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Biomedical subjects

G Gómez

Publications and source records attributed to G Gómez.

At least 19 recordsLinked to original sources

Solid-phase extraction of prostanoids using an automatic sample preparation system.

A commercial automated solid-phase extraction system for cyclooxygenase arachidonic acid metabolites in urine samples has been evaluated. Comparison of manual and automatic batch (36 samples) extraction procedures for tritium labelled prostanoids added as tracers to urine samples has shown equivalent results with recoveries greater than 90% for prostaglandins E2, F2alpha and 6-keto prostaglandin F1alpha as well as thromboxane B2. Analyte stability is not affected by the automated procedure, which uses less solvents and has a faster overall processing time than the manual method. The automated system has been applied to the extraction of prostanoids in urine samples from workers exposed to dichloroethane.

Arachidonic Acids

Influence of N-phenyllinoleamide from toxic oil samples on the lipoxygenase metabolism of exogenous arachidonic acid in mouse peritoneal macrophages.

N-phenyllinoleamide (NPLA) is a useful marker for adulterated oil samples associated with cases of toxic oil syndrome (TOS). To date, NPLA has not reproduced the human poisoning episode in experimental animal models and, thus, its pathological role in the syndrome remains controversial. The present report describes the effect of NPLA on the lipoxygenase metabolism of exogenous arachidonic acid (AA) in mouse peritoneal macrophages (MPM). Results show that MPM cells exposed to 1mM NPLA for 2 h, when subsequently incubated with exogenous 3H-AA, undergo a significant increase in the biosynthesis of 3H-12-hydroxyeicosatetraenoic acid (3H-12-HETE) whereas levels of 3H-15-HETE are relatively stable. These data indicate that NPLA selectively potentiates the lipoxygenase metabolism of exogenous AA, supporting the possible implication of lipid peroxidative processes in the ethiopathology of TOS, although the relatively high NPLA concentration required 'in vitro' makes it unlikely that this xenobiotic could be directly related to human toxicity.

12-Hydroxy-5,8,10,14-eicosatetraenoic Acid

Cyclooxygenase and lipoxygenase arachidonic acid metabolism by monocytes from human immune deficiency virus-infected drug users.

Prostaglandin E2, thromboxane B2 and leukotriene B4 monocyte production have been determined in human immune deficiency virus (HIV)-infected drug users (n = 36) and healthy subjects (n = 29). Eicosanoids were extracted from the incubates using C18 solid-phase cartridges and determined by radioimmunoassay. An enhanced production of prostaglandin E2 and thromboxane B2 was detected in monocytes from HIV-positive drug users whether or not they had been previously stimulated with zymosan. Concomitant leukotriene B4 increases were not observed. The results reported in this paper indicate that altered cyclooxygenase arachidonic acid metabolism in monocytes from HIV-infected drug users is associated with the severe cellular immunodysfunction characteristic of AIDS. In contrast, leukotriene B4 does not seem to play a role in AIDS-associated immunosuppression.

Acquired Immunodeficiency Syndrome

Multicenter evaluation of efficacy, tolerability and safety of a new first-line antihypertensive drug, isradipine, in a Latin-American population.

Isradipine, a new antihypertensive dihydropyridine calcium antagonist, was evaluated for its efficacy, tolerability, and safety in 91 ambulatory patients who had mild-to-moderate hypertension. The design of the present study included a two-week wash-out period after confirmation of disease, followed by 12 weeks of active treatment with 2.5 mg isradipine twice daily. Patients were switched from other antihypertensive drugs, mainly diuretics and beta-blockers. The dose of isradipine remained virtually unchanged throughout the study and resulted in a mean decrease of 22 mm Hg in systolic blood pressure (SBP) (P less than .00001) and 19 mm Hg in diastolic blood pressure (DBP) (P less than .00001). Heart rate was unchanged (difference of -1 beats/min), as was the mean body weight of the study patients. Isradipine was generally well tolerated. Side effects were few and, when present, tended to diminish and eventually disappear during the treatment period. All of the clinical laboratory parameters tested and electrocardiograph intervals remained unchanged. In conclusion, these results indicate that isradipine is a novel drug which is highly effective and well tolerated in the treatment of mild to moderate hypertension in this group of patients.

