Assessing Free-Living Postural Sway in Persons With Multiple Sclerosis.

Postural instability is associated with disease status and fall risk in Persons with Multiple Sclerosis (PwMS). However, assessments of postural instability, known as postural sway, leverage force platforms or wearable accelerometers, and are most often conducted in laboratory environments and are thus not broadly accessible. Remote measures of postural sway captured during daily life may provide a more accessible alterative, but their ability to capture disease status and fall risk has not yet been established. We explored the utility of remote measures of postural sway in a sample of 33 PwMS. Remote measures of sway differed significantly from lab-based measures, but still demonstrated moderately strong associations with patient-reported measures of balance and mobility impairment. Machine learning models for predicting fall risk trained on lab data provided an Area Under Curve (AUC) of 0.79, while remote data only achieved an AUC of 0.51. Remote model performance improved to an AUC of 0.74 after a new, subject-specific k-means clustering approach was applied for identifying the remote data most appropriate for modelling. This cluster-based approach for analyzing remote data also strengthened associations with patient-reported measures, increasing their strength above those observed in the lab. This work introduces a new framework for analyzing data from remote patient monitoring technologies and demonstrates the promise of remote postural sway assessment for assessing fall risk and characterizing balance impairment in PwMS.

Digital Phenotypes of Instability and Fatigue Derived From Daily Standing Transitions in Persons With Multiple Sclerosis.

Impairment in persons with multiple sclerosis (PwMS) can often be attributed to symptoms of motor instability and fatigue. Symptom monitoring and queued interventions often target these symptoms. Clinical metrics are currently limited to objective physician assessments or subjective patient reported measures. Recent research has turned to wearables for improving the objectivity and temporal resolution of assessment. Our group has previously observed wearable assessment of supervised and unsupervised standing transitions to be predictive of fall-risk in PwMS. Here we extend the application of standing transition quantification to longitudinal home monitoring of symptoms. Subjects (N=23) with varying degrees of MS impairment were recruited and monitored with accelerometry for a total of  âˆ¼  6 weeks each. These data were processed using a preexisting framework, applying a deep learning activity classifier to isolate periods of standing transition from which descriptive features were extracted for analysis. Participants completed daily and biweekly assessments describing their symptoms. From these data, Canonical Correlation Analysis was used to derive digital phenotypes of MS instability and fatigue. We find these phenotypes capable of distinguishing fallers from non-fallers, and further that they demonstrate a capacity to characterize symptoms at both daily and sub-daily resolutions. These results represent promising support for future applications of wearables, which may soon augment or replace current metrics in longitudinal monitoring of PwMS.

Chest-Based Wearables and Individualized Distributions for Assessing Postural Sway in Persons With Multiple Sclerosis.

Typical assessments of balance impairment are subjective or require data from cumbersome and expensive force platforms. Researchers have utilized lower back (sacrum) accelerometers to enable more accessible, objective measurement of postural sway for use in balance assessment. However, new sensor patches are broadly being deployed on the chest for cardiac monitoring, opening a need to determine if measurements from these devices can similarly inform balance assessment. Our aim in this work is to validate postural sway measurements from a chest accelerometer. To establish concurrent validity, we considered data from 16 persons with multiple sclerosis (PwMS) asked to stand on a force platform while also wearing sensor patches on the sacrum and chest. We found five of 15 postural sway features derived from the chest and sacrum were significantly correlated with force platform-derived features, which is in line with prior sacrum-derived findings. Clinical significance was established using a sample of 39 PwMS who performed eyes-open, eyes-closed, and tandem standing tasks. This cohort was stratified by fall status and completed several patient-reported measures (PRM) of balance and mobility impairment. We also compared sway features derived from a single 30-second period to those derived from a one-minute period with a sliding window to create individualized distributions of each postural sway feature (ID method). We find traditional computation of sway features from the chest is sensitive to changes in PRMs and task differences. Distribution characteristics from the ID method establish additional relationships with PRMs, detect differences in more tasks, and distinguish between fall status groups. Overall, the chest was found to be a valid location to monitor postural sway and we recommend utilizing the ID method over single-observation analyses.

How Much Data Is Enough? A Reliable Methodology to Examine Long-Term Wearable Data Acquisition in Gait and Postural Sway.

