Biomedical subjects

E Alvarez

Publications and source records attributed to E Alvarez.

At least 109 records · Page 6Linked to original sources

PubMed1999

Increased glucagon-like peptide-1 receptor expression in glia after mechanical lesion of the rat brain.

Glucagon-like peptide-1 (GLP-1)(7-36) amide, a member of the glucagon and related peptides family, and its receptor have an anatomically specific expression in the brain. Furthermore, the GLP-1 receptor is expressed in both neurons and glia. Because after a penetrating injury a large population of astrocytes become activated and augment their expression of numerous substances, we have used in situ hybridization to determine whether the expression of the GLP-1 receptor increases in response to a penetrating injury. We have found that GLP-1 receptor expression increases dramatically along the border of the injury. Furthermore, this expression can be colocalized to glial fibrillary acidic protein (GFAP) and non-GFAP mRNA containing cells, suggesting that at least part of this increase is due to an increase in GLP-1 receptor expression in glial cells.

Animals↗

PubMed1999

Severe short-bowel syndrome in children. Clinical experience.

INTRODUCTION: Innovative surgical and pharmacological therapeutic measures in short-bowel syndrome (SBS) are constantly changing the prognosis of this devastating condition. The aim of this paper is to present our most recent experience in the treatment of this disease, with particular emphasis on the impact of home parenteral nutrition (HPN) and the use of growth hormone (GH). METHODS: A group of 8 patients with severe SBS have been studied for the past 4 years. Intestinal length of less than 25% normal at the time of bowel resection was the criterion for inclusion in this study. RESULTS: Mean age at the time of diagnosis was 2 years (ranging from 1 day to 9 years). The etiology of the SBS was Hirschsprung's disease (n = 3), midgut volvulus (n = 2), gastroschisis (n = 1), omphalocele with ileal atresia and necrotizing enterocolitis (n = 1) and Crohn's disease (n = 1). Length of the residual bowel was 8 and 50 cm with ileocecal valve (ICV) preservation and 23, 27, 30, 50, 70, 100 cm without ICV. Sixty percent of the patients survived. Two patients died due to fulminant gram-negative sepsis and one due to cardiac malformation. Two patients are still on parenteral nutrition (PN) providing 30 and 60% of total calories. Human GH (0.3 U/kg/day) was used in two patients over a period of 28 days. In these patients, an increased tolerance to enteral feeding was observed. HPN was provided in 5 cases, allowing regular school attendance in 3 patients. In 3 cases, discontinuation of the PN was achieved at 24, 25 and 35 months respectively. CONCLUSIONS: Human GH can improve tolerance of enteral feeding. HPN has a beneficial effect on child behaviour. Intestinal transplantation must be considered when no other surgical or medical measures are available.

Child↗

PubMed1999

Survey of Bartonella species infecting intradomicillary animals in the Huayllacallán Valley, Ancash, Peru, a region endemic for human bartonellosis.

The natural cycle of Bartonella bacilliformis remains uncertain, and the suspected existence of animal reservoirs for the bacterium has never been convincingly demonstrated. We conducted a survey of Bartonella species infecting intradomicillary animals in a bartonellosis-endemic region of Peru, obtaining blood from 50 animals living in the homes of 11 families whose children had recently had bartonellosis. Bartonella-like bacteria were recovered from four of nine small rodents included in the study, but from none of the 41 domesticated animals. Identification and comparison of these isolates, and two Bartonella-like isolates obtained from Phyllotis mice in a different endemic region of Peru using serologic and genotypic methods indicated that although none were strains of B. bacilliformis, five were probably representatives of three previously unrecognized Bartonella species and one was a likely strain of the pathogenic species B. elizabethae.

Animals↗

PubMed1999

MTA (LY231514) in combination treatment regimens using human tumor xenografts and the EMT-6 murine mammary carcinoma.

