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Biomedical subjects

M Gallego

Publications and source records attributed to M Gallego.

At least 91 records · Page 5Linked to original sources
PubMed1997

Subcellular analysis of Tyr-aminopeptidase activities in the developing rat cerebellum.

The endogenous opioid system seems to play important roles in the developing cerebellum. The first opioid peptide isolated, Met-enkephalin, is expressed transiently in this brain area. In the present study, several enzyme activities capable of hydrolyzing enkephalins are measured during the first month of cerebellar development, using Tyr-beta-naphthylamyde as substrate and puromycin as inhibitor of one of the membrane-bound aminopeptidases. Puromycin-sensitive soluble and membrane-bound aminopeptidase activities decrease in the synaptosomal and mitochondrial fractions at the end of the first month of life, just when enkephalin-like immunoreactivity decreases in the cerebellum. Membrane-bound enzyme also decreases in the myelinic fraction. Synaptosomal activity increases after birth, coinciding with decreases in the activity in the microsomal fraction. Puromycin-insensitive and membrane-bound aminopeptidase shows less significant developmental changes and they occur mainly in the first week of life, coinciding with the axonal and dendrite growth. These results could suggest a possible role of these enzymes, together with the rest of the opioid system, in cerebellar development.

Aminopeptidases↗
PubMed1997

Identification of avian dendritic cells in the spleen using a monoclonal antibody specific for chicken follicular dendritic cells.

BACKGROUND: In the chicken, circulating antigens enter the splenic white pulp via the Schweigger-Seidel sheaths (ellipsoids), where they are bound by cells, the ellipsoid associated cells (EAC), which are located on the periphery of the ellipsoid. There is an increasing body of evidence that these antigen-binding cells move through the PALS, to be finally located within the germinal centers, where these antigen-transporting EAC function as follicular dendritic cells (FDC). The aim of the current study was to further study the relationship between the EAC, the FDC, and the antigen-bearing EAC which migrate through the splenic white pulp. METHODS: In order to identify the splenic FDC and their presumed migrating EAC precursors in the chicken, we used a monoclonal antibody produced against chicken FDC and an antiserum anti-S-100 protein which identifies chicken dendritic cells in lymphoid organs. RESULTS: Cells reacting with the 74.3 monoclonal antibody, which identifies FDC, were found within the germinal center, around the penicilliform capillary, in the periellipsoidal white pulp, and in the periarteriolar lymphatic sheaths (PALS). S-100+ cells were found in these same locations. CONCLUSIONS: A comparison between the staining patterns obtained with both antibodies strongly suggested that the intrasplenic distribution of 74.3+ cells was identical with that of FDC, EAC, and antigen-binding EAC migrating in the PALS. Therefore, the 74.3 monoclonal antibody identified not only FDC but also the splenic precursor cells of FDC, in accordance with the hypothesis of the migration of the EAC through the white pulp. S-100+ cells were more numerous than 74.3+ cells, which is in accordance with the fact that S-100 protein antibody stains both FDC and interdigitating dendritic cells (ID). This has allowed us to suggest that 74.3- EAC may represent precursors of ID. The current findings reinforce previous investigations, which provided evidence supporting the migration of EAC through the PALS and further supported the hypothesis which considers EAC precursors of FDC.

Animals↗
PubMed1997

Rapid solid-phase extraction/derivatization system for sample preparation and gas chromatographic/mass spectrometric determination of drugs in human urine.

A novel automatic system has been developed for the rapid solid-extraction and derivatization of different drugs and their metabolites from urine, prior to further analysis. Manual injection of underivatized/derivatized drugs in a GC/MS system, in which the quadrupole mass filter was operated conventionally, provided high sensitivity and selectivity at the selected m/z value. The precision (2.1-6.8%) is acceptable and the overall recovery from urine was determined to be ca. 95%. The effectiveness of this approach is demonstrated with data obtained from different urine samples which had tested positively.

Calibration↗
PubMed1997

Interaction mechanisms of imipramine and desipramine with enkephalin-degrading aminopeptidases in vitro.

