A clinical trial of creatine in ALS

BACKGROUND

Mitochondrial dysfunction occurs early in the course of ALS, and the mitochondria may be an important site for therapeutic intervention. Creatine stabilizes the mitochondrial transition pore, and is important in mitochondrial ATP production. In a transgenic mouse model of ALS, administration of creatine prolongs survival and preserves motor function and motor neurons.

METHODS

The authors conducted a randomized double-blind, placebo controlled trial on 104 patients with ALS from 14 sites to evaluate the efficacy of creatine supplementation in ALS. The primary outcome measure was maximum voluntary isometric contraction of eight upper extremity muscles, with secondary outcomes including grip strength, ALS Functional Rating Scale-Revised, and motor unit number estimates. Patients were treated for 6 months, and evaluated monthly.

RESULTS

Creatine was tolerated well, but no benefit of creatine could be demonstrated in any outcome measure. CI analysis showed that the study, although powered to detect a 50% or greater change in rate of decline of muscle strength, actually made an effect size of greater than 23% unlikely. It was also demonstrated that motor unit number estimation was performed with acceptable reproducibility and tolerability, and may be a useful outcome measure in future clinical trials.

CONCLUSION

Any beneficial effect of creatine at 5 g per day in ALS must be small. Other agents should be considered in future studies of therapeutic agents to address mitochondrial dysfunction in ALS. In addition, motor unit number estimation may be a useful outcome measure for future clinical trials in ALS.

Role of redox-active iron ions in the decomposition of S-nitrosocysteine in subcellular fractions of porcine aorta

We recently reported that degradation of S-nitrosocysteine in homogenates of porcine aorta increased severalfold in the presence of Mg2+ ions [Kostka, P., Xu, B. & Skiles, E.H. (1999) J. Cardiovasc. Pharmacol. 33, 665-670]. The objective of the present study was to examine this in greater detail. The rate of S-nitrosocysteine degradation by aortic homogenates in the presence of Mg2+ ions exhibited differential sensitivity to chelators of iron ions. Terpyridine and diethylenetriamine penta-acetic acid (5-500 microM) caused a concentration-dependent inhibition of S-nitrosocysteine decay, whereas deferoxamine (100 microM) was ineffective. o-Phenanthroline (250 microM), a selective chelator of Fe2+ ions, potentiated the reaction at low initial concentrations of S-nitrosocysteine (< or = 15 microM) and inhibited the reaction at higher concentrations. The inhibitory effects of o-phenanthroline were related to suppression of S-nitrosocysteine decay by cysteine-mediated reduction of Fe3+. In the presence of o-phenanthroline, S-nitrosocysteine decomposition followed saturable kinetics with K0.5 = 3.8 +/- 0.3 microM and h = 1.8 +/- 0.1 (mean +/- SE, n = 4). Comparison of the rates of S-nitrosocysteine decay in different subcellular fractions showed selective association with the cytosolic fraction, as documented by copurification with lactate dehydrogenase activity. At non-limiting concentrations of S-nitrosocysteine, the rate of degradation in the cytosolic fraction was 4.1 +/- 0.3 nmol.min-1.(mg protein)-1 (n = 4). It is concluded that the cytosolic fraction of porcine aorta contains a protein factor, presumably an enzyme, capable of catalyzing heterolytic decomposition of the S-NO bond of S-nitrosocysteine in a process involving redox cycling of iron ions.

Application of the Inverness Blood Grouping System for semiautomated ABO and D testing of patients' samples

We evaluated the performance of the Inverness Blood Grouping System (IBG Systems, Inc., Laytonsville, MD) for the ABO and D red cell grouping of patients' samples. The IBG System is a semiautomated microplate device for blood grouping and antibody detection We tested 2,051 samples using the IBG System and by manual grouping techniques. In no instance did the IBG System give a final ABO interpretation different from the final manual technique. For three samples, the JBG System's ABO interpretation was different from the manual interpretation. An error in interpretation by the technologist performing the manual testing was responsible for the discrepancies. The IBG System identified one sample as D-positive that was grouped as D-negative by manual testing. The patient's sample had been previously grouped manually as a weak D. Au other D results were in agreement. The IBG System provided ABO interpretatinns without technologist's intervention on 1,765 (86.1%) of the samples. In 153 (7.5%) of the samples, a single, equivocal reaction required visual inspection, but no repeat testing was necessary. In 133 (6.5%) of the samples, either repeat testing or reliance on only the manual results was required for final ABO group interpretation. The IBG System is a reliable and efficient alternative to manual techniques for ABO and D grouping of patients' samples.

