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Biomedical subjects

C Guerra

Publications and source records attributed to C Guerra.

At least 37 records · Page 2Linked to original sources
PubMed1995

Homologous conditioned medium enhances expression of TRH in hypothalamic neurons in primary culture.

Primary cultures of hypothalamic cells maintained in the presence of serum were either kept with homologous conditioned medium (CM) (i.e. only half of the medium was removed at each medium change) or without (total medium change). In cultures with homologous CM, TRH levels were increased. The effects of CMs from various intervals of the primary culture were tested. The strongest increases of TRH levels were obtained with CM from cultures enriched with hypothalamic glia.

Amino Acid Sequence↗
PubMed1995

Colorectal carcinomas: diagnosis and preoperative staging by hydrocolonic sonography.

BACKGROUND: The aim of this study was to determine the sensitivity, specificity, and predictive value of hydrocolonic sonography (HS) in the detection and preoperative staging of colonic carcinomas. METHODS: One hundred four patients referred to our department for colorectal disease were examined in a prospective study with conventional transabdominal sonography followed by HS and other well-established means for detection of colorectal cancer. In all diagnosed colorectal carcinomas, surgical resection and histologic examination were carried out, and the histologically confirmed tumor stage was then compared with the stage predicted by HS. RESULTS: HS staged and made a correct diagnosis of carcinoma in 39 of 40 patients, with a sensitivity of 97.5% and a specificity of 98%. Positive predictability was 97.5% and negative predictability 98%. In the evaluation of cancer depth invasion, HS staging was correct in all but one case, in which a T3 tumor was incorrectly judged to be T2. In the assessment of the presence or absence of peritumor metastatic lymph nodes, HS had a sensitivity of 50% and a specificity of 100%. CONCLUSIONS: HS allows the diagnosis and preoperative staging of colorectal carcinomas with high sensitivity, specificity, and predictive value. We highly recommend its preoperative use because of its definitive influence on surgical approach.

Adult↗
PubMed1995

Human T-lymphotropic virus type I and type II infections and correlation with risk factors in blood donors from São Paulo, Brazil.

BACKGROUND: Little is known about the prevalence of and risk factors for human T-lymphotropic virus type I and type II (HTLV-I, HTLV-II) infections in Brazil. STUDY DESIGN AND METHODS: Sera from 17,063 healthy Brazilian donors were screened by enzyme-linked immunosorbent assay for antibody to HTLV-I/II between August 1991 and July 1993. Repeatedly reactive samples were confirmed by Western blot, and discrimination between HTLV-I and HTLV-II was made by polymerase chain reaction or synthetic peptide enzyme-linked immunosorbent assay. A univariate analysis was performed on demographic and serologic data. RESULTS: HTLV-I infection was demonstrated in 83 percent of the 30 donors with reactive serologic tests (0.15% of the total tested [17,063]; 95% CI, 0.09-0.20) and HTLV-II infection in 17 percent (0.03% of the total tested [17,063]; 95% CI, 0.01-0.05). HTLV-I-positive donors were more likely than reference groups to be of Asian ethnicity (odds ratio [OR] 15.1; reference group: whites), more than 50 years old (OR 4.2; reference group: 20-29 years old), and positive for antibody to hepatitis C virus (anti-HCV) (OR 21.8) or to hepatitis B core (antigen) (anti-HBc) (OR 5.7). HTLV-II showed a significant association with anti-HCV (OR 75.2) and anti-HBc (OR 21.8). Eleven of the 25 HTLV-I-positive donors were counseled. Family origin in endemic areas of Japan (n = 4), prior blood transfusion (n = 3), or sexual contact with prostitutes (n = 1) were the risk factors reported by 8 donors. In 3 white men, no risk factors could be identified. CONCLUSION: Both HTLV-I and HTLV-II occur among Brazilian blood donors. HTLV-I is associated with Asian ethnicity, greater age, and the presence of anti-HCV and anti-HBc. Three HTLV-I-positive donors had a history of blood transfusion, which emphasizes the need for HTLV-I/II screening in Brazil.

Adult↗
PubMed1994

IGF-I induces the uncoupling protein gene expression in fetal rat brown adipocyte primary cultures: role of C/EBP transcription factors.

Fetal rat brown adipocytes proliferate and reach confluence when cultured in the presence of serum, almost losing their expression of the tissue-specific gene uncoupling protein (UCP). Confluent cells in a serum-free medium induced the expression of UCP in response to 1.4 nM IGF-I at 72 h, in a time-dependent manner. This effect was not produced by 1 nM insulin. However, insulin but not IGF-I induced the expression of the lipogenic marker malic enzyme, suggesting that IGF-I but not insulin is involved in the thermogenic differentiation process of fetal brown adipocytes. Furthermore, the expression of C/EBP transcription factors was present in fetal brown adipocytes prior culture, decreasing during cell proliferation throughout culture. After confluence, insulin induced the expression of C/EBP alpha and delta, whereas the expression of C/EBP beta remained essentially unmodified. IGF-I induced C/EBP alpha but decreased C/EBP delta, this might indicate that both transcription factors play a reciprocal role in the expression of the tissue specific UCP gene.

Adipocytes↗
PubMed1994

Triiodothyronine induces the expression of the uncoupling protein in long term fetal rat brown adipocyte primary cultures: role of nuclear thyroid hormone receptor expression.

