Search PubMed⌕ Search

Biomedical subjects

L Alvarez

Publications and source records attributed to L Alvarez.

288 records · Page 16Linked to original sources
PubMedDate not supplied

A simple and economic slide micro-immunoenzymatic (micro-SIA) test for epidemiological studies of toxoplasmosis.

A slide micro-immunoenzymatic assay (micro-SIA) to detect antibodies to non-particulate Toxoplasma gondii antigens is described. This assay allows the diagnosis of toxoplasmosis infection in about 1 hr. Twenty-four determinations can be performed per slide. Five hundred ng of antigen and 5 or 10 microliters drop of each reactive are necessary per well. The clear contrast of colours obtained for negative and positive sera after the test is finished, allows direct discrimination of the results. However, it is possible to quantify the results of the reaction using a minireader. Sera dilution cutoff value, determined as the most frequent titre for the general population, is 1:100. The toxoplasma micro-SIA correlates well with indirect immunofluorescence (IIF), its sensitivity is at least three times as much as IIF. The test has an intra and inter assay variation coefficient of 5.46% and of 6.24% respectively. Sera obtained at random from argentinian people were analyzed and a 56% of infection was found. The main features of the Toxoplasma micro-SIA are its simplicity, sensitivity, reproducibility, and the virtual absence of background making it very suitable for screening tests.

Animals↗
PubMedDate not supplied

Developmental toxicity of dimethyl sulfate by inhalation in the rat.

Dimethyl sulfate (DMS; CAS No. 77-78) is a colorless, oily liquid which is used as a chemical intermediate and as a reactant in producing polyurethane resins. In this study, groups of pregnant Crl:CD BR rats were exposed, nose-only, to either 0.1, 0.7 or 1.5 ppm DMS by inhalation for 6 hr/day from Days 7 through 16 of gestation (day in which copulation plug was detected was designated Day 1G). A control group of pregnant rats was exposed simultaneously to air only. All female rats were euthanized on Day 22G and the fetuses were examined. A suppression of both food consumption and the rate of body weight gain was seen in the 0.7 and 1.5 ppm groups. No unusual clinical signs were seen in rats exposed to DMS. None of the reproductive parameters was altered in any of the groups and no statistically significant fetal effects were detected. DMS is not a developmental toxin in the rat following inhalation exposures up to 1.5 ppm during the period of major organogenesis.

Administration, Inhalation↗
PubMedDate not supplied

Orf: case report and literature review.

Ecthyma contagiosum, or orf, is an uncommon dermatosis resulting from cutaneous infection with sheep pox virus. It is generally a benign and self-limited condition. Early clinical recognition is paramount to avoid unnecessary surgical intervention or extensive diagnostic workup. Diagnosis is usually based on a clinically typical skin lesion, characteristic histology, and a history of sheep exposure. We report the case of an infected sheep farmer and review the literature.

Adult↗
PubMedDate not supplied

[Choledochal cyst].

Explore the source record for details and available documents.

Adolescent↗
PubMedDate not supplied

[Atypical regenerative changes, dysplasia, and carcinoma in situ in chronic gastritis associated with Helicobacter pylori].

In the present work we study the association between chronic active gastritis (CAG), atypical regeneration and dysplasia and gastric Helicobacter pylori (HP) infection. We study two groups of endoscopic biopsies. Regenerative changes and dysplasia were evaluated according to Gandur-Maymneh et al. classification which was simplified in typical and atypical regeneration, and mild and severe dysplasia. The group I included 94 patients with CAG, 9 with chronic non active gastritis (CNAG) and 2 with normal gastric mucosa. CAG was graded according to activity in; severe 28 patients; moderate 54 patients and; mild 12 patients. HP association in these cases was 100%, 77% and 25%. In cases of CNAG HP was present in 22%, there were not HP in normal gastric mucosa. There were atypical regeneration in 25% of moderate CAG and in 42% of severe CAG. Mild dysplasia was present in 7.5 and 25% in cases of moderate and severe CAG. Two biopsies showed severe dysplasia. In addition, intestinal metaplasia was found in 15% of CAG, the metaplasia was present in 25% of cases with CAG and atypical regeneration; in 54% of cases with mild dysplasia and; in 100% on cases with severe dysplasia. The group II included 9 cases of gastric cancer of intestinal type, 7 cases of diffuse type, and 4 cases of mixed type. In all these cases there was viewed CAG associated to HP infection in non-neoplastic mucosa. In 75% of cases there were showed atypical regeneration and 60% presented some type of dysplasia. There was transition between atypical regeneration and dysplasia in 6 cases of intestinal gastric cancer and in 3 cases of mixed type. We found relationship between the intensity of CAG and HP colonization, and the association with atypical regeneration and dysplasia.

