Light in the Larynx: a Miniaturized Robotic Optical Fiber for In-office Laser Surgery of the Vocal Folds.

This paper reports the design, construction, and experimental validation of a novel hand-held robot for in-office laser surgery of the vocal folds. In-office endoscopic laser surgery is an emerging trend in Laryngology: It promises to deliver the same patient outcomes of traditional surgical treatment (i.e., in the operating room), at a fraction of the cost. Unfortunately, office procedures can be challenging to perform; the optical fibers used for laser delivery can only emit light forward in a line-of-sight fashion, which severely limits anatomical access. The robot we present in this paper aims to overcome these challenges. The end effector of the robot is a steerable laser fiber, created through the combination of a thin optical fiber (ϕ 0.225 mm) with a tendon-actuated Nickel-Titanium notched sheath that provides bending. This device can be seamlessly used with most commercially available endoscopes, as it is sufficiently small (ϕ 1.1 mm) to pass through a working channel. To control the fiber, we propose a compact actuation unit that can be mounted on top of the endoscope handle, so that, during a procedure, the operating physician can operate both the endoscope and the steerable fiber with a single hand. We report simulation and phantom experiments demonstrating that the proposed device substantially enhances surgical access compared to current clinical fibers.

Minors are the most affected by Chlamydia trachomatis in Reunion Island: A cross-sectional study, 2017-2018.

OBJECTIVES: To determine the prevalence of Chlamydia trachomatis (CT) in the population screened at sexually transmitted infection (STI) clinics on Reunion Island and to identify risk factors for CT infection. PATIENTS AND METHODS: This cross-sectional multicenter study was conducted in 2017-2018. Data were obtained from self-administered questionnaires and multiplex PCR tests. RESULTS: The overall prevalence of CT in the screened population was 8.6% (95% CI 7.7-9.5%). The prevalence of urogenital CT was highest in women under 18 (13.2%, 95% CI 9.3-18.1%) and in men who have sex with men under 18 (13.3%, 95% CI 1.6-48.2%). Risk factors associated with CT infection in multivariate analysis were: female gender, being born in Reunion Island, having had a large number of sexual partners in the past year, and being co-infected with another STI. CONCLUSIONS: The prevalence of CT in the screened population is higher in Reunion Island than in mainland France, especially in minors. Prevention campaigns targeting minors should be strengthened.

A novel circular ssDNA virus of the phylum Cressdnaviricota discovered in metagenomic data from otter clams (Lutraria rhynchaena).

In this study, we present an analysis of metagenome sequences obtained from a filtrate of a siphon tissue homogenate of otter clams (Lutraria rhynchaena) with swollen-siphon disease. The viral signal was mined from the metagenomic data, and a novel circular ssDNA virus was identified. Genomic features and phylogenetic analysis showed that the virus belongs to the phylum Cressdnaviricota, which consists of viruses with circular, single-stranded DNA (ssDNA) genomes. Members of this phylum have been identified in various species and in environmental samples. The newly found virus is distantly related to the currently known members of the phylum Cressdnaviricota.

Caspase Activation and Caspase-Mediated Cleavage of APP Is Associated with Amyloid ß-Protein-Induced Synapse Loss in Alzheimer's Disease.

Amyloid ß-protein (Aß) toxicity is hypothesized to play a seminal role in Alzheimer's disease (AD) pathogenesis. However, it remains unclear how Aß causes synaptic dysfunction and synapse loss. We hypothesize that one mechanism of Aß-induced synaptic injury is related to the cleavage of amyloid ß precursor protein (APP) at position D664 by caspases that release the putatively cytotoxic C31 peptide. In organotypic slice cultures derived from mice with a knock-in mutation in the APP gene (APP D664A) to inhibit caspase cleavage, Aß-induced synaptic injury is markedly reduced in two models of Aß toxicity. Loss of dendritic spines is also attenuated in mice treated with caspase inhibitors. Importantly, the time-dependent dendritic spine loss is correlated with localized activation of caspase-3 but is absent in APP D664A cultures. We propose that the APP cytosolic domain plays an essential role in Aß-induced synaptic damage in the injury pathway mediated by localized caspase activation.

