Induction of periodontal disease via retentive ligature, lipopolysaccharide injection, and their combination in a rat model.

Periodontitis is a highly prevalent, chronic immune-inflammatory disease of the periodontium that results in the periodontium and alveolar bone loss's progressive destruction. In this study, the induction of periodontal disease via retentive ligature, lipopolysaccharide, and their combination at three different times were compared in a rat model. Seventy-two Sprague Dawley rats were distributed into four treatment groups: 1) control group with no treatment; 2) application of 4/0 nylon ligature around second maxillary molars; 3) combination of ligature and LPS injection (ligature-LPS); 4) intragingival injection of Porphyromonas gingivalis lipopolysaccharide (Pg-LPS) to the palatal mucosa of the second maxillary molars. Six rats were sacrificed from each group after 7, 14, and 30 days of periodontal disease induction. Alveolar bone loss, attachment loss, number of inflammatory cells, and blood vessels were evaluated histologically. A micro-CT scan was used as a parameter to know the rate of alveolar bone loss. Parametric data were analyzed using two-way ANOVA followed by Bonferroni correction with a significance set at 5%. Non-parametric data were analyzed using Kruskal-Wallis, followed by multiple comparisons with Bonferroni correction. The histological results revealed significant destructive changes in the periodontal tissues and alveolar bone following the ligature and ligature-LPS induction techniques. These changes were evident as early as seven days, maintained until 14 days post-treatment, and declined with time. The ligature technique was effective in inducing acute periodontal disease. The LPS injection technique did not induce alveolar bone loss, and its combination to ligature added insignificant effects.

Historical atmospheric pollution trends in Southeast Asia inferred from lake sediment records.

Fossil fuel combustion leads to increased levels of air pollution, which negatively affects human health as well as the environment. Documented data for Southeast Asia (SEA) show a strong increase in fossil fuel consumption since 1980, but information on coal and oil combustion before 1980 is not widely available. Spheroidal carbonaceous particles (SCPs) and heavy metals, such as mercury (Hg), are emitted as by-products of fossil fuel combustion and may accumulate in sediments following atmospheric fallout. Here we use sediment SCP and Hg records from several freshwater lentic ecosystems in SEA (Malaysia, Philippines, Singapore) to reconstruct long-term, region-wide variations in levels of these two key atmospheric pollution indicators. The age-depth models of Philippine sediment cores do not reach back far enough to date first SCP presence, but single SCP occurrences are first observed between 1925 and 1950 for a Malaysian site. Increasing SCP flux is observed at our sites from 1960 onward, although individual sites show minor differences in trends. SCP fluxes show a general decline after 2000 at each of our study sites. While the records show broadly similar temporal trends across SEA, absolute SCP fluxes differ between sites, with a record from Malaysia showing SCP fluxes that are two orders of magnitude lower than records from the Philippines. Similar trends in records from China and Japan represent the emergence of atmospheric pollution as a broadly-based inter-region environmental problem during the 20th century. Hg fluxes were relatively stable from the second half of the 20th century onward. As catchment soils are also contaminated with atmospheric Hg, future soil erosion can be expected to lead to enhanced Hg flux into surface waters.

Molecular and serological prevalence of Anaplasma and Ehrlichia sp. among stray dogs in East Malaysia.

Anaplasma and Ehrlichia species are important bacterial pathogens of various animal species including dogs and humans. They constitute a major health problem worldwide, especially in the tropics and sub-tropics. In order to identify the prevalence of Anaplasma and Ehrlichia sp. from dogs in the selected area, a total of 100 randomly selected clinically healthy rescued dogs from animal shelters in Sarawak and Sabah, East Malaysia (50 dogs per State) were used for this study. Whole blood was collected from these dogs and screened for presence of Anaplasma and Ehrlichia spp. using polymerase chain reaction (PCR) and commercial ELISA test (SNAP 4Dx® Plus) for detection of antigen and antibody against the two pathogens respectively. 27% (A. platys) and 33% (E. canis) of the sampled population were positive using PCR; while the serological prevalence was 29% for Anaplasma sp. and 55% for Ehrlichia sp. The results of this investigation revealed that stray dogs are potential reservoir hosts of Anaplasma and Ehrlichia sp. infection with a high prevalence in the area. The high prevalence rates detected highlights the urgent need to address the growing population of possible vectors and reservoirs for transmission in the region and also to look into the public health aspect of the disease.