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Biomedical subjects

R Melendez

Publications and source records attributed to R Melendez.

7 recordsLinked to original sources
PubMed1999

Stroke in Hispanic veterans: a descriptive study.

BACKGROUND: Differences in risk factor prevalence and distribution of atherosclerotic cerebrovascular disease have been reported among different racial-ethnic groups. Identification of stroke syndromes and risk factors specific to the Puerto Rican male population should lead to more effective diagnosis, treatment, and prevention programs. METHODS: We prospectively and consecutively evaluated 118 Hispanic male veterans admitted to our Stroke Unit from June 1994 to September 1995. RESULTS: Ninety patients (76%) had an ischemic infarct, 26 (22%) had a transient ischemic attack, and 2 (2%) had an intracerebral and/or subarachnoid hemorrhage. Hypertension was the most common risk factor. Echocardiographic studies were done in 64% of the patients, and the most common findings were concentric left ventricular hypertrophy and diastolic dysfunction. Cerebral angiography was done in 40 cases, and findings were abnormal in 32 (80%). CONCLUSIONS: We believe this is the largest descriptive study of Hispanic male veterans with stroke syndromes. It provides baseline data to serve as a comparison group for future research.

Adult↗
PubMed1997

Initial screening for antituberculous drug resistance at an inpatient facility in Leon, Nicaragua.

Antituberculous (anti-TB) drug resistance has become a major tuberculosis control issue in the United States, where this situation has closely paralleled the current acquired immunodeficiency syndrome epidemic associated with human immunodeficiency virus type-1 (HIV-1) infections. In less developed countries, especially those like Nicaragua with an apparently low prevalence of known HIV-1 infections, less is known about the epidemiology of antituberculous drug resistance. To understand the potential extent of this problem in Nicaragua, we conducted a cross-sectional prevalence study at Nicaragua's only inpatient tuberculosis treatment facility, located in Leon, Nicaragua. A radiometric method was used during recovery, purification, and drug susceptibility testing of clinical Mycobacterium tuberculosis isolates. Resistance to at least one of the major anti-TB medications was found in 15 (40.5%) of 37 sputum isolates, of which seven (19%) were resistant to either isoniazid alone, or to isoniazid plus another agent other than rifampin. Five were resistant to at least isoniazid and rifampin (i.e., 13.5% demonstrated multidrug resistance). Two isolates were resistant to pyrazinamide alone, and one was resistant to streptomycin alone. These initial results suggest that anti-TB drug resistance is a defined problem for tuberculosis control programs in Nicaragua, a problem that is largely related to individual noncompliance, lack of extensive drug susceptibility testing facilities, and a general unavailability of expensive anti-TB medications for re-treatment. Ongoing surveillance for drug resistance, using the methodology presented here, might assist Nicaraguan public health officials in their tuberculosis control programs.

Adult↗
PubMed1990

Pharmacokinetics of intravenously, intramuscularly and intra-adiposely administered carazolol in pigs.

The beta-blocking agent carazolol is used for the prevention of stress syndromes in pigs. Little is known of the pharmacokinetics of this drug, and therefore of its residue status in meat. In this study carazolol pharmacokinetics were investigated in a randomized three-way cross-over design in five pigs. A dose of 0.025 mg/kg was given intravenously, intramuscularly and intra-adiposely (in the subcutaneous fat layer). Carazolol was rapidly distributed and had a short half-life of 1.2-4.2 h. The distribution volume was calculated to be 0.22-0.65 l/kg. After intramuscular or intra-adipose administration the absorption pattern was biphasic. A rapid initial phase was followed by a slow second phase. Absorption was found to be incomplete at 24 h after intramuscular and intra-adipose administration ranging from 24 to 59% and 25 to 66%, respectively. The biphasic behaviour could be explained by retention of the drug in the tissues after absorption of the solvent was complete. A few hours after intravenous administration only negligible amounts of the drug were circulating in the body; however, considerable amounts of drug might have remained at the intramuscular or intra-adipose injection site.

Adipose Tissue↗
PubMed1989

Rectal prolapse caused by blunt abdominal trauma.

We describe a case of incarcerated rectal prolapse caused by blunt abdominal trauma. Emergency treatment consisted of manual reduction with the patient under general anesthesia, proctosigmoidoscopy, and peritoneal lavage. Subsequent definitive surgical therapy was then performed after bowel preparation and consisted of anterior resection of the sigmoid colon with posterior (sacral) rectopexy.

Abdominal Injuries↗
PubMed1985

Seroepidemiology of bovine anaplasmosis and babesiosis in Venezuela.

The serological prevalence of bovine anaplasmosis and babesiosis in the Centro-Occidental region of Venezuela was determined using the indirect fluorescent antibody (IFA) and latex agglutination (LAT) tests. Anaplasma marginale IFA and LAT prevalence rates were 57.7 and 48.6% respectively for cattle of all ages and breeds. The respective prevalence of IFA activity to B. bigemina and B. bovis was 78.2 and 38.8%. The LAT test specific only for Babesia spp. revealed that 61.4% of the animals tested were serologically positive for Babesia parasites. Anaplasma marginale and B. bigemina organisms were detected in peripheral blood smears of 21.1 and 7.5% respectively of cattle surveyed. A longitudinal survey of antibody activity and incidence of parasitaemia for Anaplasma and Babesia infections was conducted in two groups of calves from their birth to seven months of age. The animals generally experienced infections between three and four months of age the period subsequent to decline in colostral antibody levels. Seroepidemiological data are considered in the formulation of proposed vaccination regimens for anaplasmosis and babesiosis.

Anaplasmosis↗
PubMed1984

Gastric function before and after gastric sympathectomy and subsequent truncal vagotomy.

A surgical technique for selective gastric sympathectomy (SGS) has been developed by total devascularization of the dog stomach with immediate revascularization via the divided and reanastomosed splenic artery and vein. Splenectomy is also performed to divert the entire splenic blood-flow to the stomach. Several months later biopsy of vessels from the gastric wall shows that all catecholamine staining is lost. Blood-flow studies using the aminopyrine clearance method show that a significant decrease in blood-flow occurs, particularly during maximal acid secretion. The effects of SGS on the gastric acid responses of 5 dogs were: (1) increased responsiveness to histamine with a left shift of the dose-response curve (D50 = 35 +/- 5 before, and 17 +/- 4 micrograms kg-1 hr-1 after; p less than 0.05); (2) increased response to insulin hypoglycemia (peak 15 min output = 3.5 +/- 0.9 before, and 5.5 +/- 0.9 mMol after; p less than 0.05); but (3) a reduction of acid response to meal (peak 15 min output = 7.1 +/- 0.9 before, 3.7 +/- 1 after; p less than 0.05). Propranolol, on the other hand, had no effect on the response to meal before SGS but enhanced it after SGS restoring the response to pre-SGS levels. Subsequent vagotomy abolished acid response to insulin but did not alter the post-SGS response to a meal. We conclude that the sympathetics exert a beta-adrenergic inhibitory influence on gastric acid response to insulin and histamine but not to food. Following SGS, the enhancing effect of propranolol probably implies supersensitivity of the stomach to circulating catecholamines.

Animals↗