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Makoto Tominaga

Publications and source records attributed to Makoto Tominaga.

At least 19 recordsLinked to original sources
PubMed2006

TRPM2 activation by cyclic ADP-ribose at body temperature is involved in insulin secretion.

There are eight thermosensitive TRP (transient receptor potential) channels in mammals, and there might be other TRP channels sensitive to temperature stimuli. Here, we demonstrate that TRPM2 can be activated by exposure to warm temperatures (>35 degrees C) apparently via direct heat-evoked channel gating. beta-NAD(+)- or ADP-ribose-evoked TRPM2 activity is robustly potentiated at elevated temperatures. We also show that, even though cyclic ADP-ribose (cADPR) does not activate TRPM2 at 25 degrees C, co-application of heat and intracellular cADPR dramatically potentiates TRPM2 activity. Heat and cADPR evoke similar responses in rat insulinoma RIN-5F cells, which express TRPM2 endogenously. In pancreatic islets, TRPM2 is coexpressed with insulin, and mild heating of these cells evokes increases in both cytosolic Ca(2+) and insulin release, which is K(ATP) channel-independent and protein kinase A-mediated. Heat-evoked responses in both RIN-5F cells and pancreatic islets are significantly diminished by treatment with TRPM2-specific siRNA. These results identify TRPM2 as a potential molecular target for cADPR, and suggest that TRPM2 regulates Ca(2+) entry into pancreatic beta-cells at body temperature depending on the production of cADPR-related molecules, thereby regulating insulin secretion.

Animals↗
PubMed2006

Increased sensitivity of desensitized TRPV1 by PMA occurs through PKCepsilon-mediated phosphorylation at S800.

Important mechanisms that regulate inhibitory and facilitatory effects on TRPV1-mediated nociception are desensitization and phosphorylation, respectively. Using Ca2+-imaging, we have previously shown that desensitization of TRPV1 upon successive capsaicin applications was reversed by protein kinase C activation in dorsal root ganglion neurons and CHO cells. Here, using both Ca2+-imaging and patch-clamp methods, we show that PMA-induced activation of PKCepsilon is essential for increased sensitivity of desensitized TRPV1. TRPV1 has two putative substrates S502 and S800 for PKCepsilon-mediated phosphorylation. Patch-clamp analysis showed that contribution of single mutant S502A or S800A towards increased sensitivity of desensitized TRPV1 is indistinguishable from that observed in a double mutant S502A/S800A. Since S502 is a non-specific substrate for TRPV1 phosphorylation by kinases like PKC, PKA or CAMKII, evidence for a role of PKC specific substrate S800 was investigated. Evidence for in vivo phosphorylation of TRPV1 at S800 was demonstrated for the first time. We also show that the expression level of PKCepsilon paralleled the amount of phosphorylated TRPV1 protein using an antibody specific for phosphorylated TRPV1 at S800. Furthermore, the anti-phosphoTRPV1 antibody detected phosphorylation of TRPV1 in mouse and rat DRG neurons and may be useful for research regarding nociception in native tissues. This study, therefore, identifies PKCepsilon and S800 as important therapeutic targets that may help regulate inhibitory effects on TRPV1 and hence its desensitization.

Amino Acid Sequence↗
PubMed2006

Correlation between change in body weight rather than current body weight and change in serum adiponectin levels in a Japanese population -- the Funagata study.

Serum adiponectin levels are decreased in obese subjects. We examined the association of current body weight (BW) and its change with a change in serum adiponectin levels. Serum adiponectin levels at the baseline (from 1995 to 1997) and the 5-year follow-up (from 2000 to 2002) examinations were evaluated in 1003 (M/F, 425/578; age at the baseline examinations, 58.3 +/- 11.7/57.5 +/- 11.0 years) Japanese subjects from a cohort population (N = 2013) of the Funagata study. Correlations and associations of BW at the baseline examinations and changes in BW between the baseline and the follow-up examinations (deltaBW) with changes in the serum adiponectin levels in the study period (deltaAdiponectin) were examined. Stepwise regression analyses revealed a significant correlation of the deltaBW (r = -0.233 and -0.204 for men and women, respectively; r = -0.324 for the upper tertile group divided based on their body mass index in women) with the deltaAdiponectin. However, the BW at the baseline examinations was not significantly correlated in both sexes. Multiple logistic regression analyses revealed that subjects who reduced their BW by 2 kg or more were 2.56 (95% confidence interval, 1.21-5.42; P = .014) and 8.24 times (95% confidence interval, 3.59-18.9; P < .001) more likely to be in the upper tertile of the deltaAdiponectin than those who increased their BW by 2 kg or more in men and women, respectively, independent of their BW at the baseline examinations. In conclusion, we showed here that the deltaBW was strongly associated with the deltaAdiponectin in both sexes, whereas the BW at the baseline examinations was not associated with the deltaAdiponectin, at least in women.