An important component in the development of a new anticancer drug is an understanding of its potential for inclusion in combination treatment regimens. LY231514, a multitargeted antifolate (MTA), was tested in combination with cisplatin, methotrexate, 5-fluorouracil, paclitaxel, docetaxel, doxorubicin, LY329201 (a glycinamide ribonucleotide formyltransferase [GARFT] inhibitor), and fractionated radiation therapy in vivo using EMT-6 mammary carcinoma, human HCT 116 colon carcinoma, and human H460 nonsmall cell lung carcinoma grown as xenografts in nude mice. Isobologram methodology was used to determine the additivity or synergy of the combination regimens. MTA administered with cisplatin, paclitaxel, docetaxel, or fractionated radiation therapy produced additive to greater than additive tumor response by tumor cell survival assay and tumor growth delay. While an additive tumor response was observed when MTA was administered with methotrexate, synergistic tumor responses were seen when MTA was administered with the GARFT inhibitor, LY329201, or with the topoisomerase I inhibitor, irinotecan. MTA was administered in combination with full doses of each anticancer agent studied, with no evidence of increased toxicity resulting from the combination.

Animals↗

PubMed1999

[Diagnostic value of transjugular liver biopsy in liver transplant recipients].

Liver biopsy after hepatic transplantation essential for the correct diagnosis of grant dysfunction. However, seriously imparied coagulation or massive ascites contraindicate percutaneous liver biopsy. In these cases transjugular liver biopsy may be valid alternative. in this study the efficacy, feasibility and safety of 69 transjugular biopsies carried out in 56 liver transplant recipients are evaluated. The suprahepatic veins were catheterized in 100% of the patients and histological samples were obtained in 63 (91.3%). The number of portal tracts was greater than six in 20.6% of the samples, lower than three in 35% and oscillated between four and six in 44%. The specimens obtained were sufficient for diagnosis in 82.5% of the patients, the overall diagnostic efficacy being 75.4%. The most common histological diagnosis (28.8%) was graft damage, while rejection represented 7.7%. Only one patient (1.18%) suffered a serious complication after transjugular biopsy. Transjugular biopsy is feasible and effective in liver transplant recipients with severely imparied coagulation.

Biopsy, Needle↗

PubMed1998

Glucagon-like peptide-1 (7-36) amide as a novel neuropeptide.

Although earlier studies indicated that GLP-1 (7-36) amide was an intestinal peptide with a potent effect on glucose-dependent insulin secretion, later on it was found that several biological effects of this peptide occur in the brain, rather than in peripheral tissues. Thus, proglucagon is expressed in pancreas, intestine, and brain, but post translational processing of the precursor yields different products in these organs, glucagon-like peptide-1 (7-36) amide being one of the forms produced in the brain. Also, GLP-1 receptor cDNA from human and rat brains has been cloned and sequenced, and the deduced amino acid sequences are the same as those found in pancreatic islets. Through these receptors, GLP-1 (7-36) amide from gut or brain sources induces its effects on the release of neurotransmitters from selective brain nuclei, the inhibition of gastric secretion and motility, the regulation of food and drink intake, thermoregulation, and arterial blood pressure. Central administration (icv) of GLP-1 (7-36) amide produces a marked reduction in food and water intake, and the colocalization of the GLP-1 receptor, GLUT-2, and glucokinase mRNAs in hypothalamic neurons involved in glucose sensing suggests that these cells may be involved in the transduction of signals needed to produce a state of fullness. In addition, GLP-1 (7-36) amide inhibits gastric acid secretion and gastric emptying, but these effects are not found in vagotomized subjects, suggesting a centrally mediated effect. Similar results have been found with the action of this peptide on arterial blood pressure and heart rate in rats. Synthesis of GLP-1 (7-36) amide and its own receptors in the brain together with its abovementioned central physiological effects imply that this peptide may be considered a neuropeptide. Also, the presence of GLP-1 (7-36) amide in the synaptosome fraction and its calcium-dependent release by potassium stimulation, suggest that the peptide may act as a neurotransmitter although further electrophysiological and ultrastructural studies are needed to confirm this possibility.

Animals↗

PubMed1998

Infection control strategies in a neonatal intensive care unit in Argentina.