Wearable sensors facilitate the evaluation of gait and balance impairment in the free-living environment, often with observation periods spanning weeks, months, and even years. Data supporting the minimal duration of sensor wear, which is necessary to capture representative variability in impairment measures, are needed to balance patient burden, data quality, and study cost. Prior investigations have examined the duration required for resolving a variety of movement variables (e.g., gait speed, sit-to-stand tests), but these studies use differing methodologies and have only examined a small subset of potential measures of gait and balance impairment. Notably, postural sway measures have not yet been considered in these analyses. Here, we propose a three-level framework for examining this problem. Difference testing and intra-class correlations (ICC) are used to examine the agreement in features computed from potential wear durations (levels one and two). The association between features and established patient reported outcomes at each wear duration is also considered (level three) for determining the necessary wear duration. Utilizing wearable accelerometer data continuously collected from 22 persons with multiple sclerosis (PwMS) for 6 weeks, this framework suggests that 2 to 3 days of monitoring may be sufficient to capture most of the variability in gait and sway; however, longer periods (e.g., 3 to 6 days) may be needed to establish strong correlations to patient-reported clinical measures. Regression analysis indicates that the required wear duration depends on both the observation frequency and variability of the measure being considered. This approach provides a framework for evaluating wear duration as one aspect of the comprehensive assessment, which is necessary to ensure that wearable sensor-based methods for capturing gait and balance impairment in the free-living environment are fit for purpose.

Relative Bioavailability of Budesonide/Glycopyrrolate/Formoterol Fumarate Metered Dose Inhaler Administered With and Without a Spacer: Results of a Phase I, Randomized, Crossover Trial in Healthy Adults.

PURPOSE: The triple combination therapy budesonide/glycopyrrolate/formoterol fumarate in a metered dose inhaler (BGF MDI), formulated by using innovative co-suspension delivery technology, is a new inhaled corticosteroid/long-acting muscarinic antagonist/long-acting ß2-agonist fixed-dose combination for the maintenance treatment of COPD. For some patients, the use of an MDI may be optimized with a spacer. This Phase I study assessed the effect of a spacer on lung exposure, total systemic exposure, and safety of BGF MDI 320/36/9.6 µg in healthy subjects. METHODS: This randomized, open-label, crossover study assessed the pharmacokinetic and safety profiles of BGF MDI in healthy adult subjects who received a single dose of BGF MDI 320/36/9.6 µg (administered as 2 inhalations with 160/18/4.8 µg per actuation) in 4 regimens: without spacer and no charcoal; with spacer and no charcoal; without spacer and with charcoal; and with spacer and with charcoal. Primary objectives were to assess total systemic exposure (without charcoal) and lung exposure (with charcoal) of budesonide, glycopyrronium, and formoterol administered as BGF MDI with and without a spacer. Safety was also assessed. FINDINGS: In total, 56 subjects were randomized (mean age, 29.9 years; 60.7% male, 17.9% former smokers). For systemic exposure (without charcoal), the spacer/without spacer ratio, expressed as a percentage (intrasubject %CV) of Cmax and AUC0-tlast, respectively, was 152.0 (47.5) and 132.8 (43.6) for budesonide, 240.6 (80.2) and 154.7 (73.4) for glycopyrronium, and 165.6 (50.7) and 98.6 (53.8) for formoterol. For lung exposure (with charcoal), the spacer/without spacer ratio percentage (%CV) of Cmax and AUC0-tlast, respectively, was 183.6 (65.9) and 198.4 (71.5) for budesonide, 262.0 (91.8) and 373.9 (120.7) for glycopyrronium, and 222.9 (56.3) and 385.2 (147.0) for formoterol. Subjects who were judged to have suboptimal inhalation technique without a spacer (those in the lowest drug exposure quartile based on AUC0-tlast) had the greatest increase in both total systemic and lung exposure when a spacer was used versus no spacer. Subjects in the highest quartile had a minimal change in both total systemic and lung exposure when the spacer was used. Treatment-emergent adverse events (TEAEs) (all mild/moderate) reported by >1 subject per regimen were headache, cough, and dizziness. One subject withdrew because of TEAEs of headache and presyncope (neither considered treatment-related). IMPLICATIONS: Drug delivery can be improved for subjects with suboptimal MDI inhalation technique when using a spacer device with BGF MDI triple therapy. ClinicalTrials.gov identifier: NCT03311373.

