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Biomedical subjects

A Ramírez

Publications and source records attributed to A Ramírez.

At least 91 records · Page 5Linked to original sources
PubMed1993

[Bacteremia caused by Mycobacterium tuberculosis and/or Mycobacterium avium detected by the non-radiometric Bactec system].

BACKGROUND: To assess the utility of Bactec non-radiometric system in detecting disseminated mycobacteremia. METHODS: Blood cultures are processed using the Bactec NR 660/HPS system. Incubation of the NR6A vials, from HIV infected patients, is prolonged for 6 weeks and read once a week. After the 14th day of incubation a growth value > or = 30 is considered positive. RESULTS: Mycobacteria were recovered from 80 blood cultures from 32 human immunodeficiency virus infected patients. The mean time required to detect growth was 37.8 days (range 20-45). Mycobacterium tuberculosis was isolated from 18 patients and Mycobacterium avium from 14. In 12 patients (37.5%) blood culture was the first or the only positive specimen. CONCLUSIONS: Prolonged incubation of NR6A medium has proved to be a suitable method for detecting mycobacteremia.

Adult↗
PubMed1993

[Serum prolactin during oral metoclopramide in normal nulliparous women].

As a first step in an extensive project planned to determine serum PRL levels in response to oral metoclopramide in women with a diverse gyneco-obstetric history, it was decided to study 51 clinically healthy nulliparous women, aged 15.8 to 48.2 years, with history of regular menses at least one year before the study (except the three postmenopausal women), with no regular drug ingestion during the last six months. Women were studied on days 18 to 22 of menstrual period, after a 30 minute rest on basal conditions (3 samples) at 60, 90, and 120 minutes after a single 10 mg. oral dose of metoclopramide. Duplicate PRL determinations were performed in all samples and progesterone(P) only in a pool of the three basal samples by radioimmunoanalysis. All women had serum P levels > or = 4.0 ng/ml. A significant linear positive correlation (r > or = 0.6795, p < 0.001) was observed between chronologic age (CA) and serum PRL levels, regardless the way they were expressed. Considering the individual responses it was decided to divide the group according to CA and it was observed that serum PRL levels--expressed in any form were always significantly greater in women aged > 25 years (Group 2) in contrast with women aged < or = 25 years (Group 1). Since differences were evident, percentiles 3, 50 and 97 for serum PRL levels were calculated during each test time for both groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1992

Esophageal atresia and tracheoesophageal fistula in two infants born to hyperthyroid women receiving methimazole (Tapazol) during pregnancy.

We report on 2 newborn infants with esophageal atresia and tracheoesophageal fistula (EA + TEF) born to hyperthyroid mothers receiving methimazole (Tapazol) before and during their entire pregnancies. Both mothers were euthyroid during gestation and developed hydramnios diagnosed during weeks 34 and 33 of gestation. Premature delivery (36.2 weeks of gestation) occurred in one case, and both newborn infants were small for date with palpable goiter; one of them had other associated malformations. Hypothyroidism was diagnosed by laboratory tests in both cases. Corrective surgery was undertaken, but both newborn infants developed septicemia and renal insufficiency and died in the first week of life. The EA + TEF and a normally placed enlarged thyroid gland were confirmed at necropsy. These cases represent a previously unreported example of the association of maternal ingestion of methimazole during pregnancy and EA + TEF.

Abnormalities, Drug-Induced↗
PubMed1992

A rapid colorimetric assay with the tetrazolium salt MTT and phenazine methosulfate (PMS) for viability of Entamoeba histolytica.

A rapid colorimetric assay for viability of E. histolytica trophozoites using the tetrazolium salt MTT and phenazine methosulfate (PMS) was developed. The MTT is normally reduced by dehydrogenases of viable cells and transformed to formazan, a colored compound; the reaction is catalyzed by PMS. Trophozoites of E. histolytica were incubated in the presence of MTT and PMS during 15, 30, 45, 60 and 75 min, at 37 degrees C. Trophozoites killed by heat or cold were used as controls. The formazan produced into the cells was extracted with isopropanol-HCl and the optical density (OD) was measured at 570 nm. There was a linear relation between the number of viable trophozoites and the OD570 (r2 = 0.98). The trophozoites killed by cold or heat did not reduce MTT. The optimal time of incubation with MTT/PMS was 45 min. The MTT/PMS assay for determining viability of E. histolytica trophozoites is reproducible, rapid and easy to perform and it could be useful to study cytotoxicity and susceptibility to drugs.

Animals↗
PubMed1992

Macrophage colony-stimulating factor enhances the respiratory burst of human monocytes in response to Entamoeba histolytica.

