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Biomedical subjects

M Bosch

Publications and source records attributed to M Bosch.

At least 37 records · Page 2Linked to original sources
PubMed2001

Induction of potent human immunodeficiency virus type 1-specific T-cell-restricted immunity by genetically modified dendritic cells.

A novel technology combining replication- and integration-defective human immunodeficiency virus type 1 (HIV-1) vectors with genetically modified dendritic cells was developed in order to induce T-cell immunity. We introduced the vector into dendritic cells as a plasmid DNA using polyethylenimine as the gene delivery system, thereby circumventing the problem of obtaining viral vector expression in the absence of integration. Genetically modified dendritic cells (GMDC) presented viral epitopes efficiently, secreted interleukin 12, and primed both CD4(+) and CD8(+) HIV-specific T cells capable of producing gamma interferon and exerting potent HIV-1-specific cytotoxicity in vitro. In nonhuman primates, subcutaneously injected GMDC migrated into the draining lymph node at an unprecedentedly high rate and expressed the plasmid DNA. The animals presented a vigorous HIV-specific effector cytotoxic-T-lymphocyte (CTL) response as early as 3 weeks after a single immunization, which later developed into a memory CTL response. Interestingly, antibodies did not accompany these CTL responses, indicating that GMDC can induce a pure Th1 type of immune response. Successful induction of a broad and long-lasting HIV-specific cellular immunity is expected to control virus replication in infected individuals.

Animals↗
PubMed2001

Calmodulin binds to K-Ras, but not to H- or N-Ras, and modulates its downstream signaling.

Activation of Ras induces a variety of cellular responses depending on the specific effector activated and the intensity and amplitude of this activation. We have previously shown that calmodulin is an essential molecule in the down-regulation of the Ras/Raf/MEK/extracellularly regulated kinase (ERK) pathway in cultured fibroblasts and that this is due at least in part to an inhibitory effect of calmodulin on Ras activation. Here we show that inhibition of calmodulin synergizes with diverse stimuli (epidermal growth factor, platelet-derived growth factor, bombesin, or fetal bovine serum) to induce ERK activation. Moreover, even in the absence of any added stimuli, activation of Ras by calmodulin inhibition was observed. To identify the calmodulin-binding protein involved in this process, calmodulin affinity chromatography was performed. We show that Ras and Raf from cellular lysates were able to bind to calmodulin. Furthermore, Ras binding to calmodulin was favored in lysates with large amounts of GTP-bound Ras, and it was Raf independent. Interestingly, only one of the Ras isoforms, K-RasB, was able to bind to calmodulin. Furthermore, calmodulin inhibition preferentially activated K-Ras. Interaction between calmodulin and K-RasB is direct and is inhibited by the calmodulin kinase II calmodulin-binding domain. Thus, GTP-bound K-RasB is a calmodulin-binding protein, and we suggest that this binding may be a key element in the modulation of Ras signaling.

3T3 Cells↗
PubMed2000

Cationic and neutral diphenyldiazomethanerhodium(I) complexes as catalytically active species in the C-C coupling reaction of olefins and diphenyldiazomethane

Cationic rhodium(I) complexes cis-[Rh(acetone)2(L)(L')]+ (2: L = L'=C8H14; 3: L=C8H14; L'=PiPr3; 4: L=L'=PiPr3), prepared from [RhCl(C8H14)2]2] and isolated as PF6 salts, catalyze the C-C coupling reaction of diphenyldiazomethane with ethene, propene, and styrene. In most cases, a mixture of isomeric olefins and cyclopropanes were obtained which are formally built up by one equivalent of RCH=CH2 (R = H, Me, Ph) and one equivalent of CPh2. The efficiency and selectivity of the catalyst depends significantly on the coordination sphere around the rhodium(I) center. Treatment of 4 with Ph2CN2 in the molar ratio of 1:1 and 1:2 gave the complexes trans-[Rh(PiPr3)2(acetone)(eta1-N2CPh2)]PF6 (8) and trans-[Rh(PiPr3)2(eta1-N2CPh2)2]PF6 (9), of which 8 was characterized by X-ray crystallography. Since 8 and 9 not only react with ethene but also catalyze the reaction of C2H4 and free Ph2CN2, they can be regarded as intermediates (possibly resting states) in the C-C coupling process. The lability of 8 and 9 is illustrated by the reactions with pyridine and NaX (X=Cl, Br, I, N3) which afford the mono(diphenyldiazomethane)rhodium(I) compounds trans-[Rh(PiPr3)2(py)(eta1-N2CPh2)]PF6 (10) and trans-[RhX(eta1-N2CPh2)(PiPr3)2] (11-14), respectively. The catalytic activity of the neutral complexes 11 - 14 is somewhat less than that of the cationic species 8, 9 and decreases in the order Cl > Br> I > N3.

