Epidemiological, Genetic, and Phenotypic Characteristics of Non-Typhoidal Salmonella in Young Children, as Obtained from a Tertiary Hospital in Guangzhou, China

Gastroenteritis caused by non-typhoidal Salmonella (NTS) is a significant disease in childhood, ranking as the seventh-leading cause of diarrhea mortality in children aged < 5 years. To understand the epidemiological, genetic, and phenotypic characteristics of NTS, 465 anal swabs from children aged < 5 years in a tertiary hospital in Conghua District, Guangzhou, China, were collected from June to October 2021. An average prevalence of 35.27% (164/465) was observed, with whole genome sequencing identifying 11 serotypes, among which Salmonella 1,4,[5],12:i:- was the most prevalent (65.24%, 107/164). Meanwhile, ST34 was found to be the predominant subtype. Children who are breastfed, eat fresh food, and have good hygiene habits show a relatively low prevalence of NTS. Fever is a common symptom that may be caused by NTS infection. Antimicrobial resistance testing revealed that the majority of strains were resistant to tetracycline (83.5%) and ampicillin (82.3%), with multi-drug resistance (MDR) observed in 50.61% (83/164) of all strains tested. The predominant resistance spectrum presents as tetracycline-ampicillin-chloramphenicol-trimethoprim-sulfamethoxazole (30.49%, 50/164). The antimicrobial resistance rates (2.4%, 9.8%, 9.8%, 10.4%, 9.1%, and 3.7%, respectively) of cephalosporins (cefepime, cefuroxime, cefuroxime axetil, ceftriaxone, ceftazidime, and cefoxitin) were low. Therefore, continued surveillance of the prevalence and MDR profiles of NTS, along with the rational use antibiotics, is required. This protocol is significant for preventing further dissemination of NTS and formulating effective prevention and control strategies.

Prevalence of Chromosomally Located blaCTX-M-55 in Salmonella Typhimurium ST34 Isolates Recovered from a Tertiary Hospital in Guangzhou, China

Nontyphoidal Salmonella (NTS) is one of the most prevalent bacterial causes of gastrointestinal infections worldwide. Meanwhile, the detection rate of CTX-M-55 ESBL-positive has increased gradually in China. To identify the molecular epidemiological and genomic characteristics of blaCTX-M-55-carrying nontyphoidal Salmonella (NTS) clinical isolates, a total of 105 NTS isolates were collected from a Chinese tertiary hospital. Antimicrobial susceptibility testing was performed to determine the resistance phenotype. Whole-genome sequencing and bioinformatics analysis were used to determine the antimicrobial resistance genes, serotypes, phylogenetic relationships, and the genetic environment of the blaCTX-M-55 gene. The results showed that among the 22 ceftriaxone resistant isolates, the blaCTX-M-55 was the most common β-Lactamase gene carried by 14 isolates, including serotypes S. Typhimurium (10/14), S. Muenster (2/14), S. Rissen (1/14), and S. Saintpaul (1/14). Phylogenetic analysis shows that 10 blaCTX-M-55-positive S. Typhimurium ST34 isolates were divided into two clusters. The genetic relationship of isolates in each cluster was very close (≤10 cgMLST loci). The blaCTX-M-55 gene was located on the chromosome in 10 isolates, on IncI1 plasmid in three isolates, and IncHI2 plasmid in one isolate. In conclusion, the blaCTX-M-55 gene, mainly located on the chromosome of S. Typhimurium ST34 isolates, was the main driving force associated with the resistance of NTS to cephalosporins. Therefore, close attention to the clonal dissemination of blaCTX-M-55-carrying S. Typhimurium ST34 in clinical settings must be monitored carefully. IMPORTANCE ESCs are the first choice for treating NTS infections. However, ESBLs and AmpC β-lactamases are the most typical cause for ESCs resistance. The CTX-M-55 ESBL-positive rate has gradually increased in the clinic in recent years. At present, the research about blaCTX-M-55-positive Salmonella mainly focuses on the foodborne animals or the environment while less on clinical patients. Thus, this study was carried out for identifying molecular epidemiological and genomic characteristics of blaCTX-M-55-carrying NTS clinical isolates. The results showed that the blaCTX-M-55 gene, mainly located on the chromosome of S. Typhimurium ST34 isolates from Conghua District, was the main driving force associated with the resistance of NTS to cephalosporins. Therefore, our work highlights the importance of monitoring the clonal dissemination of blaCTX-M-55-carrying S. Typhimurium ST34 in clinical settings.

Prevalence, Serotype Distribution and Antimicrobial Resistance of Non-Typhoidal Salmonella in Hospitalized Patients in Conghua District of Guangzhou, China

Salmonella infection is a major public health concern worldwide, has contributed to an increased economic burden on the health systems. Non-typhoidal Salmonella (NTS) is a common cause of bacterial enteritis in humans, causing 93.8 million cases of gastroenteritis globally each year, with 155,000 deaths. Guangzhou city is situated in the south of China and has a sub-tropical climate, the heat and heavy rainfall helps the spread of NTS. However, no information of NTS infection is available in humans in Conghua District, the largest administrative district of Guangzhou. To understand the prevalence, serotype distribution, risk factors and drug resistance of NTS infection in humans in the survey area, an epidemiological investigation was conducted in hospitalized patients in Conghua District in Guangzhou, China. A total of 255 fecal specimens were collected from hospitalized patients (one each), with a questionnaire for each participant, and NTS infection was identified by culture, as well as serotypes confirmed by slide agglutination tests. An average prevalence of 20.39% (52/255) was observed and three serogroups were identified—serogroup B (n = 46), serogroup C1 (n = 4) and serogroup D1 (n = 2). Among them, Salmonella Typhimurium (n = 39) was the most common serotype. Children aged &lt;3 years were observed to have a statistically higher prevalence of NTS infection than adults (25.15% versus 4.65%, P = 0.006); children with artificial feeding had a statistically higher prevalence than those with breastfeeding (30.77% versus 8.33%, P = 0.044). Antimicrobial resistance testing revealed that the majority of strains were resistant to ampicillin (92.16%), as well as 47.06% of all strains were multi-drug resistant. Therefore, it is necessary to continuous monitoring and rational use of antibiotics, which will be helpful to reduce the prevalence of resistant strains. These data will aid in making efficient control strategies to intervene with and prevent occurrence of salmonellosis.

