Heme is a prosthetic group of various types of proteins, such as hemoglobin, myoglobin, cytochrome c, cytochrome p450, catalase and peroxidase. In addition, heme is involved in a variety of biological events by modulating the function or the state of hemoproteins. For example, protein synthesis is inhibited in erythroid cells under heme deficiency, as the consequence of the activation of heme-regulated inhibitor (HRI). Iron concentration in the cell is sensed and regulated by the heme-mediated oxidization and subsequent degradation of iron regulatory protein 2 (IRP2). Heme also binds to certain types of potassium channels, thereby inhibiting transmembrane K+ currents. Importantly, heme determines its own fate; namely, heme regulates its synthesis and degradation through the feedback mechanisms, by which intracellular heme level is precisely maintained. Heme reduces heme synthesis by suppressing the expression of non-specific 5-aminolevulinate synthase (ALAS1) and stimulates heme breakdown by inducing heme oxygenase (HO)-1 expression. ALAS1 and HO-1 are the rate limiting enzymes in heme biosynthesis and catabolism, respectively. Accordingly, under the heme-rich condition, heme binds to cysteine-proline (CP) motifs of ALAS1 and those of transcriptional repressor Bach1, thereby leading to repression of mitochondrial transport of ALAS1 and induction of HO-1 transcription, respectively. Moreover, chemosensing functions of HO-2 containing CP motifs, another isozyme of HO, have been unveiled recently. In this review article, we summarize and update the pleiotropic effects of heme on various biological events and the regulatory network of heme biosynthesis and catabolism.
New anticancer agents against lung cancer are needed because efficacy of chemotherapy is limited. The long time required, low quality, and considerable costs of registration-directed clinical trials in Japan (“Chiken”) have been pointed out. The quality of 24 phase I and 41 phase II trials of an anticancer drug for lung cancer were analyzed according to the approval year of the drug. The human resources and infrastructure to support oncology clinical practice and clinical trials were compared between Japan and the USA. A maximum tolerated dose was not defined in any of seven phase I trials before 1989, and was determined in two of six trials between 1989 and 1996 and in seven of 10 trials thereafter. Before 1989, 29 (20%) of 142 patients registered in two trials were ineligible, and the number of ineligible patients was not reported in the five trials. Sample size calculations were not performed in any of seven phase II trials before 1989 and were performed in only four of 10 trials between 1989 and 1996 and in all 23 trials conducted thereafter. The shortage of human resources, including medical oncologists, oncology nurse practitioners and clinical research coordinators, is serious and acute. The infrastructure to support clinical trials also remains insufficient in Japan. In conclusion, registration-directed clinical trials of anticancer agents have advanced significantly during last three decades but remain unsatisfactory. The development of infrastructure and human resources is an urgent task to ensure high-quality clinical trials without unnecessary delays.
Type 2 diabetes mellitus (DM) is a common and serious condition related with considerable morbidity. Screening for DM is one strategy for reducing this burden. In Japan National Diabetes Screening Program (JNDSP) guideline, the combined use of fasting plasma glucose (FPG) and glycated hemoglobin A1c (HbA1c) in a stepwise fashion has been recommended to identify the group of people needing life-style counseling or medical care. However, the efficacy of this program has not been fully evaluated, as an oral glucose tolerance test (OGTT) is not mandatory in the guideline. The aim of this study was to assess the validity of the screening test scenario, in which an OGTT would be applied to people needing life-style counseling or medical care on this guideline: FPG 110-125 mg/dl and HbA1c over 5.5%. Subjects were 1,726 inhabitants without a previous history of DM in the Funagata study, which is a population-based survey conducted in Yamagata prefecture to clarify the risk factors, related conditions, and consequences of DM. DM was diagnosed according to the 1999 World Health Organization criteria. The prevalence of undiagnosed DM was 6.6%. The tested screening scenario gave a sensitivity of 55.3%, a specificity of 98.4%, a positive predictive value of 70.8%, and a negative predictive value of 96.9% for undiagnosed DM. In conclusion, the screening test scenario, in which an OGTT would be followed by the combined use of FPG and HbA1c in a stepwise fashion according to the JNDSP guideline, was not effective in identifying people with undiagnosed DM.
