Quantum-disordered state of magnetic and electric dipoles in an organic Mott system

Strongly enhanced quantum fluctuations often lead to a rich variety of quantum-disordered states. Developing approaches to enhance quantum fluctuations may open paths to realize even more fascinating quantum states. Here, we demonstrate that a coupling of localized spins with the zero-point motion of hydrogen atoms, that is, proton fluctuations in a hydrogen-bonded organic Mott insulator provides a different class of quantum spin liquids (QSLs). We find that divergent dielectric behavior associated with the approach to hydrogen-bond order is suppressed by the quantum proton fluctuations, resulting in a quantum paraelectric (QPE) state. Furthermore, our thermal-transport measurements reveal that a QSL state with gapless spin excitations rapidly emerges upon entering the QPE state. These findings indicate that the quantum proton fluctuations give rise to a QSL—a quantum-disordered state of magnetic and electric dipoles—through the coupling between the electron and proton degrees of freedom.

The organic material κ-H₃(Cat-EDT-TTF)₂ has been suggested to exhibit a quantum spin liquid phase in which quantum fluctuations prevent the formation of magnetic order. Here, the authors show that this may be a result of fluctuations of hydrogen atoms, rather than more conventional geometric frustration.

Collective excitation of an electric dipole on a molecular dimer in an organic dimer-Mott insulator

The terahertz response in 10-100 cm(-1) was investigated in an organic dimer-Mott (DM) insulator κ-(ET)(2)Cu(2)(CN)(3) that exhibits a relaxorlike dielectric anomaly. An ~30 cm(-1) band in the optical conductivity was attributable to collective excitation of the fluctuating intradimer electric dipoles that are formed by an electron correlation. We succeeded in observing photoinduced enhancement of this ~30 cm(-1) band, reflecting the growth of the electric dipole cluster in the DM phase. Such optical responses in κ-(ET)(2)Cu(2)(CN)(3) reflect an instability near the boundary between the DM-ferroelectric charge ordered phases.

Electric polarization, magnetoelectric effect, and orbital state of a layered iron oxide with frustrated geometry

A layered iron oxide RFe2O4 (R denotes rare-earth-metal elements) is an exotic dielectric material with charge-order (CO) driven electric polarization and magnetoelectric effect caused by spin-charge coupling. In this paper, a theory of electronic structure and dielectric property in RFe2O4 is presented. Charge frustration in paired-triangular lattices allows a charge imbalance without inversion symmetry. Spin frustration induces reinforcement of this polar CO by a magnetic ordering. We also analyze an orbital model for the Fe ion which does not show a conventional long-range order.

Electrogene therapy using endostatin, with or without suicide gene therapy, suppresses murine mammary tumor growth and metastasis

Syngeneic inoculated metastatic mammary cancers received direct intratumoral injection of a plasmid vector containing either endostatin (pEndo) with or without a suicide gene (pHSVtk), pHSVtk alone or control vector once a week for 8 weeks. We applied electrogene transfer to the tumors after each injection and administered ganciclovir (GCV) to pHSVtk-transfected mice using an osmotic minipump. Anticancer efficacy was monitored using a variety of parameters, namely tumor volume, intratumoral microvessel density and DNA synthesis, number of mice with metastasis, and number of sites of metastasis per mouse. Tumor volume was significantly lower in all therapeutic groups, with the most effective growth suppression in the pEndo+pHSVtk/GCV group. Lymph node metastasis was significantly less frequent in all therapeutic groups, whereas the multiplicity of lung metastases was significantly lower only in the pEndo and pEndo+pHSVtk/GCV groups. All therapeutic groups showed significantly lower intratumor microvessel density and DNA synthesis. The pEndo and pEndo+pHSVtk/GCV groups also showed a significant reduction in the numbers of dilated lymphatic vessels containing intralumenal tumor cells. Our data suggest that endostatin electrogene therapy alone or in combination with pHSVtk/GCV suicide gene therapy is more beneficial than suicide gene therapy alone. The observed antimetastatic activity of endostatin may be of high clinical significance in the treatment of metastatic breast cancer.

Semen quality of 324 fertile Japanese men

BACKGROUND

A number of studies have indicated regional differences in semen quality. To examine the current status in Japan, we undertook a cross-sectional study on the semen quality of fertile Japanese men for comparison with recent European results.

METHODS

Semen parameters of 324 fertile men from the Kawasaki/Yokohama area were investigated. The semen parameters were compared with those published for fertile men from four European cities, Copenhagen, Paris, Edinburgh and Turku.

RESULTS

When adjusting for confounders such as ejaculation abstinence period and age, the lowest sperm concentrations were detected in men from Kawasaki/Yokohama followed by men from Copenhagen, Paris, Edinburgh and Turku, but only the differences between men from Kawasaki/Yokohama and men from Edinburgh and Turku were significant (P=0.0008 and P<0.0001, respectively). Total sperm count, percentage of motile sperm and percentage of normal sperm observed in Kawasaki/Yokohama were significantly lower than those from all European centres except for motile sperm in men from Paris.

CONCLUSIONS

Japanese fertile men had a semen quality at the level of Danish men, who have been reported to have the lowest among investigated men in Europe. The low level of semen quality of the fertile Japanese men may be due to lifestyle or other environmental factors; however, ethnic differences caused by different genetic variation or combinations cannot be ruled out by this study.

Target validation in hypoxia-induced vascular remodeling using transcriptome/metabolome analysis

The present study describes combined transcriptome and metabolome analysis for therapeutic target validation in hypoxia-induced vascular remodeling. Exposure to hypoxic conditions resulted in the upregulation of S100C mRNA and increased taurine (2-aminoethanesulfonic acid) content in the rat lung, as demonstrated by differential display and amino-acid content analysis. Hypoxia resulted in transcriptional activation of the S100C promoter through hypoxia-inducible factor-1 (HIF-1). Taurine suppressed HIF-1-mediated increases in S100C transcription. Moreover, oral taurine administration attenuated vascular remodeling in hypoxic rat lung, whereas depletion of endogenous taurine by administration of beta-alanine resulted in increased vascular remodeling. Inhibition of HIF transcription by taurine may be of therapeutic benefit in preventing hypoxia-induced vascular remodeling. In conclusion, we used transcriptome and metabolome analysis to identify a therapeutic low-molecular-weight ligand that plays a critical role in hypoxia-induced vascular remodeling. These techniques provided an excellent strategy for screening and validation of targets.

