Prevalence of self-reported clinically diagnosed sleep apnea according to obesity status in men and women: National Health and Nutrition Examination Survey, 2005-2006
Li C , Ford ES , Zhao G , Croft JB , Balluz LS , Mokdad AH . Prev Med 2010 51 (1) 18-23 OBJECTIVE: To estimate the prevalence of self-reported clinically diagnosed sleep apnea (diagnosed sleep apnea) according to body mass index (BMI, measure of total obesity) and waist circumference (measure of abdominal obesity) in US adults. METHODS: Data from a representative sample of 4309 US adults in the National Health and Nutrition Examination Surveys 2005-2006 were analyzed. Log-linear regression analyses with a robust variance estimator were performed to estimate the prevalence ratios (PR) and 95% confidence intervals (CIs). RESULTS: The overall crude and age-adjusted prevalence estimates of diagnosed sleep apnea were 4.7% (95% CI=4.0%-5.5%) and 4.5% (95% CI=3.9%-5.2%) in adults. Age-adjusted prevalence in men (6.1%, 95% CI=5.0%-7.3%) was higher than that in women (3.1%, 95% CI=2.1%-4.0%; P<0.01). Age-adjusted prevalence was higher for persons with total obesity (i.e., BMI > or = 30 kg/m(2)) (12.1% vs. 3.0% in men, P<0.01; 7.0% vs. 0.7% in women, P<0.01) or abdominal obesity (10.9% vs. 1.9% in men, P<0.01; 4.6% vs. 0.6% in women, P<0.01) than that for those without total obesity (BMI <30 kg/m(2)) or without abdominal obesity. CONCLUSIONS: These results from a nationally representative sample suggest that diagnosed sleep apnea is highly prevalent among adults with obesity in the general population, especially among men. |
Factors associated with the progression of fibrosis on liver biopsy in Alaska Native and American Indian persons with chronic hepatitis C
Livingston SE , Deubner H , Bruden DL , McMahon BJ , Homan CE , Townshend-Bulson LJ , Bruce MG , Hennessy TW , Williams JL , Gretch DR . Can J Gastroenterol 2010 24 (7) 445-51 BACKGROUND: Various factors influence the development and rate of fibrosis progression in chronic hepatitis C virus (HCV) infection. OBJECTIVES: To examine factors associated with fibrosis in a longterm outcomes study of Alaska Native/American Indian persons who underwent liver biopsy, and to examine the rate of fibrosis progression in persons with subsequent biopsies. METHODS: A cross-sectional analysis of the demographic, inflammatory and viral characteristics of persons undergoing liver biopsy compared individuals with early (Ishak fibrosis score of lower than 3) with those with advanced (Ishak score of 3 or greater) fibrosis. Persons who underwent two or more biopsies were analyzed for factors associated with fibrosis progression. RESULTS: Of 253 HCV RNA-positive persons who underwent at least one liver biopsy, 76 (30%) had advanced fibrosis. On multivariate analysis, a Knodell histological activity index score of 10 to 14 and an alpha-fetoprotein level of 8 ng/mL or higher were found to be independent predictors of advanced liver fibrosis (P<0.0001 for each). When surrogate markers of liver inflammation (alanine aminotransferase, aspartate aminotransferase/alanine aminotransferase ratio and alpha-fetoprotein) were removed from the model, type 2 diabetes mellitus (P=0.001), steatosis (P=0.03) and duration of HCV infection by 10-year intervals (P=0.02) were associated with advanced fibrosis. Among 52 persons who underwent two or more biopsies a mean of 6.2 years apart, the mean Ishak fibrosis score increased between biopsies (P=0.002), with progression associated with older age at initial biopsy and HCV risk factors. CONCLUSIONS: The presence of type 2 diabetes mellitus, steatosis and duration of HCV infection were independent predictors of advanced fibrosis in the present cohort, with significant fibrosis progression demonstrated in persons who underwent serial biopsies. |
Absence of evidence of xenotropic murine leukemia virus-related virus infection in persons with chronic fatigue syndrome and healthy controls in the United States
Switzer WM , Jia H , Hohn O , Zheng H , Tang S , Shankar A , Bannert N , Simmons G , Hendry RM , Falkenberg VR , Reeves WC , Heneine W . Retrovirology 2010 7 57 BACKGROUND: XMRV, a xenotropic murine leukemia virus (MuLV)-related virus, was recently identified by PCR testing in 67% of persons with chronic fatigue syndrome (CFS) and in 3.7% of healthy persons from the United States. To investigate the association of XMRV with CFS we tested blood specimens from 51 persons with CFS and 56 healthy persons from the US for evidence of XMRV infection by using serologic and molecular assays. Blinded PCR and serologic testing were performed at the US Centers for Disease Control and Prevention (CDC) and at two additional laboratories. RESULTS: Archived blood specimens were tested from persons with CFS defined by the 1994 international research case definition and matched healthy controls from Wichita, Kansas and metropolitan, urban, and rural Georgia populations. Serologic testing at CDC utilized a Western blot (WB) assay that showed excellent sensitivity to MuLV and XMRV polyclonal or monoclonal antibodies, and no reactivity on sera from 121 US blood donors or 26 HTLV-and HIV-infected sera. Plasma from 51 CFS cases and plasma from 53 controls