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Biomedical subjects

Antonio González

Publications and source records attributed to Antonio González.

At least 19 recordsLinked to original sources

[Evolution of the bone mass of hypertense menopausal women in treatment with fosinopril].

BACKGROUND AND OBJECTIVE: The renin-angiotensin system (SRA) acts on the bone metabolism and decreases the mineralization. Menopausal women frequently are hypertense and have risk of developing osteoporosis. The inhibition of SRA could favour the mineralization and protect the bone mass of hypertense women in treatment with antihypertensive drugs that are angiotensin converting enzyme inhibitors. PATIENTS AND METHOD: Cohorts prospective study. 50 menopausal women were recruited and divided in one cohort of non hypertense patients and one cohort of hypertense women who initiated antihypertensive treatment with oral fosinopril. Baseline and after 1 year bone mineral density of lumbar spine and femoral neck was made. RESULTS: There were no significant differences between the bone mass of both groups. Significant changes between the baseline and after the treatment were not demonstrated in the cohort exposed. In the group of non exposed women were demonstrated differences in lumbar spine (baseline, 0.874 g/cm(2); final, 0.854 g/cm(2); p = 0.002) and femoral neck (baseline, 0.743 g/cm(2); final, 0.725 g/cm(2); p = 0.016). CONCLUSIONS: The menopausal and hypertense women who followed treatment with fosinopril did not present the physiological loss of bone mass that affected to menopausal women without treatment.

Absorptiometry, Photon↗

H2O2 mobilizes Ca2+ from agonist- and thapsigargin-sensitive and insensitive intracellular stores and stimulates glutamate secretion in rat hippocampal astrocytes.

The effect of hydrogen peroxide (H2O2) on cytosolic free calcium concentration ([Ca2+]c) as well as its effect on glutamate secretion in rat hippocampal astrocytes have been the aim of the present research. Our results show that 100 microM H2O2 induces an increase in [Ca2+]c, that remains at an elevated level while the oxidant is present in the perfusion medium, due to its release from intracellular stores as it was observed in the absence of extracellular Ca2+, followed by a significant increase in glutamate secretion. Ca2+-mobilization in response to the oxidant could only be reduced by thapsigargin plus FCCP, indicating that the Ca2+-mobilizable pool by H2O2 includes both endoplasmic reticulum and mitochondria. We conclude that ROS in hippocampal astrocytes might contribute to an elevation of resting [Ca2+]c which, in turn, could lead to a maintained secretion of the excitatory neurotransmitter glutamate, which has been considered a situation potentially leading to neurotoxicity in the hippocampus.

Animals↗

Hemodynamic response-guided therapy for prevention of variceal rebleeding: an uncontrolled pilot study.

The clinical usefulness of assessing hemodynamic response to drug therapy in the prophylaxis of variceal rebleeding is unknown. An open-labeled, uncontrolled pilot trial was performed to evaluate the feasibility and efficacy of using the hemodynamic response to pharmacological treatment to guide therapy in this setting. Fifty patients with acute variceal bleeding underwent a hepatic venous pressure gradient (HVPG) measurement 5 days after the episode. Nadolol and nitrates were initiated, and a second HVPG was measured 15 days later. Responder patients (> or =20% decrease in HVPG from baseline) were maintained on drugs, partial responders (> or =10% and <20%) had banding ligation added to the drugs, and nonresponders (<10%) received a transjugular intrahepatic portal-systemic shunt (TIPS). Mean follow-up was 22 months. Eight patients (16%) did not receive the second HVPG, 6 of them because of early variceal rebleeding. Of the other 42 patients, 24 were classified as responders (57%); 10 as partial responders (24%), who had banding added; and 8 as nonresponders (19%), who received a TIPS. Patients with cirrhosis of viral etiology compared to alcoholic cirrhosis tended to present more early rebleedings, less response to drugs and needed more TIPS. Variceal rebleeding occurred in 22% of all patients but only in 12% of patients whose hemodynamic response was assessed. The 3 therapeutic groups were not different. In conclusion, using hemodynamic response to pharmacological treatment to guide therapy in secondary prophylaxis to prevent variceal bleeding is feasible and effectively protects patients from rebleeding. In this context, viral cirrhosis seems to present a worse outcome than alcoholic cirrhosis.

