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Biomedical subjects

J Díaz

Publications and source records attributed to J Díaz.

At least 55 records · Page 3Linked to original sources
PubMed2000

Depletion of liver glutathione potentiates the oxidative stress and decreases nitric oxide synthesis in a rat endotoxin shock model.

OBJECTIVE: To verify the effects of liver glutathione depletion on redox status and nitric oxide system in a rat endotoxic shock model. DESIGN: Prospective, randomized, controlled study on rats. SETTING: A cardiocirculatory research laboratory. SUBJECTS: A total of 28 Sprague-Dawley male rats (200-250 g body weight) were divided into four experimental groups. INTERVENTIONS: Arterial blood, liver, and lung samples were taken from each animal under sodium pentobarbital (40 mg/kg i.p.) anesthesia 4 hrs after lipopolysaccharide (LPS group: 5 mg/kg i.p.; n = 7) or vehicle (control group: isotonic NaCl sterile solution i.p.; n = 7) treatments. Phorone (250 mg/kg i.p.) was injected to deplete glutathione in another two experimental groups of rats 30 mins before LPS (phorone+LPS group; n = 7) or vehicle (phorone group; n = 7) treatments, and 4 hrs later the same samples as in LPS and control groups were taken under anesthesia. MEASUREMENTS AND MAIN RESULTS: Compared with the control group, the LPS group presented higher plasma concentration of end products of nitric oxide metabolism nitrites/nitrates, higher lung activity of inducible nitric oxide synthase, and oxidative stress defined by increased plasma concentration of the lipid peroxides malonaldehyde and 4-hydroxynonenal, and decreased plasma total antioxidant capacity. Treatment with phorone depleted liver glutathione (80% to 90%). In the liver glutathione-depleted animals, the oxidative stress induced by LPS was potentiated and blunted the increases in inducible nitric oxide synthase and plasma nitrites/nitrates. CONCLUSION: These results show that depletion of the liver glutathione increases the oxidative stress and decreases nitric oxide synthesis of LPS-induced shock in rats.

Animals↗
PubMed2000

17beta-estradiol prevents oxidative stress and decreases blood pressure in ovariectomized rats.

In this study, we tested whether estrogen deficiency is associated with oxidative stress and decreased nitric oxide (NO) production, which could be responsible for an increased blood pressure in ovariectomized rats. Hemodynamic studies were performed on conscious, chronically instrumented rats. Chronic estrogen replacement on ovariectomized rats lowered blood pressure approximately 13 mmHg, from 119 +/- 3 mmHg in ovariectomized rats to 106 +/- 3 mmHg in ovariectomized-treated rats; it was also accompanied by an increase in cardiac index and vascular conductance, achieving hemodynamic values similar to those shown by sham-operated rats. N(G)-nitro-L-arginine methyl ester administration lowered significantly less the vascular conductance (0.14 +/- 0.01 vs. 0.22 +/- 0.03 and 0.26 +/- 0.01 ml. min(-1). mmHg(-1)/100 g; P < 0.05) in ovariectomized rats than in the sham-operated and estrogen-treated ovariectomized rats, respectively. Estrogen replacement prevented the lower plasma levels of nitrites/nitrates observed in ovariectomized rats. The lower plasma total antioxidant status and reduced thiol groups and the increase in plasma lipoperoxides presented in ovariectomized animals were reestablished with the estrogen treatment. These results show that estrogen administration decreases blood pressure and increases vascular conductance in ovariectomized rats. This effect may be related to an increase in NO synthesis and/or preventing oxidative stress, then improving endothelial function.

Animals↗
PubMed2000

[Relationship between leptin and insulin blood levels in obese and lean Chilean women].

BACKGROUND: Leptin, a product of ob gene and insulin blood levels, are proportional to the amount of adipose tissue. Insulin could have an independent regulatory effect on leptin secretion. AIM: To assess the relationship between serum leptin and plasma insulin levels in obese and lean Chilean women. MATERIAL AND METHODS: One hundred forty five women, aged 20 to 60 years old, were studied. Weight, height, waist and hip circumference, fasting blood glucose, insulin and leptin levels were measured. Insulin resistance was assessed using the homeostasis model assessment. The relationship between different variables was determined using multiple linear regression, variance analysis and non parametric correlation. RESULTS: Leptin serum concentrations were positively correlated with body mass index, insulin plasma levels and degree of insulin resistance. The association of leptin with insulin was independent of body mass index and persisted after adjustments by body fat distribution and age. CONCLUSIONS: Insulin and insulin resistance are associated to high blood leptin levels and this association is independent of the degree of adiposity and body fat distribution.