Journal Article↗
PubMed2000

Relationship of abdominal adiposity and dyslipemic status in women with a common mutation in the lipoprotein lipase gene. The REGICOR investigators.

Abdominal obesity constitutes an important risk factor for cardiovascular disease. Hypertriglyceridemia and low high-density lipoprotein (HDL) cholesterol concentration constitute the major lipid alterations observed in obesity. A common variant of the lipoprotein lipase (LPL) gene, the HindIII polymorphism, has been found to be associated with changes in triglyceride and HDL-cholesterol levels. We have investigated the impact of the LPL HindIII polymorphism on the relationship between abdominal adiposity and lipoprotein concentrations in 156 randomly selected women in a cross-sectional study conducted in the province of Gerona, in the northeast of Spain. The waist-to-hip ratio was used as an estimate of regional fat distribution. Serum lipid and lipoprotein measurements as well as lipoprotein lipase-HindIII genotypes were determined. Percentile 50 of waist-to-hip ratio (WHR) (0.81) was used as a cutoff to define low or high WHR groups, which significantly differed in blood pressure and lipid trait concentrations. Serum triglyceride concentrations and mean log triglyceride-to-HDL-cholesterol ratio were significantly higher in H+ homozygous women compared with H- carriers. Whereas no statistically-significant differences were observed in HDL-cholesterol concentration and log triglyceride-to-HDL-cholesterol ratio of H- carriers between WHR groups, H+ homozygous women showed significant differences in these lipid traits. It is noteworthy that high-WHR H- carrier women showed a mean HDL-cholesterol value similar to those of both genotypes in the low WHR group. A statistically significant interaction between WHR and genotype was observed for HDL-cholesterol concentration (P=0. 027) and log triglyceride-to-HDL-cholesterol ratio (P=0.040). These results stress the compensating effects that weight loss may have on women with adverse genetic factors. From a complementary viewpoint, the presence of the H- allele seems to confer a protective lipid profile, even when an adverse anthropometric factor such as abdominal adiposity is present.

Abdomen↗
PubMed2000

The measurement of exhaled carbon monoxide is influenced by airflow obstruction.

The concentration of carboxyhaemoglobin (COHb) is often estimated from measurements of carbon monoxide in the exhaled air (COexh). This study investigates whether the presence of airflow obstruction significantly alters the relationship between COexh and COHb. Eighty-one regular smokers were prospectively studied and divided in four groups according to the presence and severity of airflow obstruction (none, mild, moderate, severe). In each subject, the authors measured in this order: 1) arterial blood gases; 2) haemoglobin concentration and COHb (by co-oxymetry); 3) COexh; 4) lung volumes; and 5) forced spirometry. The size of the measurement error (deltaCO) was calculated from the difference between COHb and COexh. Neither the smoking history nor COexh were different in the four groups of subjects studied. In contrast, deltaCO increased in parallel to the degree of airflow obstruction. DeltaCO was >2% (a threshold value normally used in the clinic to separate smokers from nonsmokers) only in patients with severe airflow obstruction. A stepwise multivariate analysis showed that both forced expiratory volume in one second (FEV1) (percentage reference) and COHb contributed significantly (p<0.0001) to predict deltaCO. This study shows that the estimation of carboxyhaemoglobin from exhaled carbon monoxide measurements can be inaccurate in patients with severe airflow obstruction. In these patients, the direct measurement of carboxyhaemoglobin seems advisable in clinical practice.

