Regional chromosomal assignment of the Kell blood group locus (KEL) to chromosome 7q33-q35 by fluorescence in situ hybridization: evidence for the polypeptide nature of antigenic variation

The gene encoding the Kell blood group polypeptide has been localized to chromosome 7q33-35 by in situ hybridization using a biotinylated 1.1-kb DNA fragment containing the 3 half of the human cDNA. This assignment is in accord with genetic localization using antigenic variation as a marker, and strongly suggests that Kell antigenic determinants are part of the polypeptide chain rather than the associated sugar molecules.     

The spatial variability of soil resources following long-term disturbance

The spatial distributions of selected soil properties in two adjacent sites in southwest Michigan were examined to evaluate the potential effects of chronic disturbance on resource heterogeneity. One site was a cultivated field that had been cleared, plowed, and cropped annually for decades prior to sampling while the other, uncultivated field was cleared of original forest in 1960 after which it was mown annually but never plowed or cropped. We took replicate samples from a 330-point unaligned grid across the sites for soil pH, gravimetric moisture, inorganic phosphorus, total carbon, and net nitrification and nitrogen mineralization potentials. Soils in the cultivated site contained less than half as much carbon as in the uncultivated site, but had higher levels of inorganic phosphorus and moisture, and higher soil pH. Potential net nitrogen mineralization and nitrification rates did not differ between sites. Geostatistical analysis showed that almost all properties examined were strongly autocorelated within each site; structural variance as a proportion of sample variance ranged from 30–95% for all properties, and for any given property differed little between sites. The distance over which this dependence was expressed, however, was for all properties but pH substantially less in the uncultivated site (7–26 m) as compared to the tilled site (48–108m), especially for total C and net nitrification and N mineralization. These results suggest that the spatial pattern and scale of soil variability can differ markedly among edaphically identical sites and that these differences can be related to disturbance history.     

Inflammatory Bowel Disease and Risk of Adverse Pregnancy Outcomes

Background and Objectives

Existing data on pregnancy complications in inflammatory bowel disease (IBD) are inconsistent. To address these inconsistencies, we investigated potential associations between IBD, IBD-related medication use during pregnancy, and pregnancy loss, pre-eclampsia, preterm delivery, Apgar score, and congenital abnormalities.

Methods

We conducted a cohort study in >85,000 Danish National Birth Cohort women who were pregnant in the period 1996-2002 and had information on IBD, IBD-related medication use (systemic or local corticosteroids, 5-aminosalicylates), pregnancy outcomes and potential confounders. We evaluated associations between IBD and adverse pregnancy/birth outcomes using Cox regression and log-linear binomial regression.

Results

IBD was strongly and significantly associated with severe pre-eclampsia, preterm premature rupture of membranes and medically indicated preterm delivery in women using systemic corticosteroids during pregnancy (hazard ratios [HRs] >7). IBD was also associated with premature preterm rupture of membranes in women using local corticosteroid medications (HR 3.30, 95% confidence interval [CI] 1.33-8.20) and with medically indicated preterm delivery (HR 1.91, 95% CI 0.99-3.68) in non-medicated women. Furthermore, IBD was associated with low 5-minute Apgar score in term infants (risk ratio [RR] 2.19, 95% CI 1.03-4.66). Finally, Crohn’s disease (but not ulcerative colitis) was associated with major congenital abnormalities in the offspring (RR 1.85, 95% CI 1.06-3.21). No child with a congenital abnormality born to a woman with IBD was exposed to systemic corticosteroids in utero.

Conclusion

Women with IBD are at increased risk of severe pre-eclampsia, medically indicated preterm delivery, preterm premature rupture of membranes, and delivering infants with low Apgar score and major congenital malformations. These associations are only partly explained by severe disease as reflected by systemic corticosteroid use.     

应用于中华鲟的Pop-up标志固定方法

简要介绍了应用于中华鲟(Acipenser sinensis)的pop-up标志固定方法,包括预埋体的制作、植入及pop-up标志悬挂等技术,并对其应用效果进行了评价。     

Substrate-specific differences in the rate of bile acid carrier reorientation: studies on human placental basal vesicles.

The initial rate of transport of the bile acid glycocholic acid (GCA) has been measured in influx and efflux across placental basal membrane vesicles, and the mechanism of inhibition of its transport by the analogue taurochenodeoxycholic acid (TCDCA) analysed kinetically. This analogue, although trans-stimulating GCA efflux, inhibits influx in a way which does not depend upon substrate concentration; moreover, its potency as an inhibitor is markedly influenced by whether it is placed on one or on both sides of the vesicles membrane. These findings can be accounted for by postulating that both GCA and TCDCA are translocated through the carrier, but that the rate of loaded carrier reorientation is higher than that of the free carrier only when loaded with TCDCA and not with GCA.     

Rates and Factors Associated with Major Modifications to First-Line Combination Antiretroviral Therapy: Results from the Asia-Pacific Region

Background

In the Asia-Pacific region many countries have adopted the WHO’s public health approach to HIV care and treatment. We performed exploratory analyses of the factors associated with first major modification to first-line combination antiretroviral therapy (ART) in resource-rich and resource-limited countries in the region.

