Detection of current-sheet and bipolar ion flows in a self-generated antiparallel magnetic field of laser-produced plasmas for magnetic reconnection research.

Magnetic reconnection in laser-produced magnetized plasma is investigated by using optical diagnostics. The magnetic field is generated via the Biermann battery effect, and the inversely directed magnetic field lines interact with each other. It is shown by self-emission measurement that two colliding plasmas stagnate on a midplane, forming two planar dense regions, and that they interact later in time. Laser Thomson scattering spectra are distorted in the direction of the self-generated magnetic field, indicating asymmetric ion velocity distribution and plasma acceleration. In addition, the spectra perpendicular to the magnetic field show different peak intensity, suggesting an electron current formation. These results are interpreted as magnetic field dissipation, reconnection, and outflow acceleration. Two-directional laser Thomson scattering is, as discussed here, a powerful tool for the investigation of microphysics in the reconnection region.

Direct observations of pure electron outflow in magnetic reconnection.

Magnetic reconnection is a universal process in space, astrophysical, and laboratory plasmas. It alters magnetic field topology and results in energy release to the plasma. Here we report the experimental results of a pure electron outflow in magnetic reconnection, which is not accompanied with ion flows. By controlling an applied magnetic field in a laser produced plasma, we have constructed an experiment that magnetizes the electrons but not the ions. This allows us to isolate the electron dynamics from the ions. Collective Thomson scattering measurements reveal the electron Alfvénic outflow without ion outflow. The resultant plasmoid and whistler waves are observed with the magnetic induction probe measurements. We observe the unique features of electron-scale magnetic reconnection simultaneously in laser produced plasmas, including global structures, local plasma parameters, magnetic field, and waves.

High-power laser experiment on developing supercritical shock propagating in homogeneously magnetized plasma of ambient gas origin.

A developing supercritical collisionless shock propagating in a homogeneously magnetized plasma of ambient gas origin having higher uniformity than the previous experiments is formed by using high-power laser experiment. The ambient plasma is not contaminated by the plasma produced in the early time after the laser shot. While the observed developing shock does not have stationary downstream structure, it possesses some characteristics of a magnetized supercritical shock, which are supported by a one-dimensional full particle-in-cell simulation taking the effect of finite time of laser-target interaction into account.

Review and pooled analysis of studies on MTHFR C677T polymorphism and esophageal cancer.

Esophageal cancer has been associated with tobacco and alcohol consumption, gastric reflux, exposure to nitrosamines from food or other environmental sources, and diets lacking folate. Susceptibility to esophageal cancer may be modified by functional polymorphisms in genes along the folate metabolic pathway, such as methylenetetrahydrofolate reductase (MTHFR). The C677T polymorphism is the most common functional variant, leading to a reduction in enzyme activity. We report a pooled analysis of 5 studies on the association of MTHFR C677T polymorphism and esophageal cancer, including 725 cases and 1531 controls. A significant association between the MTHFR 677 TT genotype and esophageal cancer was observed (OR=2.63, 95% CI: 1.75-3.94), although there was significant heterogeneity between studies. A sensitivity analysis excluded one study; the association between TT genotype and esophageal cancer was still present, although of reduced magnitude (OR=1.57, 95% CI: 0.96-2.56). A significant interaction between smoking and TT genotype on esophageal cancer risk was observed, while no interaction was observed between alcohol consumption and genotype.

Microscale multiple scattering of coherent surface acoustic wave packets probed with gigahertz time-reversal acoustics.

The multiple scattering of coherent surface acoustic wave packets in a microstructure is studied using an ultrafast optical technique. By recording a set of acoustic transfer functions, we show that it is possible to implement time-reversal acoustics and refocus the wave packets up to the GHz range, two orders of magnitude higher than usual. Many applications in time-reversal acoustics are thus transposable to correspondingly smaller structures, opening the way to efficient nondestructive characterization and manipulation of multiple scattering on the microscale.

Short-term breast-feeding may reduce the risk of vertical transmission of HTLV-I. The Tsushima ATL Study Group.