Quantitative effects of respiration on venous return during single knee extension-flexion

Respiration and the muscle pump play major roles in increasing venous return. However, the relative contribution of each of these factors remains unclear. The present study investigates the quantitative effects of interaction between respiration and the muscle pump on femoral venous blood flow (FVBF) during a single voluntary knee extension-flexion (KEF) using duplex-Doppler ultrasound. During various respiration modes, which consisted of arrested respiration, normal respiration and deep respiration (inspiration or expiration), eight subjects performed a supine one-legged voluntary KEF. FVBF was measured during respiration only (Protocol A) and during KEF synchronized with respiration (Protocol B). The difference between FVBF values obtained in Protocol B and Protocol A was defined as DeltaFVBF. When KEF was synchronized with normal or deep respiration, FVBF with inspiration was significantly lower than that with expiration. However, DeltaFVBF was significantly higher with inspiration than with expiration during deep respiration but was not significant during normal respiration. Furthermore, DeltaFVBF was significantly higher at both normal and deep respiration than at arrested respiration. The effects upon the venous return during KEF differed between inspiration and expiration. The present findings indicate that during a single supine KEF, respiration might promote venous return to a range of 1.5- to 2.3-fold DeltaFVBF during arrested respiration.

Functional characterization of naturally occurring mutants (P405R and P425L) of p73alpha and p73beta found in neuroblastoma and lung cancer

The novel candidate tumor suppressor p73, a structural and functional homolog of p53, activates various p53 responsive promoters and induces tumor cell apoptosis. Although p73 is infrequently mutated in human cancers, we have previously found two types of p73 mutation with amino acid substitution (P405R and P425L) in primary neuroblastoma and lung cancer. Here we report generations of the p73 mutants with either P405R or P425L substitution and functional analysis of these naturally occurring mutants. Indirect immunofluorescence staining revealed that nuclear accumulation of p73alpha or p73beta was not affected by these mutations. The P425L substitution reduced the ability of p73alpha to transactivate various p53 responsive promoters (p21(Waf1), Mdm2, and Bax). Moreover, this down-regulation was correlated with the reduced capability of p73alpha(P425L) to suppress cell growth in p53-deficient SAOS-2 cells. In contrast, p73beta(P425L) was as effective as wild-type p73beta in transactivation and growth inhibition. On the other hand, the P405R substitution had no significant effect on both the transcriptional activity and the growth-suppressive ability of p73alpha or p73beta. These results suggested that, at least, one of the naturally occurring p73 mutants, p73alpha(P425L), was a functionally defective mutant of p73.

Pharmacogenomics and therapeutic target validation in cerebral vasospasm

One of the most important pharmacogenomic technologies is transcriptome analysis. We used this method to study the change of gene expression profiles in animal models of cerebral vasospasm. We found novel drug target candidates in cerebral vasospasm through pharmacogenomics. By using differential display and quantitative reverse transcriptase-polymerase chain reaction, we found that heme oxygenase-1 (HO-1) mRNA was prominently induced in the basilar artery and modestly in brain tissue in a murine vasospasm model. There was a significant correlation between the degree of vasospasm and HO-1 mRNA levels in the basilar arteries exhibiting vasospasm. Antisense HO-1 oligodeoxynucleotides (ODN) inhibited HO-1 induction in the basilar arteries, but not in the whole brain tissue. This phenomenon was not observed in the nontreatment, sense HO-1 ODN and scrambled ODN treatment arteries. We report, for the first time, the protective effects of HO-1 gene induction by endogenous or clinical compounds in cerebral vasospasm after subarachnoid hemorrhage, a finding that should provide a novel therapeutic target for cerebral vasospasm.

Usefulness of the combination of pre- and intraoperative selective intraarterial calcium injection to detect residual insulinomas

In a 35-year-old woman diagnosed with insulinoma selective intraarterial calcium injection was positive for proximal gastroduodenal artery and inferior pancreaticoduodenal artery involvement preoperatively. Although non-invasive imaging studies were negative, a mass was detected at the pancreatic uncus by intraoperative ultrasonography. Gastroduodenal artery calcium injection was performed after enucleation of the tumor. Following calcium injection, the insulin level was inappropriately increased and further pancreaticoduodenectomy was performed. After excision, another tumor was detected at the head of the pancreas by histopathological examination. As shown, selective intraarterial calcium injection is useful to localize tumors preoperatively and intraoperatively.

A potent inhibitor of inducible nitric oxide synthase, ONO-1714, a cyclic amidine derivative

(1S,5S,6R,7R)-7-Chloro-3-imino-5-methyl-2-azabicyclo[4.1.0]heptane hydrochloride (ONO-1714), a novel cyclic amidine analogue, inhibits human inducible nitric oxide (iNOS) with a K(i) of 1.88 nM and rodent iNOS with similar potency in vitro. ONO-1714 was found to be 10-fold selective for human iNOS over human endothelial NOS (ecNOS). When the inhibitory activity of ONO-1714 was compared for iNOS, it was found to be 451-fold and >20,000-fold more potent than L-NMMA and aminoguanidine (AG), respectively. In terms of human iNOS selectivity, ONO-1714 was approximately 34- and 2-fold more selective for iNOS than L-NMMA and AG, respectively. ONO-1714 inhibited the LPS-induced elevation of plasma nitrate/nitrite in mice with an ID(50) value of 0.010 mg/kg, s.c. The maximum tolerated dose of ONO-1714 was 30 mg/kg, i.v. Thus, ONO-1714 represents one of the most potent iNOS inhibitors in vitro and in vivo to date and has great potentials for use as an inhibitor for clarifying the pathophysiological roles of iNOS and for use as a therapeutic agent.

The relationship between physical fitness and coronary risk factor profiles in Japanese women

The purpose of this study was to investigate the relationship between physical fitness and coronary risk factor profiles in Japanese women. The subjects were 1,483 women (ages 30 to 69) who participated in a practical health promotion program. After medical examination, physical fitness was evaluated by conducting a symptom limited maximal exercise test by ergometer to measure maximum oxygen uptake (peakVO(2)) with an expired gas analyzer. The subjects were classified into 3 groups (high fitness, moderate fitness, and low fitness) according to age and physical fitness level. The results showed that the subjects in higher fitness groups had lower levels in: body mass index (BMI), percentage of body fat, waist-hip ratio, resting blood pressure, and atherogenic index, and higher HDL-cholesterol compared to those in lower fitness group. Even after adjustment for the effects of age and BMI, die subjects in the higher fitness groups had better coronary risk factor profiles. These results suggest that among Japanese women a high level of physical fitness is related to favorable coronary risk factor profiles.

