A multicompartment pharmacokinetic model is presented to describe procaine distribution in humans during and following intravenous infusion. The model, based on a general perfusion model, relates individual characteristics such as sex, age, weight, height, infusion rate and duration, and hematocrit to general parameters such as drug metabolism, protein binding, ion-trapping effects, and tissue-plasma distribution coefficients to provide an individualized distribution prediction. Experimentally observed kinetics of blood procaine levels collected during intravenous procaine infusion as an adjunct to surgical anesthesia and blood lidocaine levels obtained from the literature compared very well with the model simulation.

Humans↗

PubMed1979

Plasma catecholamines and blood pressure responses to the carotid baroreceptor reflex in essential hypertension.

1. Slight decreases and increases in carotid baroreceptor activity were induced in subjects with essential hypertension by slight alterations in carotid transmural pressure (variable pressure neck-chamber technique) in order to obtain limited increases and reductions in sympathetic adrenergic activity. 2. When sympathetic activity was reflexly increased there was a rise in arterial pressure but no significant increase in plasma catecholamines. Likewise when sympathetic activity was reflexly reduced there was a fall in arterial pressure but no significant reduction in plasma catecholamines. 3. Plasma noradrenaline and adrenaline significantly and markedly increased in the same subjects when sympathetic activity was increased by activation of both arterial and low pressure baroreceptor reflexes with tilting. 4. It is suggested that measurements of catecholamines in systemic plasma may reveal marked degrees of sympathetic activation but may not be a sensitive index of more moderate changes in sympathetic tone.

Adult↗

PubMed1979

Selective endoscopic contrastography (S.E.C.): an original association of radiology and endoscopy of the small and large intestine.

A more complete diagnostic information can be obtained by "carrying" the contrast medium through the fibercoloscope to those sites of the bowel where neither radiology alone nor endoscopy alone succeed in solving the diagnostic problem. The indications for a selective perendoscopic contrast study during coloscopy are few, but well defined and certainly not negligible:--demonstration and assessment of stenoses (unclarified by radiology and endoscopy);--accurate evaluation of the last ileal loop;--diagnostic study of ileo-colic surgical anastomoses;--fistulous tracts. Seventy-six patients were examined, without complications. The method proved useful in 42% of cases, conclusive in 33%, useless or inconclusive in 17%, unsuccessful in 8% (technical difficulties). On this basis, selective endoscopic contrastography is considered of use whenever its specific indications apply.

Constriction, Pathologic↗

PubMed1979

Fiberendoscopic evaluation of ureterosigmoidostomies.

Sixteen patients having undergone ureterosigmoidostomy have been examined using fiberoptic coloscopes. Morphology and function of both the colonic mucosa and the ureteral stumps have been evaluated by direct observation, biopsy brush cytology and i.v. injection of methylen blue. The obtained encouraging results point to this fiberendoscopic diagnostic approach as an easy and useful follow-up examination of patients with intestinal urinary diversions.

Adult↗

PubMed1979

Indole-3-lactic acid as a tryptophan metabolite produced by Bifidobacterium spp.

Fifty-one strains of the genus Bifidobacterium have been found to accumulate indole-3-lactic acid in culture broth. The isolated metabolite was identified through mass and nuclear magnetic resonance spectroscopy. All the microorganisms tested, as resting cells, have been shown to be able to convert L-tryptophan into L-indole-3-lactic acid.

Actinomycetaceae↗

PubMed1979

Baroreceptor control of atrioventricular conduction in man.

Although human baroreflexes are known to exert a powerful physiological control on heart rate, little information exists on the physiological control they exert on the atrioventricular conduction system. In 11 normotensive subjects with normal atrioventricular conduction, we altered baroreceptor activity by injection of pressor and depressor drugs (phenylephrine and trinitroglycerin) and recorded mean arterial pressure (MAP, catheter measurements), R-R interval, and pre-His and post-His intervals (A-H and H-V, His bundle recording). With the subjects in sinus rhythm, increasing MAP by 21+/- 1 mm Hg caused a marked lengthening (250 +/- 28 msec), and decreasing MAP by 17 +/- 2 mm Hg a marked shortening (142 +/- 16 msec) of the R-R interval. There was little change in the A-H interval and no change at all in the H-V interval. However, when the R-R interval was kept constant in these subjects by atrial pacing, a similar increase and decrease in MAP caused, respectively, a marked lengthening (49 +/- 6 msec) and shortening (19 +/- 3 msec) of the A-H interval, although the H-V interval remained unaffected. Thus physiological ranges of baroreceptor activation have a marked influence on the atrioventricular node but apparently not on the ventricular portion of the atrioventricular conduction system. This influence is unmasked when pacing prevents the baroreceptor influence on the sinoatrial node.

