The effect of biotin supplementation on ascorbic acid metabolism in chickens

The objective of the paper was to show the effect of supplementation of biotin (vitamin H) on vitamin C synthesis in chickens. A significant vitamin C increase was observed in kidneys, adrenal glands, liver, glandular stomach, jejunum wall, caecum wall and in blood plasma. A clear increase in the level of D-glucuronic acid was observed in adrenal glands, jejunum wall, and caecum wall. The activity of L-gulono-gamma-oxidase enzyme clearly increased in adrenal glands, jejunum wall and in stomach. The increase in vitamin C synthesis was found in adrenal glands, jejunum, caecum wall and stomach, but accumulation of vitamin C took place in liver and kidneys. The data imply that the supplementation of biotin accelerates vitamin C synthesis in chickens. Biotin, increasing vitamin C level in the organism, indirectly affects all the processes taking place with the participation of vitamin C.     

The in vitro effect of ascorbic acid on sodium nitrite intoxication]

Cardiotrophin-1 (CT-1) is a recently isolated cytokine belonging to the interleukin-6 cytokine family. In the present study, we show that CT-1 binds to hepatocyte-derived cell lines of rat and human origin with high (Kd = 600-800 pM) and low (Kd approximately 3-6 nM) binding affinities. Treatment of HepG2 cells with CT-1 resulted in the induction of tyrosine phosphorylation of both transducing receptor subunits, gp130 and LIF receptor, and this phosphorylation was completely inhibited by a neutralizing anti-gp130 mAb. Addition of CT-1 to HepG2 or H35 cell cultures induced a dose-dependent production of several acute phase proteins (haptoglobin, fibrinogen, alpha1-acid glycoprotein, alpha2-macroglobulin). Moreover, the use of a neutralizing mAb to gp130 in cultures of HepG2 cells grown in the presence of CT-1, inhibited the induction of acute phase protein secretion, indicating an absolute requirement of gp130 in the formation of a functional CT-1 receptor. Altogether, these results suggest that CT-1 could play an important role in the regulation of hepatocyte metabolism in inflammatory responses.     

Vitamin C intake and plasma ascorbic acid concentration in adolescents

The relationship between vitamin C intake and status was investigated in a group of adolescents (13-14 years old). Dietary intakes were assessed using a 7 d weighted dietary record method, coupled with the collection of duplicate diets. Vitamin C intakes calculated using food composition tables were compared with values obtained by direct analysis of duplicate diets. Vitamin C status was judged via measurement of plasma ascorbic acid (AA) concentration in blood samples taken after a 12-15 h fast. The relationship between calculated and analysed vitamin C intake and plasma AA concentration was examined. Average daily calculated vitamin C intakes, for the group (n 54) as a whole over a 7 d period, gave a good estimate of intake, as judged by prompt analysis of duplicate diets. However, analysed v. calculated intakes were significantly different for approximately one-third of subjects when data were examined on an individual basis. Large discrepancies between analysed and calculated values could not be accounted for on a food group basis. In all but two individuals, calculated vitamin C intake was in excess of the new reference nutrient intake (RNI, part of the new daily reference values (Department of Health and Social Security, 1991)) of 40 mg and all plasma AA concentrations were well above those used to indicate even a moderate risk of deficiency. A relationship between vitamin C intake and plasma AA was observed for both males (n 19) and females (n 35). However, the relationship was much stronger for males who showed a wider range of both intake and plasma AA values.     

Acute effect of ascorbic acid infusion on carbohydrate tolerance

Large doses (1 to 2g/3 hr) of ascorbic acid were administered intravenously to normal weight and obese, nondiabetic subjects. Glucose tolerance and fasting plasma glucose levels were unaffected, despite a 3- to 8-fold rise in plasma concentrations of the vitamin. Infusion of ascorbic acid did not alter fasting serum insulin levels in normal subjects, but was associated with lower concentrations of hormone during an intravenous glucose tolerance test. Plasma glucose, serum insulin, growth hormone, and glucagon levels in obese subjects remained unchanged during the ascorbic acid infusion.     

The effect of ascorbic acid on production of human interferon and the antiviral activity in vitro

The effects of ascorbic acid on interferon production and on the antiviral effect of interferon in cultures of human cells were investigated. Ascorbic acid enhanced the interferon levels produced by human embryo skin and human embryo lung fibroblasts, induced by Newcastle disease virus and by polyinosinic-polycytidylic acid. The same concentrations of ascorbic acid had no effect on interferon production in two lymphoblastoid cell lines induced by Sendai virus. Leucocyte interferon assayed in lung fibroblasts titrated 0.2-0.3 log10 units higher in the presence of 5 mug ascorbic acid than in the absence of the latter.     

