Biomedical subjects

K Tajima

Publications and source records attributed to K Tajima.

At least 73 records · Page 4Linked to original sources

PubMed2001

Dietary protective and risk factors for esophageal and stomach cancers in a low-epidemic area for stomach cancer in Jiangsu Province, China: comparison with those in a high-epidemic area.

Comparative epidemiological studies with ecological and case-control approaches in high- and low-epidemic areas of China have provided us with much evidence with regard to risk and benefit in the environment. To clarify how dietary factors are involved in esophageal and stomach cancer development, we performed a case-control study in a low-epidemic area, and compared the findings with those obtained earlier for a high-epidemic area for stomach cancer in the same Jiangsu Province, China. We recruited 199 and 187 cases with esophageal and stomach cancers, respectively, and 333 population-based common controls. Odds ratios (ORs) for esophageal and stomach cancers were calculated with adjustment for potential confounding factors, using an unconditional logistic model. Current and former smoking elevated the OR for esophageal cancer, along with high intake of pickled vegetables and broiled meat, while decreased ORs were observed for frequently consumed raw vegetables and garlic. With regard to stomach cancer, ORs were increased with frequent consumption of salty fish, leftover gruel, and broiled meat, and lowered by snap bean consumption. The present risk factors were common to the previously obtained results in the high-epidemic area, and similarly distributed in each general population. While more protective factors were observed in the high-epidemic area, their penetrance was much greater in the low-epidemic area. The present study thus suggests that frequent vegetable and garlic consumption contributes to low mortality rates for esophageal and stomach cancers in a low-epidemic area, counteracting similar exposure levels for risk factors as in the high-epidemic area.

Adult↗

PubMed2001

Diet-dependent shifts in the bacterial population of the rumen revealed with real-time PCR.

A set of PCR primers was designed and validated for specific detection and quantification of Prevotella ruminicola, Prevotella albensis, Prevotella bryantii, Fibrobacter succinogenes, Selenomonas ruminantium-Mitsuokella multiacida, Streptococcus bovis, Ruminococcus flavefaciens, Ruminobacter amylophilus, Eubacterium ruminantium, Treponema bryantii, Succinivibrio dextrinosolvens, and Anaerovibrio lipolytica. By using these primers and the real-time PCR technique, the corresponding species in the rumens of cows for which the diet was switched from hay to grain were quantitatively monitored. The dynamics of two fibrolytic bacteria, F. succinogenes and R. flavefaciens, were in agreement with those of earlier, culture-based experiments. The quantity of F. succinogenes DNA, predominant in animals on the hay diet, fell 20-fold on the third day of the switch to a grain diet and further declined on day 28, with a 57-fold reduction in DNA. The R. flavefaciens DNA concentration on day 3 declined to approximately 10% of its initial value in animals on the hay diet and remained at this level on day 28. During the transition period (day 3), the quantities of two ruminal prevotella DNAs increased considerably: that of P. ruminicola increased 7-fold and that of P. bryantii increased 263-fold. On day 28, the quantity of P. ruminicola DNA decreased 3-fold, while P. bryantii DNA was still elevated 10-fold in comparison with the level found in animals on the initial hay diet. The DNA specific for another xylanolytic bacterium, E. ruminantium, dropped 14-fold during the diet switch and was maintained at this level on day 28. The concentration of a rumen spirochete, T. bryantii, decreased less profoundly and stabilized with a sevenfold decline by day 28. The variations in A. lipolytica DNA were not statistically significant. After an initial slight increase in S. dextrinosolvens DNA on day 3, this DNA was not detected at the end of the experiment. S. bovis DNA displayed a 67-fold increase during the transition period on day 3. However, on day 28, it actually declined in comparison with the level in animals on the hay ration. The amount of S. ruminantium-M. multiacida DNA also increased eightfold following the diet switch, but stabilized with only a twofold increase on day 28. The real-time PCR technique also uncovered differential amplification of rumen bacterial templates with the set of universal bacterial primers. This observation may explain why some predominant rumen bacteria have not been detected in PCR-generated 16S ribosomal DNA libraries.

Animal Feed↗

PubMed2001

Beta-globin gene haplotype characteristics of Colombian Amerinds in South America.

