How will we know a lapse when we see one? Comment on Leri and Stewart (2002)

The article by F. Leri and J. Stewart (2002) addresses the validity of animal models of relapse in a more sophisticated manner than does much prior research. These researchers have shown that drug self-administration can be influenced by the presence of drug contingent cues as well as by active self-administration versus passive infusion of "lapse" doses. This research also leads to additional questions about the external validity of animal relapse models. Current relapse models may lack validity because of the parameters of drug exposure, because abstinence is imposed on the organism, and because there is no motivational influence that counters resumption of drug self-administration. F. Leri and J. Stewart's (2002) article encourages a more thorough assessment of the motivational context of relapse models.     

Recent progress in the development of subtype selective nicotinic acetylcholine receptor ligands

Nicotinic acetylcholine receptors (nAChRs) are pentameric ligand gated ion channels, which are found at the neuromuscular junction and in the central and peripheral nervous systems. The channels can be assembled from fourteen known subunits. The exact combination and function of all the channels are still not determined but in the CNS certain combinations have been identified which appear to modulate the release of specific neurotransmitters. Non-specific nAChR agonists like nicotine and epibatidine, have been shown to have interesting pharmacology but their clinical value is limited by their undesirable side effects. Selective ligands for different receptor subtypes have been reported and these compounds are probably the best tools for determining the function of the subtypes. The expectation is that some receptor subtype selective nAChR ligands will be clinically useful for the treatment of a broad range of CNS disorders. The development of stable cell lines functionally expressing specific combinations of subunits has greatly improved our understanding of ligand specificity. There have also been advances in the modelling of the ligand binding site, thanks to the discovery of a homologous snail ACh binding protein the X-ray structure of which was determined in 2001. These techniques should lead to rapid advances in the development of truly subtype selective ligands. In this review we describe recent progress in the area and describe the first 1000 fold selective low molecular weight ligands from the AstraZeneca group. We also comment on the first subtype specific channel modulators.     

14'-Hydroxymytoxin B and 16-hydroxyroridin E,two new cytotoxic trichothecenes from Myrothecium roridum

Two new trichothecenes, 14'-hydroxymytoxin B (1) and 16-hydroxyroridin E (3), were isolated from a fermentation extract of Myrothecium roridum. The structures of 1 and 3 were determined by spectral data interpretation. Both compounds showed potent cytotoxic activity against primary soft-tissue sarcoma cells.     

Olanzapine versus divalproex sodium for the treatment of acute mania and maintenance of remission: a 47-week study

OBJECTIVE: Few double-blind trials have compared longer-term efficacy and safety of medications for bipolar disorder. The authors report a 47-week comparison of olanzapine and divalproex. METHOD: This 47-week, randomized, double-blind study compared flexibly dosed olanzapine (5-20 mg/day) to divalproex (500-2500 mg/day) for manic or mixed episodes of bipolar disorder (N=251). The only other psychoactive medication allowed was lorazepam for agitation. The primary efficacy instrument was the Young Mania Rating Scale; a priori protocol-defined threshold scores were > or =20 for inclusion, < or =12 for remission, and > or = 15 for relapse. Analytical techniques included mixed model repeated-measures analysis of variance for change from baseline, Fisher's exact test (two-tailed) for categorical comparisons, and Kaplan-Meier estimates of time to events of interest. RESULTS: Over 47 weeks, mean improvement in Young Mania Rating Scale score was significantly greater for the olanzapine group. Median time to symptomatic mania remission was significantly shorter for olanzapine, 14 days, than for divalproex, 62 days. There were no significant differences between treatments in the rates of symptomatic mania remission over the 47 weeks (56.8% and 45.5%, respectively) and subsequent relapse into mania or depression (42.3% and 56.5%). Treatment-emergent adverse events occurring significantly more frequently during olanzapine treatment were somnolence, dry mouth, increased appetite, weight gain, akathisia, and high alanine aminotransferase levels; those for divalproex were nausea and nervousness. CONCLUSIONS: In this 47-week study of acute bipolar mania, symptomatic remission occurred sooner and overall mania improvement was greater for olanzapine than for divalproex, but rates of bipolar relapse did not differ.     

