Observation of Stark many-body localization without disorder.

Thermalization is a ubiquitous process of statistical physics, in which a physical system reaches an equilibrium state that is defined by a few global properties such as temperature. Even in isolated quantum many-body systems, limited to reversible dynamics, thermalization typically prevails1. However, in these systems, there is another possibility: many-body localization (MBL) can result in preservation of a non-thermal state2,3. While disorder has long been considered an essential ingredient for this phenomenon, recent theoretical work has suggested that a quantum many-body system with a spatially increasing field-but no disorder-can also exhibit MBL4, resulting in 'Stark MBL'5. Here we realize Stark MBL in a trapped-ion quantum simulator and demonstrate its key properties: halting of thermalization and slow propagation of correlations. Tailoring the interactions between ionic spins in an effective field gradient, we directly observe their microscopic equilibration for a variety of initial states, and we apply single-site control to measure correlations between separate regions of the spin chain. Furthermore, by engineering a varying gradient, we create a disorder-free system with coexisting long-lived thermalized and non-thermal regions. The results demonstrate the unexpected generality of MBL, with implications about the fundamental requirements for thermalization and with potential uses in engineering long-lived non-equilibrium quantum matter.

[Preparation of interleukin-1ß-targeted nanobodies and their effects on apoptosis in hypoxic cardiomyocytes of mice].

Objective: To prepare interleukin-1ß-targeted nanoantibodies and observe their effects on apoptosis in hypoxic cardiomyocyte of mice. Methods: Using DNA recombination technology, the pET-16b and pHEN1 expression vectors were used to construct the prokaryotic expression plasmids of interleukin-1ß-targeted nanobodies (pET-16b-4G6M-VHH, pET-16b-5BVP-VHH, pET-16b-5MVZ-VHH, pHEN1-4G6M-VHH, pHEN1-5BVP-VHH and pHEN1-5MVZ-VHH, where VHH is a variable domain of heavy chain antibody, 4G6M-VHH, 5BVP-VHH, 5MVZ-VHH were three interleukin-1ß-targeted nanoantibodies respectively). The constructed plasmids were transferred into Escherichia coli Rosetta2 (DE3) for induction of expression and nickel column purification, respectively. The sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and Western blotting were employed to identify the expression product and purified product, and the enzyme-linked immune sorbent assay (ELISA) was performed to determine their affinity. The cardiomyocyte hypoxia model was used with the highest affinity IL-1ß-targeted nanobody (pHEN1-5MVZ-VHH), and cell survival and apoptosis rates were detected (the experiment was divided into normal control group, hypoxia model group, blank plasmid group and 12.5, 25.0, 50.0 µg/ml pHEN1-5MVZ-VHH treatment groups). Results: SDS-PAGE and Western blotting results showed that the anti-interleukin-1ß (IL-1ß) nanobodies with a relative molecular mass of about 15 000 were successfully obtained. Likewise, ELISA results found that the nanobodies expressed in pHEN1 vector group had higher affinity for IL-1ß antigen compared with pET-16b vector group (4G6M-VHH group: 3.20±0.03 vs 1.20±0.03, P<0.001; 5BVP-VHH group: 3.18±0.06 vs 1.21±0.02, P<0.001; 5MVZ-VHH group: 3.38±0.05 vs 1.62±0.04, P<0.001). Additionally, the results of cell survival assay and apoptosis assay detected that compared with the hypoxia model group, HL-1 cell activity was significantly increased in the 25.0 µg/ml and 50.0 µg/ml pHEN1-5MVZ-VHH treatment groups [(75.55±2.23)% vs (46.90±2.51)%, P<0.001; (74.36±1.96)% vs (46.90±2.51)%, P<0.001], and apoptosis rate was significantly reduced [(6.83±0.27)% vs (10.24±0.76)%, P<0.001; (6.68±0.38)% vs (10.24±0.76)%, P<0.001]. Conclusions: 4G6M-VHH, 5BVP-VHH, and 5MVZ-VHH are expressed by both pET-16b and pHEN1 expression vectors and the nanobodies produced by the pHEN1 vector display enhanced antigen affinity. Furthermore, in hypoxic cardiomyocytes, pHEN1-5MVZ-VHH treatment reduces cell apoptosis.