Mononuclear phagocytes (MP) are probably the most capable effector cells of the body in the defense against virulent strains of E. histolytica. Killing of E. histolytica by MP appears to involve both oxidative and non-oxidative mechanisms. Thus, in this study we have investigated whether trophozoites of an axenic virulent strain E. histolytica HM1:IMSS (EH) were capable of eliciting an oxidative response in pure populations of freshly isolated human monocytes. Using a luminol-enhanced chemiluminescence assay we demonstrate that these cells produce a strong respiratory burst when challenged with live amebas over a wide range of MP:EH ratios. Furthermore, pre-incubation of monocytes with recombinant Macrophage Colony Stimulating Factor (M-CSF) could further increase the oxidative metabolism of MP in response to E. histolytica. Our results indicate that, in contrast to what occurs with polymorphonuclear leukocytes, the interaction of E. histolytica with MP leads to the production of reactive oxygen intermediates by this cells. The enhancement of this potent microbicidal mechanism by inflammatory cytokines may further increase the amebicidal capacity of human mononuclear phagocytes.

Adult↗
PubMed1992

Effects of albendazole on Entamoeba histolytica and Giardia lamblia trophozoites.

Albendazole, a benzimidazole carbamate commonly used for the treatment and control of intestinal helminthic infections, is also useful for the treatment of giardiasis. Therefore, it is of interest to determine whether the drug has activity against other intestinal protozoa, such as E. histolytica. The present results demonstrate that albendazole inhibits the growth of E. histolytica trophozoites in axenic cultures and induces fine structural changes such as polyribosome aggregation and loss of cytoplasmic vacuoles at concentrations up to 10 micrograms/ml. The viability of E. histolytica trophozoites was not affected by the drug. In contrast, lower concentrations of albendazole showed dramatic effects on G. lamblia trophozoites. These included loss of adhesiveness, striking modifications of the overall morphology of giardias, disassembly of the ventral disk, and loss of viability after prolonged treatment. The results provide further evidence on the potent antigiardial activity of albendazole and indicate that, at the concentrations used, the drug has no antiamebic activity.

Albendazole↗
PubMed1992

[Angiographic findings in non-Q wave infarction and their relation to ST-T changes].

Non q wave myocardial infarction has been attributed to occlusion of a vessel with no ECG representation, early reperfusion of the occluded artery or occlusion of a vessel with generous collateral flow. The coronary arteriography of 84 patients with non Q wave myocardial infarction performed at 16 + 17 (SD) days after infarction was analyzed. Main left lesion was found in 6 (17%), single vessel disease in 30 (36%), two vessel disease in 18 (24%) and 3 vessel disease in 16 (19%). The "culprit" vessel had a critical residual lesion in 38 patients (45%): 22 affected the left anterior descending artery, 10 the circumflex, and 5 the right coronary artery. No residual lesion was found in 10 patients (12%). An occluded artery was found in 32 patients (38%): circumflex in 20, right coronary artery in 9 and left anterior descending in 3 (p < 0.01). Significant collateral flow to the occluded vessel was present in 41% of cases. The ST segment was analyzed in 82 patients. Depression of ST was found in 29 (35%), elevation in 22 (27%), negative T waves in 17 (21%) and minimal alterations in 17%. There was no correlation between ST levels and coronary occlusion of the culprit artery. Depression of ST was more commonly (p < 0.01) associated with severe coronary artery disease (main left or 3 vessel disease), which may be related to the poorer prognosis in these cases.

Adult↗
PubMed1991

Basal and metoclopramide-stimulated prolactin (PRL) serum levels in users and non-users of a copper intrauterine device (TCu-380 IUD).

The study was undertaken to analyze the basal and metoclopramide-stimulated serum PRL levels in healthy parous women users (group 1, n = 12) and non-users (group 2, n = 12) of a TCu-380 IUD. All women had regular menses and were studied between days 18 to 22 of their cycle; none had lactated nor regularly ingested any type of medication during the last six months. After a 10-12 hour overnight fast, peripheral venous blood samples were obtained through an indwelling catheter at -30, -15 and 0 minutes and at 60, 90 and 120 minutes after oral metoclopramide (10 mg). There were no significant differences in serum PRL between both groups, in basal levels nor throughout the test, whether analyzing the mean values at each sampling time, the sum of PRL levels from 60-120 minutes, or the peak levels. No correlation was observed between PRL levels and any of the clinical or obstetric characteristics of the women in both groups. Serum progesterone was greater than or equal to 4.0 ng/ml in all women. Thus, the use of alpha TCu-380 IUD did not induce any significant changes in basal nor in stimulated serum PRL levels.

