PBPK/PD assessment for Parkinson's disease risk posed by airborne pesticide paraquat exposure

Exposure to several specific pesticides has led to an increase of Parkinson's disease (PD) risk. However, it is difficult to quantify the PD population risk related to certain pesticides in regions where environmental exposure data are scarce. Furthermore, the time trend of the prevalence and incidence of PD embedded in the background relationship between PD risk and pesticide exposures has not been well characterized. It has been convincingly identified that a key pesticide associated significantly with an increased risk trend of PD is paraquat (PQ). Here, we present a novel, probabilistic population-based exposure-response approach to quantify the contribution from PQ exposure to prevalence risk of PD. We found that the largest PQ exposure contributions occurred in its positive trend during 2004-2011, with the PQ contributing nearly 21 and 24%, respectively, to the PD prevalence rates among the age groups of 70-79 and ≥ 80 years in Taiwan. We also employed the present population risk model to predict the PQ-induced PD prevalence based on the projected rates of increase in PQ exposure associated with age-specific population. The predicted outcome can be used as an early warning signal for public health authorities. We suggest that a mechanistic understanding of the contribution of a specific pesticide exposure to PD risk trends is crucial to enhance our insights into the perspective on the impacts of environmental exposure on the neurodegenerative diseases.

[Retroperitoneal laparoscopic debridement therapy for infected severe acute pancreatitis]

Objective: To investigate the feasibility and availability of retroperitoneal laparoscopic debridement therapy for patients with infected severe acute pancreatitis. Methods: Clinical data of 6 patients with severe acute pancreatitis who underwent retroperitoneal laparoscopic necrotic tissue debridement therapy in the Severe Acute Pancreatitis Center of Sir Run Run Hospital between August 2014 and October 2015 was retrospectively analyzed. The laparoscopic instruments and sponge forceps were used to remove necrotic tissue under retroperitoneal space, and double-cavity drainage tube was left for continuous washing. The perioperative indicators were collected and analyzed. Results: Two of six patients underwent two surgeries, and the others underwent one surgery, with an average operation time of (220.0±58.3) minutes and a mean hospital stay time of 62.6 days (35-117 days). One patient underwent re-operation after 33 days because of intraperitoneal hemorrhage, and another patient suffered pancreatic pseudocyst after the surgery, but no one died in hospital. Conclusion: Retroperitoneal laparoscopic debridement therapy is an additional choice for patients with infected severe acute pancreatitis, especially for those who had limited necrosis under retroperitoneal space. Furthermore, the therapy is in line with the concept of minimally invasive surgery and enhanced recovery after surgery.

[Retroperitoneal laparoscopic debridement therapy for infected severe acute pancreatitis]

Objective: To investigate the feasibility and availability of retroperitoneal laparoscopic debridement therapy for patients with infected severe acute pancreatitis. Methods: Clinical data of 6 patients with severe acute pancreatitis who underwent retroperitoneal laparoscopic necrotic tissue debridement therapy in the Severe Acute Pancreatitis Center of Sir Run Run Hospital between August 2014 and October 2015 was retrospectively analyzed. The laparoscopic instruments and sponge forceps were used to remove necrotic tissue under retroperitoneal space, and double-cavity drainage tube was left for continuous washing. The perioperative indicators were collected and analyzed. Results: Two of six patients underwent two surgeries, and the others underwent one surgery, with an average operation time of (220.0±58.3) minutes and a mean hospital stay time of 62.6 days (35-117 days). One patient underwent re-operation after 33 days because of intraperitoneal hemorrhage, and another patient suffered pancreatic pseudocyst after the surgery, but no one died in hospital. Conclusion: Retroperitoneal laparoscopic debridement therapy is an additional choice for patients with infected severe acute pancreatitis, especially for those who had limited necrosis under retroperitoneal space. Furthermore, the therapy is in line with the concept of minimally invasive surgery and enhanced recovery after surgery.

