Biomedical subjects
M Maldonado
Publications and source records attributed to M Maldonado.
State of emergency: HIV/AIDS among African Americans.
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Pathways to mental health services among inhabitants of a Mexican village.
The purpose of this article is to provide a description of the pathways to the utilization of mental health services among rural Mexicans in a village with a long-standing tradition of male labor migration to the United States. The authors developed a model of pathways to mental health service utilization on the basis of ethnographic field notes and in-depth interviews with 21 villagers who were "potential immigrants." The model describes five sequential help-seeking strategies that townspeople with mental health problems commonly follow to relieve the psychological and physical symptoms associated with their condition. The applications of the findings include the design of sensitive programs for the migratory population that not only incorporates but maximizes pre-existing culture-specific individual and community resources.
Inhibition of nitric oxide synthesis aggravates hepatic oxidative stress and enhances superoxide dismutase inactivation in rats subjected to tourniquet shock.
The role of nitric oxide (NO) on liver oxidative stress and tissue injury in rats subjected to tourniquet shock was investigated. This shock model differs from others in that injury is a consequence of remote organ damage. Liver oxidative stress becomes evident after hind limb reperfusion, as evidenced by the loss of total tissue thiols; by increases in tissue oxidized glutathione (GSSG), lipid peroxidation (LPO), plasma aminotransferases (alanine aminotransferase (ALT) and (aspartate aminotransferase (AST)), and plasma nitrites; and by a 36% loss in total superoxide dismutase (SOD) activity. Portal blood flow is reduced by 54.1% after 2 h of hind limb reperfusion. Inhibition of NO synthesis with Nomega-nitro-L-arginine methyl ester or L-arginine methyl ester increased mean arterial blood pressure; further reduced portal blood flow; and aggravated liver injury as assessed by further loss in total thiols, increased LPO and GSSG content, and further increases in plasma ALT and AST. Total plasma nitrites were lower than in control animals, and total tissue SOD activity decreased by more than 80%. Treatment with the NO donor sodium nitroprusside reverted the decrease in portal blood flow and also reverted tissue thiol loss, LPO, and GSSG increases, as well as the loss of ALT and AST to plasma and of SOD activity to levels comparable to untreated control shock animals. As expected, plasma nitrites were greater than in tourniquet control animals. These data support the hypothesis that endogenous NO formation protects the rat liver from the consequences of oxidative stress elicited by hind limb reperfusion in rats subjected to tourniquet shock.
Subcutaneous versus intravenous low-dose IL-2 therapy after autologous transplantation: results of a prospective, non-randomized study.
Use of IL-2 therapy after autologous transplantation is currently being explored to reduce relapse rate. Low doses of the cytokine induce significant immunomodulation avoiding the severe side-effects associated with high-dose IL-2 therapy. However, low-dose IL-2 is usually given by continuous infusion through central venous lines with the consequent risks of thrombosis and infections. Twenty-six consecutive patients who received autologous transplants received low-dose IL-2 after stable engraftment had been achieved. The first 13 patients (group A) were scheduled to receive 400,000/IU/m2/day for 3 months by continuous intravenous infusion. Ten of these patients suffered infectious episodes, mainly bacteriemias that often necessitated delaying IL-2 therapy (median delivered dose: 32% of planned). The next 13 patients were then assigned to receive IL-2 (800,000-1,000,000 IU/m2/day for 3 months) subcutaneously (group B). For group B patients, median dose intensity was 84% (P = 0.01 when compared with group A patients). Only one severe infectious episode was observed in these patients. Clinical toxicity in group B patients consisted mainly of s.c. nodules. Immunomodulation, measured as an increase in the absolute number of CD56+ cells and CD56+(bright) cells, was higher in patients who received the cytokine by the subcutaneous route (median peak increase of CD56+ cells: 160 and 220% for group A and B patients respectively; median peak increase of CD56+(bright) cells: 210% and 310% for group A and B respectively, P < 0.05 between groups A and B). No statistically significant increment of T lymphocytes was observed in any group. No hematologic toxicity was observed apart from eosinophilia, which was very marked in group B (P < 0.01). Our results show that low-dose s.c. IL-2 therapy is associated with low clinical and hematologic toxicity after autologous transplantation. The immunomodulation achieved is no less than that achieved with the i.v. approach.