An intervention strategy was designed to reduce the high endemic rates of nosocomial bacteraemia in a neonatal intensive care unit (NICU) in Argentina where no changes can be expected in the ratio of patients to nurses. After surveillance of high-risk procedures, guidelines were developed by physician and nurse consensus, based on CDC guidelines and adapted to actual circumstances for handwashing, handling of infants, care of intravenous lines and suction of endotracheal tubes. These guidelines were taught to all involved personnel and made effective on July 1, 1995. Data from blood cultures obtained after 72 h of life and on patient-days in the unit were collected for 1 year periods before (P1), and, after (P2) this intervention strategy was instituted. During P1, the overall bacteraemia rate was 20/1000 patient-days, and the Gram-negative bacteraemia rate was 7.7/1000 patient-days but bacteraemia and Gram-negative bacteraemia rates dropped to 12.4 and 2.2/1000 patient-days respectively (P < 0.003) during P2. We conclude that simple intervention strategies such as the one developed at our institution can reduce rates of nosocomial infection.

Argentina↗

PubMed1998

Chemistry of soil solutions under different kinds of vegetation in the vicinity of a thermal power station.

The influence of atmospheric deposition on the chemical characteristics of soil solutions in a small catchment area in NW Spain was studied. The soils, developed from slates, were sampled from seven sites supporting different forms of vegetation (deciduous and pine forest and heath). Soil solutions were extracted, by the column displacement method, from soil samples collected monthly from March 1992 until November 1993. The solutions were acidic with a low content of basic cations. The most common ions in all horizons were Cl(-) and Na(+), due to marine influence. In the surface horizons (0-10 cm), relatively high concentrations of SO(2-)4 (150-380 micromol litre(-1)) and Zn (approximately 2 micromol litre(-1)) were obtained, with good correlation between the two ions. These results, along with the prevalence of inorganic forms of Al (50-90% of total Al), were related to the effects of acidic deposition in the catchment area. The more rapid breakdown of litter in the soils under deciduous forest explains the greater ionic concentrations obtained in these solutions.

Journal Article↗

PubMed1998

Tianeptine therapy for depression in the elderly.

1. Depression is frequent in the elderly but difficult both to diagnose and treat due to a number of distinctive features. 2. Tianeptine is a novel antidepressant with a reverse mode of action to that of the selective serotonin reuptake inhibitors yet with proven efficacy and safety. 3. 63 elderly patients (mean age:68.8 years; range:65-80 years) with depressive symptoms (major depression:55.6%; dysthymia:44.4%) were included in a 3-month open multicenter study with tianeptine (25 mg daily). 4. 43 patients (68.2%) completed the study. There were no drop-outs due to side-effects. Total Montgomery and Asberg Depression Rating Scale scores were significantly decreased (p < 0.01) on day 14, with a response rate of 76.7%. 5. Improvements were also observed in anxiety and cognitive performance. Side-effects were seen in only 11.7% of patients, with no changes in laboratory or ancillary safety parameters. Tianeptine is thus effective and well tolerated in this category of patient.

Aged↗

PubMed1998

Study of an Argentine mistletoe, the hemiparasite Ligaria cuneifolia (R. et P.) Tiegh. (Loranthaceae).

Ligaria cuneifolia (R. et P.) Tiegh. is an hemiparasite species used in Argentine folk medicine as a substitute for the European mistletoe (Viscum album L.) based on its putative activity of decreasing high blood pressure. This paper analyzes flavonoid composition, protein constituents and the possible immunomodulatory and antitumoral effects of this species. Micromolecular study disclosed quercetin-free, quercetin-glycosylated and proanthocyanidins corresponding to cyanidin monomers, which implies a particular metabolic pathway. Proteins present in L. cuneifolia extracts analyzed by SDS-PAGE presented multiple bands with molecular weights ranging from 14 to 90 kD. These features contribute to the characterization of the native mistletoe. As V. album is being used in cancer treatment due to its immunomodulatory and antitumoral activity, the action of aqueous L. cuneifolia extracts on murine lymphocytes was investigated. Culture of murine spleen cells alone or stimulated with Concanavalin A or lipopolysaccharide in presence of L. cuneifolia extracts indicated a certain stimulation of splenocytes alone and an inhibition of splenocytes stimulated with Concanvalin A or lipopolysaccharide. An inhibitory effect was also observed on the proliferation of murine leukemia cells. In addition, aqueous extracts increased nitric oxide production by murine macrophages. These results suggest that L. cuneifolia extracts exert an immunomodulatory effect on the mouse immune system.

