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C Ott

Publications and source records attributed to C Ott.

At least 55 records · Page 3Linked to original sources
PubMed1989

[The behavior of leukocyte rheology in induced ischemia in peripheral arterial occlusive disease].

We studied the quantitative and qualitative behaviour of white blood cells (WBCs) at rest and after standard treadmill exercise in 20 male stage II peripheral vascular disease (PVD) patients, compared to 20 healthy matched controls. The aim of this study was to define the role of WBCs in PVD. The results confirm the WBC count was significantly increased in PVD patients. Surprisingly, however, the only rheological WBC variable which showed a significant variation during the ischaemic pain caused by treadmill exercise was the filterability of mononuclear leukocytes. This would seem to identify disturbances in mononuclear filter-ability, associated with ischaemic pain resulting from claudication, as a functional sign of PVD.

Aged↗
PubMed1989

[Infection and tissue ischemia: what role does the rheologic behavior of blood cells play?].

It is not clear how acute infection is associated with a subsequent ischaemic brain infarction. Infection may, in fact, cause changes in blood fluidity. Abnormalities in blood flow, particularly in white blood cell rheology, are known to be precipitating factors for ischaemic events. Therefore the rheological behaviour of the erythrocytes and the leukocytes were studied 30 days after the onset of acute bacterial infections in 30 patients and in a group of 50 controls (matched for sex, body mass index and cardiovascular risk factors). Our results show a significant impairment in the flow properties of the leukocytes in the patients compared to the controls, and indicate disturbances in leukocyte rheology might be considered an additional risk factor for ischaemic brain infarction when it occurs shortly after febrile infection.

Aged↗
PubMed1989

Effect of exercise duration on lactate kinetics after short muscular exercise.

Arterial blood lactate concentrations were measured in six normal males before, during and after 3- and 6-min bicycle exercises performed at three different work rates. The lactate recovery curves were fitted to a bi-exponential time function consisting of a rapidly increasing and a slowly decreasing component, which supplied an accurate representation of the changes in lactate concentration. Variations in the parameters of this mathematical model have been studied as a function of the duration of exercise and of the work rate, showing a clear dependence on exercise duration such that increasing exercise length decreases the velocity constants of the fitted curves. In terms of the functional meaning which can be given to these constants, this result indicates that extending exercise duration from 3 to 6 min reduces the ability of the whole body to exchange and remove lactate. This effect did not qualitatively modify the one already described, which is due to increased work rates, but it shifted the ability to exchange and remove lactate towards lower values. The main conclusion of the study is that lactate kinetic data vary as a function of time during exercise. This inference must be accounted for in the interpretation of lactate data obtained during muscular exercise.

Adult↗
PubMed1989

Comparison of arterial and venous blood lactate kinetics after short exercise.

Seventeen healthy male volunteers participated in this study designed to compare arterial with both arterialized venous and venous lactate kinetics after short exercise. Blood samples drawn before, during, and after bicycle exercise were analyzed continuously for lactate. A mathematical function incorporating two exponential terms was fitted to the arterial, arterialized venous, and venous lactate recovery curves, and the parameters of the mathematical function were compared using a linear regression. All parameters measured on or fitted to the arterialized venous curves correlated well with the respective arterial data (correlation coefficient R = 0.82 to 0.99, P less than 0.001). Among the parameters obtained from the fit to the venous curves, only those describing lactate removal correlated closely with the arterial results. It is concluded that for lactate kinetic studies during recovery following short-term muscular exercise, the information obtained from arterialized venous blood is comparable to arterial blood, whereas the use of venous blood, from the sampling site in this study, appears suitable for determining only the parameters for lactate disappearance. These conclusions are illustrated by the comparison between arterial, arterialized venous, and venous parameters as a function of the work rate of the previously performed exercise.

Adult↗
PubMed1988

[Salmonella enteritis with a serious course in patients without a suppressed immune system].

