[Study on the comparison of postoperative liver injury caused by hepatic arterial perfusion chemotherapy combined with targeted immunotherapy with hepatic arterial chemoembolization combined with targeted immunotherapy for intermediate-and advanced-stage liver cancer]

Objective: To compare the postoperative liver function injury condition in patients with intermediate-and advanced-stage hepatocellular carcinoma (HCC) treated with hepatic artery infusion chemotherapy (HAIC) and hepatic artery chemoembolization (TACE) combined with immune checkpoint inhibitors (ICIs) and multi-target tyrosine kinase inhibitors (TKIs). Methods: Patients with intermediate-and advanced-stage HCC who were admitted and treated with HAIC/TACE+ICIs+TKIs therapy at Nanfang Hospital of Southern Medical University from January 2019 to November 2021, with follow-up up to July 2023, were retrospectively enrolled. The results of liver function tests within one week before interventional surgery and on the first day after surgery were recorded. The degree of postoperative liver injury was graded according to the common terminology criteria for adverse events 5.0 (CTCAE 5.0). The treatment efficacy was evaluated according to RECIST 1.1 criteria. Measurement data were compared between groups using a t-test or a non-parametric rank sum test. Enumeration data were compared between the groups using the χ(2) test or Fisher's exact probability method. The survival condition differences were analyzed by the log-rank method. Results: This study included 82 and 77 cases in the HAIC and TACE groups. There were no statistically significant differences between the two groups of patients in terms of gender, age, physical condition score, number of tumors, presence or absence of liver cirrhosis, Child-Pugh grade, albumin-bilirubin (ALBI) grade, and combined ICIs and TKIs . The HAIC group had later tumor staging, a greater tumor burden, poorer liver reserve function, and a larger proportion of patients in stage C (81.7% vs. 63.6%), χ(2)=6.573, P = 0.01). There were 53 cases (64.6% vs. 32.5%) with a maximum tumor diameter of ≥ 10cm, χ(2)=16.441, P < 0.001), and more patients had a retention rate of ≥ 10% for indocyanine green (ICG) at 15 minutes (68.3% vs. 51.9%, P = 0.035). The postoperative incidence rate of increased levels of alanine aminotransferase, aspartate aminotransferase, and total bilirubin was significantly lower in the HAIC group than that in the TACE group (28.0% vs. 63.6%, χ(2)=20.298, P < 0.001, 54.9% vs. 85.7%, χ(2)=17.917, P < 0.001;40.2% vs. 55.8%, χ(2)=3.873, P = 0.049). The number of patients with postoperative ALBI grade 3 was significantly lower in the HAIC group than that in the TACE group (6.1% vs. 16.9%, χ(2)=4.601, P = 0.032). There was no statistically significant difference in the incidence rate of postoperative hypoalbuminemia, activated partial thromboplastin time, or increased international standardized ratio between the two groups of patients. There was no statistically significant difference in median progression-free survival (7.3 months vs. 8.2 months, P = 0.296) or median overall survival (16.5 months vs. 21.9 months, P = 0.678) between the two groups of patients. Conclusion: The incidence rate of postoperative liver injury is higher in patients with intermediate-and advanced-stage HCC treated with TACE combined with ICIs and TKIs than in patients with HAIC combined with ICIs and TKIs.

[Predictive value of aMAP risk score for early recurrence of small hepatocellular carcinoma after microwave ablation]

Objective: To explore the value of the aMAP risk score (age, male, albumin-bilirubin, and platelets) to predict early recurrence within one year after microwave ablation in patients with small hepatocellular carcinoma. Methods: This was a retrospective study that enrolled 142 patients diagnosed with hepatocellular carcinoma who were treated with microwave ablation in the Department of Hepatology Unit of Nanfang Hospital, Southern Medical University from July 2016 to July 2021. The cohort enrolled 121 male and 21 female patients, including 110 patients that were <60 years old. All the patients were followed-up after microwave ablation to evaluate residual tumor and recurrence of tumor by computed tomography or magnetic resonance imaging. The observation indices mainly included general data and imaging data of patients. Using the X-tile tools, patients were divided into two groups: a high aMAP score group and a low aMAP score group. Multivariate Cox regression analysis was conducted for comparison of independent risk factors. Results: Multivariate Cox regression showed that high aMAP score, maximum tumor diameter >20 mm, and high AFP were the independent risk factors of early recurrence (all P<0.05). Kaplan-Meier survival curves showed that the median recurrence-free survival was 25.5 months in the low aMAP score group and 6.1 months in the high aMAP score group (P=0.001). Conclusions: The aMAP score could predict the early recurrence within 1 year of small hepatocellular carcinoma after microwave ablation. Patients with high aMAP score should undergo rigorous postoperative follow-up evaluations..

Binding modes of GDP, GTP and GNP to NRAS deciphered by using Gaussian accelerated molecular dynamics simulations

Probing binding modes of GDP, GTP and GNP to NRAS are of significance for understanding the regulation mechanism on the activity of RAS proteins. Four separate Gaussian accelerated molecular dynamics (GaMD) simulations were performed on the apo, GDP-, GTP- and GNP-bound NRAS. Dynamics analyses suggest that binding of three ligands highly affects conformational states of the switch domains from NRAS, which disturbs binding of NRAS to its effectors. The analyses of free energy landscapes (FELs) indicate that binding of GDP, GTP and GNP induces more energetic states of NRAS compared to the apo NRAS but the presence of GNP makes the switch domains more ordered than binding of GDP and GNP. The information of interaction networks of ligands with NRAS reveals that the π-π interaction of residue F28 and the salt bridge interactions of K16 and D119 with ligands stabilize binding of GDP, GTP and GNP to NRAS. Meanwhile magnesium ion plays a bridge role in interactions of ligands with NRAS, which is favourable for associations of GDP, GTP and GNP with NRAS. This work is expected to provide useful information for deeply understanding the function and activity of NRAS.

Localization of CgVPE1 in secondary cell wall formation during tracheary element differentiation in the pericarp of Citrus grandis 'Tomentosa' fruits

CgVPE1 is important in the differentiation of TE cells in C. grandis 'Tomentosa' fruits as it may directly affects secondary cell wall construction while participating in PCD. The vacuolar processing enzyme (VPE) plays an important role in both developmental and environmentally inducible programmed cell death (PCD); it was originally identified as a cysteine protease localized in the vacuole to activate and mature vacuolar proteins in plants. Interestingly, we found a VPE called CgVPE1 to be associated with deposition of the secondary cell wall in tracheary element (TE) cells in the pericarp of Citrus grandis 'Tomentosa' fruits. We then used ultrathin sections and the TUNEL assay to verify that PCD is involved in TE development. Furthermore, CgVPE1 was found to be mainly expressed in secretory cavities and TEs in the pericarp of Citrus grandis 'Tomentosa' fruits. Immunolocalization of CgVPE1 in the pericarp indicated that CgVPE1 is mainly distributed in the central large vacuole, endoplasmic reticulum, Golgi vesicles, cytosol, and secondary wall before TE maturation. CgVPE1 appeared earlier in the endoplasmic reticulum and Golgi vesicles of TEs cells. The vesicles containing CgVPE1 near the large central vacuole and secondary wall were observed, respectively. CgVPE1 proteins content in the cytoplasm decreased sharply, while the CgVPE1 content in the secondary cell wall did not change significantly after vacuole rupture. CgVPE1 protein contents in the secondary cell wall were significantly reduced until the TE cells developed into hollow thick-walled cells. Furthermore, labeling of VPE homologues in Arabidopsis thaliana using immunoelectron microscopy with anti-CgVPE1 antibody revealed that VPE homologues were specifically distributed in the secondary cell wall of stem TEs. Overall, these results suggested that CgVPE1 is not only involved PCD during TE cell development; furthermore, it may directly participate in the construction of plant secondary cell walls.