Pharmacokinetics of Co-Suspension Delivery Technology Budesonide/Glycopyrronium/Formoterol Fumarate Dihydrate (BGF MDI) and Budesonide/Formoterol Fumarate Dihydrate (BFF MDI) Fixed-Dose Combinations Compared With an Active Control: A Phase 1, Randomized, Single-Dose, Crossover Study in Healthy Adults.

This randomized, phase 1, single-dose, crossover study (NCT02189304) compared the 12-hour pharmacokinetic (PK) and safety profiles of budesonide/glycopyrronium/formoterol fumarate dihydrate metered dose inhaler (BGF MDI) 320/14.4/10 µg and budesonide/formoterol fumarate dihydrate (BFF) MDI 320/10 µg (both formulated using innovative co-suspension delivery technology) to an active comparator (budesonide/formoterol fumarate dihydrate dry powder inhaler [BUD/FORM DPI] 320/9-µg delivered dose) in healthy adults. The potential for PK interaction between glycopyrronium and budesonide/formoterol within BGF MDI was assessed. Of 72 subjects randomized, 59 completed treatment. Systemic budesonide exposure (primary objective) based on area under the plasma drug concentration-time curve 0-12 hours (AUC0-12 ; % coefficient of variation) was 1598.38 (49.7), 1657.09 (50.4), and 1276.75 (70.4) pg·h/mL for BGF MDI, BFF MDI, and BUD/FORM DPI, respectively; and formoterol exposure (AUC0-12 [% coefficient of variation]) was 39.16 (45.9), 39.53 (40.5), and 23.24 (59.2) pg·h/mL, respectively. BGF MDI and BFF MDI were bioequivalent for budesonide and formoterol. All treatments were well tolerated. While systemic exposure to budesonide and formoterol was higher for BGF MDI and BFF MDI than for BUD/FORM DPI, there were no appreciable differences in the incidence of pharmacologically predictable adverse events. This, coupled with the absence of PK interactions, suggests the BGF MDI safety profile will be comparable to BUD/FORM DPI.

Pharmacokinetics and safety of a single dose of the novel LAMA/LABA fixed-dose combination of glycopyrronium/formoterol fumarate dihydrate metered dose inhaler, formulated using co-suspension delivery technology, in Japanese healthy subjects.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) causes significant mortality in Japan. GFF MDI is a long-acting muscarinic antagonist/long-acting ß2-agonist fixed-dose combination of glycopyrronium (GP) and formoterol fumarate dihydrate (FF), delivered by a metered dose inhaler (MDI) using co-suspension delivery technology, for the long-term maintenance treatment of COPD. METHODS: This randomized, Phase I, single-dose, four-treatment, four-period, crossover study (NCT02196714) examined the pharmacokinetic (PK) and safety profile of two doses of GFF MDI (28.8 µg/10 µg and 14.4 µg/10 µg) and two doses of GP MDI (28.8 µg and 14.4 µg), both formulated using co-suspension delivery technology, in healthy Japanese subjects (18-45 years of age). PK parameters included area under the curve (AUC) from 0 to 12 h (AUC0-12), AUC from 0 to the time of the last measurable plasma concentration, maximum observed plasma concentration (Cmax), and time to Cmax. Safety was monitored throughout the study. RESULTS: Plasma GP profiles were comparable between GFF MDI and GP MDI formulations containing the same GP dose. Increases in GP AUC0-12 and Cmax were generally dose proportional from 14.4 to 28.8 µg after administration of either formulation. CONCLUSIONS: The addition of FF 10 µg to GP MDI 28.8 µg or 14.4 µg in a fixed-dose combination did not appreciably alter the PK of GP, nor did an increase in GP dose from 14.4 µg to 28.8 µg in a fixed-dose combination with FF 10 µg appreciably alter the PK of formoterol. Both formulations of GFF MDI and GP MDI were well tolerated in healthy Japanese subjects. Data from this study support further evaluation of GFF MDI in Japanese patients with COPD.

Safety and pharmacokinetics of budesonide/glycopyrronium/formoterol fumarate dihydrate metered dose inhaler (BGF MDI) in healthy adult subjects of Japanese descent.