Risk factors for colonization and infection by Pseudomonas aeruginosa in patients hospitalized in intensive care units in France.

OBJECTIVE: To assess the role of environment, medical care and individual risks factors for P. aeruginosa colonization and infection. STUDY DESIGN AND SETTING: A French multicentric prospective study involved ten ICUs for a five months period. Every adult patient newly hospitalized in ICUs with no P. aeruginosa carriage up to 48 hours after admission was included and weekly screened before discharge or death. Screening swabs were either rectal, sputum or oropharyngeal samples. Hydric environment was also sampled each week. Data on patient clinical features, environmental and device exposures, and antibiotics supports were regularly collected. Multivariate analysis was performed with a multistate model. RESULTS: The overall prevalence of P. aeruginosa carriage was 15.3% (201/1314). Risk factors associated with patient colonization were: use of inactive antibiotics against P. aeruginosa (HR = 1.60 [1.15-2.21] p<0.01), tap water contamination at the entry in the room (HR = 1.66 [1.01-2.27] p<0.05) and mechanical invasive ventilation (HR = 4.70 [2.66-8.31] p<0.0001). Active antibiotics prevented from colonization (HR = 0.67 [0.48-0.93] p = 0.02) and from infection (HR = 0.64 [0.41-1.01] p = 0.05). Interaction between hydric environment antibiotics support was not statistically associated with patient colonization. CONCLUSION: Hydric contamination and antibiotics pressure seem to remain key independent risk factors in P. aeruginosa colonization. These results advocate the need to carry on preventive and targeted interventions toward healthcare associated infections.

A simple laboratory algorithm for diagnosis of melioidosis in resource-constrained areas: a study from north-central Vietnam.

OBJECTIVES: Melioidosis may be endemic in many tropical developing countries, but diagnosis of the disease is currently unreliable in resource-limited areas. We aimed to validate a simple and cheap laboratory algorithm for the identification of Burkholderia pseudomallei from clinical specimens in parts of Vietnam where the disease has not previously been reported. METHODS: In June 2015, we conducted training courses at five general hospitals in north-central provinces in order to raise awareness of the disease and to introduce a simple and cheap laboratory identification algorithm for B. pseudomallei including the three-antibiotic disc test. RESULTS: Until the end of the year (7 months later), 94 suspected B. pseudomallei strains resistant to gentamicin and colistin but sensitive to amoxicillin/clavulanic acid were detected in clinical specimens from 70 patients. All strains were further confirmed as B. pseudomallei by using a specific TTSS1 real-time PCR assay and recA sequencing analysis. Among positive blood cultures, positive rates with B. pseudomallei ranged from 3.4% (5/147) to 10.2% (32/312) in the various clinics. A total of 82.8% (58/70) patients were bacteraemic, with a mortality of 50% (18/36) among patients with known outcome. No death occurred in nonbacteraemic patients. CONCLUSIONS: Our results demonstrate that the introduction of a simple and easy-to-perform laboratory algorithm for the identification of B. pseudomallei from clinical samples, together with clinical awareness raising, can lead to the diagnosis of a significant number of melioidosis cases in resource-limited clinical laboratories which previously did not identify the pathogen.

Pharmacotoxicology of clinically-relevant concentrations of obeticholic acid in an organotypic human hepatocyte system.