Study on the regulation mechanism of lipopolysaccharide on oxidative stress and lipid metabolism of bovine mammary epithelial cells

The long-term feeding of a high-concentrate diet (the concentrate ratio is greater than 60 %) leads to mammary gland inflammatory response in ruminants and decreased quality in dairy cows and affects the robust development of the dairy industry. The main reason is closely related to elevated lipopolysaccharide (LPS) in the body. In this experiment, a bovine mammary epithelial cell line (MAC-T) was used as a model, and LPS at different concentrations (0 ng/ml, 1 ng/ml, 10 ng/ml, 100 ng/ml, 1000 ng/ml, 10000 ng/ml) was added to the cells. The cell survival rate, oxidative stress indicators, total lipid droplet area, triglyceride content and key genes regulating lipid metabolism were detected by 3-(4,5)-dimethylthiahiazo(-z-y1)-3,5-di-phenytetrazoliumromide (MTT), assay kit, microscope observation and RT-PCR methods to explore the regulatory mechanism of mammary health and milk fat synthesis. The results showed that compared with those of the control group, the survival rates of cells were significantly decreased after 9 h of stimulation with 1000 ng/ml and 10000 ng/ml LPS (P<0.01). The contents of superoxide dismutase (SOD), catalase (CAT) and total antioxidant capacity (T-AOC) in cells were significantly decreased (P<0.05). Compared with that of the control group, the content of malondialdehyde (MDA) in cells was significantly increased (P<0.05) after stimulation with 10000 ng/ml LPS for 9 h. After 9 h of stimulation with 100 ng/ml, 1000 ng/ml and 10000 ng/ml LPS, the total lipid drop area and triglyceride (TG) content of MAC-T cells were significantly decreased (P<0.05). The expression levels of fatty acid synthesis-related genes Acetyl-CoA carboxylase (ACC) and Stearoyl-CoA desaturase 1 (SCD-1) were significantly decreased after 9 h of stimulation with 100 ng/ml, 1000 ng/ml and 10000 ng/ml LPS (P<0.05), while the expression levels of Fatty Acid synthetase (FAS) were significantly decreased after stimulation with 1000 ng/ml and 10000 ng/ml LPS (P<0.05). TG synthesis by the related gene Diacylglycerol acyltransferase-1 (DGAT1) was significantly lower than that of the control group after stimulation with 1000 ng/ml and 10000 ng/ml LPS for 9 h (P<0.05), and Diacylglycerol acyltransferase-2 (DGAT2) also showed a significant decrease after 10000 ng/ml LPS stimulation (P<0.05). In conclusion, adding different concentrations of LPS to MAC-T cells not only led to a decrease in cell activity, resulting in oxidative damage, but also affected fatty acid and TG synthesis, which may ultimately be closely related to the decrease in milk fat synthesis.

Viscoelasticity of 3D actin networks dictated by the mechanochemical characteristics of cross-linkers

In this study, we report a computational investigation on how the mechanochemical characteristics of crosslinking molecules influence the viscoelasticity of three dimensional F-actin networks, an issue of key interest in analyzing the behavior of living cells and biological gels. In particular, it was found that the continuous breakage and rebinding of cross-linkers result in a locally peaked loss modulus in the rheology spectrum of the network, reflecting the fact that maximum energy dissipation is achieved when the driving frequency of the applied oscillating shear becomes comparable to the dissociation/association rate of crosslinking molecules. In addition, we showed that when subjected to constant rate of shear, an actin network can exhibit either strain hardening or softening depending on the ratio between the loading rate and unbinding speed of cross-linkers. A criterion for predicting the transition from softening to hardening was also obtained, in agreement with recent experiments. Finally, significant structural evolution was found to occur in random networks undergoing mechanical "training" (i.e. under a constant applied shear stress over a period of time), eventually leading to a pronounced anisotropic response of the network afterward which again is consistent with experimental observations.

Can deep learning beat numerical weather prediction?

The recent hype about artificial intelligence has sparked renewed interest in applying the successful deep learning (DL) methods for image recognition, speech recognition, robotics, strategic games and other application areas to the field of meteorology. There is some evidence that better weather forecasts can be produced by introducing big data mining and neural networks into the weather prediction workflow. Here, we discuss the question of whether it is possible to completely replace the current numerical weather models and data assimilation systems with DL approaches. This discussion entails a review of state-of-the-art machine learning concepts and their applicability to weather data with its pertinent statistical properties. We think that it is not inconceivable that numerical weather models may one day become obsolete, but a number of fundamental breakthroughs are needed before this goal comes into reach. This article is part of the theme issue 'Machine learning for weather and climate modelling'.

Identification of Uncommon Cryptosporidium viatorum (a Novel Subtype XVcA2G1c) and Cryptosporidium andersoni as Well as Common Giardia duodenalis Assemblages A and B in Humans in Myanmar

Cryptosporidium and Giardia are two important zoonotic intestinal protozoa responsible for diarrheal diseases in humans and animals worldwide. Feces from infected hosts, water and food contaminated by Cryptosporidium oocysts and Giardia cysts as well as predictors such as poverty have been involved in their transmission. Myanmar is one of the world’s most impoverished countries. To date, there are few epidemiological studies of Cryptosporidium and Giardia in humans. To understand the prevalence and genetic characterization of Cryptosporidium spp. and Giardia duodenalis in humans in Myanmar, a molecular epidemiological investigation of the two protozoa was conducted in four villages of Shan State. 172 fecal specimens were collected from Wa people (one each) and identified for the presence of Cryptosporidium spp. and G. duodenalis by sequence analysis of their respective small subunit ribosomal RNA genes. 1.74% of investigated people were infected with Cryptosporidium spp.—C. andersoni (n = 2) and C. viatorum (n = 1) while 11.05% infected with G. duodenalis—assemblages A (n = 6) and B (n = 13). By sequence analysis of 60-kDa glycoprotein gene, the C. viatorum isolate belonged to a novel subtype XVcA2G1c. DNA preparations positive for G. duodenalis were further subtyped. Five of them were amplified and sequenced successfully: different assemblage B sequences (n = 2) at the triosephosphate isomerase (tpi) locus; sub-assemblage AII sequence (n = 1) and identical assemblage B sequences (n = 2) at the β-giardin (bg) locus. This is the first molecular epidemiological study of Cryptosporidium spp. and G. duodenalis in humans in Myanmar at both genotype and subtype levels. Due to unclear transmission patterns and dynamics of Cryptosporidium spp. and G. duodenalis, future research effort should focus on molecular epidemiological investigations of the two parasites in humans and animals living in close contact in the investigated areas, even in whole Myanmar. These data will aid in making efficient control strategies to intervene with and prevent occurrence of both diseases.

