PubMed Health⌕ Search

Biomedical subjects

H H Kohl

Publications and source records attributed to H H Kohl.

17 recordsLinked to original sources
PubMed1990

Physiological responses to resistance-exercise in athletes self-administering anabolic steroids.

Endocrine and metabolic responses to resistance exercise were compared in 5 athletes self-administering (SL) anabolic steroids and 8 athletes (L) not using these compounds. Exercise consisted of 5 sets of 10 repetitions in the squat and quarter squat. Blood samples were collected before (pre) and immediately after (post) exercise, and following 30 minutes of recovery (post-30). Except for significantly lower lactate concentrations in SL (p less than 0.015) at post-30, the responses to exercise and recovery were similar in both groups. Significantly higher hematocrits (p less than 0.0001), total androgen concentrations (p less than 0.0001), and androgen/cortisol ratios (p less than 0.0001) were observed in the SL group across all time periods. Plasma androgen concentrations increased about 22% in SL following exercise, even though plasma LH concentrations were significantly lower (p less than 0.0001) than in L. Plasma ACTH and cortisol concentrations were not significantly affected. Both groups displayed similar endocrine and metabolic responses to an acute bout of resistance exercise. The higher androgen/cortisol ratios and lower plasma lactate concentrations during recovery are two potential factors which may help explain the lower subjective level of fatigue following training sessions often reported by individuals who use anabolic steroids.

Adrenocorticotropic Hormone↗
PubMed1986

Oxysterols: chemical synthesis, biosynthesis and biological activities.

As a class of compounds, oxysterols have demonstrated a wide variety of biological properties. Due to the general interest in these compounds, new methods of chemical synthesis have been developed to provide them for biological investigation. The specific inhibition by oxysterols of cholesterol biosynthesis in mammalian cells has been shown to result primarily from a decrease in cellular levels of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase activity. Recent evidence suggests these cellular responses may be mediated by an oxysterol binding protein found in the cytosol of many lines of cultured cells. In certain instances, oxysterols have been shown to be produced in biological systems. These results support the supposition that oxysterols may regulate sterol biosynthesis at the cellular level. Included herein are the inhibitory effects of 9 alpha, 11 alpha-epoxycholest-7-en-3 beta-ol cholest-8-en-3 beta-ol-7-one and cholest-8-en-3 beta-ol-11-one on HMG-CoA reductase activity and their relative affinities for a cytosolic binding protein.

Animals↗
PubMed1983

Effects of cis- and trans-platinum complexes on RNA transcription.

Current thinking concerning the anti-cancer actions of platinum complexes view cis-platinum agents as active and trans-complexes as not being anti-neoplastic. It is generally accepted that the active cis forms exert their effects by binding to the DNA template. Data is presented here showing trans-Pt(NH3)2Cl2(trans-PDD) to be much more active than cis-Pt(NH3)2Cl2(cis-PDD) in inhibiting in vitro RNA transcription using both bacterial and eukaryotic enzyme sources. It is further shown that the polymerase enzyme is a much more sensitive target for these platinum agents than the DNA template under the conditions employed.

Animals↗
PubMed1980

Antimicrobial activity of N-chloramine compounds.

Cellular mechanisms of action of two representative N-chloramines were studied. Both compounds, 3-chloro-4,4-dimethyl-2-oxazolidinone (I) and N-chlorosuccinimide (III), inhibited bacterial growth and exerted profound inhibition of bacterial DNA, RNA, and protein synthesis at a concentration of 10(-5) M. Enzymes containing sulfhydryl groups generally were significantly inhibited by these chloramines at 10(-4) M. Dihydrofolate reductase, which contains no sulfhydryl groups, also was inhibited but at much higher chloramine concentrations (10(-2) M); ribonuclease, which also contains no sulfhydryl groups, was unaffected. All of these inhibitory effects of the chloramines could be prevented if sulfhydryl-containing reagents (mercaptoethanol or dithiothreitol) were added before or together with the chloramine. Once inhibition was produced by the chloramine, it was not reversible by later addition of the sulfhydryl reagents. These results suggest that these chloramines act at sulfhydryl sites as well as at other sites in both cells and purified enzymes.

