Missense mutation clustering in the survival motor neuron gene: a role for a conserved tyrosine and glycine rich region of the protein in RNA metabolism?

The Survival Motor Neuron (SMN) gene shows deletions in the majority of patients with Spinal Muscular Atrophy (SMA), a disease of motor neuron degeneration. To date only two missense mutations have been reported in SMN in patients with SMA. The fact that no SMN-homologues have been forthcoming from data-base searching has resulted in a lack of hypotheses concerning the structural and functional consequences of these mutations. Recently SMN has been shown to interact with heterogeneous nuclear ribonucleoproteins (hnRNPs) suggesting a role in mRNA metabolism. We describe a novel missense mutation and the subsequent identification of a triplicated tyrosine-glycine (Y-G) peptide sequence at the C-terminal of SMN which encompasses each of the three predicted amino acid sequence substitutions. We have identified apparent orthologues of SMN in Caenorhabditis elegans and Schizosaccharomyces pombe. These sequences retain the highly conserved Y-G motif and provide additional support for a role of SMN in mRNA metabolism.      

DIAGNOSTIC INVESTIGATION OF PATIENTS WITH CHRONIC POLYNEUROPATHY: EVALUATION OF A CLINICAL GUIDELINE

Objective: (1) To evaluate a clinical guideline for the diagnostic investigation of patients presenting with signs and symptoms (present for longer than 6 weeks) suggesting a chronic polyneuropathy. (2) To investigate the contribution of electrophysiological studies to a focused search for aetiology in these patients. Methods: A chart review was carried out of a consecutive group of outpatients in 1993-7 at a university department of neurology, with signs and symptoms suggesting a polyneuropathy in whom the diagnostic investigation had been carried out according to a recently introduced guideline. Diagnostic tests were performed and final diagnoses were made. Results: Unnecessary investigations were carried out in 108 (51%) of 213 patients and too few tests in 23 (11%) of these patients. In 82 (48%) of the 172 patients who fulfilled the inclusion criteria neurophysiological tests did not contribute to the final diagnosis. Neurophysiological criteria for demyelination were fulfilled in only 13 (8%) of the 172 patients. Conclusion: In patients presenting with signs and symptoms of chronic polyneuropathy the number of tests in the diagnostic investigation can be considerably reduced. In patients with signs and symptoms of polyneuropathy, providing the clinical phenotype is typical, in the presence of diabetes mellitus, renal failure, HIV infection, alcoholism, or use of potentially neurotoxic drugs further investigations are non-contributory. The significance of electrophysiological studies in the investigation of patients with polyneuropathy is rather to separate sensorimotor neuropathies from pure sensory neuropathies than to distinguish between demyelinating and axonal neuropathies.     

Quality of care for maternal and newborn health: the neglected agenda

The quality of care received by mothers and babies in developing countries is often reported as poor. Yet efforts to address this contributory factor to maternal and newborn mortality have received less attention compared with barriers of access to care. The current heightened concern to achieve Millennium Development Goals 4 & 5 has illuminated the neglected quality agenda. Whilst there is no universally-accepted definition of "quality care", it is widely acknowledged to embrace multiple levels – from patient to health system, and multiple dimensions, including safety as well as efficiency. Quality care should thus lie at the core of all strategies for accelerating progress towards MDG4 &5. Interventions to measure and improve quality need themselves to be evidence-based. Two promising approaches are maternal and perinatal death reviews and criterion-based audit. These and other quality improvement tools have a crucial role to play in the implementation of effective maternal and newborn care.     

