Biomedical subjects

B Gonzalez

Publications and source records attributed to B Gonzalez.

At least 19 recordsLinked to original sources

PubMed2007

6q deletion in Waldenström macroglobulinemia is associated with features of adverse prognosis.

Fluorescence in situ hybridisation (FISH) is an effective technique for the cytogenetic analysis of Waldenström macroglobulinemia (WM), but the potential impact of molecular cytogenetics on disease evolution and as a prognostic marker is still unknown. Deletion of the long arm of chromosome 6 (6q-) is the most frequent cytogenetic abnormality in WM. This study analysed the prevalence of this aberration in 102 WM patients, and correlated it with disease characteristics. The incidence of 6q21 deletion was 7% by conventional cytogenetics and 34% when analysed by FISH (54% when cytoplasmic immunoglobulin M-FISH was used). Patients with deletion of 6q displayed features of adverse prognosis, such as higher levels of beta2-microglobulin and monoclonal paraprotein and a greater tendency to display anaemia and hypoalbuminemia. Interestingly, there was a correlation between the presence of 6q deletion and the International Staging System prognostic index (incidence of 6q- among patients stratified in stages 1, 2 and 3 was 24%, 42% and 67% respectively). Those patients diagnosed with smouldering WM who displayed the abnormality showed a trend to an earlier requirement of treatment. Finally, the survival analysis did not show differences between the two groups of patients, probably due to the short follow up of our series.

Adult↗

PubMed2006

Delayed neurodegeneration and early astrogliosis after excitotoxicity to the aged brain.

Excitotoxicity is well recognised as a mechanism underlying neuronal cell death in several brain injuries. To investigate age-dependent differences in neurodegeneration, edema formation and astrogliosis, intrastriatal N-methyl-d-aspartate injections were performed in young (3 months) and aged (22-24 months) male Wistar rats. Animals were sacrificed at different times between 12h and 14 days post-lesion (DPL) and cryostat sections were processed for Toluidine blue, Fluoro-Jade B staining, NeuN and GFAP immunohistochemistry. Our results show that both size of tissue injury and edema were reduced in the old subjects only up to 1DPL, correlating with a slower progression of neurodegeneration with peak numbers of degenerating neurons at 3DPL in the aged, contrasting with maximum neurodegeneration at 1DPL in the young. However, old animals showed an earlier onset of astroglial response, seen at 1DPL, and a larger area of astrogliosis at all time-points studied, including a greater glial scar. In conclusion, after excitotoxic striatal damage, progression of neurodegeneration is delayed in the aged but the astroglial response is earlier and exacerbated. Our results emphasize the importance of using aged animals and several survival times for the study of acute age-related brain insults.

Aging↗

PubMed2004

Retransplantation for hepatitis C-related cirrhosis under long-term pegylated interferon therapy.

INTRODUCTION: Because of an increased organ shortage, one of the most controversial questions is whether hepatic retransplantation should be offered to transplant recipients with hepatitis C virus (HCV)-related graft failure because of their worse survival and the inevitable denial of other patients to access to primary transplantation. The objective of the present study was to review our experience with HCV-infected transplant recipients undergoing re-orthotopic liver transplantation (OLT) for HCV graft cirrhosis and receiving pegylated interferon and ribavirin on a prophylactic basis. RESULTS: With a median follow-up of 26 months, all 5 patients are alive with stable graft function. Four patients are still receiving pegylated interferon at a mean duration of 20 months (range, 15-32 months). Although none of the patients has cleared HCV RNA by polymerase chain reaction the mean serum levels have decreased significantly when compared with pre-retransplantation amounts. One year after re-OLT, both grade and fibrosis stage had significantly decreased; the rate of post-retransplantation fibrosis progression was significantly lower than that pre-retransplantation (3.4 +/- 0.2 vs 0.6 +/- 0.3; P <.05).

Adult↗

PubMed2001

Serum cholesterol, suicidal behavior and impulsivity in cocaine-dependent patients.

