A pilot study on the motor effects of rimantadine in Parkinson's disease

The purpose of this pilot study was to determine whether rimantadine, the alpha-methyl derivative of amantadine, might have any antiparkinsonian properties. In an open-label trial, 14 patients (12 de novo and 2 on levodopa treatment) with Hoehn and Yahr stage 2 to 3 Parkinson's disease were placed on rimantadine at doses of 100 to 300 mg/d. No patients had dyskinesias or motor fluctuations. Ten of 14 (71%) reported a mean subjective response of 33% (range 10%-60%) to rimantadine. After treatment, there was a 13% improvement in Hoehn and Yahr staging (p = .01) and a 20% improvement in mean motor Unified Parkinsons Disease Rating Scale scores (p = .02). Rigidity was the most consistently improved feature among the responders. Mean effective dose was 256 mg/d (range 200-300 mg/d). Side effects were mild and transient, with nausea being most common (4/14). We conclude that rimantadine has some motor benefits in Parkinson's disease. A double-blind placebo-controlled study is warranted to validate our findings.     

Pharmacology of A-216546: a highly selective antagonist for endothelin ET(A) receptor

Endothelins, 21-amino acid peptides involved in the pathogenesis of various diseases, bind to endothelin ET(A) and ET(B) receptors to initiate their effects. Here, we characterize the pharmacology of A-216546 ([2S-(2,2-dimethylpentyl)-4S-(7-methoxy-1,3-benzodioxol-5-yl )-1-(N,N-di(n-butyl) aminocarbonylmethyl)-pyrrolidine-3R-carboxylic acid), a potent antagonist with > 25,000-fold selectivity for the endothelin ET(A) receptor. A-216546 inhibited [125I]endothelin-1 binding to cloned human endothelin ET(A) and ET(B) receptors competitively with Ki of 0.46 and 13,000 nM, and blocked endothelin-1-induced arachidonic acid release and phosphatidylinositol hydrolysis with IC50 of 0.59 and 3 nM, respectively. In isolated vessels, A-216546 inhibited endothelin ET(A) receptor-mediated endothelin-1-induced vasoconstriction, and endothelin ET(B) receptor-mediated sarafotoxin 6c-induced vasoconstriction with pA2 of 8.29 and 4.57, respectively. A-216546 was orally available in rat, dog and monkey. In vivo, A-216546 dose-dependently blocked endothelin-1-induced pressor response in conscious rats. Maximal inhibition remained constant for at least 8 h after dosing. In conclusion, A-216546 is a potent, highly endothelin ET(A) receptor-selective and orally available antagonist, and will be useful for treating endothelin-1-mediated diseases.     

Mechanism of action of sodium cyanide on rat diaphragm muscle.

The effects of sodium cyanide (NaCN) were investigated on the contractile and electrophysiological properties of rat diaphragm muscles in vitro. Sodium cyanide (0.1-1.0 mM) produced an initial potentiation of directly elicited twitch tensions, followed by a slow progressive depression. The potentiation and depression were both dependent on the NaCN concentration and stimulation frequency. Muscles exposed to NaCN exhibited marked reductions of creatine phosphate concentration, but ATP levels were not significantly lowered. Sodium cyanide had no effect on the resting potential, input resistance or action potential, indicating that the toxicity of the metabolic inhibitor is not mediated by alterations of membrane excitability or passive electrical properties. Sodium cyanide reduced the amplitude of contractures elicited by 70 mM K(2)SO(4), suggesting that the actions of NaCN cannot be explained by a failure of action potentials to propagate across the muscle surface or within t-tubular membranes. Sodium cyanide suppressed the first phase of the caffeine contracture, an observation consistent with an impaired release of, or reduced sensitivity to, sarcoplasmic reticular Ca(2+), but did not alter the amplitude of the second phase, which represents rigor following ATP depletion. These results, in conjunction with those of previous studies, suggest that the depression in muscle tension following exposure to NaCN may result from alterations in Ca(2+) homeostasis, intracellular acidosis or from accumulation of one or more products of phosphocreatine breakdown.     

