Search PubMed⌕ Search

Biomedical subjects

M Morales

Publications and source records attributed to M Morales.

At least 145 records · Page 8Linked to original sources
PubMed1996

Horner's syndrome associated with a functional thyroid carcinoma in a dog.

A seven-year-old entire male Irish setter was presented because of a neck mass, prolapse of the third eyelid and apparent drooping of the upper eyelid. Historical findings included increased appetite as well as polyuria and polydipsia for about two weeks. The most remarkable findings on physical examination were right-sided Horner's syndrome, pre-scapular lymphadenopathy and a large, ventral cervical mass. Lateral cervical radiographs showed a large, soft tissue opacity surrounding the trachea and retropharyngeal area which was causing displacement and narrowing of the cervical trachea and oesophagus. Results of thyroid testing suggested hyperthyroidism. At necropsy, a large, invasive tumour was identified in the ventral cervical region and multiple metastases of various sizes were detected in the lungs. Histopathological examination of the tumour revealed follicular thyroid carcinoma and confirmed widespread pulmonary metastasis.

Animals↗
PubMed1996

Molecular subtyping of Neisseria meningitidis serogroup B: comparison of five methods.

In order to compare methods for subtyping Neisseria meningitidis serogroup B isolates, 96 isolates obtained from various locations in the United States and northwestern Europe were subtyped by five methods: monoclonal antibody (MAb)-based serotyping and serosubtyping, DNA macrorestriction analysis by pulsed-field gel electrophoresis (PFGE), multilocus enzyme electrophoresis (MEE), ribotyping, and PCR-restriction fragment length polymorphism of the internally transcribed spacer region of the rRNA operon (ITS PCR-RFLP). All N. meningitidis serogroup B isolates were typeable by PFGE, MEE, ribotyping, and ITS PCR-RFLP. Only 44.8% of the isolates were completely typeable (both serotype and serosubtype determination) by MAb-based serotyping and serosubtyping. 60.4% of the isolates could be serotyped but not serosubtyped, and 90.6% of the isolates could be either serotyped or serosubtyped. Simpson's discrimination indices of diversity for the methods were as follows: PFGE, 99.7%; MEE, 99.4%; ribotyping, 98.8%; MAb serotyping, 75.8%; MAb serotyping and/or serosubtyping 97.5%; and ITS PCR-RFLP, 84.2%. The high degree of diversity observed by PFGE, MEE, and ribotyping can be explained by the fact that isolates were collected from different geographic locations at various times. PFGE, MEE, and ribotyping showed greater discriminatory abilities than MAb-based serotyping and serosubtyping or ITS PCR-RFLP.

Antibodies, Monoclonal↗
PubMed1996

Cl channel blockers inhibit the volume-activated efflux of Cl and taurine in cultured neurons.

The effects of the Cl channel blockers 5-nitro-2-(3-phenylpropylamino)benzoic acid (NPPB), 1,9-dideoxyforskolin (DDF), dipyridamole, and niflumic acid and of the polyunsaturated fatty acids arachidonic, linolenic, and linoleic acids on regulatory volume decrease (RVD) and associated 125I and [3H]taurine fluxes in cultured rat cerebellar granule neurons were examined. Dose-response curves of NPPB, DDF, and dipyridamole showed 20-100% inhibition of RVD and osmolyte fluxes. Niflumic acid was less potent, requiring 150-600 microM to show effects of this magnitude. The polyunsaturated fatty acids (5-20 microM) inhibited 80-90% RVD and osmolyte fluxes, with arachidonic acid exhibiting the most potent effect. The volume-associated taurine efflux was somewhat higher in younger neurons, but the pharmacological sensitivity was essentially the same in immature and mature cells. The effects of all tested drugs on 125I and [3H]taurine fluxes were remarkably similar, indicating a close pharmacological sensitivity of the transport mechanism for the two osmolytes. This is in line with the suggestion of a common pathway for the volume-associated release of Cl and amino acids functioning as osmolytes.

Animals↗
PubMed1996

[Recurrent respiratory infections in patients with chronic obstructive bronchitis: medical treatment and costs].