Haplotypes and subhaplotypes in the beta-globin gene cluster were identified in 146 and 156 chromosomes, respectively, of three tribes of Colombian Amerinds. Subhaplotype [+----] was a major one in Colombian Amerinds as in most human ethnic groups except Africans. A major subhaplotype [----+] in Africans was observed in only one chromosome. The framework 2 frequencies were very low (0.018-0.067). Haplotype [+----++], which is a major one in Europeans, but not in Asians, and [+-----+], which is a major one in Asians, but not in Europeans, were two major haplotypes. Subhaplotype data showed the closest genetic affinities between Colombian Amerinds and Polynesians, Micronesians, and Asians, but the haplotype data did not necessarily support this.

Colombia↗

PubMed2001

Glucocorticoids protect against apoptosis induced by serum deprivation, cyclic adenosine 3',5'-monophosphate and p53 activation in immortalized human granulosa cells: involvement of Bcl-2.

Glucocorticoid hormones are known to enhance gonadotropin/cAMP-induced steroidogenesis in rat and human granulosa cells. As glucocorticoids induce apoptosis in numerous cell types, we investigated the role of glucocorticoids in the control of apoptosis in immortalized human granulosa cells (HO-23) transfected with a temperature-sensitive mutant of p53 (Val(135)). When HO-23 were incubated with forskolin in the presence or absence of dexamethasone (Dex) at 32 or 37 C, progesterone production was higher by 4- and 8-fold in the presence of Dex at 37 or 32 C, respectively (P: < 0. 01). The expression of adrenodoxin (ADX), which is an intrinsic part of the cytochrome P450 side-chain cleavage enzyme system, remained the same in the presence or absence of Dex in forskolin-stimulated cells. Dex reduced apoptosis (to 33% of control) in cultures after activation of p53 by shifting the temperature from 37 to 32 C. Moreover, Dex suppressed apoptosis induced by serum deprivation (to 40% of control) or forskolin stimulation (to 28% and 40% at 37 and at 32 C, respectively). The protective effect of Dex on cAMP-, p53-, and serum deprivation-induced apoptosis was confirmed by both 4',6-diamido-2-phenylindole hydrochloride DNA staining and terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling with an ED(50) of 7 nM Dex. Hydrocortisone showed a similar antiapoptotic effect. The protective effect of glucocorticoids against apoptosis was completely abolished by RU486 when cells were coincubated with 10 nM Dex and 10-100 nM RU486. The protection against apoptosis by glucocorticoid involved a sharp elevation in intracellular levels of Bcl-2 (3-7.6 fold; P: < 0.01). In contrast to the effect of Dex in the prevention of apoptosis in HO-23 granulosa cells, Dex dramatically stimulated apoptosis by 3-fold in LTR-6 myeloid leukemia cells expressing the same temperature-sensitive mutant (Val(135) p53) and the same amount of glucocorticoid receptor-alpha. Forskolin did not stimulate apoptosis when incubated with these cells. However, it augmented by 1.2-fold the p53-induced apoptosis in cells shifted from 37 to 32 C. Dex further enhanced apoptosis by 1.9-fold in p53-activated cultures (32 C). Incubation of the cells with Dex dramatically reduced Bcl-2 levels to 15% of control at 37 C (P: < 0.01) or 32 C in the presence or absence of forskolin (P: < 0.01). Our data suggest that glucocorticoids exert a protective effect against induced apoptosis in immortalized granulosa cells and a stimulatory effect on apoptosis in myeloid leukemia cells. Moreover, modulation of Bcl-2 levels plays an important role in mediating the glucocorticoid effect on cell survival. The opposite effect of glucocorticoids on Bcl-2 levels in the two cell lines may be due to the different ontogeneses of the two cell types: epithelial for granulosa cells vs. mesenchymal for myeloid cells studied in the present work.

Apoptosis↗

PubMed2001

Apoptosis of granulosa cells and female infertility in achondroplastic mice expressing mutant fibroblast growth factor receptor 3G374R.

