Safety signal detection with control of latent factors

Postmarket drug safety database like vaccine adverse event reporting system (VAERS) collect thousands of spontaneous reports annually, with each report recording occurrences of any adverse events (AEs) and use of vaccines. We hope to identify signal vaccine-AE pairs, for which certain vaccines are statistically associated with certain adverse events (AE), using such data. Thus, the outcomes of interest are multiple AEs, which are binary outcomes and could be correlated because they might share certain latent factors; and the primary covariates are vaccines. Appropriately accounting for the complex correlation among AEs could improve the sensitivity and specificity of identifying signal vaccine-AE pairs. We propose a two-step approach in which we first estimate the shared latent factors among AEs using a working multivariate logistic regression model, and then use univariate logistic regression model to examine the vaccine-AE associations after controlling for the latent factors. Our simulation studies show that this approach outperforms current approaches in terms of sensitivity and specificity. We apply our approach in analyzing VAERS data and report our findings.

[Epidemiological characteristics and clinical features of pertussis in Shandong Province from 2007 to 2022]

Objective: To analyze the epidemiological characteristics and clinical features of pertussis cases reported in Shandong Province of China. Methods: Data on pertussis cases in Shandong Province from 2007 to 2022 were collected from China Information System for Disease Control and Prevention. At the same time, some case information was collected from the database of notifiable pertussis in Shandong Province from 2007 to 2022. The distribution characteristics and clinical features of pertussis were analyzed. A spatial distribution map of pertussis cases in Shandong Province was drawn. Results: A total of 26 122 pertussis cases were reported in Shandong Province during 2007-2022, with an annual incidence rate ranging from 0.11 to 5.77 cases per 100 000 people. Cases occurred throughout the whole year, with a seasonal peak occurring in spring and summer, especially in July and August. In recent years, reported cases were mainly distributed in the central and western regions of Shandong Province, with fewer cases in the eastern region. The hot spots of the disease shifted from Heze and Dezhou City in 2007-2013 to Jinan and Tai'an city in 2014-2022. The age range of onset was from 1 day to 93 years old. The proportion of cases with age≤1 year was the largest (41.81%, 10 922/26 122), and the proportion of cases aged 0-6 months decreased from 32.21% (67/208)-55.67% (157/282) within the period of 2007 to 2013 to 16.78% (883/5 263)-41.97% (444/1 058) within the period of 2014 to 2022, with a statistically significant trend (χ² trend=670.01, P<0.001). There were 13 682 male cases and 12 440 female cases, with a male-female ratio of 1.10∶1. The male-female ratio was 1.45∶1 (806∶556) from 2007 to 2013 and 1.08∶1 (12 876∶11 884) from 2014 to 2022. The proportion of women increased from 42.31% (88/208) in 2007 to 47.84% (2 518/5 263) in 2022, and with a significant trend (χ² trend=22.25, P<0.001). In pertussis cases, the proportions of scattered children, kindergarten children and students were 71.38% (18 645/26 122), 15.13% (3 951/26 122), and 11.60% (3 031/26 122), respectively. The top five clinical symptoms of pertussis cases were paroxysmal spasmodic cough (86.33%, 21 411 cases), flushing (39.61%, 9 824 cases), restless sleep (34.51%, 8 558 cases), fever (30.80%, 7 638 cases), and crowing (27.53%, 6 829 cases). Among 24 802 cases, there were 15 542 cases (62.66%) with a history of immunization against pertussis vaccine. Conclusion: From 2007 to 2022, the incidence rate of pertussis cases in Shandong Province shows an upward trend, with the majority being young children, and the clinical symptoms are relatively typical.

Blending control method of lower limb exoskeleton toward tripping-free stair climbing

Tripping frequently occurs when an individual climbs the stairs with improper foot clearance. Among older adults, falling down the stairs accounts for over 10% of accidental deaths. This paper proposes an exoskeleton control method that blends human-dominant and exoskeleton-dominant control to prevent tripping. The blending controller not only allows the exoskeleton to track the pilot's movements and provide power assistance during regular walking, but also allows the exoskeleton to help the pilot avoid dangers in some cases. An online path planning method is used to generate a safe trajectory in the exoskeleton-dominant mode to help the pilot correct their running trajectory. The controller provides the pilot with adjustment spaces to adapt to sudden changes in the motion mode and enable active self-regulation. The simulations verified the effectiveness of the proposed blending method. Experiments showed that the robot should be involved in the pilot's movements when the foot clearance exceed the safety threshold to prevent tripping.

Mixture survival trees for cancer risk classification

In oncology studies, it is important to understand and characterize disease heterogeneity among patients so that patients can be classified into different risk groups and one can identify high-risk patients at the right time. This information can then be used to identify a more homogeneous patient population for developing precision medicine. In this paper, we propose a mixture survival tree approach for direct risk classification. We assume that the patients can be classified into a pre-specified number of risk groups, where each group has distinct survival profile. Our proposed tree-based methods are devised to estimate latent group membership using an EM algorithm. The observed data log-likelihood function is used as the splitting criterion in recursive partitioning. The finite sample performance is evaluated by extensive simulation studies and the proposed method is illustrated by a case study in breast cancer.

[Effects of menopause on depressive and anxiety symptoms in community women in Beijing]

Objective: To determine the effects of menopausal stage, age and other associated risk factors on symptoms of anxiety and depression among women in a community in Beijing. Methods: This study was a community-based prospective cohort. Participants who had transitioned through natural menopause, completed two or more depressive and anxiety symptoms evaluations, aged 35 to 64 years, and did not use hormone therapy were selected from the Peking Union Medical College Hospital aging longitudinal cohort of women in midlife to this analysis. The primary outcome variables were depressive and anxiety symptoms, assessed by hospital anxiety and depression scale (HADS). The generalized estimation equation was used in the statistical analysis. Results: Followed up from 2006 to 2014, 430 women and 2 533 HADS assessments were retained in the cohort. Depressive symptoms were more common than anxiety symptoms during all menopausal stages. The incidences of depressive and anxiety symptoms were 14.5% (19/191) and 3.1% (4/191) in the premenopausal -3 stage, respectively. The incidence increased in both menopausal transition and postmenopausal stage, with the highest incidence in the +1c stage [20.6% (155/751) and 8.8% (66/751), respectively]. However, these differences were not statistically significant (all P>0.05). Depressive symptoms were highest in the ≥60-<65 age group [20.8% (74/355)], and anxiety symptoms were highest in the ≥50-<55 age group [8.2% (62/754)]; but there were no statistical significances between different age groups and depressive and anxiety symptoms (all P>0.05). Multivariable analysis showed that high body mass index, low education status, and poor health status were independently associated with depressive symptoms (all P<0.05), and that poor health status, trouble falling asleep, and early awakening were independently associated with anxiety symptoms (all P<0.01). Conclusions: Depressive and anxiety symptoms are more common during menopausal transition and postmenopausal stage compared with reproductive stage. Depressive symptoms are more common than anxiety symptoms. To screen and assess depressive and anxiety symptoms in perimenopausal women is essential, especially for women with high risk factors.

