Intraperitoneal administration of choline increases serum glucose in rat: involvement of the sympathoadrenal system.

Intraperitoneal injection of choline (40, 80 or 120 mg/kg) produced a dose-dependent increase in serum glucose and choline levels in rats. The increases in serum glucose and choline were associated with an increase of serum insulin as well as plasma levels of epinephrine and norepinephrine. The increases in serum glucose and plasma catecholamine concentrations induced by choline (120 mg/kg) were blocked by pretreatment with the ganglionic nicotinic receptor antagonist hexamethonium (15 mg/kg), but were not affected by pretreatment with atropine (5 mg/kg). The choline-induced rise in serum insulin was blocked by pretreatment with atropine and with hexamethonium each. The increase in serum glucose evoked by choline (120 mg/kg) was blocked by alpha-adrenoceptor blockade and bilateral adrenalectomy each. Blockade of beta-adrenoceptor by propranolol or chemical sympathectomy by 6-hydroxydopamine failed to alter the hyperglycemic response to choline. These results show that choline, a precursor of the neurotransmitter acetylcholine, increases serum glucose and insulin levels. The effect of choline on serum insulin is mediated by both muscarinic and nicotinic acetylcholine receptors, whereas the effect of choline on serum glucose is mediated solely by nicotinic receptors. The stimulation of adrenal medullary catecholamine release and subsequent activation of alpha-adrenoceptors apparently mediates the hyperglycemic effect of choline.

Visible-light photocatalysis in nitrogen-doped titanium oxides.

To use solar irradiation or interior lighting efficiently, we sought a photocatalyst with high reactivity under visible light. Films and powders of TiO(2-x)N(x) have revealed an improvement over titanium dioxide (TiO2) under visible light (wavelength < 500 nanometers) in optical absorption and photocatalytic activity such as photodegradations of methylene blue and gaseous acetaldehyde and hydrophilicity of the film surface. Nitrogen doped into substitutional sites of TiO2 has proven to be indispensable for band-gap narrowing and photocatalytic activity, as assessed by first-principles calculations and x-ray photoemission spectroscopy.

Analysis of dark spots growing in organic EL devices by time-of-flight secondary ion mass spectrometry.

Chemical structural analysis of tape-stripped surfaces at dark spots growing in organic electroluminescent (EL) devices during exposure to the atmosphere was done by time-of-flight secondary ion mass spectrometry (OF-SIMS). The EL devices consist of indium-tin-oxide, triphenylamine-tetramer, tris(8-hydroxyquinoline)aluminum (Alq3), and a Mg-Ag cathode deposited in order under vacuum on a glass substrate. It was found that the interface between the Alq3 layer and the Mg-Ag cathode was exposed as a result of tape-stripping, where a large number of dark spots were observed on both sides. Secondary ion images of O-, Mg+, and Alq2+ were observed from the dark spots on the cathode side. On the other hand, Mg+ and O- images with a nucleus in the center were observed from the Alq3 side. It is concluded from the results that the constituent element Mg of the cathode was oxidized at the interface adjacent to the Alq3 layer during exposure to the atmosphere, forming a dark spot with a nucleus in the center. Finally, it was confirmed that the TOF-SIMS analysis of the tape-stripped surface is useful for the analysis of the mechanism of dark spot formation.

New method for divesting cobalt-chromium alloy castings: sandblasting with a mixed abrasive powder.

STATEMENT OF PROBLEM: Because the conventional divesting method for cobalt-chromium (Co-Cr) alloys is laborious, a more convenient method is desirable. PURPOSE: This study compared sandblasting with a mixed powder composed of aluminum oxide and glass beads to sandblasting with single powders (carborundum, aluminum oxide, and glass beads) when a Co-Cr casting was removed from the investment mold. MATERIAL AND METHODS: Rectangular plates with the 2 surfaces simulating the inner and outer surfaces of a removable partial denture framework were fabricated with Co-Cr alloys. Four kinds of sandblasting powders were used to remove the remnants of investment molds. Total time (seconds) required for each procedure was measured, as was the surface roughness (Ra) of each specimen after sandblasting. SEM was used to analyze the powders themselves and the sandblasted specimen surfaces. RESULTS: Glass beads alone and the mixed powder of aluminum oxide and glass beads generated a smoother surface compared with aluminum oxide and carborundum powders. The use of the mixed powder significantly reduced the time of the sandblasting procedure. SEM revealed that glass beads generated fewer scars, followed by the mixed powder and then aluminum oxide. The surface sandblasted by carborundum powder was always the roughest. CONCLUSION: Sandblasting Co-Cr castings with the mixed powder effectively decreased treatment time and resulted in smooth, clinically acceptable casting surfaces.

