The association between meal timing and frequency with cardiometabolic profile in patients with bipolar disorder.

OBJECTIVE: The goal of this study was to explore the association of timing of and frequency of meals with markers of cardiometabolic risk in patients with bipolar disorder in out-patient maintenance treatment. METHODS: We used Pittsburgh Sleep Diary and actigraphy measures for individuals with bipolar I disorder. Linear and logistic regression analyses were used to determine whether dinnertime, instability of dinnertime, and/or interval between meals were associated with metabolic syndrome and its components. RESULTS: Later dinnertime was associated with greater waist circumference (ß = 0.25, P = 0.02) after adjusting for age, sex, dinner-to-bed interval, and sleep duration. Longer breakfast-to-lunch intervals were also associated with greater waist circumferences (ß =-.35, P = .002) after adjusting for age, sex, and sleep duration. Neither instability of dinnertime nor number of meals per day was associated with the metabolic syndrome or its components. CONCLUSION: Weight gain is often perceived as inevitable side-effect of medications. While patients often need to be on medication to function, a more careful lifestyle assessment with attention to social rhythms and timing of activities may be critical not only for mood stability, but also to reduce cardiovascular risk.

Sleep duration is associated with dyslipidemia in patients with bipolar disorder in clinical remission.

BACKGROUND: The pathways to increased cardiovascular risk in bipolar disorder include health behaviors, psychosocial stress and long-term medication exposure. However, the evidence that the association between cardiovascular risk factors and bipolar disorder remains significant after controlling for these co-factors suggests that additional important risk factors have yet to be identified. Our hypothesis is that disturbances in the sleep-wake cycle are an important and under-recognized pathway through which affective disorders lead to increased cardiovascular risk. METHODS: In patients with bipolar disorder type 1 in clinical remission, we: 1) explored whether sleep disturbance predicted the endorsement of NCEP ATP-III criteria for dyslipidemia, independent of other lifestyle factors and 2) tested the association between low HDL (NCEP-ATP III) and sleep duration measured with actigraphy over an eight-day period. RESULTS: Median sleep duration is significantly associated with low HDL. The risk of having low HDL increases by 1.23 with every 30 minutes of reduced sleep time. LIMITATIONS: Since sleep patterns in patients with bipolar disorder are variable and irregular, it is possible that other sleep characteristics, not present during the span of our study, or the variability itself may be what drives the increased cardiovascular risk. CONCLUSIONS: Sleep characteristics of patients with bipolar disorder in clinical remission are associated with cardiovascular risk. More specifically, sleep duration was associated with low HDL. Clinicians should pay special attention to sleep hygiene in treating individuals with bipolar disorder, even when they are in clinical remission.

Therapeutic efficacy of aortic administration of N-acetylcysteine as a chemoprotectant against bone marrow toxicity after intracarotid administration of alkylators, with or without glutathione depletion in a rat model.

Modulation of thiol levels may alter both the efficacy and toxicity of chemotherapeutic agents. We investigated cytoenhancement, using L-buthionine-[S,R]-sulfoximine (BSO) to reduce cellular glutathione levels prior to intracarotid alkylator administration. We also evaluated chemoprotection against chemotherapy-induced systemic toxicity when the thiol agents N-acetylcysteine (NAC) and sodium thiosulfate were administered into the descending aorta to limit brain delivery. BSO treatment reduced rat brain and intracerebral tumor glutathione levels by 50-65%, equivalent to the reduction in liver and s.c. tumor. BSO treatment significantly enhanced the toxicity of chemotherapy with carboplatin, melphalan, and etoposide phosphate against granulocytes, total white cells, and platelets. Intracarotid administration of NAC resulted in high delivery to the brain, whereas infusion via the descending aorta minimized brain delivery. When NAC, with or without sodium thiosulfate, was administered via aortic infusion prior to chemotherapy, the magnitude of the bone marrow toxicity nadir was minimized, even with BSO-enhanced myelosuppression. Thus, BSO depleted brain and brain tumor glutathione but thereby increased chemotherapy-induced myelosuppression. Surprisingly, although NAC was found to readily cross the blood-brain barrier when given into the carotid artery, aortic infusion of NAC resulted in minimal exposure to the central nervous system (CNS) vasculature because of rapid clearance. As a result, aortic infusion of NAC to perfuse bone marrow and minimize myelosuppression and toxicity to visceral organs could be performed without interfering with the CNS cytotoxicity of intracarotid alkylators, even after BSO depletion of CNS glutathione.

Capturing the circadian rhythms of free-running blind people with 0.5 mg melatonin.

