Cell cycle deregulation in liver lesions of rats with and without genetic predisposition to hepatocarcinogenesis

Preneoplastic and neoplastic hepatocytes undergo c-Myc up-regulation and overgrowth in rats genetically susceptible to hepatocarcinogenesis, but not in resistant rats. Because c-Myc regulates the pRb-E2F pathway, we evaluated cell cycle gene expression in neoplastic nodules and hepatocellular carcinomas (HCCs), induced by initiation/selection (IS) protocols 40 and 70 weeks after diethylnitrosamine treatment, in susceptible Fisher 344 (F344) rats, and resistant Wistar and Brown Norway (BN) rats. No interstrain differences in gene expression occurred in normal liver. Overexpression of c-myc, Cyclins D1, E, and A, and E2F1 genes, at messenger RNA (mRNA) and protein levels, rise in Cyclin D1-CDK4, Cyclin E-CDK2, and E2F1-DP1 complexes, and pRb hyperphosphorylation occurred in nodules and HCCs of F344 rats. Expression of Cdk4, Cdk2, p16(INK4A), and p27(KIP1) did not change. In nodules and/or HCCs of Wistar and BN rats, low or no increases in c-myc, Cyclins D1, E, and A, and E2F1 expression, and Cyclin-CDKs complex formation were associated with p16(INK4A) overexpression and pRb hypophosphorylation. In conclusion, these results suggest deregulation of G1 and S phases in liver lesions of susceptible rats and block of G1-S transition in lesions of resistant strains, which explains their low progression capacity.     

Helicobacter infection in patients with HCV-related chronic hepatitis,cirrhosis, and hepatocellular carcinoma

Chronic hepatitis may progress to cirrhosis and hepatocellular carcinoma (HCC). HCC represents one of the most common human cancers. Incidence rates for this tumor vary widely on a worldwide, suggesting that environmental factors such as infectious microorganisms, carcinogens, or nutrition play a role in its pathogenesis. Several Helicobacter spp. colonize the liver of animals and induce hepatitis. The aim of this study was to determine whether Helicobacter infection was associated with HCV-related liver diseases in humans. Liver tissue samples, including biopsy and surgically excised tissues, were collected from patients positive for hepatitis C viruses (HCV) RNA in the serum. Genomic DNA was extracted from sections of formalin-fixed paraffin-embedded tissues by using the QIAamp Tissue Kit and subjected to polymerase chain reaction (PCR) analysis using two sets of Helicobacter-specific 16S ribosomal RNA primers. To identify positive samples for H. pylori, a set of primers specific for a conserved region in the H. pylori vacA gene were also used. The patients' H. pylori status was determined by ELISA. Forty-one patients (mean age 54.9, range 19–78 years; 24 men) were studied. Thirty patients had chronic viral hepatitis (CH) without (N = 18) or with (N = 12) cirrhosis (CIR), and 11 patients had HCC. Anti-H. pylori IgG was detected in 54%. The expected 422- and 210-bp fragments of Helicobacter 16S rRNA were amplified from 27% of liver samples, including 17% of CH-CIR and 55% of HCC (P = 0.004). The vacA sequence was amplified in 10 of 41(24%) samples (27% of those with HCC).: These data confirm the presence of H. pylori DNA sequences in human liver and suggest an association of Helicobacter spp. with HCV-related chronic liver diseases. Further studies are needed to ascertain whether Helicobacter spp. infection plays a role in the development of HCC.     

Concomitant focal fibrocartilaginous dysplasia of the tibia and eosinophilic granuloma of the jaw in a child

This 2-year-old child presented with concomitant eosinophilic granuloma of the lower jaw and focal fibrocartilaginous dysplasia of the right tibia. Her eosinophilic granuloma was diagnosed on the basis of the clinical picture, imaging studies and the characteristic histologic appearance. Focal fibrocartilaginous dysplasia was revealed incidentally during the eosinophilic granuloma staging process. After chemotherapy, all signs of eosinophilic granuloma subsided, but focal fibrocartilaginous dysplasia remained without signs of clinical or radiographic progression. The importance of differentiating these two conditions is stressed in order to avoid ineffective and inappropriate treatment of focal fibrocartilaginous dysplasia.     

Medio-thoracic esophageal stenosis,produced by pseudotumoral ulcer

A non-specific esophagitis developed in a young male, apparently determined by heavy abuse of alcohol. Shortly after, a stenotic pseudo-tumoral mediothoracic esophageal lesion was diagnosed. Although there was a high index of suspicion regarding the caustic origin of the lesion, cancer could not be excluded using current diagnostic methods. Temporary feeding jejunostomy was followed by uneventful total esophagectomy and gastric pull-up. Pathologic examination of the resected specimen was a surprise, revealing an esophageal ulcer based on massive severe non-specific esophagitis. Retrospectively, the ulcer was judged as primitive or idiopathic. We discuss some etiopathogenic aspects of common secondary esophageal ulcers (related or not to reflux disease), in contrast with idiopathic esophageal ulcers.     