INTRODUCTION: BGF MDI, a budesonide, glycopyrronium, and formoterol fumarate dihydrate triple fixed-dose combination metered dose inhaler formulated using co-suspension delivery technology, is currently in Phase III global development for chronic obstructive pulmonary disease. METHODS: This was a Phase I, randomized, double-blind, placebo-controlled, ascending-dose, crossover study to assess the safety and pharmacokinetic profiles of two doses of BGF MDI in healthy adult subjects of Japanese descent (NCT02197975). Safety assessments included monitoring for adverse events (AEs). Pharmacokinetic parameters were assessed following a single dose and 7-days chronic dosing with BGF MDI 160/14.4/10 µg and BGF MDI 320/14.4/10 µg. RESULTS: Twenty subjects were randomized and included in the safety and pharmacokinetic populations; mean age 29.7 years; 65% male; and mean body mass index of 21.9 kg/m2. The incidences of treatment-emergent AEs (TEAEs) were similar between treatments. All the TEAEs were mild to moderate in severity. Budesonide area under the plasma concentration-time curve from 0 to 12 h (AUC0-12) and maximum observed plasma concentration (Cmax) values were approximately double for the higher dose of BGF MDI compared with the lower dose on Day 1 and also following chronic dosing on Day 8. Glycopyrronium and formoterol AUC0-12 and Cmax values on Day 8 were comparable between the two doses of BGF MDI. DISCUSSION: Both doses of BGF MDI were well tolerated in healthy subjects of Japanese descent and the systemic exposure to budesonide was dose proportional for BGF MDI 160/14.4/10 µg and BGF MDI 320/14.4/10 µg. The safety and pharmacokinetics for BGF MDI 160/14.4/10 µg and BGF MDI 320/14.4/10 µg in Japanese subjects were comparable to data from previous studies in Western populations, which suggests that the safety and efficacy profile of BGF MDI should be similar in Western and Japanese subjects.

The pharmacokinetics of three doses of budesonide/glycopyrronium/formoterol fumarate dihydrate metered dose inhaler compared with active controls: A Phase I randomized, single-dose, crossover study in healthy adults.

The budesonide/glycopyrronium/formoterol fumarate dihydrate metered dose inhaler (BGF MDI) is an inhaled corticosteroid/long-acting muscarinic antagonist/long-acting ß2-agonist fixed-dose combination formulated with innovative co-suspension delivery technology that is in clinical development for the treatment of chronic obstructive pulmonary disease (COPD). This randomized, Phase I, single-dose, six-treatment, four-period, crossover study (NCT01980615) examined the pharmacokinetic (PK) and safety profile of three doses of BGF MDI (320/14.4/10 µg [equivalent to budesonide/glycopyrrolate/formoterol fumarate 320/18/9.6 µg], 160/14.4/10 µg and 80/14.4/10 µg), two doses of a budesonide/formoterol fumarate dihydrate fixed-dose combination (BUD/FORM MDI 320/9 µg and 160/9 µg; not using co-suspension delivery technology) and a glycopyrronium/formoterol fumarate dihydrate co-suspension delivery technology MDI (GFF MDI 14.4/10 µg) in healthy volunteers (18-45 years of age). PK parameters included area under the plasma concentration-time curve from 0 to 12 h (AUC0-12), AUC up to the last measurable concentration (AUC0-t), maximum plasma concentration (Cmax) and time to maximum plasma concentration (tmax). Safety was monitored throughout the study. Of 84 subjects randomized, 76 completed the study. BGF MDI 320/14.4/10 µg was bioequivalent to BUD/FORM MDI 320/9 µg for budesonide for Cmax, AUC0-12 and AUC0-t (primary objective). Dose proportionality was observed for the budesonide component between BGF MDI 80/14.4/10 µg and BGF MDI 160/14.4/10 µg, and between BGF MDI 160/14.4/10 µg and BGF MDI 320/14.4/10 µg. Systemic exposure to glycopyrronium and formoterol after BGF MDI 320/14.4/10 µg treatment was similar to GFF MDI 14.4/10 µg. The rate of adverse events was 3.7-17.9% across treatments without any serious adverse events. In conclusion, BGF MDI 320/14.4/10 µg had a similar budesonide PK profile to BUD/FORM MDI 320/9 µg. No PK drug-drug interactions were observed when budesonide was added to glycopyrronium and formoterol fumarate dihydrate. These data support the use of budesonide 320 µg and 160 µg in future clinical trials of BGF MDI in COPD.

Cardiovascular safety profile of a fixed-dose combination of glycopyrrolate and formoterol fumarate delivered via metered dose inhaler using co-suspension delivery technology.

