Full-Gap Superconductivity Robust against Disorder in Heavy-Fermion CeCu_{2}Si_{2}.

A key aspect of unconventional pairing by the antiferromagnetic spin-fluctuation mechanism is that the superconducting energy gap must have the opposite sign on different parts of the Fermi surface. Recent observations of non-nodal gap structure in the heavy-fermion superconductor CeCu_{2}Si_{2} were then very surprising, given that this material has long been considered a prototypical example of a superconductor where the Cooper pairing is magnetically mediated. Here we present a study of the effect of controlled point defects, introduced by electron irradiation, on the temperature-dependent magnetic penetration depth λ(T) in CeCu_{2}Si_{2}. We find that the fully gapped state is robust against disorder, demonstrating that low-energy bound states, expected for sign-changing gap structures, are not induced by nonmagnetic impurities. This provides bulk evidence for s_{++}-wave superconductivity without sign reversal.

Evaluation of animal models for intestinal first-pass metabolism of drug candidates to be metabolized by CYP3A enzymes via in vivo and in vitro oxidation of midazolam and triazolam.

1. To search an appropriate evaluation methodology for the intestinal first-pass metabolism of new drug candidates, grapefruit juice (GFJ)- and vehicle (tap water)-pretreated mice or rats were orally administered midazolam (MDZ) or triazolam (TRZ), and blood levels of the parent compounds and their metabolites were measured by liquid chromatography/MS/MS. A significant effect of GFJ to elevate the blood levels was observed only for TRZ in mice. 2. In vitro experiments using mouse, rat and human intestinal and hepatic microsomal fractions demonstrated that GFJ suppressed the intestinal microsomal oxidation of MDZ and especially TRZ. Substrate inhibition by MDZ caused reduction in 1'-hydroxylation but not 4-hydroxylation in both intestinal and hepatic microsomal fractions. The kinetic profiles of MDZ oxidation and the substrate inhibition in mouse intestinal and hepatic microsomal fractions were very similar to those in human microsomes but were different from those in rat microsomes. Furthermore, MDZ caused mechanism-based inactivation of cytochrome P450 3A-dependent TRZ 1'-hydroxylation in mouse, rat and human intestinal microsomes with similar potencies. 3. These results are useful information in the analysis of data obtained in mouse and rat for the evaluation of first-pass effects of drug candidates to be metabolized by CYP3A enzymes.

Altered gap junctional communication and renal haemodynamics in Zucker fatty rat model of type 2 diabetes.

AIMS/HYPOTHESIS: We examined the link between altered gap junctional communication and renal haemodynamic abnormalities in diabetes in studies performed on Zucker lean (ZL) and the Zucker diabetic fatty (ZDF) rat model of type 2 diabetes. METHODS: The abundance of connexin (Cx) 37, 40 and 43 was assessed by western blot and immunohistochemistry. Renal haemodynamics was characterised with GAP peptides, which are Cx mimetics, to inhibit gap junctions as a probe in both strains. RESULTS: ZDF rats exhibited higher plasma glucose, 8-epi-prostaglandin F2α excretion, renal plasma flow and GFR than ZL rats. In ZDF rat kidney phosphorylation of Cx43 was enhanced compared with that in ZL rats. Immunohistochemical study revealed that the density of abundance of Cx37 in renin-secreting cells was significantly reduced in ZDF rats. Although renal autoregulation was markedly impaired in ZDF rats, it was preserved in ZL rats. GAP27 for Cx37,43 and for Cx40 impaired renal autoregulation in ZL rats, but failed to induce further alterations in renal autoregulation in ZDF rats. CONCLUSIONS/INTERPRETATION: Our findings indicate that ZDF rats have glomerular hyperfiltration with impaired autoregulation. They also demonstrate enhanced phosphorylation of Cxs and reduced production of Cxs in ZDF rat kidney, especially of Cx37 in renin-secreting cells. Finally, our data suggest that an impairment of gap junctional communication in juxtaglomerular apparatus plays a role in altered renal autoregulation in diabetes.

Strongly correlated superconductivity in a copper-based metal-organic framework with a perfect kagome lattice.

Metal-organic frameworks (MOFs), which are self-assemblies of metal ions and organic ligands, provide a tunable platform to search a new state of matter. A two-dimensional (2D) perfect kagome lattice, whose geometrical frustration is a key to realizing quantum spin liquids, has been formed in the π - d conjugated 2D MOF [Cu3(C6S6)] n (Cu-BHT). The recent discovery of its superconductivity with a critical temperature T c of 0.25 kelvin raises fundamental questions about the nature of electron pairing. Here, we show that Cu-BHT is a strongly correlated unconventional superconductor with extremely low superfluid density. A nonexponential temperature dependence of superfluid density is observed, indicating the possible presence of superconducting gap nodes. The magnitude of superfluid density is much smaller than those in conventional superconductors and follows the Uemura's relation of strongly correlated superconductors. These results imply that the unconventional superconductivity in Cu-BHT originates from electron correlations related to spin fluctuations of kagome lattice.

