Interferon-gamma and tumor necrosis factor-alpha synergistically enhance the immunosuppressive capacity of human umbilical-cord-derived mesenchymal stem cells by increasing PD-L1 expression

BACKGROUND

The immunosuppressive capacity of mesenchymal stem cells (MSCs) is dependent on the "license" of several proinflammatory factors to express immunosuppressive factors such as programmed cell death 1 ligand 1 (PD-L1), which determines the clinical therapeutic efficacy of MSCs for inflammatory or immune diseases. In MSCs, interferon-gamma (IFN-γ) is a key inducer of PD-L1 expression, which is synergistically enhanced by tumor necrosis factor-alpha (TNF-α); however, the underlying mechanism is unclear.

AIM

To reveal the mechanism of pretreated MSCs express high PD-L1 and explore the application of pretreated MSCs in ulcerative colitis.

METHODS

We assessed PD-L1 expression in human umbilical-cord-derived MSCs (hUC-MSCs) induced by IFN-γ and TNF-α, alone or in combination. Additionally, we performed signal pathway inhibitor experiments as well as RNA interference experiments to elucidate the molecular mechanism by which IFN-γ alone or in combination with TNF-α induces PD-L1 expression. Moreover, we used luciferase reporter gene experiments to verify the binding sites of the transcription factors of each signal transduction pathway to the targeted gene promoters. Finally, we evaluated the immunosuppressive capacity of hUC-MSCs treated with IFN-γ and TNF-α in both an in vitro mixed lymphocyte culture assay, and in vivo in mice with dextran sulfate sodium-induced acute colitis.

RESULTS

Our results suggest that IFN-γ induction alone upregulates PD-L1 expression in hUC-MSCs while TNF-α alone does not, and that the co-induction of IFN-γ and TNF-α promotes higher expression of PD-L1. IFN-γ induces hUC-MSCs to express PD-L1, in which IFN-γ activates the JAK/STAT1 signaling pathway, up-regulates the expression of the interferon regulatory factor 1 (IRF1) transcription factor, promotes the binding of IRF1 and the PD-L1 gene promoter, and finally promotes PD-L1 mRNA. Although TNF-α alone did not induce PD-L1 expression in hUC-MSCs, the addition of TNF-α significantly enhanced IFN-γ-induced JAK/STAT1/IRF1 activation. TNF-α up-regulated IFN-γ receptor expression through activation of the nuclear factor kappa-B signaling pathway, which significantly enhanced IFN-γ signaling. Finally, co-induced hUC-MSCs have a stronger inhibitory effect on lymphocyte proliferation, and significantly ameliorate weight loss, mucosal damage, inflammatory cell infiltration, and up-regulation of inflammatory factors in colitis mice.

CONCLUSION

Overall, our results suggest that IFN-γ and TNF-α enhance both the immunosuppressive ability of hUC-MSCs and their efficacy in ulcerative colitis by synergistically inducing high expression of PD-L1.

[Cross-sectional study of low anterior resection syndrome in patients who have survived more than 5 years after sphincter-preserving surgery for rectal cancer]

Objective: In this study, we aimed to investigate the prevalence of low anterior resection syndrome (LARS) in patients who had survived for more than 5 years after sphincter-preserving surgery for rectal cancer and to analyze its relationship with postoperative time. Methods: This was a single-center, retrospective, cross-sectional study. The study cohort comprised patients who had survived for at least 5 years (60 months) after undergoing sphincter- preserving radical resection of pathologically diagnosed rectal adenocarcinoma within 15 cm of the anal verge in the Department of Gastrointestinal Surgery, Peking University People's Hospital from January 2005 to May 2016. Patients who had undergone local resection, had permanent stomas, recurrent intestinal infection, local recurrence, history of previous anorectal surgery, or long- term preoperative defecation disorders were excluded. A LARS questionnaire was administered by telephone interview, points being allocated for incontinence for flatus (0-7 points), incontinence for liquid stools (0-3 points), frequency of bowel movements (0-5 points), clustering of stools (0-11 points), and urgency (0-16 points). The patients were allocated to three groups based on these scores: no LARS (0-20 points), minor LARS (21-29 points), and major LARS (30-42 points). The prevalence of LARS and major LARS in patients who had survived more than 5 years after surgery, correlation between postoperative time and LARS score, and whether postoperative time was a risk factor for major LARS and LARS symptoms were analyzed. Results: The median follow-up time of the 160 patients who completed the telephone interview was 97 (60-193) months; 81 (50.6%) of them had LARS, comprising 34 (21.3%) with minor LARS and 47 (29.4%) with major LARS. Spearman correlation analysis showed no significant correlation between LARS score and postoperative time (correlation coefficient α=-0.016, P=0.832). Multivariate analysis identified anastomotic height (RR=0.850, P=0.022) and radiotherapy (RR=5.760, P<0.001) as independent risk factors for major LARS; whereas the postoperative time was not a significant risk factor (RR=1.003, P=0.598). The postoperative time was also not associated with LARS score rank and frequency of bowel movements, clustering, or urgency (P>0.05). However, the rates of incontinence for flatus (3/31, P=0.003) and incontinence for liquid stools (8/31, P=0.005) were lower in patients who had survived more than 10 years after surgery. Conclusions: Patients with rectal cancer who have survived more than 5 years after sphincter-preserving surgery still have a high prevalence of LARS. We found no evidence of major LARS symptoms resolving over time.