Infections with salmonellae causing gastroenteritis rarely lead to bacteremia (1-4%), and serious courses are almost exclusively observed in patients with a compromised immune system. In 1986-1987 we observed 4 patients with no evidence of disturbed cell-mediated immunity, who presented with severe bacteremic salmonellosis (1 patient with S. Heidelberg and 3 with S. enteritidis). 1 patient had septic shock with rhabdomyolysis, 1 patient acute renal failure and 1 patient acute endocarditis.

Acute Kidney Injury↗
PubMed1988

Prolonged submaximal exercise and L-carnitine in humans.

Changes in the main physiological parameters and circulating indicators of carbohydrate, protein, lipid (and ketone body) metabolism were measured in ten exercising subjects before L-carnitine (L-carn) loading, after 4 weeks of daily loading with 2 g L-carn, and 6-8 weeks after terminating L-carn administration. Measurements were made on venous blood samples collected during each experiment at fixed time intervals over an initial rest of 45 min, 60 min bicycle exercise performed near 50% VO2max and 120 min recovery. Free and total plasma carnitine levels reached a plateau corresponding to an average rise of 25% for both fractions, 9-10 days after the beginning of the L-carn diet. These levels returned to their initial values 6-8 weeks after cessation of the supply. Generally L-carn supplementation did not significantly modify the physiological parameters and circulating metabolites. No distinct increase of the relative participation of endogenous lipids in the fuel supply of prolonged submaximal exercise was observed. In normal human subjects the increased demand for fatty acid oxidation resulting from exercise seems to be adequately supported by endogenous levels of carnitine.

Adult↗
PubMed1986

Work rate-dependent lactate kinetics after exercise in humans.

Arterial blood lactate concentrations were measured on 19 subjects before, during, and after a 3-min bicycle exercise at several work rates, and the concentrations during the recovery phases were fitted to a biexponential time function consisting of a rapidly increasing and a slowly decreasing component. Highly significant correlations with the work rate of the exercise preceding the recovery were found for all the parameters of the fitted equation. The two velocity constants show inverse linear relationships, whereas the other parameters vary according to a definite power function. A functional meaning has been given to the two velocity constants, namely the ability of the tissues to exchange and to remove lactate. For the group of subjects studied, after exercises at work rates below about 3.5 W/kg, the tissue's ability to utilize, and possibly to exchange lactate, increases over values generally reported for resting conditions, whereas after exercises at higher work rates the inverse occurs. Lactate kinetics during recovery appear to be the result of two underlying processes, one enhancing the ability of the tissues to exchange and remove lactate and the other restraining it.

Adult↗
PubMed1985

Plasticity in the 904-day-old male rat cerebral cortex.

Ten pairs of male Long-Evans rats living in nonenriched environments (3 rats per small cage) were transferred to either enriched environments (10 rats per large cage plus "toys") or nonenriched environments (2 rats per small cage) at 766 days of age. One hundred and thirty-eight days later, at 904 days of age, the cerebral cortical thickness from these animals was measured on projected, 10-micron, thionine-stained, transverse sections. Although the thickness in the enriched rats was greater than in the nonenriched rats in all sections through the frontal, parietal, and occipital cortices, the 4 to 10% differences were statistically significantly different in only the frontal and occipital cortices. Right greater than left cortical thickness differences were not statistically significant in either the enriched or the nonenriched animals by 904 days of age. Neuron and glial counts were made on enlarged photographs of area 18 in the occipital cortex on 6-micron-thick, luxol fast blue-stained sections. No significant differences in cell counts were noted between the enriched and nonenriched animals. No significant differences in neuronal counts were found among 108-, 650- (from previous experiments), and the 904-day-old nonenriched rats. The notable findings were the plasticity of the extremely old, enriched rats' occipital cortex and the lack of the loss of neurons in cerebral cortical area 18, whether or not the environments were enriched. These results showed that the cerebral cortex remained structurally plastic throughout the lifetime of the organism.

Age Factors↗
PubMed1985

Hemodynamic effects of neurohypophyseal peptides with antidiuretic activity in dogs.