Adrenergic beta-Antagonists↗

Ethanol impairs CCK-8-evoked amylase secretion through Ca2+-mediated ROS generation in mouse pancreatic acinar cells.

In the present study, we have investigated the effect of ethanol on amylase release in response to cholecystokinin octapeptide (CCK-8). We have also studied the effect of ethanol on cytosolic free Ca(2+) concentration ([Ca(2+)](c)) and reactive oxygen species (ROS) production by loading of cells with fura-2 and 5-(and-6)-chloromethyl-2',7'-dichlorodihydrofluorescein diacetate, acetyl ester (CM-H(2)DCFDA), respectively. Our results show that stimulation of pancreatic acinar cells with CCK-8 induced a dose-dependent amylase secretion, resulting in a maximum at 0.3nM of 19.39+/-2.73% of the total content of amylase. Treatment of pancreatic acini with ethanol did not induce any significant effect on amylase release at a wide range of concentrations (1-50mM). In contrast, incubation of cells with 50mM ethanol clearly reduced amylase release stimulated by CCK-8. The inhibitory effect of ethanol on CCK-8-induced amylase secretion was abolished by dithiothreitol, a sulfhydryl reducing agent. Ethanol induced an increase in [Ca(2+)](c) resulting in a level higher than the prestimulation level both in the presence and in the absence of extracellular Ca(2+). Additionally, ethanol led to an increase in fluorescence of CM-H(2)DCFDA, reflecting an increase in oxidation. A decrease in oxidation was observed in the absence of extracellular Ca(2+) and in the presence of ethylene glycol-bis(2-aminoethylether)-N,N,N',N'-tetraacetic acid. Similarly, when the cells were challenged in the presence of the intracellular Ca(2+) chelator 1,2-Bis(2-amino-5-methylphenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA) and in the absence of extracellular Ca(2+), the responses to ethanol were reduced, although not completely inhibited. Taken together, our results suggest that ethanol induces generation of ROS by a Ca(2+)-dependent mechanism and reduces CCK-8-evoked amylase secretion in exocrine pancreatic cells.

Amylases↗

Dose-dependent effect of hydrogen peroxide on calcium mobilization in mouse pancreatic acinar cells.

We have employed confocal laser scanning microscopy to investigate how intracellular free calcium concentration ([Ca2+]i) is influenced by hydrogen peroxide (H2O2) in collagenase-dispersed mouse pancreatic acinar cells. In the absence of extracellular calcium, treatment of cells with increasing concentrations of H2O2 resulted in an increase in [Ca2+]i, indicating the release of calcium from intracellular stores. Micromolar concentrations of H2O2 induced an oscillatory pattern, whereas 1 mmol H2O2/L caused a slow and sustained increase in [Ca2+]i. H2O2 abolished the typical calcium release stimulated by thapsigargin or by the physiological agonist cholecystokinin octapeptide (CCK-8). Depletion of either agonist-sensitive or mitochondrial calcium pools was unable to prevent calcium release induced by 1 mmol H2O2/L, but depletion of both stores abolished it. Additionally, lower H2O2 concentrations were able to release calcium only after depletion of mitochondrial calcium stores. Treatment with either the phospholipase C inhibitor U-73122 or the inhibitor of the inositol 1,4,5-trisphosphate (IP3) receptor xestospongin C did not modify calcium release from the agonist-sensitive pool induced by 100 micromol H2O2/L, suggesting the involvement of a mechanism independent of IP3 generation. In addition, H2O2 reduced amylase release stimulated by CCK-8. Finally, either the H2O2-induced calcium mobilization or the inhibitory effect of H2O2 on CCK-8-induced amylase secretion was abolished by dithiothreitol, a sulphydryl reducing agent. We conclude that H2O2 at micromolar concentrations induces calcium release from agonist-sensitive stores, and at millimolar concentrations H2O2 can also evoke calcium release from the mitochondria. The action of H2O2 is mediated by oxidation of sulphydryl groups of calcium ATPases independently of IP3 generation.

Animals↗

Partial protection against collagen antibody-induced arthritis in PARP-1 deficient mice.

