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M C Rubio

Publications and source records attributed to M C Rubio.

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

Lack of sex-related differences in the prevention by baclofen of the morphine withdrawal syndrome in mice.

In previous studies we have demonstrated a possible interaction between the GABAergic and opioid systems involved in the antinociceptive effect of the GABA(B) agonist, baclofen (BAC). On the other hand, sex differences have been observed for the antinociceptive effect of morphine (MOR). In the present study, we analyzed sex-related differences in the MOR abstinence syndrome and its prevention with BAC. Prepubertal male and female Swiss-Webster albino mice (27-33 g) were rendered dependent by intraperitoneal (i.p.) injection of MOR (2, 4 and 8 mg/kg), twice daily for 9 days. On the tenth day the dependent animals were divided into two groups: one received naloxone (NAL) (6 mg/kg, i.p.) 60 min after the last dose of MOR, to precipitate the abstinence syndrome; the other group received BAC (2 mg/kg, i.p.) followed by NAL (6 mg/kg, i.p.), injected 30 and 60 min after the last dose of MOR, respectively. Behavioral signs were recorded in the open field for 30 min. Although there were sex differences in the MOR withdrawal syndrome, we found a lack of sex differences in the prevention of the MOR abstinence syndrome by BAC.

Analgesics, Opioid↗
PubMed2000

Effects of clenbuterol treatment on the relaxant response in rat uterus.

Prolonged treatment with the beta(2)-adrenergic agonist clenbuterol (0.25 mg kg(-1) s.c. once daily for 10 days) produced a reduction of the relaxant response and cAMP production mediated by stimulation of beta-adrenoceptors in oestrogen-treated rat uterus. Substantial decreases in the relaxant effect of isoproterenol is observed in uterine rings precontracted with 50 mM KCl from clenbuterol-treated rats. The recovery of the relaxant response was also studied and significant differences were seen between acute and prolonged treatment with clenbuterol (P<0.05 vs control). In contrast the relaxant effect of forskolin and 3-isobutyl-1-methylxanthine was similar in untreated or treated rats. Sodium fluoride also showed a relaxant response which was not affected by the treatment with clenbuterol. The radioligand studies showed a reduction in the number of beta-adrenoreceptors after acute and prolonged treatment with clenbuterol in rat uterus. These results suggest that prolonged treatment with clenbuterol caused a desensitization of the relaxant uterine response through beta(2)-adrenoceptors and also showed differences in the recovery of the relaxant response depending on the duration of treatment.

Adrenergic beta-Agonists↗
PubMed2000

Astrovirus infection among children with gastroenteritis in the city of Zaragoza, Spain.

The incidence of astrovirus infection in children less than 10 years of age with gastroenteritis in the city of Zaragoza, Spain, was analysed during a 12-month period. A total of 718 stool samples obtained from 534 children were examined. In 401 samples no routinely searched for pathogenic organism was detected; these specimens were then tested for the presence of astrovirus antigens. Astrovirus was detected in the samples of 15 (5.5%) patients, a detection rate similar to that recognised for Yersinia enterocolitica and Cryptosporidium spp. All children with confirmed astrovirus infection had diarrhoea (median duration, 9 days), 11 experienced loss of appetite, 5 vomiting, and 4 fever. The incidence of astrovirus infection reported here indicates that Spanish children suffering from gastroenteritis should be routinely screened for the presence of astrovirus.

Astroviridae Infections↗
PubMed2000

Glutathione and homoglutathione synthetases of legume nodules. Cloning, expression, and subcellular localization.

The thiol tripeptides glutathione (GSH) and homoglutathione (hGSH) are very abundant in legume root nodules and their synthesis is catalyzed by the enzymes gamma-glutamylcysteine synthetase (gammaECS), GSH synthetase (GSHS), and hGSH synthetase (hGSHS). As an essential step to elucidate the role of thiols in N(2) fixation we have isolated cDNAs encoding the three enzymes and have quantified the transcripts in nodules. Assay of enzyme activities in highly purified nodule organelles revealed that gammaECS is localized in the plastids, hGSHS in the cytosol, and GSHS in the cytosol and mitochondria. These results are consistent with sequence analyses. Subcellular fractionation of nodules also showed that bacteroids contain high thiol concentrations and high specific gammaECS and GSHS activities. Results emphasize the role of nodule plastids in antioxidant protection and in control of thiol synthesis, and suggest that plastids may be important in the stress response of nodules. Overall, our results provide further evidence that thiol synthesis is critical for nodule functioning.

