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Biomedical subjects

J M Silva

Publications and source records attributed to J M Silva.

At least 37 records · Page 2Linked to original sources
PubMed2001

Comparative predictive values of urinary cytology, urinary bladder cancer antigen, CYFRA 21-1 and NMP22 for evaluating symptomatic patients at risk for bladder cancer.

PURPOSE: We study the potential diagnostic use of urinary bladder cancer antigen, CYFRA 21-1 and NMP22*; for evaluating symptomatic patients who present with microscopic hematuria and are at risk for bladder cancer. MATERIALS AND METHODS: Urinary tumor markers were determined in 187 samples from 112 patients symptomatic of bladder cancer (group 1), and 75 with benign and other urological conditions (group 2). Immunoassays were used to measure the 3 selected biomarkers. Sensitivity and specificity were established by previously defined cut points. Biomarker results were reported as corrected and uncorrected for urinary creatinine. Urinalysis was performed in all samples. RESULTS: Positive and negative predictive values were 85.5%, 80.5% and 81.1%, and 80.8%, 79.2% and 76.5% for urinary bladder cancer antigen, CYFRA 21-1 and NMP22, with the cutoffs 9.7 microg./l., 5.4 microg./l and 10.0 units per ml., respectively. These predictives values were 85.2% and 72.5%, respectively, for urinary cytology. The combination of biomarkers decreased the positive predictive values to 72.3% to 78.6% and increased negative predictive values to 84.2% to 86.1%. Urinary tract infection, inflammation and malignancy associated with other genitourinary organs were the primary cause for false-positive test results in the 3 assays evaluated. CONCLUSIONS: With a single biomarker, around 80% of the positive results would have correctly identified symptomatic patients for cystoscopy. Of the negative results 75% would have correctly reduced the number of cystoscopies. Sensitivity and negative predictive values could be improved with the combination of biomarkers but with a loss of specificity and positive predictive values. Urinary tract inflammation and other genitourinary malignancies might contribute to the reduction in specificity of these tests.

Adult↗
PubMed2001

[Coronary angioplasty. Initial experience of the Santa Cruz Hospital].

The initial experience with percutaneous transluminal coronary angioplasty (PTCA) at Santa Cruz Hospital is presented. Between May and November 1984, ten patients with single significant (> 75%) coronary artery obstructions, 8 of the left anterior descending (LAD), 1 of the circumflex (Cx) and one of the right coronary artery (RCA), underwent coronary angioplasty using Gruentzig's technique and steerable catheters. Five patients were cases of chronic stable angina and 5 patients were cases of unstable angina, one of them of acute coronary insufficiency previously treated with intracoronary streptokinase. In every case was possible to cross the lesions which were proximal in 9 cases (7 of the LAD, 1 of the Cx and 1 of the RCA) and distal (LAD) in one case. Primary failure to dilate was seen in 2 cases of unstable angina due to pain and reversible ECG changes. In only 1 case there was occlusion at 9 hours after angioplasty which required emergency bypass operation. Although with a short follow-up, six patients are well and free of symptoms and in only 1 case there was recurrence of angina at four and a half months after PTCA. These results which represent the beginning of the learning curve are considered satisfactory and rewarding.

Adult↗
PubMed2001

Detection of epithelial messenger RNA in the plasma of breast cancer patients is associated with poor prognosis tumor characteristics.