Relationships between serum cholesterol and suicidal behavior have been reported. As suicidal behavior is common in cocaine dependence, we looked for a relationship with serum cholesterol. To do this, we compared 57 cocaine-dependent patients who had attempted suicide with 111 cocaine-dependent patients who had never attempted suicide for their admission total serum cholesterol levels. We found that there were no significant differences between cocaine-dependent patients who had or had not attempted suicide in their total serum cholesterol levels. Also, there were no significant correlations between total serum cholesterol levels and scores on the Barratt Impulsivity Scale. Thus, admission total serum cholesterol does not appear to be clinically useful in the assessment of suicidal behavior in cocaine-dependent patients.

Adult↗

PubMed2001

Posterior corneal surface changes after refractive surgery.

OBJECTIVE: To determine the frequency of changes in posterior corneal surface after laser in situ keratomileusis (LASIK) and photorefractive keratectomy (PRK). DESIGN: Nonrandomized, comparative trial. PARTICIPANTS: Ninety-five eyes (71 patients) that underwent PRK (n = 45) or LASIK (n = 50). CONTROLS: Twenty nonsurgery eyes were used to validate the method of analysis of the posterior corneal curvature (PCC). Seventy nonsurgery eyes were used for comparisons. METHODS: Float, apex-fixed best fit corneal curvature (ABC), and posterior elevation difference were evaluated in 20 elevation topography maps at 6 zone diameters (3-7 and 10 mm) and at two time points. Corneal elevation maps before and after PRK or LASIK were analyzed by the ABC and float methods and compared with a nonsurgery group. MAIN OUTCOME MEASURES: Posterior corneal curvature change (mm) was classified as flattening, steepening, or no change. RESULTS: Flattening of more than 0.12 mm was found in 22.2% of eyes (n = 10) in the PRK group, a change of +/-0.12 mm was found in 53.3% of eyes (n = 24), and steepening of more than 0.12 mm was found in 24.4% of eyes (n = 11) using the float method and in 28.9% of eyes (n = 13), 35.6% of eyes (n = 16), and 35.6% eyes (n = 16), respectively, using the ABC method. In the LASIK group, the float method registered flattening in 20% of eyes (n = 10), no change in 52% of eyes (n = 26), and steepening in 28% of eyes (n = 14), whereas the ABC method registered flattening in 30% of eyes (n = 15), no change in 40% of eyes (n = 20), and steepening in 30% of eyes (n = 15). The nonsurgery group showed a similar change in PCC at two different time points similar to that of the PRK and the LASIK groups. CONCLUSIONS: The differences observed in the PCC after PRK or LASIK were not statistically significantly different from those observed over time in the nonsurgery control group.

Adult↗

PubMed2001

Cholesterol and serotonin indices in depressed and suicidal patients.

BACKGROUND: Prolactin and cortisol responses to d-fenfluramine challenge of central serotonin are reduced in depressed and suicidal patients. Low serum cholesterol levels are also reported in suicidal behavior. Thus, we examined for a relationship between serum cholesterol and fenfluramine challenge responses in patients with depression and/or attempted suicide. METHODS: We studied 12 patients and six controls. Blood was drawn for baseline serum cholesterol and the d-fenfluramine challenge test performed. RESULTS: Serum cholesterol levels were significantly lower in suicidal patients than in either non-suicidal patients or controls. However, neither the prolactin nor cortisol responses to d-fenfluramine correlated significantly with serum cholesterol levels. CONCLUSION: No relationship was found between serum cholesterol and these peripheral indices of serotonergic function.

Adult↗

PubMed2000

Carbonyl reductase.

Carbonyl reductase (secondary-alcohol:NADP(+) oxidoreductase, EC 1.1. 1.184) belongs to the family of short chain dehydrogenases/reductases (SDR). Carbonyl reductases (CBRs) are NADPH-dependent, mostly monomeric, cytosolic enzymes with broad substrate specificity for many endogenous and xenobiotic carbonyl compounds. They catalyze the reduction of endogenous prostaglandins, steroids, and other aliphatic aldehydes and ketones. They also reduce a wide variety of xenobiotic quinones derived from polycyclic aromatic hydrocarbons. CBR reduces the anthracycline anticancer drugs, daunorubicin(dn) and doxorubicin (dox) to their C-13 hydroxy metabolites, changing the pharmacological properties of these drugs. Emerging data on CBRs over the last several years is generating new insights on the potential involvement of CBRs in a variety of cellular and molecular reactions associated with drug metabolism, detoxication, drug resistance, mutagenesis, and carcinogenesis.

