Percutaneous penetration of indomethacin

Summary ¹⁴C-Indomethacin (ID) was applied to the skin of guinea-pigs as an ointment. After several applications, the concentration of ID in the skin and muscle under the applied site reached a constant level. The concentration of ID in the muscle as well as the skin may be enough to exert an anti-inflammatory effect.     

基于决策树的超市客户数据挖掘与仿真

FoodMart超市市场部想提高客户满意度和客户保有率，于是计划对会员卡方案重新定义，以便更好地为客户提供服务并且使提供的服务能够更加密切地满足客户的期望。本文基于对FoodMart超市客户数据的分析，适当选取某些客户类型特征作为决策属性，并利用ID3算法从FoodMart超市客户数据中挖掘客户分类规则。并利用java语言编程实现了ID3算法。仿真的结果不仅为FoodMart超市会员卡重新定义制定最佳的指导策略，而且在理论研究和工程实践中都具有重要的意义。     

Cardiomyocyte growth and sarcomerogenesis at the intercalated disc

Cardiomyocytes grow during heart maturation or disease-related cardiac remodeling. We present evidence that the intercalated disc (ID) is integral to both longitudinal and lateral growth: increases in width are accommodated by lateral extension of the plicate tread regions and increases in length by sarcomere insertion within the ID. At the margin between myofibril and the folded membrane of the ID lies a transitional junction through which the thin filaments from the last sarcomere run to the ID membrane and it has been suggested that this junction acts as a proto Z-disc for sarcomere addition. In support of this hypothesis, we have investigated the ultrastructure of the ID in mouse hearts from control and dilated cardiomyopathy (DCM) models, the MLP-null and a cardiac-specific β-catenin mutant, cΔex3, as well as in human left ventricle from normal and DCM samples. We find that the ID amplitude can vary tenfold from 0.2 μm up to a maximum of ~2 μm allowing gradual expansion during heart growth. At the greatest amplitude, equivalent to a sarcomere length, A-bands and thick filaments are found within the ID membrane loops together with a Z-disc, which develops at the transitional junction position. Here, also, the tops of the membrane folds, which are rich in αII spectrin, become enlarged and associated with junctional sarcoplasmic reticulum. Systematically larger ID amplitudes are found in DCM samples. Other morphological differences between mouse DCM and normal hearts suggest that sarcomere inclusion is compromised in the diseased hearts.     

The CD40/CD154 receptor/ligand dyadRID="†"ID="†" Review

Until recently, the expression and primary function of the cell surface receptor CD40 and its ligand CD154 were considered restricted to B and T lymphocytes, and their interactions required for the thymus-dependent humoral response. However, current work from several groups challenges this view of the CD40/CD154 dyad as a mere mediator of lymphocyte communication. A variety of non-lymphocytic cell types express both receptor and ligand, including hematopoetic and non-hematopoetic cells, such as monocytes, basophils, eosinophils, dendritic cells, fibroblasts, smooth muscle, and endothelial cells. Accordingly, ligation of CD40 mediates a broad variety of immune and inflammatory responses, such as the expression of adhesion molecules, cytokines, matrix-degrading enzymes, prothrombotic activities, and apoptotic mediators. Consequently, CD40 signaling has been associated with pathogenic processes of chronic inflammatory diseases, such as autoimmune diseases, neurodegenerative disorders, graft-versus-host disease, cancer, and atherosclerosis. This review focuses on the synthesis and structure of CD40 and outlines CD154/CD40 signaling pathways, and emphasizes the previously unexpected importance of the CD40/CD154 receptor/ligand dyad in a spectrum of immunoregulatory processes and prevalent human diseases. Received 10 January 2000; revised 16 June 2000; accepted 5 July 2000 RID="†" ID="†" Review RID="*" ID="*" Corresponding author.     