Amino Acid Sequence↗
PubMed2000

In vitro activity of cefepime and cefotaxime compared to six other agents against 350 penicillin-susceptible and penicillin-resistant Streptococcus pneumoniae.

From January 1996 to December 1997, we evaluated the in vitro activity of 8 antimicrobials (penicillin, amoxycillin, amoxycillin/clavulanate, cefuroxime, ceftazidime, cefepime, cefotaxime, and imipenem) against 350 Streptococcus pneumoniae clinical isolates collected from two hospitals. Imipenem, cefepime and cefotaxime were the most active antibiotics against penicillin-intermediate (PI) and highly penicillin-resistant (PR) S. pneumoniae with MICs 2- to 8-fold lower than penicillin. Against PI and PR pneumococci amoxycillin and amoxycillin/clavulanate were 2-times less active than cefepime and cefotaxime, while cefuroxime was 4-8-times less active. The majority of strains of serotypes 6B, 23F, 14, 9 and 19 were penicillin-resistant, both intermediate (68%) and highly resistant (32%).

Anti-Bacterial Agents↗
PubMed2000

[Study of macrolide-resistant genes in group C and G streptococci].

In the present study we investigated the macrolide-lincosamide-streptogramin B (MLSB) resistance in 47 clinical isolates of group C beta-hemolytic streptococci and 17 group G streptococci. Resistance to erythromycin was found in 31.6%; and 47%, respectively. On the basis of the erythromycin-clindamycin double-disk test, all strains were assigned to the MLSB phenotype. None of the strains were of the M phenotype. The distribution of the erythromycin-resistant genes were studied by dot blot hybridization and PCR. Resistance to erythromycin was due to the presence of mefA, ermB and ermTR genes. The ermTR gene was predominant among the group C and G streptococci (90% of the strains). Different mechanisms of erythromycin resistance predominate in group C and G streptococci than in Streptococcus pyogenes where there is an association between erythromycin resistance and active-efflux mechanism. Two of the strains harbored more than one erythromycin-resistant gene.

Anti-Bacterial Agents↗
PubMed2000

[Pharmacokinetic variability of oxcarbazepine in epileptic patients].

The aim of this study was to analyze the population pharmacokinetics of oxcarbazepine (OCBZ) measuring the serum level of its active metabolite, monohydroxylated oxcarbazepine (MHD). We studied a group of patients with symptomatic and cryptogenic epilepsy treated with OCBZ monotherapy orally, at least for 3 weeks. The mean doses, age and weight of the patients were 17.9 +/- 7.8 mg/kg/day, 35.6 +/- 16.4 years and 70.3 +/- 19.2 kg, respectively. Blood samples were taken before the first morning dose of OCBZ and MHD levels were determined by HPLC. A linear relationship was found between OCBZ dose and MHD serum level (r = 0.844, p < 0.001). The MHD serum concentration (mg/l) can be predicted as 0.85 x OCBZ dose (mg/kg). There was a significant correlation between observed and predicted MHD concentrations for each patient. The mean MHD clearance (Cl/F) calculated was 4.05 +/- 1.69 l/h, with a coefficient variation of 41%. It was independent of dose, age and weight and followed a non normal distribution. The half-life of MHD was 10.50 +/- 3.17 hours. The influence of other antiepileptic drugs on MHD pharmacokinetics was analyzed by comparing the Cl/F medians from groups of patients receiving concomitant drugs with OCBZ monotherapy group where no significant differences were found. The results can be used to estimate a priori OCBZ doses, in order to individualize the treatment.

Adolescent↗
PubMed1999

[3H]Tyramine uptake by rat liver slices.