Angiopoietins are endothelial growth factors, which play crucial roles in normal vascular development and tumor angiogenesis. We examined the expression profiles of angiopoietin-1 (Ang-1), angiopoietin-2 (Ang-2), vascular endothelial growth factor (VEGF), and Tie-2, a receptor for Ang-1 and Ang-2, in both colorectal adenocarcinoma and adjacent normal tissues, as judged by histology, in order to elucidate their relationships with microvascular density (MVD) and clinicopathologic properties. Higher MVD was associated with a lower degree of differentiation of colorectal adenocarcinoma. Immunohistochemical analysis revealed that the expression of Ang-2 and VEGF was significantly increased in colorectal adenocarcinoma compared to adjacent normal tissues (p < 0.01), and the expression of Ang-2 positively correlated with that of VEGF (r = 0.997, p < 0.01). In contrast, the expression of Ang-1 was lower in adenocarcinoma tissues than in adjacent normal tissues (p < 0.01), while there was no significant difference in Tie-2 expression in both tissues. Moreover, MVD was increased in Ang-2- and VEGF-expressing adenocarcinoma tissues compared to the Ang-2- and VEGF-negative tissues, respectively (p < 0.01). Importantly, MVD was lower in Ang-1-expressing adenocarcinoma tissues relative to Ang-1-negative tissues (p < 0.01). Furthermore, expression of Ang-2 as well as VEGF was significantly up-regulated in colorectal adenocarcinoma with diameters ≥ 5 cm or with lymph-node metastases (p < 0.01). In conclusion, the increased expression of Ang-2 and the decreased expression of Ang-1 may be responsible for blood vessel formation and rapid growth of the colorectal adenocarcinoma.
The proto-oncogene Ets-1 is a transcription factor that is known to regulate certain matrix metalloproteinases and plasminogen activator, which have been associated with malignant behaviors in solid carcinomas. We hypothesized that Ets-1 expression is also associated with tumor progression and a worse prognosis in lung carcinoma patients. To clarify the role of the Ets-1 proto-oncogene, the expression of Ets-1 in non-small cell lung carcinomas using 156 paraffin-embedded specimens was determined in surgically resected tissue samples. Immunohistochemical staining showed Ets-1 expression in 82 cases of 156 carcinomas (53%): 36 of 52 (69%) squamous cell carcinomas, 41 of 96 (43%) adenocarcinomas, and 5 of 8 (63%) other carcinomas. In adenocarcinomas, a higher proportion of acinar type expressed Ets-1 compared to papillary or alveolar type (p < 0.05). The proportion of adenocarcinoma that expressed Ets-1 increased with poorer histologic differentiation of the adenocarcinoma (p < 0.05). Ets-1 positive adenocarcinomas had a larger mean size than Ets-1 negative adenocarcinomas (p < 0.01). In adenocarcinoma patients, expression of Ets-1 was associated with disease-free (p = 0.09) and overall survivals (p < 0.05) after lung resection. Such relationship was not observed among squamous cell carcinoma patients. Our findings indicate that Ets-1 expression is related to histopathological differentiation, morphogenesis, and tumor progression of lung adenocarcinomas. Ets-1 appears to be a useful predictor of poor prognosis after surgical resection in lung adenocarcinoma patients. Ets-1 expression could be used to evaluate the malignant behaviors of lung adenocarcinomas.
Measurement of subcutaneous fat thickness with a skinfold caliper is a simple and inexpensive technique for assessment of body composition, but is influenced by the skin site or the obesity level. The resulting measurement errors may influence the prediction accuracy of body density. We therefore aimed to clarify the characteristics of measurement errors with a skinfold caliper and to determine useful measurement sites for the prediction of body density in Japanese adults of wide-ranging age and obesity levels. The present study included 126 Japanese male and 77 female subjects ranging from 21 to 81 years old. They were divided into a “non-obese group” and an “obese group”, based on the Japanese criteria of obesity (BMI ≥ 25 kg/m2). Subcutaneous fat thickness was measured at 14 sites with a skinfold caliper and ultrasound. Percent body fat was measured by dual-energy x-ray absorptiometry, and body density was calculated using Brozek's formula. Sex and obesity level differences in the measurement error of skinfolds (ultrasound minus skinfold caliper measurements) were examined by 2 × 2 ANOVA (sex and obesity groups) for each site. The relationship between body density and the systematic error was examined. We developed an accurate prediction equation for body density with smaller measurement and systematic errors. Although measurement errors in skinfold thickness tended to increase with increasing obesity levels, the influence was smaller for the abdominal and suprailiac skinfolds compared with other sites. Measurement of suprailiac or abdominal skinfold thickness is useful to accurately estimate body density in Japanese adults.