[0ne case report of Chlamydia psittaci pneumonia]

This paper reported a case of severe Chlamydia psittaci pneumonia. The patient had a clear history of contact with sick poultry. The clinical manifestations were dry cough, fever and respiratory failure. Chest CT showed consolidation in the lower lobe of the right lung, and a small amount of exudative ground-glass opacity in the left lung. Chlamydia psittaci was detected in bronchoalveolar lavage fluid (BALF) by metagenomic assay. After treatment with antibiotics such as nitroimidazoles and carbapenems, the patient was discharged with a better health condition.

Efficient Multiple Imputation for Sensitivity Analysis of Recurrent Events Data with Informative Censoring

Missing data are commonly encountered in clinical trials due to dropout or nonadherence to study procedures. In trials in which recurrent events are of interest, the observed count can be an undercount of the events if a patient drops out before the end of the study. In many applications, the data are not necessarily missing at random and it is often not possible to test the missing at random assumption. Consequently, it is critical to conduct sensitivity analysis. We develop a control-based multiple imputation method for recurrent events data, where patients who drop out of the study are assumed to have a similar response profile to those in the control group after dropping out. Specifically, we consider the copy reference approach and the jump to reference approach. We model the recurrent event data using a semiparametric proportional intensity frailty model with the baseline hazard function completely unspecified. We develop nonparametric maximum likelihood estimation and inference procedures. We then impute the missing data based on the large sample distribution of the resulting estimators. The variance estimation is corrected by a bootstrap procedure. Simulation studies demonstrate the proposed method performs well in practical settings. We provide applications to two clinical trials.

[Analysis of Neisseria Meningitidis carriage characteristics among healthy population in Shandong province from 2008 to 2020]

Objective: To analyze the carriage characteristics of Neisseria meningitidis (Nm) among healthy population of epidemic cerebrospinal meningitis in Shandong province. Methods: From April 2008 to April 2020, a total of 16 848 healthy population were recruited from Lixia District of Jinan City, Gaomi City of Weifang City, Jiaxiang County of Jining City, Wendeng District of Weihai City, Tancheng County of Linyi City and Linyi County of Dezhou City for the investigation.Throat swab samples were collected, Nm was isolated, cultured and identified, and Nm carrying characteristics of healthy population with different characteristics were analyzed. Results: Among the 16 848 healthy population, male accounted for 51.86% (8 737). A total of 136 Nm strains were isolated, and the carriage rate was 0.81%. Among the 136 Nm strains, serogroup B (60.29%) and ungroupable strains (23.53%) were dominant. Analysis of the Nm carriage rate, that were higher in the healthy population of Linyi (1.39%) and Jinan (1.14%), higher in 13-16 years old (1.60%) and 17-19 years old (1.10%) healthy population, and higher in male (1.02%). Conclusion: The Nm carriage rate of healthy population is relatively low in Shandong Province, and the proportion of serogroup B and ungroupable Nm is relatively high.

Inferring latent heterogeneity using many feature variables supervised by survival outcome

In cancer studies, it is important to understand disease heterogeneity among patients so that precision medicine can particularly target high-risk patients at the right time. Many feature variables such as demographic variables and biomarkers, combined with a patient's survival outcome, can be used to infer such latent heterogeneity. In this work, we propose a mixture model to model each patient's latent survival pattern, where the mixing probabilities for latent groups are modeled through a multinomial distribution. The Bayesian information criterion is used for selecting the number of latent groups. Furthermore, we incorporate variable selection with the adaptive lasso into inference so that only a few feature variables will be selected to characterize the latent heterogeneity. We show that our adaptive lasso estimator has oracle properties when the number of parameters diverges with the sample size. The finite sample performance is evaluated by the simulation study, and the proposed method is illustrated by two datasets.

[Hospitalized but not admitted and influencing factors for pneumoconiosis patients]

Objective: To investigate the situation where pneumoconiosis patients who should be in hospital are not hospitalized, to analyze the main reasons and influencing factors for their restricted use of hospitalization medical services, and to provide a reference for relevant policy making. Methods: Subjects were sampled in nine provinces, including Zhejiang, Jiangsu, Shandong, and Hebei, using a method that combined stratified sampling and typical sampling, from March 2017 to January 2018. These subjects were patients occupationally diagnosed with pneumoconiosis and patients clinically diagnosed with pneumoconiosis. The questionnaire The health seeking behaviors of pneumoconiosis patients and their influencing factors was used as the survey tool to investigate their health seeking behaviors such as going to the outpatient clinic and being hospitalized. Andersen's Behavioral Model of Health Services Use was used as the analysis model; The χ2 test was used for univariate analysis, and the multivariate logistic regression model was used for multivariate analysis. Results: A total of 1 037 patients with pneumoconiosis were surveyed, with a mean age of 55.9±11.2 years and 67.5% (700/1 037) living in rural areas for a long time. Occupational injury insurance and medical insurance for urban and rural residents were the main insurances used, accounting for 40.9% (424/1 037) and 59.4% (616/1 037) of the cases, respectively. A total of 177 (17.1%) patients were once advised by the doctors to be hospitalized because of pneumoconiosis, while they did not. The proportion of patients who should be in hospital but did not do so among rural patients was significantly higher than that in urban patients (20.1% (141/700) vs 10.7% (36/337) , P<0.05) . Financial difficulties (12.0%, 124/1 037) and self-rated mild symptoms (3.2%, 33/1 037) were the main reasons for not being hospitalized. Model analysis showed that the propensity factor, ability factor, health needs, health seeking behaviors, and self-rated health factor in the Anderson model were all statistically significant (P<0.05) . The main features of high proportion of patients who should be in hospital but did not do so were as follows: personal monthly income below 1 000 RMB (odds ratio[OR]of no income=2.92, 95% confidence interval[CI]: 1.14-7.48; OR of less than 1 000 RMB=3.55, 95%CI: 1.35-9.35) , no occupational injury insurance (OR=2.05, 95%CI: 1.16-3.43) , and concurrent emphysema (OR= 1.98, 95%CI: 1.12-3.50) . Conclusion: Low income, no occupational injury insurance, and concurrent emphy-sema are the main constraining factors for hospitalization services use in pneumoconiosis patients.