Multilocus Sequence Typing of Enterocytozoon bieneusi Isolates From Various Mammal and Bird Species and Assessment of Population Structure and Substructure

Enterocytozoon bieneusi is one of the most common intestinal pathogens in humans and animals. E. bieneusi has been confirmed to be complex microsporidian species. Approximately 500 ITS genotypes of E. bieneusi have been defined. With the establishment and application of multilocus sequencing typing and population genetic tools in E. bieneusi, the studies on these aspects have been carried out worldwide, but little information is available. To understand genetic variation of mini-/micro-satellites and the population structure and substructure of E. bieneusi in northeastern China, 305 E. bieneusi DNA specimens composed of 28 ITS genotypes were from 13 mammal species and five bird species in the investigated areas. They were characterized by nested-PCR amplification and sequencing at four mini-/micro-satellite loci (MS1, MS3, MS4, and MS7). At the MS1, MS3, MS4, and MS7 loci, 153 (50.16%), 131 (42.95%), 133 (43.61%), and 128 (41.97%) DNA specimens were amplified and sequenced successfully with 44, 17, 26, and 24 genotypes being identified, respectively. Multilocus genotypes (MLGs) showed a higher genetic diversity than ITS genotypes. 48 MLGs were produced out of 90 ITS-positive DNA specimens based on concatenated sequences of all the five genetic loci including ITS. Linkage disequilibrium (LD) and limited genetic recombination were observed by measuring LD using both multilocus sequences and allelic profile data, indicating an overall clonal population structure of E. bieneusi in the investigated areas. These data will aid in the longitudinal tracking of the attribution of source of infection/contamination and in elucidating transmission dynamics, and will provide valuable information for making efficient control strategies to intervene with and prevent occurrence of microsporidiosis caused by E. bieneusi among animals and transmission of E. bieneusi from animals to humans in the investigated areas. Phylogenetic and network analyses identified three different subgroups, revealing the presence of host-shaped segregation and the absence of geographical segregation in E. bieneusi population. Meanwhile, the MLGs from zoonotic ITS genotypes were observed to be basically separated from the MLGs from host-adapted ones. Assessment of substructure will have a reference effect on understanding of zoonotic or interspecies transmission of E. bieneusi and evolution direction from zoonotic genotypes to host-adapted genotypes.

A retrospective epidemiological analysis of human Cryptosporidium infection in China during the past three decades (1987-2018)

Background

Cryptosporidiosis is an emerging infectious disease of public health significance worldwide. The burden of disease caused by Cryptosporidium varies between and within countries/areas. To have a comprehensive understanding of epidemiological status and characteristics of human Cryptosporidium infection in China since the first report in 1987, a retrospective epidemiological analysis was conducted by presenting differences in the prevalence of Cryptosporidium by province, year, population, living environment and season and possible transmission routes and risk factors as well as genetic characteristics of Cryptosporidium in humans.

Methodology/Principal findings

A systematic search was conducted to obtain epidemiological papers of human Cryptosporidium infection/cryptosporidiosis from PubMed and Chinese databases. Finally, 164 papers were included in our analysis. At least 200,054 people from 27 provinces were involved in investigational studies of Cryptosporidium, with an average prevalence of 2.97%. The prevalence changed slightly over time. Variable prevalences were observed: 0.65–11.15% by province, 1.89–47.79% by population, 1.77–12.87% and 0–3.70% in rural and urban areas, respectively. The prevalence peak occurred in summer or autumn. Indirect person-to-person transmission was documented in one outbreak of cryptosporidiosis in a pediatric hospital. 263 Cryptosporidium isolates were obtained, and seven Cryptosporidium species were identified: C. hominis (48.3%), C. andersoni (22.43%), C. parvum (16.7%), C. meleagridis (8.36%), C. felis (3.04%), C. canis (0.76%) and C. suis (0.38%).

Conclusions/Significances

This systematic review reflects current epidemiological status and characteristics of Cryptosporidium in humans in China. These data will be helpful to develop efficient control strategies to intervene with and prevent occurrence of human Cryptosporidium infection/cryptosporidiosis in China as well as have a reference effect to other countries. Further studies should focus on addressing a high frequency of C. andersoni in humans and a new challenge with respect to cryptosporidiosis with an increasing population of elderly people and patients with immunosuppressive diseases.

Cryptosporidium is a major cause of diarrheal disease in humans globally. Due to the lack of effective drug treatment and vaccine prevention against cryptosporidiosis, it is particularly important to develop efficient control strategies to intervene with and prevent Cryptosporidium infection in humans. The present review presented and analyzed epidemiological status and characteristics of Cryptosporidium infection in humans in China since the first report in 1987. To date, epidemiological investigations of Cryptosporidium infecion have been carried out in different populations in 27 provinces, autonomous regions, and municipalities. Average prevalence of Cryptosporidium was 2.97% (5,933/200,054). Like other infectious disease, due to poor sanitation conditions in rural areas, people living in rural areas had a significantly higher prevalence of Cryptosporidium (1.77–12.87%) than those living in urban areas (0–3.70%). Seven Cryptosporidium species were identified, including C. hominis, C. andersoni, C. parvum, C. meleagridis, C. felis, C. canis and C. suis. This retrospective epidemiological analysis indicates wide geographical distribution of human Cryptosporidium infection/cryptosporidiosis in China.

First identification and genotyping of Enterocytozoon bieneusi in humans in Myanmar

Background

Intestinal pathogen infections are widespread among impoverished populations. Enterocytozoon bieneusi is the most common pathogen of intestinal microsporidian species in humans worldwide. However, no epidemiological information is available on E. bieneusi infection in humans in Myanmar. The present study comprised the first identification and genotyping of E. bieneusi in humans conducted in Myanmar.

Results

A total of 172 fecal specimens were collected from the Wa people (one each) in four villages of Pangsang Township of the Matman District of Shan State, Myanmar, and each participant completed a questionnaire. E. bieneusi was identified and genotyped using polymerase chain reaction (PCR) and sequence analysis of the internal transcribed spacer (ITS) region of the ribosomal RNA (rRNA) gene. The average prevalence of E. bieneusi was 8.72% (15/172), ranging from 3.85 to 13.89% by village. E. bieneusi infection was not related to any of the risk factors studied. Six genotypes were identified, comprising two known genotypes Peru6 (n = 10) and D (n = 1) and four novel genotypes (MMR23, MMR25, MMR86, and MMR87) (one each), and two people infected with genotype Peru6 were from the same family. A phylogenetic analysis based on a neighbor-joining tree of the ITS sequences of E. bieneusi indicated that all the six genotypes were clustered into group 1.

Conclusions

This is the first identification and genotyping of E. bieneusi in humans in Myanmar. The observations that the two people infected with genotype Peru6 were from the same family, and that all six genotypes obtained in the present study fell into zoonotic group 1, showed the potential for anthropogenic and zoonotic transmissions. The present data argue for the importance of epidemiological control and prevention from medical sectors.