To establish a desirable preventive measure against mother-to-child transmission of HTLV-I through breast milk, we conducted a prospective study to investigate the seroconversion rate among children born to HTLV-I carrier mothers on two highly HTLV-I-endemic islands where 8% of pregnant women carry HTLV-I. Between 1985 to 1991, 428 pregnant women were found to be positive against anti-HTLV-I antibody and were advised not to breast-feed their newborn babies. Among them, 212 women (50%) accepted this advice and the other mothers proceeded to breast-feed. Results were obtained from 277 children born to HTLV-I carrier mothers and were followed up until more than 30 months of age. When the seroconversion rate was analyzed by feeding manner, short-term breast-feeders (< or = 6 months) showed a statistically significant lower seroconversion rate than long-term breast-feeders (2/51; 3.9% vs. 13/64; 20.3%, p < 0.05). On the other hand, four out of 162 bottle-fed children (2.5%) became positive. It is hypothesized that maternal HTLV-I antibody may protect babies from HTLV-I infection through breast milk during the first 6 months.

Association of Ile462Val (Exon 7) polymorphism of cytochrome P450 IA1 with lung cancer in the Asian population: further evidence from a case-control study in Okinawa.

Okinawa, a group of islands that lie between the East China Sea and the Pacific Ocean, 2000 km south of the Japanese main islands, has a different profile of diseases, ethnicities, and cultures than does the rest of Japan. We examined an Ile462Val polymorphism (CYP1A1*2 allele) of cytochrome P450 IA1 in a hospital-based case-control study of lung cancer patients (247 cases and 185 controls) in Okinawa to ascertain the association of this variant with lung cancer. In addition, the distribution of this genotype was studied in populations from different areas of Japan, including Tokyo (n = 69) and Iwate (northern part of Japan; n = 81), as well as in a Chinese group from the Jiangsu province (n = 39) and in an Australian Caucasian group (n = 146). Genotype frequency in controls was not significantly different from area to area in Japan. In Okinawa, however, the genotype encoding Val/Val was associated with a significantly higher risk of lung cancer (odds ratio = 3.32, P = 0.013), especially of squamous cell carcinoma and small cell carcinoma (odds ratio = 4.85 and 9.35, respectively). The Val-encoding allele was less frequent in the Chinese population and was rare in Australian Caucasians. Thus, this study gives support to the value of the cytochrome P450 IA1 Ile462Val polymorphism as a practical high-risk marker of lung cancer in populations, especially those in southeast Asia, in which this variant is more common.

Smoking and lung cancer risk in American and Japanese men: an international case-control study.

Rates of lung cancer in American men have greatly exceeded those in Japanese men for several decades despite the higher smoking prevalence in Japanese men. It is not known whether the relative risk of lung cancer associated with cigarette smoking is lower in Japanese men than American men and whether these risks vary by the amount and duration of smoking. To estimate smoking-specific relative risks for lung cancer in men, a multicentric case-control study was carried out in New York City, Washington, DC, and Nagoya, Japan from 1992 to 1998. A total of 371 cases and 373 age-matched controls were interviewed in United States hospitals and 410 cases and 252 hospital controls in Japanese hospitals; 411 Japanese age-matched healthy controls were also randomly selected from electoral rolls. The odds ratio (OR) for lung cancer in current United States smokers relative to nonsmokers was 40.4 [95% confidence interval (CI) = 21.8-79.6], which was >10 times higher than the OR of 3.5 for current smokers in Japanese relative to hospital controls (95% CI = 1.6-7.5) and six times higher than in Japanese relative to community controls (OR = 6.3; 95% CI = 3.7-10.9). There were no substantial differences in the mean number of years of smoking or average daily number of cigarettes smoked between United States and Japanese cases or between United States and Japanese controls, but American cases began smoking on average 2.5 years earlier than Japanese cases. The risk of lung cancer associated with cigarette smoking was substantially higher in United States than in Japanese males, consistent with population-based statistics on smoking prevalence and lung cancer incidence. Possible explanations for this difference in risk include a more toxic cigarette formulation of American manufactured cigarettes as evidenced by higher concentrations of tobacco-specific nitrosamines in both tobacco and mainstream smoke, the much wider use of activated charcoal in the filters of Japanese than in American cigarettes, as well as documented differences in genetic susceptibility and lifestyle factors other than smoking.

hOGG1 Ser326Cys polymorphism and lung cancer susceptibility.

