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Biomedical subjects

P Murray

Publications and source records attributed to P Murray.

At least 109 records · Page 6Linked to original sources
PubMed1989

A longitudinal study of the contribution of dental experience to dental anxiety in children between 9 and 12 years of age.

Dental records of a group of children of both sexes were examined systematically over a period of 3 years to determine if the quantity and quality of their dental experience would be associated with increases in dental anxiety. The study was a follow-up of an earlier cross-sectional survey in which older children had demonstrated increases in dental anxiety with age. According to the evidence obtained from their dental records, the children were divided into four groups depending on their patterns of attendance (regular/irregular) and whether or not they had received invasive treatment. The results indicated that children who did not receive invasive treatment during the period under scrutiny were significantly more anxious than those who had. On the other hand, the dental anxiety of children who attended regularly and received invasive treatment did not change significantly. This applied to boys and girls alike.

Age Factors↗
PubMed1989

Acetabular cup-siting device for total hip arthroplasty.

A method for improving acetabular cup positioning at arthroplasty is introduced. The anatomic and engineering principles involved are explained. The device used for this method of siting is described. The method was tested in cadaver experiments and resulted in a 380% improvement of anteversion-retroversion position and a 370% improvement in abduction position over conventional siting. The value of this method in conventional and revision arthroplasty is suggested.

Cadaver↗
PubMed1989

Effect of rotary electric toothbrush versus manual toothbrush on periodontal status during orthodontic treatment.

Adolescents with fixed orthodontic appliances frequently have increased levels of plaque accumulation and gingivitis. The purpose of this study was to determine whether a rotary electric toothbrush would be more effective than conventional toothbrushing in maintaining periodontal health in these patients. Forty adolescent patients were divided into equal groups matched for sex and age. Before and during placement of orthodontic appliances, one group was instructed in use of the rotary electric toothbrush and the other in the use of a conventional toothbrush; these instructions were reinforced at monthly visits thereafter. Baseline clinical assessments of Plaque Index, Gingival Index, and bleeding tendency were made on six standard teeth before appliances were placed. assessments were repeated at 1, 3, 6, 9, 12, and 18 months after appliances were placed. Intragroup and intergroup differences were tested by a two-way analysis of variance. At baseline there were no significant differences between the two groups for any study variable. During the 18-month study period, however, plaque accumulation and gingivitis increased significantly over baseline levels in the control group (p less than 0.01) but remained stable in the group using the rotary electric toothbrush. In addition, the control group showed significantly greater plaque (p less than 0.01), gingival inflammation (p less than 0.001), and gingival bleeding on probing (p less than 0.001) than did the treatment group from the 1- to 18-month examinations. These data suggest that the rotary electric toothbrush is more effective than conventional toothbrushes for removing plaque and controlling gingivitis in adolescents during orthodontic treatment with fixed appliances.

Child↗
PubMed1989

Standardization of disk diffusion and agar dilution susceptibility tests for Neisseria gonorrhoeae: interpretive criteria and quality control guidelines for ceftriaxone, penicillin, spectinomycin, and tetracycline.

A six-laboratory study developed a standardized method for determining the susceptibilities of Neisseria gonorrhoeae strains to penicillin, tetracycline, spectinomycin, and ceftriaxone. Three quality control organisms were also selected, and quality assurance guidelines were initially generated for the disk diffusion and agar dilution methods. The medium recommended for gonococcal susceptibility testing was GC agar with a defined "XV-like" supplement. The supplement should be free of cysteine, a component implicated in the inactivation of some newer beta-lactam compounds. Penicillin, tetracycline, spectinomycin, and ceftriaxone were stable in agar plates stored at 3 to 5 degrees C for at least 2 weeks. Numerous GC agar and drug disk lots were used during the trials without significant variation in test results. Several other gonococcal strains were recommended for additional medium quality assurance. The disk quality control zone limits were established for N. gonorrhoeae ATCC 49226 (formerly CDC F-18) and Staphylococcus aureus ATCC 25923. MIC quality control ranges were also developed for N. gonorrhoeae ATCC 49226 and S. aureus ATCC 29213. The interpretive criteria for penicillin were as follows: susceptibility, greater than or equal to 47 mm (diameter of inhibition zone) (less than or equal to 0.06 micrograms/ml [MIC]); resistance, less than or equal to 26 mm (greater than or equal to 2 micrograms/ml). For tetracycline they were as follows: susceptibility, greater than or equal to 38 mm (less than or equal to 0.25 microgram/ml); resistance, less than or equal to 30 mm (greater than or equal to 2 micrograms/ml). For spectinomycin they were as follows: susceptibility, >/= 18 mm (</= 32 micrograms/ml); resistance, </= 14 mm (>/= 128 micrograms/ml). For ceftriaxone susceptibility, the criterion was >/= 35 mm (</= 0.25 micrograms/ml) with no other category. Criteria of </= 19 mm for plasmid-mediated resistances to penicillin and tetracycline were also confirmed. The false-susceptibility errors were </= 1% with these criteria.

