Bayesian evaluation of the modified zinc test and the acid phosphatase spot test for forensic semen investigation.

The modified zinc test is evaluated as a screening instrument in forensic semen identification using the classical acid phosphatase test as a "gold standard" reference. Both tests were applied to vaginal swabs taken from women (n = 456) at varying time periods after sexual intercourse and the corresponding sensitivity and specificity were calculated for both tests separately and for their parallel and serial combination strategies, with the microscopical visualization of sperm as end criterion. The results were submitted to Bayesian calculations and a model was obtained, giving the posterior probabilities of finding or not finding sperm in a microscopical preparate for any possible prior probability. For the largest part of the theoretical sperm prevalence range, negative predictions were more informative than positive ones. With the prior probability of finding spermatozoa set at P = 0.5 (Bayes' postulate of neutral prior probability), the model was applied to a set of 192 pieces of evidentiary material from alleged sexual assaults.

[Predictive value of anthropometric parameters for birth weight]. / Valeur prédictive des déterminants anthropométriques du poids à la naissance.

A random series of 1,000 parturients in 2 maternity wards in Kinshasa in 1992 were studied. Several parameters affecting birthweight were measured. The predictive value of the Quetelet index, determined by Spearman correlation, was greater than the predictive value of skin folds, brachial circumference, adipose and muscular surfaces or fat mass and was slightly better than lean mass. Anthropometric measurements have certain inconvenience and other factors affect birthweight. These results suggest that the Quetelet index is a sufficiently precise tool for evaluating nutritional state. In addition, its use would allow more time for patient counselling. The longer doctor-patient dialogue could have an effect on prevention in the area of psycho-social stress. This latter factor, combined with the cumulated stress score, was found to be one of the 3 main factors in multiple linear regression evaluation of birthweights reported here.

Interference of body products, food and products from daily life with the modified zinc test and the acid phosphatase test.

The modified qualitative zinc test and the qualitative acid phosphatase test were applied to a total of 1774 semen-free stains made from human body products (n = 575), food products (n = 801), beverages (n = 146), water (n = 120) and other products from daily life (n = 132), in order to assess the degree of interference of these products with the preliminary screening for semen. The zinc test gave positive results in, respectively, 2.4, 3.1, 1.4, 14.1 and 23.5% of the samples, whereas the acid phosphatase test was positive in 3, 3.3, 0, 1.7 and 0% of the samples. Given the large number of positive test results found for products which eventually may be present in stains from alleged sexual assaults, it is concluded that positive screening test results should be interpreted with great caution.

Reckless behaviour related to the use of 3,4-methylenedioxymethamphetamine (ecstasy): apropos of a fatal accident during car-surfing.

A 26-year-old man died from severe brain contusion after falling from a moving car during an attempt at car-surfing. Toxicological urine screening was positive for amphetamines, the blood analysis revealed a MDMA level of 0.63 mg/l and a blood alcohol concentration of 1.23 g/l. The case is another example of the bizarre and reckless behaviour which may result from the euphorogenic activity of ecstasy and the circumstances in which it is commonly used.

On the influence of data source in aggregated data studies: a comparative study of suicide information based on death certificates and judicial files.

STUDY OBJECTIVE: The aim was to assess the differences in suicide data obtained from different database sources. DESIGN: Death certificate based data on suicidal deaths were compared with the information obtained from the non-natural death investigation files at the Public Prosecutor's Office. SETTING: The study was confined to the time period of 1981-1984 and to the residents of the district of Leuven (Belgium) who died in the district. MAIN RESULTS: Differences were found in the number of suicidal deaths reported as well as in the demographic variables, the distribution of suicide methods, and the place of death. Sixty percent of the records in both databases could be matched for all variables studied (age, gender, civil state, place of death, and suicide method), and another 10% if only place of death was allowed to differ. For 4.5% of the cases in the judicial files and for 8% of the records in the official statistics database no corresponding record from the other data source could be found. Based on simple probability statistics [P(missing record)+P(different information[present)] the possible minimum global information bias could be estimated to range from 7 to 42%. CONCLUSIONS: Different epidemiological pictures of suicide mortality may result from studying different data sources.

A more sensitive modification of the zinc test for seminal traces suitable for stable test paper strips.

A more sensitive modification of the zinc test for semen has been developed, which can be used either as a solution or incorporated into test papers. The latter retain their sensitivity for at least 3 months.

Evaluation of the modified zinc test and the acid phosphatase test as preliminary screening methods in sexual assault case material.

The modified zinc test and a commercially available acid phosphatase test were compared as to their screening parameters according to the microscopical finding of spermatozoa in cases of alleged sexual assault. The study involved 65 pieces of evidence material. It was found that the modified zinc test has a higher sensitivity and higher predictive values than the acid phosphatase test. However, when both tests are combined in parallel, the sensitivity and the negative predictive value could be raised to 99%. This finding suggests that a negative result obtained from the parallel combination of the modified zinc test and the acid phosphatase test predicts very well that no spermatozoa will be found at microscopical examination. Since the latter technique is the only one to give absolute proof of the seminal origin of stains or traces, the parallel combination of the zinc test and the acid phosphatase test might be useful in sorting out these cases or materials that deserve further investigation by more elaborate techniques.