Nonalcoholic steatohepatitis (NASH) is an emerging health crisis with no approved therapies. Obeticholic acid (OCA), a farnesoid X receptor (FXR) agonist, shows promise in NASH trials. However, the precise mechanisms mediating OCA effects and impact on cholesterol metabolism are not fully understood. We explored the pharmaco-toxicological effects of OCA on patho-physiological pathways in hepatocytes using a previously described perfused organotypic liver system that allows culture in near-physiological insulin/glucose milieus, and exhibits drug responses at clinically-relevant concentrations. Primary hepatocytes experienced 48-hour exposure to OCA at concentrations approximating therapeutic (0.5µM) and supratherapeutic (10µM) levels. Global transcriptomics by RNAseq was complimented by cellular viability (MTT), CYP activity assays, and secreted FGF19 levels in the media. Dose-dependent, transcriptional effects suggested suppression of bile acid synthesis (↓CYP7A1, ↓CYP27A1) and increased bile efflux (↑ABCB4, ↑ABCB11, ↑OSTA, ↑OSTB). Pleiotropic effects included suppression of TGFß and IL-6 signaling pathways, and signatures suggestive of HDL suppression (↑SCARB1, ↓ApoAI, ↓LCAT) and LDL elevation (↑ApoB, ↓CYP7A1). OCA exhibited direct FXR-mediated effects with increased FGF19 secretion. Transcriptomics revealed regulation of metabolic, anti-inflammatory, and anti-fibrotic pathways beneficial in NASH, and predicted cholesterol profiles consistent with clinical findings. Follow-up studies under lipotoxic/inflammatory conditions would corroborate these effects in a disease-relevant environment.

The multifaceted nature of amyloid precursor protein and its proteolytic fragments: friends and foes.

The amyloid precursor protein (APP) has occupied a central position in Alzheimer's disease (AD) pathophysiology, in large part due to the seminal role of amyloid-ß peptide (Aß), a proteolytic fragment derived from APP. Although the contribution of Aß to AD pathogenesis is accepted by many in the research community, recent studies have unveiled a more complicated picture of APP's involvement in neurodegeneration in that other APP-derived fragments have been shown to exert pathological influences on neuronal function. However, not all APP-derived peptides are neurotoxic, and some even harbor neuroprotective effects. In this review, we will explore this complex picture by first discussing the pleiotropic effects of the major APP-derived peptides cleaved by multiple proteases, including soluble APP peptides (sAPPα, sAPPß), various C- and N-terminal fragments, p3, and APP intracellular domain fragments. In addition, we will highlight two interesting sequences within APP that likely contribute to this duality in APP function. First, it has been found that caspase-mediated cleavage of APP in the cytosolic region may release a cytotoxic peptide, C31, which plays a role in synapse loss and neuronal death. Second, recent studies have implicated the -YENPTY- motif in the cytoplasmic region as a domain that modulates several APP activities through phosphorylation and dephosphorylation of the first tyrosine residue. Thus, this review summarizes the current understanding of various APP proteolytic products and the interplay among them to gain deeper insights into the possible mechanisms underlying neurodegeneration and AD pathophysiology.

Long-term persistence and switching patterns among women using osteoporosis therapies: 24- and 36-month results from POSSIBLE US™.