[Clinical significance of the N-terminal pro-B-type natriuretic peptide levels in pneumoconiosis patients with chronic pulmonary heart disease]

Objective: To determine the diagnosis value and therapy significance of peripheral blood N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels in pneumoconiosis patients with chronic pulmonary heart disease (CPHD) . Methods: A total of 22 pneumoconiosis complicated with CPHD (A group) , 20 pneumoconiosis complicated with coronary heart disease (B group) and 25 pneumoconiosis without heart disease (C group) were selected. The level of blood NT-proBNP was examined and analyzed in the three groups. We observed the difference blood level of NT-proBNP concentration between before and after of therapy in pneumoconiosis patients with CPHD. The optimal cutoff value of blood NT-proBNP was determined according to the principle of maximum Youden's index associated with clinical analysis. Results: Blood NT-proBNP concentrations were 543.19±78.92, 1017.38±731.06, 109.56±57.46 pg/ml in three groups, respectively. Compared with C group, there was a significant increase in the blood levels of NT-proBNP in both A and B groups (P<0.05, P<0.01) , especially for B group. Compared with NT-proBNP 543.19±78.92 pg/ml before therapy, the153.34±58.40 pg/ml was significantly declined after therapy in B group (P<0.05) . The optional threshold for peripheral blood NT-proBNP level as a diagnostic indicator for pneumoconiosis complicated with CPHD was 450 pg/ml. The specificity and sensitivity of NT-proBNP were 95.46% and 54.17%, respectively. Conclusion: Blood NT-proBNP level may be useful as a tool for monitoring the effect of pneumoconiosis patients with CPHD treatment with higher sensitivity in. Blood NT-proBNP cut-off >450 pg/ml should be applied in clinical practice as a valuable diagnostic prediction for pneumoconiosis patients with CPHD.

Controlling false discovery proportion in identification of drug-related adverse events from multiple system organ classes

Analyzing safety data from clinical trials to detect safety signals worth further examination involves testing multiple hypotheses, one for each observed adverse event (AE) type. There exists certain hierarchical structure for these hypotheses due to the classification of the AEs into system organ classes, and these AEs are also likely correlated. Many approaches have been proposed to identify safety signals under the multiple testing framework and tried to achieve control of false discovery rate (FDR). The FDR control concerns the expectation of the false discovery proportion (FDP). In practice, the control of the actual random variable FDP could be more relevant and has recently drawn much attention. In this paper, we proposed a two-stage procedure for safety signal detection with direct control of FDP, through a permutation-based approach for screening groups of AEs and a permutation-based approach of constructing simultaneous upper bounds for false discovery proportion. Our simulation studies showed that this new approach has controlled FDP. We demonstrate our approach using data sets derived from a drug clinical trial.

Efficient methods for signal detection from correlated adverse events in clinical trials

It is an important and yet challenging task to identify true signals from many adverse events that may be reported during the course of a clinical trial. One unique feature of drug safety data from clinical trials, unlike data from post-marketing spontaneous reporting, is that many types of adverse events are reported by only very few patients leading to rare events. Due to the limited study size, the p-values of testing whether the rate is higher in the treatment group across all types of adverse events are in general not uniformly distributed under the null hypothesis that there is no difference between the treatment group and the placebo group. A consequence is that typically fewer than 100 α percent of the hypotheses are rejected under the null at the nominal significance level of α . The other challenge is multiplicity control. Adverse events from the same body system may be correlated. There may also be correlations between adverse events from different body systems. To tackle these challenging issues, we develop Monte-Carlo-based methods for the signal identification from patient-reported adverse events in clinical trials. The proposed methodologies account for the rare events and arbitrary correlation structures among adverse events within and/or between body systems. Extensive simulation studies demonstrate that the proposed method can accurately control the family-wise error rate and is more powerful than existing methods under many practical situations. Application to two real examples is provided.

[Influence of Saccharomyces boulardii Sachets combined with bismuth quadruple therapy for initial Helicobacter pylori eradication]

Objective: To evaluate the efficacy and safety of Saccharomyces boulardii Sachets combined with bismuth quadruple therapy for initial Helicobacter pylori(H.pylori) eradication. Methods: From March 2014 to March 2015, 240 participants from the third hospital of Hebei medical university with H. pylori infection were recruited and randomized into three groups: Quadruple therapy group received bismuth potassium citrate 220 mg bid + Rabeprazole 10 mg bid + amoxicillin 1 000 mg bid+ furazolidone 100 mg bid for 10 days. Short-term group and long-term group received the same quadruple therapy for 10 days as above, as well as Saccharomyces boulardii Sachets 500 mg bid for 14 days and 28 days, respectively. H. pylori eradication was confirmed by (13)C/(14)C-UBT at least 4 weeks after completion of therapy. And side effects were investigated during the therapy. Results: The H. pylori eradication rates in quadruple therapy, short-term and long-term group were 80%, 87.5% and 87.5% by ITT analysis (P=0.321) and 92.8%, 94.6% and 95.9% by PP analysis (P=0.717), respectively. The overall side effect rate and occurrence of diarrhea and abdominal distension were significantly lower in short-term or long-term group as compared with quadruple therapy group(P=0.007, 0.003, 0.004), but there was no significant difference between the two probiotics groups. Conclusions: Both short and long-term Saccharomyces boulardii Sachets reduced the overall side effect rate and occurrence of diarrhea or abdominal distension when combined with bismuth quadruple therapy for initial H. pylori eradication and no difference was observed in efficacy or safety between the two groups.

[Etiologic surveillance and analysis of acute meningitis and encephalitis syndrome in Jinan city in 2013-2016]

Objective: To characterize the etiology and epidemiological characteristics of the acute meningitis and encephalitis syndrome (AMES) in Jinan city in 2013-2016. Methods: The epidemiological data, clinical diagnosis, serum and cerebrospinal fluid (CSF) specimens were collected from 3 577 AMES cases in 6 sentinel hospitals in Jinan city in 2013-2016. Samples of all cases were made sero-diagnosis for Immunoglobulin (Ig) M antibody to Japanese encephalitis virus (JEV) and negative cases of JEV for enterovirus (EV), mumps virus (MuV) and herpes simplex virus (HSV) by enzyme-linked immunosorbent assay (ELISA). Virus isolation and molecular identification were performed. Positive rates were analyzed by Chi-square test. Results: In 2013-2016, the positive rates of JEV, EV, MuV and HSV were 9.0% (322/3 577 cases), 22.1% (643/2 916 cases), 9.9% (289/2 916 cases), 26.9% (783/2 916), respectively. Of these, the positive rates of JEV were 32.9% (261/794), 1.2% (14/1 175), 1.0% (8/807) and 4.9% (39/801 cases); EV: 19.5% (91/466), 35.1% (342/974 cases), 15.5% (115/743) and 13.0% (95/733); MuV: 9.2% (43/466), 14.4% (140/974), 9.0% (67/743) and 5.3% (39/733). HSV: 35.4% (165/466), 38.5% (375/974), 25.7% (191/743) and 7.1% (52/733). There were significant differences in positive rates of 4 kinds of viruses in 2013-2016 (P<0.001). A total of 81 EV strains belonging to 8 serotypes were isolated from 1 020 CSF specimens. The positive rates were 4.8% (6 cases), 13.1% (55 cases), 4.1% (7 cases) and 4.2% (13 cases) from 2013 to 2016. Coxsackievirus (CV) B5, echovirus (E) 6 and E30 accounted for 46% (37 isolates), 22% (18 isolates) and 21% (17 isolates) of all strains. Conclusion: The AMES cases in Jinan city in 2013-2016 were mainly caused by HSV, EV, MuV, JEV. CVB5, E6 and E30 were the dominant serotypes of EV associated with AMES cases in Jinan city.