Intranasal delivery of a synthetic Entamoeba histolytica vaccine containing adjuvant (LecA + GLA-3M-052 liposomes): in vitro characterization

Amebiasis, a disease caused by the parasite Entamoeba histolytica, is estimated to cause millions of infections and at least 55,000 deaths globally each year. With no vaccine currently available, there is an urgent need for an accessible means of stimulating protective mucosal immunity. The objective of this study was to characterize the nasal spray of a novel amebiasis vaccine candidate from a syringe-based liquid atomization device, the Teleflex MAD Nasal™, in both adult and infant nasal airways. Human ergonomic testing was completed to determine realistic actuation parameters. Spray pattern, plume geometry, and droplet size distribution were measured to evaluate reproducibility of free plume characteristics. The Alberta Idealized Nasal Inlet (AINI) and three realistic infant nasal airways were used to determine the in vitro deposition profile in adult and infant airways, respectively. Collectively, in vitro results demonstrated the feasibility of delivering the vaccine candidate to target sites within the nasal airways. Penetration through the nasal airways that could lead to deposition in the lungs was below the limit of quantification for both adult and infant geometries, indicating a low likelihood of adverse events due to lung exposure. These results support continued investigation of intranasal delivery of the synthetic Entamoeba histolytica vaccine.

In Vitro Evaluation of a Nasal Interface Used to Improve Delivery from a Portable Oxygen Concentrator

Portable oxygen concentrators (POCs) are widely used to administer long-term oxygen therapy (LTOT) and employ pulsed delivery modes to conserve oxygen. Efficient pulsed delivery requires that POCs are triggered by patient inhalation. Triggering is known to fail for some patients during periods of quite breathing, as occurs during sleep. The present article describes a new nasal interface designed to improve triggering of pulsed oxygen delivery from portable oxygen concentrators (POCs). In vitro experiments incorporating realistic nasal airway replicas and simulated breathing were conducted. The pressure monitored via oxygen supply tubing (the signal pressure) was measured over a range of constant inhalation flow rates with the nasal interface inserted into the nares of the nasal airway replicas, and compared with signal pressures measured for standard and flared nasal cannulas. Triggering efficiency and the fraction of inhaled oxygen (FiO2) were then evaluated for the nasal interface and cannulas used with a commercial POC during simulated tidal breathing through the replicas. Higher signal pressures were achieved for the nasal interface than for nasal cannulas at all flow rates studied. The nasal interface triggered pulsed delivery from the POC in cases where nasal cannulas failed to trigger. FiO2 was significantly higher for successful triggering cases than for failed triggering cases. The nasal interface improved triggering of pulsed oxygen delivery from a POC and presents a simple solution that could be used with commercially-available POCs to reliably supply oxygen during periods of quiet breathing.

[Analysis of the effect of microwave ablation in the treatment of small liver cancer]

Objective: To explore the clinical effect of microwave ablation in the treatment of early small liver cancer (≤3 cm). Methods: 103 cases with small liver cancer (tumor number < 3 and maximum tumor diameter < 3 cm) who underwent microwave ablation from November 2016 to November 2018 were retrospectively collected. The rate of residual lesions, recurrence rate one-year after the operation, and surgical complications were observed and grouped according to tumor size (< 2 cm and≥2 cm group) and tumor numbers (solitary and 2 ~ 3 lesion groups). The therapeutic effects of each group were compared and analyzed. Results: The tumor residual rate and one-year recurrence rate of small liver cancer after microwave ablation were 11.7% and 35.0%, respectively. The post-ablation syndrome incidence rate was 52.4%, with no serious adverse events. Compared with tumors < 2 cm, patients with≥2 cm had a higher postoperative residual rate (χ(2) = 7.651, P = 0.006), and the one-year recurrence rate of more solitary nodular tumors was lower (χ(2) = 10.125, P = 0.001). Conclusion: Microwave ablation is a safe and effective treatment for early small liver cancer, and it is more effective for small solitary nodules (< 2 cm).

[Regulatory effect of molecular targeted drugs on the immune system for liver cancer]

Molecular targeted drugs are the first choice for systemic treatment of liver cancer. In the past decade, several anti-liver cancer targeted drugs have been launched. More recently, immunotherapy has become a dazzling nova in the field of systemic treatment of liver cancer. Nivolumab and pembrolizumab have been approved as second-line treatments for patients with advanced hepatocellular carcinoma treated with sorafenib. However, the effect of single-agent treatment is always unsatisfactory in advanced liver cancer. An increasing number of evidences suggests that molecular targeted drugs have important immunomodulatory effects for liver cancer, and several targeted combined immunotherapies have also shown promising clinical effectiveness. This paper reviews the immunomodulatory effects of several molecular targeted drugs in the field of liver cancer.

[Incidence and risk factors of anastomotic leak after transanal total mesorectal excision in China: a retrospective analysis based on national database]

Objective: Transanal total mesorectal excision (taTME) was a very hot topic in the first few years since its appearance, but now more introspections and controversies on this procedure have emerged. One of the reasons why the Norwegian Ministry of Health stopped taTME was the high incidence of postoperative anastomotic leak. In current study, the incidence and risk factors of anastomotic leak after taTME were analyzed based on the data registered in the Chinese taTME Registry Collaborative (CTRC). Methods: A case-control study was carried out. Between November 15, 2017 and December 31, 2020, clinical data of 1668 patients undergoing taTME procedure registered in the CTRC database from 43 domestic centers were collected retrospectively. After excluding 98 cases without anastomosis and 109 cases without complete postoperative complication data, 1461 patients were finally enrolled for analysis. There were 1036 males (70.9%) and 425 females (29.1%) with mean age of (58.2±15.6) years and mean body mass index of (23.6±3.8) kg/m(2). Anastomotic leak was diagnosed and classified according to the International Study Group of Rectal Cancer (ISREC) criteria. The risk factors associated with postoperative anastomotic leak cases were analyzed. The impact of the cumulative number of taTME surgeries in a single center on the incidence of anastomotic leak was evaluated. As for those centers with the number of taTME surgery ≥ 40 cases, incidence of anastomic leak between 20 cases of taTME surgery in the early and later phases was compared. Results: Of 1461 patients undergoing taTME, 103(7.0%) developed anastomotic leak, including 71 (68.9%) males and 32 (31.1%) females with mean age of (59.0±13.9) years and mean body mass index of (24.5±5.7) kg/m(2). The mean distance between anastomosis site and anal verge was (2.6±1.4) cm. Thirty-nine cases (37.9%) were classified as ISREC grade A, 30 cases (29.1%) as grade B and 34 cases (33.0%) as grade C. Anastomotic leak occurred in 89 cases (7.0%,89/1263) in the laparoscopic taTME group and 14 cases (7.1%, 14/198) in the pure taTME group. Multivariate analysis showed that hand-sewn anastomosis (P=0.004) and the absence of defunctioning stoma (P=0.013) were independently associated with anastomotic leak after taTME. In the 16 centers (37.2%) which performed ≥ 30 taTME surgeries with cumulative number of 1317 taTME surgeries, 86 cases developed anastomotic leak (6.5%, 86/1317). And in the 27 centers which performed less than 30 taTME surgeries with cumulative number of 144 taTME surgeries, 17 cases developed anastomotic leak (11.8%, 17/144). There was significant difference between two kinds of center (χ(2)=5.513, P=0.019). Thirteen centers performed ≥ 40 taTME surgeries. In the early phase (the first 20 cases in each center), 29 cases (11.2%, 29/260) developed anastomotic leak, and in the later phase, 12 cases (4.6%, 12/260) developed anastomotic leak. The difference between the early phase and the later phase was statistically significant (χ(2)=7.652, P=0.006). Conclusion: The incidence of anastomotic leak after taTME may be reduced by using stapler and defunctioning stoma, or by accumulating experience.