were all WB negative. Additional blinded screening of the 51 cases and 53 controls at the Robert Koch Institute using an ELISA employing recombinant Gag and Env XMRV proteins identified weak seroreactivity in one CFS case and a healthy control, which was not confirmed by immunofluorescence. PCR testing at CDC employed a gag and a pol nested PCR assay with a detection threshold of 10 copies in 1 ug of human DNA. DNA specimens from 50 CFS patients and 56 controls and 41 US blood donors were all PCR-negative. Blinded testing by a second nested gag PCR assay at the Blood Systems Research Institute was also negative for DNA specimens from the 50 CFS cases and 56 controls. CONCLUSIONS: We did not find any evidence of infection with XMRV in our U.S. study population of CFS patients or healthy controls by using multiple molecular and serologic assays. These data do not support an association of XMRV with CFS. |
A road map for the global elimination of congenital syphilis
Kamb ML , Newman LM , Riley PL , Mark J , Hawkes SJ , Malik T , Broutet N . Obstet Gynecol Int 2010 2010 Congenital syphilis is the oldest recognized congenital infection, and continues to account for extensive global perinatal morbidity and mortality today. Serious adverse pregnancy outcomes caused by maternal syphilis infection are prevented with screening early in pregnancy and prompt treatment of women testing positive. Intramuscular penicillin, an inexpensive antibiotic on the essential medicine list of nations all over the world, effectively cures infection and prevents congenital syphilis. In fact, at a cost of $11-15 per disability adjusted life year (DALY) averted, maternal syphilis screening and treatment is among the most cost-effective public health interventions in existence. Yet implementation of this basic public health intervention is sporadic in countries with highest congenital syphilis burden. We discuss the global burden of this devastating disease, current progress and ongoing challenges for its elimination in countries with highest prevalence, and next steps in ensuring a world free of preventable perinatal deaths caused by syphilis. |
The effectiveness of patient-delivered partner therapy and chlamydial and gonococcal reinfection in San Francisco
Stephens SC , Bernstein KT , Katz MH , Philip SS , Klausner JD . Sex Transm Dis 2010 37 (8) 525-9 BACKGROUND: Patient-delivered partner therapy (PDPT) has been evaluated in randomized trials. No analysis has examined the impact of PDPT once implemented programmatically. METHODS: We examined the association between receiving PDPT and Chlamydia trachomatis and Neisseria gonorrhoeae reinfection within 1 year in patients diagnosed at San Francisco City Clinic between October 31, 2005 and March 31, 2008. Propensity score modeling was used to control for the difference between persons who did and did not receive PDPT. RESULTS: There was no significant difference between patients who received PDPT and those that did not in the crude cumulative risk for repeat infection with C. trachomatis or N. gonorrhoeae. Using propensity score analysis, the adjusted relative risk was 0.99 (0.86-1.14) for chlamydial reinfection and 0.90 (0.72-1.11) for gonococcal reinfection. Further analysis looking at men who have sex with men, men who have sex with women, and females showed no significant reductions in relative risk of reinfection for C. trachomatis or N. gonorrhoeae in these sub populations. CONCLUSIONS: Continued evaluation of PDPT on reinfection rates in real world settings as well as cost-effectiveness analyses of PDPT are needed to assess this alternative method of partner treatment. |
One in four people may develop symptomatic hip osteoarthritis in his or her lifetime
Murphy LB , Helmick CG , Schwartz TA , Renner JB , Tudor G , Koch GG , Dragomir AD , Kalsbeek WD , Luta G , Jordan JM . Osteoarthritis Cartilage 2010 18 (11) 1372-9 OBJECTIVE: To estimate the lifetime risk of symptomatic hip osteoarthritis (OA). DESIGN: We analyzed data from the Johnston County Osteoarthritis Project (a longitudinal population-based study of OA in North Carolina, United States [n=3,068]). The weighted baseline sample comprised 18% blacks and 54% women, and the mean age was 63 years (range=45-93). Symptomatic hip OA was defined as a Kellgren-Lawrence (K-L) radiographic score of ≥2 (anterior-posterior pelvis x-rays) and pain, aching or stiffness on most days, or groin pain, in the same hip. Lifetime risk, defined as the proportion who developed symptomatic hip OA in at least one hip by age 85, among people who live to age 85, was modeled using logistic regression with repeated measures (through generalized estimating equations). RESULTS: Lifetime risk of symptomatic hip OA was 25.3% (95% confidence interval [CI] = 21.3-29.3). Lifetime risk was similar by sex, race, highest educational attainment, and hip injury history. We studied lifetime risk by body mass index (BMI) in three forms: at age 18; at baseline and follow-up; and at age 18, baseline and follow-up and found no differences in estimates. CONCLUSION: The burden of symptomatic hip OA is substantial with one in four people developing this condition by age 85. The similar race-specific estimates suggest that racial disparities in total hip replacements are not attributable to differences in disease occurrence. Despite increasing evidence that obesity predicts an increased risk of both hip OA and joint replacement, we found no association between BMI and lifetime risk. |
