The Tohoku Journal of Experimental Medicine
Online ISSN : 1349-3329
Print ISSN : 0040-8727
ISSN-L : 0040-8727
Volume 226 , Issue 1
January
Showing 1-12 articles out of 12 articles from the selected issue
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  • Hideaki Suzuki, Masanori Hirose, Satoshi Watanabe, Koji Fukuda, Shin F ...
    2012 Volume 226 Issue 1 Pages 3-10
    Published: 2012
    Released: November 30, 2011
    JOURNALS FREE ACCESS
    Although cardiac sensation, such as palpitation or chest pain, is common and is sometimes a malignant sign of heart diseases, the mechanism by which the human brain responds to afferent signals from the heart remains unclear. In this study, we investigated whether electrical stimulation of the heart provokes brain responses in humans. We examined 15 patients (age: 65.4 ± 3.1 years old, 11 males and 4 females) implanted with either a cardiac pacemaker or cardiac resynchronization therapy (CRT) device. Electroencephalogram (EEG) was simultaneously recorded from the vertex during right ventricular pacing at 70-100 beats/min at baseline (1.5 V) and intense (6-8 V) stimulation sessions. We evaluated brain responses to cardiac electrical stimulation by measuring cerebral potentials that were obtained by subtracting the average of 100 EEG waves triggered by cardiac pacing during baseline stimulation from those during the intense stimulation. Intense stimulation of the cardiac pacemaker or CRT device reproducibly induced cardiac sensation in 6 out of the 15 patients; namely, the remaining 9 patients showed no reproducible response. Brain responses were evident by averaging cerebral potentials from all of the 15 patients and those from 6 patients with reproducible cardiac sensation. To the best our knowledge, this is the first report that demonstrates the brain responses to cardiac electrical stimulation in humans. This new method should be useful for examining pathophysiology of cardiac diseases with pathological cardiac sensation, including cardiac anxiety and silent myocardial ischemia.
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  • Nan Zhang, Cao Yu, Denggui Wen, Jun Chen, Yiwei Ling, Kenshi Terajima, ...
    2012 Volume 226 Issue 1 Pages 11-17
    Published: 2012
    Released: December 07, 2011
    JOURNALS FREE ACCESS
    The incidence of esophageal squamous cell carcinoma (ESCC), which is the eighth most common malignancy worldwide, is highest in China. The purpose of this study was to investigate the association between nitrogen compounds in drinking water with the incidence of ESCC by geographical spatial analysis. The incidence of ESCC is high in Shexian county, China, and environmental factors, particularly nitrogen-contaminated drinking water, are the main suspected risk factors. This study focuses on three nitrogen compounds in drinking water, namely, nitrates, nitrites, and ammonia, all of which are derived mainly from domestic garbage and agricultural fertilizer. The study surveyed 48 villages in the Shexian area with a total population of 54,716 (661 adults with ESCC and 54,055 non-cancer subjects). Hot-spot analysis was used to identify spatial clusters with a high incidence of ESCC and a high concentration of nitrogen compounds. Logistic regression analysis was used to detect risk factors for ESCC incidence. Most areas with high concentrations of nitrate nitrogen in drinking water had a high incidence of ESCC. Correlation analysis revealed a significant positive relationship between nitrate concentration and ESCC (P = 0.01). Logistic regression analysis also confirmed that nitrate nitrogen has a significantly higher odds ratio. The results indicate that nitrate nitrogen is associated with ESCC incidence in Shexian county. In conclusion, high concentrations of nitrate nitrogen in drinking water may be a significant risk factor for the incidence of ESCC.
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  • Cai-Mei Zheng, Pauling Chu, Chia-Chao Wu, Wen-Ya Ma, Kuo-Chin Hung, Yu ...
