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Biomedical subjects

A Serrano

Publications and source records attributed to A Serrano.

At least 19 recordsLinked to original sources
PubMed1992

Purification, characterization and function of dihydrolipoamide dehydrogenase from the cyanobacterium Anabaena sp. strain P.C.C. 7119.

A dihydrolipoamide dehydrogenase (dihydrolipoamide: NAD+ oxidoreductase, EC 1.8.1.4) (DLD) has been found in the soluble fraction of cells of both unicellular (Synechococcus sp. strain P.C.C. 6301) and filamentous (Calothrix sp. strain P.C.C. 7601 and Anabaena sp. strain P.C.C. 7119) cyanobacteria. DLD from Anabaena sp. was purified 3000-fold to electrophoretic homogeneity. The purified enzyme exhibited a specific activity of 190 units/mg and was characterized as a dimeric FAD-containing protein with a native molecular mass of 104 kDa, a Stokes' radius of 4.28 nm and a very acidic pI value of about 3.7. As is the case with the same enzyme from other sources, cyanobacterial DLD showed specificity for NADH and lipoamide, or lipoic acid, as substrates. Nevertheless, the strong acidic character of the Anabaena DLD is a distinctive feature with respect to the same enzyme from other organisms. The presence of essential thiol groups was suggested by the inactivation produced by thiol-group-reactive reagents and heavy-metal ions, with lipoamide, but not NAD+, behaving as a protective agent. The function and physiological significance of Anabaena DLD are discussed in relation to the fact that 2-oxoacid dehydrogenase complexes have not been detected so far in filamentous cyanobacteria. Glycine decarboxylase activity, which might be involved in photorespiratory metabolism, has been found, however, in cell extracts of Anabaena sp. strain P.C.C. 7119 as the present study demonstrates.

Amino Acid Oxidoreductases↗
PubMed1992

Neurotoxic effects of the intrastriatal injection of spermine and spermidine: lack of involvement of NMDA receptors.

The injection into the rat striatum of the polyamines spermine and spermidine (30-300 nmol) produced, 1 week after injection, a dose related loss of the neuronal markers glutamate decarboxylase and choline acetyltransferase and a decrease in the density of N-methyl-D-aspartate (NMDA) receptors (as labelled with [3H]TCP). In parallel, an increase in peripheral type benzodiazepine (p) binding site density (a marker of the associated glial reaction and macrophage invasion) was observed. Intrastriatal injection of putrescine (300 nmol) did not significantly alter any of these markers. The effect of spermine on these neuronal and glial markers was maximal 3 days after injection, and tended towards control levels at 16 days post injection. The neurotoxic effects of spermine were confirmed by histological analysis demonstrating a massive neuronal loss around the injection site and an accumulation of astrocytes and phagocytes. The neurotoxic effects of spermine (250 nmol) were not antagonised by the previous administration of the NMDA receptor antagonist MK-801 (10 mg/kg, i.p.). Thus polyamine neurotoxicity in vivo does not seem to involve NMDA receptor activation, although it may possibly be related to the multiple effects of these compounds on diverse calcium channels and processes regulating calcium homoeostasis.

Animals↗
PubMed1992

[Consistency of the histologic diagnosis of Lauren's classification of gastric cancer].

BACKGROUND: Lauren's classification of gastric cancer is usually followed in epidemiological studies thus requiring evaluation of its reproducibility. This classification defines 2 principal histological types: intestinal and diffuse with different proportions in high and low risk areas possibly being associated to different causal factors. METHODS: The concordance diagnosis in an aleatory sample of 81 gastric carcinomas stratified according to the participation of 14 hospitals in an epidemiological study of 354 cases and 354 controls was analyzed. The initial diagnosis carried out was compared by more than 20 pathologists with the reclassification diagnosis by consensus of 2 pathologists by the proportion of agreement or concordance observed in the kappa index. Keeping the final reclassification by consensus as a reference, sensitivity, specificity and predictive values were also calculated. RESULTS: The proportion of concordance observed was of 78% for the intestinal and 90% for the diffuse with a kappa index of 0.55 and 0.74, respectively. Sensitivity for the intestinal type was of 88% and for the diffuse 81% with specificity being of 67% in the intestinal and 93% in the diffuse. CONCLUSIONS: Subjectivity in the interpretation of certain parameters necessary for histological diagnosis may be reduced by the elaboration of protocols in which the principal histological criteria to follow are detailed. Nonetheless, the distinction made between the two principal types, intestinal and diffuse, is valid enough to be used in multicenter epidemiological studies and in comparative studies.

