Quantifying nanomolar levels of nitrite in biological samples by HPLC-Griess method: special reference to arterio-venous difference in vivo.

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Quantifying nanomolar levels of nitrite in biological samples by HPLC-Griess method: special reference to arterio-venous difference in vivo.

Tohoku J Exp Med. 2008 May;215(1):1-11

Authors: Ishibashi T, Miwa T, Shinkawa I, Nishizawa N, Nomura M, Yoshida J, Kawada T, Nishio M

Nitrite (NO(2)(-)) is assumed to play an important role in regulation of vascular tone as a reservoir of nitric oxide (NO). To examine its physiological contribution, however, a sensitive method is required for determination of the true level of NO(2)(-) in biological samples. To this end, practical consideration to avoid NO(2)(-) contamination through the quantification procedure is important. We present here a highly sensitive and accurate method for determining NO(2)(-) in plasma by improving the HPLC-Griess system with minimal NO(2)(-) contamination in the samples. The system achieved high sensitivity (detection limit of 2 nM and sensitivity to 1 nM) and complete separation of the NO(2)(-) signal peak by modifying the system setup and mobile phase. Using this method, we achieved acceptable quantification of low NO(2)(-) levels in plasma. Deproteinization by ultrafiltration and exposure to atmosphere before measurement were identified as the major sources of NO(2)(-) contamination during sample processing. We addressed these issues by the use of methanol for deproteinization and gas-tight caps. These countermeasures allowed us to detect small arterio-venous NO(2)(-) differences in rabbit plasma that may indicate kinetic difference of NO(2)(-) in a small number of samples (n = 6). This difference became prominent when NO(2)(-) or a NO releasing agent, NOR1, was intravenously applied. Our results indicate that application of a sensitive method with careful handling is important for accurate determination of NO(2)(-) and that our method is applicable for further examination of the kinetic features of NO(2)(-) in vivo.

PMID: 18509230 [PubMed - in process]

June 3, 2008 | Filed Under Nursing | Leave a Comment 

Factors Associated With Hospital Retention of RNs in the New York City Metropolitan Area: An Analysis of the 1996, 2000, and 2004 National Sample Survey of Registered Nurses.

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Factors Associated With Hospital Retention of RNs in the New York City Metropolitan Area: An Analysis of the 1996, 2000, and 2004 National Sample Survey of Registered Nurses.

Policy Polit Nurs Pract. 2008 May 28;

Authors: Rosenfeld P, Adams RE

The nursing shortage is well documented, and government estimates indicate that shortfalls will worsen in the future. As the largest employer of registered nurses (RNs), hospitals are the most seriously affected by shortages, as they compete with other employment settings for limited nursing resources. Recruitment remains the primary avenue for ensuring staffing levels, but retention is increasingly important as applicant pools shrink because of demographic and employment trends. Effective retention strategies must address the factors that contribute to exodus of RNs from hospitals, as well as isolating the factors that enable RNs to remain in hospital employment. This secondary analysis of the 1996, 2000, and 2004 National Sample Survey of Registered Nurses examines the demographic, employment, and educational factors associated with working in hospitals, having full-time status, and holding patient care positions. The findings suggest that hospitals must address nonwork issues to retain nursing personnel. Relevant policy issues are examined and strategies for effective retention are offered.

PMID: 18509198 [PubMed - as supplied by publisher]

June 3, 2008 | Filed Under Nursing | Leave a Comment 

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