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Biomedical subjects

A Gomez

Publications and source records attributed to A Gomez.

At least 55 records · Page 3Linked to original sources
PubMed1996

Soil and waste analysis for environmental risk assessment in France.

In France today, analysis of soil and waste after digestion by strong acids is a technique used for the estimation of environmental risks due to soil pollution and spreading of wastes on cultivated soils. The technique of digestion by strong acid accounts for total or 'near total' content of As, Cd, Cr, Cu, Hg, Ni, Pb, Se and Zn. Risk management based on these methods aims to minimize the risks, since the concentration limits are derived from the geochemical levels. However, this method of analysis gives no idea of the extent to which elements are really transferable or bioavailable. Analytical methods based on partial extraction are used to discern deficiencies in B, Cu, Fe, Mn and Zn in soil. These extractions are carried out using boiling water and EDTA or DTPA solutions. The extraction methods have been standardized for use in agriculture, but have not been tested for assessing the risks due to the pollution by trace elements. One partial extraction method has been standardized for the analysis of wastes. It uses successive water extractions. Researchers have studied different partial extraction methods for estimating the bioavailability of mineral pollutants. Some of them gave results which correlated well with the amounts taken up by plants. However, at present, no general frame of reference has yet been established for the interpretation of results on a broad scale.

Environmental Pollution↗
PubMed1996

Relationship between birth weight and awake blood pressure in children and adolescents in absence of intrauterine growth retardation.

This study was designed to examine the relationship between birth weight (BW) and ambulatory blood pressure in children and adolescents, born at term in absence of intrauterine growth retardation. Twenty-four hour ambulatory blood pressure monitoring (ABPM) was performed on 332 children (150 boys), aged from 6 to 16 years. Subjects were stratified by BW tertiles and age. ABPM was performed using SpaceLabs 90207 monitor during a regular school day. Blood pressure (BP) was measured every 20 min from 06:00 to 24:00, and thereafter every 30 min. Means of systolic BP (SBP) and diastolic BP (DBP) during 24 h, daytime (08:00 to 22:00), and nighttime (24:00 to 06:00) were calculated. Systolic and diastolic load was estimated as the percentage of measurements above the age- and sex-specific 95th percentile during the 24 h. BW was inversely related to daytime (SBP (P = .04) and SBP load (P = .04) when controlled for sex, current height, ponderal index (weight/height3), and age. The predictive values of daytime SBP throughout the pediatric age group in the two extreme tertiles of BW (lowest, 2.500 to 3.200 kg; and highest, 3.501 to 4.820 kg) were obtained from regression equations including SBP during activity period or SBP load and age. Children who had lower BW tended to have higher daytime SBP or SBP load at any age although this difference was not statistically significant. These differences became more evident as the subjects got older. BW is a determinant of daytime SBP even in the absence of intrauterine growth retardation. The influence of BW seems to increase with age.

Adolescent↗
PubMed1996

Mediastinal mass following chemotherapy in patients with Ewing sarcoma and osteosarcoma.

Thymic hyperplasia following combination chemotherapy for malignant disease is very uncommon in adolescents and adults. Our experience includes a thymic enlargement noted on the sequential computed tomography (CT) in three patients who were disease-free after chemotherapy for Ewing sarcoma (2) and osteosarcoma (1). The development of an anterior mediastinal mass after successful chemotherapy does not always imply relapse of malignant disease. To prevent inappropriate treatment, the possibility of benign aetiology must be considered.

Adolescent↗
PubMed1996

HLA-DPB1 polymorphism in seven South American Indian tribes in Colombia.

HLA-DPB1 allele frequencies were investigated in seven geographically and linguistically distinct Amerindian tribes of Colombia. Allele *1301 was found only in the Embera tribe living along the Pacific coast, while allele *0101 was found only in two individuals of the Wayuu tribe inhabiting the Guajira desert. Significant geographical variation was observed in the other two alleles (*1401 and *0402), which were found in all seven tribal groups. The possible reasons for this restricted polymorphism and the genetic diversity found in the investigation are discussed.

Alleles↗
PubMed1996

HLA antigens in Ameridian groups of two different linguistic families from Colombia.

Serological HLA types (A, B, C, DR and DQ loci) were studied in five different Indian tribes (Cubeo, Tucano, Coreguaje, Embera and Noanama) belonging to two distinct linguistic families. For all the MHC loci, the range of variation among the five tribes was enormous. Two tribes, Cubeo and Tucano, showed a wide spectrum of antigenic specificities which seemed to be due to admixture from non-tribal groups, while in the other three tribes the polymorphisms of various HLA loci showed restricted distributions. The gene frequency data, when converted to a kinship matrix and a two-dimensional eigenvector plot, indicated that members of the same linguistic family tend to have greater genetic affinity.

