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Biomedical subjects

G Urban

Publications and source records attributed to G Urban.

At least 55 records · Page 3Linked to original sources
PubMed1991

Effect of acute ethanol on esophageal motility in cat.

In man, acute ethanol administration decreases lower esophageal sphincter pressure (LESP), prolongs the duration, and lowers the amplitude of esophageal contractions. These changes may contribute to gastroesophageal reflux and esophagitis. To evaluate the underlying mechanisms of these changes an animal model is needed. Hence, we studied the effect of various doses of ethanol on esophageal motility in cats, an animal with an esophagus similar to man's. Similar to man, intravenous administration of ethanol significantly decreased LESP and amplitude of lower (smooth muscle portion) esophageal contractions. It also prolonged the duration of lower esophageal contractions, even through it had no effect on contraction velocity. The effect of ethanol on upper (striated muscle portion) esophagus was different. Ethanol had no effect on the amplitude of contractions, whereas it prolonged their duration and decreased their velocity. The effect of acute ethanol on LESP in four withdrawing alcoholic cats was similar to controls. However, the acute effect of ethanol on the esophageal contractions was less marked in alcoholics. Bilateral cervical vagotomy and intravenous injection of the neurotoxin tetrodotoxin before the administration of ethanol did not prevent the effect of ethanol on LESP. This data suggests that cat esophagus is a good model for studying the underlying mechanisms of the effects of acute ethanol because its response is similar to the esophagus of man, and the acute effect of ethanol on LESP is not neurally mediated but is the result of its direct effect on muscle.

Alcohol Drinking↗
PubMed1990

Palliative chemo-radiotherapy with ifosfamide and epirubicin as first-line treatment for high-risk metastatic breast cancer. Results of a prospective multicenter trial.

From June 1986 to December 1988, 107 patients (median age, 49 years; median performance score, 1) with haematogeneous metastases from breast carcinoma were treated with concomitant radiation and chemotherapy. Overall, 97% of the patients had been pretreated with surgery; 65%, with radiation; and 56%, with hormones. In all, 38% had received adjuvant chemotherapy. Patients with prior palliative chemotherapy were excluded from the study. All patients fulfilled at least two high-risk criteria. Chemotherapy was given according to the EI protocol (4-epirubicin and ifosfamide), and all patients simultaneously received radiation to the main tumour sites. Gastro-intestinal toxicity was moderate (11.1%, WHO grade 4), and bone marrow depression was marked in all cases. After three treatment courses, the overall response rate was 67% [21% complete response (CR), 46% partial response (PR)]. In all, 28% had stable disease (NC) and the rate of progressive disease (PD) was 5%. The median duration of tumour response was 8 months, with 12 months for CRs, 9 months for PRs and 6 months for NCs. The median survival was 13.5 months.

Adult↗
PubMed1990

Ethanol-induced esophageal motor disorder: development of an animal model.

Abnormal esophageal motility has been reported in alcoholics. This includes abnormally high esophageal contraction amplitudes (ECA) and elevated lower esophageal sphincter pressures (LESP). However, an animal model is lacking for evaluating the underlying mechanisms. To develop such a model of ethanol-induced esophageal motor dysfunction, esophageal manometry was done in control, chronically intoxicated, and withdrawing cats. Ethanol was administered for at least 30 days via gastrostomy tube and blood alcohol levels, typically 300 mg/dl, were adjusted to maintain inebriation. LESP and upper (striated muscle) and lower (smooth muscle) ECA were elevated in male withdrawing cats. In intoxicated cats only upper ECA was elevated. Surprisingly, LESP and ECA were not significantly affected in females. Duration of ECA was prolonged in both male and female intoxicated cats. These findings indicate that: (1) similar to withdrawing men, ECA and LESP are elevated in withdrawing male cats; (2) ethanol-treated cats are an appropriate model for studying the mechanism of ethanol effects on esophageal motor function; (3) gender has a significant role in influencing the effects of alcohol.

Animals↗
PubMed1990

High resolution multi-temperature sensors for biomedical application.

