Changes in the awareness of oral health among new students newly enrolled at the University of Tokyo over the past 15 years.

OBJECTIVE: The aim of this study was to examine changes in awareness of oral health among Japanese university students. METHODS: Between 1990 and 2004, a total of 51,650 students newly enrolled at the University of Tokyo responded to an annual written questionnaire on oral health. RESULTS: (i) Approximately 60% of the students brushed their teeth twice a day. Female students brushed more frequently than male students. (ii) The percentage of students who brushed for 2-3 min per time decreased, while the percentage who brushed four or more minutes increased. (iii) The number of students who had learned how to brush properly increased. This trend was particularly clear-cut among male students, although the proportion of female students who had learned to brush properly remained higher than that of male students. (iv) The percentage of female students who sought treatment for malocclusion was higher than that of male students. The percentage of students who underwent orthodontic treatment increased from 11.6 to 19.7%. The percentage of female students who received orthodontic treatment was approximately twofold that of male students. (v) The percentage of students who had temporomandibular disorders was 0.7% in males and 1.5% in females. (vi) More than 40% of the students had periodontal diseases, with a higher prevalence among male students than female students. (vii) Approximately 20% of the students wanted to consult our service centre. CONCLUSIONS: The awareness of oral health among new undergraduates at the University of Tokyo has improved over the past 15 years.

High fidelity SNP genotyping using sequence-specific primer elongation and fluorescence correlation spectroscopy.

Reliable, efficient and cost-effective modalities are urgently needed for mass screening of gene mutations. Previous reports have shown that SSCP or genechip methods require substantial time and monetary costs, thus limiting their appeal. Sequence Specific Primer Polymerase Chain Reaction (SSP-PCR) is a reliable and cost-effective method that utilizes the 3'-end discrimination properties of polymerase. However, the applicability of conventional SSP-PCR is limited due to the difficulties associated with determining optimal conditions and because mis-matched primers are amplified, resulting in signal noise during end-point assay. To overcome this problem, we eliminated the reverse primers from SSP-PCR, thus preventing amplification of mis-matched primers. We designated this method Sequence-Specific Primer Cycle Elongation (SSPCE). However, the detection of elongated sequence specific primers was difficult using conventional electrophoresis due to the small amounts of amplification product present. We therefore combined SSPCE and Fluorescence Correlation Spectroscopy, which is a novel technique used to determine the number and size of fluorophores at nano-molar concentrations, and designated the method SSPCE-FCS. We compared conventional SSP-PCR and SSPCE-FCS with regard to determining optimal conditions using two Mitochondrial SNPs (G --> A at position 1598, G --> A at position 12192). We were able to determine the optimal conditions for the SNP at position 1598 using either method. However, optimal conditions could only be determined for SSPCE-FCS with the 12192 mutation because non-specific amplification was observed at a wide range of annealing temperatures in SSP-PCR. We then applied this method to three other SNPs and the results were consistent with the results of sequencing data.

Simultaneous determination of morphine and its glucuronides in rat hair and rat plasma by reversed-phase liquid chromatography with electrospray ionization mass spectrometry.

The simultaneous determination of morphine and the glucuronide metabolites [morphine-3-beta-D-glucuronide (M3G) and morphine-6-beta-D-glucuronide (M6G)] in rat hair and rat plasma was carried out using reversed-phase high-performance liquid chromatography (HPLC) coupled with electrospray ionization mass spectrometry (ESI-MS). The chromatographic separation of the analytes was achieved using a semi-micro-HPLC column (3 microm particle size; 100 x 2.0 mm id) by gradient elution with 50 mM ammonium acetate and acetonitrile as eluents. After separation, morphine and the glucuronides were determined by selected ion monitoring (SIM) of ESI-MS using the quasi-molecular ions [M + H]+ at m/z = 286 and 462, respectively. The calibration curves were linear between the concentration of the analytes and the deuterium-labelled morphine (M-d3) selected as internal standard. The method was applied for the determination of the incorporation of morphine and the glucuronides into the hair shafts and hair roots of Dark Agouti rats after single intraperitoneal administration of morphine hydrochloride. Plasma concentrations of morphine and glucuronides were simultaneously determined after administration. Morphine and M3G were detected in the hair shafts and the hair roots. The concentrations of M3G in the hair root were lower than those of morphine in all sampling periods. In contrast, M3G concentrations in plasma were relatively higher at each sampling time. Small quantities of M6G were also identified in the plasma up to 4 h after administration. The concentration difference between the hair root and plasma seems to be due to the incorporation ratio of morphine and glucuronide into hair. As M3G was also identified in the hair shaft 1 week after administration, the incorporation of glucuronide metabolites into hair is obvious. This is the first report of the identification of morphine glucuronide in hair samples without the use of acid hydrolysis or enzyme digestion.