[Analysis of current epidemiological and clinical characteristics for laboratory confirmed epidemic cerebrospinal meningitis cases in Shandong Province, 2007-2016]

Objective: To analyze epidemiological and clinical characteristics of laboratory confirmed epidemic cerebrospinal meningitis cases. Methods: Epidemiological and clinical informations and cerebrospinal fluid (CSF) and blood specimens of AMES (acute meningitis/encephalitis syndrome) cases were collected in the six sentinel hospitals from 2007 to 2016. neisseria meningitides (Nm) species and serogroup identification were detected by the methods of real-time fluorescent quantitative polymerase chain reaction (Real-time PCR) and bacterial culture, and epidemiological and clinical characteristics of laboratory confirmed epidemic cerebrospinal meningitis cases were analyzed. Results: 6 809 AMES cases were reported from 2007 to 2016. Total 4 422 cases were detected, and 90 cases were Nm positive. Through the methods of Real-time PCR, bacterial blood culture and CSF culture, the numbers of Nm positive cases were 90, 2 and 1 respectively. Twenty-two Nm cases were identified from 2007 to 2011 (4 cases were ungrouped), which with the highest incidence in serogroup C cases (17/18), and one cases was ungroupable Nm. Nm laboratory confirmed cases (68 cases) were increased dramatically and mainly occurred in serogroup B cases (43/67, 64.2%) from 2012 to 2016, with serogroup C cases highly decreased (5/67, 7.5%) and ungroupable Nm cases increased (13/67, 19.4%) meanwhile. Serogroup W135 and X cases were first detected at 2012 and 2014, and serogroup A remaining a low level which only detected one case at 2013. The morbidity of epidemic cerebrospinal meningitis was occured in the whole year, and mainly in winter and spring. The ratio of Nm laboratory confirmed cases to AMES cases during November to May (3.5%, 67/1 920) was higher than that during June to October (0.9%, 23/2 502) (χ(2)=34.45, P<0.001). Most Nm cases were children, students and farmers, and account for 30.0% (27/90), 31.1% (28/90), 18.9% (17/90), respectively. The majority of Nm cases were under 20 years old (60/90, 66.67%), and serogroup C cases (17/22, 77.3%) mainly occurred in over 12 years old population, while serogroup B (24/43, 55.8%) and ungroupable (6/14) cases mainly occurred in under 12 years old population. The main clinical symptoms of epidemic cerebrospinal meningitis cases were fever (78/90, 86.7%), headache (59/90, 65.6%) and vomiting (51/90, 56.7%). Misdiagnosis rate of admitting diagnosis was up to 87.8% (79/90) for the reason of atypical features in specific symptoms and blood or CSF positive index. The well-healed ratio in correct diagnosed group (7/11) was higher than that in misdiagnosed group (2.5%, 2/79) (χ(2)=40.61, P<0.001). Conclusion: The clinical symptoms of epidemic cerebrospinal meningitis cases were atypical, and the diagnosed sensitivity and accuracy would be improved by enhanced molecular biology detection. The predominant epidemic serogroup of Nm switched from serogroup C to B, and the key work was surveaylance of serogroup transition.

Outbreak of mass mortality of yearling groupers of Epinephelus (Perciformes, Serranidae) associated with the infection of a suspected new enteric Sphaerospora (Myxozoa: Myxosporea) species in South China Sea

A suspected new enteric Sphaerospora species was believed to be directly associated with the mass mortality of yearling groupers of Epinephelus spp. in South China. The epizootic generally emerged from late September to late April of the following year. The infection prevalence and mortality rate were significantly negatively correlated with fish size. Clinical signs included anorexia, cachexia and extrusion of white pulp-like substance from anus after gentle pressure on the abdomen. Upon necropsy, severe intestinal oedema, thin and transparent intestinal wall, swollen spleen, kidney and gall bladder could be observed. Wet preparation of the infected samples showed large amount of typical disporous plasmodia of the genus Sphaerospora, but no mature spores were observed. Epidemiological investigation showed that this parasite exclusively infected Epinephelus groupers. Histopathologically, this species mainly infected the epithelium of intestine and kidney tubules and caused severe epithelia sloughing and the collapse of intestinal villus. Interestingly, this enteric myxosporidiosis did not cause severe emaciation of infected fish for mass mortality usually emerged within 2-3 days after appearance of clinical signs. The species was most genetically related to Sphaerospora fugu (89% sequence identity) and phylogenetically positioned within marine Sphaerospora lineage. This is the first report of enteric sphaerosporosis of groupers.

[Effect of snow sports on knee cartilage maturation in children and adolescent with MRI quantitative analysis Zhang]

Objective: To evaluate the effect of snow sports to the knee cartilage maturation of children and adolescent with quantitative analysis of 3.0 T MRI. Methods: Twenty children and adolescent who underwent snow sports training more than 6 months (11 males and 9 females) were recruited and named with sports group, and twenty children and adolescent who live regularly without any exercise (10 males and 10 females) were recruited as control group from June 2014 to June 2015.Each group was divided into subgroups according to their gender.Both groups were scanned by 3.0 T MR.According to the loading features of knee articular cartilage in snow sports, medial femoral condyle, lateral femoral condyle, medial tibial condyle and lateral tibial condyle were divided into subareas.T₂ values and cartilage thickness were measured in all areas. Results: The median ages of the sports group and control group were 14.2 and 13.6 years old, which showed no statistical difference between two groups.The BMI of the sports group and control group were 18.3 and 17.9 kg/m^2, which showed no statistical difference between two groups.Both in sports group and control group, the thickness and T₂ values of all areas showed significant differences between man and women in each group (all P<0.05). The cartilage thickness of sports group was higher than control group (P<0.05). The T₂ values showed no statistical difference in anterior central, posterior central of femoral condyles and anterior, central areas of tibial condyles between sports group and control group(P≥0.05). The T₂ values of anterior part of posterior femur and posterior areas of tibial condyle in sports group was higher than control group (P≥0.05). Conclusion: Gender difference may be an important effect factor of cartilage thickness. Scientific snow sports training maybe has positive influence for cartilage maturation of children and adolescent.

Influence of arginine on the growth, arginine metabolism and amino acid consumption profiles of Streptococcus thermophilus T1C2 in controlled pH batch fermentations

AIMS

The aim of this study was to elucidate the effect of arginine on the growth, arginine metabolism and amino acid consumption profiles of Streptococcus thermophilus T1C2.

METHODS AND RESULTS

The growth kinetics, intracellular pH, extracellular osmotic pressure, expression of key genes in the arginine metabolism pathway and amino acid consumption profiles were analysed in chemically defined medium with different initial arginine concentrations. The results showed that arginine stimulated the growth of Strep. thermophilus T1C2 under low intracellular pH and high extracellular osmotic pressure. The expression of key genes in the arginine degradation pathway indicated that arginine relieved the drop in the intracellular pH by consuming protons and generating NH3 . Additionally, the results showed that arginine degradation did not occur via the arginine deiminase pathway but through the arginine decarboxylase-urease pathway. Furthermore, the utilization efficiency of amino acids was improved in the presence of arginine.

