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Biomedical subjects

M Torres

Publications and source records attributed to M Torres.

At least 235 records · Page 13Linked to original sources
PubMed1992

Diagnosis of brain death: superiority of perfusion studies with 99Tcm-HMPAO over conventional radionuclide cerebral angiography.

The use of technetium-99m hexamethyl-propyleneamine oxime (99Tcm-HMPAO) in the diagnosis of brain death has been evaluated in 41 studies of 37 patients with severe brain injury, who were under the effect of drugs or when other diagnostic methods were equivocal. HMPAO studies were compared with conventional radionuclide angiography performed simultaneously by intravenous administration of HMPAO as a bolus. The ages of patients ranged from 4 months to 75 years. Dynamic flow images and 5-min static uptake images were acquired following bolus injection of 555 Mbq of 99Tcm-HMPAO. All patients showing no brain uptake were confirmed as brain-dead by standard clinical criteria, with no contradictory cases in the static study. In addition, all patients who were not brain-dead showed HMPAO uptake at least in the brainstem. Dynamic flow images were equivocal in five patients, four of whom had no uptake on static images and clinically confirmed brain death. In addition, two other cases showed "mismatched" dynamic and static images: in one case no perfusion was observed on flow images but uptake restricted to the posterior fossa was seen on static images; the other case showed perfusion on the dynamic study and static imaging revealed hemispheric uptake with no posterior fossa uptake. Static perfusion 99Tcm-HMPAO studies offer advantages over conventional brain scintigraphy, better results being due to adequate assessment of posterior fossa activity and avoiding equivocal studies.

Adolescent↗
PubMed1992

Myocardial damage following coronary bypass surgery: assessment with antimyosin antibody uptake.

To assess the role of 111In antimyosin antibody (AbAm) in the delineation of myocardial damage following coronary bypass surgery, we studied 51 consecutive patients who underwent coronary surgery, 27 of whom had a history of prior myocardial infarction. All patients underwent a diagnostic protocol comprising: (1) 99Tcm pyrophosphate (PYP) and AbAm injection 48 h after surgery (AbAm imaging 24 and 48 h post-injection) (myocardial/background and myocardial/lung ratios were obtained respectively from the computer image); (2) Radioimmunoassay (RIA) serum CK-B levels from samples obtained immediately before surgery, and 24 and 48 h later; (3) clinical and ECG follow-up. Twenty-five patients showed positive AbAm studies, 10 had positive PYP images, and 21 had CK-B levels above normal limits at 24 h. One patient with abnormal AbAm, PYP and CK-B studies had new Q waves on the ECG after surgery. This patient was considered to have sustained a peri-operative myocardial infarction. The large number of positive AbAm studies probably reflects myocardial damage frequently associated with coronary bypass surgery.

Antibodies↗
PubMed1992

[Non-Hodgkin's lymphomas. I. Clinico-biological features of 307 cases].

PURPOSE: To assess the clinico-biological features appearing in 307 patients with non-Hodgkin's lymphomas (NHL). PATIENTS AND METHODS: The clinical records of 338 patients diagnosed of NHL between January 1975 and December 1988 were revised in retrospect. All cases with histologic diagnosis of NHL aged over 14 years were included, and classified in accordance with the Working Formulation criteria. The following data were analysed: age, sex, first complaints, time elapsed since onset, histologic type, number of sites involved, bulky disease, anaemia, thrombocytopenia, LDH, stage, type of treatment and initial response, survival, and cause of death. The statistical evaluation was performed by actuarial analysis (Kaplan and Meier) and comparison (log-rank test) of survival. RESULTS: According to the three categories of the malignancies, the NHL were distributed into low-grade (37.8%), intermediate (36.1%) and high-grade (26.9%). The mean age of the series was 56.6 years and the M/F ratio was 1.3. Lymph node enlargement was the commonest finding; 36.4% of the patients had symptoms related with the disease, and 26.7% had bulky disease. Anaemia was present in 37.7% of the cases and thrombocytopenia in 14.3%, with similar distribution among the three grades. High LDH levels were found in 44% of the patients. At diagnosis, 85% of the patients were in advanced stages (III+IV) already. Complete response was attained in 51.1% of the cases, with median survival of 48 months. CONCLUSIONS: The clinico-evolutive data found here are similar to other reports in the literature. In one-half of the patients the cause of the first visit is lymph node enlargement. Complete remission is achieved by one out of two patients, this figure being similar for each of the histologic groups. The Working Formulation is useful in determining the different prognostic groups with respect to survival.

