Uncovering the armpit of SBRT: An institutional experience with stereotactic radiation of axillary metastases.

Purpose/objectives: The growing use of stereotactic body radiotherapy (SBRT) in metastatic cancer has led to its use in varying anatomic locations. The objective of this study was to review our institutional SBRT experience for axillary metastases (AM), focusing on outcomes and process. Materials/methods: Patients treated with SBRT to AM from 2014 to 2022 were reviewed. Cumulative incidence functions were used to estimate the incidence of local failure (LF), with death as competing risk. Kaplan-Meier method was used to estimate progression-free (PFS) and overall survival (OS). Univariate regression analysis examined predictors of LF. Results: We analyzed 37 patients with 39 AM who received SBRT. Patients were predominantly female (60 %) and elderly (median age: 72). Median follow-up was 14.6 months. Common primary cancers included breast (43 %), skin (19 %), and lung (14 %). Treatment indication included oligoprogression (46 %), oligometastases (35 %) and symptomatic progression (19 %). A minority had prior overlapping radiation (18 %) or surgery (11 %). Most had prior systemic therapy (70 %).Significant heterogeneity in planning technique was identified; a minority of patient received 4-D CT scans (46 %), MR-simulation (21 %), or contrast (10 %). Median dose was 40 Gy (interquartile range (IQR): 35-40) in 5 fractions, (BED10 = 72 Gy). Seventeen cases (44 %) utilized a low-dose elective volume to cover remaining axilla.At first assessment, 87 % had partial or complete response, with a single progression. Of symptomatic patients (n = 14), 57 % had complete resolution and 21 % had improvement. One and 2-year LF rate were 16 % and 20 %, respectively. Univariable analysis showed increasing BED reduced risk of LF. Median OS was 21.0 months (95 % [Confidence Interval (CI)] 17.3-not reached) and median PFS was 7.0 months (95 % [CI] 4.3-11.3). Two grade 3 events were identified, and no grade 4/5. Conclusion: Using SBRT for AM demonstrated low rates of toxicity and LF, and respectable symptom improvement. Variation in treatment delivery has prompted development of an institutional protocol to standardize technique and increase efficiency. Limited followup may limit detection of local failure and late toxicity.

[Incidence and risk factors of congenital ventricular septal defect in Qingdao].

Objective: To analyze the incidence and risk factors of ventricular septal defect (VSD) in Qingdao. Methods: A prospective cohort study design was used to include pregnant women who underwent prenatal screening in Qingdao between August 2018 and June 2020 (the whole population coverage). VSD was diagnosed according to the pulse oxygen saturation and heart auscultation, and the final diagnosis was made according to the echocardiography of VSD positive newborns within postnatal day 7. Results: The study included 115 238 live births, among which 388 were diagnosed as VSD, with an incidence of 3.37‰. The results of multivariate logistic regression analysis showed that mother with postgraduate level (OR=1.61, 95%CI: 1.00-2.58, P=0.049) (compared with junior high school and below), preterm birth history (OR=2.90, 95%CI: 1.47-5.70, P=0.002), and pregnancy history of congenital heart disease (OR=5.98, 95%CI: 2.63-14.73, P<0.001) were risk factors for VSD. Compared with female infants, the overall risk of VSD in male infants was relatively low (OR=0.74, 95%CI: 0.60-0.91, P=0.005). Conclusions: The incidence of VSD in Qingdao is 3.37‰. The risk factors of VSD include higher maternal education level, pregnancy history of congenital heart disease and preterm birth history. Moreover, the overall risk of VSD in male infants is low.

[Risk factors analysis and the development and validation of a clinical prediction model for acute mesenteric ischemia-induced intestinal infarction].

