Interaction between sodium ascorbate and dopamine

The interaction between sodium ascorbate and dopamine was investigated by three different parameters: radical intensity, prooxidant action, and cytotoxicity induction. Sodium ascorbate and dopamine produced the doublet and quartet ESR signals under alkaline conditions (pH 8.0-9.5), respectively. Addition of increasing concentrations of sodium ascorbate completely scavenged the dopamine radical and replaced the latter with its own radical. Similarly, dopamine slightly, but significantly reduced the radical intensity of sodium ascorbate. These two compounds stimulated the methionine oxidation and hydrogen peroxide generation in culture medium, but in combination, their stimulation activities were weakened. Both of these two compounds dose-dependently reduced the viable cell number of human oral squamous carcinoma HSC-4 cells, and their cytotoxic activity was significantly reduced by catalase. When these two compounds were mixed together before adding to HSC-4 cells, both of their cytotoxic activities were diminished. The present study demonstrates the interaction between sodium ascorbate and dopamine, which might modify their biological activities and generation of nerve disorders such as Parkinson's disease.     

Controlled release of drugs from hydrogel matrices

A series of polymers with wide ranges of water absorptivity were prepared and utilized as matrices for the controlled release of drugs. The drugs were introduced into the matrices by use of an appropriate organic solvent. Release rates of erythromycin and erythromycin estolate from hydrogel were analyzed kinetically and found to conform to Higuchi's equation, that is, M_t = A(2DtC_sC₀)^1/2, where M_t is the accumulated amount of released drug at time t, A is the surface area, D is the diffusion coefficient, C_s is the solubility of drug in the hydrogel matrix, and C_o is the initial drug content of the preparation in the swollen state. The relationship between the water content of hydrogel and the diffusion coefficient of erythromycin in hydrogel is expressed by the equation D = 3.03 × 10^?10 W^3.03 (cm²/sec), where W is the water content (%). The release rate of drug can be controlled quantitatively by adjustment of the water content of the hydrogel matrix. A guide to the design for the preparation is suggested.     

Thymus transplantation, a critical factor for correction of autoimmune disease in aging MRL/+mice

MRL/MP-+/+ (MRL/+) mice develop pancreatitis and sialoadenitis after they reach 7 months of age. Conventional bone marrow transplantation has been found to be ineffective in the treatment of these forms of apparent autoimmune disease. Old MRL/+ mice show a dramatic thymic involution with age. Hematolymphoid reconstitution is incomplete when fetal liver cells (as a source of hemopoietic stem cells) plus fetal bone (FB; which is used to recruit stromal cells) are transplanted from immunologically normal C57BL/6 donor mice to MRL/+ female recipients. Embryonic thymus from allogeneic C57BL/6 donors was therefore engrafted along with either bone marrow or fetal hematopoietic cells (FHCs) plus fragments of adult or fetal bone. More than seventy percent of old MRL/+ mice (> 7 months) that had been given a fetal thymus (FT) transplant plus either bone marrow or FHCs and also bone fragments survived more than 100 days after treatment. The mice that received FHCs, FB, plus FT from allogeneic donors developed normal T cell and B cell functions. Serum amylase levels decreased in these mice whereas they increased in the mice that received FHCs and FB but not FT. The pancreatitis and sialoadenitis already present at the time of transplantations were fully corrected according to histological analysis by transplants of allogeneic FHCs, FB and FT in the MRL/+ mice. These findings are taken as an experimental indication that perhaps stem cell transplants along with FT grafts might represent a useful strategy for treatment of autoimmune diseases in aged humans.     

Psychiatric evaluation of physical rehabilitation patients

We conducted a study to demonstrate the frequency and types of psychiatric/psychological symptoms. A Structured Interview according to the DSM-III-R was conducted which demonstrated that 46 (41.4%) of 111 rehabilitation inpatients met the criteria for some forms of psychiatric disorders: 34 patients for major depression, 10 for adjustment disorder with anxious mood, and 2 for posttraumatic stress disorder. The remaining 65 patients (58.6%) showed normal reactions to their diseases. Average length of hospital stay for patients with major depression was significantly longer than those with no or the other types of psychiatric disease. They were also tested with Zung's Self-Rating Anxiety Scale (SAS), Zung's Self-Rating Depression Scale (SDS), and Profile of Mood States (POMS). Three psychological tests were useful in detecting depression or adjustment disorder among rehabilitation patients; however, these tests are not always specific to the type of psychiatric disorders. Patients with higher scores in those three tests should be referred to a psychiatric consultant for detailed examinations and proper treatments, if necessary.     