Adjuvant icotinib versus observation in patients with completely resected EGFR-mutated stage IB NSCLC (GASTO1003, CORIN): a randomised, open-label, phase 2 trial

BACKGROUND

This phase 2 trial aimed to compare adjuvant icotinib with observation in patients with epidermal growth factor receptor (EGFR) mutation-positive resected stage IB non-small cell lung cancer (NSCLC).

METHODS

We performed a randomised, open-label, phase 2 trial from May 1, 2015 to December 29, 2020 at Sun Yat-sen University Cancer Center in China. Patients with completely resected, EGFR-mutant, stage IB (the 7th edition of TNM staging) NSCLC without adjuvant chemotherapy were randomised (1:1) to receive adjuvant therapy with icotinib (125 mg, three times daily) for 12 months or to undergo observation until disease progression or intolerable toxicity occurred. The primary endpoint was 3-year disease-free survival (DFS). CORIN (GASTO1003) was registered with Clinicaltrials.gov, with the number NCT02264210.

FINDINGS

A total of 128 patients were randomised, with 63 patients in the icotinib group and 65 patients in the observation group. The median duration of follow-up was 39.9 months. The three-year DFS was significantly higher in the icotinib group (96.1%, 95% confidence interval [CI], 91.3-99.9) than in the observation group (84.0%, 95% CI, 75.1-92.9; P = 0.041). The DFS was significantly longer in the icotinib group than in the observation group, with a hazard ratio (HR) of 0.23 (95% CI, 0.07-0.81; P = 0.013). The OS data were immature, with three deaths in the observation arm. In the icotinib group, adverse events (AEs) of any grade were reported in 49 patients (77.8%), and grade 3 or greater AEs occurred in four patients (6.3%). No treatment-related deaths occurred.

INTERPRETATION

Our findings suggested that adjuvant icotinib improved the 3-year DFS in patients with completely resected EGFR-mutated stage IB NSCLC with a manageable safety profile.

FUNDING

This study was sponsored by Betta Pharmaceutical Co., Ltd.

[Anastomotic vessels between superior mesenteric artery and inferior mesenteric artery: controversies and advances]

The anastomotic vessels between the superior mesenteric artery and the inferior mesenteric artery are vital to maintain the blood supply of the anastomosis and residual colon after colectomy. However, current studies of anastomotic vessels are facing four major obstacles: confusing nomenclature, large variability in data, diversification of research methods and incomplete information records. The existence of marginal artery has been widely proved, and its significance for blood supply is well recognized by relevant studies. In contrast, the Riolan's arch, whose connotations constantly changed over history, can not refer to a specific structure accurately. Researchers should abolish the controversial names such as Riolan's arch, select appropriate research methods and record the anastomotic vessels in detail, so as to improve the comparability between different results. The study of anastomotic vessels can help us to identify potential vascular disease, select the appropriate surgical approach, and provide appropriate treatment of the vessels in the operating area, so as to provide a theoretical foundation and practical basis for fine surgical maneuvers.

[Research progress of sexual dysfunction following rectal cancer surgery]

Sexual dysfunction with the incidence of 5%-90% is a common postoperative complication of rectal cancer and the ratio of men and women is similar. Sexual function is innervated by the abdominal-pelvic autonomic nerve. Different sexual dysfunctions can be caused by different parts and degrees of injury in autonomic nerve during operations of rectal cancer. With the development of pelvic autonomic nerves preservation in rectal cancer radical resection, postoperative sexual function can be protected. There may be many factors increasing the incidence of postoperative sexual dysfunction in rectal cancer, such as postoperative psychological factors, stoma, abdominal-perineal resection and radiotherapy. The effects of laparoscopic surgery, robotic surgery, transanal total mesorectal excision and lateral lymph node dissection on postoperative sexual function remain controversial. Based on the multidisciplinary cooperation model, attention should be paid to psychological intervention of patients and their partners. In clinical practice, for male using phosphodiesterase-5 inhibitors, vacuum erectile devices, injection of vasodilators through the penis or urethra, and for female local application of estrogen and lubricants in the vagina are effective treatment for postoperative sexual dysfunction of rectal cancer. In addition, stem cell therapy has a promising prospect for sexual dysfunction.