The effect of ascorbic acid supplementation on some parameters of the human immunological defence system

We have investigated the effect of ascorbic acid (vitamin C) supplementation on some parameters of the human immune defence system in a group of 25 healthy, male university students. The subjects ingested 1 g ascorbic acid per day for a period of 75 days. Serum levels of IgA, IgG, IgM, C-3 complement component, cortisol and transcortin were measured before and after the ascorbic acid course. Corresponding measurements were performed on a control group of 20 healthy, male university students receiving no extra-dietary vitamin C. Our results showed that ascorbic acid supplementation caused a statistically significant increase in the serum levels of IgA, IgM and C-3 complement. Our study does not permit of conclusions regarding the mechanisms of action of ascorbic acid.     

The effect of ascorbic acid on plasma lipids and oxidisability of LDL in male smokers

OBJECTIVE: The aims of this study were to investigate the effect of ascorbic acid (AA) supplementation on the oxidisability of low density lipoprotein (LDL) in vitro and on plasma lipoproteins under controlled dietary conditions. DESIGN: Randomised single-blind cross-over trial. SETTING: Free living subjects. SUBJECTS: Eight male smokers (age: 25 +/- 2.4 y, BMI: 20.7 +/- 0.5, cigarettes per day: 19.1 +/- 2.4; means +/- s.e.). INTERVENTIONS: Dietary intake was determined in all subjects were advised to achieve an intake as close as possible to the recommended dietary intake of AA (40 mg). After two weeks on the baseline diet, subjects were asked to consume 1 g AA per day for two weeks followed by two weeks of placebo supplementation, or vice versa. In view of the carry-over effects of plasma AA, a wash-out period was incorporated between treatments. Duplicate venous blood samples were collected before and after supplementation and the plasma concentrations of AA, lipids and lipoproteins were determined. The in vitro copper-induced oxidisability of LDL was assessed by monitoring of the absorbance of 234 nm. RESULTS: No changes in the plasma lipids or the oxidisability of LDL were found after AA supplementation compared to placebo. Plasma AA concentrations doubled on average after supplementation indicating that the lack of effect was not a result of poor compliance. CONCLUSIONS: AA supplementation at this dose did not alter plasma lipids of LDL oxidisability in male smokers.     

The effect of ascorbic acid on the activity of lipoprotein lipase in the baboon (Papio ursinus)

The intravenous administration of heparin-released lipoprotein lipase (LPL) into the circulatory system of the baboon (Papio ursinus) is described. After a single heparin injection, a peak value of LPL activity appeared in the circulation with 5 minutes. At low doses of heparin (less than 100 units heparin/kg body mass), LPL disappeared from the circulation in an exponential fashion with a half-life of about 20 minutes. An increase in the heparin dose increased the amount of LPL released into the circulation. In baboons which were deficient in ascorbic acid, less LPL was released into the circulation after specific doses of heparin than in animals that were amply supplied with this vitamin (ascorbic acid 16 mg/kg body mass/day). The separation of plasma LOL, released by heparin, on Sephadex G-150, revealed several distinct molecular species of LPL in the eluant from the columns. In vitro studies indicated that ascorbic acid inhibited cardiac LPL strongly, whereas it had little effect on "post-heparin plasma" LPL. 2somolar concentrations of another reducing agent, mercapto-ethanol, slightly stimulated cardiac LPL in baboons.     

The effect of ascorbic acid and ferric ammonium citrate on iron uptake and storage in lens epithelial cells

