Case-case analyses of cryptosporidiosis and giardiasis using routine national surveillance data in the United States - 2005-2015.

Understanding endemic infectious disease risk factors through traditional epidemiological tools is challenging. Population-based case-control studies are costly and time-consuming. A case-case analyses using surveillance data addresses these limitations by using resources more efficiently. We conducted a case-case analyses using routine surveillance data reported by 16 U.S. states (2005-2015), wherein reported cases of salmonellosis were used as a comparison group to identify exposure associations with reported cases of cryptosporidiosis and giardiasis. Odds ratios adjusted for age and reporting state (aOR) and 95% confidence intervals (95% CI) were calculated. A total of 10 704 cryptosporidiosis cases, 17 544 giardiasis cases, and 106 351 salmonellosis cases were included in this analyses. When compared with cases of salmonellosis, exposure to treated recreational water (aOR 4.7, 95% CI 4.3-5.0) and livestock (aOR: 3.2; 95% CI: 2.9-3.5) were significantly associated with cryptosporidiosis and exposure to untreated drinking (aOR 4.1, 95% CI 3.6-4.7) and recreational water (aOR 4.1, 95% CI 3.7-4.5) were associated with giardiasis. Our analyses shows that routine surveillance data with standardised exposure information can be used to identify associations of interest for cryptosporidiosis and giardiasis.

Discordance in latent tuberculosis (TB) test results in patients with end-stage renal disease.

OBJECTIVES: This natural experiment was designed to assess the impact of exposure to an active case of tuberculosis (TB) on a group of immunosuppressed individuals, with end-stage renal disease over an extended follow-up. STUDY DESIGN: Close contacts of people with sputum smear-positive Mycobacterium tuberculosis are at high risk of infection, particularly immunosuppressed individuals. An infectious TB healthcare worker worked in a renal dialysis unit for a month before diagnosis, with 104 renal dialysis patients, was exposed for ≥8 h. METHODS: Patients were informed and invited for screening 8-10 weeks postexposure. They either underwent standard two-step assessment with tuberculin skin test (TST) and QuantiFERON®-TB Gold (Cellestis GmbH; QFN) interferon-gamma release assay (IGRA) or after consent, enrolled in a study where these two tests were performed simultaneously with T-SPOT®-TB (Oxford Immunotec Ltd; TSPOT). Patients within the study were followed up for 2 years from exposure, with QFN and TSPOT repeated at months 3 and 6 from the first testing. RESULTS: Of 104 exposed individuals, 75 enrolled in the study. There was a high degree of discordance among QFN, TSPOT and TST. This was seen at both the first time point and also over time in subjects who were retested. No patients had active TB at the baseline testing. None received treatment for latent TB infection. Over the following 2 years, no one developed TB disease. CONCLUSION: This study suggests that there is a low risk of progression to active TB in low-incidence countries even in high-risk groups. This plus the degree of the test result discordance emphasises the complexities of managing TB in such settings as it is unclear which of these tests, if any, provides the best diagnostic accuracy.

Risk factors for sporadic Giardia infection in the USA: a case-control study in Colorado and Minnesota.

Giardia duodenalis is the most common intestinal parasite of humans in the USA, but the risk factors for sporadic (non-outbreak) giardiasis are not well described. The Centers for Disease Control and Prevention and the Colorado and Minnesota public health departments conducted a case-control study to assess risk factors for sporadic giardiasis in the USA. Cases (N = 199) were patients with non-outbreak-associated laboratory-confirmed Giardia infection in Colorado and Minnesota, and controls (N = 381) were matched by age and site. Identified risk factors included international travel (aOR = 13.9; 95% CI 4.9-39.8), drinking water from a river, lake, stream, or spring (aOR = 6.5; 95% CI 2.0-20.6), swimming in a natural body of water (aOR = 3.3; 95% CI 1.5-7.0), male-male sexual behaviour (aOR = 45.7; 95% CI 5.8-362.0), having contact with children in diapers (aOR = 1.6; 95% CI 1.01-2.6), taking antibiotics (aOR = 2.5; 95% CI 1.2-5.0) and having a chronic gastrointestinal condition (aOR = 1.8; 95% CI 1.1-3.0). Eating raw produce was inversely associated with infection (aOR = 0.2; 95% CI 0.1-0.7). Our results highlight the diversity of risk factors for sporadic giardiasis and the importance of non-international-travel-associated risk factors, particularly those involving person-to-person transmission. Prevention measures should focus on reducing risks associated with diaper handling, sexual contact, swimming in untreated water, and drinking untreated water.

