Kinase activation through dimerization by human SH2-B

The isoforms of SH2-B, APS, and Lnk form a family of signaling proteins that have been described as activators, mediators, or inhibitors of cytokine and growth factor signaling. We now show that the three alternatively spliced isoforms of human SH2-B readily homodimerize in yeast two-hybrid and cellular transfections assays, and this is mediated specifically by a unique domain in its amino terminus. Consistent with previous reports, we further show that the SH2 domains of SH2-B and APS bind JAK2 at Tyr813. These findings suggested a model in which two molecules of SH2-B or APS homodimerize with their SH2 domains bound to two JAK2 molecules, creating heterotetrameric JAK2-(SH2-B)2-JAK2 or JAK2-(APS)2-JAK2 complexes. We further show that APS and SH2-B isoforms heterodimerize. At lower levels of SH2-B or APS expression, dimerization approximates two JAK2 molecules to induce transactivation. At higher relative concentrations of SH2-B or APS, kinase activation is blocked. SH2-B or APS homodimerization and SH2-B/APS heterodimerization thus provide direct mechanisms for activating and inhibiting JAK2 and other kinases from the inside of the cell and for potentiating or attenuating cytokine and growth factor receptor signaling when ligands are present.

Visualization of glucocorticoid receptor in the brain of green fluorescent protein–glucocorticoid receptor knockin mice

Glucocorticoids exert various neuroendocrinological effects, including stress response, in the central nervous system via glucocorticoid receptor (GR). GRs are transported from the cytoplasm to the nucleus upon ligand binding, and then exert the transcriptional activity. Although it is important for unraveling the actual property of the GR in vivo, subcellular dynamics of the GR are still unclear within the brain tissue in which the neuronal circuitry is maintained. To address this issue, we generated green fluorescent protein (GFP)-GR knockin mice, whose GR has been replaced by a GFP-GR fusion protein that is functionally indistinguishable from endogenous GR. In fixed brain sections of the GFP-GR knockin mice, the distribution of the green fluorescence was similar to that of GR immunoreactivity. By subtracting autofluorescence using fluorescent emission fingerprinting method with confocal laser scanning microscope, nuclear localization of GFP-GR was identifiable in the hippocampal CA3 subregion, where subcellular localization of the GR has been unsolved compared with other areas. To examine the subcellular trafficking of GFP-GR in vivo, we performed adrenalectomy on the GFP-GR knockin mice. GFP-GR was translocated from the nucleus to the cytoplasm and neurites two days after adrenalectomy. Furthermore, laser scanning cytometry by which fluorescence intensity in situ can be quantitatively measured revealed the entire GFP-GR expression level was increased. We then examined the dynamic changes in the subcellular localization of GFP-GR in living hippocampal neurons both in dissociated culture and in tissue slices. GFP-GR was localized in not only the perikarya but also neurites in the absence of ligand, and nuclear translocation following ligand treatment was observed. This is the first report visualizing subcellular trafficking of the GR in the mouse brain in more physiological condition. The present results propose new avenues for the research of the GR dynamics both in vitro and in vivo.

IL-10 is not required to prevent immune hyperactivity during memory responses to Toxoplasma gondii

Primary infection of IL-10 knockout (KO) mice with the protozoan parasite Toxoplasma gondii leads to a CD4(+)-T-cell dependent shock-like reaction with high systemic levels of IL-12 and IFN-gamma, severe liver pathology and death of mice. In the present study, this immune-mediated pathology was prevented by treatment of IL-10 KO mice with the anti-parasitic drug sulfadiazine, allowing these mice to progress to the chronic phase of infection. To address the role of endogenous IL-10 in the regulation of secondary immune responses to T. gondii, IL-10 KO mice were infected with the avirulent Me49 strain of this parasite, treated with sulfadiazine for 2 weeks starting at day 3 p.i., and were rechallenged 6 weeks p.i. with RH, a highly virulent strain of T. gondii. In these studies, chronically infected IL-10 KO mice survived secondary infection with RH and controlled parasite load. Although serum levels of IL-12 and IFN-gamma were higher in IL-10 KO mice than in wild type (WT) mice 8 days after RH rechallenge, these levels were well controlled in the absence of endogenous IL-10, suggesting that IL-10 is not required to down-regulate cytokine production during the memory response. Antigen-specific ex vivo recall responses further revealed that splenocytes from chronically infected WT and IL-10 KO mice responded to parasite antigen with similar production of IL-12 and IFN-gamma, and there was also no significant difference in ex vivo production of these cytokines by splenocytes in response to parasite antigen 7 days after secondary infection with T. gondii. Furthermore, IL-10 KO mice immunized with the Ts-4 vaccine-strain of T. gondii were protected when rechallenged with the virulent RH strain. Together, these studies demonstrate that the inhibitory effect of IL-10, which is required to prevent immune-mediated pathology during primary infection, is not required to prevent immune hyperactivity during a secondary response to T. gondii, and a highly effective memory response is generated in the absence of endogenous IL-10.

Rice bran extract prevents the elevation of plasma peroxylipid in KKAy diabetic mice

Oxidative stress is now considered to be a key factor in the development of diabetes and its complications. In this study, we examined the anti-oxidative effects of a crude lipophilic rice bran extract, Ricetrienol, which contains alpha-tocopherol, tocotrienol and phytosterol, in obese diabetic KKAy mice. We used KKAy mice fed a normal diet (DM group) or a diet including 0.1% Ricetrienol (RT group), and non-diabetic C57BL mice (C group). After 6 weeks, body weight, HbA1c, plasma glucose, lipids, peroxylipid (malonedialdehyde, MDA), alpha-tocopherol and glutathione peroxidase 1 (GPx) mRNA expression in the kidney were measured. At 1 week and at the end of the experimental period, urine 8-isoprostane and 8-hydroxy deoxyguanosine (8-OHdG) were also measured. Ricetrienol administration did not affect hyperglycemia, body weight or hyperlipidemia. Plasma MDA, urine 8-isoprostane and 8-OHdG in the DM group were significantly increased compared with the C group and the elevation of plasma MDA was significantly suppressed by 0.1% Ricetrienol. GPx mRNA expression was significantly increased in the RT group when compared with the C group. Plasma alpha-tocopherol in the RT group was significantly higher than that in the DM group. These findings suggest that Ricetrienol exerts a protective effect against oxidative damage in diabetes mellitus.

