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Biomedical subjects

M C Rubio

Publications and source records attributed to M C Rubio.

At least 73 records · Page 4Linked to original sources
PubMed1991

[Epidemiology of shigellosis and colicin typing of Shigella sonnei. A 14-year study].

To study the most important epidemiologic features of shigellosis and the application of colicinotyping as an epidemiologic marker for Shigella sonnei. A total of 44.818 stoll-cultures were performed. We classify, using colicinotyping, 156 Shigella sonnei strains isolated from different patients. The incidence of Shigellosis in our media is low (1.08% of all stool-cultures). It is more frequent in pediatric population and increases on late summer and fall. We had been able to show an increasing incidence, with an hyperendemic situation during a three-years period (1981-1983). Shigella sonnei is the most prevalent species (86% of cases), followed by S. boydii (7.3%) and S. flexneri (5.9%). All S. sonnei strains epidemiologically related showed the same colicinotype. Only two strains were not typable and we identified 9 different colicinotypes, being type 13 (30.8%), type 8 (18.6%), type 6 (17.3%) and type 12 (11.54%) the more frequent types. Colicinotype 8 was the more prevalent between 1978-1979. Type 13 was predominant between 1981 and 1985. During 1987 and 1989, at the same time that incidence had risen, types 6 and 12 were prevalent. The total number of different colicinotypes identified during a single year is never greater than five. Colicinotyping of S. sonnei is a simple typing method that gives enough useful epidemiologic information, discriminative and reproducible. Although there are changes of circulating types incidence and the prevalen colicinotype colud vary from one year to another, during longer periods of time there is a reduced number of alternating colicinotypes, which sets up a situation that could be further classified as endemic.

Adult↗
PubMed1990

Accumulation of 3H-(+/-)-noradrenaline by isolated rat liver cells.

Using hepatocytes isolated by collagenase perfusion, we studied the accumulation of 3H-noradrenaline. Cells incubated during 15 min in the presence of 0.4 mumol/l 3H-noradrenaline (without inhibition of noradrenaline metabolism) accumulated 8.32 +/- 1.77 pmol/10(6) cells (n = 3). The accumulation of 3H-noradrenaline in isolated parenchymal liver cells was sensitive to 10 mumol/l cocaine (inhibition 36.6 +/- 7.9%, n = 3) and 1 mumol/l desipramine (inhibition 27.2 +/- 6.9, n = 3). Accumulation of 3H-noradrenaline was temperature and sodium dependent (inhibition 33.2 +/- 9.4%, n = 9, when Na+ was replaced by Tris+) and was influenced by the inhibition of the membrane Na(+)-K(+)-adenosine triphosphatase (Na(+)-K(+)-ATPase) by 150 mumol/l ouabain (34.7 +/- 6.9% inhibition, n = 3). Accumulation of 3H-noradrenaline in the hepatocytes was not affected by the presence of uptake2 inhibitors, normetanephrine (30 mumol/l) and corticosterone (30 mumol/l), but was reduced by 30 mumol/l isoprenaline (76.3 +/- 5.0% inhibition, n = 6). Thus, the system that takes up and accumulates noradrenaline in the isolated rat liver cells possesses some characteristics of both, uptake1 and uptake2 systems and appears to be different from other extraneuronal cocaine-sensitive systems, such as the one reported for pulmonary endothelial cells.

Animals↗
PubMed1990

Chemical stress and GABAergic central system.

1. The function of the gamma-aminobutyric acid (GABA)ergic system in certain areas of the rat brain was investigated after acute (30 sec) ether stress. 2. GABA endogenous concentrations, uptake of [3H]GABA and the activity of glutamate decarboxylase were measured in different brain areas. 3. After 30 sec of exposure to ether vapour, GABA concentration and total [3H]GABA uptake in the frontal cerebral cortex were increased. In contrast, stress increased GABA concentration in the hypothalamus, but reduced total [3H]GABA uptake. 4. Since the neuronal component of [3H]GABA uptake was increased in the frontal cerebral cortex this might be responsible for the increase in total [3H]GABA uptake. The increase in the endogenous concentration of GABA in the hypothalamus probably resulted from its enhanced synthesis because GAD activation was observed in the hypothalamus after stress. 5. In conclusion, the present study shows that acute ether stress induces rapid and quickly reversible changes in the GABAergic system according to the area of brain. The characteristics of these changes as related to their quick appearance and reversibility might suggest an effect upon neuronal activity due to acute stress exposure.