Molecular mechanism concerning conformational changes of CDK2 mediated by binding of inhibitors using molecular dynamics simulations and principal component analysis

Cyclin-dependent kinase 2 (CDK2) has been regarded as a promising drug target for anti-tumour agents. In this study, molecular dynamics (MD) simulations and principal component (PC) analysis were used to explore binding mechanism of three inhibitors 1PU, CDK, 50Z to CDK2 and influences of their bindings on conformational changes of CDK2. The results show that bindings of inhibitors yield obvious impacts on internal dynamics, movement patterns and conformational changes of CDK2. In addition, molecular mechanics generalized Born surface area (MM-GBSA) was applied to calculate binding free energies between three inhibitors and CDK2 and evaluate their binding ability to CDK2. The results show that CDK has the strongest binding to CDK2 among the current three inhibitors. Residue-based free energy decomposition method was further utilized to decode the contributions of a single residue to binding of inhibitors, and it was found that three inhibitors not only produce hydrogen bonding interactions and hydrophobic interactions with key residues of CDK2, which promotes binding of three inhibitors to CDK2, but also share similar binding modes. This work is expected to be helpful for design of efficient drugs targeting CDK2.

Evolution of β-lactamases and enzyme promiscuity

β-Lactamases represent one of the most prevalent resistance mechanisms against β-lactam antibiotics. Beyond their clinical importance, they have also become key models in enzymology and evolutionary biochemistry. A global understanding of their evolution and sequence and functional diversity can therefore aid a wide set of different disciplines. Interestingly, β-lactamases have evolved multiple times from distinct evolutionary origins, with ancestries that reach back billions of years. It is therefore no surprise that these enzymes exhibit diverse structural features and enzymatic mechanisms. In this review, we provide a bird's eye view on the evolution of β-lactamases within the two enzyme superfamilies-i.e. the penicillin-binding protein-like and metallo-β-lactamase superfamily-through phylogenetics. We further discuss potential evolutionary origins of each β-lactamase class by highlighting signs of evolutionary connections in protein functions between β-lactamases and other enzymes, especially cases of enzyme promiscuity.

[Clinical efficacy and safety analysis of camrelizumab combined with apatinib as a second-line therapy for unresectable hepatocellular carcinoma: a multicenter retrospective study]

Objective: To analyze the clinical efficacy and safety of camrelizumab combined with apatinib as a second-line therapy for unresectable hepatocellular carcinoma (HCC). Methods: Ninety-four cases with mid-and advanced-stage HCC who received camrelizumab combined with apatinib as second-line treatment were enrolled. Routine blood test, blood biochemical indexes, tumor stage, tumor imaging characteristics, previous treatment strategies and other clinical data before treatment were documented. Imaging examination follow-up results and adverse reactions during treatment were followed up until the end of follow-up or loss of follow-up or death. Kaplan-Meier method was used to analyze the clinical efficacy. Results: As of the last follow-up, 94 cases with mid-and advanced-stage HCC had received camrelizumab combined with apatinib as second-line treatment. Among them, 15 cases were lost to follow-up, 31 cases died, and 48 cases survived. The overall remission rate was 31.9%. The overall disease control rate was 71.3%. The median time to disease-free progression was 6.6 months. The median time to disease progression was not yet available. The 1-year cumulative survival rate was 62.3%. Grade 3 and above adverse reactions mainly included were thrombocytopenia (7.4%), abdominal pain (4.3%), active hepatitis (4.3%), leukopenia (4.3%), diarrhea (3.2%), hand-foot syndrome (3.2%). All adverse reactions were effectively controlled. Conclusion: Camrelizumab combined with apatinib can effectively prolong the survival period of patients with mid-and advanced-stage HCC, and it is well tolerated.

Inhaled Nitric Oxide: In Vitro Analysis of Continuous Flow Noninvasive Delivery via Nasal Cannula

BACKGROUND

Inhaled nitric oxide (NO) is most frequently delivered to mechanically ventilated patients in critical care, but it can also be administered noninvasively. The delivered dose and efficiency of continuous flow NO supplied through a nasal cannula has yet to be established. This study aimed to determine the influence of nasal cannula type, supply flow, and breathing pattern on delivered NO using a realistic adult airway replica and lung simulator.

METHODS

Simulated breathing patterns were selected to represent rest, sleep, and light exercise, and were varied to investigate the effects of tidal volume and breathing frequency independently. Supplied gas flows targeted tracheal concentrations at rest of 5 or 20 ppm NO and were supplied with 2 L/min O₂. Three different cannulas were tested. Tracheal NO concentrations and NO mass flow past the trachea were evaluated.

RESULTS

Cannula type had a minor influence on delivered dose. Tracheal NO concentrations differed significantly based on breathing pattern (P < 0.01); for a target NO concentration of 20 ppm at rest, average inhaled NO concentrations were 23.3 ± 0.5 ppm, 36.5 ± 1.4 ppm, and 17.2 ± 0.3 ppm for the rest, sleep, and light exercise breathing patterns, respectively. For the same test conditions, mass flow of NO past the trachea was less sensitive to breathing pattern: 20.3 ± 0.5 mg/h, 19.9 ± 0.8 mg/h, and 24.3 ± 0.4 mg/h for the rest, sleep, and light exercise breathing patterns, respectively. Mass flow and delivery efficiency increased when minute volume increased.

CONCLUSIONS

These results indicate that inhaled NO concentration is strongly influenced by breathing pattern, whereas inhaled NO mass flow is not. NO mass flow may therefore be a useful dose metric for continuous flow delivery via nasal cannula.

Comprehensive exploration of the translocation, stability and substrate recognition requirements in VIM-2 lactamase

Metallo-β-lactamases (MBLs) degrade a broad spectrum of β-lactam antibiotics, and are a major disseminating source for multidrug resistant bacteria. Despite many biochemical studies in diverse MBLs, molecular understanding of the roles of residues in the enzyme’s stability and function, and especially substrate specificity, is lacking. Here, we employ deep mutational scanning (DMS) to generate comprehensive single amino acid variant data on a major clinical MBL, VIM-2, by measuring the effect of thousands of VIM-2 mutants on the degradation of three representative classes of β-lactams (ampicillin, cefotaxime, and meropenem) and at two different temperatures (25°C and 37°C). We revealed residues responsible for expression and translocation, and mutations that increase resistance and/or alter substrate specificity. The distribution of specificity-altering mutations unveiled distinct molecular recognition of the three substrates. Moreover, these function-altering mutations are frequently observed among naturally occurring variants, suggesting that the enzymes have continuously evolved to become more potent resistance genes.