Animals↗

PubMed1998

Reliability of reporting self-measured blood pressure values by hypertensive patients.

For self-measurement of blood pressure to be useful, patient reporting of test results must be reliable and accurate. Until now no study directly measured the accuracy and reliability of patients' reporting of self-measured blood pressure values. Thirty hypertensive patients (69 +/- 11 years) were instructed to measure blood pressure at home over 14 days with the highly accurate Omron IC monitor and to keep a record of all readings in a patient logbook. To assess the reliability of the records, patients were not informed about the memory capacity of the device. We compared automatically stored blood pressure readings with the respective logbook entries to analyze deletion (under-reporting), addition (over-reporting), and precision of reporting of test results. The prevalent pattern was under-reporting, averaging 36% +/- 24% (3% to 89%), which occurred significantly more than over-reporting (9% +/- 11%; 0% to 38%). The precision of reporting (identical values at corresponding times) was 76% +/- 34% (0% to 100%). This observer error did not affect group comparisons of automatically stored values and logbook entries, although the estimated limits of agreement were wide. Blood pressure control, duration of hypertension, age, or previous use of self-measurement and patterns of logbook entries were not found to be predictive of the patients' reliability. Our results demonstrate a substantial observer error in the reporting of self-measured blood pressure values. This bias may be reduced by memory-equipped blood pressure devices.

Blood Pressure Determination↗

PubMed1998

Relationship between blood serotonergic variables, melancholic traits, and response to antidepressant treatments.

The relationship between peripheral serotonergic variables, melancholic traits, and clinical improvement after antidepressant treatment was examined in 83 drug-free major depressive patients. Plasma serotonin (5-HT) concentrations was lower in untreated melancholic patients (1.00 +/- 0.11 vs. 1.84 +/- 0.28 ng/mL, p < 0.008; N = 40 and 43, respectively). A tendency was observed for plasma 5-hydroxyindoleacetic acid (p < 0.06), whereas platelet 5-HT and plasma tryptophan did not differ between groups. After blood sampling and clinical ratings, treatment began with fixed doses of 5-HT uptake inhibitors (clomipramine or fluvoxamine), monoamine oxidase inhibitors, or tianeptine, a 5-HT uptake enhancer. There was no significant difference in response rates between patients with and without melancholic traits. The relationship between the clinical response at 6 weeks (>50% reduction of baseline Hamilton score) and the pretreatment values of biochemical variables was examined. Responders had a lower pretreatment platelet 5-HT (530 +/- 36 vs. 664 +/- 50 ng/10(9) platelets, p < 0.03; N = 44 and 39, respectively). Patients with a platelet 5-HT concentration above 800 ng/10(9) platelets had a lower response rate than those below this value (p < 0.003). This difference was maximal in the subgroup of patients treated with 5-HT uptake inhibitors (N = 49). In this subgroup, the response rates of patients with 5-HT concentrations below and above the cutoff point were, respectively, 70% and 17% (p < 0.001). A pretreatment platelet 5-HT value above 800 ng/10(9) platelets had a predictive value for a negative response of 92%. These results suggest the presence of biochemical differences in the peripheral serotonergic system between melancholic and nonmelancholic patients. The inverse relationship between the pretreatment platelet 5-HT content and clinical response may be useful in the investigation of the relationship between the 5-HT system and antidepressant response.

Adult↗

PubMed1998

The incidence of breastfeeding in our environment.