Adult↗
PubMed1999

Production of engineered human pancreatic ribonucleases, solving expression and purification problems, and enhancing thermostability.

Human pancreatic ribonuclease, the homolog of bovine pancreatic ribonuclease, has a significant therapeutic potential. Its study has been hindered by the difficulty of obtaining the enzyme in a pure and homogeneous form, either from human source or using heterologous expression. Engineering of different variants of human pancreatic ribonuclease has allowed us to study and overcome some problems encountered during its heterologous production in an Escherichia coli system and its purification from inclusion bodies. The 5'-end region of the mRNA that encodes the enzyme is critical for obtaining high expression levels. The results also suggest the importance of the proline 50 residue in the recovery yields of human pancreatic ribonuclease. All the variants produced are pure and homogeneous. Their homogeneity has been demonstrated by cation-exchange and reversed-phase chromatography and by mass spectrometry analysis. Moreover, enhancement of human pancreatic ribonuclease thermal stability is observed when residues R4, K6, Q9, D16, and S17 are changed to the corresponding residues of bovine seminal ribonuclease.

Amino Acid Sequence↗
PubMed1999

Analysis of sex chromosome aneuploidy in sperm from fathers of Turner syndrome patients.

Numerical sex chromosome abnormalities were analyzed in sperm from four fathers of Turner syndrome patients of paternal origin to determine whether there was an increased frequency of sex chromosome aneuploidy and to elucidate whether meiotic malsegregation mechanisms could be involved in the origin of Turner syndrome. Determination of the parental origin of the single X chromosome (maternal in all four cases) and exclusion of X and Y mosaicism were carried out by polymerase chain reaction amplification of five X chromosome polymorphisms and three Y chromosome segments. A total of 45,299 sperm nuclei from Turner fathers and 85,423 sperm nuclei from eight control donors was analyzed by three-color fluorescence in situ hybridization. The four patients showed a significant increase in the percentages of XY sperm (mean 0.22%; range 0.20% to 0.22%) compared with control donors (mean 0.11%; range 0.06% to 0.18%). These results suggest that the four individuals have an increased frequency of nondisjunctional errors in meiosis I, resulting in the production of an increased proportion of XY spermatozoa and of sperm lacking a sex chromosome.

Adult↗
PubMed1999

[The results of the operation of a monitoring unit for home oxygen therapy].

OBJECTIVE: This study aims to a) analyze the prevalence of domiciliary oxygen therapy (DOT) in Mallorca, b) evaluate the cost effectiveness of the DOT monitoring unit, and c) determine the survival of patients with chronic obstructive pulmonary disease who are presently receiving DOT. METHOD: When the DOT unit was created in April 1994, the situation of all patients receiving DOT in Mallorca was assessed in a transversal study. Over the next three years, these patients were reassessed regularly and all new prescriptions were evaluated (longitudinal study). RESULTS: Before the unit began work, DOT was prescribed for 71 out of 100,000 inhabitants. DOT was withdrawn from 31% of patients assessed in the transversal study. By the end of the longitudinal study, DOT was being prescribed at a rate of 56 times per 10,000 inhabitants. The activities of the DOT unit brought about annual savings of approximately 38 million pesetas. The number of patients with liquid oxygen and concentrators increased such that the latter has become the main delivery system. The survival of COPD patients with DOT in this study seems to be longer than report. CONCLUSIONS: a) The prevalence of DOT use in Mallorca before the DOT unit began operating was too high. b) The cost effectiveness of DOT monitoring is positive because DOT use has been optimized and significant savings have ensued (= 38 millions pesetas/year). c) The survival of COPD patients receiving DOT at present appears better than that reported in the literature, possibly related to the greater efficacy of modern treatment.

Aged↗
PubMed1999

Serial measurements of exhaled nitric oxide during exacerbations of chronic obstructive pulmonary disease.

