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Biomedical subjects

E Rocha

Publications and source records attributed to E Rocha.

At least 109 records · Page 6Linked to original sources
PubMed1993

[Association of polycythemia vera and multiple myeloma. Presentation ofa new case and review of the literature].

We present a patient diagnosed of polycythemia vera who developed a multiple myeloma 13 years after the initial diagnosis of polycythemia vera. Although an unusual finding, another 17 patients with polycythemia and myeloma have been described. In some patients the diagnosis of both diseases was simultaneous but in most cases myeloma developed years after polycythemia vera. Some patients received only venipuncture for treatment of polycythemia vera so the appearance of multiple myeloma could not be explained on the grounds of chemotherapy induced second neoplasm. An explanation for this association is suggested.

Aged↗
PubMed1992

Fibrinolytic potential and antiphospholipid antibodies in systemic lupus erythematosus and other connective tissue disorders.

We studied the fibrinolytic response before and after venous occlusion (VO) in 30 patients with systemic lupus erythematosus (SLE), 25 with rheumatoid arthritis (RA) and 25 with different connective tissue disorders. Results were compared in patients with and without antiphospholipid antibodies (APA) and a history of either thrombosis or abortions. Before occlusion plasma levels of tissue-type plasminogen activator (t-PA) antigen and its inhibitor (PAI-1) were significantly higher in the patient group (p < 0.001). After occlusion, a low fibrinolytic activity on fibrin plates (p < 0.005) was observed in the same group. t-PA capacity and t-PA release were similar in relation to controls. The plasma PAI-1 activity was significantly elevated in each group of patients (p < 0.005) as compared to the control group. No significant differences with respect to t-PA and PAI-1 were observed in patients as to the presence or absence of thrombosis. There was also no correlation between the fibrinolytic changes and the presence of APA. It is concluded that an impairment of the fibrinolytic system, mainly related to increased PAI-1 levels, is present in most patients with connective tissue disorders, although these changes did not correlate with the presence of APA or the incidence of thrombosis.

Adult↗
PubMed1992

Effect of DDAVP on endotoxin-induced intravascular coagulation in rabbits.

We have evaluated the effect of 1-Deamino-8D-arginine vasopressin (DDAVP) on an experimental model of intravascular coagulation (DIC) induced in rabbits by injection of 20 micrograms kg-1 h-1 during 6 h of E. coli lipopolysaccharide. DDAVP significantly ameliorated the platelet drop and fibrinogen decrease (p less than 0.01) induced by endotoxin in control animals. A significant reduction in factor XII consumption (p less than 0.01) and a decrease in the generation of endotoxin induced PAI-1 activity in rabbits circulation was also observed (p less than 0.005). Moreover, fibrin deposition in kidneys of rabbits receiving DDAVP was significantly reduced as compared to control animals. Finally, the mortality rate in the control group was significantly higher than in DDAVP-treated rabbits (p less than 0.01). The hemostatic changes induced by DDAVP correlated with lower fibrin deposition and reduction in mortality rates.

Animals↗
PubMed1992

A new case of acute lymphoblastic leukemia B-cell type with chromosomal rearrangements involving the T-cell receptor breakpoint at band 14q11.

A patient with B-cell acute lymphoblastic leukemia (ALL) and a translocation t(8;14) (q24;q11) is described. Translocation t(8;14)(q24;q32) is commonly associated with B-cell leukemia; nevertheless, translocations affecting chromosome 14 at band q11 are associated with T-cell malignancies, since the locus 14q11 contains genes that encode for the alpha and delta chains of the T-cell receptor (TCR). This finding points to the idea that the association between 14q11 rearrangements and T-cell neoplasia is less than complete.

Adult↗
PubMed1992

Ultrastructural qualitative and quantitative data on the sporogenesis of the protozoan Abelspora portucalensis (Microspora, Abelsporidae): a different approach to the study of microsporidia.