Separate evaluation of intestinal and hepatic metabolism of three benzodiazepines in rats with cannulated portal and jugular veins: comparison with the profile in non-cannulated mice.

Pharmacokinetic analyses of three kinds of benzodiazepines--midazolam (MDZ), triazolam (TRZ) and alprezolam (APZ)--were performed in rats with cannulated portal and jugular veins. Each drug was administered to the double-cannulated rats, and pharmacokinetic data for the parent drugs and their 1'- and 4-hydroxylated metabolites were compared with those obtained in non-cannulated mice. In bioavailability, the drugs ranked APZ >> TRZ = MDZ in rats, and APZ > TRZ >> MDZ in mice, with the values for MDZ remarkably different between rats and mice (19% in rats versus 2.3% in mice). In contrast, hepatic availability (Fh) was similar (APZ > TRZ > MDZ) in both species. Highly significant relationships were found between the ratio of the area under the plasma concentration-time curve (AUC) for the parent drugs in portal blood (AUC(por)) to that in systemic blood (AUC(sys)) and Fh in rats and mice. The double-cannulated rat is useful for estimating the hepatic availability of drug candidates by determining the AUC values for the parent drugs in portal and systemic blood samples.

Long-term survival of a patient with type A thymoma and Masaoka's stage IV b: case report.

Thymoma is the most common neoplasm in the anterior mediastinum. This report presents an extremely rare case of a type A thymoma with Masaoka's stage IV b due to lymph node metastasis. In 1997, a 59-year-old man underwent complete resection of a stage IV b type A thymoma with postoperative radiotherapy to the mediastinum. In 2006, small nodules were detected in the anterior mediastinum and above the right diaphragm and tumor resection was performed. The two lesions were both histologically diagnosed as recurrences of the type A thymoma. There has been no evidence of recurrence 15 months after the second surgery.

Expression and role of connexins in the rat renal vasculature.

Gap junctions are present in the juxtaglomerular apparatus enabling intercellular communication. Our study determined the location of different connexin subtypes within the juxtaglomerular apparatus of the rat, and the role of these subtypes in renal hemodynamics through the use of specific mimetic peptides. Immunohistochemical analysis showed connexins 37 and 40 expression in the endothelial and renin-secreting cells of the afferent arteriole, while connexin 40 was also found in extra- and intraglomerular mesangial cells. In contrast, connexin 43 was weakly expressed in endothelial cells of the afferent arteriole and within the glomerulus. Intra-renal infusion of the peptides (GAP) reported to block specific gap junctions ((Cx37,43)GAP27 or (Cx40)GAP27), elevated blood pressure, plasma renin activity, and angiotensin II levels, while decreasing renal plasma flow without a significant change in the glomerular filtration rate. Subsequent restoration of blood pressure reduced both renal plasma flow and glomerular filtration rate. In contrast, (Cx43)GAP26 reduced glomerular filtration rate without alterations in blood pressure, renal plasma flow, plasma renin activity, or angiotensin II levels. Hence, connexins 37 and 40 are expressed in the rat juxtaglomerular apparatus and these proteins control, in part, the renin-angiotensin system and renal autoregulation.

Vascular compliance is secured under angiotensin inhibition in non-diabetic chronic kidney diseases.

Cardiovascular diseases constitute major cause of death in chronic kidney diseases (CKDs). We examined the effects of angiotensin inhibition either with angiotensin-converting enzyme inhibitor or with angiotensin receptor blocker on patient prognosis and heart-ankle pulse wave velocity (haPWV) in CKDs. Randomized controlled study was performed on 102 patients with non-diabetic CKDs. Patients were divided into two groups with or without angiotensin inhibition, and followed until death, creatinine clearance was halved or starting renal replacement therapy, whichever occurred first. For 4 years, haPWV was assessed repeatedly in the surviving patients. While both groups showed well blood pressure control throughout 4 years (129+/-1 to 131+/-2/71+/-1 to 73+/-2 mm Hg), renal prognosis was better in angiotensin inhibition group (P<0.05). In addition, angiotensin inhibition reduced cardiovascular and renal death (P<0.05). Age, sex, heart rate, systolic blood pressure and proteinuria were correlated to haPWV (R(2)=0.76, P<0.0001). Although haPWV was similar between two groups at the start of the study (1098+/-31 vs 1094+/-37 cm/s), it was higher in patients without angiotensin inhibition than that with angiotensin inhibition 4 years later (1034+/-38 cm/s (n=28) vs 1242+/-37 cm/s (n=23), P<0.01). The present results provided the evidence that angiotensin inhibition arrested a time-dependent elevation of haPWV in non-diabetic CKDs, conferring organ protection. Furthermore, our data indicated that angiotensin inhibition improved patient prognosis in non-diabetic chronic kidney diseases with mild-to-moderate renal dysfunction.

