Profiles of central nervous system surgical site infections in endoscopic transnasal surgery exposing the intradural space.

OBJECTIVE: Despite its efficacy and minimal invasiveness, the clean-contaminated nature of endoscopic transnasal surgery (ETS) may be susceptible to central nervous system surgical site infections (CNS-SSIs), especially when involving intradural exposure. However, the profiles of ETS-associated CNS-SSIs are not fully elucidated. METHODS: The institutional ETS cases performed between May 2017 and March 2023 were retrospectively analysed. The incidences of CNS-SSIs were calculated, and their risk factors examined. RESULTS: The incidence of CNS-SSIs was 2.3% (7/305) in the entire cohort and 5.0% (7/140) in ETSs with intradural exposure. All the CNS-SSIs were meningitis and developed following ETS with intradural exposure. The incidences were 0%, 5.6% and 5.8% in ETSs with Esposito grade 1, 2 and 3 intraoperative cerebrospinal fluid leakage, respectively. Among the pre- and intra-operative factors, body mass index (unit odds ratio (OR), 0.62; 95% confidence interval (CI), 0.44-0.89; P<0.01), serum albumin (unit OR, 0.03; 95% CI, 0.0007-0.92; P=0.02), and American Society of Anesthesiologists physical status score (unit OR, 20.7; 95% CI, 1.65-259; P<0.01) were significantly associated with CNS-SSIs. Moreover, postoperative cerebrospinal fluid leakage was also significantly associated with CNS-SSIs (OR, 18.4; 95% CI, 3.55-95.0; P<0.01). CONCLUSIONS: The incidence of ETS-associated CNS-SSIs is acceptably low. Intradural exposure was a prerequisite for CNS-SSIs. Malnutrition and poor comorbidity status should be recognized as important risks for CNS-SSIs in ETS.

Impact of near-infrared fluorescence imaging with indocyanine green on structural sequelae of anastomotic leakage after laparoscopic intersphincteric resection of malignant rectal tumors.

BACKGROUND: Recent studies have indicated the potential benefit of intraoperative near-infrared fluorescence imaging (NIR-FI) with indocyanine green in reducing early anastomotic leakage in colorectal surgery. Nonetheless, whether NIR-FI is effective in reducing structural sequelae of anastomotic leakage (SSAL) remains unclear. The aim of the present study was to investigate the impact of NIR-FI on SSAL after laparoscopic intersphincteric resection (ISR) of malignant rectal tumors. METHODS: This study was a retrospective single-center cohort study. A total of 293 consecutive patients who underwent elective laparoscopic ISR from May 2010 to August 2017 were included. Patients were divided into 2 groups; those who underwent elective laparoscopic ISR with lymphadenectomy for malignant rectal tumors using NIR-F (NIR-FI group) and those who underwent elective laparoscopic ISR with lymphadenectomy for malignant rectal tumors without using NIR-FI (control group). Thirty were excluded from the analyses (13 died, 7 had pelvic recurrence, and 10 were lost to follow-up). The primary endpoint was the rate of SSAL within 2 years after the primary resection, whereas the secondary endpoint was the rate of natural defecation via the anus at 2 years after the primary resection. Using various statistical analyses, such as propensity score matching, the rate of SSAL was compared between groups. RESULTS: A total of 263 patients were analyzed [177 males and 86 females, median age 61 (27-84) years]. Prior to propensity score matching (n = 263), NIR-FI was performed in 70 patients (26.6%) The rates of SSAL were 1.4% (1/70) in the NIR-FI group and 10.4% (20/193) in the control group (p = 0.02). After propensity score matching (n = 163), the rates of SSAL were 1.5% (1/66) in the NIR-FI group and 11.7% (12/103) in the control group (p = 0.02). Propensity score analyses, as well as simple regression analyses, revealed that NIR-FI was associated with a significantly lower risk of SSAL (OR 0.10-0.13; p = 0.03-0.05). CONCLUSIONS: NIR-FI is useful in reducing the rate of SSAL after laparoscopic ISR.

