Proteome alterations in human autopsy tissues in relation to time after death.

Protein expression is a primary area of interest for routine histological diagnostics and tissue-based research projects, but the limitations of its post-mortem applicability remain largely unclear. On the other hand, tissue specimens obtained during autopsies can provide unique insight into advanced disease states, especially in cancer research. Therefore, we aimed to identify the maximum post-mortem interval (PMI) which is still suitable for characterizing protein expression patterns, to explore organ-specific differences in protein degradation, and to investigate whether certain proteins follow specific degradation kinetics. Therefore, the proteome of human tissue samples obtained during routine autopsies of deceased patients with accurate PMI (6, 12, 18, 24, 48, 72, 96 h) and without specific diseases that significantly affect tissue preservation, from lungs, kidneys and livers, was analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). For the kidney and liver, significant protein degradation became apparent at 48 h. For the lung, the proteome composition was rather static for up to 48 h and substantial protein degradation was detected only at 72 h suggesting that degradation kinetics appear to be organ specific. More detailed analyses suggested that proteins with similar post-mortem kinetics are not primarily shared in their biological functions. The overrepresentation of protein families with analogous structural motifs in the kidney indicates that structural features may be a common factor in determining similar postmortem stability. Our study demonstrates that a longer post-mortem period may have a significant impact on proteome composition, but sampling within 24 h may be appropriate, as degradation is within acceptable limits even in organs with faster autolysis.

Polydipsia screening tool.

Polydipsia is a condition whereby individuals consume excessive amounts of liquids, which is common in patients with schizophrenia. A 17-item Polydipsia Screening Tool (PST; Copyright 2000 by Sheila Reynolds) was evaluated for psychometric properties. Five nurses and 70 psychiatric residents in a 92-bed nursing home comprised the samples. The interrater reliability (mean intraclass correlation coefficient) was 0.84. The average test-retest agreement was 92.4% with agreement ranging from 75% to 100%. Internal consistency of the tool was 0.79. Sensitivity and specificity were 80% and 68%, respectively. Additionally, validity of the PST was supported using a medical record history of polydipsia, low serum sodium, and low specific gravity.

Identifying at risk nursing home residents using a polydipsia screening tool.

Persons diagnosed with schizophrenia are considered at risk for polydipsia, a potentially life-threatening condition characterized by excessive consumption of fluids. This study examined the demographic and health-related characteristics of nursing home residents with psychiatric diagnoses (N = 70) who reside in a 92-bed facility. The prevalence of polydipsia and behavioral characteristics and symptoms as measured by a 17-item polydipsia screening tool also were described. Patients who screened positive for polydipsia (36%) exhibited behaviors that included incontinence, smoking, frequent voiding, and preference for fluid over food. A polydipsia screening program could minimize morbidity and mortality associated with this fairly prevalent condition.