A prospective cohort study assessing the appearance of retrieved aesthetic orthodontic archwires.

OBJECTIVES: To investigate the appearance of three esthetic nickel titanium (NiTi) wires after 6 weeks of intra-oral cycling and to determine the association between objective and subjective measures of esthetics. SETTING AND SAMPLE POPULATION: A prospective cohort study was undertaken involving participants undergoing upper fixed orthodontic appliance treatment with ceramic brackets. MATERIALS AND METHODS: Fifty participants were assigned to one of three groups of NiTi esthetic wires (American Orthodontics Ever White™, Forestadent Biocosmetic™ and GAC High Aesthetic™), with wires retrieved after 6 weeks in situ. Participants completed a bespoke questionnaire exploring perceptions of wire esthetics. Objective measurement of coating loss was undertaken using a custom arch wire jig. RESULTS: American Orthodontics Ever White™ had the greatest mean coating loss (50.7%) followed by Forestadent Biocosmetic™ (6%), with GAC High Aesthetic TM undergoing minimal loss (0.07%) (P < .001). The majority of coating loss with the American Orthodontics Ever White™ wires arose in the anterior region while Forestadent Biocosmetic™ wires and GAC High Aesthetic™ wires exhibited coating loss posteriorly (P < .001). These findings were reflected in the subjective assessment with a negative correlation found between coating loss and final Visual Analogue Scale scores (P < .001). CONCLUSIONS: Considerable esthetic variation between arch wires following 6 weeks of intraoral cycling was identified in this prospective cohort study. Intraoral cycling has a negative impact on participant perception of arch wire esthetics, and objective and subjective assessment of wire esthetics appears to be consistent.

Soft Tissue Atrophy Related to Corticosteroid Injection: Review of the Literature and Implications for Hand Surgeons.

Corticosteroid injections (CIs) are frequently used by hand surgeons to treat a wide range of pathology including de Quervain tenosynovitis and lateral epicondylitis. Although generally viewed as a benign modality, and a way to potentially avoid or postpone surgical intervention, common complications from CI should be considered and discussed with patients before the procedure. One such complication is local soft tissue atrophy and hypopigmentation after injection. We discuss the incidence of soft tissue-related adverse effects from CI, the pathophysiology and influence of different steroid preparations on soft tissues, and potential treatment options once atrophy has occurred.

A genetic risk score that includes common type 2 diabetes risk variants is associated with gestational diabetes.

OBJECTIVE: Gestational diabetes (GDM) is characterized by maternal glucose intolerance that manifests during pregnancy. Because GDM resembles type 2 diabetes (T2DM), shared genetic predisposition is likely but has not been established. We tested the hypothesis that a genetic risk score (GRS) that included variants known to be associated with T2DM is associated with GDM. STUDY DESIGN: We conducted a case-control study using the Vanderbilt Medical Center biobank (BioVU) and calculated a simple-count GRS using 34 variants previously associated with T2DM or fasting glucose in the general population, or with GDM or glucose intolerance in pregnancy. We assessed the association of the GRS with GDM adjusting for maternal age, parity, and body mass index (BMI) and calculated the area under the curve for the receiver-operating characteristic curve (c-statistic). STUDY POPULATION: Among Caucasian women, we identified 458 cases of GDM and 1538 pregnant controls with normal glucose tolerance. RESULTS: Cases of GDM had a higher number of risk alleles compared to controls (38.9±4.0 vs 37.4±4.0 risk alleles, P=1.6×10-11 ). The GRS was significantly associated with GDM; the adjusted odds ratio associated with each additional risk allele was 1.10 (95% CI: 1.07-1.13, P=6×10-11 ). Clinical variables predicted the risk of GDM (c-statistic 0.67, 95% CI: 0.64-0.70), and adding the GRS modestly improved prediction (0.70, 95% CI: 0.67-0.73). CONCLUSIONS: Among Caucasian women, a GRS that included common T2DM genetic risk variants was associated with increased risk of GDM but showed limited utility in the identification of GDM cases.

Association between Giardia and arthritis or joint pain in a large health insurance cohort: could it be reactive arthritis?

