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Biomedical subjects

R Otto

Publications and source records attributed to R Otto.

At least 37 records · Page 2Linked to original sources
PubMed1985

Energy recycling by lactate efflux in growing and nongrowing cells of Streptococcus cremoris.

Streptococcus cremoris was grown in pH-regulated batch and continuous cultures with lactose as the energy source. During growth the magnitude and composition of the electrochemical proton gradient and the lactate concentration gradient were determined. The upper limit of the number of protons translocated with a lactate molecule during lactate excretion (the proton-lactate stoichiometry) was calculated from the magnitudes of the membrane potential, the transmembrane pH difference, and the lactate concentration gradient. In cells growing in continuous culture, a low lactate concentration gradient (an internal lactate concentration of 35 to 45 mM at an external lactate concentration of 25 mM) existed. The cell yield (Ymax lactose) increased with increasing growth pH. In batch culture at pH 6.34, a considerable lactate gradient (more than 60 mV) was present during the early stages of growth. As growth continued, the electrochemical proton gradient did not change significantly (from -100 to -110 mV), but the lactate gradient decreased gradually. The H+-lactate stoichiometry of the excretion process decreased from 1.5 to about 0.9. In nongrowing cells, the magnitude and composition of the electrochemical proton gradient was dependent on the external pH but not on the external lactate concentration (up to 50 mM). The magnitude of the lactate gradient was independent of the external pH but decreased greatly with increasing external lactate concentrations. At very low lactate concentrations, a lactate gradient of 100 mV existed, which decreased to about 40 mV at 50 mM external lactate. As a consequence, the proton-lactate stoichiometry decreased with increasing external concentrations of protons and lactate at pH 7.0 from 1 mM lactate to 1.1 at 50 mM lactate and at pH 5.5 from 1.4 at l mM lactate to 0.7 at 50 mM lactate. The data presented in this paper suggest that a decrease in external pH and an increase in external lactate concentration both result in lower proton-lactate stoichiometry values and therefore in a decrease of the generation of metabolic energy by the end product efflux process.

Energy Metabolism↗
PubMed1985

Control of oxygen uptake, microcirculation and glucose release by circulating noradrenaline in perfused rat liver.

The effect of noradrenaline on oxygen uptake, on periportal and perivenous oxygen tension at surface acini, on microcirculation and on glucose output were studied in isolated rat livers perfused at constant flow with Krebs-Henseleit-hydrogen carbonate buffer containing 5mM glucose and 2mM lactate. Noradrenaline at 1 microM concentration caused a decrease in oxygen uptake, while at 0.1 microM it led to an increase. Both high and low doses of noradrenaline decreased the tissue surface oxygen tension in periportal and - after a transient rise - in perivenous areas. Noradrenaline at an overall constant flow caused an increase of portal pressure and an alteration of the intrahepatic distribution of the perfusate: at the surface of the liver and in cross sections infused trypan blue led to only a slightly heterogeneous staining after a low dose of noradrenaline but to a clearly heterogeneous staining after a high dose. Both high and low doses of noradrenaline stimulated glucose release. All effects could be inhibited by the alpha-blocking agent phentolamine. In conclusion, control of hepatic oxygen consumption by circulating noradrenaline is a complex result of opposing hemodynamic and metabolic components: the microcirculatory changes inhibit oxygen uptake; they dominate after high catecholamine doses. The metabolic effects include a stimulation of oxygen utilization; they prevail at low catecholamine levels. The noradrenergic control of glucose release is also very complex, involving direct, metabolic and indirect, hemodynamic components.

Animals↗
PubMed1985

Surgery and granulocyte transfusions for life-threatening infections in chronic granulomatous disease.

We report two patients with chronic granulomatous disease (CGD) and life-threatening infections: a 10 10/12-year-old boy had Aspergillus fumigatus spondylitis with destruction of the 11th vertebral body and paravertebral abscess formation, and an 8 5/12-year-old boy had multiple Staphylococcus aureus hepatic abscesses with subphrenic abscess formation. Both patients failed to respond to intense antimicrobial therapy but showed a remarkable recovery following surgical drainage combined with granulocyte transfusions. These results suggest that antimicrobial therapy and surgical drainage followed by granulocyte transfusions may be the ideal mode of treatment for severe infections in patients with CGD.

Amphotericin B↗
PubMed1979

[Ultrasonically guided percutaneous fine-needle biopsy (author's transl)].

A new method is described of doing fine-needle biopsies, under continuous visual control with real-time ultrasonic guidance, of the neck, thoracic and abdominal regions. The method decreases the risk of needle puncture and improves the yield of material obtained. It is simple and hardly stresses the patient, pain being only slight and momentary. It can be easily repeated. It is particularly useful for amniocentesis in obstetrics because it employs the shortest possible pathway.

Abdomen↗
PubMed1979

[The problem of the multifocal breast neoplasm].

Nowadays, it is accepted that mammary cancer does not represent a localized tumor only, but a bilateral disease of breast tissues. During a period of 6 years, bilateral manifestations of infiltrating cancer have been observed in 12.7% of all cases. 23.2% of all breast cancer patients had a unilaterial multicentric tumor. The implications of this phenomenon with regard to control and therapy are as follows: As early diagnosis of malignant breast tumors often is possible by means of mammography, this examination should be performed regulary in high-risk patients, especially in cases of known earlier malignancy of one breast. More radical surgery should have priority, in view of the frequently observed multicentricity of breast cancers.

Biopsy↗
PubMed1978

[Erroneous diagnosis in superficial course of the aorta. Demonstration using ultrasound].

In hyperlordosis of the lumbar spine, the abdominal aorta becomes well palpable and behaves like a pulsating tumor in the lower abdomen. This normal finding often cannot be differentiated from pathologic changes by clinical investigation alone. Sonography offers a simple method, without risk, for the definitive diagnosis of the abdominal aorta.

Abdominal Neoplasms↗
PubMed1978

Metabolic responses of females to high intensity interval training of different frequencies.

The purpose of this investigation was to examine the effects of frequency and distance of high intensity, interval training on females. Thirty-two females participated in an eight-week program of interval run training. Subjects were assigned to either a 2 day/week or a 4 day/week group, as well as a high intensity, short distance (50,101,201 meters), or high intensity longer distance (604, 805, 1208 meters) group. Estimates of training intensity were 170% and 130% Vo2max for the short and longer distance groups, respectively. Maximal and submaximal measures of oxygen consumption (Vo2), heart rate (HR), and venous blood lactic acid were determined prior to and following the training program. After training, there was a significant increase (P less than 0.01) in Vo2max (13%) (deltax = 0.32 1/min or 5.2 ml/kg.min). Maximal VE increased approximately 12% after training (P less than 0.01). Max HR, max lactic acid, and submax Vo2 were not altered by the training. However, HR submax decreased significantly (P less than .05) after training by approximately 6%. Analysis of coveriance indicated that these changes were independent of training frequency, distance, and intensity. It was concluded that the changes in aerobic power and submaximal HR of females are independent of frequency, distance, and intensity of high-intensity interval training programs.

Adult↗