[Effect of continuous blood purification for acute renal injury after acute Stanford type A aortic dissection].

Objective: To investigate the effect of continuous renal replacement therapy (CRRT) on acute kidney injury (AKI) after acute Stanford type A aortic dissection (ATTAD). Methods: In this study, 120 patients with AKI after ATTAD surgery treat in Gansu Provincial People's Hospital were selected as research objects. Among them, there were 86 males (71.7%) and 34 females (28.3%) with a mean age of (55±5) years. These patients were randomly divided into experimental group (n=60) and control group (n=60) with stratified random sampling. CRRT and intermittent hemodialysis (IHD) were performed in the experimental group and the control group respectively. The therapeutic effect of CRRT on ATTAD patients with AKI was evaluated by blood purification index, renal function index, Sequential Organ Failure Assessment (SOFA) score, inflammatory level, hemodynamic index and fluid infusion volume. Results: The two treatment schemes both had considerable therapeutic effects on the condition of patients, but the therapeutic effect of CRRT was more superior. In the patients treated with CRRT, the levels of serium creatinine (SCr), blood urea nitrogen (BUN) and blood lactic acid (Lac) were all lower than those in the control group (all P<0.05). The time of staying in intensive care units (ICU), the period of oliguria, the times of renal replacement therapy, the time from the first dialysis to the last dialysis and the total hospital stay in the experimental group were all shorter than those in the control group (all P<0.05). The volume of fluid infusion was less and the hemodynamic index was better than that in the control group, but there was no significant difference in hospital mortality between the two groups (P>0.05). The levels of interleukin (IL)-6, IL-8 and C-reactive protein (CRP) in the experimental group were (21.9±1.8) ng/L, (18.6±1.4) ng/L and (22.7±2.2) mg/L, respectively, which were all significantly lower than those in control group ((27.9±3.2) ng/L, (28.3±1.4) ng/L, (60.1±2.5)mg/L, respectively; t=14.527, 13.255, 11.247, all P<0.05). The scores of SOFA at all time points in the experimental group were all lower than those in the control group (all P<0.05). Conclusion: Compared with IHD, CRRT brings no significant reduction in hospital mortality in patients with AKI after ATTAD, but shows better prognosis.

[Meta-analysis of annual probability of outcome for different cervical disease states].

Objective: To explore the annual probabilities of outcomes for different cervical disease states. Methods: Cohort studies related to the natural history of cervical cancer were retrieved from PubMed, Embase and China Biomedical Literature Database, and the retrieval time was from the establishment of the database to May 2020. Newcastle-Ottawa scale was used to evaluate the quality of the included literatures. The annual outcome probabilities of different cervical disease states in high-risk human papillomavirus (hrHPV) positive, negative and cervical intraepithelial neoplasia grade 1 (CIN1) population were calculated (95%CI). Random-effects model was used for meta-analysis. Egger's test was used to evaluate publication bias; sensitivity analysis was used to evaluate the robustness of the combined parameters. Meta-regression was used to explore factors associated with the heterogeneity of annual outcome probability. Results: A total of 37 studies were included, including 12, 20 and 15 studies involving hrHPV negative, hrHPV positive and CIN1 population, respectively, with a Newcastle -Ottawa scale (NOS) score of 7.05±1.20. The annual probability (95%CI) of progression to CIN1, CIN2 and CIN3+ in hrHPV-positive population were 0.022 2 (0.014 3, 0.031 0), 0.017 0 (0.012 0, 0.022 0) and 0.016 2 (0.012 6, 0.019 8), respectively. The annual probability (95%CI) of progression to CIN1, CIN2 and CIN3+ in hrHPV-negative population was 0.002 7 (0.000 9, 0.004 6), 0.000 7 (0.000 3, 0.001 1) and 0.000 6 (0.000 3, 0.000 9), respectively. The annual probability (95%CI) of reversal to normal, maintenance of CIN1 status and progression to cervical intraepithelial neoplasia grade 2 or above (CIN2+) in CIN1 population were 0.578 1 (0.369 9, 0.786 3), 0.400 1 (0.167 4, 0.632 9), 0.056 9 (0.034 9, 0.078 9), respectively. Egger's test showed that there was publication bias in the annual outcome probability of hrHPV positive progression to CIN2 and CIN3+ and hrHPV negative progression to CIN2 and CIN1 progression to CIN2+, with t values of 5.50, 2.36, 2.80 and 4.12, respectively (all P values<0.05). Sensitivity analysis showed that when excluding any of the studies, the range of annual probability of progression to CIN1, CIN2 and CIN3+ were 0.016 6-0.024 7, 0.014 9-0.018 9 and 0.013 6-0.017 7 among hrHPV-positive population; 0.002 4-0.003 5, 0.000 6-0.000 9 and 0.000 5-0.000 7 among hrHPV-negative population and the range of annual probability of CIN1 reversal to normal, maintenance as CIN1 and progression to CIN2+ were 0.531 8-0.631 2, 0.321 9-0.443 3, and 0.052 0-0.061 0, respectively. Meta-regression analysis showed that region, population origin, population cytological diagnosis, follow-up time, and NOS score were not associated with the heterogeneity of annual outcome probability (all P values>0.05). Conclusion: The annual outcome probability of different cervical disease states in hrHPV positive population is high, and the CIN1 population only needs close follow-up.

