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.

Characterization of non-linear relationship between total and unbound serum concentrations of valproic acid in epileptic children.

OBJECTIVE: To establish a regression equation to properly estimate the unbound serum concentration of valproic acid (VPA) from its total serum concentration; the relationship between total and unbound serum VPA concentrations was retrospectively characterized. METHODS: Data were obtained from the clinical examination records that were routinely archived during therapeutic drug monitoring. The screening encompassed 342 records of 108 paediatric patients whose total and unbound VPA concentrations had been determined. The relationship between total and unbound VPA concentrations was characterized according to the Langmuir equation by taking account of inter-individual variability with the nonmem program. RESULTS: The total VPA concentration (C(t)) in the screened patients ranged from 5.5 to 179.8 microg/mL, and the unbound VPA concentration (C(f)) increased in a non-linear manner as the total VPA concentration increased. Taking account of the effects of antiepileptics concurrently administered, the VPA dissociation constant (K(d)) and maximum binding site concentration (B(m)) were 7.8 +/- 0.7 and 130 +/- 4.5 microg/mL respectively, for the regression equation, C(t) = C(f) + B(m) x C(f)/(K(d) + C(f)). An alteration in the unbound concentration was seen in patients who were treated with the combination of VPA and ethosuximide and in those who received two additional antiepileptics. CONCLUSIONS: A regression equation for estimation of the unbound VPA concentration, based on total VPA concentration collected during routine therapeutic drug monitoring was established. Use of two additional antiepileptics and ethosuximide treatment was considered as potential factors affecting unbound VPA concentration.

Novel antigen expression on syngeneic somatic cell hybrids of murine spontaneous mammary tumor cells.

Spontaneous mammary carcinoma cells of C3H/He mice were fused with syngeneic L-cells, and two types of hybrid cell clones were obtained. In group A, hybrid cells showed contact inhibition, and parental H-2k and L-antigens were well expressed. Metacentric chromosomes of L-cell origin and estrogen dependency were also well preserved in this group. However, in group B, hybrid cells proliferated to pile up, and the expression of parental antigens, H-2 and L-cell antigens, was strongly suppressed. But, mouse mammary tumor antigens (MM-antigens), which were expressed on ascites mammary tumor cells with hypotetraploidy of C3H/He origin and which were not expressed on both parent cells, were newly expressed. The number of metacentric chromosomes was decreased, and estrogen dependency was lost in this group. The relationship between the expression of MM-antigens and that of H-2 antigens was reciprocal, and tumorigenicity was independent of cellular behavior in vitro and of MM-antigen expression. MM-antigen-positive hybrid cell clones were frequently obtained when tumor cells were fused with metaphase-rich L-cells.

Molecular organization of hepatocyte peroxisomes.

The matrix of peroxisomes has been considered to be homogeneous. However, a fine network of tubules is visible in electron micrographs at very high magnification. This substructure becomes more positive in a high-contrast photocopy and with an imaging-plate method. Clofibrate, bezafibrate, and aspirin increase peroxisomes. In proliferated peroxisomes, the density of matrix is low and the fine network is more visible. The effect of proliferators is more significant in males than in females. This sex difference may involve the action of estrogen, growth hormone, cytochrome P-450 and thyroxine. Mg-ATPase is localized on the limiting membrane of peroxisomes. Even on the membrane of irregular projections of proliferated peroxisomes, Mg-ATPase is evident cytochemically. Carnitine acetyltransferase is detectable in the matrix of proliferated peroxisomes. Withdrawal of proliferators results in a rapid decrease of peroxisomes. This may indicate the existence of peroxisome suppressors. Alternatively, dynamic transformation of vesicular to tubular types in peroxisome reticulum may occur. Such transformation has been described in lysosomes and mitochondria.

Remnant-like particle cholesterol, triglycerides, and insulin resistance in nonobese Japanese type 2 diabetic patients.