Determination of triazolam involving its hydroxy metabolites in hair shaft and hair root by reversed-phase liquid chromatography with electrospray ionization mass spectrometry and application to human hair analysis.

A sensitive method using reversed-phase liquid chromatography coupled with electrospray ionization mass spectrometry has been developed for simultaneous determination of triazolam and its hydroxy metabolites in hair. After the addition of deuterium-labeled 1-hydroxymethyltriazolam as an internal standard, the analytes in hair shaft and hair root samples were extracted with a basic medium, CH(2)Cl(2):MeOH:28% NH(4)OH (20:80:2) at room temperature overnight. The chromatographic separation of the analytes was achieved using a semimicro HPLC column (3-microm particle size; 100 x 2.0-mm i.d.) by gradient elution with acetonitrile in water containing 1% acetic acid as eluent. The mass spectrometer was operated in selected-ion monitoring mode at quasi-molecular ions [M+H](+) of triazolam and its metabolites. The method has been applied to determine the incorporation of triazolam and its metabolites into the hair shafts and hair roots of Dark Agouti rats administered 3 or 6 mg/kg triazolam intraperitoneally twice a day for 5 days. Triazolam, 1-hydroxymethyltriazolam, and 4-hydroxytriazolam were incorporated into the hair shafts and the hair roots. The concentration of 4-hydroxytriazolam was the highest of all compounds detected. An unknown substance considered to be 1,4-dihydroxytriazolam also appeared in the hair samples. The structural elucidation was performed with online HPLC-MS after acetylation of the substance with acetic anhydride and pyridine. The time course studies of triazolam and the metabolites in both rat hair roots and plasma were carried out after single intraperitoneal administration of triazolam. The concentrations of triazolam and the metabolites in the hair roots reflected those in the plasma. The proposed method using selected-reaction monitoring was applied to the determination of triazolam and the metabolites in human hairs of a triazolam addict. Triazolam, 1-hydroxymethyltriazolam, and 4-hydroxytriazolam were identified in the black hair shafts, whereas only triazolam was detected in the hair roots and the white hair shafts. This is the first report on the detection of triazolam and its metabolites in human hairs.

Determination of rat hepatocellular glutathione by reversed-phase liquid chromatography with fluorescence detection and cytotoxicity evaluation of environmental pollutants based on the concentration change.

Three methods for the determination of rat hepatocellular thiols by high-performance liquid chromatography (HPLC) with fluorescence (FL) detection have been developed. The thiols in the cells were tagged with three fluorogenic reagents, SBD-F, ABD-F and DBD-F. These reagents could permeate into cells and effectively reacted with thiols to produce highly fluorescent derivatives. These derivatives fluoresced in the long wavelength region at around 530 nm (excitation at around 380 nm). The five biological thiols tagged were perfectly separated by reversed-phase liquid chromatography and were sensitively and selectively detected without any interference from endogenous substanaces. The main thiol in the cells was reduced GSH and the concentration was at the mM level. The proposed procedures were applied to the determination of hepatocellular GSH after treatment of environmental pollutants such as volatile organic compounds (VOC) and endocrine disrupting chemicals (EDC). From the comparison of intracellular GSH concentration, the test compounds were classified into four groups: compounds of strong depletion (eg triphenyltin chloride, hexachlorocyclohexene, nonylphenol, bromoacetic acid, 4-chlorobenzyl chloride and 1,3-dichloropropene), slight decrease (eg bisphenol A, benzo[a]pylene, carbon tetrachloride and benzene), slight increase (eg bromoform and toluene), and no effect (eg 1,1,1-trichloroethane, 1,1,2-trichloroethane and 1,2-dichloroethane). Although the decrease of GSH concentration does not reflect the cytotoxicity of chemicals, the proposed procedure utilizing isolated rat hepatpcytes seems to be useful for investigating the bioactivation of VOC, and EDC, etc.