    2012 Volume 226 Issue 1 Pages 19-27
    Published: 2012
    Released: December 10, 2011
    JOURNALS FREE ACCESS
    Secondary hyperparathyroidism (SHPT) is a common complication in chronic renal disease. Osteoprotegerin (OPG), an extracellular cytokine receptor secreted by osteoblasts, can promote bone formation by inhibiting the function of osteoclasts. Hemodialysis (HD) patients have elevated serum OPG levels. OPG secretion can be suppressed with high parathyroid hormone (PTH) levels. HD patients with refractory SHPT can benefit from parathyroidectomy (PTX) treatment, but the changes of serum OPG, bone turnover markers and bone mineral density (BMD) following PTX in HD patients remain unclear. In this study, patients on maintenance HD who received PTX for refractory SHPT (n = 28) were prospectively followed for 1 year. Serum intact PTH (iPTH), alkaline phosphatase (Alk-P), and OPG were measured serially; BMD was measured pre-PTX and at 1 year after PTX. After PTX, serum iPTH levels reduced profoundly. Serum Alk-P levels increased rapidly, peaking at 2 weeks post-PTX, while serum OPG levels gradually increased at 2 weeks after PTX and peaked at 2 months. BMD improved in both femoral neck (FN; cancellous and cortical bone) and lumbar spine (LS; cancellous bone). Higher baseline iPTH levels were associated with greater FN and LS BMD improvements at one year after PTX. The increment of serum OPG was correlated with the increase in LS BMD, implying that inhibition of osteoclastic bone resorption may improve BMD within the first year after PTX. These findings suggest that PTX removes the suppressive effects of high PTH on OPG secretion, resulting in the increased serum OPG levels that may contribute to BMD improvement.
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  • Xinxing Xie, Aijun Sun, Wenqing Zhu, Zheyong Huang, Xinying Hu, Jiangu ...
    2012 Volume 226 Issue 1 Pages 29-36
    Published: 2012
    Released: December 17, 2011
    JOURNALS FREE ACCESS
    Stem cell transplantation has become a promising therapeutic approach for the treatment of myocardial infarction (MI). However, the poor survival of the donor cells after transplantation has restricted its therapeutic efficacy. Hydrogen sulfide (H2S), one gaseous signaling molecule, has been applied to inhibit cell apoptosis and promote cell survival. In the present study, we therefore examined the effects of H2S on the survival of mesenchymal stem cells (MSCs). MSCs were isolated from the femur of male Sprague-Dawley rats (about 4 weeks old, 100 g). Preconditioning MSCs with 200 μmol/L NaHS (as the donor of H2S) for 30 min decreased the hypoxia-induced cell apoptosis in vitro. The mechanisms contributing to the beneficial effects of H2S on MSCs were associated with increased levels of phosphorylated Akt (pAkt), phosphorylated Erk1/2 (pErk1/2) and phosphorylated glycogen synthase kinase-3β (pGSK-3β) in MSCs. Subsequently, MSCs (1 × 106), MSCs preconditioned with H2S (1 × 106), or phosphate buffered saline (PBS) were injected into rat hearts immediately after MI (the ligation of the left anterior descending of coronary artery). Real-time PCR for the Sry gene, located on the Y chromosome, indicated that preconditioning with H2S improved the survival rate of the transplanted MSCs in infarcted myocardium 4 days after MI, compared with the untreated MSCs. Furthermore, transplantation of the H2S-pretreated MSCs reduced the infarct size and increased left ventricular (LV) function, as judged by transthoracic echocardiography. In conclusion, H2S preconditioning effectively promotes MSCs survival under ischemic injury and helps cardiac repair after MI, which has great clinical significance.
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  • Takuya Ito, Kiyoe Funamoto, Naoaki Sato, Ai Nakamura, Kaori Tanabe, Te ...
