Biomedical subjects

J Rivera

Publications and source records attributed to J Rivera.

At least 289 records · Page 16Linked to original sources

PubMedDate not supplied

Oestrogen and progesterone receptors in human term placenta. Measurement by binding assays and immunological methods.

Oestrogen and progesterone receptors have been implicated in human placental steroidogenesis, but studies developed to measure their concentration in this tissue at term yielded discrepant results. Potential inaccuracy of the binding assays, the technique used in previous studies, might influence the discrepancy. In the present study, oestrogen and progesterone receptors were investigated by two different approaches: binding assays with radiolabelled ligand and immunoassays with monoclonal antibodies against receptors. Binding assays included techniques to quantify free and occupied sites in both the cytosolic and nuclear fraction. Conditions intended to block or decrease potential causes of inaccuracy, such as proteolysis or thermal denaturation of the sites, were included in the assays. Cytosolic specific binding was measured by two different techniques, dextran-coated charcoal and hydroxylapatite, whereas nuclear sites were studied on salt-extracts and by exchange. Negative or moderately positive results were obtained for either oestrogen or progesterone receptors, but high levels of non-specific binding made the technique unreliable. Immunoassays included the use of two techniques, histochemistry and enzyme-linked-immunosorbent-assay (ELISA). Both frozen and paraffin (Bouin solution or buffered formalin as fixatives) sections were stained with monoclonal antibodies against the oestrogen receptor. Results were always negative in all cases. Levels of oestrogen and progesterone receptors were measured in either cytosol or nuclear extracts by ELISA. This technique was highly sensitive and reproducible. Results were negative for both the cytosolic and nuclear fractions of oestrogen receptors. For progesterone receptors, low positivity was obtained in either crude (3.2 +/- 0.4 fmol/mg protein, mean +/- s.e.) or ammonium sulphate precipitated cytosols (12.6 +/- 3.5 fmol/mg protein, mean +/- s.e.), whereas the values for nuclear extracts were 62.0 +/- 9.0 fmol/mg DNA (mean +/- s.e.). We conclude that: (1) oestrogen receptors could not be detected in human term placenta by the methods used in this study, and (2) low levels of progesterone receptors were detected in both cytosolic and nuclear extracts.

Antibodies, Monoclonal↗

PubMedDate not supplied

Demonstration of P29, an oestrogen receptor-associated tumor marker, in human term placenta.

A Mr29,000 serine phosphoprotein (P29) related to oestradiol receptor was studied in human term placenta with the use of a specific monoclonal antibody (D5). D5 was used with two different methods, immunohistochemistry and immunoradiometry. For immunohistochemistry, an indirect immunoperoxidase method was chosen to detect P29 in methacarn-fixed, wax-embedded sections. P29 was mostly confined to the syncytiotrophoblast surrounding placental villi, staining being positive in both cytoplasm and nuclei. The stroma of villi was negative. Content of P29 was uniformly high in crude placental cytosol, as measured by immunoradiometry assays. Specificity of D5 against P29 in placenta was tested by an immunoblotting technique. This showed a single band corresponding to a molecular weight of 29 kDa. The biological meaning of the finding is unknown at present.

Antibodies, Monoclonal↗

PubMedDate not supplied

The Spanish dioxin inventory part I: Incineration as municipal waste management system.

The main objectives of the Spanish dioxin inventory and the incidence of municipal waste incinerators in the PCDD/Fs releases in the period from January 1997-November 1999 are presented. Preliminary data about the stack emission levels, fly ashes and slags as solid residues and the PCDD/Fs input in the USW are also presented to elaborate an initial balance for the incineration sector. A great decrease, from 20 to 1.2 g I-TEQ/y, from incineration gas emissions has been observed since 1996. The preliminary balance in the MWI sector suggests an overall PCDD/Fs destruction. The calculated emission factor, 1.06 microg I-TEQ/Mg, indicates a high quality of the air pollution control systems. The assumption of PCDD/Fs in the USW permits an initial evaluation of other waste management systems.

Air Pollutants↗

PubMedDate not supplied

Determination of PCDF/PCDD in sludges from a drinking water treatment plant influence of chlorination treatment.

A preliminary study to assess the origin and evolution of polichlorodibenzofurans (PCDFs) and polichlorodibenzo-p-dioxins (PCDDs) in a drinking water treatment plant (DWTP) was undertaken. Samples of coagulation sludges and exhausted granular activated carbon (GAC) were collected from a DWTP. Owing to the similar congener profiles obtained from sludges and GAC, a subsequent study of chlorination influence was carried out. Sludge samples from a treatment with and without the chlorination step were analysed. A complementary study of the PCB content was made. The results obtained did not reveal a marked influence of chlorination in the formation of PCDFs/PCDDs.

