Search PubMed⌕ Search

Biomedical subjects

A Sidorowicz

Publications and source records attributed to A Sidorowicz.

13 recordsLinked to original sources
PubMed1997

Influence of endogenous cholinergic tone and growth hormone-releasing peptide-6 on exercise induced growth hormone release.

OBJECTIVE: The neuroendocrine mechanisms of exercise-induced GH release remain incompletely understood. In this study we have investigated the influence of endogenous cholinergic tone and growth hormone-releasing peptide-6 (GHRP-6) on exercise induced GH release. DESIGN: Analysis of responses of serum GH to administration of pyridostigmine (PD, 120 mg, orally) or GHRP-6 (100 micrograms, i.v.), to exercise alone, and to the combinations of PD plus exercise or GHRP-6 plus exercise. An indirect estimation of the secretory pattern of GH was calculated by the deconvolution technique. Exercise was performed on a bicycle ergometer with a 20-minute workload near the individual lactate threshold of 4 mmol/l. The five tests were performed in random order after an overnight fast, and at least 3 days apart. SUBJECTS: Eleven healthy, non-obese male subjects (age 23.9 +/- 0.3 years, body mass index 23 +/- 0.7 kg/m2, VO2 max: 52.4 +/- 2.0 ml/min/kg body weight; mean +/- SEM) participated in this study. MEASUREMENTS: Serial blood samples from an indwelling catheter were taken before, during and after exercise for analysis of GH (IRMA), lactate (YSI 2300) and haematocrit (micromethod). RESULTS: Irrespective of the tests, peak values of GH were found between the 18th and 26th minute. The secretory pattern showed differences between the tests. Exercise alone induced relatively short lasting peaks of medium amplitude, whereas PD induced long lasting peaks with low amplitudes. PD plus exercise showed additive effects on the amplitude of GH peaks. GHRP-6 induced long lasting peaks with high amplitude, and GHRP-6 plus exercise also had additive effects on the amplitude. CONCLUSIONS: The increase in frequency and amplitude of GH peaks, which occurred during the GHRP-6 plus exercise, indicates that exercise-induced GH release is not mediated through an increment in the release of an endogenous GHRP-6-like ligand, favouring the possibility that exercise-induced GH release is mediated through an increase in endogenous GHRH release.

Adult↗
PubMed1996

Perimenopausal obesity.

In recent years perimenopausal obesity has attracted much attention, because it affects as many as 60% of women of menopausal age. The severe clinical implications of obesity directed our efforts to establish etiological factors and possible ways of treatment. It is clear that there are numerous conditions that underly perimenopausal obesity. Among these, genetic factors, neuropeptides, adrenergic nervous system activity and hormones play a role. Reproductive hormones are also an important factor, but their influence on adipose tissue is only indirect because there are no receptors for sex steroids in fatty tissue. Reports of hormone replacement therapy in women of postmenopausal age have come to different conclusions, so its influence on the etiology of perimenopausal obesity cannot be completely excluded. However, the potential benefit of this kind of treatment in female patients at menopausal age must always be considered.

Dehydroepiandrosterone↗
PubMed1990

Effect of NAD coenzyme on the inactivation of glyceraldehyde-3-phosphate dehydrogenase by anionic phospholipids.

The inactivation of bovine heart glyceraldehyde-3-phosphate dehydrogenase by phosphatidylinositol (PI) and phosphatidylserine (PS) in the form of liposomes was investigated in the presence and absence of NAD excess. In the absence of NAD, the enzyme activity decreased to about 50% of its initial value at 0.6 mM PI and 0.8 mM PS (lipid-to-protein molar ratio 600 and 800, respectively). In the same lipid concentration range almost full regainment of the activity was observed in the presence of 80 microM NAD. It was shown that the excess of NAD protects the enzyme against conformational change induced by the phospholipids. Centrifugation experiments showed that both PI and PS bind significant amounts of NAD.

Animals↗
PubMed1986

Comparative study of the structure of glyceraldehyde-3-phosphate dehydrogenase from bovine heart muscle.

Glyceraldehyde-3-phosphate dehydrogenase with a specific activity of 153 units/mg protein was isolated from bovine heart muscle. Its relative molecular mass was found to be 144,000. The tryptic peptide map and amino acid analysis were obtained. The N-terminal sequence was established as Val-Lys-Val-Gly-Val-Asn-Gly-... and C-terminal as ...-Ala-Ser-Lys-Glu. Fluorescence and optimal rotation dispersion measurements were performed. The data were compared with other glyceraldehyde-3-phosphate dehydrogenases.

Amino Acid Sequence↗
PubMed1986

Interaction of phosphoglycerate kinase with phosphatidylserine liposomes.