Membrane-traversing mechanism of thyroid hormone transport by monocarboxylate transporter 8

Monocarboxylate transporter 8 (MCT8) mediates thyroid hormone (TH) transport across the plasma membrane in many cell types. In order to better understand its mechanism, we have generated three new MCT8 homology models based on sugar transporters XylE in the intracellular opened (PDB ID: 4aj4) and the extracellular partly occluded (PDB ID: 4gby) conformations as well as FucP (PDB ID: 3o7q) and GLUT3 (PDB ID: 4zwc) in the fully extracellular opened conformation. T₃-docking studies from both sides revealed interactions with His192, His415, Arg445 and Asp498 as previously identified. Selected mutations revealed further transport-sensitive positions mainly at the discontinuous transmembrane helices TMH7 and 10. Lys418 is potentially involved in neutralising the charge of the TH substrate because it can be replaced by charged, but not by uncharged, amino acids. The side chain of Thr503 was hypothesised to stabilise a helix break at TMH10 that undergoes a prominent local shift during the transport cycle. A T503V mutation accordingly affected transport. The aromatic Tyr419, the polar Ser313 and Ser314 as well as the charged Glu422 and Glu423 lining the transport channel have been studied. Based on related sugar transporters, we suggest an alternating access mechanism for MCT8 involving a series of amino acid positions previously and newly identified as critical for transport.     

Physiologische Untersuchungen an der innervierten glatten Muskulatur der Vogelfedern (Mm. pennarum)

Summary The tension development of the smooth feather muscles of the pigeon was measured (a) on the wing in situ (b) on an isolated innervated skin preparation and (c) on an isolated muscle preparation. The contraction produced by nerve stimulation is biphasic. The second phase can be blocked by -receptor blocking agents. The mechanism of the first phase is unknown. The preparation seems very suitable for the investigation of neuromuscular transmission in smooth muscle.     

The response of Ca-mediated action potentials and contractile activity in mammalian ventricular myocardium towards alkalosis.

Alkalosis (pH 7.8) produced by reduction of CO2 concentration augmented both upstroke velocity of Ca action potentials and isometric contractile force of mammalian heart muscle. If the increase of pH to 7.8 was achieved by a raise of HCO3 concentration (with simultaneous reduction of CO2 concentration), the positive inotropic response was not accompanied by an augmented Ca current. Obviously, the well-known positive inotropic effect of alkalosis does not only depend upon the enhancement of transmembrane Ca influx during excitation, but can be mediated alone by affecting intracellular Ca movements as well.     

Statins: the new aspirin?

3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors, or statins, have been described as the principal and the most effective class of drug to reduce serum cholesterol levels. Statin therapies have been shown to reduce cardiovascular events, including myocardial infarction, stroke, and death, significantly, by altering vascular atherosclerosis development in patients with or without coronary artery disease symptoms. Extensive use of statins has led to the increase of some undesirable effects that are heavily counterbalanced by the benefits. Indeed, pleiotropic effects extend far beyond cholesterol reduction and involve non-lipid-related mechanisms that modify endothelial functions, immunoinflammatory responses, smooth muscle cell activation, proliferation and migration, atherosclerotic plaque stability, and thrombus formation. In this review, we describe in detail the targets and mechanisms of action of statins. Received 6 June 2002; received after revision 6 September 2002; accepted 6 September 2002 RID="*" ID="*"Corresponding author.     

The effect of age on cardiac output and its distribution in the rat.

Cardiac output distribution in the rat was found to be affected by age. Cardiac index and blood flow to the liver, kidneys, skin and skeletal muscle were lower in 11-12 month compared to 3-4 month old rats.     

Developmental forms of human skeletal muscle AMP-deaminase

Chromatography on phosphocellulose revealed the existence of two well-separable forms of skeletal muscle AMP-deaminase in the tissue extracts of 11- and 16-week-old human fetuses. One of these forms elutes from the column at the same salt concentration as the muscle isozyme found in the skeletal muscle extract from adult man, and seems to have similar kinetic properties. The second form, which was found only in vestigial amounts in adult human tissue extract, represents different kinetic properties and seems to be a form characteristic for the fetal period of ontogenesis.     