Adiponectin↗
PubMed2006

[Participation of the clinical laboratory in the nutrition support team].

Recently, organization of the nutrition support team (NST) is progressing steadily in many hospitals in Japan. In our Yamagata University Hospital, NST services were started in March, 2004. As is well known, NST is a multidisciplinary team comprised of physicians, nurses, dietitians, pharmacists, social workers and medical technologists. Here, we report the participation of medical technologists and physicians belonging to our Clinical laboratory in NST activities. From our laboratory, two medical technologists and two physicians participate in the NST and provide the following services. Firstly, nutritional assessment of proteins in serum i.e. albumin, retinol binding protein (RBP) and transthyretin (TTR) is carried out, measured as part of routine work, and, especially, the data of RBP and TTR are applied to the assessment of nutrition status around the digestive surgical operations. They are also useful to assess the effect of dietary meal, immunonutrition "Impact", which improves the malnutrition status of the pre operative patient. Secondly, a weekly "malnutrition report", including numbers of patients with malnutrition in every ward, serial graphs, and detailed comments on their movements, is reported by e-mail to NST associated departments. This report is conveniently indicates the nutritional situation of inpatients in the hospital and aids consideration of countermeasures for malnutrition in the NST meeting. Thirdly, we medical technologists also participate in making rounds, where we state our opinions on a patient's data, and, if necessary, propose to the chief physician to request additional laboratory tests. We believe that these current activities of our laboratory as part of the NST will contribute to the development of our University NST, raising the quality of nutrition support services, and resulting in improvements of malnutrition and the quality of life of patients.

Medical Laboratory Science↗
PubMed2005

TRPA1 induced in sensory neurons contributes to cold hyperalgesia after inflammation and nerve injury.

Cold hyperalgesia is a well-documented symptom of inflammatory and neuropathic pain; however, the underlying mechanisms of this enhanced sensitivity to cold are poorly understood. A subset of transient receptor potential (TRP) channels mediates thermosensation and is expressed in sensory tissues, such as nociceptors and skin. Here we report that the pharmacological blockade of TRPA1 in primary sensory neurons reversed cold hyperalgesia caused by inflammation and nerve injury. Inflammation and nerve injury increased TRPA1, but not TRPM8, expression in tyrosine kinase A-expressing dorsal root ganglion (DRG) neurons. Intrathecal administration of anti-nerve growth factor (anti-NGF), p38 MAPK inhibitor, or TRPA1 antisense oligodeoxynucleotide decreased the induction of TRPA1 and suppressed inflammation- and nerve injury-induced cold hyperalgesia. Conversely, intrathecal injection of NGF, but not glial cell line-derived neurotrophic factor, increased TRPA1 in DRG neurons through the p38 MAPK pathway. Together, these results demonstrate that an NGF-induced TRPA1 increase in sensory neurons via p38 activation is necessary for cold hyperalgesia. Thus, blocking TRPA1 in sensory neurons might provide a fruitful strategy for treating cold hyperalgesia caused by inflammation and nerve damage.

Animals↗
PubMed2005

Structure and function of TRPV1.

Capsaicin, the main ingredient in hot chili peppers, elicits a sensation of burning pain by selectively activating sensory neurons that convey information about noxious stimuli to the central nervous system. The capsaicin receptor, transient receptor potential vanilloid 1 (TRPV1), is predicted to have six transmembrane (TM) domains and a short, pore-forming hydrophobic stretch between the fifth and sixth TM domains, and is activated not only by capsaicin but also by heat (>43 degrees C), acid and various lipids. Within the TPRV1 protein, many regions and amino acids involved in specific functions (multimerization, capsaicin action, proton action, heat activation, desensitization, permeability, phosphorylation and modulation by lipids) have been identified since the cloning in 1997. Given the fact that TRPV1 is a key molecule in peripheral nociception, these regions and amino acids could prove useful for the development of novel anti-nociceptive or anti-inflammatory agents.

