[Comparison of three dimensional CT venography and ascending phlebography based on propensity score matching in the evaluation of recurrent varicose veins]

Objective: To compare the efficacy of lower extremity three dimensional CT venography (CTV) and lower extremity ascending phlebography in evaluating recurrent varicose veins. Methods: A retrospective analysis was conducted on clinical data from 235 patients with unilateral recurrent varicose veins who were treated at the Department of Vascular Surgery,Beijing Shijitan Hospital,Capital Medical University, between January 2015 and December 2020.There were 112 males and 123 females, with an age of (62.5±11.4)years (range:24 to 75 years).Patients were stratified into two groups based on preoperative imaging examination:the CTV group (utilizing lower extremity venous ultrasound+lower extremity CTV) and the control group (employing lower extremity venous ultrasound+lower extremity ascending phlebography).The two groups were matched in a 1∶1 ratio using propensity score matching, resulting in 43 cases per group.Comparative analyses between the groups at the one-year postoperative follow-up were performed using independent sample t tests, Wilcoxon rank-sum tests, χ2 tests, and linear regression analysis. Results: One year post-surgery,the CTV group exhibited a lower venous clinical severity score (VCSS) compared to the control group(M(IQR),3.0(4.3) vs.4.0(5.8),Z=-2.038,P=0.040).Additionally, the chronic venous insufficiency patients' quality of life questionnaire (CIVIQ-20) scores were significantly higher in the CTV group than in the control group (89.0(8.0) vs.82.5(17.0), Z=-2.627, P=0.010).Patients in the CTV group also experienced a shorter ulcer healing time compared to the control group (4.0(4.0) weeks vs.12.0(7.0) weeks, Z=-3.217,P<0.01).Both groups showed no clinically symptomatic recurrent varicose veins or ulcers.However, they exhibited ultrasound-detectable varicose vein recurrence, with no statistically significant difference (χ2=0.453,P=0.500).The number of diseased vessels requiring management based on ultrasound supplemented by CTV was 16, while the number supplemented by ascending phlebography was 7,with a statistically significant difference (χ2=4.800,P=0.030).Linear regression analysis demonstrated that clinical-etiology-anatomy-pathology clinical grading and the preoperative imaging examination method exerted independent influences on VCSS and CIVIQ-20 during the one-year postoperative assessment. Conclusions: CTV-assisted ultrasound enables a direct and comprehensive evaluation and localization of diseased veins in patients with recurrent varicose veins.The utilization of lower extremity vein ultrasound combined with CTV-guided management of lower extremity vessels in minimally invasive treatment significantly improves patient prognosis, surpassing the assessment provided by ascending phlebography.

[Prognostic analysis of patients with acute leukemia and central nervous system involvement undergoing allogeneic hematopoietic stem cell transplantation]

Objective: To investigate the potential of allogeneic hematopoietic stem cell transplantation (allo-HSCT) in mitigating the adverse prognosis associated with central nervous system leukemia (CNSL) and to assess the significance of prophylactic intrathecal injection. Methods: A retrospective cohort analysis was conducted involving 30 patients with acute leukemia who had a history of CNSL who underwent allo-HSCT at Peking University People's Hospital between September 2012 and March 2018 (referred to as the CNSL-positive group). In addition, 90 patients with acute leukemia were selected from the same period who underwent allo-HSCT without a history of CNSL (referred to as the CNSL-negative group) and a rigorous 1∶3 matching was performed based on disease type, disease status, and transplantation type to form the control group. The prognosis between the two groups was compared using Kaplan-Meier analysis and the high-risk factors for CNSL relapse post-transplant were identified through Cox proportional-hazards model. Results: The median age of patients in the CNSL-negative group was significantly higher than that of patients in the CNSL-positive group (32 years vs. 24 years, P=0.014). No significant differences were observed in baseline data, including sex, disease type, disease status at transplantation, donor-recipient relationship, and human leukocyte antigen consistency between the two groups. The median follow-up time was 568 days (range: 21-1 852 days). The 4-year cumulative incidence of relapse (71.4%±20.9% vs. 29.3%±11.5%, P=0.005) and the cumulative incidence of CNSL post-transplant (33.6%±9.2% vs. 1.2%±1.2%, P<0.001) were significantly higher in the CNSL-positive group than in the CNSL-negative group. Furthermore, the 4-year leukemia-free survival rate in the CNSL-positive group was significantly lower than that in the CNSL-negative group (23.1%±17.0% vs. 71.5%±11.6%, P<0.001). However, no significant differences were observed in the 4-year cumulative transplant-related mortality and overall survival rates between the two groups (both P>0.05). Multivariate analysis revealed that a history of CNSL before transplantation (HR=25.050, 95%CI 3.072-204.300, P=0.003) was identified as high-risk factors for CNSL relapse post-transplant. Conversely, haploidentical transplantation was associated with a reduced risk of CNSL relapse post-transplant (HR=0.260, 95%CI 0.073-0.900, P=0.034). Within the CNSL-positive group, seven patients received prophylactic intrathecal therapy after transplantation, and their CNSL relapse rate was significantly lower than that of the 23 patients who did not receive intrathecal therapy after transplantation (0/7 vs. 9/23, P=0.048). Conclusions: Patients with a history of CNSL have a higher risk of relapse and experience poorer leukemia-free survival following transplantation. The use of prophylactic intrathecal injection shows promise in mitigating CNSL relapse rates, although further validation through prospective studies is necessary to substantiate these observations.

[Long-term efficacy of radiofrequency closure in the treatment of great saphenous vein varicose]

Objective: To examine the long-term efficacy of radiofrequency closure in the treatment of great saphenous vein varicose. Methods: The clinic data of 185 patients with varicose veins of lower limbs treated with radiofrequency closure admitted at Department of Vascular Surgery, Beijing Shijitan Hospital, Capital Medical University from July 2016 to January 2017 was analyzed retrospectively. A total of 203 limbs were treated by radiofrequency closure. The long-term efficacy of radiofrequency closure was evaluated by analyzing the closure rate, clinical-etiology- anatomy-pathophysiology (CEAP) grading, venous clinical severity score (VCSS), chronic venous insufficiency questionnaire (CIVIQ) score, and complications, using repeated measures analysis of variance. Results: All procedures were successful. The closure rate was 98.0% (199/203) at one year and two years postoperative, which was still maintained at 97.5% (198/203) at 3 years of follow-up. Postoperative CEAP grading was significantly downgraded compared with that before the operation. Totally 88.4% (76/86) of C5 to C6 grade patients downgraded to C2 to C4 grade at 6 months, and 95.3% (82/86) downgraded to C0 to C2 garde at 3 years postoperative. VCSS and CIVIQ score in both groups significantly improved at all follow-up time points compared to preoperative scores (VCSS: F=1 064.7, P=0.003; CIVIQ score: F=2 984.3, P=0.001). The most common complication was subcutaneous blood stasis (10.8%), most of which disappeared within 1 month after the surgery. Other complications included pigmentation and thrombophlebitis (5.9% and 3.9%, respectively). Conclusion: The long-term efficacy of radiofrequency closure of the great saphenous vein is satisfactory.