Benzofurans↗

PubMedDate not supplied

Levels of PCDD/Fs in soil samples in the vicinity of a municipal solid waste incinerator.

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were determined in 24 soil samples collected near a municipal solid waste incinerator (Tarragona, Catalonia, Spain). Soil samples were obtained at various sites within 1.5 km from the stack. Total PCDD/F concentrations ranged from 0.225 to 5.80 ng TEQ/kg dry matter (d.m.) with a median value of 0.799 ng TEQ/kg and a mean value of 1.080 ng TEQ/kg. No remarkable PCDD/F contamination was found. The results were consistent and even lower than those reported in other international studies. Principal Component Analysis and hierarchical cluster analysis were used to compare these soil samples with a set of 10 additional samples collected outside the influence of the plant. Principal Component and hierarchical cluster analyses of soils in the vicinity of the incinerator provide patterns of PCDD/Fs quite similar from those obtained in soils collected far from the influence of that facility.

Benzofurans↗

PubMedDate not supplied

Dioxin mass balance in a municipal waste incinerator.

A dioxin mass balance in an Spanish municipal waste incinerator (MWI) is presented. Input and output inventories from two sampling collection episodes including the analysis of PCDD/PCDF in urban solid waste (USW), stack gas emissions, fly ash and slag are reported. In one collection the levels of USW were around 8 pg I-TEQ/g and non-thermal destruction was observed overall. In the other collection the levels of USW were higher (around 64 pg I-TEQ/g) and the dioxin balance revealed a thermal destruction. Analysis of the different waste materials (textile, organic, plastic, wood and paper) was performed separately and the textile samples presented the highest levels.

Benzofurans↗

PubMedDate not supplied

[Variation in the number of diagnostic analyses and tests in a hospital outpatient consulting clinic].

OBJECTIVE: To analyze the variation in the number of diagnostic test orders after physicians have been made aware of the need to order only the necessary tests for adequate patient diagnosis. MATERIAL AND METHODS: The study was done in a prospective manner in 3 successive steps during which 750 first-visit patients attending in an outpatient rheumatology clinic at a general hospital were analyzed. In the first step (baseline) data were collected without the physicians' knowledge. The results of the study were later presented at a grand round. In the second step (intervention) data were collected again, this time with the physicians' knowledge. A final data collection (control) was carried out 6 months later without physicians' knowledge again. RESULTS: In the baseline step 2.355 orders with a mean of 9.42 +/- 5.5 order/patient were done. In the intervention step, there was a reduction of 1,946 orders with a mean of 7.78 +/- 4.48 (p < 0.001). Six months later, in the control step, the number of orders was reduced to 1.806 with a mean of 7.22 +/- 5.16 orders/patient, with a 23.3% saving compared with the baseline step (p < 0.001). Also, significant differences were found in the number or orders among physicians at each step. Reduction was observed in every kind of diagnostic test. CONCLUSIONS: A considerable reduction of 23.3% in the number of analysis and diagnostic tests can be obtained if physicians are made aware of the need to order only the necessary tests for patients' diagnostic. This strategy may result in a significant containment in the growing health care cost we suffer nowadays.

Adult↗

PubMedDate not supplied

Mentally ill chemical abusers in residential treatment programs: effects of psychopathology on levels of functioning.

Measures of psychopathology among mentally ill chemical abusers (MICAs) were examined as predictors of levels of functioning in two types of community based, residential programs: therapeutic community (TC) and community residence (CR). Non-significant associations were generally observed between scales of psychiatric symptoms (e.g., depression, psychotic ideation, cognitive disorientation, and hostility) and counselors' ratings of the residents' capacity to meet the social and interpersonal expectations of the programs (e.g., personal care, involvement in interpersonal relationships, and development of work skills). The study suggests that individuals with moderately severe psychopathology can be successfully engaged in residential treatment, even in programs with relatively high expectations for interpersonal involvement and functioning, such as the therapeutic community.

Activities of Daily Living↗

PubMedDate not supplied

In vitro analysis of platelet concentrates stored in the presence of modulators of 3',5' adenosine monophosphate, and organic anions.