Prevalence and subtype distribution of Blastocystis in ethnic minority groups on both sides of the China-Myanmar border, and assessment of risk factors

Blastocystis is one of the most common intestinal parasites in humans worldwide. To understand its prevalence and to explore the risk factors for Blastocystis in humans in developing countries, a molecular epidemiological investigation of Blastocystis was conducted in ethnic minority groups on both sides of the China-Myanmar border. A total of 461 fecal specimens were collected from 289 Yao people in China and 172 Wa people in Myanmar, together with a questionnaire for each participant. Based on sequence analysis of the partial small subunit of ribosomal RNA (SSU rRNA) gene (barcode region or 260 bp region), an average prevalence of 6.29% (29/461) was observed, with 4.50% (13/289) in Yao people and 9.30% (16/172) in Wa people. Twenty-two Blastocystis isolates were successfully subtyped by sequence analysis of the barcode region. Three subtypes were identified: ST1 (n = 7), ST3 (n = 13) and ST4 (n = 2). A statistical difference in the prevalence of Blastocystis was only observed between children (12.37%, 12/97) and adults (4.95%, 16/323), and between not washing hands (11.02%, 14/127) and washing hands (4.76%, 15/315) after using toilets, emphasizing the importance and necessity of health education in people in the investigated areas, especially in children.

First survey of Enterocytozoon bieneusi and dominant genotype Peru6 among ethnic minority groups in southwestern China's Yunnan Province and assessment of risk factors

Background

Enterocytozoon bieneusi is the most common microsporidian species causing diarrhea and other intestinal disorders in humans and animals. Like other infectious diseases, microsporidiosis usually disproportionately affects poor populations. In China, some ethnic minority areas remain poor. Currently, no information of E. bieneusi infection is available in minority populations. The present aims were to understand occurrence and genetic characterizations of E. bieneusi in ethnic minority groups from a poverty-stricken ethnic township in Yunnan Province, and to assess risk factors for E. bieneusi infection.

Methodology/Principal findings

289 fecal specimens were collected from Yao people (one specimen each) with and without diarrhea, in Yunnan Province. E. bieneusi was identified and genotyped by PCR and sequence analysis of the ITS region of the rRNA gene. An average prevalence of 8.30% (24/289) was observed and four genotypes were identified—genotype Peru6 (n = 21) and three novel genotypes (one each). Genotype Peru6 was detected in two family members in each of three families. In a phylogenetic analysis, all of four genotypes fell into group 1 with zoonotic potential. The people owning individual pit toilets had a statistically higher prevalence of E. bieneusi (16.67%, 12/72) than those using public pit toilets (6.06%, 12/198).

Conclusions/Significance

This is the first report on occurrence and genetic characteristics of E. bieneusi in ethnic minority groups in China. Genotype Peru6 was found in humans in China for the first time and showed dominance in Yao people. The same genotype was found in some family members and all the genotypes fell into group 1, suggesting the possibility of anthroponotic and zoonotic transmissions. The majority (83.33%, 20/24) of E. bieneusi positive individuals did not present diarrhea. In any case, it is important to recognize their existence and the importance that asymptomatic individuals to E. bieneusi may have from an epidemiological point of view, as transmitters of this pathogen. The analysis of risk factors provides scientific evidence for the development of effective strategies for prevention and control of E. bieneusi infection.

Enterocytozoon bieneusi is the most prevalent opportunistic microsporidian species causing diarrhea in humans and animals worldwide. Due to frequent occurrence of chronic or life-threatening diarrhea mainly in HIV/AIDS patients and others patients such as elderly people, transplant recipients and cancer patients, epidemiological studies of E. bieneusi focus on this susceptible population. Asymptomatic carriers of E. bieneusi are often neglected, and their role in the transmission of this microorganism is not paid enough attention. The prevalence of E. bieneusi is also actually related to the geographical locations, the populations and the socioeconomic conditions. The infectious diseases usually disproportionately affect poor populations. In China, although total economy has developed rapidly, there is the regional imbalance in economic development and some minority areas remain poor. Thus, we carried out a molecular epidemiology survey of E. bieneusi among 289 Yao people with and without diarrhea from a poverty-stricken ethnic township. We identified E. bieneusi in 8.30% (24/289) of people, with the majority (83.33%, 20/24) of positive individuals having no diarrhea. Meanwhile, zoonotic genotype Peru6 was found to be dominant in infected people. Our study emphasizes the importance and significance in epidemiological surveys of E. bieneusi in non-diarrheal people and assessment of risk factors for E. bieneusi infection.

A human case of Dioctophyma renale (giant kidney worm) accompanied by renal cancer and a retrospective study of dioctophymiasis

Due to the rarity of human cases and the nonspecific clinical symptoms of dioctophymiasis, Dioctophyma renale infection is not well recognized and is easily neglected or misdiagnosed. Recently, we diagnosed a human case of dioctophymiasis accompanied by renal cancer. To enhance the understanding of human dioctophymiasis, this case is presented here, and a retrospective study of this disease was conducted based on relevant papers screened from PubMed and three Chinese databases. In the end, 32 papers describing 37 human cases of dioctophymiasis were assessed. These cases were distributed in ten countries of Asia, Europe, North America and Oceania, with the highest number in China (n = 22). The majority of the cases occurred in adults (91.9%, 34/37) and involved the kidneys (83.8%, 31/37). Ectopic parasitism mainly occurred in subcutaneous tissue (83.3%, 5/6). A proportion of 45.9% (17/37) of individuals had a history of eating raw or undercooked fish or frogs. The main clinical manifestations of human dioctophymiasis were loin pain (59.5%) and hematuria (59.5%). All the cases were diagnosed based on the morphological characteristics of eggs or adults in urine or tissue sections. Currently, there is no strictly defined therapeutic approach. This is the first retrospective analysis of human cases of dioctophymiasis. These review data will deepen our understanding of dioctophymiasis and help avoid misdiagnosis in clinical practice.

Distribution and genetic diversity of Blastocystis subtypes in various mammal and bird species in northeastern China

Background

Blastocystis is one of the most common intestinal parasites in humans and animals worldwide. At least 17 subtypes have been identified in mammals and birds. In China, although some studies have reported the occurrence of Blastocystis in humans and animals, our understanding of the role of animals in the transmission of human blastocystosis is only superficial due to a paucity of available molecular data. The aim of the present study was to understand infection rates of Blastocystis and the distribution and genetic diversity of subtypes in various mammal and bird species in northeastern China, as well as to assess the zoonotic potential of Blastocystis isolates.

Methods

A total of 1265 fresh fecal specimens (1080 from ten mammal species and 185 from eight bird species) were collected in Heilongjiang, Liaoning and Jilin provinces of China. Each specimen was examined for the presence of Blastocystis by PCR amplification and sequence analysis of the partial SSU rRNA gene.