Prevalence and risk factors of erectile dysfunction in Japanese men with type 2 diabetes

This study aimed to elucidate the prevalence and clinical risk factors of erectile dysfunction (ED) in Japanese male diabetics. Questionnaires were administered to 82 male diabetics and 25 male non-diabetics (controls), to determine the international index of erectile function (IIEF). This index consists of five parts, with questions related to erectile function (EF), intercourse satisfaction (IS), orgasmic function (OF), sexual desire (SD), and overall satisfaction (OS). IIEF scores were compared between diabetics and controls, and were also analyzed in relation to clinical factors. Although EF, IS, and OF scores (physical factors) in diabetic men were significantly lower than those of age-matched controls, no significant differences were apparent in SD and OS scores (psychological factors). All patients with EF score > or = 18 reported being able to achieve sexual intercourse, we determined the criterion for ED as EF < 18. The prevalence of ED in diabetics and age-matched controls was 60% and 20%, respectively. EF score decreased with duration of diabetes and progression of retinopathy, proteinuria, ischemic heart disease, delayed nerve conduction, orthostatic intolerance, and attenuated heart rate variability. ED was found to be common in Japanese male diabetics. Possible influences of both microangiopathy and macroangiopathy on ED are suggested.

Effective doses of vecuronium in a patient with myotonic dystrophy*

Of the forms of muscular dystrophy, myotonic dystrophy has the greatest systemic involvement. Although most patients with myotonic dystrophy show normal sensitivity to non-depolarising neuromuscular blocking drugs, some have been reported to show greatly increased sensitivity to these drugs, and little is known about the sensitivity of different muscles. We compared effective doses of vecuronium in a patient with myotonic dystrophy at the orbicularis oculi, adductor pollicis and flexor hallucis brevis muscles during total intravenous anaesthesia. The calculated ED50 for the orbicularis oculi (7.77 microg x kg(-1) (95% CI 3.10-16.8 microg x kg(-1))) was lower than for the adductor pollicis (25.3 microg x kg(-1) (95% CI 20.7-43.3 microg x kg(-1))) and flexor hallucis brevis muscles (29.5 microg x kg(-1) (95% CI 11.0-85.6 microg x kg(-1); p < 0.01)). The ED90 was also lower for the orbicularis oculi (35.7 microg x kg(-1) (95% CI 14.8-66.5 microg x kg(-1))) than for the other muscles (51.8 microg x kg(-1) (95% CI 29.3-145.0 microg x kg(-1)) and 50.6 microg x kg(-1) (95% CI 5.29-642.0 microg x kg(-1)), respectively) (p < 0.01)).

History of obesity as a risk factor for both carotid atherosclerosis and microangiopathy

As a westernized lifestyle becomes widespread in Japan, the number of individuals with obesity, as well as type 2 diabetes, is rapidly increasing. In this investigation, we studied the prevalence of obesity and its association with the development of diabetic macroangiopathy and microangiopathy. The clinical records of 634 patients in our hospital with type 2 diabetes were surveyed. The relationship between obesity and diabetic retinopathy and nephropathy and macroangiopathy (carotid artery intima-media thickness, IMT) was examined using univariate and multivariate analysis. A body mass index (BMI) > or = 25 kg/m2 was used as the diagnostic criterion for obesity. The prevalence of obesity at the time of the survey was 35% and a history of obesity was reported in 70% of the survey population. Multiple regression analysis revealed that the maximum BMI was significantly correlated with IMT thickening. The prevalence of nephropathy in previously obese patients was significantly higher than in non-obese patients. The maximum BMI was significantly associated with the development of retinopathy and nephropathy, as shown by logistic regression analysis. This suggests that a history of obesity may be an important risk factor for the development of micro- and macroangiopathy in Japanese with type 2 diabetes.

A phenylalanine zipper mediates APS dimerization

The APS, SH2-B and LNK proteins are adapters that activate and modulate receptor tyrosine kinase and JAK/STAT signaling. We now show that a conserved N-terminal domain mediates APS homodimerization. We determined the crystal structure of the dimerization domain at a resolution of 1.7 A using bromide ion MAD phasing. Each molecule contributes two helices to a compact four-helix bundle having a bisecting-U topology. Its most conspicuous feature is a stack of interdigitated phenylalanine side chains at the domain core. These residues create a new motif we refer to as a 'phenylalanine zipper,' which is critical to dimerization. A newly developed bridging yeast tri-hybrid assay showed that APS dimerizes JAK2, insulin receptor and IGF1 receptor kinases using its SH2 and dimerization domains. Dimerization via the phenylalanine zipper domain provides a mechanism for activating and modulating tyrosine kinase activity even in the absence of extracellular ligands.

Functional variants in the glutathione peroxidase-1 (GPx-1) gene are associated with increased intima-media thickness of carotid arteries and risk of macrovascular diseases in japanese type 2 diabetic patients

Atherosclerosis in type 2 diabetic patients has been linked to increased oxidative stress. Glutathione peroxidase-1 (GPx-1) plays an important role in the antioxidant defense of the vascular wall. To assess the association between variants in the GPx-1 gene and atherosclerosis, we screened the gene in 184 Japanese type 2 diabetic patients and identified four polymorphisms (-602A/G, +2C/T, Ala(5)/Ala(6), and Pro198Leu). Among these polymorphisms, -602G, +2T, Ala(6), and 198Leu were in strong linkage disequilibrium with each other. The patients were divided into two groups on the basis of the codon 198 polymorphism, Pro/Pro (n = 151) and Pro/Leu (n = 33), to analyze clinical characteristics. The mean intima-media thickness (IMT) of common carotid arteries (P = 0.0028) and the prevalence of cardiovascular disease (P = 0.035) and peripheral vascular disease (P = 0.027) were significantly higher in the Pro/Leu group than in the Pro/Pro group. In vitro functional analyses indicated that the combination of polymorphisms (Ala(6)/198Leu) of the GPx-1 gene had a 40% decrease in enzyme activity, and the combination of polymorphisms (-602G/+2T) had a 25% decrease in transcriptional activity. These results suggest that functional variants in the GPx-1 gene are associated with increased IMT of carotid arteries and risk of cardiovascular and peripheral vascular diseases in type 2 diabetic patients.

