PubMed Health⌕ Search

Biomedical subjects

R S Coles

Publications and source records attributed to R S Coles.

At least 19 recordsLinked to original sources
PubMed1991

The effects of metronidazole administration on clinical and microbiologic parameters of periodontal disease.

The purpose of this study was to assay the concentration of metronidazole in gingival fluid, to correlate clinical and microbiologic parameters of periodontal disease to each other and to the gingival fluid concentration of the drug. Ten subjects with a minimum of two contralateral pairs of periodontal pockets of greater than or equal to 5 mm were utilized. One side of the mouth was selected to serve as the root-planed site while the other was left untreated. On day 0, plaque and bleeding-time indexes and probing depths were recorded. Subgingival plaque was analyzed using phase contrast microscopy. When root planing was completed, the subjects were prescribed either metronidazole or placebo three times daily for seven days. Within 24 hours of the last dose, and thereafter at intervals of 1, 2 and 3 weeks, fluid samples were assayed for metronidazole. Clinical and bacterial data were likewise recorded. The results indicate that root planing with metronidazole appears to be more effective in promoting periodontal health than root planing alone. Concentrations of metronidazole ranging from 5 to 20 micrograms/ml were detectable in fluid samples obtained within 24 hours of administration of the last dose. No discernible levels could be found in samples taken at the longer intervals.

Analysis of Variance↗
PubMed1986

Molecular mechanisms of cataractogenesis: IV. Evidence of phospholipid . malondialdehyde adduct in human senile cataract.

Lipid extracts of the human cataractous and normal lenses were analyzed by thin-layer chromatography (TLC) using a solvent system consisting of CHCl3/CH3OH/CH3COOH/H2O (50:25:7:3 by vol.). A novel phospholipid having a Rf intermediate between phosphatidyl ethanolamine (PE) and phosphatidyl serine (PS) was detected besides the four major phospholipids viz., PE, PS, phosphatidyl choline (PC) and sphingomyelin (SP). The novel phospholipid was found to be molybdenum positive and ninhydrin negative having a characteristic fluorescence of Schiff-base conjugate formed between PE, malondialdehyde (MDA) and PS. It was possible to resolve this adduct into PE and PS after acid hydrolysis using two dimensional TLC with CHCl3/CH3OH/NH3 (7 M) (65:25:4 by vol.) as the second solvent. In cataract PE . MDA . PS adduct increased significantly as did diene conjugates and MDA. In plasma membrane lipid extract of cataractous lenses there was a marked increase in fluorescence at 460 nm when excited at 365 nm showing a characteristic fluorescence of a typical Schiff-base conjugate. The evidence suggests that peroxidation of lenticular plasma membrane lipids is one of the molecular mechanisms involved in cataract in the human.

Cataract↗
PubMed1985

Purification and characterization of Escherichia coli xanthine-guanine phosphoribosyltransferase produced by plasmid pSV2gpt.

The enzyme xanthine-guanine phosphoribosyltransferase from Escherichia coli cells harboring the plasmid pSV2gpt has been purified 30-fold to near homogeneity by single-step GMP-agarose affinity chromatography. It has a Km value of 2.5, 42 and 182 microM for the substrates guanine, xanthine and hypoxanthine, respectively, with guanine being the most preferred substrate. The enzyme exhibits a Km value of 38.5 microM for PRib-PP with guanine as second substrate and of 100 microM when xanthine is used as the second substrate. It is markedly inhibited by 6-thioguanine, GMP and to a lesser extent by some other purine analogues. Thioguanine has been found to be the most potent inhibitor. The subunit molecular weight of xanthine-guanine phosphoribosyltransferase was determined to be 19 000. The in situ activity assay on a nondenaturing polyacrylamide gel electrophoresis gel has indicated that a second E. coli phosphoribosyltransferase preferentially uses hypoxanthine as opposed to guanine as a substrate, and it does not use xanthine.

Electrophoresis, Polyacrylamide Gel↗
PubMed1982

Acute retinal necrosis.

Acute retinal necrosis represents a distinct, recently recognized clinical syndrome. Four patients who presented with rapid visual loss associated with uveitis and coalescent areas of retinal necrosis, followed by development of retinal detachments were examined. This paper emphasizes the following: (1) unilateral involvement does occur, (2) the distribution of lesions can be peripheral or central, and (3) early lesions are not associated with retinal vascular abnormalities either clinically or angiographically. Signs and symptoms are suggestive of an infectious process, possibly viral.

Acute Disease↗
PubMed1982

Extraction and properties of hemagglutinin from cell wall fragments of Fusobacterium nucleatum.

To study the hemagglutinin of Fusobacterium nucleatum, methods were sought to solubilize and purify this component. When cells of F. nucleatum were ruptured by passage through a French press, the fragments lost virtually all ability to agglutinate human erythrocytes. Extraction of the fragments with 2% Triton X-100 for 30 min at 22 degrees C restored hemagglutinating activity (HA). Hemagglutination by these fragments could be inhibited by arginine, as can hemagglutination by intact bacteria. Treatment of active cell wall fragments with pronase and 2% Triton X-100-EDTA at 37 degrees C or with pronase and 0.1% Triton X-100-EDTA at pH 10.0 allowed recovery of solubilized HA. The former HA was inhibited by arginine (arg+) whereas the latter was not (arg-). Fractionation of the arg+ extract by preparative isoelectric focusing showed that HA was recovered from the gel sections having a pH between 4.5 and 5.5. Hemagglutination by this preparation was still arg+. Chromatography of this hemagglutinin on DEAE-Sephadex increased the specific activity to high levels with a loss of inhibition by arginine. A fraction from the DEAE-Sephadex column containing 10,700 HA units per mg of protein was analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Solubilization at 22 degrees C before electrophoresis revealed three Coomassie blue-staining bands which migrated with apparent molecular weights of about 21,000, 38,000 and 60,000. When the same DEAE fraction was boiled in sodium dodecyl sulfate, electrophoresis revealed only one band with an apparent molecular weight of 21,000.

