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Biomedical subjects

J Otero

Publications and source records attributed to J Otero.

At least 55 records · Page 3Linked to original sources
PubMed1991

Biosynthesis of bacterial glycogen. Mutagenesis of a catalytic site residue of ADP-glucose pyrophosphorylase from Escherichia coli.

Site-directed mutagenesis was used to explore the role of Lys-195 in ADP-glucose pyrophosphorylase from Escherichia coli. This residue, which is conserved in every bacterial and plant source sequenced to date, was originally identified as a potential catalytic site residue by covalent modification studies. Mutation of Lys-195 to glutamine produces an enzyme whose Km for glucose 1-phosphate is 600-fold greater than that measured for the wild-type enzyme. The effect on glucose 1-phosphate is very specific since kinetic constants measured for ATP, Mg2+, and the allosteric activator, fructose 1,6-bisphosphate, are unchanged relative to those measured for the wild-type enzyme. Furthermore, the catalytic rate constant, Kcat, for the glutamine mutant is similar to that of the wild-type enzyme. Taken together, the results suggest a role for Lys-195 in binding of glucose 1-phosphate and exclude its role as a participant in the rate-determining step(s) in the catalytic reaction mechanism. To further study the effect of charge, shape, size, and hydrophobicity of the amino acid residue at position 195, a series of mutants were prepared including arginine, histidine, isoleucine, and glutamic acid. In every case, the kinetic constants measured for ATP, Mg2+, and fructose 1,6-bisphosphate were similar to wild-type constants, reinforcing the notion that this residue is responsible for a highly localized effect at the glucose 1-phosphate-binding site and also suggesting that the protein can accommodate a wide range of substitutions at this position without losing its global folding properties. Thermal stability measurements corroborate this finding. The mutations did, however, produce a range of glucose 1-phosphate Km values from 100- to 10,000-fold greater than wild-type, which indicate that both size and charge properties of lysine are essential for proper binding of glucose 1-phosphate at the catalytic site. AMP binding was also affected by the nature of the mutation at position 195. A model for glucose 1-phosphate, ATP, and AMP binding is presented.

Base Sequence↗
PubMed1991

Two-parameter mobile phase optimization for the simultaneous high-performance liquid chromatographic determination of dopamine, serotonin and related compounds in microdissected rat brain nuclei.

A new high-pressure liquid chromatography method with electrochemical detection is described that allows the simultaneous determination of dopamine, serotonin, 3,4-dihydroxyphenylacetic acid, 3-methoxy-4-hydroxyphenylacetic acid, 5-hydroxytryptophan and 5-hydroxyindoleacetic acid in microdissected nuclei from individual rat brains. No sample pre-treatment steps are required. Resolution and analysis time were optimized by a simple limited optimization procedure, involving two-parameter factorial design.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1990

Conjunctival intraepithelial and invasive squamous cell carcinomas treated with strontium-90.

Twenty-seven patients with malignant epithelial tumors of the conjunctiva were treated between 1967 and 1987. Histological diagnosis was intraepithelial epithelioma in 15 cases (56%) and squamous cell carcinoma in 12 (44%). All patients were treated with a strontium-90 source on cup-shaped applicators of different sizes according to the extension of the tumor. Surface dose ranged from 60 Gy in a single treatment to 140 Gy in 7 fractions, depending on the thickness of the lesion. Fifteen patients were previously untreated, 7 were irradiated after some type of surgical treatment and 5 were treated for recurrence after multiple surgical excisions. Follow-up period ranged from 2 to 15 years. No patient died of his tumor. There were four local recurrences, three of them in patients with intraepithelial carcinoma. Two of the recurrences were salvaged with a new beta-ray treatment and the other two with enucleation. Since 1981, standard policy was to irradiate the entire conjunctiva in patients with diagnosis of intraepithelial epithelioma. Five patients developed cataracts. Considering the high primary control rate and minimal morbidity, strontium irradiation should be considered as a first-choice treatment for conjunctival tumors.

Adult↗
PubMed1990

[The Fuenlabrada study: relationship between anthropometric variables and cardiovascular risk factors].