Development of a performance rubric for transanal endoscopic rectal purse-string sutures.

BACKGROUND: Placing a transanal endoscopic rectal purse-string suture (taEPS) is the crucial first component of transanal total mesorectal excision (taTME). However, no structured training is available to improve the procedure-specific skills for taEPS. The aim of this study was to create a performance rubric to improve taEPS skills and provide preliminary evidence for its validity. METHODS: A performance rubric was created based on technical considerations for taEPS, identified by consulting with taTME surgical and performance assessment experts. Ten independent, blinded raters assessed 10 videotaped taEPS procedures of consecutive taTME cases, at National Cancer Center Hospital East (NCCHE), Chiba, Japan, in January 2018-March 2019 using the rubric and the Global Operative Assessment of Laparoscopic Skills (GOALS). Internal consistency and inter-rater reliabilities were calculated. Videotaped taEPS procedures were timed and assessed by the rubric. Correlation between rubric scores and suturing times were analyzed. RESULTS: The rubric consists of four items: loading the needle (LN), atraumatic needle passage (AP), planned suture path (PS), and overall performance (OA). Videotaped performances were graded on a 3-point Likert scale; scores were calculated as sums of the points. Cronbach's α for internal consistency was 0.713. Inter-rater reliabilities were LN: 0.73, AP: 0.76, PS: 0.71, and OA: 0.70. Rubric and GOALS scores were strongly correlated (r = 0.964, p < 0.001). In 112 consecutive taEPS performances, rubric scores were strongly correlated with suturing time (r = - 0.69, p < 0.001). Surgeons' experience with taTME was associated with rubric scores and suturing time. CONCLUSIONS: This study provides preliminary validation for the taEPS skill performance rubric. The rubric's structured training may facilitate skill acquisition by providing trainees with critical clinical considerations.

Outcomes of robot-assisted versus conventional laparoscopic low anterior resection in patients with rectal cancer: propensity-matched analysis of the National Clinical Database in Japan.

BACKGROUND: Robot-assisted laparoscopic surgery has several advantages over conventional laparoscopy. However, population-based comparative studies for low anterior resection are limited. This article aimed to compare peri-operative results of robot-assisted low anterior resection (RALAR) and laparoscopy. METHODS: This retrospective cohort study used data from patients treated with RALAR or conventional laparoscopic low anterior resection (CLLAR) between October 2018 and December 2019, as recorded in the Japanese National Clinical Database, a data set registering clinical information, perioperative outcomes, and mortality. Of note, the registry does not include information on the tumour location (centimetres from the anal verge) and diverting stoma creation. Perioperative outcomes, including rate of conversion to open surgery, were compared between RALAR and CLLAR groups. Confounding factors were adjusted for using propensity score matching. RESULTS: Of 21 415 patients treated during the study interval, 20 220 were reviewed. Two homogeneous groups of 2843 patients were created by propensity score matching. The conversion rate to open surgery was significantly lower in the RALAR group than in the CLLAR group (0.7 versus 2.0 per cent; P < 0.001). The RALAR group had a longer operating time (median: 352 versus 283 min; P < 0.001), less intraoperative blood loss (15 versus 20 ml; P < 0.001), a lower in-hospital mortality rate (0.1 versus 0.5 per cent; P = 0.007), and a shorter postoperative hospital stay (median: 13 versus 14 days; P < 0.001) compared with the CLLAR group. The CLLAR group had a lower rate of readmission within 30 days (2.4 versus 3.3 per cent; P = 0.045). CONCLUSION: These data highlight the reduced conversion rate, in-hospital mortality rate, intraoperative blood loss, and length of postoperative hospital stay for rectal cancer surgery in patients treated using robot-assisted laparoscopic surgery compared with laparoscopic low anterior resection.

Safety and feasibility of laparoscopic surgery for elderly rectal cancer patients in Japan: a nationwide study.