Arginine vasopressin (AVP) is known to produce increases in total peripheral resistance (TPR) and mean arterial pressure (MAP) and decreases in heart rate (HR), cardiac output (CO), and plasma renin activity (PRA). Some recent observations with AVP and synthetic analogues have suggested that under certain conditions, AVP can induce cardiovascular and reninsecretory responses in the opposite directions. To characterize the receptors mediating these responses, the effects of AVP, oxytocin, and synthetic neurohypophyseal analogues with specific antidiuretic, vasoconstrictor, or oxytocic activities were studied in conscious dogs. AVP and 2-phenylalanine-8-ornithine-oxytocin (Phe2Orn8OT, a selective vasoconstrictor agonist) produced similar responses when infused at 10 ng X kg-1 X min-1. That is, TPR and MAP increased, and CO, HR, and PRA decreased. Pretreatment with a selective vasoconstrictor antagonist, [1-(beta-mercapto-beta,beta-cyclopentamethylenepropionic acid) 2-(O-methyl)tyrosine]AVP, abbreviated d(CH2)5Tyr(Me)-AVP (10 micrograms/kg), blocked the actions of Phe2Orn8OT. However, in the presence of d(CH2)5Tyr(Me)AVP, AVP actually decreased TPR and increased CO, HR, and PRA. An analogue with selective antidiuretic activity, 4-valine-8-D-AVP (VDAVP, 10 ng X kg-1 X min-1), produced the same effects as the combination of vasopressin plus d(CH2)5Tyr(Me)AVP. Neither the effects of VDAVP nor of AVP plus antagonist were blocked by propranolol (1 mg/kg). These data indicate that vasopressin, by its antidiuretic activity, produces cardiovascular effects that are opposite to many of those produced by its vasoconstrictor action and that these effects are not dependent on mediation by beta-adrenoceptors.

Animals↗
PubMed1980

Blood pyruvate recovery curves after short heavy submaximal exercise in man.

Arterial pyruvate and lactate concentrations were measured after short heavy submaximal exercise on a bicycle ergometer, at 10 or 30 s time intervals, on six male subjects. During most of the first 2 min of recovery pyruvate concentration decreased. Thereafter, it increased and reached its maximum within the 5th to 9th min of recovery. Finally, it decreased gradually as a function of time. Recovery curves could be accurately described after a short delay time following the end of the exercise, by a sum of three exponential terms according to the equation: (Formula: see text), where the time origin (to) is fixed at about 1-1.5 min(delay time) after the end of exercise, t is the time after to, Y(O) and Y(t) are the concentrations of pyruvate respectively at times zero and T, and Ai and zi are constants. The velocity constant of the final arterial blood pyruvate decrease was similar to that of the simultaneously measured lactate, indicating that the rate of lactate removal is closely related to that of pyruvate. This is consistent with the fact that pyruvate is a necessary intermediate in the lactate metabolism.

Adult↗
PubMed1977

[A year's practice of surgery for arteritis after the age of 70 years (author's transl)].

Surgery of the elderly arteritic raises the problem of operative risk due to pre-existing defects at an advanced stage of the arterial disease and the danger of tiring investigations, anesthetics and repeated operations. Out of 271 arteritics operated on during 1975, half (135) were aged over 70 years. 92, i.e. two thirds were operated on at the terminal stage of their arteritis. The operative indications depended on the clinical, arteriographic, psychological and sociological data. The past history in many cases of heart attacks and cerebro-vascular accidents made the utility and necessity of the operation debatable. The technical choice, sympathectomy or plastic operation, depended on which presented the less risk. Although amputation is still necessary for massive gangrene (50 p. cent survival) one should always attempt to save the leg. Lumbar sympathectomy seems less aggressive; reconstructive surgery is, with greater risk, more effective at stage IV. The final result of the year showed 72.6 p. cent survivors including 56.3 p. cent successes and 16.3 p. cent amputations and a mortality of 27.4 p. cent. But all the failures were situated at stage IV of the arteritis, and the disturbances are increased by the patients' age. We can thus say that it is possible to render survival comfortable for three quarters of our operated patients.

Age Factors↗
PubMed1974

[Safety in skiing].

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Accident Prevention↗