This study aimed to assess the association between giardiasis and subsequent development of arthritis or joint pain using a retrospective cohort of individuals from a large administrative claims database in the United States. Using 2006-2010 data from MarketScan Commercial Claims and Encounters, we conducted a retrospective cohort study in people with an ICD-9-CM code for giardiasis (n = 3301) and persons without giardiasis (n = 14 612) individually matched on age, sex, and enrolment length. We used conditional logistic regression to model the association between giardiasis and arthritis or joint pain documented in the 6 months following initial giardiasis diagnosis or index date for matched controls. After adjusting for healthcare utilization rate, giardiasis was associated with a 51% increase in claims for arthritis or joint pain (odds ratio 1·51, 95% confidence interval 1·26-1·80). In age- and sex-stratified adjusted analyses, the association remained significant across all subgroups (age 0-19 years, age 20-64 years, males, and females). Findings from this study lend epidemiological support for the association between giardiasis and subsequent development of arthritis. Reactive arthritis might occur more frequently than has been reported in the literature. Further research is necessary to determine the mechanisms by which giardiasis could lead to arthritis.

Prevalence and direct costs of emergency department visits and hospitalizations for selected diseases that can be transmitted by water, United States.

National emergency department (ED) visit prevalence and costs for selected diseases that can be transmitted by water were estimated using large healthcare databases (acute otitis externa, campylobacteriosis, cryptosporidiosis, Escherichia coli infection, free-living ameba infection, giardiasis, hepatitis A virus (HAV) infection, Legionnaires' disease, nontuberculous mycobacterial (NTM) infection, Pseudomonas-related pneumonia or septicemia, salmonellosis, shigellosis, and vibriosis or cholera). An estimated 477,000 annual ED visits (95% CI: 459,000-494,000) were documented, with 21% (n = 101,000, 95% CI: 97,000-105,000) resulting in immediate hospital admission. The remaining 376,000 annual treat-and-release ED visits (95% CI: 361,000-390,000) resulted in $194 million in annual direct costs. Most treat-and-release ED visits (97%) and costs ($178 million/year) were associated with acute otitis externa. HAV ($5.5 million), NTM ($2.3 million), and salmonellosis ($2.2 million) were associated with next highest total costs. Cryptosporidiosis ($2,035), campylobacteriosis ($1,783), and NTM ($1,709) had the highest mean costs per treat-and-release ED visit. Overall, the annual hospitalization and treat-and-release ED visit costs associated with the selected diseases totaled $3.8 billion. As most of these diseases are not solely transmitted by water, an attribution process is needed as a next step to determine the proportion of these visits and costs attributable to waterborne transmission.

Mortality from selected diseases that can be transmitted by water - United States, 2003-2009.

Diseases spread by water are caused by fecal-oral, contact, inhalation, or other routes, resulting in illnesses affecting multiple body systems. We selected 13 pathogens or syndromes implicated in waterborne disease outbreaks or other well-documented waterborne transmission (acute otitis externa, Campylobacter, Cryptosporidium, Escherichia coli (E. coli), free-living ameba, Giardia, Hepatitis A virus, Legionella (Legionnaires' disease), nontuberculous mycobacteria (NTM), Pseudomonas-related pneumonia or septicemia, Salmonella, Shigella, and Vibrio). We documented annual numbers of deaths in the United States associated with these infections using a combination of death certificate data, nationally representative hospital discharge data, and disease-specific surveillance systems (2003-2009). We documented 6,939 annual total deaths associated with the 13 infections; of these, 493 (7%) were caused by seven pathogens transmitted by the fecal-oral route. A total of 6,301 deaths (91%) were associated with infections from Pseudomonas, NTM, and Legionella, environmental pathogens that grow in water system biofilms. Biofilm-associated pathogens can cause illness following inhalation of aerosols or contact with contaminated water. These findings suggest that most mortality from these 13 selected infections in the United States does not result from classical fecal-oral transmission but rather from other transmission routes.

Evolving epidemiology of reported cryptosporidiosis cases in the United States, 1995-2012.