Adult↗
PubMed2000

Double-blind, randomized, placebo-controlled pilot study with anapsos in senile dementia: effects on cognition, brain bioelectrical activity and cerebral hemodynamics.

The aim of this study was to evaluate the effects of two doses of anapsos in comparison with placebo on cognitive performance, brain bioelectrical activity pattern and cerebral hemodynamic parameters in patients with mild to moderate senile dementia of vascular type and Alzheimer type. Forty-five patients (age 73.8 +/- 7.6 years; range 56-89 years) with mild to moderate senile dementia (Global Deterioration Scale: stages 3-5) of the vascular (VD; n = 22) or the Alzheimer type (AD; n = 23) were included in a double-blind randomized placebo-controlled clinical trial. After a 2-week period of drug washout, patients were treated with placebo (n = 15; age 72.7 +/- 7.5 years), 360 mg/day of anapsos (n = 15; age 75.5 +/- 7.2 years), or 720 mg/day of anapsos (n = 15; age 73 +/- 7.7 years) for 4 weeks (28 days). At baseline and after the 4-week period of double-blind treatment, cognitive performance, brain bioelectrical activity power and blood flow hemodynamics in the middle cerebral arteries were evaluated with ADAScog, brain mapping and transcranial Doppler ultrasonography, respectively. Patients receiving 360 mg/day of anapsos showed a significant improvement in cognitive performance after treatment (ADAScog scores: p < 0.05) that was not observed in patients treated with placebo or 720 mg/day of anapsos. As compared to placebo, anapsos (360 mg/day) induced a significant improvement in ADAScog scores in mild senile dementia patients (p < 0.01) and in the subset of patients with AD (p < 0.05). Anapsos (360 mg/day) also increased cerebral blood flow velocities in left and right middle cerebral arteries in the subgroup of AD patients, whereas with the dose of 720 mg/kg this increase was only observed in the left side. Patients treated with anapsos (360 mg/day) showed a decrease in relative delta power and an increase in relative theta and alpha brain bioelectrical activity frequencies, indicating an acceleration of the EEG pattern. The present results show that anapsos (360 mg/day) improves cognitive performance, cerebral blood perfusion and brain bioelectrical activity in patients with senile dementia. These effects of anapsos were more marked in demented patients with mild mental deterioration and/or with dementia of the Alzheimer type.

Adjuvants, Immunologic↗
PubMed1999

Modeling of air pollution and its relationship with mortality and morbidity in Madrid, Spain.

OBJECTIVE: Evaluation of the association between air pollution and mortality and morbidity is becoming ever more complex owing to changes in inner-city air pollution, marked by decreasing values for all main pollutants save those associated with traffic. This has led to the need for the study of new epidemiological scenarios in which most pollutants are below guideline values. Nonetheless, the health effects are significant. METHODS: This report presents the results of a statistically based model for real-time forecasting of mortality and morbidity in Madrid, with meteorological and pollution series serving as inputs. RESULTS AND CONCLUSIONS: Not only did the models perform well with correlation coefficients between predicted and observed values (r = 0.683 for mortality, r = 0.681 for morbidity), but they enabled quantification of the impact of air pollution on mortality and morbidity (with increases ranging from 1. 8% to 12% for mortality and from 2.3% to 18% for morbidity for a 25-microg/m(3) increase in pollutants). Moreover, attention should be drawn to the observation that the model proved to be easy to implement and operate on a routine basis.

Air Pollution↗
PubMed1999

Implication of soluble and membrane HLA class I and serum IL-10 in liver graft acceptance.

