A Portable Analyzer for Pouch-Actuated, Immunoassay Cassettes.

A portable, small footprint, light, general purpose analyzer (processor) to control the flow in immunoassay cassettes and to facilitate the detection of test results is described. The durable analyzer accepts disposable cassettes that contain pouches and reaction chambers for various unit operations such as hydration of dry reagents, stirring, and incubation. The analyzer includes individually controlled, linear actuators to compress the pouches in the cassette, which facilitates the pumping and mixing of sample and reagents, and to close diaphragm-based valves for flow control. The same types of actuators are used to compress pouches and actuate valves. The analyzer also houses a compact OEM scanner/reader to excite fluorescence and detect emission from labels. The analyzer is hydraulically isolated from the cassette, reducing the possibility of cross-contamination. The analyzer facilitates programmable, automated execution of a sequence of operations such as pumping and valving in a timely fashion, reducing the level of expertise required from the operator and the possibility for errors. The analyzer's design is modular and expandable to accommodate cassettes of various complexities and additional functionalities. In this paper, the utility of the analyzer has been demonstrated with the execution of a simple, consecutive, lateral flow assay of a model biological system and the test results were detected with up converting phosphor labels that are excited at infrared frequencies and emit in the visible spectrum.

Characterization of sandwich-cultured hepatocytes as an in vitro model to assess the hepatobiliary disposition of copper.

Sandwich-cultured hepatocytes (SCH) from rats (SCRH), dogs (SCDH), and humans (SCHH) were used as an in vitro model to assess the hepatobiliary disposition of copper (Cu). The expression of Cu transporters, ceruloplasmin synthesis, Cu uptake, and biliary excretion and species differences in drug-induced alterations in Cu disposition were determined in SCH from all species. Western blot analysis verified basolateral Cu uptake transporter 1 (CTR1) and canalicular Cu efflux transporter (ATP7B) expression: enzyme-linked immunosorbent assay verified synthesis/secretion of ceruloplasmin (major Cu binding protein found in blood). Endogenous Cu in SCRH, SCDH, and SCHH were 17.2 +/- 7.00, 490 +/- 44.8, and 43.5 +/- 15.8 ng/well, respectively. The hepatobiliary disposition of Cu as measured by uptake (increase in intracellular Cu in comparison to endogenous levels) and biliary excretion (increase in Cu in wash solutions obtained from hepatocytes exposed to calcium-free versus standard buffer) was determined as a function of Cu concentration and incubation time. In general, an increase in Cu concentration or incubation time resulted in an increase in Cu uptake and/or biliary excretion; however, the extent to which they affected Cu disposition was species dependent. 5-(1,1-Dioxido-1,2-thiazinan-2-yl)-N-(4-fluorobenzyl)-8-hydroxy-1,6-naphthyridine-7-carboxamide (L-000870810) (an anti-HIV compound, the development of which was halted due to an observed Cu-specific toxicity in the liver and kidneys of dogs after long-term exposure) showed no effect on Cu disposition in SCRH; however, it increased the biliary excretion of Cu in SCDH and SCHH. This is the first report to demonstrate the utility of SCH as a model to assess hepatobiliary disposition of Cu in an in vitro system.

A multicenter, prospective study of a novel nasal EPAP device in the treatment of obstructive sleep apnea: efficacy and 30-day adherence.

STUDY OBJECTIVES: Evaluate the efficacy of a novel device placed in the nares that imposes an expiratory resistance for the treatment of obstructive sleep apnea (OSA) and evaluate adherence to the device over a 30-day in-home trial period. DESIGN: One diagnostic and 3 treatment polysomnograms were administered in a Latin-square design to identify the optimal expiratory resistance to be used during the 30-day in-home trial. Subjects had repeat polysomnography with the prescribed device at the end of the 30-day trial. SETTING: Multicenter study. PARTICIPANTS: Participants (N=34; age 27 to 67) with a baseline apnea-hypopnea index (AHI) > or =5. MEASUREMENTS AND RESULTS: The AHI was reduced from 24.5 _ 23.6 (mean +/- SD) to an average of 13.5 +/- 18.7 (p < 0.001) across initial treatment nights. The AHI was 15.5 +/-+/- 18.9 (p = 0.001) for the prescribed device at the end of the 30-day trial. Of 24 subjects with an AHI > 10 at baseline, 13 achieved an AHI < 10 on the initial treatment nights; 10 had a similar response on the final treatment night. Percent of the night snoring decreased from 27.5 +/- 23.2 to 11.6 +/- 13.7 (p < 0.001) on initial treatment nights and 14.6 +/- 20.6 (p = 0.013) at the end of the trial; Epworth Sleepiness scores decreased from 8.7 +/- 4.0 at baseline to 6.9 +/- 4.4 (p < 0.001) at the end of the trial; the Pittsburgh Sleep Quality Index improved from 7.4 +/- 3.3 to 6.5 +/- 3.6 (p = 0.042). Mean oxygen saturation increased from 94.8 +/- 2.0 to 95.2 +/- 1.9 (p = 0.023) on initial treatment nights and 95.3 +/- 1.9 (p = 0.003) at the end of the trial. Sleep architecture was not affected. Participants reported using the device all night long for 94% of nights during the in-home trial. CONCLUSIONS: Treatment with this novel device was well tolerated and accepted by the participants. An overall reduction in AHI was documented; however, therapeutic response was variable among the participants. Further research is required to identify the ideal candidates for this new therapeutic option in the management of OSA.