Methods

We selected treatment naive HIV-positive adults from the Australian HIV Observational Database (AHOD) and the TREAT Asia HIV Observational Database (TAHOD). We dichotomised each country’s per capita income into high/upper-middle (T-H) and lower-middle/low (T-L). Survival methods stratified by income were used to explore time to first major modification of first-line ART and associated factors. We defined a treatment modification as either initiation of a new class of antiretroviral (ARV) or a substitution of two or more ARV agents from within the same ARV class.

Results

A total of 4250 patients had 961 major modifications to first-line ART in the first five years of therapy. The cumulative incidence (95% CI) of treatment modification was 0.48 (0.44–0.52), 0.33 (0.30–0.36) and 0.21 (0.18–0.23) for AHOD, T-H and T-L respectively. We found no strong associations between typical patient characteristic factors and rates of treatment modification. In AHOD, relative to sites that monitor twice-yearly (both CD4 and HIV RNA-VL), quarterly monitoring corresponded with a doubling of the rate of treatment modifications. In T-H, relative to sites that monitor once-yearly (both CD4 and HIV RNA-VL), monitoring twice-yearly corresponded to a 1.8 factor increase in treatment modifications. In T-L, no sites on average monitored both CD4 & HIV RNA-VL concurrently once-yearly. We found no differences in rates of modifications for once- or twice-yearly CD4 count monitoring.

Conclusions

Low-income countries tended to have lower rates of major modifications made to first-line ART compared to higher-income countries. In higher-income countries, an increased rate of RNA-VL monitoring was associated with increased modifications to first-line ART.     

Microbialite response to an anthropogenic salinity gradient in Great Salt Lake,Utah

A railroad causeway across Great Salt Lake, Utah (GSL), has restricted water flow since its construction in 1959, resulting in a more saline North Arm (NA; 24%–31% salinity) and a less saline South Arm (SA; 11%–14% salinity). Here, we characterized microbial carbonates collected from the SA and the NA to evaluate the effect of increased salinity on community composition and abundance and to determine whether the communities present in the NA are still actively precipitating carbonate or if they are remnant features from prior to causeway construction. SSU rRNA gene abundances associated with the NA microbialite were three orders of magnitude lower than those associated with the SA microbialite, indicating that the latter community is more productive. SSU rRNA gene sequencing and functional gene microarray analyses indicated that SA and NA microbialite communities are distinct. In particular, abundant sequences affiliated with photoautotrophic taxa including cyanobacteria and diatoms that may drive carbonate precipitation and thus still actively form microbialites were identified in the SA microbialite; sequences affiliated with photoautotrophic taxa were in low abundance in the NA microbialite. SA and NA microbialites comprise smooth prismatic aragonite crystals. However, the SA microbialite also contained micritic aragonite, which can be formed as a result of biological activity. Collectively, these observations suggest that NA microbialites are likely to be remnant features from prior to causeway construction and indicate a strong decrease in the ability of NA microbialite communities to actively precipitate carbonate minerals. Moreover, the results suggest a role for cyanobacteria and diatoms in carbonate precipitation and microbialite formation in the SA of GSL.     

Studies of in vitro activation and differentiation of human B lymphocytes. I. Phenotypic and functional characterization of the B cell population responding to anti-Ig antibody

Investigation of the activation of splenic B cells by anti-immunoglobulin (Ig) antibody has enabled us to characterize the anti-Ig-responsive B cell and to analyze the phenotypic changes which accompany proliferation and differentiation. The anti-Ig antibody-responsive B cell population was characterized by the expression of high levels of the B2 antigen and represented approximately 40% of splenic B cells. Brisk mitogenesis which peaked at 3 to 4 days was induced by anti-Ig antibody. The proliferative phase was characterized phenotypically by a dramatic decline in B2 antigen expression, with most cells showing no detectable B2 by 4 days post-activation. The other hallmark of this phase was de novo expression of a group of "activation antigens." These included the B cell-restricted antigens B-LAST 1, BB1, and B5, and the T cell-associated interleukin 2 receptor and T12 antigens. Concomitantly, B1, B4, and Ia expression increased, the increase being roughly proportional to the increase in cell size. After day 4, the mitogenic response progressively diminished, while Ig synthesis increased. During this differentiation phase, cell surface antigens again displayed a distinct sequence of changes. The five activation antigens and the B1, B4, and Ia antigens began to decrease. However, two markers, T10 and PCA-1, which are found on plasmacytomas, appeared and their level of expression steadily increased. These changes and the appearance of morphologically identifiable plasma cells required the presence of T cells in this system. T cell supernatants alone induced Ig secretion but did not induce expression of PCA-1 or the appearance of cells with plasma cell morphology. The culture system developed in this study has allowed us to analyze the antigenic changes following activation by anti-Ig antibody. This sequence of changes has not only permitted the identification of antigens which, by their appearance at distinct stages may have an important role in proliferation and differentiation of B cells, but also provides us with the means of studying the function of each antigen.