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J Cervera

Publications and source records attributed to J Cervera.

71 records · Page 4Linked to original sources
PubMed1983

Chromatin pattern of isolated human small thymocytes. A morphometric and stereologic study.

Human small thymocytes, isolated by the unit gravity velocity sedimentation technic, were analyzed in ultrathin sections to define their chromatin pattern using morphometric and stereologic methods. Condensed chromatin in these cells represents about 70% of the nuclear volume and, is distributed in peripheral (75%) and central clumps (25%). The analysis of the distribution pattern of these clumps shows that peripheral clumps are distributed more irregularly than central clumps with respect to both size and relative position. Comparison of these results with those previously described for human peripheral blood T lymphocytes shows significant differences, probably related to the different maturation states of the two cell types.

Blood Cells↗
PubMed1983

Nuclear alterations induced by cadmium chloride and L-canavanine in HeLa S3 cells. Accumulation of perichromatin granules.

The effects of L-canavanine and cadmium on the ribonucleoprotein constituents of HeLa S3 cells have been analyzed. Both chemicals induce a similar pattern of alterations in different RNP structures as well as in both RNA and protein synthesis. Pulse and chase autoradiographic experiments reveal that both canavanine and cadmium induce a preferential inhibition of nucleolar RNA synthesis and a slowdown in the transport or processing of nucleolar and extranucleolar RNA. Nucleoli become round and compact. Accumulation of perichromatin granules and fibrils occurs, there is a depletion of interchromatin fibrils, and nuclear formations appear which seem to be involved in the morphogenesis of perichromatin granules accumulated during the treatments. The appearance of clusters of 29- to 35-nm granules might be related with a deficient assembling of constituents of perichromatin granules. The effects of different inhibitors of the transcriptional processes on the accumulation of perichromatin granules suggest that these granules represent a particular subpopulation of hnRNP.

Autoradiography↗
PubMed1982

Extramedullary multiple myeloma. A qualitative and quantitative electron microscopic study.

A case of multiple myeloma with a mediastinal tumor and other unusual findings is described. The findings included the presence of extramedullary tumor masses at multiple sites in addition to the medullary tumor and, more interestingly, the occurrence of pleural and peritoneal effusions. The plasma cells from these effusions were analyzed using stereological morphometric methods. The plasma cells were also cultured and established as a continuous cell line and were studied using the same methods. Our results indicate that there are qualitative and quantitative morphologic differences between the pleural and peritoneal plasma cells. Comparison between plasma cells and cultured cells from the intraperitoneal exudate showed marked morphologic differences. The analysis of these differences indicated that mature plasma cells, when subjected to culture, were transformed into immature lymphoid cells.

Aged↗
PubMed1979

Alterations of the cell surface morphology in human T-rosetting lymphocytes. An ultrastructural study.

A study of E-rosette ultrathin sections has been undertaken in an attempt to analyze changes induced during the T-lymphocyte-sheep red blood cell interaction on the rosetted lymphocyte surface architecture. The formation of nonimmune rosettes implies different types of attachment between lymphocytes and sheep red blood cells which can affect the rosetted lymphocyte surface morphology: (a) Junctions not involving morphological changes which correspond to bands or point-to-point contact sites. (b) Junctions displaying localized morphological changes, which are revealed mainly in the form of microvilli or digitations. (c) Junctions involving broad morphological changes, revealed primarily by the development of various microvilli or other more complex structures. In both cases, the alterations are found only in those areas of the lymphocyte membrane-bound sheep red blood cells. The modifications that affect the rosetted lymphocyte make the validity of the E-rosette test questionable for studies aiming at the analysis of the lymphocyte surface architecture.

Animals↗
PubMed1978

Electron microscopic morphometric analysis of human T and B peripheral blood lymphocytes.

Using the system of morphometric analysis described in this paper, human peripheral blood T and B lymphocytes, labeled with specific surface markers, can be compared on different analytical levels. They show differences in their surface and the eccentricity of cells, in the relative surfaces occupied by peripheral and central condensed chromatin, in the average surface of the central chromatin clumps and in the number of perichromatin granules per nuclear surface. The morphometric analysis reveals the importance of examining the nuclear and the surface parameters in the characterization of lymphocytes, confirming that a detailed analysis of the nuclear characteristics can contribute to the identification of T and B lymphocytes by transmission electron microscopy.

