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Biomedical subjects

R Vargas

Publications and source records attributed to R Vargas.

At least 145 records · Page 8Linked to original sources
PubMedDate not supplied

A study of the anticholinergic activity of terfenadine in normal volunteers.

The anticholinergic effects of single doses of terfenadine, chlorpheniramine and atropine on salivary flow were compared with those of placebo in a double-blind crossover study in 21 normal adults. Salivary flow was measured immediately before administering study medications and 3 h after dosing, for the evaluation of anticholinergic activity. Mean salivary flow decreased significantly after administration of chlorpheniramine and atropine (P less than 0.01 and P less than 0.001, respectively), and was unchanged by terfenadine and placebo, indicating that terfenadine does not possess detectable anticholinergic activity. Mild drowsiness was reported by 57% and 29% of subjects who received chlorpheniramine and terfenadine, respectively.

Adult↗
PubMedDate not supplied

[Glomerulonephritis following an infected ventriculoatrial shunt. Report of 2 cases].

Two patients with shunt nephritis are reported. One of the patients had a positive blood culture to Staphylococcus albus; the kidney biopsy showed an immune complex disease. In the second patient, Klebsiella sp., was cultured in the blood, and this is the first report with such bacteria as the cause of nephritis. The finding of fibrin in the glomeruli by light, immunofluorescence and electron microsocopy studies, suggests a pathogenesis different from intravascular coagulation. In both patients, nephritis became inactive when the shunt was removed.

Cerebrospinal Fluid Shunts↗
PubMedDate not supplied

[Structural characteristics of sural nerve myelin from patients with chronic inflammatory demyelinating polyneuropathy: an X-ray diffraction study].

INTRODUCTION AND OBJECTIVE: Using the X ray diffraction technique and the mathematical analysis developed by Luzzati and Mateu, we have studied the structure of nerve myelin from patients with chronic inflammatory demyelinating polyneuropathy (CIDP) in order to quantitatively evaluate the changes occurred in the myelin sheath at structural level. PATIENTS AND METHODS: Sural nerves from 4 patients filling the criteria for CIDP were studied and the results compared to those of 4 other sural nerves extracted from patients who died in the Hospital with no symptoms of peripheral nerve diseases. The structural parameters determined by the mathematical analysis were: the repeat distance between the myelin membranes pairs (D) and its mean standard deviation (sigmaD); the mean number of membrane turns per axon ; the fraction of total myelination (alpha myel) in the nerve, the fraction of membrane pairs not packed in a crystallite (alpha loose) and the degree of disorientation (sigmaw) of the myelin membrane pairs with respect to the fiber axis. RESULTS: The alterations found in pathological nerve myelin were: 1) increase in the packing disorder sigmaD and in the fraction of disordered myelin alpha loose; 2) decrease in the percentage of myelination alpha myel and in the mean number of membrane turns around the axons . CONCLUSIONS: Our results indicate that with these techniques it is possible to detect and quantify demyelination produced by CIDP in human peripheral nerves. In consequence it should be possible to use a similar approach to study other types of polyneuropathy.

Adult↗
PubMedDate not supplied

A clinical molecular scanner: the Melanie project.

We developed an expert system to analyze and interpret protein maps. This system, Melanie (medical electrophoresis analysis interactive expert), can distinguish between normal and cirrhotic liver and identify various types of cancer on the basis of protein patterns in biopsy specimens. Our findings suggest that some diseases associated with toxic compounds or modifications of the human genome can be diagnosed by expert systems that analyze protein maps. The combination of protein mapping and computer analysis could result in a clinically useful "molecular scanner". The massive amount of information analyzed and stored in such studies requires new strategies, including centralized databases and image transmission over networks. Increased understanding of protein expression and regulation will enhance the importance of the human genome project in medicine and biology.

Computer Systems↗
PubMedDate not supplied

A double-blind comparison of transdermal clonidine and oral captopril in essential hypertension.

In a double-blind study, patients with mild essential hypertension were randomly assigned to treatment with transdermal clonidine or oral captopril. After a two- to three-week titration period, blood pressure decreased significantly from 146.3/95.4 to 134.7/85.1 mmHg in the 33 clonidine-treated patients and from 143.0/96.1 to 134.8/87.1 mmHg in the 35 captopril-treated patients; the mean daily doses were 0.2 mg (equivalent) of clonidine and 122.9 mg of captopril. After eight weeks of treatment, blood pressures were reduced to 132.9/85.2 mmHg in the clonidine group (n = 22) and 131.2/82.5 mmHg in the captopril group (n = 16). In black patients, blood pressure reductions were greater with clonidine than with captopril. Four patients were withdrawn from treatment because of side effects in the clonidine group and one in the captopril group. No between-group differences were found in the responses to a quality-of-life questionnaire completed before and after treatment. The clonidine patches were worn during 99% of patient-weeks of treatment; captopril was taken as directed during 64% of patient-weeks of treatment. It is concluded that transdermal clonidine is safe and effective and well accepted by hypertensive patients.

Administration, Cutaneous↗