Manabu Akahane

The Effects of Sex on Out-of-Hospital Cardiac Arrest Outcomes

OBJECTIVEnWe examined the effects of sex on out-of-hospital cardiac arrest outcomes. There is evidence that women are more likely to survive cardiac arrest than men. However, few large studies have examined these sex differences in detail. It is unknown whether the female survival advantage is age-specific or whether sex affects neurologic outcomes after cardiac arrest events.nnnMETHODSnData were analyzed from a nationwide population-based out-of-hospital cardiac arrest database (between January 2005 and December 2007) involving 318,123 patients (male: 188,357, female: 129,766) to assess the effects of sex on out-of-hospital cardiac arrest outcomes in Japan. We selected 276,590 patients aged 20 to 89 years with out-of-hospital cardiac arrest and compared the frequencies of initial cardiac rhythms, 1-month survival rates, and favorable neurologic outcome rates between sexes.nnnRESULTSnThe incidence of out-of-hospital cardiac arrest was higher in men than in women (men: 0.12%; women: 0.07%). Men were witnessed more often while out-of-hospital cardiac arrest was occurring (men: 42.1% and women: 36.9%), typically presented with initial ventricular fibrillation/ventricular tachycardia rhythms, and had a higher 1-month survival rate overall after out-of-hospital cardiac arrest events (men: 5.2% and women: 4.3%). However, the rate of survival with a favorable neurologic outcome for women aged 30 to 49 years was significantly higher than that for men within the same age range. Among patients initially presenting with ventricular fibrillation/ventricular tachycardia, the rate of survival with favorable neurologic outcome was higher for women than men in the group aged 40 to 59 years.nnnCONCLUSIONnOur results suggest that men have a higher 1-month survival rate after out-of-hospital cardiac arrest because of a higher frequency of ventricular fibrillation/ventricular tachycardia presentation compared with women. Although patients of both sexes with out-of-hospital cardiac arrest initially presenting with ventricular fibrillation/ventricular tachycardia exhibited similar overall survival rates, the rate of survival with favorable neurologic outcome was significantly higher for women than men in the group aged 40 to 59 years.

Predictors of distal radioulnar joint instability in distal radius fractures.

PURPOSEnA tear of the triangular fibrocartilage complex (TFCC) is the most frequent soft tissue injury associated with fractures of the distal radius, and repair of the deep ligamentous portion of the TFCC is considered when the tear contributes to instability of the distal radioulnar joint (DRUJ). The purpose of this prospective cohort study was to identify predictors of DRUJ instability accompanying unstable distal radius fractures.nnnMETHODSnBetween 2002 and 2007, we prospectively treated 163 consecutive patients with unstable distal radius fractures with the volar locking plating system. Complete radioulnar ligament tears representing DRUJ instability were present in 11 of 163 distal radius fractures. We tested univariate associations between DRUJ instability and potential predictors and conducted multivariate analysis to establish independent predictors of instability. We applied receiver operating characteristics curves within the significant risk factors to determine threshold values.nnnRESULTSnIn univariate analyses, only the radial and sagittal translation ratios of the fracture site were significant predictors of DRUJ instability. Multivariate logistic regression analysis confirmed that the radial translation ratio, which corresponds to a normalized DRUJ gap, was a significant risk factor. According to the receiver operating characteristics curve for the radial translation ratio, the area under the curve was 0.89. A cutoff value of 15% for the radial translation ratio showed the highest diagnostic accuracy rate.nnnCONCLUSIONSnA radiographic finding of a normalized DRUJ gap on posteroanterior views was the most important predictor to identify DRUJ instability accompanying unstable distal radius fractures. The relative risk of instability increases by 50% when the ratio of DRUJ widening increases by 1%.