CONCLUSIONS

Arginine improved the growth of Strep. thermophilus due to protecting Strep. thermophilus against intracellular acid stress, which was revealed at the transcriptional level of key genes. This study showed that the acid resistance of Strep. thermophilus was achieved through the arginine decarboxylase-urease pathway.

SIGNIFICANCE AND IMPACT OF THE STUDY

The arginine-stimulated growth of Strep. thermophilus improved the utilization efficiency of amino acids and reduced nitrogen waste, which could be useful for the optimization of cultivation media.

[Association analysis between urbanization and non-communicable diseases and health-related behavior]

OBJECTIVE

To explore the association between different urbanization levels and non-communicable diseases (NCDs) in China and provide suggestions on designing relevant health policies in the urbanization process.

METHODS

We obtained health-related data from China Health and Retirement Longitudinal Study (CHARLS) 2011. This study used multistage sampling in design stage and covered 150 districts/counties, representative at the levels of the country. Geo-information system (GIS) method was used to get district areas data, and in combination with the Sixth National Census population data, we computed the population density which was regarded as the proxy variable of urbanization level in every city. The Logistic model was used to explore the effect of urbanization level on hypertension, diabetes, smoking, drinking, overweight and obesity.

RESULTS

Compared with other cities in China, Shanghai and Shenzhen, with the population density of more than 3 000 people per km(2), were the cities with highest urbanization level. From the map of urbanization distribution across China, it was found that the urbanization levels of the northwestern districts were lower than those of the southeastern and coastal districts. The hypertension rate increased with the development of urbanization but there was no statistical significance. The proportion of patients with diabetes went up first and then saw a decrease trend in the process of urbanization. Drinking rate, overweight rate and obesity rate had similar trends, falling to their lowest point when urbanization level equaled 737,1 186 and 1 353 people per km(2) respectively and then experienced upward trends. By contrast, smoking rate declined first and then went up (the turning point was 1 029 people per km(2)).

CONCLUSION

Different urbanization levels have different effects on NCDs, health-related behavior, overweight and obesity. Low urbanization level may create negative impact on health while high level can pose positive effect and increase people's health condition possibly due to the improvement of health care accessibility and the quality of living environment. Policy-makers should specially focus on different residents'health problems in different periods of urbanization, such as the impact of environmental pollution, health resources' allocation and accessibility of health services. It is necessary to reduce or avoid the negative effect of urbanization on NCDs during the local development process to face the NCDs' threat.

[Effect of air pollution on health service demand of the elderly and middle-age patients with hypertension, cardiovascular and cerebrovascular diseases: based on analysis of data from CHARLS]

OBJECTIVE

To study the association of air pollution with health service demand of the elderly and middle-age patients with cardiovascular and cerebrovascular diseases, and to provide a scientific basis for development of environmental protection policy and health service policy of the Chinese government.

METHODS

This study included survey data on self-evaluated health, outpatient service demand and inpatient service demand of the patients with hypertension, heart disease and stroke in 62 cities of 17 provinces from China Health and Retirement Longitudinal Study (CHARLS) in 2011 and 2013, and combined it with the data on the annual concentrations of inhalable particulate matter (PM(10)), sulfur dioxide(SO(2)) and nitrogen dioxide (NO(2)) of those provinces and cities. Conditional Logistic regression was carried out to assess the possible effects of air pollutants on self-evaluated health and health service utilization.

RESULTS

The results showed that turning points existed in the effects of concentrations of NO(2) and SO(2) on the health service demand of the patients with hypertension, heart disease and stroke. The inpatient service demand of the hypertension patients increased with NO(2) concentration when it was lower than 35.1 μg/m(3) and decreased with NO(2) concentration for higher value. Self-evaluated health of the patients with heart disease and stroke decreased with SO(2) concentration when it was lower than 63.8 μg/m(3) and increased with SO(2) concentration for higher value. In addition, no evidence was found for the association between PM(10) and health service demand.

CONCLUSION

Air pollution may have effects on health service demand of the patients with hypertension,cardiovascular and cerebrovascular diseases, and different air pollutants at high or low concentration may have different health effects.

Substitution of Wheat for Corn in Beef Cattle Diets: Digestibility, Digestive Enzyme Activities, Serum Metabolite Contents and Ruminal Fermentation

The objective of this study was to evaluate the effect of diets containing different amounts of wheat, as a partial or whole substitute for corn, on digestibility, digestive enzyme activities, serum metabolite contents and ruminal fermentation in beef cattle. Four Limousin×LuXi crossbred cattle with a body weight (400±10 kg), fitted with permanent ruminal, proximal duodenal and terminal ileal cannulas, were used in a 4×4 Latin square design with four treatments: Control (100% corn), 33% wheat (33% substitution for corn), 67% wheat (67% substitution for corn), and 100% wheat (100% substitution for corn) on a dry matter basis. The results showed that replacing corn with increasing amounts of wheat increased the apparent digestibility values of dry matter, organic matter, and crude protein (p<0.05). While the apparent digestibility of acid detergent fiber and neutral detergent fiber were lower with increasing amounts of wheat. Digestive enzyme activities of lipase, protease and amylase in the duodenum were higher with increasing wheat amounts (p<0.05), and showed similar results to those for the enzymes in the ileum except for amylase. Increased substitution of wheat for corn increased the serum alanine aminotransferase concentration (p<0.05). Ruminal pH was not different between those given only corn and those given 33% wheat. Increasing the substitution of wheat for corn increased the molar proportion of acetate and tended to increase the acetate-to-propionate ratio. Cattle fed 100% wheat tended to have the lowest ruminal NH₃-N concentration compared with control (p<0.05), whereas no differences were observed among the cattle fed 33% and 67% wheat. These findings indicate that wheat can be effectively used to replace corn in moderate amounts to meet the energy and fiber requirements of beef cattle.

Effects of Three Feeding Systems on Production Performance, Rumen Fermentation and Rumen Digesta Particle Structure of Beef Cattle

The effects of three different feeding systems on beef cattle production performance, rumen fermentation, and rumen digesta particle structure were investigated by using 18 Limousin (steers) with a similar body weight (575±10 kg) in a 80-d experiment. The animals were equally and randomly divided into three treatment groups, namely, total mixed ration group (cattle fed TMR), SI1 group (cattle fed concentrate firstly then roughage), and SI2 group (cattle fed roughage firstly then concentrate). The results showed that the average daily gain was significantly higher in cattle receiving TMR than in those receiving SI1 and SI2 (p<0.05). Consumption per kg weight gain of concentrate, silage, and combined net energy (NEmf) were significantly decreased when cattle received TMR, unlike when they received SI1 and SI2 (p<0.05), indicating that the feed efficiency of TMR was the highest. Blood urea nitrogen (BUN) was significantly decreased when cattle received TMR compared with that in cattle receiving SI1 (p<0.05), whereas there was no difference compared with that in cattle receiving SI2. Ammonia nitrogen concentration was significantly lower in cattle receiving TMR than in those receiving SI1 and SI2 (p<0.05). The rumen area of cattle that received TMR was significantly larger than that of cattle receiving SI1 (p<0.05), but there was no difference compared with that of cattle receiving SI2. Although there was no significant difference among the three feeding systems in rumen digesta particle distribution, the TMR group trended to have fewer large- and medium-sized particles and more small-sized particles than those in the SI1 and SI2 groups. In conclusion, cattle with dietary TMR showed increased weight gain and ruminal development and decreased BUN. This indicated that TMR feeding was more conducive toward improving the production performance and rumen fermentation of beef cattle.