Colombia↗
PubMed1996

Alteration of left ventricular filling evaluated by Doppler echocardiography as a potential marker of acute rejection in orthotopic heart transplant.

To evaluate the changes in left ventricular (LV) filling associated with acute cardiac rejection, serial Doppler echocardiographic (ED) examination were performed on the same day as endomyocardial biopsy (EMB) in 40 patients who underwent orthotopic transplantation. The diameters and wall thickness of the left ventricle were measured. The indexes of LV filling in the following parameters were measured by pulsed Doppler: isovolumic relaxation time (IRT), peak early mitral flow velocity (V max E), and pressure half-time (PHT). The patients were classified into three groups on the basis of EMB: Group I (19 patients without rejection), Group II (11 patients with mild or moderate rejection), and Group III (10 patients with severe rejection). In Group III rejection was associated with a significant increase of posterior wall thickness (P < 0.05), with a decrease of IRT (P < 0.05), and an increase of V max E velocity (P < 0.01) in comparison with Group I. In Group II, Doppler indexes were not statistically significant in comparison with Groups I and II. In conclusion, in transplant patients, a diagnosis of acute rejection can be suspected in severe rejection by use of echocardiography when the diagnosis is based on a multiparametric evaluation of different ED indexes (m-mode and Doppler indexes). Doppler echocardiography is a method with an excellent specificity but insufficient sensitivity; this is due to the influence of recipient atrial contraction timing on Doppler indexes of LV filling.

Biopsy↗
PubMed1996

Primary antiphospholipid syndrome presenting as chronic thromboembolic pulmonary hypertension. Treatment with thromboendarterectomy.

Pulmonary hypertension may occur in the antiphospholipid syndrome as a result of recurrent pulmonary embolism or microthrombosis of pulmonary vessels. We describe 3 cases of primary antiphospholipid syndrome (APS) and cor pulmonale that fulfilled the criteria for chronic major vessel thromboembolic pulmonary hypertension. Pulmonary thromboendarterectomy was performed in all 3 patients and it was successful in 2. One patient died in the immediate postoperative period from hemorrhagic pulmonary edema. Chronic thromboembolic pulmonary hypertension should be added to the list of pulmonary vascular complications of primary APS. Despite its risk, pulmonary thromboendarterectomy represents a treatment option for this otherwise lethal condition.

Adult↗
PubMed1995

Expression of the SalI restriction-modification system of Streptomyces albus G in Escherichia coli.

The salIR and salIM genes of Streptomyces albus G encode the restriction endonuclease (ENase) and DNA methyltransferase (MTase) of the SalI restriction-modification (R-M) system. In S. albus G, the genes constitute an operon that is mainly transcribed from a promoter located upstream from salIR, the first gene of the operon. In addition, a second promoter, at the 3' end of salIR, allows independent transcription of the MTase gene. Expression of salIR and salIM in Escherichia coli was investigated. The ENase gene was not expressed in the heterologous host, probably due to inactivity of the main promoter of the salI operon. In contrast to salIR, salIM was functional in E. coli. Preliminary S1 nuclease mapping experiments suggest that the alternative promoter of the MTase gene can initiate transcription in the heterologous, as well as in the homologous host.

Cloning, Molecular↗
PubMed1995

Behavioral effects evoked by SKF 38393 and LY 171555 in adult cats.

The aim of the present work was to study the behavioral effects elicited in adult cats by the selective D1 agonist, SKF 38393, and the D2 agonist, LY 171555, comparing their effects with those evoked by apomorphine. In 10 adult cats, 0.5, 1.0, 4.0, and 8.0 mg/kg IP of SKF 38393 were administered at random. A dose-response effect was observed related to alertness, indifference, and locomotion. The overall effect of SKF 38393 was inhibitory. To the same 10 animals, LY 171555 in doses of 0.25, 0.5, and 1.0 mg/kg were injected IP. This drug had an excitatory and more complex effect than what was observed with the D1 agonist. Increases in locomotion, in alertness, indifference, fear, olfaction, pupillary dilation, hallucination, limb flicking, and head shaking were recorded. Apomorphine given to the same cats, in a dose equimolar to 1.0 mg/kg of LY 171555, elicited behaviors that resembled those elicited by the latter drug, but of a lesser intensity and duration. The interval between the different treatments was approximately 2 months. These results show clearly that the D2 receptor is the main dopaminergic receptor involved in the mechanism of production of most of the behavioral effects produced by some of the dopaminergic agonist drugs like apomorphine.