Ca(2+)-dependent inhibition of actin-activated myosin ATPase activity by S100C (S100A11), a novel member of the S100 protein family

S100C (S100A11, calgizzarin) inhibits the actin-activated myosin Mg(2+)-ATPase activity of smooth muscle in a dose-dependent manner: its half-maximal effect occurs at a S100C/actin molar ratio of 0.05 and its maximal effect occurs at a ratio of 0.20. Furthermore, S100C was found to bind to actin with a stoichiometry of 1:6-7 in the presence of Ca(2+), with an affinity of 1 x 10(-6) M determined by cosedimentation assays. Other Ca(2+)-binding proteins such as S100A1, S100A2, S100B, and calmodulin did not inhibit actin-activated myosin Mg(2+)-ATPase activity. Calmodulin, S100A1, and S100B reversed the inhibitory effect of calponin in a Ca(2+)-dependent manner, S100A2 had no effect, and S100C had additional inhibitory effects. The results suggest that S100C might be involved in the regulation of actin-activated myosin Mg(2+)-ATPase activity through its Ca(2+)-dependent interaction with actin filaments.

Deletion of the COOH-terminal region of p73alpha enhances both its transactivation function and DNA-binding activity but inhibits induction of apoptosis in mammalian cells

The candidate tumor suppressor p73 has a high sequence homology with p53 within the NH2-terminal transactivation domain, the sequence-specific DNA-binding region, and the oligomerization domain. However, p73alpha, which is most abundantly expressed in many tissues and cells among the alternatively spliced forms of p73, has an additional long COOH-terminal tail that might distinguish the function of p53 and p73alpha or other p73 splicing variants. To examine the functional role of the p73alpha COOH-terminal region, we generated a series of p73alpha truncation mutants including p73alpha(1-247) (retaining only a transactivation domain), p73alpha(1-427) (lacking the most COOH-terminal region including a SAM domain), and p73alpha(1-548) (deleting an extreme COOH-terminal region except a SAM domain). When transfected into COS cells, all of p73alpha, p73alpha(1-548), and p73alpha(1-427) localized in the cellular nucleus, whereas p73alpha(1-247) localized in both nucleus and cytoplasm. Intriguingly, when compared with p73alpha, both p73alpha(1-427) and p73alpha(1-548) showed a significant stimulation of the transcription of luciferase reporters harboring three p53-responsive promoters (p21(Waf1), Mdm2, and Bax) in p53-deficient SAOS-2 cells. Gel retardation assays showed that DNA-binding activity of p73alpha(1-427) and p73alpha(1-548) was increased as compared with that of the full-length p73alpha. However, the colony formation assays using SAOS-2 cells demonstrated that, contrary to p73alpha, transfection of p73alpha(1-427) or p73alpha(1-548) resulted in no significant reduction of the number of colonies. These suggest that the distal COOH-terminal region of p73alpha is a cis- or trans-acting regulatory domain and regulates its functions diversely.

Human S100A11 exhibits differential steady-state RNA levels in various tissues and a distinct subcellular localization

In order to analyze the steady-state RNA levels of S100A11 in different tissues, a cDNA fragment of human S100A11 was isolated from a cDNA library. The obtained fragment was labeled and hybridized to RNA isolated from various tissues. The Northern blot analysis revealed that S100A11 RNA levels varied from high in placenta, through intermediate in heart, lung, kidney, and most muscle samples, to barely detectable in brain. An efficient purification method for recombinant S100A11 yielding high quantities was developed. Furthermore, to examine the subcellular localization of this protein, the human polypeptide S100A11 antibodies were raised in rabbit. S100A11 was found to have a localization distinct from other S100 proteins examined, and is mostly localized in the nucleus, with slight variations among different glioblastoma cell types.

Cloning and characterization of rat BAT3 cDNA

HLA-B-associated transcript 3 (BAT3) was originally identified as one of the genes located within human major histocompatibility complex. It encodes a large proline-rich protein with unknown function. In this study, we found that a fragment of the BAT3 gene product interacts with a candidate tumor suppressor, DAN, in the yeast-based two-hybrid system. We cloned the full-length rat BAT3 cDNA from a fibroblast 3Y1 cDNA library. Our sequence analysis has demonstrated that rat BAT3 cDNA is 3617 nucleotides in length and encodes a full-length BAT3 (1098 amino acids) with an estimated molecular mass of 114,801 daltons, which displays an 87.4% identity with human BAT3. The deletion experiment revealed that the N-terminal region (amino acid residues 1-80) of DAN was required for the interaction with BAT3. Green fluorescent protein-tagged BAT3 was largely localized in the cytoplasm of COS cells. Northern hybridization showed that BAT3 mRNA was expressed in all the adult rat tissues examined but predominantly in testis. In addition, the level of BAT3 mRNA expression was more downregulated in some of the transformed cells, including v-mos- and v-Ha-ras-transformed 3Y1 cells, than in the parental cells.

Regulatory mechanisms of calponin phosphorylation in endothelin-1-induced contraction of porcine coronary artery

Calponin is an actin-associated protein that appears to play an auxiliary regulatory role in the contraction of smooth muscle. We report here on the mechanisms for regulation of calponin phosphorylation in the endothelin-1-induced contraction of porcine coronary artery. Treatment of strips of porcine artery with endothelin-1 increased calponin phosphorylation and contraction in a concentration-dependent manner. The time course of the phosphorylation was biphasic, with the response to endothelin-1. The extent of phosphorylation reached a maximum within 5 min of stimulation with 10(-7)M endothelin-1 and then it declined rapidly to reach a minimum at 20 min. A potent inhibitor of protein kinase C, GF109203X, inhibited both calponin phosphorylation and contraction that were induced by endothelin-1 at 5 min, without an inhibition for myosin light chain phosphorylation. Protein phosphatase inhibitor, okadaic acid, had no effect on the extent of phosphorylation at 5 min, but it significantly inhibited the subsequent decrease in calponin phosphorylation. In contrast, in PDBu-treated strips of coronary artery, okadaic acid caused a significant steady increase of the extent of calponin phosphorylation. Our results suggest that calponin phosphorylation might be regulated by protein kinase C and okadaic acid sensitive protein phosphatases, in the endothelin-1-induced contraction of porcine coronary artery.