Fibroblast growth factors play an important role in the control of ovarian folliculogenesis, but the complete repertoire of ovarian receptors which can transduce the fibroblast growth factor signals and their precise localization in the ovary have not yet been characterized. The most common form of inherited human dwarfism results from a point mutation in the transmembrane region of fibroblast growth factor receptor 3. A mouse model for achondroplasia was generated by introducing the human mutation (glycine 380-arginine) into the mouse fibroblast growth factor receptor 3 (G374R) by a "knock-in" approach using gene targeting leading to a constitutively active receptor. This resulted in the development of dwarf mice that share many features with human achondroplasia. Here we report that female (fibroblast growth factor receptor 3 G374R) dwarf mice become infertile. While no significant changes were observed in the anatomical and histological appearance of ovaries of 3-wk-old dwarf mice, a dramatic difference was observed in ovaries of 3-month-old mice. The normal ovary consists mainly of healthy corpora lutea and follicles at different stages of development, whereas the ovaries of the dwarf mice remain small and contain mainly follicles with a progressive apoptosis in the granulosa cells, and no corpora lutea could be observed. The levels of LH, FSH, and progesterone were lower by 72.3%, 38.0%, and 40.0%, respectively, in the blood of the dwarf mice compared with normal mice, and the total bioactivity of pituitary FSH and LH was lower by 65.6% and 79.6%, respectively, in the dwarf mice compared with normal mice. However treatment with PMSG and human CG of the dwarf mice led to rapid follicular development and formation of corpora lutea. Interestingly, the expression of the tumor suppressor gene p53 was increased dramatically in ovaries of the dwarf mice. The presence of the fibroblast growth factor receptor 3 cellular receptors in both normal and dwarf animals was demonstrated by Western blot and immunostaining. However, the distribution of the fibroblast growth factor receptors in the two strains shows significant differences. In the normal ovaries fibroblast growth factor receptor 3 was homogeneously distributed on the cell membrane of the granulosa cells and was absent in theca as well as corpora lutea cells, whereas in dwarf mice ovaries it was highly clustered on granulosa cells and very often appears in endocytic vesicles. Aged oocytes were more frequently observed in preantral follicles of ovaries of the dwarf mice. Nevertheless, oocytes isolated from antral follicles resume their meiotic division at a high percentage, similar to oocytes obtained from normal ovaries. The results imply fibroblast growth factor receptor 3 involvement in the control of follicular development through regulation of granulosa cell growth and differentiation, and that unovulation in the dwarf mice could be overcome in part by administration of exogenous gonadotropins. Moreover, it is suggested that the infertile phenotype is partially due to defects in the pituitary-gonadal axis.

Achondroplasia↗

PubMed2001

Flagellin as a biomarker for Bacillus subtilis strains; application to the DB9011 strain and the study of interspecific diversity in amino-acid sequences.

Polymerase chain reaction (PCR) for the flagellin central domain coding region (FCD-PCR) was applied to the detection and discrimination of Bacillus subtilis DB9011, a strain with useful functions in agriculture. Cross-reactions were observed in 4 B. subtilis strains with similar flagellin genes (hag). Alignment of partial amino-acid sequences of flagellin and the results of PCR for the 16S/23S rRNA spacer in 11 B. subtilis strains suggested the presence of a group including strains with antifungal activity (DB9011 and others).

Amino Acid Sequence↗

PubMed2001

Possible risk reduction in esophageal cancer associated with MPO -463 A allele.

Myeloperoxidase (MPO), an enzyme found in lysosomes of phagocytes, causes hydroxy radicals linked to DNA damage and activation of smoking related carcinogens. A -463 G/A polymorphism in the promoter region of the MPO gene results in reduced gene expression, which would imply lower susceptibility of esophageal cancer in mutant carriers. We conducted case-control study to test this hypothesis. Cases were 91 patients with esophageal cancer and controls were 241 non-cancer outpatients. MPO genotypes were examined by PCR-RFLP. The allele frequency for MPO -463A was found to be 8.2% for cases and 10.5% for controls. The age, sex, smoking and drinking status adjusted odds ratio for all subjects for MPO -463 GG/GA as compared to the AA was 0.61 (95% CI: 0.28-1.32). The adjusted odds ratio for the GG/GA genotype was significantly low (0.15; 0.03-0.76, P=0.022) for those aged 61 years or older who had a significantly higher odds ratio for smoking than younger subjects. No difference was observed in disease risk when prevalent and incident cases were compared. Although there are limitations for interpretation of this study because of prevalent case-control study and partial statistical significance, these results suggest that MPO -463 A allele reduce the risk of esophageal cancer.