Animals↗
PubMed1990

Resistance to apramycin in two enterobacterial clinical isolates: detection of a 3-N-acetyltransferase IV.

Considering the possible role of farm animals in the contamination of human consumers by plasmid-mediated apramycin-resistant enterobacteria strains, this type of resistance should be tested more systematically in human isolates. Very recently we isolated in Zaragoza one apramycin-resistant Escheria coli strain obtained from the blood of a hospitalized patient; this clinical isolate produced a plasmid-mediated 3-N-aminoglycoside acetyltransferase IV. We describe also the isolation in Madrid of one multiresistant Klebsiella pneumoniae clinical strain. This isolate harbored a single plasmid and carried determinants for apramycin, gentamicin, tobramycin, hygromycin B, streptomycin, and ampicillin, which could be transferred en bloc to E. coli K-12 J62. Extracts from donor and transconjugant strains carrying pUZ6776 plasmid produce acetyltransferase activity AAC(3)-IV and double phosphotransferase activity (HPH and APH(3'')).

Acetyltransferases↗
PubMed1990

[Evaluation of systolic and diastolic left ventricular function in acute myocardial infarction by aortic echogram].

A noninvasive method for the measurement of the cardiac output and diastolic ventricular function was evaluated by aortic echogram in a group of patients with acute myocardial infarction (AMI). The following parameters were employed: average of initial and late aortic cusp separation (ACS), left ventricular ejection time (EP) and amplitude of aortic posterior wall during ejection (AA). The following formula was used: cardiac output (CO) = (ACS x EP) x 100 + AA x HR. Diastolic ventricular function was evaluated by the left auricle emptying index (LAEI) described by Strunk et al. This last relationship X/OA where X is the movement of the aortic posterior wall (AP) at the first third of passive diastole, and OA is the total aortic movement during the passive diastole. All patients were followed by cardiac output measurements by thermodilution and pulmonary capillary pressure (PCP). Twenty measurements were made in fourteen subjects; for CO a good lineal correlation was found (r = 0.81). As for diastolic ventricular function, LAEI reached a value of 0.49 (+/- 0.23); normal value was 0.82 (p less than 0.01); it was significantly diminished showing the stiffness of the chamber. The utilization of aortic echogram and the analysis of movement of APW result in a non invasive reliable procedure that can be repeated to evaluate the hemodynamic situation in AMI.

Aged↗
PubMed1989

Acute effects of S-adenosyl-L-methionine on catecholaminergic central function.

Catecholaminergic function was studied in rat brain areas after acute administration of S-adenosyl-L-methionine (SAM: 10 mg/kg i.p.). The noradrenaline (NA) concentration increased in the hippocampus and frontal cortex and decreased in the olfactory bulbs between 1 and 2 h after the SAM injection. NA biosynthesis was stimulated in vivo and the concentration of normetanephrine was increased only in the hippocampus. SAM may indirectly affect NA biosynthesis and metabolism. This effect on noradrenergic function might participate in its putative antidepressive action.

Animals↗
PubMed1989

Effects of lovastatin and leupeptin on ceroidogenesis of vitamin E-deficient and -supplemented young rats.

