Medullar expression of type-A natriuretic peptide receptor in an animal model of hypertension induced by renal mass ablation.

INTRODUCTION: The biological activity of the natriuretic peptide (NP) system is dependent on the balance between NP tissue levels and the local expression of their receptors. In the kidney, the natriuretic peptide receptor type A (NPR-A) is the principal receptor mediating NP activity and is mainly expressed in the renal medulla. An increase in circulating NP levels is well documented in chronic renal failure (CRF); however, the renal expression of NPR-A has not been evaluated in this condition. METHODS: Wistar-Han rats were submitted to right nephrectomy plus ablation of both poles of the left kidney (3/4nx; n=27) or were sham operated (Sham; n=22) and followed for up to 26 weeks post surgery. Blood pressure measurements were performed weekly. Two, 10 and 26 weeks after surgery, renal sodium and creatinine excretion were evaluated and the kidneys removed for NPR-A mRNA quantification by real-time PCR. The results of mRNA quantification are expressed in arbitrary units (AU) set as the mean value of the Sham group (Sham=1 AU), after normalization for GAPDH (p<0.05). weeks after surgery) and in elevated fractional sodium excretion (+270%, 26 weeks after surgery). Although sodium intake was similar in 3/4nx and Sham rats, blood pressure was higher in 3/4nx rats and increased progressively throughout the study. This was accompanied by a marked decrease in NPR-A mRNA levels in the renal medulla from 3/4nx animals at 2, 10 and 26 weeks post surgery. Conclusion: In 3/4nx rats, the expression of NPR-A in the renal medulla of the remnant kidney is markedly reduced from 2 weeks up to 26 weeks post surgery. It is suggested that this may contribute to the progressive increase in blood pressure, as well as to the renal fibrosis observed in 3/4nx rats.     

CRITERIA ADOPTED BY DENTISTS TO INDICATE THE EXTRACTION OF PERIODONTALLY INVOLVED TEETH

When dealing with patients with periodontal disease of variable severities, dentists must often choose between treating and restoring the involved tooth or indicating its extraction. Different criteria have been adopted in this decision-making process. The purpose of this study was to evaluate the criteria adopted by dentists to indicate the extraction of teeth with periodontitis. Dentists were interviewed at their private practices in three cities of the state of Rio Grande do Sul, Brazil. The evaluated criteria included severity of attachment loss, tooth mobility, furcation involvement, prosthetic planning, periodontal-endodontic lesion, possible systemic involvement due to the presence of periodontitis, referral to a periodontist for evaluation, radiographic bone loss greater than 50%, presence of extensive caries, socio-economic and cultural status of the patient, among others. The most often adopted criteria to indicate the extraction of periodontally affected teeth were the presence of mobility (37.5%), severity of attachment loss (24.3%) and radiographic bone loss greater than 50% (21.2%). The results of the present study demonstrated the difficulties faced by dentists to indicate the extraction of teeth with severe attachment loss, in addition to the establishment of an adequate prognosis. Aspects associated with the past disease were still the most often reported to indicate the extraction of teeth for periodontal reasons.     

Natural history and treatment of anorectal strictures complicating Crohn's disease

Forty-four patients seen between 1975 and 1985 with anorectal strictures complicating Crohn's disease have been reviewed to determine the natural history and outcome of surgical treatment. Proctitis was present in 98 per cent, and 93 per cent of patients had sever perianal disease. The site of strictures was rectal in 22, anal in 15 and anorectal in 11 (4 patients had a stricture at 2 sites). Initial treatment was by rectal excision alone in 6, dilatation in 33, and 5 needed no treatment at all. Single dilatation was effective in 15, 8 required two dilatations and in 10 repeated dilatation was necessary. Proctocolectomy was eventually required in 19 patients, 2 have a loop ileostomy and 1 has an ileostomy with a rectal stump in situ. Only 21 remain asymptomatic while 3 continue to need dilatation. Perineal wound healing was delayed in 9 of 19 patients having a proctocolectomy and in 3 the perineal wound has never healed.     

Hodgkin disease: CT of the thymus

The computed tomography (CT) scans in two groups of patients with Hodgkin disease were reviewed to determine the frequency of thymic enlargement. In 50 CT scans from 50 patients with evidence of thoracic disease on CT scans who were examined for primary staging, the thymus was enlarged in 15 of 50 (30%). Fifty CT scans were obtained from 44 patients at the time of 50 separate episodes of known or suspected relapse. Relapse occurred in the mediastinum in 12 episodes, lung parenchyma in five, and both sites in one. Thymic enlargement thought to be due to involvement by disease was present in seven of 18 (38%). Mediastinal disease was associated with thymic enlargement in all but one patient in whom a thymic cyst developed after radiation therapy. Differentiation of thymic enlargement from enlarged superior mediastinal lymph nodes was easily made in all but two patients. Thymic enlargement in the absence of lymph node enlargement may indicate a different disease, since isolated Hodgkin disease of the thymus is uncommon. Primary thymic tumor should be considered initially, whereas after treatment, rebound hyperplasia of the thymus may be the cause of enlargement.     