Adult↗

PubMed2001

Smoking habit and interleukin lB C-31T polymorphism.

Recent studies suggest that smoking habit may relate to genetic traits. This study examines the association with a polymorphism (C-31T) of interleukin 1B (IL-1B), which encodes IL-1beta, a multifunctional pro-inflammatory cytokine. Since the T allele makes a TATA box, the allele is thought to be responsible for a higher potency of IL-1B expression, indicating that individuals harboring the T allele are prone to inflammation. The study subjects were two different populations; 241 non-cancer outpatients (118 males and 123 females) at a cancer hospital and 462 examinees (127 males and 335 females) of a health checkup program provided by a local government. Current smokers were 36.4% for the male outpatients, 9.8% for the female outpatients, 38.6% for the male examinees, and 5.6% for the female examinees. The sex-age-adjusted odds ratios of current smokers were calculated for the genotypes with the T allele relative to the CC genotype by an unconditional logistic model. The estimate was 0.45 (95% confidence interval, 0.21-0.97) for the outpatients, and 0.83 (0.42-1.61) for the examinees. Although not significant for the examinees, the observed associations suggest that this polymorphism may influence smoking behavior through an inflammatory response of the respiratory tract to cigarette smoke.

Adult↗

PubMed2001

Expression of heparanase, Mdm2, and erbB2 in ovarian cancer.

Ovarian cancer is the most lethal of gynecological malignancies. Yet early diagnosis and prognosis are far from being satisfactory. Degradation of heparan sulfate proteoglycans by heparanase appears to play an important role in the invasiveness of tumor cells through the basement membrane and into the extracellular matrix. Recent cloning of the heparanase gene and generation of monoclonal antibodies against the enzyme permit to examine tumor cell expression of the enzyme. The aim of the present study was to assess heparanase activity and localization in various subtypes of epithelial ovarian cancer in correlation with oncogene expression. Histologically confirmed malignant ovarian tissue from ten women and tissue from 2 benign ovarian tumors and 4 normal ovaries were assessed for heparanase presence, activity and localization, incidence of apoptosis and expression of the oncogenes erbB2 and Mdm2. Heparanase immunohistostaining and activity were present in mucinous carcinomas and were more intense than in endometrioid and in serous carcinomas. The lowest activity was observed in benign ovarian tumors and normal ovaries. In ovarian carcinomas the enzyme was intensely concentrated in the cytoplasm of the cancerous cells. In contrast, in normal ovaries and benign tumors the enzyme was predominantly localized in endothelial cells lining blood capillaries. The rate of apoptosis was considerably higher in mucinous and endometrioid carcinomas, and was lower in serous and primary peritoneal carcinomas. Extremely high concentration of heparanase was often demonstrated in apoptotic cells. Endometrioid and serous carcinomas showed high expression of Mdm2 and erbB2 while mucinous carcinomas showed low expression. In benign ovarian tumors and normal ovaries the expression of both oncoproteins was extremely low. In conclusion ovarian carcinomas demonstrate higher levels of heparanase than benign tumors and normal ovaries suggesting that the enzyme may play an important role in metastatic spread of the cancerous cells. Apoptosis may be a significant part of the mechanism of the enzyme release into the extracellular space. Although heparanase activity seems to play an essential role in tumor progression, expression of oncogenes, such as erbB2 and Mdm2 seems to play the dominant role in the development of ovarian cancer.

Adenocarcinoma, Mucinous↗

PubMed2001

Application of electrolyzed acid water to sterilization of denture base part 1. Examination of sterilization effects on resin plate.

Bactericidal activities of electrolyzed strong and weak acid waters for acrylic denture base resin were evaluated in order to discuss the applicability of these waters for sterilization of denture base. Only 1-minute immersion in the electrolyzed strong or weak acid water could completely eliminate the attached bacteria, Staphylococcus aureus 209P, on the resin plate. When the resin was relined with tissue conditioner, 5-minute immersion or 1- to 2-minute ultrasonic cleaning reduced the number of the bacteria from 10(5)/cm2 level to 10(1)/cm2 and no surviving bacteria could be detected after 10-minute treatment. These findings suggest that both the electrolyzed strong and weak acid waters are well applicable to the disinfectant for acrylic denture base showing excellent bactericidal activities in a significantly shorter treatment as compared with the conventional denture cleaning.