[Role of narrow band imaging in the diagnosis of premalignant and malignant lesions of oral cavity]

Objective: To investigate the role of narrow band imaging (NBI) endoscopy in diagnosing oral premalignant and malignant lesions. Methods: NBI and white light (WLI) endoscopy were performed on 85 patients (47 females, 38 males, aged from 12 to 83 years old, the medium age was 58 years) with 144 oral lesions from July 2016 to October 2017 in the First Affiliated Hospital of Xiamen University. NBI findings were classified into 5 types according to the Ni's classification and compared with histopathological results. Sensitivity, specificity, accuracy, positive predictive value (PPV) and negative predictive value (NPV) of NBI and WLI were calculated. Accuracy of NBI on premalignant and malignant lesions were compared with that of WLI. The connection between NBI findings and pathological results were investigated. SPSS 22.0 software was used to analyze the data. Results: Sensitivity, specificity, PPV, and NPV of NBI vs WLI were 96.5% vs 81.2%, 98.3% vs 98.3%, 98.8% vs 98.6%, and 95.1% vs 78.4%, respectively. NBI findings showed high accordance with the phathological results (kappa=0.943,P<0.01). However, consistency between WLI findings and the phathological results was relatively low (kappa=0.765, P<0.01). NBI was more accurate in diagnosing both premalignant (P<0.01) and malignant lesions (especially for high-grade intraepithelial neoplasia, P<0.01) than WLI. There was remarkable correlation between NBI findings and the phathological results (r=0.836, P<0.01). Conclusions: NBI shows high accuracy in detecting premalignant and malignant lesions of oral cavity. Ni's NBI classification is helpful to diagnose the premalignant and early malignant lesions as well as to evaluate tumor invasion. Thus, NBI can contribute more to early diagnosis and therapy of premalignant and malignant lesions of oral cavity.

[Correlation between(Pro) renin receptor levels and gender and disease severity in patients with obstructive sleep apnea syndrome]

Objective:The aim of this study is to investigate the relationship between the level of (pro) renin(P)RR in obstructive sleep apnea syndrome (OSA) patients, and the gender and disease severity of the disease.b>Method:From March 2010 to March 2018, eighty OSA patients who were treated and diagnosed in our hospital were selected as subjects. Another 20 healthy subjects were selected as the control group.Plasma soluble (pro) renin receptor ［s(P)RR］ levels and clinical parameters were measured in healthy subjects and OSA patients with different sex and disease severity. Result:The plasma s(P)RR concentrations were significantly higher in OSA patients than that in control group. In all patients, plasma s(P)RR concentrations increased with increasing disease levels and showed the same trend between men and women. In addition,in all patients, plasma s(P)RR concentrations were significantly positively correlated with waist-to-hip ratio, HbA1c, AHI, and oxygen desaturation index. There was a significant negative correlation between saturation (MSpO₂) and minimum oxygen saturation (minSpO₂) (P<0.05).In female subjects,plasma s(P)RR concentrations were significantly positively correlated with waist-to-hip ratio and AHI,but significantly negatively correlated with eGFR (P<0.05).In male subjects,plasma s(P)RR concentration was significantly positively correlated with waist-to-hip ratio,HbA1c,renin level,AHI and oxygen desaturation index, but negatively correlated with eGFR, MSpO₂ and minSpO₂ (P<0.05). Plasma s(P)RR concentrations were significantly reduced after treatment with nasal continuous positive airway pressure ventilator. In addition, ESS,AHI,MSpO₂,minSpO₂,and oxygen desaturation index were all significantly improved (P<0.05).Conclusion: Plasma s(P)RR levels in OSA patients are significantly positively correlated with the severity of the disease and can directly reflect the severity of the disease. In addition, the patient with higher waist-to-hip ratio and HbA1c, and lower eGFR can effect plasma s(P)RR levels, and may lead to OSA aggravation.

[Validation of the Caprini risk assessment model for venous thromboembolism in Chinese hospitalized patients in a general hospital]

Objective: To assess the validity of Caprini risk assessment model in prediction of venous thromboembolism in Chinese hospitalized patients in a general hospital. Methods: Medical record review was performed in Beijing Shijitan Hosital for all eligible hospitalized patients who underwent screening for venous thromboembolism between January and December 2015. The Caprini score of patients with or without venous thromboemboilism and incidence of venous thromboembolism in patients with various Caprini risk levels, surgery and medical patients was compared. Results: A total of 6 966 inpatients were enrolled. Three hundred and ninety-six patients developed venous thromboembolism. The Caprini median score of patients with venous thromboemboilism was 5 (3-7), which higher than 3(2-5) of patients without venous thromboembolism(Z=-13.68, P<0.01). Incidence of venous thromboembolism of patients in low, moderate, high, highest risk level was 1.0%, 1.8%, 5.7%, 10.6%, respectively. There was no statistically significant difference of incidence between low and moderate risk patients (OR=1.88, 95%CI: 0.89-3.99, P>0.05), but significant difference between moderate and high risk (OR=3.23, 95%CI: 2.06-5.06, P<0.01), high and highest risk patients (OR=1.97, 95%CI: 1.59-2.45, P<0.01). There was no incidence difference of venous thromboembolism between surgery and medical patients in the same Caprini level of low (χ(2)=3.58 , P>0.05), moderate(χ(2)=2.89, P>0.05), high(χ(2)=0.46, P>0.05), highest risk(χ(2)=1.61, P>0.05). Conclusion: Caprini risk assessment model can effectively predict the occurence of venous thromboembolism in Chinese hospitalized patients with high risk of VTE(Caprini score >2)in a general hospital.