Acids↗
PubMed2005

Association of the ABCA1 gene polymorphisms with type 2 DM in a Japanese population.

To examine the association of the ATP-binding cassette transporter 1 (ABCA1) gene with type 2 diabetes (DM), we studied genetic polymorphisms of the ABCA1 gene including its linkage disequilibrium (LD) and haplotype analyses using a Japanese population. A sample set (DM:72, IGT:75, and NGT:227) was genotyped with 34 SNPs distributed from the promoter region to the last exon of the ABCA1 gene. LD between SNPs was assessed in pairwise manner. Among 13 LD blocks constructed, an LD block at the 5'-region showed a significant difference in the haplotype distribution between the study groups (NGT vs. IGT + DM: overall p = 0.0180; NGT vs. DM: 0.0001). Fisher's exact probability test (NGT vs. DM) showed a significant association of the haplotype 2 of the LD block (p = 0.0001), with an odds ratio (OR) of 2.53 (95%CI:1.62-4.12). Diplotype analysis also showed a significant association of the diplotypes with the haplotype 2 (OR:2.59, 95%CI:1.48-4.54, p = 0.0013).

ATP Binding Cassette Transporter 1↗
PubMed2005

Sensitization of TRPV1 by EP1 and IP reveals peripheral nociceptive mechanism of prostaglandins.

Prostaglandin E2 (PGE2) and prostaglandin I2 (PGI2) are major inflammatory mediators that play important roles in pain sensation and hyperalgesia. The role of their receptors (EP and IP, respectively) in inflammation has been well documented, although the EP receptor subtypes involved in this process and the underlying cellular mechanisms remain to be elucidated. The capsaicin receptor TRPV1 is a nonselective cation channel expressed in sensory neurons and activated by various noxious stimuli. TRPV1 has been reported to be critical for inflammatory pain mediated through PKA- and PKC-dependent pathways. PGE2 or PGI2increased or sensitized TRPV1 responses through EP1 or IP receptors, respectively predominantly in a PKC-dependent manner in both HEK293 cells expressing TRPV1 and mouse DRG neurons. In the presence of PGE2 or PGI2, the temperature threshold for TRPV1 activation was reduced below 35 degrees C, so that temperatures near body temperature are sufficient to activate TRPV1. A PKA-dependent pathway was also involved in the potentiation of TRPV1 through EP4 and IP receptors upon exposure to PGE2 and PGI2, respectively. Both PGE2-induced thermal hyperalgesia and inflammatory nociceptive responses were diminished in TRPV1-deficient mice and EP1-deficient mice. IP receptor involvement was also demonstrated using TRPV1-deficient mice and IP-deficient mice. Thus, the potentiation or sensitization of TRPV1 activity through EP1 or IP activation might be one important mechanism underlying the peripheral nociceptive actions of PGE2 or PGI2.

Animals↗
PubMed2005

Association of decrease in serum dehydroepiandrosterone sulfate levels with the progression to type 2 diabetes in men of a Japanese population: the Funagata Study.

Association of serum dehydroepiandrosterone sulfate (DHEAS) levels with insulin resistance and impairment of insulin secretion have been reported. We here examined the association of serum DHEAS levels with type 2 diabetes mellitus (DM) and the progression to DM. The serum DHEAS levels at baseline (from 1995 to 1997) were evaluated in 1709 individuals (998 women and 711 men) from a cohort population (n = 3706) of the Funagata Study. Glucose tolerance was evaluated at baseline as well as at 5-year follow-up examinations (n = 970, follow-up rate, 56.8%) according to the 1985 World Health Organization criteria. The statistical significance of the difference between any 2 groups was determined by the Student t test. Multiple logistic regression analysis determined the association of the traits with the progression to DM at the 5-year follow-up examinations. P < .05 was accepted as statistically significant. The serum DHEAS levels were significantly lower in DM than in normal glucose tolerance. However, this difference was not significant when adjusted for age. In men, the decrease in serum DHEAS levels by the 5-year follow-up examinations was significantly larger in the subjects who became diabetic than in the subjects who remained normal glucose tolerance, even when adjusted for age ( P = .0003). Multiple logistic regression analysis revealed a significant association of the decrease in serum DHEAS levels with the progression to DM, with an odds ratio (per 0.1 log ng/mL) of 1.410 (95% confidence interval [CI], 1.020-1.948, P = .038), independently from age, height, and 2-hour plasma glucose in men. A decrease in serum DHEAS levels seems to be associated with the progression to DM in Japanese men.