The objective of this study is to describe usual medical management and costs associated with recurrent respiratory infections in subjects with chronic obstructive bronchitis in France. A prospective survey was performed in Autumn 1994 on a national sample of private practice pulmonologists (N = 71). Two hundred forty-four patients, presenting at least one infection of the lower respiratory tract, were included. Bronchitis was the most frequent acute exacerbation observed (94%). Pneumonia concerned 9% of the patients. Biological tests, X-rays and pulmonary function tests were prescribed for, respectively, 59, 65 and 45% of the patients. Following the visit, 15 patients were hospitalized (6%). The direct medical cost per acute exacerbation was estimated 3,289 francs (1994 value) of which 60% were hospital-related. An average 10.4 day sick-leave was prescribed to 21% of patients in employment. For those patients, this sick-leave was associated to an extra-cost of 1,264-1,876 francs for Social Security and of 0-2,553 francs out of pocket per episode varying according to their Benefit Regimen.

Acute Disease↗
PubMed1996

[Pyogenic osteomyelitis after a plantar puncture wound: analysis of a series of 8 cases].

BACKGROUND: The aim of this study was to know the incidence of osteoarticular infection secondary to plantar puncture, in the authors' center, and review the clinical characteristics, diagnosis and treatment. PATIENTS AND METHODS: A retrospective analysis of the cases of osteomyelitis and/or pyogenic arthritis secondary to plantar puncture admitted from 1986 to 1994 in the authors' hospital. RESULTS: Eight cases of osteoarticular infection secondary to plantar puncture (all males with a mean age of 37.2 years) were analyzed with a prevalence of 1.65% out of the total number of plantar punctures attended in the emergency department. The mechanism of the wound was, in all the cases, that of stepping on a nail. The most frequent clinical manifestations were pain and signs of local inflammation. Systemic repercussion was not observed in any case. A monomicrobial culture was obtained in 6 cases (in five P. aeruginosa was isolated). Combined surgical and antibiotic treatment was performed in 7 patients. A foreign body was found in only one case. The mean length of antibiotic treatment was five weeks. CONCLUSIONS: Initial surgical treatment of plantar punctures is fundamental, in addition to home instructions and follow up to avoid late severe infectious complications. The role of radiology and other diagnostic imaging techniques should be considered to detect foreign bodies. The role of prophylatic antibiotics is controversial but may be indicated in certain cases.

Adult↗
PubMed1996

[Hemophilia A: analysis of intron 18 and intron 7 of factor VIII gene and their role in a diagnostic strategy for carrier detection in a Chilean population].

Hemophilia A is an X-linked disorder of coagulation caused by a deficiency of factor VIII. A larger number of different mutations in the VIII gene have been identified. Thus, the detection of female carriers, depends upon the analysis of DNA polymorphisms in and near the factor VIII gene. Our aim was to develop a strategy, earlier reported, for carrier testing in families at risk of hemophilia A. In this study, we analyzed the DNA polymorphisms in 26 affected families, with use of the factor VIII intragenic polymorphisms identified by the restriction enzymes BclI and AlwNI, and by differential hybridization with sequence-specific oligonucleotide probes recognizing BclI and AlwNI polymorphism. While the DNA polymorphism detected by BcilI site in intron 18 of the factor VIII gene was informative for 38% families studied, the AlwNI/intron 7 polymorphism provided additional information (4%). The carrier status of the remaining 58% could be determined utilizing the other polymorphisms suggested by strategy. The two polymorphic sites used combined with the other polymorphisms, intragenic and extragenic, can generate levels of informativeness greater than 98%. We concluded that the strategy for carrier testing would be a good alternative in genetic counselling for hemophilia A, but its limitations must be carefully taken into account.

Chile↗
PubMed1995

A continuous spectrophotometric method for determining the monophenolase and diphenolase activities of apple polyphenol oxidase.

A continuous spectrophotometric method for the determination of the monophenolase and diphenolase activities of apple polyphenol oxidase is described. The method is based on the coupling reaction between 3-methyl-2-benzothiazolinone hydrazone (MBTH) and the quinone product of the oxidation of p-hydroxyphenyl propionic acid and 3,4-dihydroxyphenyl propionic acid in the presence of polyphenol oxidase. The lambda(max) and molar absorptivity (epsilon) for the MBTH-quinone adduct have been calculated. The presence of MBTH in the reaction medium decreases the lag period during the expression of monophenolase activity. The high value of V(mas) suggests the existence of a high catalytic constant. This, together with the value of epsilon for the MBTH-quinone adduct, makes this method more sensitive than other continuous methods.

Catechol Oxidase↗
PubMed1995

Open-label study to assess the efficacy, safety, and tolerability of fluvastatin versus bezafibrate for hypercholesterolemia.