Administration, Oral↗
PubMed1991

[Massive pulmonary thromboembolism treated with selective infusion of streptokinase. Report of 2 cases].

We report 2 patients who developed massive pulmonary embolism with greater than 50% occlusion of the pulmonary arterial circulation. Hypotension, syncope and right sided failure were the clinical manifestations. Immediately after diagnostic pulmonary arteriography, 20,000 U of streptokinase (SK) were delivered in the pulmonary artery next to the thrombotic mass. A continuous infusion of SK, 10,000 U/h was maintained for 24 h in one patient and 72 h in the other. Rapid clinical improvement was observed in the following 24 h. Control angiography showed lysis of the embolus with residual obstructions of segmentary branches. The clinical value of this form of treatment for pulmonary embolism is discussed.

Adult↗
PubMed1991

[Myocardial ischemia in patients older than 70 years of age. Clinical and angiographic aspects].

We studied 77 patients with clinical suspicion of ischemic heart disease whose age ranged from 70 to 84 years. Patients with atypical angina had mostly normal coronary arteries, while those with unstable angina usually had three vessel disease or main left disease. According to the left ventricular function, surgery was considered safe in 66% of patients with unstable angina and 33% of those with stable angina. One patient developed a pseudoaneurysm at the arterial puncture site and hematomas were present in 3 other patients. Currently we try to avoid coronary arteriography in older patients with atypical angina due to its low yield.

Age Factors↗
PubMed1990

A novel functional cell surface dimer (Kp43) expressed by natural killer cells and T cell receptor-gamma/delta+ T lymphocytes. I. Inhibition of the IL-2-dependent proliferation by anti-Kp43 monoclonal antibody.

In the present study we describe a novel functional cell surface molecule, designated as Kp43, which is expressed among leukocytes by NK cells, TCR-gamma/delta + T lymphocytes, and some CD8+ CD56+TCR-alpha/beta + T cell clones. The Kp43 Ag is a 70-kDa disulfide-linked dimer, which migrates in SDS-PAGE under reducing conditions as a single 43-kDa band. Two-color immunofluorescence staining of fresh PBL revealed that only a fraction of CD16+, and of TCR-gamma/delta + T lymphocytes expressed the Ag. The analysis of TCR-alpha/beta + T cell clones showed that a small proportion (2 out of 20) weakly expressed Kp43 together with the CD8 and CD56 molecules. By immunoperoxidase staining of different tissues the anti-Kp43, reactivity was detected exclusively in lymphoid organs, where a minority of scattered cells was stained, and in some liver sinusoidal cells. Essentially all NK cells acquired Kp43 when stimulated with a B lymphoblastoid cell line. By contrast, the pattern of distribution of Kp43 remained stable upon in vitro culture of T-gamma/delta lymphocytes, thus delineating two subsets according to its expression. In lymphokine-activated killer populations, obtained by culturing either PBL or NK cells with high concentration of IL-2, most CD16+ and CD56+ cells became Kp43+. The Kp43-specific mAb inhibited the IL-2-dependent proliferative response of cultured NK and TCR-gamma/delta + T cells without affecting their non-MHC-restricted cytotoxicity. The partial inhibitory effect, which was mediated as well by pepsin digested F(ab')2 fragments, was lost upon reduction to Fab. The anti-Kp43 mAb did not interfere with the specific binding of IL-2 to its surface receptors. Altogether the data point out that the Kp43 dimer is involved in the regulation of the IL-2-dependent proliferative response of NK cells and a subset of TCR-gamma/delta + T lymphocytes.

Antibodies, Monoclonal↗
PubMed1990

[Obtaining monoclonal antibodies against outer membrane glycoproteins of Entamoeba histolytica].

The goal of this paper was the production of monoclonal antibodies capable of detecting relevant antigens from the surface of Entamoeba histolytica trophozoites, with the purpose of using them as a diagnostic test. The cellular fusion for obtaining the monoclonal antibodies (mAb) was done with spleen cells from BALB/c mice, previously immunized with glycoproteins from the membrane, as well as Sp2/0 cells. The hybridoma supernatants were tested with ELISA, using glycoproteins and lipopeptide phosphoglycans (LPPG) as antigens. Seven hybridomas producing mAb against the glycoproteins were found. Among these, three recognize LPPG. The ability of reacting with the mAb against two molecules disappeared for all the LPPG positive ones when were treated with meta-periodate, and only three reacted against the glycoproteins. All of the mAb were of the Ig M isotypes. They were characterized by Dot blot and Western blot assays. From the results, one may deduce that some mAb recognize as epitopes the polysaccharide portion, and thus infer that they are directed of against the surface and therefore, in the future, could be used with a diagnostic purpose.

