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Biomedical subjects

D N Vieira

Publications and source records attributed to D N Vieira.

18 recordsLinked to original sources

Population distribution of six PCR-amplified loci in Madeira Archipelago (Portugal).

Frequency data of the short tandem repeat (STR) loci HUMTH01, HUMVWA31/A, HUMF13A1, HUMFES/FPS, D12S391 and HUMFIBRA/FGA were determined in blood stains obtained from a population of unrelated individuals from the Madeira Archipelago. The observed genotype distribution showed no significant deviation from the Hardy-Weinberg equilibrium and there was no evidence for association of alleles among the six loci. Population data showed a combined discrimination power of 0.9999998 and a chance of exclusion of 0.99597. The frequencies are similar to those of other compared caucasian populations but significant differences were found between the Madeira population and Japanese, Chinese, Greenland Eskimos and Quechua Amerindians. The six loci studied, together proved to be highly discriminating and valuable for forensic cases.

Blood Stains

Concealed homicidal strangulation by burning.

Compression of the neck, either with the hands or by a ligature, is not an uncommon method of homicide. Burning of the body to try to conceal the homicide may complicate the situation by making it difficult to interpret the findings. We hereby report two cases of homicidal ligature strangulation with extensive burning of the bodies. In both cases, external findings included the presence of a soft piece of fabric around the neck that, when removed, disclosed a portion of pale, unburned skin that vividly contrasted with surrounding areas. Osteocartilaginous lesions were present in only one case. Carboxyhemoglobin levels in both cases were very low, and the histopathologic examination of distal airways for soot particles was negative.

Aged

Population study of HUMTH01, HUMVWA31/A, HUMF13A1, and HUMFES/FPS systems in Azores.

The tetrameric short tandem repeat polymorphisms HUMTH01, HUMVWA31/A, HUMF13A1, and HUMFES/FPS were studied in blood stains obtained from a population of unrelated individuals from the Azores Archipelago (Portugal). Gene frequencies were determined and no deviation from the Hardy-Weinberg equilibrium was found. However, the allelic independence test between loci showed linkage disequilibrium between HUMVWA31/A and HUMFES/FPS. A combined discrimination power and chance of exclusion of, respectively, 0.9999 and 0.9534, reveal the high forensic interest of the four systems. No differences with other caucasoid populations were found, but comparison with some asiatic, eskimo, and amerindian populations showed significant statistical differences.

Amino Acid Sequence

Lipid peroxidation in lung tissue after chest trauma and correlation with the duration of the post-trauma survival period.

Blunt chest trauma is a frequently encountered cause of death in forensic pathology and one of the organs most likely to be affected are the lungs. Assuming that the victim survives the initial trauma, reperfusion processes take place, free radicals are formed and lipid peroxidation occurs. The aim of this study was to ascertain whether the length of the survival time is correlated with the extent of lipid peroxidation in the lung tissue following such ischaemia-reperfusion processes. A study of 470 samples taken from all five pulmonary lobes from 94 cadavers was carried out. Cases were allocated to different groups according to whether there was chest trauma and/or a known survival period. Lipid peroxidation was investigated by determining malondialdehyde (MDA) levels. The lowest mean level of peroxidation was found in control cases showing no evidence of chest trauma at autopsy and no apparent survival period. Our results suggest that the level of lipid peroxidation in lung tissue can be a reliable indicator of survival processes.

Adult

Distribution of biochemical markers in biologic fluids: application to the postmortem diagnosis of myocardial infarction.

We evaluated the usefulness of postmortem determination of biochemical markers and the ratio of their concentrations in pericardial fluid and serum to diagnose acute myocardial necrosis. One hundred cadavers from routine necropsies were studied. Cases were allocated in diagnostic groups according to the cause of death. Myoglobin and myosin heavy chain concentrations and creatine kinase MB isoenzymes (CK-MB) activities were measured in serum and pericardial fluid. Ratios of the concentrations obtained in these fluids were calculated. Hematoxylin and eosin (H&E) and acridine orange stains were used for microscopy studies. Pericardial fluid-serum ratios of the concentrations of biochemical markers were significantly different. The ratio of the concentrations of myosin is the best indicator of wide-spread muscle damage or cardiac necrosis.

Adolescent

Diagnostic ability of D-dimer in the establishment of the vitality of wounds.

The potential of skin measurements of D-dimer (DD), a specific derivative of crosslinked fibrin, for the diagnosis of the vital origin of wounds was investigated in 67 human vital skin wounds and homolateral control pieces of skin from 53 autopsies performed at the Institute of Legal Medicine of Coimbra (Portugal) during 1992. Our results demonstrate that DD levels for the incised vital skin wounds (n = 50) were much higher on average than their controls (P < 0.01) which were actually incised injuries produced postmortem at the autopsy. We did not find any statistical difference in average DD levels among the remaining injuries (seven abrasions and ten contusions) in comparison to their respective controls. DD may be used, with certain limitations, as a marker of the vitality of incised wounds. The authors believe this is the first time this marker has been applied in forensic pathology. It is an example of an easy and quick application technique, with the added advantage of low cost.

Autopsy

Usefulness of myosin in the postmortem diagnosis of myocardial damage.