[Global development of human papillomavirus vaccination guidelines: a systematic review].

Objective: To systematically summarize the development of global human papillomavirus (HPV) vaccination guidelines. Methods: The retrieval for all the Chinese and English literature published before August 2020 was conducted in PubMed, Embase and China Biomedical Literature Database, with "papillomavirus vaccines" "wart virus vaccine" "guideline" "practice guideline" "health planning guidelines" "guidelines as topic" "practice guidelines as topic" "immunization programs" in English as well as "papillomavirus vaccines" "HPV vaccine" "guideline" "recommendation" "consensus" in Chinese as search keywords. A total of 18 guidelines were included for data extraction and analysis. Results: The 18 pieces of guidelines included 1 pieces of World Health Organization (WHO) position paper, 6 pieces of guidelines at national or provincial level and other 11 pieces of by academic institutions. In national or provincial guidelines, the recommendation for routine vaccination mainly focused on 11-13 year-old adolescents and the recommendation for catch-up vaccination extends to 17-26 years old. Recommendation of guidelines by academic institutions were similar to the WHO position paper: girls aged 9-14 as the primary target for the routine vaccination; females aged 15-26 years old as the secondary target populations when it's feasible, affordable and cost-effective; women aged over 26 could be vaccinated at an individual level. There were only three guidelines simultaneously updated with the national immunization programme and covered four aspects: the vaccinated population (girls-only to gender-neutral vaccination), the periodic catch-up immunization, the dose schedule updates and the change of vaccine types. Conclusions: It's recommended that the development of Chinese HPV vaccination guidelines refer to global guidelines and updates and take full consideration of the epidemiological evidence, resources and current status of the immunization system in China.

Clinical and molecular insights into Glanzmann's thrombasthenia in China.

Glanzmann's thrombasthenia (GT) is a rare bleeding disorder characterized by spontaneous mucocutaneous bleeding. The disorder is caused by quantitative or qualitative defects in integrin αIIbß3 (encoded by ITGA2B and ITGB3) on the platelet and is more common in consanguineous populations. However, the prevalence rate and clinical characteristics of GT in non-consanguineous populations have been unclear. We analyzed 97 patients from 93 families with GT in the Han population in China. This analysis showed lower consanguinity (18.3%) in Han patients than other ethnic populations in GT-prone countries. Compared with other ethnic populations, there was no significant difference in the distribution of GT types. Han females suffered more severe bleeding and had a poorer prognosis. We identified a total of 43 different ITGA2B and ITGB3 variants, including 25 previously unidentified, in 45 patients. These variants included 14 missense, 4 nonsense, 4 frameshift, and 3 splicing site variants. Patients with the same genotype generally manifested the same GT type but presented with different bleeding severities. This suggests that GT clinical phenotype does not solely depend on genotype. Our study provides an initial, yet important, clinical and molecular characterization of GT heterogeneity in China.

A mathematical model of antibody-dependent cellular cytotoxicity (ADCC).