Morphological and physiological restorations of hereditary form of dilated cardiomyopathy by somatic gene therapy.

TO-2 strain hamsters with dilated cardiomyopathy, gene deletion of delta-sarcoglycan (SG) and no expression of alpha-, beta-, gamma-, and delta-SG proteins are useful for developing the potential gene therapy of intractable heart failure. We prepared recombinant adeno-associated virus vector including normal delta-SG gene driven by CMV promoter and intramurally administered in vivo. The transfected myocardium induced robust expression of both transcript and transgene for 2/3 period of the animal's life expectancy. Immunostaining demonstrated reexpression of not only delta-SG but also other three SGs in 40% cells in the transfected region and normalization of the diameter of transduced cardiomyocytes. Hemodynamic study revealed preferential amelioration of the diastolic indices (LVEDP, the dP/dt(min) and CVP). These results provide the first evidence that supplementation of a specific gene with efficient and sustained transfection capability restores the genetic, morphological, and functional deteriorations.

R(-)-4-(3-Isothiocyanatopyrrolidin-1-yl)-7-(N,N-dimethylaminosulfonyl)-2,1,3-benzoxadiazole, a fluorescent chiral tagging reagent: sensitive resolution of chiral amines and amino acids by reversed-phase liquid chromatography.

The usefulness of R(-)-4-(3-isothiocyanatopyrrolidin-1-yl)-7-(N,N-dimethylaminosulfonyl)-2,1,3-benzoxadiazole [R(-)-DBD-PyNCS], a fluorescent chiral tagging reagent, for the determination of racemic amines and amino acids, was studied. The reagent reacted with beta-blockers selected as representative secondary amines to produce corresponding fluorescent diastereomers (excitation at 460 nm and emission at 550 nm). The yields of the derivatization reaction were dependent on the stereostructure arround the NH group in beta-blockers. The resulting diastereomers were completely separated with single chromatographic run using linear gradient elutions by reversed-phase chromatography. R(-)-DBD-PyNCS was also applied to the determination of DL-amino acid, considered to be one of the primary amines, in human urine and foodstuffs. DL-amino acids tested equally reacted with the reagent, and the thiocarbamoyl derivatives were separated with an ODS column. The epimerization during the derivatization reaction was negligible judging from the resolution of opposite diastereomers on the chromatogram. The occurence of D-amino acids (D-Ala, D-Ser, D-Asp and/or D-Glu) was identified in the samples tested. The structures and the purities were elucidated with on-line HPLC-MS. The chiral reagent possessing an isothiocyanate group (-NCS) in the structure seems to be applicable to continuous sequential analysis of peptides containing D-amino acids. The thiocarbamoyl derivatives obtained from the reaction with DL-amino acids were converted to thiohydantoins via thiazolinones in acidic medium. The thiohydantoins produced from acidic, basic, neutral, hydroxyl and aromatic amino acids were completely separated with isocratic elutions using acidic mobile phase containing 0.1% TFA. The separations were sufficient for the identification of DL-amino acid in peptide sequences. Although the epimerization during the conversion reaction to thiohydantoins was not avoidable, the descrimination of D- and L-configuration was demonstrated with some commercially available peptides such as beta-lipotropin and [D-Ala2]-deltorphin II. The Edman degaradation method using R(-)-DBD-PyNCS was also adopted to autoanlaysis by gas-phase sequencer. The separation and the detection (UV 254 nm) conditions of the derivatives were used without any change from those for the Edman degradation method using PITC as the tagging reagent. The three DL-amino acid residues (Tyr, Ala and Gly) in [L-Ala2]-leucine-enkephalin and [D-Ala2]-leucine-enkephalin were perfectly identidied with the autoanalysis.