In some situations the postmortem diagnosis of myocardial infarction is made difficult by the brief course of the fatal episode or by interferences caused by autolysis. In such cases, biochemical indices may provide a useful adjunct to morphological studies. Myosin is the main component of the contractile apparatus of muscle cells, so its determination may well be useful to evaluate myocardial injury. The purpose of the present study was to establish the diagnostic efficacy of postmortem myosin heavy chain determinations using monoclonal antibodies and to compare this data with structural findings used to diagnose acute myocardial ischaemia. We studied 105 cadavers with a mean age of 61.63 +/- 2.21 years. Cases were allocated to 1 of 7 diagnostic groups depending on the probable intensity of myocardial damage and cause of death. The highest serum and pericardial fluid values of myosin heavy chains were seen in subjects who showed morphological evidence of myocardial ischaemia. Mean pericardial fluid/serum ratios differed significantly between subjects with and without observable signs of heart damage.

Analysis of Variance

Biochemical assessment of acute myocardial ischaemia.

AIMS: To evaluate the efficacy of biochemical parameters in different fluids in the diagnosis of myocardial infarction of different causes, analysed after death. METHODS: The myoglobin concentration and total creatine kinase (CK) and creatine kinase MB isoenzyme (CK-MB) activities were measured in serum, pericardial fluid, and vitreous humour from seven diagnostic groups of cadavers classified according to the severity of myocardial ischaemia and cause of death. Lactate dehydrogenase (LDH) and myosin were measured only in serum and pericardial fluid, and cathepsin D only in pericardial fluid. Routine haematoxylin and eosin and acridine orange staining were used for microscopy studies of heart tissue. RESULTS: In pericardial fluid there were substantial differences between the different groups with respect to CK, CK-MB, and LDH activities and myosin concentrations. The highest values were found in cases with morphological evidence of myocardial ischaemia. CONCLUSIONS: Biochemical parameters, which reach the pericardial fluid via passive diffusion and ultrafiltration due to a pressure gradient, were thus detectable in this fluid earlier than in serum in cases with myocardial ischaemia. These biochemical parameters may be of use for ruling out myocardial ischaemia in those controversial cases in which reliable morphological findings are lacking.

Adolescent

Prostaglandin F2a (PGF2a): an inadequate marker of the vitality of wounds?

We have studied the viability of PGF2a as a vitality marker in skin wounds. Incised vital skin wounds and homolateral control pieces of skin were obtained from 20 autopsies performed at the Institute of Legal Medicine of Coimbra University (Portugal). We have also studied 10 fresh skin samples from the Department of Dermatology of the University Hospital (Granada). Our results show that PGF2a is not suitable for the diagnosis of the vitality of wounds because of its irregular behaviour.

Biomarkers

[Postmortem orbital hematomas].

Several cases of post mortem hematoma resulting from harvesting of the eye globes for transplantation, and susceptible of being misinterpreted as representing ante mortem trauma, are presented. Based on these cases the authors make a few considerations about the mechanisms of their production and technical procedures to avoid them.

Adult

Homicidal hanging.

We report a case of homicide by hanging of a 29-year-old woman that was committed by her husband, who nearly escaped from justice. We offer some reflections on the rarity of this method of mechanical asphyxia in cases of homicide, and on the difficulties in the diagnosis of the medico-legal etiology of these situations. We also offer a short review of similar cases in the medico-legal literature.

Adult

[Hepatic markers in a population of tavern customers].

We undertook this study to determine the prevalence of hepatic enzymes alterations in ambulant and healthy daily consumers of alcoholic beverages. In order to achieve this aim, a population of 107 regular customers from Coimbra's taverns was utilised. The percentage of results above the reference values was: Alk. Ph.-0%, AST/ALT--10.3%, T. Bil.--18.7%, ALT--37.4%, AST--44.9%, D. Bil.--52.3%, GGT--54.2%, GIDH--55.8%; seven individuals had normal levels of all hepatic markers, seventeen had 1 altered parameter, twenty two had 2, fourteen had 3, fifteen had 4, twenty had 5, eleven had 6, and one had 7. However, most of the alterations occur to levels close to normality. The correlation with the doses of alcohol is positive but low for all studied parameters, being statistically significant for some of them. The main conclusion of the present work is the demonstration that almost all tavern customers may already have disturbances of their hepatic biochemistry, though they look healthy, what represents an important and serious Public Health problem.

Adult

[Paraquat poisoning. Pulmonary lesions].

The preliminary results of a study of the pulmonary histopathological injuries observed in autopsy samples from six paraquat poisoning cases are presented. The pattern of the pulmonary injuries is discussed with regard to the survival time. Twenty-four hours after the ingestion, intense edema of the alveolar walls, congestion, capillary thrombosis and infiltrations of polynuclears in the septa were observed. Areas of ischemic necrosis were also noticed. Four days after the ingestion the histological changes remained. Six days after it was already observed the formation of hyaline membranes. After nine days the histological patterns changed, with thickness and septal fibrosis and residues of hyaline membranes.

Adult

[Accidental hanging during auto-erotic practices].

An unusual case of accidental hanging during autoerotic practices in a 25-year-old male student is described and the autoerotic asphyxia syndrome briefly discussed. The authors stressed the importance of a correct diagnostic of accidental death in these cases.

Accidents