Hydrogen sulfide production from subgingival plaque samples

Periodontitis is a polymicrobial anaerobe infection. Little is known about the dysbiotic microbiota and the role of bacterial metabolites in the disease process. It is suggested that the production of certain waste products in the proteolytic metabolism may work as markers for disease severity. Hydrogen sulfide (H2S) is a gas produced by degradation of proteins in the subgingival pocket. It is highly toxic and believed to have pro-inflammatory properties. We aimed to study H2S production from subgingival plaque samples in relation to disease severity in subjects with natural development of the disease, using a colorimetric method based on bismuth precipitation. In remote areas of northern Thailand, adults with poor oral hygiene habits and a natural development of periodontal disease were examined for their oral health status. H2S production was measured with the bismuth method and subgingival plaque samples were analyzed for the presence of 20 bacterial species with the checkerboard DNA-DNA hybridization technique. In total, 43 subjects were examined (age 40-60 years, mean PI 95 ± 6.6%). Fifty-six percent had moderate periodontal breakdown (CAL > 3 < 7 mm) and 35% had severe periodontal breakdown (CAL > 7 mm) on at least one site. Parvimonas micra, Filifactor alocis, Porphyromonas endodontalis and Fusobacterium nucleatum were frequently detected. H2S production could not be correlated to periodontal disease severity (PPD or CAL at sampled sites) or to a specific bacterial composition. Site 21 had statistically lower production of H2S (p = 0.02) compared to 16 and 46. Betel nut chewers had statistically significant lower H2S production (p = 0.01) than non-chewers. Rapid detection and estimation of subgingival H2S production capacity was easily and reliably tested by the colorimetric bismuth sulfide precipitation method. H2S may be a valuable clinical marker for degradation of proteins in the subgingival pocket.

Do light truck vehicles (LTV) impose greater risk of pedestrian injury than passenger cars? A meta-analysis and systematic review

OBJECTIVE

Pedestrian crashes present a growing challenge for public health trauma and road safety researchers around the world. They are associated with substantial morbidity, mortality, and cost, yet there is an international lack of published work on the topic, especially when compared with vehicle occupant safety studies. Our review attempts to quantify the risk of fatal injury among vulnerable road users. The specific objective of this systematic review and meta-analysis is to quantify and compare the impact of light truck vehicles (LTVs) versus conventional cars on pedestrian fatal injury.

METHODS

A protocol was developed using methods of the Cochrane Collaboration. We conducted a search for the studies in bibliographic databases that included ATI (Australian Transport Index); Cochrane Injuries Group Specialized Register; EMBASE; ERIC; MEDLINE; National Research Register; PsycINFO; Road Res (ARRB); SIGLE; Science (and Social Science) Citation Index; TRANSPORT (NTIS, TRIS, TRANSDOC, IRRD). Web sites of traffic and road accident research bodies, government agencies, and injury prevention organizations were searched for grey literature. Reference lists from selected papers or topic reviews were scanned for potentially relevant papers.

RESULTS

Our initial search identified 878 potentially eligible studies. After thorough review by three of the researchers a total of 12 studies were included in the systematic review, 11 of which were included in the meta-analysis. The overall pooled odds ratio for the risk of fatal injury in pedestrian collisions with LTVs compared to conventional cars was odds ratio 1.54, 95 percent confidence interval 1.15-1.93, p = 0.001. Thus, the risk for pedestrians of sustaining fatal injury is 50 percent greater in collisions with LTVs than in collisions with conventional cars.

CONCLUSIONS

Our systematic review and meta-analysis suggests that LTVs pose a greater risk of pedestrian injury death compared to conventional cars. These findings have important implications for the automotive industry and the safety of vulnerable road users.

Phylogenetic analysis of spring viraemia of carp virus isolates from Austria indicates the existence of at least two subgroups within genogroup Id

Genetic relationships between 22 spring viraemia of carp virus (SVCV) isolates from Austria collected between 1994 and 2007 were determined based on the partial nucleotide sequence of the glycoprotein gene (G gene). Phylogenetic analyses located all Austrian isolates except one in genogroup Id. One isolate collected in 2007 was placed within the SVCV Ia genogroup. More importantly, the study also revealed 3 distinct clusters within genogroup Id, designated Id1, Id2 and Id3. Existence of subgroups Id2 and Id3 within the genogroup Id was supported by high bootstrap values. The genetic clustering could neither be linked to host species nor to geographic localization of fish farms. Furthermore, no clear link could be established between the pathological lesions and phylogenetic relationship. However, time-dependent division of the isolates was observed. Viruses from the Id1 cluster were mainly sampled in Austria in the 1990s and up until 2003, whereas all viruses from the Id2 subgroup were isolated after 2003.