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Biomedical subjects

C Rodriguez

Publications and source records attributed to C Rodriguez.

At least 181 records · Page 10Linked to original sources

Purification and partial characterization of an antibiotic produced by Myxococcus coralloides.

A strain of Myxococcus coralloides producing an antibiotic capable of inhibiting growth of Gram-positive bacteria was isolated. Antibiotic production occurred during vegetative growth but not during myxospore formation. The antibiotic was extracted from the growth medium with chloroform and purified by adsorption on silicic acid and by preparative silica gel thin-layer chromatography. The purified antibiotic showed a resistance to heat, acid, alkali and proteolytic enzymes. Chromatographic and electrophoretic behavior as well as infrared, ultraviolet and mass spectra are presented.

Anti-Bacterial Agents

Biological activity of an antibiotic produced by Myxococcus coralloides.

A strain of Myxococcus coralloides was isolated which produced an antibiotic active against Gram-positive bacteria and also against Neisseria sp at high levels of antibiotic. The antibiotic was bactericidal on sensitive growing bacteria. It was inactive on non-growing cells and also on cells whose growth has been stopped by addition of chloramphenicol. Strains of S. aureus resistant to several antibiotics, including penicillin and ampicillin, were also sensitive to this antibiotic.

Anti-Bacterial Agents

Digital interface for bioelectrical data acquisition system.

The action potential digitalized and stored by means of a fast solid state electronic waveform recording system (Digitalizer) can be directly read out on a printer or in a computer for further processing. It has been designed a digital interface allowing the automatization of these bioelectrical data acquisition and printing process.

Action Potentials

[Articular and muscular manifestations of bacterial endocarditis. 11 cases (author's transl)].

We report 11 cases of bacterial endocarditis with muscular and articular manifestations seen over the past ten years. There was arthralgia in 7 cases, vertebral pain in 7 cases and myalgia in 3 cases. Arthritis consisted of a monoarthritis of the ankle in 2 cases and oligoarthritis in 2 cases. There were also 2 cases of lumbar spondylodiscitis and 1 of finger clubbing in the series. The underlying heart disease was a valvular lesion of the left side of the heart in 10 cases out of 11 and the organism isolated by blood culture was a streptococcus in 9 cases and a staphylococcus in 11. We emphasis the need for early diagnosis and appropriate antibiotic therapy, in the absence of which the course may be fatal in the short term, as it was the case in one of our own patients.

Adult

Effects of cloprednol and other corticosteroids on hypothalamic-pituitary-adrenal axis function.

The effects of cloprednol and other corticosteroids on hypothalamic-pituitary-adrenal (HPA) function were studied in healthy subjects after administration of a single oral dose of corticosteroid at 6 a.m. or 6 p.m., and after daily 6 a.m. administration of corticosteroids at various doses for seven days. The degree of HPA suppression was assessed by metyrapone tests (METP), insulin hypoglycaemia tests (IHT) and 6 a.m. fasting plasma cortisol concentrations. Regardless of the corticosteroid tested, 6 p.m. dosing was at least four-fold more suppressive of METP response than 6 a.m. administration. At therapeutically equivalent doses, single doses of triamcinolone and dexamethasone were more suppressive of HPA-axis function than cloprednol, hydrocortisone or prednisolone, After 6 a.m. administration for seven days, 12-5 mg of cloprednol did not impair the cortisol response to IHT or interfere with the METP response. The clinically equivalent dose of prednisolone (25 mg) resulted in slightly greater HPA-axis suppression. All doses of dexamethasone (0-5, 3-75 and 6-0 mg) and of betamethasome (2-0, 4-0 and 6-5 mg) were more suppressive of HPA-axis function than either cloprednol or prednisolone. These results suggest that at equipotent anti-inflammatory doses, cloprednol is slightly less suppressive of HPA-axis function than prednisolone, and both cloprednol and prednisolone are much less suppressive than dexamethasone or betamethasone.

