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Biomedical subjects

R F Taylor

Publications and source records attributed to R F Taylor.

At least 73 records · Page 4Linked to original sources
PubMed1983

"Single-step" orthodontic bonding systems: possible mutagenic potential.

Six commercially available orthodontic direct-bonding resin systems used to attach orthodontic brackets to tooth enamel were tested for bacterial mutagenicity by means of the Ames test. Components of two systems were found to yield positive spot test results with strains of Salmonella typhimurium. Positive spot test results were also obtained on the components applied to orthodontic brackets. Dose response curves for components of these systems were determined for aqueous and DMSO extracts using strain TA-100.

Dental Bonding↗
PubMed1983

The triterpenoid carotenoids and related terpenoids in Staphylococcus aureus 209P.

The carotenoids of Staphylococcus aureus 209P have been identified as triterpenoid (C30) carotenoids. The pigments include members of a carotene dehydrogenation sequence with C30 analogs of phytoene, phytofluene, zeta-carotene, and neurosporene. The major xanthophyll present under the cultural conditions used is a carotenoic acid derived from the C30 analog of neurosporene. A cis-isomer of this major xanthophyll has also been characterized, as have four other xanthophylls. Of the latter xanthophylls, two have been identified as the hydroxy and glycosyloxy derivatives of the major xanthophyll, while the remaining two xanthophylls are carotenoid esters. Squalene and menaquinone MK-8 have also been identified in the bacterium.

Carotenoids↗
PubMed1983

Evaluation of aorto-iliac occlusive disease by intravenous digital subtraction angiography.

Intravenous digital subtraction angiography (DSA) was used to evaluate 22 patients with Leriche syndrome. The technique successfully demonstrated both the level of obstruction and the reconstitution of arterial flow to the lower extremities. In view of the relative safety of DSA, compared with the axillary approach in standard angiography, the authors believe that it should be the initial procedure for presurgical evaluation of Leriche syndrome.

Angiography↗
PubMed1982

A cell-free system for Streptococcus faecium for studies on the biosynthesis of triterpenoid carotenoids.

A cell-free enzyme extract from Streptococcus faecium UNH 564P has been prepared. The extract incorporates either [2-14C]mevalonic acid (MVA) or [1-14C]isopentenyl pyrophosphate (IPP) into squalene and the carotenoids of the bacterium. ATP and manganese ion were found to be absolute requirements for MVA incorporation by the extract. Only manganese ion was found to be an absolute requirement for IPP incorporation by the extract. Other cofactors including magnesium ion, glutathione, potassium fluoride, NADP, and FAD significantly increase the incorporation of both substrates into the S. faecium terpenoids. Isolation and purification of the radioactive terpenoids from the cell-free system confirmed that the carotenoids of S. faecium are triterpenoids.

Adenosine Triphosphate↗
PubMed1982

The biosynthesis of triterpenoid carotenoids in Streptococcus faecium UNH 564P.

Cell-free enzyme preparations from Streptococcus faecium UNH 564P and Phycomyces blakesleeanus strain C5-car10(-) were used to study the incorporation of [14C]isopentenyl pyrophosphate and either all-trans-[4,8,12-3H]farnesyl pyrophosphate (FPP) or all-trans--[4,8,12,16-3H]geranylgeranyl pyrophosphate (GGPP) into squalene and the carotenoids of the organisms. It was found that the triterpenoid (C30) carotenoids of S. faecium are formed by condensation of two molecules of FPP similar to squalene biosynthesis rather than by condensation of two molecules of GGPP with subsequent degradation. Additional studies have shown that carotenoid glucoside biosynthesis in S. faecium extracts is stimulated by the addition of glucose and UDP-glucose. Such glucoside biosynthesis appears maximal in systems exposed to aeration. These results confirm that the triterpenoid carotenoids in S. faecium are symmetrical and are representatives of a unique new class of carotenoids.

Carbohydrate Metabolism↗
PubMed1981

Neutrophil-endothelial cell interactions on endothelial monolayers grown on micropore filters.

We have developed a technique for growing endothelial monolayers on micropore filters. These monolayers demonstrate confluence by phase and electron microscopy and provide a functional barrier to passage of radiolabeled albumin. Neutrophils readily penetrate the monolayer in response to chemotaxin, whereas there is little movement in the absence of chemotaxin. This system offers unique advantages over available chemotaxis assays and may have wider applications in the study of endothelial function.

Blood Vessels↗
PubMed1979

Binding of the Cain quinolinium, NSC 113089, to rat tissue lipid extracts.

The binding characteristics of the cancer chemotherapeutic Cain's quinolinium 6-amino-1-ethyl-4-[p-[[p-[(1-ethylpyridinium-4-yl) amino] phenyl] carbamoyl]-anilino]-quinolinium dibromide (NSC 113089) to lipid extracts from rat kidney, liver, heart and skeletal muscle has been studied. Such binding is saturable with an apparent KD congruent to 1.6 microM. Drug binding to the lipid extracts is displaceable by spermine, spermidine, calcium ions and protons. Spermine is the best displacing agent, achieving half drug displacement from the lipid extracts at approximately 6.3 microM regardless of tissue. The inability of the displacing agents to displace all the NSC 113089 bound to the lipid extracts as well as differences in the amount of agent bound to as compared to amount of drug displaced from the lipid extracts indicate that a number of drug binding sites may be present in the lipid extracts. The similarities of drug binding by rat tissue lipids to similar lipids extracted from normal animal and tumor tissues is discussed.

Animals↗
PubMed1978

Survival after late disc dislodgement of a mitral Wada-Cutter prosthesis.

A 33-year-old woman, 6 years after placement of a Wada-Cutter prosthesis, suffered from free mitral regurgitation secondary to the dislodgement of the disc occulder into the left atrium. She was operated on approximately 14 hours after the onset of symptoms and survived; this patient is the third reported survivor following dislodgement of a Wada disc.

Adult↗