Immunotherapies exploit the immune system to target and kill cancer cells, while sparing healthy tissue. Antibody therapies, an important class of immunotherapies, involve the binding to specific antigens on the surface of the tumour cells of antibodies that activate natural killer (NK) cells to kill the tumour cells. Preclinical assessment of molecules that may cause antibody-dependent cellular cytotoxicity (ADCC) involves co-culturing cancer cells, NK cells and antibody in vitro for several hours and measuring subsequent levels of tumour cell lysis. Here we develop a mathematical model of such an in vitro ADCC assay, formulated as a system of time-dependent ordinary differential equations and in which NK cells kill cancer cells at a rate which depends on the amount of antibody bound to each cancer cell. Numerical simulations generated using experimentally-based parameter estimates reveal that the system evolves on two timescales: a fast timescale on which antibodies bind to receptors on the surface of the tumour cells, and NK cells form complexes with the cancer cells, and a longer time-scale on which the NK cells kill the cancer cells. We construct approximate model solutions on each timescale, and show that they are in good agreement with numerical simulations of the full system. Our results show how the processes involved in ADCC change as the initial concentration of antibody and NK-cancer cell ratio are varied. We use these results to explain what information about the tumour cell kill rate can be extracted from the cytotoxicity assays.

[Correlation between morphogical factor of lateral plateau fracture and meniscus injury].

OBJECTIVE: To analyze morphological character of lateral tibial plateau fracture fragment, and its correlation to the presence of a meniscus injury in tibial plateau fractures. METHODS: A total of 79 consecutive patients of the simple lateral tibial plateau fractures from July 2011 to July 2015 were included in this study, with 65 males and 14 females with an average age of (34.3±7.2) years and 22-61 years. According to Schatzker classification, 21 cases were of Type I, 41 cases Type II, and 17 cases Type III. The characteristics of lateral tibial plateau fractures were evaluated by plain X-ray and magnetic resonance imaging (MRI). The type and severity of meniscus injury were diagnosed by MRI scan. Three-dimensional measurements of the lateral fragment width (LFW), the lateral plateau depression (LPD), the coronal angulation of lateral fragment (CALF), and tibial plateau widening (TPW) were measured with Picture Archiving and Communication Systems(PACS) software. The patients with and without meniscus injuries were divided into different groups and analyzed respectively. Comparison of the above measurements between the two groups was analyzed by independent t test. RESULTS: In all the 79 lateral tibial plateau fracture patients, 26 cases (32.9%) of meniscus injuries were detected by MRI. Among all the meniscus injury cases, 3 were of Schatzker I, 16 Schatzker II, and 7 Schatzker III. In meniscus intact group, the average LFW was (22.0±2.8) mm while in meniscus injury group it was (21.3± 3.3) mm (t=-1.008, P=0.317).The average LPD of non meniscus injury group was (5.4±2.8) mm, while in meniscus injury group was (8.7±2.8) mm (t=4.98, P=0.001). The average CALF of the two groups were 9.1°±6.1°and 10.6°± 7.1°, and there was no significant difference between the two groups (t=0.38, P=0.831). The average TPW was (3.0± 1.1) mm, and (4.8±1.7) mm of the two groups. There were significant differences between the two groups (t=5.216, P=0.001). CONCLUSION: There was no obvious correlation between the LFD and meniscus injury. The CALF of lateral tibial plateau fracture had no significant correlation with meniscus injury either. The degree of LPD and TPW may indicate injury of the meniscus in tibial plateau fractures.

[Causes and countermeasures of the rapidly rising burden on cervical cancer in Chinese women].

The world is entering a new era of accelerated elimination of cervical cancer, while the age-standardized incidence, and mortality of cervical cancer in China are rising rapidly. This article summarizes and describes the current situation and trends of the burden of cervical cancer in China, reviews and analyzes the comprehensive prevention practice of cervical cancer, focusing on critical reasons for the increasing burden of cervical cancer, from the perspectives of sociology, behavior, and epidemiology in the population. Countermeasures are proposed to provide guidance and theoretical reference for the precise prevention of cervical cancer to eliminate cervical cancer.

[Prognostic analysis and predictive model construction of bleeding events in allogeneic hematopoietic stem cell transplant patients].