Apolipoprotein E Genotyping in Turkish Myocardial Infarction Survivors and Healthy Controls.

The apolipoprotein (Apo) E gene is known to be polymorphic. Three common alleles determine six phenotypes which can easily be detected by restriction fragment length polymorphism. We performed apo E genotyping in myocardial infarction survivors and healthy controls for the first time in the Turkish population. DNA was amplified by polymerase chain reaction (PCR) and the PCR product was digested with restriction enzymes HhaI to detect apo E2, E3, E4 and with TaqI to detect apo E1. Relative allele frequency for the patient group was found to be 0.91 for E3, 0.07 for E2, 0.02 for E4 and for the control group 0.875 for E3, 0.067 for E2, 0.058 for E4. Copyright 1995 S. Karger AG, Basel

Recent progress of optical thin films in the automobile industry.

There are increasing demands for the application of optical thin films to transparent substrates such as glass and plastics for windows in automobiles with the view of adding fascinating optical properties to them. These properties include surface hardening of plastics, infrared reflection, ultraviolet absorption, polarization and birefringence, and hydrophobicity. Recent examples of applications of sophisticated thin-film processes of plasma treatment and physical vapor deposition are reviewed. The novelty of the functions provided by physical vapor deposition films together with their durability for practical usage are emphasized as areas in which the thin-film process has a significant impact. Characterization of the modified surface and interface is also included to demonstrate recent advances in surface chemistry. Finally, future challenges for optical modification of transparent substrates in the automobile industry are also discussed.

Subcellular localization of radioactively labelled defibrotide in cultured endothelial cells.

Defibrotide is a new antithrombotic and fibrinolytic drug which is obtained by controlled depolymerization of mammalian DNA. In various models of arterial and venous thrombosis, it has been shown that it induces tissue plasminogen activator [tPA] and prostacyclin [PGI2] release from the vessel wall. We have previously shown the presence of specific binding sites with a Kd of 4.2 micrograms/ml for radioactively labelled defibrotide. The present study was undertaken to identify the location of the binding site. Confluent cultures of endothelial cells from human umbilical vein were incubated with media containing 3H-acetyl-defibrotide for various intervals of time. Cells were then washed and harvested nonenzymatically. Subcellular location of 3H-defibrotide was investigated by fractionating cells on discontinuous sucrose gradient and measuring the distribution of radioactivity. 5'-nucleotidase enzyme activity was also measured to ensure the location of membrane fraction. Our results suggest that the major location of 3H-defibrotide in endothelial cells is the plasma membrane. On the other hand, nuclei also contain a considerable amount of the drug which suggests a mechanism where binding to a membrane protein is followed by internalization.

Effect of diltiazem on renal function in patients with liver cirrhosis.

Calcium channel blockers have strong vasodilator, natriuretic and diuretic actions in normal and hypertensive subjects. The aim of this study was to evaluate the effect of diltiazem on renal function, renin-angiotensin-aldosterone axis (RAA) and atrial natriuretic factor (ANF) in patients with liver cirrhosis. Seven patients (3 females and 4 males) with a mean age of 56.3 +/- 11.1 years (36-68) entered the trial. All of the patients had HBV (6 cases) or HCV (1 case) related Child A (3 cases) or Child B (4 cases) liver cirrhosis proven by liver biopsy. Patients were given placebo for 15 days followed by p.o. diltiazem 30 mg t.i.d. for 15 days. Urinary volume, natriuresis, creatinine clearance, plasma renin activity (PRA), ANF and aldosterone (ALD) levels were determined after the washout period and during the first and second weeks of drug treatment. Urinary volume increased by 25-170% in 5 cases but this difference did not reach statistical significance. Slight increases in natriuresis occurred in some cases on the 3rd day of the trial but the overall results were not statistically significant (191.50 +/- 26.85 vs 204.07 +/- 39.83 mmol/l). Diltiazem induced no significant changes in PRA, ALD and ANF levels or creatinine clearance during the first or second weeks of the trial. There was a significant drop in the pulse rate on the first or second weeks of the treatment (p less than 0.01 and p less than 0.05, respectively). No significant changes were noted on mean arterial pressure (MAP).(ABSTRACT TRUNCATED AT 250 WORDS)

Tear lysozyme levels in contact lens wearers.