Repeated writing facilitates children's memory for pseudocharacters and foreign letters

In a logographic language culture, repeated (hand) writing is a common memory strategy for learning letters and Chinese characters. The purpose of this paper is to determine whether this strategy facilitates children's memory for pseudologographic characters and foreign letters. It also explores which aspect of writing, the use of stroke orders or the writing action itself, is responsible for the effect. First, third, and fifth grade Japanese children participated in the study. Results showed that, for all the subjects, characters and letters were better recalled when learned by writing rather than by looking only (Experiments 1 and 4). The advantage of writing was decreased, however, when the proper writing action prevented (i.e., when subjects were instructed to trace or write without feedback; Experiments 3 and 4) but not when the proper stroke orders were prevented (i.e., when subjects were instructed to write in reverse or random orders; Experiment 2). The results indicate that the writing action, rather than the use of stroke orders, is responsible for the effect.

Two distinct actin-binding sites of smooth muscle calponin

Amino acid residues 145-163 of calponin have been proposed as a putative actin-binding site [Mezgueldi, M., Mendre, C., Calas, B., Kassab, R. & Fattoum, A. (1995) J. Biol. Chem. 270, 8867-8876]. Our previous work demonstrated that a fragment of calponin, which corresponded to the first repeated region of calponin and contained the preferred site of phosphorylation by protein kinase C [Nakamura, F., Mino, T., Yamamoto, J., Naka, M. & Tanaka, T. (1993) J. Biol. Chem. 268, 6194-6201] enhanced the Ca2+-induced contraction of permeabilized smooth muscle [Itoh, T., Suzuki, A., Watanabe, Y., Mino, T., Naka, M. & Tanaka, T. (1995) J. Biol. Chem. 270, 20400-20403]. In the present study, we compared the interactions with actin of a synthetic peptide (Lys172-His187) that encompassed the first repeated region with those of three other synthetic peptides. Lys172-His187 inhibited the binding of calponin to F-actin in a concentration-dependent manner but not the binding of caldesmon. Gly141-Gly160, including the above-mentioned putative actin-binding site, also competed with intact calponin to the same extent as Lys172-His187. Inhibition of actomyosin MgATPase activity was observed only with Gly141-Gly160. Lys172-His187 and other tested peptides had no effect. However, Gly141-Gly160 and Lys172-His187 reduced the fluorescence intensity of pyrene-labeled F-actin with approximately equal potency. Moreover, Lys172-His187 was able to reverse the inhibition of actomyosin MgATPase activity by calponin. Lys172-His187 was phosphorylated stoichiometrically by protein kinase C and phosphorylation of this peptide decreased its actin-binding activity. These observations suggest the direct involvement of two distinct actin-binding sites, with different regulatory functions, in the interactions of calponin with actin.

Occurrence of sustained increase in QT dispersion following exercise in patients with residual myocardial ischemia after healing of anterior wall myocardial infarction

Our objective was to evaluate the effect of exercise on QT dispersion over the next 3 hours, as seen on a standard 12-lead electrocardiogram in patients with healed myocardial infarction with or without residual ischemia. We measured QT and QTc dispersion before, immediately after, and 1 and 2 hours after symptom-limited, dynamic treadmill exercise tests in 28 patients with healed anterior wall myocardial infarction with (group I, n = 18) and without (group II, n = 10) residual ischemia. The same protocol was followed in 5 group I patients after successful performance of coronary angioplasty. QT and QTc dispersion did not change immediately after exercise in group II. These parameters increased in group I (QT dispersion at rest [mean +/- SD] 57 +/- 22 ms, and after exercise 87 +/- 27 ms; QTc dispersion at rest 62 +/- 25 ms, and after exercise 114 +/- 36 ms). The increases in QT and QTc dispersion were sustained for at least 2 hours. After a successful coronary angioplasty in 5 patients, these parameters no longer increased with exercise. Thus, QT dispersion increased for at least 2 hours after exercise in patients who had residual ischemia after healing of myocardial infarction. Data obtained in 5 of these patients after coronary angioplasty support the idea that residual ischemia plays a key role in the sustained increase in QT dispersion after exercise.

[Recovery process from myocardial stunning after transient ischemia: assessment with pulsed wave Doppler transmitral flow pattern]

Sustained left ventricular systolic dysfunction after transient myocardial ischemia is well known as "myocardial stunning", but little is known about the recovery in left ventricular diastolic function. Changes in left ventricular systolic and diastolic performance following dobutamine-induced ischemia were investigated in 13 patients with chest pain syndrome and normal coronary arteries (control) and 34 patients with coronary artery disease. Two-dimensional echocardiography and pulsed wave Doppler transmitral flow velocity curves were recorded at baseline, after infusion of a peak dose of dobutamine and at 20 min and 2 hours after dobutamine infusion. In control subjects, left ventricular ejection fraction and the peak early diastolic filling velocity increased at the peak dose of dobutamine. At 20 min after the cessation of dobutamine infusion, these values were restored to the baseline levels. In patients with coronary artery disease, ejection fraction and peak velocity increased at the peak dose of dobutamine but decreased at 20 min after infusion compared with baseline values despite the restoration of heart rate and blood pressure. Although ejection fraction increased at 2 hours compared with 20 min after infusion, peak velocity did not increase. Left ventricular diastolic dysfunction may be sustained longer than systolic dysfunction after transient myocardial ischemia.

Propiverine hydrochloride, an anti-pollakiuric agent, inhibits the activity of actomyosin ATPase from the urinary bladder

The present study was performed to investigate the effects of propiverine hydrochloride (1-methyl-4-piperidyl diphenylpropoxyacetate hydrochloride, P-4), a novel anti-pollakiuric agent, on the contractile proteins of smooth muscle. P-4 (30-300 microM) inhibited the activity of native actomyosin adenosine triphosphatase (ATPase) that had been freshly purified from canine urinary bladder, and calmodulin at 10 microM overcame this inhibition. P-4 also inhibited myosin light chain kinase from smooth muscle in a dose-dependent manner. However, at 300 microM, P-4 was unable to inhibit by 50% the activity of trypsin-treated myosin light chain kinase, which was independent of Ca2+/calmodulin. 1 mol of calmodulin bound 4 to 5 mol of [14C]P-4 in a Ca2+-dependent manner with a K(d) of 77.4 microM. These results indicate that calmodulin is one of the intracellular target molecules for P-4 and that inhibition of the action of calmodulin by P-4 might cause the inhibition of actomyosin ATPase activity, with subsequent relaxation of the smooth muscle of the urinary bladder.