Results

Fifty-four specimens (4.3%) were positive for Blastocystis. Birds (7.0%) had a higher infection rate of Blastocystis than mammals (3.8%). Blastocystis was found in seven mammal species, reindeer (6.7%), sika deer (14.6%), racoon dogs (7.5%), Arctic foxes (1.9%), dogs (2.9%), rats (3.7%) and rabbits (3.3%), as well as three bird species, pigeons (2.1%), chickens (13.0%) and red crowned cranes (14.0%). Eight subtypes were identified including ST1 (n = 5), ST3 (n = 3), ST4 (n = 13), ST6 (n = 8), ST7 (n = 6), ST10 (n = 13), ST13 (n = 4) and ST14 (n = 2). 64.8% (35/54) of Blastocystis isolates belonged to potentially zoonotic subtypes.

Conclusions

To our knowledge, this is the first report of Blastocystis in reindeer (ST10 and ST13), rabbits (ST4), racoon dogs (ST3) and Arctic foxes (ST1, ST4 and ST7). The findings of potentially zoonotic subtypes suggest that the animals infected with Blastocystis might pose a threat to human health. These data will improve our understanding of the host range and genetic diversity of Blastocystis, and also help develop efficient control strategies to intervene with and prevent the occurrence of human blastocystosis in the investigated areas.

Electroacupuncture for patients with refractory functional dyspepsia: A randomized controlled trial

BACKGROUND

To test the efficacy of electroacupuncture for patients with refractory functional dyspepsia (FD).

METHODS

A 24-week, 2-arm, single-blind, randomized controlled trial was conducted at three hospitals in China. Patients with refractory FD were randomly assigned to receive 20 sessions of authentic or sham electroacupuncture in a treatment duration of 4 weeks. The primary outcome was complete absence of dyspeptic symptoms at 16 weeks after initiation of acupuncture (week 16). The secondary outcomes included adequate relief of dyspeptic symptoms, Leeds Dyspepsia Questionnaire (LDQ), Nepean Dyspepsia Index (NDI), and adverse events. Intention-to-treat analysis was performed.

KEY RESULTS

Two hundred patients were included, of which 196 (98%) completed follow-up data at week 24. At week 16, 17 (17%) patients in the authentic electroacupuncture group vs 6 (6%) patients in the sham group achieved the primary outcome (P = .014). Sixty-two (62%) patients had adequate relief in the authentic electroacupuncture group, as compared to 22 (22%) in the sham group (P = .001). The scores of LDQ and NDI were significantly improved in both groups at week 16, and patients in the authentic electroacupuncture group have more improvements (LDQ, mean difference, -2.2, 95% confidence interval, -2.3 to -2.1, P < .001; NDI, -7.3, -10.5 to -4.2, P < .001). Results were similar for all the outcomes assessed at week 24. No serious adverse events were reported in both groups.

CONCLUSION

Acupuncture efficaciously improves dyspeptic symptoms in patients with refractory FD.

A Novel Finding: Macrophages Involved in Inflammation Participate in Acute Aortic Dissection Complicated with Acute Lung Injury

BACKGROUND

Little is known about the pathogenesis of acute lung injury (ALI) complicated with acute aortic dissection (AAD).

OBJECTIVE

We aim to investigate the roles of macrophages-derived matrix metalloproteinase 9 (MMP9) in the development of ALI complicated with AAD and factors involved in the recruitment of macrophages.

METHODS

This study included three parts: (i) Determination of serum MMPs, angiotensin II (AngII) and MCP-1 in patients with AAD complicated with ALI or AAD only, non-ruptured chronic aortic aneurysm patients or healthy volunteers using ELISA method. (ii) A novel AAD complicated with ALI model was established by infusing angiotensin II (AngII) to immature rats treated with β-aminopropionitrile monofumarate (BAPN) to identify the potential roles of MMP9 and MCP-1 in AAD complicated with ALI. (iii) Cultured pulmonary microvascular endothelial cell (PMVEC) line was used to investigate how AngII was involved in the release of MCP-1 in rat pulmonary vascular endothelial cells.

RESULTS

Serum MMP9, AngII and MCP-1 were remarkably elevated in patients with AAD complicated with ALI. The MMP9 expressed in pulmonary tissues was derived from macrophages. In the animal model, the release of MMP9 from macrophages finally resulted in ALI, while inhibition of MMP9 and MCP-1 contributed to decreased incidence of AAD complicated with ALI. In vitro experiments indicated that AngII triggered overexpression of MCP-1 in PMVECs by activating NF-κB signaling pathway.

CONCLUSION

AAD complicated with ALI is highly associated with the macrophages infiltrating the pulmonary interstitial tissue and released MMP9 in response to angiotensin II. MCP-1 is closely related to the recruitment of macrophages.

Ventilation inhomogeneity in obstructive lung diseases measured by electrical impedance tomography: a simulation study

Electrical impedance tomography (EIT) has mostly been used in the Intensive Care Unit (ICU) to monitor ventilation distribution but is also promising for the diagnosis in spontaneously breathing patients with obstructive lung diseases. Beside tomographic images, several numerical measures have been proposed to quantitatively assess the lung state. In this study two common measures, the 'Global Inhomogeneity Index' and the 'Coefficient of Variation' were compared regarding their capability to reflect the severity of lung obstruction. A three-dimensional simulation model was used to simulate obstructed lungs, whereby images were reconstructed on a two-dimensional domain. Simulations revealed that minor obstructions are not adequately recognized in the reconstructed images and that obstruction above and below the electrode plane may result in misleading values of inhomogeneity measures. EIT measurements on several electrode planes are necessary to apply these measures in patients with obstructive lung diseases in a promising manner.

Top 50 Landmarks in Sentinel Lymph Node Imaging: A Bibliometric Analysis

Bibliometric analysis can be utilized to identify the most influential literature and track the trajectory of the research development in a given area. The purpose of this study is to summarize the top 50 most-cited landmarks and to examine the recent advances in the field of sentinel lymph node imaging. Web of Science was searched to create a database of all English language scientific journals. This search was then cross referenced with a similar search term query of Scopus to identify articles that may have been missed on the initial search. Articles were ranked by citation counts and screened by two independent reviewers. Citations for the top 50 papers ranged from 2725 to 163 with a median of 240. 10 papers were cited more than 500 times. The articles were published between 1993 - 2009 across 23 journals. Our study identifies intellectual milestones in Sentinel Lymph Node Imaging research, reflecting on the characteristics and quality of the most highly cited literature, and provides a list of the most influential references related to SLNI.