Increased levels of total cholesterol and low density lipoprotein cholesterol (LDL-C) are associated with the development of coronary artery disease, which has become a worldwide public health problem. Clinical trials show that, in the long term, effective lowering of total cholesterol and raising of high density lipoprotein cholesterol (HDL-C) can slow atherosclerosis progression and reduce coronary artery disease risk. This study evaluated the efficacy, safety, and tolerability of fluvastatin versus bezafibrate (slow release) in patients with cholesterol > 241 mg/dL (6.2 mmol/liter) not responding to dietary treatment alone (cholesterol < 300 mg/day for 8 weeks). Patients were divided into 2 groups: group A (13 women, 7 men; mean age, 47.8 +/- 9.7 years; range, 30-70) received 40 mg fluvastatin once daily with their evening meal; group B (14 women, 6 men; mean age, 45 +/- 11 years, range, 25-68) received 400 mg bezafibrate once daily with either breakfast or their evening meal. After 12 weeks of treatment, the mean cholesterol decrease in group A was 27% (from 271 +/- 51.4 to 197.4 +/- 24.3 mg/dL; p < 0.001) versus 8% (from 278.6 +/- 33.2 to 255.8 +/- 20.3 mg/dL; p < 0.005) in group B. At the same time point, LDL-C was significantly decreased in group A (from 197.9 +/- 49 to 107.5 +/- 27.6 mg/dL; p < 0.001) but not in group B (from 181.6 +/- 39.6 to 173.3 +/- 24.3 mg/dL).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

The site of the inhibitory action of endogenous opioids in the superior cervical ganglion of the cat.

A low-frequency stimulus train to the preganglionic input inhibits synaptic transmission in the superior cervical ganglion (SCG) of the cat. The inhibition is blocked by naloxone as well as by selective antagonists at mu and delta opiate receptors, which suggests that the mediator is an endogenous opioid [27,29]. Exogenous opioid peptides, including methionine-enkephalin (Met-Enk), which is present in preganglionic axons of the SCG, inhibit ganglionic transmission by a naloxone-sensitive mechanism. In the present study we test, in the anesthetized cat, whether the naloxone-sensitive synaptic inhibition is mediated by a pre- and/or post-synaptic mechanism. As a test of presynaptic inhibition, we measured the acetylcholine (ACh) released by preganglionic stimulation into the venous effluent of the perfused SCG. As a test of post-synaptic inhibition, we measured the effect of a preganglionic conditioning train on the ganglion cell firing evoked by ganglion-stimulant drugs injected into the arterial supply of the ganglion. In presence of naloxone (3 microM), which blocked the synaptic inhibition, the amount of ACh released by stimulated preganglionic axons did not change. Thus, the endogenous opioid which mediates the naloxone-sensitive inhibition does not act by depressing ACh release. In contrast, the ganglion cell firing evoked by ganglion-stimulant drugs was markedly depressed by a conditioning train, and naloxone blocked the depression, which suggests that the endogenous mediator of the naloxone-sensitive inhibition acts postsynaptically to decrease the excitability of ganglion cells. Exogenous Met-Enk depressed both ACh release by preganglionic stimulation and the firing of ganglion cells evoked by ganglion-stimulant drugs.(ABSTRACT TRUNCATED AT 250 WORDS)

Anesthesia↗
PubMed1995

Differentiation of hippocampal progenitor cells in vitro: temporal expression of intercellular coupling and voltage- and ligand-gated responses.

Mechanisms regulating the expression of intercellular coupling, development of membrane excitability, and cellular responsiveness to neurotransmitters during neuronal ontogeny are largely unknown. To define the temporal relationship among these properties during neurogenesis, murine embryonic hippocampal progenitor cells immortalized with a temperature-sensitive allele of the SV40 large T-antigen were examined during successive stages of neuronal differentiation in vitro using patch clamp, dye coupling, and Ca2+ imaging techniques. Electrotonic and dye coupling between untreated neuroblasts were frequent in cells maintained at the temperature (39 degrees C) nonpermissive for T-antigen expression. However, as neuroblasts differentiated into neurons under the influence of interleukin-7 added alone or concurrently with transforming growth factor-alpha after basic fibroblast growth factor, both junctional conductance and the extent of dye coupling progressively decreased. Voltage-dependent inward currents were present within 2 to 6 days after differentiating treatments began. During intermediate developmental stages (3 to 5 days in culture), cells became responsive to GABA (> or = 100 microM) but not to glutamate, glycine, or to acetylcholine (< or = 1 mM), as indicated by [Ca2+]i measurements and patch clamp recordings. In contrast, voltage- and ligand-gated responses but not electronic coupling were frequently observed in mature neuronal primary cultures. Together, these results indicate that certain cytokines may orchestrate the progressive expression of functional neuronal phenotypes in vitro, in which the gradual disappearance of intercellular coupling parallels the onset of voltage-dependent responses and both of which precede the expression of neurotransmitter chemosensitivity.