Decreased baroreflex sensitivity in patients with stable coronary artery disease is correlated with the severity of coronary narrowing

Although studies have shown that arterial baroreflex sensitivity (BRS) is decreased in patients with acute myocardial infarction, BRS changes in patients with stable coronary artery disease (CAD) have not been studied extensively. We assessed BRS by the phenylephrine method in 55 normotensive and nondiabetic patients with chronic effort angina, old myocardial infarction, or both. The control group consisted of 24 age-matched patients without coronary lesions. To identify factors that determine BRS in stable CAD, we performed multivariate analysis using age, sex, left ventricular ejection fraction, pulmonary artery wedge pressure, resting systolic blood pressure, resting heart rate, the number of stenotic coronary arteries, history of myocardial infarction, and the presence or absence of angina pectoris as variables. BRS was significantly lower in patients with CAD than in control subjects (5.9 +/- 2.9 vs 6.9 +/- 2.4 ms/mm Hg, p < 0.05). In patients with CAD, BRS was inversely correlated with age, the resting heart rate, and the number of stenotic coronary vessels (p < 0.001, p < 0.005, and p < 0.005, respectively), but was independent of other clinical parameters, including the history of myocardial infarction. In control subjects, BRS was significantly correlated only with age. These results indicate that BRS is decreased in patients with stable CAD, and this decrease is correlated with the extent and severity of coronary narrowing.

Novel specific chemtactic receptor for S100L protein on guinea pig eosinophils

We isolated a new chemotactic protein from bovine lung, and its partial protein sequence analysis indicated that this protein was identical with S100L, one member of the Ca2+-binding S100 protein family. The chemotactic activity of S100L on guinea pig eosinophils is observed at 0.1nM protein concentration, and the effects appear mediated by a novel specific surface receptor. We characterized the receptor for S100L on guinea pig eosinophils. Scatchard analyses of the data that [125I]S100L bound to S100L receptor indicate the presence of two receptor populations on eosinophils with a Kd value of 3.3 x 10(-11)M and 1.1 x 10(-9)M. Thus, S100L protein has the most potent chemotactic activity on guinea pig eosinophils of all the chemotactic proteins.

Contribution of atrial reservoir function to ventricular filling in hypertensive patients. Effects of nifedipine administration

We designed this study to access the importance of left atrial function as a contributor to mitral flow velocity pattern in hypertensive patients. In hypertensive patients the early diastolic flow velocity and ratio of early to late diastolic flow velocity in the mitral flow velocity pattern increase in association with sublingual administration of nifedipine. These changes have been interpreted as signs of improved left ventricular diastolic function; however, the mitral flow velocity pattern is also affected by various other factors. Thus, the nifedipine-induced changes may not necessarily indicate the improvement of left ventricular diastolic function. Transthoracic Doppler echocardiographic parameters of mitral and pulmonary venous flow velocity patterns and left ventricular M-mode echograms were obtained in 16 untreated hypertensive patients before and after sublingual administration of nifedipine (10 mg). Normal values of the parameters were determined in 50 age-matched healthy subjects. After nifedipine peak early diastolic mitral flow velocity increased beyond the normal value, although the peak increasing rate of left ventricular inner dimension, another index of left ventricular diastolic function, did not recover to the normal value. Peak systolic velocity in the pulmonary venous flow velocity pattern increased beyond the normal value, indicating improvement of the reservoir function to the left atrium during systole. Nifedipine-induced normalization of the mitral flow velocity pattern was associated with further abnormalities of the pulmonary venous flow velocity pattern, indicating enhanced left atrial reservoir function.(ABSTRACT TRUNCATED AT 250 WORDS)

A calponin peptide enhances Ca2+ sensitivity of smooth muscle contraction without affecting myosin light chain phosphorylation

In permeabilized smooth muscle, exogenously applied calponin binds to myofibrils and reduces Ca(2+)-activated tension (Itoh, T., Suzuki, S., Suzuki, A., Nakamura, F., Naka, M., and Tanaka, T. (1994) Pflügers Arch. Eur. J. Physiol. 427, 301-308). A calponin peptide (calponin Phe173-Arg185), which inhibits the binding of calponin to actin, blocks the action of calponin and enhances the contraction induced by submaximal Ca2+ in permeabilized vascular smooth muscle. Unlike calmodulin, this peptide enhances the Ca(2+)-induced contraction without a corresponding increase in the level of myosin light chain phosphorylation. These results suggest that calponin decreases the sensitivity of smooth muscle to Ca2+ at a given level of myosin light chain phosphorylation.

Protein kinase C-independent activation of Raf-1 and mitogen-activated protein kinase by leukotriene B4 in guinea pig eosinophils

Leukotriene B4 (LTB4) and phorbol 12-myristate 13-acetate (PMA) were found to activate serine/threonine kinase c-Raf-1 (Raf-1) and mitogen-activated protein (MAP) kinase in guinea pig eosinophils. Raf-1 was activated by both compounds in a time- and dose-dependent fashion, and the activation by each paralleled that of MAP kinase. The LTB4 receptor antagonist ONO-4057 prevented the LTB4-induced activation of Raf-1 and MAP kinase, but had no effect on the PMA-induced activation of these kinases. The protein kinase C (PKC) inhibitors, (+/-)1-O-hexadecyl-2-O-methylglycerol (AMG-C16) and bisindolylmaleimide (GF 109203X), suppressed the PMA-induced activation of Raf-1 and MAP kinase, but not the LTB4-induced activation of both kinases. Our findings suggest that the activation of Raf-1 and MAP kinase by LTB4 involves a PKC-independent pathway.