Previous studies in young normal rats have shown that intracerebral administration of the proteinase inhibitor, leupeptin, caused a rapid accumulation of lipofuscin-like pigment in lysosomes of brain cells (Ivy et al., 1984a). On the other hand, we have recently found that the administration of lovastatin, an inhibitor of HMG-CoA reductase, reduced the ceroid-like pigment and dolichol contents in the crushed epididymal fat pad of rats (Porta et al., 1988). In order to study now the possible modulating effects of these enzyme inhibitors on ceroidogenesis associated with vitamin E deficiency, two main groups of weanling Wistar female rats were respectively fed ad libitum a vitamin E-deficient basal diet, or the same diet supplemented with 16 mg% of dl-alpha-tocopherol acetate. The vitamin E-deficient and -supplemented rats were further subdivided and received for 8 weeks their diets alone or with 2, 1, or 0.5 g of lovastatin/kg of diet. Other subgroups were treated with constant peritoneal infusion of 0.5 mg/day of leupeptin by means of osmotic minipumps (Alzet 2002) consecutively implanted at days 15, 30, and 45. Lovastatin treatment to vitamin E-deficient rats was associated with dose-dependent toxicity, resulting in 100%, 75%, and 50% mortality at concentrations of 2, 1, and 0.5 g/kg diet, respectively. This mortality was mainly due to extensive hepatic necrosis. Food intake and growth rates were reduced, while the relative weights of liver, kidneys, spleen, heart and brain, as well as the serum levels of GPT and GOT were significantly increased over the values of the untreated vitamin E-deficient control rats. The volumetric densities of ceroid pigment and the dolichol contents in liver and kidneys were not significantly modified. Lovastatin toxicity was partially prevented by vitamin E supplementation. However, in these supplemented rats, lovastatin treatment did not modify the volumetric densities of hepatic and renal ceroid, although the contents of hepatic and renal dolichol were significantly increased. No correlations could be found between levels of hepatic or renal ceroid and total dolichol content in vitamin E-deficient and supplemented rats. Leupeptin treatment to vitamin E-deficient rats only slightly reduced food intake and growth rates, and did not significantly modify the relative organ weights or the serum levels of cholesterol, GOT and GPT. Although in both vitamin E-deficient and -supplemented rats the leupeptin treatment consistently showed a tendency to increase the volumetric densities of hepatic and renal ceroid pigment, the differences with the control untreated rats were not statistically significant.(ABSTRACT TRUNCATED AT 400 WORDS)

Alanine Transaminase↗
PubMed1989

Acute changes in 5-HT metabolism after S-adenosyl-L-methionine administration.

1. This study investigates S-adenosyl-L-methionine (SAM) (10 mg/kg, i.p.)acute effects upon 5-HT metabolism in rat brain areas. 2. One hour after SAM injection 5-HT biosynthesis was increased in the corpus striatum (55%), the hippocampus (3-fold) (82% 2 hr after SAM injection) and decreased in the olfactory bulbs (34%). 3. 5-HT levels were: (a) increased in the corpus striatum (39%), the hippocampus (44%) and the frontal cortex (27%), and oppositely reduced in the olfactory bulbs (47%) 1 hr after SAM injection; (b) increased in the hippocampus (39%) and reduced in the olfactory bulbs (35%) 1.5 hr after SAM injection; (c) increased in the hippocampus (25%) 2 hr after SAM injection. 4. 5-HIAA levels were reduced in the olfactory bulbs 27% or 21% after 1 hr or 1.5 hr from SAM injection respectively. 5. These area-related changes in 5-HT biosynthesis and metabolism might suggest a possible neurochemical substrate for the antidepressant properties of SAM.

5-Hydroxytryptophan↗
PubMed1989

The susceptibility to amoxycillin/clavulanate of Enterobacteriaceae with plasmid-mediated ampicillin resistance: a twelve-year study of strains in one Spanish hospital.

We studied the antibacterial activity of amoxycillin, clavulanic acid and the combination, against 1210 clinical isolates with plasmid-mediated ampicillin resistance, isolated at the Zaragoza Clinical University Hospital during 12 years. MICs were determined by an agar dilution technique with an inoculum of 10(4) cfu per spot. MIC50 values of amoxycillin/clavulanate ranged from 8 to 16 mg/l. The antibacterial activity of amoxycillin/clavulanate did not show any statistically significant variation during the 12-year period.