[Pros and cons of perioperative therapy in the protection of organ function in rectal cancer]

The goal of rectal cancer treatment should be to better protect organ function and improve patients' quality of life on the basis of ensuring radical resection. The current evidence has proved the superiority of perioperative chemoradiotherapy in reducing local recurrence and improving long-term survival. From the perspective of organ function protection, however, perioperative chemoradiotherapy has both disadvantages and advantages. Despite the great help in improving long-term outcomes, adverse reactions of chemoradiotherapy can aggravate defecation, urination and sexual dysfunction. Also, for patients with significant or complete remission, if the treatment strategy of local resection or close follow-up is selected, organ function can be preserved to the greatest extent. The key to the choice of treatment is to evaluate preoperatively whether pathological complete response is achieved. It should be kept in mind that preserving organ itself is not the same as protecting organ function. For patients who need perioperative chemoradiation, the optimal treatment methods should be chosen based on the patient's condition. Surgeons should fully evaluate organ function before operation, select the appropriate treatment strategy, pay special attention to the protection of important organs and nerves during surgeries, and carry out close postoperative follow-up and organ function rehabilitation as soon as possible, so as to reduce the incidence of dysfunction and the impact on the quality of life.

[Clinicopathological features and prognosis in patients with presacral recurrent rectal cancer]

Objective: To investigate the clinicopathological features and prognostic factors in patients with presacral recurrent rectal cancer (PRRC). Methods: PRRC was defined as recurrence of rectal cancer after radical surgery involving posteriorly the presacral soft tissue, the sacrum/coccyx, and/or sacral nerve root. The diagnosis is confirmed with clinical symptoms (pain of pelvis/back/lower limb, bloody stools, increased frequency of defecation, and abnormal secretions), physical examination of perineal or pelvic masses, radiological findings, colonoscopy with histopathological biopsy, and the evaluation by multi-disciplinary team (MDT). Inclusion criteria: (1) primary rectal cancer undergoing radical surgery without distant metastasis; (2) PRRC was diagnosed; (3) complete inpatient, outpatient and follow-up data. According to the above criteria, clinical data of 72 patients with PRRC in Peking University People's Hospital from January 2008 to December 2017 were retrospectively analyzed. The clinicopathological features and follow-up data were summarized. Cox proportional hazard models was used to analyze the prognostic factors of PRRC. Results: Among 72 patients, 45 were male and 27 were female with a male-to-female ratio of 1.7:1.0. The median age at recurrence was 58 (34 to 83) years and the median interval from surgery to recurrence was 2.0 (0.2 to 17.0) years. The main symptom was pain in 48.6% (35/72) of patients. In addition, gastrointestinal symptoms were found in 25.0% (18/72) of patients. The presacral recurrent sites were presacral fascia in 36 (50.0%) patients, lower sacrum (S3~S5 or coccyx) in 25 (34.7%) patients, and higher sacrum (S1~S2) in 11 (15.3%) patients. Forty-seven (65.3%) patients underwent radical surgery (abdominal resection, abdominoperineal resection, sacrectomy, abdominosacral resection), 12 (16.7%) underwent non-radical surgery (colostomy, cytoreductive surgery), and 13 (18.1%) did not undergo any surgery but only receive palliative chemoradiotherapy and nutritional support treatment. Thirty-three (45.8%) patients received radiotherapy and/or chemotherapy (oxaliplatin, 5-fluorouracil, capecitabine, irinotecan, etc.). All the patients received follow-up, and the median follow-up time was 19 (2 to 72) months. The median overall survival time was 14 (1 to 65) months. The 1- and 3-year overall survival rates were 67.1% and 32.0%, respectively. Univariate analysis showed that age at recurrence (P=0.031) and radical resection (P<0.001) were associated with prognosis. Multivariate analysis demonstrated that radical resection was independent factor of good prognosis (RR=0.140, 95%CI: 0.061-0.322, P<0.001). Conclusions: Patients tend to develop presacral recurrent rectal cancer within 2 years after primary surgery. The main symptom is pain. Patients undergoing radical resection have a relatively good prognosis.

[Comparison of clinical efficacy among different surgical methods for presacral recurrent rectal cancer]