Rat liver slices were employed as experimental model to characterise the system involved in the transport process which participates in liver tyramine uptake. The uptake of 0.4 micromol l-1of [3H]tyramine by rat liver slices was linear from 5 min up to the end of incubation. At 15 min the uptake was 4.58+/-0.18 pmol mg-1protein. The accumulation of [3H]tyramine was sensitive to temperature (69. 3+/-4.0% inhibition at 0 degrees C, P<0.001), to sodium omission replaced by 150 mmol l-1Tris or 110 mmol l-1Tris+40 mmol l-1choline (27.6+/-6.0%, P<0.01, and 24.6+/-3.8% inhibition, P<0.01, respectively), and the inhibition of Na+-K+-adenosine triphosphatase by 150 micromol l-1ouabain (20.4+/-2.6% decrease, P<0.01). Uptake of [3H]tyramine was cocaine- (10 micromol l-1) and desipramine- (1 micromol l-1) dependent (32.2+/-6.4%, P<0.05, and 31.6+/-4.0% inhibition, P<0.05, respectively). Uptake of [3H]tyramine in rat liver slices was not modified by 30 micromol l-1isoprenaline, 30 micromol l-1corticosterone, 30 micromol l-1normetanephrine and noradrenaline up to 4 micrometers at higher noradrenaline concentrations tyramine transport was diminished (P<0.05). Results achieved by incubation with increasing tyramine concentrations indicate that at the micromolar level hepatic uptake occurs by a combined passive diffusion and transport-mediated mechanism, whereas at greater tyramine concentrations passive transport predominates. These results suggest that both simple diffusion and a transport-mediated mechanism are involved in this uptake from hepatocytes, which presents features similar to those described for type 1 non-neuronal uptake systems.

Adrenal Cortex Hormones↗
PubMed1999

Stress-induced legume root nodule senescence. Physiological, biochemical, and structural alterations.

Nitrate-fed and dark-stressed bean (Phaseolus vulgaris) and pea (Pisum sativum) plants were used to study nodule senescence. In bean, 1 d of nitrate treatment caused a partially reversible decline in nitrogenase activity and an increase in O(2) diffusion resistance, but minimal changes in carbon metabolites, antioxidants, and other biochemical parameters, indicating that the initial decrease in nitrogenase activity was due to O(2) limitation. In pea, 1 d of dark treatment led to a 96% decline in nitrogenase activity and sucrose, indicating sugar deprivation as the primary cause of activity loss. In later stages of senescence (4 d of nitrate or 2-4 d of dark treatment), nodules showed accumulation of oxidized proteins and general ultrastructural deterioration. The major thiol tripeptides of untreated nodules were homoglutathione (72%) in bean and glutathione (89%) in pea. These predominant thiols declined by approximately 93% after 4 d of nitrate or dark treatment, but the loss of thiol content can be only ascribed in part to limited synthesis by gamma-glutamylcysteinyl, homoglutathione, and glutathione synthetases. Ascorbate peroxidase was immunolocalized primarily in the infected and parenchyma (inner cortex) nodule cells, with large decreases in senescent tissue. Ferritin was almost undetectable in untreated bean nodules, but accumulated in the plastids and amyloplasts of uninfected interstitial and parenchyma cells following 2 or 4 d of nitrate treatment, probably as a response to oxidative stress.

Antioxidants↗
PubMed1999

Glutathione and homoglutathione synthesis in legume root nodules.

High-performance liquid chromatography (HPLC) with fluorescence detection was used to study thiol metabolism in legume nodules. Glutathione (GSH) was the major non-protein thiol in all indeterminate nodules examined, as well as in the determinate nodules of cowpea (Vigna unguiculata), whereas homoglutathione (hGSH) predominated in soybean (Glycine max), bean (Phaseolus vulgaris), and mungbean (Vigna radiata) nodules. All nodules had greater thiol concentrations than the leaves and roots of the same plants because of active thiol synthesis in nodule tissue. The correlation between thiol tripeptides and the activities of glutathione synthetase (GSHS) and homoglutathione synthetase (hGSHS) in the nodules of eight legumes, and the contrasting thiol contents and activities in alfalfa (Medicago sativa) leaves (98% hGSH, 100% hGSHS) and nodules (72% GSH, 80% GSHS) indicated that the distribution of GSH and hGSH is determined by specific synthetases. Thiol contents and synthesis decreased with both natural and induced nodule senescence, and were also reduced in the senescent zone of indeterminate nodules. Thiols and GSHS were especially abundant in the meristematic and infected zones of pea (Pisum sativum) nodules. Thiols and gamma-glutamylcysteinyl synthetase were also more abundant in the infected zone of bean nodules, but hGSHS was predominant in the cortex. Isolation of full-length cDNA sequences coding for gamma-glutamylcysteinyl synthetase from legume nodules revealed that they are highly homologous to those from other higher plants.