AIMS: To establish the incidence of breastfeeding and its persistence after three and six months; to identify the factors which might modify attitudes towards breastfeeding. METHODS: An interview, administered to mothers of term born infants of adequate weight for gestational age, after a delivery of one sole foetus, between 1st March and 31st May 1997. Mothers were asked about: previous pregnancies, children and type of feeding; during this pregnancy, their intentions regarding feeding; supervision of pregnancy, and the information received regarding breastfeeding; their work situation, and educational level. Questions regarding the neonatal period referred to the kind of lactation initiated, information received, and the use of a pacifier and supplements. A two-part poll was conducted by telephone after 3 months and after 6 months, enquiring about what kind of feeding was used, the reason for change (if any), who had provided information regarding the change, degree of satisfaction, and work situation. Three hundred and twenty-nine polls were completed, accounting for 70% of the births. RESULTS: During pregnancy, 91% of mothers had intended to breastfeed, and this figure was maintained at birth. A trend towards breastfeeding was observed: 74% of those who had fed earlier children artificially started breastfeeding this time, compared with 7% of mothers who changed from breastfeeding to artificial feeding. After three months, 57% of mothers continued to breastfeed their child, and 24% after six months. High educational level exerted a positive influence on the duration of breastfeeding (OR = 1.7; p = 0.03) and the giving of supplements had a negative effect (OR = 0.4; p = 0.04). The fact that mothers work outside the home did not modify the duration of breastfeeding. CONCLUSIONS: The rate of breastfeeding is high (91%). Among mothers with previous children, there is a greater trend to change from artificial feeding to breastfeeding (74% vs 7%; p < 0.002). The mother's educational level is the most important positive factor, and the early giving of supplements the most important negative factor.

Attitude↗

PubMed1998

The Onchocerciasis Elimination Program for the Americas: a history of partnership.

The decision in 1987 by the pharmaceutical firm Merck & Co. to provide Mectizan (ivermectin) free of charge to river blindness control programs has challenged the international public health community to find effective ways to distribute the drug to rural populations most affected by onchocerciasis. In the Americas, PAHO responded to that challenge by calling for the elimination of all morbidity from onchocerciasis from the Region by the year 2007 through mass distribution of ivermectin. Since 1991, a multinational, multiagency partnership (consisting of PAHO, the endemic countries, nongovernmental development organizations, the Centers for Disease Control and Prevention in Atlanta, Georgia, as well as academic institutions and funding agencies) has developed the political, financial, and technical support needed to move toward the realization of that goal. This partnership is embodied in the Onchocerciasis Elimination Program for the Americas (OEPA), which is supported by the River Blindness Foundation (RBF) and now by the Carter Center. OEPA was conceived as a means of maintaining a regional initiative to eliminate what is otherwise a low priority disease. Since its inception in 1993, the OEPA has provided more than US$ 2 million in financial, managerial, and technical assistance to stimulate and/or support programs in Brazil, Colombia, Ecuador, Guatemala, Mexico, and Venezuela, so as to take full advantage of the Merck donation. Now halfway into a five-year, US$ 4 million grant provided through the Inter-American Development Bank, the OEPA's capacity to support the regional initiative is assured through 1999.

Americas↗

PubMed1998

Correlation of sperm motility with mitochondrial enzymatic activities.

Until now, little attention has been paid to the contribution of mitochondrial dysfunction to germinal tissue disorders. The target of this study was to investigate the relationship between sperm motility and mitochondrial respiratory chain enzyme activities. The results obtained showed that semen samples of control individuals (n = 33) have substantially higher activities of complexes I, II, and IV compared with those of asthenozoospermic subjects (n = 86). Moreover, a direct and positive correlation was found in the whole population studied between spermatozoa motility and all the mitochondrial respiratory complex activities assayed (I, II, I+III, II+III, and IV). The ratio of these enzymes to citrate synthase (a reliable enzymatic marker of mitochondrial volume) activities did not correlate with sperm motility. This suggests that motility depends largely on the mitochondrial volume within the sperm midpiece. These observations could be of physiopathological relevance because they suggest that factors affecting the mitochondrial energy production could be then responsible for particular cases of idiopathic asthenozoospermia.

Citrate (si)-Synthase↗

PubMed1998

[Standardization of the lethal dose 50% of Leptospira interrogans strains used in the control of the leptospirosis cuban vaccine for human use].