Cryptosporidium is the leading aetiology of waterborne disease outbreaks in the United States. This report briefly describes the temporal and geographical distribution of US cryptosporidiosis cases and presents analyses of cryptosporidiosis case data reported in the United States for 1995-2012. The Cochran-Armitage test was used to assess changes in the proportions of cases by case status (confirmed vs. non-confirmed), sex, race, and ethnicity over the study period. Negative binomial regression models were used to estimate rate ratios (RR) and 95% confidence intervals (CI) for comparing rates across three time periods (1995-2004, 2005-2008, 2009-2012). The proportion of confirmed cases significantly decreased (P < 0·0001), and a crossover from male to female predominance in case-patients occurred (P < 0·0001). Overall, compared to 1995-2004, rates were higher in 2005-2008 (RR 2·92, 95% CI 2·08-4·09) and 2009-2012 (RR 2·66, 95% CI 1·90-3·73). However, rate changes from 2005-2008 to 2009-2012 varied by age group (P interaction < 0·0001): 0-14 years (RR 0·55, 95% CI 0·42-0·71), 15-44 years (RR 0·99, 95% CI 0·82-1·19), 45-64 years (RR 1·47, 95% CI 1·21-1·79) and ⩾65 years (RR 2·18, 95% CI 1·46-3·25). The evolving epidemiology of cryptosporidiosis necessitates further identification of risk factors in population subgroups. Adding systematic molecular typing of Cryptosporidium specimens to US national cryptosporidiosis surveillance would help further identify risk factors and markedly expand understanding of cryptosporidiosis epidemiology in the United States.

Effects of light sources and intensity on broilers grown to heavy weights. Part 1: Growth performance, carcass characteristics, and welfare indices.

This study investigated the effects of light sources and light intensity on growth performance, carcass characteristics, and welfare indices of heavy broilers (>3.0 kg) in 4 trials with 2 replications per trial. A total of 960 one-day-old Ross×Ross 708 chicks (30 males/30 females/room) were randomly distributed into 16 environmentally controlled rooms at 50% RH. A 4×2 factorial treatment structure evaluated 4 light sources (incandescent [ICD, standard], compact fluorescent [CFL], neutral light emitting diode [Neutral-LED], and cool poultry specific filtered LED [Cool-PSF-LED]) and 2 levels (5 lx, 20 lx) of light intensities. Each of the 4 light sources was paired with one of the 2 light intensities. Birds were fed the same diet with a 4-phase feeding program (starter, grower, finisher, and withdrawal). Feed and water were provided ad libitum. Birds and feed were weighed on one, 14, 21, 28, 42, and 56 d of age for growth performance. All mortality was recorded daily and feed conversion was adjusted for mortality. Immune response was determined on d 28 to d 35, whereas other welfare indices were performed on d 42 and 49, respectively. At d 56 of each trial, 20 (10 males and 10 females) birds from each room were processed to determine weights and yields. The BW, BW gain, live weight, and carcass weights of birds reared under Cool-PSF-LED were different (P≤0.05) in comparison to birds reared under ICD. However, FI, FCR, and mortality were not affected by treatments. There was no effect of treatments on fat or breast and tender weights and yields. In addition, there was no effect of treatments on ocular development, immune response, and other welfare indices, suggesting that the light sources evaluated did not compromise welfare of heavy broilers. It was concluded that the 3 light sources evaluated in this study may be suitable for replacement of ICD light source in poultry facilities to reduce energy cost and optimize production efficiency.

Effects of color temperatures (Kelvin) of LED bulbs on blood physiological variables of broilers grown to heavy weights.

Light-emitting diode (LED) lighting is being used in the poultry industry to reduce energy usage in broiler production facilities. However, limited data are available comparing efficacy of different spectral distribution of LED bulbs on blood physiological variables of broilers grown to heavy weights (>3 kg). The present study evaluated the effects of color temperature (Kelvin) of LED bulbs on blood physiological variables of heavy broilers in 2 trials with 4 replicates/trial. The study was a randomized complete block design. Four light treatments consisted of 3 LED light bulbs [2,700 K, (Warm-LED); 5,000 K, (Cool-LED-#1); 5,000 K, (Cool-LED-#2)] and incandescent light (ICD, standard) from 1 to 56 d age. A total of 960 1-day-old Ross × Ross 708 chicks (30 males/room 30 females/room) were equally and randomly distributed among 16 environmentally controlled rooms at 50% RH. Each of the 4 treatments was represented by 4 rooms. Feed and water were provided ad libitum. All treatment groups were provided the same diet. Venous blood samples were collected on d 21, 28, 42, and 56 for immediate analysis of selected physiological variables and plasma collection. In comparison with ICD, Cool-LED-#1 had greater (P < 0.05) effects on pH, partial pressure of CO2(pCO2), partial pressure of O2(pO2), saturated O2(sO2), and K⁺. However, all these acid-base changes remained within the normal venous acid-base homeostasis and physiological ranges. In addition, no effect of treatments was observed on HCO(3)(-), hematocrit (Hct), hemoglobin (Hb), Na⁺, Ca²âº, Cl⁻, mean corpuscular hemoglobin concentration (McHc), osmolality, and anion gap. Moreover, blood glucose concentrations were not affected by treatments. This study shows that the 3 LED light bulbs evaluated in this study may be suitable for replacement of ICD light sources in commercial poultry facilities to reduce energy cost and optimize production efficiency without inducing physiological stress on broilers grown to heavy weights.

