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Biomedical subjects

D F Chamone

Publications and source records attributed to D F Chamone.

32 records · Page 2Linked to original sources
PubMed1989

Effect of intentional hemodilution on platelet survival in secondary pulmonary hypertension.

Platelet regeneration time was assessed in 13 young adults with pulmonary hypertension and polycythemia secondary to congenital heart defects who underwent isovolemic hemodilution to improve clinical status and coagulation defects. The estimated platelet half-life in patients with Eisenmenger's complex was significantly shortened in comparison with normal subjects (3.8 +/- 1.9 vs 4.8 +/- 1.0 days, p less than 0.05). Hemodilution was carried out with no adverse effects, using low molecular weight dextran solutions. Lowering hematocrit from 61 to 50 percent resulted in a significant increase in platelet half-life from 3.8 +/- 1.9 to 5.7 +/- 1.8 days (p less than 0.02), which was followed by a marked rise in platelet count from 149 +/- 31 to 209 +/- 47 x 10(9) platelets/L (p less than 0.003). Arterial oxygen tension did not change significantly. These observations indicate that high hematocrit levels may have accounted for the shortened platelet survival and thrombocytopenia in these patients. Significant hemodilution may lead to a marked improvement in platelet abnormalities in patients with Eisenmenger's complex.

Adolescent↗
PubMed1988

Plasminogen activator expression and steroid hormone receptors in female breast cancer: a multifactorial study.

In order to evaluate the relationship of plasminogen activator (PA) activity to the expression of estrogen (ER) and progesterone (PR) receptors, we assayed primary tumor specimens from 121 cases of female breast cancer. Other clinical and histopathological variables were also investigated with respect to their possible association with PA activity in the samples. Statistical correlations were examined by stratified analysis techniques and by multiple regression methods. PA activity was higher in tumors which were ER+PR+ than in those exhibiting other subsets of joint receptor expression, a finding which was particularly predominant in tumors from post-menopausal women. Of the other variables examined, only disease stage, nodal status and vascular infiltration presented marginal positive statistical associations with PA activity, although this was not confirmed by multivariate analysis. The latter technique showed that the presence of PR was sufficient to explain the variation in PA levels. However, ER emerged as the sole significantly explanatory factor when ER+PR- patients were removed from analysis. Both PR and age (negatively) were independent contributory factors for PA activity in the analysis of post-menopausal women. None of the variables examined emerged as being significantly associated with PA when data from pre-menopausal patients were used. These findings indicate that PA activity in breast tumor samples is statistically associated with the expression of functional estradiol receptors, although to a lesser extent than PR.

Adult↗
PubMed1987

Human plasma kallikrein: effect on the induced platelet aggregation.

Platelet aggregation induced by ADP, collagen and adrenaline is increased by low concentrations of human plasma kallikrein, which does not cause aggregation by itself and inhibits the aggregation induced by arachidonic acid and Thrombofax in platelet rich plasma, and the aggregation induced by thrombin in washed platelets. At higher concentrations however, plasma kallikrein inhibits the aggregation induced by all the agents tested with platelet rich plasma and also causes a decrease in the aggregation induced in whole blood.

Adenosine Diphosphate↗
PubMed1986

Increased levels of eosinophil-derived PAF-acether activity in a patient with idiopathic hypereosinophilic syndrome.

We describe a patient with idiopathic hypereosinophilic syndrome (IHS) having PAF-acether activity corresponding to 4 X 10(-11) M/10(6) eosinophils as determined by standard aggregation curves prepared with purified PAF-acether. These data suggest that the increased PAF-acether content in patients with IHS may play a role in the development of thrombotic phenomena through platelet activation.

Adult↗
PubMedDate not supplied

Risk of exposure to Chagas' disease among seroreactive Brazilian blood donors.

BACKGROUND: Screening of blood donors for Chagas' disease by using currently available serologic tests is complicated by the lack of adequate sensitivity, discordant results between tests, and the absence of a gold standard. STUDY DESIGN AND METHODS: The study was designed to evaluate the serologic tests by using epidemiologic data relating to the risk of exposure to Trypanosoma cruzi in the urban centers of Brazil. The serologic results obtained from screening 411,617 voluntary blood donations in São Paulo during 1993 and 1994 were reviewed, as well as follow-up results on 1,267 donors who initially were repeatably reactive in at least one of three screening tests. Epidemiologic data were obtained from 321 individuals who on follow-up remained reactive in at least one test and who returned for medical counseling. Controls included 119 screen-negative blood donors and 45 blood donors who were repeatably reactive in at least one screening test but were negative on follow-up. RESULTS: Of the individuals who reacted in three screening tests, 94.6 percent remained reactive on follow-up. Of the individuals who were repeatably reactive in only one screening test, 70.8 percent were negative in all three tests on follow-up. Most individuals who reacted in two or three tests on follow-up had epidemiologic evidence of a risk of exposure to Chagas' disease. A significant proportion (29.1%) of those who were reactive in only one test on follow-up had epidemiologic evidence of exposure to the Chagas' disease vector as compared to 14.6 percent of controls (p = 0.007). This suggests that some of these individuals truly were infected. CONCLUSION: No single test for Chagas' disease is sufficiently sensitive to prevent transfusion transmission of the disease in the urban centers of Brazil.

Animals↗
PubMedDate not supplied

[Renal insufficiency due to lymphomatous infiltration of the kidney: report of 3 cases and review of the literature].

Renal failure in patients with lymphoma or leukemia may be brought about by different causes, including ureteral obstruction, hypercalcemia, hyperuricemia, amyloidosis, immunologically mediated nephrosis and paraproteinemic nephropathy. Lymphomatous or leukemic infiltration of the kidneys is a frequent finding at autopsy but is rarely seen as a cause of renal failure. In this report three patients with lymphomatous infiltration of the kidneys causing renal failure are described. Clinical and laboratory criteria for establishment of diagnosis in such cases are suggested. Using these diagnostic criteria, a renal biopsy may not be necessary.

Acute Kidney Injury↗