OBJECTIVE: The aim of the study was to investigate the relationships between remnant-like particle (RLP) cholesterol, triglycerides, and insulin resistance in nonobese Japanese type 2 diabetic patients. RESEARCH DESIGN AND METHODS: A total of 86 nonobese Japanese type 2 diabetic patients (72 men and 14 women, aged 40-83 years, BMI 20.1-26.6 kg/m2) were studied. BMI, HbA1c levels, and fasting concentrations of plasma glucose, serum lipids (RLP cholesterol, total cholesterol, HDL cholesterol, and triglycerides), and serum insulin were measured. Insulin resistance was estimated by the homeostasis model assessment (HOMA-IR). The subjects were divided into two groups according to the value of HOMA-IR. Values >2.5 were indicative of the insulin-resistant state, and values <2.5 were indicative of the insulin-sensitive state. RESULTS: The insulin-resistant group had significantly higher RLP cholesterol and triglyceride levels and lower HDL cholesterol levels compared with the insulin-sensitive group. Univariate regression analysis showed that insulin resistance was positively correlated with BMI (r = 0.254, P = 0.019), HbA1c levels (r = 0.278, P = 0.011), RLP cholesterol levels (r = 0.315, P = 0.004), and triglyceride levels (r = 0.332, P = 0.002) and was negatively correlated with HDL cholesterol levels (r = -0.301, P = 0.006) in our diabetic patients. Multiple regression analysis showed that insulin resistance was independently associated with serum triglyceride levels, which explained 13.5% of the variability of insulin resistance in our nonobese Japanese type 2 diabetic patients. CONCLUSIONS: These results indicate that 1) nonobese Japanese type 2 diabetic patients with insulin resistance are characterized by high RLP cholesterol and triglyceride levels, and low HDL cholesterol levels; and 2) the level of serum triglycerides is an independent predictor of insulin resistance in these patients.

Calcium detection in secretion granules of avian oviduct by scanning electron microscopy (SEM) and energy-dispersive X-ray microanalysis (EDX).

Secretion granules in the shell gland, isthmus, and albumin-secreting region of the hen oviduct were analyzed with WET-scanning electron microscopy (SEM) and EDX, a combination of wide-angle backscattered electron detector (BED) and energy-dispersive X-ray microanalyzer (EDX). Glutaraldehyde-fixed but unhydrated, unstained, and uncoated samples were analyzed; Ca was localized in all secretion granules in all three sections of the hen oviduct studied.

Intracellular localization of migration inhibitory factor-related protein (MRP) and detection of cell surface MRP binding sites on human leukemia cell lines.

The migration inhibitory factor-related proteins (MRPs) MRP-8 and MRP-14 were detected in differentiated human leukemia cell lines (THP-1 and HL-60) by immunocytochemical analysis. They were induced and colocalized in the cytoplasm and in lesser amounts in the nucleus when THP-1 and HL-60 cells were induced to differentiate by 1alpha,25-dihydroxyvitamin D3 or retinoic acid. In a search for a protein capable of binding MRPs, both MRPs were individually produced in insect cells (Sf21) infected with recombinant baculovirus. The purified recombinant MRPs were electrophoretically and antigenically indistinguishable from the native proteins, and their ability to form the MRP8/14 complex was retained. The presence of MRP binding sites was investigated by a binding assay using recombinant MRPs and specific monoclonal antibodies. MRP binding sites were detected on the cell membrane of the human leukemia cell lines THP-1, Raji, and MOLT-4. HL-60 cells treated with 1alpha, 25-dihydroxyvitamin D3 did not express MRP binding sites on the cell membrane, but a high level of MRPs accumulated in the cells. The occurrence of MRP binding sites on the cell surface of leukemia cell lines of monocyte and lymphocyte origin suggests that MRPs, released from neutrophils under certain conditions, may contribute to the activation and recruitment of effector cells to inflammatory lesions.

What effect does controlling platelets have on atherosclerosis?

Platelets play important roles for hemostasis with activated platelets adhering to the injured vessel wall to initiate platelet aggregation. At the same time, our study revealed the cytotoxic effect on endothelial cells characterized by an increase of intracellular Ca++ and a decrease of EDRF production, which may cause plasmal infiltration including blood cells and lipids. Our clinical survey using a small dose of aspirin as an antiplatelet therapy clearly demonstrated its suppressive effect on platelet aggregation and its favorable effect on fibrinolysis. These data suggest that the therapeutic effect of aspirin in vascular disease could be applied to the prevention of thrombus formation and the protection of endothelial cells from the cytotoxic effect of activated platelets.