The storage of conventional platelet concentrates (PCs) under standard blood bank conditions is limited to five days, in part because longer storage periods lead to increasing damage in platelet integrity and functionality. The growing demand of PCs for clinical use, raises the interest to develop agents that would potentially permit a more extended period of storage. We have evaluated and compared the in vitro quality of PCs treated with: (1) Modulators of levels of cAMP (PGE1, foskolin, theophylline and isobutyl-methyl-xanthine [IBMX]); and (2) organic anions that function as alternative substrates of platelets (pyruvate and acetate). Platelet rich plasma (PRP) from pools (n = 6) of PCs was distributed into storage bags, and the agents to be tested were added, using saline as a control substance. PCs were stored at 22 degrees C with continuous agitation for up to 10 days. At 0, 5 and 10 days of storage, samples were analyzed for platelet counts, mean platelet volume (MPV), metabolic markers, and expression of glycoproteins (GPs). The addition of modulators of levels of cAMP, at the concentration used in the study, did not lead to substantial improvement in the parameters being evaluated, with respect to those in control units. The supplementation with organic anions, while not affecting the surface levels of GPs, favored the maintenance of metabolic values, such as pH, PCO2, and bicarbonate concentrations, as well as the preservation of MPV (p values < 0.05 respect to control units both at 5 and 10 days of storage). Our results indicate that while the use of modulators of levels of cAMP do not provide substantial benefit in the prevention of platelet storage lesions, organic anions have some advantageous effect in the storage promoted metabolic changes of PCs. These data might be considered when designing strategies to improve PC storage.

1-Methyl-3-isobutylxanthine↗

PubMedDate not supplied

Prothrombotic genetic risk factors in patients with coexisting migraine and ischemic cerebrovascular disease.

The role of hemostatic elements in stroke has been clearly defined but several prothrombotic polymorphisms of hemostatic factors, important for other thromboembolic disorders, seem not to be very significant in stroke. Recently, the high prevalence of factor V Leiden in patients with stroke and a history of migraine has suggested an association between migraine and prothrombotic genetic risk factors. Stroke being a multifactorial disease, the aim of this study was to test whether prothrombotic tendencies increase the risk of stroke in patients with migraine. We determined the prevalence of four prothrombotic genetic risk factors (factor V R/Q 506, factor II 20210 G/A, decanucleotide insertion/deletion in the factor VII promoter, and the platelet HPA-1 alloantigen system) in 17 patients with coexisting ischemic cerebrovascular disease and migraine, 107 patients with ischemic cerebrovascular disease, 106 patients with migraine, and 202 control subjects. Genotyping for all polymorphisms analyzed in our study were performed after specific genomic polymerase chain reaction, and confirmed by single-strain conformation polymorphism analysis. In the group of patients with coexisting ischemic cerebrovascular disease and migraine, the prevalence of prothrombotic genotypes (factor V Leiden, 5.8%; factor II 20210 A, 0%; factor VII A1, 70.6%; and HPA-1b, 35.3%) was similar to that obtained in all other groups. We can conclude that the studied polymorphisms do not seem to be associated with the development of ischemic cerebrovascular disease in those patients with migraine.

Adult↗

PubMedDate not supplied

Detection of some organochlorine pesticides in cow's milk.

This monitoring study of 192 samples of cow's milk collected from the central region of Veracruz state was conducted to determine the contamination levels of organochlorine pesticides. The results obtained for mean DDT and HCH levels were 0.057 and 0.098 mg/kg respectively expressed on fat basis and are within FAO tolerances and similar to those found in other tropical countries.

Aldrin↗

PubMedDate not supplied

A perspective: regulation of IgE receptor-mediated mast cell responses by a LAT-organized plasma membrane-localized signaling complex.

BACKGROUND: To understand how the high-affinity IgE receptor (FcepsilonRI) communicates with downstream effectors, we focused on exploring the functional importance of the FcepsilonRI-mediated formation and localization of a signaling complex that contains the hematopoietic cell-specific scaffolding protein linker for activation of T cells (LAT) and the guanine nucleotide exchange factor Vav1. METHODS: Using the mast cell line RBL-2H3, we explored the localization of these proteins by confocal microscopy and cell fractionation. Additionally, the mechanism of function and the importance of LAT and Vav1 to mast cells was studied in genetically disrupted mice and in mast cells derived from their bone marrow. RESULTS: We found that LAT, Vav1 and the adapter molecule SLP-76 associated in detergent-resistant microdomains (lipid rafts) found in the plasma membrane upon FcepsilonRI stimulation. In the absence of LAT, mast cells showed a remarkable loss of the secretory response and reduced cytokine responses. Vav1 deficiency also affected secretion, although not to the extent of LAT deficiency, and inhibited IL-2 and IFN-gamma production. LAT- and Vav1-deficient mice showed reduced blood histamine levels after a systemic anaphylaxis challenge as compared to their normal counterparts. CONCLUSIONS: The results demonstrate that LAT is a central mediator in IgE receptor signaling by regulating multiple signaling pathways that affect mast cell degranulation and cytokine production. Vav1, a component of this LAT-containing signaling complex, regulates a specific subset of these responses.