Animals↗
PubMed1995

Naloxone blocks the antianxiety but not the motor effects of benzodiazepines and pentobarbital: experimental studies and literature review.

The role of opioid systems in the anticonflict effect of chlordiazepoxide, diazepam and pentobarbital was evaluated with a modified Vogel procedure. First, morphine, ineffective by itself, was combined with subeffective or marginally effective doses of the benzodiazepines in order to detect possible potentiation. However, the combined treatment reduced licking in the Vogel procedure as well as in a licking test where no shock was administered. Several doses of the benzodiazepines and pentobarbital were then administered in combination with several doses of the opiate antagonist naloxone. A dose-dependent inhibition of anticonflict effect was obtained. In an additional experiment, it was shown that naloxone blocked the effects of diazepam in the elevated plus-maze procedure. Motor deficiencies, as evaluated with a rotarod test, produced by the benzodiazepines and pentobarbital could not be antagonized by naloxone. It is concluded that opioids are important for the anticonflict but not for the motor effects of these drugs. An analysis of published studies concerning the interaction of opioids and benzodiazepines in several procedures supposed to reflect anxiolytic effects shows that the inhibition obtained with naloxone is reliable and not procedure specific. The mechanisms by which opiate antagonists produce this inhibition of anticonflict activity are not known. It is tentatively suggested that opioid activation associated with stress may be a necessary component of anxiolysis.

Animals↗
PubMed1995

Left ventricular outflow tract obstruction in TGA: treatment with LV-to-PA valved conduit.

Progressive or recurrent left ventricular outflow tract obstruction after a previous Mustard or Senning operation represents a rare but challenging problem. The obstruction can be resected in some patients, but abnormal attachment of the mitral valve or a long fibromuscular tunnel represents a difficult surgical problem. Between 1979 and 1993, we encountered this type of left ventricular outflow tract obstruction in 10 patients, 4 to 13 years after the atrial repair. They ranged in age from 5 to 15 years (mean, 8.8 years) and weighed between 11.5 and 47 kg (mean, 25.3 kg). Operations were performed through a left thoracotomy with the patient on hypothermic cardiopulmonary bypass but without aortic cross-clamping. The left atrial appendage and descending aorta were cannulated. Good relief of the gradient was obtained in all patients (mean residual gradient, 14.8 mm Hg). All patients survived the operation. One patient died suddenly at home 6 months later; 2 patients required conduit replacement. All 9 long-term survivors are asymptomatic as of 6 months to 8 years after their conduit placement or replacement. We recommend the placement of a left ventricle-to-pulmonary artery valved conduit for the relief of severe left ventricular outflow tract obstruction arising after a Senning or Mustard operation that cannot be managed by other means.

Adolescent↗
PubMed1995

Selective antagonism of AMPA receptors unmasks kainate receptor-mediated responses in hippocampal neurons.

Although both protein and mRNAs for kainate receptor subunits are abundant in several brain regions, the responsiveness of AMPA receptors to kainate has made it difficult to demonstrate the presence of functional kainate-type receptors in native cells. Recently, however, we have shown that many hippocampal neurons in culture express glutamate receptors of the kainate type. The large nondesensitizing response that kainate induces at AMPA receptors precludes detection and analysis of smaller, rapidly desensitizing currents induced by kainate at kainate receptors. Consequently, the functional significance of these strongly desensitizing glutamate receptors remains enigmatic. We report here that the family of new noncompetitive antagonists of AMPA receptors (GYKI 52466 and 53655) minimally affects kainate-induced responses at kainate receptors while completely blocking AMPA receptor-mediated currents, making it possible to separate the responses mediated by each receptor. These compounds will allow determination of the role played by kainate receptors in synaptic transmission and plasticity in the mammalian brain, as well as evaluation of their involvement in neurotoxicity.

Animals↗
PubMed1995

Spatial interaction between neighbouring counties: cancer mortality data in Valencia Spain.

