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Biomedical subjects

R Jimenez

Publications and source records attributed to R Jimenez.

At least 19 recordsLinked to original sources
PubMed1998

Aetiology of ovine footrot in Spain.

Four hundred and sixty strains of obligate anaerobes were isolated from 216 cases of ovine foot rot distributed throughout Spain. The predominant species was Dichelobacter nodosus, which was isolated in 168 cases (77.8 per cent). A higher proportion of the strains of D nodosus than of the other strains had elastolytic activity, 118 of the 168 strains degrading elastin. Species belonging to the genus Prevotella were isolated from 96 cases (44.4 per cent). Serotyping of the D nodosus strains showed that serovars A1, A2 and C were the most commonly isolated in Spain.

Animals↗
PubMed1998

Globular cluster ages.

We review two new methods to determine the age of globular clusters (GCs). These two methods are more accurate than the classical isochrone fitting technique. The first method is based on the morphology of the horizontal branch and is independent of the distance modulus of the globular cluster. The second method uses a careful binning of the stellar luminosity function and determines simultaneously the distance and age of the GC. We find that the oldest galactic GCs have an age of 13.5 +/- 2 gigayears (Gyr). The absolute minimum age for the oldest GCs is 10.5 Gyr (with 99% confidence) and the maximum 16.0 Gyr (with 99% confidence). Therefore, an Einstein-De Sitter Universe (Omega = 1) is not totally ruled out if the Hubble constant is about 65 +/- 10 Km s-1 Mpc-1.

Journal Article↗
PubMed1996

Body cavity-based malignant lymphoma containing Kaposi sarcoma-associated herpesvirus in an HIV-negative man with previous Kaposi sarcoma.

BACKGROUND: The role of Kaposi sarcoma-associated herpesvirus in the development of malignant lymphomas in patients negative for the human immunodeficiency virus (HIV) has not been established. OBJECTIVE: To examine the possible role of Kaposi sarcoma-associated herpesvirus in a case of body cavity-based malignant lymphoma that occurred in an HIV-negative patient who had previously had Kaposi sarcoma. DESIGN: Case study. SETTING: Academic medical center. PATIENT: A 94-year-old man with lymphomatous ascites. MEASUREMENTS: Polymerase chain reaction (PCR) and Southern blot DNA analysis. RESULTS: The body cavity-based lymphoma cells were positive for Kaposi sarcoma-associated herpesvirus by PCR and were negative for other herpesviruses, including Epstein-Barr virus, cytomegalovirus, and human herpesviruses 6 and 7. Southern blot analysis of lymphoma DNA showed high levels of Kaposi sarcoma-associated herpesvirus (> 40 to 80 genomes/cell). Clonal rearrangement of the immunoglobulin JH and JK genes was present, confirming the presence of a clonal B-cell proliferation. CONCLUSIONS: Kaposi sarcoma-associated herpesvirus may be involved in the development of malignant lymphoma after Kaposi sarcoma in HIV-negative patients. This type of lymphoma, in contrast to body cavity-based lymphoma related to the acquired immunodeficiency syndrome, may have an indolent clinical course.

Aged↗
PubMed1995

Inhibition of neutrophil adhesion by adenosine and an adenosine kinase inhibitor. The role of selectins.

Adenosine and adenosine analogues exhibit anti-inflammatory effects in vitro and in vivo, but their usefulness is limited by profound cardiovascular side effects. Therefore, we synthesized inhibitors of an enzyme involved in adenosine metabolism, adenosine kinase (AK) (EC 2.7.1.20), to enhance endogenous adenosine concentrations at sites of inflammation. GP-1-515 (4-amino-1-(5-amino-5-deoxy-1-beta-D- ribofuranosyl)-3-bromo-pyrazolo[3,4-d]pyrimidine), a novel AK inhibitor, decreased adhesion of activated human neutrophils to cultured endothelial cell monolayers by increasing local adenosine levels. The mechanism of inhibition in this assay seemed to involve selectin blockade and was independent of the beta 2 integrins. GP-1-515 and 2-chloroadenosine (a nonmetabolizable adenosine analogue) had no effect on the surface expression or shedding of adhesion molecules. An agent that disrupts the cytoskeleton, cytochalasin B, mimicked the effect of adenosine on cell adhesion. Interactions between L-selectin and the neutrophil cytoskeleton might be altered by adenosine and could contribute to adenosine-mediated adhesion inhibition.