The sporogenesis of the microsporidium Abelspora portucalensis was studied with electron microscopy. In qualitative terms, new aspects of the cytoplasmic ultrastructure of the schizont, sporont, and sporoblast are described: the presence of microtubules, of aggregates of small opaque vesicles, and of dispersed larger vesicles with clear matrix. The hypothesis that the opaque vesicles may represent the Golgi apparatus and the clear vesicles may correspond to the smooth endoplasmic reticulum is discussed. The use of standard stereological and statistical techniques gives us a new perspective on the development of this microsporidium. The most relevant quantitative data display that the amount of rough endoplasmic reticulum (either in relative or absolute terms) presents significant differences among the three stages, with the sporont showing the highest values; that the absolute (but not the relative) volume of the large vesicles significantly changes during sporogenesis with the highest values presented by the sporont; that the surface-to-volume ratio of the schizont and sporont cells is similar and significantly greater than that of the sporoblast cell; that the surface density of the nucleus in relation to soma remains constant in the three stages (on the contrary, the surface-to-volume ratio of the nucleus increases and its volumetric density diminishes); and finally, that the nucleolus decreases its relative and absolute volumes. The functional significance of these results is analyzed and the application of similar methodology in quantifying the effects of drugs upon microsporidia is suggested.

Animals↗
PubMed1992

Coexistence of essential thrombocythemia and multiple myeloma.

We describe a patient with essential thrombocythemia (ET) who developed multiple myeloma (MM) 5 years after the initial diagnosis. A review of the literature revealed no additional reports of the association of these two diseases. Development of MM was not related to treatment of essential thrombocythemia. This association suggests an alteration at the pluripotential stem cell level.

Aged↗
PubMed1992

Sequence changes in the live attenuated, cold-adapted variants of influenza A/Leningrad/134/57 (H2N2) virus.

Nucleotide sequences were determined for the RNA segments coding for proteins other than the hemagglutinin and neuraminidase of the A/Leningrad/134/57 (H2N2) wild-type (A/Len/wt) virus and its two cold-adapted (ca) and attenuated variants, A/Leningrad/134/17/57 (A/Len/17/ca) and A/Leningrad/134/47/57 (A/Len/47/ca) that are used in the U.S.S.R. in the preparation of reassortant live attenuated vaccines. Ten nucleotide differences were detected between the sequences of the A/Len/wt and A/Len/17/ca viruses; of these, eight were deduced to encode amino acid (aa) substitutions. One aa substitution each was predicted for the PB2, M1, M2, and NS2 proteins, whereas two aa substitutions each were predicted for the PB1, and PA proteins of the A/Len/17/ca virus. Four additional nucleotide changes were found in the genome of the A/Len/47/ca virus; three of these were detected to code for one additional aa substitution each for the PB2, PB1, and NP proteins.

Amino Acid Sequence↗
PubMed1992

Quantitative age-related changes on nuclear invaginations of neocerebellar Purkinje cells.

The aim of this study was to provide stereological data for seeking whether Purkinje neurones increase their nuclear envelope invaginations with age. The nuclear parameters considered were: ratio of absolute surface area to volume, surface density and absolute surface area. The first two parameters did not significantly change, but the absolute surface area exhibited marked variations. Regression studies showed no significant linear correlations between any of the parameters and age; so, the increase in number and/or in depth of the invaginations was not suggested. The association of invaginations with a nuclear cap of Nissl substance is a constant feature, stressing that the physiological importance of the complex is maintained throughout the ageing process.

Aging↗
PubMed1992

Generation of a subtype-specific neutralization epitope in foot-and-mouth disease virus of a different subtype.

An epitope involved in neutralization of foot-and-mouth disease virus (FMDV) of subtype C3 was generated by a single amino acid replacement in VP1 of FMDV of subtype C1. The replacement [Ser (139)----Ile, in the immunodominant site A] was consistently found in those FMDV C1 Santa Pau-Sp/70 mutants resistant to neutralization by monoclonal antibody (MAb) SD6 (specific for most C1 viruses) that acquired the capacity to be neutralized by MAb 7AB5 (specific for C3 viruses).

Amino Acid Sequence↗
PubMed1992

Are Ranvier's nodes of the central nervous system also artifacts by preparation?

Recent research on peripheral nerves of six species of vertebrates concluded that Ranvier's nodes may be artifacts by preparation. As a consequence, the question as to whether or not Ranvier's nodes of the central nervous system may also be artifacts was logically raised. The ultrastructural data concerning our field of research (the cerebellar cortex) support the notion that Ranvier's nodes are real features in the central nervous system; otherwise, the occurrence of vesicular outpockets establishing, along myelinated axons, well conspicuous en passant nodal synapses cannot be explained.

Amphibians↗
PubMed1992

[Disseminated intravascular coagulation induced by endotoxin in rabbits: effect of treatment with t-PA and urokinase].

