Risk factors associated with weak and asymmetric handgrip strength in older Chinese adults.

OBJECTIVES: This study sought to investigate the potential risk factors associated with weak and asymmetric handgrip strength (HGS) in older Chinese adults. METHODS: A total of 2702 participants aged ≥65 years from the two waves of data (2011 and 2013) from the China Health and Retirement Longitudinal Study were analyzed. The highest recorded HGS values (Method A) or the average HGS values (Method B) for the dominant hand were used to compute the HGS asymmetry (nondominant HGS/dominant HGS out of 0.9-1.1) and HGS weakness (male <28 kg, female <18 kg). Risk factors associated with the weak and asymmetric HGS were identified by logistic regression analysis. RESULTS: Risk factors associated with weak and asymmetric HGS of varying severity differed between the two methods. Both methods identified age and illiteracy as risk factors for weak HGS with 10%-20% asymmetry. Method A also identified speech impediment, stroke, and sleep duration as additional risk factors. Similarly, both methods identified age, illiteracy, primary school education and below, diabetes, and stroke as risk factors for weak HGS and asymmetry over 30.1%. Method B additionally identified a history of falls as a risk factor. However, apart from age, the risk factors for weak HGS with 20.1%-30% asymmetry differed between the two methods-Method A identified kidney disease, while Method B identified illiteracy and asthma. CONCLUSIONS: The results revealed that risk factors associated with the abnormal HGS in older adults varied based on the methods used to define these conditions.

Genetic typing, based on the 56-kilodalton type-specific antigen gene, of Orientia tsutsugamushi strains isolated from chiggers collected from wild-caught rodents in Taiwan.

Orientia tsutsugamushi is the etiological agent of scrub typhus, a mite-borne, febrile illness that occurs in the Asia-Pacific region. We conducted strain characterization of O. tsutsugamushi isolates from chiggers obtained from rodents based the nucleotide sequence of the 56-kDa outer membrane protein gene. With the use of PCR, a total of 68 DNA sequences of 56-kDa antigen genes were amplified. Phylogenetic analysis revealed that there were at least six definable clusters among the 68 isolates: 37% Karp-related strains (25/68), 27% TA763 strains (18/68), 12% JG-related strains (8/68), 19% Kato-related strains (13/68), 4% divergent strains (3/68), and 1% representing a Gilliam prototype strain (1/68). Overall, the O. tsutsugamushi genotypes exhibited a high degree of diversity, similar to that seen in strains from the rest of the areas where scrub typhus is endemic. Moreover, the 56-kDa protein sequence similarity between O. tsutsugamushi isolates from mites and those from human patients (H. Y. Lu et al., Am. J. Trop. Med. Hyg. 83:658-663, 2010) were striking, thus highlighting potential risk factors for this emerging zoonotic disease.

Automatic Liver Segmentation from CT Images Using Single-Block Linear Detection.

Automatic liver segmentation not only plays an important role in the analysis of liver disease, but also reduces the cost and humanity's impact in segmentation. In addition, liver segmentation is a very challenging task due to countless anatomical variations and technical difficulties. Many methods have been designed to overcome these challenges, but these methods still need to be improved to obtain the desired segmentation precision. In this paper, a fast algorithm is proposed for liver extraction from CT images with single-block linear detection. The proposed method does not require iteration; thus, the computational time and complexity are decreased enormously. In addition, the initialization is not crucial in the algorithm, so the algorithm's robustness and specificity are improved. The experimental evaluation of the proposed method revealed effective segmentation in normal and abnormal (liver hemangioma and liver cancer) abdominal CT images. The average sensitivity, accuracy, and specificity for liver cancer are 96.59%, 98.65%, and 99.03%, respectively. The results of image segmentation approximate the manual segmentation results by the technical doctor. Moreover, our method shows superior flexibility to newly published method with comparable performance. The advantage of our method is verified with experimental results, which is described in detail.

Monitoring of Japanese encephalitis virus infection in mosquitoes (Diptera: Culicidae) at Guandu Nature Park, Taipei, 2002-2004.

Japanese encephalitis virus (JEV) infection in mosquitoes was monitored at Guandu Nature Park in Taipei City from September 2002 to December 2004. In total, 30,386 female mosquitoes consisting of six genera and 14 species were processed for virus in 1,229 pools by using Flavivirus NS5 gene sequences detected by reverse transcription-polymerase chain reaction (PCR) and nested PCR assay. Overall, 101 pools were positive, including 95, 1, 4, and 1 for Culex tritaeniorhynchus Giles, Culex sitiens Wiedemann, Culex rubithoracis (Leicester), and Aedes vexans noctunmus (Theobald), respectively.