Amino Acid Sequence↗
PubMed1999

Susceptibility of penicillin-resistant and penicillin-susceptible Streptococcus pneumoniae to newer antimicrobial agents.

Agar dilution minimum inhibitory concentration (MIC) methodology, according to NCCLS guidelines, was used to test the activity of three glycopeptides (LY 333328 [LY], vancomycin [VAN], and teicoplanin [TEI]), four fluoroquinolones (trovafloxacin [TRO], BAY 12-8039 [BAY], ciprofloxacin [CIP], and ofloxacin [OFL]), five macrolide-lincosamide-streptogramin antibiotics (erythromycin [ERY], azithromycin [AZI], miocamycin [MOM], clindamycin CLN], and quinupristin-dalfopristin [SYN] against 126 Streptococcus pneumoniae strains, isolated in Lozano Blesa Hospital of Zaragoza (Spain). MIC50/MIC90 (microg/ml) values for penicillin-susceptible (PS), penicillin-intermediate (PI) and penicillin-resistant (PR) strains show an excellent antipneumococcal activity of LY 333326--a new glycopeptide, for the fluoroquinolones trovafloxacin and moxifloxacin [BAY 12-8039], and for quinupristin/dalfopristin, regardless of the resistance phenotype of the strains.

Anti-Bacterial Agents↗
PubMed1998

Use of a selective medium and a membrane filter method for isolation of Campylobacter species from Spanish paediatric patients.

A study was conducted to assess the value of a combination of two culture methods for isolation of Campylobacter spp. from Spanish children. Seven hundred twenty-nine diarrhoeal stool specimens from 599 patients were examined for Campylobacter spp. by culturing them on charcoal cefoperazone deoxycholate agar and on blood agar with a membrane filter. One hundred sixteen Campylobacter strains were isolated from a total of 108 specimens; 75 (64.6%) were Campylobacter jejuni, 32 (27.5%) were Campylobacter coli, 8 (6.8%) were non-typeable, and one (0.9%) was Campylobacter upsaliensis. Campylobacters were isolated from 99 positive samples using charcoal cefoperazone deoxycholate agar alone. The filtration technique alone yielded only 86 positive samples. Seven specimens yielded different Campylobacter spp. with different media. The only catalase-negative strain was recovered using the filter method. The combination of the selective medium with the filter method increased the isolation rate of Campylobacter strains by 14.1%. Isolation rates of campylobacters using the filter method were similar to those reported in European studies, in which a similar frequency of Campylobacter upsaliensis was observed. The addition of a filter method for routine laboratory isolation of campylobacters should be considered in selected age groups (in children < 10 years of age) or in areas where catalase-negative or weakly-positive Campylobacter strains may be of epidemiological significance.

Adolescent↗
PubMed1998

Fuchsin fluorescence and autofluorescence in Cryptosporidium, Isospora and Cyclospora oocysts.

Cryptosporidium parvum and Isospora belli oocysts stained with carbol-fuchsin, as in a modified Ziehl Neelsen technique, fluoresce bright red under green light (546nm). Cryptosporidium oocysts tend to fluoresce more brightly the less intensely stained they appear under transmitted light; this is not the case with Isospora. Fuchsin-stained Cyclospora cayetanensis oocysts fluoresce rather dimly, but those not taking the dye retain their typical autofluorescence. Cryptosporidium and Isospora oocysts are also autofluorescent, appearing violet under u.v. light (365 nm), and green under violet (405 nm) and blue-violet light (436 nm). Their autofluorescence does not survive the staining procedure.

Animals↗
PubMed1998

Lack of tolerance to the anxiolytic effect of diazepam and pentobarbital following chronic administration in perinatally undernourished rats.