The human homologue of the yeast OGG1 gene, hOGG1, has been cloned, and its genetic structure has been determined. Several polymorphisms in the hOGG1 gene were detected in the Japanese populations, and among them, the Ser-Cys polymorphism at codon 326 has been shown to have a functional difference in complementation of mutant Escherichia coli that is defective in the repair of 8-hydroxyguanine. Activity in the repair of 8-hydroxyguanine is greater in hOGG1-Ser326 protein than in hOGG1(326) protein. Because many environmental carcinogens produce 8-hydroxyguanine residue and mismatching to this modified base potentially causes oncogenic mutations, the capacity to repair these lesions can be involved in cancer susceptibility in human beings. We, therefore, examined allele distributions of the Ser326Cys polymorphism in a case-control study of male lung cancer in Okinawa. The analyses based on 241 cases and 197 hospital controls disclosed the following findings. (a) Those with the Cys/Cys genotype were at an increased risk of squamous cell carcinoma and nonadenocarcinoma compared to those with the Ser/Cys and those with the Ser/Ser genotypes combined. The odds ratios adjusted for age and smoking history were 3.01 (95% confidence interval, 1.33-6.83) and 2.18 (95% confidence interval, 1.05-4.54), respectively. (b) The odds ratios for other histological subtypes of lung cancer or those in total were not significant. Those for Cys/Cys or Ser/Cys genotype against Ser/Ser did not reach statistical significance in any cell type. (c) The distributions of this polymorphism varied for different populations (Chinese, Japanese, Micronesians, Melanesians, Hungarians, and Australian Caucasians), with much less prevalence of Cys allele in the latter three populations. Although our sample size was limited, these results indicate that the Ser326Cys variant may be related to squamous cell lung cancer susceptibility. The Cys/Cys genotype appears to be more susceptible to squamous cell carcinoma, although the risk is less than that previously reported to be associated with the CYP1A1 gene. Further studies are needed to assess the importance of the interpopulation variation to cancer susceptibility.

Case-control studies: matched controls or all available controls?

In order to realize the variation in the estimate of the odds ratio from case-control studies, results from individually matched sampling were compared with those from the analysis based on a large number of controls. The subjects were selected from those who visited Aichi Cancer Center Hospital from 1988 to 1990. Cases consisted of 251 male lung cancer patients aged 40-79 years. Age and year of visit matched controls were sampled independently 100 times and 5000 times from non-cancer male outpatients (cases to controls ratio: 1:1, 1:2, 1:3, and 1:4). As unmatched controls, all male non-cancer outpatients aged 40-79 years (4100 patients) were used. The smoking habit was adopted as an exposure variable. As logically expected, analysis based on 4100 male controls gave a steadier estimate than the matched analyses examined here, indicating that a matched sampling is not recommended when a large number of controls are available.

Epidemiological features of first-visit outpatients in Japan: comparison with general population and variation by sex, age, and season.

To evaluate the methodological issues in using first-visit outpatients as controls in epidemiological studies, the features of general lifestyles of non-cancer outpatients at Aichi Cancer Center Hospital (ACCH) were compared with those of the general population, and their variation by sex, age, and season was determined by using a self-administered questionnaire. The study included 1231 subjects randomly selected from the Nagoya electoral roll (CRG), and three groups of non-cancer ACCH outpatients living in Nagoya; 800 from the period September to December 1992 (OPG1), 2326 from January to December 1992 (OPG2), and 12,243 from January 1991 to December 1992 (OPG3). In the younger age group, the proportion of current smokers was higher in the CRG than in the OPGs. In the older age groups, the proportion of those who consumed fresh vegetables and fruit everyday was higher in the OPGs than in the CRG. For other items, the features of the OPGs were not significantly different from those of the CRG. Among the OPG3, there were differences in the features of general lifestyles between sexes and consumption of several food items varied with age. Seasonal variation, however, was only observed in the specific food items where supply varied seasonally. It was concluded that, with due consideration of age, sex, and season in the analysis, it is feasible to use non-cancer outpatients as controls in epidemiological studies.

Fish consumption and colorectal cancer: a case-reference study in Japan.

Several clinical studies have suggested that supplementation with fish oils can suppress the proliferation of colorectal mucosa and therefore inhibit the development of colorectal cancer. However, epidemiological evidence concerning fish consumption and risk is inconsistent and limited. To clarify the association between intake of fish and the likelihood of developing colorectal cancer, we conducted a large sample size case-reference study with 928 cases of colon cancer, 622 of rectal cancer and 46886 cancer-free outpatient references aged 40-79 years. The data showed frequent raw/cooked fish intake to be associated with decreased odds ratio (OR) 0.68 with 95% confidence interval (CI) 0.47-0.99 for male colon cancer, especially for males aged over 60 years, smokers and frequent meat eaters. A marginal decrease in the OR (OR 0.58, 95% CI 0.31-1.07) was also detected for female rectal cancer, especially in the regular physical exercise subgroup. However, frequent dried/salted fish intake was found to be associated with increased OR in females younger than 60 years old and alcohol drinkers. Although there is some possible bias in epidemiological studies, the results suggest that frequent raw/cooked fish intake may decrease the risk while dried/salted fish, in contrast, may exert a detrimental effect.