Crucial role of type 1, but not type 3, inositol 1,4,5-trisphosphate (IP(3)) receptors in IP(3)-induced Ca(2+) release, capacitative Ca(2+) entry, and proliferation of A7r5 vascular smooth muscle cells.

Stimulation of G protein- or tyrosine kinase-coupled receptors regulates cell proliferation through intracellular Ca(2+) ([Ca(2+)](i)) signaling. In A7r5 cells, we confirmed that inositol 1,4,5-trisphosphate (IP(3)) mediates vasopressin (VP)-evoked Ca(2+) release from intracellular stores and showed that types 1 (IP(3)R(1)) and 3 (IP(3)R(3)) IP(3) receptors were expressed. Using antisera selective for IP(3)R(1) or IP(3)R(3) and another that interacted equally well with both subtypes, together with membranes from SF:9 cells expressing only single IP(3)R subtypes to calibrate immunoblotting, we established that A7r5 cells express 81% IP(3)R(1) and 19% IP(3)R(3). To elucidate the contributions of IP(3)R(1) and IP(3)R(3) to Ca(2+) signaling and proliferation, stable clones expressing promoter-inducible antisense cDNA fragments (-90 to +9) corresponding to the two IP(3)R subtypes were selected. Mild inhibition of IP(3)R(1) (71+/-8% of control level) slightly attenuated the IP(3)-evoked Ca(2+) release (IICR) induced by VP but significantly decreased the subsequent capacitative Ca(2+) entry (CCE) and proliferation. Moderate inhibition (34+/-6%) strongly decreased both IICR and CCE and further blocked proliferation. Complete inhibition almost abolished IICR and CCE and arrested proliferation entirely. Complete inhibition of IP(3)R(3) expression slightly attenuated IICR without affecting CCE or proliferation. In cells microinjected with a low dose of heparin, VP-induced CCE was more susceptible than IICR to mild inhibition of both IP(3)R(1) and IP(3)R(3). A high dose of heparin had a similar effect to complete inhibition of IP(3)R(1) expression: it blocked VP-evoked IICR entirely and CCE by 90%. We conclude that IP(3)R(1), but not IP(3)R(3), is crucial for IICR, CCE, and proliferation of vascular smooth muscle cells.

A novel homoplasmic mutation in mtDNA with a single evolutionary origin as a risk factor for cardiomyopathy.

To clarify the relationship between variation in mtDNA and the development of cardiomyopathy (CM), the complete sequences of mtDNAs of two brothers with dilated CM were compared with those of 181 patients who had CM and with those of 168 control subjects. Five patients with CM shared a novel homoplasmic point mutation (G12192A tRNA(His)), and all of them demonstrated the evolutionarily related D-loop sequence. The results suggest that this novel mutation originated from the same ancestor and that its presence strongly predisposes carriers to CM.

Evaluation of the heart with magnetic resonance imaging.

After compensating for two kinds of motion artifacts caused by cardiac beating and respiration, cardiac magnetic resonance (MR) imaging is now feasible for the diagnosis of various cardiac diseases. Taking cost-effectiveness into consideration, this paper reviews the experiences of preferable indications of cardiac MR imaging by demonstrating the characteristic preciseness and uniqueness that play an important role in obtaining time-volume curves consisting of the theoretically most accurate measurements of left and right ventricular volumes, in overall evaluation of the left ventricular apex and the right ventricle, in delineating the wide range of the coronary arterial tree, in measuring the most precise blood flow volume through the cross-sectional images of the vessels, and in assessing the spatial derivative of the blood flow velocity at the vessel wall, i.e., wall shear rate.

Bile acids increase intracellular Ca(2+) concentration and nitric oxide production in vascular endothelial cells.