2-Chloroadenosine↗
PubMed1995

Influence of vitamin C on the absorption and first pass metabolism of propranolol.

The effect of ascorbic acid on the availability of propranolol has been examined. After oral administration of propranolol 80 mg with or without ascorbic acid pretreatment (2 g), the plasma concentrations and urinary excretion of propranolol and its metabolites, 4-hydroxy-propranolol and propranolol-conjugated, were determined by HPLC. Compared to controls, vitamin C decreased the maximum concentration of propranolol from 463 to 334 nmol.l-1, and the area under the propranolol concentration-time curve (from 0 to 24 hours) from 3.13 to 1.96 mumol.l-1.h. The time to reach maximum propranolol concentration was increased from 1.9 to 2.7. The total amount of drug recovered in urine has also significantly diminished (from 12.6 to 4.29 mg). No change in elimination rate was observed, indicating that ascorbic acid had affected both the absorption process and the first pass metabolism. The heart-rate decreased less when propranolol was administered with ascorbic acid in comparison to control subjects, although this interaction has little biological importance.

Administration, Oral↗
PubMed1995

X-linked familial exudative vitreoretinopathy. Report of one family.

BACKGROUND: Familial exudative vitreoretinopathy is an uncommon heredodegenerative disease with different types of inheritance and degrees of severity. METHODS: Findings in five affected members of a family in which the X-linked mode of inheritance of familial exudative vitreoretinopathy is present are discussed. RESULTS: Patients presented with characteristic retinal exudative tractional detachment, temporal retinal vessel traction, capillary dilatation, neovascularization, and vitreous veils. CONCLUSION: A review of the 21 cases of X-linked familial exudative vitreoretinopathy reported to date indicates a worse outcome in this mode of inheritance than in cases of autosomal dominant inheritance.

Adolescent↗
PubMed1993

Effect of the quality of infused energy on substrate utilization in the newborn receiving total parenteral nutrition.

Newborn infants (n = 26), subdivided into three groups in which only the nonprotein energy was manipulated, were studied during continuously administered total parenteral nutrition. Nonprotein energy intake was provided as a glucose/fat mixture, and fat energy represented 18% (group A), 29% (group B), and 40% (group C). Energy expenditure and substrate utilization were measured by indirect calorimetry during a 6-h period. Other analyses included 24-h urinary nitrogen excretion, glycemia, and lipid profile. The results showed that glucose oxidation increased with increasing total glucose intake (p < 0.05). Net fat oxidation was observed in all groups and increased with increasing percentage of energy infused as fat. The maximal oxidative glucose disposal rate observed was in group A (11.2 g/kg/d). Maximal fat oxidation observed was in group C (2 g/kg/d), in which energy delivered by fat represented 40%. This group was more energy efficient than the others. Oxygen consumption was not affected by modification of the source of energy, but carbon dioxide production was higher in group A (p < 0.05), as was the nonprotein respiratory quotient (p < 0.05). Despite differences in carbon dioxide production, arterial capillary PCO2 was not affected and, together with the higher (p < 0.05) minute ventilation, suggests that adequate pulmonary compensation occurred during the low-fat regimen. Arterial capillary PO2 was lower during the high-fat regimen (p < 0.05). Protein oxidation was greater in group A (1.14 +/- 0.32 g/kg/d) than in group B (0.70 +/- 0.21 g/kg/d) or group C (0.78 +/- 0.28 g/kg/d).(ABSTRACT TRUNCATED AT 250 WORDS)

Dietary Carbohydrates↗
PubMed1993

Effects of a hypercholesterolaemia-inducing diet on biliary electrolytes and lipid secretion in the rat.

The effects of a high cholesterol/cholate diet on the biliary secretion of bile acids, cholesterol, phospholipid and inorganic electrolytes in the rat were examined. Wistar rats were fed a hypercholesterolaemia-inducing diet (HID) for 20 days prior to the biliary experiments. Rats fed a standard laboratory diet were used as controls. The HID diet increased plasma cholesterol concentrations and the hepatic content of total, free and esterified cholesterol, without changes in ALP*, ALT and AST plasma activities. Bile flow and biliary secretion of bile acids and inorganic electrolytes were markedly increased in the hypercholesterolaemic animals. The stimulated biliary secretion was due to an increase in both the bile acid-dependent and bile acid-independent fractions of bile flow. An increase in the bile acid pool induced by the administration of exogenous cholic acid/cholesterol would account for these changes in bile flow and inorganic electrolyte secretion. Nevertheless, the increase in the bile acid-independent bile flow could be also related, at least to some extent, to a higher efficiency of bicarbonate transport into bile. The HID diet also increased both cholesterol and phospholipid biliary outputs, whereas it did not modify the relationship between lipid and bile acid secretion. The lithogenic index of bile was reduced in the rats after the HID regimen due to a relatively higher increase in the biliary outputs of phospholipids and bile acids than of cholesterol.