Adult female rats, undernourished at perinatal age, were evaluated for anxiolytic action in the plus-maze test after acute and chronic administration of diazepam (DZP) and pentobarbital (PTB). Deprived (D) rats chronically treated with vehicle showed an increased anxiety as compared with control (C) animals. A single intraperitoneal (i.p.) administration of DZP (1 mg/kg) or PTB (7.5 mg/kg) produced similar anticonflict effect in both C and D rats. Tolerance to the anxiolytic effect of DZP and PBT developed in C rats after a 15-day administration schedule, whereas no tolerance was observed in D animals. Drug disposition was not altered after chronic treatment either in C or in D rats. Gamma-aminobutyric acid (GABA)-mediated chloride uptake in microsacs of cerebral cortex of naive D rats was decreased as compared with naive C rats. After chronic DZP administration (1 mg/kg/day i.p. for 15 days), GABA-mediated 36Cl- influx in brain cortex microsacs of C rats did not change; however, GABA efficacy was increased in microsacs of D animals. In addition, chronic DZP treatment induced GABA-benzodiazepine uncoupling in brain cortex of C rats, but not in D animals, as assessed by chloride uptake in microsacs. Chronic PTB treatment (7.5 or 30 mg/kg/day i.p. for 15 days) did not modify GABA stimulation or GABA-PTB interaction in cortical microsacs of C or D rats.

Animal Nutritional Physiological Phenomena↗
PubMed1998

Expression of interleukin-1 system mRNA in single blastomeres from human preimplantation embryos.

Gathering knowledge about the molecular events during preimplantation development is one of the most important challenges in in-vitro fertilization (IVF). The interleukin-1 (IL-1) system has been shown to be intimately involved in embryonic implantation. The aim of our study was to detect the major components of the IL-1 system in single blastomeres from human preimplantation embryos and to relate our findings to the further development of the biopsied embryos in vitro. Single blastomeres were removed from morphologically normal embryos obtained from dipronuclear zygotes and examined by reverse transcription (RT)-nested polymerase chain reaction (PCR). Expression of beta-actin (external standard), IL-1beta, IL-1 receptor antagonist (IL-1ra) and IL-1 receptor (IL-1R) type I mRNA were related to embryonic development and IVF outcome. Blastomeres from 12 embryos were examined: beta-actin and IL-1R type I mRNA were detected in all blastomeres (100%) whereas IL-1beta could be detected in only nine of the blastomeres (75%). IL-1ra was expressed in only two (17%) of the blastomeres and those were simultaneously positive for IL-1beta. Both IL-1ra positive embryos were arrested in development before reaching blastocyst stage. Five embryos (three of them IL-1beta mRNA positive and two IL-1beta mRNA negative) were transferred as blastocysts; none of the transfers resulted in a pregnancy. We postulate that embryos expressing IL-1ra mRNA in a detectable amount appear more likely to be arrested in early developmental stages.

Base Sequence↗
PubMed1998

The molecular epidemiology of tuberculosis in Zaragoza, Spain: a retrospective epidemiological study in 1993.

SETTING: The incidence of tuberculosis (TB) in Spain is one of the highest in Europe. In Zaragoza region the incidence rate of tuberculosis and the acquired immune deficiency syndrome (AIDS) are close to the national average. OBJECTIVE: To better define the molecular epidemiology of tuberculosis in an area of Europe where this has not been previously studied. DESIGN: A retrospective epidemiological study on tuberculosis was conducted in Zaragoza, a region of Spain, in 1993. The study population consisted of 226 patients from whom positive culture and complete clinical and demographic data were available. Mycobacterium tuberculosis strains were typed by standard restriction fragment length polymorphism (RFLP). A cluster was defined as two or more isolates with identical RFLP patterns when five or more copies of IS6110 are present. The 137 non-clustered patients were compared with the 89 clustered patients and studied by using univariate analysis. RESULTS: Thirty-nine percent of the patients were clustered, suggesting possible recent transmission. Infection with drug-resistant M. tuberculosis was associated with a decreased risk of being in a cluster. The strains isolated from human immunodeficiency virus (HIV)-positive patients were not associated with clustering. We found that immigration was not a major determinant in the total number of TB cases. CONCLUSION: Immigration, HIV and drug resistance were not associated with recent transmission. More than 50% of the clusters contained two or three patients, indicating that small outbreaks were responsible for most of the tuberculosis cases. Our RFLP typing results indicate that a TB control programme should be implemented in Spain in order to lower transmission of TB.

AIDS-Related Opportunistic Infections↗