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Biomedical subjects

M Gallego

Publications and source records attributed to M Gallego.

At least 19 recordsLinked to original sources
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↗
PubMed1995

Automatic gas chromatographic determination of the high-density-lipoprotein cholesterol and total cholesterol in serum.

A new analytical method that combines on-line precipitation-filtration, enzymatic hydrolysis, extraction and gas chromatography was developed for the determination of total cholesterol and high-density-lipoprotein cholesterol in human serum. Very-low-density lipoprotein, intermediate-density lipoprotein and low-density lipoprotein are precipitated with sodium phosphotungstate and magnesium chloride; then, the serum is continuously filtered and unprecipitated high-density-lipoprotein cholesterol is enzymatically hydrolyzed and finally determined as cholesterol by gas chromatography. Total cholesterol is also determined by direct introduction of the serum into the proposed system. The proposed method was validated by analyzing a lipid control serum with certified contents of high-density-lipoprotein cholesterol and total cholesterol. The results obtained were consistent with the certified contents.

Cholesterol↗
PubMed1995

Localization of splenic cells with antigen-transporting capability in the chicken.

BACKGROUND: The objective of the present study is to investigate the migration pattern of the splenic dendritic cell of the chicken named the ellipsoid-associated cell (EAC) from the site of initial location at the periphery of the ellipsoid to the splenic T- and B-dependent areas. METHODS: Bovine serum albumin bound to biotin and conjugated to gold particles was used as a histochemically identifiable antigen detected as a peroxidase reaction. The antigen was intravenously injected, and subsequently its pattern of distribution in a time sequence and within the tissue was examined at the light and electron microscopy levels. In addition, an hour prior to sacrifice, the chickens received a single injection of the thymidine analogue 5-bromo-2'-deoxyuridine, in order to quantify the number of DNA synthesizing cells and to establish a relationship between the migrating EAC and the rate of mitosis in the white pulp. RESULTS: The observations showed that between 12 hours and 3 days after the second antigen administration the labeled EAC, which was first located around the ellipsoid, progressively reached further areas with time towards the periarteriolar lymphoid sheaths, where newly formed germinal centers appeared. Furthermore, the rate of cell proliferation within the white pulp was associated with the arrival of the antigen-transporting EAC. CONCLUSIONS: The results suggest that migrating EAC have a role as both antigen-transporting cell and antigen-presenting cell in the T- and B-dependent areas, as a result of which migrating EAC is transiently found in periellipsoidal white pulp, then periarteriolar lymphoid sheaths, and finally germinal centers, where it may function as an interdigitating cell or as a follicular dendritic cell, depending on its location. Thus, we conclude that the EACs are precursors of both interdigitating and follicular dendritic cells.

Animals↗
PubMed1995

Ultrastructural identification of the splenic follicular dendritic cells in the chicken.

BACKGROUND: There is a need to identify the follicular dendritic cells (FDC) of the chicken spleen at the ultrastructural level during a secondary immune response. METHODS: The cells were identified after intravenous priming BSA and boosting with biotinylated BSA conjugated to colloidal gold particles. Monoclonal antibodies raised specifically either to chicken IgG or IgM were used to characterize these immune complex-trapping cells. RESULTS: The FDC had an irregular morphology which varied through time, supporting the existence of two types of FDC in the chicken spleen, one showing filiform cell processes, the other provided with beaded dendrites. When the filiform dendrites were observed, the FDC bound the antigen on their surfaces. These dendrites showed an intrincate convoluted configuration, forming tightly wrapped networks near the cell body. The networks had the same features as those described in mammals as antigen retaining reticulum (ARR). In chickens, the ARR, which represents sites of antigen localization on FDC, reached maximum development on day 5 after the second injection of BSA and had disappeared by day 8. At this time FDC had beaded dendrites. CONCLUSIONS: Antigen is retained on FDC in the chicken spleen for long periods of time.

Animals↗
PubMed1995

Antigen-binding cells in the cecal tonsil and Peyer's patches of the chicken after bovine serum albumin administration.

It has been previously reported in the chicken that the ellipsoid-associated cells (EAC), which are considered to be a type of splenic dendritic cell, migrate from the spleen into the blood after binding antigen on their surface. In the current study we traced the localization of these cells within two peripheral lymphoid organs, the cecal tonsil (CT) and the Peyer's patches (PP). The migration of the cells was followed by light microscopy using bovine serum albumin bound to biotin and conjugated to gold particles as a histochemically identifiable antigen detected as peroxidase reaction. The observations showed that the EAC after entering the circulating blood migrated into the lymphoid tissue of the CT and the PP. As a consequence, the antigen-binding cells were found in the diffuse lymphoid tissue and the germinal centers in both lymphoid organs. In the former location they were seen 24 h after the second antigen administration and in the germinal centers on Day 3. In addition, antigen-binding cells started to be observed in the lymphoid tissue at the same time as T and B cells were found to proliferate by using 5-bromo-2'-deoxyuridine. Based upon these findings, we suggested that the EAC have a role as antigen-transporting cells from the spleen to the CT and the PP via the blood stream. Furthermore, our results provided evidence that after the antigen-transporting EAC entered the above-mentioned organs, these cells behaved as antigen-presenting cells in both the T- and B-dependent areas.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Short report: detection of 72-75-kD and 123-kD fractions of Leishmania antigen in urine of patients with visceral leishmaniasis.

