Traces of human migrations in Helicobacter pylori populations

Helicobacter pylori, a chronic gastric pathogen of human beings, can be divided into seven populations and subpopulations with distinct geographical distributions. These modern populations derive their gene pools from ancestral populations that arose in Africa, Central Asia, and East Asia. Subsequent spread can be attributed to human migratory fluxes such as the prehistoric colonization of Polynesia and the Americas, the neolithic introduction of farming to Europe, the Bantu expansion within Africa, and the slave trade.     

Survey of internal parasites in Western Australian pig herds. 1. Prevalence

Between September 1982 and March 1984, 101 Western Australian piggeries with 15 or more sows were surveyed to determine the prevalence of internal parasites and examine the relationship between parasitism and management practices. Faecal samples were collected from 20 pigs in 4 age groups in randomly selected piggeries, and examined for the presence of eggs of helminth parasites and protozoan cysts. Evidence of nematode parasites was found in 79% of piggeries. Sows were more commonly affected than other classes of pigs with worm eggs being found in 68% of herds. Oesophagostomum spp was the most prevalent worm species, being found in pigs from 65% of piggeries and in sows in 60% of herds. Ascaris suum was the most common species of worm found in growing pigs. There was no evidence of infection with either Metastrongylus spp or Strongyloides spp in any of the herds sampled. Oocysts of coccidia were found in pigs from 56% of piggeries and Balantidium coli cysts were detected in pigs from 42% of piggeries sampled.     

Iodine desorption from rice paddy soil

Laboratory experiments on the desorption phenomena of iodine from rice paddy soil under waterlogged conditions, with a special reference to soil redox potential (Eh) and pH, have been conducted. Radioiodine tracer (1251), added to the soil, was readily sorbed on it. At the beginning of the waterlogging, the iodine desorption was low. However, iodine was desorbed into soil solution with time. The iodine desorption was enhanced markedly by the addition of organic substances such as straw pieces and glucose to the soil. Cultivation of rice plants in soil also affected the iodine desorption, suggesting root exudates and/or root autolysis might be participating in the desorption process. Eh dropped considerably after soil was waterlogged due to microbial metabolisms. Particularly low Eh values were observed in soils with plants and also with added organic substances. A negative correlation was seen between the desorption and soil Eh. High desorption was frequently observed when the Eh dropped to about -100 mV or below. Due to the reducing conditions (low Eh) by waterlogging, iodine in soil was leached into the soil solution; consequently total iodine concentration in paddy soil was considerably lower than forest and upland field soils. These iodine desorption phenomena under anaerobic conditions should be considered in assessing transfer of the long-lived radioiodine (129I) in the environment, especially in rice fields and marshland.     

Seroprevalence of and agroecological risk factors for Mycobacterium avium subspecies paratuberculosis and neospora caninum infection among adult beef cattle in cow-calf herds in Alberta, Canada

A province-wide cross-sectional seroprevalence and agroecological risk factor study of Mycobacterium avium subspecies paratuberculosis (MAP) and Neospora caninum (NC) infection among cattle in 100 cow-calf herds in Alberta was conducted. The seroprevalence of MAP in adult cattle was 1.5% across all herds. Using a widely accepted herd test cutpoint of 2 or more seropositive cows out of 30 animals tested, 7.9% of herds were estimated to be infected (95% confidence interval (CI): 2.3-23.4%). Seroprevalence of MAP differed by agroecological region; specifically, cattle and herds in areas with high soil pH (> 7.0), southern latitudes, and arid climates had a moderately reduced risk of infection (P < 0.10). Seroprevalence of NC infection was 9.7% among adult beef cattle province-wide--these levels also varied by agroecological region--with 91.0% of herds infected overall.     

Development and characterization of monoclonal antibodies to subgroup A avian leukosis virus

Avian leukosis virus subgroup A (ALV‐A) is a retrovirus which infects egg‐type chickens and is the main pathogen of lymphoid leukosis (LL) and myeloid leukosis (ML). In order to greatly enhance the diagnosis and treatment of clinical avian leukemia, two monoclonal antibodies (MAbs) to ALV‐A were developed by fusion between SP2/0 and spleen cells from mice immunized with expressed ALV‐A env‐gp85 protein. Using immunofluorescence assay (IFA), two MAbs reacted with ALV‐A, but not with subgroups B and J of ALV. Western blot tests showed that molecular weight of ALV‐A envelope glycoprotein recognized by MAbs was about 53 kD. Isotyping test revealed that two MAbs (A5C1 and A4C8) were IgG1 isotypes. These MAbs can be used for diagnosis and epidemiology of ALV‐A.     

