Investigating the Role of Small, Acid-Soluble Spore Proteins (SASPs) in the Resistance of Clostridium Perfringens Spores to Heat.

BACKGROUND: Clostridium perfringens type A food poisoning is caused by enterotoxigenic C. perfringens type A isolates that typically possess high spore heat-resistance. The molecular basis for C. perfringens spore heat-resistance remains unknown. In the current study, we investigated the role of small, acid-soluble spore proteins (SASPs) in heat-resistance of spores produced by C. perfringens food poisoning isolates. RESULTS: Our current study demonstrated the presence of all three SASP-encoding genes (ssp1, 2 and 3) in five surveyed C. perfringens clinical food poisoning isolates. beta-Glucuronidase assay showed that these ssp genes are expressed specifically during sporulation. Consistent with these expression results, our study also demonstrated the production of SASPs by C. perfringens food poisoning isolates. When the heat sensitivities of spores produced by a ssp3 knock-out mutant of a C. perfringens food poisoning isolate was compared with that of spores of the wild-type strain, spores of the ssp3 mutant were found to exhibit a lower decimal reduction value (D value) at 100 degrees C than exhibited by the spores of wild-type strain. This effect was restored by complementing the ssp3 mutant with a recombinant plasmid carrying wild-type ssp3, suggesting that the observed differences in D values between spores of wild-type versus ssp3 mutant was due to the specific inactivation of ssp3. Furthermore, our DNA protection assay demonstrated that C. perfringens SASPs can protect DNA from DNase I digestion. CONCLUSION: The results from our current study provide evidences that SASPs produced by C. perfringens food poisoning isolates play a role in protecting their spores from heat-damage, which is highly significant and relevant from a food safety perspective. Further detailed studies on mechanism of action of SASPs from C. perfringens should help in understanding the mechanism of protection of C. perfringens spores from heat-damage.

Mercury in the Ocean

Making seafood choices isn't easy for consumers who want to minimize exposure to mercury but also take advantage of healthy Omega-3 fatty acids. Rob Mason's research on mercury in various ocean fish and shellfish, and his discussion of what factors are important to consider, helps readers make wise choices.

Volunteers Opening Doors: the Five Keys to Lead Safety

Millions of houses and apartments built before 1978 have paint that contains lead. Chips, dust, and fumes from this paint can be very dangerous if they are not handled properly. Lead is particularly hazardous to unborn babies, infants, and young children. Volunteers in painting and housing-rehabilitation programs often work in homes that contain lead paint. The work they perform can create a lead hazard if they disturb this paint and produce paint chips or dust. Volunteers Opening Doors is a video program for these volunteers. It explains how volunteers can protect housing residents,themselves, and their families from lead poisoning by using the five keys to lead safety: 1. Protect residents and their belongings. 2. Prepare the work area. 3. Protect yourself from dust and debris. 4. Work wet. 5. Work clean.

RNA polymerase II large subunit degradation induced by ecteinascidin 743: Molecular characterization and subsequent rational investigation of antitumor mechanisms in cancers with clinical response

Ecteinascidin 743 (Et-743), which is a novel DNA minor groove alkylator with a unique spectrum of antitumor activity, is currently being evaluated in phase II/III clinical trials. Although the precise molecular mechanisms responsible for the observed antitumor activity are poorly understood, recent data suggests that post-translational modifications of RNA polymerase II Large Subunit (RNAPII LS) may play a central role in the cellular response to this promising anticancer agent. The stalling of an actively transcribing RNAPII LS at Et-743-DNA adducts is the initial cellular signal for transcription-coupled nucleotide excision repair (TC-NER). In this manner, Et-743 poisons TC-NER and produces DNA single strand breaks. Et-743 also inhibits the transcription and RNAPII LS-mediated expression of selected genes. Because the poisoning of TC-NER and transcription inhibition are critical components of the molecular response to Et-743 treatment, we have investigated if changes in RNAPII LS contribute to the disruption of these two cellular pathways. In addition, we have studied changes in RNAPII LS in two tumors for which clinical responses were reported in phase I/II clinical trials: renal cell carcinoma and Ewing's sarcoma. Our results demonstrate that Et-743 induces degradation of the RNAPII LS that is dependent on active transcription, a functional 26S proteasome, and requires functional TC-NER, but not global genome repair. Additionally, we have provided the first experimental data indicating that degradation of RNAPII LS might lead to the inhibition of activated gene transcription. A set of studies performed in isogenic renal carcinoma cells deficient in von Hippel-Lindau protein, which is a ubiquitin-E3-ligase for RNAPII LS, confirmed the central role of RNAPII LS degradation in the sensitivity to Et-743. Finally, we have shown that RNAPII LS is also degraded in Ewing's sarcoma tumors following Et-743 treatment and provide data to suggest that this event plays a role in decreased expression of the Ewing's sarcoma oncoprotein, EWS-Fli1. Altogether, these data implicate degradation of RNAPII LS as a critical event following Et-743 exposure and suggest that the clinical activity observed in renal carcinoma and Ewing's sarcoma may be mediated by disruption of molecular pathways requiring a fully functional RNAPII LS. ^