Objective: To study hematopoietic stem cell transplantation-related bleeding prognosis and construct a bleeding prediction model. Methods: The clinical data of 555 patients with malignant hematologic diseases who underwent allogeneic hematopoietic stem cell transplantation between May 1(st) 2004, and April 1(st) 2012 was analyzed retrospectively, and a prediction model was constructed. Results: Of the 555 patients, a total of 302 (54.0% ) patients exhibited bleeding events of varying degrees, including 151 (27.0% ) with grade Ⅰ bleeding, 63 (11.0% ) with grade Ⅱ bleeding, 48 (9.0% ) with grade Ⅲ bleeding, and 40 (7.0% ) with grade Ⅳ bleeding. Multifactorial analysis showed that the overall mortality (HR=12.53, 95% CI 7.91-19.87, P<0.001) and non-recurrence mortality (HR=23.79, 95% CI 12.23-46.26, P<0.001) were higher in patients with higher bleeding grades (Ⅲ and Ⅳ bleeding) compared to those with lower bleeding grades. Additionally, the donor's underlying disease, graft-versus-host disease (GVHD) score, poor platelet reconstitution, and ineffective platelet transfusion were independently associated with bleeding risk. The bleeding model constructed using the above variables showed good accuracy (C-Index=0.934) , and its efficacy was significantly higher than previous bleeding models. Conclusion: Hematopoietic stem cell transplant patients are at increased risk of death after a bleeding event. The cross-validated bleeding risk prediction model is valuable for early intervention.

MiR-21 regulates pulmonary hypertension in rats via TGF-ß1/Smad2 signaling pathway.

The article "MiR-21 regulates pulmonary hypertension in rats via TGF-ß1/Smad2 signaling pathway, by F. Ding, T. You, X.-D. Hou, K. Yi, X.-G. Liu, P. Zhang, X.-K. Wang, published in Eur Rev Med Pharmacol Sci 2019; 23 (9): 3984-3992-DOI: 10.26355/eurrev_201905_17828-PMID: 31115027" has been withdrawn from the authors. The Publisher apologizes for any inconvenience this may cause. https://www.europeanreview.org/article/17828.

Myocardial Infarction Detection Based on Multi-lead Ensemble Neural Network.

Automatic myocardial infarction (MI) detection using an electrocardiogram (ECG) is of great significance for improving the survival rate of patients. In this study, we propose a multi-lead ensemble neural network (MENN) to distinguish anterior myocardial infarction (AMI) and inferior myocardial infarction (IMI) from healthy control (HC) respectively. In the study, three kinds of sub-networks and multi-lead ECG signals are combined, which fully explores the information of ECG signals and improves the classification performance. The algorithm is evaluated on the PTB database by 5-fold inter-subject cross-validation and the sensitivity (Se), specificity (Sp) and area under the curve (AUC) of AMI detection are 98.35%, 97.49%, 97.92%; The Se, Sp, and AUC of IMI detection are 93.17%, 92.02%, 92.60%. The proposed method achieves the state of the art results on both tasks and outperforms the baseline methods. Hence, the proposed method is potential for automatic MI diagnosis.

MiR-21 regulates pulmonary hypertension in rats via TGF-ß1/Smad2 signaling pathway.