UNLABELLED: Persistence with postmenopausal osteoporosis (PMO) medications is not well characterized beyond 12 months. Of 3,011 postmenopausal women treated in primary care, 36.8 % continued baseline PMO medication during 36 months of follow-up. Many factors were associated with nonpersistence, including newly initiating or switching therapy, and reporting moderate to severe side effects. INTRODUCTION: Persistence with postmenopausal osteoporosis (PMO) medications is not well characterized beyond 12 months. We describe 24- and 36-month persistence using patient-reported data from women with different PMO treatment histories in the US primary care setting. METHODS: Data from 3,011 participants of the Prospective Observational Scientific Study Investigating Bone Loss Experience (POSSIBLE US™, 10/2005-12/2008) and Kaplan-Meier methods were used to estimate the probability of persisting (i.e., not discontinuing or switching PMO agents) with baseline PMO medication and hazard ratios for predictors of nonpersistence 24 and 36 months after study entry. RESULTS: The probability of persisting with the baseline medication was 46.2 % (95 % confidence interval [CI] 44.2-48.1 %) during 24 months of follow-up and 36.8 % (95 % CI 34.7-38.9 %) during 36 months of follow-up. In adjusted analyses, newly initiating therapy or switching to a new agent, reporting moderate to severe side effects, having lower disease-specific quality of life scores, smoking, and residing in the South or West USA (all measured at study entry) were independent predictors of nonpersistence in both time periods. The majority of participants who discontinued therapy and had the opportunity to reinitiate (i.e., discontinued ≥4 months before the end of follow-up) restarted therapy (24 months 69 %; 36 months 75 %). CONCLUSIONS: In this primary care cohort, a minority of women continued their baseline PMO therapy during a 24- to 36-month follow-up. Supporting patients during the initiation of a new therapy or if side effects occur may improve persistence and increase the therapeutic benefit of PMO medications.

Treatment satisfaction and persistence among postmenopausal women on osteoporosis medications: 12-month results from POSSIBLE US™.

SUMMARY: Women in POSSIBLE US™ who expressed greater treatment satisfaction at study entry were more likely to persist with osteoporosis therapy over a 1-year period. Lower satisfaction among women with moderate/severe side effects increased the risk of discontinuation/switching by 67%. Treatment satisfaction and side effect experience influence osteoporosis medication adherence. INTRODUCTION: Non-adherence is common among women using postmenopausal osteoporosis (PMO) medications. We describe the association between treatment satisfaction, measured with the Treatment Satisfaction Questionnaire for Medication (TSQM), and the risk of discontinuation/switching PMO medications using patient-reported data from a large, longitudinal cohort study. METHODS: Data from 2,405 participants in the Prospective Observational Scientific Study Investigating Bone Loss Experience (POSSIBLE US™) Study were evaluated. Cox proportional hazards regression was used to estimate hazard ratios (HR) for the association between treatment satisfaction at study entry and self-reported discontinuation/switching of pharmacologic PMO medications over a 1-year follow-up period. Logistic regression was used to evaluate relationships between treatment satisfaction, lifestyle behaviors, and compliance with bisphosphonate dosing instructions. RESULTS: Median TSQM scores were highest (indicating greatest satisfaction) for the side effects domain [n = 1,182; median = 87.5 (Q1 = 75.0, Q3 = 100.0)] and lowest for global satisfaction [n = 2,340; median = 64.0 (Q1 = 55.7, Q3 = 77.7)]. Median scores decreased for the side effects and global satisfaction domains as patient-reported side effect severity increased. Women with higher satisfaction were less likely to discontinue/switch medications than women with lower scores (adjusted HRs for convenience 0.73, 95% CI = 0.63-0.85; effectiveness 0.82, 95% CI = 0.70-0.97; and global satisfaction 0.73, 95% CI = 0.63-0.85). Lower treatment satisfaction was particularly influential among women who reported moderate/severe side effects (HR = 0.60, 95% CI = 0.37-0.97). CONCLUSIONS: Lower treatment satisfaction was associated with a 22% (1/0.82) to 67% (1/0.60) increased risk of discontinuation/switching osteoporosis medication during 1 year of follow-up.

Final results of the DAPS (Denosumab Adherence Preference Satisfaction) study: a 24-month, randomized, crossover comparison with alendronate in postmenopausal women.