Adult

[Early intervention in infants with intrauterine growth retardation: its effects on neuropsychological development].

Forty-eight term infants in a tertiary center in Puerto Rico during 1985-86 were monitored prospectively since birth completing a neuropsychological evaluation using the Mental Developmental Index of Bayley Scales. All infants were free from perinatal complications and chronic diseases by clinical evaluation. 25 infants with intrauterine growth retardation (IUGR) and 23 adequate for gestational age (AGA) infants were evaluated. Fourteen IUGR infants were controls and eleven IUGR infants were intervened. However, all AGA infants were used as controls. Mother-infant relationship at one month was scored and none of intervened infants had poor neuropsychological behavior with normal or near normal MDI values. Other relationships and possible explanations are discussed in the article.

Adult

[Multiple primary pulmonary carcinomas].

Three cases of multiple simultaneous primary lung carcinomas are presented, in which diagnosis was established by post-surgery pathological exam. In all three cases, chest X-ray showed pulmonary masses suggestive or clinical malignancy, and pre-surgery pathological diagnosis or squamous lung carcinoma. During thoracotomy or in the resected segment, a second lesion we confirmed which made resection necessary being this second lesion classified as lung adenocarcinoma.

Adenocarcinoma

[The treatment of chronic stable angina with isradipine. A cooperative Latin American study].

In order to study the efficacy and tolerance of isradipine, a new Ca++ antagonist for the treatment of stable chronic angina, a multicentric cooperative study was carried out in eight Latin American countries (Argentine, Chile, Colombia, Ecuador, Mexico, Peru, Uruguay and Venezuela), which included 169 patients (60% men and 40% women), average age 62.6 +/- 9.7. Patients with more than 4 biweekly anginal crisis were accepted, with one or more of the following inclusion criteria: coronariographic evidence of obstruction greater than 60% in one or more vessels, IAM history, positive scintigraphy and positive effort test. The trial was single-blind, with placebo during the admission phase (2 weeks) and active treatment for 12 weeks. isradipine was administered in increasing doses of 2.5, 5, and 7 mg thrice a day, according to the presence or absence of anginal crisis. It was observed that the average frequency of weekly pains decreased from 8.2 +/- 7 under placebo to 6.3 +/- 7.5 under isradipine at low doses, and to 2.0 +/- 2.0 (p less than 0.001) under maximum doses. TNT intake decreased parallel also in a significant way. At the end of the trial, 37% of patients had become asymptomatic, and angina had reduced to less than two crisis a week in 33%. A clear relation doses-effect was observed. There was no alteration in laboratory exams neither in ECG. Seven patients had complications derived from the evolutional course of disease (2 IAM, 5 unstable angina and one sudden death). Adverse events were relatively frequent and the majority derived from vasodilator effect (tibial oedema 37%, flushing 17%, headache 23%).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult

Phenanthrylalkanoic acids, IV: Syntheses and antiinflammatory activity of 2-, 3-, and 9-phenanthryl- and 9-chloro-3-phenanthryl derivatives of propanoic acid.

The phenanthrylethanols 2a-d were obtained by reduction of the acetyl derivatives 1a-d and converted, through the phenanthrylethyl halides 3a-d and 4b, into the nitriles 5a-d, whose acid hydrolysis afforded the acids of the title, 6a-d. The antiinflammatory activity of these acids was measured on the carrageenin-induced edema and found as 1/3 (6a), 1/43 (6b), 1/5 (6c), and 1/7 (6d) of that of fenbufen.

Animals

Prostaglandin E2 and thromboxane B2 levels in rats subjected to pancreas transplantation.