The interaction of 3-phosphoglycerate kinase from bovine heart with natural phosphatidylserine (I) and synthetic dipalmitoyl phosphatidylserine (II) in form of liposomes was investigated by measuring fluorescence and activity of the enzyme. The addition of increasing amounts of I resulted in progressive quenching of protein fluorescence with no shift in the emission maximum. In contrast, II did not cause any change in the fluorescence. In the presence of low amounts of I and II (lipid/protein molar ratio 10-40) full enzymatic activity of 3-phosphoglycerate kinase was observed even after 80 min of incubation, whereas without phospholipids the activity considerably decreased. At higher lipid concentrations I strongly inactivated the enzyme and the inactivation by II was only insignificant. It was concluded that the phospholipid membrane protects the enzyme against thermal denaturation, whereas the inactivation is mainly due to phospholipid impurities.

Liposomes↗
PubMed1984

Growth rate of the bacterium Sphaerotilus natans in lead-containing medium and the effect of calcium ions.

Growth rate of bacteria Sphaerotilus natans in lead-containing medium (1 X 10(-4) M Pb2+) and bioaccumulation of lead in the bacterial cells were investigated together with the effect of calcium ions on these processes. A rapid increase in biomass was observed in the presence of calcium and lead whereas calcium alone had no visible effect on the bacterial growth. The increase in biomass in the presence of lead and calcium was accompanied by a pronounced drop in lead content in the bacterial cells. This suggests that calcium ions protect the bacterial cells against lead poisoning.

Cadmium↗
PubMed1980

Bacterial sensitivity test kit.

A method and an apparatus have been developed for the determination of the susceptibility of pathogenic bacteria to antibiotics. The method has the same applicability as the accepted Bauer-Kirby method. The method is rapid, the procedure for the performance of the test is simple, the supplies and equipment for the performance of the test are inexpensive and finally the test gives easily measurable end-points. The correlation of the method to the accepted Bauer-Kirby method against clinical isolates of gram-positive bacteria was 90-100% for the antibiotics tested with the exception of neomycin which was 80%. With gram-negative bacteria, the correlation was 92-100% for the antibiotics tested.

Humans↗
PubMed1979

Disinfection of anesthesia and respiratory therapy equipment with acid glutaraldehyde solution.

The dilution of acid glutaraldehyde solution and its effect on microbiological effectiveness were investigated using Sonacide and the Cidematic Decontamination System under normal use conditons at 18 hospitals over a 4-week period. The dilution of Sonacide was found to follow first-order kinetics and is described by the equation, ln C = ln Co-KT, where K is the apparent dilution-rate constant. The average dilution-rate constant under normal use conditions was 0.015/day. It takes an average of 47 days under normal hospital-use conditions to reduce its potency to half its original strength. The average glutaraldehyde concentration after 28 days' use was found to be approximately 66% of the initial concentration. The AOAC use-dilution test was employed to evaluate the microbiological effectiveness of the Sonacide samples collected weekly for four weeks. Results showed that all the Sonacide samples from 18 hospitals passed the AOAC use-dilution test for Pseudomonas aeruginosa (ATCC 15442). Based on this study, it is apparent that Sonacide can be used to disinfect various anesthesia and respiratory therapy equipment for up to 4 weeks in the Cidematic machine.

Aldehydes↗
PubMed1978

Rapamycin (AY-22,989), a new antifungal antibiotic. III. In vitro and in vivo evaluation.

The activity of rapamycin, a new anti-Candida antibiotic, was not affected by pH values between 6 and 8; at pH 4, however, activity was abolished. The MIC of rapamycin did not vary drastically with the size of inoculum: a ten-fold dilution of the inoculum reduced the MIC only two-fold. Serum binding was extensive. Serum levels obtained in mice were higher on subcutaneous injection than with oral administration. Dogs absorbed rapamycin after oral administration. Rapamycin cured systemic candidosis in mice: PD50 s.c. was 9.5 mg/kg: PD50 p.o. was 11 mg/kg. In the same experimental infections amphotericin B and nystatin exhibited PD50 values of less than 0.25 mg and greater than 4,000 units/kg respectively. Rapamycin and amphotericin B, administered at 1, 4 and 24 hours after infection, gave approximately the same percent survival after 30 days of observation. When the above treatment was extended by an additional daily treatment for 6 days, rapamycin by the subcutaneous route yielded a higher percentage of survival than either rapamycin or amphotericin B, administered orally, after a 30-day observation period. Vaginal candidosis in female rats was treated efficiently (91% cure) by rapamycin administered orally. No increase of resistance of C. albicans was observed during treatment.

Amphotericin B↗
PubMed1975

Naphthyridinomycin, a new broad-spectrum antibiotic.

A new antibiotic, naphthyridinomycin, was isolated in crystalline form from the culture filtrate of Streptomyces lusitanus AY B-1026. The antibiotic is active against a large number of both gram-positive and gram-negative bacteria, and inactive against Candida albicans, Trichophyton granulosum and Microsporum gypseum. The antibiotic is toxic in mice.

Animals↗