PubMed Health⌕ Search

Biomedical subjects

E L Webb

Publications and source records attributed to E L Webb.

17 recordsLinked to original sources
PubMed2006

Case-control, kin-cohort and meta-analyses provide no support for STK15 F31I as a low penetrance colorectal cancer allele.

Recently, homozygosity for T91A single-nucleotide polymorphism (SNP) in the serine/threonine kinase (STK15) gene, which generates the substitution F31I has been proposed to increase the risk of a number of tumours including colorectal cancer (CRC). To further evaluate the relationship between STK15 F31I and risk of CRC, we genotyped 2558 CRC cases and 2680 controls for this polymorphism. We found no evidence that homozygosity for the STK15 31I genotype confers an increased risk of CRC (odds ratio=0.95, 95% confidence interval (CI): 0.74-1.24). We also conducted a kin-cohort analysis to assess risk among first-degree relatives of the CRC cases. The hazard ratio for I/I homozygotes compared to F/F homozygotes was 1.65 (95% CI: 0.39-3.17). A meta-analysis of our case-control data and three previous studies also provided no evidence of an elevated risk of CRC associated with homozygosity. These data provide no support for the hypothesis that sequence variation in STK15 defined by SNP F31I per se confers an elevated risk of CRC.

Aged↗
PubMed1997

Aeroallergen-specific IgE changes in individuals with rapid human immunodeficiency virus disease progression.

BACKGROUND: Progression of human immunodeficiency virus type 1 (HIV-1) infection to the acquired immunodeficiency syndrome (AIDS) is associated with elevated total IgE; however, previous cross-sectional studies have differed in their assessment of concurrent changes in allergic disease prevalence. OBJECTIVE: Assessment of changes in aeroallergen-specific IgE during progression from early to late HIV disease. METHODS: Total IgE, aeroallergen-specific IgE (rye grass, ragweed, Alternaria, dust mite, and cat), IFN-gamma, IL-4, and soluble CD23 (sCD23) were measured in a longitudinal study of 20 subject who had progressed from early-HIV infection (mean CD4 lymphocyte count of 650/mm3) to AIDS (mean CD4 lymphocyte count of 40/mm3) over an average of 4 years. RESULTS: Prevalence of positive aeroallergen specific-IgE assays in early HIV disease (T1 subjects with 13 positives) decreased with progression to late disease (five subjects with nine positive, P = .057), while total IgE increased from a median of 69 to 116 IU/mL. IFN-gamma and IL-4 were unchanged, while sCD23 decreased from a median of 72 to 9 U/mL (P = .0005) with disease progression in the full cohort. In contrast to other subjects, the subgroup of individuals with total IgE > 150 IU/mL in both early and late HIV disease demonstrated an increased frequency of aeroallergen-specific IgE. CONCLUSIONS: The elevation of total IgE associated with rapid HIV-1 disease progression was unexplained by concurrent changes in aeroallergen-specific IgE, IL-4, IFN-gamma, or sCD23. Overall, aeroallergen-specific IgE expression was less prevalent with HIV-1 progression, except in those individuals with elevated total IgE both before and after progression to AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Threaded endodontic dowels: effect of post design on incidence of root fracture.

The use of threaded endodontic dowels is a controversial issue. The purpose of this study was to compare the potential for root fracture resulting from the cementation of nine threaded and three nonthreaded endodontic dowel systems. The clinical crowns of 140 extracted premolars were removed at the cementoenamel junction. The teeth were randomly assigned to the following treatment groups of 10 teeth each: Group 1, endodontically instrumented but not obturated; group 2, instrumented and obturated; group 3, instrumented, obturated, and restored with custom-cast gold dowel and cores; groups 4 and 5, instrumented, obturated, and restored with prefabricated, nonthreaded dowels; and groups 6 through 14, instrumented, obturated, and restored with one of nine prefabricated, threaded dowels. All dowels were inserted according to manufacturer's directions, removed, and cemented with vinyl polysiloxane impression material. Each specimen was demineralized and cleared. Photographs at 1:1 magnification were taken to assess dowel fractures. Fisher's test and chi square analysis were performed to evaluate the differences between post types, and between posted and nonposted controls (p less than 0.05). The results indicate no statistically significant differences between dowel types when compared with each other, regardless of dowel shape, taper, or presence or absence of threads, or when compared to instrumented, nonobturated controls. The amount of remaining dentin and existing root morphology may be a determining factor for endodontically treated teeth to resist fracture during dowel placement.

Cementation↗
PubMed1991

Pulpal response to threaded pin and retentive slot techniques: a pilot investigation.

