PubMed Health⌕ Search

Biomedical subjects

V Tirado

Publications and source records attributed to V Tirado.

5 recordsLinked to original sources
PubMed1991

Evaluating acrosome reaction steps with brightfield and differential interference contrast microscopy techniques.

Acrosomal integrity of bovine spermatozoa was evaluated using naphthol yellow S-erythrosine B stain with bright-field microscopy, .2% glutaraldehyde fixation with Nomarski optics, and live wet smears with Nomarski optics to compare the evaluation techniques. Four ejaculates per two Holstein bulls were enriched through a Percoll gradient, capacitated with heparin, and acrosome-reacted with lysophosphatidylcholine to prepare spermatozoa for in vitro fertilization. Spermatozoa samples were taken after each preparatory step, and percentage of intact acrosomes was evaluated with the stain, .2% glutaraldehyde, and live wet smear. Acrosomal integrity decreased with each preparatory step across all techniques. The decrease in integrity from heparin to lysophosphatidylcholine indicated that all methods detected the acrosome reaction. Technique means across preparation steps showed no differences. Correlations between microscopy techniques were high. The live wet smear used no fixation methods. Both the naphthol yellow S-erythrosine B stain and the .2% glutaraldehyde techniques employed fixation steps that may have introduced artifacts that could influence the data. The live wet smear evaluated by Nomarski optics allowed a comparable evaluation of the acrosome-reacted bovine spermatozoa. Comparing brightfield with differential interference contrast microscopy for detecting the acrosome reaction in bovine spermatozoa showed that both methods were equally accurate.

Acrosome↗
PubMed1990

Videomicroscopic comparison of bull sperm and leukocyte chromosome areas as related to gender.

Chromosomal areas from metaphase spreads of male bovine leukocytes were digitized and sex chromosomes identified using videomicroscopy. Autosomal areas were ranked in descending order within a cell and assigned to two categories based on alternating rank. X and Y chromosome areas were assigned to respective categories. Areas were divided by 4 to make their sum equivalent to sperm DNA content. Data were analyzed before and after inclusion of sex chromosomal areas. Before X and Y inclusion, rank contributed to difference in chromosomal areas. Rank by category interaction and category effects did not contribute to area variation. After X and Y inclusion, area variation was due to rank by category interaction, rank, and category. Differences between sums of chromosomal areas across categories was 3.57%. Head areas of morphologically normal sperm with intact acrosomes were digitized using the same optics as chromosomal areas. Sum of corrected chromosomal areas per category was used in discriminant analysis to assign sperm head areas to two categories with .5 prior probabilities. Assignment resulted in 1037 sperm in one category and 1177 in the other. Difference between largest sperm head area classes across categories was 3.2%. Discrimination of sperm head areas, based on sum of chromosomal area and measured with computerized videomicroscopy, may be used to evaluate sex of bovine spermatozoa.

Analysis of Variance↗
PubMedDate not supplied

[Pneuropsychological disorders after occupational exposure to mercury vapors in El Bagre (Antioquia, Colombia)].

INTRODUCTION: The department of Antioquia in Columbia is the main producer of gold in Columbia. In the gold-producing regions the population is exposed to high levels of mercury used in the processes of extraction and purification. Studies done in Columbia on neurotoxicity underline the hazards of mercury from the environmental and occupational-health point of view, but the effect of long-term exposure on cognitive function has not been studied. OBJECTIVE: To determine whether the miners of El Bagre (Antioquia, Columbia) have neuropsychological and/or behavior disorders as a result of occupational exposure to toxic mercury vapor. PATIENTS AND METHODS: The sample was made up of 22 right-handed men, residents of El Bagre, aged between 20 and 45 years old who had been exposed to mercury vapor for at least three years. The control group consisted of 22 men who lived in the non-mining regions of the department and had not been exposed to mercury, paired with the cases considered for age and educational status. Neuropsychological assessment, a medical examination and behavioral performance tests were applied to all the men (in both groups). RESULTS: In the study group alterations were seen and classified as: intellectual damage (mainly alteration of executive function and constructional praxis); emotional changes (symptoms of depression and anxiety) and neurological changes (amnesia, insomnia and tremor of the tongue). No changes were found in the control group. CONCLUSION: Exposure to mercury causes specific neuropsychological and behavior disorders in the absence of clinically detectable physical or physiological damage.

Adult↗
PubMedDate not supplied

[Performance of carriers and non-carriers of the E280A mutation for familial Alzheimer's disease in a naming test].

INTRODUCTION: Early preclinical diagnosis is the greatest challenge faced by researchers into dementia. Cognitive, neuroanatomical, neurophysiological and genetic markers have been reported. One of the preclinical cognitive markers is anomia and it is often assessed using visual naming tests. AIMS: The aim of this study was to analyse the type of mistakes made in a visual naming test in a group of carriers and non-carriers of the E280A PS1 mutation. PATIENTS AND METHODS: The sample was made up of 91 participants who were genotyped for the E280A PS1 mutation and divided into three groups: non-carriers (n = 30), asymptomatic carriers (n = 39) and sick carriers (n = 22). Selection was performed using the Minimental and the Fast and EDG scales and mistakes in the CERAD naming test were classified. The types of mistakes taken into account were: no answer, visual, semantic, phonological, the whole for the part, and not related. RESULTS: There is a significant difference in the number of semantic errors between non-carriers and asymptomatic carriers; on comparing the three groups, no statistically significant differences were found in visual mistakes. CONCLUSIONS: Visual mistakes are a general characteristic, even in healthy subjects and, therefore, these errors did not provide any information that could be used to classify patients with or without dementia. Semantic mistakes can be considered as being a preclinical sign in familial Alzheimer's disease (FAD). Both visual and auditory naming tests must be applied when evaluating patients with FAD.

Adult↗