Molecular diversity of disintegrin-like domains within metalloproteinase precursors of Bothrops jararaca.

Disintegrins are small peptides isolated from the venom of several snake families which act as integrin-antagonists or agonists, interacting with a variety of biological processes mediated by integrins. In this work we describe five new disintegrin-like domains within metalloproteinase precursor sequences, obtained from a Bothrops jararaca venom gland cDNA library. Among the new disintegrin-like domains, four were contained in PIII metalloproteinase precursors, with three of them presenting ECD-motifs and one presenting a new KCD-motif. Moreover, we found three disintegrin-like domains within PII metalloproteinase precursors. Two of them are similar to the already described disintegrins jarastatin and jararacin. The third molecule is unusual, presenting some typical PIII metalloproteinase characteristics but lacking the cysteine-rich domain being, thus, classified as a PII metalloproteinase. Only few reports presented molecules with these characteristics. Sequence analysis suggests that these molecules are intermediate steps between the more ancient PIII and the more recent PII metalloproteinases. We also investigated disintegrin N-terminus diversity in B. jararaca crude venom by purifying jarastatin and jararacin and analyzing them by mass spectrometry.     

Homeostatic regulation of sleep in a genetic model of depression in the mouse: effects of muscarinic and 5-HT1A receptor activation.

In depressed patients, sleep undergoes marked alterations, especially sleep onset insomnia, sleep fragmentation, and disturbances of the Rapid Eye Movement (REM) sleep. Abnormalities of rest-activity rhythms and of hypothalamic-pituitary-adrenocortical function have also been described in these patients. In the present study, we examined the presence of such abnormalities in a recently developed line of mice (Helpless mice-H) that exhibit depression-like behaviors in validated tests, compared to the nonhelpless (NH) line derived from the same colony. Experiments were essentially carried out in females for which previous studies showed marked differences between H and NH lines. Compared to NH mice, the H line exhibited (i) lower basal locomotor activity, (ii) sleep fragmentation, shift towards lighter sleep stages, and facilitation of REM sleep reflected by increased amounts and decreased latency, (iii) larger response to the REM sleep promoting effect of muscarinic receptor stimulation (by arecoline). In contrast, H and NH mice were equally responsive to the REM sleep inhibitory effect of 5-HT1A receptor stimulation (by 8-OH-DPAT). In addition, a deficiency in delta power enhancement after sleep deprivation was observed in the H group, and acute immobilization stress in this group failed to elicit a REM sleep rebound and was associated with a long-lasting raise in serum corticosterone levels. These results further validate H mice as a depression model and suggest they might be of particular interest for investigating the neurobiological mechanisms and possibly genetic substrates underlying sleep alterations associated with depression.     

Purification and biological effects of C-type lectin isolated from Bothrops insularis venom

Bothrops insularis is a snake from Queimada Grande Island, which is an island located about 20 miles away from the southeastern coast of Brazil. Compared to other Brazilian species of Bothrops, the toxinology of B. insularis is still poorly understood. Its C-type lectin is involved in several biological processes including anticoagulant and platelet-modulating activities. We purified the C-type lectin (BiLec) from Bothrops insularis venom and investigated its effect in the isolated kidney. BiLec was purified after two chromatographic steps; firstly, the whole venom was submitted to an HPLC molecular exclusion chromatography followed by a second purification through affinity chromatography. B. insularis lectin (BiLec) was studied as to its effect on the renal function of isolated perfused rat kidneys with the use of six Wistar rats. The concentration of 10 μg/mL increased perfusion pressure (PP; control₆₀=108.27±4.9; BiLec₆₀=112.9±5.4 mmHg; *p<0.05) and renal vascular resistance (RVR; control₆₀=5.38±0.51; BiLec₆₀=6.01±0.57 mmHg; *p<0.05). The urinary flow reduced significantly at 90 and 120 min of perfusion (UF; control₁₂₀=0.160±0.020; BiLec₁₂₀=0.082±0.008 mL g⁻¹ min⁻¹; *p<0.05). Glomerular filtration rate (GFR; control₁₂₀=0.697±0.084; BiLec₁₂₀=0.394±0.063 mL g⁻¹ min⁻¹; *p<0.05) diminished only at 120 min. BiLec did not change the percentage of sodium (TNa⁺), potassium (TK⁺) and chloride tubular transport (TCl⁻). The histological alterations probably reflected direct injury on glomerular and tubular renal cells, as demonstrated by the rise in permeability of glomerular endothelial cells, revealed by the presence of a proteinaceous material in the Bowman space. We postulate that the C-type lectin B. insularis promoted its effects probably through interactions with endothelial cells or through the release of other mediators by tubular, mesangial and endothelial cells.