Excessive inflammation seems important in chronic obstructive pulmonary disease (COPD), particularly during exacerbations of the disease. Exhaled nitric oxide concentration ([NOexh]) is a sensitive marker of bronchial inflammation in asthma; it is unclear if this is also the case in COPD. This study: 1) quantifies [NOexh] in patients with COPD (during an exacerbation and while clinically stable); 2) investigates the response of [NOexh] to i.v. steroid therapy, and its potential relationship with other relevant physiological variables; and 3) assesses the relative contributions of the central and peripheral airways to [NOexh] by collecting exhaled air in two different bags connected in series. Seventeen COPD patients (forced expiratory volume in one second (FEV1) 37.6+/-3.4% of the predicted value (+/-SEM)) hospitalized because of an exacerbation of the disease (arterial oxygen tension (Pa,O2) (7.46+/-0.72 kPa 56.1+/-5.4 mmHg), arterial carbon dioxide tension (Pa,CO2) 5.63+/-0.37 kPa 42.3+/-2.8 mmHg), pH 7.41+/-0.02) and 10 healthy subjects that served as controls were studied. On admission, [NOexh] in COPD was higher than normal (41.0+/-5.1 versus 13.3+/-0.8 parts per billion (ppb), respectively, p<0.001). Despite i.v. steroid therapy, [NOexh] remained elevated throughout recovery (37.9+/-4.8 ppb, p<0.001) until discharge (40.9+/-4.3 ppb, p<0.001). In contrast, when the patients were clinically stable (several months later), [NOexh] was significantly reduced (15.8+/-3.8 ppb, p<0.001), and no longer different from control values. [NOexh] was not related to any of the physiological variables measured during recovery (pulmonary gas exchange) or at discharge (forced spirometry, lung volumes, diffusing capacity). Finally, the contribution of the central and peripheral airways to [NOexh] was not different at any point in time. These results indicate that during exacerbations of chronic obstructive pulmonary disease, the exhaled nitric oxide concentration: 1) is higher than normal; 2) is not reduced acutely by i.v. steroids but is normalized several months after discharge; 3) is unrelated to several physiological indices of disease severity; and 4) appears to be produced homogeneously in central and peripheral airways. Overall, these results are different from those reported in asthma, suggesting that different inflammatory mechanisms are operating in both diseases.

Aged↗
PubMed1999

Secretory immunoglobulin A is a component of the human milk fat globule membrane.

Secretory immunoglobulin A (sIgA), the predominant antibody fraction of human milk, represents a major protective factor against neonatal infection. Until now, sIgA had been identified only in the humoral fraction of human milk. The aim of this study was to assess whether in human milk sIgA is also associated with the milk fat globule (MFG). Using anti-sIgA-agglutinated human MFG and immune fluorescence microscopy, we could demonstrate that sIgA is, in fact, associated with human MFG. In human MFG membranes separated by Western blotting, sIgA bands were specifically stained, suggesting that sIgA is strongly associated with the human MFG membrane. This may be of physiologic relevance, inasmuch as earlier we could show that a quantity of undigested and functional human MFG are in fact found in the stools of the newborn. This would allow an additional extension of the protective mechanisms of sIgA throughout the whole intestine.

Agglutination Tests↗
PubMed1999

N-Ras induces alterations in Golgi complex architecture and in constitutive protein transport.

Aberrant glycosylation of proteins and lipids is a common feature of many tumor cell types, and is often accompanied by alterations in membrane traffic and an anomalous localization of Golgi-resident proteins and glycans. These observations suggest that the Golgi complex is a key organelle for at least some of the functional changes associated with malignant transformation. To gain insight into this possibility, we have analyzed changes in the structure and function of the Golgi complex induced by the conditional expression of the transforming N-Ras(K61) mutant in the NRK cell line. A remarkable and specific effect associated with this N-Ras-induced transformation was a conspicuous rearrangement of the Golgi complex into a collapsed morphology. Ultrastructural and stereological analyses demonstrated that the Golgi complex was extensively fragmented. The collapse of the Golgi complex was also accompanied by a disruption of the actin cytoskeleton. Functionally, N-Ras-transformed KT8 cells showed an increase in the constitutive protein transport from the trans-Golgi network to the cell surface, and did not induce the appearance of aberrant cell surface glycans. The Golgi complex collapse, the actin disassembly, and the increased constitutive secretion were all partially inhibited by the phospholipase A2 inhibitor 4-bromophenylacyl bromide. The results thus suggest the involvement of the actin cytoskeleton in the shape of the Golgi complex, and intracellular phospholipase A2 in its architecture and secretory function.