2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-ben↗
PubMed1995

Primary pulmonary hypertension in children: clinical characterization and survival.

OBJECTIVES: This study characterized mortality in a group of Mexican children (n = 18, mean [+/- SD] age 9.9 +/- 3 years) with primary pulmonary hypertension and investigated the factors associated with their survival. BACKGROUND: Primary pulmonary hypertension is a progressive, fatal disease of unknown cause. Establishing the diagnosis earlier in life may influence prognosis. METHODS: A dynamic cohort of children with primary pulmonary hypertension were enrolled between December 1977 and May 1991 and followed up through September 1992. Measurements included hemodynamic and pulmonary function variables in addition to demographic data, medical history and response to vasodilator treatment. We also compared the survival estimates of these children with those of our adult patients with primary pulmonary hypertension (n = 42, mean age 27.9 +/- 8.5 years). RESULTS: Baseline mean (+/- SD) pulmonary artery pressure was similar in children and adults (66 +/- 15 vs. 65 +/- 18 mm Hg, p = NS), but a higher cardiac index resulted in a lower mean pulmonary vascular resistance index in children (18 +/- 7 vs. 26 +/- 12 U/m2, p < 0.01). The proportion of patients who had a positive hemodynamic response to vasodilator treatment was higher in children than in adults (41% vs. 25%). Estimated median survival in children was 4.12 years (95% confidence interval [CI] 0.75 to 8.66) and 3.12 years in adults (95% CI 0.5 to 13.25, chi-square log-rank 0.81, p = NS). Elevated right atrial pressure (rate ratio 10.2) and decreased stroke volume index (rate ratio 32.9) were the only significant predictors of mortality (Cox proportional hazards model). CONCLUSIONS: Children with primary pulmonary hypertension have a poor survival expectancy, which does not appear to differ from that in adults with primary pulmonary hypertension. Mortality in childhood primary pulmonary hypertension is also associated with variables that assess right ventricular dysfunction.

Adult↗
PubMed1995

Atropine and glycopyrronium show similar binding patterns to M2 (cardiac) and M3 (submandibular gland) muscarinic receptor subtypes in the rat.

Atropine and glycopyrronium are frequently used for premedication to reduce oral and respiratory secretions and prevent bradycardia. Glycopyrronium is said to have similar antisialagogue effects, but is less likely to cause significant tachycardia than atropine. Different antimuscarinic receptor selectivity patterns could explain the differences. The aim of this investigation was to determine the possible selectivity of glycopyrronium for M2 and M3 muscarinic receptor subtypes. Muscarinic receptor subtypes in Wistar rat ventricle and submandibular gland homogenates were characterized with [3H]-N-methylscopolamine ([3H]-NMS) by ligand binding studies. Inhibition of [3H]-NMS binding by non-labelled compounds showed the following order: in rat ventricle: glycopyrronium > atropine >> otenzepad > hexahydrosiladiphenidol (HHSiD) > pirenzepine; in rat submandibular gland: glycopyrronium > atropine >> HHSiD >> pirenzepine > otenzepad. These were similar to the expected order of frequency of M2 and M3 subtypes, respectively. Glycopyrronium showed similarly high affinities for both M2 (Ki = 1.889 (SEM 0.049) nmol litre-1) and M3 (Ki = 1.686 (0.184) nmol litre-1) subtypes. Glycopyrronium bound to a homogeneous population of binding sites in both tissues and showed no selectivity for M2 or M3 muscarinic receptor subtypes.

Animals↗
PubMed1995

Four days' continuous infusion of cisplatin-5-fluorouracil and short daily infusion of high-dose leucovorin as induction chemotherapy for locally advanced head and neck cancer.