    2012 Volume 226 Issue 1 Pages 37-44
    Published: 2012
    Released: December 17, 2011
    JOURNALS FREE ACCESS
    Maternal undernutrition during pregnancy is a risk factor for cerebrovascular and cardiovascular diseases in adulthood. Hypoxia-inducible factor 1 alpha (HIF1α) plays an essential role in cellular hypoxic responses, and its increased expression is associated with cerebrovascular and cardiovascular diseases. However, it is not known whether maternal undernutrition influences HIF1α expression in the fetal brain. We therefore analyzed the expression levels of HIF1α and its downstream genes in the fetal brain (day 17.5 of gestation, 1-2 days before birth). Maternal undernutrition did not noticeably affect the fetal body and brain weights. Both HIF1α mRNA and protein levels were increased in the brain under maternal undernutrition, despite the absence of hypoxia, as judged by the staining profile with hypoxyprobe-1 that identifies hypoxic cells. Importantly, maternal undernutrition caused the accumulation of HIF1α protein in oligodendrocyte precursor cells at the subventricular zone, a site of neurogenesis in the fetal brain. Maternal undernutrition also increased the mRNA level of mammalian target of rapamycin (mTOR), which could increase the level of HIF1α protein under normoxia. Furthermore, microarray analysis revealed that expression levels of mRNAs for 10 HIF1α downstream targets, including enolase 1 and hexokinase 1, were increased in the fetal brain under maternal undernutrition. Thus, the biochemical consequence of maternal undernutrition is similar to that of mild hypoxia. In conclusion, maternal undernutrition induces the expression of HIF1α in oligodendrocyte precursor cells at the subventricular zone, and it also induces the expression of hypoxia-related genes in the fetal brain probably via activation of the mTOR pathway.
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  • Katsunori Iijima, Yasuhiko Abe, Tomoyuki Koike, Kaname Uno, Hiroyuki E ...
    2012 Volume 226 Issue 1 Pages 45-53
    Published: 2012
    Released: December 21, 2011
    JOURNALS FREE ACCESS
    Although Helicobacter pylori (H. pylori) eradication has some inhibitory effects on the subsequent development of gastric cancer, there are sporadic cases of gastric cancer even after successful eradication. The pathogenesis of gastric cancer emerging after H. pylori eradication remains to be clarified. In this study, employing Congo-red chromoendoscopy, which is capable of visualizing the acid-secreting fundic mucosa, we investigated the topographic relationship of the acid secretion pattern to the occurrence site of gastric cancers emerging after eradication. Fourteen consecutive patients who suffered from new gastric cancer after eradication, defined as lesions that were discovered at least 2 years after the eradication, were prospectively enrolled. Whether the neoplasias arose from acid-secreting or non-acid-secreting areas was evaluated with Congo-red chromoendoscopy. Biopsy specimens taken from the two areas were subjected to histologic evaluation and immunohistochemistry for Ki-67 and p53. The mean period from the eradication to the subsequent occurrence of gastric cancer was 74 (44) months. There were two cancer lesions in 5 cases, and thus there was a total 19 lesions from 14 cases. Congo-red chromoendoscopy revealed that all 19 lesions arose exclusively from non-acid-secreting areas. Histological examination revealed sustained hyperproliferation and accumulation of p53 protein was frequently detectable in non-acid-secreting areas. Genetic alteration such as p53 mutation seems to be already present in the residual non-acid-secreting areas after eradication, areas that could be the origin of gastric carcinogenesis after eradication. Identification of such high-risk areas should be a promising approach for estimating the individual cancer risk after eradication.
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  • Yuka Ekawa, Mitsuru Shiota, Takako Tobiume, Masao Shimaoka, Mitsuhiro ...
