Non-enzymatic pretreatment of nerve agent (soman) poisoning: a brief state-of-the-art review

The rapid onset of toxic signs following nerve agent intoxication and the apprehension that current therapy (atropine, oxime, diazepam) may not prevent brain damage, requires supportive pretreatment. Since the current pretreatment drug pyridostigmine fails in protecting brain-AChE, more effective pretreatment is necessary.A main focus of present-day pretreatment research is on bioscavengers, another is on centrally active reversible AChE-inhibitors combined with drugs showing anti-cholinergic, anti-glutamatergic, neuroprotective and non-sedating GABA-ergic activity. Strategies aimed at improving efficacy of pharmacological pretreatment will briefly be discussed. Galantamine, given as a pretreatment or stand-alone therapy, emerged as one of the best medical countermeasures against nerve agent poisoning in guinea pigs. Other preclinical studies demonstrated effective pretreatment consisting of physostigmine combined with procyclidine, scopolamine or bupropion (all single injections), against nerve agent poisoning in guinea pigs. A long sign-free pretreatment with physostigmine (Alzet pump), combined with single injection of procyclidine just before soman poisoning, enhanced the efficacy of a post-poisoning therapy consisting of 3 autoinjector equivalents of HI-6, atropine and diazepam, considerably.     

Psychosocial factors in children with idiopathic musculoskeletal pain: a prospective, longitudinal study

Abstract To explore the role of psychosocial factors in the development and persistence of idiopathic musculoskeletal pain (IMP) in children, 23 children with IMP and 52 children with juvenile chronic arthritis (JCA) were compared at first admission to hospital and at 9 y follow-up. Semistructured interviews were performed at both assessments. At first admission, the prevalence of psychiatric diagnoses was high both in patients with IMP and patients with JCA, but patients with IMP more often had pain models, reported more school stress and more often lived with one biological parent. At follow-up, overall psychosocial functioning and level of chronic family difficulties were improved in both groups, but patients with IMP had a higher prevalence of psychiatric diagnoses and more chronic family difficulties and life events than patients with JCA. The persistence of IMP at follow-up was related to pain models, school stress, less parental education and more chronic family difficulties at first admission. Findings support the association between psychosocial factors and childhood IMP.     

Behavioral performance, brain histology, and EEG sequela after immediate combined atropine/diazepam treatment of soman-intoxicated rats.

It is known that rats poisoned with near-lethal doses of pinacolyl methylphosphonofluoridate (soman) develop brain lesions, particularly when convulsions are induced. When rats were intoxicated with a LD50 of soman and treated immediately thereafter with a combination of low doses of atropine and diazepam (LOW AS/DZ treatment), large decrements in performance of an earlier acquired shuttle-box task were found 6 days after intoxication. In contrast, no such decrements were found in soman-intoxicated animals treated similarly with a combination of high doses of these drugs (HIGH AS/DZ treatment). Surprisingly, surviving LOW AS/DZ animals acquired the same task again at a speed that was almost as fast as before intoxication. Similarly treated animals were examined light-microscopically 24 h after intoxication; in LOW-AS/DZ-treated animals, neuropathology was only observed in animals that had exhibited convulsions, whereas in HIGH AS/DZ animals neither convulsions nor brain damage were observed. Power spectra, obtained from electroencephalograms (EEGs) 6 days after intoxication, revealed significant differences between both treatment groups, particularly in the delta-, theta-, and beta-frequencies. After the HIGH AS/DZ treatment, a significant increase in delta activity was found compared to control values, suggestive of neuropathology. It is concluded that, in contrast with the LOW AS/DZ combination, HIGH AS/DZ prevents active avoidance deficits, convulsions, and light-microscopically detectable neuropathology after soman intoxication. However, the results of EEG measurements suggest that some aberrations may still remain even after the HIGH AS/DZ treatment.     

Neuroprotective effects of modafinil in a marmoset Parkinson model: behavioral and neurochemical aspects