Adolescent

Intrathoracic ectopic kidney: report of a case.

A case of intrathoracic ectopic kidney is reported and the literature is reviewed. Intrathoracic ectopic kidney is a rare developmental anomaly. The surgeon should be fully aware of this anomaly in order to make a correct diagnosis before an ill-advised thoracotomy is performed.

Adult

Metabolic effects of cloprednol-a new systemic corticosteroid.

The short-term metabolic effects of cloprednol, a new short-acting synthetic corticosteroid, were evaluated in four normal subjects. Cloprednol, 12.5 mg/day, in one subject had no appreciable effect on urinary excretion of sodium, potassium, nitrogen, or calcium. Cloprednol, 20 mg/day, in three subjects had no significant effect on mean daily urinary sodium and potassium excretion, although mild, transient sodium retention and kaliuresis were observed. One subject had increased nitrogen excretion and all three had a small increase in calcium excretion. Prednisolone, 40 mg/day, a dose with antiinflammatory potency equivalent to 20 mg/day cloprednol, given subsequently to two subjects under identical conditions resulted in sodium and potassium excretion results similar to those of cloprednol, 20 mg/day, but produced a much greater increase in nitrogen and calcium excretion. These results suggest that, like prednisolone, cloprednol lacks the sodium-retaining properties of hydrocortisone and raise the possibility that cloprednol has less of a deleterious effect on nitrogen and calcium excretion than prednisolone.

Adult

Endocarditis due to ampicillin-resistant nontyphoid Salmonella: cure with a third-generation cephalosporin.

A case of ampicillin-resistant salmonella bacteremia complicated by endocarditis in a 78-year-old man is presented. Previous rheumatic valvular heart disease and the lack of response to initial treatment with chloramphenicol prompted us to consider this diagnosis. There was a good clinical response after treatment with ceftriaxone alone and corresponding improvement on the echocardiogram. This case demonstrates the possible endovascular complications of salmonella bacteremia in elderly people and that endocarditis should be included among the invasive infections due to ampicillin-resistant Salmonella that could potentially be treated with the newer cephalosporins.

Aged

Attenuated nocturnal rise in pineal and serum melatonin in a genetically cardiomyopathic Syrian hamster with a deficient calcium pump.

Day and nighttime melatonin production in the pineal gland was compared in normal and cardiomyopathic (polydystrophic) adult male Syrian hamsters. These strains of hamsters were selected for comparison because the cardiomyopathetic hamster displays a deficient transmembrane Ca(2+)-pump in a number of tissues, and intracellular CA2+ concentrations ([Ca2+]i) play a central role in the nocturnal increase in pineal melatonin synthesis. Daytime levels of all constituents measured, i.e., pineal N-acetyltransferase (NAT) activity, pineal and serum melatonin levels, and pineal 5-hydroxytryptophan (5-HTP), serotonin, and 5-hydroxyindole acetic acid (5-HIAA) contents, were comparable in control and dystrophic hamsters. In contrast, the nighttime rises in pineal NAT activity and pineal and serum melatonin levels were significantly attenuated in the dystrophic hamsters. By comparison, the pineal contents of 5-HTP, serotonin, and 5-HIAA were essentially the same in both groups of hamsters with both pineal serotonin and 5-HIAA values exhibiting the usual nighttime drop. It is presumed that the alterations in nocturnal melatonin production in the pineal gland of the cardiomyopathic hamster may relate to a generalized deficiency in the Ca(2+)-pump in pinealocyte plasma membranes, which leads to unusually high [Ca2+]i, causing a depression of NAT activity; this leads to the commensurate decline in pineal and serum melatonin levels. Harderian gland NAT activity and melatonin levels were essentially similar in the two groups of animals, although NAT activity was slightly depressed in the dystrophic hamsters killed during the day. The reduced amounts of intrascapular brown fat in the cardiomyopathic hamster is speculated to be a result of the diminished amount of melatonin produced in these animals.

Animals