Pulmonary Delivery of Therapeutic and Diagnostic Gases

The 21st Congress for the International Society for Aerosols in Medicine included, for the first time, a session on Pulmonary Delivery of Therapeutic and Diagnostic Gases. The rationale for such a session within ISAM is that the pulmonary delivery of gaseous drugs in many cases targets the same therapeutic areas as aerosol drug delivery, and is in many scientific and technical aspects similar to aerosol drug delivery. This article serves as a report on the recent ISAM congress session providing a synopsis of each of the presentations. The topics covered are the conception, testing, and development of the use of nitric oxide to treat pulmonary hypertension; the use of realistic adult nasal replicas to evaluate the performance of pulsed oxygen delivery devices; an overview of several diagnostic gas modalities; and the use of inhaled oxygen as a proton magnetic resonance imaging (MRI) contrast agent for imaging temporal changes in the distribution of specific ventilation during recovery from bronchoconstriction. Themes common to these diverse applications of inhaled gases in medicine are discussed, along with future perspectives on development of therapeutic and diagnostic gases.

Comparison of pulsed versus continuous oxygen delivery using realistic adult nasal airway replicas

BACKGROUND

Portable oxygen concentrators (POCs) typically include pulse flow (PF) modes to conserve oxygen. The primary aims of this study were to develop a predictive in vitro model for inhaled oxygen delivery using a set of realistic airway replicas, and to compare PF for a commercial POC with steady flow (SF) from a compressed oxygen cylinder.

METHODS

Experiments were carried out using a stationary compressed oxygen cylinder, a POC, and 15 adult nasal airway replicas based on airway geometries derived from medical images. Oxygen delivery via nasal cannula was tested at PF settings of 2.0 and 6.0, and SF rates of 2.0 and 6.0 L/min. A test lung simulated three breathing patterns representative of a chronic obstructive pulmonary disease patient at rest, during exercise, and while asleep. Volume-averaged fraction of inhaled oxygen (F_iO₂) was calculated by analyzing oxygen concentrations sampled at the exit of each replica and inhalation flow rates over time. POC pulse volumes were also measured using a commercial O₂ conserver test system to attempt to predict F_iO₂ for PF.

RESULTS

Relative volume-averaged F_iO₂ using PF ranged from 68% to 94% of SF values, increasing with breathing frequency and tidal volume. Three of 15 replicas failed to trigger the POC when used with the sleep breathing pattern at the 2.0 setting, and four of 15 replicas failed to trigger at the 6.0 setting. F_iO₂ values estimated from POC pulse characteristics followed similar trends but were lower than those derived from airway replica experiments.

CONCLUSION

For the POC tested, PF delivered similar, though consistently lower, volume-averaged F_iO₂ than SF rates equivalent to nominal PF settings. Assessment of PF oxygen delivery using POC pulse characteristics alone may be insufficient; testing using airway replicas is useful in identifying possible cases of failure and may provide a better assessment of F_iO₂.

[Clinical analysis of delayed epistaxis after craniofacial trauma in 16 patients]

Objective:To investigate the etiology,clinical presentations,diagnosis and treatment of delayed epistaxis after craniocerebral trauma.Method:A retrospective analysis was made including 16 cases who had the traumatic carotid artery injury with massive delayed epistaxis.All of them were finally diagnosed by digital substraction angiography(DSA).Final clinical outcome,radiographic data and follow-up data were analyzed.Result:Two cases of traumatic pesudoaneurysm from internal maxillary artery were embolized with polyvinyl alcohol particles and gelatin sponge.Fourteen cases of traumatic pesudoaneurysm located in ICA cavernous segment was embolized by covered stent.The covered stent placement was successful in all 14 pseudoaneurysms.No procedure-related complications or deaths occurred during follow-up except one of the case with visual field defects and another case with vision loss.Conclusion:Patients with delayed massive epistaxis or recurrent epistaxis after craniofacial trauma which cause pesudoaneurysm should undergo CTA,MRA or DSA examination,and it is would help to get proper diagnosis and treatment as early as possible.No recurrence was found after successful endovascular techniques.

Effect of polychlorinated biphenyls on oxidation stress in the liver of juvenile GIFT, Oreochromis niloticus

The present study clearly showed that chronic exposure to polychlorinated biphenyls (PCBs) at environmentally relevant concentrations can damage juvenile tilapia livers by modulating antioxidant enzyme activities and gene transcription, which affects toxic bioaccumulation and histological congestion. The results suggest that PCBs caused a decrease in the activity of some hepatic antioxidative and biotransformation enzymes (SOD, CAT, GST, T-GSH, and MDA) in tilapia at 7 days, as well as transcriptional changes (sod, cat, and gst). Except for some antioxidant parameters (T-GSH, GSH/GSSG, T-AOC, and MDA), significant declines and increases occurred at 14 and 21 days, respectively. Most of the antioxidant enzymatic signatures and genotoxicity significantly increased at 14 and 21 days. This study presented evidence that PCBs could result in hepatic toxicity through oxidative stress in the early growth stages of tilapia, and we speculated that oxidative stress plays an important role in embryonic developmental toxicity induced by PCBs.

Large-scale tissue-specific and temporal gene expression profiles in Pengze crucian carp

In the present study, the tissue-specific and temporal gene expression profiles of four catalogues of gonadal development-related genes (sex differentiation-related, steroid receptor, steroidogenic, and structural genes) were detected in nine tissues and during 11 successive developmental stages in the Pengze crucian carp (Pcc) (a triploid mono-female gynogenic fish). The results showed that these target genes exhibited overlapping distributions in various tissues, with the exception of Pcc-vasa and Pcc-cyp17a1. Gene expression profiling of the developmental stages showed that all of the target genes simultaneously reached peak expression levels at 40 and 48 days post hatching (dph). Both 40 and 48 dph appeared to be two key time points associated with the process of Pcc gonadal development. These data will provide a clear understanding of gene expression patterns associated with the gonadal development-related genes of this gynogenic teleost.

PTEN hypermethylation profiles of Chinese Kazakh patients with esophageal squamous cell carcinoma

Aberrant DNA methylation of promoter region CpG islands may serve as an alternative mechanism to genetic defects in the inactivation of tumor suppressor genes (TSGs) in human malignancies. The aim of this study was to examine the promoter methylation status of the PTEN TSG and its association with esophageal squamous cell carcinoma (ESCC) carcinogenesis in a Chinese Kazakh population, which is known to have a relatively high ESCC incidence and mortality. The methylation status of the PTEN promoter region was determined in patients with ESCC (n = 95) and healthy individuals (n = 65) using highly sensitive Sequenom Epityper assays. The methylation level of the PTEN gene was significantly higher in patients with ESCC than in healthy controls. The median methylation level was 10.0% (interquartile range [IQR]: 7.0-11.0%) in patients with ESCC and 6.0% in controls (IQR: 4.0-9.0%; P = 0.001). PTEN methylation levels were higher in male patients with ESCC than in male controls, whereas a trend toward significance was observed between female patients with ESCC and female controls (P = 0.005 and P = 0.086, respectively). The PTEN methylation level was associated with histopathological grade and lymph node metastasis in patients with ESCC (P = 0.002 and P = 0.009, respectively). To our knowledge, this is the first report to show the presence of PTEN promoter CpG hypermethylation in ESCC and its association with tumor metastasis.

Development of a novel ArcCHECK(™) insert for routine quality assurance of VMAT delivery including dose calculation with inhomogeneities

PURPOSE

To design a versatile, nonhomogeneous insert for the dose verification phantom ArcCHECK(™) (Sun Nuclear Corp., FL) and to demonstrate its usefulness for the verification of dose distributions in inhomogeneous media. As an example, we demonstrate it can be used clinically for routine quality assurance of two volumetric modulated arc therapy (VMAT) systems for lung stereotactic body radiation therapy (SBRT): SmartArc(®) (Pinnacle(3), Philips Radiation Oncology Systems, Fitchburg, WI) and RapidArc(®) (Eclipse(™), Varian Medical Systems, Palo Alto, CA).