Interrelationship of cytokines, hypothalamic-pituitary-adrenal axis hormones, and psychosocial variables in the prediction of preterm birth
Pearce BD , Grove J , Bonney EA , Bliwise N , Dudley DJ , Schendel DE , Thorsen P . Gynecol Obstet Invest 2010 70 (1) 40-6 BACKGROUND/AIMS: To examine the relationship of biological mediators (cytokines, stress hormones), psychosocial, obstetric history, and demographic factors in the early prediction of preterm birth (PTB) using a comprehensive logistic regression model incorporating diverse risk factors. METHODS: In this prospective case-control study, maternal serum biomarkers were quantified at 9-23 weeks' gestation in 60 women delivering at <37 weeks compared to 123 women delivering at term. Biomarker data were combined with maternal sociodemographic factors and stress data into regression models encompassing 22 preterm risk factors and 1st-order interactions. RESULTS: Among individual biomarkers, we found that macrophage migration inhibitory factor (MIF), interleukin-10, C-reactive protein (CRP), and tumor necrosis factor-alpha were statistically significant predictors of PTB at all cutoff levels tested (75th, 85th, and 90th percentiles). We fit multifactor models for PTB prediction at each biomarker cutoff. Our best models revealed that MIF, CRP, risk-taking behavior, and low educational attainment were consistent predictors of PTB at all biomarker cutoffs. The 75th percentile cutoff yielded the best predicting model with an area under the ROC curve of 0.808 (95% CI 0.743-0.874). CONCLUSION: Our comprehensive models highlight the prominence of behavioral risk factors for PTB and point to MIF as a possible psychobiological mediator. |
Ownership and usage of insecticide-treated bed nets after free distribution via a voucher system in two provinces of Mozambique
Macedo de Oliveira A , Wolkon A , Krishnamurthy R , Erskine M , Crenshaw DP , Roberts J , Saute F . Malar J 2010 9 (1) 222 BACKGROUND: Insecticide-treated bed nets (ITNs) are an efficacious intervention for malaria prevention. During a national immunization campaign in Mozambique, vouchers, which were to be redeemed at a later date for free ITNs, were distributed in Manica and Sofala provinces. A survey to evaluate ITN ownership and usage post-campaign was conducted. METHODS: Four districts in each province and four enumeration areas (EAs) in each district were selected using probability proportional to size. Within each EA, 32 households (HHs) were selected using a simple random sample. Interviews to assess ownership and usage were conducted in each of the selected HHs using personal digital assistants. RESULTS: Valid interviews were completed for 947 (92.5%) (440 in Manica and 507 in Sofala) of the 1,024 selected HHs. Among participating HHs, 65.0% in Manica and 63.1% in Sofala reported that at least one child under five years of age slept in the house the previous night. HH ownership of at least one bed net of any kind was 20.6% (95% confidence interval [CI]: 7.9%-43.6%) and 35.6% (95% CI: 27.8%-44.3%) pre-campaign; and 55.1% (95% CI: 43.6%-66.1%) and 59.6 (95% CI: 42.4%-74.7%) post-campaign in Manica and Sofala, respectively. Post-campaign HH ownership of at least one ITN was 50.2% (95% CI: 41.8%-58.5%) for both provinces combined. In addition, 60.3% (95% CI: 50.6%-69.2%) of children under five years of age slept under an ITN the previous night. CONCLUSIONS: This ITN distribution increased bed net ownership and usage rates. Integration of ITN distribution with immunization campaigns presents an opportunity for reaching malaria control targets and should continue to be considered. |
How late is too late? Timeliness to scheduled visits as an antiretroviral therapy adherence measure in Nairobi, Kenya and Lusaka, Zambia
Blacher RJ , Muiruri P , Njobvu L , Mutsotso W , Potter D , Ong'ech J , Mwai P , Degroot A , Zulu I , Bolu O , Stringer J , Kiarie J , Weidle PJ . AIDS Care 2010 22 (11) 1-9 Collecting self-reported data on adherence to highly active antiretroviral therapy (HAART) can be complicated by patients' reluctance to report poor adherence. The timeliness with which patients attend visits might be a useful alternative to estimate medication adherence. Among Kenyan and Zambian women receiving twice daily HAART, we examined the relationship between self-reported pill taking and timeliness attending scheduled visits. We analyzed data from 566 Kenyan and Zambian women enrolled in a prospective 48-week HAART-response study. At each scheduled clinic visit, women reported doses missed over the preceding week. Self-reported adherence was calculated by summing the total number of doses reported taken and dividing by the total number of doses asked about at the visit attended. A participant's adherence to scheduled study visits was defined as "on time" if she arrived early or within three days, "moderately late" if she was four-seven days late, and "extremely late/missed" if she was more than