BACKGROUND: Glycopyrrolate/formoterol fumarate (GFF) metered dose inhaler (MDI) is a fixed-dose combination of the long-acting muscarinic antagonist (LAMA), glycopyrrolate (GP), and the long-acting ß2-agonist (LABA), formoterol fumarate (FF), delivered via metered dose inhaler using innovative co-suspension delivery technology. Here we report the results of two studies that examined the cardiovascular safety of GFF MDI. METHODS: The thorough QT (TQT) study was a Phase I, randomized, double-blind, single-dose, crossover study to assess GFF MDI 18/9.6 (Bevespi Aerosphere®), GFF MDI 144/38.4 and GP MDI 144 µg, compared with placebo MDI and open-label moxifloxacin 400 mg (active control) in healthy volunteers (PT003009). The cardiovascular safety study in patients with chronic obstructive pulmonary disease (COPD) was a Phase IIb, randomized, multicenter, double-blind, 14-day dosing, parallel-group study to evaluate GFF MDI 36/9.6, GP MDI 36 and FF MDI 9.6 µg compared with open-label FF dry powder inhaler (DPI; Foradil® Aerolizer®) 12 µg, in patients with moderate-to-severe COPD (PT003003 [NCT01349803]). RESULTS: Seventy healthy volunteers were randomized in the TQT study. GFF MDI 144/38.4, GFF MDI 18/9.6 and GP MDI 144 µg all met the confidence interval-based criteria for negative QT prolongation potential. In the study in patients with COPD, 237 subjects were randomized and treated. GFF MDI 36/9.6, GP MDI 36, and FF MDI 9.6 µg did not result in clinically meaningful changes from baseline in 24-h mean heart rate at Day 14 (primary endpoint) or in any of the other Holter monitoring endpoints at Day 14, compared with FF DPI 12 µg. CONCLUSIONS: No clinically significant effects on cardiovascular safety occurred at therapeutic or supratherapeutic doses of GFF MDI, apart from a small and transient increase in heart rate following supratherapeutic dose of GFF MDI 144/38.4 µg. Furthermore, there were no unexpected safety findings reported in either healthy volunteers or patients with COPD.

A wearable computing platform for developing cloud-based machine learning models for health monitoring applications.

Wearable sensors have the potential to enable clinical-grade ambulatory health monitoring outside the clinic. Technological advances have enabled development of devices that can measure vital signs with great precision and significant progress has been made towards extracting clinically meaningful information from these devices in research studies. However, translating measurement accuracies achieved in the controlled settings such as the lab and clinic to unconstrained environments such as the home remains a challenge. In this paper, we present a novel wearable computing platform for unobtrusive collection of labeled datasets and a new paradigm for continuous development, deployment and evaluation of machine learning models to ensure robust model performance as we transition from the lab to home. Using this system, we train activity classification models across two studies and track changes in model performance as we go from constrained to unconstrained settings.

A stretchable and flexible system for skin-mounted measurement of motion tracking and physiological signals.

In this paper, we present a stretchable wearable system capable of i) measuring multiple physiological parameters and ii) transmitting data via radio frequency to a smart phone. The electrical architecture consists of ultra thin sensors (<; 20 µm thick) and a conformal network of associated active and passive electronics in a mesh-like geometry that can mechanically couple with the curvilinear surfaces of the human body. Spring-like metal interconnects between individual chips on board the device allow the system to accommodate strains approaching ~30% A representative example of a smart patch that measures movement and electromyography (EMG) signals highlights the utility of this new class of medical skin-mounted system in monitoring a broad range of neuromuscular and cardiovascular diseases.

Serum 25-hydroxyvitamin d and the incidence of acute viral respiratory tract infections in healthy adults.