Membrane HLA class-I expression (mHLA-I), soluble HLA class-I antigens (sHLA-I) and interleukin (IL)-10 are different factors implicated in the special acceptance of liver allograft. In this study, pre- and post-operative levels of mHLA-I in peripheral blood lymphocytes (PBL) and serum sHLA-I were analyzed in 86 liver transplants, immunosuppressed with Cyclosporine-A, methylprednisolone and azathioprine, and classified into acute-rejection (AR, n = 28) and non-acute-rejection (NAR, n = 58) groups. Serum IL-10 was studied in 47 recipients (AR-group, n = 16 and NAR-group, n = 31). Pre-transplant values of mHLA-I and sHLA-I showed a bimodal distribution (high/low) in NAR-recipients, but in AR-patients were mainly included in the low expression/secretion zone (mHLA-I, p < 0.02 and sHLA-I, p < 0.05). Consequently, average pre-transplant mHLA-I (868 +/- 109 versus 998 +/- 123, p < 0.05) and sHLA-I (1.3 +/- 0.4 versus 2.02 +/- 0.7 microg/ml, p < 0.01) was lower in the AR- than in the NAR-group. After transplant both parameters decreased in the NAR-group, but increased in AR-recipients previous to and on rejection diagnosis day. Additionally, serum IL-10 levels were significantly higher (p < 0.01) in the NAR than in the AR-group during the first 24 h post-transplant. In conclusion, low pre-transplant mHLA-I and sHLA-I levels pre-dispose liver recipients to acute rejection, whereas early post-transplant increases of serum IL-10 appear to be related to a good liver allograft acceptance.

Cell Membrane↗
PubMed1999

Comparison of the performances of TCu380A and TCu380S IUDs up to five years.

A modification of the TCu380A IUD to create the model TCu380S was introduced many years ago. The TCu380S utilizes copper sleeves that are flush in the plastic and are set at both ends of the horizontal arm. The objective of this study is to compare the clinical performance of the TCu380A and the TCu380S IUDs, especially regarding contraceptive performance and expulsion, in a cohort of women who had one of these two devices inserted at random. This paper presents the results up to 5 years of use. A total of 1568 women were enrolled: 806 women received a TCu380A and 762 women received a TCu380S IUD. The performance was evaluated by life-table analysis and significance between rates was tested by the method of log-rank. The cumulative pregnancy rate was low in users of both models of IUD but lower in users of the TCu380S model through the 5 years of use, without statistical significance. Expulsion was significantly higher in users of the TCu380S model during the five years of use. The other reasons for discontinuation were similar for both devices and did not show statistical significance. The continuation rate was significantly lower in users of the TCu380S model in the first and second years of use. Both devices presented a very low pregnancy rate and TCu380S presented a lower pregnancy rate than the TCu380A, although without statistical significance.

Adolescent↗
PubMed1999

Expanding contraceptive choice: findings from Brazil.

This article presents findings from a participatory action research project in a municipality in southern Brazil that models a new and holistic approach to broadening women's contraceptive choices. The project encourages a collaborative process between researchers, community members, and public health managers to diagnose service-delivery problems, to design and implement interventions, and to evaluate their effectiveness. Findings from the baseline evaluation revealed major constraints in availability of and access to family planning and reproductive health services for women, as well as severe deficiencies in quality of care. Interventions designed to address these weaknesses, bound by the limited resources of the public sector, focused on training, restructuring of providers' roles and service-delivery patterns, the management process, the creation of a referral center, and the introduction of injectables, vasectomy services, and a program for adolescents. Evaluation results show the project's considerable impact in broadening reproductive options, although not all issues, especially those related to sustainability, have been resolved.

Adolescent↗
PubMed1999

[outbreak of invasive pulmonary mycosis in neutropenic hematologic patients in relation to remodelling construction work].

BACKGROUND: An increase was observed in the number of cases of invasive pulmonary mycosis in neutropenic hematologic patients coinciding with construction work being carried out in the Hospital Clínico San Carlos (Madrid, Spain). The aim of this study was to confirm the existence of an outbreak, identify the factors related and adopt adequate control measures. METHODS: A descriptive, epidemiologic, environmental microbiologic study was performed. The incidence of cases in the study period and a control period was compared. Air samples were collected in the affected area and other areas of hospitalization not related to the construction work. The ventilation system of the Hemalotogy Isolation Unit (HIU) was also sampled. The control measures undertaken included: hermetic sealing of the construction work adjacent to hematology followed by transfer of the patients to another floor of the hospital. RESULTS: The existence of an outbreak was confirmed (significant increase in the incidence, p = 0.017). Eleven cases and one death by massive hemoptisis were reported. The mean total fungal count and to Aspergillus spp were 120 and 35 UFC/m3, respectively in the hematologic hospitalization area adjacent to the construction work and 37 and 5 UFC/m3 in other areas (p < 0.001). Contamination was detected in the ventilation system of the HIU by A. fumigatus (125 UFC/m3 of air from the interior of the conduct). CONCLUSIONS: An elevated number of fungal spores found in samples from the hematologic hospitalization area as well as no further new cases being reported following the transfer of the patients suggest that the outbreak was related to the adjacent construction work being carried out.