[Role of narrow band imaging in the detection of malignant lesions of the oropharynx and the laryngopharynx]

Objective:To explore the role of narrow band imaging (NBI) endoscopy in the diagnosis of oropharyngeal and laryngopharyngeal lesions. Method:NBI and white light (WLI) endoscopy were performed on 90 patients with oropharyngeal and laryngopharyngeal lesions from August 2016 to May 2017. NBI findings were classified into 5 types according to the Ni classification and were compared with histopathological results. Accuracy of NBI on premalignant and malignant lesions were compared with WLI. The connection between NBI findings and phathological results were explored. Result:Sensitivity, specificity, PPV, and NPV of NBI vs WLI were 988% vs 83.7%, 89.2% vs 86.5%, 95.5% vs 93.5%, and 97.1% vs 69.6%, respectively NBI findings were highly consistent with the phathological results (kappa=0.901,P<0.01). However, consistency between WLI findings and the phathological results was relatively low (kappa=0.657,P<0.01). NBI was more accurate in diagnosing both premalignant (P<0.01) and malignant lesions (especially for high-grade intraepithelial neoplasia, (P<0.01) than WLI. NBI findings correlated with the phathological results (r=0.820, P<0.01). Conclusion:NBI shows high accuracy in detecting premalignant and malignant lesions of oropharynx and laryngopharynx; Ni's NBI classification helps to diagnose the premalignant and early malignant lesions and evaluate tumor invasion. Thus, NBI can contribute more in the diagnosis and minimally invasive treatment of premalignant and malignant lesions of oropharynx and laryngopharynx.

[The study of nomogram based on Ishak inflammation score for recurrence of hepatocellular carcinoma after curative resection]

Objective: To investigate the correlation between Ishak inflammation score and the clinicopathological characteristics and recurrence of patients with hepatocellular carcinoma (HCC) after curative resection, and then set up a recurrence nomogram for HCC. Methods: A total of 326 patients with HCC after curative resection from January 2006 to December 2009 were studied retrospectively as training cohort and 110 HCC patients after surgery from January 2010 to December 2012 were used as validation cohort.Clinical follow-up data and peritumoral Ishak inflammation score in training cohort were used to set up a nomogram predicting recurrence of HCC, which was verified by validation cohort. Kaplan-Meier and Cox proportional hazard regression model were used to analyzed accuracy of model prediction. Results: According to Ishak inflammation score, patients were divided into four subgroups: Grade Ⅰ(1-4 scores), Grade Ⅱ(5-8 scores), Grade Ⅲ (9-12 scores) and Grade Ⅳ(13-18 scores). Ishak inflammation score were associated with aspartate transaminase(median 36.0 U/L, P=0.011), γ-glutamyl transpeptidase(median 54.5 U/L, P=0.005), HBV-DNA load(20.5%>10(6) copies/ml, P=0.015) and microvascular invasion(26.7% positive, P=0.021). Multivariate analysis showed that Ishak inflammation score(P=0.007), HBV-DNA load(P<0.01), tumor size(P=0.001) and microvascular invasion(P=0.001) were related with the recurrence of HCC patients.These four risk factors were incorporated into the nomogram.Calibration curves of the nomogram had good agreement between prediction and observation in the probability of recurrence.Both C-indexes and receiver operating characteristic curve analyses revealed that this nomogram had better predictive abilities than those of the AJCC and Barcelona Clinic Liver Cancer (BCLC) stage systems.These results were verified by the validation cohort. Conclusion: A nomogram based on Ishak inflammation score could accurately predict the recurrence of HCC and contribute to HCC relapse surveillance after curative hepatectomy.

[Expression of Brain Natriuretic Peptide in Myocardial Tissue of Sudden Cardiac Death and Non-sudden Cardiac Death]

OBJECTIVES

To study the expression pattern of brain natriuretic peptide （BNP） in myocardial tissue from forensic routine cases and to explore its application value in the forensic determination of sudden cardiac death （SCD）.

METHODS

The data of 96 autopsy cases accepted by the center of Medico-legal Investigation of China Medical University between December 2008 to May 2014 were collected. There were 62 cases in SCD group cardiac and 34 cases in non-SCD group. The myocardial tissues were taken from left and right ventricular wall, respectively. The expressions of BNP protein and BNP mRNA in myocardial tissue were detected by HE staining, immunohistochemical staining, Western blotting and quantitative real-time reverse transcription-polymerase chain reaction （RT-qPCR）, etc.

RESULTS

The immunohistochemical staining of myocardial tissue showed diffusely positive staining in SCD group, and patchily or diffusely positive staining in non-SCD group with lighter degree. The result of Western blotting showed that the expression of BNP protein elevated in left ventricular wall of SCD group. The result of RT-qPCR showed a positive correlation between the BNP mRNA expressions in bilateral ventricular walls and the heart weight, bilateral lung weight, and N-terminal prohormone of brain natriuretic peptide （NT-proBNP） concentration. There were large differences between the BNP mRNA concentrations in SCD group and non-SCD group, and the former was statistically higher （P<0.05）.

CONCLUSIONS

The expressions of BNP protein and BNP mRNA in myocardial tissue are related to the causes of death. Combined with pathological changes, the expressions of BNP protein and BNP mRNA in myocardial tissue have certainly practical significance for the determination of SCD and the analysis of the death mechanism in the cases related to forensic pathology.

[The Changes of HIF-1α and VEGF-A in Myocardial Tissue of Rats with Arrhythmias]

OBJECTIVES

To observe the expression changes of hypoxia inducible factor-1α（HIF-1α） and vascular endothelial growth factor-A （VEGF-A） in rats with arrhythmias, and to explore the differences of the expression pattern in the two indicators of acute myocardial ischemia caused by arrhythmias and coronary insufficiency.

METHODS

The arrhythmia was induced by CaCl₂, and the expression changes of HIF-1α and VEGF-A were detected by immunohistochemistry, Western blotting and real-time PCR within 6 h after the arrhythmia in rats.

RESULTS

The expression of HIF-1α and VEGF-A showed diffuse in the myocardial tissue of rats died from arrhythmias. Both of them increased in the early arrhythmia, then decreased. Extensive myocardial ischemia happened at the beginning of arrhythmia occurrence and its range didn't expand with time.

CONCLUSIONS

The expressions of HIF-1α and VEGF-A in myocardium of the rats with arrhythmia can provide evidence for the differential diagnosis of acute myocardial ischemia caused by fatal arrhythmia and coronary insufficiency.

[Application of narrow band imaging in the detection of premalignant and malignant lesions of the larynx]

Objective: To evaluate the role of narrow band imaging (NBI) endoscopy in the diagnosis of laryngeal lesions. Methods: A total of 136 patients with laryngeal lesions were examined by NBI and white light (WLI) endoscopy from July 2016 to May 2017. Sensitivity, specificity, accuracy, and positive predictive value (PPV) and negative predictive value (NPV) of NBI and WLI were calculated. SPSS 20.0 software was used to analyze the data. Results: Compared to WLI, NBI showed higher sensitivity (94.9% vs 83.3%), specificity (95.6% vs 84.4%), PPV (94.9% vs 82.3%), and NPV (95.6% vs 85.4%). There was high consistency of the results etween NBI and pathology (kappa=0.904, P<0.01). However, consistency of the findings between WLI and pathology was relatively weak (kappa=0.677, P<0.01). NBI showed the higher accuracy in diagnoses of both benign lesions (especially for premalignant lesions, P<0.01) and malignant lesions (especially for high-grade intraepithelial neoplasia, P<0.05) than WLI. NBI findings correlated with the pathological results (r=0.739, P<0.01). Conclusions: NBI demonstrates higher accuracy in the detection of premalignant and malignant lesions of the larynx.

