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Biomedical subjects

H Vélez

Publications and source records attributed to H Vélez.

At least 19 recordsLinked to original sources
PubMed2000

Synthesis of (Z)-2-(2-formamido-4-thiazolyl)-2-(substituted alkoxyimino) acetic acids.

(Z)-2-(2-formamido-4-thiazolyl)-2-(substituted alkoxyimino) acetic acids were synthesized by a new method based on the following sequence of reactions: treatment of the tert-butyl acetoacetate with sodium nitrite, alkylation of the oxime formed with an appropriate alkyl halide, halogenation of methyl alpha-keto group and simultaneous cleavage of tert-butyl ester with sulfuryl chloride, protection of the obtained acid function with diphenyldiazomethane, formation of the 2-aminothiazole ring by the Hantzsch method with thiourea, formylation of the amino group and selective final cleavage of the diphenylmethyl ester by treatment with trifluoroacetic acid and anisol. The developed procedure allows the synthesis of (Z)-2-(2-formamido-4-thiazolyl)-2-(substituted alkoxyimino) acetic acids, with an ester function in the alkoxyimino group employing a simple method and obtaining higher yields in comparison with the habitually used classic method.

Acetates↗
PubMed1999

[Health status and functional limitations in the elderly population of the University Region of Health of Puerto Rico: methodologic aspects and prevalence estimates].

In order to plan the health services for the elderly population, it is necessary to quantify their health status and their functional capacity. In Puerto Rico, few epidemiological studies have been conducted regarding functional capacity and chronic diseases in the elderly population. One of the difficulties to undertake these studies is the high cost and risks to move this population for clinical exams, in addition to the methodology limitation of self-report in the elderly population. This study shows the use of logistic regression to estimate the prevalence of chronic diseases and functional capacity, when the observed data are not consisted with the planed sampling scheme. Four hundred and eighty-seven elderly persons (65 yr. and over) were interviewed in the municipalities of Canóvanas, Carolina, Loíza and Trujillo Alto in Puerto Rico, using a cross-sectional design. More than half of the elderly had visual problems (IC 95%: 54.8%, 63.8%), arthritis (IC 95%: 52.7%, 61.5%) and hypertension (IC 95%: 47.3%, 56.3%). In the case of hypertension, significant differences (p < 0.05) by sex were observed, where women reported a higher prevalence than men. One of the higher prevalences in the functional capacity status was with urine accidents. More than one-third of the population is estimated to have this problem (IC 95%: 34.7%, 43.4%). One-fourth of the population had limitations with going out for shopping (IC 95%: 23.9%, 31.9%) and using public and private transportation (IC 95%: 19.5%, 26.9%). We conclude that the applied methodology was consistent with the estimation presented in the literature and statistics from the Puerto Rico Health Department. However, it is necessary to continue assessing the design and analytical methodology, in order to undertake consistent and periodic evaluations of the elderly population.

Activities of Daily Living↗
PubMed1989

Isolation and characterization of an antitumor active agar-type polysaccharide of Gracilaria dominguensis.

Cold water extraction of the red alga Gracilaria dominguensis, followed by cetyltrimethylammonium bromide fractionation, gave a highly sulfated, agar-type polysaccharide which inhibited the transplantation of Ehrlich ascites carcinoma in mice. The structure of the polysaccharide has been investigated by methylation analysis, and 1H- and 13C-n.m.r. spectroscopy, and was shown to be mainly composed of alternating (1----3)-linked beta-D-galactopyranosyl 6-sulfate and (1----4)-linked 3,6-anhydro-alpha-L-galactopyranosyl residues.

Animals↗
PubMed1985

Onychomycosis due to saprophytic fungi. Report of 25 cases.

Twenty five cases of onychomycosis due to filamentous saprophytic agents were diagnosed within the period 1981-1982 in two mycology laboratories in Medellín, Colombia. These cases represented 4.5% and 9.5% respectively of the total fungal nail lesions (FNL) seen at those institutions. No explanation was found for the high frequencies, which sharply contrast with the previous local experience with the disease (0.4% of FNL). The responsible agents belonged to the following genera in decreasing order of frequency: Fusarium, Aspergillus, Scopulariopsis, Penicillium and Lasiodiplodia; two patients were infected with unidentified dematiaceous fungi and two more had the association of a saprophyte and a dermatophyte. In every case direct KOH preparations revealed septate hyphae, associated in 14 patients (56%) with chlamydoconidia. The only predisposing factors that were common to all these patients were age above 20 years and the use of footwear.

Adult↗
PubMed1978

Immune responses in paracoccidioidomycosis. A controlled study of 16 patients before and after treatment.

Serum electrophoresis patterns and various measures of specific and non-specific immune competence were determined in 16 patients with paracoccidioidomycosis, at time of diagnosis and 6 months after therapy. The results were compared with those furnished by the study of 16 control subjects, matched by age and sex. Once treated, the patients approached normality in some parameters. Untreated patients had significantly diminished albumin levels with increased alpha 1, alpha 2 and gamma fractions. Immune gamma globulin G (IgG) was elevated and remained so during therapy. Both before and after treatment patients had diminished total numbers and decreased percentages of E rosettes; they also had depressed lymphocyte transformation with phytohemagglutinin (PHA) and paracoccidioidin (P). Also, untreated patients exhibited the lowest skin test responses to PHA, purified protein derivative (PPD), P and candidin (C); significant differences, however, were limited to the former 2 antigens. All untreated patients had detectable antibody titers against P. brasiliensis; these titers had a tendency to drop during treatment. No direct correlation was found between elevated serum fractions, presence of antibodies and depressed cellular immunity.

Adolescent↗
PubMed1975

[Effect of phagocytosis in vitro on Paracoccidioides brasiliensis].

Peripheral leukocytes from 17 patients with paracoccidioidomycosis were mixed with yeast cells from Paracoccidioides brasiliensis and Rhodotorula sp. to ascertain their phagocytic and lytic capacities. The role of circulating antibodies in the process was also investigated by the use of autologous serum. The phagocytic capacity of the leukocytes was found to be normal for both types of yeasts. However, in the presence of the patient's serum, the percentage of P. brasiliensis cells ingested was increased (P smaller than or equql to 0.02). Furthermore, in 70-5% of the cases the lytic process was increased and more P. brasiliensis cells were killed when such a serum was employed (P smaller than or equal to 0.0013). This increased effect was not recorded for Rhodotorula sp. cells, thus indicating specificity. The peripheral leukocytes from patients with paracoccidioidomycosis are not defective. However, the success of the phagocytic process is aided by the opsonic action of the specific antibodies in the patient's serum.

ABO Blood-Group System↗