All types of cardiac surgery involve considerable injury to the myocardium. However, it is difficult to differentiate, in the immediate post-operative state, between ischemic alterations associated with the cardiac surgery itself and the pathological alterations of a peri-operative myocardial infarction. The diagnosis of damaged myocardium, classically performed with the enzymatic markers creatine kinase (CK) and its muscle fraction (CK-MB), has become more precise with the option of measuring cardiac troponins T and I. We measured these markers in 58 patients undergoing elective cardiac surgery with extra-corporeal circulation (ECC). The patients included 37 cases undergoing valve surgery, 14 for coronary revascularization, 6 for mixed procedures, and 1 for closure of an inter-atrial communication. The markers were measured in plasma at baseline (at anesthesia initiation), 5 min post-ECC commencement, following aorta de-clamping, during the surgical closure, and 6, 18 and 42 hrs after surgery. All the markers were increased significantly relative to the baseline values. Troponin I, CK and CK-MB values peaked between 6 and 18 hrs after surgery, troponin T between 18 and 42 hrs, and myoglobin at the surgical closure. The values of all markers were higher in patients undergoing coronary surgery compared to those in patients undergoing valve surgery. In the evaluation of myocardial damage after surgery, the measurement of classical markers such as CK and myoglobin remain valid, but other markers such as troponins provide significant additional diagnostic benefit and, thus, need to be included in the routine biochemical measurements for monitoring myocardial damage associated with the surgical procedure.
Adiponectin functions as an anti-inflammatory and anti-atherogenic factor, and the decreased plasma adiponectin is a risk factor for coronary disease. The aim of this study was to determine the changes in plasma levels of adiponectin, a potential parameter for atherosclerosis, in patients underwent surgical revascularization. We included forty patients with atherosclerosis (age, 58 ± 9 years; body mass index [BMI] 26.93 ± 2.3 kg/m2) undergoing coronary artery bypass grafting (CABG). Control group consisted of 40 healthy volunteers, matched for age, gender and BMI (age, 56 ± 6 years; BMI, 26.78 ± 2.3 kg/m2). We measured various parameters, including high sensitive C-reactive protein (hsCRP), homeostasis model assessment-insulin resistance (HOMA-IR) indexes, and adiponectin. The baseline profile of the patients before CABG showed higher levels of serum hsCRP (13.15 ± 2.40 mg/l vs 3.97 ± 1.07 mg/l) and HOMA-IR (1.86 ± 0.30 vs 1.26 ± 0.33) and lower plasma adiponectin levels (7.02 ± 2.01 μg/ml vs 25.46 ± 3.9 μg/ml), compared to controls (p < 0.001 for each parameter). Plasma adiponectin level was increased one month after CABG from the baseline level to 8.67 ± 2.05 μg/ml (p < 0.001), although the level was still lower than the control value. Thus, postoperative adiponectin level might be helpful for evaluating the progression of atherosclerosis. Moreover, CABG significantly decreased hsCRP to 7.25 ± 1.89 mg/l and HOMA-IR to 1.59 ± 0.33, although these levels were higher than the controls. These results suggest that CABG decreases the cardiac risk factors in atherosclerotic patients.
