Biomedical subjects

G Barreto

Publications and source records attributed to G Barreto.

6 recordsLinked to original sources

PubMed2005

Factors associated with poor outcomes in patients with lupus nephritis.

The objective of this study was to identify the factors associated with important clinical outcomes in a case-control study of 213 patients with lupus nephritis. Included were 47% Hispanics, 44% African Americans and 9% Caucasians with a mean age of 28 years. Fifty-four (25%) patients reached the primary composite outcome of doubling serum creatinine, end-stage renal disease or death during a mean follow-up of 37 months. Thirty-four percent African Americans, 20% Hispanics and 10% Caucasians reached the primary composite outcome (P < 0.05). Patients reaching the composite outcome had predominantly proliferative lupus nephritis (WHO classes: 30% III, 32% IV, 18% V and 5% II, P < 0.025) with higher activity index score (7 +/- 6 versus 5 +/- 5, P < 0.05), chronicity index (CI) score (4 +/- 3 versus 2 +/- 2 unit, P < 0.025), higher baseline mean arterial pressure (MAP) (111 +/- 21 versus 102 +/- 14 mmHg, P < 0.025) and serum creatinine (1.9 +/- 1.3 versus 1.3 +/- 1.0 mg/dL, P < 0.025), but lower baseline hematocrit (29 +/- 6 versus 31 + 5%, P < 0.025) and complement C3 (54 +/- 26 versus 65 + 33 mg/dL, P < 0.025) compared to controls. More patients reaching the composite outcome had nephrotic range proteinuria compared to controls (74% versus 56%, P < 0.025). By multivariate analysis, CI (hazard ratio [95% CI] 1.18 [1.07-1.30] per point), MAP (HR 1.02 [1.00-1.03] per mmHg), and baseline serum creatinine (HR 1.26 [1.04-1.54] per mg/dL) were independently associated with the composite outcome. We concluded that hypertension and elevated serum creatinine at the time of the kidney biopsy as well as a high CI are associated with an increased the risk for chronic renal failure or death in patients with lupus nephritis.

Adult↗

PubMed2000

Transcriptional repression by the insulator protein CTCF involves histone deacetylases.

The highly conserved zinc-finger protein, CTCF, is a candidate tumor suppressor protein that binds to highly divergent DNA sequences. CTCF has been connected to multiple functions in chromatin organization and gene regulation including chromatin insulator activity and transcriptional enhancement and silencing. Here we show that CTCF harbors several autonomous repression domains. One of these domains, the zinc-finger cluster, silences transcription in all cell types tested and binds directly to the co-repressor SIN3A. Two distinct regions of SIN3A, the PAH3 domain and the extreme C-terminal region, bind independently to this zinc-finger cluster. Analysis of nuclear extract from HeLa cells revealed that CTCF is also capable of retaining functional histone deacetylase activity. Furthermore, the ability of regions of CTCF to retain deacetylase activity correlates with the ability to bind to SIN3A and to repress gene activity. We suggest that CTCF driven repression is mediated in part by the recruitment of histone deacetylase activity by SIN3A.

3T3 Cells↗

PubMed1999

Parapharyngeal space tumors: considerations in 26 cases.

CONTEXT: Parapharyngeal space tumors comprise less than 0.5% of all head and neck neoplasms. The majority of these tumors are benign, but surgery is usually required to establish the diagnosis and treat the patients. We present 26 patients treated surgically for tumors arising in the parapharyngeal space (PPS) at the State University of Campinas Hospital--UNICAMP. CASES SERIES: Of these, 17 (65.5%) had benign and 9 (34.6%) malignant neoplasms. The surgical and pathological data relevant to these cases are highlighted, observing any local recurrence, surgical complications and the five-year survival. Neurogenic tumors and soft tissue sarcomas were, respectively, the most frequent benign (35.3%) and malignant neoplasms (44.5%). Benign tumors accounted for the majority of the cases and involved minimal surgical morbidity with no recurrence during a median follow-up of five years. Malignant tumors had a high rate of recurrence and mortality. Surgery is the treatment of choice for PPS tumors. A knowledge of the anatomy of this site is essential for the safe performance of surgical procedures. Malignant neoplasms have a poor prognosis. Fine needle aspiration was helpful in diagnosis of all tumors.

Adolescent↗

PubMed1996

Thermal gelation of meat batters as a function of type and level of fat and protein content.

The rheological behaviour of meat batters during heating was analysed as a function of protein level (10-16%), type (pork back or perirenal/peritoneal fat) and amount (10-22%) of fat used. Fat thermal behaviour was studied by differential scanning calorimetry and rheological properties of batters were assessed using non-destructive measurements (thermal scanning rigidity monitor). The higher the protein content, the higher were the rigidity values displayed by the batters, irrespective of fat type, although the magnitude of these values appeared to be dependent on the amount and characteristics of the fat. The lower the fat content, the lower were the rigidity values of the batters. This behaviour pattern was influenced by the amount of protein present. In general, samples containing perirenal/peritoneal fat exhibited lower rigidity values at high temperatures, whereas at less than 35-40 degrees C, the opposite appeared to be the case.

Animals↗

PubMed1996

Mitochondrial D-loop "signatures" produced by low-stringency single specific primer PCR constitute a simple comparative human identity test.

We have developed a technique called "LSSP-PCR" (low-stringency single specific primer PCR) that detects single or multiple mutations in DNA. A purified DNA fragment is submitted to PCR by using a single primer specific for one of the extremities of the fragment, under conditions of very low stringency. The primer hybridizes specifically to its complementary extremity and nonspecifically to multiple sites within the fragment, in a sequence-dependent manner. A complex set of reaction products is thus created that, when separated by electrophoresis, constitutes a unique "gene signature." We here report the application of LSSP-PCR to the detection of sequence variation in the control (D-loop) region of human mtDNA, which is known to differ significantly between unrelated individuals. We prepared human DNA samples from blood and amplified a 1024-bp portion of the mtDNA control region, using primers L15996 and H408. The amplified mtDNA fragments were then reamplified under LSSP-PCR conditions by using L15996 or H408 as drivers to produce complex signatures that always differed between unrelated individuals and yet were highly reproducible. In contrast, all mother-child pairs tested were identical, as expected from the matrilineal inheritance of mtDNA. Thus, the use of LSSP-PCR to produce D-loop signatures constitutes a powerful new technique for mtDNA-based comparative identity testing.

Base Sequence↗

PubMed1994

Sequence-specific "gene signatures" can be obtained by PCR with single specific primers at low stringency.

Low-stringency single specific primer PCR (LSSP-PCR) is an extremely simple PCR-based technique that detects single or multiple mutations in gene-sized DNA fragments. A purified DNA fragment is subjected to PCR using high concentrations of a single specific oligonucleotide primer, large amounts of Taq polymerase, and a very low annealing temperature. Under these conditions the primer hybridizes specifically to its complementary region and nonspecifically to multiple sites within the fragment, in a sequence-dependent manner, producing a heterogeneous set of reaction products resolvable by electrophoresis. The complex banding pattern obtained is significantly altered by even a single-base change and thus constitutes a unique "gene signature." Therefore LSSP-PCR will have almost unlimited application in all fields of genetics and molecular medicine where rapid and sensitive detection of mutations and sequence variations is important. The usefulness of LSSP-PCR is illustrated by applications in the study of mutants of smooth muscle myosin light chain, analysis of a family with X-linked nephrogenic diabetes insipidus, and identity testing using human mitochondrial DNA.

Animals↗