Aggregate stability in range sandy loam soils Relationships with runoff and erosion

The spatial variability of soil aggregate stability and its relationship to runoff and soil erosion were examined in a catena of soils and vegetation in a semiarid environment at the Rambla Honda field site (Tabernas, Almería, SE Spain) to evaluate the validity of structural stability as a soil erosion indicator in sandy loam range soils. The influence of soil properties and topography on the variability of aggregate stability was also examined. Methods include: 1) aggregate stability assessment at 12 sites (3 repetitions per site) on the hillslope by two methods: a) aggregate size distribution by dry sieving b) water drop test; 2) soil organic carbon content; 3) particle size distribution determination; 4) terrain attributes derived from a digital elevation model (1-m resolution); 5) monitoring runoff and erosion for nearly 3 years in eight (10 × 2 m) plots distributed over the hillslope. Results: 41% of the average soil mass is formed by > 2-mm aggregates. However, wet aggregate stability is poor, with a mean (of a total of 1440 aggregates) of only 26 drop impacts necessary to break up a wet aggregate (pF = 1). Significant relationships were found in the number of water drops required for aggregate breakdown and runoff and erosion rates. However, no significant relationships between the mean weight diameter of aggregates under dry conditions and runoff or erosion rates were observed. The relationships of aggregates with other soil properties, hillslope position and proximity to plants are also analysed. The most significant correlation found was between the number of drop impacts and soil organic matter content. The stability of topsoil aggregates seems to be a valuable indicator of field-assessed runoff and inter-rill erosion of sandy loam range soils under semiarid conditions.     

Geographical variation of the skull morphology of the common tree shrew (Tupaia glis).

Geographical variation was examined morphologically in the common tree shrew (Tupaia glis) in some Indochinese and Malayan regions. Osteometrical examination and principal component analysis elucidated the morphological differences among various populations. The populations from southern and western Thailand were distinguished morphologically from the other populations. Variation in males from south Thailand and Kuala Lumpur suggests that the Isthmus of Kra may have an influence on the variation of skull morphology. However, the Isthmus of Kra was not completely considered as a factor of geographical separation in this species, because we could not confirm the separation in skull size and shape between the localities at least in females. While, the Kanchanaburi population in western Thailand was significantly smaller than the other population in skull size, and constituted the morphologically separable group in our study.     

Tetracycline-resistance genes of Clostridium perfringens, Clostridium septicum and Clostridium sordellii isolated from cattle affected with malignant edema

The minimal inhibitory concentrations (MICs) of 10 antimicrobial agents against a total of 33 isolates of Clostridium perfringens, Clostridium septicum and Clostridium sordellii from cattle affected with malignant edema in Japan was determined. The low MIC activities of benzylpenicillin confirm the place of benzylpenicillin as the antibiotics of choice for treatment of malignant edema. Five (22%) of 23 C. septicum strains, five (71%) of seven C. perfringens strains and all strains of C. sordellii showed resistance to oxytetracycline. These oxytetracycline-resistant strains carried tetracycline-resistance genes [tetA(P), tetA408(P), tetB(P) and tetM]. The sequences of the tetracycline-resistance genes of some C. septicum strains were completely or nearly completely identical to those of strains belonging to other clostridiual species. This is the first report of resistance of C. septicum to tetracycline.     

Determination of Lipid Peroxidation and Fatty Acid Compositions in the Caviars of Rainbow Trout and Carp

In this study, roes obtained from carp (Cyprinus carpio carpio) that were caught in Keban Dam Lake (Turkey) and cultured rainbow trout (Oncorhynchus mykiss) were processed as caviar, and the products were stored at + 4 C°. Lipid peroxidation and the compositions of fatty acids of these products were assessed during production and storage period. The result of fatty analyses showed that palmitic acid (16:0), stearic acid (18:0), palmitoleic acid (16:1), oleic acid (18:1), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA), which are all essential fatty acids, were determined in the caviars of the roes obtained from rainbow trout and carp. According to results of chemical analyses, there were no significant differences in thiobarbituric acid reactive substances (TBARs) between rainbow trout and carp caviars (p > 0.05), but malondialdehyde (MDA) levels were found to be statistically significant (p < 0.01). It can be concluded that caviars obtained from both rainbow trout and carp roes are rich in fatty acids and take a part in a balanced and healthy diet.     

王爱华教授辨治溃疡性结肠炎经验

湖南省名中医王爱华教授认为脾胃气虚为溃疡性结肠炎的发病之本,湿热为致病之标,热毒为下血之因,血瘀为局部病理变化,肠疡为局部病理表现,日久则病及于肾,脾肾双亏,提出健脾助运是根本、调气和血辅其治、清热化湿贯其中的治疗方法。