Acrylic Resins↗

PubMed2001

[Rupture of renal pelvis due to urolithiasis: report of two cases].

Two cases of renal pelvis rupture caused by urolithiasis are reported. The first case was in a 62-year-old male who had left flank pain. Urological examination including drip infusion pyelography (DIP) and abdominal computed tomography (CT) revealed a spontaneous rupture of the left renal pelvis. The rupture was assumed to have been caused by a small ureteral stone. The stone passed spontaneously, and the extravasation disappeared with conservative therapy. The second case was in a 84-year-old male who was admitted with high fever. Urological examination including DIP and abdominal CT showed a suspected rupture of the left renal pelvis due to a renal stone at the ureteropelvic junction. Percutaneous nephrostomy was performed and antegrade pyelography showed extravasation from the left renal pelvis. Extravasation disappeared on the 12th postoperative day. Extracorporeal shock wave lithotripsy was performed three times. The renal stone was completely discharged and the nephrostomy tube was removed successfully.

Aged↗

PubMed2001

[Epidemiology of lymphoid and hematopoietic malignancies in Japan].

In general, the incidence and mortality rates for lymphoid and hematopoietic malignancies in Oriental countries, including Japan, are lower than in Western Europe and the U.S. However, those of lymphoid malignancies (ML) are clearly increasing in Japan, especially in the older generations. The main cause of the recent increment might be explained by compensation for risk reduction of infectious diseases in the old generations, so that their life span is extended rather than increment in exposure to specific risk factors. With regard to change in diagnostic criteria for ML, the geographical distribution of ML death rates by subtype shows variation over the last 20 years. In Japan, ML is more prevalent in southwestern districts, attributed to ATL caused by HTLV-I, and this high incidence of ATL should disappear with the HTLV-I eradication in the future. On the other hand, further diagnostic techniques might be developed and it is conceivable that a unique geographical distribution of new subtypes of lymphoid and hematopoietic malignancies may thereby be generated.

Adolescent↗

PubMed2001

[Pulmonary edema in a child following laryngospasm triggered by a laryngeal mask airway during emergence from anesthesia].

A 9-year-old boy underwent biopsy of the tumor at the external auditory meatus under general anesthesia with a laryngeal mask airway(LMA). During emergence from anesthesia, laryngospasm with marked inspiratory effort and cyanosis occurred. The LMA was removed and the patient was orotracheally intubated following vecuronium administration. In spite of controlled ventilation with 100% oxygen, oxygen saturation remained at low 90s and pink frothy sputum appeared in the tracheal tube. We suspected negative pressure pulmonary edema and treated him with mechanical ventilation with positive end-expiratory pressure. Seventeen hours later the pink frothy sputum decreased and he was extubated. Laryngospasm during emergence from anesthesia with an LMA can induce negative pressure pulmonary edema, especially in pediatric patients.

Anesthesia Recovery Period↗

PubMed2001

No substantial difference in genotype frequencies of interleukin and myeloperoxidase polymorphisms between malignant lymphoma patients and non-cancer controls.

BACKGROUND AND OBJECTIVES: The functional polymorphisms regulating immunologic responses may influence the proliferation or suppression of malignant lymphoma. We examined the association between malignant lymphoma risk and the polymorphisms of the IL-1 gene family [IL-1B -31 C/T, IL-1A -889 C/T, and IL-1RN 86-bp variable number of terminal repeat (VNTR)] and myeloperoxidase (MPO -463 G/A). DESIGN AND METHODS: The hospital-based case-control study was conducted in Japan. Genotypes were examined in a total of 372 lymphoma cases and 241 non-cancer control subjects. The relative risks were estimated by unconditional logistic regression analysis. RESULTS: The overall allele distribution of these polymorphisms did not differ substantially between patients and controls; the odds ratios were 0.73 (95% confidence interval, 0.48-1.11) for the T allele carriers of IL-1B relative to the non-carriers, 1.01 (0.56-1.82) for the 2-repeat allele (allele 2) carriers of IL-1RN, 0.96 (0.62-1.48) for the T allele carriers of IL-1A, and 1.04 (0.70-1.57) for the A allele carriers of MPO. Subgroup analyses according to histology [diffuse large B-cell lymphoma (DLBL), follicular lymphoma, low-grade lymphoma of mucosa associated lymphoid tissue, and others] failed to illustrate differences except for DLBL which showed a possible association with IL-1A and IL-1B polymorphisms. INTERPRETATION AND CONCLUSIONS: Our data show a limited association between these polymorphisms and malignant lymphoma risk in total. The possible association of the IL-1A and IL-1B polymorphisms with DLB-needs further clarification.