[Clinical value of PCR for viral detection of bronchoalveolar lavage fluid in the diagnosis and treatment of pneumonia after allogeneic hematopoietic stem cell transplantation]

Objective: To analyze the clinical value of real-time PCR for virus detection in the diagnosis and treatment of patients after allo-HSCT who had no infection evidence of pneumonia using routine pathogen detection panel. Methods: The clinical data of 71 episodes with acute lung injury from May 2015 to March 2017 after allo-HSCT in hematology department of Peking University People's Hospital (PKUPH) were retrospectively analyzed. PCR for virus detection and other routine pathogen detection tests were performed on bronchoalveolar lavage fluid (BALF) samples. Results: Among 71 episodes with acute lung injury, a total of 15 patients were diagnosed as lower respiratory tract disease merely associated with virus (detection rate of 21.13%) , 19 episodes were absent of lower respiratory tract infection. The median time from allo-HSCT to the occurrence of lung injury were 176 (49-1 376) d and 196 (57-457) d respectively (z=-0.191, P=0.864) . There were no statistical differences for baseline characteristics and clinical features between two groups. The 100-day attributable mortalities were 13.3% (2/15) and 26.3% (5/19) (χ(2)=0.864, P=0.426) . Patients with low-dose steroids treatment had favorable outcome than those with high-dose steroids treatment (the dose of methylprednisolone ≥250 mg/d as standard) [4.2% (1/24) vs 60.0% (6/10) ]. In patients with detectable virus in BALF, 2 patients died with early high-dose steroids treatment, while 11 patients survived with no steroids treatment or late application. Conclusions: Virus infection should be considered in post-HSCT pneumonia patient with negative result using routine pathogen detection panel. Expanding virus detection panel by PCR in BALF could increase diagnostic precision and might be instructive to treatment.

[Analysis of the influence of iron overload in glucose metabolism in thalassemia major patients]

Objective: This study aimed at determining the characteristics of the glucose homeostasis and its relationship with iron overload of the patients with β-thalassemia major (β-TM). Method: From Sun Yat-sen Memorial Hospital between January 2014 and December 2015, a total of 57 transfusion-dependent β-TM patients with 5-18 years old were enrolled in this study and fasting blood glucose(FBG) and insulin level, serum ferritin (SF), serum iron, transferrin, total iron binding capacity, unsaturated iron binding capacity were determined.Insulin resistance index (IRI), insulin sensitivity index and β-cell function index (BFI) were also estimated. Besides, in 36 patients cardiac T2* and liver T2* were estimated. Result: (1) Four patients(7%) with β-TM were diagnosed diabetes mellitus, and 14(24%) had impaired fasting glucose. (2) The incidence of abnormal glucose metabolism was significantly different according to levels of SF and degrees of the cardiac iron overload(χ(2)=9.737, P<0.05; χ(2)=17.027, P<0.05). It rose while the level of SF increased and the degree of cardiac iron overload aggravated. (3) The incidence of abnormal glucose level was not significantly different in cases with different degree of liver iron overload.The severe group of liver iron overload had significantly higher levels of INS, HOMA-βFI, HOMA-ISI, HOMA-βFI than the non-severe group (Z=-2.434, -2.515, F=8.658, all P<0.05), while no differences were found in the level of FBG, HOMA-βFI between two groups. (4) The result of logistic regression analysis indicated that the cardiac T2* was a significant predictor for the incidence of abnormal glucose metabolism in TM patients (P=0.035, OR=1.182%, 95%CI=1.048 to 1.332). Conclusion: The high prevalence of abnormal glucose metabolism in β-TM patients was mainly closely related with the internal iron overload, especially in organs.The cardiac T2* was an independent risk factor for the incidence of abnormal glucose metabolism in TM patients.

Study of cardiovascular function using a coupled left ventricle and systemic circulation model

To gain insight into cardio-arterial interactions, a coupled left ventricle-systemic artery (LV–SA) model is developed that incorporates a three-dimensional finite-strain left ventricle (LV), and a physiologically-based one-dimensional model for the systemic arteries (SA). The coupling of the LV model and the SA model is achieved by matching the pressure and the flow rate at the aortic root, i.e. the SA model feeds back the pressure as a boundary condition to the LV model, and the aortic flow rate from the LV model is used as the input for the SA model. The governing equations of the coupled system are solved using a combined immersed-boundary finite-element (IB/FE) method and a Lax–Wendroff scheme. A baseline case using physiological measurements of healthy subjects, and four exemplar cases based on different physiological and pathological scenarios are studied using the LV–SA model. The results of the baseline case agree well with published experimental data. The four exemplar cases predict varied pathological responses of the cardiovascular system, which are also supported by clinical observations. The new model can be used to gain insight into cardio-arterial interactions across a range of clinical applications.

Relationship between vitamin D receptor (VDR) polymorphisms and the efficacy of recombinant human growth hormone (rhGH) treatment in children with idiopathic short stature

Polymorphisms in the vitamin D receptor (VDR) gene are associated with idiopathic short stature (ISS) in several countries. This study aimed to identify a possible correlation between polymorphisms in the VDR promoter in Chinese children with ISS and the efficacy of the recombinant human growth hormone (rhGH) treatment. Pre-pubertal children with ISS and healthy age- and gender-matched children (N = 95 each) were enrolled in this study. Two single nucleotide polymorphisms (SNPs) in the VDR promoter (rs11568820 at the Cdx-2-binding site upstream of exon 1e and rs4516035 at -1012 upstream of exon 1a) were typed. The growth velocity, standard deviation score (SDS) of height for chronological age, height SDS for bone age, predicted adult height, and serum insulin-like growth factor 1 (IGF-1) and IGF-binding protein 3 (IGFBP-3) levels of the ISS patients were determined before and 6 months after rhGH treatment. No significant differences were observed in the genotype frequencies between the ISS cases and controls. After rhGH treatment, the growth velocity of the A/G genotype at the Cdx-2-binding site SNP locus was significantly higher than that of the G/G genotype; the IGF-1 and IGFBP-3 levels were also higher in the treated group than the untreated group. However, these changes were independent of the VDR-promoter genotype. Polymorphisms in the VDR promoter may not result in the pathogenesis of ISS in Chinese children. The A/G genotype showed a significantly higher growth velocity than the G/G genotype, and may represent a short-term marker of growth potential.