BACKGROUND: This study aimed to analyse the perioperative results from a national dataset of rectal cancer resections in elderly patients. METHODS: The clinical records of patients undergoing rectal cancer surgery between 2012 and 2014 were retrieved from the Japanese National Clinical Database and analysed retrospectively. Patients were categorized according to age and those 80 years or older were defined as elderly. Subgroups were also defined according to the surgical approach (laparoscopy versus open surgery). The short-term outcomes, including mortality, anastomotic leak, surgical site infections and medical complications were compared between subgroups. RESULTS: Of 56 175 patients undergoing rectal cancer surgery, some 6717 patients were elderly and laparoscopy was performed in 46.8 per cent of the sample. When comparing laparoscopy and open surgery in elderly patients, the operative mortality rate (1.5 versus 2.8 per cent; P < 0.001), the incidence of anastomotic leakage (5.2 versus 6.5 per cent; P = 0.026), surgical site infections (6.0 versus 8.0 per cent; P = 0.001), pneumonia (1.4 versus 2.5 per cent; P = 0.001), renal failure (0.7 versus 1.3 per cent; P = 0.016) and cardiac events (0.3 versus 0.8 per cent; P = 0.008) were lower for laparoscopy than for open surgery. The overall complication rate in elderly patients (19.5 per cent) was comparable to that in the younger group (P = 0.07). However, incidence of systemic complications was significantly higher in elderly than in younger patients (all P < 0.001). CONCLUSION: Laparoscopy was safe and feasible in elderly patients compared with open surgery. However, the rates of systemic complications were significantly higher than in younger patients.

Safety and feasibility of minimally invasive esophagectomy for elderly esophageal cancer patients.

The number of elderly patients with esophageal cancer has increased in recent years. The use of thoracoscopic esophagectomy has also increased, and its minimal invasiveness is believed to contribute to postoperative outcomes. However, the short- and long-term outcomes in elderly patients remain unclear. This study aimed to elucidate the safety and feasibility of minimally invasive esophagectomy in elderly patients. This retrospective study included 207 patients who underwent radical thoracoscopic esophagectomy for thoracic esophageal squamous cell carcinoma at Kobe University Hospital between 2005 and 2014. Patients were divided into non-elderly (<75 years) and elderly (≥75 years) groups. A propensity score matching analysis was performed for sex and clinical T and N stage, with a total of 29 matched pairs. General preoperative data, surgical procedures, intraoperative data, postoperative complications, in-hospital death, cancer-specific survival, and overall survival were compared between groups. The elderly group was characterized by lower preoperative serum albumin levels and higher American Society of Anesthesiologists grade. Intraoperative data and postoperative complications did not differ between the groups. The in-hospital death rate was 4% in the elderly group, which did not significantly differ from the non-elderly group. Cancer-specific survival was similar between the two groups. Although overall survival tended to be poor in the elderly group, it was not significantly worse than that of the non-elderly group. In conclusion, the short- and long-term outcomes of minimally invasive esophagectomy in elderly versus non-elderly patients were acceptable. Minimally invasive esophagectomy is a safe and feasible modality for elderly patients with appropriate indications.

Complement profile in microscopic polyangiitis and granulomatosis with polyangiitis: analysis using sera from a nationwide prospective cohort study.