PURPOSE: Free plasma RNA has been scarcely studied in patients with cancer. Here we examine the presence of RNA from epithelial tumors in plasma from a series of breast cancer patients and its correlation with tumor characteristics and circulating tumor cells. EXPERIMENTAL DESIGN: beta-actin mRNA was analyzed to check the viability of plasma RNA in samples from 45 patients with breast cancer and 25 controls. Nested primers were used to detect the presence of cytokeratin 19 (CK19) and Mammaglobin in the same samples. Eleven clinicopathological parameters were studied and correlated with molecular parameters. Additionally, we looked for circulating tumor cells in 16 of these patients and in 10 of the controls. RESULTS: All samples showed detectable quantities of beta-actin RNA. In controls, 3 cases (12%) were positive for Mammaglobin, and 5 (20%) were positive for CK19 RNA; of the 45 patients, 27 cases (60%) were positive for Mammaglobin, and 22 (49%) were positive for CK19. These differences were statistically significant (P = 0.001). Tumor size (P = 0.01) and proliferative index (P = 0.02) were associated with the presence of Mammaglobin, CK19, or both RNAs in plasma. Pathological stage (P = 0.06) was close to significance. Although a statistical relationship was not demonstrated, 9 of the 10 patients with circulating tumor cells showed epithelial mRNAs in plasma. CONCLUSIONS: We conclude that epithelial tumor RNA is detectable in plasma from breast cancer patients and that this finding is associated with a probable poor prognosis and circulating tumor cells.

Actins↗
PubMed2000

Synthesis, characterization, and activity of metabolites derived from the cyclooxygenase-2 inhibitor rofecoxib (MK-0966, Vioxx).

Metabolites of the COX-2 inhibitor rofecoxib (MK-0966, Vioxx) were prepared by synthetic or biosynthetic methods. Metabolites include products of oxidation, glucuronidation, reduction and hydrolytic ring opening. Based on an in vitro whole blood assay, none of the known human metabolites of rofecoxib inhibits COX-1 nor contributes significantly to the inhibition of COX-2.

Animals↗
PubMed2000

DNA damage after chemotherapy correlates with tumor response and survival in small cell lung cancer patients.

To explore the induction of chemotherapy (CT) DNA damage and its correlation with tumor response and patient survival, we undertook the present study in 20 small cell lung cancer (SCLC) patients. All patients underwent the same treatment based on CT courses of carboplatin and etoposide. Blood samples were taken before and immediately after CT and every 12 weeks during follow-up. Nuclear DNA damage was determined through the variations in three mitochondrial pseudogene mutations in DNA of peripheral blood mononuclear cells. They were detected by mutation-specific PCR and assessed by a semiquantitative method. The relative level of mutation rose after chemotherapy in all cases. Among the 11 patients (55%) with higher relative levels of mutations, 9 (82%) of them achieved a complete response. In contrast, of the 9 patients (45%) with lower relative levels of mutations, only 2 (18%) achieved a complete response, displaying a statistically significant difference (P=0.02). The overall survival for patients with marked genomic damage was 18 months (range 10-24), and for patients with low degree of DNA damage, it was 12 months (range 5-15) (P=0.002). Genomic damage detected after chemotherapy treatment correlates positively with tumor response and patient survival.

Adult↗
PubMed2000

Promoter hypermethylation and BRCA1 inactivation in sporadic breast and ovarian tumors.

BACKGROUND: Inherited mutations in the BRCA1 gene may be responsible for almost half of inherited breast carcinomas. However, somatic (acquired) mutations in BRCA1 have not been reported, despite frequent loss of heterozygosity (LOH or loss of one copy of the gene) at the BRCA1 locus and loss of BRCA1 protein in tumors. To address whether BRCA1 may be inactivated by pathways other than mutations in sporadic tumors, we analyzed the role of hypermethylation of the gene's promoter region. METHODS: Methylation patterns in the BRCA1 promoter were assessed in breast cancer cell lines, xenografts, and 215 primary breast and ovarian carcinomas by methylation-specific polymerase chain reaction (PCR). BRCA1 RNA expression was determined in cell lines and seven xenografts by reverse transcription-PCR. P values are two-sided. RESULTS: The BRCA1 promoter was found to be unmethylated in all normal tissues and cancer cell lines tested. However, BRCA1 promoter hypermethylation was present in two breast cancer xenografts, both of which had loss of the BRCA1 transcript. BRCA1 promoter hypermethylation was present in 11 (13%) of 84 unselected primary breast carcinomas. BRCA1 methylation was strikingly associated with the medullary (67% methylated; P =.0002 versus ductal) and mucinous (55% methylated; P =.0033 versus ductal) subtypes, which are overrepresented in BRCA1 families. In a second series of 66 ductal breast tumors informative for LOH, nine (20%) of 45 tumors with LOH had BRCA1 hypermethylation, while one (5%) of 21 without LOH was methylated (P =.15). In ovarian neoplasms, BRCA1 methylation was found only in tumors with LOH, four (31%) of 13 versus none of 18 without LOH (P =.02). The BRCA1 promoter was unmethylated in other tumor types. CONCLUSION: Silencing of the BRCA1 gene by promoter hypermethylation occurs in primary breast and ovarian carcinomas, especially in the presence of LOH and in specific histopathologic subgroups. These findings support a role for this tumor suppressor gene in sporadic breast and ovarian tumorigenesis.