Trends in HIV/AIDS among women of color.
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AIDS: risk behaviors among rural Mexican women married to migrant workers in the United States.
International migration between Mexico and the United States has been acknowledged as a phenomenon that may contribute to the spread of AIDS in rural Mexico. The purpose of this study is to identify the information held by the participants regarding AIDS and to describe selected high-risk behaviors for AIDS transmission among a representative sample of rural women living in Mexico who are married to immigrant temporary workers to the United States. The women who participated in the study were married, of reproductive age, and had active sex lives with their spouses. Results revealed that most of the women interviewed had at least some knowledge about AIDS. Although some misconceptions were evident, most of the information they had was accurate. About one-third of the women felt at risk for AIDS, mostly because they doubted their husbands' fidelity, or because in the last five years they had donated blood, received a blood transfusion, or received an intramuscular or intravenous injection. The results of the study are discussed within the sociocultural context that surrounds the lives of the women interviewed.
A follow-up report of a genome search for affective disorder predisposition loci in the Old Order Amish.
Progress of a full-genome scan for predisposition loci for affective disorder in the Old Order Amish is reported. LOD-score results have been previously published for 51 loci on chromosomes 1 and 11, collectively. The present report contains results for an additional 367 loci throughout the genome with extensive coverage on chromosomes 1, 2, 3, 4, 6, 7, 9, 10, 13, 14, 18, 19, and 21 (average marker density for these chromosomes = 10.7 cM). Analyses were conducted in a four-stage process: (1) two-point LOD scores were calculated for all loci under a dominant model with reduced penetrance, consistent with results of segregation analyses of these pedigrees; (2) a screen for the sharing of alleles in similarly affected individuals was used to highlight areas potentially important for further analysis; (3) the preceding areas and markers on densely covered chromosomes were analyzed using the affected-pedigree-member (APM) method; and (4) the sharing of extended haplotypes in affected individuals was examined in areas showing apparent clustering of significant allele sharing as assessed by the APM method. Of the 367 markers analyzed, no statistically significant LOD scores resulted. Some degree (P < .05) of allele sharing was found at 74 loci, and 3.8% of all markers analyzed (N = 14) passed more stringent significance criteria suggestive of linkage (P < or = .001 for at least one of the weighting functions). Multilocus APM and detailed exploration of extended haplotype sharing in areas highlighted by the APM analyses provided methods for more informative exploration of potentially suggestive results but did not identify areas clearly involved in the etiology of affective disorder in this population.
The prevention of coronary heart disease in women.
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Ibuprofen protects rat livers from oxygen-derived free radical-mediated injury after tourniquet shock.
Rats subjected to tourniquet shock suffer a severe form of circulatory shock, tissue and organ oxidative stress, and final multiple system organ failure (MSOF) and death of the animals within 24 h of tourniquet release. The oxidative damage observed in hind-limb muscle tissue after reperfusion does not by itself account for the final systemic and lethal MSOF. We have postulated that organ failure has its genesis in a primary perfusion abnormality, e.g. the hind limbs, which is followed by secondary hypoperfusion of other organs, such as the liver, as has been shown to be the case in several septic shock models. It has also been shown that injured or necrotic tissue can activate neutrophils, Küpffer cells, platelets, and both the complement and coagulation cascades. In turn, complement activation also leads to neutrophil and Küpffer cell activation as assessed by their capacity to generate oxyradicals. Herein we have evaluated the potential protective effect of ibuprofen on hepatic oxygen-derived free radical production, as well as its effects on both polymorphonuclear leucocyte (PMN) activation and liver infiltration. The protective effect of ibuprofen on hepatic oxidative injury was assessed by determining total thiol groups (SH), thiobarbituric acid-reactive substances (TBARS), and by the release of aspartic acid (AsT) and alanine (AIT) aminotransferases in control animals, in animals subjected to 5 h of tourniquets, and in animals after 2 h of hind-limb reperfusion. Liver infiltration by PMNs was determined by histology after staining with eosin-hematoxylin, and PMN activation by their capacity to reduce nitro blue tetrazolium (NBT).(ABSTRACT TRUNCATED AT 250 WORDS)
Treatment of psychotic disorders in the United States and France: three comparisons.