OBJECTIVE: The complement cascade, especially the alternative pathway of complement, has been shown in basic research to be associated with anti-neutrophil cytoplasmic autoantibody (ANCA)-associated vasculitis (AAV). We aimed to elucidate relationships between serum complement components and clinical characteristics in AAV. METHOD: In a nationwide prospective cohort study (RemIT-JAV-RPGN), we measured the serum levels of C1q, C2, C3, C3b/iC3b, C4, C4b, C5, C5a, C9, factor B, factor D, factor H, factor I, mannose-binding lectin, and properdin in 52 patients with microscopic polyangiitis (MPA) and 39 patients with granulomatosis with polyangiitis (GPA). RESULTS: The properdin level of MPA and GPA was significantly lower than that of healthy donors. The properdin level was negatively correlated with the Birmingham Vasculitis Activity Score (BVAS) (ρ = -0.2148, p = 0.0409). The factor D level at 6 months was significantly positively correlated with the Vasculitis Damage Index (VDI) at 6, 12, and 24 months (ρ = 0.4207, 0.4132, and 0.3115, respectively). Patients with a higher ratio of C5a to C5 had higher neutrophil percentage and serum immunoglobulin G levels, and significantly lower creatinine levels. Cluster analysis divided the MPA and GPA patients into three subgroups. A principal component (PC) analysis aggregated 15 types of complements into alternative pathway-related PC 1 and complement classical pathway and common pathway-related PC 2. CONCLUSIONS: The serum levels of properdin and factor D were correlated with the BVAS and the VDI in MPA and GPA, respectively. Our analyses suggested the pathological heterogeneity of MPA and GPA from the aspect of complement components.

Effect of high ligation on survival of patients undergoing surgery for primary colorectal cancer and synchronous liver metastases.

BACKGROUND: Although R0 surgery is recommended for stage IV colorectal cancer, the degree of required lymphadenectomy has not been established. The aim of this study was to investigate the prognostic impact of high ligation (HL) of the feeding artery and the number of retrieved lymph nodes after R0 surgery for colorectal cancer and synchronous colorectal cancer liver metastasis (CRLM). METHODS: This was a multi-institutional retrospective analysis of patients with colorectal cancer and synchronous CRLM who had R0 surgery between January 1997 and December 2007. Clinical and pathological features were compared in patients who underwent HL and those who had a low ligation (LL). Kaplan-Meier analysis was performed to estimate the effect of HL on overall survival (OS). The impact of several risk factors on survival was analysed using the Cox proportional hazards model. RESULTS: Of 549 patients, 409 (74·5 per cent) had HL. Median follow-up was 51·4 months. HL significantly improved the 5-year OS rate (58·2 per cent versus 49·3 per cent for LL; P = 0·017). Multivariable analysis revealed HL to be a significant prognostic factor compared with LL (5-year mortality: hazard ratio (HR) 0·68, 95 per cent c.i. 0·51 to 0·90; P = 0·007). In subgroup analysis, the positive effect of HL on OS was greatest in patients with lymph node metastasis. CONCLUSION: HL of the feeding artery was associated with improved OS in patients with colorectal cancer and synchronous CRLM after R0 surgery.

ANTECEDENTES: Aunque se recomienda una cirugía R0 para el cáncer colorrectal (colorectal cancer, CRC) en estadio IV, no se ha establecido el grado de linfadenectomía requerida. El objetivo de este estudio fue investigar el impacto pronóstico de la ligadura alta (high ligation, HL) de la arteria que irriga el tumor y el número de ganglios linfáticos (lymph nodes, LN) identificados después de cirugía R0 en pacientes con cáncer colorrectal y metástasis hepáticas sincrónicas (colorectal cancer liver metastasis, CRLM). MÉTODOS: En este estudio se realizó un análisis retrospectivo multicéntrico de pacientes con CRC y CRLM sincrónicas en los que se realizó una cirugía R0 desde enero de 1997 hasta diciembre de 2007. Se compararon las características clínicas y patológicas entre los pacientes a los que, durante la cirugía R0, se practicó una HL frente a los que no se practicó esta técnica. El análisis de Kaplan-Meier se realizó para estimar el efecto de la HL en la supervivencia global (overall survival, OS). El impacto de varios factores de riesgo sobre la supervivencia se analizó utilizando el modelo de Cox de riesgo proporcional. RESULTADOS: Sobre un total de 549 pacientes, se realizó una HL en 409 (74,5%), y el período de seguimiento medio en esta cohorte fue de 51,4 meses. La HL mejoró significativamente la tasa de OS a los 5 años (HL 37,7% versus no HL 27,1%, P = 0,02). El análisis multivariable mostró que la HL era un factor pronóstico significativo en comparación con la no realización de una HL (cociente de riesgos instantáneos, hazard ratio, HR de muerte a 5 años = 0,68 (i.c. del 95% 0,51-0,90), P < 0,01)). En el análisis de subgrupos, el efecto positivo de la HL sobre la OS fue mayor en pacientes con metástasis ganglionares. CONCLUSIÓN: La ligadura alta de la arteria que irriga el tumor se asoció con una mejor OS en pacientes con CRC y CRLM sincrónicas después de una cirugía R0.