The LD50 of strains of L. interrogans used in the potency assay of the Cuban trivalent leptospiral vaccine intended for human use was standardized. The control of the leptospires content of the cultures by means of the adjusting dilution (10 to 12 leptospires per field) was introduced. That was the key of the standardization of the assay, since it guaranteed the reproducibility of the estimate of the LD50 value for each serogroup: 10(5.98) for canicola, 10(5.60) for icterohaemorrhagiae and 10(6.60) for pomona, with the following limits for an interval of 1 log10: 10(4.98)-10(6.98), 10(4.60)-10(6.60) and 10(5.49)-10(7.49), respectively; whereas for a 95% (+/- 2 SD) confidence interval the values were: 10(5.54)-10(6.19); 10(5.33)-10(5.75) and 10(6.35)-10(6.60), respectively. These values were lower than the previous ones, which means ever more reproducibility. The methodology described proved to be satisfactory for the standardization of the LD50 of the challenge strains and it could also be used for evaluating the virulence of other strains of L. interrogans, including those used for the vaccine production.

Cuba↗

PubMed1997

Randomised, double-blind, placebo-controlled trial of pindolol in combination with fluoxetine antidepressant treatment.

BACKGROUND: Major depression affects more than 5% of the population and is a serious health and economic problem. Antidepressants have a slow onset of action and are effective in less than two-thirds of patients. The biochemical effects of selective serotonin reuptake inhibitors may be limited by the negative feedback from serotonin autoreceptors. Pindolol is an antagonist of both serotonin autoreceptors and beta-adrenoceptors. We studied the effect of the addition of pindolol to fluoxetine antidepressant treatment. METHODS: Of 132 eligible patients with major depression, 111 were randomly assigned to treatment with fluoxetine (20 mg daily) and either placebo or pindolol (7.5 mg daily). Patients were assessed twice a week for the first 3 weeks of active treatment and then once a week until the end of the study (42 days). Hamilton and Montgomery-Asberg depression-rating scales were used to assess depression severity. FINDINGS: The proportion of patients who responded to treatment with fluoxetine and pindolol was greater than that with fluoxetine and placebo (41/55 [75%] vs 33/56 [59%], [90% CI 1.1-30.1], p = 0.04). The proportion of patients who achieved a sustained response was also greater in the fluoxetine and pindolol group than in the fluoxetine and placebo group (38/55 [69%] vs 27/56 [48%] [5.9-35.9], p = 0.03). The number of days to reach a sustained response was lower in the fluoxetine and pindolol group than in the fluoxetine and placebo group (median 19 vs 29 days, p = 0.01), however, there was no difference in the time-to-onset of clinical improvement when stringent conditions were used (15 vs 18 days, p = 0.20). INTERPRETATION: The addition of pindolol to fluoxetine antidepressant treatment increases the effectiveness of fluoxetine therapy. Further work is needed to resolve whether the time to clinical improvement benefits from this combination and whether the increase in efficacy occurs with other antidepressants.

Adult↗

PubMed1997

Immunohistochemical evidence of immunopathogenetic mechanisms in chronic hepatitis C recurrence after liver transplantation.

Viremia and genotype are implicated in a rapid course of posttransplant hepatitis C virus (HCV) infection recurrence, but the role played by host immune reactions has not yet been evaluated. We correlated the degree of liver injury with the intrahepatic expression of molecules involved in immune response. The study included 32 biopsies of 30 liver transplant recipients. Recurrence of viremia was detected by Amplicor assay. Genotype was tested by Inno-Lipa. Cryostat sections were assessed by immunohistochemistry, using a wide panel of monoclonal antibodies. Correlations between histological-immunohistochemical semiquantitative evaluation and levels of viremia were performed. In severe hepatic inflammation, high numbers of activated cytotoxic T cells were found, along with marked hepatocellular expression of beta 2-microglobulin (beta 2-MG) and intercellular adhesion molecules. Likewise, a strong vascular adhesion molecule expression was observed mainly in those areas that were more inflamed. A striking endoglin reactivity was detected in enlarged portal tracts, and the presence of neoformed microvessels was also noteworthy. By contrast, in mild hepatic inflammation only a few activated T cells were detected, together with a weaker reactivity for all molecules studied. The level of viremia did not correlate with the degree of liver damage. The severe forms of post-transplant HCV infection recurrence are associated with a marked and aberrant intrahepatic expression of molecules involved in antigen recognition, and intercellular and vascular adhesion, decisive in regulating the recruitment and activation of cytotoxic T lymphocytes.

Adult↗