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Characterization of Paraguayan Trypanosoma cruzi strains isolated from acute patients of Chagas disease.
Five Paraguayan Trypanosoma cruzi strains, isolated from acute chagasic patients, were studied by their behavior in BALB/c mice, metacyelogenesis, bio-metry of metacyclic forms and lectin agglutination. Early and intermediate parasitemic peaks were observed and the strains did not show high virulence. Metacyclogenesis capacity was not higher than 50% in all cases and there were no considerable differences in the biometry. They all belong to WGA-type strains according to the lectin agglutination assays except for one strain that agglutinated with WGA and PNA lectins. Although previous schizodeme analysis of these strains showed rather homogeneous profiles, biological features were quite heterogeneous.
Cardiovascular toxicities related to the infusion of cryopreserved grafts: results of a controlled study.
To evaluate cardiovascular toxicities associated with the infusion of cryopreserved grafts, we prospectively monitored the infusions of 29 autologous bone marrow transplant (BMT) recipients. Fifteen allogeneic BMT recipients served as a control group. Cardiac rhythm was recorded continuously with the Holter technique from at least 2 h before the start of graft infusion until 24 h after completion. Blood pressure was closely monitored during the same period. Graft infusions were performed through a standard transfusion filter with breaks between aliquots. When the infusion had commenced, diuretics were given frequently (40 and 40% of allogeneic BMT and autologous BMT recipients, respectively) to avoid fluid overload. Non-cardiovascular clinical toxicities were observed more frequently in autologous BMT patients (41% vs 6%, p = 0.02) and no significant differences were seen between autograft and allograft recipients in any of the measured cardiovascular parameters. The heart rate decreased slightly in both groups but no patient in either group had a heart rate of < 60 b.p.m. or heart block. No significant changes in blood pressure were detected in either group. Ventricular ectopic beats/atrial ectopic beats ratio increased in the autologous BMT group after graft infusion (0.7 vs 0, p = 0.1). Time to engraftment did not differ significantly from other published series. Our results suggest that increasing infusion time of cryopreserved material and using a standard filter may reduce toxicities associated with the infusion of cryopreserved grafts. Early administration of diuretics may contribute to better control of blood pressure.
Mechanisms of the toxic effect of lead. I. Free lead in erythrocyte.
In this work, a selection of children was examined based on their free erythrocyte protoporphyrin (FEP) and total blood lead (PbB) contents. Two groups with clear differences in lead sensibility were selected. One group with high FEP levels (deep lead alteration), named "normal," and one group with low FEP levels (discrete lead alteration), named "lead tolerant," and both with similar PbB concentration, were formed. The selection, based on FEP level, showed a correlation with other indicators (neuromotor alterations). A lower activity of the enzymes Glyceraldehyde 3-phosphate dehydrogenase (GA3PD), Glucose 6-phosphate dehydrogenase (G6PD), 6-phosphogluconate dehydrogenase (6PGD), and Lactate dehydrogenase (LDH) was found in the normal group when compared to the tolerant group. Therefore, the influence of the lead acetate upon the same erythrocyte enzyme activities was investigated. Lead inhibition of the enzymes GA3PD and G6PD was found, and this inhibition could be related to the free lead content found in the erythrocytes. Inhibition of the enzymes 6PGD and LDH was also found, but these enzymes were not inhibited by exposure to lead acetate. Erythrocyte free lead content was high in the normal group when compared to the lead tolerant group and could be a determinant factor in the biochemical alterations found. Low erythrocyte free lead contents could be an indicator of lead tolerance. TCA-precipitation was found to be a useful method to evaluate free lead content; it gave similar results to gel filtration molecular chromathography.