[Initial study of transthoracic echocardiography guided three-dimensional printing on the application of assessment of structural heart disease]

Objective: To investigate the feasibility and diagnostic value of preoperative transthoracic echocardiography guided three dimensional printing model (TTE Guided 3DPM) on the assessment of structural heart disease (SHD). Methods: From February 2016 to October 2016, 44 patients underwent cardiac surgery in Tianjin Chest Hospital, forty-four patients were assessed preoperatively using TTE Guided 3DPM, including 25 males and 19 females, aged 3-75 years, with an average of (44±22) years. compared to conventional three dimensional transthoracic echocardiography (3D-TTE), and took direct intraoperative findings as "Golden Standard" simultaneously. There are twelve patients with SHD, including four cases with mitral prolapse, two cases with partial endocardial cushion defect, two cases with secondary atrial septal defect, two cases with rheumatic mitral stenosis, one case with tetralogy of Fallot, one case with ventricular septal defect (VSD), thirty-two patients without SHD were designed as negative control. Results: The sensitivity and specificity of TTE Guided 3DPM were greater than or equal to 3D-TTE, P value of McNemar test of 3D-TTE was greater than 0.05, the difference was not statistically significant, kappa=0.745, P<0.01, indicated that the results of 3DTTE and the gold standard were generally consistent.P value of McNemar test of TTE Guided 3DPM was greater than 0.05, the difference was not statistically significant, kappa=0.955, P<0.01, indicated that the results of TTE Guided 3DPM and gold standards were consistent. Compared with 3D-TTE and TTE Guided 3DPM, P value was greater than 0.05, the difference was not statistically significant, kappa=0.879, P<0.01, indicated that the results of 3D-TTE and TTE Guided 3DPM were consistent. TTE Guided 3DPM displayed the three-dimensional structure of SHD cardiac lesions clearly, which were consistent with intraoperative findings. Conclusion: TTE Guided 3DPM provides essential information for the preoperative evaluation and decision of SHD.

Assessing the oseltamivir-induced resistance risk and implications for influenza infection control strategies

Background

Oseltamivir-resistant mutants with higher drug resistance rates and low trans-mission fitness costs have not accounted for influenza (sub)type viruses. Predicting the impacts of neuraminidase inhibitor therapy on infection rates and transmission of drug-resistant viral strains requires further investigation.

Objectives

The purpose of this study was to assess the potential risk of oseltamivir-induced resistance for influenza A (H1N1) and A (H3N2) viruses.

Materials and methods

An immune-response-based virus dynamic model was used to best fit the oseltamivir-resistant A (H1N1) and A (H3N2) infection data. A probabilistic risk assessment model was developed by incorporating branching process-derived probability distribution of resistance to estimate oseltamivir-induced resistance risk.

Results

Mutation rate and sensitive strain number were key determinants in assessing resistance risk. By increasing immune response, antiviral efficacy, and fitness cost, the spread of resistant strains for A (H1N1) and A (H3N2) were greatly decreased. Probability of resistance depends most strongly on the sensitive strain number described by a Poisson model. Risk of oseltamivir-induced resistance increased with increasing the mutation rate for A (H1N1) only. The ≥50% of resistance risk induced by A (H1N1) and A (H3N2) sensitive infected cells were 0.4 (95% CI: 0.28–0.43) and 0.95 (95% CI 0.93–0.99) at a mutation rate of 10⁻⁶, respectively. Antiviral drugs must be administrated within 1–1.5 days for A (H1N1) and 2–2.5 days for A (H3N2) virus infections to limit viral production.

Conclusion

Probabilistic risk assessment of antiviral drug-induced resistance is crucial in the decision-making process for preventing influenza virus infections.

Mathematical modeling of postcoinfection with influenza A virus and Streptococcus pneumoniae, with implications for pneumonia and COPD-risk assessment

Background

The interaction between influenza and pneumococcus is important for understanding how coinfection may exacerbate pneumonia. Secondary pneumococcal pneumonia associated with influenza infection is more likely to increase respiratory morbidity and mortality. This study aimed to assess exacerbated inflammatory effects posed by secondary pneumococcal pneumonia, given prior influenza infection.

Materials and methods

A well-derived mathematical within-host dynamic model of coinfection with influenza A virus and Streptococcus pneumoniae (SP) integrated with dose–response relationships composed of previously published mouse experimental data and clinical studies was implemented to study potentially exacerbated inflammatory responses in pneumonia based on a probabilistic approach.

Results

We found that TNFα is likely to be the most sensitive biomarker reflecting inflammatory response during coinfection among three explored cytokines. We showed that the worst inflammatory effects would occur at day 7 SP coinfection, with risk probability of 50% (likely) to develop severe inflammatory responses. Our model also showed that the day of secondary SP infection had much more impact on the severity of inflammatory responses in pneumonia compared to the effects caused by initial virus titers and bacteria loads.