METHODS

The cylindrical detector array ArcCHECK(™) has a retractable homogeneous acrylic insert. In this work, we designed and manufactured a customized heterogeneous insert with densities that simulate soft tissue, lung, bone, and air. The insert offers several possible heterogeneity configurations and multiple locations for point dose measurements. SmartArc(®) and RapidArc(®) plans for lung SBRT were generated and copied to ArcCHECK(™) for each inhomogeneity configuration. Dose delivery was done on a Varian 2100 ix linac. The evaluation of dose distributions was based on gamma analysis of the diode measurements and point doses measurements at different positions near the inhomogeneities.

RESULTS

The insert was successfully manufactured and tested with different measurements of VMAT plans. Dose distributions measured with the homogeneous insert showed gamma passing rates similar to our clinical results (∼99%) for both treatment-planning systems. Using nonhomogeneous inserts decreased the passing rates by up to 3.6% in the examples studied. Overall, SmartArc(®) plans showed better gamma passing rates for nonhomogeneous measurements. The discrepancy between calculated and measured point doses was increased up to 6.5% for the nonhomogeneous insert depending on the inhomogeneity configuration and measurement location. SmartArc(®) and RapidArc(®) plans had similar plan quality but RapidArc(®) plans had significantly higher monitor units (up to 70%).

CONCLUSIONS

A versatile, nonhomogeneous insert was developed for ArcCHECK(™) for an easy and quick evaluation of dose calculations with nonhomogeneous media and for comparison of different treatment planning systems. The device was tested for SmartArc(®) and RapidArc(®) plans for lung SBRT, showing the uncertainties of dose calculations with inhomogeneities. The new insert combines the convenience of the ArcCHECK(™) and the possibility of assessing dose distributions in inhomogeneous media.

Effect of soy isoflavones on blood pressure: a meta-analysis of randomized controlled trials

BACKGROUND AND AIM

The effect of soy isoflavones on blood pressure is controversial. The objective of this study was to evaluate the effect of dietary soy isoflavones on blood pressure.

METHODS AND RESULTS

Trials were searched in PubMed, the Cochrane Library, Embase and references cited in related reviews and studies. A total of eleven trials were reviewed. Meta-analysis results showed a mean decrease of 2.5 mm Hg (95% CIs, - 5.35 to 0.34 mm Hg; P = 0.08) for systolic blood pressure and 1.5 mm Hg (95% CIs, - 3.09 to 0.17 mm Hg; P = 0.08) for diastolic blood pressure in the soy isoflavones-treated group compared to placebo. Meta-regression and subgroup analyses indicated that blood pressure status was a significant predictor of heterogeneity for the effect of soy isoflavones on blood pressure. Subgroup analysis of hypertensive subjects revealed that a greater blood pressure reduction was identified in the soy isoflavone-treated group compared to placebo (5 trials; SBP: - 5.94, 95% CIs [- 10.55, - 1.34] mm Hg, P = 0.01; DBP: - 3.35, 95% CIs [- 6.52, - 0.19] mm Hg, P = 0.04). In contrast, treatment with soy isoflavones did not lead to a significant reduction in blood pressure in normotensive subjects (6 trials; SBP: 0.29, 95% CIs [- 2.39, 2.97] mm Hg, P = 0.83; DBP: - 0.43, 95% CIs [- 1.66, 0.81] mm Hg, P = 0.50).

CONCLUSION

Soy isoflavones had an effect of lowering blood pressure in hypertensive subjects, but not in normotensive subjects. Larger trials need to be carried out to confirm the present findings.

Freshwater toxic cyanobacteria induced DNA damage in apple (Malus pumila), rape (Brassica napus) and rice (Oryza sativa)

Cyanobacteria in freshwater ecosystems can present a harmful effect on growth and development of plants through irrigation with contaminated water. In this study, the effects of microcystins (MCs)-containing cyanobacteria extract (CE) on DNA damage of apple, rape and rice were investigated to explore the phytotoxic mechanism of MCs through DNA fragmentation and RAPD analysis. Determination of DNA fragmentation by fluorescent dye DAPI showed that significant DNA damage was observed in rice seedlings after exposure to CE while DNA fragmentation in rape seedlings and apple cultures did not differ significantly between treatment and control groups. Qualitative characterization of genomic DNA fragmentation by agarose gel electrophoresis supported the quantitative determination using DAPI. The main changes in RAPD profiles of rape seedlings following exposure of lower doses of CE were variation in band intensity for the primers F03 and S01, while higher doses of CE caused loss of normal bands and appearance of new bands except band intensity changes. The data presented here demonstrate that DNA damage in plants occurs following exposure of microcystins, and the polymorphic RAPDs may be used as an investigation tool for environmental toxicology and as a useful biomarker for the detection of genotoxic effects of microcystins on plants.

Does pre-biopsy contrast enema delay the diagnosis of long segment Hirschsprung's disease?

INTRODUCTION

The diagnosis of long segment Hirschsprung's disease (LSHD) is frequently delayed. Our purpose was to: 1) summarize contrast enema (CE) findings in patients with LSHD, and 2) evaluate the utility of CE by comparing LSHD patients managed with/without pre-biopsy CE.

METHODS

All LSHD cases (transition zone [TZ] proximal to the splenic flexure) treated between 1984 and 2009 were stratified according to whether a pre-biopsy CE was done (Group 1) or not (Group 2). CE were reviewed by a single pediatric radiologist, and the original reports were categorized as "helpful", "inconclusive" or "misleading". Group comparisons included elapsed days from admission to diagnostic rectal biopsy/first operation and initial hospitalization length of stay (LOS).

RESULTS

29 patients (16 in Group 1; 13 in Group 2) were identified. CE review revealed TZ in 7/16 (44%); and of these, 6 (86%) underestimated the actual aganglionic segment length. 6/16 (38%) original CE reports were "misleading". Overall, Group 1 patients experienced a significant delay in time to biopsy (p=0.047), first operation (p=0.005), and showed a trend towards prolonged LOS.

CONCLUSIONS

Pre-biopsy CE offers little to the diagnosis of LSHD and may contribute to diagnosis/treatment delays. Even if a TZ is recognized in biopsy proven HD, the predicted aganglionic segment length should not guide the operative planning.

Malignant T cells in cutaneous T-cell lymphoma lesions contain decreased levels of the antiapoptotic protein Ku70

BACKGROUND

Malignant T cells in primary cutaneous T-cell lymphoma (CTCL) are genetically unstable and exhibit prolonged lifespans potentially explained by dysregulation of apoptosis, yet are responsive to apoptosis-inducing therapies. The heterodimeric protein Ku70/80 is known to play a role in DNA repair (Ku70 and Ku80) and inhibition of apoptosis (Ku70 only).

OBJECTIVES

To investigate the expression of Ku70/80 in CD3+ T cells derived from skin and blood in patients with CTCL and normal samples, as well as benign dermatoses.

METHODS

Normal (n=10), CTCL (n=9) and benign dermatoses (n=13) skin samples were stained for confocal imaging of Ku70/80 and CD3 and analysed using imaging software. Circulating CD4+ T cells in normal and CTCL peripheral blood were analysed by flow cytometry and Western blot for Ku70/80 expression (n=6).

RESULTS

Ku70 and Ku80 were significantly diminished in T cells of CTCL lesions relative to T cells of control skin. Decreased T-cell Ku70 expression was not a feature of the benign dermatoses psoriasis and contact dermatitis, suggesting that loss of Ku70/80 in CTCL is not simply the result of cutaneous inflammation. Reduced Ku70 was also noted in circulating CD4+ T cells in patients with CTCL with peripheral blood involvement.