Amoxicillin↗
PubMed1989

Effect of serotoninergic system on FSH secretion in male and female rats: evidence for stimulatory and inhibitory actions.

The present experiments were designed to assess the effect of the serotoninergic system on FSH secretion in prepubertal (16-, 18-, 20-, 26- and 30-day-old) and adult (60-day-old) male and female rats. The intraperitoneal administration of 5-hydroxytryptophan (5-HTP), a serotonin (5-HT) precursor, induced a significant increase of FSH levels in male rats at 16, 26, 30 and 60 days of age (p less than 0.01) but not at 18 and 20 days. In the females, no modifications in FSH concentrations in prepubertal and adult rats were observed after 5-HTP injection. These results indicate that there are sexual differences in the effect of the serotoninergic system on FSH secretion. Orchidectomy performed in prepubertal (30-day-old) and adult rats (60 days) besides increasing FSH levels, reversed the response of this hormone to 5-HTP administration, since in castrated rats the 5-HT precursor induced a significant decrease in serum FSH concentrations. The administration of 5-HTP to 30 day-old castrated rats treated with testosterone induced FSH release as it did in control animals of this age. In the adult castrated rats the administration of testosterone abolished the inhibitory effect of 5-HTP observed in castrated rats but did not invoke the stimulatory action of 5-HTP observed in the controls. This difference between prepubertal and adult rats appears to be related to a decrease in the sensitivity to testosterone of the central mechanism which controls FSH secretion. These results indicate that 5-HTP stimulates FSH release in normal rats and inhibits FSH release in castrated rats, testosterone concentration being a relevant factor in determining the 'type' of effect produced. The hypothalamic concentrations of 5-HT and 5-hydroxy-indoleacetic acid (5-HIAA) are significantly higher at the ages at which 5-HTP induces FSH release than at other ages suggesting that hypothalamic turnover of these substances is related is related to the releasing effect of 5-HTP on FSH.

5-Hydroxytryptophan↗
PubMed1989

[Pharmacokinetic interaction of ketoconazole, isoniazid and rifampicin].

Eight male tuberculous patients, between 20 and 60 years of age, were given Isoniazid 5 mg/kg and Ketoconazole 200 mg, first one at a time and then associated. Plasma concentrations were measured 0, 2 and 5 hs after taking the drugs. Isoniazid was measured by spectrophotometry and Ketoconazole by the microbiologic method with Candida albicans as test microorganism. When both drugs were given simultaneously Ketoconazole plasma concentration decreased 75% at 2 hs (p less than 0.025) and 85% at 5 hs (p less than 0.05), whereas that of Isoniazid remained unchanged (Table 1). Mean half-life of Isoniazid was 3.9 +/- 1.4 hs in 7 slow acetylators and 1.1 hs in one fast acetylator when given one at a time and 4.4 +/- 1.5 hs when given simultaneously. A similar study was conducted on 11 tuberculous patients who were given Rifampicin 10 mg/kg and Ketoconazole 200 mg, one at a time and concurrently. Rifampicin was measured by high pressure liquid chromatography. When Rifampicin and Ketoconazole were given concurrently plasma concentration of both drugs was reduced: Ketoconazole decreased 85% at 2 hs (p less than 0.025) and 98% at 5 hs (p less than 0.025) whereas Rifampicin decreased 45% at 2 hs (p less than 0.005) and 40% at 5 hs (p less than 0.005) (Table 2). Mean half-life of Rifampicin was 3.5 +/- 0.8 and 4.2 +/- 1.1 hs, respectively, when it was given alone and concurrently. Studies on chemical interactions between Isoniazid and Ketoconazole and between Rifampicin and Ketoconazole yielded negative results.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Uptake and metabolism of 3H-(+/-)-noradrenaline in the isolated perfused rat liver.