In the last few years, considerable evidence has appeared concerning the importance of the opioid systems in the action mechanism of some antidepressant drugs. This action mechanism could be mediated through the inhibition of the enzymes responsible for enkephalin degradation. In this sense, imipramine treatment in vivo increases the enkephalin levels, and this effect is enhanced by inhibitors of enkephalin-degrading enzymes. The present work shows the effects in vitro of imipramine and its active metabolite desipramine on the activities of two membrane-bound enkephalin-degrading aminopeptidases present in rat brain. Imipramine and desipramine in vitro do not affect the aminopeptidase M activity, but they reversibly inhibits the aminoeptidase MII. The enzyme kinetic analysis shows that this enzyme molecule has two different binding sites for each drug, which exert a mixed type enzyme inhibition.

Aminopeptidases↗
PubMed1997

New perspectives in the diagnosis of nosocomial pneumonia.

In the past decade, much has been learned about the diagnosis of nosocomial pneumonia. Most of these reports focused on evaluating the diagnostic reliability of different techniques and identifying an adequate gold standard. In the past year, the most outstanding studies focused on practical issues such as developing more rapid and less invasive diagnostic techniques and tools, simplifying previously standardized techniques, and searching for safer and more cost-effective procedures. Following the current trend, in the next few years we should spend more time learning about the impact of current techniques on outcome and less time looking for "El Dorado."

Cross Infection↗
PubMed1997

The value of routine microbial investigation in ventilator-associated pneumonia.

The use of microbiologic investigations in routine clinical practice, their value in guiding antibiotic prescription, and their influence on outcome were prospectively studied in 113 consecutive adults who developed ventilator-associated pneumonia (VAP). Blood cultures were performed in 78.7% of cases, protected specimen brushing in 95.5%, and bronchoalveolar lavage in only 45.1%. No causative agent was identified in 13 episodes (11.5%), and results of microbial tests directed a change in therapy in 43 (38.0%). Bronchoscopic results revealed inadequate initial selection of antibiotic therapy in 27 cases (23.9%) and led to a change in antibiotic treatment. Inadequate initial selection was still associated with a significantly greater increase in related mortality than adequate initial therapy (37.0% versus 15.4%, p < 0.05), although the change in therapy permitted clinical resolution in 17 (62.9%) of these 27 episodes, and 10 patients were discharged alive. Bronchoscopic results also permitted the reduction of the antibiotic spectrum in seven episodes (6.1%). This study suggests that in patients with VAP, bronchoscopic results are frequently associated with changes in antibiotic therapy. Nevertheless, our findings also emphasize the critical importance of an appropriate early antibiotic therapy.

Adult↗
PubMed1997

Risk factors for infection by Acinetobacter baumannii in intubated patients with nosocomial pneumonia.

STUDY OBJECTIVE: To investigate the epidemiology of infection by Acinetobacter baumannii in patients with ventilator-associated pneumonia (VAP). DESIGN: Prospective clinical study. SETTING: Three medical-surgical ICUs in teaching hospitals. PATIENTS: We followed up 707 mechanically ventilated patients and 148 episodes of VAP with etiologic diagnosis. RESULTS: A baumannii was isolated in 12 (8.1%) episodes in 148 patients. Five of these episodes were directly responsible for death. Using logistic regression analysis, the risk of VAP due to A baumannii was found to be high in patients with neurosurgery (odds ratio [OR]=10.03; 95% confidence interval [CI]=1.55 to 64.90), ARDS (OR=9.73; 95% CI=1.60 to 59.24), head trauma (OR=5.17; 95% CI=0.88 to 30.34), and large-volume pulmonary aspiration (OR=2.90; 95% CI=0.80 to 10.53). CONCLUSIONS: Intubated patients who develop pneumonia and have any of the above factors are at an increased risk of Acinetobacter infection.

Acinetobacter↗
PubMed1996

Identification of a fibronectin-like molecule on the surface of Leishmania amastigotes.

The major surface glycoprotein of Leishmania gp63, a fibronectin-like molecule, plays a key role in parasite-macrophage interaction. In this article, we describe a cross-reactivity between an anti-fibronectin monoclonal antibody and the amastigote gp63 by means of immunoelectron microscopy and immunoblot. Immunoreactivity was found on the amastigote membrane and in the flagellar pocket. We suggest that gp63 may play a role in the protection and/or nutrition process of the parasite in the phagolysosomes of the macrophage.

Animals↗
PubMed1996

Gas chromatographic determination of cholesterol and tocopherols in edible oils and fats with automatic removal of interfering triglycerides.