This work undertakes the study of changes in urinary, plasmatic and tissue levels of Thromboxane B2 (TXB2) as well as in tissue Prostaglandin E2 (PGE2) after pancreas transplantation and the effect of superoxide dismutase (SOD) on these changes. For this purpose, streptozotocine induced diabetic rats were subjected to pancreas transplantation. Experimental groups were classified as follows: Group I: Control; Group II: Animals subjected to 15 min of pancreas arterial flow occlusion followed by reperfusion; Group III: Syngenic pancreas transplantation after 12 hours of organ preservation; Group IV: Same as III, but with additional SOD (13 mg/kg) pretreatment. The results indicate that significant increases of PGE2 and TXB2 levels occur as a consequence of the surgical removal, preservation and implantation of the organ. For TXB2 these increases, immediate in plasma and tissue, are not detected in urine until 24 hours after transplantation of the pancreas. The release of TXB2 and PGE2 was effectively prevented in the SOD treated group supporting the role of oxygen free radicals and lipid peroxidation in the processes of ischemia-reperfusion associated to transplantation of the pancreas.

Animals

Estimation and asymptotic properties of the distribution of time-to-tumour in carcinogenesis experiments.

The problem of the estimation of the cumulative hazard function for time-to-tumour is considered for tumours that are not clinically observable and irreversible. The problem is posed in a compartmental model framework like that of Dewanji and Kalbfleisch (1986). The essential data from a single animal that are considered are: its group, age at death, mode of death (natural or sacrifice), and a list of the tumours present at death. No assumption concerning the lethality of the tumour of interest is required. First an isotonic estimator is proposed for the subsurvival function for time-to-tumour, based on the estimator derived by Gómez and Van Ryzin (1987) for the subdistribution function for time-to-tumour which maintains the asymptotic behaviour, that is, it is consistent and asymptotically normal. Then, the cumulative hazard estimator is defined which is itself monotonically increasing, consistent, and asymptotically normal. The limiting variance is computed and a consistent estimator is given. The observable data are summarized in a 4-variate counting process. The intensity of this process and the corresponding martingales were derived by Gómez and Van Ryzin (1987). The martingale theory can then be applied to obtain the desired results. In particular, the limiting variance is easily achieved. Finally, the proposed methods are illustrated with Berlin, Brodsky, and Clifford data on glomerulosclerosis disease in female RF mice.

Animals

Phenanthrylalkanoic acids, III: Syntheses and biological activities of 4-phenanthryl derivatives.

Reformatsky reactions between 2,3-dihydro-4(1H)-phenanthrenone (5) and ethyl alpha-bromoacetate or propanoate yield several unsaturated esters which, upon aromatization followed by saponification, lead to the 4-phenanthrylacetic (1) and 2-(4-phenanthryl)propanoic (2) acids. The analgesic and anti-inflammatory properties of 1 and 2 were measured and compared with those of Fenbufen.

Animals

Myelomalacia as clinical presentation of acute leukemia.

The case of a 27-year-old man is reported in whom neurological symptoms of obstruction of spinal arteries (myelomalacia) was the initial picture of acute leukemia. A review is given of the literature. There are no other reported cases of this very rare association.

Adult

[Immune response against foot-and-mouth disease virus in cattle: effect of vaccination].