Objective: To investigate the risk factors of intestinal infarction caused by acute mesenteric ischemia (AMI), and develop and validate a clinical prediction model of Nomogram plot for intestinal infarction caused by AMI. Methods: From January 2014 to December 2020, 201 patients with AMI in the Affiliated Hospital of Yunnan University were selected as the modeling group, and 105 patients with AMI in the First Affiliated Hospital of Kunming Medical University were collected as the validation group. The age of patients in the modeling group was (62±12) years, and there were 70 males and 131 females. The age of patients in the validation group was (62±10) years old, and there were 69 males and 36 females. The clinical data including clinical manifestations, laboratory indicators and imaging indicators of patients in the two groups were retrospectively analyzed, and univariate and multivariate binary logistic regression analyses were performed to screen out risk factors for the progression of AMI to intestinal infarction. A Nomogram plot clinical prediction model for AMI causing intestinal infarction was developed using R software, and the differentiation, calibration and net clinical benefit of this Nomogram plot were evaluated by C-index, calibration curve and clinical decision analysis curve. Results: Shock (OR=13.69, 95%CI: 2.31-88.87), body temperature ≥38.0 ℃ (OR=6.39, 95%CI: 1.85-22.11), white blood cells (WBC) ≥18×109/L (OR=1.19, 95%CI: 1.03-1.37), intestinal changes on CT (OR=0.17, 95%CI: 0.04-0.66), peritoneal irritation (OR=0.06, 95%CI: 0.01-0.26), and pH≤7.34 (OR=0.00, 95%CI: 0.00-0.01) were risk factors for intestinal infarction caused by AMI. Body temperature ≥38.0 ℃ (sensitivity: 81.5%, specificity: 87.0%), WBC ≥18×109/L (sensitivity: 84.0%, specificity: 83.0%) and pH ≤7.34 (sensitivity: 70.4%, specificity: 76.7%) were cut-off values for progression to intestinal infarction in patients with AMI. The Nomogram plot prediction model of intestinal infarction induced by AMI was established by using the above parameters and validated internally and externally. The C index of validation group and modeling group were 0.96 (95%CI: 0.921-0.999) and 0.98 (95%CI: 0.962-0.996), respectively. The calibration curves of the validation group and the modeling group were shaped near the reference line, and the deviation from the reference line was low. The clinical decision analysis curves of validation group and modeling group showed that the clinical prediction model of Nomogram could bring better clinical net benefit for AMI patients. Conclusions: Shock, temperature, white blood cells, intestinal changes on CT, peritoneal irritation sign, and PH are independent risk factors for AMI-induced intestinal infarction. The Nomogram plot established by these factors can effectively predict the probability of AMI patients progressing to intestinal infarction.

Maxillary molar root and canal morphology of Neolithic and modern Chinese.

OBJECTIVE: This study aimed to characterize Neolithic human maxillary molars from archeological remains at the Jiaojia site, Shandong, China, and compare their ultrastructural features with sex and age-matched modern locals. DESIGN: Maxillary first (n = 86) and second (n = 80) molars in 5000-year-old individuals (n = 50) from the Jiaojia site were scanned by cone-beam computed tomography (CBCT). Sex and age-matched control groups were assigned from oral surgical patients at Shandong University. Images were analyzed for crown size, root length, root morphology, canal inter-orifice distances, mesiobuccal canal morphology, and second mesiobuccal (MB2) canal prevalence and location. Neolithic and modern values were compared statistically using Chi-squared and Mann-Whitney test at p < .05. RESULTS: Crown and root size were smaller, and canal inter-orifice distances were shorter in Neolithic maxillary molars than their modern counterparts. For mesiobuccal roots, Weine's Type I single canals were the most prevalent in Neolithic and modern first and second molars. MB2 canal prevalence were not significantly different (p > .05) in Neolithic (53.3%) or modern (60.5%) first molars, and Neolithic (11.3%) or modern (21.3%) second molars. But, MB2 prevalence was significantly higher for modern than ancient male first (p = .032) and second (p = .005) molars. Additionally, MB2 were located more mesially and closer to MB1 in Neolithic than modern molars. CONCLUSIONS: Maxillary molar root and canal morphology of ancient 5000-year-old remains at the Jiaojia site resemble that of local patients. A trend towards larger tooth size, and more dispersed MB2 canals over this short evolutionary period warrants additional investigation.

MR Diffusional Kurtosis Imaging-Based Assessment of Brain Microstructural Changes in Patients with Moyamoya Disease before and after Revascularization.