An automated gas chromatographic method for the simultaneous determination of cholesterol, alpha-tocopherol and alpha-tocopheryl acetate in edible oils and fats without derivatization is reported. Interferences from lipid material are avoided by using a continuous system to transesterify triglycerides with potassium methylate in methanol. The precision of the method is 1.9, 2.2 and 3.1% for cholesterol, alpha-tocopherol and alpha-tocopheryl acetate, respectively. The proposed methods was validated by analysing a standard reference material of coconut oil (SRM 1563-2) with good results. The method features a high throughput, minimal sample handling and analyte specificity (lipid material does not interfere).

Cholesterol↗
PubMed1996

A partially automated pretreatment module for routine analyses for seventeen non-steroid antiinflammatory drugs in race horses using gas chromatography/mass spectrometry.

A partially automated module for the routine determination of illicit non-steroid antiinflammatory drugs (NSAIDs) in biological fluids from race horses was built, tested, refined, and shown to work. This pretreatment module retains 17 NSAIDs on an Amberlite XAD-2 column before back-elution derivatization with methyl iodide in acetonitrile. Methylated derivatives are manually injected into a gas chromatograph connected to a mass spectrometer. The quantification limits thus achieved are 50-100 ng/mL in 1 mL of urine or plasma. The proposed method is more expeditious than its manual liquid-liquid and liquid-solid extraction counterparts and is similar in speed to a typical gas chromatographic program.

Animals↗
PubMed1996

Distribution of bursal secretory dendritic cells in the chicken.

BACKGROUND: The bursa of Fabricius provided the microenvironment for B-cell differentiation. Continuous contact between lymphoid cells and antigen in the bursa further suggested that antigenic material has an important influence on the maintenance and development of B cells in the bursa. In addition, a dendritic cell, the bursal secretory dendritic cell (BSDC), has been identified in the medulla. The hypothesis that, in the bursal follicles, the contact between the lymphoid cells and the antigen may be mediated by dendritic cells prompted us to identify a bursal dendritic cell that becomes activated after contact with the antigen. METHODS: A polyclonal antiserum to S-100 protein was used to identify bursal dendritic cells because S-100 protein, a calcium-binding protein, has been shown to be a marker for the identification of chicken dendritic cells following recent contact with antigen. RESULTS: At every age investigated, S-100-positive cells showed a location and shape identical to those described for BSDCs. Positive cells were found within and under the follicle-associated epithelial cells (FAE), indicating that these cells were strategically placed where they would encounter the antigen. In addition, positive cells were found arranged along the corticomedullary junction, which is a regenerative zone for the BSDC. After 10 weeks of age, the number of positive cells dramatically decreased, suggesting that the endocytic activity of the FAE may become impaired as the bursa regresses. CONCLUSIONS: The polyclonal antiserum to S-100 protein identified the BSDCs in the bursal follicles. Positive cells may be BSDCs that have undergone a functional activation after contact with the antigen. These cells may have a role as antigen-presenting cells in the bursal follicles. Hence, these cells may be involved in the events that lead to B-cell differentiation.

Age Factors↗
PubMed1996

An automated preconcentration-derivatization system for the determination of cocaine and its metabolites in urine and illicit cocaine samples by gas chromatography/mass spectrometry.

Although gas chromatography/mass spectrometry (GC/MS) is the most powerful technique for analysing cocaine and its hydrolysis products (benzoylecgonine, ecgonine methyl ester and ecgonine) in urine, the sample pretreatment required is rather laborious and involves a large number of steps. This paper reports a continuous method for the separation (based on the retention properties of cocaine and its major metabolites on a reversed phase C18 column), preconcentration (evaporation under nitrogen) and derivatization (collection of the residue in a few microlitres of derivatizing reagent) of cocaine and its metabolites in urine samples for subsequent analysis by GC/MS. Calibration graphs are linear from 5 to 3000 ng/mL; the detection limits are 1 ng/mL (cocaine and ecgonine methyl ester), 20 ng/mL (benzoylecgonine) and 200 ng/mL (ecgonine). The method was applied to illicit cocaine samples and to urine from a drug addict.

Autoanalysis↗
PubMed1996

Membrane-bound tyrosine aminopeptidase activities in the rat brain throughout the estrous cycle.