The vigilance-enhancing agent modafinil has neuroprotective properties: it prevents striatal ischemic injury, nigrostriatal pathway deterioration after partial transsection and intoxication with 1-methyl-1,2,3,6-tetrahydropyridine. The present study determines the protective effects of modafinil in the marmoset 1-methyl-1,2,3,6-tetrahydropyridine Parkinson model on behavior and on monoamine levels. Twelve marmoset monkeys were treated with a total dose of 6 mg/kg 1-methyl-1,2,3,6-tetrahydropyridine. Simultaneously, six animals received a daily oral dose of modafinil (100 mg/kg) and six animals received vehicle for 27 days. Behavior was observed daily and the locomotor activity, hand-eye coordination, small fast movements, anxiety-related behavior and startle response of the animals were tested twice a week for 3 weeks. Modafinil largely prevented the 1-methyl-1,2,3,6-tetrahydropyridine-induced change in observed behavior, locomotor activity, hand-eye coordination and small fast movements, whereas the vehicle could not prevent the devastating effects of 1-methyl-1,2,3,6-tetrahydropyridine. Dopamine levels in the striatum of the vehicle+1-methyl-1,2,3,6-tetrahydropyridine-treated animals were reduced to 5% of control levels, whereas the dopamine levels of the modafinil+1-methyl-1,2,3,6-tetrahydropyridine-treated animals were reduced to 41% of control levels. The present data suggest that modafinil prevents decrease of movement-related behavior and dopamine levels after 1-methyl-1,2,3,6-tetrahydropyridine intoxication and can be an efficaceous pharmacological intervention in the treatment of Parkinson's disease.     

Comparing outcomes in renal replacement therapy: how should we correct for case mix?

The need to evaluate the effectiveness of clinical practice to justify expensive therapy in the face of financial constraints in all areas of health care delivery makes it necessary to identify groups of patients who are likely to benefit most from treatment. Various risk stratification methods have been used for analyzing survival probabilities for patients receiving renal replacement therapy. Complicated risk stratification methods produce large numbers of risk groups of small sizes, which makes comparison between individual centers difficult. We compared three simple methods of risk stratification, that divided patients into low-, medium-, and high-risk groups, in a cohort of 1,407 patients who commenced renal replacement therapy in five European countries during a 7-year period. Method 1 considered age (>55 years) and diabetes alone; method 2 used a higher age limit (>70 years) and comorbid illnesses, including those other than diabetes; and method 3 used only the number of comorbidities (none, 1, or > or =2) for stratification. Kaplan-Meier survival curves were constructed for comparison between risk groups and Cox's regression model used to assess strength of relationship with mortality. Although patient survival was significantly different between the low-, medium-, and high-risk groups using all three methods, Cox's regression analysis showed that method 2 provided the greatest discrimination between risk groups. In predicting mortality, method 2 (based on comorbidities and age) showed the highest sensitivity and specificity (84% and 80%, respectively) compared with method 1 (80% and 74%) and method 3 (64% and 82%). Validation of this approach in other populations in a prospective study is required before this method, which takes into account the influences of both age and comorbidity for risk stratification, can be used for comparing survival data and for presenting results of renal replacement therapy.     

Oral Treatment with the NADPH Oxidase Antagonist Apocynin Mitigates Clinical and Pathological Features of Parkinsonism in the MPTP marmoset Model

This study evaluates the therapeutic efficacy of the NADPH oxidase inhibitor apocynin, isolated as principal bioactive component from the medicinal plant Picrorhiza kurroa, in a marmoset MPTP model of Parkinson’s disease (PD). The methoxy-substituted catechol apocynin has a similar structure as homovanillic acid (HVA), a metabolite of dopamine (DA). Apocynin acquires its selective inhibitory capacity of the reactive oxygen species generating NADPH oxidase via metabolic activation by myeloperoxidase (MPO). As MPO is upregulated in activated brain microglia cells of PD patients and in MPTP animal models, the conditions for metabolic activation of apocynin and inhibition of microglia NADPH oxidase are in place. Marmoset monkeys received oral apocynin (100 mg/kg; p.o.) (n?=?5) or Gum Arabica (controls; n?=?5) three times daily until the end of the study, starting 1 week before PD induction with MPTP (1 mg/kg?s.c. for 8 days). Parkinsonian symptoms, motor function, home-cage activity and body weight were monitored to assess the disease development and severity. Post-mortem numbers of the tyrosine hydroxylase expressing DA neurons in the substantia nigra were counted. During the MPTP injections, apocynin limited the body weight loss and relieved parkinsonian symptoms compared to controls (Linear regression, P?<?0.05) indicating a reduction of disease progression. During the last test week, apocynin also improved the hand-eye coordination performance compared with vehicle treatment (resp. 39.3?±?4.5 % and 17.7?±?6.7 %; P?=?0.048) and improved the home cage activity with 32 % (P?=?0.029), indicating anti-Parkinson efficacy. Apocynin also increased the number of surviving DA neurons in MPTP-treated marmosets with 8.5 % (P?=?0.059), indicating a tendency towards a neuroprotective efficacy. In conclusion, compensation for the loss of DA and its metabolite HVA by apocynin mitigates the PD progression and limits the parkinsonian signs and motor-function deterioration.