Poly(ADP-ribose) polymerase-1 (PARP-1) is a nuclear DNA-binding protein that participates in the regulation of DNA repair and maintenance of genomic integrity. In addition, PARP-1 has a role in several models of inflammation disease, where its absence or inactivation confers protection. The aim of this study was to analyze the impact of selective PARP-1 suppression in collagen antibody-induced arthritis. We show that PARP-1 deficiency partially reduces the severity of arthritis, although the incidence of disease was similar in control and deficient mice. Decreased clinical scores were accompanied by partial reduction of histopathological findings. Interestingly, quantitative real-time PCR and ELISA analysis revealed that the absence of PARP-1 down-regulated IL-1beta and monocyte chemotactic protein 1 expression in arthritic joints whereas tumor necrosis factor-alpha transcription was not impaired. Our results provide evidence of the contribution of PARP-1 to the progression of arthritis and identify this protein as a potential therapeutic target for the treatment of rheumatoid arthritis.

Animals↗

Involvement of ryanodine-operated channels in tert-butylhydroperoxide-evoked Ca2+ mobilisation in pancreatic acinar cells.

Reactive oxygen species and related oxidative damage have been implicated in the initiation of acute pancreatitis, a disease characterised in its earliest stages by disruption of intracellular Ca2+ homeostasis. The present study was carried out in order to establish the effect of the organic pro-oxidant, tert-butylhydroperoxide (tBHP), on the mobilisation of intracellular Ca2+ stores in isolated rat pancreatic acinar cells and the mechanisms underlying this effect. Cytosolic free Ca2+ concentrations ([Ca2+]c) were monitored using a digital microspectrofluorimetric system in fura-2 loaded cells. In the presence of normal extracellular Ca2+ concentrations ([Ca2+]o), perfusion of pancreatic acinar cells with 1 mmol l-1 tBHP caused a slow sustained increase in [Ca2+]c. This increase was also observed in a nominally Ca2+-free medium, indicating a release of Ca2+ from intracellular stores. Pretreatment of cells with tBHP abolished the typical Ca2+ response of both the physiological agonist CCK-8 (1 nmol l-1) and thapsigargin (TPS, 1 micromol l-1), an inhibitor of the SERCA pump, in the absence of extracellular Ca2+. Similar results were observed with carbonyl cyanide p-trifluoromethoxyphenylhydrazone (FCCP, 0.5 micromol l-1), a mitochondrial uncoupler. In addition, depletion of either agonist-sensitive Ca2+ pools by CCK-8 or TPS or mitochondrial Ca2+ pools by FCCP were unable to prevent the tBHP-induced Ca2+ release. By contrast, simultaneous administration of TPS and FCCP clearly abolished the tBHP-induced Ca2+ release. These results show that tBHP releases Ca2+ from agonist-sensitive intracellular stores and from mitochondria. On the other hand, simultaneous application of FCCP and of 2-aminoethoxydiphenylborane (2-APB), a blocker of IP3-mediated Ca2+ release, was unable to suppress the increase in [Ca2+]c induced by tBHP, while the application of 50 micromol l-1 of ryanodine (which is able to block the ryanodine channels) inhibits tBHP-evoked Ca2+ mobilisation. These findings indicate that tBHP releases Ca2+ from non-mitochondrial Ca2+ pools through ryanodine channels.

Animals↗

The nature of residual cost in regular switch response factors.

Two experiments are presented that compare the residual cost found when switching from one task to another under predictable conditions. The aim of the study was to explore the roles played by the stimulus, the response, or both in the process of the mental set reconfiguration necessary to switch between two tasks. The experiments tested [Rogers, R. D., & Monsell, S. (1995). Cost of a predictable switch between simple cognitive tasks. Journal of Experimental Psychology: General, 124, 207-231] stimulus-cued-completion hypothesis and [Schuch, S., & Koch, I. (2003). The role of response selection for inhibition of task sets in task shifting. Journal of Experimental Psychology: Human Perception and Performance, 29, 92-105] hypothesis of response selection as the key factor in the nature of switch cost. In the first experiment, two conditions were created that varied in terms of a Go/No-Go signal: The Go trials were a replication of [Tornay, F. J., & Milán, E. G. (2001). A more complete task-set reconfiguration in random than in predictable task switch. The Quarterly Journal of Experimental Psychology, 54A, 785-803 Experiment 3]; The No-Go trials were identical to the first condition, except that participants did not execute a response in the trial n-1 (Schuch & Koch, 2003). In addition, the percentage of Go and No-Go trials was manipulated. The results showed that the cost was significant only in the high Go signal-frequency case (Experiment 2), with an abrupt offset in Go trials and a gradual offset in No-Go trials. Based on the results of these experiments, it was concluded that the crucial factor to complete a mental set reconfiguration is response-related and not stimulus-related.