BACKGROUND AND PURPOSE: Conventional imaging examinations are insufficient to accurately assess brain damage in patients with Moyamoya disease. Our aim was to observe brain microstructural changes in patients with Moyamoya disease by diffusional kurtosis imaging and provide support data for application of this technique in individualized assessment of disease severity and surgical outcome among patients with Moyamoya disease. MATERIALS AND METHODS: A total of 64 patients with Moyamoya disease and 15 healthy volunteers underwent diffusional kurtosis imaging, and a second scanning was offered to surgical patients 3-4 months after revascularization. The diffusional kurtosis imaging parameter maps were obtained for mean kurtosis, axial kurtosis, radial kurtosis, fractional anisotropy, mean diffusivity, axial diffusivity, and radial diffusivity. The parameter values were measured in sensory pathway-related regions for all subjects. Differences in diffusional kurtosis imaging parameters of these brain regions were examined for healthy volunteers, patients without acroparesthesia, and asymptomatic and symptomatic sides of patients with acroparesthesia. Changes in diffusional kurtosis imaging parameters of patients with Moyamoya disease before and after revascularization were compared. RESULTS: Compared with healthy volunteers, patients with Moyamoya disease showed decreased mean kurtosis, axial kurtosis, radial kurtosis, and fractional anisotropy in the corona radiata. Similarly, mean kurtosis, radial kurtosis, and fractional anisotropy decreased in the posterior limb of the internal capsule, whereas axial kurtosis decreased and radial kurtosis increased in the thalami of patients with Moyamoya disease compared with healthy volunteers. Compared with the asymptomatic contralateral hemisphere, the symptomatic group showed increased mean kurtosis in the contralateral primary somatosensory cortex, increased fractional anisotropy in the contralateral corona radiata and posterior limb of the internal capsule, and decreased axial kurtosis in the contralateral thalamus. Among patients with Moyamoya disease with acroparesthesia, mean kurtosis decreased in the primary somatosensory cortex on the operated side following revascularization. CONCLUSIONS: The diffusional kurtosis imaging technique is applicable to patients with Moyamoya disease for detecting brain microstructural changes in white and gray matter before and after revascularization; this feature is useful in the assessment of disease severity and surgical outcome.

[Effects of smoking cessation on the risk of hypertension: a meta-analysis].

Objective: To estimate the effect of smoking cessation on the risk of hypertension. Methods: Literature search of PubMed, Embase, Vip and CNKI between 2001 and 2016 was performed to retrieve prospective cohort studies assessing the relative risks (RR) of smoking cessation and current smoking on hypertension. The pooled RR with 95% confidence intervals (CI) were calculated using random effects models, and subgroup analyses were employed based on participants and study characteristics. Results: A total of 8 eligible prospective cohort studies with 70 130 participants and 21 238 incident cases of hypertension were retrieved. The individuals aged 25-84 years, among them, 53.64% (37 618/70 130) were men and the follow-up period were 4-14.5 years. The pooled RR of hypertension was 1.08 (95%CI: 0.94-1.20) for comparing smoking cessation with current smoking and the pooled adjusted RR was 0.91 (95%CI: 0.33-2.50) (both P>0.05). Conclusions: Smoking cessation did not increased risks of hypertension. Therefore, effective strategies are needed to encourage smokers to quit.

A variant of HLA-DRB1*11, HLA-DRB1*11:143, discovered in a Chinese hematopoietic stem cell donor.

HLA-DRB1*11:143 has one nucleotide change from HLA-DRB1*11:01:01 where Aspartic Acid (70) is changed to Glycine.

Long-term effectiveness of plasma-derived hepatitis B vaccine 22-28 years after immunization in a hepatitis B virus endemic rural area: is an adult booster dose needed?

Longan County is considered a highly endemic area for hepatitis B virus (HBV). The plasma-derived vaccine has been used in newborns in this area since 1987. A cross-sectional survey was conducted to evaluate the long-term effectiveness of this vaccine. In total, 1634 participants born during 1987-1993 and who had received a series of plasma-derived HB vaccinations at ages 0, 1, and 6 months were enrolled. Serological HBV markers were detected and compared with previous survey data. Overall the prevalence of hepatitis B surface antigen (HBsAg) in all participants was 3·79%; 3·47% of subjects who had received the first dose within 24 h were HBsAg positive, and 8·41% of subjects who had received a delayed first dose were also HBsAg positive. There were 1527 subjects identified who had received the first dose within 24 h and whose HBsAg and anti-HBc prevalence increased yearly after immunization, while the anti-HBs-positive rate and vaccine effectiveness declined. The geometric mean concentration of antibody in the anti-HB-positive participants was 55·13 mIU/ml and this declined after immunization. Fewer than 2·0% of participants had anti-HB levels ⩾1000 mIU/ml. The data show that the protective efficacy of the plasma-derived vaccinations declined and administration of HB vaccine within 24 h of birth was very important. To reduce the risk of HBV infection in this highly endemic area, a booster dose might be necessary if anti-HBs levels fall below 10 mIU/ml after age 18 years. Furthermore, studies on the immune memory induced by plasma-derived HB vaccine are needed.