Puromycin sensitive and insensitive membrane-bound aminopeptidase activity levels during the estrous cycle in several brain areas have been described in this research. We have found the highest aminopeptidase M activity levels during the proetrous stage in the hypothalamus, the amygdala and the pituitary gland. Since this enzyme has been involved in opioid peptide metabolism, it is suggested that aminopeptidase M could play a part in the decrease in the inhibitory influence of the endogenous opioids peptides that participate in the LH surge.

Aminopeptidases↗
PubMed1996

Identification of a fibronectin-like molecule on Eimeria tenella.

The attachment of Eimeria tenella to its target cells as an obligatory intracellular pathogen is essential for the development of disease. Previous reports have established that other intracellular protozoa parasites have either fibronectin, an adhesion protein, or fibronectin receptors, both of which are involved in the interaction with the host cells. In this current research, studies have been undertaken to visualize a surface component that may be involved in the attachment of E. tenella to host cells. For this purpose, monoclonal antibodies, both anti-chicken and anti-human fibronectin, and also anti-chicken integrin were used. Our results show a fibronectin-like molecule with an apparent molecular weight of 110 kDa in mature schizonts and microgametes. Staining with serum directed against chicken integrin revealed immunoreactivity within mature schizonts. Both the fibronectin-like molecule and the integrin may play an important role in the parasite stage-cell interaction and the promotion of parasite uptake.

Animals↗
PubMed1996

[Efficacy and tolerance of the treatment of tuberculosis in the aged].

We analyzed 55 confirmed cases of tuberculosis in patients over 65, a sample that amounted to 9% of all patients seen in our practice over a period of 5 years. Mean age was 72.4 and the male/female ratio was 4/1. The most frequently associated diseases were tobacco addiction (49%), chronic obstructive pulmonary disease (33%), alcoholism (25%) and prior diagnosis of tuberculosis (20%). Lung involvement was the most common clinical presentation (76%), followed by pleural (9%) and skeletal (7%) involvement. The clinical picture was non specific, with 13% remaining asymptomatic. Cough was the most frequent symptom (45%) and unilateral apical fibrosis with ulceration was the most frequent radiological finding. Pleural discharge and cavitation were demonstrated in 14 and 22%, respectively. Scarring was visible on X-rays in 44%. The tuberculin test was positive in 88% of the cases in which it was performed. Mean delay in diagnosis was 3.4 months; 62% were diagnosed by sputum test, 11% by culture, and 27% histology. In 4% death was directly caused by tuberculosis. Three patients withdrew from treatment, in one case treatment failed, and there was one relapse detected at follow-up. We observed adverse side effects in 33%, and found no statistically significant differences between the 2 therapeutic protocols used (2 months RHS/7 months RH and 2 months RHZS/4 months RH). The incidence of tuberculosis among the elderly is low in our practice and the entity behaves much as it does in the rest of the adult population. Both the efficacy and tolerance of treatment can be considered optimal.

Adult↗
PubMed1996

[Pleural tuberculosis: analysis of 105 cases].

BACKGROUND: We present the results of a retrospective study with patients diagnosed of tuberculous pleuritis (TP) to offer a view and a perspective of this entity in our area. METHODS: We reviewed 105 cases of TP according to age, tuberculous risk factors, clinical onset, tuberculin test, chest roentgenogram, pleural fluid analysis (ADA, LDH, glucose and proteins) and pleural biopsy, and the evolution or sequels of the pleural effusion after a specific treatment. RESULTS: TP was a disease of younger patients (62% less than 30 years old) with tuberculous risk factors (34.3%), positive tuberculin test (81%) and an acute or subacute onset (88.5%). The pleural effusion was unilateral (98.1%), small-sized (61%), with pulmonary infiltrates in the 22.4%. All of the effusions were exudates with the exception of a transudative case. The levels of LDH, glucose and ADA were increased and the white cell counts below 6000/mm2, predominantly mononuclear. ADA was below 40 U/L in the 17% of cases. Pleural biopsy established the diagnosis in the 92.2% and the diagnosis was obtained in the 98.6% when we associated the analysis of ADA, pleural fluid and pleural biopsy. Specific treatment was accompanied with a good response. CONCLUSIONS: Our findings supported that TP maintained the predilection for younger patients with tuberculous risk factors. The clinical onset, radiographies, pleural fluid analysis and the utility of all diagnostic examinations were similar to other previous studies with the exception of few atypical cases. We confirmed a good prognosis with a correct treatment.

Adolescent↗