Anthropometric variables were studied in 2,153 healthy children, 1,115 males and 1,038 females, aged 0 to 18 years, of the Fuenlabrada population, Madrid. Height was measured by an anthropometer and weight by a weighting scale. Tricipital and subscapular skinfold thickness were measured by Holtain caliper. Body mass index (kg/m2) and ponderal index (kg/m3) were calculated from weight and height. In the total population skinfold thickness had the highest correlation with total body fat. But, when only obese children (greater than 95 p) were analyzed, other variables like body mass index and ponderal index had also high correlation. Different fatness trends were observed between sexes, although females always were the fattest. In our population the correlation of skinfold thickness, body mass index and ponderal index with lipids, blood pressure, glycemia and uric acid were significant. Obese children and adolescents had nearly a twofold increase in relative risk of arterial hypertension, hypertriglyceridemia, hyperuricemia and low C-HDL.

Adolescent↗
PubMed1989

Individual risk of abdominal disease in patients with stages I and II supradiaphragmatic Hodgkin's disease. A rule index based on 341 laparotomized patients.

A multivariate analysis of the prognostic factors for clinical Stages I and II supradiaphragmatic Hodgkin's disease was carried out with a logistic regression model in 341 patients. The proportion of patients with positive staging laparotomy was greater in males, in individuals with several sites involved, mixed cellularity (MC) or lymphocyte depletion (LD) histologic types, systemic symptoms, or in patients with lower cervical involvement and higher erythrocyte sedimentation rate (ESR), serum copper, and LDH levels. Histology, presence of systemic symptoms (fever and sweats), and number of involved nodal regions were independent predictors of positive laparotomy. Mediastinal involvement is correlated to a significantly lower risk of positive laparotomy. Based on these observations, the individual risk for each patient of occult abdominal disease has been defined.

Abdominal Neoplasms↗
PubMed1989

Hypoglycemic activity of several seaweed extracts.

The hypoglycemic activity of several seaweed extracts on rabbits was studied. Ethanol extracts of Laminaria ochroleuca, Saccorhiza polyschides and Fucus vesiculosus were administered orally to normal animals and their effects on glycemia and triglyceridemia evaluated. Crude polysaccharides and protein solutions from Himanthalia elongata and Codium tomentosum were also assayed. Polysaccharides and proteins from H. elongata caused a significant reduction in blood glucose 8 h after intravenous administration. A case of 5 mg/kg of crude polysaccharide lowered glycemia about 18% in normal rabbits and by about 50% in alloxan-diabetic animals, while the protein solution lowered glycemia in diabetic rabbits by about 30%.

Animals↗
PubMed1989

[Combined chemotherapy with the FEM protocol in advanced gastric cancer].

Thirty one patients with diagnosis of Gastric Cancer were admitted in this study. Median age was 71 years (range 24-82). Twenty two were male. No one had previous chemotherapy. Functional capacity was 0-1 in 26/31 (60.6%). More common symptoms were: loss of weight 21/31 (75.1%) and abdominal pain in 13/31 (40.3%). Ten patients were Borrmann III and nine Borrmann IV. Twenty one had surgery: 12 palliative gastrectomy and 9 exploratory laparatomy. Twenty three cases were adenocarcinoma and 8 undifferentiated carcinoma. FEM regimen was administered (5 Fluoruracil 600 mg/m2/day 1 and 8, Epidoxorubicin 30 mg/m2/day 1 and Mitomycin 10 mg/m2/day 1). Ten of 24 patients (41.7%) achieved partial remission with a median survival of 10.5 months. Three patients achieved subjective response with a median survival of 6 months. Median survival for the non response was 3 months (range 2-7 months). Survival difference between responders and no responders was statistically significant. Survival among the adjuvent group was 5.7 months (range 2-16 months). One out of three patients survived without evidence of disease at the end of this study. Twenty three patients died and 5 were lost to follow up. Alopecia was the most common secondary effect in 74%, nausea and vomiting in 60% and leukopenia below 3000 x mm3 in 54%. Cardiotoxicity was not documented in any case.