Case-Control Studies↗
PubMed1992

Direct-acting mutagenic activity in white, rosé, and red wines with the Ara test of Salmonella typhimurium.

Thirty-two commercially produced white, rosé, and red wines from Spain were assayed for genotoxicity. The Ara forward mutagenicity assay with Salmonella typhimurium served as the test system. All the wines were mutagenic in the absence of mammalian microsomal activation (S9 mix) and/or glycosidase activities with the exception of one rosé wine which gave a clear dose-response relationship, although its mutagenic potency was considered statistically nonsignificant. The mutagenic activity covered nearly a 30-fold range. Compared to white and rosé wines, red wines showed the highest levels of mutagenicity; this wine type included four "very potent" (greater than 3,000 AraR mutants/ml) mutagenic wines. The level of wine mutagenicity did not correlate with either the region or the year of production (vintage). Individual winery methods are suggested as primarily responsible for variations in mutagenic activity. The present study with the Ara test supports the possibility that wine components other than the flavonols quercetin and rutin are the major putative mutagens: (1) white wines, as well as rosé or red wines, were detected as being mutagenic; (2) in no case was activation required for the detection of mutagenicity; (3) mutagen(s) were detected mainly (red wine) when not exclusively (white and rosé wine) in the polar fraction from XAD-2 chromatography. The high sensitivity of the Ara test has allowed the screening of the mutagenicity of a variety of wines with no previous process of extraction or concentration. The comparison of the mutagenic activity of the entire complex mixture to that of its lyophilized residue has revealed a positive synergistic role for ethanol in the mutagenicity of certain wines. Finally, this work suggests that the Ara test is a useful tool for mutagenicity screening in wines. Thus, this test might play an important role in elucidating the genotoxic mechanism of action of alcoholic beverages, and for studying optional production methods to decrease the mutagenicity of commercial wines.

Arabinose↗
PubMed1992

The infundibular interrelationships and the ventriculoarterial connection in double outlet right ventricle. Clinical and surgical implications.

Fifty specimens of double outlet right ventricle were studied. The insertion of the outlet (infundibular) septum determines two types of infundibular interrelationships. In the first type, with anterior and posterior infundibulums, the outlet septum is inserted to the anterior limb of the septomarginal trabeculation; the posterior infundibulum is related with the atrioventricular orifices and the interventricular septum forms exclusively one of the walls of the posterior infundibulum. Therefore, the artery connected with the posterior infundibulum may be related with a subarterial ventricular septal defect. Of our material, 35 cases (70% of 50) had anterior and posterior infundibulums and, in 32, the aorta was connected with the posterior infundibulum (91.4% of 35). The ventricular septal defect was subaortic in 26 cases (81.2% of 32). In the second type, with side-by-side infundibulums, the outlet septum is inserted in to the ventriculo-infundibular fold in the proximity of the posterior limb of the septomarginal trabeculation. Both infundibulums are related with the atrioventricular orifices and the interventricular septum forms exclusively one of the walls of the medial infundibulum. Therefore, the artery connected with the medial infundibulum has the possibility of being related with a subarterial ventricular septal defect. Of our material, 13 cases (26% of 50) had side-by-side infundibulums. In all of these (100% of 13), the pulmonary trunk was connected with the medial infundibulum and the ventricular septal defect was subpulmonary in 12 cases (92.3% of 13). There were two cases (4% of 50) with a doubly committed ventricular septal defect. The insertion of the outlet septum permits one to determine the infundibular interrelationships, information which cannot be attained by taking into account the relationship of the great arteries with each other. Once the infundibular interrelationship is established, one must determine if the aorta is connected with the posterior or with the medial infundibulum, since, depending on the anatomical constitution of these infundibulums, there is the possibility of a ventricular septal defect being related with this artery. This information is indispensable before attempting the surgical correction of the double outlet right ventricle and it may be obtained by echocardiography or by angiocardiography.