Bloodgroup simulating activity in aerobic gram-negative oral bacteria cultured from fresh corpses.

The gram-negative aerobic oral bacterial flora of 100 consecutive corpses was isolated. After the identification and culturing of the isolated organisms, blood grouping was performed by the haemagglutination inhibition technique on dried culture smears, the dried culture medium and a dried ethanol extract of the bacteria. Forty-seven of the samples showed a gram-negative aerobic bacterial growth, giving 58 microorganisms of 14 different species. Positive blood grouping results were found in two of them (Escherichia coli and Serratia marcescens), both of type B. It is concluded that occasional mistyping of blood groups on saliva and oral material may be caused by the oral gram-negative aerobic flora, especially if the specimens are contaminated or putrefying.

ABO bloodgrouping on tooth material.

The ABO bloodgroup was determined on the pulp, dentin and enamel of 35 teeth using the adsorption-elution technique. A bloodstained compress from the extraction wound was used as the reference sample. Twenty teeth were examined within 6 weeks after extraction and fifteen teeth were examined 6-10 months after extraction. It was found, that bloodgrouping on pulp gives fairly good results, whereas the possibilities for correct bloodgrouping seem to be limited for dentin and debatable for enamel. Similar results were found in both groups of teeth.

The zinc test as an alternative for acid phosphatase spot tests in the primary identification of seminal traces.

The value of the acid phosphatase spot test in the primary visualization and identification of seminal traces is hampered by the sensitiveness of the enzyme to biodegradation. An alternative spot test is proposed, based on the high concentration of the more stable zinc metal in seminal plasma. The proposed zinc spot test is simple and suitable for on site investigation. Although the sensitivity in fresh stains is lower than that of the acid phosphatase spot test, this is largely compensated by the lower sensitiveness to biodegradation. The specificity for semen is higher than that of the acid phosphatase spot test. In vaginal swabs it was nevertheless seen, that samples should be taken within 24 h after alleged sexual assault to give reliable results.

Comparative study of the sensitivity and specificity of the zinc and acid phosphatase spot tests for the detection of seminal stains.

The sensitivity and specificity of a zinc spot test for the detection of semen were compared with those of an acid phosphatase detection method. As screening techniques both tests were found to be very sensitive, but the zinc test was more specific and was more reliable in older and especially in deteriorated specimens. It is concluded that the zinc spot test deserves at least the same place as the acid phosphatase test in the primary investigation of suspected semen stains and might well be the test of choice in older and poorly preserved stains.

Availability of psychotropic drugs and suicidal self-poisoning mortality in Belgium from 1971-1984.

Trends in completed suicide by solid or liquid substances in Belgium were investigated for the period 1971-1984 in relation with data about sales of psychotropic drugs. Mortality rose sharply between 1973 and 1980 (from 21.1 per million population of 15 years and older to 52.2 in males and from 26.7 to 61.7 in females) and decreased slightly thereafter. No apparent coincidence with the availability of psychotropic drugs was found, and the increasing risk of suicidal persons dying at home suggested an increase in the severity of the attempts until 1980. However, incidence changes could also have affected these trends. The evolution in accidental and in suicidal hospital rates suggested that emergency care had improved. Although barbiturate sales decreased continuously (from 46.7 packages per year per 100 population in 1974 to 28.5 in 1984), these drugs still account for a high proportion of fatal self-poisonings (23%) in Belgium. Possible shortcomings that could affect the validity of our findings are discussed.

Recent trends in methods of suicide.

Trends in completed suicide by method were analysed for Belgium between 1968-1972 and 1978-1981, using the information reported on death certificates. Around 1980, hanging was the most preferred method of suicide in both sexes, followed by firearms in males and poisoning by solid and liquid substances in females. Between 1970 and 1980, rates for all but one method (domestic gas) increased. The largest changes among men were seen for firearms and for poisoning, accounting respectively for 43% and 33% of the overall increase. For women, 48% of the rise was attributable to poisoning and 24% to drowning. The choice of method was seen to be influenced by age: hanging and drowning were the preferred methods for older people, whereas poisoning was the most popular among younger adults. The male-female ratio decreased for firearms and was reversed for poisoning and drowning. These findings are compared with trends in other industrialized countries, and the possibilities for suicide prevention by reducing the firearms and poisoning rates are discussed.

The role of intestinal bacterial heat production in confounding postmortem temperature measurements.

