Identification and characterization of a novel heme-associated cell surface protein made by Streptococcus pyogenes

Analysis of the genome sequence of a serotype M1 group A Streptococcus (GAS) strain identified a gene encoding a previously undescribed putative cell surface protein. The gene was cloned from a serotype M1 strain, and the recombinant protein was overexpressed in Escherichia coli and purified to homogeneity. The purified protein was associated with heme in a 1:1 stoichiometry. This streptococcal heme-associated protein, designated Shp, was produced in vitro by GAS, located on the bacterial cell surface, and accessible to specific antibody raised against the purified recombinant protein. Mice inoculated subcutaneously with GAS and humans with invasive infections and pharyngitis caused by GAS seroconverted to Shp, indicating that Shp was produced in vivo. The blood of mice actively immunized with Shp had significantly higher bactericidal activity than the blood of unimmunized mice. The shp gene was cotranscribed with eight contiguous genes, including homologues of an ABC transporter involved in iron uptake in gram-negative bacteria. Our results indicate that Shp is a novel cell surface heme-associated protein.     

Associations between unprocessed red and processed meat,poultry, seafood and egg intake and the risk of prostate cancer: A pooled analysis of 15 prospective cohort studies

Reports relating meat intake to prostate cancer risk are inconsistent. Associations between these dietary factors and prostate cancer were examined in a consortium of 15 cohort studies. During follow‐up, 52,683 incident prostate cancer cases, including 4,924 advanced cases, were identified among 842,149 men. Cox proportional hazard models were used to calculate study‐specific relative risks (RR) and then pooled using random effects models. Results do not support a substantial effect of total red, unprocessed red and processed meat for all prostate cancer outcomes, except for a modest positive association for tumors identified as advanced stage at diagnosis (advanced(r)). For seafood, no substantial effect was observed for prostate cancer regardless of stage or grade. Poultry intake was inversely associated with risk of advanced and fatal cancers (pooled multivariable RR [MVRR], 95% confidence interval, comparing ≥45 vs. <5 g/day: advanced 0.83, 0.70–0.99; trend test p value 0.29), fatal, 0.69, 0.59–0.82, trend test p value 0.16). Participants who ate ≥25 versus <5 g/day of eggs (1 egg ～ 50 g) had a significant 14% increased risk of advanced and fatal cancers (advanced 1.14, 1.01–1.28, trend test p value 0.01; fatal 1.14, 1.00–1.30, trend test p value 0.01). When associations were analyzed separately by geographical region (North America vs. other continents), positive associations between unprocessed red meat and egg intake, and inverse associations between poultry intake and advanced, advanced(r) and fatal cancers were limited to North American studies. However, differences were only statistically significant for eggs. Observed differences in associations by geographical region warrant further investigation.     

Imprinted polymers as drug delivery vehicles for metal-based anti-inflammatory drug

A drug delivery system based on metal-chelate imprinting is described for the first time for a metal-based drug, copper salicylate. Metal-chelate embedded polymer (MCEP) material was prepared by adding 2 equiv. of 4-vinyl pyridine, 8 equiv. of 2-hydroxyethyl methacrylate, 32 equiv. of ethyleneglycoldimethacrylate to 1 equiv. of copper salicylate in 10 ml of 2-methoxyethanol and then polymerizing thermally in the presence of 2,2'-azobisisobutyronitrile as initiator. The removal of the embedded copper salicylate from MCEP to prepare metal-chelate imprinted polymer (MCIP) was assessed by X-ray photoelectron spectroscopy (XPS), flame atomic absorption spectroscopy (FAAS) and high performance liquid chromatography (HPLC) techniques. Conventional or non-imprinted polymer material was prepared in a similar manner to MCEP, but without the addition of copper salicylate to the synthesis recipe. The drug release behaviour was examined in vitro with polymer materials having different template to monomer ratio, different crosslinker density and with polymer material loaded with copper salicylate to different extent. Detailed drug release studies with the drug loaded to MCIP and NIP materials unequivocally establish the higher and sustained release of the therapeutic agent over several days in addition to higher drug loading capacity with the former material.     