Tear lysozyme levels in various types of asymptomatic contact lens wearers were compared with those in age- and sex-matched healthy control subjects. We used a radial immunodiffusion technique, and the lysozyme levels were in the normal range in controls and contact lens wearers. A comparison of the tear lysozyme levels of 27 contact lens wearers (mean, 1.05 +/- 0.45 g/L) with 22 control subjects (mean, 0.84 +/- 0.39 g/L) was statistically significant (P less than .05). The mean tear lysozyme levels of rigid (1.12 +/- 0.54 g/L, P less than .05) and high water-content (1.20 +/- 0.43 g/L, P less than .03) contact lens wearers were increased in comparison with the control group. The tear lysozyme difference was significant (P less than .03) between high and low water-content (0.82 +/- 0.20 g/L) contact lens users. Our study revealed that, although most of the contact lens wearers were asymptomatic and there was no pathologic sign of external ocular inflammation, a change in tear lysozymes was observed. Contact lens wear is irritating to the cornea and conjunctiva, and tear lysozyme physiology is disturbed most by high water-content contact lenses.

The effect of contact lens wear on tear immunoglobulins.

We assayed tear immunoglobulins (IgA, IgG, and IgM) by radial immunodiffusion in 24 contact lens wearers and 22 healthy control subjects. IgA level was found to be increased (P less than or equal to 0.02) in rigid contact lens wearers (mean: 0.14 +/- 0.07 g/L) compared to control subjects (mean: 0008 +/- 0.06 g/L). IgA levels of both of PMMA contact lens wearers (mean: 0.14 +/- 0.08 g/L; P less than or equal to 0.05) and rigid gas permeable contact lens wearers (mean: 0.13 +/- 0.07 g/L; P less than or equal to 0.05) were increased in comparison with the control group. No statistically significant differences were found in IgA levels of various types of soft contact lens wearers or in IgG or IgM levels between wearers and controls. The mean duration of lens wear was 6.4 years (range: 1-20 years), and an increase in IgG level was found, related length of lens wear (P less than or equal to 0.03). We believe that the continuous mechanical stimulation of conjunctiva alters the level of tear immunoglobulins, especially the IgA type.

Clinical application of electric resistance welding and soldering methods to removable partial dentures.

The joining procedure for uniting metal structures is very important in the construction of removable partial dentures. However, it has several restricted problems in joining wrought wire clasps to rests or major connectors. For example, the base metal wires made of chromium-cobalt alloy are subject to changes in their mechanical properties caused by heating, and damage to acrylic resin materials (denture base and artificial teeth) occurs in the repair of removable partial dentures by using the torch soldering method. In this paper, in order to resolve these problems, an electric resistance welding machine was applied to attach wrought wire components to a removable partial denture framework. This welding machine was used to attach metal structures temporarily to each other, and to solder the welded joint with hard solder. Consequently, some problems of the conventional torch soldering method were improved by using the electric resistance welding and soldering methods. It was suggested that the clinical application of the electric welding and soldering methods was very useful in the construction of removable partial dentures.

[Removable partial dentures applied by electric welding and soldering methods].

The joining procedure for uniting metal structures is very important in the dental clinic, and various kinds of metal joining methods have been performed for clinical application. The conventional torch soldering method using a blow torch has been generally adopted. However, it has several clinical problems, especially in the construction of removable partial dentures. The base metal wires made of a chromium-cobalt alloy are subject to changes in their mechanical properties caused by heating, when wrought wire clasps are joined to rests or frameworks. In addition to the flexibility of wrought wire clasps, damage to acrylic resin denture bases and acrylic resin teeth occurs in the repair of removable partial dentures. In this paper, the electric resistance welding and soldering methods were applied to attach wrought wire components to a removable partial denture framework to resolve the problems of the torch soldering method. As a result, it is suggested that these electric resistance welding and soldering methods have the following advantages, as compared with the conventional torch soldering method. 1. When using this electric resistance welding method, it is possible to fix metals temporarily to each other more securely and strongly than the conventional temporary fixation methods using sticky wax or acrylic resin. 2. The electric resistance soldering method does not require any heat insulation or a partition as the torch soldering method does, because the soldered area is only heated partially. 3. In the case of soldering electrically wrought wire clasps to metal structures such as rests and connectors, there is no fear of of overheating a wide area of wires.(ABSTRACT TRUNCATED AT 250 WORDS)

Interaction of 3H-defibrotide with cultured human umbilical vein endothelial cells.