Adult↗
PubMed1992

Study on the mutagenicity of brandy with the Ara test.

The forward mutation assay to L-arabinose resistance (Ara test) in Salmonella typhimurium was used to demonstrate that evaporated residues of brandy had direct-acting mutagenic activity. The mutagenicity covered a 100-fold range, from 13482 to 127 AraR induced mutants/ml brandy equivalent. Rat liver S9 mix suppressed the mutagenic activity of brandy in the Ara test. The inactivating capacity was independent of microsomal monoxygenase enzymes and appeared to be mediated through a heat stable component of the S9 fraction. Catalase was identified as the putative S9 component responsible for its inactivating capacity. The implication of reactive oxygen species in the direct-acting mutagenicity of brandy was supported by the higher sensitivity of Escherichia coli bacterial strains deficient in two major cellular antioxidant defense (glutathione and/or catalase) compared to their parental wild-type. Phenolic compounds of a polar nature could be responsible for the mutagenicity through the production of reactive oxygen intermediates. Non-matured beverages (gin and non-matured rum) were non-mutagenic. It is conceivable that mutagenic phenolics might be extracted from the wood during maturation in the barrel. Autoxidation of phenolic compounds could be a common mechanism in the mutagenicity of complex mixtures of plant origin.

Alcoholic Beverages↗
PubMed1992

[Endourologic treatment of calyceal diverticulum complicated with lithiasis].

Presentation of 9 cases of calyceal diverticulum symptomatic lithiasis, 6 of which have been treated up to the present time. Of the remaining 3, one patients, in spite of its evolutive character (increased cavity) and moderate pain, prefers to abstain from therapeutic therapy, but undergoes follow-up controls every 6 months; the other 2 cases are waiting endourological treatment. Out of 6 patients who underwent surgery, two cases, who had previously experienced shockwave extracorporeal lithotripsy (SWEL), were advised to have endourological procedures due to persistence of pain and gallstones debris.

Catheterization↗
PubMed1992

[A cellular proliferation study in patients with colorectal cancer, solitary, synchronous and with polyps].

Colonic carcinogenesis is probably related to a disturbance in cell proliferation of the colonic mucosa. The present study was designed to determine whether patients with adenomatous polyps of the colon, which have a tendency to develop synchronous malignancies of the colon, have any disturbance in mucosal cell proliferation. Using flow cytometry the proliferative index, and the S and G2M phases of normal mucosa and tumoral tissue of patients with colorectal cancer (synchronous, alone, or associated with adenomatous polyps) were studied. No differences were found between the there groups of study at the level of proliferation pattern of normal mucosa. Our findings do not support the development of synchronous or metachronous colon cancer in patients with polyps on the basis of different patterns of cell proliferation.

Aged↗
PubMed1991

Differential regulation by trophic conditions of phosphorylating and non-phosphorylating NADP(+)-dependent glyceraldehyde-3-phosphate dehydrogenases in Chlorella fusca.

The two NADP(+)-dependent glyceraldehyde-3-phosphate dehydrogenases present in the green alga Chlorella fusca, namely, the phosphorylating (chloroplastic) enzyme and the non-phosphorylating (cytosolic) enzyme, are differently affected by the trophic conditions prevailing in the cell cultures. The addition of metabolizable sugars to cell cultures growing in the light promotes a marked decrease of the phosphorylating enzyme activity down to a barely detectable cellular level. In contrast, the cellular level of the non-phosphorylating enzyme is even enhanced in the presence of such sugars. These effects are not observed, however, with a number of non-assimilable sugar analogs. After sugar removal, a recovery of the phosphorylating activity--in a process which is inhibited by cycloheximide but not by lincomycin--is observed in illuminated cells but not in darkness, thus indicating a light-dependent nuclear synthesis of the chloroplastic enzyme. It seems therefore that the two dehydrogenases are adaptative enzymes subject to differential regulation by nutritional conditions.

Carbohydrates↗
PubMed1991

Effect of the putative 5-HT1A receptor antagonist NAN-190 on rat brain serotonergic transmission.