Adolescent↗
PubMed1992

[Tuberculosis in 7 general hospitals in Andalusia. Grupo Andaluz para el Estudio de las Enfermedades Infecciosas].

BACKGROUND: To know the clinical features of tuberculosis in our environment, to evaluate its diagnostic techniques and therapeutic options as well as the evolution of patients. PATIENTS AND METHODS: Multicenter retrospective study of 1115 patients with tuberculosis, diagnosed between 1984 and 1988 in the population based areas of 7 Hospitals from Andalusia (Spain). RESULTS: The mean age was less than 40 ages, the exponential growing of the number of cases a year in which the influence of drug addicts could be an important factor, an elevated proportion (45%) of extrapulmonary tuberculosis and disseminated forms, and a social environment of 20% of cases being alcoholics or drug addicts. A good use of diagnostic techniques is recorded, although the use of culture as diagnostic tools is lacking. The usual treatment was three drugs for nine months. The global evolution seems good. However a global mortality of 6.4% is recorded, mainly in disseminated forms and among patients with risk factors for developing tuberculosis. SUMMARY: We have seen an increment among tuberculosis cases, as well as a change in the clinical spectrum of the disease, linked to social illness and drug addiction. The diagnostic approach to tuberculosis seems to be appropriate. The follow up of patients is somewhat confusing.

Adolescent↗
PubMed1991

An inherited defect of neutrophil motility and microfilamentous cytoskeleton associated with abnormalities in 47-Kd and 89-Kd proteins.

A 2-month-old male Tongan infant presented with fever, severe skin and mucosal infections, hepatosplenomegaly, thrombocytopenia, and normal neutrophil counts. While polymorphonuclear neutrophil (PMN) morphology was normal, several neutrophil motile functions were found to be altered in the patient. Furthermore, two siblings had died in infancy with a similar clinical picture, raising the possibility of an inherited neutrophil defect. Random migration and chemotaxis, assessed by the under agarose method, were profoundly impaired. Actin polymerization, as measured by flow cytometry of N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)phallacidin (NBD-phallacidin)-stained PMNs, showed lower basal F-actin and a 1.75-fold increase in response to 10(-7) mol/L formyl-methionyl-leucyl-phenylalanine (FMLP) compared with a 4.51-fold increase in control. Microscopic examination of NBD-phallacidin-stained PMN spread on glass showed decreased area of spreading and F-actin-rich filamentous projections distinct from control. The early phase of FMLP-induced right angle light scattering was absent, similar to the effect caused by cytochalasin-B (CB), an inhibitor of actin polymerization. Accordingly, FMLP induced secretion of elastase without the addition of CB. Staphylococcus aureus killing was 50% of control whereas superoxide production response to FMLP and surface expression of CD11b were greater than twice normal. Partial defects in actin polymerization and scatter were seen in the parents and release of elastase, in the absence of CB, was also increased in both parents. Sodium dodecyl sulfate-polyacrylamide electrophoresis of whole cell proteins from the patient showed a marked decrease in an 89-Kd protein (8% of control) and a marked increase in a 47-Kd protein (4.2-fold). Both mother and father had decreased 89-Kd (77% and 42% of control) and increased 47-Kd proteins (2- and 3.4-fold), although neither had recurrent infections or chemotactic defects. These studies describe a new inherited actin dysfunction syndrome associated with severe propensity to fungal infection and draw attention to the proteins of apparent molecular weights of 89 Kd and 47 Kd, which may be of great importance in the regulation of actin polymerization in human PMNs.

Actin Cytoskeleton↗
PubMed1991

Di(1,N6-ethenoadenosine)5', 5'''-P1,P4-tetraphosphate, a fluorescent enzymatically active derivative of Ap4A.