Cues↗

Expressed sequence tags from the plant trypanosomatid Phytomonas serpens.

We have generated 2190 expressed sequence tags (ESTs) from a cDNA library of the plant trypanosomatid Phytomonas serpens. Upon processing and clustering the set of 1893 accepted sequences was reduced to 697 clusters consisting of 452 singletons and 245 contigs. Functional categories were assigned based on BLAST searches against a database of the eukaryotic orthologous groups of proteins (KOG). Thirty six percent of the generated sequences showed no hits against the KOG database and 39.6% presented similarity to the KOG classes corresponding to translation, ribosomal structure and biogenesis. The most populated cluster contained 45 ESTs homologous to members of the glucose transporter family. This fact can be immediately correlated to the reported Phytomonas dependence on anaerobic glycolytic ATP production due to the lack of cytochrome-mediated respiratory chain. In this context, not only a number of enzymes of the glycolytic pathway were identified but also of the Krebs cycle as well as specific components of the respiratory chain. The data here reported, including a few hundred unique sequences and the description of tandemly repeated motifs and putative transcript stability motifs at untranslated mRNA ends, represent an initial approach to overcome the lack of information on the molecular biology of this organism.

Amino Acid Sequence↗

H2O2-induced changes in mitochondrial activity in isolated mouse pancreatic acinar cells.

This study employed confocal laser scanning microscopy to monitor the effect of H2O2 on cytosolic as well as mitochondrial calcium (Ca2+) concentrations, mitochondrial inner membrane potential (psi m) and flavine adenine dinucleotide (FAD) oxidation state in isolated mouse pancreatic acinar cells. The results show that incubation of pancreatic acinar cells with H2O2, in the absence of extracellular Ca2+ ([Ca2+],) led to an increase either in cytosolic and in mitochondrial Ca2+ concentration. Additionally, H2O2 induced a depolarization of mitochondria and increased oxidized FAD level. Pretreatment of cells with the mitochondrial inhibitors rotenone or cyanide inhibited the response induced by H2O2 on mitochondrial inner membrane potential but failed to block oxidation of FAD in the presence of H2O2. However, the H2O2-evoked effect on FAD state was blocked by pretreatment of cells with the mitochondrial uncoupler, carbonyl cyanide p-trifluoromethoxy-phenylhydrazone (FCCP). On the other hand, perfusion of cells with thapsigargin (Tps), an inhibitor of the SERCA pump, led to an increase in mitochondrial Ca2+ concentration and in oxidized FAD level, and depolarized mitochondria. Pretreatment of cells with thapsigargin inhibited H2O2-evoked changes in mitochondrial Ca2+ concentration but not those in membrane potential and FAD state. The present results have indicated that H2O2 can evoke marked changes in mitochondrial activity that might be due to the oxidant nature of H2O2. This in turn could represent the mechanism of action of ROS to induce cellular damage leading to cell dysfunction and generation of pathologies in the pancreas.

Animals↗

The response-cued completion hypothesis and the nature of residual cost in regular switch.

Three experiments are presented that compare the residual cost found when shifting from one task to another under different extra-response conditions, to test whether the response is the main factor to complete mental set reconfiguration. We investigated whether residual costs can be eliminated if participants carry out a response prior to completing switch trials. In all experiments, participants were required to press an extra key during the inter-trial interval (ITI) to proceed. In experiment 1, this extra response consisted of pressing the space bar. In experiment 2, the response consisted of pressing one of the two possible keys that belonged to the alternating tasks response set. In experiment 3, the interpolated response involved pressing one of the two possible keys, not belonging to the response set of the alternating tasks. We found no residual cost in the second or the third experiments. To explain the nature of residual cost we discuss the data in the context of a response cued completion hypothesis.

Cues↗

Effect of H2O2 on CCK-8-evoked changes in mitochondrial activity in isolated mouse pancreatic acinar cells.