Disease Outbreaks↗
PubMed1998

X-PEEM Study on Surface Orientation of Stylized and Rubbed Polyimides.

X-ray photoelectron emission microscopy (X-PEEM) was used to study the surface orientation of stylized and rubbed polyimide thin films. Using soft X-rays produced by a synchrotron light source, this technique combines high spatial resolution imaging with near-edge X-ray absorption fine structure (NEXAFS) spectroscopy to yield information on the surface orientation of the films. Stylizing is an ideal model of the rubbing process since the local stress acting on the polyimide to orient the molecules can be calculated. The minimum normal stress necessary to orient the surface of BPDA-PDA films was found to be 45 MPa much lower than the bulk yield stress of 200-300 MPa. Studies of the polyimide films oriented by the conventional rubbing method showed lateral inhomogeneities in the orientation of the polymer at the surface.

Journal Article↗
PubMed1998

[Prospective randomized trial of meropenem versus cefotaxime and metronidazole in the treatment of intraabdominal infections].

BACKGROUND: The empiric antibiotic treatment of intraabdominal infections is in constant evolution. Monotherapy appears to be a desirable goal because of the simplicity of its administration, lack of toxic effects and wide spectrum. PATIENTS AND METHODS: A multicentre, prospective, randomized, open study was carried out to compare two antibiotic regimens in the treatment of intraabdominal infections in patients undergoing surgery. Ninety-eight consecutive patients were randomly allocated into two groups. One group (GM, n = 51) received meropenem (1 g/8 h) and the other (GCM, n = 47) a combination of cefotaxime (2 g/8 h) plus metronidazol (0.5 g/8 h). Clinical and bacteriological responses were assessed at the end of treatment and at 2-4 weeks. RESULTS: The severity of patients as assessed by the APACHE II score was similar in both groups (GM: 7.2 and GCM: 8.1). Three patients in each group could not be evaluated due to premature interruption of treatment or deviation from the protocol. The mean duration of treatment was 7.4 days in GM and 7.9 days in GCM. A satisfactory clinical response was obtained in 95% of patients in both groups. 31 patients (61%) in GM and 26 patients (55%) in GCM were bacteriologically evaluable. Bacteriological erradication was achieved in 94% of patients in GM and in 92% of patients in GCM. CONCLUSION: Meropenem is a good alternative for single antibiotic therapy in intraabdominal infections of moderate severity.

Abdomen↗
PubMed1998

Recognizing the reversible nature of child-feeding decisions: breastfeeding, weaning, and relactation patterns in a shanty town community of Lima, Peru.

Researchers have normally considered weaning to be a non-reversible event. To determine the validity of this assumption, we interviewed 36 mothers of toddlers who were living in a poor shanty town of Lima, Peru. Data from 32 women were complete and used in this analysis. Mothers described their beliefs, practices, and decisions about breastfeeding, weaning, and relactation (the reintroduction of breastfeeding after weaning). We recorded attempted weaning events if the mother reported (1) purposefully not breastfeeding with the intention to wean, or (2) carrying out an action that was believed to cause the child to stop breastfeeding. Using a constant comparative approach, references to child-feeding decisions were coded, categorized, and analyzed. All mothers breastfed for at least 12 months; the median duration of breastfeeding was 25 months. There were several different patterns of child-feeding. Thirteen women never attempted to wean their children or had weaned on the first attempt. The majority (n = 19) of women, however, attempted to wean their children - some as early as 3 months of age but relactated between less than 1 day and 3 months later. Factors that influenced feeding decisions were primarily related to maternal and child health, and maternal time commitments. Children were weaned when there was a perceived problem of maternal health or time commitments and child health was not at risk of deterioration. Mothers postponed weaning because of poor child health. The primary reason for relactation was a child's negative reaction to weaning (e.g., incessant crying or refusal to eat). Personalities of the mother and child were important determinants of feeding decisions. These results demonstrate that maternal and child factors jointly influence child-feeding decisions and that these decisions are easily reversed. As relactation is culturally acceptable, health practitioners should consider recommending relactation when children have been prematurely weaned and human milk would improve their nutritional and health status.

