Biomedical subjects
Publications and source records attributed to H van de Voorde.
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.
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.
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.
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 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.
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.
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.
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.
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.
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.
The concept of avoidable mortality leads to an attempt at using specific mortality rates as output measures of health services. The analysis covered 43 Belgian districts between the years 1974 and 1978. Two Belgian areas were compared along a dimension defined by two axes of a correspondence factor analysis: Flanders which is associated with low SMR of avoidable mortality and Wallonia which has high rates. The persistence of high mortality in Wallonia was confirmed. Factorial scores for each district were used as indexes for geographical heterogeneity. Variations in these indices, including patient consultation rates and technical medical procedures, remained even after adjustment for socio-economic differences.
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.
The calls to a telephone counselling service at Louvain, during a 21-month period, from one telephone zone were analysed. Data were studied in relation to the type of weather, which was recorded every day. Calls made by women about health and interpersonal problems showed a relationship to the weather, while calls apparently motivated by masturbation intentions from male callers increased when the weather improved.
In order to standardize antifungal disinfectant testing using Candida albicans as a test organism, the morphology of four type strains of C. albicans DSM 1836, ATCC 10231, CNCM 1180-79 and CBS 562, grown on sixteen different media was determined. The incubation was carried out at 28 degrees C and 37 degrees C. The yeast phase was obtained predominantly on TSA medium with all strains. Mixed phases, i. e. true mycelium and yeast cells, were easily obtained in TSB in shaking flasks for three type strains but not for CBS 562. True mycelium was formed on corn meal media (CMA) for all strains, but the growth was very poor. The morphology of the growth was determined more by the type of strain than by the nutritive medium. Therefore C. albicans ATCC 10231 grown on either TSA or CMA was used as a test organism. Its resistance was determined towards four disinfectant standards: benzalkonium chloride, mercuric chloride, phenol and o-phenylphenol. No difference in sensitivity was found for the former disinfectant, but yeast cells grown on TSA were more resistant than C. albicans cultures on CMA in case of mercuric chloride, phenol and o-phenylphenol.
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Microbiologic analysis of different soil samples was undertaken to assess the value of this method for forensic purposes. Three groups of micro-organisms were isolated on selective media: bacteria, fungi, and actinomycetes. Comparison of the morphology of the colonies led to the conclusion of non identity of the soil samples under examination. The method was applied to soil traces on articles of clothing, trousers, shoes, and stockings. It was found that the soil did not originate from the suspected scene of a crime. Examination of the microbiologic soil composition does not provide an absolute certainty of identity, but it is highly reliable.
In order to find out whether more than one test organism is needed for the determination of the activity of disinfectants towards mycelium-forming fungi and yeasts, eight different species of fungi and one yeast-like fungus were submitted to seven different disinfectants in varying concentrations. As Candida albicans was found to be the most resistant, the authors propose that only Candida albicans should be used.
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