Solitary bronchioloalveolar carcinoma: CT criteria

The computed tomographic (CT) scans of 30 patients with solitary bronchioloalveolar carcinoma were reviewed. Common features at CT included the peripheral or subpleural location of a pulmonary mass (25 cases), pseudocavitation (18 cases), heterogeneous attenuation (17 cases), irregular margins forming a star pattern (22 cases), and pleural tags (21 cases). Using these CT criteria, four independent observers attempted to identify cases of bronchioloalveolar carcinoma from a larger sample of lung cancers and benign lesions by categorizing a series of test cases into four probability categories. Although the bronchioloalveolar carcinomas were correctly ranked in the two highest probability categories 75% of the time (in 45 of 60 cases), there was considerable overlap with other lung lesions, particularly with adenocarcinoma and large cell undifferentiated carcinoma. However, even though the typical features of bronchioloalveolar carcinoma are not invariable or highly specific, they are characteristic enough to suggest the diagnosis.     

Determination of the cut-off value of serum alanine aminotransferase in patients undergoing hemodialysis, to identify biochemical activity in patients with hepatitis C viremia.

BACKGROUND: Elevated liver enzymes are infrequent in patients with hepatitis C virus (HCV) infection undergoing chronic hemodialysis (HD), suggesting that the alanine aminotransferase (ALT) is a poor predictor of hepatocellular damage in this population. OBJECTIVE: To establish a more appropriate cut-off value of ALT to identify biochemical activity due to HCV infection in HD patients. STUDY DESIGN: A total of 217 patients, with an average age of 51.2 years, were evaluated between January and October 2002; 130 were males (60%). Serum ALT was measured by a kinetic method in five consecutive monthly blood samples, from which an average was obtained and divided by the upper limit of normal (ULN). HCV antibodies were determined using an enzyme immunoassay, the serum HCV-RNA by nested-PCR and HCV genotype by hybridization of the amplified sequence from the 5'-non-coding region. The cut-off value of ALT was obtained from a ROC curve. RESULTS: Within the 217 patients, 18 (8.3%) were anti-HCV-positive, 17 (7.8%) of whom were also HCV-RNA-positive. Genotype distribution was: 1a=47%; 1b=18%; 3a=35%. Mean ALT/ULN (0.77+/-0.57) of the 18 anti-HCV-positive cases was higher (p<0.001) than the negative group (0.38+/-0.23). The mean ALT/ULN (0.81+/-0.57) of the 17 HCV-RNA-positive cases was also higher (p<0.0001) than the negative cases (0.37+/-0.23). The cut-off value of ALT to distinguish the anti-HCV-positive from negative patients was 0.50% or 50% of the ULN (sensitivity=67%; specificity=83%). According to the HCV-RNA, the cut-off value of ALT was 0.45% or 45% of the ULN (sensitivity=71%; specificity=80%). CONCLUSION: Reducing the cut-off of ALT by half, enables a better identification of biochemical activity in patients with HCV infection on chronic HD.     

Main alkaloids from the Brazilian dendrobatidae frog Epipedobates flavopictus: pumiliotoxin 251D, histrionicotoxin and decahydroquinolines.

Epipedobates flavopictus, Dendrobatidae, is a small aposematic frog found in Brazilian Cerrado bioma. In the present work, we isolated and characterized chemically the most abundant alkaloids present in the cutaneous extract of E. flavopictus. The specimens were collected in Pirenópolis (Goiás, Brazil), their skins were removed and extracted with methanol, and submitted to purification by HPLC and identification by gas chromatography and mass spectrometry. Pumiliotoxin 251D, histrionicotoxin 285Da and two decahydroquinolines, 219A and 243A, were identified. The pumiliotoxin 251D was tested on isolated frog sciatic nerve and on isolated guinea pig ileum muscle. The pumiliotoxin 251D slightly reduced the action potentials amplitude of frog sciatic nerve. The crude skin extract of E. flavopictus and the pumiliotoxin 251D produced rhythmic contractions and increased the muscular tension on isolated guinea pig ileum.