PURPOSE: To assess the therapeutic efficacy of agents capable of stimulating the fibrinolytic system, such as tissue plasminogen activator (t-PA) and urokinase (UK) on endotoxin-induced disseminated intravascular coagulation (DIC) in the rabbit. MATERIAL AND METHODS: DIC was induced by intravenous administration of endotoxin, 20 micrograms/kg/hr during 6 hr. Four different groups were established: a) control group, receiving only saline solution; b) t-PA group receiving 0.2 mg/kg; c) t-PA group receiving 0.7 mg/kg, and d) UK group, which was given 3,000 IU/kg/hr for 6 hr. Blood samples were drawn before and after 2 hr and 6 hr of endotoxin administration. Platelet count, and fibrinogen, factor XII and antithrombin III concentrations, were assessed in each sample. Mean, standard deviation and percentage of increase or decrease with respect to the basal value, this considered 100%, were used to evaluate the findings. For comparison of values, Student's t and Mann Whitney's U were used; the Fisher test was used for mortality studies. RESULTS: No statistical differences appeared for any of the values in the rabbits under basal conditions. The rabbits in the control group developed DIC. No doses of t-PA modified the changes appearing in blood coagulation. UK reduced the fibrinogen and factor XII consumption induced by endotoxin. The mortality rate in the control group reached 70%. High-dose t-PA decreased such figure to 50%, while low-dose t-PA or UK failed to reduce mortality. CONCLUSIONS: High-dose t-PA has beneficial effects on endotoxin-induced DIC in rabbits. UK failed to achieve such effect at the doses given in this experimental DIC model.

Animals↗
PubMed1992

Age-related quantitative changes in inhibitory axo-somatic synapses on Purkinje cells of rat neocerebellum (Crus I and Crus II).

Morphometric analysis concerning inhibitory axo-somatic synapses on the somata of rat Purkinje cells was carried out. The percentage and the absolute cell surface area occupied with the synaptic junctions as well as their surface-to-somatic volume ratio exhibited significant changes with ageing (from 2 to 24 months). All the parameters revealed the smallest value at 2 months and a peak at 9 months; then, after a decline towards 12 months, they remained fairly constant until 24 months. It is suggested that the observed modifications in the synaptic parameters of the somata would have some connection with compensatory mechanisms for dendritic deafferentation seen with ageing or with the onset and development of the reproductive life of the animals.

Aging↗
PubMed1992

Age-related morphometric changes occurring in the somata of astrocytes of the granular layer of rat neocerebellar cortex (Crus I and Crus II).

A quantitative study concerning the age-related changes occurring in the cell body and somatic organelles of neocerebellar astrocytes is carried out, using rats aged 2 to 24 months. Manual stereological techniques are used to determine the following parameters on electron micrographs: the somatic volume, the volume density and the absolute volume of the protoplasmic structures as well as the mean surface of the rough endoplasmic reticulum cisternae per cell. None of the parameters reveals any clear-cut general temporal pattern. The soma and the cell components show statistically significant differences in the parameters with ageing, excepting the dense bodies (relative and absolute volumes) and the Golgi apparatus (relative volume). There are significant positive linear trends between, on the one hand, the somatic volume and, on the other hand, the absolute volume of either of the following structures: nucleus, glial filaments, ground substance and dense bodies. Some linear correlations between the absolute volumes of organelles are also found. Despite the ability for karyokinesis, it is concluded that astrocytes do undergo changes with ageing.

Aging↗
PubMed1992

[Thrombin-antithrombin complexes and F1+2 prothrombin fragment in coronary revascularization surgery. Relationship with graft occlusion].

PURPOSE: To evaluate the possible role played by activation of the coagulation system in the early occlusion of grafts in patients subjected to aortocoronary bypass. PATIENTS AND METHODS: This study includes 30 patients subjected to coronary revascularization surgery. The plasma rates of thrombin-anti-thrombin complexes (TAT) and 1+2 prothrombin fragments (F1+2) were measured before and after surgery. The studies were performed by enzyme immunoassay techniques. Selective angiography was performed in every patient on the 10th day after surgery. Descriptive statistics, Student's t test and Mann-Whitney U test were used for comparison of means ans statistical analysis. RESULTS: Occlusive lesion was shown by angiography in 15 of the 30 patients. The TAT and F1+2 levels showed a statistically significant increase (p less than 0.001) along the postoperative period, without any correlation regarding the presence or absence of occlusion. The preoperative concentration of TAT was significantly higher in patients with thrombotic occlusion (p less than 0.05). CONCLUSIONS: 1) Marked activation of the coagulation system is present in patients subjected to coronary revascularization surgery. 2) The pre-operative determination of TAT may be of value for predicting early graft occlusion.

Aged↗