CONCLUSIONS

Deficient expression or lack of Ku70/80 may result in genomic instability and play a role in tumorigenesis, as well as account for the increased susceptibility of malignant T cells to apoptosis-inducing treatment modalities in the setting of intrinsic resistance to apoptosis.

Up-Regulation of CXC Chemokine Receptor 4 Expression in Chronic Atrial Fibrillation Patients with Mitral Valve Disease May Be Attenuated by Renin–Angiotensin System Blockers

This study characterized CXC chemokine receptor 4 (CXCR4) expression in patients with mitral valve disease and chronic atrial fibrillation (AF). Forty-eight patients with chronic AF formed two groups based on whether they were treated with or without renin–angiotensin system (RAS) blockers (AF + RAS group; n = 25, or AF – RAS group; n = 23). The controls comprised 17 mitral valve disease patients with sinus rhythm (SR group). CXCR4 mRNA and protein levels in the left atria were significantly higher in the AF – RAS and AF + RAS groups than in the SR group. CXCR4 expression was significantly lower in the AF + RAS group than the AF – RAS group. More CD34+ cells expressed CXCR4 in the AF – RAS and AF + RAS groups than in the SR group. Angiotensin II, collagen I and left atrial diameter significantly positively correlated with CXCR4 expression in the AF – RAS group. These results suggest that CXCR4 expression is up-regulated in chronic AF patients with mitral valve disease, is associated with atrial remodelling, and that these effects are attenuated by RAS blockers.

More vaccine efficacy studies on the recombinant Bacille Calmette-Guerin co-expressing Ag85B, Mpt64 and Mtb8.4

The immunogenicity of the recombinant Bacille Calmette-Guerin: rBCG-Ag85B-Mpt64(190-198)-Mtb8.4 (rBCG-AMM) was evaluated in our previous study. This paper compares the protective efficacy of rBCG-AMM, rBCG-A which overexpresses Ag85B and BCG in C57BL/6 mice. There was no significant difference in proliferation characteristics among rBCG-AMM, rBCG-A and BCG. The growth characteristics of rBCG-AMM in host tissue were identical to control BCG, suggesting the improved protective efficacy was directly related to the expression of the Ag85B-Mpt64(190-198)-Mtb8.4 fusion protein. The protective experiment demonstrated that rBCG-AMM could confer similar or even better protective efficacy against Mycobacterium tuberculosis infection compared with BCG or rBCG-A as evaluated by bacterial organ loads, lung histopathology and net weight gain or loss. The results suggested that the recombinant BCG: rBCG-Ag85B-Mpt64(190-198)-Mtb8.4 is a potential vaccine candidate for further study.

Resveratrol reduces endothelial progenitor cells senescence through augmentation of telomerase activity by Akt-dependent mechanisms

BACKGROUND AND PURPOSE

Recent studies have shown that resveratrol increased endothelial progenitor cells (EPCs) numbers and functional activity. However, the mechanisms remain to be determined. Previous studies have demonstrated that increased EPC numbers and activity were associated with the inhibition of EPC senescence, which involves activation of telomerase. Therefore, we investigated whether resveratrol inhibits the onset of EPC senescence through telomerase activation, leading to potentiation of cellular activity.

EXPERIMENTAL APPROACH

After prolonged in vitro cultivation, EPCs were incubated with or without resveratrol. The senescence of EPCs were determined by acidic beta-galactosidase staining. The bromo-deoxyuridine incorporation assay or a modified Boyden chamber assay were employed to assess proliferative or migratory capacity, respectively. To further examine the underlying mechanisms of these effects, we measured telomerase activity and the phosphorylation of Akt by western blotting.

KEY RESULTS

Resveratrol dose dependently prevented the onset of EPCs senescence and increased the proliferation and migration of EPCs. The effect of resveratrol on senescence could not be abolished by eNOS inhibitor or by an oestrogenic receptor antagonist. Resveratrol significantly increased telomerase activity and Akt phosphorylation. Pre-treatment with the PI3K inhibitor, LY294002, significantly attenuated resveratrol-induced telomerase activity.

CONCLUSIONS AND IMPLICATIONS

Resveratrol delayed the onset of EPC senescence and this effect was accompanied by activation of telomerase through the PI3K-Akt signalling pathway. The inhibition of EPCs senescence by resveratrol might protect EPCs against dysfunction induced by pathological factors in vivo and improve EPC functional activities in a way that may be important for cell therapy.

Homocysteine accelerates senescence and reduces proliferation of endothelial progenitor cells

Our previous studies showed that homocysteine (Hcy) reduces endothelial progenitor cell (EPC) numbers and impairs functional activity. However, the mechanisms by which Hcy reduces EPCs numbers and activity remain to be determined. Recent studies have demonstrated that reduced EPCs numbers and activity was associated with EPCs senescence which involved telomerase activity. Therefore, we investigated whether Hcy accelerates the onset of EPCs senescence through telomerase inactivation, leading to cellular dysfunction. EPCs were isolated from peripheral blood and characterized. After ex vivo cultivation, EPCs became senescent as determined by acidic beta-galactosidase staining. Hcy dose-dependently accelerated the onset of EPCs senescence in culture. Moreover, Hcy decreased proliferation of EPCs as assessed by BrdU incorporation assay and colony-forming capacity. To get further insights into the underlying mechanisms of these effects induced by Hcy, we measured telomerase activity and determined the phosphorylation of Akt by using western blot. Hcy significantly diminished telomerase activity and Akt phosphorylation. Taken together, the results of the present study demonstrated that Hcy accelerated the onset of EPCs senescence, leading to cellular dysfunction. The effect of Hcy might be dependent on telomerase inactivation, and Akt dephosphorylation also appeared to play a major role. In addition, atorvastatin had a preventative effect against Hcy-induced EPCs senescence.

Effects of rapamycin on number activity and eNOS of endothelial progenitor cells from peripheral blood

The aim of this investigation is to determine whether rapamycin treatment has any effect on endothelial progenitor cells (EPCs). Total mononuclear cells (MNCs) were isolated from peripheral blood by Ficoll density gradient centrifugation, and then the cells were plated on fibronectin-coated culture dishes. After 7 days in culture, attached cells were stimulated with rapamycin (in a series of final concentrations: 0.1, 1.0, 2.0 and 5.0 g/ml) for 6, 12, 24 and 48 h. EPCs were characterized as adherent cells, double positive for DiLDL uptake and lectin binding by direct fluorescence staining. EPC proliferation and migration were determined using the MTT assay and a modified version of the Boyden chamber assay, respectively. An EPC adhesion assay was performed by replating the cells on fibronectin-coated dishes; adherent cells were then counted. Tube formation activity was assayed by using a tube formation assay kit and endothelial nitric oxide synthase (eNOS) was assayed by Western blot analysis. Incubation of isolated human MNCs with rapamycin decreased the number of EPCs present; rapamycin also decreased EPCs proliferative, migratory, adhesive, tube formation capacity and eNOS production in a concentration- and time-dependent manner. Rapamycin was found to decrease the number, proliferative, migratory, adhesive and tube formation capacities of the EPCs, and also was found to decreases eNOS in the EPCs.