MiR-183 modulates multi-drug resistance in hepatocellular cancer (HCC) cells via miR-183-IDH2/SOCS6-HIF-1α feedback loop.

OBJECTIVE: MiR-183 acts as an oncomiR and is usually upregulated in hepatocellular cancer (HCC). This study aims to study the association between miR-183 dysregulation and multi-drug resistance (MDR). Also, how it is dysregulated in HCC cells was investigated. MATERIALS AND METHODS: The association between miR-183 and HIF-1α in HCC cell line BEL-7402 and the multidrug-resistant variant BEL-7402/5-fluorouracil (BEL-7402/5-FU) were studied using qRT-PCR and Western blot analysis. The mediators involved in feedback regulation between miR-183 and HIF-1α were further studied. Then, the effect of the miR-183-SOCS6 axis on IC50 of BEL-7402/5-FU cells to 5-FU were investigated by MTT assay. RESULTS: The expression of miR-183 and HIF-1α are positively correlated in BEL-7402 and BEL-7402/5-FU cells. IDH2 knockdown resulted in significantly increased HIF-1α expression in both BEL-7402 and BEL-7402/5-FU cells. Knockdown of SOCS6 had similar but stronger effect as miR-183 in promoting MRP2, P-gp, p-STAT3 and HIF-1α expression in BEL-7402 cells, while SOCS6 overexpression also showed similar but stronger effect as miR-183 inhibition in reducing MRP2, P-gp, p-STAT3 and HIF-1α levels in BEL-7402/5-FU cells. Both SOCS6 overexpression and miR-183 knockdown significantly increased the sensitivity of BEL-7402/5-FU cells to 5-FU. MiR-183 overexpression partly abrogated the effect of SOCS6 in enhancing 5-FU sensitivity. CONCLUSIONS: Both HIF-1α-miR-183-IDH2-HIF-1α and HIF-1α-miR-183-SOCS6-p-STAT3-HIF-1α feedback loops are involved in miR-183 upregulation in HCC cells. MiR-183 can modulate MDR of HCC cells at least partly through suppressing SOCS6.

A new HLA-A allele, HLA-A*11:120, sequenced in a Chinese hematopoietic stem cell donor.

HLA-A*11:120 has one nucleotide change from HLA-A*11:01:01:01 where 295 T(ACC) is changed to S(AGC).

Correlation between vascular endothelial growth factor and quantitative dual-energy spectral CT in non-small-cell lung cancer.

AIM: To explore the correlation between the expression level of vascular endothelial growth factor (VEGF) in non-small-cell lung cancer (NSCLC) tissue and quantitative parameters of spectral computed tomography (CT) imaging. MATERIALS AND METHODS: Forty-eight patients with NSCLC underwent a spectral CT imaging protocol before surgical tumour resection. The repetition of iodine concentration, water concentration, and CT values at 40 keV in the region of interest were measured. The slopes of spectral attenuation curves (λHU) in the region were also calculated. The level of VEGF expression in the tumour tissue was measured using an immunohistochemical method (MaxVision method). The quantitative parameters of spectral CT imaging were compared among different levels of VEGF expression using one-way analysis of variance (ANOVA) and least significant difference (SLD) test. The correlation between VEGF expression and spectral CT imaging was estimated through Spearman's rank correlation analysis. RESULTS: There were significant differences in iodine concentrations, λHU, and CT values at 40 KeV in NSCLC between the groups showing negative and moderately positive expression of VEGF (p=0.001, 0.000, and 0.001, respectively) as well as between those showing mildly and moderately positive expression of VEGF (p=0.047, 0.005, and 0.002, respectively). In addition, all of the iodine concentrations, λHU values, and CT values at 40 KeV displayed a significant and positive correlation with the level of VEGF expression (r=0.413, 0.458, and 0.393, respectively, p<0.05). CONCLUSIONS: Quantitative parameters of spectral CT imaging may be helpful for evaluating the status of angiogenesis in NSCLC.

Autologous peripheral blood stem cell transplantation to treat thromboangiitis obliterans: preliminary results.