Effects of color temperatures (kelvin) of LED bulbs on growth performance, carcass characteristics, and ocular development indices of broilers grown to heavy weights.

Limited data are available for comparing light-emitting diode (LED) bulbs that are currently available in commercial broiler production facilities. We evaluated the effects of color temperatures (kelvin) of LED bulbs on growth performance, carcass characteristics, and ocular development indices of broilers grown to heavy weights (>3.0 kg). The experiment had a randomized complete block design. Four treatments consisted of 3 LED light bulbs (2,700 [warm LED]; 5,000 [cool LED 1]; and 5,000 K [cool LED 2]) and incandescent light (2,010 K [ICD], standard) from day zero to 56 d of age. A total of 960 Ross×Ross 708 day-old chicks were equally and randomly distributed into 16 environmentally controlled rooms at 50% RH (30 males and 30 females/room). Thus, each of the 4 treatments was represented by 4 rooms (4 replicates) per trial. Feed and water were provided ad libitum. All birds were fed the same diet. Ocular specimens were collected on d 42 for development and histopathologic examination. Blood samples were collected on d 21, 28, 42, and 56 to determine plasma corticosterone. On d 56, twenty birds from each room (10 males and 10 females) were processed to determine weights and yields. The BW and BW gain (BWG), live weight, and carcass weights of birds reared under cool LED 1 were different in comparison to birds reared under ICD (P<0.05). However, feed intake (FI), feed conversion ratio (FCR), and mortality were not affected by treatments. The treatments did not affect fat, breast and tender weights, and yields. In addition, ocular development indices and plasma corticosterone concentrations were not affected by treatments, suggesting the LED light bulbs we evaluated did not compromise the welfare of the birds. It was concluded that cool LED 1 may be a better potential replacement light source in comparison to ICD on performance, but it may be equal when compared to other LED light sources examined in this study.

The impact of deposition site on vaccination efficiency of a live bacterial poultry vaccine.

Vaccines are utilized within the poultry industry to minimize disease-associated losses and spray vaccination is a commonly utilized means for the mass application of poultry vaccines. During this process, vaccine-laden particles are deposited upon target areas (e.g., eyes, nares, and oral cavity) resulting in the direct internalization of the vaccine. However, particles are also deposited on nontarget areas such as the exterior of the subject and its surrounding environment. To better determine the fate of particles deposited upon nontarget areas and the impact of deposition site on the efficiency of vaccine application, a live bacterial poultry vaccine (AviPro(®) MG F) was applied via spray using a spray cabinet with a slotted partition allowing for head-only, body-only, and whole-bird spray application. At 11 wk age, Hy-Line(®) W-36 pullets (n = 280) were allocated equally among 7 treatments including: nonvaccinated controls, pullets spray-vaccinated at the manufacturer's recommended dose (1X) in a site-specific manner (head-only, body-only, and whole-bird), pullets spray-vaccinated at 5X the recommended level (body-only), pullets vaccinated by manual eye-drop application (1X), and pullets eye-drop vaccinated at a level approximating that achieved during the spray vaccination process (1/700X). At 6 to 7 wk postvaccination, vaccination efficiency was assessed via serological-based assays [serum plate agglutination (SPA) and ELISA] and the detection of vaccine-derived in vivo populations. Results indicate an additive contribution of the vaccine deposited on the body to the overall vaccination efficiency of this live bacterial live poultry vaccine.

Effects of genetic strain and light intensity on blood physiological variables of broilers grown to heavy weights.

