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Biomedical subjects

M T Kopetzky

Publications and source records attributed to M T Kopetzky.

15 recordsLinked to original sources
PubMed1989

Chronic exposure to carbon monoxide at high altitude: effects on mean electrical axis.

The effects of breathing CO continuously at high altitude on the mean electrical axis of the heart, hematocrit ratio and body weight were studied in laboratory rats. Laboratory rats were exposed for 6 weeks to: 100 or 500 ppm CO; 15,000 feet stimulated high altitude (SHA); or 100 or 500 ppm CO at SHA. SHA decreased body weight significantly; CO and CO-SHA interaction had no significant effect on body weight. CO and SHA increased hematocrit ratio significantly; five hundred ppm CO increased hematocrit ratio to a greater extent than 100 ppm CO. There was a significant interaction between 500 ppm CO and SHA on hematocrit ratio. The mean electrical axis (MEA) was shifted to the right by SHA, and shifted to the left by CO. The effect was dose dependent, with the greater left shift occurring with 500 ppm CO. There was a significant interaction between 500 ppm CO and SHA on the MEA. These results indicate that, in general, the effects produced by 15,000 feet SHA are not intensified by 100 ppm CO, but are intensified by 500 ppm CO.

Altitude Sickness↗
PubMed1988

Prolonged serum levodopa levels with controlled-release carbidopa-levodopa in the treatment of Parkinson's disease.

Twenty parkinsonian patients (Hoehn and Yahr scale, I through III) were treated with controlled-release carbidopa-levodopa (CR-2 or CR-3) and standard carbidopa-levodopa (Sinemet, 25 mg/100 mg) in a double-blind, crossover pharmacokinetic and clinical efficacy study. The controlled-release agents had a slower rise to peak plasma values and flatter pharmacokinetic curves than did the standard. The area under the curve for CR-3 was significantly increased by 55.5% as compared with standard agent and by 84.2% as compared with CR-2. No differences in clinical efficacy were found between controlled-release agents and the standard agent for this group of parkinsonian patients with mild to moderate severity. The dissociation between the prolonged serum levodopa levels and unimproved clinical efficacy may have resulted from the absence of patients with prominent motor fluctuations and/or substantial serum levodopa variability that was especially prominent with CR-3.

Adult↗
PubMed1982

Statistical analysis of effect of anoxia on rate of change of ventricular pressure.

Hearts from 32 male Sprague-Dawley rats were studied to determine effects of anoxia on ventricular contractility. Maximum rate of ventricular pressure changes with time (Pmax) were obtained from simultaneous recordings of right and left ventricular pressure curves. Peak aortic flow and heart rate were measured. Anoxia was produced by 100% N2 respiration. Statistical models were repeated-measures analysis of variance and randomized block factorial analysis of variance. Alpha was 0.05. Heart rate during anoxia was significantly lower than during the 1st min of recovery. Heart rate during both these periods was significantly lower than in preanoxia or the remainder of recovery. Peak aortic flow was not significantly altered. In left ventricles positive Pmax was significantly higher than negative Pmax. In right ventricles positive and negative Pmax were not significantly different. Left ventricular Pmax was significantly depressed during anoxia, whereas right ventricular Pmax was not. Significant differences in pressure developed per mass of tissue was a possible source of variation in right (0.12 +/- 0.002 mmHg/mg) and left (0.16 +/- 0.009 mmHg/mg) ventricular contractile maintenance.

Analysis of Variance↗
PubMed1981

Alterations in responses to drugs of atria from white rats acclimated to hypobaric hypoxia.

To test the hypothesis that acclimation to simulated high altitude (SHA) may occur in the tissues as well as in the systemic regulatory apparatus of an organism, atria isolated from young rats acclimated to SHA of 6,000 m and from control rats were observed under normoxic conditions. SHA atria have slower spontaneous heart rates than atria isolated from controls (209 +/- 4 vs. 228 +/- 3, P less than 0.001). SHA atria are more sensitive to pentobarbital sodium (P less than 0.001) and ethanol (P less than 0.06): spontaneous mechanical activity stops at a lower drug concentration in SHA than in control atria. SHA atria are less sensitive to norepinephrine in the concentration range of 7.9 X 10(-9) to 3.1 X 10(-6) M and respond to increased bath concentrations (3.8, 5.8 and 7.8 mM) of calcium with a significantly (P less than 0.04) smaller chronotropic response and a greater inotropic response than atria from control animals. These data support the above-mentioned hypothesis.

Acclimatization↗
PubMed1976

Botanical trash present in cotton before and after saw-type lint cleaning.

The % by weight content of leaf-like, stem, boll, seed, and weed materials sifted (3360 mum greater than particle size greater than or equal to 595 mum) from visible wastes of the Shirley Analyzer was determined for a lint sample taken after ginning but before cleaning and for a second lint sample taken after one stage of saw-type cleaning. The % by weight content for bract and leaf increased with decreasing trash particle size. The content of cotton seed coat fragments decreased with reduction in trash particle size. Approximately 1/4 of the botanical wastes consisted of weed materials, including grass particles. Lint cleaning was ineffective in reducing the % by weight content of leaf-like trash. Some selective removal of stem trash occurred as a function of lint cleaning.

Byssinosis↗
PubMed1976

Variation in trash composition in raw cottons.

Raw cotton from 4 machine picked varieties and 2 machine stripped varieties is examined by stereomicroscope and bright-field microscopy for presence of plant trash(bract, leaf, stem, seed, boll, and weed fragments-size range 841-2000mum) that gives rise to cotton dust during yarn manufacturing operations. Bract was found to be the major trash component in all raw cottons examined. Cotton leaf and non-cotton weed materials were also major trash components in most raw cottons.

Byssinosis↗
PubMed1976

Response of asthmatics to methacholine and suggestion.

Effects of diluent, methacholine, and suggestion on pulmonary function were studied in 9 asthmatic subjects. On day 1, flavored diluent was given as a control preparation. On day 2, increasing concentrations of similarly flavored methacholine were administered. On day 3, the effect of flavored diluent plus suggestion was studied. Although all variables were affected, the dose-response relationships for methacholine were most pronounced for specific airway conductance and airway resistance, in contrast to maximal mid-expiratory flow, forced expiratory volume in 1 sec, and forced vital capacity. Suggestion toward bronchoconstriction significantly affected only the plethysmographic parameters, specific airway conductance, and airway resistance, and not the spirometric variables. Both airway resistance and 1-sec forced expiratory volume showed slight, but significant, changes as a result of bronchodilator suggestion, which was used to overcome the suggestion toward bronchoconstriction. Because suggestion had a greater effect on large airways than peripheral airways, a role for the vagus is implied. Thus, any protocol using body plethysmography must consider a possible effect of suggestion on results.

Adolescent↗