Compensation for large thorax excursions in EIT imaging

Besides the application of EIT in the intensive care unit it has recently also been used in spontaneously breathing patients suffering from asthma bronchiole, cystic fibrosis (CF) or chronic obstructive pulmonary disease (COPD). In these cases large thorax excursions during deep inspiration, e.g. during lung function testing, lead to artifacts in the reconstructed images. In this paper we introduce a new approach to compensate for image artifacts resulting from excursion induced changes in boundary voltages. It is shown in a simulation study that boundary voltage change due to thorax excursion on a homogeneous model can be used to modify the measured voltages and thus reduce the impact of thorax excursion on the reconstructed images. The applicability of the method on human subjects is demonstrated utilizing a motion-tracking-system. The proposed technique leads to fewer artifacts in the reconstructed images and improves image quality without substantial increase in computational effort, making the approach suitable for real-time imaging of lung ventilation. This might help to establish EIT as a supplemental tool for lung function tests in spontaneously breathing patients to support clinicians in diagnosis and monitoring of disease progression.

Four trace elements in pregnant women and their relationships with adverse pregnancy outcomes

OBJECTIVE

Lack of trace elements during pregnancy is detrimental to maternal and fetal health. Our aim is to study the changes in trace element levels in Chinese pregnant women and their association with adverse pregnancy outcomes.

PATIENTS AND METHODS

1568 cases of Chinese pregnant women in remote areas were collected for a prospective cohort study. Serum copper, zinc, calcium and iron levels were measured at pre-pregnancy, 1st trimester (7w-12w), 2nd trimester (24w-28w) and 3rd trimester (35w-40w).

RESULTS

(1) Serum copper levels was significantly higher after pregnancy than before, calcium and iron levels decreased, but zinc levels did not change significantly. (2) Copper and zinc deficiency in pregnant women was not a common finding, but lack of iron and calcium was frequently encountered; iron deficiency was especially common in the 3rd trimester (42.27%). (3) Serum zinc and iron levels in patients who either had a miscarriage or a preterm delivery were significantly lower than in the control group (p < 0.05). In patients with premature rupture of membranes, serum zinc levels were significantly lower (p < 0.05). In patients with intrauterine growth restriction (IUGR), serum copper, zinc, calcium and iron were significantly lower (p < 0.05).

CONCLUSIONS

Trace elements is closely associated with fetal growth and development during pregnancy. Deficiency can lead to adverse pregnancy outcomes. Therefore, we should have a reasonable diet, replenish trace elements, therefore reducing the occurrence of adverse pregnancy outcomes.

Is microplegia really superior to standard blood cardioplegia? The results from a meta-analysis

Background:

Microplegia (whole blood cardioplegia with reduced volume) retains all the advantages of blood cardioplegia (such as superior oxygen-carrying capacity, better osmotic properties and antioxidant capability, etc.) without the potential disadvantages of hemodilution (such as myocardial edema). We sought to perform a systematic review and meta-analysis to compare microplegia and standard blood cardioplegia on the cardioprotective effects for patients undergoing coronary artery bypass grafting (CABG).

Methods:

MEDLINE, EMBASE and the Cochrane Central Register of Controlled Trials were searched for relevant controlled trials published in English, from their inception up to May 15th, 2013. Data on low output syndrome, spontaneous return to sinus rhythm, volume of cardioplegia and perioperative myocardial infarction were analyzed.

Results:

Five studies, totaling 296 patients, were included out of 77 retrieved citations. The microplegia group used less volume of cardioplegia (WMD, -514.79 ml, 95%CI: -705.37 ml to -324.21 ml) when compared with the standard blood cardioplegia group. There were no statistical differences in the incidence of low output syndrome (RR, 0.95, 95%CI: 0.55 to 1.62), spontaneous return to sinus rhythm (RR, 1.64, 95%CI: 0.61 to 4.41) and perioperative myocardial infarction (RR, 0.62, 95%CI: 0.19 to 2.08).

Conclusions:

Microplegia was associated with less volume of cardioplegia, whereas the incidence of spontaneous return to sinus rhythm and perioperative myocardial infarction were similar, but large controlled randomized trials are still needed to confirm this.

A cultured endophyte community is associated with the plant Clerodendrum inerme and antifungal activity

Fungal endophytes live in the inner tissues of Clerodendrum inerme and may be significant resources for new chemicals in drug discovery. A total of 242 endophytic fungi were recovered from 602 sample segments of C. inerme; 66 were purified. The 66 fungi belonging to 16 taxa and 11 genera (Alternaria, Nigrospora, Bartalinia, Pestalotiopsis, Fusarium, Mycoleptodiscus, Trichoderma, Phomopsis, Diaporthe, Lasiodiplodia, and Curvularia) were identified by morphological characteristics and fungal internal transcribed spacer sequences. The most abundant genera were Alternaria and Lasiodiplodia. Some of the endophytes exhibited tissue specificity. The colonization frequencies of endophytes in the stems were evidently higher than those in the roots and leaves. The crude ethyl acetate extracts were tested against 6 endophytes isolated from C. inerme. Three of 10 (33.3%) endophytes, which were identified as Phomopsis sp, Curvularia sp, and Mycoleptodiscus sp, displayed distinct antifungal activity against ≥3 tested fungi. To our knowledge, this is the first report of an endophytic community associated with C. inerme in China and its antifungal activity in vitro.

Ketamine used as an acesodyne in human breast cancer therapy causes an undesirable side effect, upregulating anti-apoptosis protein Bcl-2 expression

Ketamine is a dissociative anesthetic agent that has been widely used in surgery and for relieving pain in chronic cancer patients. We applied ketamine to breast cancer cell line MDA-MB-231 to detect the effect of treatment and molecular mechanisms involved. We found that ketamine can upregulate the level of anti-apoptosis protein Bcl-2, which promotes breast cancer cell invasion and proliferation. Knockdown of Bcl-2 could inhibit the increase of Bcl-2 and reduce the invasion and proliferation caused by ketamine in human breast cancer cells. Our findings provide new insight into the effects of ketamine in cancer treatment; we suggest that ketamine, which has been widely used in cancer operations and for relieving pain in chronic cancer patients, may be not the best choice because it can worsen the cancer through promotion of anti-apoptosis.

Cell death/proliferation roles for nc886, a non-coding RNA, in the protein kinase R pathway in cholangiocarcinoma

We have recently identified nc886 (pre-miR-886 or vtRNA2-1) as a novel type of non-coding RNA that inhibits activation of protein kinase R (PKR). PKR's pro-apoptotic role through eukaryotic initiation factor 2 α (eIF2α) phosphorylation is well established in the host defense against viral infection. Paradoxically, some cancer patients have elevated PKR activity; however, its cause and consequence are not understood. Initially, we evaluated the expression of nc886, PKR and eIF2α in non-malignant cholangiocyte and cholangiocarcinoma (CCA) cells. nc886 is repressed in CCA cells and this repression is the cause of PKR's activation therein. nc886 alone is necessary and sufficient for suppression of PKR via direct physical interaction. Consistently, artificial suppression of nc886 in cholangiocyte cells activates the canonical PKR/eIF2α cell death pathway, suggesting a potential significance of the nc886 suppression and the consequent PKR activation in eliminating pre-malignant cells during tumorigenesis. In comparison, active PKR in CCA cells does not induce phospho-eIF2α nor apoptosis, but promotes the pro-survival nuclear factor-κB pathway. Thus, PKR has a dual life or death role during tumorigenesis. Similarly to the CCA cell lines, nc886 tends to be decreased but PKR tends to be activated in our clinical samples from CCA patients. Collectively from our data, we propose a tumor surveillance model for nc886's role in the PKR pathway during tumorigenesis.