Based on the fact that 1-(2-methoxyphenyl)-4(4-(2-phtalimido)butyl)piperazine (NAN-190), a high-affinity ligand for 5-HT1A and alpha 1-adrenoceptors, antagonizes the behavioural effects of the 5-HT1A receptor agonist 8-OH-DPAT (8-hydroxy-2-(di-n-propylamino)tetralin), it has been suggested that this drug behaves as a 5-HT1A receptor antagonist. In the present study we examined the effects of this putative 5-HT1A receptor antagonist on rat brain serotonergic neurotransmission. In hippocampal slices of immature rats, NAN-190 but not prazosin potently antagonized (IC50 = 29 nM) the inhibitory effect of 8-OH-DPAT (1 microM) on carbachol-stimulated phosphoinositide turnover but (up to 1 microM) failed to alter the carbachol response. Similarly, NAN-190 (0.1 microM) almost totally prevented the inhibition by 8-OH-DPAT (1 microM) of forskolin-stimulated adenylate cyclase activity in adult rat hippocampal slices but, per se, was without effect on the forskolin response. These results indicate that NAN-190 is a potent antagonist at postsynaptic 5-HT1A receptors in vitro. However, NAN-190 also potently antagonized (IC50 = 0.16 nM) the stimulation by norepinephrine of phosphoinositide turnover in rat cortical slices. In this respect NAN-190 was a 250-fold more potent antagonist than prazosin (IC50 = 49 nM). Thus, in addition to its 5-HT1A receptor antagonist properties, NAN-190 has potent alpha 1-adrenoceptor blocking properties.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

The effects of N-methyl-D-aspartate and kainate lesions of the rat striatum on striatal ornithine decarboxylase activity and polyamine levels.

The intrastriatal injection of N-methyl-D-aspartate (NMDA) (250 nmol) produced a delayed and marked increase in striatal ornithine decarboxylase (ODC) activity and putrescine levels which peaked 6-15 h following the injection of NMDA. Striatal ODC activity subsequently returned to normal values while putrescine levels remained significantly elevated for up to 4 days following the lesion. NMDA produced an early and progressive decline in striatal spermine and spermidine levels, preceding the increase in ODC activity, with a maximum effect 2 h following injection. Spermidine levels returned to normal 6 h post-NMDA infusion, and subsequently increased to above normal levels 36 h and 4 days after the infusion of NMDA. This late increase in striatal spermidine levels paralleled an increase in the binding of the glial cell/macrophage marker [3H]PK 11195. Spermine levels tended to return to normal values 6 h after the injection of NMDA but may be further depressed at later intervals (15 h to 4 days). The intrastriatal injection of saline also resulted in a delayed increase in striatal ODC activity and putrescine levels, but these changes were minor compared to those produced by NMDA. Intrastriatal saline injection provoked no consistent change in striatal spermine or spermidine levels. The changes in polyamine metabolism produced by the intrastriatal injection of kainic acid (4 nmol) were only analysed at 6 and 15 h following injection but were qualitatively similar to those produced by NMDA although perhaps following a slightly more delayed time-course.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Increase in omega 3 (peripheral type benzodiazepine) binding sites in the rat cortex and striatum after local injection of interleukin-1, tumour necrosis factor-alpha and lipopolysaccharide.

The possible involvement of lymphokines in the glial reaction/proliferation that follows brain injury has been investigated by measuring the density of omega 3 (peripheral type benzodiazepine) binding sites associated to glial cells and macrophages after local injection of lymphokines in the rat cerebral cortex and striatum. omega 3 Site densities were measured either by quantitative autoradiography in brain sections or by conventional binding in membrane using [3H]PK 14105 or [3H]PK 11195 as ligands. Intracortical or intrastriatal infusion of interleukin-1 (10 and 20 units) caused a marked increase in the density of omega 3 sites (+83% and +80%, respectively, when compared to saline-infused animals) around the injection site at 7 days postinjection. There was a good spatial correspondence between the autoradiographic distribution of omega 3 sites and the distribution of reactive astrocytes (as assessed by GFAP immunostaining) or acid phosphatase rich cells (phagocytes). Significant increases in omega 3 site densities were also observed in striatal homogenates 1 week after local administration of tumor necrosis factor-alpha (TNF-alpha). The maximal increase (+80%) was observed after the administration of 3 units, higher and lower doses resulting in smaller increases. Intrastriatal injection of E. coli lipopolysaccharide (LPS), a bacterial endotoxin known to stimulate interleukin-1 and TNF-alpha production by microglial cells in culture, also resulted in significant increases in omega 3 site densities in striatal homogenates (maximal increase, +170% 1 week after the injection of 200 ng).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Tracheal agenesis: an unresolved problem.