Acetophenones↗
PubMed1999

Effects of local density on pollination and reproduction in Delphinium nuttallianum and Aconitum columbianum (Ranunculaceae).

Plant populations vary in density both naturally and as a consequence of anthropogenic impacts. Density in turn can influence pollination by animals. For example, plants in dense populations might enjoy more frequent visitation if pollinators forage most efficiently in such populations. We explored effects of plant density on pollination and seed set in the larkspur Delphinium nuttallianum and monkshood Aconitum columbianum. At our site in the Colorado Rocky Mountains, flowers of D. nuttallianum are pollinated primarily by queen bumble bees, solitary bees, and hummingbirds, whereas those of A. columbianum are pollinated primarily by queen and worker bumble bees. We found that the quantity of pollination service to both species (pollinator visitation rate and pollen deposition) was at best weakly related to density. In contrast, seed set declined by approximately one-third in sparse populations relative to nearby dense populations. This decline may stem from the receipt of low-quality pollen, for example, inbred pollen. Alternatively, sparsity may indicate poor environmental conditions that lower seed set for reasons unrelated to pollination. Our results demonstrate the value of simultaneously exploring pollinator behavior, pollen receipt, and seed set in attempting to understand how the population context influences plant reproductive success.

Journal Article↗
PubMed1998

Calmodulin inhibitor W13 induces sustained activation of ERK2 and expression of p21(cip1).

One of the major signaling pathways by which extracellular signals induce cell proliferation and differentiation involves the activation of extracellular signal-regulated kinases (ERKs). Because calmodulin is essential for quiescent cells to enter cell cycle, the role of calmodulin on ERK2 activation was studied in cultured fibroblasts. Serum, phorbol esters, or active Ras induced ERK2 activation in NIH 3T3 fibroblasts. This activation was not inhibited by calmodulin blockade. Surprisingly, inhibition of calmodulin prior to fetal bovine serum addition prolonged activation of ERK2. Furthermore, inactivation of calmodulin in serum-starved cells induced ERK2 phosphorylation that was dependent on MAP kinase kinase (MEK). Inactivation of calmodulin in serum-starved cells also induced activation of Ras, Raf, and MEK. On the contrary, tyrosine phosphorylation of tyrosine kinase receptors was not observed. These results indicate that calmodulin inhibits ERK2 activation pathway at the level of Ras. Calmodulin inhibition induced overexpression of p21(cip1) which was dependent on MEK activity. We propose that inhibition of Ras by calmodulin prevents the activation of ERK2 at low serum concentration. Thus, entering into the cell cycle after serum addition would imply the overcoming of the inhibitory effect of calmodulin and consequently ERK2 activation. Furthermore, down-regulation of Ras by calmodulin may be also important to determine the duration of ERK2 activation and to prevent a high p21(cip1) expression that would lead to an inhibition of cell proliferation.

3T3 Cells↗
PubMed1998

Platelet glycoprotein IIb/IIIa genetic polymorphism is associated with plasma fibrinogen levels in myocardial infarction patients. The REGICOR Investigators.

