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Biomedical subjects

L Vidal

Publications and source records attributed to L Vidal.

15 recordsLinked to original sources
PubMed1992

Application of morphometric methods to the cytologic study of intradermal nevi.

Twenty-one intradermal nevi were studied by morphometric methods in an attempt to morphologically characterize the two types of nevus cell--epithelioids, type A, and fusiforms, type C--and to quantify the differences between them. Morphometric parameters of the intradermal nevi were compared with similar parameters of melanocytes and melanoma cells so that the maturation rates of the nevi cells could be established and to see if the parameters might indicate the degree of malignancy. Superficial nevus cells were differentiated from deep cells by their larger size and larger nuclear area. Nuclear area appeared to have potential for differentiating benign from malignant tumors. Decrease in cellular area appeared to indicate maturation rather than atrophy. Melanoma cells were differentiated by their larger size. Cell nuclear perimeter appeared to have confirmatory value, while cell perimeter was inconclusive.

Biopsy↗
PubMed1992

[Acquired cystic renal disease. Association with hypernephroma].

Emergence of multiple bilateral renal cysts observed in patients undergoing periodic haemodialysis is 40%. The pathology, known as Acquired Cystic Renal Disease (A.C.R.D.) presents a high association to renal cancer. Two cases of A.C.R.D. and their association with hypernephroma, one resulting in secondary retroperitoneal haemorrhage and the other in intracystic haemorrhage, are presented. Forms and diagnosis are analyzed, insisting upon the need of monitoring the patients in haemodialysis from the point of view of tumour emergence.

Aged↗
PubMed1991

Histoenzymatic study of the neurons in the visual sector of the thalamic reticular nucleus in the adult rat.

The different types of neurons within the visual sector of the rat's thalamic reticular nucleus were studied, both in terms of their morphology and their histochemical activity. Neurons were classified according to their dendritic arrangement into bitufted and multipolar. On the basis of the somal shape, bitufted neurons were further subdivided into two types, triangular and fusiform, and multipolar neurons into stellate and ovoid. Bitufted neurons have moderate succinic dehydrogenase (SDH) activity, while multipolar neurons usually have high SDH activity. Finally, the location of neurons in the visual sector of the thalamic reticular nucleus was described.

Animals↗
PubMed1990

Incidence and features of liver disease in patients on chronic hemodialysis.

We examined the incidence and features of liver disease and the presence of serologic markers of hepatitis B virus (HBV) infection in 134 patients on hemodialysis for 2 to 14 years. Twenty-three patients (17%) had had a single episode of acute hepatitis while on dialysis and two patients had had two episodes, which were attributed to infection by hepatitis B virus in 7 instances and by hepatitis non-A, non-B virus in 20. Chronicity supervened in 4 cases of hepatitis B (57%) and in 14 cases of hepatitis non-A, non-B (70%). A prolonged rise of serum aminotransferases, which was not preceded by acute hepatitis, was detected in 23 additional patients (17%). Acute hepatitis and prolonged hypertransaminasemia were more frequent in patients dialyzed at a hospital unit than in patients dialyzed outside the hospital or at home. These observations indicate that development of acute and chronic liver disease, mainly hepatitis non-A, non-B, is frequent in patients on chronic hemodialysis, particularly in those dialyzed in hospital. Serologic evidence of current or past infection by HBV was detected in 57 patients (42%) with sustained positivity of HBV serum markers. Transient positivity for anti-HBc, anti-HBs, or both, possibly related to passive transmission of antibodies by blood transfusion, was observed in 20 patients (15%). These findings indicate that periodic, repeated testing for HBV serum markers is necessary only in a minority of patients on long-term hemodialysis.

Acute Disease↗
PubMed1989

[Ascites and pleural effusion. Study and follow-up of 79 patients].

We reviewed 79 patients with a picture of pleural effusion (EP) and ascites, who represented 8% of a total of 982 pleural effusions studied. Liver cirrhosis (CH), 37 cases (47%), disseminated carcinomatosis, 31 cases (39.5%), and congestive heart failure, 6 cases (7%), were the main causes. We made two groups of liver cirrhosis: A) liver cirrhosis with hydropic decompensation, 12 patients (15%), and B) liver cirrhosis with an additional complication added to the above, 25 patients (31.5%), this being infectious in 88% of the cases. In the B group there were cases of left hydrothorax, more features of effusion and a lower survival at 3 months of follow-up than in tha A group. Effusions of neoplastic origin were most frequently seen in tumors of the ovary, digestive system, lymphomas and undetermined origin. In malignant effusions, the cytology was positive in pleura in 60% and in ascites in 55%. Twenty percent of peritoneal fluids and 47% of pleural effusions were serohemorrhagic and 100% and 88%, respectively, were of exudative nature. In liver cirrhosis the ascites was serofibrinous and transudated (100% in group A and 85.5% in B) and the pleural effusion was a serofibrinous transudate except in the cases in which there was an added infection. We confirm the ominous prognosis of the coexistence of pleural effusion and ascites.

Adult↗
PubMed1989

Quantitative study of the dorsal lateral geniculate nucleus of the rat during the postnatal development.

The chronology of dLGN development was studied in the rat from birth to 90 days postnatal (dpn). Our results indicate the faster dLGN growth occurs from 1 dpn to 21 dpn. The neuronal number and density was calculated. No significant neuronal loss was detected in the period investigated but the present study shows evidence of an important decrease (of 75%) in the neuronal density between 7 dpn and 21 dpn. Immediately the study of neuronal sizes and shapes was undertaken. Approximately at 14 dpn the deep neurons get a size significantly bigger than the marginal neurons. Finally, the different neuronal sizes were used for determining the successive phases of the neuronal development.

Aging↗
PubMed1977

Nature of the genetic determinant controlling encapsulation in Staphylococcus aureus Smith.

Two strains of Staphylococcus aureus, Smith and M, were studied for the elimination of encapsulation. For S. aureus M, encapsulation was stable. For S. aureus Smith, spontaneous loss of encapsulation was 1.3% and increased markedly in medium containing surface-active agents. In the presence of sodium dodecyl sulfate, unencapsulated cells had a considerable selective advantage. Attempts to demonstrate covalently closed circular plasmid deoxyribonucleic acid were unsuccessful. In cultures of unencapsulated cells, encapsulated cells were observed occasionally. These data argue against a plasmid location for the determinants controlling encapsulation in this organism in spite of a high spontaneous loss of this character.

Chromosomes, Bacterial↗
PubMed1976

Location of the coagulase gene in Staphylococcus aureus.

Evidence is presented for the chromosomal location of the coagulase determinant in most strains of Staphylococcus aureus. By the use of a pour-plate technique, transduction of the capacity to produce coagulase to a coagulase-negative mutant of S. aureus was studied. The frequencies of transduction were low unless the transducing phage was exposed to ultraviolet irradiation and the recipient was lysogenised with the transducing phage. Attempts to transfer the coagulase gene from S. aureus to S. epidermidis were not successful.

Coagulase↗