Foot and Mouth Disease Virus (FMDV) is one of the most feared animal virus and vaccination still has to be used in many countries. In previous reports, using a murine model, we studied the cellular basis of immune responses against FMDV and were able to show that they are atypical. In cattle, although complete protection may be attained after only one dose of killed virus vaccine, very little is known about protection against FMDV, except for antibody responses, but practically nothing concerning the cellular basis of their immune response. Moreover, since neutralizing titers do not always correlate with protection, the potency of vaccines in controlled by viral challenge. Our aim is to study cellular immune responses against FMDV, and to search for a correlate to protection. As a first step, 55 virgin cattle from a non endemic area (Patagonia) were divided into three groups: C: non immunized controls; HS: immunized with saponine containing vaccine; and EO: with oil emulsified vaccine. After vaccination, they were carried to an endemic area (Buenos Aires), where they were challenged with live FMDV. Animals were bled immediately before and 7 days after challenge, and their white blood cells and lymphocyte subpopulations were counted. All animals showed a marked neutropenia and eosinophilia, significantly higher in HS than in EO and C groups; both parameters were significantly better in the 2nd assay. Total lymphocyte counts were normal. Lymphocyte subpopulations were assessed by immunofluorescence using monoclonal antibodies: their proportions were normal and did not change during illness in group C. Several factors could have induced the observed eosinophilia and neutropenia: parasites, stress, saponine, others.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals

[Milk of calcium lithiasis. Crystallographic study].

We performed a crystallographic study of two cases of milk of calcium lithiasis. Dust from the specimens were studied by x-ray diffraction and thin layer light microscopy. Analyses of the different morphological types and their layers revealed these to be comprised of wewellite and calcium phosphate, except one with pure wewellite in its core and cortex.

Aged

[Cellular localization, half-life, and secretion of peptide YY].

Tissue and plasma concentration of peptide YY (PYY) were measured by means of a radioimmunoassay (RIA) developed in our laboratory, using a specific PYY antiserum generated in New Zealand white rabbits against synthetic PYY, and dextran-coated charcoal to terminate the assay. Cellular localization of PYY was studied immunohistochemically using the peroxidase-antiperoxidase (PAP) technique. The highest tissue concentration of PYY was found in the mucosa of the terminal ileum and colon. PYY-containing secretory granules were primarily found in the basal pole of open-type endocrine cells. Basal plasma concentration of PYY was 70 +/- 9 pg/ml and rose to 357 +/- 30 pg/ml during the IV administration of PYY at 400 pmol/kg-h. A significant correlation was found (r = 0.94, p less than 0.05) between dose of PYY (12.5, 25, 50, 100, 200, 400 pmol/kg-h, IV) and plasma concentration of PYY. The calculated half-life of PYY in plasma was 8.3 +/- 1.9 minutes. Plasma concentration of PYY during the intraduodenal administration of sodium oleate (150 +/- 20 pg/ml) or long-chain triglyceride (187 +/- 37 pg/ml) was similar to plasma concentration of PYY obtained during the IV administration of PYY at 100 pmol/kg-h. Plasma concentration of PYY raised (126 +/- 10 pg/ml) after the administration of bombesin (400 pmol/kg-h, IV). Bile enhanced release of PYY. The present study suggests a hormonal role for PYY.

Amino Acids

Frequency of gallbladder cancer in Chile, a high-risk area.

We report an autopsy study of gallbladder cancer prevalence in Chile, where the risk of this disease is among the highest reported world-wide. In 14,768 autopsy protocols obtained from 3 university hospitals, 45% of women and 20% of men older than 20 years had gallstone disease (the major known risk factor for gallbladder cancer). The prevalence of gallbladder cancer in Chileans was compared to that found in a Swedish-Czechoslovakian autopsy study previously published. These countries were chosen because of their high frequency of gallstone disease. The comparison was performed by using logistic regression models adjusting for possible differences in the age-sex structure or the true incidence of gallstones in both populations. We found that the most important single risk factor for gallbladder cancer in Chile was gallstone disease, with an estimated effect on the logistic scale meaning that the cancer risk for subjects with gallstones is seven times higher than for those without the disease. Second in importance was the risk for sex, women being 2.8 times higher than for men. The estimated difference in the sex composition and the incidence of gallstones resulted in 17.9% higher odds of cancer in Chile than in Sweden and Czechoslovakia. However, this difference was not significant. This study suggests that the major etiologic factors of gallbladder cancer in Chileans, Swedes and Czechoslovakians are primarily related to gallstone disease.

Adult