The influence of inhibitors of metabolism and uptake of noradrenaline on the 3H-noradrenaline removal from the perfusion fluid by the isolated rat liver was studied. Livers were perfused with 3 nmol/l 3H-noradrenaline and 3H-noradrenaline and 3H-metabolites were determined in effluent, liver and bile. After the perfusion with 14,900 +/- 920 dpm.g-1.min-1 during 90 min, cumulative removal of tritium was 323,574 +/- 63,103 dpm/g. 3H-metabolites recovered from the liver after 90 min perfusion represented 71.1 +/- 9.0% of total metabolite formation. Only the OMDA-fraction appeared in the perfusate; its approach to steady state of efflux was slow. The inhibition either of MAO or COMT changed neither the total removal of tritium nor the 3H-metabolites recovered from the liver. Cocaine (10 mumol/l) reduced the accumulation of 3H-noradrenaline in the liver. The uptake2 inhibitor corticosterone (30 mumol/l) diminished total removal of tritium and the 3H-metabolites recovered from the liver without changing the accumulation of 3H-noradrenaline. The hypothesis of two different compartments, one responsible for the metabolism and the other for the accumulation of the amine is discussed.

Animals↗
PubMed1988

[N-2-chloroethyl-N-ethyl-2-bromobenzylamine (DSP4) increases the liberation of 3H-noradrenaline produced by depolarization of the nerve ending].

When injected systemically to rodents, DSP4 inhibits the uptake of noradrenaline (NA) and depletes endogenous NA levels in the central nervous system and in the periphery. Pretreatment with the NA uptake blocker desipramine (DMI), with the NA precursor l-dopa or with the MAD inhibitor, pargyline, prevents the toxic effects of the compound. To investigate the mechanism of the NA depleting action of DSP4, the release of the neurotransmitter induced by nerve stimulation was studied "in vitro" in a tissue sensitive to the neurotoxic action of DSP4 such as the rat cerebral cortex previously loaded with tritiated NA. Incubation with 10 mumol/l DSP4 increased the spontaneous release of tritium from the cortex and produced a two-fold enhancement of tritium outflow during the stimulation of the cortical slices by exposure to K+ 20 mmol/l for 1 m. When the experiments were performed in a Ca++ free medium, DSP4 increased the spontaneous tritium outflow, but did not enhance the NA release by depolarization with K+. This latter effect could be due to the interaction with alpha-adrenoceptors since DSP4 did not potentiate the action of the alpha-antagonist yohimbine (1 mumol/l). DSP4, as did other uptake blockers, reduced the inhibitory effect of clonidine (0.1 mumol/l) on the NA release. Clonidine pretreatment "in vivo" (2 mg/kg), did not counteract the effect of DSP4 (25 mg/kg), suggesting that the enhanced release of NA induced by K+ does not play an important role in the depletion caused by DSP4. This is supported by the fact that DSP4 also enhanced the release of NA evoked by field stimulation of the rat vas deferens, a tissue resistant to the NA depleting action of the compound. The results indicate that the enhancement of the stimulation-induced release caused by DSP4, does not seem to play a triggering role in the NA depletion caused by the compound.

Animals↗
PubMed1988

[Fixed cutaneous sporotrichosis localized on the face, with an infrequently seen clinical picture].

A case of fixed cutaneous sporotrichosis in an urban patient in whom the contagious trauma could not be proved is commented on. Remarkable is the location of the lesions involving the face, which is extremely rare, as well as the morphology of the lesions, adopting the pattern of congestive erythema on which there were crusty-erythematous papules causing an intense itching which also preceded their onset.

Dermatomycoses↗
PubMed1988

Comparative activity of cefotetan against plasmid-encoded aminoglycoside-resistant enterobacteria strains.

304 strains of R-plasmid harbouring enterobacteria resistant to aminoglycosides were studied for their susceptibilities to a range of antibiotics, including cefotetan. Cefotetan and latamoxef were the most active of the four cephamycins tested and all were stable to the beta-lactamases produced by these strains. No new beta-lactamases (SHV-2, CTX-1, TEM-4, CAZ-1) were found in these strains capable of hydrolysing third generation cephalosporins. The activity of cefotetan against these multi-resistant, beta-lactamase producing strains may be of clinical value.

Aminoglycosides↗