Alcohol Oxidoreductases↗

PubMed2000

Comparative distribution of pituitary adenylate cyclase-activating polypeptide (PACAP) binding sites and PACAP receptor mRNAs in the rat brain during development.

The distribution and density of pituitary adenylate cyclase-activating polypeptide (PACAP) binding sites as well as PACAP-specific receptor 1 (PAC1-R), vasoactive intestinal polypeptide/PACAP receptor 1 (VPAC1-R), and VPAC2-R mRNAs have been investigated in the rat brain from embryonic day 14 (E14) to postnatal day 8 (P8). Significant numbers of binding sites for the radioiodinated, 27-amino-acid form of PACAP were detected as early as E14 in the neuroepithelia of the metencephalon and the myelencephalon. From E14 to E21, the density of binding sites in the germinative areas increased by 3- to 5-fold. From birth to P12, the density of binding sites gradually declined in all neuroepithelia except in the external granule cell layer of the cerebellum, where the level of binding sites remained high during the first postnatal weeks. Only low to moderate densities of PACAP binding sites were found in regions other than the germinative areas, with the exception of the internal granule cell layer of the cerebellum, which contained a high density of sites. The localization of PACAP receptor mRNAs was investigated by in situ hybridization using [(35)S] uridine triphosphate-specific riboprobes. The evolution of the distribution of PAC1-R and VPAC1-R mRNAs was very similar to that of PACAP binding sites, the concentration of VPAC1-R mRNA being much lower than that of PAC1-R mRNA. In contrast, intense expression of VPAC2-R mRNA was observed in brain regions other than germinative areas, such as the suprachiasmatic, ventral thalamic, and dorsolateral geniculate nuclei. The discrete localization of PACAP binding sites as well as PAC1-R and VPAC1-R mRNAs in neuroepithelia during embryonic life and postnatal development strongly suggests that PACAP, acting through PAC1-R and/or VPAC1-R, may play a crucial role in the regulation of neurogenesis in the rat brain.

Aging↗

PubMed2000

Human carbonyl reductase overexpression in the heart advances the development of doxorubicin-induced cardiotoxicity in transgenic mice.

Doxorubicinol (dxol) is the major metabolite formed in the hearts of cancer patients being treated with the widely used chemotherapeutic agent, doxorubicin (dox). The well-documented cardiomyopathy associated with dox treatment has been studied in vitro and ex vivo providing evidence that the C-13 hydroxy metabolite, dxol, might play a key role in the development of dox-induced cardiotoxicity. In this report, we have developed transgenic mice with heart-specific expression of human carbonyl reductase (HCBR), an enzyme that metabolizes dox to dxol. Dox was rapidly converted to dxol in the hearts of the transgenic expressers, which led to advanced development of both acute and chronic cardiotoxicity. Acute cardiotoxicity was evident by a 60% increase in serum creatine kinase activity and a 5-fold increase in cardiac damage measured by electron microscopy. Myofibril degeneration was the major damage observed in acute dox toxicity. Electrocardiograph telemetry, survival data, and electron microscopy were monitored during chronic dox-induced cardiotoxicity. HCBR expressers developed cardiotoxicity 6-7 weeks before the nonexpressers. The HCBR expressers survived for 5 weeks compared with 12 weeks for the controls. Electrocardiograph profiles and necropsies showed the cause of death to be the development of cardiomyopathies leading to congestive heart failure. Levels of dxol were four times higher in the HCBR expresser hearts than in the nonexpressers. Electron microscopy data showed swelling and major structural damage of the mitochondria in the HCBR expressers. These data demonstrate that the C-13 hydroxy metabolite of dox advances the development of dox-induced cardiotoxicity in an in vivo system and suggest that heart carbonyl reductase activity may contribute to dox-induced cardiotoxicity in humans.

Alcohol Oxidoreductases↗

PubMed2000

Directed evolution of beta -glucosidase A from Paenibacillus polymyxa to thermal resistance.