A temperature sensor array was designed in order to study local temperature variations and temperature gradients in biological samples. The sensor probe was inserted in the optical cortex of rabbits in order to study temperature changes during normal brain activity as well as under artificial ventilation conditions. Temperature sensitive areas of 0.14 mm x 0.1 mm are arranged in a row with interdistances of 0.4 mm yielding high spatial resolution. A temperature resolution of 0.1 mK and a 90% response time of maximum 3 milliseconds was obtained utilizing the high temperature dependence of 2%/K of the conductivity of vacuum evaporated germanium films. The sensor is passivated by a 1 micron thick PECVD-silicon nitride layer and can be placed on glass-, alumina- and polymer substrates. For brain tissue studies, in order to minimize tissue damage the temperature sensors were placed on a 0.1 mm thick needle-shaped glass substrate. A sensor element mounted on a glass substrate and immersed in water showed a self heating of less than 5 mK due to the applied measurement current of 2.1 microA.

Animals↗
PubMed1984

Effects of aerobic exercise and weight loss on riboflavin requirements of moderately obese, marginally deficient young women.

In a previous study, exercise was shown to increase riboflavin requirements of active, normal weight young women. The present study examined the effect of exercise and weight loss on riboflavin status of moderately overweight women. The experiment was designed as a two-period cross-over with an initial base-line period and two 5-wk metabolic periods. The basic diet contained 1200 kcal with a riboflavin concentration of 0.8 mg/1000 kcal. Exercise consisted of a program of dance exercise. Riboflavin depletion, as measured by increased erythrocyte glutathione reductase activity coefficients and decreased urinary excretion of riboflavin, occurred during both nonexercise and exercise periods. Erythrocyte glutathione reductase activity coefficients increased from a base-line mean of 1.28 +/- 0.11 to 1.40 +/- 0.12 during nonexercise and to 1.49 +/- 0.16 during exercise. Urinary excretion of riboflavin fell from 48 +/- 12% of intake during base-line to 30 +/- 13% during nonexercise and to 19 +/- 6% during exercise. Riboflavin depletion was not related to the rate or composition of weight loss or to change in aerobic capacity.

Adult↗
PubMed1981

[Radiological investigations of cobalamin supply with regard to folate status (author's transl)].

In a study with 307 volunteers we estimated the cobalamin status by radiochemical (plasma cobalamin) and haematological (lobe average of granulocytes) methods. As there is a close biochemical connection between the folate and cobalamin metabolism (methyl-tetrahydrofolate-trap hypothesis) we additionally determined the plasma- and erythrocyte folate levels in 307 volunteers by radioimmunoassay. Further metabolic studies in humans showed that a cobalamin concentration of less than 160 pg/ml indicates a deficient supply. In the present study 6% of the men and 8% of the women showed an inadequate alimentary supply.

Erythrocytes↗
PubMed1980

[Biochemical and hematological parameters for the estimation of folate status in man. 3. Importance of formiminoglutamic acid excretion in the urine in comparison to other measurements].

In a study on 250 industrial workers the amount of the formiminoglutamic acid excretion in urine was measured by an enzymatic spectrophotometric method. For the estimation of the folacine status the vitamine concentration in serum and erythrozytes was determined as well as the segmentation of the neutrophilic granulocytes. As shown in previous studies these parameters indicate the degree of folate supply. A correlation between the FIGLU excretion in urine and other folate dependent parameters could not be demonstrated. Criterial to judge the folate supply are the radioimmunological determination of folacine concentration in serum and erythrocytes as well as the estimation of the segmentation of the neutrophilic granulocytes.

Female↗
PubMed1978

[Biochemical and hematological measures for determination of folate status in humans. 1. Relation between serum folate and segmentation of neutrophil granulocytes].

In a study on 130 student volunteers the segmentation of neutrophil granulocytes was measured. The serum folate concentration was used as biochemical reference. Both parameters indicate the state of folate supply or the degree of folate deficiency, respectively. Considering the haematologic response as an objective criterion only 71% of the examines showed an adequate folate status. 11% were found "deficient" and 18% were in a marginal state of folate supply. This result was confirmed by repeating the experiment. Further studies are to include folate concentration of erythrocytes and urine concentration of formiminoglutamic acid.

Adult↗