To assess the influence of anaerobic bacterial heat production in human stools as a confounding factor in postmortem rectal temperature measurements, in vitro experiments were carried out with human stools incubated at 37 degrees C for 6 h and at decreasing temperatures simulating a postmortem body cooling. Although a statistical significant heat production was observed, it was not relevant enough to explain a postmortem temperature plateau or a substantial rise in the postmortem body temperature. The experiments suggest that stools merely reflect the environmental thermal changes rather than producing bias and confounding by a bacterial heat production.

Fatality management in mass casualty incidents.

Medical involvement in mass casualty incidents requires proper planning and preparedness. In disaster situations, legal aspects concerning the dead add to the general problem of a lack of time, place and resources to maintain routine working conditions, and demand authority and competence. The aspects of planning the recovery of the dead, transportation and morgue facilities, establishment of cause of death, identification, and the final disposition of the dead are discussed. The implementation of forensic mass fatality teams is felt to be the right answer for a better planning and coordination.

[Relative risk areas in the Louvain region. An ordinal geographical analysis of the health status and the distribution of health care]. / Relatieve risicogebieden in het arrondissement Leuven. Een ordinale geografische analyse van de gezondheidstoestand en de spreiding van de gezondheidszorg.

The analysis of the absolute figures of 21 socio-economic, hygienic and demographic indicators for the 30 communes of the district of Leuven did not show significant differences. A fourfold ordinal analysis, however, revealed a systematic pattern of differences for wealth, hygienic amenities, migration, birth rate and SMR. Six types of communes with two relative risk areas were described: cities and city-like communes, residential areas, rural villages with high emigration rates, poor economic areas, and transition areas between rural villages and cities and between wealthy and poor economic areas. The same pattern was found, though to a lesser degree, in the distribution of the facilities for health care and social welfare. The more wealthy communes were very well provided by these services, while the relative risk areas were overlooked.

Epidemiological aspects of suicide among the young in selected European countries.

Trends in reported suicide rates were analysed for the ages 5-24 years in 21 selected European countries in 1970-74 and 1980-84. In children the precision of the rates was found to be low though there appeared to be a trend to increased suicide in boys. In adolescent and young adult males, however, there was a definite increase in suicide over the period studied, and this was much more marked than in females, in whom the rates had declined in eight countries. The Belgian situation was investigated in detail. Increases were most pronounced in 20-24 year-old males. Around 1981, about half of youth suicides were committed by firearms and medicaments, and these methods showed the largest increases in risk. The estimated under-reporting error diminished with increasing age and over the past ten years. It was larger in females, but did not bias the trends substantially. On the aggregated level, youth suicide was found most strongly associated with indicators of anomie and social isolation. The relevance of these findings in the search for determinants and for preventive strategies is discussed.

The geographical pattern of methods of suicide in Belgium: implications for prevention.

The geographical variation of reported suicide among the 43 Belgian districts was analysed for each method of suicide in both sexes and in two time periods: 1968-72 and 1978-81. Different descriptive methods were used to assess the patterns and changes in method-specific indirectly standardized death rates. It appeared that the overall suicide pattern was not always a good reflection of the method-specific patterns. Moreover, these seemed consistent in time and between sexes. Two important methods, which could be partially influenced, showed a remarkable concentration in some southern districts: suicidal poisoning by solid and liquid substances (in both sexes) and the use of firearms (in males). Drowning was much more concentrated in the West of the country and jumping was especially frequent in Brussels. Possible explanations and the relevance of these findings for prevention are discussed.

In vitro changes in human spermatozoa exposed to gastric juice: laboratory findings as a support for forensic practice.

Samples of complete human semen were incubated in gastric juice for different time periods at 37 degrees C, and by simulating the post-mortem temperature decrease of the human body. The changes in the spermatozoa were similar in both experiments. Short incubation specimens were examined directly with interference contrast microscopy and showed an almost immediate immobilization of spermatozoa when they were brought in contact with gastric juice. Specimens with longer incubation periods were stained with alcalic fuchsine and examined by immersion microscopy. There was a morphologically stable plateau for the heads of the spermatozoa for up to 6 h of incubation. The tails disappeared progressively in the first 45 min. After more than 6 h of incubation a progressive swelling and lysis of the heads was observed. Spermatozoa could be recognized for up to 7 days of incubation.

Birth cohort analysis of suicide mortality in Belgium 1954-1981 by a graphic and a quantitative method.

The effect of birth cohort upon the recent increase in Belgian suicide trends was analyzed by two techniques: a graphic display and an Age-Period-Cohort (APC) modelling procedure. Both suggest an analogous pattern: suicide mortality steadily increased within successive male cohorts born after 1920 and within female cohorts born even before 1900. Between 1970 and 1980, period related factors seem to have operated independently. Every technique of cohort analysis however has important interpretational limitations because of the variable interplay between age period and cohort factors. As a consequence, explanations remain very tentative, Notwithstanding its rather poor etiological power in suicide epidemiology, cohort analysis is very useful in the more accurate description and prediction of suicide trends.