eight days late or missed the visit altogether. Self-reported adherence was <95% for 29 (10%) of 288 women who were late for at least one study visit vs. 3 (1%) of 278 who were never late for a study visit (odds ratios [OR] 10.3; 95% confidence intervals [95% CI] 2.9, 42.8). Fifty-one (18%) of 285 women who were ever late for a study visit experienced virologic failure vs. 32 (12%) of 278 women who were never late for a study visit (OR 1.7; 95% CI 1.01, 2.8). A multivariate logistic regression model controlling for self-reported adherence found that being extremely late for a visit was associated with virologic failure (OR 2.0; 95% CI 1.2, 3.4). Timeliness to scheduled visits was associated with self-reported adherence to HAART and with risk for virologic failure. Timeliness to scheduled clinic visits can be used as an objective proxy for self-reported adherence and ultimately for risk of virologic failure. |
Comparison of home and clinic-based HIV testing among household members of persons taking antiretroviral therapy in Uganda: results from a randomized trial
Lugada E , Levin J , Abang B , Mermin J , Mugalanzi E , Namara G , Gupta S , Grosskurth H , Jaffar S , Coutinho A , Bunnell R . J Acquir Immune Defic Syndr 2010 55 (2) 245-52 OBJECTIVE: Due to high rates of undiagnosed and untreated HIV infection in Africa, we compared HIV counseling and testing (VCT) uptake among household members of patients receiving antiretroviral therapy. METHODS: HIV-infected persons attending an AIDS clinic were randomized to a home-based or clinic-based antiretroviral therapy program including VCT for household members. Clinic arm participants were given free VCT vouchers and encouraged to invite their household members to the clinic for VCT. Home arm participants were visited, and their household members offered VCT using a 3-test rapid finger-stick testing algorithm. VCT uptake and HIV prevalence were compared. FINDINGS: Of 7184 household members, 3974 (55.3%) were female and 4798 (66.8%) were in the home arm. Home arm household members were more likely to receive VCT than those from the clinic arm (55.8% vs. 10.9%, odds ratio: 10.41, 95% confidence interval: 7.89 to 13.73; P < 0.001), although the proportion of HIV-infected household members was higher in the clinic arm (17.3% vs. 7.1%, odds ratio: 2.76, 95% confidence interval: 1.97 to 3.86, P < 0.001). HIV prevalence among all household members tested in the home arm was 56% compared with 27% in the clinic arm. Of 148 spouses of HIV-infected patients, 69 (46.6%) were uninfected. Persons aged 15-24 were less likely to test than other age groups, and in the home arm, women were more likely to test than men. CONCLUSIONS: Home-based VCT for household members of HIV-infected persons was feasible, associated with lower prevalence, higher uptake, and increased identification of HIV-infected persons than clinic-based provision. |
An augmented passive immune therapy to treat fulminant bacterial infections
Rajam G , Sampson J , Carlone GM , Ades EW . Recent Pat Antiinfect Drug Discov 2010 5 (2) 157-67 In the early 1900s, passive immunization/antibody therapy was used to treat a variety of human ailments such as hypoimmunoglobulinemia, cancer and infectious disease. The advent of antibiotic therapy had relegated this type of therapy obsolete for treatment of infectious diseases. Emergence of multi-drug resistant pathogens along with novel monoclonal antibody production techniques has rekindled the interest in passive immunization (PI). An increase in the number of monoclonal antibody patent applications in the recent past suggests a renewed commercial interest in PI. Despite these developments, antibody therapy for infectious diseases has limitations including the need for large or frequent dosages. P4, a 28-amino acid peptide is a multi-lineage cellular activator. P4, along with infectious disease (i.e. Pathogen) specific immunoglobulin, has been shown in vitro and in vivo in mice to potentiate innate immunity. This review will discuss the progress made in passive antibody therapy, the challenges still to be surmounted, and the potential expanded role of an immune-potentiating peptide (bio-molecule) in the quest to utilize and revitalize passive immunization. |
Potential loss of methionine following extended storage of newborn screening samples prepared for tandem mass spectrometry analysis
Chace DH , Luo Z , De Jesus VR , Haynes CA , Hannon WH . Clin Chim Acta 2010 411 1284-6 BACKGROUND: Methionine (Met) is a key metabolite used in the newborn screening of homocystinuria by tandem mass spectrometry (MS/MS). Recently, a loss of ion counts in both Met and its deuterium-labeled internal standard ((2)H(3)-Met) was observed by the CDC's Newborn Screening Quality Assurance Program laboratory. We report on the stability of labeled and unlabeled Met solutions and their storage in two types of 96 well microtiter plates to illustrate the potential loss of Met following storage of samples prior to MS/MS analysis. METHODS: Neat labeled and unlabeled Met standards were prepared and added (25, 50 and 100 microl) to two different types of microtiter plates, dried under nitrogen and stored for up to 168 h. All samples were reconstituted