Conclusion

People and health care workers should be wary of secondary SP infection on day 7 post-influenza infection for prompt and proper control-measure implementation. Our quantitative risk-assessment framework can provide new insights into improvements in respiratory health especially, predominantly due to chronic obstructive pulmonary disease (COPD).

Toxicity-based toxicokinetic/toxicodynamic assessment of bioaccumulation and nanotoxicity of zerovalent iron nanoparticles in Caenorhabditis elegans

Elucidating the relationships between the toxicity-based-toxicokinetic (TBTK)/toxicodynamic (TD) properties of engineered nanomaterials and their nanotoxicity is crucial for human health-risk analysis. Zerovalent iron (Fe⁰) nanoparticles (NPs) are one of the most prominent NPs applied in remediating contaminated soils and groundwater. However, there are concerns that Fe⁰NP application contributes to long-term environmental and human health impacts. The nematode Caenorhabditis elegans is a surrogate in vivo model that has been successfully applied to assess the potential nanotoxicity of these nanomaterials. Here we present a TBTK/TD approach to appraise bioaccumulation and nanotoxicity of Fe⁰NPs in C. elegans. Built on a present C. elegans bioassay with estimated TBTK/TD parameters, we found that average bioconcentration factors in C. elegans exposed to waterborne and food-borne Fe⁰NPs were ~50 and ~5×10^-3, respectively, whereas 10% inhibition concentrations for fertility, locomotion, and development, were 1.26 (95% CI 0.19-5.2), 3.84 (0.38-42), and 6.78 (2.58-21) μg·g^-1, respectively, implicating that fertility is the most sensitive endpoint in C. elegans. Our results also showed that biomagnification effects were not observed in waterborne or food-borne Fe⁰NP-exposed worms. We suggest that the TBTK/TD assessment for predicting NP-induced toxicity at different concentrations and conditions in C. elegans could enable rapid selection of nanomaterials that are more likely to be nontoxic in larger animals. We conclude that the use of the TBTK/TD scheme manipulating C. elegans could be used for rapid evaluation of in vivo toxicity of NPs or for drug screening in the field of nanomedicine.

Mixture risk assessment due to ingestion of arsenic, copper, and zinc from milkfish farmed in contaminated coastal areas

Human health risks associated with the consumption of metal-contaminated fish over extended periods have become a concern particularly in Taiwan, where fish is consumed on a large scale. This study applied the interaction-based hazard index (HI) to assess the mixture health risks for fishers and non-fishers who consume the arsenic (As), copper (Cu), and zinc (Zn) contaminated milkfish from As-contaminated coastal areas in Taiwan, taking into account joint toxic actions and potential toxic interactions. We showed that the interactions of As-Zn and Cu-Zn were antagonistic, whereas As-Cu interaction was additive. We found that HI estimates without interactions considered were 1.3-1.6 times higher than interactive HIs. Probability distributions of HI estimates for non-fishers were less than 1, whereas all 97.5%-tile HI estimates for fishers were >1. Analytical results revealed that the level of inorganic As in milkfish was the main contributor to HIs, indicating a health risk posed to consumers of fish farmed in As-contaminated areas. However, we found that Zn supplementation could significantly decrease As-induced risk of hematological effect by activating a Zn-dependent enzyme. In order to improve the accuracy of health risk due to exposure to multiple metals, further toxicological data, regular environmental monitoring, dietary survey, and refinement approaches for interactive risk assessment are warranted.

Anemia risk in relation to lead exposure in lead-related manufacturing

Background

Lead-exposed workers may suffer adverse health effects under the currently regulated blood lead (BPb) levels. However, a probabilistic assessment about lead exposure-associated anemia risk is lacking. The goal of this study was to examine the association between lead exposure and anemia risk among factory workers in Taiwan.

Methods

We first collated BPb and indicators of hematopoietic function data via health examination records that included 533 male and 218 female lead-exposed workers between 2012 and 2014. We used benchmark dose (BMD) modeling to estimate the critical effect doses for detection of abnormal indicators. A risk-based probabilistic model was used to characterize the potential hazard of lead poisoning for job-specific workers by hazard index (HI). We applied Bayesian decision analysis to determine whether BMD could be implicated as a suitable BPb standard.

Results

Our results indicated that HI for total lead-exposed workers was 0.78 (95% confidence interval: 0.50–1.26) with risk occurrence probability of 11.1%. The abnormal risk of anemia indicators for male and female workers could be reduced, respectively, by 67–77% and 86–95% by adopting the suggested BPb standards of 25 and 15 μg/dL.