Fibrinogen is the major ligand of platelet glycoprotein IIb/IIIa platelet receptor. Genes coding for platelet fibrinogen receptor glycoprotein IIb/IIIa are polymorphic. The PLA alloantigen has two antigenic determinants, PLA1 and PLA2, located in a 17-23 kD fragment of glycoprotein IIIa. We analyzed whether PLA genotype has any effect on plasma fibrinogen concentration and investigated if the effect has different magnitude in myocardial infarction patients compared with subjects free of angina or myocardial infarction. One hundred sixteen consecutive patients who suffered a myocardial infarction and 136 subjects recruited by random sampling from the local census were included in the study. PLA genotype distribution and allele frequencies in patients did not significantly differ from those in the control group. Mean fibrinogen concentration tended to be higher in controls with genotype PLA1PLA1 than in those with genotype PLA1PLA2 or PLA2PLA2, and in patients this difference reached statistical significance (p < 0.001). We conclude that the PLA polymorphism may be in linkage disequilibrium with another functional mutation in or near the promoter area of the fibrinogen gene or even in another gene, which controls the production or the clearance of fibrinogen.

Chi-Square Distribution↗
PubMed1998

The relationship between smoking and triglyceride-rich lipoproteins is modulated by genetic variation in the glycoprotein IIIa gene.

In the last year, several studies have reported conflicting results concerning an association between the PI(A2) allele of the PI(A1/A2) polymorphism of platelet glycoprotein IIIa and the risk of myocardial infarction. In the present study, we analyzed the hypothesis of whether glycoprotein IIIa genotypes have any association with lipids and lipoproteins as classical cardiovascular risk factors. Smoking, associated with changes in triglyceride-rich lipoprotein (TRL) concentrations and with both hypercoagulability and reduced fibrinolysis, was also analyzed as an environmental factor. Blood samples were obtained from 170 subjects (83 men and 87 women; mean age, 57 years; SD 15) recruited by random sampling from the census of Girona, Spain. Subjects were classified as current smokers (n=41) and nonsmokers or exsmokers (n=129). Whereas no differences were found in lipid and lipoprotein concentrations between smokers and nonsmokers in subjects with the PI(A1/A1) genotype, smokers with the PI(A1/A2) or PI(A2/A2) genotypes showed significantly higher triglyceride and very-low-density lipoprotein (VLDL) triglyceride concentrations than nonsmokers or exsmokers with the same genotypes. Similarly, the VLDL triglyceride/HDL cholesterol ratio was significantly different in subjects with the PI(A1/A2) or PI(A2/A2) genotypes stratified according to smoking status. Further analysis revealed a significant interaction between smoking and genotype when those homozygous for the allele PI(A1) were compared with one or two PI(A2) alleles for the three lipidic parameters. The observed effects appear to show links between smoking, triglyceride metabolism, and a glycoprotein involved in platelet aggregation. It is likely that the pI(A) polymorphism is in linkage disequilibrium with other functional mutations that might influence triglyceride metabolism under some environmental factors such as smoking. This finding may provide a new perspective in the complex relationship between glycoprotein IIIa gene, environment, and their interactions.

Adult↗
PubMed1998

[Anthropometric and dietary determinants of blood levels of HDL cholesterol in a population-based study. The REGICOR study. Researchers of the REGICOR study].

OBJECTIVES: The aim of the present study was to identify dietary and anthropometric factors influencing HDL cholesterol levels in the region of Girona. POBLATION AND METHODS: A cross-sectional study was designed with random recruitment and 798 men and 862 women were included. Anthropometric variables were collected, the energy expenditure in physical activity was calculated and a dietary questionnaire was supplied in order to obtain nutritional data. Furthermore, lipid levels and lipoprotein concentrations were determined. RESULTS: Significant differences were found in serum triglycerides, body mass index, glucose levels and alcohol intake between the upper and the lower tertils of HDL cholesterol in both men and women. In men, energy expenditure in physical activity was significantly associated with HDL cholesterol levels, as well as total fat and monounsaturated fat. In women, together with the waist-to-hip ratio and fasted glycemia, vitamin C was the dietary factor positively associated with HDL cholesterol levels. CONCLUSIONS: Moderate alcohol intake, physical activity, vitamin C consumption and optimizing body weight strongly contribute to increased HDL cholesterol levels in our region.

Adult↗