Evaluation of phosphoramidon and three synthetic phosphonates for inhibition of botulinum neurotoxin B catalytic activity

Three putative metalloprotease inhibitors were synthesized and tested for their ability to inhibit the catalytic activity of botulinum neurotoxin B light chain (BoNT/B LC). The compounds were designed to emulate the naturally occurring metalloprotease inhibitor phosphoramidon, which has been reported to be a weak antagonist of BoNT/B action. All three analogs contained the dipeptide Phe-Glu in place of Leu-Trp of phosphoramidon and possessed a phenyl, ethyl or methyl group in place of the rhamnose sugar of the parent compound. The inhibitors were evaluated in a cell-free assay based on the detection of a fluorescent product following cleavage of a 50-mer synaptobrevin peptide ([Pya(88)] S 39-88) by BoNT/B LC. This peptide corresponds to the hydrophilic core of synaptobrevin-2 and contains a fluorescent analog L-pyrenylalanine (Pya) in place of Tyr(88). Cleavage of [Pya(88)] S 39-88 by BoNT/B LC gives rise to fragments of 38 and 12 amino acid residues. Quantification of BoNT/B-mediated substrate cleavage was achieved by separating the 12-mer fragment (FETSAAKLKRK-Pya) that contains the C-terminal fluorophore and measuring fluorescence at 377 nm. The results indicate that the phenyl-substituted synthetic compound ICD 2821 was slightly more active than phosphoramidon, but analogs with methyl or ethyl substitutions were relatively inactive. These findings suggest that phosphonate monoesters may be useful for providing insights into the structural requirement of BoNT/B protease inhibitors.     

Limb preservation for reimplantation. a review

Although reimplantation of severed limbs and other parts of the body has become prevalent in recent years, the questions of how best to preserve limbs for reimplantation and how to determine if a transected part is viable have not been fully answered. The problem of preservation involves combating direct anoxic damage to tissue as well as combating the changes in the vascular system that lead to the "no reflow phenomenon." Current information concerning kidney preservation as well as experimental and clinical reports on limb preservation are reviewed in this article, and suggestions are made for further investigations.     

National health accounts: lessons from the U.S. experience

The national health accounts (NHA) are the framework within which type of services and sources of funding for health care expenditures are measured. NHA, devised to portray the structure of health care delivery and financing in the United States, provide essential information necessary for the formulation of public health policy and for international comparison. In this article, the authors describe the importance of the NHA nationally and internationally, and provide a blueprint of the definitions, sources, and methods used to create this system of NHA in the United States.     

Patient-based health status assessments in an outpatient psychiatry setting

OBJECTIVE: The reliability, validity, and feasibility of the routine use of a generic health status instrument, the Short-Form-36 Health Survey (SF-36), were examined in a psychiatric outpatient clinic of a general hospital. METHODS: The sample comprised 411 patients referred to an outpatient psychiatry department between April 1994 and March 1995. They filled out the SF-36 along with their admission forms. Scores and reports were generated, and the results were returned to the charts and used at weekly clinical conference discussions. Feasibility was evaluated using subjective and objective data on administration of the instrument, its psychometric properties, and costs. Results from the outpatient psychiatry patients were compared with those from patients scheduled for elective surgery and a healthy normative sample. RESULTS: Routine administration of the SF-36 was successfully achieved with minimal resistance from staff and patients. The SF-36 provided reliable and valid data. As predicted, patients with emotional disorders scored lower, indicating more impairment, on scales measuring mental health than did the elective surgery patients and the normative sample. However, the psychiatric patients' scores on the physical health scale were lower than clinicians expected. Compared with the elective surgery patients, the psychiatric patients were less impaired on only the physical functioning and bodily pain scales; no difference was found between the two groups in role functioning due to physical problems. CONCLUSIONS: Routine use of the SF-36 in a general hospital psychiatric outpatient clinic was feasible, and the results were reliable, valid, and helpful to clinicians. Psychiatric patients' significantly lower scores in physical health and social and role functioning provided additional information about their difficulties.