The response of Ca-mediated action potentials and contractile activity in mammalian ventricular myocardium towards alkalosis

Summary Alkalosis (pH 7.8) produced by reduction of CO₂ concentration augmented both upstroke velocity of Ca action potentials and isometric contractile force of mammalian heart muscle. If the increase of pH to 7.8 was achieved by a raise of HCO₃ concentration (with simultaneous reduction of CO₂ concentration), the positive inotropic response was not accompanied by an augmented Ca current. Obviously, the well-known positive inotropic effect of alkalosis does not only depend upon the enhancement of transmembrane Ca influx during excitation, but can be mediated alone by affecting intracellular Ca movements as well.     

Influence of flupirtine, a novel nonopioid analgesic agent on somatosensory evoked potentials in rats.

The effect of flupirtine, a novel nonopioid analgesic, on somatosensory evoked potentials (SEP) was investigated in anesthetized rats. Primary somatosensory potentials were evoked in the cerebral cortex by stimulation of the skin of the whiskery part of the face. Flupirtine injected i.p. dose-dependently prolonged the latency and reduced the amplitude of SEP with ID50-values of 5.4 mg/kg (2.6-9.3 mg/kg) and 7.9 mg/kg (3.9-13.8 mg/kg), respectively. This effect of flupirtine (10 mg/kg, i.p.) on the latency and the amplitude of SEP, did not change when naloxone (1 mg/kg, i.p.) was given before flupirtine. The results indicate that the analgesic flupirtine decreases the primary somatosensory evoked potential by diminishing the excitability of cortical neurons. Opioid mechanisms are not involved.     

ERKs are the point of divergence of PKA and PKC activation by PTHrP in human skin fibroblasts

Parathyroid hormone-related peptide (PTHrP) receptors, coupled to trimeric G proteins, operate in most target cells through at least three different transduction routes: Gαs-mediated stimulation of adenylylcyclase (AC), Gαq-mediated activation of phospholipase Cβ (PLC) and mitogen-activated protein kinase (MAPK) activation. In this study we investigated the relative role of different pathways in human skin fibroblast prolifera-tion. Using chemical inhibitors and activators of signal transduction, we demonstrated that: (i) AC/cAMP and PLC/1,4,5 inositol triphosphate/diacylglycerol second-messenger systems are simultaneously activated following PTHrP binding to its receptors; (ii) the mitogenic response to PTHrP derives from a balance between two counteracting pathways – an activating route mediated by protein kinase C (PKC) and an inhibitory route mediated by protein kinase A (PKA); (iii) PTHrP mitogenic effects are largely dependent on MAPKs, whose activity can be modulate d by both PKA and PKC. Our results indicate that MAPKs are common targets of both transduction routes and, at the same time, their point of divergence in mediating PTHrP dual and opposite mitogenic effects. Received 2 August 2002; received after revision 10 September 2002; accepted 18 October 2002 RID="*" ID="*"Corresponding author.     

Presence of NAD pyrophosphorylase in skeletal muscle in dystrophic mice

Summary NAD pyrophosphorylase (ATP:NMN adenylyltransferase) activity has been measured in the skeletal muscle of dystrophic mice. The amount of this enzyme in the dystrophic mice, as determined by three different methods, was about one half of that in the controls. In addition, the concentration of ATP was too low to be detected in crude extracts of dystrophic mouse skeletal muscle, which were prepared using Tris buffer alone or Tris buffer containing either 3 M KCl, or 1 mM PMSF.     

Presence of NAD pyrophosphorylase in skeletal muscle in dystrophic mice

NAD pyrophosphorylase (ATP:NMN adenylyltransferase) activity has been measured in the skeletal muscle of dystrophic mice. The amount of this enzyme in the dystrophic mice, as determined by three different methods, was about one half of that in the controls. In addition, the concentration of ATP was too low to be detected in crude extracts of dystrophic mouse skeletal muscle, which were prepared using Tris buffer alone or Tris buffer containing either 3 M KCl, or 1 mM PMSF.     