    2012 Volume 226 Issue 1 Pages 55-58
    Published: 2012
    Released: December 21, 2011
    JOURNALS FREE ACCESS
    Reversible posterior leukoencephalopathy syndrome (RPLS) is characterized by clinical symptoms such as seizures, visual disturbance, and altered mental status. It also presents abnormal findings on computed tomography (CT) and magnetic resonance imaging (MRI) indicating cerebral edema in the white matter of the occipital, temporal, and parietal lobes. Both the clinical symptoms and abnormal imaging findings can be reversed by controlling blood pressure or treating the underlying condition including infection. This report describes a patient with RPLS that occurred secondary to eclampsia. A 26-year-old female, gravida 0 para 0, developed weakness and pain in her upper and lower extremities and gait disturbance during the 34th week of pregnancy, and severe pregnancy-induced hypertension near the end of the 37th week. On the first day of the 38th week, she developed constricted visual fields and complained of visual illusions. MRI revealed a high-signal-intensity area in the right occipital lobe. Immediately after MRI, the patient had a 10-sec tonic convulsion. Diagnosed with eclampsia, she underwent emergency cesarean section. MRI on the 2nd postoperative day showed that the high-signal-intensity area was slightly improved. Her visual illusions were diminished by the 4th postoperative day, and almost all subjective symptoms disappeared by the 7th postoperative day. The patient was discharged at 12th postoperative day. We recommend MRI not only for symptomatic patients with suspected RPLS, but also for asymptomatic patients with severe pregnancy-induced hypertension. If findings such as cerebral edema are observed on MRI, immediate delivery should be considered before eclamptic seizures or exacerbation of neurological symptoms.
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  • Zhang Zhang, Tao Su, Liang He, Hongtao Wang, Gang Ji, Xiaonan Liu, Yun ...
    2012 Volume 226 Issue 1 Pages 59-68
    Published: 2012
    Released: December 22, 2011
    JOURNALS FREE ACCESS
    Natural killer (NK) cells play important roles in the immune defense against tumor cells. The function of NK cells is determined by a balance between activating and inhibitory signals. DNAX accessory molecule-1 (DNAM-1) and NK group 2 member D (NKG2D) are major NK cell activating receptors, which transduce activating signals after binding their ligands CD155, CD112 and major histocompatibility complex class I-related chains A and B (MICA/B). However, the expression and functions of these ligands in colon carcinoma are still elusive. Here, we show the higher expression of CD155, CD112 and MICA/B in colon carcinoma tissues, although no correlations between the ligands expression and patient clinicopathological parameters were found. The subsequent cytotoxicity assay indicated that NK cells effectively kill colon carcinoma cells. Functional blocking of these ligands and/or receptors with antibodies led to significant inhibition of NK cell cytotoxicity. Importantly, expression of DNAM-1 and NKG2D was reduced in NK cells of colon cancer patients, and this reduction could directly suppress the activation of NK cells. Moreover, colon cancer patients have higher serum concentrations of sCD155 and sMICA/B (soluble ligands, secreted or shed from cells) than those in healthy donors (sCD155, 127.82 ± 44.12 vs. 63.67 ± 22.30 ng/ml; sMICA, 331.51 ± 65.23 vs. 246.74 ± 20.76 pg/ml; and sMICB, 349.42 ± 81.69 vs. 52.61 ± 17.56 pg/ml). The up-regulation of these soluble ligands may down-regulate DNAM-1 and NKG2D on NK cells, ultimately leading to the inhibition of NK cytotoxicity. Colon cancer might be a promising target for NK cell-based adoptive immunotherapy.
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  • Sukru Aksoy, Nese Cam, Mehmet Rasit Guney, Ufuk Gurkan, Dilaver Oz, Es ...