A miniature surface tension-driven robot using spatially elliptical moving legs to mimic a water strider's locomotion

The highly agile and efficient water-surface locomotion of the water strider has stimulated substantial interest in biomimetic research. In this paper, we propose a new miniature surface tension-driven robot inspired by the water strider. A key feature of this robot is that its actuating leg possesses an ellipse-like spatial trajectory similar to that of a water strider by using a cam-link mechanism. Simplified models are presented to discuss the leg-water interactions as well as critical conditions for a leg penetrating the water surface, and simulations are performed on the robot's dynamic properties. The final fabricated robot weighs about 3.9 g, and can freely and stably walk on water at different gaits. The maximum forward and turning speeds of the robot are measured as 16 cm s(-1) and 23°/s, respectively. Furthermore, a similarity analysis with Bond number and Weber number demonstrates that the locomotion of this robot is quite analogous to that of a real water strider: the surface tension force dominates the lifting force and plays a major role in the propulsion force. This miniature surface tension-driven robot might have potential applications in many areas such as water quality monitoring and aquatic search and rescue.

Characterization of a novel anther-specific gene encoding a leucine-rich repeat protein in petunia

In Petunia x hybrida 'Fantasy Red', a leucine-rich repeat (LRR) gene referred to as PhLRR, was identified in a flower bud cDNA library. The open reading frame sequence of PhLRR was 1251 bp, encoding a putative 46.2-kDa protein of 416 amino acids. The PhLRR protein showed high similarity to members of polygalacturonase inhibitor proteins (PGIPs), contained 11 conserved LRR domains, and was an extracellular localization protein. Phylogenetic analysis showed that PhLRR belonged to the same PGIPs subfamily as SHY, indicating that PhLRR may be involved in the development of pollen-like SHY. Expression analysis revealed that PhLRR was abundantly expressed during early stages of flower bud and anther development, while it was not detected in any other examined organs, such as sepals, petals, pistils, roots, stems, leaves, or open flowers. Furthermore, many cis-acting elements (such as AGAAA and GTGA) related to anther-specific gene expression were identified in the PhLRR gene promoter region, indicating that the promoter is also anther-specific. These results suggested that PhLRR is a novel anther-specific gene that may be essential for the early development of anthers.

Bayesian probability of success for clinical trials using historical data

Developing sophisticated statistical methods for go/no-go decisions is crucial for clinical trials, as planning phase III or phase IV trials is costly and time consuming. In this paper, we develop a novel Bayesian methodology for determining the probability of success of a treatment regimen on the basis of the current data of a given trial. We introduce a new criterion for calculating the probability of success that allows for inclusion of covariates as well as allowing for historical data based on the treatment regimen, and patient characteristics. A new class of prior distributions and covariate distributions is developed to achieve this goal. The methodology is quite general and can be used with univariate or multivariate continuous or discrete data, and it generalizes Chuang-Stein's work. This methodology will be invaluable for informing the scientist on the likelihood of success of the compound, while including the information of covariates for patient characteristics in the trial population for planning future pre-market or post-market trials.

A note on effective sample size for constructing confidence intervals for the difference of two proportions

Proportion differences are often used to estimate and test treatment effects in clinical trials with binary outcomes. In order to adjust for other covariates or intra-subject correlation among repeated measures, logistic regression or longitudinal data analysis models such as generalized estimating equation or generalized linear mixed models may be used for the analyses. However, these analysis models are often based on the logit link which results in parameter estimates and comparisons in the log-odds ratio scale rather than in the proportion difference scale. A two-step method is proposed in the literature to approximate the calculation of confidence intervals for the proportion difference using a concept of effective sample sizes. However, the performance of this two-step method has not been investigated in their paper. On this note, we examine the properties of the two-step method and propose an adjustment to the effective sample size formula based on Bayesian information theory. Simulations are conducted to evaluate the performance and to show that the modified effective sample size improves the coverage property of the confidence intervals.

Handling missing data in vaccine clinical trials for immunogenicity and safety evaluation

In clinical trials, study subjects are usually followed for a period of time after treatment, and the missing data issue is almost inevitable due to various reasons, including early dropout or lost-to-follow-up. It is important to take the missing data into consideration at the study design stage to minimize its occurrence throughout the study and to prospectively account for it in the analyses. There are many methods available in the literature that are designed to handle the missing data issue under various settings. Vaccines are biological products that are primarily designed to prevent infectious diseases, and are different from pharmaceutical products, which traditionally have been chemical products designed to treat or cure diseases. While a lot of similarities exist between clinical trials for vaccines and those for pharmaceutical products, there are some unique issues in vaccine trials, including how to handle the missing data, which calls for special considerations. In this report we present a variety of statistical approaches for analyses of vaccine immunogenicity and safety trials in the presence of missing data. The methods are illustrated with numerical simulations and vaccine trial examples.

Assessing non-inferiority to an aggregate response with an application to development of pneumococcal conjugate vaccines

The development of a new pneumococcal conjugate vaccine involves assessing the responses of the new serotypes included in the vaccine. The World Health Organization guidance states that the response from each new serotype in the new vaccine should be compared with the aggregate response from the existing vaccine to evaluate non-inferiority. However, no details are provided on how to define and estimate the aggregate response and what methods to use for non-inferiority comparisons. We investigate several methods to estimate the aggregate response based on binary data including simple average, model-based, and lowest response methods. The response of each new serotype is then compared with the estimated aggregate response for non-inferiority. The non-inferiority test p-value and confidence interval are obtained from Miettinen and Nurminen's method, using an effective sample size. The methods are evaluated using simulations and demonstrated with a real clinical trial example.

Sensitive and rapid detection of Vibrio corallilyticus by loop-mediated isothermal amplification targeted to the alpha subunit gene of RNA polymerase

AIMS

A diagnostic protocol was developed for rapid detection of Vibrio corallilyticus by method of loop-mediated isothermal amplification (LAMP).