UNLABELLED: The final analysis of this 2-year, randomized, crossover study showed that postmenopausal women with osteoporosis were more adherent, compliant, and persistent with subcutaneous denosumab injections every 6 months than with once-weekly alendronate tablets. After receiving both treatments, women reported greater satisfaction with injectable denosumab and preferred it over oral alendronate. INTRODUCTION: Osteoporosis patients who are non-compliant or non-persistent with therapy may have suboptimal clinical outcomes. This 2-year, randomized, open-label, crossover study compared treatment adherence between subcutaneous denosumab, 60 mg every 6 months, and oral alendronate, 70 mg once weekly. METHODS: Postmenopausal women at 25 centers in the USA and Canada with bone mineral density T-scores -4.0 to -2.0 and no prior bisphosphonate use received alendronate then denosumab, or denosumab then alendronate, over successive 12-month periods. Adherence required both compliance (denosumab injections 6 months apart or ≥ 80% of alendronate tablets) and persistence (both denosumab injections or ≥ 2 alendronate doses in the last month and completion of the treatment period). RESULTS: Of the 250 women enrolled (124 alendronate, 126 denosumab), 221 entered the second year (106 denosumab, 115 alendronate). Denosumab was associated with less non-adherence than alendronate (first year, 11.9% vs 23.4%; second year, 7.5% vs 36.5%). Risk ratios for non-adherence, non-compliance, and non-persistence favored denosumab in both years (p < 0.05). Of 198 subjects expressing treatment preference, 183 (92.4%) preferred the injections over the oral therapy. BMD improved further when subjects received denosumab after alendronate and remained stable when they received alendronate after denosumab. CONCLUSION: Based on the final results of this crossover study after women had received each treatment for up to 1 year, postmenopausal women with osteoporosis were more adherent, compliant, and persistent with subcutaneous denosumab injections every 6 months than with once-weekly alendronate tablets and reported increased treatment preference and satisfaction with injectable denosumab over oral alendronate.

Adherence, preference, and satisfaction of postmenopausal women taking denosumab or alendronate.

UNLABELLED: In this study, 250 women with osteoporosis were randomized to 12 months with subcutaneous denosumab 60 mg every 6 months or oral alendronate 70 mg once weekly, then crossed over to the other treatment. The primary endpoint, treatment adherence at 12 months, was 76.6% for alendronate and 87.3% for denosumab. INTRODUCTION: The purpose of this study is to evaluate treatment adherence with subcutaneous denosumab 60 mg every 6 months or oral alendronate 70 mg once weekly. METHODS: In this multicenter, randomized, open-label, 2-year, crossover study, 250 postmenopausal women with low bone mineral density received denosumab or alendronate for 12 months, then the other treatment for 12 months. The alendronate bottle had a medication event monitoring system cap to monitor administration dates. Definitions were as follows: compliance, receiving both denosumab doses 6 (± 1) months apart or 80-100% of alendronate doses; persistence, receiving both denosumab doses and completing the month 12 visit within the visit window or ≥ 2 alendronate doses in the final month; adherence, achieving both compliance and persistence. This report includes data from the first 12 months. RESULTS: The primary study endpoint, adherence in the first 12 months, was 76.6% (95/124) for alendronate and 87.3% (110/126) for denosumab. Risk ratios for denosumab compared with alendronate at 12 months were 0.58 (p = 0.043) for non-adherence, 0.48 (p = 0.014) for non-compliance, and 0.54 (p = 0.049) for non-persistence. Subject ratings for treatment necessity, preference, and satisfaction were significantly greater for denosumab and ratings for treatment bother were significantly greater for alendronate. Adverse events were reported by 64.1% of alendronate-treated subjects and 72.0% of denosumab-treated subjects (p = 0.403). The most common adverse events were arthralgia, back pain, pain in extremity, cough, and headache (each in <10% of subjects in each group). CONCLUSIONS: Significantly greater treatment adherence was observed for subcutaneous administration of denosumab every 6 months than for oral alendronate once weekly.

Bronchoalveolar neutrophils, interferon gamma-inducible protein 10 and interleukin-7 in AIDS-associated tuberculosis.

