Autosomal recessive spinal muscular atrophy (SMA) is linked to mutations in the survival motor neuron (SMN) gene. The SMN protein has been implicated at several levels of mRNA biogenesis and is expressed ubiquitously. Studies in various model organisms have shown that the loss of function of the SMN gene leads to embryonic lethality. The human contains two genes encoding for SMN protein and in patients one of these is disrupted. It is thought the remaining low levels of protein produced by the second SMN gene do not suffice and result in the observed specific loss of lower motor neurons and muscle wasting. The early lethality in the animal mutants has made it difficult to understand why primarily these tissues are affected. We have isolated a Drosophila smn mutant. The fly alleles contain point mutations in smn similar to those found in SMA patients. We find that zygotic smn mutant animals show abnormal motor behavior and that smn gene activity is required in both neurons and muscle to alleviate this phenotype. Physiological experiments on the fly smn mutants show that excitatory post-synaptic currents are reduced while synaptic motor neuron boutons are disorganized, indicating defects at the neuromuscular junction. Clustering of a neurotransmitter receptor subunit in the muscle at the neuromuscular junction is severely reduced. This new Drosophila model for SMA thus proposes a functional role for SMN at the neuromuscular junction in the generation of neuromuscular defects.

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A database of 327 patients with advanced Renal Cell Carcinoma (RCC) has been analyzed in order to identify potential baseline prognostic factors predicting for survival, following recombinant Interleukin-2 treatment (rIL-2). All patients received a continuous infusion (CIV). Eligibility criteria were uniform across studies, and included patients with an ambulatory performance status (PS), measurable disease, no CNS metastases, and no major organ compromise. Multivariate analyses identified baseline PS (ECOG 0 vs. 1), time from diagnosis to treatment (DTI greater than 24 months vs. less than or equal to 24 months), and the number of metastatic sites (1 vs. greater than or equal to 2, where lung, bone and other sites are considered as separate sites) as important predictors for survival. Patients can be classified into 4 subgroups, which are a function of the number of risk factors present. Median survival for each subgroup is 28, 17, 10 and 5 months, respectively. The model was validated in an independent cohort of 125 patients with RCC treated with subcutaneous (s/c) rIL-2, and predicted for survival accurately. By determining in which risk group category patients may fall, treating physicians may be better equipped to decide on patient management. The model may also be of value in order to stratify patients in randomized clinical trials.

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Cimetidine 1 g daily is often continued for a fixed period beyond the time of healing of duodenal ulcer on the assumption that it might reduce the subsequent relapse rate. To test this, 194 patients whose ulcers had healed after one month of cimetidine 1 g daily were allocated at random to three groups for further treatment with cimetidine 1 g daily for two months (n -63) or five months (n 66) or placebo (n = 65). Thereafter all patients received placebo. Endoscopy was done routinely every three months, or earlier if symptoms recurred. During follow-up in the placebo phase, which lasted for up to 25 months, the estimated total proportions of patients in the three groups with symptomatic recurrences of ulcer were 80%, 90%, and 77%, respectively; the corresponding proportions with silent plus symptomatic relapses were 92%, 90%, and 100%. The relapse rates were also similar in all three groups. Statistical analysis showed a significant variation in relapse rate but the differences were regarded as clinically unimportant.These findings show that full-dose cimetidine continued for several months beyond the time of healing of duodenal ulcer does not decrease the risk of subsequent relapse.