Neurosarcoidosis with spinal root pain as the first symptom

We report a 60-year-old woman with neurosarcoidosis. She was referred to our hospital for examination of the cause of pain in left Th4-6 dermatome. Chest X-ray and computed tomography (CT) revealed bilateral hilar and mediastinal lymphadenopathy, and her serum angiotensin converting enzyme (ACE) level was elevated. Histological finding of mediastinal lymph nodes consisted with sarcoidosis. Therefore, her pain was thought to be spinal root pain caused by neurosarcoidosis. With the administration of prednisolone, her symptom and bilateral hilar lymphadenopathy disappeared, and serum ACE level became normal. It is important to pay attention to neurosarcoidosis when patients show unknown spinal root symptom, although it is rare.

Epidemiology of malignant neoplasms in soft tissue during childhood

Employing the data of the Hokkaido Children's Cancer Registry, incidences of malignant neoplasms in soft tissue during childhood were estimated. During 25 years (1975--1999), a total of 110 such cases (0-14 years of age) were registered. The average incidence was 0.40 per 100,000 population aged 0-14 years. The incidence of rhabdomyosarcoma (RMS) was 0.24, accounting for 60% of all malignant neoplasms in soft tissue. 30% of the malignant neoplasms in soft tissue were found in the head/face/neck. The share of RMS in the upper limbs was 76%, while that in the chest was 25%. Mortality due to malignant neoplasms in soft tissue was estimated using the data of vital statistics of all Japan. The average mortality of all malignant neoplasms in soft tissue was about 0.15 per 100,000 population aged 0-14 years, which was almost constant throughout the 25 years. Both the mortality at 5-9 years of age and that at age 10-14 years increased, while that at 0-4 years had a tendency to decrease. The prolongation of the survival period in the 0-4-year age group due to the progress in therapy may have brought about a shift of the age at death to older age groups, leading to a decrease in the mortality at 0-4 years of age.

Effects of neuromuscular-blocking drugs in rats in vivo: direct measurements in the diaphragm and tibialis anterior muscle

BACKGROUND

Effects of neuromuscular-blocking drugs are often investigated in rodents using both the diaphragm in vitro and the tibialis anterior muscle in vivo. Differences in the properties of these muscles cannot be neglected. We evaluated the neuromuscular effects of drugs on the rat diaphragm in vivo in comparison with the tibialis anterior muscle, directly measuring twitch tension with a force transducer.

METHODS

Respectively using sternotomy and an approach via the gluteal space, transducers were attached to the diaphragm and the tibialis anterior muscle. Phrenic and sciatic nerves were stimulated supramaximally by single square pulses to record isometric contraction of muscles. Pancuronium, vecuronium, or rocuronium was infused continuously at a rate adjusted repeatedly until stable tension was obtained. Effective doses for 50% (ED 50) and 90% (ED 90) depression of tension were calculated, using a cumulative infusion dosing method.

RESULTS

Isometric contraction of the diaphragm could be recorded despite movements of the heart and lungs. For all three drugs, both mean ED 50 and ED 90 were more than twice as large for the diaphragm as for the tibialis anterior (P<0.05). In addition, slopes of dose-response curves for the diaphragm were significantly less steep than those of the tibialis anterior for the three drugs.

CONCLUSION

Neuromuscular-blocking effects on the diaphragm can be recorded in vivo. According to direct contractile force measurement, the diaphragm is more resistant to non-depolarizing neuromuscular-blocking drugs than the tibialis anterior muscle.

Ocular surface epithelium induces expression of human mucosal lymphocyte antigen (HML-1) on peripheral blood lymphocytes

BACKGROUND/AIMS

Peripheral blood CD8+ lymphocytes that home to mucosal surfaces express the human mucosal lymphocyte antigen (HML-1). At mucosal surfaces, including the ocular surface, only intraepithelial CD8+ lymphocytes express HML-1. These lymphocytes are retained in the intraepithelial compartment by virtue of the interaction between HML-1 and its natural ligand, E-cadherin, which is expressed on epithelial cells. The purpose of this study was to determine whether ocular surface epithelial cells (ocular mucosa) could induce the expression of human mucosal lymphocyte antigen on peripheral blood lymphocytes.

METHODS

Human corneal and conjunctival epithelial cells were co-cultured with peripheral blood lymphocytes. Both non-activated and activated lymphocytes were used in the experiments. After 7 days of incubation, lymphocytes were recovered and analysed for the antigens CD8/HML-1, CD4/HML-1, CD3/CD8, CD3/CD4, CD3/CD25, CD8/CD25, and CD4/CD25 by flowcytometry.

RESULTS

Significant statistical differences were observed in the CD8/HML-1 expression when conjunctival epithelial cells were co-cultured with non-activated and activated lymphocytes (p = 0.04 for each) and when corneal epithelial cells were co-cultured with non-activated lymphocytes (p = 0.03). Significant statistical difference in CD4/HML-1 expression was observed only when conjunctival epithelial cells were co-cultured with activated lymphocytes (p = 0.02).

CONCLUSION

Ocular surface epithelial cells can induce the expression of human mucosal lymphocyte antigen on CD8+ (and to some extent on CD4+) lymphocytes. This may allow the retention of CD8+ and CD4+ lymphocytes within the epithelial compartment of the conjunctiva and play a part in mucosal homing of lymphocytes.

Uncoupling protein 2 promoter polymorphism -866G/A affects its expression in beta-cells and modulates clinical profiles of Japanese type 2 diabetic patients

Common uncoupling protein 2 (UCP2) promoter polymorphism -866G/A is reported to be associated with its expression in adipose tissue and the risk of obesity in Caucasians. On the other hand, several studies suggested that UCP2 expression in beta-cells is an important determinant of insulin secretion. In the Japanese population, morbid obesity is very rare, and insulin secretion capacity is relatively low as compared with Caucasians. Because UCP2 would link to insulin secretion and obesity, it might explain this ethnic difference. Here, we report that the UCP2 promoter with the A allele showed higher promoter activity in the INS-1 beta-cell line. The frequency of the A allele is higher in our Japanese study than that in Caucasians. Type 2 diabetic patients with the A allele need insulin therapy earlier and showed higher frequency of insulin treatment. Moreover glucose-induced early insulin secretion is significantly lower in patients with the A allele. However, there was no difference in allele frequency between obese and lean type 2 diabetic patients. In conclusion, UCP2 promoter polymorphism -866G/A does not affect obesity in Japanese type 2 diabetic patients but affects its transcription in beta-cells and modulates glucose-induced insulin secretion and eventually insulin requirement in Japanese type 2 diabetic patients. Higher A allele frequency in the Japanese population might partly explain the ethnic difference of insulin secretion capacity.