Fetal rat brown adipocytes at the beginning of culture showed a minimal T3 nuclear binding capacity and very low expression of the c-erbA genes, with low steady state levels of the mRNA forms beta-type and 5.5- and 2.6-kilobase (kb) alpha-types. The levels of these mRNA species increased after 7 days in culture in the presence of thyroid hormone-depleted serum; however, no significant increase in nuclear T3-binding capacity was observed. The addition of T3 incremented the abundance of the c-erbA beta-mRNA, induced the appearance of the 6.6-kb c-erbA alpha-mRNA and increased the nuclear T3-binding capacity by 30-fold. Parallel analysis of the uncoupling protein (UCP) mRNA, immunoreactive UCP, and functional UCP (detected by its ability to bind GDP) demonstrated that T3 induced the expression of the UCP gene in long term treated fetal brown adipocytes in culture. The presence of noradrenaline, a positive control for UCP expression, increased only the level of expression of the 5.5-kb c-erbA alpha-mRNA, but values for nuclear T3-binding capacity similar to those obtained in T3-treated cells were observed. Simultaneous addition of both hormones gave a pattern of expression of the c-erbA-mRNA forms similar to those obtained with these agents individually, and no further increment in their separate effects was observed on the nuclear T3-binding capacity and UCP expression.

Adipose Tissue, Brown↗
PubMed1992

[Digestive hemorrhage caused by aorto-duodenal fistula. Report of 5 cases].

The aortoduodeonal fistula is a rare condition and has high mortality. We report five retrospective cases of digestive hemorrhage due to an aortoduodenal fistula (4 secondary and 1 primary) between 1986 and 1990. Three of them died. Attention is called to the importance of clinical suspicion and the main diagnostic methods in early diagnosis such as oral endoscopy. We also enhance the importance of emergency surgery for survival.

Aged↗
PubMed1991

Large-volume paracentesis and intravenous saline: effects on the renin-angiotensin system.

Fourteen cirrhotic patients with tense ascites were treated with total paracentesis and intravenous isotonic saline infusion. Standard liver and kidney function tests, plasma renin activity and aldosterone concentration were measured before, at 48 hrs and at 7 days after total paracentesis. The volume of ascites removed was 7.7 +/- 5.6 l (mean +/- S.E.M.). None of the treated patients had clinical complications or significant alterations in liver or kidney function test results. Paracentesis and intravenous isotonic saline infusion were not associated with significant changes in mean plasma renin activity or plasma aldosterone concentration. These results suggest that this therapeutic procedure could be a safe and cost-effective alternative treatment of tense ascites in patients with cirrhosis.

Aged↗
PubMed1989

Assay of free and total tocainide by high performance liquid chromatography (HPLC) with ultraviolet (UV) detection.

A rapid high performance liquid chromatographic (HPLC) method for the determination of tocainide, using N-(2,6-dimethylphenyl)-2-amino-butanimide as an internal standard, was developed. A methylene chloride extraction involving salting out at pH 9.0 was employed. An 85:15 mixture of 0.025M monobasic potassium phosphate at pH 3.0 and acetonitrile was used as the mobile phase. The separation and quantitative analysis of tocainide was performed on a mixed phase column with a 1.0-mL/min flow rate and detection at 210 nm. Separation of tocainide from some of its metabolites required the use of heptane sulfonic acid as an ion-pairing reagent. For the free-drug assay, the specimen was centrifuged through an Amicon Centrifree filter before being processed.

Anti-Arrhythmia Agents↗
PubMed1988

Nonrandom X chromosome inactivation in B cells from carriers of X chromosome-linked severe combined immunodeficiency.

X chromosome-linked severe combined immunodeficiency (XSCID) is characterized by markedly reduced numbers of T cells, the absence of proliferative responses to mitogens, and hypogammaglobulinemia but normal or elevated numbers of B cells. To determine if the failure of the B cells to produce immunoglobulin might be due to expression of the XSCID gene defect in B-lineage cells as well as T cells, we analyzed patterns of X chromosome inactivation in B cells from nine obligate carriers of this disorder. A series of somatic cell hybrids that selectively retained the active X chromosome was produced from Epstein-Barr virus-stimulated B cells from each woman. To distinguish between the two X chromosomes, the hybrids from each woman were analyzed using an X-linked restriction fragment length polymorphism for which the woman in question was heterozygous. In all obligate carriers of XSCID, the B-cell hybrids demonstrated preferential use of a single X chromosome, the nonmutant X, as the active X. To determine if the small number of B-cell hybrids that contained the mutant X were derived from an immature subset of B cells, lymphocytes from three carriers were separated into surface IgM positive and surface IgM negative B cells prior to exposure to Epstein-Barr virus and production of B-cell hybrids. The results demonstrated normal random X chromosome inactivation in B-cell hybrids derived from the less mature surface IgM positive B cells. In contrast, the pattern of X chromosome inactivation in the surface IgM negative B cells, which had undergone further replication and differentiation, was significantly nonrandom in all three experiments [logarithm of odds (lod) score greater than 3.0]. These results suggest that the XSCID gene product has a direct effect on B cells as well as T cells and is required during B-cell maturation.

Alleles↗
PubMed1988

Esophageal strictures: balloon dilation.

One hundred seventy transnasal balloon catheter dilation procedures were performed in 35 patients with esophageal strictures to assess the efficacy and safety of the procedure. On the average, five dilations were required per patient. Depending on the cause of the esophageal stricture, success rates for the technique ranged from 67% to 87%, with success defined as the resolution of dysphagia to both fluids and solids. Three complications, all perforations, were seen; one perforation required surgical repair. No procedure-related deaths were identified in this series. Balloon catheter dilation can be safely applied to esophageal strictures from a variety of causes, with a high degree of clinical success.

Catheterization↗