Breast Neoplasms↗
PubMed2000

Absence of point mutations at codon 17 of the mdm2 gene (serine 17) in human primary tumors.

Mdm2 is a phosphoprotein that interacts with protein p53, inhibiting its activity. A serine located in position 17 of Mdm2, has been implicated in its phosphorylation process. We hypothesize that point mutations at serine 17 could block its phosphorylation and thereby increase the p53-Mdm2 interaction. This mechanism could increase the p53 degradation and cause a loss of the protective effect of p53 against tumorigenesis. This hypothesis was based on recent studies in vitro, demonstrating that when serine 17 is mutated, the DNA-dependent protein kinase, activated by genomic damage, is unable to phosphorylate it. Thus, we investigated whether structural point mutations at exon 3 of the Mdm2 gene, affecting codon 17, were present in 162 human primary tumors, 70 breast carcinomas, 14 bladder tumors, 18 colon adenocarcinomas and 60 testicular tumors. Direct sequencing of a fragment (204 bp) of exon 3 of the Mdm2 gene that contains the codon 17 showed no mutations at this position, independently of the presence or absence of p53 gene mutations in the same tumors. These results do not support the hypothesis that mutations in the Mdm2 gene at this level are involved in the tumorigenic process of human cancers.

Codon↗
PubMed2000

Urinary tissue polypeptide-specific antigen for the diagnosis of bladder cancer.

OBJECTIVES: To evaluate the diagnostic characteristics of the urinary measurement of cytokeratin tissue polypeptide-specific antigen (TPS) for the detection of bladder cancer. METHODS: Three hundred thirty-five individuals in five groups were studied: group 1, subjects with microhematuria under suspicion for primary bladder cancer; group 2, patients being followed up with scheduled cystoscopic examinations; group 3, patients in follow-up receiving chemotherapy instillations; group 4, patients with other urologic diseases; and group 5, healthy subjects. Urine samples belonging to subjects from groups 1, 2, and 3 were collected immediately before cystoscopy. Additionally, patients from groups 2 and 3 were monitored with urinary TPS for a minimum period between two cystoscopies. TPS was measured by an enzyme immunosorbent assay. RESULTS: Receiver operating characteristic analysis gave a sensitivity of 64% and a specificity of 84% at a threshold value of 279 U/L. The positive and negative predictive value was 66% and 82%, respectively; accuracy was 77%. TPS could discriminate the presence of bladder tumor sooner than the scheduled cystoscopies in 9 of 19 follow-up patients with recurrence. False-positive results during follow-up were found in 112 urine samples, one third of which were associated with urinary tract infections. TPS did not appear to be specific for bladder cancer, with elevated results in 45% of patients from group 4, which might lead to clinical misinterpretation of urinary TPS results. CONCLUSIONS: Urinary TPS might provide additional information for the detection of bladder cancer as an adjunct to cystoscopy. Considering the false-positive rates, different urologic diseases should be ruled out before making clinical decisions on the basis of elevated urinary TPS results.