Is the mass screening for neuroblastoma ineffective?

Though a recent study (Schilling et al. 2002) concluded that the mass screening for neuroblastoma targeting children age 12 months was ineffective, we pointed out several serious problems and reestimated its effectiveness using their data. They employed the subjects in the "control area" as controls, not the "non-participants" whose biases are fewer because their area is the same as that of the participants. The incidence of neuroblastoma among the subjects in the "control area" was about 25% smaller than that of the "non-participants". This leads to underestimation of the effectiveness of the mass screening. They combined false negatives with true positives to calculate the incidence of the "screened group". But since many spontaneous regression cases are included in the true positives, this method inflates the incidence of the "screened group", leading to underestimation of the effectiveness of the mass screening. When the false negatives are compared with the non-participants, the incidence of the cases in stage 4 among the latter is about 40% of that of the former, and the mortality is less than two-thirds. The percentage of spontaneous regression cases among the true positives is estimated to be about 40%. These results are better than those of the Japanese screening programs (targeting infants age 6 months), supporting the effectiveness of mass screening for neuroblastoma.

A rare case of autoimmune polyglandular syndrome type 3

A 57-year-old female was admitted to our hospital suffering from a lower lip tumor, small ulcers in the arms and alopecia of the head. Because she had type 2 diabetes mellitus (DM) for the past 3 years, she was referred to our department of internal medicine for its treatment. Her endogenous insulin secretion was much decreased despite the short duration of diabetes. Glutamic acid decarboxylase antibodies (GADA) and islet cell antibodies (ICA) were both positive. Therefore, she was diagnosed as having slowly progressive form of type 1 DM. Type 1 DM is sometimes complicated with autoimmune disorders. After further examinations, she was diagnosed as having Sjögren's syndrome, Graves' disease and autoimmune neutropenia (AIN). According to the histological examinations of the lip tumor and peripheral site of the skin ulcer, the patient was diagnosed as having carcinoma spinocellulare and chronic cutaneous lupus erythematosus. The examination also showed positive anti-intrinsic factor and anti-ribonucleoprotein (RNP) antibodies. She is a rare case of an autoimmune polyglandullar syndrome (APS) type 3 simultaneously manifesting these seven diseases with multiple autoimmune antibodies.

Dedifferentiation and decreased expression of adhesion molecules, E-cadherin and ZO-1, in colorectal cancer are closely related to liver metastasis

Carcinoma cells with high metastatic potential often show a dedifferentiated phenotype at the primary site. In this study, a total of 48 cases (24 primary tumors of colorectal cancer (Pr-CRC) with liver metastasis, 24 without) were examined for E-cadherin and ZO-1 expression by immunohistochemical staining, and for their dedifferentiated phenotype. The expression levels of E-cadherin and ZO-1 were markedly decreased in the cancer cells of tumors with liver metastasis. Moreover, dedifferentiation of cancer cells, which was evaluated by the modified Gleason score, was also related to liver metastasis. However, none of the conventional clinicopathologic parameters of invasion, except lymph node metastasis, showed any relationship with liver metastasis. These results indicate that dedifferentiation and a decreased expression of E-cadherin and ZO-1 are closely related to liver metastasis.

Dynamic shear properties of the temporomandibular joint disc

Shear stress might be an important factor associated with fatigue failure and damage of the temporomandibular joint disc. Little information, however, is available on the dynamic behavior of the disc in shear. Since the disc is an anisotropic and viscoelastic structure, in the present study the dependency of the dynamic shear behavior on the direction and frequency of loading was examined. Ten porcine discs were used for dynamic shear tests. Shear stress was applied in both anteroposterior (A-P test) and mediolateral (M-L test) directions. The dynamic moduli increased as the loading frequency increased. The dynamic elasticity was significantly larger in the A-P test than in the M-L test, although the dynamic viscosity was similar in both tests. The present results suggest that non-linearities, compression/shear coupling, and intrinsic viscoelasticity affect the shear material behavior of the disc, which might have important implications for the transmission of load in the temporomandibular joint.

Nonsense and missense mutations in the human hepatocyte nuclear factor-1 beta gene (TCF2) and their relation to type 2 diabetes in Japanese

Mutations in transcription factors expressed in the pancreatic beta-cell are a major cause of maturity-onset diabetes of the young (MODY). They have also been found in patients diagnosed with type 1 and type 2 diabetes mellitus, which may highlight the difficulty in diagnosing these forms of diabetes or perhaps indicate a direct role in the development of multiple forms of diabetes. We have screened the hepatocyte nuclear factor-1 beta (HNF-1 beta/MODY5) gene for mutations in a group of 126 unrelated Japanese patients with type 2 diabetes and a family history of at least one first degree relative with diabetes. We identified one patient with a nonsense mutation (R276X) and another with a missense mutation (S465R). These mutations were present in the heterozygous state and were not found in 132 nondiabetic subjects (264 normal alleles). We identified a second patient with the S465R mutation on screening a second group of 272 randomly selected type 2 diabetic patients but not in another 122 nondiabetic subjects. Functional studies indicated that R276X-HNF-1 beta was inactive and S465R-HNF-1 beta exhibited a 22% reduction in activity compared with the wild-type protein. The S465R mutation may function in a dominant-negative manner. The subject with the R276X mutation had MODY5 misdiagnosed as common type 2 diabetes. He was diagnosed with diabetes at 13 yr of age and also had small kidneys with multiple bilateral renal cysts and decreased urinary concentrating ability. The two subjects with the S465R mutation had typical late-onset type 2 diabetes and no evidence of kidney disease. We have identified two novel mutations in human HNF-1 beta gene. The prevalence of MODY5 among our population of Japanese diabetes patients with a strong positive family of disease is 0.8%. The S465R mutation was found in 0.5% of our patients with common type 2 diabetes and thus may be a rare genetic risk factor contributing to the development of type 2 diabetes rather than MODY5.

Sequence analysis of the pro-opiomelanocortin (POMC) gene in obese/diabetic Japanese

Pro-opiomelanocortin (POMC)-derived peptides play a critical role in body weight regulation in the central nervous system. Mice deficient in POMC developed obesity. We sought mutations in the POMC gene in 50 morbidly obese (body mass index 35-60 kg/m(2)) Japanese subjects with diabetes by direct sequencing. Apart from two silent mutations (C6982T and C7285T), no other mutations were detected. Frequencies of these mutations were not significantly different between 100 obese subjects and 100 controls. Also, the frequencies did not differ in the subjects with or without diabetes. These results suggest that mutations in the POMC gene are unlikely to be a major factor of obesity or diabetes in Japanese subjects.