in mobile phase and analyzed as free acids for simplification of the study. RESULTS AND CONCLUSIONS: Met appears to interact significantly with polystyrene microtiter plates and to a much lesser extent with polypropylene microtiter plates. Furthermore, the loss is greatest for lower concentrations of methionine. While this loss of Met signal may be unimportant due to a presumption of equal loss of (2)H(3)-Met, a significant decline in ion signals will cause greater error in the calculation of concentration. These results suggest that polypropylene may be a better choice for Met analysis. Furthermore, storing prepared samples prior to analysis may impact the quality of the MS/MS analysis for Met and potentially other metabolites. Plates used by newborn screening laboratories should be evaluated periodically if the signal intensity for Met is reduced. |
Poxvirus complement control proteins are expressed on the cell surface through an intermolecular disulfide bridge with the viral A56 protein
Dehaven BC , Girgis NM , Xiao Y , Hudson PN , Olson VA , Damon IK , Isaacs SN . J Virol 2010 84 (21) 11245-54 The vaccinia virus (VACV) complement control protein (VCP) is an immunomodulatory protein that is both secreted from and expressed on the surface of infected cells. Surface expression of VCP occurs though an interaction with the viral transmembrane protein A56, and is dependent on a free N-terminal cysteine of VCP. Although A56 and VCP have been shown to interact in infected cells, the mechanism remains unclear. To investigate if A56 is sufficient for surface expression, we transiently expressed VCP and A56 in eukaryotic cell lines, and found that they interact on the cell surface in the absence of other viral proteins. Since A56 contains three extracellular cysteines, we hypothesized that one of the cysteines may be unpaired and could therefore form a disulfide bridge with VCP. To test this, we generated a series of A56 mutants in which each cysteine was mutated to a serine, and found that mutation of cysteine 162 abrogated VCP cell surface expression. We also tested the ability of other poxvirus complement control proteins to bind to VACV A56. While the smallpox homolog of VCP is able to bind VACV A56, the ectromelia virus (ECTV) VCP homolog is only able to bind the ECTV homolog of A56, indicating that these proteins may have co-evolved. Surface expression of poxvirus complement control proteins may have important implications in viral pathogenesis, as a virus that does not express cell surface VCP is attenuated in vivo. This suggests that surface expression of VCP may contribute to poxvirus pathogenesis. |
Cytotoxicity of eight cigarette smoke condensates in three test systems: comparisons between assays and condensates
Richter PA , Li AP , Polzin G , Roy SK . Regul Toxicol Pharmacol 2010 58 (3) 428-36 Cytotoxic properties of tobacco smoke are associated with chronic tobacco-related diseases. The cytotoxicity of tobacco smoke can be tested with short-term predictive assays. In this study, we compare 8 mainstream cigarette smoke condensates (CSCs) from commercial and experimental cigarettes in three different cytotoxicity assays with unique and overlapping endpoints. The CSCs demonstrated cytotoxicity in all assays. In the Multiple Cytotoxicity Endpoint (MCE) assay with TK-6 cells, the cigarette varieties that had the highest EC50s for reduced cell growth also showed a positive dose-response relationship for necrotic cells. In the IdMOC Multiple Cell-Type Co-culture (MCTCC) system, all CSCs reduced the viability of the cells. Low concentrations of some CSCs and nicotine had a stimulatory effect in lung microvascular endothelial cells and small airway epithelial cells. In the Neutral Dye assay (NDA), except for a 100% flue-cured tobacco CSC, there was little consistency between CSCs producing morphological evidence of moderate or greater toxicity and the CSCs with the lowest EC50s in the MCE or MCTCC assays. Overall, cigarettes made with flue-cured tobacco were the most cytotoxic across the assays. When results were expressed on a per mg of nicotine basis, lower tar cigarettes were the most cytotoxic in primary human respiratory cells. |
Work-relatedness of selected chronic medical conditions and workers' compensation utilization: National Health Interview Survey occupational health supplement data
Luckhaupt SE , Calvert GM . Am J Ind Med 2010 53 (12) 1252-63 BACKGROUND: An occupational health supplement (OHS) to the 1988 National Health Interview Survey (NHIS) bypassed many limitations of traditional occupational health surveillance systems, but the data collected about chronic work-related conditions have not yet been reported. METHODS: We calculated the prevalence and proportion of cases related to work for the aggregation of 13 chronic conditions included in the NHIS-OHS, and for 11 conditions individually. For each of nine conditions, and for the aggregation of all conditions, we also calculated the prevalence of workers' compensation claims filed. RESULTS: The overall prevalence of work-related chronic conditions was 7.5% (SE = 0.16). The work-related conditions with the highest prevalence were repeated trouble with the back/neck/spine (4.91%; SE = 0.13) and trouble hearing (1.14%; SE = 0.06). Overall, workers' compensation claims were filed for 39.0% (SE = 1.00) of work-related cases. CONCLUSIONS: The burden of work-related illnesses in the US is substantial, and the workers' compensation system is underutilized. Am. J. Ind. Med. (c) 2010 Wiley-Liss, Inc. |