During advanced AIDS tuberculosis (TB) often presents atypically with smear-negative and non-cavitary disease, yet immune features associated with this change are poorly characterized. We examined the local immune response in a cohort of Tanzanian AIDS-associated TB patients who underwent bronchoalveolar lavage. TB infection was confirmed in bronchoalveolar lavage (BAL) fluid by culture, probe and polymerase chain reaction (PCR). Among TB patients CD4 count correlated positively with the extent of cavitary disease as well as BAL TB load (qPCR C(T)). TB patients had significantly higher granulocyte-macrophage colony-stimulating factor (GM-CSF) than non-TB patients, and those with non-cavitary TB had significantly higher BAL interferon gamma-inducible protein (IP-10) and interleukin (IL)-7 than those with cavities. BAL neutrophils were as prevalent as monocytes/macrophages or epithelial cells, and immunohistochemistry revealed that neutrophils, monocytes/macrophages, and epithelial cells were major sources of the IP-10 and IL-7. These data suggest a dysregulated cytokine profile may contribute to the TB of advanced AIDS.

Brachial arteriovenous fistula as a complication of placement of a peripherally inserted central venous catheter: a case report and review of the literature.

Peripherally inserted central venous catheter (PICC) lines have become a frequently used method of intravenous access for long-term administration of antibiotics, chemotherapy, and parenteral nutrition. Catheter-related complications involving the arterial tree are rare. We report a case of a 25-year-old woman with a history of difficult PICC line placement that presented with an arteriovenous fistula in the left arm. Duplex ultrasound confirmed the diagnosis of a brachial artery-to-brachial vein arteriovenous fistula (AVF), and the patient underwent surgical repair. To our knowledge, this is the first reported case of an AVF resulting from PICC line placement. Correction of AVF is indicated to alleviate symptoms as well as to prevent future complications.

Ultrasound is not a useful screening tool for acute acalculous cholecystitis in critically ill trauma patients.

Acute acalculous cholecystitis remains a diagnostic challenge in critically ill trauma patients. Laboratory studies are nonspecific and associated injuries or mental status changes may mask clinical signs and symptoms. We conducted a retrospective study to assess the utility of ultrasound in the diagnosis of acute acalculous cholecystitis. We hypothesized that ultrasound is inadequate as a screening tool for acute acalculous cholecystitis. The abdominal ultrasounds of all patients undergoing evaluation for acute acalculous cholecystitis in a 40-month period at our Level I trauma center were reviewed. Thickened gallbladder wall, pericholecystic fluid and emphysematous gallbladder were considered positive sonographic criteria. Sludge, cholelithiasis, and hydrops were considered suggestive. Patients who did not undergo cholecystectomy had their gallbladders evaluated either during subsequent laparotomy or at autopsy or they were discharged from the hospital without need for intervention. Sixty-two patients were included. Twenty-one patients underwent cholecystectomy for presumed acute acalculous cholecystitis. The data revealed a sensitivity of 30 per cent (6/20) and a specificity of 93 per cent (39/42) for ultrasound evaluation. Twenty patients had subsequent hepatobiliary scans [hepato-iminodiacetic acid (HIDA)] with a sensitivity of 100 per cent (12/12) and specificity of 88 per cent (7/8). Our data do not support ultrasound as a reliable routine screening tool for acute acalculous cholecystitis. Despite its convenience as a bedside procedure ultrasound has insufficient sensitivity to justify its use and a more sensitive diagnostic tool should be used.

Ability of the American College of Rheumatology 1987 criteria to predict rheumatoid arthritis in patients with early arthritis and classification of these patients two years later.