Characterization of Trypanosoma cruzi isolates from Paraguay, using restriction enzyme analysis of kinetoplast DNA.
Eleven Paraguayan strains of Trypanosoma cruzi, from Chagas' disease patients and the bug vectors, were examined by restriction endonuclease analysis of kinetoplast DNA using Hae III, Msp I, Eco RI, HinfI, Taq I and Rsa I. Four schizodeme-profile groups were identified. Group 1 had much simpler profiles than groups 2, 3 and 4 and, although there were homogeneous profiles in the latter three groups, each group could be distinguished from the others. The profiles of group 1 could not be matched with any of the standard strains from Brazil, Chile and Columbia included in the schizodeme comparison. The profiles of groups 3 and 4 shared most features with those standards of the Brazilian Z2 zymodeme.
Oxygen-derived free radicals mediate liver damage in rats subjected to tourniquet shock.
The placement of rubber band tourniquets upon rat hind-limbs for 5 h followed by reperfusion of the extremities results in a severe form of circulatory shock characterized by hypotension and death within 24 h of tourniquet release. Oxidative damage to muscle tissue is an early consequence of hind-limb reperfusion on tourniquet release, yet this local damage does not explain the lethal hypotensive shock state which evolves within the next 24 h. Multiple system organ failure (MSOF), of as of yet unknown causes, is usually described in relation to several shock states. It has been suggested that injured or necrotic tissue may activate neutrophils, platelets, and the coagulation system leading to embolization in remote tissues. Effective decreases in hepatic blood flow have been observed in several forms of sepsis which precedes the biochemical evidence consistent with an ischemic insult of the liver. In support of our original hypothesis, that organ failure has its genesis in a primary perfusion abnormality with secondary ischemic organ injury, herein we have assessed the possibility that oxygen-derived free radicals are generated in the liver of rats after reperfusion of their hind-limbs on release of the tourniquets. We report on the protective effects of allopurinol (ALLO) and a mixture of superoxide dismutase (SOD) catalase (CAT) and dimethylsulfoxide (DMSO) on liver free sulfhydryl content (SH), thiobarbituric acid-reactive substances (TBARS), and on the release of aspartic acid (AsT) and alanine aminotransferase (AlT) activities, and of alkaline phosphatase during a 5 h tourniquet period and after 2 h of reperfusion of the hind-limbs. During the hind-limb ischemic period hepatis tissue SH levels remained essentially constant during the first hour (6.02 +/- 0.36 to 5.65 +/- 0.20 mumoles/g wet tissue), and decreased significantly, over and above the normal circadian decrease of liver glutathione levels, to 4.02 +/- 0.69 mumoles/g wet tissue after the third hour and remained lowered until tourniquet release. A further significant decrease (3.11 +/- 0.49 mumoles/g wet tissue) was observed after 2h of reperfusion. TBARS production remained constant during the 5 h hind-limb ischemic period (168.4 +/- 37.3 mumoles/g wet tissue) and rose by 55% to 261.7 +/- 55.8 mumoles/g wet tissue after 2 h of tourniquet release. ALLO, but not the SOD-CAT-DMSO combination, protected hepatic SH loss during the hind-limb ischemic insult, yet both offered protection after 2 h of tourniquet release.(ABSTRACT TRUNCATED AT 400 WORDS)
Autologous bone marrow transplantation after in vitro purging with monoclonal antibodies and complement in acute lymphoblastic leukemia.
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