Conclusions

We conclude that cumulative exposure to lead in the workplace was significantly associated with anemia risk. This study suggests that current BPb standard needs to be better understood for the application of lead-exposed population protection in different scenarios to provide a novel standard for health management. Low-level lead exposure risk is an occupational and public health problem that should be paid more attention.

Electronic supplementary material

The online version of this article (doi:10.1186/s12889-017-4315-7) contains supplementary material, which is available to authorized users.

Pterostilbene as treatment for severe acute pancreatitis

Acute pancreatitis (AP) has a fast onset and progression, which lead to an unfavorable prognosis. Therefore, the development of novel drugs for its treatment is critical. As a homologous derivative of resveratrol, pterostilbene exerts a variety of effects including anti-inflammatory, antioxidant, and antitumor effects. This study investigated the potential of pterostilbene for treatment of severe AP (SAP) and related mechanisms. Effects of pterostilbene were evaluated in a Wistar rat model of AP. Serum levels of amylase (AMY), creatinine (Cr), and alanine aminotransferase (ALT) were quantified. Furthermore, serum levels of tumor necrosis factor (TNF)-a and interleukin (IL)-1b were quantified using enzyme-linked immunosorbent assay. Nuclear factor (NF)-kB expression in pancreatic tissues was quantified by real-time PCR and western blotting. The production of reactive oxygen species (ROS) was determined using a spectrometer, while superoxide dismutase (SOD) activity was assayed. In the AP rat model, the expression of inflammatory markers TNF-a and IL-1b, expression of NF-kB, and serum indices (AMY, Cr, and ALT) increased compared to the corresponding levels in the control group (P < 0.05). Pterostilbene reduced serum levels of TNF-a and IL-1b; decreased NF-kB gene expression, serum indices, and ROS generation; and increased SOD activity in a dose-dependent manner. In conclusion, pterostilbene can alleviate SAP-induced tissue damage by decreasing the inflammatory response and by promoting antioxidation leading to the protection of pancreatic tissues.

Assessing exposure risks for freshwater tilapia species posed by mercury and methylmercury

Waterborne and dietborne exposures of freshwater fish to mercury (Hg) in the forms of inorganic (Hg(II)) and organic (methylmercury or MeHg) affect their growth, development, and reproduction. However, an integrated mechanistic risk model framework to predict the impact of Hg(II)/MeHg on freshwater fish is lacking. Here, we integrated biokinetic, physiological and biogeographic data to calibrate and then establish key risk indices-hazardous quotient and exceedance risk-for freshwater tilapia species across geographic ranges of several major rivers in Taiwan. We found that Hg(II) burden was highest in kidney followed by gill, intestine, liver, blood, and muscle. Our results showed that Hg was less likely to pose mortality risk (mortality rate less than 5 %) for freshwater tilapia species. However, Hg is likely to pose the potential hazard to aquatic environments constrained by safety levels for aquatic organisms. Sensitivity analysis showed that amount of Hg accumulated in tilapia was most influenced by sediment uptake rate. Our approach opens up new possibilities for predicting future fish population health with the impacts of continued Hg exposure to provide information on which fish are deemed safe for human consumption.

Ceramics manufacturing contributes to ambient silica air pollution and burden of lung disease

Inhalation of silica (SiO2) in occupational exposures can cause pulmonary fibrosis (silicosis), lung function deficits, pulmonary inflammation, and lung cancer. Current risk assessment models, however, cannot fully explain the magnitude of silica-induced pulmonary disease risk. The purpose of this study was to assess human health risk exposed to airborne silica dust in Taiwan ceramics manufacturing. We conducted measurements to characterize workplace-specific airborne silica dust in tile and commodity ceramic factories and used physiologically based alveolar exposure model to estimate exposure dose. We constructed dose-response models for describing relationships between exposure dose and inflammatory responses, by which health risks among workers can be assessed. We found that silica contents were 0.22-33.04 % with mean concentration ranges of 0.11-5.48 and 0.46-1763.30 μg m(-3), respectively, in commodity and tile ceramic factories. We showed that granulation workers in tile ceramic factory had the highest total SiO2 lung burden (∼1000 mg) with cumulative SiO2 lung burden of ∼4 × 10(4) mg-year. The threshold estimates with an effect on human lung inflammation and fibrosis are 407.31 ± 277.10 (mean ± sd) and 505.91 ± 231.69 mg, respectively. For granulation workers, long-term exposure to airborne silica dust for 30-45 years was likely to pose severe adverse health risks of inflammation and fibrosis. We provide integrated assessment algorithms required to implement the analyses and maintain resulting concentration of silica dust at safety threshold level in the hope that they will stimulate further analyses and interpretation. We suggest that decision-makers take action to implement platforms for effective risk management to prevent the related long-term occupational disease in ceramics manufacturing.