Objective: To investigate the efficacy and prognosis of three surgical methods for presacral recurrent rectal cancer (PRRC). Methods: A retrospective cohort study was carried out. Case inclusion criteria: (1) primary rectal cancer without distant metastasis and undergoing radical surgery; (2) patients undergoing radical surgery after the diagnosis of PRRC; (3) complete inpatient, outpatient and follow-up data. Clinical data of 47 patients meeting the above criteria who underwent operation at the Department of Gastrointestinal Surgery, The Peking University People's Hospital from January 2008 to December 2017 were reviewed and analyzed retrospectively. Of the 47 patients, 31 were male and 16 were female; the mean age was 57 years old; 9 (19.1%) were low differentiation or signet ring cell carcinoma, 38 (80.9%) were medium differentiation; 19 (40.4%) received neoadjuvant therapy. According to operative procedure, 22 patients were in the abdominal/abdominoperineal resection group, 15 in the sacrectomy group and 10 in the abdominosacral resection group. The operative data, postoperative data and prognosis were compared among the three groups. Survival curve was conducted using the Kaplan-Meier method, and log-rank test was used to compare survival difference among three groups. Results: There were no significant differences in baseline data among three groups (all P>0.05). All the 47 patients completed the radical resection successfully. The mean operation time was (4.7±2.1) hours, the median intraoperative blood loss was 600 ml, and the median postoperative hospitalization time was 17 days. Fifteen cases (31.9%) had perioperative complications, of which 3 cases were grade III-IV. There was no perioperative death. The mean operative time was (7.4±1.6) hours in the abdominosacral resection group, (4.9±1.6) hours in the abdominal/abdominoperineal resection group, and (3.0±1.1) hours in the sacroectomy group, with a significant difference (F=25.071, P<0.001). There were no significant differences in intraoperative blood loss, postoperative hospitalization days and perioperative complications among the three groups (all P>0.05). The median follow-up period of all the patients was 24 months, 12 cases (25.5%) developed postoperative dysfunction. The incidence of postoperative dysfunction in the abdominosacral resection group was 5/10, which was higher than 4/15 in the sacrectomy group and 3/22 (13.6%) in the abdominoperineal resection group with statistically significant difference (χ(2)=9.307, P=0.010). The 1-year and 3-year overall survival rates were 86.1% and 40.2% respectively. The 1-year overall survival rates were 86.0%, 86.7% and 83.3%, and the 3-year overall survival rates were 33.2%, 40.0% and 62.5% in the abdominal/abdominoperineal resection group, sacrectomy group and abdominosacral resection group, respectively, whose difference was not statistically significant (χ(2)=0.222, P=0.895). Conclusions: Abdominal/abdominoperineal resection, sacrectomy and abdominosacral resection are all effective for PRRC. Intraoperative function protection should be concerned for patients undergoing abdominosacral resection.

[Controversy and consideration of high and low ligation of inferior mesenteric artery in radical resection of rectal cancer]

Radical resection is one of the most important treatment for rectal cancer, which requires not only removal of adequate bowel and mesorectum around the tumor, but also thorough lymphadenectomy. Besides, postoperative complications are surgeons' concerns as well. According to different ways to manage inferior mesenteric artery, procedures could be divided into two groups: inferior mesenteric artery (IMA) high ligation and low ligation, which lead to various outcomes of the extent of lymph nodes dissection, survival, preservation of intestinal blood supply, incidence of anastomotic leakage, and postoperative functions including defecation function, urinary function and sexual function. Author believes that for those patients with clinical stage T1, low ligation and D2 lymph nodes dissection could be considered. However, for patients with locally advanced carcinomas (clinical stage T2+or N+), especially suspicious metastasis of lymph nodes around IMA root, high ligation and D3 lymph node dissection is suggested to ensure en bloc resection. As for those patients with high risks for compromised intestinal blood supply, preservation of left colic artery plus D3 lymph nodes dissection might be a feasible way. Intraoperative indocyanine green fluorescent imaging might play a role in quality control of lymphadenectomy.

[Comparative study of functional prognosis of transanal total mesorectal excision and conventional total mesorectal excision based on propensity score matching]

Objective: To compare the postoperative functional prognosis of transanal mesorectal excision (taTME) and conventional total mesorectal excision (TME) in rectal cancer. Methods: Totally 49 patients underwent taTME and 478 patients underwent conventional TME at Department of Gastroenterological Surgery, Peking University People's Hospital from January 2015 to December 2019 were retrospectively collected. Propensity score matching method was used to perform 1 versus 1 matching between the taTME and conventional TME groups, and 36 pairs of patients were successfully matched. After matching, the median age of patients in taTME group and conventional TME group was 60.5 (16.0) years and 60.5 (13.0) years (M(Q(R))), respectively, and the proportion of male patients was 66.7% (24/36) and 55.6% (20/36) , respectively. EORTC QLQ-C30 scale was used to assess quality of life, low anterior resection syndrome (LARS) scale and Wexner constipation score were used to evaluate anal function, international prostate symptom score (IPSS) was used to evaluate urinary function,international index of erectile function (IIEF) -5 and female sexual function index (FSFI) score were used to evaluate male and female sexual function, respectively, and generalized anxiety disorder (GAD-7) and patient health questionnaire (PHQ-9) scale were used to evaluate psych function. The t test, Mann-Whitney U test, χ(2) test, and Fisher exact test were used for comparison between groups, and Wilcoxon rank sum test or McNemar test was used for comparison between paired data. Results: There were no significant differences in surgery time, postoperative hospital stays, conversion rate, morbidity rate, surgery cost, and numbers of lymph node yield between the two groups (all P>0.05). Compared with the conventional TME group, the intraoperative blood loss in the taTME group was significantly higher (100 (100) ml vs. 80 (50) ml, U=424.5, P=0.010), the prophylactic stoma rate was significantly higher (96.9%(31/36) vs. 63.6%(21/36), χ(2)=11.218, P<0.01), the total hospitalization cost was significantly lower (74 297.7 (16 746.4) CNY vs. 91 781.3 (26 228.4) CNY, U=413.0, P=0.008). There were no significant differences in anal and urinary function between the two groups (LARS scalescore: Z=-0.513, P=0.608, Wexner constipation score: Z=-0.992, P=0.321, IPSS: Z=-1.807, P=0.071). In terms of psych function, significant difference in GAD-7 scale was seen between the two groups (Z=-2.311, P=0.021), patients with generalized anxiety disorder accounting for 26.7% (8/30) and 46.9% (15/32), respectively. Conclusions: Compared with conventional TME surgery, taTME has a significantly increased blood loss and prophylactic stoma rate. There are no significant difference in the incidence of postoperative anal, urinary, and sexual dysfunction between taTME and conventinal TME. taTME can alleviate the financial burden and general anxiety disorder to a certain extent.