Aged↗
PubMed2005

[Study of the antibodies against measles, rubella, mumps and varicella-zoster viruses in sera from the medical staffs].

For infection control against measles, rubella, mumps and varicella-zoster viruses in the hospital, it is important to assess the immunity of the medical staff against those viruses and to achieve high immunocompetence in the medical staff by vaccination. We estimated the specific antibodies against measles, rubella, mumps and varicella-zoster viruses by ELISA in 686 care workers (240 men, 446 women) of Yamagata University Hospital. The members (frequencies) without antibodies for each virus were 59 (8.6%) for measles virus, 68 (9.9%) for rubella virus, 104 (18.2%) for mumps virus and 5 (0.7%) for varicella-zoster virus. The ratios of positive antibodies, especially against rubella and mumps viruses, were higher among women than men. To see the relationship between the immunity and age, we studied the numbers without antibodies by dividing the persons by age. The numbers of negative IgG for measles virus were 45 (17.5%) in the persons age of 21-30, 8 (4.3%) in 31-40, 4 (2.4%) in 41-50 and 2 (2.7%) in over 51. The numbers of negative IgG for rubella virus were 21 (8.2%) in the persons age of 21-30, 22 (11.7%) in 31-40, 22 (13.2%) in 41-50 and 3 (4.1%) in over 51. The numbers of negative IgG for mumps virus were 35 (13.6%) in the persons age of 21-30, 39 (20.7%) in 31-40, 22 (13.2%) in 41-50 and 8 (10.8%) in over 51. The numbers of negative IgG for varicella-zoster virus were 4 (1.6%) in the persons age of 21-30 and 1 (0.5%) in 31-40. The rate of the persons without antibodies but who had received vaccination in the past were the following: 46% for measles virus, 21% for rubella virus and 21% for mumps. The results of antibodies were informed individually and the persons without antibody against each virus were recommended to receive a vaccination for each virus.

Adult↗
PubMed2005

Japanese standard reference material for JDS Lot 2 haemoglobin A1c. I: Comparison of Japan Diabetes Society-assigned values to those obtained by the Japanese and USA domestic standardization programmes and by the International Federation of Clinical Chemistry reference laboratories.

BACKGROUND: The Committee on Standardization of Laboratory Testing Related to Diabetes Mellitus of the Japan Diabetes Society (JDS) previously recommended use of the primary calibrator (JDS Lot 1) prepared by the former Committee for Standardization of Glycohemoglobin for standardizing the measurement of haemoglobin A1c (HbA1c). Owing to the depletion of vials of Lot 1 in March 2001, the present committee certified a new reference material, Lot 2, now distributed by the Health Care Technology Foundation (HECTEF). The standardization programme for HbA1c measurement in Japan is currently based on Lot 2, which has values assigned from within Lot 1; the Lot 1 values were consensus values based on assays by laboratories in the Japanese national quality control programme. In this study, for the purpose of international comparison and standardization, Lot 2 was assayed by the JDS reference laboratories, the National Glycoprotein Standardization Program (NGSP) in the USA, and by reference laboratories approved by the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC). METHOD: The HbA1c values of JDS Lot 2 were transferred from those assigned to Lot 1 using KO500, a high-resolution HPLC method, at three laboratories approved by the JDS committee. Subsequently, vials of JDS Lot 2 were shipped to and assayed by the NGSP in the USA and 10 IFCC reference laboratories. RESULT: The JDS-assigned HbA1c values (from Lot 1) are 4.04 for Level 1, 5.38 for Level 2, 7.32 for Level 3, 9.88 for Level 4, and 12.63 for Level 5, all expressed as a percentage of total haemoglobin. The values obtained by NGSP and the IFCC laboratories gave the following formulas: NGSP value(%)=JDS value(%)+0.3%; IFCC value(%)=1.068xJDS value(%)-1.741%. CONCLUSION: Although the values obtained by the IFCC laboratories are significantly lower than the values assigned to Lot 2 by the JDS, the relationship is linear. In addition, standardization of HbA1c based on JDS Lot 2 is currently at a satisfactory level in Japan. As a result, the reassignment of values for Lot 2 to agree with the IFCC values should be relatively easy and will be done after all relevant parties agree to the change.