Potential pulmonary effects of engineered carbon nanotubes: in vitro genotoxic effects
Sargent LM , Reynolds SH , Castranova V . Nanotoxicology 2010 4 396-408 The development of novel engineered nano-sized materials is a rapidly emerging technology with many applications in medicine and industry. In vitro and in vivo studies have suggested many deleterious effects of carbon nanotube exposure including granulomatous inflammation, release of cytosolic enzymes, pulmonary fibrosis, reactive oxygen damage, cellular atypia, DNA fragmentation, mutation and errors in chromosome number as well as mitotic spindle disruption. The physical properties of the carbon nanotubes make respiratory exposure to workers likely during the production or use of commercial products. Many of the investigations of the genotoxicity of carbon nanotubes have focused on reactive oxygen mediated DNA damage; however, the long thin tubular-shaped carbon nanotubes have a striking similarity to cellular microtubules. The similarity of carbon nanotubes to microtubules suggests a potential to interact with cellular biomolecules, such as the mitotic spindle, as well as the motor proteins that separate the chromosomes during cell division. Disruption of centrosomes and mitotic spindles would result in monopolar, tripolar, and quadrapolar divisions of chromosomes. The resulting aneuploidy is a key mechanism in the potential carcinogenicity of carbon nanotubes. |
The estimated national burden of physical ergonomic hazards among US workers
Tak S , Calvert GM . Am J Ind Med 2010 54 (5) 395-404 PURPOSE: To estimate the national burden of physical ergonomic hazards among working adults in the US. METHODS: We estimated the population prevalence of and the total number of workers who are exposed to physical ergonomic hazards, such as vibration, working in cramped space, kneeling, body bending or twisting, climbing, and repetitive motions using Occupational Information Network (O*NET) data and the Occupational Employment Statistics (OES) from the U.S. Bureau of Labor Statistics (BLS) stratified by occupation title. RESULTS: Repetitive motion was the most prevalent of all ergonomic hazards (27% of US workers are estimated to be exposed continually). Bending or twisting of the body more than half their time at work was also common, involving over 32 million US workers (25% of US workforce). Kneeling, crouching, stooping, or crawling was another ergonomic hazard that 14 million US workers perform more than half their time at work. Almost 4 million workers climb ladders, scaffolds, poles, etc. for more than half their time at work. We estimate that over 13 million workers (10% of US workforce) were exposed to cramped workspace that requires getting into awkward positions every day. Finally, about 3.5 million workers (2.7% of US workforce) were estimated to be exposed to whole body vibration every day. CONCLUSION: A large portion of the US work force is exposed to ergonomic hazards known to be associated with musculoskeletal disorders (MSDs). The occupations with the highest prevalence of each ergonomic hazard may be deserving of prompt efforts toward prevention of MSDs. Am. J. Ind. Med. (c) 2010 Wiley-Liss, Inc. |
A shifting paradigm in strengthening laboratory health systems for global health: acting now, acting collectively, but acting differently
Nkengasong JN . Am J Clin Pathol 2010 134 (3) 359-60 Improving clinical and public health laboratories should be one of the main goals of strengthening health systems, rather than a desirable afterthought. In this respect, in July 2009, several African countries, donors, the World Health Organization (WHO), and implementing partners met in Kigali, Rwanda, to launch a program for strengthening laboratory management, with the aim to accelerate national laboratory services toward accreditation in the African region. Before the 2009 meeting in Kigali, the need to strengthen laboratory networks, systems, and services in developing countries was highlighted in 2008 by several landmark events, including in January 2008, issuance of the Maputo Declaration for strengthening laboratory health systems; in April 2008, the Lyon statement on the need for developing countries to establish practical quality management systems; and in September 2008, the Yaoundé resolution issued by the WHO Regional Office for Africa (AFRO) that recognized the dilapidated state of the laboratory health systems and the need to strengthen them, as a priority, to fight multiple diseases. The recent focus on strengthening health systems and the emphasis on laboratory systems suggest that the opportunity has presented itself for the international community to act now, act collectively, but act differently to ensure sustainability of global health efforts to enhance laboratory networks and systems. |
Laboratory systems and services are critical in global health: time to end the neglect?
