Search PubMed⌕ Search

Biomedical subjects

R Gomez

Publications and source records attributed to R Gomez.

At least 181 records · Page 10Linked to original sources
PubMed1977

TLC sensitivity of six modifications of Dragendorff's reagent.

The relative sensitivities of six modifications of Dragendorff's reagent were measured on TLC plates by spectrodensitometry, using compounds containing specific functional groups. A correlation between the structures of the compounds reactive to Dragendorff's reagents and the sensitivities of the reagents was made. Explanations for the variations in sensitivities between different modifications of Dragendorff's reagent are given.

Chromatography, Thin Layer↗
PubMed1976

Traumatic pseudoaneurysms: a review of 32 cases.

The management of 23 patients with traumatic pseudoaneurysms is presented. A pulsatile mass associated with pain was the usual presentation. Hypertension and hypovolemic shock from rupture are uncommon presentations but potential hazards of this lesion. Twenty-one pseudoaaeurysms were treated surgically. Resection with end-to-end anastomosis (eight patients), with graft replacement (one patient), with lateral repair (seven patients) was done. Hypothermia with circulatory arrest and external Dacron shunt were used to prevent visceral ischemia during high aortic occlusion. There were no mortalities or significant postoperative complications.

Adolescent↗
PubMedDate not supplied

Matrix metalloproteinases-9 in preterm and term human parturition.

OBJECTIVE: Spontaneous rupture of the fetal membranes occurs after the commencement of labor in 90% of cases. Recent evidence indicates that the process of parturition requires not only an increase in myometrial contractility and cervical ripening, but also degradation of extracellular matrix in fetal membranes (i.e., leakage of fibronectin into cervico-vaginal secretions). This study was undertaken to determine if parturition is associated with in vivo evidence of increased bioavailability of matrix metalloproteinases-9 (MMP-9) and its inhibitor, tissue inhibitor of metalloproteinases-1(TIMP-1). METHODS: A cross-sectional study was conducted with women in the following categories: 1) midtrimester (n = 25); 2) preterm labor and intact membranes in the absence of intraamniotic infection (n = 78); 3) term not in labor (n = 25); and 4) term with intact membranes in labor (n = 25). MMP-9, and TIMP-1 were measured using sensitive and specific immunoassays. RESULTS: 1) Spontaneous labor at term was associated with a significant increase in MMP-9 but not in TIMP-1.2) Women with preterm labor who delivered prematurely had significantly higher concentrations of MMP-9 but not TIMP-1 in amniotic fluid than those with preterm labor who delivered at term. 3) The concentrations of TIMP-1 decreased with advancing gestational age. In contrast, MMP-9 concentrations did not change with advancing gestational age. CONCLUSIONS: Spontaneous human parturition is associated with specific changes in the enzymatic machinery responsible for extracellular matrix degradation.

Amniotic Fluid↗
PubMedDate not supplied

P1(A2/Ra)-purinoceptors may mediate the stimulatory effect of adenosine and adenosine analogs on acid formation in isolated rabbit parietal cells.

The effects of adenosine (ADO) and its analogs 2-chloroadenosine (2CADO) and 5'-N-ethyl-carboxamido adenosine (NECA) on acid production, as measured by the [14C]-aminopyrine (AP) accumulation method, were studied in rabbit gastric parietal cells prepared by enzymatic dispersion and enriched by counterflow elutriation. ADO (1 microM to 1 mM), 2CADO (1 microM to 1 mM) and NECA (0.1 microM to 100 microM) caused significant concentration-related increases on AP uptake by resting parietal cells. The order of potency was NECA >> 2CADO > or = ADO. Histamine and dibutyryl-cAMP (db-cAMP), known secretagogues, stimulated AP accumulation. In both, histamine- and db-cAMP-stimulated parietal cells, ADO, 2CADO and NECA at the above concentration ranges induced concentration-related increases of the respective AP accumulation raised-rates. The rank order of potency in both stimulated conditions was: NECA > 2CADO >> ADO. Cimetidine, a well known H2 histamine receptor antagonist, at concentration of 100 microM caused potent inhibition of histamine-stimulated AP accumulation without affecting the stimulatory responses to db-cAMP. The increases of AP accumulation elicited by NECA, the most potent purine tested, in both resting and histamine- or db-cAMP-stimulated parietal cells were not significantly modified by cimetidine 100 microM. Theophylline (0.1 microM to 10 microM), a non-specific P1-purinoceptor antagonist, caused significant inhibition of the NECA responses in both resting and histamine-stimulated parietal cells. The concentration order of potency of theophylline was: 0.1 microM > 1 microM > 10 microM. These results suggest that there are P1(A2/Ra)-purinoceptors on rabbit parietal cells which mediate the stimulatory effects of adenosine and analogs on gastric acid production.

