Domestic and personal accidents. Prevention in the absence of professional supervision

This paper provides a review of a selection of recent papers, most of which derive from presentations given at the 4th World Conference on Injury Prevention and Control or the 6th International Conference on Product Safety Research, both of which took place in Amsterdam in May 1998. What all the accidents studied in these papers have in common is the absence of professional supervision. Everyone immediately involved in the incident--whether as injured party, unintended cause or informal supervisor is an 'amateur'. It is proposed that the term 'domestic and personal accidents' should be used to describe this group of accidents, the study of which has been neglected in comparison to transport and occupational injuries. It is argued that domestic and personal activities are more heterogeneous than ones with an element of professional supervision and are therefore more difficult to prevent. Nevertheless examples are given of where 'horizontal' approaches to analysis and prevention of these accidents have proved possible.     

Heat inactivation of hepatitis A virus in dairy foods

Experiments were performed to determine the thermal resistance of hepatitis A virus (HAV) in three types of dairy products containing increased amounts of fat content (skim milk, homogenized milk; 3.5% MFG, and table cream; 18% MFG). HAV-inoculated dairy products were introduced into custom-made U-shaped microcapillary tubes that in turn were simultaneously immersed in a waterbath, using custom-made floating boats and a carrying platform. Following exposure to the desired time and temperature combinations, the contents of each of the tubes was retrieved and was tested by plaque assay to determine the reduction in virus titer. Our data indicated that < 0.5 min at 85 degrees C was sufficient to cause a 5-log reduction in HAV titer in all three dairy products, whereas at 80 degrees C, < or = 0.68 min (for skim and homogenized milk), and 1.24 min (for cream) were needed to cause a similar log reduction. Using a nonlinear two-phase negative exponential model (two-compartment model) to analyze the data, it was found that at temperatures of 65, 67, 69, 71, and 75 degrees C, significantly (P < 0.05) higher exposure times were needed to achieve a 1-log reduction in virus titer in cream, as compared to skim and homogenized milk. For example, at 71 degrees C, a significantly (P < 0.05) higher exposure time of 0.52 min (for cream) was needed as compared to < or = 0.18 min (for skim and homogenized milk) to achieve a 1-log reduction in virus titer. A similar trend of inactivation was observed at 73 and 75 degrees C where significantly (P < 0.05) higher exposure times of 0.29 to 0.36 min for cream were needed to cause a 1-log reduction in HAV in cream, as compared to < or = 0.17 min for skim and homogenized milk. This study has provided information on the heat resistance of HAV in skim milk, homogenized milk, and table cream and demonstrated that an increase in fat content appears to play a protective role and contributes to the heat stability of HAV.     

In situ, High-Resolution Measurement of Dissolved Sulfide Using Diffusive Gradients in Thin Films with Computer-Imaging Densitometry

The technique of diffusive gradients in thin films (DGT) has been developed for the measurement of dissolved sulfide. Sulfide species from the sampled waters diffuse through a polyacrylamide hydrogel and then react with pale yellow AgI((s)), incorporated at the surface of a second gel, to form black Ag(2)S((s)). The accumulated sulfide can be measured with a conventional purge-and-trap method followed by colorimetry (methylene blue). This enables the dissolved-sulfide concentration to be calculated under suitable conditions. Alternatively, the color change in the accumulating gel can be used to measure sulfide. A conventional flat-bed scanner, allied to imaging software, provided a densitometric measurement that was quantitatively related to the amount of sulfide accumulated. DGT measurements on synthetic solutions accurately determined the sulfide concentration (95% recovery), thereby confirming the unobstructed diffusion of HS(-) through the gel. The accumulated mass was inversely proportional to the diffusion-layer thickness as theoretically predicted. With the selected geometry, the limit of detection of the densitometric procedure for a 24-h deployment was 0.13 μmol L(-)(1), and the maximum concentration measurable was 60 μmol L(-)(1). When used in anoxic lacustrine waters, DGT provided sensible concentrations. It was also used to measure depth profiles at submillimeter resolution in estuarine surface sediments.     

