Coevolutionary genetic algorithm for constraint satisfaction with a genetic repair operator for effective schemata formation

We discuss a coevolutionary genetic algorithm for constraint satisfaction. Our basic idea is to explore effective genetic information in the population, i.e., schemata, and to exploit the genetic information in order to guide the population to better solutions. Our coevolutionary genetic algorithm (CGA) consists of two GA populations; the first GA, called “H-GA”, searches for the solutions in a given environment (problem), and the second GA, called “P-GA”, searches for effective genetic information involved in the H-GA, namely, good schemata. Thus, each individual in P-GA consists of alleles in H-GA or “don't care” symbol representing a schema in the H-GA. These GA populations separately evolve in each genetic space at different abstraction levels and affect with each other by two genetic operators: “superposition” and “transcription”. We then applied our CGA to constraint satisfaction problems (CSPs) incorporating a new stochastic “repair” operator for P-GA to raise the consistency of schemata with the (local) constraint conditions in CSPs. We carried out two experiments: First, we examined the performance of CGA on various “general” CSPs that are generated randomly for a wide variety of “density” and “tightness” of constraint conditions in the CSPs that are the basic measures of characterizing CSPs. Next, we examined “structured” CSPs involving latent “cluster” structures among the variables in the CSPs. For these experiments, computer simulations confirmed us the effectiveness of our CGA</p

Semen quality of 1559 young men from four cities in Japan: a cross-sectional population-based study

Objectives: To provide information of semen quality among normal young Japanese men and indicate the frequency of reduced semen quality. Design: Cross-sectional, coordinated studies of Japanese young men included from university areas. The men had to be 18-24 years, and both the man and his mother had to be born in Japan. Background information was obtained from questionnaires. Standardised and quality-controlled semen analyses were performed, reproductive hormones analysed centrally and results adjusted for confounding factors. Setting: Four study centres in Japan (Kawasaki, Osaka, Kanazawa and Nagasaki). Participants: 1559 men, median age 21.1 years, included during 1999-2003. Outcome measures: Semen volume, sperm concentration, total sperm count, sperm motility, sperm morphology and reproductive hormone levels. Results: Median sperm concentration was 59 (95% CI 52 to 68) million/ml, and 9% and 31.9% had less than 15 and 40 million/ml, respectively. Median percentage of morphologically normal spermatozoa was 9.6 (8.8 to 10.3)%. Small, but statistically significant, differences were detected for both semen and reproductive hormone variables between men from the four cities. Overall, the semen values were lower than those of a reference population of 792 fertile Japanese men. Conclusions: Assuming that the investigated men were representative for young Japanese men, a significant proportion of the population had suboptimal semen quality with reduced fertility potential, and as a group they had lower semen quality than fertile men. However, the definitive role-if any-of low semen quality for subfertility and low fertility rates remain to be investigated

Demographic, behavioral, dietary, and socioeconomic characteristics related to persistent organic pollutants and mercury levels in pregnant women in Japan

Persistent organic pollutants and mercury are known environmental chemicals that have been found to be ubiquitous in not only the environment but also in humans, including women of reproductive age. The purpose of this study was to evaluate the association between personal lifestyle characteristics and environmental chemical levels during the perinatal period in the general Japanese population. This study targeted 322 pregnant women enrolled in the Hokkaido Study on Environment and Children’s Health. Each participant completed a self-administered questionnaire and a food-frequency questionnaire to obtain relevant information on parental demographic, behavioral, dietary, and socioeconomic characteristics. In total, 58 non-dioxin-like polychlorinated biphenyls, 17 dibenzo-p-dioxins and -dibenzofuran, and 12 dioxin-like polychlorinated biphenyls congeners, perfluorooctane sulfonate, perfluorooctanoic acid, and mercury were measured in maternal samples taken during the perinatal period. Linear regression models were constructed against potential related factors for each chemical concentration. Most concentrations of environmental chemicals were correlated with the presence of other environmental chemicals, especially in the case of non-dioxin-like polychlorinated biphenyls and, polychlorinated dibenzo-p-dioxins and -dibezofurans and dioxin-like polychlorinated biphenyls which had similar exposure sources and persistence in the body. Maternal smoking and alcohol habits, fish and beef intake and household income were significantly associated with concentrations of environmental chemicals. These results suggest that different lifestyle patterns relate to varying exposure to environmental chemicals

FLT-PET for the Evaluation of Lung Cancer Patients Treated with Carbon-Ion Radiation Therapy: Initial Results