S-Ethyl-N,N-dipropylthiocarbamate Exposure and Cancer Incidence among Male Pesticide Applicators in the Agricultural Health Study: A Prospective Cohort

Background

The Agricultural Health Study (AHS) is a prospective cohort study of licensed pesticide applicators from Iowa and North Carolina enrolled between 1993 and 1997. EPTC (S-ethyl-N,N-dipropylthiocarbamate) is a thiocarbamate herbicide used in every region of the United States. The U.S. Environmental Protection Agency reports that EPTC is most likely not a human carcinogen; however, the previous epidemiologic data on EPTC exposure and cancer risk were limited.

Objectives

The purpose of this study was to examine cancer incidence and EPTC use in 48,378 male pesticide applicators enrolled in the AHS.

Methods

We estimated the rate ratio (RR) and 95% confidence intervals (CIs) for all cancers and selected cancer sites using Poisson regression. We assessed EPTC exposure using two quantitative metrics: lifetime exposure days and intensity-weighted lifetime exposure days, a measure that accounts for application factors that modify personal exposure likelihood.

Results

Among the 9,878 applicators exposed to EPTC, 470 incident cancer cases were diagnosed during the follow-up period ending December 2004 compared with the 1,824 cases among individuals reporting no use. Although EPTC was associated with colon cancer in the highest tertile of both lifetime exposure days and intensity-weighted lifetime days (RR = 2.09; 95% CI, 1.26–3.47 and RR = 2.05; 95% CI, 1.34–3.14, respectively) and the trend test was < 0.01 for both, the pattern of RR was not monotonic with increasing use. There was a suggestion of an association with leukemia. No other associations were observed.

Conclusion

In this analysis, EPTC use appeared to be associated with colon cancer and leukemia. However, given the relatively small number of cases in the highest exposure tertile, results should be interpreted with caution, and further investigations are needed.     

Evaluation of established breast cancer risk factors as modifiers of BRCA1 or BRCA2: a multi-center case-only analysis

The incomplete penetrance of mutations in BRCA1 and BRCA2 suggests that some combination of environmental and genetic factors modifies the risk of breast cancer in mutation carriers. This study sought to identify possible interactions between established breast cancer risk factors and BRCA1 or BRCA2 mutations using a case-only study design. Breast cancer cases that had been tested for BRCA1 and BRCA2 mutations were identified from 11 collaborating centers. Comparisons of reproductive and lifestyle risk factors were made between women with breast cancer who were positive for BRCA1 mutations (n = 283), BRCA2 mutations (n = 204), or negative for both BRCA1 and BRCA2 mutations (n = 894). Interaction risk ratios (IRRs) were calculated using multinominal logistic regression models. Compared with non-carriers, statistically significant IRRs were observed for later age at menarche among BRCA2 mutation carriers, for a greater number of pregnancies among both BRCA1 and BRCA2 mutation carriers, and for alcohol use among BRCA1 mutation carriers. Our data suggest that the risk for breast cancer among BRCA1 or BRCA2 carriers may be modified by reproductive characteristics and alcohol use. However, our results should be interpreted cautiously given the overall inconsistency in the epidemiologic literature on modifiers of BRCA1 and BRCA2.     

In vitro culture and morphological characterization of prepubertal buffalo (Bubalus bubalis) putative spermatogonial stem cell

Purpose

Spermatogonial stem cells (SSCs) have the unique ability both to self-renew and to produce progeny that undergo differentiation to spermatozoa. The present study has been carried out to develop a method to purify and enrich the pure populations of spermatogonial stem cell like cells in buffalo.

Methods

The spermatogonial cells were isolated from testes of 3–7 month old buffalo calves and disaggregated by double enzymatic digestion. Mixed population of isolated cells were then plated on Datura stramonium agglutinin (DSA) lectin coated dishes for attachment of Sertoli cells. The desired cells were obtained from suspension medium after 18 h of incubation and then loaded on discontinuous density gradient using percoll (20–65 %) and different types of spermatogonia cells were obtained at interface of each layer. These cells were cultured in vitro.

Results

Spermatogonial cells isolated have spherical outline and two or three eccentrically placed nucleoli, created a colony after proliferation during first week or immediately after passage. After 7–10 days of culture, the resulted developed colonies of spermatogonial cells expressed the spermatogonial specific genes like Plzf and VASA; and other pluripotency related markers viz. alkaline phosphtase, DBA, CD9, CD90, SSEA-1, OCT-4, NANOG and REX-1.

Conclusion

Our results show that the isolated putative spermatogonial stem cells exhibit the expression of pluripotency related and spermatogonial specific genes. This study may help to establish a long term culture system for buffalo spermatogonia.