Treating depression in Alzheimer disease: efficacy and safety of sertraline therapy,and the benefits of depression reduction: the DIADS

CONTEXT: Major depression affects about 25% of the patients who have Alzheimer disease and has serious adverse consequences for patients and caregivers. Results of prior antidepressant treatment studies have produced contradictory findings and have not fully assessed the benefits of depression reduction. OBJECTIVES: To assess the efficacy and safety of sertraline hydrochloride for the treatment of major depression in Alzheimer disease, and to evaluate the effect of depression reduction on activities of daily living, cognition, and nonmood behavioral disturbance. DESIGN: Randomized, placebo-controlled, parallel, 12-week, flexible-dose clinical trial with a 1-week, single-blind placebo phase. The study was conducted between January 1, 1998, and July 19, 2001. SETTING: University outpatient clinic. PARTICIPANTS: Forty-four outpatients who have probable Alzheimer disease and major depressive episodes. INTERVENTION: Sertraline hydrochloride, mean dosage of 95 mg/d, or identical placebo, randomly assigned. MAIN OUTCOME MEASURES: Response rate, Cornell Scale for Depression in Dementia, Hamilton Depression Rating Scale, Mini-Mental State Examination, Psychogeriatric Depression Rating Scale-activities of daily living subscale, and Neuropsychiatric Inventory to quantify patient behavior disturbance and caregiver distress. RESULTS: In the sertraline-treated group 9 patients (38%) were full responders and 11 (46%) were partial responders compared with 3 (20%) and 4 (15%), respectively, in the placebo-treated group (P =.007). The sertraline-treated group had greater improvements in the scores for the Cornell Scale for Depression in Dementia (P =.002) and Hamilton Depression Rating Scale (P =.01), and a statistical trend toward less decline in activities of daily living on the Psychogeriatric Depression Rating Scale-activities of daily living subscale (P =.07). There was no difference between the treatment groups in Mini-Mental State Examination (P =.22) or Neuropsychiatric Inventory (P =.32) ratings over time. When full responders, partial responders, and nonresponders were compared, full responders only, or full and partial responders had significantly better ratings on activities of daily living (P =.04), behavioral disturbance (P =.01), and caregiver distress (P =.006), but not on the Mini-Mental State Examination (P =.76). Safety monitoring indicated few differences in adverse effects between the 2 treatment groups. CONCLUSIONS: Sertraline is superior to placebo for the treatment of major depression in Alzheimer disease. Depression reduction is accompanied by lessened behavior disturbance and improved activities of daily living, but not improved cognition.     

Evaluation of the effects of chronic mild stressors on hedonic and physiological responses: sex and strain compared

The chronic mild stress (CMS) paradigm was developed in order to simulate in animals the symptom of anhedonia, a major feature of depression. Typically, changes in hedonic status are interpreted from a decrease in either intake or preference for a mild sucrose solution. Although the incidence of clinical depression is significantly higher in women than in men, the study of this disorder in most animal models of depression has been based on the responses of male rodents. The purpose of this study was to compare the effects of 6 weeks of CMS administration among male and female rats of two rat strains, Sprague-Dawley (SD) and Long Evans (LE), with respect to physiological (body, adrenal gland, and spleen weight) and biochemical (plasma corticosterone levels) indices of stress as well as evaluations of 1 and 24 h sucrose intake and preference. Estrous cycle was tracked throughout the study. Overall, our results indicate a slower rate of weight gain in animals, greater in males, exposed to the chronic stressor regime. Furthermore, CMS is shown to disrupt estrous cycling, predominantly in the Long Evans strain of rats. The main behavioral finding was a significant reduction in 24 h sucrose intake in female treated groups, which was not accompanied by alterations in preference. Corticosterone levels were elevated in CMS-treated animals relative to the singly housed control groups, but exposure to a subsequent stressor was not influenced by the stress history. Taken together, the effects of chronic stressor exposure are evident, based on physiological and biochemical indices, although none of the measures distinguished any striking gender specific reactions. The usefulness of sucrose intake or preference as behavioral indices of CMS-induced anhedonia in males and females is modest at best.     