OBJECTIVE: To determine how well the American College of Rheumatology (ACR; formerly, the American Rheumatism Association) 1987 classification criteria for rheumatoid arthritis (RA), when used at study inclusion in a cohort of 270 patients with early (<1 year) arthritis, predicted a diagnosis of RA 2 years later and how well they classified these patients at the end of the 2 years. METHODS: Patients were evaluated during 1995-1997 at 7 hospitals in the Brittany region of France. Patients were evaluated at 6-month intervals until November 1999. The diagnosis made by a panel of 5 rheumatologists (P5R) after the last visit was used as the "gold standard." The ACR 1987 criteria for RA were applied prospectively, without taking into account the initial diagnosis. RESULTS: At the last visit (mean +/- SD followup 29.1 +/- 11.8 months; median 30 months), the P5R diagnosed RA in 98 patients. At the last visit, classification by the ACR criteria was satisfactory, and the combination of an office-based rheumatologist's (OBR's) diagnosis of RA and fulfillment of the ACR criteria was sensitive (87%; 85 of 98 RA patients had both) and highly specific (99%; 170 of 172 non-RA patients did not have both). Application of the criteria at the first visit was of limited value for predicting a diagnosis of RA 2 years later. CONCLUSION: After a 2-year followup, the ACR 1987 classification criteria used in combination with an OBR's diagnosis were effective in distinguishing patients with and without RA. The criteria were not useful for predicting RA in patients with arthritis onset within the previous year. Some patients who met the criteria at baseline and after 2 years did not have RA, suggesting that incorporating exclusion criteria may improve the performance of the ACR criteria when used without taking into account the diagnosis by a rheumatologist, particularly in early arthritis.

Ability of hand radiographs to predict a further diagnosis of rheumatoid arthritis in patients with early arthritis.

OBJECTIVE: To evaluate the ability of hand radiographs collected at study inclusion to predict a diagnosis of rheumatoid arthritis (RA) 2 years later, in a cohort of patients with early arthritis. METHODS: We evaluated 270 patients with arthritis of less than one year duration. At the first visit, all patients underwent a standardized evaluation including laboratory tests and radiographs. Followup was 30+/-11.3 mo. The hand radiographs were read by observers blinded to patient data who looked for item 7 of the 1987 ACR criteria for RA and used Sharp's method to score erosions and joint space narrowing. RESULTS: The kappa coefficient for ACR item 7 was < 0.65 for bony decalcification and > 0.8 for erosions. Intra and interobserver correlation coefficients for Sharp score ranged from 0.90 to 0.95. The "erosion" component of ACR item 7 was more specific than the full item 7 (96% versus 87.5%; p = 0.02). Sharp erosion score was not better than the erosion component of item 7 (sensitivity 17%; specificity 96%). CONCLUSION: Regardless of the criterion used, hand radiographs were of limited value to predict which patients would be considered as having RA 2 years later. Diagnostic performance was similar for the "erosions" component of the 1987 ACR item 7 and for Sharp erosion score. The full 1987 ACR item 7 (erosions or bony decalcification) performed less well.

Inhalation exposure to THMs from drinking water in south Taiwan.

Trihalomethanes (THMs) are important disinfection byproducts (DBPs) in drinking water. To understand the magnitude of exposure to THMs for the people in southern Taiwan, models are used to estimate the inhalation exposure associated with drinking water based on raw water quality. Two parts of models are used in this study, one for estimating THM concentration from raw water quality, and one for estimating inhalation exposure to people. Important raw water quality and operational parameters, including TOC, UV254, pH, temperature, chlorine dosage, and water residence time of a major water treatment plant in south Taiwan were collected. An empirical THM formation model was then employed to predict the THM concentration at consumers' dwellings based on the parameters collected. Differences between the predicted results and experimental data were found to be small, indicating that the model is appropriate. The predicted THM concentration distribution was served as input parameters for the exposure models. Three major scenarios associated with probable inhalation exposure of THMs, including shower, pre- and post-cooking activities, and cooking processes, were considered in the exposure models. The model results show that the mean inhalation exposure of THMs for shower, pre- and post-cooking activities, and cooking processes are 26.4, 1.56, 3.29 micrograms/day, respectively. The total inhalation exposure (summation of the three scenarios) was found to be comparable with that for direct ingestion, indicating that inhalation is an important pathway for THM exposure from drinking water.