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At least 811 records · Page 45Linked to original sources
PubMed1994

Limited trypsin proteolysis renders carnitine palmitoyltransferase insensitive to inhibition by malonyl-CoA in patients with muscle carnitine palmitoyltransferase deficiency.

Carnitine palmitoyltransferase (CPT) was studied in muscle homogenates of two patients with muscle CPT deficiency heterozygous for the Ser-113 Leu mutation in the CPT II gene. Total CPT activity was normal in both patients but was almost completely inhibited by malonyl-CoA and Triton X-100 whereas in controls 38% and 58% of total activity remained in the presence of malonyl-CoA and Triton X-100, respectively. The addition of 1% Tween 20 abolished about half of the activity in patients but not in controls. Preincubation of muscle homogenate with trypsin slightly increased the total activity and rendered the activity greatly insensitive to inhibition by malonyl-CoA in both patients and controls. The data support the view that in patients with muscle CPT deficiency both CPT I and II are active, but that CPT II is abnormally accessible to inhibition by malonyl-CoA.

Carnitine O-Palmitoyltransferase↗
PubMed1990

ThioTEPA pharmacokinetics during intravesical chemotherapy and the influence of Tween 80.

A pharmacokinetic study of randomised crossover design was carried out in which eight patients with recurrent stage pTa or pT1 transitional cell carcinoma of the bladder were given thioTEPA (30 mg) in distilled water or in 10% (v/v) Tween 80 (30 ml) intravesically for 2 h, followed 3 months later by the alternative treatment. ThioTEPA and its primary metabolite, TEPA, were measured in plasma and urine using a sensitive and specific chromatographic assay. Large differences between patients were observed in the proportion of thioTEPA absorbed, ranging from 20%-78%. Peak plasma levels of thioTEPA were observed within 1 h of intravesical administration. By 2 h after administration the plasma levels of TEPA were similar to those of thioTEPA and, in contrast to those of the parent compound, remained at a similar level over the next 4 h. The rate of absorption of thioTEPA was not influenced by Tween 80, but it did cause statistically significant increases in mean peak plasma levels (from 101 to 154 ng/ml) and mean AUC values (from 0.376 to 0.496 micrograms h per ml) and a decrease in the mean half-life (from 1.83 to 1.25 h). To obtain plasma levels similar to those achieved after instillation with thioTEPA alone, the dose should be reduced with Tween 80.

Absorption↗
PubMed1994

Pharmaceutical development of a parenteral formulation of the novel anti-tumor agent carzelesin (U-80,244).

The aim of this study was to design a parenteral dosage form for the investigational cytotoxic drug carzelesin. A stable formulation in PET (Polyethylene glycol 400/absolute ethanol/Tween 80, 6:3:1, v/v/v) was developed. The prototype, containing 0.50 mg carzelesin in 2.0 ml PET formulation, was found to be the optimal formulation in terms of solubility, stability and dosage requirements in phase I clinical trials. Quality control of the formulation showed that the pharmaceutical preparation of carzelesin in PET is not negatively influenced by the manufacturing process. Shelf life studies demonstrated that the formulation is stable for at least 1 year, when stored at -30 degrees C in the dark. In addition, the stability of carzelesin in the PET formulation is discussed as a function of temperature, additives and after dilution in infusion fluids.

Antineoplastic Agents↗
PubMed1979

Promoting action of croton oil on gastrocarcinogenesis by N-methyl-N'-nitro-N-nitrosoguanidine in rats.

The promoting effect of croton oil on gastrocarcinogenesis by MNNG was examined in male Wistar rats. Gastric carcinomas were found in five of 10 rats given 83 micrograms/ml MNNG for three months and then 0.02% croton oil with 0.5% Tween 60 as solvent for nine months. No gastric carcinomas were found in rats given MNNG for three months and then Tween 60 only for nine months. The incidence of gastric carcinomas in these two groups was significantly different (p less than 0.05). No tumors were found in rats given only croton oil with Tween 60.

Adenocarcinoma↗
PubMed1975

Surfactants and bioelectric properties of rat jejunum.