A comparison between skin-photosensitizing (334 nm) activities of 8-methoxypsoralen and angelicin

Summary 8-Methoxypsoralen and angelicin, locally applied to the skin of the rabbit, photosensitized erythema under UV irradiation to an approximately equal extent. Incident UV irradiation was restricted mainly to 334 nm. This indicates that furocoumarin-DNA cross-links are not important in erythema induction.Acknowledgment. We are grateful to Professor G. Rodighiero for his kindness in supplying furocoumarins.     

Non-uniformity of regional vasomotor activity indicating the existence of 2 different systems in the sympathetic cardiovascular outflow

Summary In rabbits, 2 populations of sympathetic postganlionic fibres innervating the skin, heart, muscle and kidney could be classified by their different spike heights and their different susceptibility to noradrenaline and angiotensin amide. The ability of the 2 populations to respond to physiological stimuli in a highly differentiated manner leads to the assumption that 2 different systems in the cardiovascular sympathetic outflow exist.     

New endo-beta-1,4-glucanases from the parabasalian symbionts,Pseudotrichonympha grassii and Holomastigotoides mirabile of Coptotermes termites

An endo-β-1,4-glucanase (EG) was purified from the hindgut of an Australian mound-building termite, Coptotermes lacteus. The hindgut extract had a peak separate from those for extracts obtained from the salivary glands and the midgut based on sephacryl S-200 gel chromatography, and also demonstrated an origin different from the endogenous EGs of the termite itself. The recovery was further purified by SDS-PAGE, and its N-terminal amino acid sequence analyzed. This showed high homology to EGs from glycoside hydrolase family (GHF) 7. PCR-based cloning methods were applied to the hindgut contents of C. lacteus and individual protozoan symbionts from C. formosanus. cDNAs encoding putative EGs homologous to GHF7 members were then identified. The functionality of one of the putative proteins was confirmed by its expression in Escherichia coli. Received 18 September 2002; accepted 20 September 2002 RID="*" ID="*"Corresponding author.     

Calcium transients in a molluscan smooth muscle

Summary The changes in myoplasmic calcium concentration during contraction were recorded in the anterior byssal retractor muscle ofMytilus edulis using murexide as calcium indicator, and were found to be qualitatively similar to those in striated muscles except for their slow time course.     

Energetics and regulation of crossbridge states in mammalian smooth muscle

Conclusion On the basis of measurements of the high energy phosphate usage associated with different mechanical states, as well as the degree of myosin light chain phosphorylation and mechanical properties, information has been gained concerning the existence and regulation of different crossbridge states in smooth muscle. Although incomplete, a general operational scheme is shown in figure 5. At very low intracellular calcium concentrations, actin and myosin are dissociated, as shown by a loss of resistance to stretch in resting muscles. At somewhat higher intracellular calcium concentrations in atonic, resting muscles, crossbridges can attach and be manifest mechanically as an increased resistance to stretch without ATP-driven crossbridge cycling and active force production. When the muscle is activated, intracellular calcium increases further, the light chains of myosin are phosphorylated through the calcium-calmodulin activation of myosin light chain kinase, actin-activated myosin ATPase activity increases and crossbridges cycle. Calcium also appears to modulate the ATPase activity and the rate of cycling of the phosphorylated crossbridge. The crossbridge cycling rate is highest during force development and slows with time as maximum isometric force is maintained reflecting a change in the rate at which phosphorylated crossbridges cycle. This may result from a decrease in the intracellular free calcium concentration with continued stimulation. During relaxation, the intracellular calcium concentration decreases, there is net dephosphorylation of the myosin light chains, the rate at which phosphorylated crossbridges cycle slows further with a gradual return to the attached, but non-cycling state or the detached state.