Attenuated radial augmentation index is associated with successful long-term antihypertensive treatment.

Pulse wave analysis was performed in apparently normal volunteers (n=164) and in essentially hypertensive patients without cardiovascular complications (n=171) using a newly developed non-invasive pulse wave measurement device (HEM-9010AI). Our results suggest that early wave reflections measured by radial augmentation index (AIr) are enhanced in volunteers with systolic blood pressure (SBP) >or= 160 mm Hg compared with the volunteers with their SBP<160 mmHg (98+/-18 vs 88+/-12, P<0.05). Furthermore, AIr is lower in hypertensive patients with long-term antihypertensive treatment than in those with short-term treatment (84+/-10 vs 89+/-13, P<0.01).

Cellular mechanisms mediating rat renal microvascular constriction by angiotensin II.

To assess cellular mechanisms mediating afferent (AA) and efferent arteriolar (EA) constriction by angiotensin II (AngII), experiments were performed using isolated perfused hydronephrotic kidneys. In the first series of studies, AngII (0.3 nM) constricted AAs and EAs by 29+/-3 (n = 8, P < 0.01) and 27+/-3% (n = 8, P < 0.01), respectively. Subsequent addition of nifedipine restored AA but not EA diameter. Manganese (8 mM) reversed EA constriction by 65+/-9% (P < 0.01). In the second group, the addition of N-ethylmaleimide (10 microM), a Gi/Go protein antagonist, abolished AngII- induced EA (n = 6) but not AA constriction (n = 6). In the third series of experiments, treatment with 2-nitro-4-carboxyphenyl-N, N-diphenyl-carbamate (200 microM), a phospholipase C inhibitor, blocked both AA and EA constriction by AngII (n = 6 for each). In the fourth group, thapsigargin (1 microM) prevented AngII-induced AA constriction (n = 8) and attenuated EA constriction (8+/-2% decrease in EA diameter at 0.3 nM AngII, n = 8, P < 0.05). Subsequent addition of manganese (8 mM) reversed EA constriction. Our data provide evidence that in AAs, AngII stimulates phospholipase C with subsequent calcium mobilization that is required to activate voltage-dependent calcium channels. Our results suggest that AngII constricts EAs by activating phospholipase C via the Gi protein family, thereby eliciting both calcium mobilization and calcium entry.

Orientation studies of hydrated dipalmitoylphosphatidylcholine multibilayers by polarized FTIR-ATR spectroscopy.

Polarized Fourier-transform infrared-attenuated total reflection spectroscopy has been applied to explore the temperature-dependence of molecular orientations in multibilayers of 1,2-dipalmitoyl-sn-glycero-3- phosphocholine (DPPC) of various degrees of hydration. The order parameter of the hydrocarbon chain, evaluated from the dichroic ratios of the antisymmetric and symmetric CH2 stretching bands, was drastically decreased at the main (or gel to liquid-crystalline phase) transition temperature (Tm) irrespective of the water content, suggesting that the hydrocarbon chain is in a disordered state as a result of chain-melting associated with an increase in the number of the gauche conformers. On the other hand, the dichroic ratios of the polar bands of hydrated DPPC assignable to the symmetric PO2- stretching and asymmetric N+ (CH3)3 stretching modes were increased mainly at the pretransition temperature (Tp), except for less hydrated case. The dichroic ratios of both the OH stretching and OH2 bending bands of water showed the same temperature-dependence as those of the polar bands. These results indicate that the pretransition is ascribable mainly to the reorientation of the polar groups of the DPPC and bound water, while the main transition is due to the orientational disorder of the hydrocarbon chains. For less hydrated DPPC, the reorientation of the polar groups and water did not occur around Tp, but in the higher temperature region around Tm. This is in accord with the previously reported observation that the pretransition disappears for less hydrated DPPC. In this case, the polar groups and water may reorient following the reorientation of the hydrocarbon chains near Tm.