OBJECTIVE: To investigate the efficiency of autologous peripheral blood stem cell transplantation (APBSCT) to treat severe the lower limbs ischemia caused by thromboangiitis obliterans (TAO). PATIENTS AND METHODS: From April 2007 to December 2014, a total of 64 patients with TAO (80 affected limbs) received APBSCT at our hospital. The treatment effect was evaluated by subjective indicators including pains and cold sensation of the affected limbs, combined with objective indicators including claudication distance, ankle brachial index (ABI), transcutaneous oxygen pressure (TcPO2) and skin temperature. RESULTS: Five patients (with 5 affected limbs) suffered from necrosis below the middle of the leg 4 weeks after transplantation and received amputation. For the remaining 59 patients (75 affected limbs), pain and cold sensation of the affected limbs were improved with varying extent 3 months after transplantation; there were statistically significant differences in pain score and cold sensation score of the affected limbs before and after APBSCT (p<0.05). Claudication distance, ABI, TcPO2 and skin temperature were also improved. Claudication distance increased from 85.69 m ± 43.48 m to 36.5 ± 9.88 mmHg, and the skin temperature of the lower limbs increased from 27.70 °C ± 0.53 °C to 33.49 °C ± 0.60 °C. All four indicators were considerably improved after APBSCT (p<0.05). Arteriography was performed for 75 affected limbs in 59 patients 6 months after transplantation and found that new collateral vessels were formed in the affected limbs. No patients were complicated by retinal hyperplasia, malignant tumors, myocardial infarction and cerebral infarction during the follow-up examinations; no patients underwent symptom aggravation during 9-48 month follow-up (average, 28.5 months). CONCLUSIONS: APBSCT is an easy, safe and reliable treatment for ischemia of lower limbs, especially for those with poor distal arterial outflow tract in the lower limbs that do not permit bridging.

HLA-B*35:168, a novel HLA allele identified in a Chinese platelet donor.

HLA-B*35:168 has one nucleotide change from HLA-B*35:01:01:01 where 20 P is changed to R.

Early evaluation of targeted therapy effectiveness in non-small cell lung cancer by dynamic contrast-enhanced CT.

PURPOSE: To study the feasibility and clinical value of dynamic contrast-enhanced (DCE) computed tomography (CT) for early evaluation of targeted therapy efficacy in non-small cell lung cancer (NSCLC). METHODS: We measured tumor diameter, peak height (PH), time to peak (TP), tumor mass-aortic peak height ratio (M/A), and blood perfusion (BP) in 20 patients with advanced NSCLC using DCE-CT before and 7 days after treatment. Therapy efficacy was assessed with conventional CT 4-6 weeks post-treatment. RESULTS: Patients were grouped into those with partial response (PR), stable disease (SD), and progressive disease (PD) according to the therapy efficacy assessment at 4-6 weeks post-treatment. The PR group primary tumor diameter (P = 0.0007) and BP (P = 0.0225) were reduced at 7 days post-treatment; the SD group DCE-CT value changes were not significant. The PD group M/A (P = 0.0443) and BP (P = 0.0268) were increased 7 days post-treatment. The BP decrease group had significantly longer progression-free survival than the BP increase group (median, 54 vs. 6 weeks). CONCLUSION: DCE-CT can evaluate targeted therapy efficacy at 7 days post-treatment. Decreased primary tumor diameter and BP indicate tumor sensitivity to therapy; increased BP with unchanged tumor diameter suggests the tumor is not sensitive to therapy. Reduced BP suggests treatment effectiveness.

The prevalence of mutations in the major hydrophilic region of the surface antigen of hepatitis B virus varies with subgenotype.

Mutations in the major hydrophilic region (MHR) of the surface antigen of hepatitis B virus (HBV) may result in vaccine escape, failure of immunotherapy and antiviral resistance. These mutants may be transmitted and constitute a public health threat. We aimed to determine the prevalence of MHR mutations of HBV in areas of high endemicity in Guangxi, China. HBV surface gene was analysed from 278 HBsAg-positive asymptomatic individuals recruited from Guangxi using cluster sampling. Three genotypes, B, C and I, were identified. The overall prevalence of MHR mutations is 17·6%. The prevalence of MHR mutations in genotype B (15·1%) is not significantly different from that in genotype C (16·4%). However, the prevalence in subgenotype C5 (31·1%) is significantly higher than in subgenotype C2 (13·0%) (χ 2 = 6·997, P < 0·05). The prevalence of escape mutations and overlapping polymerase substitutions in subgenotype C5 is significantly higher than in subgenotypes B2 and C2. In total, 7·9% of MHR mutants are escape mutations and 72·1% of MHR mutations produced amino-acid changes in the overlapping polymerase, including resistance mutations to entecavir. Our results suggest that the prevalence of MHR mutations varies with subgenotype. The prevalence of escape mutations and polymerase mutations may be associated with subgenotype.