New assay for glycated lipoproteins by high-performance liquid chromatography.

We developed an automated analytic system for glycated lipoprotein using high-performance liquid chromatography (HPLC) with an affinity boronate column and a gel permeation column. This system can measure glycated lipoprotein (glycated LDL and glycated HDL) in a small (5 microliters) sample of serum in a short time (40 min/sample). Recovery with this system was 92.1%. Therefore a large number of samples can be measured in clinical use. The system should contribute to an elucidation of the role of glycated lipoprotein in atherosclerosis.

Change of the sex-dependent response to clofibrate in F344 rat liver during postnatal development.

Although it has been reported that male rats are more responsive than females to peroxisome proliferation induced by clofibrate, these sex differences have been confirmed in young adult rats. Using 4-, 8-, and 12-week-old F344 rats, postnatal change of the sex-dependent response to clofibrate was investigated. These animals were administered 200 mg/kg body wt./day clofibrate by gavage for 7 days. In 4-week-old rats clofibrate-dependent changes (hepatomegaly, induction of hepatic microsomal and peroxisomal enzymes, proliferation of smooth endoplasmic reticulum and peroxisomes of hepatocytes) were slight in both sexes. In 8- and 12-week-old rats clofibrate-induced changes of males were moderate, whereas those of females were slight. These results suggest that the responsiveness of immature rat to clofibrate is weak and in males the susceptibility is gradually strong during postnatal development.

Age-related changes in the susceptibility to clofibric acid, a hypolipidemic agent, of male rat liver.

Age-related changes in the susceptibility to clofibric acid were investigated in male F344 rats of 8, 52, and 117 weeks old. Hepatomegaly, decrease of serum total cholesterol and triglyceride, increase of the total cytochrome P-450 contents, induction of the activities of microsomal omega-hydroxylation and peroxisomal beta-oxidation, proliferation of smooth endoplasmic reticulum and peroxisomes were detected in 8- and 52-week-old rats. In 117-week-old rats clofibric acid treatment resulted in decrease of serum total cholesterol, elevation of the activities of microsomal and peroxisomal enzymes, and slight proliferation of peroxisomes. These results suggest that the susceptibility of the male F344 rat liver to clofibric acid decreases in 117-week-old rats, though the effect is still recognizable.

Micronucleus test with 6-mercaptopurine monohydrate administered intraperitoneally and orally.

The effect of route of administration on the induction of micronucleated polychromatic erythrocytes (MNPCEs) was examined. 6-Mercaptopurine monohydrate (6-MP) was administered intraperitoneally (i.p.) or orally (p.o.) to 2 strains of mice, MS/Ae and CD-1. From the results of an acute toxicity test and a pilot micronucleus test, the doses selected for the final micronucleus test were 12.5-100 mg/kg for the i.p. route and 25-200 mg/kg for the p.o. route. The sampling time was 48 h. Frequencies of MNPCEs increased dose-dependently by the i.p. route but peaked at 50 or 100 mg/kg for the p.o. route. 6-MP induced MNPCEs more efficiently after p.o. administration than after i.p. treatment in both strains.

The micronucleus test using peripheral blood reticulocytes from methotrexate-treated mice.

The induction of micronuclei by methotrexate (MTX) was examined in two laboratories using mouse peripheral blood reticulocytes. MTX was a weak inducer in the micronucleus test using bone marrow cells and single treatments, and was one of the few chemicals showing a multiple-treatment effect (CSGMT/JEMS.MMS, 1990). In our preliminary experiments, the ratio of reticulocytes to total erythrocytes decreased greatly after a single treatment with MTX at 100 mg/kg, so lower dose levels of MTX were selected to carry out the micronucleus test in peripheral blood. Full-scale tests were performed at dose levels of 0, 10, 20, 40, and 80 mg/kg, with five sampling times of 0, 24, 48, 72, and 96 h. Frequencies of micronucleated reticulocytes (MNRETs) increased dose-dependently at 72 h, to a maximum of approximately 1%; some preparations obtained from the animals at higher doses could not be examined because the ratio of reticulocytes to total erythrocytes had decreased severely. At doses of 0.5-4.0 mg/kg, the effect of multiple treatments vs. single treatments was not clear, nor was the maximum level of response much different. Since MTX induced a clear positive response in peripheral blood reticulocytes after a single treatment, the reticulocytes in peripheral blood seem a more sensitive target.

