the maximum effect occurring after 5 weeks with the higher dose of cyproterone acetate and after 2 weeks with cyproterone. A significant increase in testosterone levels was found after treatment with the high dose of cyproterone acetate by 1 week and with cyproterone by 2 weeks. Dose-dependent atrophy of the seminal vesicles occurred after treatment with cyproterone acetate; with cyproterone atrophy occurred at 1 and 2 weeks but approximated to control values at 3, 4 and 5 weeks. Epididymal weights were reduced with the high dose of cyproterone acetate but the low dose had little effect. Reduction in the weight of the testes was only observed after 5 weeks of treatment with the high dose of cyproterone acetate. Since plasma testosterone levels were not depressed below normal values, accessory sex organ regression evidently resulted from the local antiandrogenic action of the drugs. There was some indication of interference with the secretory and absorptive activity of the lining cells of the epididymis but in general treatment with either steroid caused only relatively small and variable changes in the composition of epididymal plasma.

Animals↗
PubMed1975

The effects of alpha-chlorohydrin on the composition of rat and rabbit epididymal plasma: a possible explanation of species difference.

The relationship between the antifertility effect of alpha-chlorohydrin and changes in composition of luminal plasma from the cauda epididymidis of rats and rabbits has been investigated. At each dose regimen studied, the fertilizing capacity of rats treated with alpha-chlorohydrin was reduced to zero. The levels of sodium, potassium, glycerylphosphorylcholine (GPC), acid phosphatase and alkaline phosphatase in epididymal plasma were not markedly affected by drug treatment. The most noticeable change was a considerable increase in the concentration of lactic dehydrogenase (LDH) at all dose levels and of glutamic-oxaloacetic transaminase (GOT) after 7 days of treatment with 8 and 16 mg/kg. The effect of cold shock on the composition of epididymal plasma showed that LDH and GOT are, at least in part, derived from spermatozoa. In contrast, alpha-chlorohydrin did not have an antifertility action in the rabbit, and the only notable change in the compositon of epididymal plasma was an increase in the level of GPC. These results provide evidence that, in the rat, alpha-chlorohydrin or a metabolite primarily exerts its antifertility effect by a direct action on the spermatozoa, whilst in the rabbit a barrier may exist to the entrance of the drug into the lumen of the epididymal duct.

Acid Phosphatase↗