The beta-glucosidase encoded by the bglA gene from Paenibacillus polymyxa has a half-life time of 15 min at 35 degrees C and no detectable activity at 55 degrees C. We have isolated random mutations that enhance the thermoresistance of the enzyme. Following a directed evolution strategy, we have combined some of the isolated mutations to obtain a beta-glucosidase with a half-life of 12 min at 65 degrees C, in the range of resistance of thermophilic enzymes. No significant alteration of the kinetic parameters of the enzyme was observed. One of the mutants isolated in the screening for thermoresistant beta-glucosidase had the same resistance to denaturation as the wild type. This mutation caused the accumulation of enzyme in E. coli, probably due to its lower turnover. The structural changes responsible for the properties of the mutant enzymes have been analyzed. The putative causes increasing thermoresistance are as follows: the formation of an extra salt bridge, the replacement of an Asn residue exposed to the solvent, stabilization of the hydrophobic core, and stabilization of the quaternary structure of the protein.

Adaptation, Physiological↗

PubMed2000

Dynamic in vivo (31)P nuclear magnetic resonance study of Saccharomyces cerevisiae in glucose-limited chemostat culture during the aerobic-anaerobic shift.

The purpose of this work was to analyse in vivo the influence of sudden oxygen depletion on Saccharomyces cerevisiae, grown in glucose-limited chemostat culture, using a recently developed cyclone reactor coupled with (31)P NMR spectroscopy. Before, during and after the transition, intracellular and extracellular phosphorylated metabolites as well as the pHs in the different cellular compartments were monitored with a time resolution of 2.5 min. The employed integrated NMR bioreactor system allowed the defined glucose-limited continuous cultivation of yeast at a density of 75 g DW/l and a p(O(2)) of 30% air saturation. A purely oxidative metabolism was maintained at all times. In vivo (31)P NMR spectra obtained were of excellent quality and even allowed the detection of phosphoenolpyruvate (PEP). During the switch from aerobic to anaerobic conditions, a rapid, significant decrease of intracellular ATP and PEP levels was observed and the cytoplasmic pH decreased from 7.5 to 6.8. This change, which was accompanied by a transient influx of extracellular inorganic phosphate (P(i)), appeared to correlate linearly with the decrease of the ATP concentration, suggesting that the cause of the partial collapse of the plasma membrane pH gradient was a reduced availability of ATP. The complete phosphorous balance established from our measurement data showed that polyphosphate was not the source of the increased intracellular P(i). The derived intracellular P(i), ATP and ADP concentration data confirmed that the glycolytic flux at the level of glyceraldehyde-3-phosphate dehydrogenase, 3-phosphoglycerate kinase and enolase enzymes is mainly controlled by thermodynamic constraints.

Adenosine Diphosphate↗

PubMed2000

Glycochenodeoxycholic acid (GCDC) induced hepatocyte apoptosis is associated with early modulation of intracellular PKC activity.

The effect of GCDC-induced apoptosis on PKC activity and PKC's role in GCDC-induced hepatocyte apoptosis is unclear. The specific aims of this study were to determine if GCDC-induced apoptosis changed intracellular PKC activity and if modulation of PKC activity affected GCDC-induced hepatocyte apoptosis. Apoptosis was induced in isolated hepatocytes using GCDC. PKC activity was measured and specific PKC and calpain inhibitors were used to study the effects of PKC and calpain modulation on GCDC-induced apoptosis. After 4 h exposure, 50 microM GCDC induced apoptosis in 42% of hepatocytes. Intracellular PKC activity decreased to 44% of controls 2 h after exposure of hepatocytes to GCDC (p < 0.001). Pre-incubation of hepatocytes with the calpain protease inhibitor restored PKC activity in GCDC exposed hepatocytes to 91 +/- 5% of control cells. Pre-incubation of hepatocytes with a calpain inhibitor decreased GCDC-induced apoptosis as did pre-incubation with the PKC activating phorbol ester, PMA. The combination of calpain inhibition and PMA further reduced GCDC-induced apoptosis but caused low level hepatic apoptosis. Inhibition of PKC with chelerythrine also substantially reduced GCDC-induced hepatocyte apoptosis. GCDC-induced apoptosis is associated with decreases in total cellular PKC activity, which appear to be dependent on intracellular calpain-like protease activity. The combination of protease inhibition and phorbol ester pretreatment preserved total cellular PKC activity and decreased GCDC-induced apoptosis but induced low level apoptosis in the absence of GCDC exposure. PKC inhibition also decreased GCDC-induced hepatocyte apoptosis highlighting the complex interactions of PKC and proteases during GCDC-induced apoptosis.