This investigation compared pulpal response to threaded pin techniques with response to retentive slot techniques. The teeth were restored with composite resin. Twenty-four teeth were assigned to three treatment groups in one Macaca mulatta monkey. Ten teeth (group 1) received 32 TMS 0.021-inch self-threading pins. Ten teeth (group II) received circumferential slot retention 1 mm deep, 0.5 mm inside the dentinoenamel junction. Four teeth (group III) served as controls. Groups I and II were restored with composite resin. Fourteen days later, the teeth were removed, demineralized, serially sectioned, and stained with hematoxylin and eosin. Chi-square analysis indicated more pulp inflammation when self-threading pins were used (p less than 0.5). Pins placed within 0.5 mm of the pulp elicited severe inflammatory responses, and those placed further than 1 mm had minimal effect. Little correlation existed between remaining dentin thickness and adverse pulp response when slot retention was used.

Animals↗
PubMed1989

Tooth crazing associated with threaded pins: a three-dimensional model.

A model for observing the three-dimensional pattern of cracking associated with placement of self-threading retentive pins was developed. Four sizes of self-threading pins were placed in extracted posterior tooth samples. The pins were subsequently removed and the samples coated with butyl acetate lacquer except for the pin channel orifice. Samples were immersed in dye solution followed by a demineralization and dehydration process. Samples were placed in methyl salicylate until cleared. Cleared samples were examined for dye penetration into the pin channel and communication with the pulp chamber. Comparisons were made of the patterns created by the four sizes of retentive pins. Results showed that more extensive cracks occurred with the larger size pins and that crack communication with the pulp chamber occurred more frequently with the larger pins.

Acetates↗
PubMed1984

The efficacy of a potassium-sparing combination of chlorthalidone and triamterene in the control of mild and moderate hypertension. I.

Chlorthalidone 25 mg/triamterene 50 mg in once-daily oral doses was as effective in reducing blood pressure as chlorthalidone 25 mg alone. The decrease in serum potassium was statistically significantly less with the combination than for chlorthalidone. There were no notable differences between the treatments in any other measure of laboratory safety or adverse reactions.

Adult↗
PubMed1984

The efficacy of a potassium-sparing combination of chlorthalidone and triamterene in the control of mild and moderate hypertension. II.

Chlorthalidone 50 mg/triamterene 50 mg in once-daily oral doses was as effective in reducing blood pressure as chlorthalidone 50 mg alone. The decrease in serum potassium was statistically significantly less with the combination than for chlorthalidone. There were no notable differences between the treatments in any other measure of laboratory safety or adverse reaction.

Adult↗
PubMed1984

Chlorthalidone-triamterene: a potassium-sparing diuretic combination for the treatment of oedema.

The efficacy of a once-daily combination of chlorthalidone 50 mg plus triamterene 50 mg or chlorthalidone 100 mg plus triamterene 100 mg was compared to that of chlorthalidone 50 mg or 100 mg. This double-blind study was carried out in eighty-eight patients over a treatment period of 12 weeks. All patients entered the active medication period of 12 weeks after a placebo run-in period of 3 to 7 days, during which pretibial or malleolar pitting oedema averaging 2 to 4 mm developed. All patients started at the lower doses, i.e. forty-one started on chlorthalidone 50 mg plus triamterene 50 mg and forty-seven started on chlorthalidone 50 mg. The protocol provided for doubling the dose (but not for reducing it thereafter) at any time during the 12-week period when control of oedema was deemed inadequate. Eight of the combination therapy patients and sixteen of those on chlorthalidone required the higher doses. By Week 12, 96% of the chlorthalidone plus triamterene patients and 100% of the chlorthalidone patients had shown a reduction of at least 2 mm in depth of pits, and 92% and 72%, respectively, had complete disappearance of oedema. The decreases in pitting oedema were paralleled by mean weight losses of 2.4 kg and 3.1 kg, respectively, for the combination treatment group and the chlorthalidone group. Average serum potassium levels throughout the 12-week treatment period were 3.70 mEq/L for the patients taking the combination compared to 3.41 mEq/L of those taking chlorthalidone.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1983

Effects of preparation relief and flow channels on seating full coverage castings during cementation.

Machined steel dies were used to study the effects of three die modifications on seating full coverage castings during cementation. The die modifications consisted of occlusal channels, occlusal surface relief, and axial channels. Fourteen specimens having one or more forms of die modification were compared with two control specimens having no die modifications. Statistical analysis of the data revealed that the addition of four axial channels to the simulated preparation on the steel die produced a significant reduction in the mean marginal discrepancy during cementation. Occlusal modifications alone failed to produce significant reductions in marginal discrepancies when compared with the control specimens. Occlusal modifications in conjunction with axial channels failed to produce further significant reductions in marginal discrepancies when compared with those reductions observed in specimens having only axial channels.

Cementation↗
PubMed1983

Indapamide in the stepped-care treatment of obese hypertensive patients.