[Application of indocyanine green fluorescence imaging in colorectal cancer surgery]

Indocyanine green (ICG) fluorescence imaging has been widely used in surgery. In colorectal surgery specifically, more and more studies have shown that intraoperative fluorescence imaging is a safe and feasible method to assess anastomotic perfusion, and its use may decrease the incidence of anastomotic leakage. Meanwhile, indocyanine green can also be used to mark the location of lesion, identify sentinel lymph nodes, protect the ureter, and so on. It can also provide detection and guidance in the operation of peritoneal metastasis and liver metastasis of colorectal cancer. The application of indocyanine green fluorescence imaging can offer great value for surgery through improving the accuracy and outcomes of oncological resections. According to existing studies, we are still at an early application stage of indocyanine green fluorescence imaging technology in colorectal surgery. Lacking prospective randomized controlled studies, neither standards nor guidelines for injection dosage, site and observation period are satisfactory. Therefore, deep researches and establishment of standardized operational procedure are required to enhance the safety and accuracy of tumor resection and improve outcomes.

[Detection of preoperative chemoradiotherapy sensitivity molecular characteristics of rectal cancer by transcriptome second generation sequencing]

OBJECTIVE

To detect the preoperative chemoradiotherapy sensitivity molecular characteristics of rectal cancer by transcriptome second generation sequencing.

METHODS

The clinicopathological data of 30 patients with locally advanced rectal cancer were collected prospectively, including 9 indicators (general conditions, imaging data before radiotherapy and chemotherapy, pathological data of biopsy before radiotherapy and chemotherapy, and tumor differentiation degree, etc.), in order to analyze the correlation between them and tumor regression grading (TRG) after radiotherapy and chemotherapy for rectal cancer. At the same time, frozen specimens of colonoscopy biopsy before neoadjuvant therapy were collected from these 30 patients, and transcriptome second-generation sequencing was performed for bioinformatics analysis to screen out the genes that might drive the radio chemotherapy sensitivity of rectal cancer.

RESULTS

Among the 30 patients with rectal cancer, 9 had complete pathological remission, 12 had partial remission, and 9 had poor remission. The degree of pathological TRG remission after radiotherapy and chemotherapy for rectal cancer was negatively correlated with the preoperative MRI T stage (P=0.046), and positively correlated with preoperative MRI rectal cancer extravascular invasion (EMVI) (P=0.003). Transcriptome second-generation sequencing of the obtained 217 transcripts (P<0.05) for signal pathway enrichment analysis, and multiple cell signal transduction pathways related to antigen presentation could be found. The high expression of HSPA1A, HSPA1B and EXOSC2 was positively correlated with postoperative pathological remission (P<0.05). The high expression of DNMBP, WASH8P, FAM57A, and SGSM2 was positively correlated with postoperative pathological remission (P<0.05).

CONCLUSION

Preoperative NMR detection of extra-tumoral vascular invasion (EMVI-positive) in patients with rectal cancer was significantly better than that of EMVI-negative patients after chemoradiotherapy. Patients with high expressions of HSPA1A, HSPA1B and EXOSC2 had poor postoperative pathological remission, while patients with high expressions of genes, such as DMNMB, WASH8P, FAM57A, and SGSM2 had good postoperative pathological remission. Based on the molecular characteristics of rectal cancer radiotherapy and chemotherapy, attempts to block or enhance the molecular pathways associated with chemosensitivity of rectal cancer, are to be made to further explore new candidate therapeutic targets that can increase the sensitivity of radiotherapy and chemotherapy for rectal cancer.

[Evaluation of health effect among occupational population exposed to nano-titanium dioxide: a cross-sectional study]