Parameter estimation in a Holzapfel-Ogden law for healthy myocardium

A central problem in biomechanical studies of personalized human left ventricular (LV) modelling is to estimate material properties from in vivo clinical measurements. In this work we evaluate the passive myocardial mechanical properties inversely from the in vivo LV chamber pressure-volume and strain data. The LV myocardium is described using a structure-based orthotropic Holzapfel-Ogden constitutive law with eight parameters. In the first part of the paper we demonstrate how to use a multi-step non-linear least-squares optimization procedure to inversely estimate the parameters from the pressure-volume and strain data obtained from a synthetic LV model in diastole. In the second part, we show that to apply this procedure to clinical situations with limited in vivo data, additional constraints are required in the optimization procedure. Our study, based on three different healthy volunteers, demonstrates that the parameters of the Holzapfel-Ogden law could be extracted from pressure-volume and strain data with a suitable multi-step optimization procedure. Although the uniqueness of the solution cannot be addressed using our approaches, the material response is shown to be robustly determined.

Dosage assessment of valnemulin in pigs based on population pharmacokinetic and Monte Carlo simulation

To estimate the valnemulin pharmacokinetic profile in a swine population and to assess a dosage regimen for increasing the likelihood of optimization. This study was, respectively, performed in 22 sows culled by p.o. administration and in 80 growing-finishing pigs by i.v. administration at a single dose of 10 mg/kg to develop a population pharmacokinetic model and Monte Carlo simulation. The relationships among the plasma concentration, dose, and time of valnemulin in pigs were illustrated as C(i,v) = X(0 )(8.4191 × 10(-4) × e(-0.2371t) + 1.2788 × 10(-5) × e(-0.0069t)) after i.v. and C(p.o) = X(0) (-8.4964 × 10(-4) × e(-0.5840t) + 8.4195 × e(-0.2371t) + 7.6869 × 10(-6) × e(-0.0069t)) after p.o. Monte Carlo simulation showed that T(>MIC) was more than 24 h when a single daily dosage at 13.5 mg/kg BW in pigs was administrated by p.o., and MIC was 0.031 mg/L. It was concluded that the current dosage regimen at 10-12 mg/kg BW led to valnemulin underexposure if the MIC was more than 0.031 mg/L and could increase the risk of treatment failure and/or drug resistance.

Diagnostic accuracy of atopy patch tests for food allergy in children with atopic dermatitis aged less than two years

BACKGROUND

Atopy patch tests (APT) have been introduced as a valuable tool for the diagnosis of food allergy. However, interpretation of the readout of APT requires further clarification.

OBJECTIVE

To investigate the accuracy of APT in identifying atopic sensitisation to hen's eggs (HE), cow's milk (CM), soybean and wheat in Chinese children with atopic dermatitis (AD) aged less than two years and to evaluate skin signs of APT for accurate diagnosis of food allergy.

METHODS

APT was performed and food allergy confirmed by open oral food challenges with HE, CM, soybean and wheat in 150 Chinese AD children aged less than two years. The sensitivity, specificity, positive (PPV) and negative (NPV) predictive values, positive (LR+) and negative likelihood ratio (LR-) of APT were calculated.

RESULTS

Erythema and infiltration were not sufficiently indicative of a positive APT. The PPV increased with the appearance of indurations and the number of papules. The true positive APT rate increased from scores of + to +++. The PPV and specificity were 100% while APT scores of +++ were obtained with HE, CM and wheat. The sensitivity of APT with HE, CM, soybean and wheat allergy ranged from 59.6% to 90.5%, while the specificity ranged from 82.1% to 92.4%.

CONCLUSION

The APT is a suitable method for the diagnosis of AD in Chinese children aged less than two years with food allergies. Erythema and infiltration are not sufficient indicators of APT positivity. The PPV increases with indurations and the number of papules.

Changes in graves' ophthalmopathy after radioiodine and anti-thyroid drug treatment of Graves' disease from 2 prospective, randomized, open-label, blinded end point studies

AIMS

A significant association between radioiodine therapy (RIT) and the development or the worsening of pre-existing Graves' ophthalmopathy (GO) has been reported. This post-hoc analysis of 2 studies attempted to describe the changes observed in pre-existing or new-onset GO following RIT with the goal of euthyroidism rather than hypothyroidism and to describe the relationship GO changes and the final outcome.

PATIENTS AND METHODS

In 2 prospective, randomized open-label blinded endpoint trials, patients received radioiodine alone; or, patients received radioiodine or antithyroid drug therapy (ATD). The severity and activity of GO were assessed during a 9-12-year follow-up. The study end points in study 1 were euthyroidism, hyperthyroidism, hypothyroidism, and changes in GO. In study 2, the end points were euthyroidism, hyperthyroidism, hypothyroidism, relapse, and changes in GO.

RESULTS

Both RIT and ATD were associated with worsening GO and new-onset GO. Both RIT and ATD led to similar aggravation of pre-existing GO or the development to new-onset GO. After RIT or ATD, the euthyroid patients (without levothyroxine substitution) demonstrated an improvement in GO, with 78-89% patients with preexisting GO exhibiting improvement, whereas hyperthyroid, hypothyroid and relapsed patients had worsening or new-onset GO.

CONCLUSIONS

Thyroid function is a dominant risk factor. Thyroid function may be the most important determinant in worsening or new-onset GO in both the natural disease course and in treated patients, independent of the kind of treatment. Therefore, we recommend euthyroidism as a goal of treatment.

Structure-based finite strain modelling of the human left ventricle in diastole

Finite strain analyses of the left ventricle provide important information on heart function and have the potential to provide insights into the biomechanics of myocardial contractility in health and disease. Systolic dysfunction is the most common cause of heart failure; however, abnormalities of diastolic function also contribute to heart failure, and are associated with conditions including left ventricular hypertrophy and diabetes. The clinical significance of diastolic abnormalities is less well understood than systolic dysfunction, and specific treatments are presently lacking. To obtain qualitative and quantitative information on heart function in diastole, we develop a three-dimensional computational model of the human left ventricle that is derived from noninvasive imaging data. This anatomically realistic model has a rule-based fibre structure and a structure-based constitutive model. We investigate the sensitivity of this comprehensive model to small changes in the constitutive parameters and to changes in the fibre distribution. We make extensive comparisons between this model and similar models that employ different constitutive models, and we demonstrate qualitative and quantitative differences in stress and strain distributions for the different constitutive models. We also provide an initial validation of our model through comparisons to experimental data on stress and strain distributions in the left ventricle.