Quantifying the impact of drug combination regimens on TB treatment efficacy and multidrug resistance probability

OBJECTIVES

TB patients' non-adherence to the multidrug treatment regimen is thought to be the main cause of the emergence of drug resistance. The purpose of this study was to quantify the impacts of two-drug combination regimens and non-adherence to these regimens on treatment efficacy and drug resistance probability.

METHODS

A drug treatment modelling strategy was developed by incorporating a pharmacokinetic/pharmacodynamic model into a bacterial population dynamic model to explore the dynamics of TB bacilli and evolution of resistance during multidrug combination therapy, with an emphasis on non-adherence. A Hill-equation-based pharmacodynamic model was used to assess the bactericidal efficacy of single drugs and to estimate drug interactions.

RESULTS

Non-adherence to the treatment regimen increased treatment duration by nearly 1.6- and 3.4-fold relative to compliance with treatment. Symptom-based intermittent treatment, a form of non-adherence, might lead to treatment failure and accelerated growth and evolution of resistant mutants, resulting in a dramatically higher probability of 4.17 × 10(-3) (95% CI 2.10 × 10(-4)-1.28 × 10(-2)) for the emergence of MDR TB. Overall, determination of the optimal treatment regimen depended on the different types of medication adherence.

CONCLUSIONS

Our model not only predicts evolutionary dynamics, but also quantifies treatment efficacy. More broadly, our model provides a quantitative framework for improving treatment protocols and establishing an emergence threshold of resistance that can be used to prevent drug resistance.

De novo assembly and characterization of the root transcriptome and development of simple sequence repeat markers in Paphiopedilum concolor

Paphiopedilum orchids (Orchidaceae) have attracted much attention from botanists and horticulturists because of their peculiar leaves and beautiful flowers. Furthermore, the dry roots of Paphiopedilum plants have well-known medicinal uses. However, it is unknown how sensitive and plastic the root genes are to environmental changes or how these environmental changes regulate the biosynthesis of active ingredients. In this study, we chose Paphiopedilum concolor for root sequencing, as it is widely used as a parent in breeding experiments. A total of 3.77 Gb of sequence data were generated by Illumina paired-end sequencing. De novo assemblies yielded 72,952 contigs, 67,434 scaffolds, 64,304 unigenes with average lengths of 937, 1022, and 1047 bp, respectively. Based on Basic Local Alignment Search Tool with known protein sequences, 40,815 (63.5%) unigenes were annotated with an E-value cutoff of 1.0E-5. Among the unigenes, 24,605 were classified in the Gene Ontology database, 17,361 were assigned to Cluster of Orthologous Groups, and 14,170 were annotated in Kyoto Encyclopedia of Genes and Genomes. Among these annotations, over 1195 unigenes related to secondary metabolic pathways, as well as 609 unigenes involved in plant hormone synthesis and signal transduction, were identified. In addition, 5322 potential simple sequence repeats (SSRs) were identified, and 4989 primer pairs for 3975 sequences containing SSRs were obtained. This study provides valuable insights into the mechanisms of genes that regulate root growth and development and provides a comprehensive resource for genes related to secondary metabolism in roots and for marker-assisted studies in Paphiopedilum.

Neuropsychological functions among adolescents with persistent, subsyndromal and remitted attention deficit hyperactivity disorder

BACKGROUND

Previous studies have reported mixed results on neuropsychological deficits in attention deficit hyperactivity disorder (ADHD) and only a few studies have focused on adolescents. There is also a debate about whether the executive function (EF) impairments in ADHD are primary deficits or have some contribution from the underlying non-EF processes. The aim of this study was to investigate the impairments in EF and neuropsychological function with relatively low executive demand (low-EF) in adolescents with childhood diagnosis of ADHD as a function of current ADHD status.