Animals↗
PubMed1977

Sites of sulfatation in the chondrocytes of the articular cartilage of the rabbit. A study by quantitative radioautography of high resolution.

35S sulfate uptake by the articular cartilage chondrocytes, from biopsies of rabbit, have been studied by high resolution autoradiography. The Golgi apparatus, rough endoplasmic reticulum, cytosol, cytoplasmic membrane and extracellular space were considered as cell compartments in the quantitative analysis of the autoradiograms. The results obtained show: 1) a high activity of radiosotope incorporation in the Golgi apparatus; 2) a fast rhythm of transfer of the substances labelled in the Golgi apparatus to the cell membrane; 3) significant labelling of the rough endoplasmic reticulum, throughout the experiment. It is concluded: 1) The grains observed in the rough endoplasmic reticulum show a significant radioisotope uptake on this level, and this evidence some sulfotransferase activity. 2) The high 35S sulfate uptake level which is observed in the Golgi apparatus demonstrates that the highest sulfotransferase enzyme activity is located in this cell area, thus showing that the "early" sulfation that began in the rough endoplasmic reticulum was completed by a "late" sulfation in the Golgi apparatus. It is here that complete chondromucoprotein building takes place before being excreted. 3) The high transfer level of the labelled substances from the Golgi apparatus shows that the sulfated product secretion for building the cartilage matrix takes place rapidly since a great label increase can be already observed at the beginning of the chase period in the outer surrounding area of the chondrocyte membrane.

Animals↗
PubMedDate not supplied

Role of angiotensin II in the antinatriuresis that follows acute volume depletion.

The aim of this study was to examine the contribution of the renin angiotensin system to the antinatriuresis that follows acute volume depletion. Four groups of six dogs each were studied. The first group was exposed to saline expansion (8% body weight) (SE). The second group was exposed to acute volume depletion (2% body weight) followed in one hour by saline expansion (AVD). The third and fourth groups were similar but in dogs treated with high doses of captopril (SE + C and AVD + C). Dogs were anesthetized with phenobarbital. Control measurements were made for 30 minutes before and 60 minutes during saline expansion. Glomerular filtration rate (inulin), renal blood flow (para-aminohippuric acid) and mean arterial pressure were similar in the four groups during the experiment. The increase in fractional sodium excretion from the control period to the end of saline expansion was in the SE group from 0.6 +/- 0.2 to 6.4 +/- 1% and in the SE + C group from 1.1 +/- 0.3 to 8.5 +/- 1.3%. In contrast, in the AVD group it only rose from 0.8 +/- 0.2 to 3.5 +/- 0.7% and in the AVD + C group from 1.3 +/- 0.4 to 4.1 +/- 0.6%. Therefore, the increment in sodium excretion during saline expansion was significantly lower in dogs exposed to acute volume depletion, independent of the treatment with captopril. The blunted natriuresis cannot be explained by differences in GFR, RBF or MAP. These results suggest that renin angiotensin system is not the responsible agent of the sodium retention that follows acute volume depletion.

Acute Disease↗
PubMedDate not supplied

[Hepatic biopsy in acute leukemia].

In 25 patients with acute leukemia that presented chantes in liver function tests, 29 liver biopsies were done by percutaneous needle or peritoneoscopy and directed needle, to determine the nature of the lesion. In one case leukemic infiltration was found; 16 patients showed nonspecific lesions, one, granulomatous hepatitis, one, viral hepatitis; one showed no changes in the biopsy. In these twenty cases the treatment was not modified, the survival time was from 15 to 57 months (median 25 months), and 14 an still in remission. Five patients (20%) showed drug-induced hepatitis; in these it was necessary to modify to chemotherapy, the survival time in four cases was 2 to 9.6 months (median 4.8 months) and one is still in remission after 36 months of treatment. It is concluded that hepatic biopsy may be very useful in evaluating the undesirable effects of treatment of acute leukemia and in making therapeutic decisions. The risks of this procedure and the contraindications are similar in patients with acute leukemia and those with other diseases.

Acute Disease↗