Development of a Web-Based Survey for Monitoring Daily Health and its Application in an Epidemiological Survey

Background Early detection of symptoms arising from exposure to pathogens, harmful substances, or environmental changes is required for timely intervention. The administration of Web-based questionnaires is a potential method for collecting information from a sample population. Objective The objective of our study was to develop a Web-based daily questionnaire for health (WDQH) for symptomatic surveillance. Methods We adopted two different survey methods to develop the WDQH: an Internet panel survey, which included participants already registered with an Internet survey company, and the Tokyo Consumers’ Co-operative Union (TCCU) Internet survey, in cooperation with the Japanese Consumers’ Co-operative Union, which recruited participants by website advertising. The Internet panel survey participants were given a fee every day for providing answers, and the survey was repeated twice with modified surveys and collection methods: Internet Panel Survey I was conducted every day, and Internet Panel Survey II was conducted every 3 days to reduce costs. We examined whether the survey remained valid by reporting health conditions on day 1 over a 3-day period, and whether the response rate would vary among groups with different incentives. In the TCCU survey, participants were given a fee only for initially registering, and health information was provided in return for survey completion. The WDQH included the demographic details of participants and prompted them to answer questions about the presence of various symptoms by email. Health information collected by the WDQH was then used for the syndromic surveillance of infection. Results Response rates averaged 47.3% for Internet Panel Survey I, 42.7% for Internet Panel Survey II, and 40.1% for the TCCU survey. During a seasonal influenza epidemic, the WDQH detected a rapid increase in the number of participants with fever through the early aberration reporting system. Conclusions We developed a health observation method based on self-reporting by participants via the Internet. We validated the usefulness of the WDQH by its practical use in syndromic surveillance.

Yusho and its latest findings—A review in studies conducted by the Yusho Group

The Yusho incident is an unprecedented mass food poisoning that occurred in Japan in 1968. It was caused by the ingestion of rice bran oil contaminated with polychlorinated biphenyls (PCBs) and various dioxins and dioxin-like compounds, such as polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs). The victims of Yusho have suffered from characteristic skin manifestations associated with systemic, ophthalmological, and mucosal symptoms for a long period of time. The Study Group of Yusho (the Yusho Group) has been conducting annual medical check-ups on Yusho victims for more than 45years. Since 2002, when concentrations of dioxins in the blood of Yusho patients started to be measured, the pharmacokinetics of dioxins, relationship between blood levels of dioxins and symptoms/signs in patients directly exposed to dioxins, and the adverse effects on the next generation have become dramatically clear. Herein we review recent findings of studies conducted by the Yusho Group to evaluate chronic dioxin-induced toxicity to the next generation as well as Yusho patients in comparison with a similar food mass poisoning, the Yucheng incident. Additionally, we summarized basic studies carried out by the Yusho Group to re-evaluate the mechanisms of dioxin toxicities in experimental models and various functions of the aryl hydrocarbon receptor (AhR), known as the dioxin receptor, pathway.

Prevalence of insomnia among residents of Tokyo and osaka after the great East Japan earthquake: a prospective study.

Background The Great East Japan Earthquake occurred on March 11, 2011. Tokyo and Osaka, which are located 375 km and 750 km, respectively, from the epicenter, experienced tremors of 5.0 lower and 3.0 seismic intensity on the Japan Meteorological Agency scale. The Great East Japan Earthquake was the fourth largest earthquake in the world and was accompanied by a radioactive leak at a nuclear power plant and a tsunami. In the aftermath of a disaster, some affected individuals presented to mental health facilities with acute stress disorder (ASD) and/or post-traumatic stress disorder (PTSD). However, few studies have addressed mental stress problems other than ASD or PTSD among the general public immediately after a disaster. Further, the effects of such a disaster on residents living at considerable distances from the most severely affected area have not been examined. Objective This study aimed to prospectively analyze the effect of a major earthquake on the prevalence of insomnia among residents of Tokyo and Osaka. Methods A prospective online questionnaire study was conducted in Tokyo and Osaka from January 20 to April 30, 2011. An Internet-based questionnaire, intended to be completed daily for a period of 101 days, was used to collect the data. All of the study participants lived in Tokyo or Osaka and were Consumers’ Co-operative Union (CO-OP) members who used an Internet-based food-ordering system. The presence or absence of insomnia was determined before and after the earthquake. These data were compared after stratification for the region and participants’ age. Multivariate analyses were conducted using logistic regression and a generalized estimating equation. This study was conducted with the assistance of the Japanese CO-OP. Results The prevalence of insomnia among adults and minors in Tokyo and adults in Osaka increased significantly after the earthquake. No such increase was observed among minors in Osaka. The overall adjusted odds ratios for the risk of insomnia post-earthquake versus pre-earthquake were 1.998 (95% CI 1.571–2.542) for Tokyo, 1.558 (95% CI 1.106–2.196) for Osaka, and 1.842 (95% CI,1.514–2.242) for both areas combined. Conclusions The prevalence of insomnia increased even in regions that were at a considerable distance from the epicenter. Both adults and minors in Tokyo, where the seismic intensity was greater, experienced stress after the earthquake. In Osaka, where the earthquake impact was milder, disturbing video images may have exacerbated insomnia among adults.