Quantitative assessment of optic nerve head morphology and retinal nerve fibre layer in non-arteritic anterior ischaemic optic neuropathy with optical coherence tomography and confocal scanning laser ophthalmoloscopy

BACKGROUND/AIMS

To compare the optic disc parameters between patients with non-arteritic anterior ischaemic optic neuropathy (NAION) and normal controls, using optical coherence tomography (OCT) and Heidelberg Retinal Tomograph III (HRT), and to evaluate the structure-function relationship in NAION eyes.

METHODS

Both eyes of 22 patients with typical unilateral NAION of > or =6 months' duration and 52 eyes from 52 randomly selected normal subjects underwent Humphrey visual field (HVF) examination and measurement of optic disc and retinal nerve fibre layer thickness (RNFLT).

RESULTS

For the NAION-affected eyes, NAION fellow eyes and normal controls, the ocular magnification-corrected OCT disc areas were respectively 1.849 (SD 0.343) mm(2), 1.809 (0.285) mm(2) and 1.964 (0.386) mm(2); the cup areas were 0.246 (0.187) mm(2), 0.172 (0.180) mm(2) and 0.469 (0.332) mm(2). On HRT, the disc areas were 2.11 (0.38) mm(2), 2.06 (0.40) mm(2) and 2.16 (0.42) mm(2); and the cup areas were 0.28 (0.34) mm(2), 0.25 (0.18) mm(2) and 0.48 (0.32) mm(2). On both OCT and HRT, the cup areas and cup-disc area ratios (CDAR) of both eyes of NAION patients were significantly smaller than controls (p< or =0.01), but the disc areas were not (p> or =0.21). There was a significant correlation between HVF mean deviation and OCT RNFLT (r = 0.44, p = 0.04) but not with HRT RNFLT (p = 0.30) in NAION-affected eyes.

CONCLUSION

NAION patients have smaller optic cups and CDARs in both eyes compared with controls. A larger sample size is necessary to demonstrate if disc size affects the risk of developing NAION. The NAION-affected eyes' OCT RNFLT correlated with HVF mean deviation but the HRT RNFLT did not.

KATP channels depress force by reducing action potential amplitude in mouse EDL and soleus muscle

Although ATP-sensitive K+ (KATP) channel openers depress force, channel blockers have no effect. Furthermore, the effects of channel openers on single action potentials are quite small. These facts raise questions as to whether 1) channel openers reduce force via an activation of KATP channels or via some nonspecific effects and 2) the reduction in force by KATP channels operates by changes in amplitude and duration of the action potential. To answer the first question we tested the hypothesis that pinacidil, a channel opener, does not affect force during fatigue in muscles of Kir6.2-/- mice that have no cell membrane KATP channel activity. When wild-type extensor digitorum longus (EDL) and soleus muscles were stimulated to fatigue with one tetanus per second, pinacidil increased the rate at which force decreased, prevented a rise in resting tension, and improved force recovery. Pinacidil had none of these effects in Kir6.2-/- muscles. To answer the second question, we tested the hypothesis that the effects of KATP channels on membrane excitability are greater during action potential trains than on single action potentials, especially during metabolic stress such as fatigue. During fatigue, M wave areas of control soleus remained constant for 90 s, suggesting no change in action potential amplitude for half of the fatigue period. In the presence of pinacidil, the decrease in M wave areas became significant within 30 s, during which time the rate of fatigue also became significantly faster compared with control muscles. It is therefore concluded that, once activated, KATP channels depress force and that this depression involves a reduction in action potential amplitude.

Crescent oligoamides: from acyclic "macrocycles" to folding nanotubes

Oligoarylamides whose backbones are rigidified by intramolecular hydrogen bonds (H-bonds) are found to adopt well-defined conformations in both solution and solid state. Depending on the length of their backbones, these folding oligoamides are crescents, broken macrocycles, or helices. A large (approximately 10 A) interior cavity is associated with the "macrocycles" and helices. The folded conformations are independent of chain length and are found in both nonpolar and polar solvents. This strategy is being extended to the construction of folding acyclic "macrocycles" and nanotubes with larger tubular cavities.

Stable three-center hydrogen bonding in a partially rigidified structure

The three-center hydrogen bond in diaryl amide 1 was examined by IR and 1H NMR spectroscopy, X-ray crystallography, and ab initio calculations. By comparing 1 with its structural isomers 2, 3 and 4, and with its conformational isomers 1a-c, it was found that the two two-center components of the three-center interaction reinforce each other, that is, the enhanced stability of the three-center hydrogen bond is a result of positive cooperativity between the two components. Substituents not involved in hydrogen bonding have little effect on the strength of the two- and three-center hydrogen bonds. To our knowledge, this is the first three-center hydrogen-bonding system that has been shown to exhibit positive cooperativity. Ab initio calculations of the geometries, vibrational modes, and 1H NMR chemical shifts also support the experimental findings. These results have provided a new insight into the three-center intramolecular hydrogen bonding in a partially rigidified structure and have provided a reliable motif for designing stably folded structures.

Sequence Specificity of Hydrogen-Bonded Molecular Duplexes

Hydrogen-bonded molecular duplexes, 1.3 and 1.4, each of which contains a mismatched binding site (acceptor-to-acceptor in 1.3, and donor-to-donor in 1.4), were designed and synthesized based on duplex 1.2. One- and two-dimensional NMR studies demonstrated that, despite their single mismatched binding sites, the backbones of duplexes 1.3 and 1.4 still stayed in register through the formation of the remaining five H-bonds. The backbones of 1.3 and 1.4 adjusted to the presence of the mismatched binding sites by slightly twisting around these sites, which alleviate any head-on repulsive interactions between two H-bond donors (amide O) or between two acceptors (amide H). After 1 equiv of single strand 2, which forms a perfectly matched duplex 1.2 with single strand 1, was added into the solution of either 1.3 or 1.4, only 1.2 and single strand 3 or 4, were detected. Isothermal titration calorimetry (ITC, in chloroform containing 5% DMSO) indicated that duplexes 1.3 and 1.4 were significantly (>40 times) less stable than the corresponding perfectly hydrogen-bonded duplex 1.2. These NMR and ITC results indicate that the pairing of two complementary single strands is not affected by another very similar single strand that contains only one wrong H-bond donor or acceptor, which demonstrates that the self-assembly of this class of H-bonded duplexes is a highly sequence-specific process. The role of these H-bonded duplexes as predictable and programmable molecular recognition units for directing intermolecular interactions has thus been established.