The effects of genetic strain, light intensity, and their interaction were examined on blood physiological variables of broilers maintained in environmentally controlled rooms in each of 5 trials. The study consisted of a 2 × 5 factorial arranged in a randomized complete block design with 10 treatments of 2 strains (Ross × Ross 308 and 708) and exposure to 5 light intensities (25, 10, 5, 2.5, and 0.2 lx) with chicks equally and randomly distributed at 1 d of age. The 5 light intensities were randomly assigned from 22 to 56 d of age. Feed and water were provided ad libitum. Venous blood samples were collected on d 21 (base line), 28, 42, and 56 of age. Main effects indicate that Ross × Ross 308 significantly (P ≤ 0.05) increased BW, partial pressure of CO2, Ca(2+), Na(+), Cl(-), and thyroxine, along with significantly (P ≤ 0.05) reduced pH level, partial pressure of O2, HCO3(-), and triiodothyronine in comparison with Ross × Ross 708. No main effect of light intensity was observed on all examined variables. In addition, no significant main effects were observed for strain, light intensity, or their interaction on saturated O2, hematocrit, hemoglobin, K(+), mean corpuscular hemoglobin concentration, glucose, osmolality, and anion gap. Physiologically, although Ross × Ross 308 had a significantly increased BW in comparison with Ross × Ross 708, Ross × Ross 708 showed a significant (P ≤ 0.05) increase in partial pressure of O2 and triiodothyronine along with lower blood partial pressure of CO2 and thyroxine. The results of this study supplement current knowledge of physiological response to differing lighting levels and may be used to establish the normal blood values for commercial broilers grown to heavy weights. Plasma corticosterone was not affected by either treatments or strain, indicating that the treatments did not induce physiological stress in broilers.

Effects of strain and light intensity on growth performance and carcass characteristics of broilers grown to heavy weights.

Effects of genetic strain and light intensity on growth performance and carcass characteristics of broilers grown to heavy weights were investigated. The experimental design was a randomized complete block design. Treatment structure was a 2 × 5 factorial arrangement with the main factors being strain (Ross × Ross 308, Ross × Ross 708) and light intensity (25, 10, 5, 2.5, and 0.2 lx) with trial as replicates. In each of the 5 trials, chicks of 2 different strains of the same commercial hatchery were equally and randomly distributed into 10 environmentally controlled rooms (5 rooms/strain) at 1 d of age at 50% RH. Each room was randomly assigned 1 of 5 light intensities from 22 to 56 d of age. Feed and water were provided ad libitum. Birds and feed were weighed on 0, 14, 28, 42, and 56 d of age for growth performance. Humoral immune response was determined on d 28, whereas ocular and blood samples were performed on d 42 and 55, respectively. On d 56, 20 (10 males and 10 females) birds/strain from each room were processed to determine weights and yields. Genetic strain was significant (P ≤ 0.05) for most of the examined variables, where Ross × Ross 308 had better growth performance and meat yield in comparison with Ross × Ross 708. Although, there was no main effect of light intensity on growth performance and meat yield, results indicated that birds under 10 and 5 lx intensities showed slightly better growth performance and meat yield compared with birds under 25, 2.5, and 0.2 lx in both strains. There was no effect of strain and light intensity on ocular indices, immune response, plasma corticosterone levels, and mortality. This study shows the positive influence on profits to commercial poultry facilities that are using a low lighting environment to reduce energy cost, optimize feed conversion, and maximize production without compromising the welfare of the broilers.

Gas-phase CO2 subtraction for improved measurements of the organic aerosol mass concentration and oxidation degree by an aerosol mass spectrometer.

The Aerodyne aerosol mass spectrometer (AMS) has been widely used for real-time characterization of the size-resolved chemical composition of sub-micrometer aerosol particles. The first step in AMS sampling is the pre-concentration of aerosols while stripping away the gas-phase components, which contributes to the high sensitivity of this instrument. The strength of the instrument lies in particle phase measurement; however, ion signals generated from gas-phase species can influence the interpretation of the particle-phase chemistry data. Here, we present methods for subtracting the varying contributions of gas-phase carbon dioxide (CO2) in the AMS spectra of aerosol particles, which is critical for determining the mass concentration and oxygen-to-carbon (O/C) ratio of organic aerosol. This report gives details on the gaseous CO2 subtraction analysis performed on a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) data set acquired from sampling of fresh and diluted vehicle emissions. Three different methods were used: (1) collocated continuous gas-phase CO2 measurement coupled with periodic filter tests consisting of sampling the same particle-free air by the AMS and the CO2 analyzer, (2) positive matrix factorization (PMF) analysis to separate the gas- and particle-phase signals of CO2(+) at m/z 44, and (3) use of the particle time-of-flight (PTOF) size-resolved chemical information for separation of gas- and particle-phase signals at m/z 44. Our results indicate that these three different approaches yield internally consistent values for the gas/particle apportionment of m/z 44, but methods 2 and 3 require certain conditions to be met to yield reliable results. The methods presented are applicable to any situation where gas-phase components may influence the PM signal of interest.