Steroid effects on secretion from subsets of lactotrophs: role of folliculo-stellate cells and annexin 1

Prolactin secretion is controlled by the hypothalamus, and by circulating steroids; oestrogens stimulate, but glucocorticoids inhibit prolactin release. Lactotrophs express intracellular receptors for oestrogens, but apparently not glucocorticoids. Therefore, a genomic effect of oestrogens could be direct, but that of glucocorticoids appears to be indirect. Lactotrophs are not a homogeneous cell population: some have large irregular dense-cored vesicles, others have small round vesicles, but the functional significance of this inhomogeneity is far from clear. Oestradiol and testosterone can stimulate rapid release of prolactin selectively from type II lactotrophs characterised by small round vesicles. Progesterone and other steroids do not exert this effect, which results from a non-genomic action of oestradiol and testosterone. Glucocorticoid inhibition of secretagogue-induced prolactin secretion is mimicked by annexin 1 (lipocortin 1), a protein induced by glucocorticoids in the pituitary and many other tissues, and can be blocked by annexin 1 immunoneutralisation and antisense. Glucocorticoid inhibition of ACTH and growth hormone secretion also involves annexin 1. Pituitary annexin 1 is located in folliculo-stellate cells; these express glucocorticoid receptors, and glucocorticoids induce annexin-1 synthesis. Annexin 1 is externalised from folliculo-stellate cells in response to glucocorticoids, despite the fact that it lacks a secretory signal sequence and is not packaged in vesicles. Inhibition of annexin 1 externalisation by glyburide suggests involvement of an ABC (ATP-binding cassette) transporter in externalisation. Both oestradiol and glucocorticoids therefore influence the secretion of prolactin by novel direct and indirect mechanisms, in addition to their much better understood effects on transcription via classical intracellular steroid receptors.

Contribution of HPLC mass screening for neuroblastoma to a decrease in mortality

The aim of this study is the estimation of the contribution of HPLC mass screening for neuroblastoma to the decrease in deaths due to this disease. The mortality rates of malignant neoplasms of the adrenal glands (ICD 9, 1940; ICD 10, C74; virtually all the cases of these codes are neuroblastoma during childhood) at 1-4 years of age in cohorts born in 1979-1984, 1985-1988, and 1989-1992 in the whole of Japan were calculated, using data obtained from the Ministry of Health and Welfare. The numbers of infants screened by HPLC in the cohorts were estimated through the reports of the Ministry of Health and Welfare and the database of the Japanese Society for Mass-screening. The mortality of the cohort born in 1989-1992, in which 77.8% of the live births were screened by HPLC, was 1.73 per 100,000 live births. This is about half of that (3.26) of the cohort born in 1979-1984, in which few infants were screened. On the assumption that cases of the 1985-1988 and 1989-1992 cohorts died according to the mortality rate of the 1979-1984 cohort, the expected numbers of deaths were estimated; that for the 1985-1988 cohort was 178.51 (of them, that for the infants screened by HPLC was 39.65), and that for the 1989-1992 cohort was 159.78 (of them, that for the infants screened by HPLC was 124.33). The observed numbers of deaths were 145 and 85, respectively. Assuming that non-HPLC methods have no effects and using 2 unknown quantities x (contribution of HPLC) and y (other factors), simultaneous equations (1) 178.51 - 39.65x - 178.51y = 145 and (2) 159.78 - 124.33x - 159.78y = 85 were made. Solving them, x = 0.5041 and y = 0.0757 were obtained. In conclusion HPLC screening targeting infants aged 6 months reduces death of adrenal neuroblastomas at 1-4 years of age by about 50%.

Store-operated Ca2+ entry uncoupled with ryanodine receptor and junctional membrane complex in heart muscle cells

Store-operated Ca2+ entry (SOCE) is the Ca2+ influx that is activated on depletion of intracellular Ca2+ stores. Although SOCE is found in a variety of cell types, its activation mechanism and molecular identity remain to be clarified. Current experimental results suggest that SOCE channels are activated by direct coupling with Ca2+ release channels on depleted stores. Here we report SOCE in cardiac myocytes, that was prominently sensitive to Zn2+ but resistant to inhibitors for voltage-dependent Ca2+ channels and Na+/Ca2+ exchangers. The SOCE activity may be developmentally regulated, because the SOCE was easily detected during embryonic and neonatal stages but not in mature myocytes from adult hearts. In cardiac myocytes, ryanodine receptor type 2 (RyR-2) is thought to be the sole Ca2+ release channel on the intracellular store, and junctophilin type 2 (JP-2) contributes to formation of the junctional complex between the cell surface and store membranes. Using the knockout mice, we also examined possible involvement of the Ca2+ release channel and junctional membrane complex in cardiac SOCE. Apparently normal SOCE activities were retained in mutant myocytes lacking RyR-2 or JP-2, suggesting that neither the Ca2+ release channel nor junctional membrane complex is involved in activation of cardiac SOCE.

Motoneuron-specific expression of NR3B, a novel NMDA-type glutamate receptor subunit that works in a dominant-negative manner

We have identified a novel glutamate receptor subunit on the human and mouse genome. Cloning of the mouse cDNA revealed a protein consisting of 1003 amino acids encoded by at least nine exons. This protein showed the highest similarity (51%) to the NR3A subunit of the NMDA receptor and therefore was termed NR3B. NR3B has a structure typical of glutamate receptor family members with a signal peptide and four membrane-associated regions. Amino acids forming a ligand-binding pocket are conserved. When coexpressed with NR1 and NR2A in heterologous cells, NR3B suppressed glutamate-induced current similarly to NR3A. Thus members of the NR3 class of NMDA receptors act as dominant-negative subunits in the NMDA receptor complex. NR3B shows very restricted expression in somatic motoneurons of the brainstem and spinal cord. Its expression in other types of motoneurons, including autonomic motoneurons in Onuf's nucleus and oculomotor neurons, is significantly weaker. Our results indicate that NR3B is important as a regulatory subunit that controls NMDA receptor transmission in motoneurons. It may be involved in the pathogenesis of neurodegenerative diseases involving motoneurons as well.