Immediate Defibrillation or Defibrillation After Cardiopulmonary Resuscitation

Abstract Objectives. This study aimed to determine whether short cardiopulmonary resuscitation (CPR) by emergency medical services before defibrillation (CPR first) has a better outcome than immediate defibrillation followed by CPR (shock first) in patients with ventricular fibrillation/pulseless ventricular tachycardia (VF/pulseless VT) out-of-hospital cardiac arrest. Methods. We analyzed a national database between 2006 and 2008, and included patients aged 18 years or more who had witnessed cardiac arrests and whose first recorded rhythm was VF/pulseless VT. Those study subjects were divided into five groups in accordance with the CPR/defibrillation intervention sequence. Each group was subdivided into call-to-response intervals of <5 minutes and ≥5 minutes. We identified 267 patients in the shock-first group and 6,407 patients in the CPR-first group. One-month survival and neurologically favorable one-month survival rates were used for outcome measures. The association of intervention type on outcomes (one-month survival or neurologically favorable one-month survival) was analyzed using multivariate logistic regression analyses by adjusting potential confounding factors such as survey year, gender, age (years), bystander CPR, intubation, and call-to-response interval (min). Results. The overall one-month survival rate was 26.2% (3,125/11,941) and the neurologically favorable one-month survival rate was 16.6% (1,983/11,934). The CPR-first group had a one-month survival rate of 27.8% (1,780/6,407) and a neurologically favorable one-month survival rate of 17.8% (1,140/6,404), and the shock-first group had survival rates of 24.7% (66/267) and 18.4% (49/267), respectively. There were no significant differences in one-month survival and neurologically favorable one-month survival in these two primary comparison groups (odds ratio [95% confidence interval], 0.85 [0.64–1.13] and 1.04 [0.76–1.42], respectively). Logistic regression analysis showed that neither CPR first nor shock first was associated with the rate of one-month survival or neurologically favorable one-month survival, after adjusting for potential confounders. Conclusions. In our study, CPR prior to attempted defibrillation did not present a better outcome compared with shock first as measured by either one-month survival or neurologically favorable one-month survival, after adjusting for potential confounders. Further studies are required to determine whether CPR first has an advantage over shock first.

Osteogenesis of cryopreserved osteogenic matrix cell sheets

Cryopreservation of tissue engineered bone (TEB), whilst maintaining its osteogenic ability, is imperative for large-scale clinical application. We previously reported a novel cell transplantation method, in which bone-marrow-derived mesenchymal stem cells (BMSCs) were cultured to confluence and differentiated down the osteogenic lineage to form osteogenic matrix cell sheets (OMCS). OMCS have high alkaline phosphatase (ALP) activity and osteocalcin (OC) contents and can be easily used for producing TEB. The aim of the present study was to investigate whether TEB produced by cryopreserved OMCS maintains sufficient osteogenic potential in vivo. OMCS were prepared and divided into three groups according to storage period of cryopreservation (fresh (no cryopreservation), 4 week and 12 week cryopreservation groups). OMCS were cryopreserved by storage in freezing medium (Cell Banker 1®) at -80 °C. Cryopreserved OMCSs were rapidly thawed at room temperature and wrapped around Hydroxyapatite (HA) scaffolds prior to implantation into subcutaneous sites in rats, to determine their in vivo bone-forming capability. The constructs were harvested 4 weeks after transplantation and examined histologically and biochemically. Histological analysis of the constructs showed extensive bone formation in the HA pores with high ALP activity and OC content detected in the cryopreservation groups. The present study clearly indicates that cryopreserved/thawed OMCS are still capable of producing mineralized matrix on scaffolds, resulting in bone formation. This cryopreservation technique could be applied for hard tissue reconstruction to ease the cell preparation method prior to time of use.