The effects of bile acids on intracellular Ca(2+) concentration [Ca(2+)](i) and nitric oxide production were investigated in vascular endothelial cells. Whole-cell patch clamp techniques and fluorescence measurements of [Ca(2+)](i) were applied in vascular endothelial cells obtained from human umbilical and calf aortic endothelial cells. Nitric oxide released was determined by measuring the concentration of NO(2)(-). Deoxycholic acid, chenodeoxycholic acid and the taurine conjugates increased [Ca(2+)](i) concentration-dependently, while cholic acid showed no significant effect. These effects resulted from the first mobilization of Ca(2+) from an inositol 1,4,5-triphosphate (IP(3))-sensitive store, which was released by ATP, then followed by Ca(2+) influx. Both bile acids and ATP induced the activation of Ca(2+)-dependent K(+) current. Oscillations of [Ca(2+)](i) were occasionally monitored with the Ca(2+)-dependent K(+) current in voltage-clamped cells and Ca(2+) measurements of single cells. The intracellular perfusion of heparin completely abolished the ATP effect, but failed to inhibit the bile acid effect. Deoxycholic acid and chenodeoxycholic acid enhanced NO(2)(-) production concentration-dependently, while cholic acid did not enhance it. The bile acids-induced nitric oxide production was suppressed by N(G)-nitro-L-arginine methyl ester, exclusion of extracellular Ca(2+) or N-(6-aminohexyl)-5-chloro-l-naphthalenesulphonamide hydrochloride (W-7) and calmidazolium, calmodulin inhibitors. These results provide novel evidence showing that bile acids increase [Ca(2+)](i) and subsequently nitric oxide production in vascular endothelial cells. The nitric oxide production induced by bile acids may be involved in the pathogenesis of circulatory abnormalities in liver diseases including cirrhosis.

[Mitochondrial gene mutation].

Mitochondrial DNA(mtDNA) anomaly was emerging as a cause of idiopathic cardiomyopathy in addition to sarcomeric gene mutation. Meanwhile, several point mutations and deletions in mtDNA initially recognized as major causes of mitochondrial encephalomyopathies are now clarified to share 1% cause of diabetes mellitus. These results indicate that mtDNA mutations will be a significant candidate for cardiomyopathies. Screening of cardiomyopathic patients with mtDNA point mutations revealed that there were at least several % of mtDNA anomaly (MELAS type) among them. They also showed specific findings in ultrastructures of the cardiac muscle.

Autocrine action and its underlying mechanism of nitric oxide on intracellular Ca2+ homeostasis in vascular endothelial cells.

The rise in cytosolic Ca(2+) concentration (Ca(2+)(i)) in vascular endothelial cells (ECs) activates the production and release of nitric oxide (NO). NO modifies Ca(2+)(i) homeostasis in many types of nonendothelial cells. However, its effect on endothelial Ca(2+)(i) homeostasis at basal and excited states remains unclear. In the present study, to elucidate the effect of NO on basal Ca(2+)(i), inositol 1,4,5-trisphosphate-induced Ca(2+)(i) release (IICR) was blocked by expressing an antisense against type-1 inositol 1,4,5-trisphosphate receptors or by microinjecting heparin to individual ECs, and the effects of NO that was released by and diffused from adjacent IICR-intact ECs were recorded. After ATP or bradykinin stimulation, IICR-inhibited ECs showed a marked reduction of basal Ca(2+)(i), which was abolished by N(G)-monomethyl-l-arginine monoacetate pretreatment. The reduction disappeared in sparsely seeded ECs. Exogenous NO gas mimicked the effect of ATP or bradykinin to reduce basal Ca(2+)(i). Blocking plasma membrane Ca(2+)-ATPase (PMCA), but not Na(+)-Ca(2+) exchange or sarcoplasmic/endoplasmic reticulum Ca(2+)-ATPase, suppressed the reduction, indicating that the reduction resulted from a NO-dependent potentiation of PMCA. To elucidate the effect of NO on elevated Ca(2+)(i), ATP-, bradykinin-, or thapsigargin-evoked Ca(2+)(i) response in the presence and absence of NO production was compared in adjacent IICR-intact ECs. NO was found to potentiate PMCA, which, in turn, greatly attenuated agonist-evoked Ca(2+)(i) elevation. NO also potentiated Ca(2+) influx, which markedly increased the sustained phase of Ca(2+)(i) elevation and possibly NO production. NO did not affect other Ca(2+)(i)-elevating and Ca(2+)(i)-sequestrating components. Thus, NO-dependent potentiation of PMCA is crucial for Ca(2+)(i) homeostasis over a wide Ca(2+)(i) range.