Abnormal formation of sarcoplasmic reticulum networks and triads during early development of skeletal muscle cells in mitsugumin29-deficient mice

Recently, we detected a novel membrane protein, mitsugumin29 (MG29), in the triads in rabbit skeletal muscle cells and suggested important roles for this membrane protein in the formation of the sarcoplasmic reticulum (SR) networks and triads in muscle cells. In the present study, we examined the development of skeletal muscle cells in MG29-deficient mice to try to determine the roles played by MG29 in the formation of the SR networks and triads. Ultrastructural observations revealed some morphological abnormalities in these mice, such as incomplete formation of the SR networks, an irregular running of the transverse tubule and a partial defect in the triads at the A-I junctional region. These ultrastructural abnormalities occurred during early myogenesis and were preserved until the adult stage. The possible roles for MG29 in the formation of SR networks and triads in skeletal muscle cells are discussed in the light of these observations.

Ultrashort-laser-pulse-induced persistent spectral hole burning of Eu(3+) in sodium borate glasses

We have observed persistent spectral hole burning (PSHB) in Eu(3+) -doped sodium borate glasses irradiated with near-IR femtosecond laser pulses. As-prepared glasses, i.e., glasses melted in air, do not show PSHB even at low temperatures (~77K) , but room-temperature PSHB occurs in the irradiated glasses. The exposure to IR radiation causes both the reduction of Eu(3+) to Eu(2+) and the formation of intrinsic defects. We propose that the photoinduced redistribution of electric charges between Eu(3+) to Eu(2+) is responsible for the occurrence of PSHB.

Association of plasma free-3-methoxy-4-hydroxyphenyl (ethylene)glycol, natural killer cell activity and delirium in postoperative patients

We measured and compared levels of plasma free 3-methoxy-4-hydroxyphenyl (ethylene)glycol (pMHPG), a major metabolite of noradrenaline, and natural killer (NK) cell activity in 26 patients prior to their undergoing an operation for cardiovascular diseases; 11 of whom expressed delirium and 15 who did not. In conclusion, we found that pMHPG levels before an operation were higher in patients with postoperative delirium than in the patients without, while NK cell activity showed no difference between the two groups. It is possible that hyperactivity of noradrenargic neurons is connected with the development of postoperative delirium. Furthermore, we considered that measurement of pMHPG level before operation might be a useful tool to predict the occurrence of postoperative delirium.

Partially disordered antiferromagnetic phase in Ca(3)CoRhO(6)

Neutron diffraction experiments are reported on Ca(3)CoRhO(6) which consists of ferromagnetic Ising spin chains on a triangular lattice. It was first confirmed from temperature dependence of the (110) peak intensity that Ca(3)CoRhO(6) realizes a partially disordered antiferromagnetic state, where 2/3 of the ferromagnetic chains order antiferromagnetically with each other and the remaining 1/3 are left incoherent with the other chains. The 1/3 incoherent ferromagnetic Ising chains freeze to maintain a disordered state at lower temperatures. This compound is successfully discussed as a candidate of a nonequilibrium one-dimensional Ising model.

Dzyaloshinski-Moriya interaction in the 2D spin gap system SrCu(2)(BO(3))(2)

The Dzyaloshinski-Moriya interaction partially lifts the magnetic frustration of the spin-1/2 oxide SrCu(2)(BO(3))(2). It explains the fine structure of the excited triplet state and its unusual magnetic field dependence, as observed in previous ESR and new neutron inelastic scattering experiments. We claim that it is mainly responsible for the dispersion. We propose also a new mechanism for the observed ESR transitions forbidden by standard selection rules, which relies on an instantaneous Dzyaloshinski-Moriya interaction induced by spin-phonon couplings.

Postural tachycardia syndrome in a 28-year-old Japanese woman

Postural tachycardia syndrome is defined as the development of orthostatic symptoms without orthostatic hypotension. We report a 28-year-old female patient with postural tachycardia syndrome who exhibited palpitation, low-grade fever and weight loss. Evaluation of autonomic nervous system functions showed that cardiovagal function was normal. Sweat response to acetylcholine was decreased. Excessive blood pressure elevation was seen in phase IV of the Valsalva maneuver. Pathophysiologic factors in this case were considered to be alpha adrenergic denervation and beta adrenergic hyperresponsiveness. It is important that this syndrome be widely recognized and properly diagnosed.

Serotonergic neurones in the dorsal raphe nucleus that project into the medial preoptic area contain oestrogen receptor beta

Serotonin is involved in female sexual behaviour in which the medial preoptic area (MPA) has a pivotal role. The present study used immunohistochemistry, in situ hybridization and retrograde transport analysis to investigate whether serotonin neurones in the dorsal raphe nucleus (DRN) of females projecting into the MPA contained oestrogen receptor alpha or beta. The projection of serotonin neurones from the DRN to the MPA was confirmed using the microinjection of Fluoro-Gold (FG), a fluorescent retrograde tracer, into the MPA of ovariectomized (OVX-group) and OVX-rats treated with oestradiol benzoate (E2-group). A number of serotonin neurones in the DRN were labelled with FG, indicating that these serotonin neurones in DRN project their terminals into the MPA. FG-labelled serotonin neurones expressed ERbeta mRNA in the DRN, and the number of the serotonin neurones containing ERbeta mRNA between the OVX-group and the E2-treated group was not significantly different. Serotonin neurones in the DRN did not express ERalpha-immunoreactivity. Since previous findings showed that the density of serotonin-immunoreactive fibres and the concentration of serotonin within the MPA was significantly lower in the E2-group than the OVX-group, our present observations suggested that the regulatory effects of E2 on the serotonergic neurone system in the MPA may be via ERbeta within the serotonin-containing cells in the DRN of female rats.