The changes in antioxidant-oxidant balance play important roles in the pathopysiology of neuropsychiatric conditions. Bipolar disorder (BD) is a psychiatric condition with recurrent mood disturbances. This study evaluates the effects of treatment with lithium, alone or in combination with antipsychotic olanzapine, on oxidant-antioxidant status and atherogenic character in patients with BD. The blood samples from 15 patients were tested before the treatment (pre-treatment phase) and at the ends of two consecutive treatment periods: period I, treatment with lithium and an antipsychotic drug, olanzapine (first 6 months) and period II, treatment with only lithium (6 months following period I). We measured serum atherogenic lipids (total cholesterol, triglycerides, and LDL-cholesterol), plasma lipid peroxides (thiobarbituric acid-reactive substances), antioxidant enzymes (glutathione peroxidase, superoxide dismutase, and catalase) in neutrophils and lymphocytes, and total antioxidant status in plasma. Compared with pre-treatment phase, the lipid parameters were increased with each treatment; especially, LDL-cholesterol was significantly increased only with lithium treatment. These findings alert to be cautious about use of lithium in patients with atherogenic conditions. Moreover, plasma lipid peroxides were decreased significantly after the combination therapy and further decreased with lithium treatment. Antioxidant enzyme activities in lymphocytes were decreased after both types of treatment. Importantly, plasma total antioxidant status was increased only with lithium treatment. Thus, treatment with lithium alone decreases already up-set oxidant status in BD. In conclusion, the combination therapy with olanzapine is better in terms of atherogenic profile, while lithium alone produces better antioxidant status in patients with BD.
Urocortin, a member of corticotropin releasing factor (CRF) peptide family, has positive chronotrophic and inotropic effects on heart and also shows a vasodilatory effect. However, the mechanism underlying its vasodilatory effect has yet to be elucidated. Endothelium-dependent relaxation of resistance arteries is mainly achieved by activation of K+ channels. Therefore, we investigated possible role of K+ channels and hyperpolarization for the vasodilatory effect of urocortin using the isolated perfused rat mesenteric arteries. Urocortin (0.2 nM) produced a slow-onset decrease in the perfusion pressure of the mesenteric vascular bed, which was elevated by an α1-adrenoceptor agonist, phenylephrine (2-4 μM). Urocortin also hyperpolarized the main mesenteric artery. Removal of endothelium with saponin treatment considerably inhibited the relaxation and hyperpolarization induced by urocortin. In contrast, the hyperpolarization was not significantly changed by cyclooxygenase inhibitor, indomethacin (1 μM) and/or nitric oxide synthase inhibitor, Nω-nitro-L-arginine (100 μM). Urocortin-induced relaxation was not affected by the combination of a guanylyl cyclase inhibitor, 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ, 1 μM), indomethacin and Nω-nitro-L-arginine. However, the relaxation and hyperpolarization were abolished by high extracelluler potassium concentration (40 mM) or by a large conductance Ca2+-activated K+ channel blocker, charybdotoxin (1 nM). Glibenclamide (1 μM), an ATP-dependent K+ channel inhibitor, did not affect the relaxation and hyperpolarization. These results suggest that urocortin causes endothelium-dependent relaxation and hyperpolarization of rat mesenteric arteries, probably through the activation of charybdotoxin sensitive Ca2+-activated K+ channels. These findings also indicate an essential role of the endothelium for the urocortin-elicited vascular relaxation and hyperpolarization.
Retropharyngeal abscess commonly develops among infants and small children, and is associated with the severe inflammation of the retropharyngeal lymph nodes located in the retropharyngeal space. Retropharyngeal abscess causes cervical pain, swelling, contracture of the neck, and in rare cases inflammatory torticollis, all of which result from an inflammatory process that irritates the cervical muscles, nerves or vertebrae. Here we report a rare case of retropharyngeal abscess with a complication of torticollis. A 4-year-old girl suffered from severe retropharyngeal abscess spreading through the deep cervical fascia, as judged by magnetic resonance imaging of the neck. Blood analysis showed high degree of inflammatory reactions, and so the patient was transferred to our hospital ward. The inflammation caused spasms of the prevertebral muscles, eventually leading to torticollis. The surgical drainage was performed immediately under general anesthesia, and an anti-inflammation therapy with intravenously administered meropenem trihydrate and clindamycin was used together with traction therapy to relieve the symptoms of the patient. We must be careful about the existence of epidural abscess and infectious spondylitis when the retropharyngeal abscess causes torticollis. In conclusion, an anti-inflammation therapy using antibiotics, along with traction therapy, was effective to relieve the symptoms. In addition to repeated clinical examinations, cooperation with orthopedists and careful follow-up are necessary. We also discussed the relationship between acute torticollis and retropharyngeal abscess.