BACKGROUND INFORMATION: This paper studies the effect of H(2)O(2) on mitochondrial responses evoked by CCK-8 (cholecystokinin 8) in mouse pancreatic acinar cells. Cytosolic ([Ca(2+)](c)) and mitochondrial ([Ca(2+)](m)) free-calcium concentrations, mitochondrial inner membrane potential (psi(m)) and FAD autofluorescence were monitored using confocal laser scanning microscopy. RESULTS: CCK-8 induced an increase in [Ca(2+)](m) that slowly declined towards the prestimulation level. Depolarization of psi(m) that partially recovered, as well as increases in FAD autofluorescence, could also be observed in response to the hormone. Pretreatment of cells with 1 mM H(2)O(2) alone resulted in marked changes in mitochondrial parameters and, moreover, H(2)O(2) inhibited the CCK-8-evoked changes in [Ca(2+)](m), psi(m) and FAD autofluorescence. The results of the present study have demonstrated that CCK-8 can evoke marked changes in pancreatic acinar cell mitochondrial activity and that CCK-8-evoked responses are blocked by H(2)O(2). Additionally, H(2)O(2) releases Ca(2+) from intracellular stores and inhibits pancreatic acinar cell responses to CCK-8. CONCLUSION: The effects observed reflect an impairment of mitochondrial activity in the presence of H(2)O(2) that could represent some of its mechanisms of action to induce cellular damage leading to cell dysfunction and generation of pathologies.

Animals↗

Immunogenicity and reactogenicity of a combined adsorbed tetanus toxoid, low dose diphtheria toxoid, five component acellular pertussis and inactivated polio vaccine in six-year-old children.

BACKGROUND: The objective of this study was to assess the immunogenicity and reactogenicity of the combined adsorbed tetanus toxoid, low dose diphtheria toxoid, 5-component acellular pertussis and inactivated polio vaccine (TdcP-IPV) as compared with a pediatric dose diphtheria formulation, combined with adsorbed tetanus toxoid and 3-component acellular pertussis (DTacP), in 6-year-old children who were immunized with 4 doses of diphtheria-tetanus-whole cell cellular pertussis (DTwcP) plus oral polio vaccine (OPV) before 2 years of age, according to the local Spanish vaccination calendar. METHODS: One hundred ninety-four healthy 6-year-old children were randomized to receive 1 dose of TdcP-IPV or 1 dose of DTacP and OPV. RESULTS: One month postvaccination, antidiphtheria and antitetanus titers were > or =0.1 IU/mL in 100% of patients in both study groups. TdcP-IPV reached 100% seroprotection rates against polio types 1, 2 and 3. In OPV recipients, these rates were 100, 100 and 96.8%, respectively. Seropositivity rates for pertussis toxin, filamentous hemagglutinin, pertactin and fimbrial components of the TdcP-IPV vaccine were 97.9, 89.6, 90.6 and 100%. The incidence of local and systemic reactions was 50.5 and 39.2% in the TdcP-IPV group and 59.4 and 38.5% in the DTacP plus OPV group, and no serious adverse events were reported. CONCLUSIONS: TdcP-IPV vaccine was shown to be immunogenic and safe when given as a booster in children 6 years of age who were primed with 4 doses of DTwcP and OPV.

Child↗

Exploring task-set reconfiguration with random task sequences.

Switching between two different tasks normally results in an impairment in people's performance known as a switch cost, typically measured as an increase in reaction time (RT) and errors compared to a situation in which no task switch is required. Researchers in task switching have suggested that this switch cost is the behavioural manifestation of the task set reconfiguration processes that are necessary to perform the upcoming task. However, an examination of the literature in task switching reveals apparently contradictory results about the nature of task set reconfiguration processes. In Experiment 1, we addressed this issue by comparing participants' performance in two different experimental conditions: predictable task switching and random task switching. In the predictable switch condition the switch cost completely vanished after the first repetition of the new task. However, in the random switch condition, while the difference between switch and repetition trials was not significant, we observed a significant reduction in RT between the first and second repetition of the new task. In Experiment 2, we further investigated the pattern of task set reconfiguration in the random switch situation. The results showed a progressive reduction of participants' response latencies across repetitions of the same task. The present study demonstrates that, whereas the results in predictable switching conditions are compatible with an exogenous-reconfiguration hypothesis, random task switching produces a more gradual, decay-like switch cost reduction with task repetition.