A double-blind study was carried out in obese patients with moderately severe hypertension to assess the efficacy and tolerability of 2.5 mg indapamide as a once-a-day Step 1 drug compared to 50 mg hydrochlorothiazide also as a once-a-day Step 1 drug; to assess the efficacy and tolerability of a fixed daily dose of 2.5 mg indapamide administered concomitantly with methyldopa starting at 500 mg daily; and to compare the findings of efficacy and tolerability of 2.5 mg indapamide daily with those of 50 mg hydrochlorothiazide daily as Step 1 agents when methyldopa is the Step 2 drug. Twenty-nine patients completed the study and were evaluated. Nine patients achieved the study criterion of reduction of average standing diastolic pressure to 90 mmHg or less when treated with Step 1 medication only. Twenty patients required the addition of methyldopa to their Step 1 medication: 10 patients took 2.5 mg indapamide with an average constant daily dose of 1100 mg methyldopa and 10 patients took 50 mg hydrochlorothiazide with an average constant daily dose of 1575 mg methyldopa to achieve blood pressure control. All groups had mean diastolic pressure controlled at or below the 90 mmHg criterion during the period of constant methyldopa dosage for those patients who required Step 2 therapy. There were no significant differences between groups with respect to diastolic pressure during the constant dosage period. The indapamide patients required significantly (p less than 0.05) less methyldopa than did the hydrochlorothiazide patients in order to maintain satisfactory control of diastolic blood pressure. The number of responders was greater in the 2.5 mg indapamide + methyldopa group than it was in the 50 mg hydrochlorothiazide + methyldopa group, and responses were achieved more rapidly in the former group than in the latter. Indapamide (2.5 mg per day) was effective and well tolerated when used alone or as Step 1 medication in combination with methyldopa as Step 2 medication, and it compared favourably in this regard with hydrochlorothiazide.

Adult↗
PubMed1981

Role of surface fimbriae (fibrils) in the adsorption of Actinomyces species to saliva-treated hydroxyapatite surfaces.

We studied the adsorption, morphological, and serological characteristics of selected Actinomyces and related species. Evaluation of uranyl acetate-stained cells by electron microscopy revealed wide variations among strains in the frequency of surface fimbriae. These variations did not always correlate with the percent adsorption to saliva-treated hydroxyapatite of the various Actinomyces strains. However, two strains of Rothia dentocariosa possessing no surface fimbriae and five strains of A. israelii possessing very few surface fimbriae exhibited feeble adsorption to saliva-treated hydroxyapatite. Although the calculated number of adsorption sites on saliva-treated hydroxypatite did not vary widely among the strains tested, significant differences were observed in the affinities calculated for some species or serotypes. The mean affinities for strains of A. viscosus serotype 2 and A. naeslundii serotype 3 were similar, and these strains adsorbed well to saliva-treated hydroxyapatite. The mean adsorption and affinity for the A. naeslundii strain serotype 1 and all strains of A. israelii tested were significantly less than those determined for the A. viscosus serotype 2 or A. naeslundii serotype 3 strains. Adsorption inhibition activity of antiserum to strain T14V, previously shown to be solely related to antibodies in immune serum directed against the VA1 fimbria (fibril) antigen, was removed by preadsorption of the antiserum with most A. viscosus and A. naelundii strains, but not with A. israelii strains. This suggests some cross-reactivity among strains of A. viscosus and A. naeslundii but not A. israelii. Adsorption to saliva-treated hydroxyapatite of all A. viscosus and A. naeslundii strains tested was strongly inhibited by fimbriae isolated from A. viscosus strain T14V. Collectively, these data suggest that the adsorption of certain A. viscosus and A. naeslundii strains is mediated by surface fimbriae, many of which appear serologically cross-reactive with strain T14V fimbriae.

Actinomyces↗
PubMed1979

Multisectional mold for fabrication of prosthetic ears.

The use of a multisectional stone mold is advocated for the fabrication of prosthetic ears. Less force is required in the deflasking procedure with this technique, reducing the risk of fracturing the mold or tearing the prosthesis. This technique requires more time and care in the flasking procedure. Convergence of the sections is of particular importance. The potential for multiple section lines may result in a need for more surface finishing of the prosthesis.

Ear, External↗
PubMedDate not supplied

Effect of 1- and 4-minute treatments of topical fluorides on a composite resin.

The purpose of this in vitro study was to compare the effects of a 1-min immersion and of 4-min immersions in an acidulated phosphate fluoride (1.23% APF) foam, a 1.23% APF gel, a 2.0% sodium fluoride (NaF) gel, and water on surface topography and on weight of a composite resin (APH). Forty composite resin specimens were placed into eight groups (N = 5 each). For each treatment, a group of specimens was immersed for either 1 or 4 min (four 1-min immersions). Specimens were weighed before and after each immersion. The surface topography of two scanning electron micrographs of each specimen was scored visually by two investigators. Inter-rater reliability was r = 0.75 (intraclass correlation coefficient). There were no significant differences in the mean visual scores or weight among the 1-min immersion groups. Significantly greater surface changes and weight loss of this composite resin occurred following 4-min immersions in either 1.23% APF foam or gel as compared with those immersed in either 2.0% NaF gel or water (P 0.0001; one-way ANOVA, Tukey's Studentized Range Test).

Acidulated Phosphate Fluoride↗