Rearrangements of the MLL gene in therapy-related acute myeloid leukemia in patients previously treated with agents targeting DNA- topoisomerase II

Chromosome band 11q23 is frequently involved in acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL) de novo, as well as in myelodysplastic syndromes (MDS) and lymphoma. Five percent to 15% of patients treated with chemotherapy for a primary neoplasm develop therapy-related AML (t-AML) that may show rearrangements, usually translocations involving band 11q23 or, less often, 21q22. These leukemias develop after a relatively short latent period and often follow the use of drugs that inhibit the activity of DNA-topoisomerase II (topo II). We previously identified a gene, MLL (myeloid-lymphoid leukemia or mixed-lineage leukemia), at 11q23 that is involved in the de novo leukemias. We have studied 17 patients with t-MDS/t-AML, 12 of whom had cytogenetically detectable 11q23 rearrangements. Ten of the 12 t-AML patients had received topo II inhibitors and 9 of these, all with balanced translocations of 11q23, had MLL rearrangements on Southern blot analysis. None of the patients who had not received topo II inhibitors showed an MLL rearrangement. Of the 5 patients lacking 11q23 rearrangements, some of whom had monoblastic features, none had an MLL rearrangement, although 4 had received topo II inhibitors. Our study indicates that the MLL gene rearrangements are similar both in AML that develops de novo and in t-AML. The association of exposure to topo II- reactive chemotherapy with 11q23 rearrangements involving the MLL gene in t-AML suggests that topo II may play a role in the aberrant recombination events that occur in this region both in AML de novo and in t-AML.     

Characterization of human platelet glycoprotein antigens giving rise to individual immunoprecipitates in crossed-immunoelectrophoresis

Washed human platelets were labeled with 125I by the lactoperoxidase- catalyzed method and solubilized in 1% Triton X-100. The soluble proteins were analyzed by crossed-immunoelectrophoresis in 1% agarose, employing a rabbit antibody raised against whole human platelets. Analysis of autoradiograms developed from dried agarose gels led to the establishment of a normal reference pattern that was consistent for platelets obtained from more than 50 normal individuals. Six platelet membrane glycoprotein antigens contained in four distinguishable precipitates were identified. Each identification was based on direct sodium dodecyl sulfate-polyacrylamide gel electrophoretic analysis of 125I-antigens contained in individually excised precipitates. These platelet antigens include major membrane glycoproteins previously designated la, lb, lla, llb, llla, and lllb. Glycoproteins llb and llla were shown to be contained in a single immunoprecipitate, while glycoproteins la and lla were routinely detected in a single different immunoprecipitate. Analysis of soluble proteins from platelets of five patients with Glanzmann's thrombasthenia demonstrated either a complete absence or a marked reduction of only one radiolabeled precipitate, that containing membrane glycoproteins llb and llla. Platelet samples from two patients with Bernard-Soulier syndrome were devoid of a different precipitate, that containing membrane glycoprotein lb.     

Current Outcomes of Emergency Large Bowel Surgery

Introduction

Emergency large bowel surgery (ELBS) is known to carry an increased risk of morbidity and mortality. Previous studies have reported morbidity and mortality rates up to 14.3%. However, there has not been a recent study to document the outcomes of ELBS following several major changes in surgical training and provision of emergency surgery. The aim of this study was therefore to explore the current outcomes of ELBS.

Methods

A retrospective review was performed of a prospectively maintained database of the clinical records of all patients who had ELBS between 2006 and 2013. Data pertaining to patient demographics, ASA (American Society of Anesthesiologists) grade, diagnosis, surgical procedure performed, grade of operating surgeon and assistant, length of hospital stay, postoperative complications and in-hospital mortality were analysed.

Results

A total of 202 patients underwent ELBS during the study period. The mean patient age was 62 years and the most common cause was colonic carcinoma (n=67, 33%). There were 32 patients (15.8%) who presented with obstruction and 64 (31.7%) had bowel perforation. The overall in-hospital mortality rate was 14.8% (n=30). A consultant surgeon was involved in 187 cases (92.6%) as either first operator, assistant or available in theatre.

Conclusions

ELBS continues to carry a high risk despite several major changes in the provision of emergency surgery. Further developments are needed to improve postoperative outcomes in these patients.