Adult↗

PubMed1979

[7-Alpha dehydroxylation of bile acids by O2-intolerant anaerobic intestinal microorganisms].

The 7 alpha-dehydroxylation of cholic and chenodeoxycholic acids by mice intestinal microorganisms was studied. When all techniques, from autopsy of the animals to final incubation, are performed in oxygen-free environment, it has been found that anaerobic O2 non tolerant microorganisms might be considered the main responsible for these transformations.

Anaerobiosis↗

PubMed1978

Baroreceptor reflexes in human hypertension.

We studied the control of arterial pressure by the carotid sinus baroreceptors in 35 hypertensive humans, using a variable pressure neck chamber to alter carotid sinus transmural pressure in a graded fashion. The results were compared with those obtained from 11 normotensives. As in normotensives, reduction in carotid transmural pressure caused a linearly related pressor response and vice versa. However, whereas in normotensives the pressure response was greater than the depressor, the reverse was the case in hypertensives. Furthermore, the pressor response decreased and the depressor response increased progressively with an increase in severity of the hypertension. Thus while in normotensives the carotid baroreflex is more effective in protecting against hypotension, in hypertensives the antihypertensive function of the reflex is favored. Similar differences between hypertensives and normotensives were found with respect to the carotid baroreceptor control of heart rate. In eight hypertensives, reflex changes in heart rate also were studied by injection of phenylephrine and trinitroglycerine to vary not only carotid baroreceptor activity, but also activity of extracarotid baroreceptors. The results were compared with results of similar studies on eight normotensives. These comparisons suggest that, whereas the carotid baroreceptor reflex remains active in hypertension, reflexes stemming from extracarotid baroreceptor areas are much diminished.

Adult↗

PubMed1977

Activity on bile acids of a Clostridium bifermentans cell-free extract.

Explore the source record for details and available documents.

Bile Acids and Salts↗

PubMed1977

On the mechanism of cholic acid 7alpha-dehydroxylation by a Clostridium bifermentans cell-free extract.

Explore the source record for details and available documents.

Cell-Free System↗

PubMed1977

Low-dose combination oral contraceptives: a controlled clinical study of three different norgestrel-ethinyl estradiol ratios.

Three doses of norgestrel-ethinyl estradiol in altered ratios were investigated in a double-blind, randomized study. The estrogen content was maintained at 20 microng or less, while the progestogen dose was increased in 100-microng increments. Two pregnancies were reported for the lowest dose. No pregnancies occurred in the two higher doses. Each dosage increase improved cycle control and lessened bleeding irregularities. The incidence of patients reporting intermenstrual bleeding was inversely proportional to the doses studied. Dropouts for cycle disturbances followed a similar pattern.

Adult↗

PubMed1977

The variable-pressure neck-chamber method for studying the carotid baroreflex in man.

1. The variable-pressure neck-chamber method was analysed in ten healthy volunteer subjects to determine its suitability for the study of the carotid baroreceptor reflex in man. 2. Positive and negative pressures applied to the neck (range +/- 60 mmHg) were always transmitted linearly to a tissue catheter outside the carotid sinus, but only 86% of positive pressure, and 64% of negative pressure. Tissue pressures were confirmed by simultaneous measurement in the internal jugular vein adjacent to the carotid sinus. 3. Positive and negative pressure changes within the above range did not alter PO2 of internal jugular venous blood, suggesting that cerebral blood flow was unaltered. 4. Positive pressure changes induced reflex pressor responses of similar magnitude at arterial PO2 12-8 and 70-1 kPa (96 and 527 mmHg), suggesting that the carotid chemoreceptors were not involved. 5. It is concluded that the variable-pressure neck chamber is a valid method for selectively studying the carotid baroreceptor reflex in man. However, transmission of external pneumatic pressure to the carotid sinus is imperfect and greater for positive than for negative pressure. This must be recognized to avoid underestimation of gain and distortion of shape of the reflex.

Adult↗