Anti-Bacterial Agents↗
PubMed1980

Inhibitory studies of DNA, RNA and protein synthesis in Escherichia coli by platinum containing complexes.

Previous studies have shown various platinum containing compounds to be effective anti-tumor agents in man and animals. Many of these compounds have also been shown to be effective inhibitors of bacterial DNA, RNA and protein synthesis. Data is presented here which compares the inhibitory effectiveness of a number of recently synthesized platinum compounds toward the inhibition of the synthesis of DNA, RNA and protein in Escherichia coli. We also compared the effectiveness of these compounds toward the inhibition of bacterial growth. Some of these new derivatives appear to be nearly 3-fold more potent than the more thoroughly studied cis-diamminedichloroplatinum(II) (cis-PDD) and trans-diamminedichloroplatinum(II) (trans-PDD).

Bacterial Proteins↗
PubMed1979

Enhanced inhibition of both cellular protein synthesis and malate dehydrogenase by aged aquoplatinum(II) complexes.

Previous studies have shown cis-diamminedichloroplatinum(II) (Cis) an effective anti-tumour agent in man and animals. Evidence is presented here that formation of aquo complexes of this platinum derivative will significantly enhance its inhibitory properties with respect to two separate biochemical functions, namely inhibition of protein synthesis in hamster medulloblastoma cells and in inhibiting the activity of L-malate dehydrogenase (MDH) in a cell free system. Inhibition of cell protein synthesis rises from 8% using freshly dissolved drug to 30% when aged solutions of drug are employed at an inhibitor concentration of 0.1 mM. The inhibitory enhancement seen using purified malic dehydrogenase increases from 16% (fresh) to 57% (aged) at an inhibitor concentration of 1 mM.

Animals↗
PubMed1978

Effects of ketamine on brain monoamine levels in rats.

The effects of ketamine (50 mg/kg i.p.) on brain monoamines, including epinephrine, norepinephrine, dopamine, serotonin and its metabolite 5-hydroxy indoleacetic acid, were studied in three groups of male Sprague-Dawley rats. A rapid, simple, accurate, and sensitive spectrophotoflurometric method was developed to determine monoamines extracted from rat brain. Ketamine significantly increased brain epinephrine (25%), serotonin (28%) and 5-hydroxy indoleacetic acid (32%) in rats. In contrast, norepinephrine (43%) and dopamine (58%) levels were significantly reduced at 30 minutes. The increase in epinephrine (13%) and decrease in norepinephrine (31%) and dopamine (38%) levels remained significant 12 hours after ketamine injection. Serotonin and 5-hydroxy indoleacetic acid levels returned to almost normal in ketamine pretreated animals after 12 hours. Thus, the ability of ketamine to interfere with monoamine metabolism was revealed.

Animals↗
PubMedDate not supplied

Synthesis of 3 beta-hydroxy-5 alpha-cholest-8-en-7-one and 3 beta-hydroxy-5 alpha-cholest-8-en-11-one: evaluation as potential hypocholesterolemic agents.

An efficient procedure for the chemical synthesis of 3 beta-hydroxy-5 alpha-cholest-8-en-7-one and 3 beta-hydroxy-5 alpha-cholest-8-en-11-one is described. These ketosterols have been shown to have possible significant hypocholesterolemic effects when fed to normal rats at a level of 0.15% in a laboratory chow diet. The diets containing the steroids caused significant decreases in food consumption which were associated with decreases in the rate of gain in body weight.

Animals↗
PubMedDate not supplied

Evaluation of methods for measurement of steroid hormone receptors.

Several factors affecting estrogen receptor assays have been investigated. Pools of rabbit uterus cytosol and human tumor cytosol were utilized to minimize sampling error. Optimum concentration of diethylstilbestrol was found to be 1000 times the highest labeled ligand concentration. Dithiothreitol (DTT) and ionic strength had no effect on receptor value in human tumor cytosols. Optimum pH for estrogen receptor assay is 7.78.

Animals↗