METHOD

Psychiatric diagnostic interviews and computerized neuropsychological tests classified into EF and low-EF tasks were completed by 435 adolescents with a childhood diagnosis of ADHD (300 adolescents classified as persistent ADHD, 109 as subsyndromal ADHD and 26 as remitted ADHD based on the current diagnosis) and 263 typically developing (TD) adolescents.

RESULTS

There were significant EF (spatial working memory, spatial planning and verbal working memory) and low-EF (signal detectability, spatial span and visual recognition memory) impairments in persistent and subsyndromal ADHD. The impairments in EF were independent of low-EF despite significant moderate correlations between any two of these tasks. Adolescents with remitted ADHD showed no deficit in either EF or low-EF.

CONCLUSIONS

This study suggests that adolescents with persistent and subsyndromal ADHD have EF and low-EF impairments that might contribute to ADHD independently.

[Investigation of spectroscopy of ZnCuInS/ZnSe/ZnS quantum dots]

ZnCuInS/ZnSe/ZnS quantum dots were non-toxic and heavy-metal free semiconductor nanocrystals. In the present paper, ZnCuInS/ZnSe/ZnS core/shell/shell quantum dots were prepared with the particle size of 3.3, 2.7 and 2.3 nm. The photoluminescence of ZnCuInS/ZnSe/ZnS quantum dots with different size were measured, and the wavelength of peak was blue-shifted with decreasing the diameter. The wavelength of absorption peaks and photoluminescence peaks were 510 nm, 611 nm (3.3 nm), 483 nm, 583 nm (2.7 nm) and 447 nm and 545 nm(2.3 nm). The obvious size-dependence of ZnCuInS/ZnSe/ZnS quantum dots was shown. The Stokes shifts of ZnCuInS/ZnSe/ZnS quantum dots were 398 meV (3.3 nm), 436 meV (2.7 nm) and 498 meV (2.3 nm). Such large Stokes shifts indicate that the emission should be ascribed to the defect-related recombination. The temperature-dependent photoluminescence of ZnCuInS/ZnSe/ZnS quantum dots with the particle size of 3.3 nm were measured. The wavelength of peaks was red-shifted with increasing temperature and the intensity of photoluminescence spectra was decreased with increasing temperature. Therefore, the emission was concluded to be the transition from the conduction band to defect state.

A probabilistic transmission and population dynamic model to assess tuberculosis infection risk

The purpose of this study was to examine tuberculosis (TB) population dynamics and to assess potential infection risk in Taiwan. A well-established mathematical model of TB transmission built on previous models was adopted to study the potential impact of TB transmission. A probabilistic risk model was also developed to estimate site-specific risks of developing disease soon after recent primary infection, exogenous reinfection, or through endogenous reactivation (latently infected TB) among Taiwan regions. Here, we showed that the proportion of endogenous reactivation (53-67%) was larger than that of exogenous reinfection (32-47%). Our simulations showed that as epidemic reaches a steady state, age distribution of cases would finally shift toward older age groups dominated by latently infected TB cases as a result of endogenous reactivation. A comparison of age-weighted TB incidence data with our model simulation output with 95% credible intervals revealed that the predictions were in an apparent agreement with observed data. The median value of overall basic reproduction number (R₀) in eastern Taiwan ranged from 1.65 to 1.72, whereas northern Taiwan had the lowest R₀ estimate of 1.50. We found that total TB incidences in eastern Taiwan had 25-27% probabilities of total proportion of infected population exceeding 90%, whereas there were 36-66% probabilities having exceeded 20% of total proportion of infected population attributed to latently infected TB. We suggested that our Taiwan-based analysis can be extended to the context of developing countries, where TB remains a substantial cause of elderly morbidity and mortality.

Assessing the transmission risk of multidrug-resistant Mycobacterium tuberculosis epidemics in regions of Taiwan

OBJECTIVE

The objective of this study was to link transmission dynamics with a probabilistic risk model to provide a mechanistically explicit assessment for estimating the multidrug-resistant tuberculosis (MDR TB) infection risk in regions of Taiwan.

METHODS

A relative fitness (RF)-based MDR TB model was used to describe transmission, validated with disease data for the period 2006-2010. A dose-response model quantifying by basic reproduction number (R(0)) and total proportion of infected population was constructed to estimate the site-specific MDR TB infection risk.