Peroxynitrite production by TNF-alpha and IL-1beta: implication for suppression of osteoblastic differentiation.

To determine the roles of nitric oxide (NO) and its metabolite, peroxynitrite (ONOO(-)), on osteoblastic activation, we investigated the effects of a NO donor [ethanamine, 2, 2'-(hydroxynitrosohydrazono)bis- (dNO)], an O(-2) donor (pyrogallol), and an ONOO(-) scavenger (urate) on alkaline phosphatase (ALPase) activity and osteocalcin gene expression, which are indexes of osteoblastic differentiation. dNO elevated ALPase activity in the osteogenic MC3T3-E1 cell line. The combination of dNO and pyrogallol reduced both ALPase activity and osteocalcin gene expression. Because both indexes were recovered by urate, ONOO(-), unlike NO itself, inhibited the osteoblastic differentiation. Furthermore, treatment with a combination of the proinflammatory cytokines tumor necrosis factor-alpha (TNF-alpha) and interleukin-1beta (IL-1beta) was found to yield ONOO(-) as well as NO and O(-2). The reductions in ALPase activity and osteocalcin gene expression were also restored by urate. We conclude that ONOO(-) produced by TNF-alpha and IL-1beta, but not NO per se, would overcome the stimulatory effect of NO on osteoblastic activity and inhibit osteoblastic differentiation.

Dystrophin disruption might be related to myocardial cell apoptosis caused by isoproterenol.

Sarcolemma integrity is stabilized by the dystrophin-associated glycoprotein complex that connects actin and laminin-2 in contractile machinery and the extracellular matrix, respectively. Interruption of the connection by the primary gene defect or acquired pathological burden can cause cardiac failure. The purposes of the present study were to verify whether dystrophin is disrupted in acute myocardial injury after the isoproterenol overload (10 mg/kg) and to examine its relation to myocardial cell apoptosis in rats. This injury from 4-16 h at the subendocardium was accompanied by dystrophin disruption and dislocation from subsarcolemma to cytoplasm, which were confirmed by immunohistology and Western blotting. However, delta-sarcoglycan was thoroughly preserved in sarcolemma. The dystrophin degradation preceded the appearance of apoptotic cells and exactly coincided with the transferase-mediated dUTP-biotin nick end labeling-positive cardiomyocytes (TUNEL), as was verified by double-staining. These data suggest that beta-adrenergic stimulation induces dystrophin breakdown followed by apoptosis.

Separation of 17 DL-amino acids and chiral sequential analysis of peptides by reversed-phase liquid chromatography after labeling with R(-)-4- (3-isothiocyanatopyrrolidin-1-yl)-7-(N, N-dimethylaminosulfonyl)-2,1,3-benzoxadiazole.