A Quasi-Nonlinear Analysis of the Anisotropic Behaviour of Human Gallbladder Wall

Estimation of biomechanical parameters of soft tissues from noninvasive measurements has clinical significance in patient-specific modeling and disease diagnosis. In this work, we present a quasi-nonlinear method that is used to estimate the elastic moduli of the human gallbladder wall. A forward approach based on a transversely isotropic membrane material model is used, and an inverse iteration is carried out to determine the elastic moduli in the circumferential and longitudinal directions between two successive ultrasound images of gallbladder. The results demonstrate that the human gallbladder behaves in an anisotropic manner, and constitutive models need to incorporate this. The estimated moduli are also nonlinear and patient dependent. Importantly, the peak stress predicted here differs from the earlier estimate from linear membrane theory. As the peak stress inside the gallbladder wall has been found to strongly correlate with acalculous gallbladder pain, reliable mechanical modeling for gallbladder tissue is crucial if this information is to be used in clinical diagnosis.

A physiologically based pharmacokinetic model for valnemulin in rats and extrapolation to pigs

A flow-limited, physiologically based pharmacokinetic (PBPK) model for predicting the plasma and tissue concentrations of valnemulin after a single oral administration to rats was developed, and then the data were extrapolated to pigs so as to predict withdrawal interval in edible tissues. Blood/tissue pharmacokinetic data and blood/tissue partition coefficients for valnemulin in rats and pigs were collected experimentally. Absorption, distribution and elimination of the drug were characterized by a set of mass-balance equations. Model simulations were achieved using a commercially available software program. The rat PBPK model better predicted plasma and tissue concentrations. The correlation coefficients of the predicted and experimentally determined values for plasma, liver, kidney, lung and muscle were 0.96, 0.94, 0.96, 0.91 and 0.91, respectively. The rat model parameters were extrapolated to pigs to estimate valnemulin residue withdrawal interval in edible tissues. Correlation (R(2) ) between predicted and observed liver, kidney and muscle were 0.95, 0.97 and 0.99, respectively. Based on liver tissue residue profiles, the pig model estimated a withdrawal interval of 10 h under a multiple oral dosing schedule (5.0 mg/kg, twice daily for 7.5 days). PBPK models, such as this one, provide evidence of the usefulness in interspecies PK data extrapolation over a range of dosing scenarios and can be used to predict withdrawal interval in pigs.

Experimental Investigation of the Flow of Bile in Patient Specific Cystic Duct Models

Three-dimensional scaled-up transparent models of three human cystic ducts were prepared on the basis of anatomical specimens. The measurement of pressure drop across the cystic duct models and visualization of the flow structures within these ducts were performed at conditions replicating the physiological state. The flow visualization study confirmed the laminar nature of the flow of bile inside the cystic duct and values of pressure drop coefficient (Cp) decreased as the Reynolds number (Re) increased. The three tested models showed comparable behavior for the curve of Reynolds number versus the pressure drop coefficient. The results show that the tested cystic ducts have both increased pressure drop and complicated flow structures when compared with straight conduits. High resistance in a cystic duct may indicate that the gallbladder has to exert large force in expelling bile to the cystic duct. For patients with diseased gallbladder, and even in healthy persons, gallbladder is known to stiffen with age and it may lose its compliance or flexibility. A high resistance cystic duct coupled with a stiffened gallbladder may result in prolonged stasis of bile in the gallbladder, which is assumed to encourage the formation of gallstones.

Summary report of action research on occupational rehabilitation and community re-integration of migrant workers with work injuries in Mainland China

This article is a summary of an action research exploring the strategies to initiate the occupational rehabilitation and community re-integration of migrant workers with work injuries in Guangdong Province, China. Using two cases of rehabilitation intervention for workers with work injury, a case management model of occupational rehabilitation and community re-integration was illustrated, in the different phases of rehabilitation. Finally, some key elements in supporting occupational rehabilitation and community re-integration for migrant workers with work injury in China were highlighted.

Correlation of Mechanical Factors and Gallbladder Pain

Acalculous biliary pain occurs in patients with no gallstones, but is similar to that experienced by patients with gallstones. Surgical removal of the gallbladder (GB) in these patients is only successful in providing relief of symptoms to about half of those operated on, so a reliable pain-prediction model is needed. In this paper, a mechanical model is developed for the human biliary system during the emptying phase, based on a clinical test in which GB volume changes are measured in response to a standard stimulus and a recorded pain profile. The model can describe the bile emptying behaviour, the flow resistance in the biliary ducts, the peak total stress, including the passive and active stresses experienced by the GB during emptying. This model is used to explore the potential link between GB pain and mechanical factors. It is found that the peak total normal stress may be used as an effective pain indicator for GB pain. When this model is applied to clinical data of volume changes due to Cholecystokinin stimulation and pain from 37 patients, it shows a promising success rate of 88.2% in positive pain prediction.

Pilot project in developing community rehabilitation service for migrant workers suffering from pneumoconiosis in Mainland China

Pneumoconiosis is one of the major occupational health problems in China and increasing numbers of migrant workers suffered from this occupational disease after working in a dusty environment for few years. These migrant workers panicked after being diagnosed as suffering from pneumoconiosis and facing physiological disturbances including progressive dyspnea, respiratory failure or complications like silico-tuberculosis after their return to their rural village. This article reviews the preliminary results of a community rehabilitation pilot project conducted in a rural village in Guizhou, one of the provinces in southwest China. It shares the joint effort of professionals from Guangdong Province and Hong Kong SAR on supporting the migrant workers to manage and cope with this occupational disease. Finally, strategies including early intervention were suggested to help migrant workers to manage the disease. Most importantly, occupational health promotion and prevention were urged as the measures of utmost importance in reducing the risk for migrant workers suffering from pneumoconiosis.

One-dimensional models of the human biliary system

This paper studies two one-dimensional models to estimate the pressure drop in the normal human biliary system for Reynolds number up to 20. Excessive pressure drop during bile emptying and refilling may result in incomplete bile emptying, leading to stasis and subsequent formation of gallbladder stones. The models were developed following the group's previous work on the cystic duct using numerical simulations. Using these models, the effects of the biliary system geometry, elastic property of the cystic duct, and bile viscosity on the pressure drop can be studied more efficiently than with full numerical approaches. It was found that the maximum pressure drop occurs during bile emptying immediately after a meal, and is greatly influenced by the viscosity of the bile and the geometric configuration of the cystic duct, i.e., patients with more viscous bile or with a cystic duct containing more baffles or a longer length, have the greatest pressure drop. It is found that the most significant parameter is the diameter of the cystic duct; a 1% decrease in the diameter increases the pressure drop by up to 4.3%. The effects of the baffle height ratio and number of baffles on the pressure drop are reflected in the fact that these effectively change the equivalent diameter and length of the cystic duct. The effect of the Young's modulus on the pressure drop is important only if it is lower than 400 Pa; above this value, a rigid-walled model gives a good estimate of the pressure drop in the system for the parameters studied.