METHODS AND RESULTS

For cloning and sequencing of rpo A gene of V. corallilyticus, a set of four LAMP primers were designed by targeting the rpoA gene. With Bst DNA polymerase, the reaction time and temperature were optimized for 70 min at 65 degrees C, respectively. The amplification products were detected by electrophoresis. The detection limit of V. corallilyticus by LAMP was 3.6 x 10(3) CFU ml(-1) (8 CFU per reaction), but PCR could detect up to 3.6 x 10(4) CFU ml(-1) (72 CFU per reaction). The LAMP method was ninefold more sensitive than conventional PCR. The results also indicated that the LAMP reaction was highly specific to V. corallilyticus.

CONCLUSIONS

The LAMP assay was a sensitive, specific and cost-effective method for the rapid detection of V. corallilyticus.

SIGNIFICANCE AND IMPACT OF THE STUDY

This LAMP method provides an important diagnostic tool for the detection of V. corallilyticus infection. It can replace laborious biochemical tests for the identification of V. corallilyticus.

Should baseline be a covariate or dependent variable in analyses of change from baseline in clinical trials?

In randomized clinical trials, a pre-treatment measurement is often taken at baseline, and post-treatment effects are measured at several time points post-baseline, say t=1, ..., T. At the end of the trial, it is of interest to assess the treatment effect based on the mean change from baseline at the last time point T. We consider statistical methods for (i) a point estimate and 95 per cent confidence interval for the mean change from baseline at time T for each treatment group, and (ii) a p-value and 95 per cent confidence interval for the between-group difference in the mean change from baseline. The manner in which the baseline responses are used in the analysis influences both the accuracy and the efficiency of items (i) and (ii). In this paper, we will consider the ANCOVA approach with change from baseline as a dependent variable and compare that with a constrained longitudinal data analysis (cLDA) model proposed by Liang and Zeger (Sankhya: Indian J. Stat. (Ser B) 2000; 62:134-148), in which the baseline is modeled as a dependent variable in conjunction with the constraint of a common baseline mean across the treatment groups. Some drawbacks of the ANCOVA model and potential advantages of the cLDA approach are discussed and illustrated using numerical simulations.

Bivariate genetic modelling of the response to an oral glucose tolerance challenge: a gene x environment interaction approach

AIMS/HYPOTHESIS

Twin and family studies have shown the importance of genetic factors influencing fasting and 2 h glucose and insulin levels. However, the genetics of the physiological response to a glucose load has not been thoroughly investigated.

METHODS

We studied 580 monozygotic and 1,937 dizygotic British female twins from the Twins UK Registry. The effects of genetic and environmental factors on fasting and 2 h glucose and insulin levels were estimated using univariate genetic modelling. Bivariate model fitting was used to investigate the glucose and insulin responses to a glucose load, i.e. an OGTT.

RESULTS

The genetic effect on fasting and 2 h glucose and insulin levels ranged between 40% and 56% after adjustment for age and BMI. Exposure to a glucose load resulted in the emergence of novel genetic effects on 2 h glucose independent of the fasting level, accounting for about 55% of its heritability. For 2 h insulin, the effect of the same genes that already influenced fasting insulin was amplified by about 30%.

CONCLUSIONS/INTERPRETATION

Exposure to a glucose challenge uncovers new genetic variance for glucose and amplifies the effects of genes that already influence the fasting insulin level. Finding the genes acting on 2 h glucose independently of fasting glucose may offer new aetiological insight into the risk of cardiovascular events and death from all causes.

Ion beam induced formation and interrogation of Au nanoclusters

Low-energy ion bombardment of a Au thin film by 0.5 keV Ar+ forms self-organized nanoclusters that display quantum size effects. The reduction of Au coverage with sputtering time is quantified with x-ray photoemission spectroscopy, and a decrease of both the rms roughness and correlation length is measured by STM. Neutralization of scattered 3 keV Na+ and K+ alkali-metal ions is used to probe the electronic states of the sputter-induced nanoclusters. The neutral fractions gradually increase as the cluster dimensions decrease, indicating that the electronic structure is similar to that of clusters grown by deposition.

Stable Agrobacterium-mediated genetic transformation of London plane tree (Platanus acerifolia Willd.)

London plane tree (Platanus acerifolia Willd.) is an important tree in urban landscaping but it suffers from a number of negative traits which genetic engineering could be used to address. As with many woody species, P. acerifolia has appeared recalcitrant to genetic transformation. However, the recent development of a method for regenerating shoots from P. acerifolia leaf explants suggests that such material could be a target for gene-transfer. Using an Agrobacterium tumefaciens strain in which the T-DNA carries the histochemically detected reporter gene beta-glucuronidase (GUS), we have followed the transfer of genes from Agrobacterium to leaf explants of Platanus acerifolia. Using this system, we have identified a set of inoculation and co-cultivation conditions (notably: the pre-treatment of leaf explants with 0.4 M mannitol, an inoculation period of 10 min, a bacterial OD(600) of 0.8-1.0 and a co-cultivation period of 5 days) that permit a good frequency and reliability of transient gene-transfer. Optimum levels of antibiotics for bacterial elimination and kanamycin-resistant shoot regeneration were also established. By applying these parameters, we recovered eight independent stably transformed shoots that were kanamycin-resistant and contained the nptII T-DNA gene, as confirmed by PCR analysis. Furthermore, Southern blot analysis confirmed that, in at least five of these lines, the transgene was associated with high molecular weight DNA, so indicating integration into the plant genome.

Stable Agrobacterium-mediated genetic transformation of London plane tree (Platanus acerifolia Willd.)

London plane tree (Platanus acerifolia Willd.) is an important tree in urban landscaping but it suffers from a number of negative traits which genetic engineering could be used to address. As with many woody species, P. acerifolia has appeared recalcitrant to genetic transformation. However, the recent development of a method for regenerating shoots from P. acerifolia leaf explants suggests that such material could be a target for gene-transfer. Using an Agrobacterium tumefaciens strain in which the T-DNA carries the histochemically detected reporter gene beta-glucuronidase (GUS), we have followed the transfer of genes from Agrobacterium to leaf explants of Platanus acerifolia. Using this system, we have identified a set of inoculation and co-cultivation conditions (notably: the pre-treatment of leaf explants with 0.4 M mannitol, an inoculation period of 10 min, a bacterial OD(600) of 0.8-1.0 and a co-cultivation period of 5 days) that permit a good frequency and reliability of transient gene-transfer. Optimum levels of antibiotics for bacterial elimination and kanamycin-resistant shoot regeneration were also established. By applying these parameters, we recovered eight independent stably transformed shoots that were kanamycin-resistant and contained the nptII T-DNA gene, as confirmed by PCR analysis. Furthermore, Southern blot analysis confirmed that, in at least five of these lines, the transgene was associated with high molecular weight DNA, so indicating integration into the plant genome.

Li ion scattering from Au nanoclusters on TiO2(110)

The neutralization of low energy 7Li+ scattered from Au nanoclusters deposited on TiO2(110) was measured with time-of-flight spectroscopy as a function of cluster size, emission angle, and ion energy. The neutralization shows maxima for cluster diameters approximately 3 nm, and again for thick Au films. The data are compared to previous experiments with Na projectiles. Possible explanations of the observed effects are discussed.