Seventeen DL-amino acids labeled with a fluorescent chiral labeling reagent, R(-)-4-(3-isothiocyanatopyrrolidin-1-yl)-7-(N, N-dimethylaminosulfonyl)-2,1,3-benzoxadiazole (R(-)-DBD-PyNCS), were separated by reversed-phase chromatography and detected fluorometrically at 550 nm (excitation at 460 nm). The reagent reacted with amino functional group in dl-amino acids under basic medium. The thiocarbamoyl derivatives were converted to thiohydantoin via thiazolinone in trifluoroacetic acid (TFA) solution. The epimerization ratios during the reaction of the cyclization were less than 37% in all dl-amino acids tested. The resulting thiohydantoin derivatives of individual dl-amino acids were completely separated with isocratic elutions using acidic mobile phase involving 0.1% TFA. The separations of the thiohydantoins yielded from acidic, basic, neutral, hydroxyl, and aromatic amino acids were good enough for the identification of dl-amino acid. The method using the reagent was adopted to identification of dl-amino acid sequences in eight peptides. The separation and identification of the thiohydantoin derivatives liberated from the peptides labeled were performed by the isocratic elutions. The applicability of the proposed procedure to sequential analysis of peptide was demonstrated with [D-Ala(2)]-leucine enkephalin, [D-Ala(2)]-deltorphin II, d-Phe-Met-Arg-Phe-amide, and Phe-D-Met-Arg-Phe-amide. D-Ala, D-Phe, and D-Met in the peptides were positively identified with the proposed procedures. [L-Ala(2)]-leucine enkephalin, beta-lipotropin, Asp-Ser-Asp-Pro-Arg, and Pro-Asp-Val-Asp-His-Val-Phe-Leu-Arg-Phe-amide were also analyzed as the references without D-amino acid.

Strain- and age-dependent loss of sarcoglycan complex in cardiomyopathic hamster hearts and its re-expression by delta-sarcoglycan gene transfer in vivo.

The delta-sarcoglycan (SG) gene is deleted in hamsters with hereditary cardiomyopathies. Immunological analyses of heart before, but not after, the progression of cardiomyopathy (CM) revealed that the BIO 14.6 strain, a model of hypertrophic CM, heterogeneously preserved alpha- and gamma-SG with loss of beta- and delta-SG. In contrast, the TO-2 strain, a model of dilated CM, did not show either SG. Furthermore, in vivo transfer of the full length delta-SG gene to TO-2 hearts expressed all four SGs. Thus, this age- and strain-dependent features suggest a more feasible setting for TO-2 than BIO 14.6 to verify both CM progression and the efficacy of gene therapy.

Long-term inhibition of renin-angiotensin system sustains memory function in aged Dahl rats.

The Dahl salt-sensitive (DS) rat, a genetic model of salt-induced hypertension in humans, is more likely to develop severe vascular injuries than a rat with spontaneous hypertension. We designed an experiment to scrutinize the effects of renin-angiotensin inhibition on cognitive dysfunction in the aged, normotensive DS with a passive avoidance test. Eighteen months of treatment with a very low dose of the angiotensin-converting enzyme (ACE) inhibitor cilazapril (2.5 microg/mL in drinking water) or the angiotensin II type 1 receptor antagonist E4177 did not reduce blood pressure throughout the experiment, although in the low dose cilazapril group (12.5 microg/mL in drinking water), blood pressure dropped within 6 months after treatment began. The cilazapril treatments dose-dependently improved memory function in the aged, normotensive DS fed a low-salt diet compared with the untreated, control rats. This improvement was associated with significant increases in hippocampal CA1 cells and capillary densities in the CA1 regions compared with those in the untreated DS. Similarly, E4177 slightly improved the memory dysfunction observed in the aged DS. The cells in the hippocampal CA1 region were restored slightly, but the capillary densities were not influenced by the receptor antagonist. On the other hand, the ACE inhibitor and receptor antagonist both attenuated urinary protein excretions with an improvement of glomerular sclerosis. These data suggest that long-term treatment with an ACE inhibitor improves memory dysfunction probably through restoration of capillary and hippocampal cells. The effects are due to the inhibition of the angiotensin II type 1 receptor and probably to the enhancement of the kallikrein-kinin system.

Eicosapentaenoic acid inhibits vasopressin-activated Ca2+ influx and cell proliferation in rat aortic smooth muscle cell lines.