The dual function of the proliferating cell nuclear antigen (PCNA) in the response of human cells to UV damages

An auxiliary protein of DNA polymerases delta and epsilon, the proliferating cell nuclear antigen (PCNA), is necessary for efficient DNA replication in vivo and in vitro, and also for the repair synthesis in vitro, but its role in the excision repair of genome in vivo is not exactly established. In S-phase of unirradiated cells, PCNA is tightly bound to focal centers of DNA replication and is not removed by treatment with detergent Triton X-100, but is completely extracted from non-S-phase cells by the indicated detergent. It was shown earlier that after UV-irradiation PCNA could not be removed by the detergent even from non-S-phase cells. It was interpreted as the evidence of PCNA integration into the repair complex and of the participation of this protein in repair synthesis in vivo. In the present work the data were obtained indicating that the role of PCNA in cell response to UV-damage was not confined only to its possible involvement in repair synthesis. With the help of confocal microscopy it was established that in Triton X-100-extracted normal cells PCNA did not colocalize with the well known excision repair protein XPB/ERCC3, defective in cells from Xeroderma pigmentosum (complementation group B) patients. XPB-protein is induced by UV-irradiation in normal cells, and this induction is not observed in repair deficient cells. However, in such cells UV-light induces a detergent-resistant form of PCNA, and this form is obviously not connected with repair. It cannot be excluded that a rapid PCNA immobilization immediately after UV-irradiation of cells is needed for the facilitation of photochemical damage bypass during the subsequent replication of genome.     

Hypomethylation in cervical tissue: is there a correlation with folate status?

5-Aminolevulinic acid (ALA) is the first intermediate substrate in the heme synthetic pathway and is the substrate of aminolevulinic acid dehydratase (ALAD, porphobilinogen synthase). Because lead effectively inhibits ALAD activity, resulting in accumulation of ALA in urine and blood, urinary ALA (ALAU) has been used as a biomarker for lead exposure or early biologic effect of lead. Intraindividual variation in urinary excretion of ALA requires the use of 24-hour urine samples or adjustment of single urine samples by other normalizing variables, such as urinary creatinine concentration. Previous studies of ALAU concentration have used various adjustment methods; however, few have compared creatinine-adjusted ALAU concentration with ALA concentration in plasma (ALAP) from subjects with low (< 30 micrograms/dL) to moderate (< 60 micrograms/dL) levels of blood lead. To determine if creatinine-adjusted ALAU is associated with ALAP, we measured ALAU, ALAP, and urinary creatinine in 65 Korean lead workers with blood lead concentrations in the range of 14-60 micrograms/dL. ALAU, ALAU/creatinine, or ALAU/log creatinine all correlated with ALAP. However, ALAU/creatinine correlated more closely with ALAP based on Spearman's r (rs = 0.40, P, = 0.0009), supporting the use of ALA/creatinine in single urine samples as a surrogate for ALAP.     

Biodegradation pathway of 2-chlorodibenzo-p-dioxin and 2-chlorodibenzofuran in the biphenyl-utilising strain JB1

The biphenyl-utilising Burkholderia (previously Alcaligenes) strain JB1 is also able to degrade a number of chlorinated dibenzo-p-dioxins and dibenzofurans. In this study, 4-chlorocatechol and a chlorotrihydroxydiphenyl ether were identified as metabolites of 2-chlorodibenzo-p-dioxin. 5-Chlorosalicylic acid and a chlorotrihydroxybiphenyl were metabolites of 2-chlorodibenzofuran. These results show that degradation of these compounds follows pathways in which the initial reaction is angular dioxygenation, followed by cleavage of an ether bridge. This pathway is similar to that used by dibenzofuran-degrading strains such as Sphingomonas sp. strain RW1.     

The role of fine-needle aspiration biopsy in the initial diagnosis of pediatric bone and soft tissue tumors: an institutional experience

A 13-year-old girl developed atonic seizure at 2 years of age. At the age of 10 years, gelastic seizures were noted. Magnetic resonance imaging (MRI) revealed a hypothalamic mass protruding down into the basal cistern and up into the third ventricle. An interictal electroencephalogram (EEG) showed paroxysmal spike and wave complex discharges. Since the seizures failed to respond to medical therapy, it was decided to try to control them by removing the mass. The operation was carried out through an interhemispheric trans-lamina terminalis approach. The lesion was so similar to normal brain tissue that the resection had to be limited enough to avoid complications. Histological examination of the mass showed a hamartoma. Postoperative MRI showed residual mass, but no seizure has been noted since the operation. The EEG recorded one year after the operation showed no spike and wave complex discharge, although she was still on anticonvulsant drugs. The authors propose that surgical therapy should be considered as a treatment for intractable gelastic epilepsy with hypothalamic hamartoma and that the first operation should be conservative enough to avoid complications, because it can bring about good results even if it is only a partial resection.