Adult↗
PubMed1998

Daily mortality in Madrid community 1986-1992: relationship with meteorological variables.

Daily mortality displays a seasonal pattern linked to weather, air pollution, photoperiod length, influenza incidence and diet, among which temperature ranks as a leading cause. This study thus sought to assess the relationship between temperature, relative humidity, wind speed and mortality in the Madrid Autonomous Region (Spain) for the period January 1986-December 1992, controlling for the effects of air pollution and influenza incidence. Daily data on maximum, minimum and 24-hour mean temperature, relative humidity and wind speed were matched against daily mortality. Transfer function was identified using the Box-Jenkins pre-whitening method. Multivariate time series regression models were used to control for the confounding effects of air pollution and influenza incidence. Separate seasonal analyses were carried out for winter and summer periods. A J-shaped relationship between outdoor temperature, relative humidity and daily mortality was found. Mortality proved to be inversely related to cold temperature (4- to 11-day lag) and directly related to warm temperature (1-day lag). High relative humidity during summer periods was negatively related to mortality. Thermal variation ascribable to Madrid's mesothermal Mediterranean climate was strongly related to daily mortality, even where air pollution and influenza incidence were controlled for.

Age Distribution↗
PubMed1998

[Polymerase chain reaction for rapid detection and serotyping of dengue virus in clinical samples].

This study describes the benefits of using reverse transcriptase polymerase chain reaction (RT-PCR) for the rapid detection and typing of dengue virus in clinical samples. Twenty-seven serum specimens from patients with dengue fever and dengue hemorrhagic fever in Colombia, Nicaragua, and Panama were directly subjected to RT-PCR for the detection of dengue virus. The resulting double-stranded DNA product was typed by a second round of PCR amplification (nested PCR) with type-specific primers, viral culture/indirect immunofluorescence (IIF), and enzyme-linked electroimmunoassay for IgM anti-dengue antibodies. The amplified virus genome was detected and typed within 8 hours. Nested RT-PCR, using viral culture and IIF as the gold standard, showed 100% sensitivity; 78% specificity; 69% positive predictive value, and 100% negative predictive value. It is noteworthy that two of the specimens whose results were positive with nested RT-PCR and negative with viral culture showed specific IgM antibodies. The results of the RT-PCR were in close agreement with those obtained through viral culture. This suggests PCR can greatly facilitate the rapid and early diagnosis of dengue infection.

Colombia↗
PubMed1998

[Microalbuminuria, lipid changes and coronary heart disease in non-insulin-dependent diabetics].

BACKGROUND: Microalbuminuria could be a possible coronary risk factor: AIM: To study the association between microalbuminuria, serum lipid levels and coronary heart disease in non-insulin-dependent diabetics. PATIENTS AND METHODS: We studied 104 non-insulin-dependent diabetics, who were separated in four groups according to the presence of microalbuminuria, defined as a 24 h albumin excretion of 30-300 mg/24 h and according the history of coronary artery disease. Total, HDL and LDL cholesterol, triglycerides, alpha, beta, prebeta lipoproteins, lipoprotein (a), apoproteins A and B were measured in all. RESULTS: Twenty patients with and 32 without coronary artery disease had normal albumin excretion and the same number of patients had a urinary albumin 30-300 mg/24 h. All four groups were comparable in terms of metabolic control, nutritional status, blood pressure and creatinine levels. Patients with coronary artery disease had higher urinary albumin excretion than patients without the disease 91 (32-173) and 34 (5-97) mg/24 h respectively p < 0.01. Patients with coronary artery disease and microalbuminuria had higher triglycerides, beta, pre beta lipoproteins, Apo B, Lp(a) and lower Apo B and alpha lipoproteins. This group also had a higher frequency of abnormal pre beta and alpha lipoprotein levels, when compared with coronary patients with normal albumin excretion. In coronary patients there was a positive association between urinary albumin levels and triglycerides (r = 0.24), pre beta lipoproteins (r = 0.27) and Apo B (r = 0.3); there was also a negative association with HDL cholesterol (r = 0.25) and alpha lipoproteins (r = -0.41). CONCLUSIONS: In this group of non-insulin-dependent diabetics, an association among microalbuminuria, abnormal serum lipid levels and coronary artery disease was detected.

Albuminuria↗