Adult↗
PubMedDate not supplied

Genetic changes at the beta-2-adrenergic receptor locus on chromosome 5 in human colorectal carcinomas.

Matched normal/tumor DNA pairs from 44 colorectal carcinoma patients were examined for tumor-specific genetic changes using a probe for the beta-2-adrenergic receptor (ADRB2R) gene on chromosome 5. This locus (5q31-q32) maps close to the site of chromosomal deletions recently reported to occur in colorectal carcinomas and distal to the chromosomal location of the familial adenomatous polyposis (FAP) gene (5q21-q22). Our investigation shows tumor-specific allele loss or allelic rearrangement of at least 29% at the AdRb2R locus on chromosome 5 in informative cases. These results suggest that the mechanism by which colorectal carcinomas lose genetic material on chromosome 5 can affect this functional gene located distally to the FAP gene. The possible functional significance that ADRB2R gene changes may have in neoplastic progression is discussed.

Adenomatous Polyposis Coli↗
PubMedDate not supplied

[Thrombosis from prosthetic materials: prevention with different antiaggregatory agents. Low dose aspirin?].

Using an ex vivo shunt in dogs, platelet deposition on 6 prosthetic materials used in the construction of cardiovascular prostheses [highly porous Knitted Dacron (intervascular HP 800, 1,400 ml/cm2/min/120 mmHg), Woven Dacron of low porosity (intervascular LP 200, 200 ml/cm2/min/120 mmHg), Doble Velour Knitted Dacron, Avcothane 51 elastomere and the mesothelial and epipericardial surfaces of bovine pericardium] was quantified. The study of the prevention of platelet thrombi formation on these materials was carried out in 6 groups of 8 animals: group 1 (control), group 2 (5 mg/kg body weight/day acetylsalicylic acid), group 3 (20 mg/kg body weight/day acetylsalicylic acid), group 4 (15 mg/kg body wt/day triflusal plus 5 mg/kg body wt/day dipyridamole), group 5 (15 mg/kg body wt/day triflusal) and group 6 (5 mg/kg body wt/day acetylsalicylic acid plus 5 mg/kg body wt/day dipyridamole). Platelets were labeled with 111In-oxine. The least thrombogenic material was Avcothane 51 elastomere. The only effective treatment for reduction of platelet deposition on the 6 materials was that used in group 2. The treatment used in group 3 only decreased the deposition of platelets on 3 of the 6 materials. The treatments employed in groups 4, 5 and 6 did not significantly diminish the deposition of platelets on any of the materials when compared with the control group. The platelet count was not modified in the animals in groups 2 and 4 while in the rest it decreased after the test.

Animals↗
PubMedDate not supplied

Effects of different doses of acetylsalicylic acid on platelet aggregation: an experimental study of prosthetic materials in dogs.