Feasibility of a fast inverse dose optimization algorithm for IMRT via matrix inversion without negative beamlet intensities

A fast optimization algorithm is very important for inverse planning of intensity modulated radiation therapy (IMRT), and for adaptive radiotherapy of the future. Conventional numerical search algorithms such as the conjugate gradient search, with positive beam weight constraints, generally require numerous iterations and may produce suboptimal dose results due to trapping in local minima. A direct solution of the inverse problem using conventional quadratic objective functions without positive beam constraints is more efficient but will result in unrealistic negative beam weights. We present here a direct solution of the inverse problem that does not yield unphysical negative beam weights. The objective function for the optimization of a large number of beamlets is reformulated such that the optimization problem is reduced to a linear set of equations. The optimal set of intensities is found through a matrix inversion, and negative beamlet intensities are avoided without the need for externally imposed ad-hoc constraints. The method has been demonstrated with a test phantom and a few clinical radiotherapy cases, using primary dose calculations. We achieve highly conformal primary dose distributions with very rapid optimization times. Typical optimization times for a single anatomical slice (two dimensional) (head and neck) using a LAPACK matrix inversion routine in a single processor desktop computer, are: 0.03 s for 500 beamlets; 0.28 s for 1000 beamlets; 3.1 s for 2000 beamlets; and 12 s for 3000 beamlets. Clinical implementation will require the additional time of a one-time precomputation of scattered radiation for all beamlets, but will not impact the optimization speed. In conclusion, the new method provides a fast and robust technique to find a global minimum that yields excellent results for the inverse planning of IMRT.

Influence of interleukin-2 on Ca2+ handling in rat ventricular myocytes

In the present study, we examined the effect of interleukin-2 (IL-2) on cardiomyocyte Ca(2+) handling. The effects of steady-state and transient changes in stimulation frequency on the intracellular Ca(2+) transient were investigated in isolated ventricular myocytes by spectrofluorometry. In the steady state (0.2 Hz) IL-2 (200 U/ml) decreased the amplitude of Ca(2+) transients induced by electrical stimulation and caffeine. At 1.25 mM extracellular Ca(2+) concentration ([Ca(2+)](o)), when the stimulation frequency increased from 0.2 to 1.0 Hz, diastolic Ca(2+) level and peak intracellular Ca(2+) concentration ([Ca(2+)](i)), as well as the amplitude of the transient, increased. The positive frequency relationships of the peak and amplitude of [Ca(2+)](i) transients were blunted in the IL-2-treated myocytes. The effect of IL-2 on the electrically induced [Ca(2+)](i) transient was not normalized by increasing [Ca(2+)](o) to 2.5 mM. IL-2 inhibited the frequency relationship of caffeine-induced Ca(2+) release. Blockade of sarcoplasmic reticulum (SR) Ca(2+)-ATPase with thapsigargin resulted in a significant reduction of the amplitude-frequency relationship of the transient similar to that induced by IL-2. The restitutions were not different between control and IL-2 groups at 1.25 mM [Ca(2+)](o), which was slowed in IL-2-treated myocytes when [Ca(2+)](o) was increased to 2.5 mM. There was no difference in the recirculation fraction (RF) between control and IL-2-treated myocytes at both 1.25 and 2.5 mM [Ca(2+)](o). The effects of IL-2 on frequency relationship, restitution, and RF may be due to depressed SR functions and an increased Na(+)-Ca(2+) exchange activity, but not to any change in L-type Ca(2+) channels.

A study of mixing in thermocapillary flows on micropatterned surfaces

The recent introduction of actuation mechanisms for microfluidic transport based on free surface flows raises a number of interesting questions involving efficient mixing configurations, especially in systems with small aspect ratios. This work investigates the characteristics of convective and diffusive mixing in continuous-mode streaming of thermocapillary microflows on chemically micropatterned surfaces. Mixing times and mixing lengths relevant to chemical microreactors or gas sensors are investigated for various geometries and parameter ranges. Scaling arguments and full numerical solutions are presented to extract optimal operating conditions. Confocal fluorescence microscopy measurements of the interfacial diffusive broadening in adjacent flowing streams confirm numerical predictions. Three important mixing regimes, based on analogues of purely diffusive dynamics, Rhines-Young shear-augmented diffusion and Taylor-Aris dispersion are identified and investigated for use in free surface flows with large surface-to-volume ratios.

Simplified intensity-modulated arc therapy for dose escalated prostate cancer radiotherapy

Simplified intensity-modulated arc therapy (SIMAT) employs forward planned, conformal, and avoidance arc combinations with dynamic multileaf collimation (MLC) as a simpler alternative to other forms of intensity-modulated radiotherapy (IMRT). In this work, we compare SIMAT with 4-field (4F) and 6-field (6F) 3D conformal radiation therapy (CRT) for prostate cancer treatment. Prostate, seminal vesicle, bladder, and rectum were contoured on the CT images of 10 patients being planned for radiotherapy. Two planning target volumes (PTV) were defined: PTV1 (prostate + seminal vesicles + 1.0-cm margin) and PTV2 (prostate + 1.0-cm margin). SIMAT, 4F, and 6F plans were generated with a prescription dose of 78 Gy to prostate and 54 Gy to the seminal vesicles. Differences in the 3 techniques in terms of target and rectal coverage were compared. In addition, dose distributions of the SIMAT plans were verified with measurements in a phantom. Mean dose to PTV2 (4F, 76 Gy; 6F, 78 Gy; SIMAT, 76 Gy) and the dose delivered to 95% of the target volume (D(95)) were similar between the 3-techniques. Target conformity was better with SIMAT. Mean dose and calculated NTCP for the rectum were lower for SIMAT than those for 4F and 6F plans (4F 55.6 Gy vs. 6F 49.0 Gy vs. SIMAT 42.7 Gy). Mean dose to femoral heads was lower for the 4F technique vs. 6F and SIMAT techniques (4F 44.5 Gy vs. 6F 48.9 Gy vs. SIMAT 49.5 Gy). In-phantom measurement demonstrated good agreement between the plans and SIMAT treatments delivered in phantom. We concluded that SIMAT demonstrates advantages over 4F and 6F in terms of target conformity mean rectal dose and NTCP with good reproducibility in phantom. On the basis of this analysis, we have commenced a clinical pilot study of SIMAT for prostate cancer radiotherapy.

Effects of homocysteine on number and activity of endothelial progenitor cells from peripheral blood

The aim of this study is to investigate whether homocysteine (Hcy) has influences on endothelial progenitor cells (EPCs) number and activity. Total mononuclear cells (MNCs) were isolated from peripheral blood by Ficoll density gradient centrifugation, and then the cells were plated on fibronectin-coated culture dishes. After 7 d cultured, attached cells were stimulated with Hcy (to make a series of final concentrations: 10, 50, 100 and 200 micromol/l) or vehicle control for the respective time points (6, 12, 24 and 48 h). EPCs were characterized as adherent cells double positive for DiLDL uptake and lectin binding by direct fluorescent staining under a laser scanning confocal microscope. EPCs proliferation, migration and in vitro vasculogenesis activity were assayed with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, modified Boyden chamber assay and in vitro vasculogenesis kit, respectively. EPCs adhesion assay was performed by replating those on fibronectin-coated dishes, and then adherent cells were counted. Incubation of isolated human MNCs with Hcy dose and time dependently decreased the number of EPCs, maximum at 200 micromol/l, 24 h (approximately 50% reduction, P < 0.01). In addition, Hcy dose and time dependently impaired EPC proliferative, migratory, adhesive and in vitro vasculogenesis capacity. In conclusion, hyperHcy may induce the reduction of EPCs with decreased functional activity.