A suspected case of proximal diabetic neuropathy predominantly presenting with scapulohumeral muscle weakness and deep aching pain

A 48-year-old man with a 14-year history of type 2 diabetes with proliferative diabetic retinopathy and distal symmetrical diabetic polyneuropathy visited our hospital. Eight months later, he subacutely developed difficulty in both shoulder movement and trouble standing up from a squatting position. This was accompanied by severe bilateral shoulder and thigh pain. Magnetic resonance imaging of the brain, cervical and lumbar spine, computed tomography of the shoulder and X-ray films of the cervical spine and shoulder revealed no abnormality. Cerebrospinal fluid showed a mild elevation of protein (0.93 g/l) without cell infiltration. Antiganglioside antibodies and point mutation of mitochondrial DNA at position 3243 were not found. Neuropathology of the sural nerve showed a moderate myelinated fiber loss, active axonal degeneration, but onion-bulb formation, endoneurial or epineurial vasculitis were not observed. Electromyography revealed neurogenic changes in the proximal upper limb muscles. Nerve conduction studies revealed mild bilateral slowing in nerve conduction velocity in both of the upper and lower limbs. The diagnosis of this patients was suspected to be a proximal diabetic neuropathy (diabetic amyotrophy). The pain and muscle weakness had persisted more severely in the shoulder than in the thigh throughout the clinical course. His unbearable symptoms could be partially alleviated by an administration of a selective serotonin reuptake inhibitor, fluvoxamine maleate. Proximal diabetic neuropathy is a rare disabling type of neuropathy, which is characterized with subacute bilateral muscle weakness and wasting in the proximal part of the lower limbs. The involvement of the scapulohumeral region observed in this case is very unusual in proximal diabetic neuropathy.

Clinicopathologic and prognostic significance of matrilysin expression at the invasive front in human colorectal cancers

Matrix metalloproteinases (MMPs) have been implicated in tumor progression. Matrilysin, one of the matrix metalloproteinases, is frequently overexpressed in gastrointestinal cancers. The aim of our study was to assess the validity of matrilysin as a prognostic marker of colorectal cancers. Matrilysin expression was immunohistochemically analyzed using formalin-fixed, paraffin-embedded specimens from 113 colorectal cancer patients who had undergone curative surgery. The lumenal surface of neoplastic glands in the superficial layer was apically stained, while the cytoplasm of cancer cells at the invasive front was diffusely stained for matrilysin. Sections with immunostaining signals in more than 30% of carcinoma cells at the invasive front, which were observed in 47 (42%) cases, were judged as being positive for matrilysin. Matrilysin positivity was significantly correlated with the depth of invasion, lymph node metastasis, lymphatic invasion, advanced Dukes' stage and poor outcome. Patients with matrilysin-positive cancer had a significantly shorter overall survival time than those with matrilysin-negative cancer. For patients with intermediate invasive tumor (T2 or T3), only matrilysin was a significant prognostic variable for predicting overall survival in multivariate analysis. Matrilysin expression at the invasive front could be an important marker, predicting an unfavorable prognosis after surgical treatment in patients with colorectal cancer.

Clinicopathologic and prognostic significance of matrilysin expression at the invasive front in human colorectal cancers

Matrix metalloproteinases (MMPs) have been implicated in tumor progression. Matrilysin, one of the matrix metalloproteinases, is frequently overexpressed in gastrointestinal cancers. The aim of our study was to assess the validity of matrilysin as a prognostic marker of colorectal cancers. Matrilysin expression was immunohistochemically analyzed using formalin-fixed, paraffin-embedded specimens from 113 colorectal cancer patients who had undergone curative surgery. The lumenal surface of neoplastic glands in the superficial layer was apically stained, while the cytoplasm of cancer cells at the invasive front was diffusely stained for matrilysin. Sections with immunostaining signals in more than 30% of carcinoma cells at the invasive front, which were observed in 47 (42%) cases, were judged as being positive for matrilysin. Matrilysin positivity was significantly correlated with the depth of invasion, lymph node metastasis, lymphatic invasion, advanced Dukes' stage and poor outcome. Patients with matrilysin-positive cancer had a significantly shorter overall survival time than those with matrilysin-negative cancer. For patients with intermediate invasive tumor (T2 or T3), only matrilysin was a significant prognostic variable for predicting overall survival in multivariate analysis. Matrilysin expression at the invasive front could be an important marker, predicting an unfavorable prognosis after surgical treatment in patients with colorectal cancer.

Deficiency of triad junction and contraction in mutant skeletal muscle lacking junctophilin type 1

In skeletal muscle excitation-contraction (E-C) coupling, the depolarization signal is converted from the intracellular Ca2+ store into Ca2+ release by functional coupling between the cell surface voltage sensor and the Ca2+ release channel on the sarcoplasmic reticulum (SR). The signal conversion occurs in the junctional membrane complex known as the triad junction, where the invaginated plasma membrane called the transverse-tubule (T-tubule) is pinched from both sides by SR membranes. Previous studies have suggested that junctophilins (JPs) contribute to the formation of the junctional membrane complexes by spanning the intracellular store membrane and interacting with the plasma membrane (PM) in excitable cells. Of the three JP subtypes, both type 1 (JP-1) and type 2 (JP-2) are abundantly expressed in skeletal muscle. To examine the physiological role of JP-1 in skeletal muscle, we generated mutant mice lacking JP-1. The JP-1 knockout mice showed no milk suckling and died shortly after birth. Ultrastructural analysis demonstrated that triad junctions were reduced in number, and that the SR was often structurally abnormal in the skeletal muscles of the mutant mice. The mutant muscle developed less contractile force (evoked by low-frequency electrical stimuli) and showed abnormal sensitivities to extracellular Ca2+. Our results indicate that JP-1 contributes to the construction of triad junctions and that it is essential for the efficiency of signal conversion during E-C coupling in skeletal muscle.

The renal metabolism of insulin: urinary insulin excretion in patients with mutant insulin syndrome (insulin Wakayama)

Many studies have shown that the kidney plays an important role in the metabolism of many proteins and small peptides. To understand insulin handling in the kidney, we examined urinary insulin excretion under several conditions in patients with mutant insulin syndrome (MIS; insulin Wakayama). Urinary excretion of insulin was studied using high-performance liquid chromatography analysis in patients with MIS. In these patients, most of the insulin extracted from a 24-hour urine collection and from urine collected after stimulation of insulin secretion by glucose or glucagon was normal insulin, whereas 90% of serum insulin is structurally abnormal (Leu-A3 insulin). On the other hand, arginine, which is known as an inhibitor of renal tubular reabsorption, increased urinary excretion of Leu-A3 insulin. The ratio of Leu-A3 and normal insulin in urine after arginine was similar to that in serum. A large amount of Leu-A3 insulin is excreted in urine when reabsorption of insulin at renal tubules is inhibited by arginine. These data indicate that normal and Leu-A3 insulin are filtered through the glomerulus with relatively little restriction. Using the fact that basal urine has a high concentration of normal insulin and an extremely low concentration of Leu-A3 insulin, which has less receptor-binding affinity, we speculated some possibilities. One possibility is that both forms of insulin are reabsorbed by the tubular cells, but with different efficiencies. Leu-A3 insulin absorption in more complete, and this suggests differences in the uptake pathways that may account for the differences in response to arginine infusions. Another possibility is that only normal insulin is secreted from tubules into urine which is mediated by receptors. Our results provide new insight into renal metabolism of insulin and showed that MIS is a useful model for studying it.