Orientation of gramicidin D incorporated into phospholipid multibilayers: a Fourier transform infrared-attenuated total reflection spectroscopic study.

Polarized Fourier transform infrared (FTIR)-attenuated total reflection (ATR) spectroscopy was applied to study the orientation of the linear pentadecapeptide antibiotic gramicidin D incorporated into phospholipid multibilayers, which were cast on a germanium ATR plate from chloroform solution. In DMPC and DPPC multibilayers, the CH2 stretching bands of lipid hydrocarbon chains were slightly shifted to the higher frequency side and bandwidth was increased in the presence of gramicidin. However, in DPPE multibilayers, frequencies and bandwidths of these bands were unaltered. In each case, gramicidin produced little effect on the orientation of lipid hydrocarbon chains, suggesting that gramicidin penetrates into lipid layers without noticeable perturbations. Upon incubation of cast films in contact with water above the gel-liquid-crystalline transition temperature (Tc) of lipids, the reorientation of gramicidin in lipid multibilayers occurred, the degree thereof depending upon the fluidity of the lipid hydrocarbon chains and the amount of surrounding water. In DMPC multibilayers, the helix axis of gramicidin was oriented almost parallel to the lipid hydrocarbon chains after incubation. In DPPC multibilayers, on the other hand, the helix axis of gramicidin was tilted on average about 15 degrees from the lipid hydrocarbon chains after incubation. However, in DPPE multibilayers, which are known to have the most rigid bilayer structures, the reorientation of gramicidin could not be seen.

Fourier transform infrared-attenuated total reflection spectroscopy of hydration of dimyristoylphosphatidylcholine multibilayers.

The effect of hydration on the structure and molecular orientation of multibilayers of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC), cast on a germanium plate, was studied by means of polarized Fourier transform infrared (FT-IR)-attenuated total reflection spectroscopy. Compared with the dry state, the antisymmetric and symmetric CH2 stretching bands of fully hydrated DMPC in the liquid-crystalline state were shifted to the higher frequency side, indicating the increase in the number of the gauche conformers. However, the dichroism of these bands revealed that the hydrocarbon chains of DMPC were still ordered and titled. The absorption bands of the glycerol ester, phosphoryl, and choline groups were broadened upon hydration, suggesting the activation of the librational or torsional motion. Furthermore, the dichroism of the polar head group bands of DMPC indicated that these groups retained a slight orientation even in the fully hydrated and fluid multibilayers.

Spin-state equilibrium in the model complexes of azide hemoprotein.

Addition of NaN3 to ferric protohemin biscoordinated with 1-methylimidazole (1-MeIm) or 2-methylimidazole (2-MeIm) in (CH3)2SO resulted in sizeable visible absorption changes, corresponding to the formation of the mixed ligand complexes, hemin X N-3 X 1-MeIm and hemin X N-3 X 2-MeIm. The visible absorption spectrum of the 1-MeIm complex was closely similar to those of azide hemoproteins, while the 2-MeIm derivative exhibited intensified 500 and 625 nm bands and depressed 540 and 570 nm peaks. The iron-bound N-3 of the model complexes exhibited two infrared stretching bands, which were assigned to the high- and low-spin peaks. The intensity of the high-spin infrared peaks increased at higher temperature. From the analyses of the infrared spectral changes, the thermodynamic values of the thermal spin equilibria were determined to be delta H = -3920 cal/mol and delta S = -11.1 e.u. for hemin X N-3 X 1-MeIm and delta H = -2150 cal/mol and delta S = 7.9 e.u. for hemin X N-3 X 2-MeIm. The thermodynamic values of the 1-MeIm complex are similar to the reported values for azide metmyoglobin, suggesting that the contribution from the nonbonded porphyrin-globin contacts to the spin equilibrium is small in azide metmyoglobin. Comparison of the delta H and delta S values among model systems indicates that delta H and delta S compensation similar to that observed in hemoprotein also holds in the models. This may suggest an underlying common denominator for the spin-equilibrium mechanisms in hemins and hemoproteins.

A comparative study on interactions of alpha-aminoisobutyric acid containing antibiotic peptides, trichopolyn I and hypelcin A with phosphatidylcholine bilayers.