Preoperative intra-arterial chemotherapy with docetaxel, cisplatin, and peplomycin combined with intravenous chemotherapy using 5-fluorouracil for oral squamous cell carcinoma.

The objectives of this study were to evaluate survival in 141 patients with stage II-IV oral squamous cell carcinoma (OSCC) treated with preoperative intra-arterial chemotherapy with docetaxel, cisplatin, and peplomycin combined with intravenous chemotherapy using 5-fluorouracil (IADCPIVF) via the superficial temporal artery, and to clarify the prognostic factors. The study population included 59 patients with stage II OSCC, 34 with stage III, and 48 with stage IV. After IADCPIVF, 139 patients underwent surgery; minimally invasive surgeries (MIS) including excisional biopsy were performed on 96 patients with a remarkably good response to IADCPIVF. The primary tumour response rate was 99.3% (complete response rate 56.7%, good partial response rate 17.0%, fair partial response rate 25.5%). Additionally, there were no serious adverse events associated with IADCPIVF. The 5-year overall survival rate was 74.6% (stage II 83.6%, stage III 72.7%, stage IV 64.8%). In the multivariate analysis of survival, T classification and clinical tumour response were significant prognostic factors. Eight (8.3%) of the patients who received MIS had primary recurrence and six were salvaged. In conclusion, IADCPIVF is safe and efficacious for treating OSCC, and MIS could reduce the extent of primary tumour resection in the case of a remarkably good response.

Site-specific Chemotherapy Based on Predicted Primary Site by Pathological Profile for Carcinoma of Unknown Primary Site.

AIMS: Although platinum-based combination chemotherapies are commonly used for unfavourable subsets of cancer of unknown primary (CUP), the prognosis remains poor. Several studies have suggested that gene expression profiling or immunohistochemistry was useful for the prediction of primary sites in CUP, and site-specific therapy based on predicted primary sites might improve overall outcomes. In Japan, to identify primary sites, immunohistochemical tests were commonly used for CUP in clinical practice. However, it is unclear whether site-specific therapy based on predicted primary sites by pathological examination contributes survival benefit for unfavourable CUP subsets. PATIENTS AND METHODS: In this study, 122 patients with unfavourable subsets of CUP were retrospectively reviewed. Ninety patients assigned to cohort A after July 2012 had received chemotherapy according to predicted primary sites; 32 patients assigned to cohort B before June 2012 had received platinum-based empiric chemotherapy. RESULTS: In cohort A, 56 patients (62.2%) with predicted primary sites by pathological examination received site-specific therapy; 34 patients (37.8%) with unpredictable primary sites received platinum-based empiric chemotherapy, the same as cohort B. The median overall survival was 20.3 months in patients with predictable primary sites in cohort A and 10.7 months in those of cohort B, with a significant difference between these cohorts (P = 0.03, adjusted hazard ratio = 0.57, 95% confidence interval 0.34-0.94). CONCLUSION: Site-specific therapy based on predicted primary sites by pathological examination could improve prognosis in patients with an unfavourable subset of CUP.

Integrating 3D Rotational Angiography into Gamma Knife Planning.

3D rotational angiography provides remarkable spatial resolution for cerebrovascular disorders; however, it cannot be integrated directly into gamma knife planning due to the discrepancy of DICOM "tag" information, and most physicians still cannot benefit from 3D rotational angiography. Here, we describe a simple and easy technique to enable the integration of 3D rotational angiography.

Cytomegalic Inclusion Disease caused by Cytomegalovirus Infection in the Salivary Glands of an African Hedgehog (Atelerix arbiventris).

