The effects of sucrose on stability of human brain natriuretic peptide [hBNP (1–32)] and human parathyroid hormone [hPTH (1–34)]

Abstract: Although the effect of sucrose on the physical stability of proteins has been well documented, its impact on their chemical stability is largely unknown. The aim of this study was to investigate the potential effects of sucrose on the structural conformation of human brain natriuretic peptide [hBNP (1–32)] and the synthetic human parathyroid hormone [hPTH (1–34)], and link these effects to chemical degradation pathways of these peptides. The stability of hBNP (1–32) and hPTH (1–34) was studied at pH 5.5. Aggregation was monitored using size exclusion high‐performance liquid chromatography (SE‐HPLC), whereas oxidation and deamidation products were measured by reversed phase (RP) HPLC. Fourier transform infrared (FT‐IR) spectroscopy was used to study the peptides’ conformation. Sucrose retarded aggregation, deamidation, and oxidation of hBNP (1–32) and hPTH (1–34), with a maximum effect at relatively high concentrations (as much as 1 m ). FT‐IR spectroscopy indicated that sucrose maintained the native conformation of hBNP (1–32) and induced small conformation changes in the hPTH (1–34) structure. Sucrose enhanced the stability of hBNP (1–32) and hPTH (1–34) in liquid formulations. The stabilizing effect of sucrose was due to a large extent to retardation of oxidation and deamidation of hBNP (1–32) and hPTH (1–34).     

Evaluation of fresh and cryopreserved hepatocytes as in vitro drug metabolism tools for the prediction of metabolic clearance.

The intrinsic clearances (CLint) of 50 neutral and basic marketed drugs were determined in fresh human hepatocytes and the data used to predict human in vivo hepatic metabolic clearance (CLmet). A statistically significant correlation between scaled CLmet and actual CLmet was observed (r2 = 0.48, p < 0.05), and for 73% of the drugs studied, scaled clearances were within 2-fold of the actual clearance. These data have shown that CLint data generated in human hepatocytes can be used to provide estimates of human hepatic CLmet for both phase I and phase II processes. In addition, the utility of commercial and in-house cryopreserved hepatocytes was assessed by comparing with data derived from fresh cells. A set of 14 drugs metabolized by the major human cytochromes P450 (P450s) (CYP1A2, 2C9, 2C19, 2D6, and 3A4) and uridine diphosphate glucuronosyltransferases (UGT1A1, 1A4, 1A9, and 2B7) have been used to characterize the activity of freshly isolated and cryopreserved human and dog hepatocytes. The cryopreserved human and dog cells retained on average 94% and 81%, respectively, of the CLint determined in fresh cells. Cryopreserved hepatocytes retain their full activity for more than 1 year in liquid N2 and are thus a flexible resource of hepatocytes for in vitro assays. In summary, this laboratory has successfully cryopreserved human and dog hepatocytes as assessed by the turnover of prototypic P450 and UGT substrates, and both fresh and cryopreserved human hepatocytes may be used for the prediction of human hepatic CLmet.     

Retrospective analysis of physical therapy utilization by the specificity of the diagnosis and order written on the referral

Background: Arguments against reimbursement for direct access to physical therapy (PT) are that a physician examination is necessary to diagnose and that there is a potential for increased cost. Objective: To determine what percentage of PT referrals had a specific diagnosis and treatment orders. Additionally, specific and non-specific diagnoses and treatment orders were compared in regards to PT units billed, average visits per referral, and average cost per referral. Methods: The charts of 1,000 patients treated in outpatient PT underwent a retrospective chart review. Interferential statistics were used to determine if there was a statistically significant difference between specific and non-specific diagnoses and treatment orders in regard to PT units billed, average visits per referral, and average cost per referral. Results: Twenty-nine percent of all referring diagnoses were non-specific in nature and 58% contained treatment orders that were non-specific. Charts with a specific diagnosis had a statistically significant higher utilization as compared to non-specific diagnoses (p ≤ 0.001). Patients with a specific treatment order also displayed a statistically significant larger average in billed units, average visits per referral, and average reimbursement per referral than those without a specific treatment order (p ≤ 0.0001). Conclusion: Our findings suggest that a physician diagnosis and referral may not be required to direct care for patients seeking PT services. Third-party payers that require a physician referral for PT services may be delaying access to healthcare and increasing costs.     

Validating a Hazardous Drinking Index in a Sample of Sexual Minority Women: Reliability,Validity, and Predictive Accuracy

Background: Although sexual minority women (SMW) are at increased risk of hazardous drinking (HD), efforts to validate HD measures have yet to focus on this population. Objectives: Validation of a 13-item Hazardous Drinking Index (HDI) in a large sample of SMW. Methods: Data were from 700 adult SMW (age 18-82) enrolled in the Chicago Health and Life Experiences of Women study. Criterion measures included counts of depressive symptoms and post-traumatic stress disorder (PTSD) symptoms, average daily and 30-day ethanol consumption, risky sexual behavior, and Diagnostic and Statistical Manual (DSM-IV) measures of alcohol abuse/dependence. Analyses included assessment of internal consistency, construction of receiver operating characteristic (ROC) curves to predict alcohol abuse/dependence, and correlations between HDI and criterion measures. We compared the psychometric properties (diagnostic accuracy and correlates of hazardous drinking) of the HDI to the commonly used CAGE instrument. Results: KR-20 reliability for the HDI was 0.80, compared to 0.74 for the CAGE. Predictive accuracy, as measured by the area under the receiver operating characteristic curve for alcohol abuse/dependence, was HDI: 0.89; CAGE: 0.84. The HDI evidenced the best predictive efficacy and tradeoff between sensitivity and specificity. Results supported the concurrent validity of the HDI measure. Conclusions: The Hazardous Drinking Index is a reliable and valid measure of hazardous drinking for sexual minority women.