Phenytoin as a novel anti-vitiligo weapon

Vitiligo is a psychologically devastating clinical conundrum which affects approximately 1% of the general population. The exact cause of the illness is an enigma, but several hypotheses about its pathogenesis are advanced.The autoimmune hypothesis proposes an autoimmune attack against melanocytes. Although anti-melanocyte autoantibodies have been demonstrated in vitiligo, recent research casts doubt on their pathogenic role and instead supports the involvement of cell-mediated autoimmune response in the pathobiology of this disorder, which is characterized by increase of suppressor T-cells and decrease of the helper/suppressor ratio in association with the presence of type-1 cytokine secreting cytotoxic T cells in the vicinity of disappearing melanocytes.The neural hypothesis proposes that increased release of norepinephrine, a melanocytotoxin, from the autonomic nerve endings in the microenvironment of melanocytes injures these cells. Moreover, norepinephrine induces the catecholamine degrading enzyme monoamine oxidase (MAO), which favors the formation of toxic levels of hydrogen peroxide in the vicinity of melanocytes.Another theory suggests that abnormal permeability of melanosome membrane, which normally prevents the diffusion of toxic melanin precursors into the cytoplasm, may cause melanocyte damage.Phenytoin, the widely-used anticonvulsant, has been employed both topically and systemically in the treatment of some dermatological disorders. The drug has been shown to significantly suppress mitogen-induced activation of lymphocytes and cytotoxic T lymphocyte activity and to polarize the immune response toward the type-2 pathway. It also significantly decreases suppressor T cells and increases the helper/suppressor ratio.At high concentrations, the drug inhibits the release of norepinephrine and the activity of MAO. Moreover, phenytoin is suggested to interact with membrane lipids, which may promote stabilization of the membranes.The hydantoin moiety of phenytoin exerts a direct stimulatory action on melanocytes; facial hyperpigmentation is a recognized side effect of orally administered phenytoin.Altogether, the above evidence suggests that phenytoin could be therapeutically effective against vitiligo. As phenytoin stimulates collagen production and inhibits its breakdown, its concomitant use with topical steroids could prevent steroid-induced skin atrophy while potentiating the anti-vitiligo effect of these agents.     

Fertility of sows mated on different days of the week

The farrowing rates resulting from matings on different days of the week were determined for a 2800-sow intensive piggery in both 1983 and 1984. The results showed that sows mated early in the week achieved a significantly higher farrowing rate than sows mated late in the week (P less than 0.0001). During the seasonal (summer to autumn) infertility period, Wednesday matings resulted in a poor farrowing rate whereas for the rest of the year farrowing rates following Wednesday matings were similar to those for Sunday Monday and Tuesday matings. Consistent results were obtained for data from both years. It is proposed that the stress of regrouping unmated sows on Wednesday to accommodate newly weaned sows is responsible for this decrease in fertility. This study illustrates how detailed analysis of farrowing rates on a day of mating basis can identify a problem which is otherwise masked by weekly data.     

Activity of the ovarian follicle system in cows with various puerperal courses

The presence of the various categories of follicles (less than 0.05; 0.5-1.0; 1.0-1.5; less than 1.5 cm) in the ovaries was examined by palpation, endoscopically and post mortem in cows with a physiological puerperium (n = 5), with puerperal endometritis (n = 5), and with retention of afterbirth (RS, n = 5) from the second to the 20th day post partum (p.p.). The largest proportion (82.6%) of the smallest follicles (less than 0.5 cm) was recorded between the fourth and seventh day p.p. in clinically healthy cows; a marked decrease was then observed until the 15th day p.p. In cows with endometritis the proportion of the smallest follicles was only 60%. The average number of follicles 0.5 to 1.0 cm in size increased 1.6 times in the healthy cows between the 7th and 15th day p.p., but in cows with pathological puerperium their number declined. The largest follicles (greater than 1.5 cm) occurred in the cows with pathological puerperium as late as at the end of the period of study, whereas in healthy cows their occurrence was fairly frequent sooner--between the 8th and 11th day p.p. In all groups of cows the average number of follicles of all size groups declined until the 12th day p.p. which is an indication of the finished first growth wave. Occurrence of the first follicle larger than 1 cm in diameter was observed in 73.3% of cases in the contralateral ovary, opposite to the originally gravid uterine horn. It is assumed that delayed and asynchronous growth of follicles in cows with pathological puerperium is a consequence of disturbed repairing processes of endometrium and of endocrine dysfunction.     

Improved feed intake and body weight change in sheep treated with dexamethasone at entry into pens or feedlots

Treatment with the synthetic glucocorticoid dexamethasone sodium phosphate increased the feed intake of sheep within 24 h. A single treatment with the longer-acting compound dexamethasone trimethylacetate had a slower effect, but resulted in improved feed intake and enhanced body weight gain over a period of 7 to 14 days. Treatment was effective in sheep housed individually and in sheep penned in groups. The improvement in body weight gain disappeared 15 to 20 days after a single treatment, but in most studies treated sheep had less variability in weight change than untreated sheep at this time. A statistically significant increase in body weight gain was observed in 8 of 11 trials; in the other 3 trials, it appeared that the feed intake of the untreated sheep was already maximal. Wethers treated with dexamethasone trimethylacetate on arrival at an assembly point for live export arrived in the Middle East 23 days later with a lower mean weight loss, partly because fewer sheep lost a significant amount of weight.     

Haematuria in two geldings caused by osteochondroma of the os pubis: Case reports and anatomic study of the os pubis in 41 cadaveric pelvises

Exostosis of the os pubis causing haematuria, and potentially cystorrhexis, in horses has not been described in the literature. In this study, 2 geldings that suffered from exercise‐induced haematuria caused by an osteochondroma of the os pubis, and the assessment of 41 cadaveric pubic bones are reported on. The anatomy of the os pubis is highly variable. The prevalence of exostosis in the os pubis appears to be higher in male horses. Palpation and ultrasonography of the pelvis per rectum and cystoscopy are valuable diagnostic tools. Depending on the extent of changes in the bladder wall, surgical removal of the exostosis should be considered in order to prevent cystorrhexis. In horses that present with haematuria, closer assessment of the os pubis for the presence of an exostosis is warranted.