Development of a small RGD peptide fibrinogen receptor antagonist with potent antiaggregatory activity in vitro

The development of potent antithrombotic agents from the fibrinogen platelet receptor binding sequences Fg-alpha 572-575 -Arg-Gly-Asp-Ser- and Fg-gamma 400-411 -HHLGGAKQAGDV, believed to be a cryptic RGD-type sequence, is described. The tetrapeptide Ac-RGDS-NH2 itself is capable of inhibiting platelet aggregation in vitro at high concentrations, IC50 91.3 +/- 0.1 microM [in vitro antiaggregatory activity employing dog platelet rich plasma (PRP)/ADP], due to low platelet fibrinogen receptor affinity, Ki 2.9 +/- 1.9 microM (purified, reconstituted human platelet GPIIb/IIIa), relative to fibrinogen, Ki 38.0 +/- 6.0 nM. The peptide is also unstable to plasma, suffering total loss of in vitro activity upon incubation in PRP for 3 h (T1/2 90 min). Only modest improvements in potency were achieved with linear analogues of Ac-RGDS-NH2, while dramatic results were achieved with cyclic analogues, culminating in the cyclic disulfide Ac-cyclo-S,S-[Cys-(N alpha-Me)Arg-Gly-Asp-Pen]-NH2 (SK&F 106760) with improved plasma stability (100% activity after 3 h), affinity (Ki 58 +/- 20 nM purified human receptor), and potency (IC50 0.36 +/- 0.4 microM dog PRP/ADP). The affinity of this peptide is 2 orders of magnitude greater than that of Ac-RGDS-NH2. The affinity of the analogue is also comparable to fibrinogen. This peptide constitutes a first potent small peptide entry into the class of novel antithrombotic agents called fibrinogen receptor antagonists.

Evaluating children's reports of sexual abuse: results from a survey of professionals

Two hundred and twelve professionals were surveyed on their assessment and validation procedures in cases of children's sexual abuse allegations. Specific questions garnered information about practices in interviewing children and accused adults, assessment protocols, criteria used to substantiate the allegations, and factors that might distort children's responses.

Weathering Characteristics of Petroleum Hydrocarbons Deposited in Fine Clay Marine Sediments, Searsport, Maine

Further examination of the 1971 spill site in Long Cove, Searsport, Maine, has been carried out during 1976, and has led to the following observations: 1. Petroleum residues isolated from this spill give the appearance of weathering particularly slowly in the cold anoxic sediments of Long Cove. 2. Leaching from contaminated terrestial sediments onto portions of the intertidal zone on the west shore of the Cove while continuing in trace concentrations does not appear to be making a major contribution to the maintenance of a nearly steady state pollution problem found in several areas of the Cove. 3. On the average, the spill area currently appears to contain roughly 20% less material than in 1971. At a number of sites, however, there appears to have been either little or no decline in gross hydrocarbon concentrations, and essentially no weathering of the aliphatic portions of the petroleum residues. 4. One of the principal factors to influence the character of petroleum residues isolated 5 yr postspill appears to have been the weathering of the hydrocarbons during transport to the site of sediment penetration from upland locations. Thus, the current compound distribution was determined early in the spill period. 5. Repopulation of the Cove by M. arenaria, which is proceeding very slowly, correlates directly with the gross concentration variations of petroleum hydrocarbons. Key words: petroleum, gas chromatography, weathering, clay sediments, Maine