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Biomedical subjects

J Vilches

Publications and source records attributed to J Vilches.

At least 19 recordsLinked to original sources
PubMed1994

AgNOR and breast cancer. A study by image analysis.

The nucleolar organizer regions are used as a new marker in proliferation cell. AgNOR are loops of DNA actively transcribing to ribosomal RNA and they are associated with nonhistone proteins with strong argyrophil. In the present study we correlated the relationships between number and size of AgNOR measured by an automatic image analysis using CAS-100, in eleven breast carcinomas in different clinical stages and histological grades. We could identify the AgNOR with silver stain; the relationship between the number/size and histological grade/clinical stage shows that in normal breast we find one or two AgNOR but this number is larger when the carcinomas are less differentiated. When studied, the size is larger in the normal breast. We can make the same conclusions with the carcinomas which are lymph-node +.

Breast Neoplasms↗
PubMed1993

Effects of prolactin on explant cultures of rat ventral prostate: morphological and immunohistochemical study.

Specimens derived from rat ventral prostate were cultured by an explant culture technique using differents concentrations of ovine prolactin. Sacrificed explants embedded on paraffin were sectioned for morphologic and immunocytochemical studies using antibodies against prostatic acid phosphatase, prostatic specific antigen, and wide-spectrum monoclonal keratin. Prolactin significantly stimulated the growth of these cells in the concentration range of 1 x 10(-2) ui/ml, but was inhibitory at a concentration of 1 and 0.1 ui/ml. The 1 x 10(-3) and 1 x 10(-4) ui/ml prolactin concentrations demonstrated the preservation of a glandular epithelium with a columnar shape, similar to the normal appearance of ventral prostate from rats.

Acid Phosphatase↗
PubMed1992

[Evaluation of nuclear roundness as a tool for prostatic carcinoma grading].

The microscopic patterns adopted by prostate carcinomas are extraordinarily variable making its histopathological classification and grading extremely complicated. There are numerous systems for prostatic tumours' grading, but many of them lack a truly reproducible character and an acceptable degree of reliability; for this reason, we have studied a series of nuclear microscopic parameters, from a quantitative point of view, in a series of prostatic carcinomas with a minimum follow-up of five years. It was observed that of the morphometric values obtained--area, perimeter, projection on the X- and Y-axis as well as the nuclear roundness factor--the most useful and representative is the latter. Besides, this is an objective parameter to evaluate nuclear anaplasia and can also be considered as a prognostic factor since, in our series, those who died had a greater mean nuclear roundness factor than those who survived.

Aged↗
PubMed1992

[Embryonal development of interstitial Leydig cells in the rat testis].

Blood testosterone concentrations are not constant throughout life, there being a direct correlation with the numbers of cells producing that hormone, for which reason the existence of two Leydig's cells populations has been proposed: one foetal formation, which disappears just prior or immediately after birth, and a subsequent adult generation. In recent studies, however, that withdrawal has not been observed. Considering all the above, we have studied the evolution of these elements during the rat foetal period. From a morphological point of view Leydig's cells do not differentiate from those in the gonadal interstice until day 17 of pregnancy, showing a considerable increase in their numbers by day 21: while from that day onwards their numbers decrease they never disappear completely. We believe those cells become differentiated from the interstitial mesenchymal cells, and that their increase is facilitated by the proliferation of these same elements.

Animals↗
PubMed1992

[The nuclear roundness factor as a parameter in the anatomoclinical correlation of prostatic carcinoma].

This paper correlates the nuclear roundness factor to clinical stage, patient's age and acid phosphatase level at the time of diagnosis in a group of 48 patients with prostate carcinoma and a minimal follow-up of 5 years. It has been demonstrated that, from an anatomo-clinical point of view, the nuclear roundness factor is a good indicator because it presents increasing values as the clinical stage of tumoral extension worsens, and in those stages where the number of patients was relatively high the average of deaths was always higher than that of survivors. On the other hand, a direct correlation to total acid phosphatase, and an inverse correlation to age at the time of diagnosis was shown in patients with changes in these values.

Age Factors↗
PubMed1983

Bioelectrical tissue resistance during various methods of myocardial preservation.

Twenty-one mongrel dogs underwent cardiopulmonary bypass (CPB) and ischemic cardiac arrest for 60 minutes. The bioelectrical tissue impedance, water content, and ultrastructure of the myocardium were studied and correlated with various types of myocardial protection applied. The animals were divided into three groups according to the myocardial protection applied: Group 1, moderate general hypothermia; Group 2, moderate general and local hypothermia; Group 3, moderate general hypothermia and crystalloid cardioplegia. The hearts from 3 normal dogs served as controls. After 35 minutes of ischemic arrest, the difference in bioelectrical impedance of the myocardium of the left ventricle between Groups 1 and 2 was highly significant (p less than 0.001); in Groups 2 and 3, a significant difference was observed after 50 minutes. The heart water content in all three groups increased over that found in the hearts of the control animals, but there was no significant difference between Groups 2 and 3. There was evidence by ultramicroscopic study of ischemic damage to the myocardium in all of the experimental groups. Damage was less evident in Groups 2 and 3. We conclude that measurement of myocardial bioelectrical tissue resistance is a sensitive indicator of myocardial damage due to ischemia and may be useful clinically in determining the need for and type of cardiac resuscitation, particularly following CPB.

Animals↗
PubMed1982

SEM and X-ray microanalysis of human prostatic calculi.

Calculi removed from human prostates affected with nodular hyperplasia were analyzed with scanning electron microscopy and EDAX system. The general spectrum was made up of Na, Al, Mg, S, P, Ca and Zn. Two types of stone were identified morphostructurally and microanalytically: calculi type I of nodular surface with high peaks of S, and calculi type II polyfaceted with high peaks of P and Ca. Their formation from corpora amylacea and/or exogenous constituents is discussed. The superficial deposit of Zn suggests its incorporation from the prostatic liquid and does not seem to play an important role in the genesis.

Calculi↗
PubMed1980

Determination of plasma malondialdehyde-like material and its clinical application in stroke patients.

Plasma malondialdehyde-like material (MDA-LM) was evaluated in 138 normal subjects and in a group of 57 stroke patients using a modification of the method of Smith et al. (1976). The basal level of MDA-LM in the control group was 35 mumol/l with a range of 22-50 mumol/l. Values above 50 mumol/l were found in 80% of the patients suffering from subarachnoid haemorrhage, in 68% of those with cerebral thrombosis, and in 17% with transient ischaemic attacks. None of the patients with cerebral embolism, intracerebral haematoma, or lacunar infarct had values above 50 mumol/l. Significant statistical differences were found between the control group and all the patients except those with lacunar infarcts.

Cerebrovascular Disorders↗
PubMed1980

[Hepatocyte changes in experimental iron overloading. An ultrastructural and microanalytic study].

In this paper the ultrastructural changes in hepatocytes which were experimentally induced by oral and parenteral iron overloading in Sprague-Dawley rats fed on a steatogenous U.A.R. 2-13 diet are analysed. The changes in the mitochondria consisted of flocculation, vesiculation and crystolysis. The R.E.G. showed marked phenomena of dilatation degranulation and fragmentation. The lysosomes became more numerous and increased their content of ferric macromolecules. Degenerative nuclear phenomena were also seen. A microanalytic study of the cellular organelles and nucleus was done relating the cellular lesion and the intracellular distribution of the iron.

Animals↗