Histopathological changes in the oesophageal mucosa in Egyptian children with corrosive strictures: A single-centre vast experience

BACKGROUND The caustic ingestion continues to be a major problem worldwide especially in developing countries. The long-term complications include stricture and increased life time risk of oesophageal carcinoma. Patients suffered from corrosive induced oesophageal strictures have more than a 1000-fold risk of developing carcinoma of the oesophagus.AIM To determine the possibility of oesophageal mucosal dysplasia after prolonged dilatation in post corrosive stricture.METHODS This observational study was conducted at the Paediatric Endoscopy Unit in Cairo University Children's Hospital. It included children of both sexes older than 2 years of age who had an established diagnosis of post-corrosive oesophageal stricture and repeated endoscopic dilatation sessions for more than 6 mo. All patients were biopsied at the stricture site after 6 mo of endoscopic dilatation. A histopathological examination of an oesophageal mucosal biopsy was performed for the detection of chronic oesophagitis, inflammatory cellular infiltration and dysplasia.RESULTS The mean age of the enrolled children was 5.9 ± 2.6 years; 90% of the patients had ingested an alkaline corrosive substance(potash). The total number of endoscopic dilatation sessions were ranging from 16 to 100 with mean number of sessionswas 37.2 ± 14.9. Histopathological examination of the specimens showed that 85%of patients had evidence of chronic oesophagitis(group A) in the form of basal cell hyperplasia, hyperkeratosis and subepithelial fibrosis. Thirteen percent of the patients had evidence of reactive atypia(group B) in the form of severe neutrophilic intraepithelial inflammatory cellular infiltration, and 2 patients(2%)had mild squamous dysplasia(group C); we rebiopsied these two patients 6 mo after the initial pathological assessment, guided by chromoendoscopy by Lugol's iodine.CONCLUSION The histopathology of oesophageal mucosal biopsies in post-corrosive patients demonstrates evidence of chronic oesophagitis, intraepithelial inflammatory cellular infiltration and dysplasia. Dysplasia is one of the complications of postcorrosive oesophageal stricture.     

Subunit assembly of hemoglobin: an important determinant of hematologic phenotype

Hemoglobin's physiologic properties depend on the orderly assembly of its subunits in erythropoietic cells. The biosynthesis of alpha- and beta-globin polypeptide chains is normally balanced. Heme rapidly binds to the globin subunit, either during translation or shortly thereafter. The formation of the alpha beta-dimer is facilitated by electrostatic attraction of a positively charged alpha-subunit to a negatively charged beta-subunit. The alpha beta-dimer dissociates extremely slowly. The difference between the rate of dissociation of alpha beta- and alpha gamma-dimers with increasing pH explains the well-known alkaline resistance of Hb F. Two dimers combine to form the functioning alpha 2 beta 2-tetramer. This model of hemoglobin assembly explains the different levels of positively charged and negatively charged mutant hemoglobins that are encountered in heterozygotes and the effect of alpha-thalassemia and heme deficiency states in modifying the level of the variant hemoglobin as well as Hb A2. Electrostatic interactions also affect the binding of hemoglobin to the cytoplasmic surface of the red cell membrane and may underlie the formation of target cells. Enhanced binding of positively charged variants such as S and C trigger a normally dormant pathway for potassium and water loss. Thus, the positive charge on beta c is responsible for the two major contributors to the pathogenesis of Hb SC disease: increased proportion of Hb S and increased intracellular hemoglobin concentration. It is likely that electrostatic interactions play an important role in the assembly of a number of other multisubunit macromolecules, including membrane receptors, cytoskeletal proteins, and DNA binding proteins.     

Relationship among serotype G3P5A rotavirus strains isolated from different host species

The relationship among G3P5A rotavirus strains was analysed by restriction endonuclease assay of the VP4, VP6 and VP7 encoding genes, neutralization assay and phylogenetic analysis. The restriction patterns of the capsid encoding genes were species specific allowing the differentiation among the strains of different origin. The VP7 profiles differentiated human from animal strains more efficiently. The phylogenetic analysis of the VP4 gene demonstrated that HCR3A and K9 are closer related to each other than to other P5A strains. The same occurs to strains Ro1845 and Cat 97. The CU-1 virus appears to be an ancestor of the P5A strains by neutralization and phylogenetic analysis. The results placed the RRV strain definitely in a separate VP4 serotype and genotype from that of P5A strains. Restriction endonuclease assay of the capsid encoding genes seems to be a useful tool to identify the host species of rotavirus strains belonging to the same serotype and/or genotype.     