Defibrotide is a profibrinolytic and antithrombotic drug which seems to modulate endothelial cell function. In this study, a method for radioactive labeling of the drug and its interaction with cultured endothelial cells is proposed. 3H-Acetic anhydride was used to label defibrotide. Endothelial cells obtained by collagenase treatment of human umbilical cord veins were cultured in 24-welled plastic culture dishes. Binding experiments were carried out by incubating cell cultures with media containing various concentrations of labeled defibrotide. Our results showed that labeled defibrotide has a KL value of 4.2 micrograms/ml for endothelial cells. Although the presence of a specific transporter is possible, the high molecular weight of the fraction used suggests that the interaction is binding to a specific receptor.

The effect of chronic guanfacine administration on high plasma vasopressin levels in essential hypertension.

In the past several years, investigators have given evidence that vasopressin (VP), in addition to its antidiuretic function, may play an important role in cardiovascular regulation through other mechanisms. An increased plasma VP level has been reported in some patients with mild-to-moderate essential hypertension (EH). Additionally, yohimbine, a selective alpha 2-adrenoceptor antagonist, has been shown to increase the plasma VP level and blood pressure (BP) in man. The present study was performed to evaluate the effects of chronically administered guanfacine, a centrally acting alpha 2-adrenoceptor agonist, on high plasma VP levels in patients with mild-to-moderate EH in whom no other causes responsible for elevated plasma VP levels were present. The relations among VP, BP and renin-angiotensin-aldosterone system were also investigated. Eleven patients (8 women and 3 men aged 62 +/- 3 years) with untreated and uncomplicated EH were included in the study after a 2-week placebo period and kept on a diet containing 120 mmol sodium and 80 mmol potassium daily. In all patients treated once daily with 1 mg of guanfacine for 4 weeks, the drug-induced changes in plasma levels of VP and aldosterone (ALD), plasma renin activity (PRA), plasma osmolality, BP and heart rate were determined. A marked reduction in plasma VP levels (p less than 0.001) was observed and this was accompanied by a significant fall in mean arterial blood pressure (p less than 0.001). No significant changes in heart rate, plasma osmolality, PRA and plasma ALD levels were found. The results suggest that guanfacine might suppress VP secretion via alpha 2-adrenoceptors without significantly affecting renin-angiotensin-aldosterone system.(ABSTRACT TRUNCATED AT 250 WORDS)

Ectopic production of human chorionic gonadotropin in transitional cell carcinoma of the bladder. An immunohistochemical study.

A retrospective histopathological and clinical analysis of 43 patients with transitional cell carcinoma of the bladder, attending our institution between March 1986 and April 1989, was performed. The indirect immunoperoxidase method was used for the demonstration of human chorionic gonadotropin production in transitional cell carcinoma cells. Nine of the 16 grade III tumors stained positive for human chorionic gonadotropin, while grade I and grade II tumors remained unstained. Our results suggest that the presence of human chorionic gonadotropin in tumor cells is a strong evidence of dedifferentiation, and its association with patient prognosis needs further investigation, especially in high-grade, low-stage tumors.

The effect of vitamin E therapy on plasma and erythrocyte lipid peroxidation in chronic hemodialysis patients.

The effect of vitamin E therapy on plasma and erythrocyte (RBC) lipid peroxidation was investigated in patients undergoing chronic hemodialysis. Before vitamin E therapy, both plasma and RBC lipid peroxidation values of chronic hemodialysis patients were significantly higher than those of healthy controls. Treatment with vitamin E (300 mg/day) for 1 month resulted in a significant decrease of lipid peroxidation. Vitamin E therapy may be a promising approach to prevent peroxidation of membrane lipids in chronic renal failure.

Thin film retardation plate by oblique deposition.

The birefringent property of obliquely deposited metal oxides was studied with a view to applying it to optical retardation plates. By finding favorable conditions to form transparent films of large retardation and low opacity, we developed homogeneous quarterwave plates with a bilayered structure 60 x 250 mm in size and ~3 microm thick on glass substrates. These retardation plates can work with a normally incident light based on form birefringence caused by the characteristic anisotropic microstructure inside the film. They showed promising optical properties which can compete with the conventional types of retardation plate.