A case of tracheal agenesis diagnosed at birth is discussed in which surgical correction was attempted. Both main bronchi were divided and anastomosis of the main right bronchus to the larynx was attempted, after intrapericardial release of the right lung and severing of the lower pulmonary ligament: bronchoplastic reconstruction of the trachea was impossible. We think that tracheal agenesis, a rare cause of respiratory distress in the newborn, has no suitable therapy today. It is justified to attempt surgical correction if any promising device is at hand or if any doubt exists that an uncorrectable situation is present.

Humans↗
PubMed1991

[Doppler analysis of mitral flow in mild to moderate hypertension].

We evaluate by Echo-Doppler the left ventricular relaxation disturbance produced by mild to moderate hypertension. It's a comparative study between 15 healthy and 40 patients with hypertension (diastolic blood pressure between 90-114 mmHg and/or systolic greater than 160 mmHg). Echocardiography was performed in all cases and diameters, thickness, volumes, ejection fraction, mass, transmitral flow by Doppler and cardiac output were evaluated . In hypertensive patients the septal and posterior wall thicknesses were significantly higher (1.39 +/- 0.2 cm vs 1.1 +/- 0.1, p less than 0.001 cm. and 1.26 +/- 0.12 cm vs 0.98 +/- 0.1 cm, p less than 0.001), and also the absolute mass and corrected according to corporal surface (339 +/- 58 g vs 203 +/- 44, p less than 0.001, and 185 +/- 34 g/m2 vs 115 +/- 16, p less than 0.001). In transmitral flow Doppler the higher isovolumetric period and lower diastolic filling in the first 1/3 (71 +/- 19 msec vs 53 +/- 20, p less than 0.05, and 35 +/- 5% vs 52 +/- 4%, p less than 0.001) are indicators of relaxation disturbance. A lower deceleration of early inflow and a higher deceleration time (265 +/- 98 cm/sec2/vs 454 +/- 139, p less than 0.001, and 226 +/- 38 msec vs 156 +/- 15, p less than 0.001) show compliance damage. The atrial filling was significantly higher in hypertensive patients (37 +/- 7% vs 20 +/- 8%, p less than 0.001). The E/A ratio, separate both groups but corrected by the age the signification was rather lower.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Differential responsiveness of the rat dorsal and median raphe 5-HT systems to 5-HT1 receptor agonists and p-chloroamphetamine.

The dorsal and median raphe 5-HT neurons give rise to projections that differ in axon morphology and in vulnerability to certain amphetamine derivatives. The present study was undertaken to determine if these two 5-HT systems possess different functional properties. To this end, we studied the effects of selective 5-HT1A or 5-HT1A/5-HT1B receptor agonists and of p-chloroamphetamine on extracellular levels of indoleamines, as measured by differential pulse voltammetry with extracellular levels of indoleamines, as measured by differential pulse voltammetry with electrochemically pretreated carbon fiber electrodes, in cell body and nerve terminal regions of these subsets of 5-HT neurons in the rat brain. The selective 5-HT1A agonist 8-OH-DPAT produced a gradual decrease in the height of the 300 mV oxidation peak in the dorsal raphe and in the frontal cortex, reaching a maximum of 60% 3 h after the i.v. injection of 30 micrograms/kg. However, the same dose of 8-OH-DPAT was ineffective in the median raphe and in the dentate gyrus that receives its 5-HT innervation exclusively from the median raphe. A higher dose of 8-OH-DPAT (150 micrograms/kg, i.v.) produced a 60% decrease in the height of the 300 mV oxidation peak in the median raphe, whereas only a 20% decrease was obtained in the dentate gyrus. In contrast, the non-selective 5-HT1 agonist RU 24,969 (10 mg/kg, i.p.) caused a 70% reduction of the 300 mV peak height in both the dorsal and median raphe and a 50% decrease in both the frontal cortex and the dentate gyrus. Moreover, although a high dose of 8-OH-DPAT (150 micrograms/kg, i.v.) given alone reduced by 20% the amplitude of the oxidative peak in the dentate gyrus, subsequent administration of RU 24,969 (10 mg/kg, i.p.) caused a further 30% diminution of the oxidative peak height. The greater responsiveness of dorsal as compared to median raphe 5-HT systems to 5-HT1A receptor agonists was confirmed in two further series of experiments. First, the microiontophoretic application of 8-OH-DPAT directly onto 5-HT neurons was three times more potent in suppressing the firing rate of dorsal raphe 5-HT neurons than that of their median raphe congeners. Second, 8-OH-DPAT and buspirone were ten and four times, respectively, more potent in decreasing 5-HT synthesis in the frontal cortex than in the hippocampus.(ABSTRACT TRUNCATED AT 400 WORDS)