Objective: To characterize the health effects of nano-titanium dioxide exposure in an occupational cohort. Methods: Eighty-five male employees of a nano-titanium dioxide manufacturing enterprise in Shandong Province were evaluated in September 2014. Forty-four were exposed to nano-titanium dioxide (exposure group), and 41 were not exposed to nano-titanium dioxide (control group). We collected employees' basic information, smoking and drinking history, previous medical history, family history, and occupational history. Differences in blood pressure, hematological parameters, and blood biochemistry between the two groups were analyzed and compared. Multiple linear regression analysis was used to investigate the effect of nano-titanium dioxide exposure on blood pressure, hematological parameters, and blood biochemistry indices after controlling for age, smoking, drinking, and body mass index (BMI). Twenty-five employees from the exposure group and 25 employees from the control group were selected at random for measurement of genetic damage by cytokinesis-block micronucleus assay. Poisson regression analysis was used to investigate the effect of nano-titanium dioxide exposure on micronucleus frequency or micronucleus cell frequency after controlling for age, smoking, drinking, and BMI. Results: The median (P₂₅-P₇₅) surface area concentration of particles deposited in the tracheobronchial region, the surface area concentration of particles deposited in the alveolar region, and particle number concentration in the exposure group were 35.35(24.31-57.42) μ m²/cm³, 173.09(116.27-270.72) μ m²/cm³, and 40 244.00 (17 803.50-78 679.00) /cm³, respectively. These values were significantly higher than those in the control group 33.90 (27.44-43.29) μm²/cm³, 150.50(125.82-192.87)μm²/cm³, and 18 721.00 (12 721.00-51 898.50)/cm³, respectively. Z values were 15.47, 15.96, and 14.54, respectively (P<0.001 for all three values). Multiple linear regression analysis showed that exposure to nano-titanium dioxide contributed most to the alteration of mean corpuscular hemoglobin concentration, creatinine, and LDL-C, with standardized regression coefficients of 0.23, -0.51, and 0.30, respectively (P<0.05 for all three values), after adjusting for age, smoking, drinking, and BMI. There were no significant differences in micronucleus frequency and micronucleus cell frequency between the exposure group (3.00‰ (1.50‰-5.00‰) and 3.00‰ (2.00‰-4.00‰), respectively) and control group (2.00‰ (1.00‰-4.50‰) and 2.00‰ (1.00‰-4.00‰), respectively); P>0.05 for all comparisons. Poisson regression analysis showed that after adjusting for age, smoking, drinking, and BMI, there was still no statistically significant correlation between nano-titanium dioxide exposure and micronucleus frequency (OR=1.11, 95% CI: 0.81-1.54) or micronucleus cell frequency (OR=1.07, 95% CI: 0.75-1.51); P>0.05 for all comparisons. Conclusion: Nano-titanium dioxide particles exerted some health effects on the occupationally-exposed cohort, whose hematological parameters and blood biochemistry were influenced to some degree. However, a potential link between occupational exposure to nano-titanium dioxide and blood pressure or induction of genetic damage or was not found.

A putative molybdate transporter LjMOT1 is required for molybdenum transport in Lotus japonicus

Molybdenum (Mo) is an essential micronutrient that is required for plant growth and development, and it affects the formation of root nodules and nitrogen fixation in legumes. In this study, Lotus japonicus was grown on MS solid media containing 0 nmol l^-1 (-Mo), 103 nmol l^-1 (+Mo) and 1030 nmol l^-1 (10 × Mo) of Mo. The phenotypes of plants growing on the three different media showed no obvious differences after 15 days, but the plants growing on -Mo for 45 days presented typical symptoms of Mo depletion, such as a short taproot, few lateral roots and yellowing leaves. A Mo transporter gene, LjMOT1, was isolated from L. japonicus. It encoded 468 amino acids, including two conserved motifs, and was predicted to locate to chromosome 3 of the L. japonicus genome. A homology comparison indicated that LjMOT1 had high similarities to other MOT1 proteins and was closely related to GmMOT1. Subcellular localization indicated that LjMOT1 is localized to the plasma membrane. qRT-PCR analyses showed that increasing Mo concentrations regulated the relative expression level of LjMOT1. Moreover, the Mo concentration in shoots was positively correlated to the expression of LjMOT1, but there was no such evident correlation in the roots. In addition, changes in the nitrate reductase activity were coincident with changes in the Mo concentration. These results suggest that LjMOT1 may be involved in the transport of Mo and provide a theoretical basis for further understanding of the mechanism of Mo transport in higher plants.

Carcinosarcoma of pancreas with liver metastasis combined with gastrointestinal stromal tumour of the stomach: is there a good prognosis with the complete resection?

We report a carcinosarcoma of the pancreas with liver metastasis combined with gastrointestinal stromal tumour (GIST) of the stomach in a 72-year-old woman who presented with right upper quadrant pain, nausea and vomiting. A radical resection including pancreaticoduodenectomy, left hepatic lobe resection and local resection of the gastric mass was performed. The tumour in the head of pancreas was found to be grossly yellow-white, and it infiltrated the common bile duct and duodenum; the mass of the liver metastasis is solitary. Pathologic examination showed two components separated from each other: one component was a conventional infiltrating pancreatic ductal adenocarcinoma, and the other component showed sarcomatous growth pattern composed of pleomorphic spindle cells. The neoplasm of the stomach was confirmed a low malignant potential GIST by histology and immunohistochemistry. The patient was obliged to be in hospital because of abnormal bowel function; moreover, surveillance CT scans performed at 1.5 months post-operatively showed multiple liver metastasis and recurrence in the tail of pancreas. Unfortunately, the patient died of multiple organ failure at 2 months post-operatively. To our knowledge, this is the first experience report about surgical treatment of carcinosarcoma of pancreas with liver metastasis combined with GIST of the stomach. The patient performed a radical surgery for the metastatic carcinosarcoma even if that could be resected completely did not have a good consequence.