Administration, Intravesical↗
PubMed2000

Clinicopathological characteristics of breast carcinomas with allelic loss in the p73 region.

p73, a new member of the p53 family, has been mapped to chromosome 1p 36, a region where loss of heterozygosity (LOH) is frequently observed in primary human tumors. Allelic loss studies involving the 1p arm in breast carcinomas offer rates ranging from 13% to 75%, depending on the genetic interval being studied. We investigated LOH in an intragenic microsatellite marker, and those centromerically flanking the p73 gene, at 1p 36, and their correlations with patient age and 10 pathologic parameters in a series of 193 breast carcinomas. The LOH analysis was performed by amplifying DNA by PCR, using the five markers of the 1p 36 region (p73P1, D1S2694, D1S214, D1S2666 and D1S450). LOH was found in at least one of these markers in 27% of tumors. When we established the comparison between tumors with and without LOH and the distribution of the 10 pathologic parameters considered, we observed statistically significant differences in association with higher histologic grade (p = 0.02), more advanced pathological stage (p = 0.02), peritumoral vessel involvement (p = 0.04) and poorly differentiated carcinomas (p = 0.01), as well as in tumors that concomitantly exhibited lymph node metastases, peritumoral vessel involvement and absence of steroid receptors (p = 0.02). These data suggest that LOH in the p73 region could be pathogenically related to breast cancer and possibly to a poor tumor prognosis.

Adult↗
PubMed2000

Primary megaureter detected by prenatal ultrasonography: conservative management and prolonged follow-up.

With the widespread use of obstetric echography the incidence of fetal hydronephrosis has been reported more frequently. Consequently, many uropathies have been detected in asymptomatic neonates. The authors report their experience with prenatally detected primary non-refluxing megaureter. Newborns with fetal hydronephrosis were investigated by ultrasonography and micturating cystourethrogram after the beginning of chemoprophylaxis. If primary megaureter was identified, after 1 month the children underwent 99tm-DMSA, diuretic 99tm-DTPA, and intravenous urography. Eight infants with primary megaureter (bilateral in 3 cases) were identified, for a total of 11 renal units for study. All children were submitted to non-operative management. We performed ultrasonography and diuretic 99tm-DTPA during follow-up, which lasted on average 75 months. The mean cross-sectional diameter of the dilated ureter was 13.6 mm during neonatal period, and reached 8.4 mm at the end of follow-up. The renal function and the diuretic renogram remained stable throughout follow-up. Two neonates presented transitory hypertension. Our results support the notion that conservative management is safe for primary megaureter detected in asymptomatic neonates, with most cases showing spontaneous regression during a prolonged follow-up.

Female↗
PubMed2000

Microsatellite alterations and TP53 mutations in plasma DNA of small-cell lung cancer patients: follow-up study and prognostic significance.

BACKGROUND: Small-cell lung cancer (SCLC), one of the major types of lung cancer, is associated with many different somatic molecular genetic changes. These alterations, observed in tumor DNA, have also been identified in the plasma DNA of patients. We undertook the present study to make a prospective investigation into the correlation between abnormal plasma DNA and patient survival. PATIENTS AND METHODS: Thirty-five patients with SCLC were selected after histological diagnosis. Polymorphic markers (ACTBP2, UT762 and AR) were chosen for their reported high rate of alterations in SCLC and analyzed in tumor tissue, normal blood cells and plasma DNA. Furthermore, we looked for mutations of the TP53 gene in tumor and plasma DNA. RESULTS: In 25 patients (71%) at least one molecular change precisely matching that of the primary tumor was detected in the plasma DNA. No difference in survival was observed between patients with aberrant plasma DNA and patients without plasma DNA alterations. However, patients with microsatellite modifications and TP53 mutations concomitantly, showed a significant difference (P = 0.02) in survival compared with patients bearing only one of these molecular changes. In 15 cases it was possible to find a correlation either between tumor response and disappearance of abnormal plasma DNA, or tumor progression and persistence of plasma DNA alterations. CONCLUSIONS: Free plasma DNA with molecular alterations is present to a high degree in plasma DNA of SCLC patients and may have a role as a prognostic factor.