    2012 Volume 226 Issue 1 Pages 69-73
    Published: 2012
    Released: December 27, 2011
    JOURNALS FREE ACCESS
    Patients with severe aortic regurgitation frequently present with angina pectoris. The exact pathophysiology for angina in aortic regurgitation is not clear. Left ventricular hypertrophy and myocardial blood supply-demand mismatch have been the suggested mechanisms to explain ischemia. However, no conclusive clinical study exists to define the incidence of ischemia in patients with severe aortic regurgitation and normal coronary arteries. We, therefore, investigated the frequency of myocardial ischemia in relation to left ventricular hypertrophy or dilatation in patients with severe aortic regurgitation and normal coronary arteries. We reviewed the medical records of all patients (n = 311) with aortic valve replacement due to aortic regurgitation between 2007 and 2010. We selected subjects with normal coronary arteries (n =182) for the study purpose, and we identified 35 patients who underwent myocardial perfusion scintigraphy prior to the coronary angiography (19 female and 16 male subjects; age 45.0 ± 8.9 years). Left ventricular hypertrophy and dilatation were detected in 9 (26%) and 5 (14%) patients, respectively. Myocardial perfusion scintigraphy showed evidence of ischemia in 10 (29%) patients with normal coronary arteries. The presence of ischemia did not relate to the presence of left ventricular hypertrophy and/or dilatation. As a potential mechanism, aortic regurgitation causes backflow of blood from the aorta into the left ventricle, hence disturbs coronary flow dynamics. In conclusion, myocardial ischemia is common (nearly one-third) among patients with severe aortic regurgitation even in the absence of coronary obstruction, left ventricular hypertrophy and/or dilatation.
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  • Yusuke Saito, Tetsuya Ono, Naoki Takeda, Takehiko Nohmi, Masayuki Seki ...
    2012 Volume 226 Issue 1 Pages 75-83
    Published: 2012
    Released: December 27, 2011
    JOURNALS FREE ACCESS
    Thymine DNA glycosylase (TDG) is involved in the repair of G:T and G:U mismatches caused by hydrolytic deamination of 5-methylcytosine and cytosine, respectively. Recent studies have shown that TDG not only has G-T/U glycosylase activities but also acts in the maintaining proper epigenetic status. In order to investigate the function of TDG in vivo, mice lacking Tdg, Tdg (−/−), were generated. Tdg mutant mice died in utero by 11.5 days post coitum (dpc), although there were no significant differences in the spontaneous mutant frequencies between wild type and Tdg (−/−) embryos. On the other hand, the levels of noradrenaline in 10.5 dpc whole embryos, which is necessary for normal embryogenesis, were dramatically reduced in Tdg (−/−) embryos. Consequently, we tested the effect of D, L-threo-3, 4-dihydroxyphenylserine (DOPS), a synthetic precursor of noradrenaline, on the survival of the Tdg (−/−) embryos. DOPS was given to pregnant Tdg (+/−) mice from 6.5 dpc through drinking water. Most of the Tdg (−/−) embryos were alive at 11.5 dpc, and they were partially rescued up to 14.5 dpc by the administration of DOPS. In contrast, the administration of L-3, 4-dihydroxyphenylalanine (L-DOPA) had marginal effects on Tdg (−/−) embryonic lethality. No embryo was alive without DOPS beyond 11.5 dpc, suggesting that the lethality in (−/−) embryos is partially due to the reduction of noradrenaline. These results suggest that embryonic lethality in Tdg (−/−) embryos is due, in part, to the reduction of noradrenaline levels.
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  • Hee Suk Park, Bo Youl Choi, Young Dae Kwon
    2012 Volume 226 Issue 1 Pages 85-93
    Published: 2012
    Released: December 28, 2011
    JOURNALS FREE ACCESS
    The number of symptomatic hepatitis A cases has progressively been increasing during the last several years in Korea. Available cost estimates indicate a growing burden to the public. The purpose of this study was to determine the extent of treatment costs for patients with hepatitis A and to analyze the influential factors with nationwide data. We collected data on 72,921 patients with hepatitis A from 5-year National Health Insurance claim archives between 2004 and 2008. Multiple regression analyses were conducted to examine influential factors affecting treatment costs for hepatitis A. Total treatment costs for patients with hepatitis A during the 5-year period were US$47,902,087 and increased significantly each year. In total, 91.4% of treatment costs were used for hospitalization, and the proportion of inpatients increased gradually throughout the study period. The most influential factor on treatment costs was treatment duration. Our results show that the soaring number of patients with hepatitis A followed by the hospitalization-focused treatment practice is a major factor associated with the rapid increase in treatment costs. Appropriate policies should be promptly developed to control treatment costs and economic burden of hepatitis A infections.
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