Fas antigen (CD95) is a membrane receptor that plays a major role in induction of apoptosis. In surface conjunctival epithelial cells the expressions of Fas, Fas ligand, the apoptotic marker APO2.7 and of HLA DR class II antigen, a membrane marker known to be expressed in inflammatory conditions were investigated. Impression cytology specimens were collected in 65 patients: 20 normal ones, 15 contact lens wearers, 20 receiving chronic topical antiglaucoma treatment and 10 with nonspecific chronic conjunctivitis. Cells were processed for flow cytometry, using monoclonal antibodies to Fas, Fas ligand, APO2.7, HLA DR antigens and a negative isotypic control. Percentages of positive cells were recorded and levels of fluorescence quantified using fluorescent beads at standardized fluorescence intensities. In addition, a human conjunctival cell line was incubated with anti-Fas stimulating antibodies in order to test Fas-induced apoptosis in vitro. Fas was found in all specimens in most of the conjunctival cells, but quantitation of levels of fluorescence showed a significantly higher expression in pathologic eyes than in normal ones. Fas ligand and APO2.7 were variably expressed by conjunctival cells, but in a significantly higher percentage of cells in pathological eyes than in normal ones. In these eyes a strong expression of HLA DR was also observed, whereas normal eyes showed lowest levels. Highly significant correlations were found between Fas, Fas ligand, APO2.7 and HLA DR levels. Anti-Fas antibodies in vitro induced strong apoptosis in epithelial cells as confirmed by APO2.7 expression and DAPI staining. This study confirms that conjunctival epithelial cells normally express Fas antigen, and more inconstantly its ligand, as do corneal ones or keratinocytes. Fluorescence quantitation by flow cytometry showed much higher expression in inflammatory eyes than in normal ones, and demonstrated a strong correlation between apoptotic and inflammatory pathways in the ocular surface.     

The effect of ascorbic acid ingestion on the biochemical and physicochemical risk factors associated with calcium oxalate kidney stone formation

Current information on the pathophysiology, diagnostic process, and treatment of growth hormone deficiency is provided. A case study is provided that shows the positive effects of growth hormone therapy on a patient and his family. Information regarding the intravenous clinician's role in administration of growth hormone and patient teaching also is included.     

Effect of ascorbic acid 2-0-alpha-glucoside on hydrocortisone-induced cataract formation in developing chick embryos: I. Comparison of the preventive effect of ascorbic acid derivatives

The effect of ascorbic acid 2-O-alpha-glucoside (AA-2G) on hydrocortisone (HC)-induced lens opacity in developing chick embryo was examined and compared with those of ascorbic acid (AsA) and ascorbic acid 2-phosphate (AA-2P). The opacity was dose-dependently inhibited by a single administration of 10 or 20 mumol/egg of AA-2G and by three repeated administrations of 1, 3 or 10 mumol/egg of AA-2G. AA-2G was the most effective among the three compounds. Glucose did not enhance the preventive effect of AsA against HC-induced opacity, and neither dehydro ascorbic acid nor glucose also prevented HC-induced cataract. In the histological study, we observed many small vacuoles in the nuclear region of the opaque lens treated with HC. AA-2G inhibited the formation of such vacuoles, an effect closely correlated with the prevention of cataract formation.     

The effect of electron concentration on the thermodynamic properties of two alloy phases in the Al-Zn-Ag system

A reversible electrochemical cell was used to determine the thermodynamic activity of aluminum in a series of α-phase Al-Zn and Al-Zn-Ag alloys, and a dew-point technique was used to determine the thermodynamic activity of zinc in a series of ε-phase Ag-Zn-Al alloys. The compositions investigated for both systems included those at which previous authors had related the stability of the phase to electronic factors. The data are presented in the form of graphs showing the excess relative partial molal Gibbs free energy of aluminum, (Δ•G_A1 ^xs), and zinc, (Δ•G_Zn ^xs), as a function of both mole fraction(X _i ) and electron-to-atom ratio (e/a). The latter curves are interpreted to be indications that the effect of electron concentration upon alloy phase stability has been experimentally isolated. Equations are developed which predict the effects of ternary additions in these alloy systems. The rigid-band model is shown to be incapable of predicting the direction of the effect and an argument based upon electron screening of ion-ion interactions is offered. Formerly Graduate Students, Metallurgy Department, Washington State University, Pullman, Wash. This paper constituted a portion of the theses submitted by RONALD E. MILLER and JERRY L. STRAALSUND in partial fulfillment of the requirements of the degree of Doctor of Philosophy in Engineering Science at Washington State University.     

Effect of ascorbic acid on tumour growth

The growth of tumours in guinea-pigs was observed for 20 weeks after placing them on various doses of vitamin C. Complete tumour regression occurred in 55% of those animals receiving 0-3 mg/kg/day ascorbic acid, whereas animals given 10 mg/kg/day showed tumour inhibition but no regression. In contrast, tumours in animals maintained on 1 g/kg/day ascorbic acid grew without sign of retardation. When increased amounts of ascorbic acid were restored to the diet of scorbutic tumour-bearing animals, tumours which had not regressed responded with enhanced growth. Likewise, animals previously maintained on 10 mg/kg ascorbic acid responded in turn to the additional vitamin with enhanced tumour growth. In contrast, all tumour-bearing animals maintained on 1 g/kh ascorbic acid died within 3 weeks when this dose was replaced with 0-3 mg/kg.     