We have recently shown that six of seven totally blind people (who had free-running circadian rhythms with periods longer than 24 h) could be entrained (synchronized) to a nightly dose of 10 mg melatonin. After treatment discontinuation and re-entrainment to the 10 mg dose, we further found in three of these subjects that the dose could be gradually reduced to 0.5 mg without loss of effect. The question then arose: can a de novo (starting) dose of 0.5 mg initially capture free-running rhythms? Following withdrawal of the stepped-down 0.5 mg dose and consequent release into a free-run, the same three individuals were given 0.5 mg of melatonin de novo. All entrained within a few weeks.

Pretreatment circadian period in free-running blind people may predict the phase angle of entrainment to melatonin.

To date, we have entrained (synchronized) eight totally blind people with free-running circadian rhythms to a nightly dose of 10 mg of melatonin. Each person entrained at a different phase angle of entrainment (PAE), which is the interval in hours between the time of the melatonin dose and the time of the endogenous melatonin onset. When the PAE was plotted against the pretreatment free-running (i.e. slightly different than 24.0 h) circadian period (tau), the fitted regression line revealed a significant correlation, which is consistent with previous findings on light entrainment of rest-activity rhythms in free-running rodents [Pittendrigh and Daan, J. Comp. Physiol., 106 (1976) 291-331].

Injectable chemotherapeutic microspheres and glioma I: enhanced survival following implantation into the cavity wall of debulked tumors.

PURPOSE: Implantation of biodegradable polymers provides a powerful method to deliver high, sustained concentrations of chemotherapeutics to brain tumors. The present studies examined the ability of injectable polymeric microspheres, formulated to release carboplatin or BCNU for 2-3 weeks, to enhance survival in a rodent model of surgically-resected glioma. METHODS: Rat glioma (RG2) cells were implanted into the cortex of rats and allowed to grow for 10 days prior to surgical resection. Rats were given either surgical resection only, bolus injection (100 microg) or microspheres containing 10, 50, or 100 microg of carboplatin or BCNU. The microspheres were implanted, via hypodermic injection, either directly into the surgical cavity or into the tissue along the perimeter of the cavity. RESULTS: The order of survival among treatment groups was: no resection < resection only < bolus chemotherapy < sustained release chemotherapy. Carboplatin and BCNU did not differ in this respect and in each case, the enhanced survival achieved with sustained release was dose-related. However, the enhanced survival achieved with carboplatin was substantially greater when the microspheres were implanted into the perimeter wall of the resection cavity, compared to implantation into the cavity itself. The enhanced survival produced by carboplatin implants along the resection perimeter was associated with a significant attenuation of regrowth of the tumor. Finally, in a separate study in non-tumor brain, atomic absorption spectrophotometry revealed that while the microspheres produced significantly prolonged tissue levels of carboplatin relative to a bolus injection, carboplatin diffusion was limited to brain tissue extending primarily 0.5 mm from the injection site. CONCLUSIONS: These data demonstrate: (1) that sustained delivery of chemotherapy is superior to equipotent bolus doses following tumor resection, and (2) that direct injection of sustained release microspheres into the tissue surrounding a growing tumor mass may provide superior effects over injections into the surgical cavity. They also suggest that successful implementation of this approach in humans may require measures or circumstances that improve upon the limited spatial drug diffusion from the implantation site.

Cereport (RMP-7) increases carboplatin levels in brain tumors after pretreatment with dexamethasone.

Accumulating evidence suggests that dexamethasone might decrease permeability of the blood-brain tumor barrier, further limiting the delivery of agents into brain tumors. The bradykinin B2 receptor agonist, Cereport (RMP-7), selectively increases permeability of the vasculature supplying brain tumors in both animal models and humans. The present study was conducted to characterize the effects of dexamethasone on the blood-brain tumor barrier and its potential interaction with Cereport's ability to enhance penetration of radiolabeled carboplatin. Dexamethasone (1.5 mg/kg/day, twice a day) was given to RG2 glioma-bearing rats via oral gavage for 3 consecutive days. After treatment, animals received a 15-min intracarotid infusion of Cereport (4.5 micrograms/kg) and a bolus of [14C]carboplatin. The levels of [14C]carboplatin (nCi/g) in the tumor and nontumor regions were determined at 1, 14, or 24 h after the last dose of dexamethasone. Dexamethasone, alone, significantly decreased the levels of radiolabeled carboplatin permeating the tumor (19%), although there were no significant differences between any of the time points examined. Cereport administration significantly increased levels of carboplatin in the tumor, independent of whether or not dexamethasone was given (46% with and 49% without). Although the relative effects of Cereport on tumor carboplatin levels were not affected by dexamethasone, the absolute levels achieved with Cereport were modestly reduced (44 nCi/g versus 55.5 nCi/g of [14C]carboplatin, with and without dexamethasone, respectively). Thus, while the data support the use of Cereport as adjunctive therapy in the treatment of glioma patients, they also warn that the use of dexamethasone may reduce delivery of chemotherapeutic agents to brain tumors, even when special pharmacologic measures are employed to enhance delivery.