Analysis of Variance↗

Epidemiology of severe varicella-zoster virus infection in Spain.

Data of hospitalizations for varicella and herpes zoster in Spain during the 1999-2000 period were obtained from the national surveillance system for hospital data. A total of 3083 hospitalizations for varicella and 6324 for herpes zoster were identified, representing an annual incidence of 4.1 and 8.4 per 100,000 persons per year, respectively. Almost half of patients hospitalized for varicella were children under 5 years of age. In contrast, 78% of hospitalizations for zoster occurred in adults >50 years of age. Hospitalizations for varicella and herpes zoster resulted annually in 11,141 and 40,090 days of hospitalization and a cost of 3.2 and 7.0 million, respectively.

Adolescent↗

Incidence of pertussis in persons < or =15 years of age in Valencia, Spain: seroprevalence of antibodies to pertussis toxin (PT) in children, adolescents and adults.

PURPOSE: To determine the incidence of pertussis in persons < or =15 years in age in Valencia, Spain. To assess the prevalence of IgG antibodies to pertussis toxin (PT) in children, adolescents and adults. METHODS: Prospective study conducted at paediatric primary care centres. All persons < or =15 years in age presented with persistent cough were enrolled. Parents completed a brief questionnaire and immunization history was obtained from paediatrician records. A blood sample was obtained, for determination of IgG antibodies to Bordetella pertussis toxin (PT) by an ELISA method. A study confirmed-case was the presence of two conditions: (1) cough illness of > or =14 days duration; and (2) ELISA absorbance value of IgG to PT > or =2. Two subjects per clinical-case (same centre and range of age) and parents were asked to participate in the prevalence study. RESULTS: Sixty-one children < or =15 years in age presented with symptoms leading to a clinical diagnosis of pertussis were detected. Serological evidence of recent pertussis was found in five of these patients (incidence of 46.0/100,000 persons < or =15 years in age). Prevalence of antibodies to B. pertussis (> or =0.3) in children < or =15 years in age and adults was 39 and 33%, respectively. Only a minority of children, adolescents and adults had absorbance values indicative of immunity (> or =1). CONCLUSIONS: These incidence and seroprevalence results show that despite high immunization rates in infancy, B. pertussis is circulating in Spain.

Adolescent↗

Generation of ROS in response to CCK-8 stimulation in mouse pancreatic acinar cells.

In the present study we have studied the changes in the intracellular reduction-oxidation state in mouse pancreatic acinar cells following stimulation with cholecystokinin octapeptide (CCK-8) and its dependence on Ca2+ mobilization. In our investigations cytosolic Ca2+ concentration and reactive oxygen species (ROS) production were determined by loading of cells with fura-2 and CM-H2DCF-DA, respectively. Changes in these parameters were determined by following changes in fluorescence in the cuvette of a spectrofluorimeter. The results show that stimulation of cells with CCK-8 and/or the sarco-endoplasmic reticulum Ca2+ pump inhibitor, thapsigargin (Tps), both induced changes in cytosolic free Ca2+ concentration and led to an increase in fluorescence of CM-H2DCF-DA, reflecting an increase in oxidation. In the presence of Tps, addition of CCK-8 did not significantly increase fluorescence compared to that evoked by the SERCA inhibitor. Similar results were obtained in the absence of extracellular Ca2+ and in the presence of EGTA. When the cells were challenged in the presence of the intracellular Ca2+ chelator BAPTA and in the absence of extracellular Ca2+ the responses to both CCK-8 and Tps were reduced although not completely inhibited. The mitochondrial uncoupler carbonyl cyanide p-trifluoromethoxy-phenylhydrazone and the inhibitor of the electron transport chain, antimycin, evoked a marked increase in CM-H2DCF-DA fluorescence and completely inhibited CCK-8 and Tps-evoked responses, indicating that ROS are generated in the mitochondria. In summary, stimulation of mouse pancreatic acinar cells with CCK-8 leads to generation of ROS, and this effect may be derived from Ca2+ mobilization from intracellular stores and involves mitochondrial metabolism.

Journal Article↗