Formulations of sugars with amino acids or mannitol--influence of concentration ratio on the properties of the freeze-concentrate and the lyophilizate

We have identified a novel lysosome-associated membrane glycoprotein localized on chromosome 3q26.3-q27, DC-LAMP, which is homologous to CD68. DC-LAMP mRNA is present only in lymphoid organs and DC. A specific MAb detects the protein exclusively in interdigitating dendritic cells. Expression of DC-LAMP increases progressively during in vitro DC differentiation, but sharply upon activation with LPS, TNFalpha, or CD40L. Confocal microscopy confirmed the lysosomal distribution of the protein. Furthermore, DC-LAMP was found in the MHC class II compartment immediately before the translocation of MHC class II molecules to the cell surface, after which it concentrates into perinuclear lysosomes. This suggests that DC-LAMP might change the lysosome function after the transfer of peptide-MHC class II molecules to the surface of DC.     

The role of ascorbic acid in oral cancer and carcinogenesis

Severe transient focal cerebral ischemia causes brain infarction with a strong glial reaction. We have studied whether postischemic reactive glial cells express epidermal growth factor receptor (EGFR) following middle cerebral artery occlusion in the rat. We have also looked for signs of proliferating activity, as EGFR is known to be involved in cell growth and proliferation in certain non-neural cells. EGFR was studied using three different antibodies which were found to stain for a tyrosine-phosphorylated protein (p170) corresponding to the membrane-anchored EGFR. Neurons of the control brain were strongly immunoreactive to EGFR, but a decrease of EGFR-immunoreactivity was seen in the ipsilateral brain side from 24 h postischemia due to neuronal loss. However, the presence of abundant glial cells strongly immunoreactive to EGFR became apparent in this area from 4 days postischemia onward. The use of microglial (lectin or OX-42) and astroglial (GFAP) markers showed that these postischemic EGFR-stained cells were reactive microglia/macrophages and astroglia. The subcellular localization of EGFR in reactive microglia/macrophages was compatible with the network of the Golgi apparatus, as revealed with an antibody against a peripheral membrane-bound protein of the Golgi. The presence of abundant proliferating cells in the ischemic brain was detected from 4 days postischemia with an antibody against proliferating cell nuclear antigen. Proliferating reactive microglia/macrophages were abundant within the infarcted brain side, whereas proliferating astrocytes were found mainly in the immediate periphery of the infarct limiting the necrotic area from the undamaged tissue. These proliferating cells were immunoreactive to EGFR. The results show the presence of EGFR in postischemic reactive glial cells and suggest that EGFR-dependent pathways mediate signal transduction in reactive glia following transient focal cerebral ischemia.     

The effect of the electromagnetic vabration on the microstructure, segregation, and mechanical properties of As-cast AZ80 magnesium alloy billet

The effect of the electromagnetic vibration on the properties of 300-mm-diameter AZ80 Mg billets was investigated. The experiments were performed both in the absence and in the presence of electromagnetic vibrating force fields, which were induced by an interaction of variable and stationary magnetic fields. In conventional direct-chill (DC) casting, the AZ80 billet exhibited large dendritic grains with severe segregations of Al and Zn. Applying the electromagnetic vibration during the casting led to significant grain refinement and to greatly reduced segregation in the billet. There was a significant increase in the tensile strength, hardness, and facture elongation of the as-cast AZ80 billet relative to that cast in the absence of the electromagnetic vibration. Microchemical analysis revealed that the application of electromagnetic vibration increased the minimum concentration of Al and Zn in the center of the Mg matrix.     

Effect of ascorbic acid on hyperoxic rat astrocytes

The authors' clinical experience of treating almost exclusively inoperable liver malignancy in 149 patients by cryotherapy is reviewed. There was only one 30-day death; morbidity was modest. Postoperative carcinoembryonic antigen (CEA) changes were extremely predictive of outcome in patients with liver metastases from colorectal cancer. For the group in which CEA levels returned to the normal range, median survival exceeded 1000 days. In addition, the authors reported encouraging results with cryotherapy as an adjunct to resection.