A De Novo novel mutation of the EDNRB gene in a Taiwanese boy with Hirschsprung disease.

Hirschsprung disease (HSCR) is a congenital disorder characterized by an absence of ganglion cells in the nerve plexuses of the lower digestive tract. Although mutations in eight different genes (EDNRB, EDN3, ECE1, SOX10, RET, GDNF, NTN, SIP1) have been identified in affected individuals, it is now clear that RET and EDNRB are the primary genes implicated in the etiology of HSCR. All eight genes are involved in the early development of the enteric nervous system, and most act through two distinct biochemical pathways mediated by RET and EDNRB. Mutations in RET and EDNRB account for up to 50% and 5% of HSCR cases in the general population, respectively. Interaction between these two signaling pathways could modify RET expression and, therefore, HSCR phenotype. Here, we report the case of a 1-year-old Taiwanese boy who presented with abdominal distension since birth and bilious vomiting after feeding. HSCR (short-segment type) was diagnosed based on X-ray, lower gastrointestinal series and biopsy findings. Mutation analysis revealed a heterozygous T>C missense mutation in exon 1 of the EDNRB gene, that substitutes the highly conserved cysteine-90 residue in the extracellular domain of the G protein-coupled receptor with an arginine residue (C90R). No RET gene mutation was detected in this patient.     

Suppurative corneal ulceration in Bangladesh

Suppurative keratitis is an important preventable cause of blindness, particularly in the developing world. This study analyses 142 cases of suppurative keratitis referred to Chittagong Eye Infirmary, Bangladesh. Some 53.5% of cases were bacterial and 35.9% were fungal. The five most common pathogens were: Pseudomonas sp. 24%, Streptococcus pneumoniae 17%, Aspergillus sp. 13%, Fusarium sp. 7% and Curvularia sp. 6%. Gram stain and culture results were consistent in 62.6% of cases. Previous antibiotic treatment was a significant factor for failure of culture isolation and less so for Gram stain failure. On Gram stain, 55.9% of pseudomonal cases were missed, but only 2% of fungal cases were missed. Over all, Gram stain had a sensitivity of 62% and positive predictive value of 84% for bacterial cases, and 98% and 94% for fungal cases, respectively. Fungal ulcers were typically filamentous, but an antecedent history of trauma was not common. The most frequent injury was due to rice grains, but the inoculum appeared to be introduced during eye washing with contaminated water. Pseudomonal ulcers occurred most frequently in the monsoon season, and Fusarium cases were seen only in the hot, dry season.     

Psychiatric mental health nursing: challenge and change

. We invited Dr Peplau to provide a personal reflection on the recent history of psychiatric nursing and her thoughts on immediate challenges facing the profession. The paper is an individual scholar's commentary on the way that psychiatry has waxed and waned over the years, in relation to nursing. This historical review discovers and reports a challenge to current practice. Dr Peplau describes a professional shift that is pulling nurses toward the subordinate role observed earlier this century. The paper draws attention to how contemporary practice can be positively influenced, e.g., by giving a structure to the allocation and conduct of nurse–patient time.     

A novel 37-Kd adhesive membrane protein from cloned murine bone marrow stromal cells and cloned murine hematopoietic progenitor cells

The adhesion of hematopoietic progenitor cells to bone marrow stromal cells is critical to hematopoiesis and involves multiple effector molecules. Stromal cell molecules that participate in this interaction were sought by analyzing the detergent-soluble membrane proteins of GBI/6 stromal cells that could be adsorbed by intact FDCP-1 progenitor cells. A single-chain protein from GBI/6 cells having an apparent molecular weight of 37 Kd was selectively adsorbed by FDCP-1 cells. This protein, designated p37, could be surface-radiolabeled and thus appeared to be exposed on the cell membrane. An apparently identical 37- Kd protein was expressed by three stromal cell lines, by Swiss 3T3 fibroblastic cells, and by FDCP-1 and FDCP-2 progenitor cells. p37 was selectively adsorbed from membrane lysates by a variety of murine hematopoietic cells, including erythrocytes, but not by human erythrocytes. Binding of p37 to cells was calcium-dependent, and was not affected by inhibitors of the hematopoietic homing receptor or the cell-binding or heparin-binding functions of fibronectin. It is proposed that p37 may be a novel adhesive molecule expressed on the surface of a variety of hematopoietic cells that could participate in both homotypic and heterotypic interactions of stromal and progenitor cells.     

Prion protein is ubiquitinated after developing protease resistance in the brains of scrapie-infected mice

Although the key event in the pathology of prion diseases is thought to be the conversion of cellular prion protein (PrP(C)) to the protease-resistant scrapie species termed PrP(Sc), the factors that contribute to neurodegeneration in scrapie-infected animals are poorly understood. One probable determinant could be when the accumulation of PrP(Sc) in infected brain overwhelms the ubiquitin-proteasome system and triggers the degenerative cascade. In the present study, it was found that in mouse brains infected with the ME7 scrapie strain, the level of ubiquitin protein conjugates increased significantly at approximately 144 days post-infection (pi) when clinical signs first become apparent. This elevation correlated with the detection of protease-resistant PrP(Sc) and a decline in two endopeptidase activities associated with proteasome function. However, ubiquitination of PrP was only detected at the terminal stage, 3 weeks after the development of clinical symptoms (approximately 165 days pi). These results suggest that ubiquitination of PrP is a late event phenomenon and this conjugation occurs after the formation of protease-resistant PrP(Sc). Whether this post-translational modification and the impairment of proteasome function are pivotal events in the pathogenesis of prion diseases remains to be determined.