A Schwann cell-seeded intrinsic framework and its satisfactory biocompatibility for a bioartificial nerve graft

To optimize the internal environment of a collagen nerve tube, we designed a Schwann cell-seeded intrinsic framework and its biocompatibility was investigated. We fixed 6-0 polyglactin woven filaments (Vicryl) or polydioxanone monofilaments (PDS) on a silicone ring in a net fashion. It was coated with matrigel and then incubated with cultured newborn or adult Schwann cells. Furthermore, we implanted 1.5-cm-long filament-filled collagen tubes in a rat model. Using a live/dead fluorescent assay and electron microscopy, we found that adherent Schwann cells onto filaments remained viable and oriented longitudinally along filaments. The preliminary in vivo study indicated that a mild inflammatory reaction was present around the tube wall. However, nerve regeneration occurred around and between filaments. We concluded that the arrangement of Schwann cell columns onto filaments was achieved, mimicking Bünger bands. It was shown that the biomaterials did not impede nerve regeneration.

Cellular activity of resident macrophages during Wallerian degeneration

The resident macrophages have been accepted as an important component of the peripheral nervous system as Schwann cells. To elucidate their role during Wallerian degeneration without interference from extrinsic hematogenous macrophages, we designed a culture system to investigate the behavior of resident macrophages in vitro. A total of 75 adult male Lewis rats were used; 2. 5-cm-length sciatic nerve explants were harvested. There were three groups. In the culture groups, the nerve explants were incubated in Dulbecco's modified Eagle's medium (DMEM) only or in DMEM supplemented with 2 microm forskolin and 10 microg/ml pituitary extract (mitogenic medium for Schwann cells). In vivo predegenerated nerves and normal nerves were used as the positive and negative controls, respectively. The observation periods extended to 3 weeks. Hematoxylin and eosin (H&E) stain was employed to estimate overall cell number in nerve explants. Macrophages were labeled with ED1; S-100 immunostaining was used to evaluate the presence of Schwann cells during Wallerian degeneration. Trichrome stain and toluidine blue stain were used to visualize the fate of myelin. In the culture groups, the number of resident macrophages increased continuously, although there were significantly fewer resident macrophages than hematogenous macrophages after 3 days of Wallerian degeneration (P < 0.01). Morphologically, resident macrophages contained densely small ED1-positive granules within their cytoplasm, even at later stages of observation, whereas hematogenous macrophages contained typical large ED1-positive foam vacuoles characteristic of their mature phagocytic ability. The cellular activity of Schwann cells was well preserved in the mitogenic medium; however, myelin removal was not significantly enhanced as compared with the DMEM groups (P > 0.05). The clearance of myelin debris was shown to be incomplete in culture groups as compared with the complete removal of myelin debris in the in vivo groups. Resident macrophages were actively involved in Wallerian degeneration, but their phagocytic and proliferation ability was limited. Schwann cells played an adjunctive role during the removal of myelin debris.

Botulinum toxin treatment of cocontractions after birth-related brachial plexus lesions

The authors studied botulinum toxin type A therapy of severe biceps-triceps cocontractions after nerve regeneration following birth-related brachial plexus lesions. Six children (age, 2 to 4 years) were treated two to three times over a period of 8 to 12 months with 40 mouse units of botulinum toxin at two sites of the triceps muscle. Elbow range of motion improved from 0 to 25 to 50 deg to 0 to 25 to 100 deg (p < 0.05), and muscle force of elbow flexion increased from a mean of Medical Research Council classification 1.7 to 3.7 (p < 0.05). After a 1-year follow-up, there was no clinical recurrence.

Free flap to the arteria peronea magna for lower limb salvage

A 36-year-old woman sustained an amputation of her right leg at the thigh level and a degloving injury of her left foot and ankle region in an accident during a suicide attempt. Primarily, her left foot was covered with a split skin graft, resulting in a soft-tissue defect at the medial malleolus and at the calcaneus bone. Reconstruction was planned with a free latissimus dorsi muscle flap. Preoperative examinations revealed an arteria peronea magna with a hyperplastic peroneal artery solely providing arterial blood supply to the foot. The arteria peronea magna divided into two branches proximal to the upper ankle joint, replacing the dorsal pedis artery and the medial plantar artery. Tibial posterior and tibial anterior arteries were hypoplastic-aplastic. Microvascular end-to-end anastomoses of the flap vessels to the medial branch ("medial plantar artery") of the arteria peronea magna and its concomitant vein at the medial malleolar bone level were successfully performed. The postoperative course was uneventful. Four weeks postoperatively, the patient started walking assisted by a prosthesis on her right thigh stump. This experience demonstrates that even in a case of arteria peronea magna, free flap surgery for lower limb salvage is a reliable and worthwhile method.

