Biomedical subjects

L Johansen

Publications and source records attributed to L Johansen.

6 recordsLinked to original sources

PubMed1992

Elevated muscle acidity and energy production during exhaustive exercise in humans.

This study examined the effect of previous intense exercise on energy production during exhaustive exercise. Subjects (n = 6) performed dynamic knee extensor exercise to exhaustion twice (Ex1 and Ex2) separated by 16 min of recovery consisting of 10 min of rest, 3.5 min of very high-intensity intermittent exercise, and a further 2.5 min of rest. This resulted in an elevated muscle lactate concentration of 13.1 mmol/kg wet wt before Ex2. Muscle lactate concentration was the same at end of Ex1 and Ex2, but the accumulation of lactate and net lactate release during Ex2 was reduced (P < 0.05) by 67 and 38%, respectively. The time to exhaustion was 3.73 and 2.98 min, respectively, and the mean rate of net lactate production for Ex2 was lower (P < 0.05) than for Ex1 (4.6 +/- 1.2 and 9.6 +/- 1.7 mmol.min-1.kg wet wt-1, respectively). Leg O2 uptake was the same for Ex1 and Ex2. Muscle pH (6.85) was lowered (P < 0.05) before Ex2, but at the end of Ex2 (6.77) it tended (P < 0.1) to be higher compared with that at the end of Ex1 (6.73). In summary, the net lactate production rate is reduced but the aerobic energy production is not significantly altered when intense exercise is repeated. Fatigue and the lowered glycolysis do not appear to be caused by the elevated acidity per se before exercise.

Acid-Base Equilibrium↗

PubMed1990

The presence of human papillomavirus (HPV) in solitary adult laryngeal papillomas demonstrated by in-situ DNA hybridization with sulphonated probes.

Human papilloma virus (HPV) types 6 and 11 have been repeatedly demonstrated in multiple laryngeal papillomas, and there is little doubt that these lesions are caused by HPV. It has been clearly demonstrated in recent reports that the clinical course of solitary adult onset laryngeal papillomas is entirely different from that of multiple papillomas of juvenile as well as of adult onset. We here report the presence of HPV types 6 and 11 in 19 out of 20 solitary papillomas from 16 patients, while HPV types 16 and 18 were totally absent. We conclude that the milder clinical course in such patients is most likely to be due to host factors, rather than to viral factors.

DNA Probes, HPV↗

PubMed1990

Adjuvant bestatin (Ubenimex) treatment following full-dose local irradiation for bladder carcinoma.

The clinical value of adjuvant bestatin (Ubenimex) immunotherapy has been examined in a group of patients with urinary bladder cancer. Patients with non-metastatic transitional cell carcinoma of the bladder, scheduled for full-dose local irradiation therapy (64 Gy), were randomly allocated to adjuvant oral bestatin treatment (30 mg daily for at least 1 year), starting at completion of irradiation, or no bestatin. The trial included 194 evaluable patients with a follow-up period of 1.5-9.5 years. The overall survival of the two groups of patients did not differ statistically significantly (97 patients in each). Subgrouping of the patient material gave no evidence that the clinical efficacy of bestatin is related to sex, tumor category or malignancy grade.

Adjuvants, Immunologic↗

PubMed1979

Uptake of 3H-L-carnitine by isolated rat epididymal tubules.

The uptake of radiolabeled L-carnitine has been studied in isolated epididymal tubules from the rat. The uptake of 3H-L-carnitine increases with a temperature coefficient KT of 0.22 nmol carnitine.mg protein-1 in the intermal 22--31 degrees and with a low uptake at 4 degrees C. The uptake of radiolabeled carnitine (as percent) is reduced at high concentrations of L-carnitine, by deoxycarnitine but not by D-carnitine. This uptake mechanism is especially active in the distal caput and corpus segments of the epididymis. Thus, an uptake mechanism for carnitine is present in the epididymal cells which besides the carnitine uptake in spermatozoa is responsible for the dramatic increase in carnitine concentration in cauda epididymis.

Animals↗

PubMed1978

Carnitine-binding related supressed oxygen uptake by spermatozoa.

L-carnitine (25 mM) reduced oxygen uptake immediately by 40% in ejaculated bovine spermatozoa, but not in ejaculated human spermatozoa or in spermatozoa from bovine and rat epididymis. [3H]-L-carnitine was bound five times as much to ejaculated bovine spermatozoa as to bovine spermatozoa from the cauda epididymis and to human ejaculated spermatozoa. This indicates the presence of a factor in the accessory male sex organs which, through changes in the membrane and/or intracellulary, increases the [3H]-L-carnitine binding sites and makes the spermatozoa susceptible to carnitine inhibition.

Animals↗

PubMed1975

Physiological and biochemical role of the butanediol pathway in Aerobacter (Enterobacter) aerogenes.

Aerobacter (Enterobacter) aerogenes wild type and three mutants deficient in the formation of acetoin and 2,3-butanediol were grown in a glucose minimal medium. Culture densities, pH, and diacetyl, acetoin, and 2,3-butanediol levels were recorded. The pH in wild-type cultures dropped from 7.0 to 5.8, remained constant while acetoin and 2,3-butanediol were formed, and increased to pH 6.5 after exhaustion of the carbon source. More 2,3-butanediol than acetoin was formed initially, but after glucose exhaustion reoxidation to acetoin occurred. The three mutants differed from the wild type in yielding acid cultures (pH below 4.5). The wild type and one of the mutants were grown exponentially under aerobic and anaerobic conditions with the pH fixed at 7.0, 5.8, and 5.0, respectively. Growth rates decreased with decreasing pH values. Aerobically, this effect was weak, and the two strains were affected to the same degree. Under anaerobic conditions, the growth rates were markedly inhibited at a low pH, and the mutant was slightly more affected than the wild type. Levels of alcohol dehydrogenase were low under all conditions, indicating that the enzyme plays no role during exponential growth. The levels of diacetyl (acetoin) reductase, lactate dehydrogenase, and phosphotransacetylase were independent of the pH during aerobic growth of the two strains. Under anaerobic conditions, the formation of diacetyl (acetoin) reductase was pH dependent, with much higher levels of the enzyme at pH 5.0 than at pH 7.0. Lactate dehydrogenase and phosphotransacetylase revealed the same pattern of pH-dependent formation in the mutant, but not in the wild type.

Acetates↗