Field assessment of Orientia tsutsugamushi infection in small mammals and its association with the occurrence of human scrub typhus in Taiwan.

We conducted an extensive study in Taiwan of Orientia tsutsugamushi (OT) infection in small wild mammals. Field trapping was carried out at six districts in eastern and western Taiwan as well as various offshore islands during the period 2006-2010. A total of 1061 specimens representing 11 rodent species were captured. The presence of OT infection was assessed by indirect immunofluorescence assay and polymerase chain reaction assays of 56-kDa type-specific antigen gene. The chigger infestation rate among the animals was 35% (371/1061). Among these, OT was detected in 64% (238/371) of the chiggers from the infested animals and in the spleens from 273 (34.3%) of 797 animals. Excluding animals in the Suncus murinus group, the antibody positive rate of scrub typhus was 69.1% (477 of 690 of serum samples). The prevalence of OT infection in animals from areas with a low incidence of human cases of scrub typhus was significantly lower than that in rodents obtained from regions with a high incidence of human cases of the disease (44.4%±4.0% vs. 71.2%±9.7%, p<0.001). In Taiwan, the prevalence of OT infection in wild rodents is considerably high and appears to correlate positively with the occurrence of scrub typhus in humans.

Molecular detection and characterization of spotted fever group rickettsiae in Taiwan.

Rickettsioses are emerging infectious diseases caused by rickettsiae in association with arthropods. We report the detection of spotted fever group rickettsiae (SFGR) in Taiwan using molecular methods. Phylogenetic analyses of the 17-kd protein and citrate synthase (gltA) genes showed that SFGR TwKM01 detected in Rhipicephalus haemaphysaloides ticks was most similar to Rickettsia rhipicephali. Three TwKM01 isolates were obtained from three individual R. haemaphysaloides ticks. Small, intracellular, coccobacillary bacteria were found in infected L929 cells using immunofluorescence antibody testing and transmission electron microscopy. Two other SFGRs, TwKM02 and TwKM03, identified in Leptotrombidium chigger mites, were closely related to R. australis and R. felis URRWXCal(2), respectively. The TwKM03 strain was also detected in Ixodes granulatus ticks and widely distributed in Hualien, Kinmen, and Lienchiang counties in Taiwan. The endonucleases MaeII and HhaI selected for restriction fragment length polymorphism analysis of the gltA and 17-kd polymerase chain reaction products, respectively, were useful for genotyping Rickettsia species TwKM01, TwKM02, TwKM03, and other SFGRs. Although their infectivity and pathogenicity for vertebrates are unknown, the finding of SFGRs raises the possibility that bacteria other than Orientia tsutsugamushi, Coxiella burnetii, and R. typhi may be involved in rickettsial diseases in Taiwan.

Sensitive and specific detection of strains of Japanese encephalitis virus using a one-step TaqMan RT-PCR technique.

A rapid, sensitive, and accurate laboratory diagnostic test is needed for distinguishing Japanese encephalitis virus (JEV) from other diseases featuring similar clinical symptoms and also for preventing potential outbreaks. In this study, a TaqMan reverse transcription (RT)-polymerase chain reaction (PCR) assay was developed for rapid detection and quantification of the viral RNA of various JEV strains. A consensus JEV NS3 region was chosen to design the primers and the TaqMan probe. The JEV TaqMan assay used the EZ-rTtH RT-PCR system featuring advantages such as a one-step, high-temperature RT reaction modality and preventing carry-over contamination. The sensitivity of the JEV TaqMan assay for detecting in vitro-transcribed JEV NS3 RNA was estimated to be one to five copies of RNA per reaction. For cultured JE virions, less than 40 plaque forming unit (PFU)/ml of virus load (corresponding to 0.07 PFU/test) could be detected. In addition, the JEV TaqMan assay could detect all seven strains of JEV tested, but provided negative results for nine other flaviviruses and encephalitis viruses tested. The JEV TaqMan assay demonstrated greater sensitivity and specificity than traditional RT-PCR methods as has been previously reported. The application of the JEV TaqMan assay herein has been shown to the sensitive detection of the JEV from both mosquito pools and also JEV-spiking human blood. The assay should be of use in diagnostic laboratory conduct and could be used to replace or complement time-consuming viral-culture methods, thus achieving more rapid, sensitive, and highly specific identification of JEV infection.