Detection of quantum confined states in au nanoclusters by alkali ion scattering

Charge state-resolved time-of-flight spectra were collected for 2.0 keV 23Na+ scattered from Au nanoclusters deposited on TiO2(110). The neutral fraction of Na scattered from metallic Au is low ( approximately 3%), but it is surprisingly high (up to 50%) for small clusters. The results demonstrate that alkali ions couple to electronic states specific to the nanoclusters, and that the energy of the states is a function of the nanocluster size. This technique provides a new method for the spectroscopy of nanomaterials.

QTL x environment interactions in rice. I. heading date and plant height

One hundred twenty six doubled-haploid (DH) rice lines were evaluated in nine diverse Asian environments to reveal the genetic basis of genotype x environment interactions (GEI) for plant height (PH) and heading date (HD). A subset of lines was also evaluated in four water-limited environments, where the environmental basis of G x E could be more precisely defined. Responses to the environments were resolved into individual QTL x environment interactions using replicated phenotyping and the mixed linear-model approach. A total of 37 main-effect QTLs and 29 epistatic QTLs were identified. On average, these QTLs were detectable in 56% of the environments. When detected in multiple environments, the main effects of most QTLs were consistent in direction but varied considerably in magnitude across environments. Some QTLs had opposite effects in different environments, particularly in water-limited environments, indicating that they responded to the environments differently. Inconsistent QTL detection across environments was due primarily to non- or weak-expression of the QTL, and in part to significant QTL x environment interaction effects in the opposite direction to QTL main effects, and to pronounced epistasis. QTL x environment interactions were trait- and gene-specific. The greater GEI for HD than for PH in rice were reflected by more environment-specific QTLs, greater frequency and magnitude of QTL x environment interaction effects, and more pronounced epistasis for HD than for PH. Our results demonstrated that QTL x environment interaction is an important property of many QTLs, even for highly heritable traits such as height and maturity. Information about QTL x environment interaction is essential if marker-assisted selection is to be applied to the manipulation of quantitative traits.

[Distribution of 131I-cytotoxin 14 from Naja naja atra venom in rats]

Cytotoxin 14 (CT14) from Naja naja atra venom was labelled with 131I by chloramine-T method and its tissue distribution was studied in rats. The highest concentration of the cytotoxin was found in kidney, 5979 dpm per mg weight, 14 times more than that of the control animals, at 0.5 h after i.v. injection and high concentrations were found in liver, spleen, pancreas, and adrenal. CT14 was also found in brain at 2 h after injection, 50 dpm per mg weight, 3 times more than that of the control.

A health survey of workers in the pentachlorophenol section of a chemical manufacturing plant

During 1968 to 1985, 109 workers who had been engaged in the production of pentachlorophenol, using non-gamma isomers of hexachloroclohexane (BHC) as the raw material, were surveyed. Endemic chloracne among them had been noted since 1974. The prevalence of chloracne was 73.4% (80/109) in total and 95.2% (20/21) in a trichlorobenzene (TCB) tank area where dioxin and dibenzofurans levels were thousands of ppm. To our knowledge, PCDDs and PCDFs have not previously been reported from thermal decomposition of BHC. Urinary porphyrins were significantly higher among exposed workers than among the controls but there was no significant difference between the workers with chloracne and those without. The conduction velocities of the median motor nerves were much slower among the workers in the TCB tank area where the highest PCDDs contamination appeared. The mortality study cohort was relatively young. Based on the three deaths observed during the follow-up, no association could be drawn.

[Purification and anticancer activity of cytotoxin-14 from venom of Naja naja atra]

Ion-chromatography of lyophilized cobra (Naja naja atra) venom on SP-Sephadex C-50 yielded 14 fractions, of which 7, 8, 9, and 10 possessed neurotoxic actions and 11, 12, 13, and 14 had cytotoxic activities. Chromatography of fraction 14 on SP-Sephadex C-25 gave cytotoxin-14. It was homogeneous on polyacrylamide gel electrophoresis with m = 7448 Da. It was a typical cytotoxin without phospholipase A2 activity and had a selective cytotoxic action on human cancer cell lines.

Effects of an acidic phospholipase A2 purified from Ophiophagus hannah (king cobra) venom on rat heart

An acidic phospholipase A2 (OHV A-PLA2) purified from Ophiophagus hannah venom had a cardiotoxic action on rat heart. In rats OHV A-PLA2 (2-4 mg/kg) caused ECG abnormalities including decreased heart rate, prolonged P-R interval, widened QRS complex and complete A-V block. When tested on isolated rat right atria, OHV A-PLA2 (10-20 micrograms/ml) produced a positive chronotropic effect. When tested on isolated rat left atria or papillary muscle preparations, OHV A-PLA2 (2.5-20 micrograms/ml) caused positive inotropic effect, followed by contracture. The positive inotropic effects could be abolished by high Ca2+ and enhanced by low Ca2+; both treatments accelerated contracture. The contracture could be inhibited in Mn2+ (5 mM)-containing medium and abolished by Ca(2+)-free bath solution containing 1 mM EDTA. The cardiotoxic action of OHV A-PLA2 was not influenced by verapamil, tetrodotoxin, propranolol, phentolamine, atropine or indomethacin. It is suggested that the cardiotoxic effects of OHV A-PLA2 may result from increasing intracellular levels of Ca2+.

Pharmacokinetics of cytotoxin from Chinese cobra (Naja naja atra) venom

The pharmacokinetics of cytotoxin from Chinese cobra (Naja naja atra) venom was studied in rabbits after i.v. and i.m. injection of 0.2 and 0.5 mg.kg-1, respectively. The plasma levels of the cytotoxin were analysed by a biotin-avidin enzyme-linked immunosorbent assay. The plasma concentration-time course after i.v. administration fitted a two-compartment open model. The half-life (mean +/- S.D.) of the alpha-phase was 5.8 +/- 0.6 min and that of the beta-phase 3.5 +/- 0.2 hr. Apparent volume of distribution was 1.7 +/- 0.3 litres.kg-1, and clearance was 5.6 +/- 1.4 ml.min-1. A rapid absorption was observed after i.m. injection with peak plasma level of 260 +/- 90 ng.ml-1 reached within 13.6 +/- 2.4 min. The absorption rate constant was 0.16 +/- 0.03 ml-1. The area under the plasma concentration-time curve was 33 +/- 15 micrograms.min.ml-1.

[Biotin-avidin-ELISA for cytotoxin purified from cobra venom]

A technique combining the biotin-avidin amplifying system with sandwich enzyme-linked immunosorbent assay (B-A-ELISA) was developed for the microassay of the cytotoxin from Naja naja atra venom. The horse-peroxidase was used as the marker and polystyrene microhemagglutination plates as solid carrier. The sensitivity was 0.5 ng.ml-1. The assay range was 1.25-320 ngml-1 with coefficient of variation of 4.9% (intragroup) and 8.1% (intergroups), respectively.