Genetic profiling of a central Venezuelan population using 15 STR markers that may be of forensic importance

The AmpFlSTR Identifiler kit has recently been accepted for use in DNA databasing of forensic samples in the FBI's National DNA Index System. In the present study, we used this kit to analyze the allele distribution of 15 short tandem repeat markers (STR) in individuals living in Caracas city, Venezuela. The allele frequencies of two of these STR, D2S1338 and D19S433, have not previously been reported for this or any other Latin American population. The results indicate that for the population here studied, the 15 STR tested are useful markers for paternity testing and forensic casework.     

The analysis of illicit methaqualone containing preparations by gas chromatography-mass spectrometry for forensic purposes

A validated gas chromatographic-mass spectrometric method for quantitative analysis of methaqualone (MTQ) in illicit preparations is reported. The method proved to have a coefficient of variation of below 5%. Four batches of seized tablets, two pairs with similar imprints, were analyzed. It was found that the average MTQ concentration in all four batches of tablets differed significantly (p = 0.01) rendering it impossible to conclude that, on the basis of MTQ concentration alone, the batches with a similar logo originated from the same manufacturer or manufacturing batch. Conversely, it can be said that in this case, the four batches originated from either different clandestine laboratories or manufacturing batches.     

Adult Hirschsprung's disease diagnosed during forensic autopsy

We report a case of fatal Hirschsprung's disease (HD) discovered at autopsy. A 20-year-old man collapsed at home. Emergency medical personnel found him in cardiac arrest and all resuscitative efforts failed. He had a past history of chronic constipation since infancy. Forensic autopsy revealed a megacolon full of gas and stools. Microscopic examination showed absence of ganglion cells in a short segment of the rectum and enterocolitis in the left and transverse colon. HD is rarely described in adults. In many cases, patients complained of constipation since infancy but the affection remained misdiagnosed. The relative good tolerance of the disease is usually due to a short aganglionic bowel segment. Enterocolitis is a frequent and severe complication of HD in children but is rarely described in adults. This case suggests the importance of HD diagnosis in childhood in order to avoid fatal complications with forensic consequences.     

Instability of calcium channel antagonists during sample preparation for LC-MS-MS analysis of serum samples

1,4-Dihydropyridines calcium channel antagonists (1,4-DHP CCAs) are photolabile and the products of their photodecomposition have no pharmaceutical activity. In our previous work we have presented a screening procedure for eleven 1,4-DHPs in plasma by LC-MS-MS using multiple reaction motoring. The laboratory process includes preparation and storage of stock solutions, plasma storage, solid-phase extraction, reconstitution of extracts and storage time in an autosampler for LC-MS-MS analysis. Prior to validation of the analytical procedure, we have tested the stability of these compounds by exposure to light. Methanolic solutions have been exposed to laboratory and UV light and the stability of the compounds in plasma was tested by exposure of spiked plasma samples to laboratory light at room temperature. Stability during freeze-thaw cycles and stability during 2 month storage at -20 degrees C have been tested as well. Products of photodecomposition have been identified after forced degradation and the degree of degradation has been quantified using LC-UV-DAD and LC-MS-MS, respectively. A 96% degradation after only 2h has been observed when solutions of nifedipine or nisoldipine were exposed to laboratory light in clear glass vials. In plasma samples degradation was 25% in only 2h for both compounds. The main degradation product was produced by oxidation of the dihydropyridinic ring resulting in the pyridine analogue that has been described as the first metabolite in the metabolic pathway. Only minor degradation was found for the other tested compounds after 2h light exposure in methanolic solutions. Furthermore, lercanidipine and nicardipine were also degradated by esterhydrolysis. Several additional minor degradation products were found for the other tested 1,4-DHPs, however, some of them could not be identified. Preconditions for storage and handling of plasma samples prior to and during analysis for 1,4-DHP CCAs are suggested in order to avoid photodecomposition of the analytes.     

A Peruvian population study of eight Y-chromosome STR loci

We have analyzed the distribution of the allele frequencies and haplotypes at eight Y-chromosomal short tandem repeat (STR) loci (DYS437, DYS438, DYS439, DYS460, DYS461, GATA A10, GATA C4 and GATA H4) in a sample population of 87 unrelated individuals from Perú.     

A singular case of murder-suicide committed with a homemade firearm

The authors illustrate a peculiar case of murder-suicide committed with a homemade firearm loaded with 12-gauge cartridges (buckshot). The structure and function of this handcrafted firearm were simple but effective: an iron tube did duty as a barrel in this primitive firearm. The cartridges (modified by winding sticky tape around the external surface of the base) were inserted down one end of the tube (serving as the breech). A second iron tube with a larger diameter (so as to be able to run over each of the preloaded barrels) and with a jutting, cone-shaped metal wedge soldered to the base, was used as a rudimental firing pin. After loading the "barrel" with the modified cartridge, the gunman would ram the "firing pin" tube violently down to fire the shot. Autopsy of the woman's body showed the presence of 3 gunshot wounds caused by buckshot, while the man had a single buckshot wound in the head. Subsequent ballistic investigations enabled reconstruction of the event (typical of murder-suicide) and the functioning of the firearm, demonstrating its lethal nature, remarkably easy handling, and simplicity of production.     

Postmortem vitreous humor beta-hydroxybutyrate: its utility for the postmortem interpretation of diabetes mellitus

Ketoacidotic coma is one of the most serious complications arising from diabetes mellitus, especially type I, and may be the cause of sudden death especially in diabetes type I. Since beta-hydroxybutyrate (beta-OHB) serum concentrations might provide more information on the severity of ketoacidosis, the aim of this study was to evaluate the concentrations of beta-OHB in vitreous humor and its correlation with other biochemical parameters during postmortem examination. We intended to ascertain the sensitivity and the specificity of these markers for diagnosing diabetes mellitus and the presence of ketoacidosis. This study involved 453 cadavers with a mean age of 57.6 years (S.D. 20.7) and a mean postmortem interval of 17.8 h (S.D. 9.6, range 2-61 h). Cases were assigned to two diagnostic groups according to the antemortem diagnosis of diabetes mellitus, based on the patients' medical records. In vitreous humor statistically significant differences were found in biochemical marker concentrations between the two diagnostic groups, the highest values being obtained in the group of subjects with a previous diagnosis of diabetes mellitus. The measurement of beta-OHB in vitreous humor may be a useful alternative to using blood during postmortem analysis. The presence of high levels of beta-OHB may help interpret the cause of death in diabetics when the autopsy result is negative.