Structural determination of the subsidiary colors in food blue No. 1 (brilliant blue FCF) aluminum lake detected by paper chromatography

One of eight Food Blue No. 1 aluminum lakes (B-1Als) used in the official inspection of coal-tar colors in fiscal year 1999 had a violet sub-spot during paper chromatography and was rejected. To clarify the orgin of the sub-spot, the violet subsidiary color (Sub-V) was isolated from the sample. On the basis of NMR and MS analyses and ion chromatography, the structure of the subsidiary color was elucidated to be 2-[[4-[N-ethyl-N-(3- sulfophenylmethyl)amino]phenyl][4-hydroxyphenyl]methylio]benzenesulfonic acid. The relative content of Sub-V to that of m,m-B-1 in the rejected sample was determined to be 39.5% by HPLC. The relative contents in other submitted samples of B-1Al were in the range of 1.1-3.6%.

Intracellular dynamics of steroid hormone receptor

Steroid hormones substantially influence brain development, reproduction sexual differentiation and emotion. These effects are mediated by steroid hormone receptors and cofactors, which directly regulate gene expression. Deciphering how and where these transcriptional activators occur in a cell provides the groundwork for elucidating the influence of these small hydrophobic signal molecules on various brain functions. This paper describes some of the recent investigations into the subcellular localization of steroid hormone receptors and cofactors using GFPs and other immunocytochemical methods.

Determination of pyrimethamine in animal tissue and egg by liquid chromatography with fluorescence detection

A sensitive and selective liquid chromatographic (LC) assay was developed to determine the concentration of pyrimethamine in animal tissue and egg by fluorescent derivative. Animal samples were extracted with acetonitrile, centrifuged, and purified by hexane. Fluorescent derivatization was performed by reacting pyrimethamine with chloroacetaldehyde and subjected to LC with fluorescence detection (excitation wavelength 300 nm, emission wavelength 420 nm). The limit of detection was 10 ng/g (10 ppb) and the standard calibration curve was linear in the range of 1-100 ppb (0.01-1 ng/10 microL). Recoveries from samples fortified at levels of 0.1 and 1 ppm (microg/g) were 61.0-77.4 and 65.5-81.2%, respectively. The method was applied to the monitoring of marketed samples. Pyrimethamine was not determined in any of the 70 samples: 20 swine muscle; 20 chicken muscle; 10 chicken liver; and 20 egg.

Dynamic changes in subcellular localization of mineralocorticoid receptor in living cells: in comparison with glucocorticoid receptor using dual-color labeling with green fluorescent protein spectral variants

Mineralocorticoid receptor (MR) and glucocorticoid receptor (GR) are ligand-dependent transcription factors. Although it is generally accepted that GR is translocated into the nucleus from the cytoplasm only after ligand binding, the subcellular localization of MR is still quite controversial. We examined the intracellular trafficking of MR in living neurons and nonneural cells using a fusion protein of green fluorescent protein (GFP) and rat MR (GFP-MR). Corticosterone (CORT) induced a rapid nuclear accumulation of GFP-MR, whereas in the absence of ligand, GFP-MR was distributed in both cytoplasm and nucleus in the majority of transfected cells. Given the differential action of MR and GR in the central nervous system, it is important to elucidate how the trafficking of these receptors between cytoplasm and nucleus is regulated by ligand. To examine the simultaneous trafficking of MR and GR within single living cells, we use different spectral variants of GFP, yellow fluorescent protein (YFP) and cyan fluorescent protein (CFP), linked to MR and GR, respectively. In COS-1 cells, expressing no endogenous corticosteroid receptors, the YFP-MR chimera was accumulated in the nucleus faster than the CFP-GR chimera in the presence of 10(-9) M CORT, while there was no significant difference in the nuclear accumulation rates in the presence of 10(-6) M CORT. On the other hand, in primary cultured hippocampal neurons expressing endogenous receptors, the nuclear accumulation rates of the YFP-MR chimera and CFP-GR chimera were nearly the same in the presence of both concentrations of CORT. These results suggest that CORT-induced nuclear translocation of MR and GR exhibits differential patterns depending on ligand concentrations or cell types.

Antimicrobial alkaloids from Zanthoxylum tetraspermum and caudatum

Two benzophenanthrene alkaloids, 8-acetonyldihydronitidine and 8-acetonyldihydroavicine were isolated from Zanthoxylum tetraspermum stem bark along with liriodenine, sesamin, lichexanthone and (+)-piperitol-gamma,gamma-dimethylallylether. The species endemic to Sri Lanka, Z. caudatum, contained sesamin, savinin, liriodenine, decarine and 8-O-desmethyl-N-nornitidine. 8-Acetonyldihydronitidine and 8-acetonyldihydroavicine showed significant antibacterial activity while the former along with liriodenine was strongly antifungal. Savinin exhibited potent spermicidal activity. Both savinin and sesamin exhibited significant insecticidal activity.

A polymorphic marker in the leptin gene associated with Japanese morbid obesity

The prevaleance of morbid obesity (body mass index of 35.0 or greater) is low in Japan (0.2-0.3%), and little systematic investigation of its cause in this population has been carried out. Leptin plays a central role in regulation of body weight; mice deficient in leptin develop marked obesity. We sought mutations in the leptin gene in 53 morbidly obese Japanese (maximum body mass index 35-60) including 46 with type 2 diabetes. Direct DNA sequencing was performed following polymerase chain reaction amplification. Apart from a silent mutation at codon 25 (CAA/CAG, glutamine) detected in eight subjects, no mutations were detected. We found a significantly higher prevalence of the variant leptin 25CAG allele among the 53 obese subjects (0.085) studied than in 132 nonobese control subjects (0.011, P<0.001). In Japanese populations mutations in the protein coding sequence of the leptin gene are unlikely to be a major cause of morbid obesity. However, the leptin 25CAG allele may be linked to morbid obesity in this population. Specifically, genetic variation located near the leptin gene may be involved in pathogenesis. The leptin polymorphism 25CAG appears to be a new genetic marker for obesity susceptibility, at least in Japanese.