Modelling chorded prosthetic mitral valves using the immersed boundary method

The Immersed Boundary (IB) Method is an efficient method of modelling fluid structure interactions. However, it has two main limitations: ease of use and ability to model static loading. In this paper, the method is developed, so that it can efficiently and easily model any multileaflet elastic structure. The structure may include chordae, which attach to the leaflets and continue through the leaflet surfaces. In addition, an external surface pressure may be applied to the leaflets, thus enabling the deformations that arise under steady loads to be solved. This method is validated for a model of the native mitral valve under systolic loading and for a prosthetic aortic valve under static loading. It is then applied to a new chorded prosthetic mitral valve, housed in a cylindrical tube, subject to a physiological periodic fluid flow. Results are compared with those obtained by using the commercial package ANSYS as well as with experimental measurements. Qualitative agreements are obtained. There are some discrepancies due to the current IB method being unable to model bending and shear behaviour. In particular, the fibre structures of the new prosthetic valve model developed using the IB method may be prone to crimping. Further development of the IB method is necessary to include bending effects. This will improve the accuracy of both the dynamic and static analysis.

Dynamic modelling of prosthetic chorded mitral valves using the immersed boundary method

Current artificial heart valves either have limited lifespan or require the recipient to be on permanent anticoagulation therapy. In this paper, effort is made to assess a newly developed bileaflet valve prosthesis made of synthetic flexible leaflet materials, whose geometry and material properties are based on those of the native mitral valve, with a view to providing superior options for mitral valve replacement. Computational analysis is employed to evaluate the geometric and material design of the valve, by investigation of its mechanical behaviour and unsteady flow characteristics. The immersed boundary (IB) method is used for the dynamic modelling of the large deformation of the valve leaflets and the fluid-structure interactions. The IB simulation is first validated for the aortic prosthesis subjected to a hydrostatic loading. The predicted displacement fields by IB are compared with those obtained using ANSYS, as well as with experimental measurements. Good quantitative agreement is obtained. Moreover, known failure regions of aortic prostheses are identified. The dynamic behaviour of the valve designs is then simulated under four physiological pulsatile flows. Experimental pressure gradients for opening and closure of the valves are in good agreement with IB predictions for all flow rates for both aortic and mitral designs. Importantly, the simulations predicted improved physiological haemodynamics for the novel mitral design. Limitation of the current IB model is also discussed. We conclude that the IB model can be developed to be an extremely effective dynamic simulation tool to aid prosthesis design.

Investigation of the functional three-dimensional anatomy of the human cystic duct: a single helix?

Clinical research into the formation of gallstones has indicated that the anatomy of the cystic duct is one of a number of factors contributing to the formation of gallstones. The cystic duct allows low-viscosity hepatic bile to enter the gallbladder under low pressure and the expulsion of a more viscous gallbladder bile, but little is known about this transport mechanism and the effect of anatomical variations in structure. This article describes the variation in geometry of the cystic duct, obtained from acrylic resin casts of the neck and first part of the cystic duct in gallbladders removed for gallstone disease and obtained from patients undergoing partial hepatectomy for metastatic disease. The data obtained allowed us to formulate a number of standard terms for describing cystic duct morphology and demonstrate that the term "spiral valve" is only partially correct when describing the duct anatomy. In over half of the casts, spiraling was not the dominant feature of the cystic duct. Additionally, the term valve implies active resistance to flow in one direction, whereas the internal baffles of the cystic duct would serve to regulate bile flow in both directions. These data are useful for realistic 3D modeling of fluid-structure interactions of the flow of bile in the human cystic duct.

Snoring source identification and snoring noise prediction

This paper investigates the snoring mechanism of humans by applying the concept of structural intensity to a three-dimensional (3D) finite element model of a human head, which includes: the upper part of the head, neck, soft palate, hard palate, tongue, nasal cavity and the surrounding walls of the pharynx. Results show that for 20, 40 and 60Hz pressure loads, tissue vibration is mainly in the areas of the soft palate, the tongue and the nasal cavity. For predicting the snoring noise level, a 3D boundary element cavity model of the upper airway in the nasal cavity is generated. The snoring noise level is predicted for a prescribed airflow loading, and its range agrees with published measurements. These models may be further developed to study the various snoring mechanisms for different groups of patients.

The flow of bile in the human cystic duct

Clinical studies suggest that the flow of bile in the biliary system may be a contributing factor in the pathogenesis of cholelithiasis, but little is known about its transport mechanism. This paper reports a numerical study of steady flow in human cystic duct models. In order to obtain parametric data on the effects of various anatomical features in the cystic duct, idealised models were constructed, first with staggered baffles in a channel to represent the valves of Heister and lumen. The qualitative consistency of these findings are validated by modelling two of the real cystic ducts obtained from operative cholangiograms. Three-dimensional (3D) models were also constructed to further verify the two-dimensional (2D) results. It was found that the most significant geometric parameter affecting resistance is the baffle clearance (lumen size), followed by the number of baffles (number of folds in the valves of Heister), whilst the least significant ones are the curvature of the cystic duct and the angle between the neck and the gallbladder. The study presented here forms part of a larger project to understand the functions of the human cystic duct, especially the influence of its various anatomical structures on the resistance to bile flow, so that it may aid the assessment of the risk of stone formation in the gallbladder.

LES modelling of flow in a simple airway model

Detailed information about the flow field pattern is highly important in accurately predicting particle deposition sites in the human airway. Flow in the upper airway during heavy breathing can have a Reynolds number as high as 9300, and therefore presents turbulent features. Although turbulence is believed to have an important effect on the airflow and other transport processes in the bronchial tree, to date both theoretical and numerical studies have predominantly assumed the flow to be laminar. In this paper, transitional/turbulent flow during inspiration is studied using a large eddy simulation (LES) in a single asymmetric bifurcation model of human upper airway. The influence of the non-laminar flow on the patterns and the particle paths is investigated in both 2D and 3D models. Throughout the investigation, comparisons with the laminar and conventional k- models for the same configuration and flow conditions are made. The LES model is also carefully validated against published experimental data in a stenotic tube model. The results demonstrate that the LES model is capable of capturing instantaneous eddy formation and flow separation in (almost) laminar, transitional and turbulent flow regimes, and hence may be used as a powerful and practical tool to provide much of the detailed flow information required for tracing the particle trajectories and particle deposition in human airways.

Geometrical Stress-Reducing Factors in the Anisotropic Porcine Heart Valves

This study carries out a detailed parameter study based on a nonlinear anisotropic finite-element model published previously. The aim of this study is to identify the stress-reducing influences from geometrical parameters such as stent height, valve diameter, and the nonuniform thickness of porcine aortic valves under static loading condition. The anisotropy of the valve is considered to be transversely isotropic with fibers oriented along the circumferential directions, which enables us to use a simple anisotropic constitutive model using uniaxial experimental data. The results showed that in general, higher stent height and smaller diameter combined with nonuniform thickness give rise to a much more reduced overall stress level. Although the absolute values of the peak stresses may be influenced by the detailed orientations of fibers, the trends of the stress variation with the geometrical factors seem to be qualitatively consistent within the parameter ranges considered.