Recombinant adeno-associated viral vector (rAAV) delivery of GDNF provides protection against 6-OHDA lesion in the common marmoset monkey (Callithrix jacchus)

Glial cell line-derived neurotrophic factor (GDNF) has shown potential as a treatment for Parkinson's disease. Recombinant adeno-associated viral vectors expressing the GDNF protein (rAAV-GDNF) have been used in rodent models of Parkinson's disease to promote functional regeneration after 6-OHDA lesions of the nigrostriatal system. The goal of the present study was to assess the anatomical and functional efficacy of rAAV-GDNF in the common marmoset monkey (Callithrix jacchus). rAAV-GDNF was injected into the striatum and substantia nigra 4 weeks prior to a unilateral 6-OHDA lesion of the nigrostriatal bundle. Forty percent of the dopamine cells in the lesioned substantia nigra of the rAAV-GDNF-treated monkeys survived, compared with 21% in the untreated monkeys. Fine dopaminergic fibres were observed microscopically in the injected striatum of some rAAV-GDNF-treated monkeys, suggesting that rAAV-GDNF treatment may have prevented, at least in part, the loss of dopaminergic innervation of the striatum. Protection of dopamine cells and striatal fibre innervation was associated with amelioration of the lesion-induced behavioural deficits. rAAV-GDNF-treated monkeys showed partial or complete protection not only in the amphetamine and apomorphine rotation but also in head position and the parkinsonian disability rating scale. Therefore, our study provides evidence for the behavioural and anatomical efficacy of GDNF delivered via an rAAV vector as a possible treatment for Parkinson's disease.     

Marital support,spousal contact and the course of mild hypertension

OBJECTIVE AND METHODS: To define marital support (MS) and its correlates in a sample of mild hypertensives where marital adjustment (by Dyadic Adjustment Scale, DAS) was related to 3-year left ventricular mass, a secondary analysis was performed on 103 men and women who underwent 24-h ambulatory BP (ABP) monitoring, M-mode echocardiography and completed psychosocial questionnaires at baseline and 3 years. RESULTS: MS, defined as the presence of both marital satisfaction and cohesion (upper quartiles of DAS subscales) at baseline, predicted 3-year left ventricular mass (P=.007), which decreased 8% in the MS group and increased 6.26% in the low MS group. The MS group also had lower 24-h diastolic BP over 3 years (P=.016) than the low MS group. Based on the amount of spousal contact during ABP, MS subjects spent much more time together after 3 years than at baseline (P=.008) and compared to the low MS group (P=.027). CONCLUSION: MS, a construct of both the quality and quantity of contact between spouses, was related to improved 3-year outcome in mild hypertension. Prospective clarification of the role of MS in mild hypertension is required.     

What can analysis of calls to NHS direct tell us about the epidemiology of gastrointestinal infections in the community?

OBJECTIVES: Most gastrointestinal (GI) illness within the UK goes undetected by routine surveillance. A national telephone helpline for health advice (NHS Direct) offers a new source of data on GI infection. We aim to describe NHS Direct calls suggestive of GI infection and the outcome of these calls. METHODS: Details of over 150000 telephone calls were collected from NHS Direct over a 6-month period. Calls about 'diarrhoea', 'vomiting' or 'food poisoning' were defined as GI calls and described according to the age of the patient and call outcome. RESULTS: Gastrointestinal calls accounted for 10.3% of total calls ('diarrhoea'=4.9%, 'vomiting'=5.1%). GI calls as a proportion of total calls were significantly high in children under 1 year (23.5%) and aged 1-4 years (21.5%). Call outcomes which resulted in further NHS care being recommended accounted for 72.3% of total calls and 54.5% of GI calls. CONCLUSIONS: A high proportion of NHS Direct calls were about GI symptoms especially for children under 5 years. When compared with all NHS Direct calls, GI calls were less likely to result in further NHS care being recommended. Analysis of NHS Direct calls provides further insight into GI infection in the community.     

Bioequivalence of azathioprine products

All azathioprine oral tablets are considered bioequivalent by the Food and Drug Administration based on traditional testing. However, since these tests were conducted, it has been determined that some patients have a deficiency of the enzyme most responsible for the metabolism of 6-mercaptopurine-thiopurine methyltransferase (TPMT). Azathioprine is rapidly converted to 6-mercaptopurine, its active metabolite. So it is possible that differences in TPMT activity may influence the bioequivalence of azathioprine products among individuals, especially those patients deficient in TPMT enzyme activity. However, this possibility has not been evaluated.