Nimotuzumab with cisplatin or fluorouracil on human esophageal squamous cell carcinoma EC1 cells.

OBJECTIVE: To investigate the effects of nimotuzumab (h-R3) with cisplatin (DDP) or fluorouracil (5-FU) on human esophageal squamous cell carcinoma (ESCC) EC1 cells. MATERIALS AND METHODS: The assignment included blank control, h-R3 alone, DDP alone, 5-FU alone, h-R3 combined with DDP, and h-R3 combined with 5-FU. The cell proliferation in each group was measured by MMT method 48 h post dose. The effect on the cell cycle was determined by flow cytometry, and the effect on cell apoptosis was determined by flow cytometry and TUNEL test 48 h post dose. RESULTS: The inhibitory effect of h-R3 on the proliferation of EC1 cells was weak. The maximum inhibition rate was 10.10 ± 0.58% 48 h post dose, and the difference in the inhibition rate between the h-R3 with chemotherapeutic agents and the chemotherapeutic agent alone was not statistically significant (p > 0.05). Flow cytometry demonstrated no obvious change in the EC1 cells after h-R3 treatment (p > 0.05). Flow cytometry and TUNEL test demonstrated that the difference in the apoptosis rate between h-R3 combined with chemotherapeutic agents and blank control was not statistically significant (p > 0.05). CONCLUSIONS: h-R3 had no significant effect on human ESCC EC1 cells in vitro, with or without the combination of chemotherapeutic agents.

A meta-analysis of limb-salvage versus amputation in the treatment of patients with Enneking‡U pathologic fracture osteosarcoma.

INTRODUCTION: The aim of this meta-analysis was to further explore whether the relapse, 5-year survival and metastasis the same or not between limb-salvage and amputation in the treatment of patients with limited stage Enneking II pathologic fracture osteosarcoma. MATERIALS AND METHODS: An electronic search of the Medline, EMBASE and CNKI was done on October 2014. The clinical studies about amputation or limb-salvage surgery in the treatment of patients with limited stage Enneking II pathologic fracture osteosarcoma were searched and reviewed. The effect size of relapse, 5-year survival and metastasis between the amputation and limb-salvage surgery were pooled by stata11.0 software (Stata Corporation, College Station, TX, USA, http://www.stata.com;) using random or fixed effect model. The funnel plot and Egger's line regression test were used for evaluation of publication bias. RESULTS: A total of 89 studies were identified and seven articles with 200 cases in the limb-salvage surgery group and 84 subjects in the amputation group were finally included in the meta-analysis. The pooled data indicated that no statistical different of risk for developing relapse between limb-salvage and amputation was found relative risk (RR) =1.40, 95% confidence interval (CI): 0.71-2.79, (P = 0.33). The 5-year survival rate of patients underwent limb-salvage surgery was smaller than patients received amputation RR = 1.86, 95%CI: 1.19-2.89, (P = 0.01); the metastasis rate of patients underwent limb-salvage surgery was significant decreased compared with patients received amputation RR = 0.56, 95% CI: 0.34-0.94, (P = 0.03). No publication bias was existed in this meta-analysis. CONCLUSION: Limb-salvage surgery does not increased the risk of relapse compared with amputation in the treatment of patients with limited stage Enneking II pathologic fracture osteosarcoma.

Relationship between RFC gene expression and intracellular drug concentration in methotrexate-resistant osteosarcoma cells.