Increased receptor-mediated phospholipase D activation and Ca2+ mobilization in peritoneal polymorphonuclear leukocytes from streptozotocin-induced diabetic rats

Phospholipase D activation was investigated in peritoneal polymorphonuclear leukocytes from streptozotocin-induced diabetic rats. Stimulation of the cells with formyl-Met-Leu-Phe resulted in a time- and dose-dependent increase in phosphatidylethanol in the presence of ethanol, and this lipid formation in cells prepared from diabetic rats was enhanced as compared to that in the case of nondiabetic rats. Furthermore, the increase in the intracellular Ca2+ concentration was also enhanced in the stimulated cells from diabetic rats. Under the present conditions, N-acetyl-beta-glucosaminidase release and superoxide generation, which are known to be dependent on phospholipase D activation, were higher in the cells from diabetic rats than those in the cells from control rats. However, there was no difference in the dissociation constant and the number of binding sites for formyl-Met-Leu-Phe between the cells from diabetic and control rats. Phosphatidylethanol formation, N-acetyl-beta-glucosaminidase release and superoxide generation in response to ionomycin or 4 beta-phorbol 12-myristate 13-acetate were not enhanced in diabetic rat cells, as compared with those in control rat cells. These results suggest that receptor-mediated phospholipase D activation and Ca2+ mobilization are enhanced in diabetic rat polymorphonuclear leukocytes, which might be due to acceleration of receptor-mediated signaling.

Vasospastic angina pectoris associated with apical hypertrophic cardiomyopathy

As the chest symptoms and electrocardiographic changes of hypertrophic cardiomyopathy are occasionally very similar to those of angina pectoris, there are some difficulties in the diagnosis and treatment of cases of ischemic heart disease associated with hypertrophic cardiomyopathy. Here we report a case of vasospastic angina pectoris associated with hypertrophic cardiomyopathy diagnosed by coronary spasm provocation test performed by intracoronary administration of acetylcholine. In the treatment of such cases, beta blockers, which have the effect of decreasing the oxygen demand of the heart and the potential to induce coronary spasm, must be administered carefully.

Phosphorylation of calponin mediated by protein kinase C in association with contraction in porcine coronary artery

Calponin is an actin-associated regulatory protein in smooth muscle. We report that both endothelin-1 (ET-1) and phorbol 12, 13-dibutyrate (PDBu) caused a significant increase in phosphorylation of calponin during contraction of porcine coronary artery, while high levels of KCl were ineffective. This phosphorylation was predominantly catalyzed by activation of protein kinase C(PKC). In addition, the level of phosphorylation of calponin increased closely in association with the size of the contractile force induced by PDBu. Thus, the phosphorylation of calponin in vivo by PKC might modulate in part the contraction of smooth muscle that occurs in response to ET-1 or PDBu.

The effect of repeated writing on memory

Repeated writing, or rehearsal by writing, is a common memory strategy for the Japanese, especially when learning new logographic characters. The to-be-remembered items are written down not as external prompts, as with reminder notes, but to be memorized in the course of writing them down over and over again. In this study, we investigated whether the strategy was effective, and if so, in which condition. Experiment 1 showed that repeated writing improved memory for graphic designs but not for Chinese characters, words, or syllables. Experiment 2 showed that the effect occurred for both Japanese and American subjects, suggesting that it was not the result of a cultural background associated with a logographic language. Instead, the effect seemed to be accounted for by the encoding specificity of visual-motor information, because repeated writing improved free recall--that included writing--but did not improve recognition (Experiment 3). In Experiment 4, the strategy was applied to learning the Arabic alphabet. Finally, similarities between repeated writing and Type 1 rehearsal are discussed.

Stimulation of platelet-activating factor synthesis in polymorphonuclear leukocytes from streptozotocin-induced diabetic rats

The platelet-activating factor (PAF)-synthesizing capacity was investigated and compared in peritoneal polymorphonuclear leukocytes (PMN) from streptozotocin-induced diabetic and normal rats. PAF synthesis was significantly enhanced in the PMN from diabetic rats compared with that from normal rats stimulated with fMLP. This was manifested as the increased incorporation of [3H]acetate into PAF. Selected ion monitoring/GC/MS analysis revealed that the molecular species of PAF synthesized were mostly of the 1-hexadecyl type, and the amount synthesized in fMLP-stimulated diabetic rat PMN was 1.5 times higher than that in normal rat PMN. The fMLP-induced arachidonic acid liberation resulting from phospholipase A2 activation, was facilitated with a concomitant increase in the cytosolic Ca2+ concentration in diabetic rat PMN. The CoA-independent transacylase activity was similar in both PMN lysates, whereas acetyl-CoA:lyso-PAF acetyltransferase activity was accelerated in the diabetic rat PMN lysate. These results revealed that diabetic rat PMN has more ability to synthesize PAF, presumably due to the large increase in activated phospholipase A2 and acetyltransferase, as well as the increased cytosolic Ca2+ concentration.

Characterization of the myosin-binding subunit of smooth muscle myosin phosphatase

A myosin phosphatase was purified from chicken gizzard smooth muscle. The holoenzyme is a trimer and consists of 130,000-, 38,000-, and 20,000-Da subunits (in agreement with the results of Alessi et al.: Alessi, D., MacDougall, L. K., Sola, M. M., Ikebe, M., and Cohen, P. (1992) Eur. J. Biochem. 210, 1023-1035). The catalytic subunit, 38,000 Da, is the type 1 delta isoform, and its derived amino acid sequence is identical to the rat isoform. The larger subunit bound to myosin and also interacted with the catalytic subunit. cDNA clones encoding the large subunit were isolated from chicken gizzard cDNA libraries. Overlapping clones indicated the presence of two isoforms, and open reading frames of 2889 and 3012 bases were obtained. These encoded proteins of 963 and 1004 amino acids, with masses of 106,700 and 111,600 Da, respectively. The insert in the larger isoform is in the center of the molecule, at residues 512-552. The N-terminal third of the molecule is composed of eight repeat sequences, similar to the cdc10/SWI6 or ankyrin repeat. Myosin binding and binding to the catalytic subunit are properties of a 58,000-Da fragment that represents the N-terminal part of the molecule.