Animals↗
PubMed1990

[Seroepidemiology of amebiasis in the northern region of the Republic of Mexico].

The object of paper has been the study of amebic seroepidemiology in the northern region of Mexico, by means of an immunoenzymatic assay in solid phase (ELISA). The proteic antigen was obtained from axenic culture of E. histolytica's trophozoites of strain HM1:IMSS, by means of solubilization with phenoxy polyethoxyethanol (Triton X-100). Standardization of the method was obtained by analysis of 80 sera from patients with both a clinical and radiologic diagnosis of amebic hepatic abscess and 80 sera from healthy patients. The sensitivity reached 95% and the specificity was 90.7%. 15,457 sera from eight Mexican northern states were tested as part of the National Seroepidemiologic Survey. A semiautomatic BIOMEK 1,000 (Beckman Ins.) equipment was used. The positive ratio varied between 2.0% in Southern Baja California and 4.92% in Chihuahua, with an average ratio for the whole group of 3.34%. The first three places, in descending order, are Chihuahua (4.92%), Sinaloa (4.01%) and Northern Baja California (3.78%). The positive man: woman ratio was 0.87:1 and fluctuated between 0.38:1 in Coahuila and 1.76:1 in Nuevo Leon. In the whole sample the positive ratio of men was 3.00% and in women was 3.43%. The antibody profile related to age, is similar to diseases reported to be highly endemic; the percentage of positive sera rose progressively up to the age of 20 years (4.05%), at which a plateau occurred with a slight descending tendency up to 60 years of age (3.54%), after which a clear descent in the positive index is seen. No important variations were observed when comparing groups of ages and sexes. The antibody level seems to show an inverse relationship with the incidence rate of amebiasis.

Adolescent↗
PubMed1990

Entamoeba histolytica inhibits the respiratory burst of polymorphonuclear leukocytes.

Since toxic oxygen metabolites generated during the respiratory burst of polymorphonuclear neutrophils (PMNs) constitute one of the most potent microbicidal mechanisms of PMNs, we evaluated the in vitro capacity of E histolytica to trigger the respiratory burst of human PMNs using a luminol-enhanced chemiluminescence assay a highly virulent strain of E. histolytica (HM1-IMSS) and a less virulent one (HK9-NIH) were incubated with PMNs at 4:1, 2:1 and 1:1 PMN:amoebae ratios. We have observed that the HM1-IMSS strain of E. histolytica do not induce PMN chemiluminescence as compared with zymosan (4.57.1.1 vs 106.5.11.3 mV/2 x 10(5) PMN, p less than 0.001). More importantly, the neutrophil oxidative response decreased progressively when the concentration of amoebae in the reaction mixture increased. When PMNs were challenged with zymosan in the presence of amoebae, the response was abrogated. These results suggest that E. histolytica inhibits the respiratory burst of PMNs. This represents a unique survival tactic and may contribute to the pathogenesis of amebiasis.

Animals↗
PubMed1989

[Quantification of mitral valve area: usefulness of Doppler].

We studied 34 patients with mitral stenosis by means of doppler echocardiography. Several patients had non significant associated valve lesions. The mitral valve area was measured by planimetry of the mitral orifice as recorded in the short axis view and also using the Hatle formula as applied to pulsed doppler recordings of transmitral flow velocity. The correlation between both measurements was excellent (r = 0.92). Direct measurements of mitral valve area obtained at the time of operation showed no significant differences from those estimated by echocardiography in 15 surgically treated patients.

Adolescent↗
PubMed1989

[Drug use among students in Cali, Colombia].

The use of alcohol, tobacco, marihuana, cocaine, and bazuco was examined in a cross-sectional study of a random sample of 512 secondary-school students enrolled in public and private schools in Cali, Colombia. The overall prevalence of use for any of these substances was 59.38% in the public schools and 36.96% in the private schools (z = 4.6, P less than 0.05). The probability of finding an alcohol user was about 55.26%. The frequency of use for all the substances was 18.9% in the public schools and 7.46% in the private ones. Experience with marihuana, cocaine, and bazuco was more frequent in the public schools. The average age of users (19.91 years) was higher than that of non-users (16.25 years): t = 8.34, P less than 0.05. Students in the public schools with a family history of mental illness had almost a ninefold greater risk of being substance users (RR = 8.84, IC 95% = 1.22-3.37); among students in the private schools, having personal conflicts with authority figures (teachers and the police) was a significant risk factor (RR = 2.03, IC 95% = 1.22-3.37).

Adolescent↗