Viability of cultured nerve grafts: An assessment of proliferation of Schwann cells and fibroblasts

Previous studies demonstrated that the viability of nerve grafts had a positive effect on nerve regeneration, while the cold storage of nerve grafts obtained few viable cells at the later stage. The purpose of this study was to examine the cellular activities of Schwann cells and fibroblasts in cultured nerve grafts prior to transplantation. 2.5-cm long sciatic nerve grafts were harvested from 75 male Lewis rats. Two different media were utilized to culture the nerve grafts up to 3 weeks: Dulbecco's modified eagle medium (DMEM) only or DMEM supplemented with 2 microM forskolin and 10 microg/ml pituitary exact (mitogen medium for Schwann cells). In vivo predegenerated and normal nerve grafts were used as positive and negative controls, respectively. We employed a 5-bromo-2'-deoxyuridine (BrdU) incorporation method to evaluate the proliferating cells in the cultured nerve grafts. S-100 and vimentin immunostaining were used to estimate the presence of Schwann cells and fibroblasts in all nerve grafts at different intervals. The results showed that the proliferating cells increased progressively under culture conditions. The proliferating cells distributed evenly in small fascicles (average diameter 251 +/- 71.5 microm), whereas they appeared mainly in the margin of large fascicles (average diameter 624 +/- 87.3 microm). The mitogen medium stimulated Schwann cell multiplication more significantly in comparison with DMEM after 3 days of culture (P < 0.01), however, there were fewer fibroblasts present in the mitogen medium than in DMEM after 2 days of culture (P < 0.01). It is suggested that the viability of nerve grafts can be preserved under culture conditions. Furthermore, the cellular activity of the Schwann cells and fibroblasts in nerve grafts can be manipulated in in vitro Wallerian degeneration.

Protective efficacy of major outer membrane protein-specific immunoglobulin A (IgA) and IgG monoclonal antibodies in a murine model of Chlamydia trachomatis genital tract infection

The protective efficacy of immunoglobulin A (IgA) and IgG monoclonal antibodies (MAbs) specific for the major outer membrane protein of Chlamydia trachomatis MoPn was evaluated in a murine genital tract infection model. MAbs were delivered into serum and vaginal secretions of naive mice by using the backpack hybridoma tumor system, and protective efficacy was assessed over the first 8 days following challenge by quantitative determination of chlamydial recovery from cervicovaginal swabs, histopathological evaluation of genital tract tissue, and immunohistochemical detection of chlamydial inclusions. IgA and IgG significantly reduced the incidence of infection following vaginal challenge with 5 50% infectious doses, but such protection was overwhelmed by 10- and 100-fold higher challenge doses. Both MAbs also consistently reduced vaginal shedding from infected animals with all three challenge doses compared with the negative control MAb, although the magnitude of this effect was marginal. Blinded pathological evaluation of genital tract tissues at 8 days postinfection showed a significant reduction in the severity of the inflammatory infiltrate in oviduct tissue of infected IgA- and IgG-treated animals. Immunohistochemical detection of chlamydial inclusions revealed a marked reduction in the chlamydial burden of the oviduct epithelium; this finding is consistent with the reduced pathological changes observed in this tissue. These studies indicate that the presence of IgA or IgG MAbs specific to major outer membrane proteins has a marginal effect in preventing chlamydial colonization and shedding from the genital tract but has a more pronounced effect on ascending chlamydial infection and accompanying upper genital tract pathology.

Fibronectin cell-binding domain triggered transmembrane signal transduction in human monocytes

Fibronectin (Fn) fragments have recently been shown to stimulate tumor necrosis factor (TNF) secretion by human monocytes. In this study, we investigated the signal transduction mechanisms involved in Fn-induced TNF secretion. Treatment of human monocytes with Fn120, a chymotryptic cell-binding fragment of plasma Fn, failed to cause a detectable rise in Ca2+ mobilization. Fn120-induced TNF secretion could be inhibited with Ca2+ channel blockers. The protein kinase C (PKC) inhibitors H-7 and sphingosine inhibited the TNF-inducing activity of Fn120. HA1004 was used as a control for the isoquinoline sulfonamide derivatives and did not change Fn120-induced TNF secretion by monocytes. H-8 inhibited TNF secretion at higher concentrations. A calmodulin-dependent kinase inhibitor, W-7, was found to be effective, with 50% inhibition of Fn120-induced TNF secretion at 5 microM. The activation and translocation of PKC were measured directly. In unstimulated monocytes, approximately 70% of PKC activity was found in the cytosol and 30% in the membrane. Following the stimulation of monocytes with phorbol myristate acetate (100 nM), rapid and sustained translocation of PKC from the cytosol to the membrane was observed. The stimulation of monocytes with Fn120 triggered a rapid translocation of PKC within 2 to 5 min, followed by a return to normal levels within 8 min. These findings support the conclusion that Fn120-induced TNF secretion requires the activation of PKC.