Mechanism of induction of micronuclei and chromosome aberrations in mouse bone marrow by multiple treatments of methotrexate.

Methotrexate (MTX), an inhibitor of dihydrofolate reductase (DHFR), slightly induced micronuclei and this induction of micronuclei was enhanced by multiple treatments with the drug (Yamamoto et al., 1981; Hayashi et al., 1984; CSGMT/JEM.MMS, 1990). More micronuclei and chromosomal aberrations in mouse bone marrow cells were induced by multiple than by single treatment. The MTX level in mouse plasma and bone marrow showed little (or no) differences between single and quadruple treatments several hours after the injection(s). On the other hand, the DHFR activity in bone marrow cells 3 h after one and four injections was decreased to approximately 38 and 0%, respectively, of that in non-treated mice. Furthermore, the intracellular MTX level in the bone marrow cells (but not in total bone marrow) after four injections was about 10-fold higher than that after one injection. The amount of MTX bound to protein 3 h after four injections, as assayed by gel filtration (Sephadex G-25), was approximately 8-fold greater than after one injection. Therefore, the multiple-dose effects of MTX on the induction of micronuclei and chromosomal aberrations may be explained by the intracellular accumulation of MTX resulting in an enhancement of enzyme inhibition.

Clonidine attenuates the carbachol-induced contractile and phosphatidylinositol responses of rat trachea.

Although clonidine is known to affect vascular smooth muscle, its effects on airway smooth muscle are not fully understood. This study was designed to examine the effects of clonidine on carbachol-induced contractile and phosphatidylinositol responses of rat trachea. Clonidine, at a dose of 100 microM or greater, attenuated carbachol-induced contraction and the accumulation of carbachol-induced inositol monophosphate (IP1). Clonidine also attenuated the accumulation of aluminium fluoride-induced IP1. The concentration-effect relationship of IP1 accumulation was similar to that of carbachol-induced contraction; r = 0.797, P < 0.001. These results suggest that clonidine attenuates contractile responses, at least in part, through the inhibition of phospholipase C (coupled with G-proteins) in phosphatidylinositol responses.

Effect of glycated low density lipoprotein on smooth muscle cell proliferation.

BACKGROUND: We investigated the effect of glycated low density lipoprotein (LDL) on smooth muscle cell proliferation. METHODS: Blood was drawn from 6 healthy subjects after overnight fasting. Native LDL was obtained by separating LDL from the samples with sequential ultracentrifugation. Glycated LDL was prepared by glycating the native LDL in vitro. Native and glycated LDL were added to a medium containing cultured porcine coronary artery smooth muscle cells, and the change in cell proliferation was examined after 24, 48, 72, and 96 hs. The cells were counted using a cell counting kit (Dojin Chemical Co., Ltd.). RESULTS: There was no significant difference in the cell count between the control group, in which only PBS was added, and the native LDL group. However, cell proliferation was appreciably higher in the glycated LDL group than in the native LDL group. The mean total cell count at 24, 48, 72 and 96 hs was significantly higher (p<0.01) in the glycated LDL group (median: 0.843; range: 0.576-1.060) than in the native LDL group (median: 0.541; range: 0.282-0.683). CONCLUSIONS: These findings suggest that glycated LDL induces significantly greater acceleration of smooth muscle cell proliferation than does native LDL. Therefore, the acceleration of smooth muscle cell proliferation requires modification of LDL.

Importance of glycation in the acceleration of low density lipoprotein (LDL) uptake into macrophages in patients with diabetes mellitus.