Hypothermia is a frequent sign of severe hypoglycaemia in patients with diabetes

AimHypothermia is a recognized complication of severe hypoglycaemia, but its prevalence and characteristics are poorly studied. For this reason, this study aimed to evaluate hypothermia in severely hypoglycaemic patients.MethodsA retrospective chart review was performed including all patients discharged between 2007 and 2010 from the Emergency Department of the Geneva University Hospital with a diagnosis of severe hypoglycaemia.ResultsHypothermia was identified in 30 (23.4%) out of 128 patients with severe hypoglycaemia. Its incidence was not affected by age, type of diabetes, season or time of day (day/night). Using linear regression, the lowest recorded temperature was associated with the Glasgow Coma Scale (GCS) score (r2 = 13.8%, P < 0.0001) and inversely associated with the leukocyte count (r2 = 13.1%, P = 0.001).ConclusionHypothermia is a frequent sign of severe hypoglycaemia in patients with diabetes. The associations between hypothermia and the GCS score and the leukocyte count suggest that it is a marker of hypoglycaemia severity and/or duration. Hypothermia may represent an important compensatory mechanism in severe hypoglycaemia, reflecting a decrease in energy demand during glucose deprivation.     

Extracranial tumor vascularity: determination by dynamic CT scanning. Part II: The unit approach

Twenty-eight patients had combined conventional drip infusion CT scans. The information about the anatomic location of the lesion, its configuration, its cross-sectional appearance, its vascularity (as determined by dynamic signature curves), and its clinical presentation were considered as a single overall unit. This diagnostic approach allowed a diagnosis to be made on virtually all of these enhancing lesions without resorting to either a digital venous imaging study or angiographic procedure. In 17 of these cases, such an invasive second procedure was performed either to confirm the CT impression as part of this study or as part of a therapeutic embolization procedure.     

The emerging dental workforce: long-term career expectations and influences. A quantitative study of final year dental students' views on their long-term career from one London Dental School

Background  

Research into the motivation and expectations of the emerging workforce and their short-term expectations has already been reported with a view to informing professional and policy decisions. The objective of this component of the research programme was to examine the long-term goals and perceived influences on final year dental students' professional careers.     

Lymphocytotoxic antibodies in rheumatoid arthritis: relation to HLA-DR2 and rheumatoid factors

During a Swiss multicenter study on HLA-antigens in rheumatoid arthritis (RA), the patients sera were tested for cytotoxic, complement fixing antibodies against autologous B- and T-lymphocytes (LCA). LCA were found in about 25% of the patients. Anti-B and cold-reacting LCA were more frequent than were anti-T and LCA reacting at 37 degrees. Most patients with anti-B had anti-T LCA as well. Among patients with LCA, 46.4% had the HLA-DR2 antigen as opposed to 21.2% of the patients without such antibodies (p = 0.0004). There was no difference between the two groups in regard to the other HLA-DR antigens. The patients with LCA had higher titers of rheumatoid factors and of antinuclear antibodies than those without these antibodies. There was no significant difference between the patients with LCA and those without in regard to severity of disease (radiological stage in relation to duration of disease), extra-articular involvement, the amount of circulating immune complexes, and erythrocyte sedimentation rate.     

生命科学仪器中光电倍增管偏置电路分压精度的提高

目的:分析光电倍增管电压偏置电路对光电倍增管性能的影响,并采取相应措施提高光电倍增管电压偏置电路的精度,以改善光电倍增管的性能。方法:在电阻型光电路倍增管偏置电的基础上,增加双极型晶体管或场效应晶体管构成有源光电倍增管偏置电路;并采用可调恒流技术,以解决温度对电路的影响。结果:在阳极电流为50μA,电阻型光电倍增管偏置电路的线性偏离度已达40%,而用双极性晶体管或场效应晶体管的有源偏置电路的线性偏离度分别为≤7%,≤3%,采用可调恒流技术后,电路的线性偏离度≤1%;如果要求阳极电流为100μA时线性偏离度≤1%时,电阻型光电倍增管偏置电路的功耗为11W,而用双极性晶体管或场效应晶体管的有源偏置电路的总功耗分别在0.18～0.95W,0.12～0.75W。结论:采用场效应晶体管的有源偏置电路显著提高了偏置电压的线性度和稳定性,减少了功耗和体积,加入可调恒流技术后,进一步降低偏置电路的线性偏置度,从而改善了光电倍增管的性能。