Changes in intra-abdominal visceral fat and serum leptin levels in patients with obstructive sleep apnea syndrome following nasal continuous positive airway pressure therapy.

BACKGROUND: Obstructive sleep apnea syndrome (OSAS) is a common disorder in obese subjects. Visceral fat accumulation (VFA) is a better predictor of coronary heart disease than body mass index. Leptin is a hormone involved in the control of body weight and fat distribution. The effect of nasal continuous positive airway pressure (NCPAP) treatment on VFA and serum leptin levels in OSAS patients has not been known. METHODS AND RESULTS: VFA and subcutaneous fat accumulation (SFA) were assessed by CT before and after NCPAP treatment in 22 OSAS patients (mean apnea and hypopnea index >50 episodes/h). Serum leptin levels of another 21 OSAS patients were measured before and after 3 to 4 days of NCPAP to gain insight into the mechanism by which NCPAP affects fat distribution. VFA and SFA decreased significantly after 6 months of NCPAP treatment (236+/-16 to 182+/-14cm(2), P=0.0003 and 215+/-21 to 189+/-18 cm(2), P=0.003, respectively). VFA decreased significantly in the body weight reduction group (n=9, P<0.01) and the no body weight reduction group (n=13, P<0.03). In contrast, SFA changed significantly in the body weight reduction group only (P<0.01). Leptin levels decreased significantly following 3 to 4 days of NCPAP (P<0.01), whereas body weight, fasting insulin, and cortisol levels did not change significantly. CONCLUSIONS: Correction of sleep disordered breathing by NCPAP may be used to reduce VFA in OSAS patients. OSAS may have significant effects on the serum leptin levels.

Analyses of metal ions in spider venoms in relation to insecticidal activity of clavamine.

To elucidate insecticidal activity of spider toxins, metal ions in venoms and in the bodies were determined by thin layer chromatography, spark source mass spectrometry, ion chromatography, inductively coupled plasma emission spectrometry and atomic absorption spectrometry. Two kinds of spiders were used, Nephila clavata and Nephila maculata. Metals from their venom glands were extracted with hydrochloric acid and the metal concentrations were almost the same in the two species. Many kinds of metals, Fe, Zn, Pb, Cu, Ca, Mg, Na, P and S were found at higher levels in the venoms at concentrations higher than in the bodies. The contents of metal ions were low in the dragonfly and the cicada which are considered to be preys. Clavamine, the main insecticidal component in N. clavata, was effective on larvae of a mosquito with Ca2+, Fe3+ or Pb2+, but ineffective with Mg2+, Zn2+, Fe2+ or Cu2+. It is suggested that the metal chelates play an important role in the intoxication and detoxication of the spider toxins.

Color development upon reaction of ferric ion with the toxin JSTX, a glutamate receptor blocker present in the venom gland of the spider Nephila clavata (Joro spider).

A spider toxin, JSTX, derived from Nephila clavata, which blocks glutamate receptor was found to react with Fe3+. Mechanism of the coloration may be chelate formation since the green color completely faded upon the addition of EDTA. The colored JSTX significantly lost its neurophysiological activity. This unique coloration may be useful for not only detecting specific blockers of the glutamate receptor in spider venom but also for characterizing the glutamate receptor.

Reductive metabolism of aromatic nitro compounds including carcinogens by rabbit liver preparations.

Reductive metabolism of aromatic nitro compounds was examined with rabbit liver preparations. Under anaerobic conditions, carcinogenic 2-nitrofluorene, 4-nitrobiphenyl, and 1-nitro-naphthalene were reduced to the corresponding hydroxylamines and amines, whereas the carcinogenic 1-nitropyrene was reduced only to the corresponding amine by liver cytosol in the presence of 2-hydroxypyrimidine, an electron donor of aldehyde oxidase. These metabolites were identified unequivocally by comparing their mass spectra and thin-layer chromatographic behaviors with those of the authentic samples. Both liver microsomes and cytosol catalyzed the reduction of these aromatic nitro compounds in varying degrees. The microsomes required reduced pyridine nucleotides for occurrence of the nitroreductase activities. In this case, reduced nicotinamide adenine dinucleotide phosphate was more effective than reduced nicotinamide adenine dinucleotide as an electron donor. The cytosol by itself exhibited some nitroreductase activities, which were markedly enhanced by addition of an electron donor of aldehyde oxidase, i.e., N1-methylnicotinamide or 2-hydroxypyrimidine. The full activities of the cytosol with the electron donor were much higher than those of the microsomes with the reduced pyridine nucleotide. Purified liver aldehyde oxidase, like the cytosol, exhibited significant nitroreductase activities in the presence of its electron donor. These results indicated that cytosolic aldehyde oxidase functions as a major enzyme responsible for the reduction of aromatic nitro compounds including carcinogens in rabbit liver.

A comparative study on 1-nitropyrene and nitrofurazone reductases in Escherichia coli.

1-Nitropyrene and nitrofurazone reductases in Escherichia coli B/r were studied comparatively. Nitrofurazone reductase activity was oxygen-insensitive, whereas 1-nitropyrene reductase activity was markedly inhibited by oxygen in both intact cells and cell-free preparations. The former activity depended upon reduced nicotinamide adenine dinucleotide or reduced nicotinamide adenine dinucleotide phosphate, whereas the latter activity upon flavin-adenine dinucleotide (FAD) as well as the reduced pyridine nucleotide. E. coli B/r acquired resistance to nitrofurazone in two mutational steps, associated with stepwise loss of the oxygen-insensitive nitrofuran reductase activity. However, 1-nitropyrene reductases were not affected at all by the mutation. These facts indicated that the major enzymes responsible for the reduction of 1-nitropyrene and nitrofurazone in E. coli B/r were different from each other. 1-Nitropyrene reductases were resolved by diethylaminoethyl-cellulose column chromatography into four enzymes all of which seem to reduce FAD, too. Among them, three enzymes appear to be able also to catalyze the reduction of nitrofurazone under anaerobic conditions.

Studies on bacterial nitroreductases. Enzymes involved in reduction of aromatic nitro compounds in Escherichia coli.

Enzymes involved in reduction of methyl p-nitrobenzoate in Escherichia coli B/r were oxygen-insensitive and precipitated between 30 and 60% ammonium sulfate saturation from cell-free extracts of the strain. The reductases were resolved by DEAE-cellulose column chromatography into three enzymes, NADH-linked, NAD(P)H-linked and NADPH-linked ones. These enzymes were flavoprotein which could be inactivated by dialysis against 1 M potassium bromide and could be reactivated by FMN. The NADH-linked and NAD(P)H-linked reductases were sensitive to dicumarol and exhibited menadione reductase activities. Aromatic nitro compounds with electron-withdrawing p-substituents were easily reduced by the NAD(P)H-linked reductase.