Immunohistochemical detection of fibronectin and tenascin in incised human skin injuries

Immunohistochemical detection of molecules involved in inflammatory reaction can be useful for the diagnosis of vitality in skin wounds. We studied the expression of fibronectin (FN) and tenascin (TN) in 58 human skin wounds (48 vital and 10 postmortem). The age of vital injuries ranged from 3 min to 8 h and postmortem specimens were collected after a postinfliction interval of 15-180 min. One hundred thirty-seven formalin-fixed paraffin-embedded sections (mean: 2.3 sections per case) were stained with each of two monoclonal antibodies against FN and TN using the streptABC technique. A reticular staining for FN in wound edge and dermis was observed in 50% of vital specimens versus 0% in postmortem cases. Immunoreactivity was reduced in 10 autolysed cases. FN positivity exclusively at the injury margin was observed in 39.4% of vital wounds and 10% of postmortem cases. TN was negative in all specimens. Vital and postmortem hemorrhage areas showed positivity for FN and TN. Due to its low sensitivity, immunohistochemical analysis of FN is useful for determining vitality only in a minority of cases. Different factors in everyday practice, including autolysis and technical problems often produce false negative reactions with the result that FN cannot be regarded as a reliable parameter of vitality. Positive reactions (network staining) are more valuable than negativity but are not pathognomonic. Both vital and postmortem hemorrhages show an enhanced positivity for FN and TN, thus impeding the diagnosis.     

Pulmonary embolism: a rare cause of sudden infant death

Pulmonary embolism can be observed at any age, but it occurs very rarely in the infant. The authors report the case of a 12-month-old boy who suddenly died during clinical improvement of gastroenteritis associated with otitis. Autopsy showed signs of dehydration and acute left pulmonary embolism, which was the cause of death. Thrombosis of the inferior vena cava extending into renal veins was seen. In this case, plasma hyperosmolality caused by dehydration might have favored the formation of venous thromboses. The various risk factors of pulmonary embolism in the child are discussed, including genetic factors.     

The 2000-2001 GEP-ISFG Collaborative Exercise on mtDNA: assessing the cause of unsuccessful mtDNA PCR amplification of hair shaft samples

We report the results of Spanish and Portuguese working group (GEP) of International Society of Forensic Genetics (ISFG) Collaborative Exercise 2001-2002 on mitochondrial DNA (mtDNA) analysis. 64 laboratories from Spain, Portugal and several Latin-American countries participated in this quality control exercise. Five samples were sent to the participating laboratories, four blood stains (M1-M4) and a sample (M5) consisting of two hair shaft fragments. M4 was non-human (Felis catus) in origin; therefore, the capacity of the labs to identify the biological source of this sample was an integral part of the exercise. Some labs detected the non-human origin of M4 by carrying out immuno-diffussion techniques using antihuman serum, whereas others identified the specific animal origin by testing the sample against a set of animal antibodies or by means of the analysis of mtDNA regions (Cyt-b, 12S, and 16S genes). The results of the other three human blood stains (M1-M3) improved in relation to the last Collaborative Exercises but those related to hairs yielded a low rate of success which clearly contrasts with previous results. As a consequence of this, some labs performed additional analysis showing that the origin of this low efficiency was not the presence of inhibitors, but the low quantity of DNA present in these specific hair samples and the degradation.As a general conclusion the results emphasize the need of external proficiency testing as part of the accreditation procedure for the labs performing mtDNA analysis in forensic casework.     

Results of the GEP-ISFG collaborative study on the Y chromosome STRs GATA A10, GATA C4, GATA H4, DYS437, DYS438, DYS439, DYS460 and DYS461: population data

The Spanish and Portuguese ISFG Working Group (GEP-ISFG) carried out a collaborative exercise in order to asses the performance of two Y chromosome STR tetraplexes, which include the loci DYS461, GATA C4, DYS437 and DYS438 (GEPY I), and DYS460, GATA A10, GATA H4 and DYS439 (GEPY II). The groups that reported correct results in all the systems were also asked to analyse a population sample in order to evaluate the informative content of these STRs in different populations. A total of 1020 males out of 13 population samples from Argentina, Brazil, Costa Rica, Macao, Mozambique, Portugal and Spain were analysed for all the loci included in the present study. Haplotype and allele frequencies of these eight Y-STRs were estimated in all samples. The lowest haplotype diversity was found in the Lara (Argentina) population (95.44%) and the highest (99.90%) in Macao (China). Pairwise haplotype analysis showed the relative homogeneity of the Iberian origin samples, in accordance with what was previously found in the European populations for other Y-STR haplotypes (http://www.ystr.org). As expected, the four non-Caucasian samples, Macao (Chinese), Mozambique (Africans), Costa Rica (Africans) and Argentina (Lara, Amerindians), show highly significant Phist values in the pairwise comparisons with all the Caucasian samples.     

Frequency of bone lesions: an inadequate criterion for gunshot wound diagnosis in skeletal remains

A retrospective study was carried out on 130 fatalities due to gunshot wounds to determine whether the combined absence of bone damage and projectile in a skeleton is sufficient to eliminate a diagnosis of gunshot wound. Our findings showed that bone lesions were present in about 90% of the cases and were associated with intracorporeal projectile(s) in about 70% of the cases. The presence or absence of bone lesions seemed independent of the gun characteristics, the shot conditions, and the type of death. The cause of death was predominantly brain injury in cases with bone lesions whereas thoracic, abdominal, and peripheral vascular causes were more frequently encountered in cases without bone damage. We concluded that the combined absence of bone lesions and intracorporeal projectile (about 5% in our series) cannot exclude a diagnosis of death secondary to gunshot wounds.