2-Chloroadenosine↗
PubMedDate not supplied

Social information processing in mild mentally retarded children.

This study examined the social information processing (SIP) skills of mild mentally retarded (MR) children using Dodge's model. Six sets of pictures depicting provocation situations were used to elicit measures of accuracy of interpretation to accidental and hostile cues, attribution of ambiguous cues, and hostile and nonhostile behavior responses to all three types of cues. MR children were compared to nonretarded groups matched for chronological age (CA-matched) and mental age (MA-matched) on these variables. Compared to both nonretarded groups, the MR group was less accurate in interpretation of accidental cues and more hostile in their responses to the ambiguous cues. The latter finding remained even after partialing out externalizing behavior problems. The results are discussed in terms of factors associated with SIP skills, and the assessment and treatment of MR children.

Aggression↗
PubMedDate not supplied

Characterization of the effects of adenosine, adenosine 5'-triphosphate and related purines on acid secretion in isolated rabbit gastric glands.

The influence of adenosine, AMP, ADP, ATP, the adenosine analogue L-PIA and the ATP analogue beta,gamma-methylene ATP, on gastric acid secretion, as measured by the aminopyrine accumulation method, in resting and histamine-stimulated glands isolated from rabbit gastric mucosa was studied. In resting glands, adenosine and its analogue L-PIA (10 microM-1 mM) caused significant concentration-related increases of the basal H+ secretion, whereas no changes were obtained in response to the other purines tested. In histamine-stimulated glands, adenosine, L-PIA and AMP (10 microM-1 mM) induced concentration-related increases of the H+ secretory rate, whereas ATP, beta,gamma-methylene ATP and ADP (10 microM-1 mM) produced concentration-related decreases of the H+ raised rate. The rank order of potency of the purine compounds in increasing the stimulated H+ secretion was: adenosine greater than L-PIA much greater than AMP, and in decreasing it was: ATP much greater than ADP greater than beta,gamma-methylene ATP. The stimulatory responses to adenosine were inhibited by theophylline (10 microM-100 microM) and caffeine (10 microM-1 mM); whereas, the inhibitory responses to ATP were significantly reduced by the well known prostaglandin synthesis inhibitor indomethacin (1 microM-100 microM). From the results it is concluded that in isolated rabbit gastric glands, purine compounds are effective modulators of the gastric H+ secretory process. The pattern of purine activity obtained suggests that the stimulatory responses, inhibited by methylxanthines, may be mediated via P1-purinoceptors, while the inhibitory responses, reduced by indomethacin, may be mediated via P2-purinoceptors.

Adenosine↗
PubMedDate not supplied

Detection of mRNA encoding H(1) receptor and iNOS by RT-PCR in autoimmune myocarditis with special reference to changes in heart contractility.

Cardiac tissue from autoimmune myocarditis mice was studied to evaluate the expression and biological activity of mRNA encoding H(1) receptor and iNOS. BALB/c inbred mice were immunized with heart protein and sacrificed at 20, 45 and 50 days post immunization. Heart contractility studies and RT-PCR assays were performed. Heart from autoimmune myocarditis mice show mRNA iNOS-related dysfunction with a decrease in heart contractility. This effect was accompanied with an increase production of cyclic GMP and was improved by treating autoimmune mice with an inhibitor of iNOS activity. In addition, autoimmune myocardium expressed an active histamine H(1) receptor mRNA coupled to phospholipase C. The activation of H(1) receptor by ThEA stimulated both phosphoinositide hydrolysis and heart contractility. Normal myocardium did not expressed neither iNOS mRNA nor H(1) receptor mRNA. In conclusions: the development of autoimmune cardiac dysfunction was associated with the expression of iNOS mRNA, cyclic GMP accumulation and the expression of an active histamine H(1) receptor mRNA with increase production of inositol phosphates. These protein emergence during the course of autoimmune myocarditis may be involved a distinct compensatory mechanism operating in this disease.