Adult↗
PubMed2000

Mutational status of K-ras and TP53 genes in primary sarcomas of the heart.

We investigated three patients with cardiac angiosarcomas and two with cardiac rhabdomyosarcomas, all for mutations at exons 5, 6, 7 and 8 of the p53 gene and at exon 1 of K-ras. No point mutations were observed in the p53 gene in any of the five cases; however, at exon 1 of K-ras, three patients (60%) presented the same mutation at the first base of codon 13 (G to A transition). Interestingly, this mutation was detected in both rhabdomyosarcoma and angiosarcoma histologic sarcoma types.

Adult↗
PubMed2000

Effect of follicle-stimulating hormone on steroid secretion and messenger ribonucleic acids encoding cytochromes P450 aromatase and cholesterol side-chain cleavage in bovine granulosa cells in vitro.

We determined 1) whether the previously observed induction of estradiol secretion in bovine granulosa cells cultured in serum-free conditions is associated with an increase in cytochrome P450 aromatase (P450(arom)) mRNA abundance and 2) whether P450(arom) mRNA levels are responsive to FSH in vitro. Granulosa cells from small (2-4-mm) follicles were cultured in serum-free medium. Estradiol secretion increased with time in culture and was correlated with increased P450(arom) mRNA abundance. Progesterone secretion also increased with time in culture, but P450 cholesterol side-chain cleavage (P450(scc)) mRNA abundance did not. FSH stimulated estradiol secretion and P450(arom) mRNA abundance; the effect was quadratic for both estradiol and P450(arom) mRNA. Estradiol secretion and P450(arom) mRNA levels were correlated. FSH stimulated progesterone secretion and P450(scc) mRNA abundance, although the minimum effective dose of FSH was lower for estradiol (0.1 ng/ml) than for progesterone (10 ng/ml) production. Insulin alone stimulated estradiol secretion and P450(arom) mRNA levels but not progesterone or P450(scc) mRNA abundance. We conclude that this cell culture system maintained both estradiol secretion and P450(arom) mRNA abundance responsiveness to FSH and insulin, whereas P450(scc) mRNA abundance and progesterone secretion were responsive to FSH but not insulin.

Animals↗
PubMed2000

Cellular automata model for citrus variegated chlorosis.

A cellular automata model is proposed to analyze the progress of citrus variegated chlorosis epidemics in São Paulo orange plantations. In this model epidemiological and environmental features, such as motility of sharpshooter vectors that perform Lévy flights, level of plant hydric and nutritional stress, and seasonal climatic effects, are included. The observed epidemic data were quantitatively reproduced by the proposed model on varying the parameters controlling vector motility, plant stress, and initial population of diseased plants.

Biological Evolution↗
PubMed2000

Effect of FSH and cell localization on dimeric inhibin-A secretion from bovine granulosa cells in culture.

We tested the hypotheses that the secretion of dimeric inhibin-A from cultured bovine granulosa cells is stimulated by FSH, and that antral cells secrete more inhibin-A than do mural cells. Cells from the antral or mural compartment of follicles were cultured in defined medium in two culture systems, and dimeric inhibin-A was measured by two-site ELISA or by Western immunoblotting. In the first culture system, dimeric inhibin-A secretion declined with time in culture, but was significantly (P<0.05) higher from antral than from mural cells (as was total inhibin-alpha measured by RIA). The secretion of dimeric inhibin-A and inhibin-alpha from antral but not mural cells was responsive to FSH. In the second culture system, dimeric inhibin-A secretion increased with time in culture, and was significantly stimulated by FSH, but FSH responsiveness was dependent on the concentrations of insulin in the culture medium. The major forms of inhibin-A secreted had molecular masses of approximately 58, 62, 103-116 and >116 kDa; the 32 kDa form was barely detectable. These different forms were all stimulated by FSH, but the >116 and 62 kDa forms were most responsive to FSH. We conclude that (i) FSH stimulates dimeric inhibin-A secretion from bovine granulosa cells, (ii) the 62 kDa form of inhibin-A may be more responsive to FSH than the 58 kDa form, and (iii) the spatial differentiation of granulosa cell function within the follicle previously observed for oestradiol secretion was also observed for inhibin-alpha and dimeric inhibin-A secretion.

