Examination of rofecoxib solution decomposition under alkaline and photolytic stress conditions

Rofecoxib is a highly active and selective cyclo-oxygenase II inhibitor. A stability-indicating method for the assay of rofecoxib has been developed using reverse-phase high-performance liquid chromatography (HPLC). Stress testing of rofecoxib was conducted during the method development and validation. HPLC analysis of rofecoxib solutions stressed under alkaline and photolytic conditions revealed the presence of several degradates. Two main degradates were determined to be the cyclization product formed by photo-cyclization and the dicarboxylate formed by ring opening in the presence of base and oxygen. The identities of these degradates were confirmed by comparison of UV spectra and HPLC retention time with the independently synthesized products. The mechanistic pathways for the formation of these degradates are discussed. Further improvement of the HPLC method's ruggedness has been made based on these studies.     

Organizational culture: its impact on employee relations and discipline in health care organizations

Organizations need to examine their cultures at the level of the "shop floor"--in health care, the point where health care workers deal with patients--to determine if the culture is consistent with management policies and will permit an effective program of reward and discipline. This article describes a case where organizational culture was a major imperative in the outcome of an arbitration case. Discussed is a shop-floor situation in manufacturing holding implications for health care, a setting in which management, by countenancing counterproductive aspects of the culture, made it impossible to apply discipline as needed. The conclusion is that health care organizations that neglect the detrimental elements of their culture may find themselves not only at risk of poor employee relations, but also unable to apply discipline effectively.     

A pilot, randomized, open-label trial assessing safety and pharmakokinetic parameters of co-administration of rivastigmine with risperidone in dementia patients with behavioral disturbances

BACKGROUND: The majority of patients with Alzheimer's disease (AD) or vascular dementia display, in addition to cognitive impairment, various degrees of behavioral disturbances. As the use of cholinesterase inhibitors for the treatment of cognitive impairment in dementia becomes widespread, many of these patients will be treated concomitantly with cholinesterase inhibitors and with anti-psychotic drugs to ameliorate behavioral disturbances. Despite the widespread use of this combination in clinical practice, the safety and tolerability of such combination therapy has not been evaluated in controlled clinical trials. This pilot study examined the effects of addition of risperidone 0.5-2 mg/day to patients on rivastigmine 3-12 mg/day, and vice versa. METHODS: 65 patients suffering from AD, 10 from vascular dementia, and 15 from both were randomized to open label rivastigmine and risperidone, alone or in combination, for 20 weeks. Adverse events caused by co-administration were assessed. RESULTS: No clinically relevant adverse interactions were observed. CONCLUSIONS: These preliminary results indicate that rivastigmine and risperidone can be safely co-administered. Confirmation of these results in large clinical trials studies is warranted.     

Toenail selenium concentration and lung cancer in male smokers (Finland)

Background: The objective of this investigation was to evaluate the association between toenail selenium concentration and lung cancer risk in male smokers. Methods: We conducted a nested case–control study within the Alpha–Tocopherol Beta–Carotene Cancer Prevention Study cohort. This substudy included 250 randomly selected incident lung cancer cases and 250 controls matched on age (up to ± 5 years), intervention group assignment, and date or randomization (±15 days). Odds ratios (ORs) and 95% confidence intervals (CIs) were determined using conditional logistic regression methods. Finland began fortification of argricultural fertilizers in the fall of 1984, increasing the dietary intake, plasma, and toenail selenium concentrations for the population. The present analyses were based on the calculated residual of toenail selenium after regressing it on date of randomization. The selenium residual and the interaction of the residual with date of randomization were included in models with smoking status and body mass index as covariates. Results: We observed a suggestion of a protective association for higher selenium status among men who entered the trial early (when the range of selenium values included very low levels). The OR for men with adjusted toenail selenium concentrations at the 75th percentile compared to those with the lowest selenium concentrations ranged between 0.20 (0.09–0.44) for men randomized earliest in the trail and 0.61 (0.27–1.41) for men randomized in the fifth year. Conclusions: These results suggest that low selenium status may be associated with increased risk for lung cancer.     

Long-term effects of rivastigmine in moderately severe Alzheimer's disease: does early initiation of therapy offer sustained benefits?

Goals of the study included evaluating the long-term efficacy of rivastigmine in Alzheimer's disease (AD) patient categories stratified by baseline dementia severity, and post hoc investigation of particular benefits of early initiation of rivastigmine treatment in moderately severe AD. Both rivastigmine-treated groups (originally randomized to 1-4 or 6-12 mg/day) experienced significantly smaller declines in Alzheimer's Disease Assessment Scale-Cognitive subscale (ADAS-Cog) scores from baseline than the projected placebo group after 52 weeks. Patients receiving rivastigmine from Day 1 experienced significantly less decline compared with patients originally receiving placebo and then initiating rivastigmine treatment after a 6-month delay. Furthermore, cognitive benefits were more robust in patients with moderately severe disease compared with previous reports in mild to moderately severe AD. Findings suggest that early treatment with rivastigmine 6-12 mg/day is associated with sustained long-term cognitive benefits in patients with moderately severe AD. The results support the value of early treatment of AD patients, particularly those with moderately severe AD.     