OBJECTIVE: To investigate the effects of micro ribonucleic acid (miR)-21 on pulmonary hypertension (PH) in rats via regulating tumor growth factor-ß1 (TGF-ß1)/mothers against decapentaplegic homolog 2 (Smad2) signaling pathway and the possible underlying mechanism. MATERIALS AND METHODS: MiR-21 inhibition vector (pLKO-anti-miR-21) was first constructed. The rat model of PH was established by hypoxia feeding induction. A total of three groups were established, including: blank control group, model group and miR-21 low-expression group were set up, with 12 rats in each group. The expression level of miR-21 in lung tissues of rats in each group was detected via quantitative polymerase chain reaction (qPCR). The right ventricle systolic pressure (RVSP) and right ventricular hypertrophy index (RVHI) of rats in each group were measured. The pathological changes in lung tissues of rats were detected using hematoxylin and eosin (H&E) staining. Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining was used to detect the level of apoptosis in lung tissues of rats in each group. Furthermore, Western blotting was adopted to detect the expression levels of TGF-ß1/Smad2 signal pathway-related proteins and apoptosis-related proteins in lung tissues of rats in each group. RESULTS: Compared with blank control group, the expression level of miR-21 in lung tissues of rats in model group was significantly increased (p<0.01). Meanwhile, miR-21 expression in lung tissues of rats in miR-21 low-expression group was significantly decreased by transfection of miR-21 inhibition vector (p<0.01). The RVSP and RVHI of rats in model group were significantly higher than those of blank control group and miR-21 low-expression group (p<0.01). H&E staining results indicated that the degree of lung tissue injury in model group was remarkably higher than blank control group and miR-21 low-expression group (p<0.01). According to TUNEL staining results, the number of apoptotic cells in lung tissues of rats in model group was markedly smaller than that of miR-21 low-expression group (p<0.01). Moreover, the expression level of Caspase 3 in lung tissues of rats in model group was significantly lower than that of miR-21 low-expression group, while the expression level of B-cell lymphoma 2 (Bcl-2)/Bcl-2-associated X protein (BAX) was markedly higher. The expression levels of TGF-ß1 and phosphorylated (p)-Smad2 in lung tissues of rats in model group were evidently higher than those of blank control group (p<0.01). In addition, lowly expressed miR-21 could effectively reduce the expressions of TGF-ß1 and p-Smad2 (p<0.01). CONCLUSIONS: MiR-21 regulates the symptoms of PH in rats by activating TGF-ß1/Smad2 signaling pathway.

Concomitant mitral valve replacement and tricuspid valvuloplasty for severe mitral stenosis.

OBJECTIVE: The purpose of this work is to analyze the clinical results of treating severe mitral stenosis (MS) with mild to moderate functional tricuspid regurgitation (FTR) with mitral valve replacement (MVR) alone or together with two different methods of tricuspid valvuloplasty (TVP). PATIENTS AND METHODS: We split 132 patients into three groups: simple MVR with 47 cases (control group), MVR+ TVP (De Vega loop reduction) with 45 cases (observation group 1) and MVR+ TVP (Edwards MC3 tricuspid forming ring implantation) with 40 cases (observation group 2). RESULTS: As expected, surgery for both observation groups was longer than for the control group, but we found no differences in aortic clamping time, cardiopulmonary bypass time, perioperative complications, and postoperative hospital stay. We found significantly fewer complications in both observation groups compared to the control group. After surgery, the diameter of the tricuspid valve ring and the maximum reflux bundle were significantly lower in the observation groups compared to the control group. CONCLUSIONS: Overall, the long-term clinical effect of combined MVR and TVP to treat severe MS with mild to moderate FTR is better than using the simple MVR procedure. Our results also suggest that the Edwards MC3 tricuspid forming ring implantation is superior to the De Vega loop reduction.

Respiratory signal prediction based on adaptive boosting and multi-layer perceptron neural network.

To improve the prediction accuracy of respiratory signals using adaptive boosting and multi-layer perceptron neural network (ADMLP-NN) for gated treatment of moving target in radiation therapy. The respiratory signals acquired using a real-time position management (RPM) device from 138 previous 4DCT scans were retrospectively used in this study. The ADMLP-NN was composed of several artificial neural networks (ANNs) which were used as weaker predictors to compose a stronger predictor. The respiratory signal was initially smoothed using a Savitzky-Golay finite impulse response smoothing filter (S-G filter). Then, several similar multi-layer perceptron neural networks (MLP-NNs) were configured to estimate future respiratory signal position from its previous positions. Finally, an adaptive boosting (Adaboost) decision algorithm was used to set weights for each MLP-NN based on the sample prediction error of each MLP-NN. Two prediction methods, MLP-NN and ADMLP-NN (MLP-NN plus adaptive boosting), were evaluated by calculating correlation coefficient and root-mean-square-error between true and predicted signals. For predicting 500 ms ahead of prediction, average correlation coefficients were improved from 0.83 (MLP-NN method) to 0.89 (ADMLP-NN method). The average of root-mean-square-error (relative unit) for 500 ms ahead of prediction using ADMLP-NN were reduced by 27.9%, compared to those using MLP-NN. The preliminary results demonstrate that the ADMLP-NN respiratory prediction method is more accurate than the MLP-NN method and can improve the respiration prediction accuracy.