Arginine↗
PubMed1981

Peripheral uveitis and ulcerative colitis.

A 26-year-old woman developed bilateral peripheral uveitis. This was followed five years later by the onset of ulcerative colitis. To our knowledge this is the first report of a relationship between these two entities. A brief review of the literature is undertaken along with a description of some of the immunologic phenomena common to these two disorders. Systemic manifestations with peripheral uveitis are rarely reported, and we feel that many case of uveitis in patients with ulcerative colitis may go undetected. Therefore the true incidence of uveitis in ulcerative colitis may be higher than is realized. It is emphasized that a complete and extensive ocular examination be made in all patient with ulcerative colitis or other forms of inflammatory bowel disease. In this way, the true relationship between these disorders may be elicited and the presence or absence of a common immunologic disturbance may be determined.

Adult↗
PubMed1980

Agglutination of human erythrocytes by Fusobacterium nucleatum: factors influencing hemagglutination and some characteristics of the agglutinin.

Various aspects of agglutination of human erythrocytes by fusobacterium nucleatum were examined. Titration experiments done in buffered saline at pH 6 to 10 showed the same agglutination endpoint. The presence of high concentrations of NaCl in reaction mixtures did not alter titers, but KCl in concentrations of 0.5 to 3.6 M increased titers twofold. The agglutinin was inactivated by heat, acid, alkali, 5% Formalin, and the proteolytic enzyme subtilopeptidase A and therefore appeared to be a protein. Treatment of bacterial cells with 2-mercaptoethanol had no effect. Hemagglutination inhibition experiments revealed that arginine and other compounds containing a guanido group as part of their structure were inhibitory at low concentrations. Various hexoses, some hexose derivatives, and most common metal ions, when added to bacterium-erythrocyte mixtures, had no effect. The binding of dansyl-L-arginine to bacteria, but not erythrocytes, was demonstrable by ultraviolet fluorescence microscopy.

Agglutinins↗
PubMed1979

Central serous retinopathy. A generalized disease of the pigment epithelium.

Among cases of central serous retinopathy, patients have been isolated with retinal pigment epithelial (RPE) and sensory retinal detachments. An analysis of 104 cases occurring during the period from 1972 to 1977 indicates that this disorder is frequently bilateral and that it is associated with different disturbances of the epithelial cell layer, i.e. foci of leakage, transmission defects and serous detachments. Based upon the angiographic studies in 76 cases, we propose the following classification for cental serous retinopathy: I. Unilateral Retinopathy. (A) Uniocular involvement: (1) with focal leakage but no other RPE changes; (2) with focal leakage and other RPE changes; (3) with focal leakage, RPE changes and an exudative retinal detachment. (B) Binocular involvement: (1) mild; (2) moderate; (3) severe (with an exudative retinal detachment in the affected eye). II. Bilateral Retinopathy. (A) Mild; (B) moderate, (C) severe (in association with bilateral exudative retinal detachments). This classification emphasizes the fact that central serous retinopathy, whatever its etiology, represents a generalized affectation of the pigment epithelium and should be construed as a potentially serious disorder requiring thorough evaluation and follow-up care.

Adult↗
PubMed1975

The effect of coenzyme leakage and replacement on the growth and metabolism of two fusobacteria.

Suspensions in water of two species of Fusobacterium leaked several coenzymes when incubated at normal growth temperatures. Chromatography of filtrates from these suspensions revealed the presence of NAD, NADP, FMN, tetrahydrofolic acid and, in one of the two, pyridoxal phosphate. Analyses of some enzymic activities in whole organisms demonstrated deficiencies in coenzymes:glutamate dehydrogenase was virtually inactive in the absence of added NAD; tryptophanase activities were diminished by washing but the extent differed between strains; histidase activity was not decreased by washing or suspension in water or saline. Both lag phase and doubling time increased markedly in severely washed organisms inoculated into fresh medium. Addition of appropriate coenzymes shortened the lag phase for both strains and shortened the doubling time in one.

Adenosine Monophosphate↗
PubMed1975

The urea requirement and urease production of some human species of T-mycoplasmas.

Seven species of human T-mycoplasmas that grow in Fraction A and 20 mug urea/ml died when the urea was omitted. Two species would not grow in Fraction A broth containing 10 mug/urea/ml. The other five strains grew in broth containing 10 mug urea/ml and were adapted by serial passage in broth containing decreasing concentrations of urea to grow in broth containing 2.5 mug/ml urea, but not in broth containing 1.25 mug/ml. Therefore the minimal urea requirement is not the same for the growth of all strains of T-mycoplasmas. In exponential phase broth cultures, urease was detected only intracellularly, none being found in the medium.

Humans↗