Animals↗
PubMedDate not supplied

Predictors of glycemic control in children with type 1 diabetes: the importance of race.

Diabetes is a common cause of kidney failure and blindness among young adults, particularly of African-American descent. Since glycemic control is a predictor of diabetes complications, we evaluated the impact of multiple factors including a special multidisciplinary management program on glycosylated hemoglobin in children with Type 1 diabetes. Data was collected from pediatric diabetes clinics in New Orleans, LA and Baltimore, MD. In New Orleans, hemoglobin A(1c) was higher in African-American patients 12. 5+/-3.3% (n=71) vs. 10.7+/-2.1% (n=80) in Caucasian children, p<0. 0001. Longer duration of diabetes was also associated with higher hemoglobin A(1c) in both races. The effect of race on hemoglobin A(1c) was independent of the influence of sex, insurance status, body mass index (BMI) z-score, and number of clinic visits. Covariate analysis with mean blood glucose levels indicated that higher hemoglobin A(1c) was attributable to higher mean blood glucose levels in African-American children. From the Baltimore data, a multidisciplinary intervention program led to improved total glycosylated hemoglobin for Caucasian patients but not for African-American children. Poorer glycemic control of African-American children is likely to predispose them to a higher likelihood of developing microvascular complications as they mature. Standard hospital-based multidisciplinary programming for diabetes management may have limited effectiveness in improving glycemic control of African-American children with diabetes. Innovative intervention programs are needed for these high-risk patients.

Adolescent↗
PubMedDate not supplied

Amniotic fluid interleukin-6 determinations are of diagnostic and prognostic value in preterm labor.

PROBLEM: The purpose of this study was to determine if amniotic fluid concentrations of the interleukin-6 (IL-6) are of value in diagnosis of microbial invasion of the amniotic cavity and in the prediction of failure of tocolysis, preterm delivery and perinatal morbidity and mortality. METHOD: Amniotic fluid was obtained by transabdominal amniocentesis from 146 consecutive patients admitted with the diagnosis of preterm labor and intact membranes. Fluid was cultured for aerobic and anaerobic bacteria as well as for mycoplasmas. Amniotic fluid IL-6 levels were measured using a monoclonal antibody-based enzyme-linked immunosorbent assay with a sensitivity of 0.03 ng/ml. Logistic regression and Cox's proportional hazards model were used to examine the effect of several variables on dichotomous outcomes or interval to delivery. RESULTS: Patients with a positive amniotic fluid culture had a significantly higher amniotic fluid IL-6 concentrations than patients with a negative culture (median 91.2 ng/ml, range 0.9 to 437 ng/ml versus median 0.4 ng/ml, range < 0.3 to 195 ng/ml, respectively; P < .0001). An amniotic fluid IL-6 concentration of greater than or equal to 11.3 ng/ml had a sensitivity of 93.3% (14 of 15) and a specificity of 91.6% (120 of 131). All patients with an amniotic fluid IL-6 concentration above 11.3 ng/ml and a negative amniotic fluid culture (N = 11) delivered preterm and all placenta available for examination (N = 7) had histologic evidence of chorioamnionitis. Amniotic fluid concentrations of IL-6 were an independent predictor of preterm delivery, amniocentesis-to-delivery interval and neonatal morbidity and mortality. Moreover, IL-6 concentrations added significant information to the prediction of these outcomes to that provided only by clinical information such as cervical dilatation, gestational age at admission or at delivery. CONCLUSION: IL-6 is a sensitive and rapid test for the detection of microbial invasion of the amniotic cavity and for identifying women at risk for spontaneous preterm delivery and neonates at risk for morbidity and mortality.

Adult↗