[Risk of death by health habit index from a cohort study among the residents of a rural area in Aichi, Japan].

To clarify the validity of the health habit index, we evaluated risk of death by health habit index in residents in Aichi Prefecture. Subjects were 7,662 residents aged 40-79 years living in a rural area of Aichi Prefecture who responded to a questionnaire in 1988, that included 12 health habit items on diet, physical activity, rest, mental health, smoking, drinking and regular health check. Data on death and migration in this cohort group was collected from 1990 to 1997. The risk ratios (RRs) of death for all causes, cancer and cardiovascular diseases were estimated by Cox's proportional hazard model. The number of all causes of death, cancer and cardiovascular diseases was 650, 240 and 197, respectively. Proper health habits of adequate but not over eating, regular physical activity, properly managing stress, non-smoking or smoking cessation for one year or more and regular health examinations in men and regular physical activity and non-smoking in women related to lower age-adjusted RR of death for all causes, while smoking cessation of less than one year in men with increased RR. Lower RR of cancer was observed for non-smoking men, and for women who occasionally have enough sleep. Proper health habits on adequate but not overeating, enjoying mealtime, regular physical activity, properly managing stress, moderate drinking (< 2 "go"/day) or occasional heavy drinking and regular health examinations related to lower RR of cardiovascular diseases in men, while regular physical activity related to lower RR in women. Multivariate analysis for the RR of death for all causes showed similar results, except higher RR in the men who avoided excess salt consumption, and decreased RR in the women who occasionally have enough sleep. In conclusion, the present study suggested that regular physical activity is associated with decreased risk from death for all causes, especially for cardiovascular diseases. Health habit index in the present study included various items with or without association to risk for death. It is important to apply this index to health promotion on the basis of its specific characteristic.

[Survival factors in healthy aging among rural Japanese residents of Aichi].

To investigate survival factors in healthy aging among rural Japanese elderly residents, a nested case-control study was conducted. Subjects who answered questionnaires in 1985 were followed for 10 years. Cases comprised 124 men and 109 women who, in 1995, were 75 years old or over, and whose activities of daily living were active enough to cope for themselves. Controls were selected from subjects who died between 1987 and 1994. One control per case was randomly selected, and matched to each case for sex and birth-year (+/- 2 years). The survival odds ratio (sOR) was calculated by using a conditional multiple logistic regression model. An sOR greater than 1.0 was observed for frequent intake of eggs, regular daily routine, adaptability to changes, leisure time exercise and a health examination at least once within 3 years. In both men and women present or past history of heart disease, cerebrovascular disease and diabetes, family history of hypertension, and in women, smoking were negatively associated with survival. By multivariate analysis, adaptability to change in men, and regular daily routine and health examinations in women were positively associated to survival. Smoking and history of chronic disease were negatively associated with survival, in both men and women. In conclusion, it is suggested that psychological factors and recent health examinations were positively associated to survival in healthy aging, and habitual smoking and chronic disease contributed negatively to survival. These results require further careful evaluation to determine whether the factors are associated with cause or effect.

[Association between the interleukin 1B (C-31T) polymorphism and Helicobacter pylori infection in health checkup examinees].

PURPOSE: Associations between Helicobacter pylori (HP) infection and lifestyle factors have been demonstrated by several studies, but there are very few reports on links with host factors, especially concerning genetic polymorphisms for inhabitants of large city. The present investigation was conducted to determine the HP infection rate with reference to the Interleukin-1 beta gene (IL-1B) polymorphism and assess the interactions with smoking reported for outpatients. METHOD: The subjects were 468 participants in a health-check-up program of law of health for aged conducted by Nagoya Nishi Health Center. The participants were asked to permit use of their residual blood drawn during a health-check-up program and written informed consent was obtained for gene polymorphism tests. Data on smoking habit were obtained by self-administered questionnaire. The IL-1B C-to-T polymorphism at -31 was genotyped by PCR-CTPP (polymerase chain reaction with confronting two-pair primers) and an anti-HP IgG antibody test was used for detecting HP infection. Differences in values were assessed by a chi 2 test. An unconditional logistic model was applied for estimating odds ratios with the computer program STATA Version 6. This study was approved by the Ethical Committee at Aichi Cancer Center in 2000 before it was commenced (Ethical Committee Approval Number 11-12) RESULTS: The HP infection rate was 52.6% (61/116) for the C/C genotype of IL-1B-31, 48.6% (89/183) for the C/T, and 63.2% (103/163) for T/T; the difference were not statistically significant. However, when non-current smokers were excluded, the rate were 47.8% (11/23), 52.9% (18/34), and 72.7% (16/22), respectively, indicating the T/T genotype to have a higher infection rate. The age-sex-smoking adjusted odds ratio (OR) relative to the C/C genotype were 0.97 (95% confidence interval, 0.59-1.57) for the T/C genotype and 1.73 (1.04-2.87) for the T/T genotype. Among current and former smokers the age-sex adjusted OR were 1.68 (0.50-5.71) for the T/C genotype and 5.29 (1.11-25.1) for the T/T genotype, suggesting a effect of this polymorphism prominent in smokers. CONCLUSION: An association between the IL-1B-31 polymorphism and persistent HP infection was observed for inhabitants with a smoking habit, indicating that this polymorphism is one genetic trait conferring an increased likelihood of persistent HP infection.