Di(1,N6-ethenoadenosine)5',5'''-P1,P4-tetraphosphate, epsilon-(Ap4A), a fluorescent analog of Ap4A has been synthesized by reaction of 2-chloroacetaldehyde with Ap4A. At neutral pH this Ap4A analog presents characteristics maxima at 265 and 274 nm, shoulders at ca 260 and 310 nm and moderate fluorescence (lambda exc 307 nm, lambda em 410 nm). Enzymatic hydrolysis of the phosphate backbone produced a slight hyperchromic effect but a notorious increase of the fluorescence emission. Cytosolic extracts from adrenochromaffin tissue as well as cultured chromaffin cells were able to split epsilon(Ap4A) and catabolize the resulting epsilon-nucleotide moieties up to epsilon-Ado.

Adrenal Medulla↗
PubMed1991

Paradoxical potentiation by low extracellular Ca2+ of acute chemical anoxic neuronal injury in cerebellar granule cell culture.

Acute chemical anoxic injury was produced in primary cerebellar granule cell cultures incubated with iodoacetate (IAA) alone or IAA combined with potassium cyanide (KCN). Cytotoxicity was assessed using Trypan blue exclusion or LDH release. Four millimolars of KCN induced approx 30% neuron death at 3 h, whereas greater than 50% cell death was produced by 0.2 mM IAA. No potentiation of cytotoxicity was observed by IAA + KCN. A total of 0.2 mM IAA produced an early major reduction of intracellular ATP prior to the onset of neuron injury or reduction in intracellular glutathione (GSH). Medium Na+ replacement by choline, K+, or methylglucamine protected against IAA-induced neuronal injury, reduced the rate of decline of intracellular ATP but had no effect on intracellular GSH. Some 80% neuronal survival was obtained when Na+ was deleted from the medium even after the intracellular ATP had been reduced to less than 10% of control. Removal of Ca2+ from the medium had no effect on control culture, Trypan blue exclusion, GSH, or ATP, but potentiated the onset and magnitude of IAA-induced cytotoxicity. ATP and GSH decline. Loading of granule cells with the Ca2+ chelator Fura-2 did not influence IAA-induced cytotoxicity in control or low Ca2+ media. Addition of 50 microM glutamate had a minimal cytotoxic effect over 3 h and the combined addition of 0.2 mM IAA plus 50 microM glutamate did not potentiate IAA-induced injury. The glutamate receptor antagonists, D-2-amino-5-phosphonovaleric acid (APV) or kynurenate did not block IAA-induced injury in control medium but inhibited the potentiation of toxicity seen in the low Ca2+ medium. This study suggests the use of IAA as a chemical anoxic agent in cerebellar granule cell culture. The early, dose-dependent decline in ATP may be dissociated from GSH change. Acute IAA-induced injury is Na+/Cl- dependent but paradoxically potentiated in low Ca2+ medium. The low Ca2+ potentiated component was sensitive to glutamate/NMDA receptor antagonists and associated with reduction of intracellular GSH.

2-Amino-5-phosphonovalerate↗
PubMed1991

Carbachol induced release of diadenosine polyphosphates--Ap4A and Ap5A--from perfused bovine adrenal medulla and isolated chromaffin cells.

The diadenosine polyphosphates--Ap4A and Ap5A--were released from perfused bovine adrenal glands and recently isolated chromaffin cells by the action of carbachol. The H.P.L.C. technique reported here allowed the quantification of pmol amounts of these compounds present in biological samples from the perfusion media after stimulation. Both compounds (Ap4A and Ap5A) were identified by the retention time in H.P.L.C. chromatography, co-elution with standards, re-chromatography and destruction by the phosphodiesterase action. Bovine adrenal glands stimulated with 100 microM carbachol released 0.47 +/- 0.12 nmol/gland of Ap4A and 1.11 +/- 0.26 nmol/gland of Ap5A. Isolated bovine chromaffin cells after 100 microM carbachol, as secretagogue, released 11.1 +/- 0.8 pmol/10(6) cells of Ap4A and 15.8 +/- 1.1 pmol/10(6) cells of Ap5A. The ratio of these compounds with respect to the exocytotically released ATP and catecholamines was in the same order as that found in isolated chromaffin granules.