The purpose of this study was to clarify how eicosapentaenoic acid (EPA), an omega-3 polyunsaturated fatty acid, modulates the vascular action of vasopressin in rat aortic smooth muscle cell lines. The effects of EPA on Ca2+ mobilization and DNA synthesis elicited by vasopressin were investigated and compared to those of Ca2+ channel blocking agents, by means of Ca2+ measurements and the incorporation of [3H]thymidine. Patch-clamp techniques were also employed. Vasopressin (100 nM) elicited an initial peak of intracellular Ca2+ ([Ca2+]i), followed by a sustained phase due to Ca2+ entry. Nifedipine or nicardipine (1 microM), a potent L-type Ca2+ channel blocker, partly inhibited the sustained phase, but La3+ completely abolished it. EPA (10 microM) also inhibited it even in the presence of nicardipine. Under voltage-clamp conditions with CsCl-internal solution, depolarizing pulses positive to -30 mV from a holding potential of -40 mV elicited a slow inward current. The inward current was blocked by La3+, nicardipine, and nifedipine (1 microM), suggesting that the inward current mainly consisted of the voltage-dependent L-type Ca2+ channel (ICa.L). EPA (1-30 microM) also inhibited ICa.L in a concentration-dependent manner. The inhibitory effect of EPA was observed at concentrations higher than 1 microM, and its half-maximal inhibitory concentration (IC50) was 7.6 microM. Vasopressin induced a long-lasting inward current at a holding potential of -40 mV. The vasopressin-induced current was considered as a non-selective cation current (Icat) with a reversal potential of approximately +0 mV. Both nifedipine and nicardipine (10 microM) failed to inhibit it significantly, but La3+ completely abolished Icat. EPA also inhibited vasopressin-induced Icat in a concentration-dependent manner; its IC50 value was 5.9 microM. Vasopressin (100 nM) stimulated [3H]thymidine incorporation. Exclusion of extracellular Ca2+ with EGTA or La3+ markedly inhibited it. EPA (3-30 microM) also inhibited the incorporation induced by vasopressin, while nifedipine and nicardipine (1 microM) only partly inhibited it. These results suggested that EPA, unlike nifedipine and nicardipine, inhibited vasopressin-induced Ca2+-entry and proliferation in rat vascular smooth muscle cells, where the inhibitory effects of EPA on Icat as well as ICa.L might be involved. Thus, EPA would exert hypotensive and antiatherosclerotic effects.

High salt intake potentiates the renal vascular and glomerular damage caused by low doses of angiotensin II in uni-nephrectomized rats.

OBJECTIVE: We recently reported that the renin-angiotensin system plays an important role in the progression of vascular and kidney injuries, even in Dahl salt-sensitive rats with volume-dependent hypertension. In this study, we investigated whether a high-salt diet increases susceptibility to kidney injury induced by angiotensin II in normotensive, uni-nephrectomized Sprague-Dawley rats, which mimics the condition of salt-volume repletion and blunted renin-angiotensin system. METHODS: The rats were fed either a low-salt (0.3% NaCl) or a high-salt (4% NaCl) diet and divided into five groups: two control groups with a low-salt or a high-salt diet without angiotensin II infusion (saline infusion), and three angiotensin II groups (angiotensin II infusion, 10 or 50 ng/kg per min with high-salt diet, 50 ng/kg per min with low-salt diet, subcutaneously). The rats were kept on these regimes for 8 weeks. The blood pressure was measured every week. Functional and morphological alterations in the kidney were assessed at the end of the experiment RESULTS: There were no differences in the arterial blood pressures of the five experimental groups. However, angiotensin II infusion increased the weights of the heart and aortic walls in a dose-dependent manner in the high-salt groups. There was also a dose-dependent increase in proteinuria, N-acetyl-beta-D-glucosaminidase activity (NAG) excretion, and additional glomerular and arterial injuries in the kidney, associated with angiotensin II infusion in the high-salt groups. In the rats given a higher dose of angiotensin II, the high-salt diet significantly increased the weights of the heart and aortic walls and exacerbated the renal function and morphological injuries, compared to the low-salt group. High-salt diet alone increased the kidney and heart weights. However, it did not significantly influence the results of the morphological and functional study. On the other hand, angiotensin II infusion on a low-salt diet showed a trend towards glomerular damage; however, the effects were small and not significant. Similarly, there were few effects of angiotensin II infusion on morphology and functional study on a low-salt diet CONCLUSION: These data clearly show that a high-salt intake increases susceptibility of the kidney to injuries induced by low doses of angiotensin II in normotensive, uni-nephrectomized rats.