Aim: To investigate the clinical value of FLT-PET in the evaluation of lung cancer patients treated with carbon-ion radiation therapy (CIRT). Materials & Methods: Eighteen consecutive patients (pts) with lung cancer who are going to be treated with CIRT received FLT-PET/CT before (18 pts) and 3 months after CIRT (13 pts). Fifty minutes after intravenous injection of approximately 296 MBq of FLT, PET/CT data were acquired. Maximal standardized uptake values (SUV) were measured and compared with short-term effect evaluated by the reduction of maximal tumor diameter measured by CT at 3 months post CIRT. Initial FLT uptake in the tumor was compared with the occurrence of local recurrence and/or metastasis. The study plan was approved by the Institutional Ethical Committee and informed consent was obtained from all patients before each FLT-PET examination. Results: Before CIRT, squamous cell carcinomas tended to show higher FLT uptake than adenocarcinomas did, although the difference was not statistically significant (3.70 +/- 1.88 versus 2.31 +/- 1.17, p=0.058). Three months after CIRT, both maximal diameter and maximal FLT-uptake showed significant reduction compared to those before CIRT (p=0.004 for maximal diameter and p=0.002 for SUV). There was a significant correlation between the reduction rate (RR) of FLT-uptake [(SUVpre - SUVpost)/SUVpre] and the reduction rate of maximum diameter [(Diameter-pre - Diameter-post)/Diameter-pre] (p=0.003). In 7 of 13 pts, CT showed the development of radiation pneumonitis (RP) 3 months after CIRT, and mild to weak FLT uptake was observed in the area of RP. Pts developing RP tended to show lower reduction rate of FLT-uptake than pts not developing RP (0.25 +/- 0.41 with RP versus 0.53 +/- 0.09 without RP, p=0.063). In 14 pts having more than 6-months follow-up period, 7 pts developed local recurrence and/or metastases, and pts having recurrence/metastases tended to show higher SUVpre, although not statistically significant (3.74 +/- 1.39 versus 2.81 +/- 0.82, p=0.116). Conclusion: Although the number of pts is limited and the follow up period is not long enough, the present preliminary data suggests the feasibility of FLT-PET in lung cancer patients being treated with CIRT. The presence of RP can modify the FLT uptake in the treated tumor and may cause underestimation of the CIRT effect. Although there is a possibility that higher tumor uptake of FLT before CIRT can be a predictor of recurrence/metastases, more cases are necessary to prove this.Annual Congress of the European Association of Nuclear Medicine 200

PET/CT with 3\u27-deoxy-3\u27-[18F]fluorothymidine for lung cancer patients receiving carbon-ion radiotherapy

OBJECTIVE: The aim of this study was to investigate the clinical value of 3\u27-deoxy-3\u27-[F]fluorothymidine-positron emission tomography/computed tomography (FLT-PET/CT) for lung cancer patients receiving carbon-ion radiotherapy. METHODS: Twenty consecutive patients with lung cancer underwent FLT-PET/CT before and after carbon-ion radiotherapy. Fifty minutes after intravenous injection of approximately 300 MBq of FLT, PET/CT data were acquired. Maximal standardized uptake value of the tumor was measured, from which the reduction rate of tumor FLT uptake was calculated. After treatment, the patients were followed (17-42 months for survivors) for the development of recurrence and survival. RESULTS: Primary responses to carbon-ion radiotherapy were partial in 13 patients, stable disease in six patients, and nonevaluable in one patient. Although tumor FLT uptake significantly decreased after treatment (P<0.001), the presence of radiation pneumonitis hampered its precise evaluation. During the follow-up period, nine patients developed recurrence, and seven patients died including two deaths from other causes. Pretreatment FLT uptake of patients who developed recurrence and who died of lung cancer were significantly higher than that of patients who did not (P=0.008 and 0.007, respectively). Kaplan-Meier analysis using a cut-off value also supported the prognostic value of pre-carbon-ion radiotherapy FLT-PET/CT. CONCLUSION: This investigation suggests that FLT-PET/CT is feasible in evaluating lung cancer patients undergoing carbon-ion radiotherapy. The presence of radiation pneumonitis can influence tumor FLT uptake and needs special attention. Pre-carbon-ion radiotherapy FLT-PET/CT seems to have a prognostic value and may contribute to decision-making on the treatment strategy

Refractory peritonitis by spontaneous perforation of the common bile duct in a patient receiving peritoneal dialysis

Abstract Background Patients with end-stage renal disease are in an immune-compromised state, with infection being the most common cause of mortality among those undergoing dialysis. Case presentation A 73-year-old woman who had received 6 months of peritoneal dialysis (PD) presented with peritoneal irritation symptoms during hospitalization for examination of PD effluent turbidity. Emergent laparotomy was performed for acute biliary peritonitis, but the cause was undetermined because of severe adhesion, and surgery ended with washing and palliative drainage. Postoperative endoscopic retrograde cholangiopancreatography revealed spontaneous perforation of the common bile duct (CBD), and she was transferred to the intensive care unit (ICU) for treatment of septic shock. Treatment included antibiotics, drainage, mechanical ventilation, and continuous hemodiafiltration, but infection spread into the retroperitoneal tissue and right thigh gradually. On ICU day 53, she died due to multiple organ failure. Conclusions Acute peritonitis due to spontaneous perforation of the CBD is very rare, and to our knowledge, this is the first report of biliary peritonitis in a patient receiving PD. Physicians should pay special attention to refractory peritonitis, including biliary peritonitis, occurring in patients receiving PD because some cases can be fatal