Adenosine Triphosphate↗
PubMed1991

Further evidence for a dopaminergic involvement in the renal action of centrally administered atrial natriuretic peptide in rats.

Intracerebroventricular (ICV) administration of atrial natriuretic peptide (ANP) induces an increase of urinary volume and sodium excretion in conscious male hydrated rats. The involvement of brain dopaminergic neurones in the ICV-ANP renal action was investigated. Diuretic and natriuretic action of ANP was prevented by inhibition of tyrosine hydroxylase activity with alpha-methyl-p-tyrosine treatment and was absent following selective central dopaminergic denervation with ICV administration of 6-hydroxydopamine in combination with desmethylimipramine (IP). Our results suggest that ANP acts centrally, at least in part, via an interaction with endogenous dopamine neurones.

Analysis of Variance↗
PubMed1991

Prevalence of HIV antibody in a noninner-city university hospital emergency department.

STUDY HYPOTHESIS: To determine the prevalence of antibody to human immunodeficiency virus (HIV) in trauma and nontrauma patients not identified as having known HIV infection in a noninner-city university teaching hospital emergency department, and to determine the frequency with which treating emergency physicians are knowledgeable of patients' risk factors for HIV infection. POPULATION: ED patients between 18 and 59 years old with injuries that met trauma center triage criteria or with nontrauma-related illness who had blood drawn for physician-requested laboratory tests and for whom an extra aliquot of blood was available for HIV antibody testing. METHODS: All serum samples were first tested for antibody to HIV by enzyme-linked immunosorbent assay. If positive, the specimen was retested. All repeatedly reactive specimens were analyzed by Western blot test. The treating physician completed a questionnaire regarding the patient's illness and risk factors for HIV infection after the patient's care was completed. RESULTS: Two of 100 major trauma patients (confidence interval, 0% to 5%) and seven of 100 nontrauma patients (confidence interval, 2% to 12%) had antibody to HIV. The seropositive rate by age and clinical group varied from 0% to 12.5%, with the highest rates in the 30- to 39-year-old group of nontrauma patients. The difference in proportions of seropositivity between the sexes was not statistically significant. Physicians obtained information regarding homosexual or bisexual behavior, IV drug use, and hemophilia from 52% of the nontrauma patients and only 17% of trauma patients. None of 30 trauma patients for whom data were available and only two of the 100 nontrauma patients gave a history of any high-risk behavior. CONCLUSION: Although the sampling technique we used has limitations, the prevalence of HIV infection in our noninner-city ED is similar to that recently reported from inner-city EDs. This is in contrast to previous reports of low rates of HIV infection among ED patients in nonurban settings. Physician assessment of risk factors was incomplete in the majority of our patients. Patients rarely acknowledged any high-risk behavior. It is essential that emergency health care workers take maximum diligence to prevent exposure to blood and other body fluids from all ED patients.

Adult↗
PubMed1991

Genetic and molecular analysis of new female-specific lethal mutations at the gene Sxl of Drosophila melanogaster.

We have isolated three female-specific lethal mutations at the gene Sex-lethal (Sxl): Sxlfb, Sxlfc and Sxlfd. We have carried out the complementation analysis between these mutations and other previously reported Sxlf mutations. It is possible to classify the alleles tested in this report into two complementation groups: the bc group defined by Sxlfb, and Sxlfc, and the LS group defined by SxlfLS. The other alleles tested affect both complementation groups albeit with different degrees. Contrary to what happens with mutations at the LS group, mutations at the bc group do not affect sex determination, nor late dosage compensation nor oogenesis. Both Sxlfb and Sxlfc present a DNA insertion of at least 5 kb between position -10 and -11 on the molecular map, within the fourth intron. On the contrary, Sxlfd, a strong mutation affecting all Sxl functions, is not associated to any detectable DNA alteration in Southern blots, so that it seems to be a "point" mutation. In agreement with their phenotypes, both Sxlfc/SxlfLS and Sxlfc homozygous female larvae express only the late Sxl transcripts characteristic of females, while females homozygous for SxlfLS express only the late Sxl transcripts characteristic of males. Moreover, Sxlfc presents a lethal synergistic interaction with mutations at either da or the X:A ratio, two signals that define the initial activity state of Sxl, while SxlfLS do not. These data suggest that the two complementation groups are related to the two sets of early and late Sxl transcripts, which are responsible for the early and late Sxl functions, respectively: Sxlfb and Sxlfc would affect the early functions and SxlfLS would affect the late Sxl functions.