The statistical analysis of geographical mortality data has usually been approached via regression models that include appropriate covariates. These models assume stochastic independence of mortality counts for neighbouring sites, a questionable assumption that spatial automodels (Besag, 1974, Journal of the Royal Statistical Society, Series B 36, 192-236) make unnecessary. This paper presents the use of the autopoisson distribution in order to detect spatial interaction between neighbouring sites. If this interaction results in being nonsignificant, the auto-Poisson distribution reduces to a usual Poisson regression model, a particular case of generalized linear models (McCullagh and Nelder, 1989, Generalized Linear Models, 2nd edition. London: Chapman and Hall) which can be analyzed with the GLIM package.

Colonic Neoplasms↗
PubMed1994

Effect of lysine methylation and other ATPase modulators on the active site of myosin subfragment 1.

Many and diverse modifications of the myosin subfragment 1 (S-1) increase (modulate) its ATPase activity, including interaction of this particle with actin; a recent addition to these modifications is the extensive lysine modification of S-1 that seems prerequisite to crystallizing it for structure analysis. In this study we first established kinetically the ATPase modulations induced by various treatments of the myosin S-1 enzyme, and we also measured two properties of the S-1 active site--the affinity with which the site binds (a fluorescent analog of) the enzymatic nucleotide product and the access that a fluorescence quencher has to the bound ADP product--in an effort to get at the mechanism of modulation. Modulations achieved by substituting Ca2+ for the normal Mg2+ cocatalyst or by substituting Cl- for the normal carboxylate anion seem due to the product being held more loosely by the modulated enzyme. In other illustrative modulations (lysine methylation, or alkylation of Cys-707, or transition from neutral pH to pH 9.2) nucleotide product affinity and access to quencher do change, but not in a pattern explained simply by a lifting of product inhibition. Lysine methylation results in weaker binding of nucleotide product.

Adenosine Diphosphate↗
PubMed1994

Glucagon-like peptide 1: a potent glycogenic hormone.

GLP-1(7-36)amide is an insulinotropic peptide derived from the intestinal post-translational proglucagon process, the release of which is increased mainly after a carbohydrate meal; also, its anti-diabetogenic effect in normal and diabetic states has been reported. In this study, GLP-1(7-36)amide stimulates the formation of glycogen from glucose in isolated rat hepatocytes, such a glycogenic effect being achieved with physiological concentrations of the peptide. The GLP-1(7-36)amide-induced glycogenesis is abolished by glucagon, and it is accompanied by stimulation of the glycogen synthase alpha activity and by a decrease in the basal and glucagon-stimulated cyclic AMP content. These findings could explain, at least in part, the GLP-1(7-36)amide insulin-independent plasma glucose lowering effect.

Animals↗
PubMed1994

Rectification properties and Ca2+ permeability of glutamate receptor channels in hippocampal cells.

Excitatory amino acids exert a depolarizing action on central nervous system cells through an increase in cationic conductances. Non-NMDA receptors have been considered to be selectively permeable to Na+ and K+, while Ca2+ influx has been thought to occur through the NMDA receptor subtype. Recently, however, the expression of cloned non-NMDA receptor subunits has shown that alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors are permeable to Ca2+ whenever the receptor lacks a particular subunit (edited GluR-B). The behaviour of recombinant glutamate receptor channels predicts that Ca2+ would only permeate through receptors that show strong inward rectification and vice versa, i.e. AMPA receptors with linear current-voltage relationships would be impermeable to Ca2+. Using the whole-cell configuration of the patch-clamp technique, we have studied the Ca2+ permeability and the rectifying properties of AMPA receptors, when activated by kainate, in hippocampal neurons kept in culture or acutely dissociated from differentiated hippocampus. Cells were classified according to whether they showed outward rectifying (type I), inward rectifying (type II) or almost linear (type III) current-voltage relationships for kainate-activated responses. AMPA receptors of type I cells (52.2%) were mostly Ca(2+)-impermeable (PCa/PCs = 0.1), while type II cells (6.5%) expressed Ca(2+)-permeable receptors (PCa/PCs = 0.9). Type III cells (41.3%) showed responses with low but not negligible Ca2+ permeability (PCa/PCs = 0.18). The degree of Ca2+ permeability and inward rectification were well correlated in cultured cells, i.e. more inward rectification corresponded to higher Ca2+ permeability.(ABSTRACT TRUNCATED AT 250 WORDS)

Action Potentials↗