Adult↗
PubMed1989

[The Fuenlabrada study: a familial aggregation of ischemic cardiopathy and cardiovascular risk factors].

UNLABELLED: Familial aggregation of coronary heart disease (CHD) and coronary risk factors (CRF) were evaluated by clinical history in adult relatives of children surveyed for CRF. Population was divided into two groups: Group I included 2,153 children without parental history of CHD. Group II included 266 children of 112 families with parental history of early CHD (before 56 years). In 105 cases the patients were the fathers and in 7 cases the mothers. All the patients were admitted to a coronary care unit. Familial aggregation of CHD was 9.7 times more frequent in paternal families of group II (p less than or equal to 0.0001) than in group I; there was no differences in maternal families. Higher prevalence of hyperlipidaemia, blood pressure hypertension, smoking habits, diabetes and obesity in fathers of group II was observed. Children in group II showed increased levels of C-LDL and decreased levels of C-HDL compared with those of group I. The prevalence of CRF was also significantly higher in children of group II, although in the 33% of the children of group II no CRF was detected. CONCLUSION: a substantial proportion, but not all cases, of familial aggregation of CHD could be explained by known CRF.

Adolescent↗
PubMed1989

[The Fuenlabrada study: arterial pressure in children and adolescents].

Blood pressure was studied in 2,153 healthy children of both sexes, from 0 to 18 years of age; 1,115 were males and 1,038 females. Systolic and diastolic blood pressures were measured in the sitting position by the auscultatory method on the right arm with a mercury sphygmomanometer using an appropriate cuff size. Systolic blood pressure was measured on the first sound and diastolic blood pressure in the fourth phase of Korotkoff. In children younger than 3 years blood pressure was measured in the decubitus supine position using the Doppler technique. There were no significant differences in mean systolic and diastolic blood pressure in both sexes. But the percentage of systolic blood pressure greater than or equal to 130 mmHg was higher in males than females (p less than or equal to 0.01). 8.4% of the total population had systolic blood pressure greater than or equal to 130 mmHg, and 1.3% had diastolic blood pressure greater than or equal to 90 mmHg. The annual increase rates of systolic and diastolic blood pressure were 2.31/0.94 mmHg in males and 2/0.97 mmHg in females. Children with blood pressure greater than or equal to the 95th percentile had a higher prevalence of hypertriglyceridemia and obesity. 54% of the variation in systolic blood pressure was explained by the association of weight, subscapular skinfold, body mass index and C-HDL. 30% of the variation in diastolic blood pressure was explained by the association of weight, obesity index, subscapular skinfold and C-HDL.

Adolescent↗
PubMed1989

[Cardiovascular risk factors in children and adolescents in Fuenlabrada: objectives, features of the population, design, participation, equipment, laboratory technics, and quality control].

Fuenlabrada is at the present time the most industrialized town placed at the south are of Madrid. This population has some peculiar attractive characteristics from the epidemiologic point of view. Perhaps the most important is that the majority of its inhabitants are immigrant from other depressed rural areas of the country, with a low socio-economic and cultural level. The new conditions of life could have changed the life expectation and the causes of morbidity and mortality of this population. Between 1981 and 1984 we have studied the prevalence of cardiovascular risk factors in children and adolescents of its population, the relationships with cardiovascular risk factors and cardiovascular disease of the family and type of lactancy of the newborn. The variables studied were: height, weight, skin fold, blood pressure, lipids, lipoproteins, glycemia, uric acid and tobacco habit. The laboratory technics were standardized with serums of reference. The index of participation in the study of the required population was approximately of 80%.

Adolescent↗
PubMed1983

Radiation therapy in craniopharyngiomas.

Eighteen patients with cranipharyngiomas, who were studied and treated between 1970-1980, are presented. Each patient was treated with surgery and radiotherapy (50-60 Gy). Six patients were treated with radiotherapy because the tumor recurred after surgery. An extensive representation of the clinical symptomatology typical of this tumor was seen. In 3 patients an improvement in visual symptoms was demonstrated; in 11 the headaches and vomiting were controlled after treatment. The 18 treated patients are still alive without evidence of progression of the tumor, after a period of 2 to 12 years. Our experience supports the contention that conservative surgery coupled with radical radiotherapy remains the treatment of choice for the craniopharyngioma.