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMed1990

Mesocorticolimbic dopaminergic systems and emotional states.

We have used the technique of in vivo voltammetry with carbon fibre electrodes to investigate further the involvement of ascending mesencephalic dopaminergic systems in emotional states in freely moving rats. In Sprague-Dawley rats, forced locomotion caused an increase in extracellular DOPAC levels in the striatum and nucleus accumbens but not in the prefrontal cortex. Immobilization (4 min) or systemic injection of the anxiogenic agent methyl-beta-carboline carboxylate enhanced extracellular DOPAC in both prefrontal cortex and nucleus accumbens but not in striatum whereas tail-pinch provoked a selective increase in this parameter in the nucleus accumbens. These data suggest that mesolimbic and mesocortical dopaminergic systems can be specifically activated by certain kinds of anxiogenic stimuli. To evaluate the relationship between emotional status and the response of mesocortical dopaminergic neurons to stress, we investigated the effects of stressful conditions on dopamine metabolism in the prefrontal cortex of 2 genetically selected lines of rats which differ drastically in their level of emotionality. Introduction of the animals into an unfamiliar environment, application of a high-intensity loud noise or immobilization were associated with an increase in extracellular cortical DOPAC levels in the hypoemotional (RHA) but not in the hyperemotional (RLA) line. These results suggest that the increase in cortical dopamine metabolism induced by stress is not connected to the emotional reaction caused by the aversive nature of the stressor but may reflect activation of cognitive processes in an attempt to cope with the stressor.

Animals↗
PubMed1990

Outer membrane proteins of E. coli in the host-pathogen interaction in urinary tract infection.

Outer membrane protein patterns (Omp) of Escherichia coli obtained directly from the urine of bacteriuric patients without passage on artificial culture media (ACM) were studied by polyacrylamide gel electrophoresis (SDS-PAGE) in an effort to determine whether in vivo conditions of growth affected the expression of these bacterial surface structures. Seventeen strains studied showed two distinct Omp patterns: one protein band appeared at the level of porin proteins (40 kDa) in both patterns, but Omp A protein was at the level of 36 kDa in the first pattern and a new protein was observed at 21.5 kDa in the second pattern suggesting that it is a fragment of Omp A. High molecular weight proteins were also observed in most of the strains and this finding was related to lack of free iron when the same strains were grown under iron restricted conditions in vitro. The same strains grown in pooled urine from normal females showed the first pattern mentioned above. Comparative growth on ACM of urinary strains and E. coli strains isolated from blood, feces and wounds showed an increase in the number of porins expressed (from 1 to 2 or 3, with some variability observed between strains). Differences in osmolality between pooled urine and ACM used, plus in vitro studies varying the osmolality of culture media, showed that osmolality accounted for differences in the number of porins expressed: porin expression decreased in urine the ACM of high osmolality, suggesting that the same phenomena occurred in vivo. It is concluded that host factors including low availability of iron and high osmolality present in the urinary tract influence the expression of several E. coli surface proteins. These proteins may relate to the ability of E. coli to colonize and invade the urinary tract by regulating the physiologic and/or metabolic state of the bacterial cell favoring survival of the organism in a hostile environment. Specific immune responses directed against porins could influence the outcome of this host-parasite interaction.

Bacterial Outer Membrane Proteins↗