[Development and evaluation of a QOL questionnaire for elderly subject living in a community].

A comprehensive, basic and simple QOL questionnaire for elderly subjects living in a community was developed, and its validity and reliability were examined. The subjects were 2944 individuals of 65 years or older living in 5 areas of metropolitan Tokyo and in a town of Aichi Prefecture. The QOL questionnaire with 19 questions was developed based on the component of QOL by Lawton and concept of QOL by Koyano. The questionnaire consisted of 6 subscales (daily activity, satisfaction with health, satisfaction with human support, satisfaction with economic state, symptom of depression and positive mental attitude). Factor analysis revealed that the 19 questions could be clearly separated into 6 components in Tokyo and Aichi districts with total variances of 70.8% and 78.4%, respectively. Scores of daily activity and positive mental attitude were significantly lower with older subjects in both men and women. However, scores for other subscales did not differ with age. Primary factors which are considered to affect QOL were compared with the 6 QOL subscales of this study. Being an outpatient had a significant relation to daily activity and satisfaction with health, presence of a spouse to satisfaction with human support, depressive state, positive mental attitude and possession of ones own room to satisfaction with economical state, and belief in religion to positive mental attitude. The results suggest that the present questionnaire include the basic components necessary for evaluation of QOL in elderly subjects living in a community. Further research is required to examine the validity of this questionnaire with correction of questions.

[A case of vesicovaginal fistula with vaginal stone].

The patient, a 51-year-old woman developed urinary incontinence after an abdominal hysterectomy 3 years earlier. She was referred to our hospital complaining of urine leakage from her vagina after spontaneous passage of a stone. Drip infusion pyelography and cystography demonstrated a vesicovaginal fistula. She underwent repair of the fistula with an abdominal procedure. The stone was composed of magnesium ammonium phosphate.

[Bladder substitution using ileal neobladder after total cystectomy: report of three cases].

We constructed an ileal neobladder in three patients using Hautmann's technique. The patients were men 51 and 67 years old with invasive bladder cancer and a 45-year-old woman with intractable hemorrhagic cystitis induced by cyclophosphamide. The urethral catheter was removed on the 21st postoperative day. At 2 to 5 months following operation, 3 patients had a vesical capacity of 270 to 500 ml and the maximum volume of urine excreted at one voiding was 130 ml to 400 ml. Voiding cystography disclosed no vesico-ureteral reflux. Two patients required abdominal straining at urination and another patient complained of a slight degree of nocturnal incontinence. Intravesical pressure was retained below 10 cm in hydrostatic height in two patients. On the other hand, it gradually increased as the neobladder was extended in another one. No uninhibited contraction was demonstrated by cystometric examination. The serum chloride level indicated almost the maximum normal value in all patients. Neither hydronephrosis nor residual urine was seen on drip infusion pyelography. The postoperative results indicate that the ileal neobladder using Hautmann's technique may become a very useful way to reconstruct the urinary tract.

[A case of infected renal cyst extending to leg abscess].

A 45-year-old woman was referred to our hospital with the chief complaint of left flank pain, left leg pain and loss of appetite. Computed tomography scan and magnetic resonance imaging demonstrated a large cystic mass in the left kidney, which we diagnosed as an infected renal cyst. Under ultrasonic guidance, percutaneous puncture and drainage of the renal cyst were performed. After her leg pain worsened, computed tomography revealed abscesses in the left leg, suggesting an infected renal cyst extending to the leg through the obturator foramen. Under general anesthesia, incision and drainage were performed. Cultures from the cyst and abscess fluid showed Klebsiella pneumoniae. Our case is the 82nd case of an infected renal cyst in the Japanese literature.