Adaptor Proteins, Signal Transducing↗

PubMedDate not supplied

[Development and evaluation of food supplements for the education, health, and nutrition program].

OBJECTIVE: To develop and evaluate nutritional supplements destined to a program of social assistance. MATERIAL AND METHODS: In the design of the nutritional supplements a series of criteria were considered including nutrient composition, physicochemical properties and feasibility of production and utilization. Final products were initially evaluated to determine the level of acceptance in 40 children, 52 pregnant women and 62 lactating women in Mexico City. A community trial was also carried out to determine acceptance and consumption in 108 children and 128 women from a rural community in the state of Morelos. RESULTS: The specific formulation and technical processes of production of the nutritional supplements are presented. Products proved to be widely accepted, with average scores of 4.11-4.29 for the children's beverage, and 3.98-4.15 for a more viscous pap (range of scores was 1 to 5). Products for women received average scores from 4.75 to 5.70 in pregnant and from 4.8 to 5.4 in lactating women (range of scores from 1 to 7). In the community trial, supplements were very well accepted. Average consumption was > 75% among children and > 98% among women. Mean energy intake from supplements was 244 Kcal/day for women, and for children, 168 Kcal/day with the pap and 147 Kcal/day with the beverage. Consumption was consistent in all cases along the study. CONCLUSIONS: Nine nutritional supplements were developed and evaluated which comply with the necessary nutritional, physicochemical and hygienic characteristics for the target population, besides being relatively simple to prepare, and widely well accepted and consumed.

Adult↗

PubMedDate not supplied

[Acceptability of food supplements in pregnant or lactating women and children under 5 years of age].

OBJECTIVE: The present study explores the acceptance and consumption of nutritional supplements that form part of a governmental program to support nutritionally vulnerable groups. MATERIAL AND METHODS: Pregnant and lactating women, and mothers of malnourished toddlers, infants and children were interviewed. Data were collected, after introduction with an interview guide with an open-ended format, through face-to-face interviews conducted at home. Interviews were taped with previous informed consent. Analysis included topics and subtopics approached by the interviewed women. RESULTS: The studied population showed good acceptance to the supplement when offered as a drink. When considering benefits, pregnant women thought first of their baby's health than of their own and associated the possible advantages of the supplement to its "vitamin" contents. Acceptance of the flavors was largely influenced by previous contact to specific flavors. Children under 1 year of age preferred the liquid consistency and elderly children favored the puree. Most mothers considered that the offered amount was enough and there was the general impression that, as the time of the intervention elapsed, children showed greater appetite. The diet was not substituted by the supplement. CONCLUSIONS: Acceptance of the supplement may be improved by messages focusing on the well-being and health of the child and insisting on the benefits for the pregnant mother. Community health providers should be involved in supporting the program, recommending consumption and acceptance of the supplement. The identification by mothers of "vitamins" as part of the supplement may be used to reinforce the concept of beneficial effects associated to micronutrient supplementation. Qualitative evaluations should be performed as part of the assessment of community-based programs.

Child, Preschool↗

PubMedDate not supplied

The Fibromyalgia Impact Questionnaire: a validated Spanish version to assess the health status in women with fibromyalgia.