Animals↗
PubMed2000

[The angioplasty of chronic coronary occlusions with the excimer laser for debulking followed by stent implantation].

UNLABELLED: Coronary angioplasty (PCI) of chronic total occlusions (CTO), even when successful, are associated to less favourable long term results. The recent use of coronary stents has improved the long term outcome of those interventions. PURPOSE: To evaluate the short term results and long term occurrence of major adverse coronary events (MACE): death, MI, urgent revascularization and the need for a new target vessel revascularization (TVR) in patients with CTO who had previously been submitted to a PCI with excimer laser for plaque debulking followed by a provisional stent. POPULATION: From our database, we selected 19 patients with a mean age of 51 +/- 13 years (18 male) submitted to PCI between 1994 and 1998. Of those patients, 10 had had of a previous MI. Hypertension, smoking habits and hypercholesterolemia were present in 9 patients (42%). Two patients had diabetes. The main reason for PCI was stable angina in 16 patients (84%) and unstable in 3 patients (16%). Single-vessel disease was present in 18 patients (94%) and multiple-vessel in 1 patient (6%); left ventricular ejection fraction was preserved in 18 patients (94%). Single vessel PCI was performed in 16 patients (84%) and double vessel in 3 patients. Plaque debulking with excimer laser was performed in all patients, followed by 23 stents (Multilink--8; Gianturco Roubin--5; Palmaz Schatz--4; others--6). The mean clinical follow-up was 19 months. RESULTS: There were no major short-term clinical events (death, MI or urgent revascularization). During follow-up, TVR was only required in 5 patients (26%), all of them in the first 7 months after PCI. CONCLUSIONS: In the highly selected population, PCI for chronic total occlusion, with excimer laser plaque debulking followed by provisional stents, was a safe procedure with a very acceptable rate of new target vessel revascularization in the follow-up period.

Adult↗
PubMed2000

[J-curve between alcohol consumption and carotid atherosclerosis in patients with dyslipidemia].

BACKGROUND: Cerebrovascular disease is the leading cause of death in Portugal and carotid disease is responsible for 20 to 50% of strokes. As dyslipidaemias and alcoholism are frequent problems in our country, we planned to examine the relationship of alcohol consumption and carotid disease in dyslipidaemic patients, a subject that has never been specifically studied, as far as we know. METHODS: We studied 102 dyslipidaemic patients, 38 females and 64 males. We used the following classification for echo-doppler results; grade 0--normal; grade 1--intimal-medial thickening (> or = 1 mm); grade 2--one plaque; grade 3--two or more plaques; grade 4--haemodynamic disturbance. We measured several biochemical and clinical parameters, including declared alcohol consumption. RESULTS: In a stepwise regression we found that age had the highest correlation with carotid atherosclerosis, followed by alcohol consumption. Visually we noticed a J-curve between alcohol consumption and carotid atherosclerosis, that we confirmed with a polynomial regression (r = 0.318, p = 0.0114). Carotid atherosclerosis increased only with levels of alcohol consumption over 60 g/day, in spite of even lower levels of alcohol consumption being associated with lower HDL-C and higher triglycerides compared to abstainers. Apo(a) significantly decreased with levels of alcohol consumption over 60 g/day. CONCLUSIONS: In spite of inducing a more severe dyslipidaemia, a low to moderate alcohol consumption may not be contraindicated in dyslipidaemic patients, with some of the protective effects of alcohol probably counterbalancing the worse lipid profile.

Adolescent↗