Adolescent↗
PubMed1983

Intracranial tumors with risk of dissemination in neuroaxis.

The experience of the Radiotherapy Service, Clínica Puerta de Hierro, Madrid (Spain), in the treatment of intracranial tumors with risk of neural axis dissemination is analyzed. In 15 years (1964-1979) 415 primary central nervous system tumors were studied and treated; 67 corresponded to tumors with risk of meningeal dissemination. Clinical dissemination in cerebrospinal fluid was proven in 14 patients. The actuarial survival of 10 years for patients with neural axis dissemination, without prophylactic treatment to the neuroaxis, is 14% with an average survival of 10.5 months. In approximately 20% of meduloblastomas, ependymal and pineal region tumors, meningeal metastases at some distance from the primary tumor can take place. Patients at risk wtih these types of neoplasia must be identified, and an adequate radical therapeutic focus devised, not only for the primary tumor, but also for the risk of dissemination.

Adolescent↗
PubMed1983

[Treatment and prevention of lymph node metastasis of carcinomas of the oral cavity].

From 1964-1977, 242 previously untreated patients with a oral cavity carcinoma were treated in the Service of Radiotherapy in the Clínica Puerta de Hierro of Madrid. The actuarial survival at five years was 52,5% (26 T1, 96 T2, 120 T3). The presence of nodes in the moment of treatment was of great prognostic value. And so the actuarial survival at five years of the N(+) was 31% vs 64% in the No (p less than or equal to 005). Of 161 patients without adenopathies (No), 73 patients were treated with prophylactic irradiation of the neck, and 88 patients were kept under observation without any cervical treatment; ganglionary relapses appeared in the 5,5% of the first group vs 26% in the patients who had no cervical treatment at all (p less than or equal to 001), wich reaffirms the value of prophylactic or elective radiotherapy.

Humans↗
PubMed1981

Endoscopic tissue diagnosis of gastric involvement in the staging of non-Hodgkin's lymphoma.

The results of radiologic and endoscopic examinations and endoscopic biopsies of the stomach and duodenum in the staging of non-Hodgkin's lymphoma (NHL) were assessed in 147 patients. Radiologic results were positive for non-Hodgkin's lymphoma in 36 of 147 patients, with diagnosis of NHL from biopsy specimens of 16 of these 36 patients. Results of endoscopic studies were abnormal in 35 of 147 patients and 20 of these 35 patients also had biopsy specimens positive for NHL. Twenty-four patients (16.3%) had NHL involvement of the gastric and/or duodenal mucosa demonstrated by biopsy material. More than 15% of the patients whose primary tumors were nodal, and 19% of those patients with extranodal involvement also had lymphoma involvement of the stomach and/or duodenum. According to the results of the endoscopic biopsies, 15.1% (10 of 66 patients) had Stages I and II, and 17.2% (14 of 81 patients) had Stages II and IV of non-Hodgkin's lymphoma.

Adolescent↗
PubMed1980

[Medulloblastoma. Report of 13 cases (author's transl)].

Thirteen patients with medulloblastoma were admitted to the Clinica Puerta de Hierro (Department of Radiotherapy) between 1964 and 1977. Two subtypes of medulloblastoma (classical and desmoplastic) with different histologic pattern, age of onset, clinical manifestations and clinical course have been identified. Radical surgery does not increase overal survival. X-ray treatment should be applied according to the following principles: a) the central nervous system should be irradiated; b) dosage on the posterior cranial fossa over 5,000 rad (50 Gy); c) dosage on the neuroaxis under 2,000-3,000 rad (25-30 Gy). Tumor recurrences should be treated in order to obtain a more comfortable life and a prolonged survival. Association of chemotherapy to surgery and radiotherapy have yielded promising results.

Adolescent↗