Structural analysis of the binding modes of minor groove ligands comprised of disubstituted benzenes

Two-dimensional homonuclear NMR was used to characterize synthetic DNA minor groove-binding ligands in complexes with oligonucleotides containing three different A-T binding sites. The three ligands studied have a C(2) axis of symmetry and have the same general structural motif of a central para-substituted benzene ring flanked by two meta-substituted rings, giving the molecules a crescent shape. As with other ligands of this shape, specificity seems to arise from a tight fit in the narrow minor groove of the preferred A-T-rich sequences. We found that these ligands slide between binding subsites, behavior attributed to the fact that all of the amide protons in the ligand backbone cannot hydrogen bond to the minor groove simultaneously.

[Classification for two isolates of Microbispora producing immunosuppressants]

Two strains named SIPI-226 and SIPI-207 producing immunosuppressants were isolated from soil samples collected in park of Wuxi city in China. Identification was done by morphological observation, chemical analysis and nucleic acid ribotyping and 16S rRNA sequence. Two strains contain meso-diaminopimelic acid in cell walls, Type PIV phospholipids, a lack of mycolic acids, MK-9(H0, H2, H4) menaquinones and G + C content of 68.3% to 69.4%, and two strains have 97.2% to 98.6% homology in 16S rRNA gene sequences, and the DNA homology by Ribotyping are 53% to 70%, but differ from seven other mesophilic Microbispora rosea strains. It could be concluded that these two strains represented two new subspecies in the genus of Microbispora rosea. We designated the strains as Microbispora rosea subsp. wuxiensis and Microbispora rosea subsp. yuantouzhuensis. The type strains of M. rosea subsp. wuxiensis and M. rosea subsp. yuantouzhuensis are SIPI-226 and SIPI-207, respectively.

Genomic organization and transcriptional regulation of human Apo2/TRAIL gene

Apo2L, or TRAIL, is a type II integral membrane protein belonging to the TNF family which induces apoptotic cell death in a variety of human tumor cells. Apo2L is expressed in many tissues, suggesting that it is nontoxic to normal cells. We found that Apo2L mRNA was induced by interferon (IFN)-alpha and -beta, but not -gamma, in Jurkat cells. To gain a better understanding of the molecular mechanisms that regulate expression of Apo2L, we have characterized the organization of the human Apo2L gene and its promoter region. The Apo2L gene spans approximately 20 kb and is composed of five exons. The 1.2-kb Apo2L promoter region upstream of the translation initiation codon was cloned, its transcription start site defined, and several putative transcription factor binding sites identified. Luciferase reporter constructs were transfected into Jurkat cells and shown to be induced by IFNs. Deletion analysis indicates that the Apo2L promoter region between nucleotides 126 and 33 upstream of the transcriptional start site controls the expression of the Apo2L gene following IFN-beta treatment.

A K(ATP) channel deficiency affects resting tension, not contractile force, during fatigue in skeletal muscle

The objective of this study was to determine how an ATP-sensitive K(+) (K(ATP)) channel deficiency affects the contractile and fatigue characteristics of extensor digitorum longus (EDL) and soleus muscle of 2- to 3-mo-old and 1-yr-old mice. K(ATP) channel-deficient mice were obtained by disrupting the Kir6.2 gene that encodes for the protein forming the pore of the channel. At 2-3 mo of age, the force-frequency curve, the twitch, and the tetanic force of EDL and soleus muscle of K(ATP) channel-deficient mice were not significantly different from those in wild-type mice. However, the tetanic force and maximum rate of force development decreased with aging to a greater extent in EDL and soleus muscle of K(ATP) channel-deficient mice (24-40%) than in muscle of wild-type mice (7-17%). During fatigue, the K(ATP) channel deficiency had no effect on the decrease in tetanic force in EDL and soleus muscle, whereas it caused a significantly greater increase in resting tension when compared with muscle of wild-type mice. The recovery of tetanic force after fatigue was not affected by the deficiency in 2- to 3-mo-old mice, whereas in 1-yr-old mice, force recovery was significantly less in muscle of K(ATP) channel-deficient than wild-type mice. It is suggested that the major function of the K(ATP) channel during fatigue is to reduce the development of a resting tension and not to contribute to the decrease in force. It is also suggested that the K(ATP) channel plays an important role in protecting muscle function in older mice.

Apo2 ligand/TNF-related apoptosis-inducing ligand and death receptor 5 mediate the apoptotic signaling induced by ionizing radiation in leukemic cells

Ionizing radiation is a major tool for cancer treatment. The response of eukaryotic cells to ionizing radiation includes apoptosis, a process which requires activation of multiple genes. We sought to determine whether radiation-induced gene expression plays a role in radiation-induced apoptosis. We found Apo2 ligand (Apo2L, also called TRAIL) mRNA induction following gamma-irradiation of Jurkat, MOLT-4, CEM, and PBMC, all human T lineage-derived cells. Increased Apo2L protein levels were found in MOLT-4 and Jurkat cells. Radiation also activated the Apo2L death receptor (DR)5 (also called Apo2, TRAIL-R2, or KILLER) in MOLT-4 cells, which harbor a wild-type p53. We isolated 1152 bp of 5' flanking region of the Apo2L gene and a shorter fragment of 716 bp, both of which showed promoter activity driving the expression of a luciferase reporter gene; however, the response to radiation in MOLT-4 cells was lost when only 430 bp of 5' proximal flanking sequence was maintained. Exogenous Apo2L induced phosphatidylserine exposure on cell membranes, caspase 8 and caspase 3 activation, key markers of apoptosis, confirming that the Apo2L/DR5 pathway is functional in these cells. Bid, a Bcl-2 family protein also known to contribute to receptor-mediated apoptosis, was also activated. To determine whether Apo2L and DR5 were critical for radiation signaling to apoptosis, we stably expressed a dominant negative DR5delta-receptor in Jurkat cells. Cell survival was significantly augmented, indicating that increased Apo2L expression contributed to radiation-induced apoptosis. Clonogenic assays demonstrated that purified, recombinant soluble Apo2L enhanced the lethality of low, therapeutic doses (1-2 Gy) of gamma-irradiation. These data suggest that production of Apo2L may cooperate synergistically with the cytotoxic effect of radiation, and that combinations of Apo2L and radiation may become a powerful tool in clinical therapy.