Adolescent↗

PubMed2001

[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.

Adult↗

PubMed2001

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.

Adult↗

PubMed2000

Thermal transitions in the bilayer assembly of dimyristoylphosphatidylglycerol sodium salt dispersion in water: a new phase transition through an intermediate state.

The thermal properties of the dispersion of sodium salt of dimyristoylphosphatidylglycerol (NaDMPG) in water have been investigated as functions of incubation temperature and aging time by DSC, XRD, sodium ion activity, pH, zeta-potential, and IR measurements. The DSC charts for NaDMPG dispersions incubated below 30 degrees C showed an endothermic peak at 31.7 degrees C with a small shoulder peak at Tm (gel-liquid crystal transition temperature: 23.5 degrees C). The temperature of 31.7 degrees C coincides with the T* temperature at which a high-order transition in the NaDMPG bilayer assembly has been found to occur in our previous studies. However, no peak was observed for the dispersions incubated above 32 degrees C. These results indicate that thermal properties of NaDMPG bilayers definitely differ below and above the T* temperature. The dispersion which had been once incubated at 40 degrees C for 24 h never showed the endothermic peak at T* even after the further aging at 3 degrees C for 12-day. Namely, the NaDMPG bilayer assembly exhibits an intensive thermohysteresis. The XRD charts for the NaDMPG dispersions incubated at 25 degrees C showed a sharp X-ray diffraction pattern corresponding to the repeat distance of d = 4.75 nm regardless of their aging time, while the dispersions incubated at 40 degrees C had no diffraction peak until 9-day elapsed. After 10-day aging at 40 degrees C, however, a diffraction peak corresponding to d = 5.55 nm clearly appeared. In the DSC measurements for the dispersion incubated at 40 degrees C, a few endothermic peaks began to appear between Tm and T* after approximately 7-day aging. Then, they shifted toward higher temperatures and finally converged into a single peak at 40-42 degrees C after 14-day aging. These XRD and DSC peaks observed after a long period of aging time above T* suggest that conformations of the hydrophilic groups and the hydrocarbon chains in the NaDMPG bilayers take a more tight and closer arrangement very slowly via an intermediate state above T*, and a new gel phase of the bilayers is consequently formed, the transition temperature (T(I) temperature) of which is 40-42 degrees C. A molecular interpretation for such transition processes in the bilayer assembly of NaDMPG dispersions has been proposed on the basis of pH, sodium ion activity, zeta-potential, IR data, etc.

Calorimetry, Differential Scanning↗

PubMed2000

Severity of chronic atrophic gastritis and subsequent gastric cancer occurrence: a 10-year prospective cohort study in Japan.

Chronic atrophic gastritis is regarded as a predisposing factor for gastric cancer associated with Helicobacter pylori infection, and its severity is suggested to be a key influence on gastric cancer risk. Our purpose was to elucidate chronological change in cumulative risk of gastric cancer occurrence with various degrees of chronic atrophic gastritis by long-term follow-up. A total of 5373 subjects without cancer or resected stomachs who underwent gastroscopic examination and completed a life-style questionnaire between 1985-1989 were prospectively followed until December 1999. Relative risks of gastric cancer associated with baseline endoscopic findings were estimated using hazard ratios and their 95% confidence intervals with the Cox proportional hazard model, adjusting for gender, age and gastric cancer family history. After an average of 10 years of follow-up, 117 gastric cancer cases were identified. The risk was greatest among the subjects with moderate atrophy at baseline (hazard ratio: 2.22) and 4-6 years of follow-up (hazard ratio: 4.6-5.0). After this time point, risk attenuation with the length of follow-up period was observed. Our study gives the supportive evidence to the hypothesis that incomplete chronic atrophic gastritis and the processes occurring in atrophy are associated with development of gastric cancer.

Cohort Studies↗