Cytomegalic inclusion disease (CID) in the salivary gland of African hedgehogs (Atelerix arbiventris) has been reported before, and is suspected to reflect a cytomegalovirus infection. However, a recent ultrastructural study reported that African hedgehog CID reflected oncocytic metaplasia, mimicking a cytomegalovirus infection. We examined the submandibular and sublingual salivary glands of a 1-year-old male African hedgehog. Histologically, there were multiple foci composed of cytomegalic cells with intranuclear inclusion bodies. Ultrastructurally, viral particles (109-118 nm in diameter) were observed in the nuclei of the cytomegalic cells. There were numerous vesicles containing various numbers of enveloped viruses in the cytoplasm. We also attempted to detect viral DNA fragments by degenerate polymerase chain reaction and obtained amplicons of a predicted size. Phylogenetic analysis indicated that the virus is a betaherpesvirus, comparatively related to human and rodent cytomegaloviruses. The present study suggested that African hedgehog CIDs also include those caused by the cytomegalovirus.

Smoking is a risk factor for pulmonary metastasis in colorectal cancer.

AIM: The hepatic microenvironment, which may include chronic inflammation and fibrosis, is considered to contribute to the pathogenesis of liver metastases of colorectal cancer. A similar mechanism is anticipated for pulmonary metastases, although no reports are available. Smoking causes pulmonary inflammation and fibrosis. Thus, we hypothesized that smokers would be especially affected by pulmonary metastases of colorectal cancer. In this study, we attempted to clarify the impact of smoking on pulmonary metastasis of colorectal cancer. METHOD: Between September 2005 and December 2010 we reviewed 567 patients with pathological Stage I, II or III colorectal cancer, whose clinicopathological background included a preoperative smoking history, pack-year history from medical records. Univariate and multivariate analyses using the Cox proportional hazard model were performed to determine the independent prognostic factors for pulmonary metastasis-free survival. RESULTS: Pulmonary metastases occurred in 39 (6.9%) patients. The smoking histories revealed 355 never smokers, 119 former smokers and 93 current smokers among the subjects. Multivariate analysis revealed that being a current smoker (hazard ratio = 2.72, 95% CI 1.18-6.25; P = 0.02) was an independent risk factor for pulmonary metastases. CONCLUSION: Smoking may be a risk factor for pulmonary metastasis of colorectal cancer. Cessation of smoking should be recommended to prevent pulmonary metastasis, although further basic and clinical studies are required.

Meta-analysis of the risk of small bowel obstruction following open or laparoscopic colorectal surgery.

BACKGROUND: One of the potential advantages of laparoscopic compared with open colorectal surgery is a reduction in postoperative bowel obstruction events. Early reports support this proposal, but accumulated evidence is lacking. METHODS: A systematic review and meta-analysis was performed of randomized clinical trials and observational studies by searching the PubMed and Cochrane Library databases from 1990 to August 2015. The primary outcomes were early and late postoperative bowel obstruction following laparoscopic and open colorectal surgery. Both ileus and bowel obstruction were defined as a postoperative bowel obstruction. Subgroup and sensitivity analyses were performed, and a random-effects model was used to account for the heterogeneity among the studies. RESULTS: Twenty-four randomized clinical trials and 88 observational studies were included in the meta-analysis; 106 studies reported early outcome and 12 late outcome. Collectively, these studies reported on the outcomes of 148 392 patients, of whom 58 133 had laparoscopic surgery and 90 259 open surgery. Compared with open surgery, laparoscopic surgery was associated with reduced rates of early (odds ratio 0·62, 95 per cent c.i. 0·54 to 0·72; P < 0·001) and late (odds ratio 0·61, 0·41 to 0·92; P = 0·019) postoperative bowel obstruction. Weighted mean values for early postoperative bowel obstruction were 8 (95 per cent c.i. 6 to 10) and 5 (3 to 7) per cent for open and laparoscopic surgery respectively, and for late bowel obstruction were 4 (2 to 6) and 3 (1 to 5) per cent respectively. CONCLUSION: The reduction in postoperative bowel obstruction demonstrates an advantage of laparoscopic surgery in patients with colorectal disease.