Laminar flow is the condition best suited to the study of platelet thrombi. This type of thrombus is predominant in arteries, in the tubes of cannulas used in artificial circulatory systems, in cardiac valve prostheses and in prosthetic arterial implants. Antiplatelet drugs could, in these cases, reduce the extent of thrombus formation. At present the optimal dose of acetylsalicylic acid (ASA) to achieve the best antithrombotic effect is unknown; some papers show that high doses augment experimental thrombosis. By means of autologous platelets labelled with 111In-oxine, we have quantified the accumulation on different materials used in cardiovascular surgery (woven, knitted and double velour Dacron, Avcothane 51 elastomere and smooth surface and rough surface pericardium). Samples of these fabrics were placed in a laminar flow chamber connected between the right atrium and femoral artery of the experimental animals (dogs). The animals were divided into four groups of eight dogs: Group I: no treatment Group II: animals treated one week earlier with ASA (1 mg/kg/day) Group III: as in Group II, but at a dose of 5 mg/kg/day Group IV: as in Group II, but at a dose of 20 mg/kg/day. The materials upon which the least amount of platelets were accumulated were the smooth, epicardial surface of pericardium (SP) and Avcothane (AV). The least deposition was produced in Group III, with the exception of SP. In the case of this material, there was no difference between Groups I and III. In Group IV, the deposit was greater with respect to the untreated group (Group I), except in the case of AV, in which there was no difference between Groups I and IV.

Animals↗
PubMedDate not supplied

Design of a laminar flow chamber to study platelet aggregation.

The growing importance of the utilization of artificial materials in cardiovascular surgery makes it necessary to know their thrombogenic capacity. Our flow chamber, which is constructed of methacrylate, is capable of providing a laminar flow. The chamber itself consists of the trunks of two cones, one for the inflow and the other for the outflow, which are joined at their widest point to the ends of a cylinder of the same diameter. In the interior of the cylinder, which constitutes the central part of the system, are placed three rectangular fragments of the material to be studied. The vertices of the trunks of the cones allow the coupling of two flexible siliconized tubes in such a way that the system can be utilized in an "ex vivo' experimental model, constituting a bridge between the femoral artery and the right atrium of a large experimental animal, as well as in vitro, coupled to a continuous perfusion pump. The advantages provided by this system are that: (a) three materials can be studied simultaneously in an identical situation, (b) it is possible to submit these materials to conditions similar to those that give rise to platelet thrombi, and (c) it is possible to quantify the aggregation on each material by labelling the platelets with 111In-oxine.

Biocompatible Materials↗
PubMedDate not supplied

Radiologic study of patellar height in Osgood-Schlatter disease.

There are contradictory reports regarding patellar position in the Osgood-Schlatter disease. We present a prospective statistical study of 17 patients with Osgood-Schlatter disease and 12 adolescents without anterior knee pain. The Caton-Deschamps index was assessed on strictly the lateral radiograph of the knee. The findings indicate a strong association between Osgood-Schlatter disease and patella alta. This increase in patellar height would require an increase in the force needed from the quadriceps to achieve full extension. This mechanism could be responsible for the apophyseal lesion.

Adolescent↗
PubMedDate not supplied

Chondrolysis of the hip after transfer of the greater trochanter.

Transfer of the greater trochanter is a surgical technique that is used for overgrowth of the greater trochanter arising from disturbance of the growth plate of the proximal femur. Few complications have been described, and to our knowledge, necrosis of the cartilage has not been reported. Herein we describe four cases of chondrolysis in three patients who underwent this surgical procedure. In our view, immobilization with plaster associated with the increased pressure produced by the descent of the gluteal attachment may have contributed to the development of chondrolysis.

Adolescent↗
PubMedDate not supplied

[Comparative study of secretory IgA].

OBJECTIVE: The aim of this study was measure and compare Secretory IgA levels in the respiratory tract. DESIGN: Cross-sectional study. SETTING: Neumology Department of General Hospital. La Raza Medical Center Mexico. MATERIAL AND METHOD: There were 35 volunteers. Samples of sputum, washings nasopharyngeal and bronchial was obtained from thirty five patients with COPD. Measurement of SIgA levels was performed by nephelometric technique. Results is reported as ratio of SIgA concentration/Total proteins concentration named SIgA relative concentration. Correlation index was obtained of three type of samples. RESULTS: The SIgA values of sputum, washings nasopharyngeal and bronchial was similar similar +/- 0.011, 0.064 +/- 0.007 and 0.082 +/- 0.017 respectively). Multiple correlation was r = 0.508 (p < 0.01).

Adolescent↗