Nkengasong JN , Nsubuga P , Nwanyanwu O , Gershy-Damet GM , Roscigno G , Bulterys M , Schoub B , Decock KM , Birx D . Am J Clin Pathol 2010 134 (3) 368-73 The $63 billion comprehensive global health initiative (GHI) emphasizes health systems strengthening (HSS) to tackle challenges, including child and maternal health, HIV/AIDS, family planning, and neglected tropical diseases. GHI and other initiatives are critical to fighting emerging and reemerging diseases in resource-poor countries. HSS is also an increasing focus of the $49 billion program of the US President's Emergency Plan for AIDS Relief and the Global Fund to Fight AIDS, Tuberculosis and Malaria. Laboratory systems and services are often neglected in resource-poor settings, but the funding offers an opportunity to end the neglect. To sustainably strengthen national laboratory systems in resource-poor countries, the following approaches are needed: (1) developing integrative national laboratory strategic plans and policies and building systems to address multiple diseases; (2) establishing public-private partnerships; (3) ensuring effective leadership, commitment, and coordination by host governments of efforts of donors and partners; (4) establishing and/or strengthening centers of excellence and field epidemiology and laboratory training programs to meet short- and medium-term training and retention goals; and (5) establishing affordable, scalable, and effective laboratory accreditation schemes to ensure quality of laboratory tests and bridge the gap between clinicians and laboratory experts on the use of test results. |
Field experience in implementing ISO 15189 in Kisumu, Kenya
Zeh CE , Inzaule SC , Magero VO , Thomas TK , Laserson KF , Hart CE , Nkengasong JN . Am J Clin Pathol 2010 134 (3) 410-418 Quality medical laboratory services are an integral part of routine health care, medical research, and public health systems. Despite this vital role, quality laboratory services in Africa are scarce. The crucial need for expanding quality laboratory services throughout sub-Saharan Africa is especially critical because of the region's burden of disease. Fortunately, several plans from supporting international partners are underway to help strengthen laboratory infrastructure in this region. A key component of these initiatives is the enforcement of quality assurance services through accreditation by international standards such as the International Organization for Standardization (ISO) 15189. However, acquisition and maintenance of these standards are a significant challenge, especially in resource-limited settings. The most common limiting factors can include funding, government support, equipment, training opportunities, and poor procurement infrastructure. In this article, we discuss the challenges and benefits accrued in pursuing and sustaining ISO 15189 accreditation for the Kenya Medical Research Institute/Centre for Disease Control HIV-Research Laboratory in Kisumu, Kenya. |
Improving quality management systems of laboratories in developing countries: an innovative training approach to accelerate laboratory accreditation
Yao K , McKinney B , Murphy A , Rotz P , Wafula W , Sendagire H , Okui S , Nkengasong JN . Am J Clin Pathol 2010 134 (3) 401-9 The Strengthening Laboratory Management Toward Accreditation (SLMTA) program was developed to promote immediate, measurable improvement in laboratories of developing countries. The laboratory management framework, a tool that prescribes managerial job tasks, forms the basis of the hands-on, activity-based curriculum. SLMTA is implemented through multiple workshops with intervening site visits to support improvement projects. To evaluate the effectiveness of SLMTA, the laboratory accreditation checklist was developed and subsequently adopted by the World Health Organization Regional Office for Africa (WHO AFRO). The SLMTA program and the implementation model were validated through a pilot in Uganda. SLMTA yielded observable, measurable results in the laboratories and improved patient flow and turnaround time in a laboratory simulation. The laboratory staff members were empowered to improve their own laboratories by using existing resources, communicate with clinicians and hospital administrators, and advocate for system strengthening. The SLMTA program supports laboratories by improving management and building preparedness for accreditation. |
US physicians' intentions regarding impact of human papillomavirus vaccine on cervical cancer screening