RESULTS

We found that the incidence rate of MDR TB was highest in Hwalien County (4.91 per 100,000 population) in eastern Taiwan, with drug-sensitive and multidrug-resistant R(0) estimates of 0.89 (95% CI 0.23-2.17) and 0.38 (95% CI 0.05-1.30), respectively. The predictions were in apparent agreement with observed data in the 95% credible intervals. Our simulation showed that the incidence of MDR TB will be falling by 2013-2016. Our results indicated that the selected regions of Taiwan had only ∼1% probability of exceeding 50% of the population with infection attributed to MDR TB.

CONCLUSIONS

Our study found that the ongoing control programs implemented in Taiwan may succeed in curing most patients with MDR TB and will reduce the TB incidence countrywide.

Assessing trends and predictors of tuberculosis in Taiwan

BACKGROUND

Variety of environmental and individual factors can cause tuberculosis (TB) incidence change. The purpose of this study was to assess the characteristics of TB trends in the period 2004 - 2008 in Taiwan by month, year, gender, age, temperature, seasonality, and aborigines.

METHODS

The generalized regression models were used to examine the potential predictors for the monthly TB incidence in regional and national scales.

RESULTS

We found that (i) in Taiwan the average TB incidence was 68 per 100,000 population with mortality rate of 0.036 person-1 yr-1, (ii) the highest TB incidence rate was found in eastern Taiwan (116 per 100,000 population) with the largest proportion of TB relapse cases (8.17%), (iii) seasonality, aborigines, gender, and age had a consistent and dominant role in constructing TB incidence patterns in Taiwan, and (iv) gender, time trend, and 2-month lag maximum temperature showed strong association with TB trends in aboriginal subpopulations.

CONCLUSIONS

The proposed Poisson regression model is capable of forecasting patterns of TB incidence at regional and national scales. This study suggested that assessment of TB trends in eastern Taiwan presents an important opportunity for understanding the time-series dynamics and control of TB infections, given that this is the typical host demography in regions where these infections remain major public health problems.

Assessing the potential exposure risk and control for airborne titanium dioxide and carbon black nanoparticles in the workplace

PURPOSE

This study assessed the potential exposure risks for workers in the workplace exposed to airborne titanium dioxide nanoparticles (TiO(2)-NPs) and carbon black nanoparticles (CB-NPs). The risk management control strategies were also developed for the NP engineering workplace.

METHODS

The method used in this study was based on the integrated multiple-path particle dosimetry model to estimate the cumulative dose of nanoparticles (NPs) in the human lung. The study then analyzed toxicological effects such as pulmonary cytotoxicity and inflammation and evaluated the health risk associated with exposure to NPs in the workplace. Risk control measures such as the use of ventilating systems and N95 respirator protection are also discussed.

RESULTS AND DISCUSSION

This study found that: (1) the cumulative dose of CB-NPs was greater than that of TiO(2)-NPs in human lungs; (2) there is a potential health risk to workers exposed to TiO(2)-NPs and CB-NPs in the absence of control measures in the workplace, with higher health risks associated with CB-NPs than TiO(2)-NPs; and (3) the use of a ventilating system and an N95 respirator offers greater protection in the workplace and significantly reduces the health risks associated with NP exposure.

CONCLUSION

The present risk management control strategy suggests that the most effective way to reduce airborne NPs is to incorporate the use of a ventilating system combined with N95 respirator protection. This will enable the concentrations of TiO(2)-NPs and CB-NPs to be reduced to acceptable exposure levels.

Dysregulated brain creatine kinase is associated with hearing impairment in mouse models of Huntington disease

Huntington disease (HD) is a degenerative disorder caused by expanded CAG repeats in exon 1 of the huntingtin gene (HTT). Patients with late-stage HD are known to have abnormal auditory processing, but the peripheral auditory functions of HD patients have yet to be thoroughly assessed. In this study, 19 HD patients (aged 40-59 years) were assessed for hearing impairment using pure-tone audiometry and assessment of auditory brainstem responses (ABRs). PTA thresholds were markedly elevated in HD patients. Consistent with this, elevated ABR thresholds were also detected in two mouse models of HD. Hearing loss thus appears to be an authentic symptom of HD. Immunohistochemical analyses demonstrated the presence of mutant huntingtin that formed intranuclear inclusions in the organ of Corti of HD mice, which might interfere with normal auditory function. Quantitative RT-PCR and Western blot analyses further revealed reduced expression of brain creatine kinase (CKB), a major enzyme responsible for ATP regeneration via the phosphocreatine-creatine kinase (PCr-CK) system, in the cochlea of HD mice. Treatment with creatine supplements ameliorated the hearing impairment of HD mice, suggesting that the impaired PCr-CK system in the cochlea of HD mice may contribute to their hearing impairment. These data also suggest that creatine may be useful for treating the hearing abnormalities of patients with HD.