Animals↗

PubMed2000

Metabolism of n -9, n -6 and n -3 fatty acids in hepatoma Morris 7777 cells. Preferential accumulation of linoleic acid in cardiolipin.

The objective of this study was to investigate, using a pulse-chase technique, the different incorporation of (1-(14)C) n -9, n -6 and n 3 fatty acids into hepatoma lipids and their secretion to the culture medium. Docosahexaenoic acid (DHA) accumulated preferentially into the triacylglycerol while arachidonic acid (AA) did into the phospholipid fraction. DHA was poorly secreted to the culture medium whereas AA was secreted to a large extent. The fatty acids were initially esterified mainly into phosphatidylcholine and phosphatidylethanolamine. During the 24 h chase, a general shift from phosphatidylcholine to phosphatidylethanolamine was observed. Linoleic acid was esterified in cardiolipin to a much greater extent than any other fatty acid and it was not converted to more polyunsaturated fatty acids. The supplementation of the culture medium with polyunsaturated fatty acids had no inhibitory effect on the growth of the hepatoma cells, in marked contrast to observations made in other tumoral cells. The reasons for the resistance of the hepatoma cells to polyunsaturated fatty acid toxicity, including the possible antioxidant effect of linoleic acid accumulation in cardiolipin, are also discussed.

Albumins↗

PubMed2000

Expression of a complete and functional complement system by human neuronal cells in vitro.

We demonstrate in vitro expression of complement components, i.e. C3, factor H (FH), factor B (FB), C4, C1-inhibitor (C1-inh), C1q, C5, C6, C7 and C9, by four human neuroblastoma cell lines IMR32, SKNSH, SH-SY5Y and KELLY. Activating proteins C4, C9 and C1q, and regulatory proteins FH and C1-inh were produced constitutively by the four cell lines. C3, C6 and FB were mainly produced by SKNSH and SH-SY5Y. Western blot experiments showed that secreted proteins were structurally similar to their serum counterparts. An additional polypeptide of 43 kDa with FH immunoreactivity was detected, which could correspond to the N-terminal truncated form found in plasma. Regulation of complement expression by inflammatory cytokines, lipopolysaccharide and dexamethasone was tested in vitro. These factors had no significant effects on activating synthesis of components C3, FB and C4, but expression of regulating components C1-inh and FH was strongly increased particularly by IFN-gamma and tumor necrosis factor-alpha. The rate of synthesis of complement components was dependent on the differentiation of neuroblastoma cells. This effect of differentiation was also observed on normal rat neurons. Rat cerebellar granule cells constitutively expressed mRNA for C4 and C1q, but expression of C3 mRNA was induced by differentiation. This study shows that neurons could be another local source of complement in the brain, besides astrocytes and microglia. Human neuroblastoma cell lines can constitute an interesting model to analyze complement biosynthesis by human neurons. Local complement expression by neurons in vivo may be implicated in some physio-pathological processes.

Animals↗

PubMed2000

Radiotoxicity of h-R3 monoclonal antibody labeled with 188Re administered intracerebrally in rats.

Brain tumors are often incurable despite current aggressive treatment modalities. Regional intracerebral administration of labeled monoclonal antibodies (Mabs) can maximize the radioisotope and Mab concentration to tumor sites while reducing systemic toxicity. h-R3 is a humanized antiepidermal growth factor receptor Mab that successfully targets the epidermal growth factor receptor, which is overexpressed in glioblastomas. We studied the acute local and systemic toxicity effects of intraventricular 188Re-h-R3 in rats. Forty rats were distributed into four groups with five animals of each sex in each group. A single 5 -microl dose (2.5 microl into the left and 2.5 microl into the right lateral ventricles) of neutral solution containing 50 microg of h- R3 labeled with 49.5 +/- 1.7,284 +/- 13.7 or 579 +/- 23.7 muCi of 188Re were stereotactically administered to each animal. Control animals received vehicle alone. Each animal was observed twice daily for detection of toxicity signs. Body weights were recorded on days 0, 7 and 14. Blood samples for analysis of hematological and clinical chemistry parameters were taken on days 0 and 14. Necropsy and histopathological studies were carried out after completion of the study. All animals, but one, remained clinically stable. Toxicities included local radionecrosis, discrete increase in ALAT and creatinine blood values at higher dose level. We concluded that a single intraventricular administration of relatively large doses of 188Re-h-R3 is tolerable and causes minimal local and systemic toxicity effects in rats. Nevertheless, further studies are necessary to discard learning and behavioral problems.