Low-loss polarisation-maintaining optical fibre with low crosstalk

A low-loss polarisation-maintaining optical fibre with low crosstalk is presented. The minimum transmission loss is 0.35 dB/km at 1.54 ?m and crosstalk is ?32 dB at 1.56 ?m in a 1 km length. The relative refractive index difference between core and cladding is 0.3%, and the modal birefringence is 2.8 × 10?4.     

p85alpha gene generates three isoforms of regulatory subunit for phosphatidylinositol 3-kinase (PI 3-Kinase), p50alpha, p55alpha, and p85alpha, with different PI 3-kinase activity elevating responses to insulin

Phosphatidylinositol 3-kinase (PI 3-kinase) is stimulated by association with a variety of tyrosine kinase receptors and intracellular tyrosine-phosphorylated substrates. We isolated a cDNA that encodes a 50-kDa regulatory subunit of PI 3-kinase with an expression cloning method using 32P-labeled insulin receptor substrate-1 (IRS-1). This 50-kDa protein contains two SH2 domains and an inter-SH2 domain of p85alpha, but the SH3 and bcr homology domains of p85alpha were replaced by a unique 6-amino acid sequence. Thus, this protein appears to be generated by alternative splicing of the p85alpha gene product. We suggest that this protein be called p50alpha. Northern blotting using a specific DNA probe corresponding to p50alpha revealed 6.0- and 2.8-kb bands in hepatic, brain, and renal tissues. The expression of p50alpha protein and its associated PI 3-kinase were detected in lysates prepared from the liver, brain, and muscle using a specific antibody against p50alpha. Taken together, these observations indicate that the p85alpha gene actually generates three protein products of 85, 55, and 50 kDa. The distributions of the three proteins (p85alpha, p55alpha, and p50alpha), in various rat tissues and also in various brain compartments, were found to be different. Interestingly, p50alpha forms a heterodimer with p110 that can as well as cannot be labeled with wortmannin, whereas p85alpha and p55alpha associate only with p110 that can be wortmannin-labeled. Furthermore, p50alpha exhibits a markedly higher capacity for activation of associated PI 3-kinase via insulin stimulation and has a higher affinity for tyrosine-phosphorylated IRS-1 than the other isoforms. Considering the high level of p50alpha expression in the liver and its marked responsiveness to insulin, p50alpha appears to play an important role in the activation of hepatic PI 3-kinase. Each of the three alpha isoforms has a different function and may have specific roles in various tissues.     

Inhibitory effects by a submandibular gland extract on luteinizing hormone-stimulated testosterone production by testicular cells

In order to develop an animal model for in vivo testing of the displacing action of various drugs and for study of the bilirubin deposition in the brain, some molecular properties of the serum albumin from different species i.e. pig, cat, human, dog, sheep, guinea pig and rat were investigated. These albumins were found to have differences in molecular weight, Stokes radius and electrophoretic mobility. They also showed different bilirubin binding characteristics when studied by spectroscopy and fluorescence quenching. It is therefore, necessary to consider the species differences when results of animal experimentation are used as a basis for the investigation of human kernicterus.     

Dispersion of pure GeO2 glass core and f-doped GeO2 glass cladding single-mode optical fibre

The letter investigates the dispersion of GeO2 glass core and F-doped GeO2 glass cladding single-mode optical fibre. It is estimated that the total dispersion goes to zero at about ? = 1.77 ?m. The material dispersions of these glasses are also measured. Material dispersion of GeO2 glass, which contains fluorine of 0.41 wt%, vanished at ? = 1.722?m. This occurs at ? = 1.734 ?m for pure GeO2 glass.     

Electrochemically prepared poly(3-methylthienylene) films doped with iodine

Electrochemically prepared poly(3-methylthienylene) films doped with iodine have been investigated and the relationship between their conductivity and iodine content was studied. The conductivity of the films with various iodine contents was obtained in accordance with an Arrhenius equation with an activation energy equal to 0.17 to 0.033 eV. The highest conductivity was 5 S cm^?1. The activation energy, which is dependent on the iodine content, shows discontinuous change, as is the case with polyacetylene doped with iodine. The relationship between conductivity and structure of the poly(3-methylthienylene) films will be discussed.