Animals↗
PubMed1993

Atrial natriuretic factor in neonatal hypoxic-ischemic encephalopathy.

The influence of perinatal asphyxia in the secretion of atrial natriuretic factor (ANF) during the first 6 days of life, and its renal consequences are discussed. Comparison between 20 healthy term neonates and 19 with first--or second--degree hypoxic-ischemic encephalopathy (HIE) is made. Daily controls were performed on clinical and neurological examinations and administration of sodium and fluids. On the first and sixth days of life, 24 hours urine collection, natremia, natriuresis, fractionated excretion of sodium and creatinine clearance were determined. The ANF was performed at 1, 2, 3 and 6 days old, by R.I.A. The full term newborns with HIE showed a peak in ANF values on day two, as does the control group, thereafter maintaining higher levels, with a significant difference on day three and six. No correlation could be found between the ANF levels and the renal variables analyzed.

Asphyxia Neonatorum↗
PubMed1992

Inhibition of biliary lipid and protein secretion by cyclosporine A in the rat.

We investigated the effect of cyclosporine A (CyA) administered as a single i.v. dose of 20 and 40 mg/kg body wt, on biliary secretion of cholesterol, phospholipid, bile acid, and lysosomal marker and canalicular plasma membrane marker enzymes in anaesthetized Wistar rats. CyA reduced the concentration and biliary secretion of cholesterol, phospholipid and bile acid to a considerable extent; the inhibitory effect of CyA on the biliary secretion of phospholipid and bile acid was greater than that on cholesterol. The biliary outputs of acid phosphatase (AcP) and gamma-glutamyltransferase (gamma-GT) were also diminished by the drug, all these effects being dose-dependent. Maximum decreases in bile acid secretion were observed 10 min after administration, whereas those of cholesterol and phospholipid were delayed. Bile acid concentrations and secretion returned to pretest values at 30-50 min after CyA injection whereas those of cholesterol and phospholipid remained significantly reduced at this time point. The greater inhibitory effect of CyA on the biliary outputs of phospholipid and bile acid relative to cholesterol secretion together with the asynchronous fall and recovery of bile acid, cholesterol and phospholipid concentrations and secretion alter the cholesterol/bile acid, phospholipid/bile acid and cholesterol/phospholipid molar ratios as well as the lithogenic index, thus suggesting that CyA would uncouple biliary lipid secretion from bile acid secretion. Since under physiological conditions biliary lipid and gamma-GT secretion is related to and dependent upon bile acid secretion, we propose that the CyA-induced inhibition on lipid and gamma-GT secretion is, at least partly, secondary to the fall in bile acid output caused by the drug. However, since CyA inhibits secretory processes independent of the hepatobiliary flux of bile acid, such as the exocytic discharge of AcP, and because it also uncouples biliary lipid from bile acid secretion, other mechanisms and factors involved in lipid and protein secretion (such as intracellular transport, canalicular membrane fluidity and/or intracanalicular events) might also be altered by this drug.

Animals↗
PubMed1992

Increased expression of natural-killer-associated and activation antigens in multiple myeloma.

The expression of both natural-killer (NK)-associated and activation antigens was studied by flow cytometry in the peripheral blood of 47 untreated multiple myeloma (MM) patients. A significant increase in both absolute and relative numbers of CD57 positive cells as well as in the proportion of CD16 and CD11b cells was observed in patients with MM, specially in those in early stages of the disease (clinical stages I and II), suggesting a possible surveillance mechanism in response to an emerging malignant clone. Additional double stainings showed that strong CD16+ NK cells coexpress the CD56, CD11b, and CD2 antigens, while they lacked CD3, CD5, and WT31 antigens. Moreover, the previously reported increase in CD8 cells present in MM would be mainly due to a subset of CD8 cells that coexpress the CD57 Ags. The expression of activation antigens, especially CD38, was increased in peripheral blood lymphocytes of MM patients, the differences reaching statistical significance both in absolute and relative numbers in those cases with high numbers of CD16 NK cells and thus suggesting that these cells are functionally activated. These results reveal the existence of an increase in NK and activated cells in the peripheral blood of myeloma patients that may reflect a host's immunological mechanism in an attempt to modulate tumor cell growth.