Effect of successful angioplasty following thrombolysis on infarct size and left ventricular function

The role of the angioplasty following thrombolysis in acute myocardial infarction has been discussed in several studies, however the effect of successful angioplasty on infarct size and left ventricular function has not been properly evaluated. Successful reperfusion was achieved in 79 out of 104 patients with primary anterior acute myocardial infarction. These patients were classified as follows, according to the type of intervention during the acute phase: 50 patients in which thrombolysis was successful (the thrombolysis group); 12 patients who underwent successful immediate angioplasty following successful thrombolysis (the immediate angioplasty group); and 17 patients in which rescue angioplasty was successful (the rescue angioplasty group). The 25 patients whose infarct-related vessels were not reperfused after intervention were classified as the non-reperfused group. Infarct size, evaluated as defect volume by T1-201 SPECT, 1 month after the onset, was 840 +/- 154 units (mean +/- S.D.) in the immediate angioplasty group and was similar to that in the thrombolysis group (948 +/- 88 units), but significantly smaller than in the non-reperfused group (1759 +/- 108 units). There were no significant differences in left ventricular function in the immediate angioplasty group and the thrombolysis group. Successful rescue angioplasty did not have any beneficial effect on left ventricular functions or infarct size, when compared with the failed thrombolytic group (1105 +/- 169 units vs. 1617 +/- 169 units). End-diastolic volume (52 +/- 3 ml/m2) in the successful rescue angioplasty group, however, was significantly smaller than in the failed thrombolysis group (67 +/- 3 ml/m2).(ABSTRACT TRUNCATED AT 250 WORDS)

Purification and characterization of a novel calcium-binding protein, S100C, from porcine heart

A novel Ca(2+)-binding protein, which we have named S100C (Ohta et al. (1991) FEBS Lett. 295, 93-96), was purified to homogeneity from porcine heart by Ca(2+)-dependent dye-affinity chromatography. S100C possesses some properties of S100 proteins, such as self-association and exposure of a hydrophobic site upon binding of Ca2+ but it differs from S100 proteins in forms of its isoelectric point (pI = 6.2), cross-reactivity with antibodies, staining by Stains-all, and its Ca(2+)-dependent interaction with the immobilized dye. S100C bound to cytoskeletal components at physiological concentrations of Ca2+. Moreover, it was found that 125I-labeled S100C interacted with annexin I in a Ca(2+)-dependent manner. S100C also inhibited the phosphorylation of annexin I by protein kinase C. These data suggest that S100C might act to regulate the cytoskeleton in a Ca(2+)-dependent manner via interactions with annexin I.

Long-term clinical effect of nilvadipine in patients with chronic heart failure: a double-blind placebo-controlled study

The long-term effect of calcium channel blockers on chronic heart failure is disappointing, probably because of reflex sympathetic activation through arterial vasodilation. However, nilvadipine may be beneficial for treatment of chronic heart failure since this drug has minimal effects on sympathetic activation. In this study, the effects of 12-week administration of nilvadipine or placebo on symptoms of heart failure and cardiac function were investigated in 23 patients with mild-to-moderate chronic heart failure in a double-blind trial. The patients were randomly assigned to either a nilvadipine group (16 mg daily) or a placebo group. Intergroup comparisons did not show significant differences in any parameters. Serious adverse effects were not observed during the study. Thus, this study failed to show any beneficial effect of nilvadipine in the long-term treatment of patients with chronic heart failure. We conclude that the long-term administration of nilvadipine (16 mg daily) is neither effective nor harmful in the treatment of patients with chronic heart failure.

Progressive decreases in coronary vein flow during reperfusion in acute myocardial infarction: clinical documentation of the no reflow phenomenon after successful thrombolysis

OBJECTIVES

This study was undertaken to examine the effects of coronary flow dynamics after thrombolysis on infarct size limitation.

BACKGROUND

It has been commonly accepted that early thrombolysis does not necessarily salvage infarcted myocardium. Plausible causes for myocardial necrosis include such factors as elapsed time to reperfusion, residual stenosis, collateral vessels, hemodynamic loads, preconditioning and reperfusion injury. Recently, the no reflow phenomenon has been elucidated to be associated with infarct extension in clinical studies employing contrast echocardiography or thallium scintigraphy.

METHODS

Nineteen patients with early reperfusion in acute anterior myocardial infarction and comparable clinical background were studied. The patients were classified into two groups on the basis of pattern of thermodilution measurements of great cardiac vein flow after reperfusion: group A, 9 patients with a progressive decrease in great cardiac vein flow during the 1st 24 h of the onset of infarction; and group B, 10 patients without this observation. Left ventricular ejection fraction and thallium perfusion defect were compared between the two groups at follow-up.

RESULTS

There were no significant differences in systemic hemodynamic variables between groups A and B, and neither group had recurrent ischemic events suggesting reocclusion or restenosis during the study. In group A, both great cardiac vein flow (mean +/- SD 44 +/- 17% reduction) and oxygen extraction (38 +/- 15% reduction) were progressively decreased after the onset of reperfusion. Compared with group B, this group showed a lower left ventricular ejection fraction (36 +/- 7% vs. 63 +/- 15%, p < 0.01) and a larger thallium-201 defect severity index (1,091 +/- 366 U vs. 247 +/- 261 U, p < 0.01) at follow-up. Although other patient characteristics were comparable between the two groups, antecedent angina occurred in 90% of group B patients in contrast to only 33% of group A patients.

CONCLUSIONS

Salvage of myocardium from infarction by successful thrombolysis was not observed in the patients demonstrating progressive decreases in great cardiac vein flow (group A). In those patients, inadequate myocardial reperfusion on a microvascular basis might be associated with a much larger myocardial infarction. Antecedent angina may protect against a progressive decrease in coronary flow and may have beneficial effects on infarct size limitation.

Effects of exogenously applied calponin on Ca(2+)-regulated force in skinned smooth muscle of the rabbit mesenteric artery

To help elucidate the physiological role of calponin (a thin-filament-linked regulatory protein) in smooth muscle contraction, the effects of its exogenous application were investigated on actin-activated MgAT-Pase activity in crude actomyosin from chicken gizzard, and on contraction induced by Ca(2+)-dependent and -independent means in arterial smooth muscle strips skinned by saponin or beta-escin. Calponin concentration dependently inhibited actin-activated MgATPase activity with a proportional increase in its binding to actomyosin and also attenuated Ca(2+)-induced contractions, in the presence or absence of calmodulin, in skinned arterial strips. Calponin, when phosphorylated by protein kinase C, reduced both its ability to bind to actomyosin and its inhibitory action on actomyosin MgATPase. The phosphorylated calponin also had no effect on the maximum Ca(2+)-induced contraction in skinned smooth muscle, suggesting that these actions of calponin are not nonspecific. Calponin attenuated the Ca(2+)-independent contraction observed in myosin light chain thio-phosphorylated strips, or on application of trypsin-treated myosin light chain kinase. However, calponin had no effect on maintained rigor contraction. These results suggest that in vascular smooth muscle, calponin may play a physiological role in the inhibition of Ca(2+)-regulated force, possibly through a direct action on active actin-myosin interactions.