Two polypeptide fractions of 72-75 kD were detected in the urine of 14 of 15 patients with visceral leishmaniasis (VL) and another fraction of 123 kD was found in 10 of the 15 patients by using a Western blot technique. None of these fractions was detected in the urine of 20 controls. These results suggest that antigen detection in urine could be a powerful, noninvasive method for VL diagnosis.

Animals↗
PubMed1994

Sequential determination of triglycerides and free fatty acids in biological fluids by use of a continuous pretreatment module coupled to a gas chromatograph.

A continuous system coupled to a gas-liquid chromatograph was used for the sequential determination of triglycerides and free fatty acids in serum and urine. The module provides compositional information and hence more detailed information on lipid metabolism changes in patients suffering metabolic disorders. Lipids in biological samples are manually extracted in methanol-n-hexane and introduced into the flow system; free fatty acids are then separated by retention on an ion-exchange resin and triglycerides (not retained) are transesterified with acetyl chloride in methanol. The resulting methyl esters are continuously injected into the gas chromatograph and determined by using a flame ionization detector. In a second step, retained free fatty acids are eluted and derivatized (also with acetyl chloride in methanol) and subsequently determined similarly as the triglycerides. The proposed method was applied to the determination of triglycerides in a lipid control serum; free fatty acids were determined in a human pool serum by the proposed method and compared with the volumetric method used in clinical practice. The results obtained in both instances showed good agreement between the results provided for triglycerides and free fatty acids. The proposed method was also applied to urine samples; a parallel recovery study was also made in order to assess the performance of the method.

Automation↗
PubMed1994

Variant t(8;21) rearrangements in acute myeloblastic leukemia of childhood.

In a collaborative cytogenetic analysis of blast cells from 638 children with acute myeloid leukemia, 74 (11.6%) of the patients had the typical t(8;21)(q22;q22), while seven (1.1%) had complex variant translocations also involving 8q22 and 21q22 as well as a variable chromosome. In each case with a complex rearrangement, the myeloid leukemic cells contained Auer rods and were classified as M2 in the French-American-British (FAB) system. These seven children had a median age of 14 years (range, 7.3-18.9 years), a median initial leukocyte count of 9.1 x 10(9)/L (range, 2.5-142.2 x 10(9)/L), and have survived leukemia free for a median of 23 months (1-41 months) after attaining complete remission. The variable chromosomes in these seven cases--1, 2, 7, 12, 13, 15, and 17--appeared to be randomly involved. The clinico-biologic features of our cases with a variant t(8;21) are consistent with those of the published cases with the standard t(8;21), and support the hypothesis that the critical genetic alteration produced by the t(8;21) is located on the derivative 8.

Adolescent↗
PubMed1994

Determination of papaverine and cocaine by use of a precipitation system coupled on-line to an atomic absorption spectrometer.

A continuous-precipitation flame-atomization atomic absorption spectrometric method for the determination of papaverine and cocaine hydrochlorides is proposed. The method is based on the precipitation of reineckates by injection of Reinecke's salt into a carrier containing the alkaloids and their subsequent retention on a stainless steel filter. In this way, papaverine and cocaine hydrochlorides can be determine over the ranges 5-85 and 50-850 micrograms ml-1 with a relative standard deviation of 1.3 and 3.2%, respectively, and a sampling frequency of 150 h-1. The proposed method is more sensitive and selective for papaverine than it is for cocaine and can be applied to the determination of papaverine HCl in pharmaceutical preparations.

Chemical Precipitation↗
PubMed1994

Direct analysis of milk for aluminium using electrothermal atomic absorption spectrometry.

This work was conducted in order to develop a sensitive, precise method for the direct determination of aluminium in dairy products without sample pre-treatment. For this purpose, various chemical modifiers and thermal programmes for an electrothermal atomic absorption spectrometer were assessed. Different dry and wet sample pre-treatments were investigated in order to test the applicability of the method to the direct determination of aluminium in the matrices. Aluminium adsorption or leaching in various milk storage materials was also investigated. The proposed method allows the determination of aluminium in the range 5-50 micrograms l-1 and a detection limit of 0.32 micrograms l-1 for aluminium. The precision achieved, expressed as the relative standard deviation, was 5.6% for within-run assays (repeatability) and 12.7% for between-run assays (reproducibility). Various types of commercially available milk (skim, low fat and whole) and milkshake (marketed in different packages) were analysed after dilution to 1 + 3 (v/v) with 0.2% HNO3. Processing whole milk for drinking slightly decreases its aluminium content, but heating in aluminium vessels also slightly increases its content. The reliability of the entire procedure was confirmed by an analysis performed on a Standard Reference Material.

Aluminum↗