BACKGROUND: Declining serum concentrations of 25-hydroxyvitamin D seen in the fall and winter as distance increases from the equator may be a factor in the seasonal increased prevalence of influenza and other viral infections. This study was done to determine if serum 25-hydroxyvitamin D concentrations correlated with the incidence of acute viral respiratory tract infections. METHODOLOGY/FINDINGS: In this prospective cohort study serial monthly concentrations of 25-hydroxyvitamin D were measured over the fall and winter 2009-2010 in 198 healthy adults, blinded to the nature of the substance being measured. The participants were evaluated for the development of any acute respiratory tract infections by investigators blinded to the 25-hydroxyvitamin D concentrations. The incidence of infection in participants with different concentrations of vitamin D was determined. One hundred ninety-five (98.5%) of the enrolled participants completed the study. Light skin pigmentation, lean body mass, and supplementation with vitamin D were found to correlate with higher concentrations of 25-hydroxyvitamin D. Concentrations of 38 ng/ml or more were associated with a significant (p<0.0001) two-fold reduction in the risk of developing acute respiratory tract infections and with a marked reduction in the percentages of days ill. CONCLUSIONS/SIGNIFICANCE: Maintenance of a 25-hydroxyvitamin D serum concentration of 38 ng/ml or higher should significantly reduce the incidence of acute viral respiratory tract infections and the burden of illness caused thereby, at least during the fall and winter in temperate zones. The findings of the present study provide direction for and call for future interventional studies examining the efficacy of vitamin D supplementation in reducing the incidence and severity of specific viral infections, including influenza, in the general population and in subpopulations with lower 25-hydroxyvitamin D concentrations, such as pregnant women, dark skinned individuals, and the obese.

Differential effects of MK801 and lorazepam on heart rate variability in adolescent rhesus monkeys (macaca mulatta).

Previous research shows that ketamine significantly alters cardiac signal regulation in rhesus monkeys, however relatively little is known about the mechanism for this effect. In the study reported here the relative contributions of NMDA receptor activation on cardiac signal dynamics were determined by administering a specific NMDA antagonist, MK801, to rhesus monkeys. The general effects of sedation were assessed by measuring cardiac response to lorazepam, a sedative drug without direct NMDA receptor activity. Electrocardiographic signal dynamics were examined before and after I.V. administration of either MK801 (0.16 mg/kg) or lorazepam (0.48 mg/kg). Inter-beat interval time series data were analyzed in the frequency domain after Fourier transform, and a nonlinear measure of autocorrelation, the Hurst exponent (H), was derived. After MK801 administration, log [HF /Total power] increased post-infusion (M = 1.11, SD = 0.45) compared with pre-infusion values [M = -0.19, SD = 0.32, F(1,4) = 19.49, P = 0.01] while H decreased, mean pre versus post 0.52+/-S.D. 0.10 versus 0.01+/- 0.05, P = 0.0002. Lorazepam administration did not significantly alter heart rate variability measures obtained in the frequency or nonlinear domains. To our knowledge, this is the first study that has defined the effects of peripherally administered MK801 on cardiovascular dynamics in primates and establishes that peripheral administration of NMDA antagonists result in large increases the high-frequency components of cardiac rhythm and increased heart rate variability compatible with MK801-associated increases in parasympathetic outflow.

Serotonin transporter promoter polymorphism and monoamine oxidase type A VNTR allelic variants together influence alcohol binge drinking risk in young women.

The short allelic variant of the serotonin transporter protein promoter polymorphism (5HTTLPR) appears to influence binge drinking in college students. Both monoamine oxidase type A (MAOA) and the serotonin transporter protein are involved in the processing of serotonin, and allelic variants are both associated with differences in the efficiency of expression. We hypothesized that a significant gene x gene interaction would further stratify the risk of binge drinking in this population. Participants were college students (n = 412) who completed the College Alcohol Study, used to measure binge drinking behaviors. Genomic DNA was extracted from saliva for PCR based genotyping. The risk function for binge drinking was modeled using logistic regression, with final model fit P < 0.0005. This model was valid only for Caucasian females (n = 223), but the power to detect sex and ethnic effects was small. Young Caucasian women carrying higher expression MAOA VNTR alleles homozygous for the short allelic variant of the 5HTTLPR demonstrated the highest rate of binge drinking by self-report, odds ratio (genotype odds: population odds) and 95% confidence intervals, 3.11 (1.14-18.10). Individuals carrying higher expression MAOA VNTR alleles carrying at least one long 5HTTLPR allelic variant had the lowest risk of binge drinking 0.46 (0.28-0.71). These results support the hypothesis that binge drinking behavior in young adulthood may be influenced by neurobiological differences in serotonergic function conferred by functional polymorphisms in genes involved in serotonin processing.

Sex differences in total body water in adolescent rhesus macaques estimated by ethanol dilution.