Interactions of alpha-aminoisobutyric acid containing antibiotic peptides, trichopolyn I and hypelcin A with phosphatidylcholine bilayers were investigated to obtain some basic information on their bioactive mechanisms. Trichopolyn I as well as hypelcin A induced the leakage of a fluorescent dye, calcein, entrapped in sonicated egg yolk L-alpha-phosphatidylcholine vesicles. A quantitative analysis revealed that both the binding affinity and the 'membrane-perturbing activity' of trichopolyn I to the vesicles are about one-third of those of hypelcin A. The conformations and the orientations of the peptide and lipid molecules in the membranes were studied using polarized Fourier transform infrared-attenuated total reflection spectroscopy, circular dichroism, and differential scanning calorimetry. In phosphatidylcholine bilayers, both peptides mainly conformed to helical structures irrespective of the membrane physical state (gel or liquid-crystalline). The helix axes, penetrating the hydrophobic region of the bilayers, were oriented neither parallel nor perpendicular to the membrane normal. The disruption in the lipid packing induced by the peptide insertion seems to be responsible for the leakage by these peptides.

Flavocetin-A and -B, two high molecular mass glycoprotein Ib binding proteins with high affinity purified from Trimeresurus flavoviridis venom, inhibit platelet aggregation at high shear stress.

Two high molecular mass proteins, flavocetin-A and flavocetin-B, were purified from Trimeresurus flavoviridis venom. On polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate, the apparent molecular mass of flavocetin-A and -B were 149 and 139 kDa, respectively, under nonreducing conditions. On reduction, flavocetin-A showed two distinct subunits (17 and 14 kDa), and flavocetin-B three distinct subunits (17, 15 and 14 kDa). At 1 microgram/ml, flavocetin-A and -B (flavocetins) inhibited the von Willebrand factor (vWF)-dependent aggregation of fixed human platelets. However, flavocetins (10 micrograms/ml) had no effect on ADP- and collagen-induced platelet aggregation in PRP. Flavocetins (3 micrograms/ml) also inhibited shear-induced platelet aggregation at high shear stress. Furthermore, flavocetin-A completely inhibited the aggregation of and ATP release from washed platelets stimulated with a low concentration of thrombin. Flavocetin-A specifically bound to platelet with high affinity (Kd = 0.35 +/- 0.13 nM) at 21,500 +/- 1760 binding sites per platelet. The N-terminal amino acid sequences of the subunits of flavocetin-A show a high degree of homology with those of echicetin, botrocetin, alboaggregin-B and factor IX/factor X-binding protein. These results suggest that flavocetins may be a useful tool for further investigation of the GPIb-vWF interaction.

Prevalence of Anderson-Fabry disease in male patients with late onset hypertrophic cardiomyopathy.

BACKGROUND: Although studies have suggested that "late-onset" hypertrophic cardiomyopathy (HCM) may be caused by sarcomeric protein gene mutations, the cause of HCM in the majority of patients is unknown. This study determined the prevalence of a potentially treatable cause of hypertrophy, Anderson-Fabry disease, in a HCM referral population. METHODS AND RESULTS: Plasma alpha-galactosidase A (alpha-Gal) was measured in 79 men with HCM who were diagnosed at > or =40 years of age (52.9+/-7.7 years; range, 40-71 years) and in 74 men who were diagnosed at <40 years (25.9+/-9.2 years; range, 8-39 years). Five patients (6.3%) with late-onset disease and 1 patient (1.4%) diagnosed at <40 years had low alpha-Gal activity. Of these 6 patients, 3 had angina, 4 were in New York Heart Association class 2, 5 had palpitations, and 2 had a history of syncope. Hypertrophy was concentric in 5 patients and asymmetric in 1 patient. One patient had left ventricular outflow tract obstruction. All patients with low alpha-Gal activity had alpha-Gal gene mutations. CONCLUSION: Anderson-Fabry disease should be considered in all cases of unexplained hypertrophy. Its recognition is important given the advent of specific replacement enzyme therapy.

Morphology and electrophysiological properties of squid giant axons perfused intracellularly with protease solution.

Squid giant axons were perfused intracellularly with solutions containing various kinds of proteases (1 mg/ml). Except for a 10 micro layer inside the axolemma the axoplasm was removed by a 5 min perfusion with Bacillus protease, strain N' (BPN'). The resting and action potentials were unchanged and the axon maintained its excitability for more than 4 hr on subsequent enzyme-free perfusion. After perfusion with protease solution for 30 min the axoplasm was almost completely removed. The excitability was maintained, but the action potential became prolonged and rapidly developed a plateau of several hundred milliseconds. The change was not reversible even when the enzyme was removed from the perfusing fluid. Two other enzymes, prozyme and bromelin, also removed the protoplasm without blocking conduction. Trypsin suppressed within 3 min the excitability of the axon. It is suggested that the proteases alter macromolecules in the excitable membrane and thus affect the shape of the action potential.