Blood Chemical Analysis↗
PubMed2005

Japanese standard reference material JDS Lot 2 for haemoglobin A1c. II: Present state of standardization of haemoglobin A1c in Japan using the new reference material in routine clinical assays.

BACKGROUND: In 2001, the Committee on Standardization of Laboratory Testing Related to Diabetes Mellitus of the Japan Diabetes Society (JDS) prepared and certified a new reference material for haemoglobin A1c (HbA1c), Lot 2. The standardization programme for HbA1c measurement in Japan is currently based on Lot 2, although some laboratories still use the previous material (Lot 1). The values assigned to Lot 2 were based on the consensus values for Lot 1 and should give the same results. Therefore, there should be no difference in the measured values no matter which calibrators are used. The Committee conducted a domestic survey in order to confirm this relationship. METHOD: In November 2002, four samples for HbA1c assay were sent to 795 laboratories as part of a national survey in Japan. Assays were performed using the laboratories' routine clinical methods. The coefficients of variation (CVs) of the reported values from all laboratories for the samples were calculated in order to determine the current level of standardization in Japan. RESULTS: The overall CVs in the measured values for the four samples ranged from 2.7% to 4.0%. Values from laboratories using calibrators based on Lots 1 and 2 were similar. CONCLUSION: The present state of standardization for the routine measurement of HbA1c in Japan, as indicated by the 2002 survey, is excellent. This should aid in the eventual conversion of Lot 2 to IFCC-based values from the results of the 2002 national HbA1c survey.

Blood Chemical Analysis↗
PubMed2005

Characterization of plasma brain natriuretic peptide level in patients with type 2 diabetes.

This study investigates whether the plasma brain natriuretic peptide (BNP) level is increased by the clinical traits of diabetes, including its complications, and whether these levels are affected by the presence of other combined diseases such as hypertension, hyperlipidemia, and coronary heart disease (CHD) in patients with diabetes. In 223 patients with Type 2 diabetes, the mean value of plasma BNP reached 32.3+/-4.1 pg/mL. The levels significantly increased with age, hypertension, and CHD but not with the duration of diabetes, HbA1c level, or hyperlipidemia. With regard to the type of therapy, the BNP levels were significantly lower in the combinations of both sulfonylurea and metformin and sulfonylurea and pioglitazone than those in insulin alone. In addition, the BNP levels in the group with diabetic complications, including retinopathy and nephropathy, and macroalbuminuria were significantly elevated in comparison with those without these complications and macroalbuminuria. Interestingly, however, no difference was observed between these groups after removal of the values in patients with CHD. These results have clarified that the plasma BNP levels in diabetic patients could increase only by the progression of macrovascular diseases, such as CHD, but not by the current diabetic control or diabetic microvascular complications.

Age Factors↗
PubMed2005

[Cooperation of the clinical laboratory and infection control department in prevention of hospital infections].

Recently, environments that surround hospitals are changing every moment, and hospital infections are no exceptions. As medical technology advances and population of the elderly grow larger steadily, so does the number of immune-compromised hosts. Many patients come to hospitals infected, and in such situations prevention of hospital infections has great amount of importance. Cooperation of microbiological laboratory and ICT is indispensable, accumulation and analysis of the data of resistant bacteria isolated from various medical materials are the biggest task of microbiological lab. Furthermore, nutrition support based on the values of clinical examinations is set as the ultimate goal and NST's cooperation plays a big part in supporting the control of hospital infections.

Cross Infection↗