Growth hormone release during acute and chronic aerobic and resistance exercise: recent findings

Exercise is a potent physiological stimulus for growth hormone (GH) secretion, and both aerobic and resistance exercise result in significant, acute increases in GH secretion. Contrary to previous suggestions that exercise-induced GH release requires that a "threshold" intensity be attained, recent research from our laboratory has shown that regardless of age or gender, there is a linear relationship between the magnitude of the acute increase in GH release and exercise intensity. The magnitude of GH release is greater in young women than in young men and is reduced by 4-7-fold in older individuals compared with younger individuals. Following the increase in GH secretion associated with a bout of aerobic exercise, GH release transiently decreases. As a result, 24-hour integrated GH concentrations are not usually elevated by a single bout of exercise. However, repeated bouts of aerobic exercise within a 24-hour period result in increased 24-hour integrated GH concentrations. Because the GH response to acute resistance exercise is dependent on the work-rest interval and the load and frequency of the resistance exercise used, the ability to equate intensity across different resistance exercise protocols is desirable. This has proved to be a difficult task. Problems with maintaining patent intravenous catheters have resulted in a lack of studies investigating alterations in acute and 24-hour GH pulsatile secretion in response to resistance exercise. However, research using varied resistance protocols and sampling techniques has reported acute increases in GH release similar to those observed with aerobic exercise. In young women, chronic aerobic training at an intensity greater than the lactate threshold resulted in a 2-fold increase in 24-hour GH release. The time line of adaptation and the mechanism(s) by which this training effect occurs are still elusive. Unfortunately, there are few studies investigating the effects of chronic resistance training on 24-hour GH release. The decrease in GH secretion observed in individuals who are older or have obesity is associated with many deleterious health effects, although a cause and effect relationship has not been established. While exercise interventions may not restore GH secretion to levels observed in young, healthy individuals, exercise is a robust stimulus of GH secretion. The combination of exercise and administration of oral GH secretagogues may result in greater GH secretion than exercise alone in individuals who are older or have obesity. Whether such interventions would result in favourable clinical outcomes remains to be established.     

Behavioral phenotyping of GFAP-apoE3 and -apoE4 transgenic mice: apoE4 mice show profound working memory impairments in the absence of Alzheimer's-like neuropathology

For the purpose of studying the potential neurobehavioral effects of different human apolipoprotein E (apoE) isoforms produced within the brain, transgenic (TG) mice were generated in which human apoE3 or apoE4 isoforms were under control of an astrocyte-specific, glial fibrillary acidic protein promoter and these TG mice were bred back to apoE knockout (KO) mice. Behavioral phenotypes of apoE3 and apoE4 TG mice were derived by conducting a longitudinal study in which apoE3 and apoE4 TG mice were compared with apoE KO and wild-type (WT) mice (all male) on several behavioral measures. Analysis of locomotor activity, "open-field" behaviors, acoustic startle/prepulse inhibition, and elevated plus maze data suggested that the apoE TG/KO groups were more "emotionally reactive" than WT mice, with apoE4 mice typically being the most reactive. The absence of performance differences among groups on the rotating holeboard and water navigation tasks suggested intact reference memory processing in apoE TG/KO mice. However, apoE4 mice were profoundly impaired on a working memory-based protocol in the radial arm maze (11-14 months). Nonassociative factors (sensorimotor capacities or emotionality differences) did not appear to confound interpretation of the learning/memory results. Western blot analysis revealed no alterations in the level of synaptic, neuronal, or glial markers in neocortex or hippocampus and histologic analysis revealed no evidence of Abeta deposition or neuritic plaques in the apoE KO/TG mice. Our findings suggest that apoE4 expression in the brain may have selective deleterious effects on memory function in the absence of typical Alzheimer's-like neuropathology.     

Response of patients with Alzheimer disease to rivastigmine treatment is predicted by the rate of disease progression

BACKGROUND: Evidence suggests that disease severity predicts the response of patients with Alzheimer disease (AD) to cholinesterase inhibitor treatment, raising the question of whether disease progression also predicts response to this treatment. OBJECTIVE: To evaluate retrospectively whether rate of disease progression during placebo treatment affects response to subsequent rivastigmine tartrate therapy for patients with mild to moderately severe AD. DESIGN: A 26-week, open-label extension study following a 26-week, double-blind, randomized, placebo-controlled trial. SETTING: Outpatient research centers at 22 sites in the United States. PATIENTS: We studied 187 of 235 patients originally randomized to receive placebo treatment in the double-blind phase of the trial who continued with open-label (rivastigmine) extension therapy. INTERVENTION: Placebo treatment for 26 weeks followed by rivastigmine treatment, 2 to 12 mg/d, for 26 weeks. MAIN OUTCOME MEASURES: Alzheimer's Disease Assessment Scale-cognitive subscale (ADAS-Cog), Progressive Deterioration Scale, Mini-Mental State Examination, and Global Deterioration Scale scores. RESULTS: Rivastigmine administration during open-label extension therapy benefited patients who had progressed slowly and those who had progressed rapidly during initial double-blind placebo treatment. Slowly progressive patients responded with a mean 1.03-point improvement in the week 26 (ie, start of open-label rivastigmine treatment) ADAS-Cog score at 12 weeks of rivastigmine treatment (week 38 of treatment; P =.02 vs week 26). However, more rapidly progressive patients had a significantly larger mean 4.97-point improvement from the week 26 ADAS-Cog score at 12 weeks (with respect to week 26 of treatment and slowly progressive patient scores, P<.001 for both). Thus, a more rapid disease progression rate while receiving placebo treatment was predictive of a significantly stronger patient response to rivastigmine therapy. This relation also was observed with the other 3 outcome measures and was still apparent when accounting for disease severity. CONCLUSIONS: Rate of disease progression for patients with mild to moderate AD seems to predict response to rivastigmine treatment. Patients with more rapidly progressive disease might be particularly likely to benefit from rivastigmine therapy.