Wong C , Berkowitz Z , Saraiya M , Wideroff L , Benard VB . Sex Health 2010 7 (3) 338-45 BACKGROUND: US cervical cancer screening recommendations have not changed since the human papillomavirus (HPV) vaccine introduction in 2006, but epidemiological and cost-effectiveness studies indicate that recommendations will need to change for fully vaccinated women. We evaluated physician intentions regarding HPV vaccine's impact on future screening. METHODS: A nationally representative sample of 1212 primary care physicians was surveyed in 2006-2007 (response rate: 67.5%). Our study included 1114 physicians who provided Pap testing. Questions covered Pap test screening practices and intentions regarding HPV vaccine's impact on screening. Distribution differences were assessed using chi(2) statistics; multivariate analyses were performed. RESULTS: Overall, 40.7% (95% confidence interval (CI): 37.6-43.8%) of physicians agreed that the HPV vaccine will affect screening initiation, and 38.2% (35.0-41.5%) agreed that vaccination will affect screening frequency. Significant differences in responses were found by specialty; internists were more likely to agree that vaccination would impact screening than other specialties. Belief in the effectiveness of new screening technologies was associated with intention to change screening initiation (odds ratio (OR) = 1.66 (1.20-2.31)) and frequency (OR = 1.99 (1.40-2.83)). Adherence to current Pap test screening interval guidelines was associated with intention to change screening frequency (OR = 1.39 (1.01-1.91)). CONCLUSIONS: Many providers anticipate adjusting screening for vaccinated women, but a significant group believes nothing will change or are unsure. The present study provides important baseline data on intentions in the period preceding widespread vaccine diffusion and may help explain current and future trends in practice patterns. |
Investigation of relationships between urinary biomarkers of phytoestrogens, phthalates, and phenols and pubertal stages in girls
Wolff MS , Teitelbaum SL , Pinney SM , Windham G , Liao L , Biro F , Kushi LH , Erdmann C , Hiatt RA , Rybak ME , Calafat AM . Environ Health Perspect 2010 118 (7) 1039-46 BACKGROUND: Hormonally active environmental agents may alter the course of pubertal development in girls, which is controlled by steroids and gonadotropins. OBJECTIVES: We investigated associations of concurrent exposures from three chemical classes (phenols, phthalates, and phytoestrogens) with pubertal stages in a multiethnic longitudinal study of 1,151 girls from New York City, New York, greater Cincinnati, Ohio, and northern California who were 6-8 years of age at enrollment (2004-2007). METHODS: We measured urinary exposure biomarkers at visit 1 and examined associations with breast and pubic hair development (present or absent, assessed 1 year later) using multivariate adjusted prevalence ratios (PR) and 95% confidence intervals (CIs). Modification of biomarker associations by age-specific body mass index percentile (BMI%) was investigated, because adipose tissue is a source of peripubertal hormones. RESULTS: Breast development was present in 30% of girls, and 22% had pubic hair. High-molecular-weight phthalate (high MWP) metabolites were weakly associated with pubic hair development [adjusted PR, 0.94 (95% CI, 0.88-1.00), fifth vs. first quintile]. Small inverse associations were seen for daidzein with breast stage and for triclosan and high MWP with pubic hair stage; a positive trend was observed for low-molecular-weight phthalate biomarkers with breast and pubic hair development. Enterolactone attenuated BMI associations with breast development. In the first enterolactone quintile, for the association of high BMI with any development, the PR was 1.34 (95% CI, 1.23-1.45 vs. low BMI). There was no BMI association in the fifth, highest quintile of enterolactone. CONCLUSIONS: Weak hormonally active xenobiotic agents investigated in this study had small associations with pubertal development, mainly among those agents detected at highest concentrations. |
Contraceptive sterilization use among married men in the United States: results from the male sample of the National Survey of Family Growth
Anderson JE , Warner L , Jamieson DJ , Kissin DM , Nangia AK , Macaluso M . Contraception 2010 82 (3) 230-5 BACKGROUND: Surgical sterilization has many advantages. Previous information on prevalence and correlates was based on surveys of women. STUDY DESIGN: We estimated the prevalence of vasectomy and tubal ligation of partners for male participants in the 2002 National Survey of Family Growth, a nationally representative survey of US residents aged 15-44 years. We identified factors associated with sterilizations using bivariate and multivariate techniques. RESULTS: The findings revealed that 13.3% of married men reported having had a vasectomy and 13.8% reported tubal sterilization in their partners. Vasectomy increased with older age and greater number of biological children, non-Hispanic white ethnicity, having ever gone to a family planning clinic. Tubal sterilization use was more likely among men who had not attended college, those of older age and those with live births. DISCUSSION: One in eight married men reported having vasectomies. Men who rely on vasectomies have a somewhat different profile than those whose partners have had tubal sterilizations. |
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