Intra-arterial chemoradiation therapy with weekly low-dose cisplatin for squamous cell carcinoma of the maxillary sinus.

A new intra-arterial chemoradiation regimen that involves infusing low-dose cisplatin in combination with definitive irradiation was used in 36 patients diagnosed with squamous cell carcinoma of the maxillary sinus. The safety and therapeutic efficacy of this regimen were reviewed retrospectively. An intra-arterial catheter was inserted in a retrograde manner into the target artery via the superficial temporal artery or occipital artery. Intra-arterial infusion was performed using cisplatin at a dose of 20-50mg/m(2) per week for 6-8 weeks. At the same time, sodium thiosulphate was infused as a neutralizing agent. Irradiation was performed at 60Gy in 30 fractions. All 36 patients completed treatment. Grade 3 adverse events occurred in only seven patients (19.4%) and no grade 4 events were noted. As a primary therapy, the complete response rate was 83.3%, the partial response rate was 16.7%, and the overall response rate was 100%. The 2-year local control rate was 63.0%, and the 2-year overall survival rate was 75.5%. The 2-year preservation rate of the hard palate was 97.1%, that of the eyeball was 97.2%, and that of visual function was 94.4%. This treatment regimen can contribute to improving the quality of life of patients without reducing the curability of the therapy.

Comparing immunocompetent and immunodeficient mice as animal models for bone tissue engineering.

OBJECTIVES: To understand the differences and similarities between immunocompetent and immunodeficient mice as ectopic transplantation animal models for bone tissue engineering. MATERIALS AND METHODS: Osteogenic cells from mouse leg bones were cultured, seeded on ß-TCP granules, and transplanted onto the backs of either immunocompetent or immunodeficient nude mice. At 1, 2, 4, and 8 weeks postoperatively, samples were harvested and evaluated by hematoxylin-eosin staining, tartrate-resistant acid phosphatase (TRAP) staining, and immunohistochemical staining and quantitative PCR. RESULTS: In immunocompetent mice, inflammatory cell infiltration was evident at 1 week postoperatively and relatively higher expression of TNF-α and IL-4 was observed. In immunodeficient mice, new bone area and the number of TRAP-positive cells were larger at 4 weeks than in immunocompetent mice. The volume of new bone area in immunodeficient mice was reduced by 8 weeks. CONCLUSIONS: Bone regeneration was feasible in immunocompetent mice. However, some differences were observed between immunocompetent and immunodeficient mice in the bone regeneration process possibly due to different cytokine expression, which should be considered when utilizing in vivo animal models.

Expression of myeloperoxidase in acute myeloid leukemia blasts mirrors the distinct DNA methylation pattern involving the downregulation of DNA methyltransferase DNMT3B.

Myeloperoxidase (MPO) has been associated with both a myeloid lineage commitment and favorable prognosis in patients with acute myeloid leukemia (AML). DNA methyltransferase inhibitors (decitabine and zeburaline) induced MPO gene promoter demethylation and MPO gene transcription in AML cells with low MPO activity. Therefore, MPO gene transcription was directly and indirectly regulated by DNA methylation. A DNA methylation microarray subsequently revealed a distinct methylation pattern in 33 genes, including DNA methyltransferase 3 beta (DNMT3B), in CD34-positive cells obtained from AML patients with a high percentage of MPO-positive blasts. Based on the inverse relationship between the methylation status of DNMT3B and MPO, we found an inverse relationship between DNMT3B and MPO transcription levels in CD34-positive AML cells (P=0.0283). In addition, a distinct methylation pattern was observed in five genes related to myeloid differentiation or therapeutic sensitivity in CD34-positive cells from AML patients with a high percentage of MPO-positive blasts. Taken together, the results of the present study indicate that MPO may serve as an informative marker for identifying a distinct and crucial DNA methylation profile in CD34-positive AML cells.