Mutations at the arginine residues in alpha8 loop of Bacillus thuringiensis delta-endotoxin Cry1Ac affect toxicity and binding to Manduca sexta and Lymantria dispar aminopeptidase N.

The functional role of the alpha8 loop residues in domain II of Bacillus thuringiensis Cry1Ac toxin was examined. Alanine substitution mutations were introduced in the residues from 275 to 293. Among the mutant toxins, substitutions at R281 and R289 affected toxicity to Manduca sexta and Lymantria dispar. Loss of toxicity by these mutant toxins was well correlated with reductions in binding affinity for brush border membrane vesicles and the purified receptor, aminopeptidase N (APN), from both insects. These data suggest that the two arginine residues in the alpha8 loop region are important in toxicity and APN binding in L. dispar and M. sexta.

Transscleral delivery of bioactive protein to the choroid and retina.

PURPOSE: To investigate the feasibility of transscleral drug delivery to the choroid and retina. METHODS: An osmotic pump was used to deliver IgG across the sclera of pigmented rabbits, and levels were measured in the choroid, retina, vitreous humor, aqueous humor, orbit, and plasma over 28 days. This method was then used to deliver an anti-intercellular adhesion molecule-1 (ICAM-1) monoclonal antibody (mAb), and its effect on inhibiting vascular endothelial growth factor (VEGF)-induced leukostasis in the choroid and retina was determined by measuring tissue myeloperoxidase (MPO) activity. RESULTS: Levels of retinal and choroidal IgG were significantly higher than baseline at all points up to 28 days (P < or = 0.01). IgG levels in the orbit, vitreous humor, aqueous humor, and plasma were negligible (P > 0.05). MPO activity in the choroid of eyes treated with anti-ICAM-1 mAb was 80% less (P = 0.01) than in eyes receiving an equal rate of delivery of an isotype control antibody. Inhibition of MPO activity in the retina was 70% (P = 0.01). The plasma concentration of anti-ICAM-1 mAb was 31,000-fold less than the concentration in the osmotic pump. CONCLUSIONS: Minimally invasive transscleral delivery can be used to deliver therapeutic levels of bioactive drugs to the choroid and retina with negligible systemic absorption. This method of ocular drug delivery may be used in the treatment of a variety of chorioretinal disorders.

High performance liquid chromatographic determination of free and conjugated bile acids in serum, liver biopsies, bile, gastric juice and feces by fluorescence labeling.

Separation and measurement of commonly occurring free and conjugated bile acids in serum, liver biopsies, bile, gastric juice and feces have been successfully accomplished using high performance liquid chromatography with fluorescence labeling. Free and conjugated bile acids were extracted from pretreated samples using Sep-Pak C18 cartridges and then fractionated on a piperidinohydroxypropyl Sephadex LH-20 column. Free and glycine conjugated bile acids were labelled with 4-bromomethyl-7-methoxycoumarin. Taurine conjugated bile acids were hydrolysed with cholylglycine hydrolase prior to derivatization with 4-bromomethyl-7-methoxycoumarin. Labelled bile acids were eluted using an acetonitrile/methanol/water gradient on an ultrasphere ODS column. The eluate was monitored by a fluorophotometer at 360 nm (excitation) and 410 nm (emission). Linearity was obtained between 50 and 400 nmol. Recoveries from serum, gastric juice and feces were greater than 87%. This is therefore a sensitive method for the precise quantification of bile acids in serum, liver biopsies, bile, gastric juice and feces.

Combination of amperometric detector & UV detector for capillary electrophoresis.

A new electrochemical cell assembly with the combination of UV and amperometric detector (AD) based on their complementarity was described. A Nafion tubing junction was used to decouple the high voltage from the separation capillary in the rear of on-column UV detector. In this mode, the electroactive and inert compounds could be detected by UV and AD at the same time. Aromatic amines were determined with the UV and the end-column AD detection to evaluate the performances of the cell assembly. Such an improved electrochemical detector could match the capillary with different diameters. By simple adjustment of the screws, the positioning of the working electrode and the detection capillary was easily gained without microscope. It is also very easy to assemble and disassemble the working electrode when needed.