Genetic polymorphisms of the DNA repair gene MPG may be associated with susceptibility to rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic autoimmune disease and can lead to deformities and severe disabilities, due to irreversible damage of tendons, joints, and bones. A previous study indicated that a DNA repair system was involved in the development of RA. In this study, we investigated the association of four N-methylpurine-DNA glycosylase (MPG) gene polymorphisms (rs3176364, rs710079, rs2858056, and rs2541632) with susceptibility to RA in 384 Taiwanese individuals (192 RA patients and 192 control subjects). Our data show a statistically significant difference in genotype frequency distributions at rs710079 and rs2858056 SNPs between RA patients and control groups (P = 0.040 and 0.029, respectively). Our data also indicated that individuals with the GG genotype at rs2858056 SNP may have a higher risk of developing RA. In addition, compared with the haplotype frequencies between case and control groups, individuals with the GCGC haplotype appeared to be at a greater risk of RA progression (P = 0.003, OR = 1.75; 95&percnt; CI = 1.20-1.55). Our results suggest that rs710079 and rs2858056 polymorphisms and the GCGC haplotype in the MPG gene are associated with the risk of RA progression, and thus may be used as molecular markers of RA if they are confirmed by further research.

Pharmacokinetics of ketamine in plasma and milk of mature Holstein cows

The purpose of this study was to evaluate the pharmacokinetics of ketamine in mature Holstein cows following administration of a single intravenous (i.v.) dose. Plasma and milk concentrations were determined using a high-performance liquid chromatography assay. Pharmacokinetic parameters were estimated using a noncompartmental method. Following i.v. administration, plasma T(max) was 0.083 h and plasma C(max) was 18,135 ± 22,720 ng/mL. Plasma AUC was 4484 ± 1,398 ng·h/mL. Plasma t(½β) was 1.80 ± 0.50 h and mean residence time was 0.794 ± 0.318 h with total body clearance of 1.29 ± 0.70 L/h/kg. The mean plasma steady-state volume of distribution was calculated as 0.990 ± 0.530 L/kg and volume of distribution based on area was calculated as 3.23 ± 1.51 L/kg. The last measurable time for ketamine detection in plasma was 8.0 h with a mean concentration of 24.9 ± 11.8 ng/mL. Milk T(max) was detected at 0.67 ± 0.26 h with C(max) of 2495 ± 904 ng/mL. Milk AUC till the last time was 6593 ± 2617 ng·h/mL with mean AUC milk to AUC plasma ratio of 1.99 ± 2.15. The last measurable time that ketamine was detected in milk was 44 ± 10.0 h with a mean concentration of 16.0 ± 9.0 ng/mL.

Stress-induced phosphoprotein 1 as a secreted biomarker for human ovarian cancer promotes cancer cell proliferation

Ovarian cancers are frequently not diagnosed until advanced stages, resulting in a high case fatality rate. Because of this, more tumor markers, in addition to CA125, for detecting and monitoring ovarian cancer are needed. During a systematic search for potential biomarkers of ovarian cancer, we compared the protein profiles between tumor interstitial fluid and normal interstitial fluid of ovaries, rationalizing that abnormal levels of proteins in tumor interstitial fluid may be detected in peripheral blood and thus serve as easily accessible tumor markers. Here, we show that stress-induced phosphoprotein 1 (STIP1) was secreted by ovarian cancer tissues into the peripheral blood of patients, resulting in a significant increase of serum levels of STIP1 in cancer patients compared with those in age-matched normal controls. Our results further indicated that combined use of CA125 and STIP1 may increase early detection of ovarian cancer. Functionally, recombinant STIP1 significantly induced ERK phosphorylation, promoted DNA synthesis, and increased Ki-67 immunoreactivity in ovarian cancer cells, suggesting that STIP1 in vitro promotes cell proliferation. Colocalization of STIP1 and phospho-ERK in human ovarian cancer tissues also supports an in vivo activation of ERK by STIP1. Further understanding of molecular roles of STIP1 in human ovarian cancer may shed light on its pathophysiology and development of novel therapeutic strategies.