BACKGROUND: Two studies were conducted to determine the importance of glycation in the acceleration of low density lipoprotein (LDL) uptake by macrophages in patients with diabetes mellitus. METHODS: Healthy individuals (n=6) and non-insulin-dependent diabetic patients (n=6) were studied. LDL was separated by sequential ultracentrifugation. Macrophages were collected from the abdominal cavity of ICR-mice and incubated in a medium containing [14C] oleate. In Study 1, LDL from diabetic patients (DM-LDL) and control LDL were then incubated with this medium. The uptake of DM-LDL by macrophages was compared with that of control LDL by measuring the [14C] content of the synthesized cholesteryl ester. In Study 2, glycated LDL was prepared by glycating LDL from 6 healthy individuals in vitro. The uptake of native LDL by macrophages was compared with that of glycated LDL using the same method as in Study 1. RESULTS: In Study 1, the uptake of DM-LDL (median: 1,405; range: 985-2269 dpm) was significantly higher than that of control LDL (median: 1,095; range: 990-1104 dpm, p<0.05). In Study 2, the uptake of glycated LDL (median: 1,556; range: 889-2837 dpm) was significantly higher than that of native LDL (median: 1,176; range: 789-2098 dpm, p<0.05). CONCLUSIONS: The results indicate that the greater uptake of DM-LDL than that of control LDL may be attributed to glycation of LDL caused by hyperglycemia in diabetic patients. Glycation of LDL by hyperglycemia may be one cause of the accelerated atherogenesis in diabetic patients.

Gross and microscopic characteristics of liver lesions induced by direct injection of pentobarbital sodium into rats.

The hepatotoxic effects of anesthetics brought about by their faulty intraperitoneal application was investigated. Using a syringe with a 26G needle, we injected 0.05 ml/rat of a 50 mg/ml solution of pentobarbital sodium directly into the livers of Sprague-Dawley rats. The animals were killed at 15, 30, or 45 minutes after injection. Massive hemorrhagic necrosis of the liver was seen in all animals injected, while focal necrosis accompanied by inflammatory cell infiltration was observed in the rats killed at 30 and 45 minutes after injection. The histological characteristics of these liver lesions were composed of three types, namely, massive hemorrhagic necrosis, focal cell infiltration separate from the necrosis, and focal necrosis with inflammatory cell infiltration. The infiltrates were composed of both neutrophils and lymphocytes. The characteristic liver lesions closely resembled the hepatic lesions produced by captopril (Helliwel et al., 1985), cyclopiazonic acid (Morrissey et al., 1985), as well as spontaneous liver lesions. The study of serum transaminase levels showed that the elevation of both SGPT and SGOT activities was correlated with the time after injection. Also, a significant increase in the total bilirubin level was noted in all animals treated.

No effect of voluntary exercise on ovarian follicle in rats.

The present study was to clarify the relationship between voluntary exercise and follicular growth or ovulation. Rats kept for 4 weeks in a rotating drum with free access to the wheel, food and water ran 2-12 km per day. The number of ova shed after superovulation treatments and the number of non-atretic follicles were not influenced by voluntary exercise. These experiments demonstrate that spontaneous voluntary exercise does not affect either the number of ova shed or the number of non-atretic follicles in superovulating rats or control rats.

Preventive effects of dehydroepiandrosterone acetate on the fatty liver induced by orotic acid in male rats.

Preventive effects of dehydroepiandrosteone acetate (DHEA-A) and clofibrate (positive control substance) on the fatty liver induced by orotic acid (OA) were examined on the male Sprague-Dawley rats fed a high sucrose based diet containing 1% OA and this diet further mixed with 0.5% DHEA-A or 0.5% clofibrate for 2 weeks. Numerous lipid droplets were observed in the hepatocytes of the rats treated with OA alone, but not in those treated with DHEA-A or clofibrate. In comparison to the group with OA alone, the DHEA-A or clofibrate treated rats showed a larger relative liver weight (to body weight) which was accompanied by increased peroxisomes in the hepatocytes. These results indicate that DHEA-A, as well as clofibrate, may prevent OA-induced fatty liver.