Enoxaparin thromboprophylaxis in gastric bypass patients: extended duration, dose stratification, and antifactor Xa activity.

BACKGROUND: Morbidly obese patients undergoing gastric bypass surgery are at risk for postoperative venous thromboembolism. Evidence-based recommendations regarding the dosing and duration of thromboprophylaxis are lacking for morbidly obese surgical patients. The aims of this study were to evaluate the safety and efficacy of an extended duration, body mass index (BMI)-stratified enoxaparin thromboprophylaxis regimen in patients undergoing Roux-en-Y gastric bypass and to determine the resultant antifactor Xa (AFXa) activity in morbidly obese surgical patients. METHODS: In this prospective open trial, 223 patients (75% female, mean BMI 50.4 kg/m2) undergoing Roux-en-Y gastric bypass were assigned to receive enoxaparin 40 mg (BMI 50 kg/m2), n = 99) every 12 hours during hospitalization and once daily for 10 days after discharge. The AFXa levels were monitored serially, and dose adjustments were made for results outside the target prophylactic range (.2-.4 IU/mL +/- 10%) after the third dose. The safety and efficacy outcomes were major bleeding and venous thromboembolism. RESULTS: Roux-en-Y gastric bypass was performed laparoscopically in 208 subjects (93%). The duration of surgery averaged 99.5 +/- 31 minutes, and the median length of hospitalization was 3 days. Target prophylactic AFXa concentration was achieved by 74% of patients after the third enoxaparin dose; none reached the full anticoagulation concentration. One patient developed nonfatal venous thromboembolism (.45%). Four patients required transfusion (1.79%). Bleeding was not associated with a high AFXa concentration. CONCLUSION: This BMI-stratified, extended enoxaparin dosing regimen provided well-tolerated, effective prophylaxis against venous thromboembolism in patients undergoing gastric bypass surgery.

Clinical outcomes related to interface type in patients with obstructive sleep apnea/hypopnea syndrome who are using continuous positive airway pressure.

STUDY OBJECTIVES: To evaluate the effect of interface on objective compliance, patient satisfaction, adverse effects, quality of life, and residual sleep-disordered breathing in patients with obstructive sleep apnea/hypopnea syndrome (OSAHS) using continuous positive airway pressure (CPAP). DESIGN: Randomized, cross-over. SETTING: Two suburban community-based hospital sleep laboratories. PATIENTS: Data were collected on 39 patients with OSAHS (mean age, 48.7 years), in whom CPAP was a novel treatment. INTERVENTIONS: Interventions were nasal pillows (Breeze; Mallinckrodt Corporation; Minneapolis, MN) and nasal mask (Contour; Respironics; Murrysville, PA). MEASUREMENTS AND RESULTS: Outcomes assessed at the completion of each 3-week treatment period were objective compliance, adverse effects, and satisfaction with CPAP (CPAP questionnaire), daytime sleepiness (Epworth sleepiness scale [ESS]), quality of life (Functional Outcomes of Sleep Questionnaire [FOSQ]), sleep diary, and residual sleep-disordered breathing (apnea-hypopnea index [AHI]). Patients were randomly assigned to use the nasal pillows or the nasal mask following laboratory titration and initiated on CPAP (pressure range, 5 to 14 cm H(2)O). The percentage of days utilized favored the nasal pillows (94.1% vs 85.7%; p = 0.02), but minutes of use per night did not differ (nasal pillows, 223 min; nasal mask, 288 min). ESS scores were lower and the FOSQ total scores were higher following CPAP treatment (p < 0.001), but no differential treatment effects were noted. Fewer adverse effects, less trouble getting to sleep and staying asleep, and less air leak were reported with nasal pillows (p < 0.04). The mean +/- SD pretreatment AHI (47.1 +/- 35.1/h) was significantly lower following treatment with CPAP for both types of interface (nasal pillows, 10.2 +/- 9.8/h; nasal mask, 7.0 +/- 7.7/h; p < 0.001). CONCLUSIONS: Nasal pillows are a well-tolerated and effective interface for OSAHS patients receiving CPAP at < or = 14 cm H(2)O. Use of nasal pillows was associated with fewer adverse effects and better sleep quality during the first 3 weeks of CPAP therapy. Further investigation is needed to determine whether interface type affects long-term CPAP use.

Comparison between automatic and fixed positive airway pressure therapy in the home.

We tested the hypothesis that continuous positive airway pressure (CPAP) use and outcomes can be improved by an autotitrating CPAP device in patients with obstructive sleep apnea-hypopnea syndrome (OSAHS) who require higher CPAP (10 cm H2O or more). In this multisite randomized single-blind cross-over study, 44 patients (mean age, 49 +/- 10 years) were randomized to 6 weeks at laboratory-determined fixed pressure and 6 weeks on autotitrating CPAP. Average nightly use was greater in automatic mode (306 versus 271 minutes, p = 0.005); median and 95th centile pressures in automatic mode were lower (p < 0.002). Automatic CPAP resulted in better SF-36 Vitality scores (65 +/- 20 versus 58 +/- 23, p < 0.05) and mental health scores (80 +/- 14 versus 75 +/- 18, p < 0.05), but no significant difference in Epworth score (p = 0.065). During automatic therapy, patients reported more restful sleep, better quality sleep, less discomfort from pressure, and less trouble getting to sleep for both the first week of therapy and for the averaged scores for Weeks 2-6 (all p values < 0.006). Patients who require higher fixed CPAP use autotitrating CPAP more and report greater benefit from this therapy.