A nonlinear anisotropic model for porcine aortic heart valves

The anisotropic property of porcine aortic valve leaflet has potentially significant effects on its mechanical behaviour and the failure mechanisms. However, due to its complex nature, testing and modelling the anisotropic porcine aortic valves remains a continuing challenge to date. This study has developed a nonlinear anisotropic finite element model for porcine heart valves. The model is based on the uniaxial experimental data of porcine aortic heart valve leaflet and the properties of nonlinear composite material. A finite element code is developed to solve this problem using the 8-node super-parameter nonlinear shells and the update Lagrangian method. The stress distribution and deformation of the porcine aortic valves with either uniform and non-uniform thicknesses in closed phase and loaded condition are calculated. The results showed significant changes in the stress distributions due to the anisotropic property of the leaflets. Compared with the isotropic valve at the same loading condition, it is found that the site of the peak stress of the anisotropic leaflet is different; the maximum longitudinal normal stress is increased, but the maximum transversal normal stress and in-plane shear stress are reduced. We conclude that it is very important to consider the anisotropic property of the porcine heart valves in order to understand the failure mechanism of such valves in vivo.

Gene silencing: double-stranded RNA mediated mRNA degradation and gene inactivation

The recent development of gene transfer approaches in plants and animals has revealed that transgene can undergo silencing after integration in the genome. Host genes can also be silenced as a consequence of the presence of a homologous transgene. More and more investigations have demonstrated that double-stranded RNA can silence genes by triggering degradation of homologous RNA in the cytoplasm and by directing methylation of homologous nuclear DNA sequences. Analyses of Arabidopsis mutants and plant viral suppressors of silencing are unraveling RNA-silencing mechanisms and are assessing the role of methylation in transcriptional and posttranscriptional gene silencing. This review will focus on double-stranded RNA mediated mRNA degradation and gene inactivation in plants.

Aflatoxins and fumonisins in corn from the high-incidence area for human hepatocellular carcinoma in Guangxi, China

A comparative study on the natural occurrence of aflatoxins and Fusarium toxins was conducted with corn samples from high- and low-incidence areas for human primary hepatocellular carcinoma (PHC) in Guangxi, China. In samples from the high-risk area, aflatoxin B(1) was the predominant toxin detected in terms of quantity and frequency, with its concentration ranging between 9 and 2496 microg/kg and an 85% incidence of contamination. Among the samples, 13 (76%) exceeded the Chinese regulation of 20 microg/kg for aflatoxin B(1) in corn and corn-based products intended for human consumption. Significant differences in aflatoxin B(1), B(2), and G(1) and total aflatoxin concentrations in corn between the areas were found (P < 0.05). The average daily intake of aflatoxin B(1) from corn in the high-risk area was 184.1 microg, and the probable daily intake is estimated to be 3.68 microg/kg of body weight/day, 3.20 times the TD(50) in rats. Corn samples from both areas were simultaneously contaminated with fumonisins B(1), B(2), and B(3). Aflatoxin B(1) may play an important role in the development of PHC in Guangxi.

Death the Fas way: regulation and pathophysiology of CD95 and its ligand

Apoptotic cell death mediated by the members of the tumor necrosis factor receptor family is an essential process involved in the regulation of cellular homeostasis during development, differentiation, and pathophysiological conditions. Among the cell death receptors comprising the tumor necrosis factor receptor superfamily, CD95/APO-1 (Fas) is the best characterized. The specific interaction of Fas with its cognate ligand, Fas ligand (FasL), elicits the activation of a death-inducing caspase (cysteine aspartic acid proteases) cascade, occurring in a transcription-independent manner. Caspase activation executes the apoptosis process by cleaving various intracellular substrates, leading to genomic DNA fragmentation, cell membrane blebbing, and the exposure of phagocytosis signaling molecules on the cell surface. Recent studies have shown that the Fas/FasL pathway plays an important role in regulating the life and death of the immune system through activation-induced cell death. In addition, these molecules have been implicated in aging, human immunodeficiency virus infection, drug abuse, stress, and cancer development. In this review, we will focus on the mechanisms that regulate Fas and FasL expression, and how their deregulation leads to diseases.

Mycotoxins (trichothecenes, zearalenone and fumonisins) in cereals associated with human red-mold intoxications stored since 1989 and 1991 in China

Two corn powder samples implicated in the human food poisoning that occurred in Guangxi province in 1989, and eight wheat and two barley samples linked to an episode that involved about 130,000 people in gastrointestinal disorders in Anhui province in 1991 were analyzed for trichothecenes including deoxynivalenol (DON), nivalenol (NIV) and their esters, zearalenone (ZEA) and fumonisins (FMs) by gas chromatography/mass spectroscopy and high performance liquid chromatography, and T-2 toxin by enzyme-linked immunosorbent assays. DON was detected in all samples as a major trichothecene (16-51,450 microg kg(-1)), and NIV was in one corn, one barley and all wheat at relatively low levels (10-6935 microg kg(-1)). ZEA was found in all corn and barley, and six wheat samples (46-3079 microg kg(-1)). In addition, 3-acetyl-DON (2544 microg kg(-1)) and 15-acetyl-DON (2537 microg kg(-1)) were detected separately in one corn and one wheat sample. The highest levels of these mycotoxins were found in one wheat sample associated with the human intoxication in Anhui province. FMs in corn were below 1000 microg kg(-1). Risks of DON and ZEA on the people who consumed the causative cereals were assessed.

National food contamination monitoring programmes-levels of mercury, lead and cadmium in Chinese foods

Six hundred and thirty-four food samples of six kinds were collected from Beijing, Shanghai, Jiangsu, Sichuan, Jilin and Guangdong areas, China and Hg, Pb, Cd contents were determined. The results showed that their levels in the Chinese foods were low; their levels in meat, egg, milk and fish were generally below the national hygienic standard. The average daily dietary intake of Hg, Pb, Cd were 7.25 micrograms, 103.77 micrograms and 30.72 micrograms respectively and they were all less than the ADI established by WHO.

Non-Newtonian flow patterns associated with an arterial stenosis

A non-Newtonian constitutive equation for blood has been introduced in this paper. Using this equation, blood flow attributes such as velocity profiles, flowrate, pressure gradient, and wall shear stress in both straight and stenotic (constricted) tubes have been examined. Results showed that compared with Newtonian flow at the same flowrate, the non-Newtonian normally features larger pressure gradient, higher wall shear stress, and different velocity profile, especially in stenotic tube. In addition, the non-Newtonian stenotic flow appears to be more stable than Newtonian flow.