title: Analysis of immunohistochemical expression of inducible nitric oxide synthase for the evaluation of agonal time in forensic medicine.
abstract: Although establishing agony is crucial in forensic practice, the identification of specific signs indicative of a detailed duration of agony is however not of immediate execution. Nitric oxide (NO) is the most important messenger molecule in the modulation of vascular tone and it is produced during stress conditions by inducible nitric oxide synthase (iNOS), as occurs during agony. The aim of this study was to investigate the relationship between immunohistochemical expression of iNOS, and agonal time (T), defined as the interval between the onset of a hypoxic-ischemic injury and the death. INOS expression was evaluated by measuring the average of signal intensity (SI) from cytoplasm of 300 smooth muscle cells of sample of renal artery, performed by ImageJ software: high values of SI correspond to a low enzyme expression and vice versa. We aimed also to check if gender, age, type of death (violent or natural death), post mortem interval, and storage in cold chamber influenced SI. We assessed 50 autopsied cases, of which 28 violent and 22 natural deaths, with a well-known T in a range between 1 and 631 min. Statistical analysis was performed to estimate the relationship between SI and the other variables. Results pointed out that only SI is related to T, and since data showed a bi-phase relationship between T and SI, we used a piecewise regression method for estimation of T as function of SI. The transition from the first to the second phase takes place at SI = 117.5 which corresponds to a T of 29.5 min. In conclusion, the study demonstrates that iNOS is a good marker for estimating T and the final regression model can be used in many forensic activities.
authors.affiliation: Department of Biomedical Sciences and Public Health, Section of Legal Medicine, Faculty of Medicine, Polytechnic University of Marche, Torrette di Ancona, 60020, Italy.|Institute of Legal Medicine, Department of Law, University of Macerata, Macerata, 62100, Italy.
authors.forename: R
authors.initials: R
authors.lastname: Scendoni
authors.affiliation: Center of Epidemiology, Biostatistics and Medical Information Technology, Department of Biomedical Sciences and Public Health, Polytechnic University of Marche, Torrette di Ancona, 60020, Italy.
authors.forename: L
authors.initials: L
authors.lastname: Ferrante
authors.affiliation: Department of Biomedical Sciences and Public Health, Section of Pathological Anatomy, Polytechnic University of Marche, Torrette di Ancona, 60020, Italy.
authors.forename: D
authors.initials: D
authors.lastname: Stramazzotti
authors.affiliation: Department of Biomedical Sciences and Public Health, Section of Legal Medicine, Faculty of Medicine, Polytechnic University of Marche, Torrette di Ancona, 60020, Italy. a.tagliabracci@univpm.it.
authors.forename: A
authors.initials: A
authors.lastname: Tagliabracci
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003593:Cytoplasm / Q000378:metabolism*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007150:Immunohistochemistry; D008297:Male; D008853:Microscopy; D008875:Middle Aged; D032389:Myocytes, Smooth Muscle / Q000378:metabolism*; D019001:Nitric Oxide Synthase / Q000378:metabolism*; D011180:Postmortem Changes; D012044:Regression Analysis; D055815:Young Adult
chemical_list: D019001:Nitric Oxide Synthase
keywords: Agonal time; Inducible nitric oxide synthase; Regression model; Time of death; Vascular smooth muscle cells