Helical structures in proteins

We examine a minimal model for helix-forming polymers. The monomer-monomer potential energy is based on the anisotropic potentials seen in proteins and is used in conjunction with a wormlike backbone. We show that the coil-helix transition involves four states. As the temperature is lowered, the first observed state is a coil state, the second a collapsed globular, the third a highly flexible helical state, and the fourth a crystalline helical state. We discuss in detail what effect the potential energy form has on these various states by systematically varying the potential from strongly anisotropic to isotropic. The data demonstrate that the foldability of a helix is strongly related to anisotropic nature of the potential. In the isotropic case, we show that the transition following a globular collapse is not first order as postulated for these systems. In the strongly anisotropic case the globular-helix transition is consistent with cooperative first-order-like behavior.

Significance of local electrostatic interactions in staphylococcal nuclease studied by site-directed mutagenesis

In this paper, we show that amino acids Glu(73) and Asp(77) of staphylococcal nuclease cooperate unequally with Glu(75) to stabilize its structure located between the C-terminal helix and beta-barrel of the protein. Amino acid substitutions E73G and D77G cause losses of the catalytic efficiency of 24 and 16% and cause thermal stability losses of 22 and 26%, respectively, in comparison with the wild type (WT) protein. However, these changes do not significantly change global and local secondary structures, based on measurements of fluorescence and CD(222 nm). Furthermore, x-ray diffraction analysis of the E75G protein shows that the overall structure of mutant and WT proteins is similar. However, this mutation does cause a loss of essential hydrogen bonding and charge interactions between Glu(75) and Lys(9), Tyr(93), and His(121). In experiments using double point mutations, E73G/D77G, E73G/E75G, and E75G/D77G, significant changes are seen in all mutants in comparison with WT protein as measured by fluorescence and CD spectroscopy. The losses of thermal stability are 47, 59, and 58%, for E73G/D77G, E73G/E75G, and E75G/D77G, respectively. The triple mutant, E73G/E75G/D77G, results in fluorescence intensity and CD(222 nm) close to those of the denatured state and in a thermal stability loss of 65% relative to the WT protein. Based on these results, we propose a model in which significant electrostatic interactions result in the formation of a locally stable structure in staphylococcal nuclease.

[Study of the reproducibility and sensitivity of laser microspectral analysis in argon atmosphere at reduced pressure]

In argon atmosphere at reduced pressure, the spectral analysis reproducibility and sensitivity are experimentally studied with the laser microprobe emission spectral analysis(LMESA) system for the metal alloy standard samples. For the atomic spectral analysis line, the relative standard deviation(RSD) in argon atmosphere at reduced pressure is better than that in air atmosphere. For the ionic spectral analysis line, the RSD is almost the same in both cases. The RSD is strongly affected by the composition of the sample and the concentration of elements. The measured slope of calibration curves for the determination of Cu, Zn and Mg in an aluminum alloy in argon atmosphere is about 1.5-2 times of that in the air atmosphere, which indicates an obvious improvement of the sensitivity and is helpful to expand the dynamic range of the spectral analysis.

A two-source model for electron beams: calculation of relative output factors

A two-source model for the calculation of relative output factors (ROF) for clinical applications of electron beams has been developed. The model consists of (1) an effective extended source above the final field-defining aperture (cutout) plane and (2) a source due to scattering from the aperture. Calculations are based on Fermi-Eyges theory and a pencil beam algorithm with parameters determined independently for each major scattering component. The model predicts a modified inverse square law for determining the dose rate for the electron beams. It also generalizes the "square-root method" and "one-dimensional method" that are often used clinically for ROF calculations. A computer program based on the model has been developed to calculate ROF for irregular fields. The predictions of ROF values have been compared with measurements on a Varian CLINAC 2100C/D accelerator for different cutout size, energies, applicators, and SSDs for square fields, rectangular fields, circular fields, and irregular fields. The agreement between prediction and measurement of the ROF for these wide range of conditions is generally within 1% for energies from 6 to 20 MeV. This two-source model can be used for clinical applications and it requires a minimal set of measured input data.

[Probe into the virtual medical instruments]

With the use of 3DSMAX and AUTO CAD 2000, we have practiced the dynamic simulation of the virtual medical instrument, which is very useful in design. The engineer and doctor can watch a product and change it before making so as to save the time of design and to improve the quality.

The effects of sensitization and hypersensitivity reaction on transepithelial antigen transport of rat nasal mucosa

METHODS

The prevalence of airway allergy is very high. The ways that antigen passes across the airway tract epithelial barrier are not well understood. This study uses a model antigen, horseradish peroxidase (HRP), to sensitize and challenge the respiratory tract in the rat model.

RESULTS

The results showed increases in HRP endosomes in nasal epithelial cells 5 minutes after HRP challenge in the sensitized rats compared with controls, which were further increased 30 minutes after HRP challenge, as well as with the paracellular region filled with HRP products. Meanwhile, mast cells were activated as shown by degranulation. Analysis of cell type showed that there were many more HRP endosomes in the nonciliated cells and there were many more nonciliated cells in the nasal mucosa of the sensitized rats.

CONCLUSION

The results demonstrate that sensitization promotes airway mucosal epithelial cells' uptake and transport of specific antigen and that mast cells may play certain roles in this process.

Abnormal gastric slow waves in patients with functional dyspepsia assessed by multichannel electrogastrography

The aim of this study was to utilize multichannel electrogastrography to investigate whether patients with functional dyspepsia had impaired propagation or coordination of gastric slow waves in the fasting state compared with healthy controls. The study was performed in 10 patients with functional dyspepsia and 11 healthy subjects. Gastric myoelectrical activity was measured by using surface electrogastrography with a specially designed four-channel device. The study was performed for 30 min or more in the fasting state. Special computer programs were developed for the computation of the propagation and coupling of the gastric slow wave. It was found that, compared with the healthy controls, the patients showed a significantly lower percentage of slow wave propagation (58.0 +/- 8.9 vs. 89.9 +/- 2.6%, P < 0.002) and a significantly lower percentage of slow wave coupling (46.9 +/- 4.4 vs. 61.5 +/- 6.9%, P < 0.04). In addition, the patients showed inconsistencies in the frequency and regularity of the gastric slow wave among the four-channel electrogastrograms (EGGs). It was concluded that patients with functional dyspepsia have impaired slow wave propagation and coupling. Multichannel EGG has more information than single-channel EGG for the detection of gastric myoelectrical abnormalities.

Fluorescence-based directed termination PCR: direct mutation characterization without sequencing

We describe a fluorescence-based directed termination PCR (fluorescent DT-PCR) that allows accurate determination of actual sequence changes without dideoxy DNA sequencing. This is achieved using near infrared dye-labeled primers and performing two PCR reactions under low and unbalanced dNTP concentrations. Visualization of resulting termination fragments is accomplished with a dual dye Li-cor DNA sequencer. As each DT-PCR reaction generates two sets of terminating fragments, a pair of complementary reactions with limiting dATP and dCTP collectively provide information on the entire sequence of a target DNA, allowing an accurate determination of any base change. Blind analysis of 78 mutants of the supF reporter gene using fluorescent DT-PCR not only correctly determined the nature and position of all types of substitution mutations in the supF gene, but also allowed rapid scanning of the signature sequences among identical mutations. The method provides simplicity in the generation of terminating fragments and 100% accuracy in mutation characterization. Fluorescent DT-PCR was successfully used to generate a UV-induced spectrum of mutations in the supF gene following replication on a single plate of human DNA repair-deficient cells. We anticipate that the automated DT-PCR method will serve as a cost-effective alternative to dideoxy sequencing in studies involving large-scale analysis for nucleotide sequence changes.