Separation and characterization of a novel isoenzyme of cyclic nucleotide phosphodiesterase from rat cerebrum

Anion-exchange chromatography on a Mono-Q column of the supernatant fraction, after ultracentrifugation, from a homogenate of rat cerebrum, prepared under isotonic conditions in the presence of protease inhibitors, yielded a novel isoenzyme of cyclic nucleotide phosphodiesterase (PDE) with properties unlike those of known PDEs. The isoenzyme was insensitive to stimulation by Ca2+/calmodulin and cyclic GMP, and it hydrolyzed both cyclic AMP and cyclic GMP with KM values of 0.109 +/- 0.008 microM and 1.78 +/- 0.04 microM, respectively. The ratio of Vmax of hydrolysis of cyclic GMP to that of cyclic AMP was 1.90 +/- 0.07. Nicardipine (PDE I inhibitor), SK&F 94120 (PDE III inhibitor), rolipram (PDE IV inhibitor) and zaprinast (PDE V inhibitor) had very weak inhibitory effects on the PDE activity of the isoenzyme. These results suggest that the isoenzyme is a novel and previously unreported species of PDE, which we tentatively designate PDE VIII.

Response to octreotide of intestinal pseudoobstruction and pneumatosis cystoides intestinalis associated with progressive systemic sclerosis

Intestinal pseudoobstruction and pneumatosis cystoides intestinalis are uncommon complications of progressive systemic sclerosis. We report a 26-year-old woman with this disorder who responded poorly to conventional treatment. Subcutaneous administration of octreotide, a long-acting somatostatin analogue, at a dose of 50 micrograms/day for 3 weeks, relieved symptoms such as nausea and bloating. There was also a marked decrease of intestinal gas accumulation, as documented on X-ray films.

Calponin phosphatase from smooth muscle: a possible role of type 1 protein phosphatase in smooth muscle relaxation

Smooth muscle myosin bound phosphatase (MBP) purified from chicken gizzard, which is a holoenzyme of type 1 delta protein phosphatase and dephosphorylated intact myosin, catalyzed the dephosphorylation of calponin phosphorylated by protein kinase C (PK-C). The Km of MBP for calponin was 0.6 microM and the Vmax was 350 nmol/min/mg. All of the multiple sites of phosphorylation by PK-C of calponin were completely dephosphorylated by MBP. Functionally, calponin dephosphorylated by MBP recovered its inhibitory effect on the actin-activated Mg(2+)-ATPase activity of myosin. Therefore, these results suggest that a type 1 delta protein phosphatase causes relaxation of smooth muscle by the dephosphorylation not only of myosin but also of calponin.

Thromboxane A2/prostaglandin H2 receptors in streptozotocin-induced diabetes: effects of insulin therapy in the rat

Thromboxane A2 (TXA2) and prostaglandin H2 (PGH2) are potent vasoactive and proaggregatory agents whose synthesis has been shown to be elevated in diabetes mellitus. In the present study the effects of streptozotocin (STZ)-induced uncontrolled diabetes (Severe) and insulin-treated STZ diabetes (Moderate) on TXA2/PGH2 receptor density and affinity in platelets, glomerular membranes and aortic membranes were determined using [125I]-BOP, a TXA2/PGH2 receptor agonist. The affinity and density of platelet TXA2/PGH2 receptors in Control, Moderate and Severe groups and glomerular membranes were not significantly different. However, daily insulin therapy caused significant changes in both TXA2/PGH2 receptor affinity and density of aortic membranes: Kd (nM) = 0.67 +/- 0.09, (n = 5), for Control; 0.27 +/- 0.05*, (n = 6), Moderate; and 0.74 +/- 0.16, (n = 5), Severe; Bmax (fmoles/mg protein) = 38.6 +/- 3.1, Control; 20.2 +/- 4.2*, Moderate; and 37.1 +/- 4.1, Severe: (*p < 0.05 compared to Control and Severe). Contractile responses of aortic segments to the TXA2/PGH2 receptor agonist U46619 were determined. Untreated diabetes mellitus (Severe) was associated with a decreased responsiveness of aortic segments without affecting maximum contractile responses (EC50 = 24.6 +/- 5.9* nM, (n = 10); *p < 0.05) compared to Control rats (EC50 = 11.8 +/- 1.6 nM, (n = 13)). Insulin therapy reversed the decrease seen in the Severe group to a value not different from Control (EC50 = 11.4 +/- 1.2* nM, (n = 10); *p < 0.05 compared to Severe). These results suggest that insulin therapy in the diabetic state significantly influences aortic TXA2/PGH2 receptors, as well as vascular responsiveness to TXA2/PGH2 mimetics.

Identification of the regulatory site in smooth muscle calponin that is phosphorylated by protein kinase C

F-actin and tropomyosin inhibited the phosphorylation of calponin by protein kinase C, and the phosphorylation reduced the binding of calponin to F-actin and tropomyosin. Labeled phosphate from [gamma-32P]ATP was retained both on the chymotryptic NH2-terminal 22-kDa fragment, which contains the actin-, tropomyosin-, and calmodulin-binding regions, and on the COOH-terminal 12-kDa fragment. Fractionation of tryptic 32P-labeled peptides by high performance liquid chromatography allowed isolation of three phosphopeptides (designated T1, T2, and T3), each of which was located in three repeating amino acid motifs of calponin. Both the relative initial rates and extent of phosphorylation decreased in the order T2 > T3 > T1. Both serine and threonine residues were phosphorylated in T1 (GASQAGMTAPGTK), and only a threonine residue was phosphorylated in T2 (FASQQGMTAYGTR) and in T3 (GASQQGMTVYGLPR). As the 22-kDa fragment contained only T2, the phosphorylation site in T2 appeared to regulate the binding of calponin to F-actin and tropomyosin. The amino acid sequence of T2 indicates that protein kinase C phosphorylates Thr184. Thus Thr184 is the preferred site of phosphorylation and is functionally the most important of the sites phosphorylated by protein kinase C in smooth muscle calponin.