Alleles↗
PubMed1991

Immunoscintigraphy of lung cancer using 111In-labelled antiCEA F023C5-F(ab')2 fragments.

Forty-one patients with known lung carcinoma or suspicion of bearing this disease were studied with 111In-antiCEA F023C5-F(ab')2. Five patients with positive results were further studied to assess in vivo specificity using 111In-4C4-F(ab')2 (MoAb antihepatitis). Immunoscintigraphic results have been compared to immunohistochemistry in 16 patients. Tumour visualization with non-specific MoAb was present in all five patients although the maximum tumour/background (T/B) ratio obtained was 1.51. Therefore a 'specificity criterion' has been applied to examinations performed with MoAb antiCEA. There was considered to be a positive result when the T/B ratio was greater than 1.60. Results obtained in this way for thoracic lesions were 25/34 true positive (TP) (73%) and 6/7 true negative (TN) (86%). When studies were analysed visually only, the results were 32/34 TP (94%) and 3/7 TN (43%). In addition, immunoscintigraphic results are more concordant with immunohistochemical results when the specificity criterion is applied. In metastatic lesions results were 9/13 TP (69%) with only 1/3 TP (33%) for liver metastasis (anatomic site of lowest detection ability). SPECT imaging did not improve results over planar images, although it clearly contributed to a better anatomic location of lesions. The constant presence of non-specific uptake in thoracic lesions makes it necessary to establish a T/B ratio limit in order to obtain adequate specificity with the immunoscintigraphic technique.

Adenocarcinoma↗
PubMed1991

Ca(2+)-independent release of glutamate during in vitro anoxia in isolated nerve terminals.

The effects of in vitro anoxia on the release of glutamate in isolated nerve terminals were studied. The extra-synaptosomal concentration of glutamate ([Glu]ext) under aerobic conditions was 2.3 microM and increased to 4.9 microM after 10 min of anoxia. However, when synaptosomes were incubated in the presence of lactate plus pyruvate instead of glucose, to prevent anaerobic glycolysis, anoxia induced an eightfold increase in the [Glu]ext. The accumulation of glutamate in the external medium during anoxia was Ca2+ independent and insensitive to a significant reduction of the Ca(2+)-dependent release of the amino acid. These results indicate that a Ca(2+)-independent efflux of cytoplasmic glutamate occurs during in vitro anoxia in isolated nerve terminals.

4-Aminopyridine↗
PubMed1991

Characterization of diadenosine tetraphosphate (Ap4A) binding sites in cultured chromaffin cells: evidence for a P2y site.

1. Diadenosine tetraphosphate (Ap4A) a dinucleotide, which is stored in secretory granules, presents two types of high affinity binding sites in chromaffin cells. A Kd value of 8 +/- 0.65 x 10(-11) M and Bmax value of 5420 +/- 450 sites per cell were obtained for the high affinity binding site. A Kd value of 5.6 +/- 0.53 x 10(-9) M and a Bmax value close to 70,000 sites per cell were obtained for the second binding site with high affinity. 2. The diadenosine polyphosphates, Ap3A, Ap4A, Ap5A and Ap6A, displaced [3H]-Ap4A from the two binding sites, the Ki values being 1.0 nM, 0.013 nM, 0.013 nM and 0.013 nM for the very high affinity binding site and 0.5 microM, 0.13 microM, 0.062 microM and 0.75 microM for the second binding site. 3. The ATP analogues displaced [3H]-Ap4A with the potency order of the P2y receptors, adenosine 5'-O-(2 thiodiphosphate) (ADP-beta-S) greater than 5'-adenylyl imidodiphosphate (AMP-PNP) greater than alpha, beta-methylene ATP (alpha, beta-MeATP), in both binding sites. The Ki values were respectively 0.075 nM, 0.2 nM and 0.75 nM for the very high affinity binding site and 0.125 microM, 0.5 microM and 0.9 microM for the second binding site.

Animals↗