Non-human primates are widely used in research, yet relatively few studies have addressed potential pharmacokinetic differences between males and females. The present study examined the relationship between total body water, sex, age, and weight in the rhesus macaque (Macaca mulatta). Ethanol-naïve, adolescent rhesus macaques (n = 119) were administered ethanol (males, 2.1 g/kg; females, 2.0 g/kg) intravenously, and blood samples for blood ethanol concentration obtained at 5, 10, and 60 minutes following the end of the infusion. Non-linear regression was used to compare and contrast a series of pharmacokinetic models examining the relationship between weight, sex, age, V(d) and zero-order elimination rate. V(d) (mean +/- SEM) for male rhesus was 0.771 +/- 0.008 l/kg and for females was 0.730 +/- 0.008 l/kg, different at P < 0.00001. There were no sex differences in the rate of zero-order ethanol elimination, estimated to be 0.0032 +/- 0.0004 g/kg/minute. The data reported here may be useful in designing and interpreting pharmacokinetic studies using rhesus monkeys.

Serotonin transporter promoter polymorphism and differences in alcohol consumption behaviour in a college student population.

AIMS AND METHODS: In the present study, differences in alcohol consumption behaviour associated with the presence of the short variant (S) of the serotonin transporter promoter polymorphism (5-HTTLPR) was investigated in a Caucasian subset (n = 204) of 268 college students. RESULTS: Students who were homozygous for the S allele were more likely to engage in binge-drinking behaviour, drank more alcohol per occasion, and reported drinking to get drunk more often. CONCLUSIONS: In this Caucasian sample, the 5-HTTLPR strongly influences alcohol consumption in late pubescence.

Corticosterone increases serotonin type-3 receptor mRNA in rat pheochromocytoma-12 cells.

Serotonin type-3 (5-HT3) receptors are cation permeable membrane receptors which are involved in modulation of calcium entry in neuronal cells. Along with other ion-channels such as the N-methyl-D-aspartate receptor, it appears to be a target for the actions of ethanol and has been the focus of considerable work in this regard. Since in animals, ethanol exposure results in elevations of corticosteroids in both acute and chronic conditions, we studied the effects of both ethanol and corticosteroid exposure on 5-HT3 gene expression in an in situ pheochromocytoma-12 (PC12) cell model. We found that ethanol exposure alone (80 mMx4 days) did not significantly alter target gene expression. Corticosterone (CORT) (50, 150, and 300 ng/ml) resulted in significant increases in 5-HT3 expression which were attenuated by mifeprestone (50 ng/ml). Ethanol in combination with CORT did not significantly alter the increase in 5- HT3 mRNA seen with CORT alone. We conclude that in PC12 cells, exposure to CORT at physiologically relevant concentrations increases 5-HT3 gene expression.

Ritonavir protects hippocampal neurons against oxidative stress-induced apoptosis.

Oxidative stress plays an important role in many neurodegenerative conditions including Alzheimer's disease and Parkinson's disease. 4-Hydroxynonenal (HNE), a lipid-soluble aldehydic product of membrane peroxidation, has been known to decrease neuronal survival by impairing Na+, K+, and -ATPase activity. HNE also increases neuronal vulnerability to excitotoxic injury and disrupts homeostasis by activating proteases which mediate the destruction of cellular protein and structure. The present study demonstrated that the hydrophobic HIV protease inhibitor, ritonavir inhibited HNE-mediated apoptosis in hippocampal primary neurons. In neurons exposed to oxidative stress induced by HNE (1 microM), ritonavir at 100 pM increased cell survival and completely abolished the apoptotic effects of HNE (P < 0.01). Ritonavir and its analogues might have useful cytoprotective effects for use in limiting the natural course of tissue injury after conditions where oxidative stress plays a role.

Ritonavir inhibition of calcium-activated neutral proteases.

Calpains (EC 3.4.22.17) are intracellular calcium-activated cysteine proteases that mediate tissue injury following post-ischemic and post-traumatic stress. Both human HIV protease and calpains share a similar secondary structure, where the active site is flanked by hydrophobic regions. The present study demonstrates that ritonavir, a hydrophobic HIV protease inhibitor, also inhibits calpain activity. In PC12 cell extracts assayed for calpain at maximal activity (2mM calcium), ritonavir exhibited competitive inhibition with a K(i) of 11+/-7.0 microM. Experiments with purified enzymes showed inhibition for both m- and mu-calpain isoforms (m-calpain, K(i)=9.2+/-1.2 microM; mu-calpain, K(i)=5.9+/-1.4 microM). Ritonavir also inhibited calcium-stimulated calpain activity in PC12 cells in situ. These results suggest that ritonavir or analogues of the drug should be investigated as cytoprotective agents in conditions where cell death or injury is mediated via calpain activation.