Interactive effects of photoperiod and light intensity on blood physiological and biochemical reactions of broilers grown to heavy weights.

The effects of photoperiod, light intensity, and their interaction on blood acid-base balance, metabolites, and electrolytes in broiler chickens under environmentally controlled conditions were examined in 2 trials. A 3 × 3 factorial experiment in a randomized complete block design was used in this study. In each trial, all treatment groups were provided 23L:1D with 20 lx of intensity from placement to 7 d, and then subjected to the treatments. The 9 treatments consisted of 3 photoperiods [long/continuous (23L:1D) from d 8 to 56, regular/intermittent (2L:2D), and short/nonintermittent (8L:16D) from d 8 to 48 and 23L:1D from d 49 to 56, respectively] and exposure to 3 light intensities (10, 5.0, and 0.5 lx) from d 8 through d 56 at 50% RH. Feed and water were provided ad libitum. Venous blood samples were collected on d 7, 14, 28, 42, and 56. Main effects indicated that short/nonintermittent photoperiod significantly (P < 0.05) reduced BW, pH, partial pressure of O2, saturated O2, Na(+), K(+), Ca(2+), Cl(-), osmolality, triiodothyronine (T3), and total protein along with significantly (P < 0.05) elevated partial pressure of CO2, hematocrit, hemoglobin, and lactate concentrations. In addition, there were no effects of photoperiod on HCO3(-), glucose, anion gap, and thyroxine (T4). Plasma corticosterone was not affected by photoperiod, light intensity, or their interaction. There was no effect of light intensity on most of the blood variables examined. Acid-base regulation during photoperiod and light intensity exposure did not deteriorate despite a lower pH and higher partial pressure of CO2 with normal HCO3(-). These results indicate that continuous exposure of broiler chickens to varying light intensities had a minor effect on blood physiological variables, whereas the short photoperiod markedly affected most blood physiological variables without inducing physiological stress in broilers.

Impact of fowlpox-vectored Mycoplasma gallisepticum vaccine Vectormune FP MG on layer hen egg production and egg quality parameters.

This study was conducted to determine the impact of vaccination with Vectormune FP MG on egg production and egg quality characteristics of Single Comb White Leghorn hens. Due to questions of the efficacy of this vaccine in preventing Mycoplasma gallisepticum-mediated pathology, the ability of this vaccine to protect against postproduction-peak egg losses associated with F-strain M. gallisepticum (FMG) vaccination was also investigated. Vaccination with Vectormune FP MG did not result in any significant change in egg production or egg quality parameters compared with control (unvaccinated) hens. Subsequent revaccination with FMG at 45 wk of age (woa) yielded no impact on egg production or egg quality parameters of Vectormune FP MG vaccinated hens, unlike prior results for postproduction-peak vaccination of M. gallisepticum-clean hens with FMG, which exhibited a drop in egg production of approximately 6%. No difference in egg size distribution was observed for any of the treatment groups before or after FMG revaccination. These results suggest that hens can be safely vaccinated with Vectormune FP MG as pullets and can be revaccinated with a live M. gallisepticum vaccine such as FMG at a later date with no deleterious effects on egg production or egg or eggshell quality parameters.

A de novo pathological point mutation at the 21-hydroxylase locus: implications for gene conversion in the human genome.

More than two hundred characterized 21-hydroxylase deficiency alleles appear to result exclusively from sequence exchanges involving the 21-hydroxylase gene (CYP21B) and a closely related pseudogene (CYP21A). Gene conversion-like events have also been reported in many other human gene clusters, but in the absence of a de novo mutation, the alternative explanation of a multiple recombination is possible. We now report a de novo pathological mutation at the 21-hydroxylase locus. DNA sequence analysis suggests that the mutation arose by a microconversion event involving exchange of up to 390 nucleotides between maternal CYP21A and CYP21B genes. This putative de novo gene conversion event appears to be the first characterized in humans.