Distal Radioulnar Joint Stress Radiography for Detecting Radioulnar Ligament Injury

PURPOSEnTo determine the reliability and efficacy of clenched-fist stress radiographs in patients with radioulnar ligament injury.nnnMETHODSnWe examined 30 patients with chronic radioulnar ligament injury. These patients underwent stress radiography, which included clenched-fist posteroanterior (PA) views in forearm pronation and computed tomography in pronation. We measured distal radioulnar joint (DRUJ) gap distance and ulnar variance using clenched-fist PA views. We measured the radioulnar ratio with pronated computed tomography to quantify dorsal translation of the ulnar head. We analyzed these radiographic data and compared them between the injured and contralateral sides. We examined test-retest reliability and interobserver and intraobserver reliability using intraclass correlation coefficients as a measurement of the DRUJ gap distance in clenched-fist PA views.nnnRESULTSnThe DRUJ gap distance observed with clenched-fist PA views in injured wrists was significantly greater than in the contralateral side. The DRUJ gap distance observed with stress radiography significantly correlated with the magnitude of the radioulnar ratio in forearm pronation. We found a significant test-retest reliability for measuring DRUJ gap distance using clenched-fist PA views, as well as a significant level of intraobserver and interobserver reliability.nnnCONCLUSIONSnThe DRUJ gap distance observed with clenched-fist PA radiography in forearm pronation was a reliable parameter and may be useful for evaluating DRUJ instability.nnnTYPE OF STUDY/LEVEL OF EVIDENCEnDiagnostic II.

Utility of tricalcium phosphate and osteogenic matrix cell sheet constructs for bone defect reconstruction

AIMnTo determine the effects of transplanting osteogenic matrix cell sheets and beta-tricalcium phosphate (TCP) constructs on bone formation in bone defects.nnnMETHODSnOsteogenic matrix cell sheets were prepared from bone marrow stromal cells (BMSCs), and a porous TCP ceramic was used as a scaffold. Three experimental groups were prepared, comprised of TCP scaffolds (1) seeded with BMSCs; (2) wrapped with osteogenic matrix cell sheets; or (3) both. Constructs were implanted into a femoral defect model in rats and bone growth was evaluated by radiography, histology, biochemistry, and mechanical testing after 8 wk.nnnRESULTSnIn bone defects, constructs implanted with cell sheets showed callus formation with segmental or continuous bone formation at 8 wk, in contrast to TCP seeded with BMSCs, which resulted in bone non-union. Wrapping TCP constructs with osteogenic matrix cell sheets increased their osteogenic potential and resulting bone formation, compared with conventional bone tissue engineering TCP scaffolds seeded with BMSCs. The compressive stiffness (mean ± SD) values were 225.0 ± 95.7, 30.0 ± 11.5, and 26.3 ± 10.6 MPa for BMSC/TCP/Sheet constructs with continuous bone formation, BMSC/TCP/Sheet constructs with segmental bone formation, and BMSC/TCP constructs, respectively. The compressive stiffness of BMSC/TCP/Sheet constructs with continuous bone formation was significantly higher than those with segmental bone formation and BMSC/TCP constructs.nnnCONCLUSIONnThis technique is an improvement over current methods, such as TCP substitution, and is useful for hard tissue reconstruction and inducing earlier bone union in defects.

Osteogenic Matrix Cell Sheets Facilitate Osteogenesis in Irradiated Rat Bone

Reconstruction of large bone defects after resection of malignant musculoskeletal tumors is a significant challenge in orthopedic surgery. Extracorporeal autogenous irradiated bone grafting is a treatment option for bone reconstruction. However, nonunion often occurs because the osteogenic capacity is lost by irradiation. In the present study, we established an autogenous irradiated bone graft model in the rat femur to assess whether osteogenic matrix cell sheets improve osteogenesis of the irradiated bone. Osteogenic matrix cell sheets were prepared from bone marrow-derived stromal cells and co-transplanted with irradiated bone. X-ray images at 4 weeks after transplantation showed bridging callus formation around the irradiated bone. Micro-computed tomography images at 12 weeks postoperatively showed abundant callus formation in the whole circumference of the irradiated bone. Histology showed bone union between the irradiated bone and host femur. Mechanical testing showed that the failure force at the irradiated bone site was significantly higher than in the control group. Our study indicates that osteogenic matrix cell sheet transplantation might be a powerful method to facilitate osteogenesis in irradiated bones, which may become a treatment option for reconstruction of bone defects after resection of malignant musculoskeletal tumors.