The effects of surfactants on bioelectric properties of rat jejunum were determined. Tween 80 (nonionic) and sodium dodecylsulfate (anionic) increased transmural potential differences 20-34% over values in Krebs-Ringer bicarbonate buffer. Short-circuit currents increased 66-112% and net tissue resistance decreased 19-30%. The cationic surfactant cetrimide decreased transmural potential 23%; short-circuit current decreased 32%, and resistance increased 22%. When sulfate replaced chloride in buffer, surfactant effects were minimized or reversed suggesting a role of Cl- flux in the bioelectric effects. Cationic surfactant effects on current and resistance were in the same direction as, but of greater and lesser magnitude, respectively, than alterations observed with bile salts. The current increase was of greater magnitude and resistance decrease less marked. Surfactant molecules may interact specifically with membranes in a more complex manner than simple "detergency".

Animals↗
PubMed1981

The use of membrane-active compounds to examine the structure of the surface membrane of Schistosoma mansoni.

The effects of a variety of lipophilic compounds on the young stage (schistosomulum) and adult Schistosoma mansoni have been studied by measuring the release of 51Cr and 125I-labelled wheat-germ agglutinin from labelled parasites. The compounds could be classified into three groups, one of which described reagents which affected only the schistosomulum. It is concluded that during development, changes occur in the organization of the lipid phase of the parasite membrane.

Amphotericin B↗
PubMed1982

Characterization of rubella virus-induced hemolysis.

We have characterized rubella virus-induced hemolysis, as compared to the virus-induced hemagglutination. A correlation was seen between both activities, when red blood cells from various animals were used in the assays. However the two activities of the virus exhibited different responses to treatments, like freezing and thawing, heating, and Tween 80-ether extraction. These results indicate the two-step nature of the reaction of rubella virus-induced hemolysis: virus adsorption to cells and cell lysis.

Adsorption↗
PubMed1978

Preparation of projection-less particles from influenza virus and their messenger activities in prokaryotic and eukaryotic systems.

A fraction of projection-less particles was prepared from influenza A/Dunedin/4/73 and A/Victoria/3/75 (X-47) (H3N2) by detergent treatment and extraction into ether at 0 degrees C. The activity of this material in stimulating protein synthesis in vitro was studied and compared with that of isolated virion RNA using a) an RNA-dependent E. coli system, and b) a wheat germ system. In the bacterial system the purified RNA had the highest template activity, while in the eukaryotic system the disrupted particle preparation was by far the most active. Translation products were formed with immunological and electrophoretic properties similar to those of several influenza virion proteins. The experiments indicate that, when added in the form of disrupted projection-less particles, RNA from influenza A2 virus is utilized as a template by eukaryotic ribosomes.

Cell-Free System↗
PubMed1980

Degradation of rubella virus envelope components.

Tween-ether treatment of rubella virus, which has no effect on the antigenic and electrophoretic properties of the two envelope glycoproteins, destroys infectivity and enhances haemagglutinating activity. Trypsin treatment alters the electrophoretic pattern of the envelope glycoproteins so that the VPI peak is no longer evident and the VPII peak is reduced. At the same time, both the properties of haemagglutination and infectivity are inactivated but the capacity to combine with neutralizing antibody is retained, which suggests that VPII may be responsible for inducing the production of neutralizing antibody.

Animals↗
PubMed1993

New milk medium for germ tube and chlamydoconidia production by Candida albicans.

A new medium consisting of UHT milk, tween 80 and agar is described for the development of both germ tube and chlamydoconidia by Candida albicans. In total 172 isolates from clinical specimens, including C. albicans (112), C. guilliermondii (4), C. krusei (3), C. parasilopsis (16). C. tropicalis (28), Torulopsis glabrata (6) and Trichosporon beigellii (3), were examined in this medium by using the standard method. A higher percentage (98.2%) of germ tube production by C. albicans was found in this medium than in undiluted serum (90.2%). In addition, only C. albicans was found to be able to produce a high percentage of chlamydoconidia (95.5%) after 48 hours' incubation. In comparison with the conventional medium, corn meal tween 80 agar (21.4%), this new medium gives a significantly higher percentage and abundance of chlamydoconidia production. Being simple, cheap and easy to prepare, the new milk medium is proposed as very practical in the clinical mycology laboratory.

Agar↗