Cisplatin-fluorouracil (PF) is the most frequently used combination as induction chemotherapy (CT) for the treatment of locally advanced squamous cell head and neck cancer. This study was designed to evaluate the role of leucovorin (L) in the modulation of the therapeutic activity of PF continuously infused for 4 days. Between June 1990 and June 1992, stage III and IV previously untreated patients received PFL induction chemotherapy followed by surgery, radiotherapy, or both. The chemotherapy consisted of P 25 mg/m2, F 1000 mg/m2 both continuously infused for 4 days and L 250 mg/m2 infused for 2 hours before each daily infusion of PF. PFL was administered every 3 weeks for 4 cycles. The overall response rate at the completion of PFL was 91%, with 54% CR and 37% PR. Locoregional treatment was performed on 68 patients, 11 (16%) underwent surgery, 20 (29%) surgery plus radiotherapy, and 37 (54%) radiotherapy. Complete response status after both induction and locoregional therapy was 71%. Biopsies of the primary tumor or definitive resection specimens immediately after PFL therapy were available in 25 patients in CR. Pathological CR was found in 11 (44%). With a maximum follow-up of 44 months, the overall survival rate is 51% and the median survival has not been reached. PFL is highly active as induction chemotherapy. A randomized comparison between PF and PFL is necessary to define the place of leucovorin modulation in the treatment of head and neck cancer.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1994

Prognostic significance of serum CA 125 antigen assay in patients with non-small cell lung cancer.

BACKGROUND: The serum levels of CA 125 tumor-associated antigen in patients with lung cancer have been previously related to TNM stage, histologic type, and survival rate. In the current study, the prognostic information provided by the CA 125 antigen assay was analyzed. METHODS: Preoperative serum of CA 125 antigen was determined in 137 patients with non-small cell lung cancer. The assay was performed by means of a solid-phase enzyme-immunoassay test. The influence of CA 125 serum level on postoperative outcome was studied by a multivariate analysis, performed with Cox's proportional hazards regression model. RESULTS: Patients whose initial CA 125 level was higher than 15 U/ml had a 3.25-fold greater likelihood of relapse (95% confidence interval [CI], 1.7-6.21) (P < 0.001) and a 4.27-fold greater likelihood of deaths (95% CI, 2.42-7.55) (P < 0.001) due to cancer than patients with lower values. For patients with serum levels over 15 U/ml, the 36-month survival rate posttreatment was lower (67% versus 20%) (P < 0.001), as was the disease-free rate (64% versus 13%) (P < 0.001). After adjustment for TNM stages, histologic type, sex, and age, patients with CA 125 values over 15 U/ml continued exhibiting higher risk of relapse (hazard ratio, 2.2; 95% CI, 1.04-4.69) (P = 0.04) and higher risk of death (hazard ratio, 2.42; 95% CI, 1.29-4.54) (P = 0.006). CONCLUSIONS: CA 125 is an independent prognostic factor of survival and tumor relapse in non-small cell lung cancer. The preoperative serum level of CA 125 antigen is inversely correlated with the outcome figures. The authors suggest that CA 125 be included in any future multifactorial analysis of survival.

Adenocarcinoma↗
PubMed1994

Comparative analysis of the behaviors evoked by bromocriptine and quinpirole (LY 171555) in adult cats.

The aim of this work was to compare the behavioral effects of bromocriptine and quinpirole, two agonists of the D-2 dopaminergic receptor, either injected alone or combined with the D-1 dopaminergic receptor, SKF 38393. In ten adult mongrel cats the following experimental series were carried out: i) a dose-response study with bromocriptine administering 0.5-1.0-4.0 and 8.0 mg/kg s.c.; ii) a behavioral study injecting 4.0 mg/kg of bromocriptine plus 2.0 mg/kg of SKF 38393; iii) the same analysis administering 0.5 mg/kg of LY 171555 plus 1.0 mg/kg of SKF 38393, compared with the same dose of LY 171555 plus 4.0 mg/kg of SKF 38393; iv) an analysis of the behavioral effects of 8.0 mg/kg of bromocriptine compared with 1.0 mg/kg of quinpirole. The main findings were: i) bromocriptine injected, in four different doses evoked decrease in locomotion, and increase in indifference, inappetence, pupillary dilation and limb flicks; ii) the combined administration of 4.0 mg/kg of bromocriptine plus 2.0 mg/kg of SKF 38393 did not elicit behavioral changes different to those produced by bromocriptine alone; iii) quinpirole (1.0 mg/kg) evoked more intense behaviors than bromocriptine (8.0 mg/kg); iv) comparing quinpirole injected alone with the combination of quinpirole plus SKF 38393, this latter treatment produced more intense behaviors than the former. It is concluded: i) SKF 38393 potentiates the behavioral effects produced by quinpirole; this potentiation was not found when bromocriptine was combined with SKF 38393 and ii) the more intense behavioral effect elicited by quinpirole compared with bromocriptine may be explained by the fact that the latter drug is a selective D-2 agonist, whereas the former one is an agonist of the D-2 and the D-3 receptors.

2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-ben↗