Osteosarcoma is a primary malignant tumor in adolescents, associated with high mortality and morbidity. The high-dose methotrexate (MTX) chemotherapy used to treat this disease may induce primary or secondary drug resistance, resulting in a reduced effect of comprehensive treatment. In this study, the relationship between reduced folate carrier (RFC) gene expression and intracellular drug concentration in MTX-resistant osteosarcoma cells (Saos-2) was investigated. MTX-resistant human osteosarcoma cells (Saos-2/MTX2.2, Saos-2/MTX4.4) were prepared. The sensitivities of Saos-2 (primary cells), Saos-2/MTX2.2, and Saos-2/MTX4.4 cells to MTX, diamminedichloroplatinum (DDP), ifosfamide (IFO), epirubicine (EPI), adriamycin (ADM), theprubicin (THP), and paclitaxel (PTX) were detected by MTT. The median inhibitory concentration (IC50) and resistance index were measured. Semi-quantitative RT-PCR was used to evaluate the expression of RFC gene in cells. The intracellular (3)H-MTX concentration was determined. Results showed that IC50 of Saos-2/MTX2.2 and Saos-2/MTX4.4 was 4.87 and 12.73 times that of Saos-2, respectively. Both Saos-2/MTX2.2 and Saos-2/MTX4.4 had resistance to IFO, ADM, EPI, THP, and PTX, but not DDP. Compared to Saos-2/MTX2.2 and Saos-2/MTX4.4, the expression of RFC mRNA in Saos-2 was significantly higher. The intracellular (3)H-MTX concentration reached a peak at 50 min. After 70 min, the concentration was maintained at a plateau. During this phase, the (3)H-MTX concentration in Saos-2 cells was 2.15 times higher than the concentration in Saos-2/MTX4.4 cells. The reduced RFC mRNA expression in PTX-resistant osteosarcoma cells may be related to the decrease in intracellular (3)H-MTX concentration.

Management of Meloidogyne incognita on tomato with endophytic bacteria and fresh residue of Wasabia japonica.

AIMS: To characterize the nematicidal endophytic bacteria (NEB) of Wasabia japonica (wasabi) and evaluated the control efficacies of promising NEB as well as fresh wasabi residue (FWR) against Meloidogyne incognita on tomato. METHODS AND RESULTS: By in vitro bioassay, 53 NEB strains showing nematicidal efficacies of >50% against J2 of M. incognita were isolated from wasabi. Basing on 16S rRNA gene sequences, these NEB were identified into 18 species of 11 genera. In greenhouse, incorporation of selected NEB culture or FWR into potted soil significantly reduced infection of M. incognita on tomato. Treating tomatoes with either FWR or NEB of Raoultella terrigena RN16 and Pseudomonas reinekei SN21 in the field yielded excellent control efficacies against M. incognita, especially the combinations of FWR with either R. terrigena RN16 or Ps. reinekei SN21 at doses of 50 g plus 100 ml per plant or more. CONCLUSIONS: The results established that R. terrigena RN16 and Ps. reinekei SN21 applied separately or combined with FWR have the potential to provide bioprotection agents against M. incognita. SIGNIFICANCE AND IMPACT OF THE STUDY: This study provides novel way for disease management using combination of endophyte and host residue.

Effect of solid boundaries on swimming dynamics of microorganisms in a viscoelastic fluid.

We numerically study the effect of solid boundaries on the swimming behavior of a motile microorganism in viscoelastic media. Understanding the swimmer-wall hydrodynamic interactions is crucial to elucidate the adhesion of bacterial cells to nearby substrates which is precursor to the formation of the microbial biofilms. The microorganism is simulated using a squirmer model that captures the major swimming mechanisms of potential, extensile, and contractile types of swimmers, while neglecting the biological complexities. A Giesekus constitutive equation is utilized to describe both viscoelasticity and shear-thinning behavior of the background fluid. We found that the viscoelasticity strongly affects the near-wall motion of a squirmer by generating an opposing polymeric torque which impedes the rotation of the swimmer away from the wall. In particular, the time a neutral squirmer spends at the close proximity of the wall is shown to increase with polymer relaxation time and reaches a maximum at Weissenberg number of unity. The shear-thinning effect is found to weaken the solvent stress and therefore, increases the swimmer-wall contact time. For a puller swimmer, the polymer stretching mainly occurs around its lateral sides, leading to reduced elastic resistance against its locomotion. The neutral and puller swimmers eventually escape the wall attraction effect due to a releasing force generated by the Newtonian viscous stress. In contrast, the pusher is found to be perpetually trapped near the wall as a result of the formation of a highly stretched region behind its body. It is shown that the shear-thinning property of the fluid weakens the wall-trapping effect for the pusher squirmer.