Adenocarcinoma↗

PubMed1999

Characterization and localization of pituitary adenylate cyclase-activating polypeptide (PACAP) binding sites in the brain of the frog Rana ridibunda.

The biochemical characteristics and the distribution of pituitary adenylate cyclase-activating polypeptide (PACAP) binding sites have been investigated in the brain of the frog Rana ridibunda by using [(125)I]PACAP27 as a radioligand. Membrane-binding studies revealed the existence of high-affinity receptors for frog PACAP38 and PACAP27. In contrast, the [Des-His(1)]PACAP38 analogue had a much lower affinity and vasoactive intestinal polypeptide did not produce any displacement of the binding. Autoradiographic labeling of frozen brain sections revealed that the highest concentrations of PACAP receptors were located in the olfactory bulb, pallium, striatum, habenular nuclei, ventromedial thalamic nucleus, corpus geniculatum, posterior tubercle, dorsal part of the magnocellular preoptic nucleus, tectum, and the molecular cell layer of the cerebellum. Moderate binding was observed in the septum, in most parts of the thalamus, the dorsal hypothalamic nucleus, the median eminence, the ventral nuclei of the tegmentum, the torus semicircularis, and the interpeduncular and isthmi nuclei. The present data provide the first biochemical characterization and anatomic distribution of PACAP binding sites in the brain of a nonmammalian vertebrate species. The widespread distribution of specific PACAP receptors in the frog brain suggests that the peptide does not act solely as a hypophysiotropic factor, but likely fulfills neurotransmitter functions, neuromodulator functions, or both.

Animals↗

PubMed1999

Checklist for ruling out pregnancy among family-planning clients in primary care.

Where pregnancy tests are unavailable, health providers, fearing possible harm to fetuses, often deny contraception to nonmenstruating clients. In Kenya, a trial of a simple checklist to exclude pregnancy showed a good negative predictive value, which could improve access to service and reduce unwanted pregnancies and their sequelae.

Diagnosis, Differential↗

PubMed1999

Dynamic responses of reserve carbohydrate metabolism under carbon and nitrogen limitations in Saccharomyces cerevisiae.

The dynamic responses of reserve carbohydrates with respect to shortage of either carbon or nitrogen source was studied to obtain a sound basis for further investigations devoted to the characterization of mechanisms by which the yeast Saccharomyces cerevisiae can cope with nutrient limitation during growth. This study was carried out in well-controlled bioreactors which allow accurate monitoring of growth and frequent sampling without disturbing the culture. Under glucose limitation, genes involved in glycogen and trehalose biosynthesis (GLG1, GSY1, GSY2, GAC1, GLC3, TPS1), in their degradation (GPH1, NTHI), and the typical stress-responsive CTT1 gene were coordinately induced in parallel with glycogen, when the growth has left the pure exponential phase and while glucose was still plentiful in the medium. Trehalose accumulation was delayed until the diauxic shift, although TPS1 was induced much earlier, due to hydrolysis of trehalose by high trehalase activity. In contrast, under nitrogen limitation, both glycogen and trehalose began to accumulate at the precise time when the nitrogen source was exhausted from the medium, coincidentally with the transcriptional activation of genes involved in their metabolism. While this response to nitrogen starvation was likely mediated by the stress-responsive elements (STREs) in the promoter of these genes, we found that these elements were not responsible for the co-induction of genes involved in reserve carbohydrate metabolism during glucose limitation, since GLG1, which does not contain any STRE, was coordinately induced with GSY2 and TPS1.

Blotting, Northern↗