Type A microsatellite instability in pediatric gliomas as an indicator of Turcot syndrome

Microsatellite instability (MSI) is present in hereditary conditions due to mismatch repair (MMR) gene mutations. Following MSI analysis, tumor samples are classified into MSS (stable), MSI-L (low instability), and MSI-H (high instability) based on the fraction of unstable loci. Another MSI-based classification takes into account the size difference between mutant alleles in tumor DNA compared to wild-type alleles; two types of MSI, A and B, are recognized using this approach, type A being characterized by smaller, more subtle allelic shifts compared to type B. Biallelic mutations of MMR genes are associated with pediatric cancers, including glial tumors, in Turcot syndrome type 1 (TS1). However, most TS1-associated gliomas so far analyzed did not display MSI. We investigated the frequency of MSI in a series of 34 pediatric gliomas of different grade using a panel of five mononucleotide quasimonomorphic markers. Subtle qualitative changes were observed for the majority of markers in two glioblastomas (5.9% of the total series and 33.3% of glioblastomas). In both cases, family histories were compatible with TS1, and mutations of the PMS2 and MLH1 genes were identified. In one family, the MSI patterns were compared between the glioblastoma and a colon cancer from an affected relative, showing a clear qualitative difference, with the former displaying type A and the latter type B instability, respectively. These results were confirmed using additional microsatellite markers, indicating that knowledge of the association between TS1-related glial tumors and subtle type A MSI is important for full ascertainment of TS1 patients and appropriate counselling.     

Hepatitis B immunisation in health care workers

Background: Hepatitis B virus (HBV) infection is an important occupational risk in health care workers (HCW). In spite of HBV vaccine availability in Armed Forces, the high prevalence of HBV infection in HCW continues to be a problem. The study was undertaken to study the HBV vaccine-compliance among HCW.     

Prevalence of pityriasis versicolor in a group of Italian pregnant women

BACKGROUND: Although a predisposing role of pregnancy to Malassezia infections is referred, data on the prevalence of pityriasis versicolor (PV) in pregnant women are not available in literature. OBJECTIVE: To investigate the frequency of PV during pregnancy, 60 pregnant women were clinically and microscopically investigated during and after pregnancy. RESULTS: Fifty-two women completed all visits; three women were affected by PV at first or third trimester of pregnancy, and none at 6 months after delivery. Colonization due to Malassezia yeasts was very significantly (P < 0.01) or significantly increased (P < 0.05) at the third trimester and 6 months after delivery, respectively. No variation was observed between the end of pregnancy and the postpartum (P > 0.05). CONCLUSION: Frequency of PV during pregnancy (5.7%) does not seem different from that reported in general population living in temperate climates (2-5%). However, higher degree of colonization by Malassezia resulted at the end of pregnancy and postpartum.     

Pathogenesis of IgA nephropathy

Summary: Although a genetic predisposition to IgA nephropathy can be documented in a minority of patients, the majority of cases are sporadic. The frequent association with mucosal infections suggest the aetiologic involvement of microbial antigens. However, no particular bacterial or viral strain has clearly been implicated. The involvement of mesangial or endothelial autoantigens has been suggested but not proven in a majority of cases. Most patients have a significantly higher memory repertoire of IgA forming B-lymphocytes in their bone marrow associated with high plasma levels of IgA1 while the mucosally stimulated IgA response against recall antigens is augmented, the mucosal and plasma IgA response after mucosal stimulation by neoantigen is significantly reduced or absent. These observations suggest that IgA nephropathy patients have a defect in raising a mucosal IgA response against novel microbial antigens and that they will suffer from recurrent mucosal infections until they have developed a large enough repertoire of memory B-cells to protect their mucosal surfaces. As a consequence of the recurrent stimulation of the IgA immune system, high levels of plasma IgA are found. The mechanism of IgA deposit formation in the mesangium is unknown. The ensuing inflammatory reaction in the glomeruli may vary from mild to severe, but usually the disease has an indolent course. The progression of IgA nephropathy to renal failure is clinically the most important complication. Recent observations on the role of cytokines in the pathogenesis of interstitial infiltration, interstitial fibrosis and tubular atrophy have created the opportunity to study and manipulate the process of renal scarring and the progression to renal failure.     

Establishing the differential diagnosis of neck lesions.

A thorough physical examination of the head and neck should be included as part of the evaluation of every dental patient. Although they most often represent a self-limited inflammation, a benign neoplasm, or a congenital anomaly, neck lesions can also be malignant. Because the pathologic lesions that can arise in the neck are varied and diverse, the diagnostic thought process should be orderly and inclusive so that a reasonable differential diagnosis can be established and prompt, effective treatment can be rendered.     

Effects induced by bothropstoxin, a component from Bothrops jararacussu snake venom, on mouse and chick muscle preparations.

Bothropstoxin, a 13,700 mol. wt myotoxic phospholipase homologue isolated from the venom of Bothrops jararacussu and devoid of PLA2, proteolytic or hemolytic activities, inhibited muscle twitch tension, evoked either directly or indirectly through stimulation of the motor nerve in the mouse phrenic-diaphragm preparations. The compound action potential of the muscle was also abolished with a similar time course. In addition, the toxin (0.7 mM) evoked membrane depolarization which was inhibited in the presence of 10 mM Ca2+. In chick biventer cervicis muscle, the toxin (2 mM) induced a contracture that reached its maximum amplitude in 44.8 +/- 15.6 min (n = 6) and was not blocked by either d-tubocurarine or tetrodotoxin. The time to maximum amplitude was reduced to 5.5 +/- 1.0 min (n = 4) in nominally Ca(2+)-free Krebs solution and was completely abolished in Ca(2+)-free Krebs solution containing 1 mM EGTA.