OBJECTIVE: To translate, adapt, validate and assess the sensitivity to change of a Spanish version of the Fibromyalgia Impact Questionnaire (FIQ-S). METHODS: The FIQ-S was adapted following the translation and back-translation methodology. Female patients with fibromyalgia (FM) were invited to participate. Reliability was analyzed by the Spearman correlation coefficient between test and retest. Internal consistency was checked by the Cronbach's alpha coefficient. Construct validity was analyzed comparing FIQ-S with: HAQ, FHAQ, SF-36, SCL90-R, and the visual analogue scale for pain. Sensitivity to change was assessed in an 8-week randomized trial of exercise therapy. Feasibility was analyzed by the time taken in completing the FIQ-S and the proportion of patients able to complete the questionnaire. RESULTS: Translation was concordant. Adaptation affected at 4 sub-items of physical function. One-hundred and two FM patients completed the protocol. Mean age was 48.7 years with a mean of 9.2 years of evolution. Test-retest correlations were between 0.61-0.85 (p < 0.0001). Internal consistency showed alpha = 0.82 for all items and alpha = 0.86 for the sub-items of physical function. Significant correlations (p < 0.0001) were found between the FIQ-S items and HAQ, FHAQ, SF-36 and SCL90-R. For patients treated with the exercise program, the pre-treatment FIQ-S score was 52.0 +/- 11.5 and the post-treatment score was 40.8 +/- 13.7 (p < 0.003). Mean time for completing FIQ-S was 3.3 minutes. In 4% of the patients external help was needed. CONCLUSION: The FIQ-S is a reliable, valid and responsive to changes questionnaire for measuring health status and physical function in Spanish speaking FM patients.

Adult↗

PubMedDate not supplied

[Indomethacin in the treatment of acute cholecystitis and biliary colic].

Prostaglandins GE2 produces on the gallbladder a rise in intraluminal pressure, an increase in in intraluminal secretion, improves gallbladder contraction and decreases its absorption capacity. In this study, patients who received indomethacin twice a day by rectum, showed a significant reduction in volume and area of gallbladder after 24 and 48 hours (P < 0.05). The gallbladder volume after 24 hours had SEM 9.13 cm3, 95% CI 55.28 + 73.49 (P < 0.05). Score pain reduction after 24 hours was also significant (P < 0.001). The patients who underwent the classical Baralcina treatment of one IV vial BID showed a reduction in diameter and area of gallbladder but this was not statistically significant (P < 0.10). Reduction of volume at 24 hours was SEM 5.34 cm3 95% CI - 64.72 + 76.60 P 0.10 NS; and at 48 hours SEM 3.5 cm3, 95% CI 59.52% + 66.52 P 0.40. Score pain reduction was only significant at 48 hours P 0.001. The number of patients without pain at 24 hours was significantly higher in the indomethacin group ESP 0.21; 95% CI 0.46 + 0.88 P 0.001. In conclusion indomethacin is a useful medication in the treatment of acute cholecystitis and biliary colic due to its anti-prostaglandin effect on the gallbladder.

Acute Disease↗

PubMedDate not supplied

[The use of microcomputers in the processing of complex hemodynamic data].

The use of a low-cost microcomputer in the clinical study of left ventricular diastolic function is described. Both left ventricular filling and compliance were studied by means of the simultaneous recording of left ventricular pressure and an echocardiogram displaying ventricular dimensions. A program was written to calculate ventricular volume every 40 msec and a volume-time diagram was obtained. The raw curve was smoothed with a second degree polinomial. The rate of change of ventricular volume (dV/dt) was obtained. Simultaneous left ventricular volume and pressure were plotted. The diastolic, exponential portion of the pressure-volume loop was used to calculate an index of ventricular stiffness at zero volume. It is concluded that a simple microcomputer, when conveniently programed, is able to perform the time-consuming mathematical operations involved in the clinical assessment of left ventricular diastolic function.

Cardiac Volume↗

PubMedDate not supplied

[Overweight in 12-49 year-old women and children under 5 years of age in Mexico].

OBJECTIVE: To estimate the association between some sociodemographic characteristics and the risk of obesity among 12-49 year-old women and children aged under five. MATERIAL AND METHODS: We analyzed data from Mexico's 1988 National Nutrition Survey, including information on 15 811 women of child-bearing age and 6 987 children aged under five years. We estimated the obesity prevalence rate ratios and confidence intervals for all the variables of interest. RESULTS: Preschool children living in the north and central regions of Mexico presented higher obesity prevalence rates than those living in the southeast (PR = 1.90, 95% CI 1.41-2.59 and PR = 1.91, 95% CI 1.41-2.59, respectively). The risk of obesity was positively associated to the educational level of the head of the household. The prevalence of obesity was greater among child-bearing age women living in the northern region of Mexico and in Mexico City (PR = 1.21, 95% CI 1.10-1.34 and PR = 1.16, 95% CI 1.05-1.28). The prevalence of obesity was also positively associated with the number of live births and negatively associated with the woman's educational level. CONCLUSIONS: It is necessary to implement obesity prevention programs among high risk groups.

Adolescent↗