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Biomedical subjects

R Jacob

Publications and source records attributed to R Jacob.

At least 199 records · Page 11Linked to original sources
PubMed1982

Response of blood pressure and cardiac myosin polymorphism to swimming training in the spontaneously hypertensive rat.

Cardiac muscle can adapt to different functional demands, as evidenced by polymorphism of myosin. Pressure load in spontaneously hypertensive rats induced a shift of the myosin isoenzymes towards myosin V3 (18% V1, 27% V2, 55% V3) relative to normotensive Wistar rats (49% V1, 29% V2, 22% V3). A swimming routine with Wistar rats resulted in a shift towards myosin V1 (72% V1, 18% V2, 10% V3). The training effect is not restricted to normotensive rats, since spontaneously hypertensive rats subjected to the same swimming routine exhibited a myosin isoenzyme pattern (38% V1, 31% V2, 31% V3) approaching that of the sedentary Wistar rats. Swimming training can, therefore, prevent the myosin isoenzyme redistribution towards myosin V3 found in sedentary spontaneously hypertensive rats. Furthermore, systolic blood pressure was significantly reduced (130 +/- 8 mmHg (1 mmHg = 133.322 Pa) ) in the swim-trained compared with the sedentary spontaneously hypertensive rats (157 +/- 12 mmHg). The training-induced changes in myosin polymorphism and systolic blood pressure are, at least partially, attributed to substantially normalized sympathetic activity. The functional relevance of swimming training in the spontaneously hypertensive rat is seen in the increased potential of coping with situations requiring fast contraction which may occur during sudden physical exertion or emotional stress.

Animals↗
PubMed1981

One-hour serum xylose as an absorption test in the tropics.

The 1-hour serum xylose (surface area corrected) as an indication of xylose absorption after 5 g oral D-xylose has been compared with the 5-hour urine excretion test in a tropical population. The study confirmed that the peak serum xylose concentration occurs at 1 hour and that correction to a constant body surface are improves the discrimination between subjects with normal and impaired xylose absorption. The significantly lower reference range for the 1-hour surface area corrected serum xylose (0.55-1.11 mmol/l) compared to the UK figure reflects the reduced absorptive capacity of the jejunum, a result of tropical enteropathy. In view of the difficulties in obtaining accurate urine collections in tropical countries, especially in field studies, it is recommended that the 1-hour serum xylose (surface area corrected) should be adopted as the standard test of xylose absorption.

Body Surface Area↗
PubMed1980

Epinephrine-induced hypoaminoacidemia in normal and diabetic human subjects: effect of beta blockade.

To evaluate the effect of epinephrine on the circulating amino acids, we infused epinephrine into normal human subjects and juvenile-onset diabetic patients given a constant basal infusion of insulin. Epinephrine infusion produced an identical 350--400 pg/ml rise in plasma epinephrine in both groups. In normal subjects, epinephrine caused a progressive 26% reduction in total circulating amino acids, despite unchanged levels of plasma insulin. This effect was most pronounced for the branched amino acids, which fell by 40% (P < 0.001). Plasma alanine was the only amino acid which failed to decline. Similarly, infusion of epinephrine in the insulin-infused diabetics produced a 23% fall in total amino acids, a 37% decline in branched chain amino acids, but no change in plasma alanine. Saline infusion in the insulin-infused diabetics had no effect on plasma amino acid concentrations. In addition, when epinephrine was infused into two insulin-withdrawn diabetics, a comparable hypoaminoacidemic response was observed. The infusion of propranolol in both normal and diabetic subjects totally prevented the epinephrine-induced fall in plasma amino acids. It is concluded that (1) increments in epinephrine similar to those observed in stress cause a decline in circulating amino acids (except alanine) which is greatest for the branched chain amino acids; (2) this hypoaminoacidemic effect occurs in the absence of a rise in plasma insulin and diabetic subjects, as well; and (3) epinephrine-induced changes in amino acid regulation are prevented by beta-adrenergic blockade. Our findings suggest that, in contrast with glucose and fat metabolism, epinephrine and insulin may have similar, rather than antagonistic, effects on plasma amino acid metabolism.

Adult↗
PubMed1978

[Psychologic guidance of the cancer patient].

Cancer belongs to these diseases threatening severely the lives of patients affected by cancer. Therefore, cancer is connected with psychic responses on the part of the patient. The response as a result of the disease is intensified by negative environmental experiences. The physician has to make due allowance for this fact in the patient's guidance. At the beginning the pros and cons of a truthful information of the patient are discussed. In the following an inhouse model of the care of patients is presented according to which the patient is faced with his diagnosis and prognosis. An attempt is made of helping the patient "to integrate" his disease and to cope with "his" cancer problem. This also includes the guidance of the relations.

Family↗
PubMed1978

[Unloaded shortening velocity of the myocardium as an index of contractility (author's transl)].

An experimental study attempts to clarify the reasons for a fashionable over- or underestimation of the unloaded shortening velocity of the myocardium (Vmax) as an index of "contractility" in international cardiological literature. Long-term investigations on the isolated myocardial preparation as well as on the heart in situ support our own position: 1. Vmax of the myocardium is, without doubt, a value of greater relevance in muscle physiology independent of the interpretation related to the fundamental processes. 2. Vmax cannot be exclusively regarded as a function of the rate of cross-bridge movements, but is influenced by the Ca2+-concentration and consequently by the conditions of electromechanical coupling. 3. Vmax is not a reliable measure for myocardial power capacity under all conditions as this value on the one hand and the developed tension on the other are influenced to different degrees. 4. If the amount of contractile material per cross sectional unit is changed (changed relation of fibrils/mitochondria), Vmax can give better indications on the contractile elementary process than the developed tension. 5. Increased content of connective tissue and scars influence both the developed tension and Vmax. 6. A reduction in Vmax under long-term increased hemodynamic loading of the heart is not to be considered a priori as an expression of cellular damage.

Animals↗
PubMed1978

Plasma zinc and copper in obesity and after intestinal bypass.

Plasma concentrations of zinc and copper were measured in 15 obese patients before intestinal bypass surgery, in 27 patients after intestinal bypass surgery, and in 52 lean control subjects. Preoperatively, the obese patients had zinc concentrations that were significantly lower than in the lean control subjects (76 +/- 3 versus 89 +/- 2 microgram/dl) (+/- SEM) and copper levels that were significantly higher (147 +/- 10 versus 119 +/- 3 microgram/dl). After intestinal bypass, plasma zinc and copper concentrations were significantly lower (zinc, 62 +/- 2 microgram/dl; copper, 90 +/- 5 microgram/dl; P less than 0.001) than in prebypass patients. One patient developed leukopenia associated with a plasma copper concentration of 36 microgram/dl. Leukocyte count and plasma copper level rose with oral copper sulfate replacement therapy. Intestinal bypass surgery may produce clinically significant decreases in plasma concentrations of zinc and copper. Careful observation and replacement therapy are indicated in all patients who develop deficiences after intestinal bypass surgery.

Copper↗