Secondary data analysis of lead screening compliance in high-risk children

Introduction. Despite the ban of lead-containing gasoline and paint, childhood lead poisoning remains a public health issue. Furthermore, a Medicaid-eligible child is 8 times more likely to have an elevated blood lead level (EBLL) than a non-Medicaid child, which is the primary reason for the early detection lead screening mandate for ages 12 and 24 months among the Medicaid population. Based on field observations, there was evidence that suggested a screening compliance issue. Objective. The purpose of this study was to analyze blood lead screening compliance in previously lead poisoned Medicaid children and test for an association between timely lead screening and timely childhood immunizations. The mean months between follow-up tests were also examined for a significant difference between the non-compliant and compliant lead screened children. Methods. Access to the surveillance data of all childhood lead poisoned cases in Bexar County was granted by the San Antonio Metropolitan Health District. A database was constructed and analyzed using descriptive statistics, logistic regression methods and non-parametric tests. Lead screening at 12 months of age was analyzed separately from lead screening at 24 months. The small portion of the population who were also related were included in one analysis and removed from a second analysis to check for significance. Gender, ethnicity, age of home, and having a sibling with an EBLL were ruled out as confounders for the association tests but ethnicity and age of home were adjusted in the nonparametric tests. Results. There was a strong significant association between lead screening compliance at 12 months and childhood immunization compliance, with or without including related children (p<0.00). However, there was no significant association between the two variables at the age of 24 months. Furthermore, there was no significant difference between the median of the mean months of follow-up blood tests among the non-compliant and compliant lead screened population for at the 12 month screening group but there was a significant difference at the 24 month screening group (p<0.01). Discussion. Descriptive statistics showed that 61% and 56% of the previously lead poisoned Medicaid population did not receive their 12 and 24 month mandated lead screening on time, respectively. This suggests that their elevated blood lead level may have been diagnosed earlier in their childhood. Furthermore, a child who is compliant with their lead screening at 12 months of age is 2.36 times more likely to also receive their childhood immunizations on time compared to a child who was not compliant with their 12 month screening. Even though there was no statistical significant association found for the 24 month group, the public health significance of a screening compliance issue is no less important. The Texas Medicaid program needs to enforce lead screening compliance because it is evident that there has been no monitoring system in place. Further recommendations include a need for an increased focus on parental education and the importance of taking their children for wellness exams on time.^

Jean-Martin Charcot - Neurologist by Avocation, Nephrologist by Yearning

In an age of medical advances and specialization, Jean-Martin Charcot (1825-1893) helped found the discipline of neurology and in 1882 was appointed the first professor of Diseases of the Nervous System in France. As an investigator with broad interests and vast knowledge Charcot contributed to several other disciplines. An early mentor and dominant figure in Charcot's formative years was Pierre Rayer (1793-1867), famous for his seminal contributions to the study of the kidney, who gifted Charcot with his passion for clinical pathological correlations and likely a yearning for the study of kidney diseases. Famous for the clarity and incisiveness of his formal teaching presentations, Charcot lectured on the kidney at the Faculty of Medicine in Paris in 1877. Translated into English and published as a book titled Lectures on Bright's Disease, they became widely accessible and quoted in the literature through the present. In addition, at a time that he was already concentrating on the study of neurological disorders, Charcot maintained his life-long interest in the kidney and published original studies on the pathological changes of the kidney in gout and experimental lead poisoning, as well as supporting a study of hysterical ischuria by his students.

Problemas de salud de los jornaleros tamaulipecos empleados con visas h-2a en Estados Unidos

Desde hace dos décadas los jornaleros tamaulipecos han recibido un considerable número de visas H-2A para trabajar en la agricultura en Estados Unidos. Los empleadores estadounidenses muestran una cierta preferencia por los jornaleros tamaulipecos, ya que la cercanía de Tamaulipas a la frontera disminuye los costos de transporte, que deben ser asumidos por los empleadores. Los programas de trabajadores huéspedes para mano de obra no cualificada exponen a los trabajadores foráneos al abuso y la explotación. La falta de cumplimiento con algunas regulaciones federales como el Estándar de Protección de los Trabajadores o el Seguro de Compensación Laboral incrementa el riesgo de envenenamiento por agroquímicos y accidentes entre los jornaleros, y aquellos que sufren accidentes laborales o enfermedades no reciben atención médica. Este artículo examina los problemas de salud sufridos por los trabajadores tamaulipecos empleados con visas H-2A en la agricultura estadounidense.