Chemically induced Parkinson's disease: intermediates in the oxidation of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine to the 1-methyl-4-phenyl-pyridinium ion

Various unstable intermediate oxidation states have been postulated in the metabolic activation of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine to the 1-methyl-4-phenyl pyridinium ion. We now report the first direct observation of these free radical intermediates by pulse radiolysis and flash photolysis. Studies are described of various reactions of such species, in particular with dopamine whose autoxidation to dopamine quinone is reported to be potentiated by 1-methyl-4-phenyl-1,2,3, 6-tetrahydropyridine.     

Epidermal cellular proliferation and differentiation in sexually mature male Salmo salar with androgen levels depressed by oil

Sexually mature male Salmo salar exhibit epidermal thickening and an increase in goblet cell concentration during the spawning season. The ventral skin, which is likely to experience most abrasive contact during the spawning period, has the thickest epidermis and the greatest goblet cell concentration. Following exposure to crude oil there is inhibition of cellular proliferation and elongation associated with epidermal thickening, and also inhibition of mucigenesis. Data on the androgen levels in these fish, and data from earlier studies involving treatment with hormones, indicate that oil-related epidermal effects during the spawning period are most likely systemic in origin, probably arising from reduced plasmatic androgen levels.     

Thermal Denaturation of Native Striatal Tyrosine Hydroxylase: Increased Thermolability of the Phosphorylated Form of the Enzyme

Tyrosine hydroxylase was purified from bovine corpus striatum. The native enzyme had a half-life of 15 +/- 3 min at 50 degrees C. Phosphorylation of tyrosine hydroxylase with protein kinase purified from both corpus striatum and heart activated the enzyme, but activity was rapidly lost with additional preincubation of the enzyme at 30 degrees C. Thermal denaturation studies indicated that phosphorylated tyrosine hydroxylase had a half-life of 5 +/- 2 min at 50 degrees C     

Effect of neurotensin on pancreatic function in man

The effect of neurotensin on submaximally-stimulated hepatobiliary and pancreatic secretion was studied in 6 healthy subjects. An intravenous infusion of neurotensin 1.4 ± 0.3 pmol/kg/min, designed to reproduce plasma neurotensin immunoreactivity levels within the physiological range, produced a significant increase in pancreatic bicarbonate output. Plasma concentrations of pancreatic polypeptide rose by 83 ± 16 pmol/l and were associated with a small reduction in trypsin, but no significant change in bilirubin outputs.     

Energy transfer between the carotenoid and the bacteriochlorophyll within the B-800-850 light-harvesting pigment-protein complex of Rhodopseudomonas sphaeroides

Energy transfer between carotenoid and bacteriochlorophyll has been studied in isolated B-800-850 antenna pigment-protein complexes from different strains of Rhodopseudomonas sphaeroides which contain different types of carotenoid. Singlet-singlet energy transfer from the carotenoid to the bacteriochlorophyll is efficient (75-100%) and is rather insensitive to carotenoid type, over the range of carotenoids tested. The yield of carotenoid triplets is low (2-15%) but this arises from a low yield of bacteriochlorophyll triplet formation rather than from an inefficient triplet-triplet exchange reaction. The rate of the triplet-triplet exchange reaction between the bacteriochlorophyll and the carotenoid is fast (Ktt greater than or equal to 1.4 . 10(8) S-1) and also relatively independent of the type of carotenoid present.     

Boric Acid Poisoning: Report of 11 Cases

Boric acid poisoning in 11 infants, occurring in the newborn nursery as a result of the accidental and inadvertent use of 2.5% boric acid in the preparation of the formulae, is reported. Five of the infants died. All except two exhibited the classical symptomatology of acute boric acid poisoning, namely, diarrhea, vomiting, erythema, exfoliation, desquamation of the skin, and marked central nervous system irritation. Early manifestations of poisoning were nonspecific, and one patient died before skin manifestations were noted. Peritoneal dialysis, instituted in nine cases, was found to be the most effective method of treatment. It is recommended that boric acid, which is of doubtful therapeutic value, should be completely removed from hospitals, dispensaries and pharmacopoeias.     

Effect of Metalaxyl on the incidence and severity of Pearl millet downy mildew disease in Northern Nigeria

Pearl millet downy mildew (DM) incidence, severity and yield losses of two pearl millet varieties (local and improved) due to the disease were determined in the field. Significant differences in the disease incidence and severity were recorded in the plots sown with metalaxyl-treated seeds and those sown with non-treated seeds, indicating the efficacy of the fungicide on the fungus. Yield losses due to non-treatment of seeds with metalaxyl was 40.88 and 45.39% in a local variety and 43.00 and 18.60% in an improved variety in the 2000 and 2001 cropping seasons respectively. Significant differences between plots sown with metalaxyl-treated and those sown with non-treated seeds were obtained for other yield components such as 1000-grains weight, panicle length and weight.