ADP-ribosyl Cyclase↗
PubMed1992

[Tamoxifen as the primary treatment for breast cancer in elderly patients].

A total of 21 elderly patients with breast carcinoma without evidence of systemic dissemination received tamoxifen (20 mg daily) as primary treatment. Of these 57% had a potentially operable tumor (stages I:2, IIa:6, IIb:2, IIIa:2) with a high operative risk that contraindicated the surgery and 43% had a locally advanced tumor unfit for primary radiotherapy, chemotherapy, or surgery. The mean age was 81.3 +/- 5.7 years (range 70-91). Diagnosis was made by fine-needle aspiration cytology in 16 patients and by incision biopsy in 5 of them. The median follow-up was 11.5 months (range 3-54). In 67% there was a clinical objective response (RC: 14%, RP: 53%), and 33% had disease stabilization. There was no evidence of systemic dissemination during the follow-up. Two patients who had achieved a partial response with a duration of 11 and 54 months, respectively, had a loco regional progress. One of them responded to a second hormonal treatment. Of the patients, 81% are still alive, and 14% died of other causes. One patient was lost during the follow-up. These preliminary results show a high loco regional response to tamoxifen. A higher number of patients and a longer time of follow-up are needed to establish the habitual use of tamoxifen as primary treatment of breast carcinoma in elderly patients.

Aged↗
PubMed1991

Inhibition of biliary cholesterol and phospholipid secretion by cefmetazole. The role of vesicular transport and of canalicular events.

A number of organic anions selectively inhibit the biliary secretion of cholesterol and phospholipids without affecting bile acid secretion. We studied the effect of cefmetazole, a third-generation cephalosporin, on biliary lipid secretion in the rat. Injection of cefmetazole at a dose of 200 mumol/kg body wt. induced a choleretic effect and a significant decrease in the biliary output of cholesterol and phospholipid, without changes in bile acid secretion. The decrease was more marked for cholesterol than for phospholipid secretion, with a significant decrease in their molar ratio in bile. The effects were apparently unrelated to an inhibition of intracellular vesicular transport because, after injection of horseradish peroxidase, both the time course and total amount secreted of the protein did not significantly differ between control animals and those receiving cefmetazole. The secretory rate of the lysosomal marker acid phosphatase was not affected by cefmetazole administration. Biliary outputs of the plasma-membrane enzymes alkaline phosphatase and gamma-glutamyltransferase were significantly decreased by the antibiotic. These results point to an effect of cefmetazole at the level of the canalicular membrane.

Alkaline Phosphatase↗
PubMed1991

Immunophenotypic heterogeneity of multiple myeloma: influence on the biology and clinical course of the disease. Castellano-Leones (Spain) Cooperative Group for the Study of Monoclonal Gammopathies.

In 112 untreated myeloma patients we have analysed the immunophenotype of plasma cells both by immunofluorescence (IF) and immunocytochemistry (APAAP). Both techniques yielded similar results pointing to an important degree of heterogeneity in antigenic expression not only between different patients but also within the same patient. The expression of CD38 and Han-PC1 antigens (Ags) was almost constant (greater than 90% positive cases), while CD9 was detected in 66% of the cases. On the other hand, less than one third of patients were positive for CD10, CD20 and HLA-DR and generally with a weak expression (less than 30% positive plasma cells). In occasional cases plasma cells were weakly positive for the myelomonocytic markers CD13 (9%), CD15 (25%) and CD14 (6%). The possibility that this heterogeneity might be the result of different stages of differentiation of the neoplastic clone is suggested both by the positive correlation in the expression of some of these antigens (CD10, CD9, CD20, HLA-DR) and by the relationship between CD10 and myeloid antigens with immature plasma cell morphology. Finally, the cALLA antigen does not seem to be of significant value in predicting survival. Moreover, none of the other markers explored showed a clear influence in the course of the disease, although the tendency towards a lower survival found for the CD20+ cases as well as the association of the expression of some antigens and advanced clinical stage, may warrant further studies in a larger series of patients.

Aged↗