Ceftriaxone↗
PubMed1989

Effect on periodontal status of rotary electric toothbrushes vs. manual toothbrushes during periodontal maintenance. I. Clinical results.

The purpose of this study was to compare the Rotadent rotary electric toothbrush with conventional toothbrushing for its effectiveness in controlling supragingival plaque and gingival inflammation in periodontal maintenance patients. Forty subjects who had received periodontal treatment, including periodontal surgery, for moderate to advanced periodontitis and were on a 3-month periodontal maintenance were divided into two equal groups matched for age and sex. One group used conventional toothbrushing, dental floss, and toothpicks and the other used only the rotary electric toothbrush for a 12-month study period. Single-blind clinical assessments (Plaque Index, Gingival Index, bleeding tendency, pocket depth, and loss of attachment) were made at baseline and at 3, 6, 9, and 12 months after baseline. Subgingival debridement was performed 1 week after the baseline assessment and the 6- and 12-month examinations. Plaque removal was reinforced at 3-month intervals. Both groups had significantly improved scores (P less than 0.01) for Gingival Index and bleeding tendency during the 12-month period, but no differences were found between the groups at any examination. These results indicate that the rotary electric toothbrush is as effective for plaque removal and control of gingival inflammation as a combination of conventional toothbrushing, flossing, and toothpicks for patients in periodontal maintenance.

Adult↗
PubMed1988

Breast cancer in relation to early use of oral contraceptives. No evidence of a latent effect.

A long-term effect of oral contraceptives (OCs) on breast cancer risk has been suggested as an explanation for some studies' failure to detect an association between OCs and breast cancer. To address this latency hypothesis, we analyzed data on 4714 case subjects and 4540 control subjects from the population-based Cancer and Steroid Hormone Study. No support was evident for a latent effect of OCs on breast cancer risk through age 54 years: among parous women who had cumulated more than six years of OC use before their first term pregnancy, the risk of breast cancer, relative to nonusers before first term pregnancy, was 0.6 at zero to four years after first term pregnancy (95% confidence interval [Cl], 0.2 to 1.8), 0.7 at five to nine years (95% Cl, 0.3 to 1.7), and 1.1 at ten to 14 years (95% Cl, 0.3 to 3.9). Among nulliparous women with more than six years of OC use in total, the relative risk of breast cancer, by interval from last use of OCs, was 1.3 at zero to four years (95% Cl, 0.8 to 2.0), 1.1 at five to nine years (95% Cl, 0.5 to 2.0), and 0.6 at ten to 14 years (95% Cl, 0.1 to 3.7).

Adult↗
PubMed1988

Oral contraceptives and premenopausal breast cancer in nulliparous women.

Characteristics of women with potential for modifying the relationship between use of oral contraceptives (OCs) and the risk of premenopausal breast cancer were investigated using data from the Cancer and Steroid Hormone study, a population-based, case-control study conducted in eight geographic areas of the United States. Cases consisted of 2945 women who were premenopausal and 20-54 years of age when breast cancer was diagnosed between December 1, 1980, and December 31, 1982; controls consisted of 2646 women with no history of breast cancer who were also premenopausal and 20-54 years of age when selected during the same period. Results are presented with the cases and controls divided into eight groups on the basis of age at diagnosis on selection (20-44, 45-54), parity (0, greater than or equal to 1), and age at menarche (less than 13, greater than or equal to 13). Among nulliparous women who experienced menarche before age 13, the relative risk of developing breast cancer in the age interval 20-44 years is estimated to be 1.0 for never-users of OCs (reference), 1.3 for greater than 0-3 years of use (95% confidence intervals 0.7-2.4), 1.3 for 4-7 years (95% CI 0.7-2.6), 2.7 for 8-11 years (95% CI 1.2-6.3), and 11.8 for 12 years or longer (95% CI 1.4-95.7). OC use is not significantly related to the risk of breast cancer among women in any of the other seven groups. These findings suggest that prolonged OC use may accelerate the onset of breast cancer for a small group of susceptible women while having no appreciable impact on overall risk. The findings should be regarded as tentative, however, since they are based upon numerous comparisons and because age of menarche was stratified at 13 years to highlight the concentration of breast cancer risk apparent in our data.

Adult↗
PubMed1988

Choice in the repeated-gambles experiment.

Humans chose 10 times between two roulette wheels projected on a monitor. During the first trial, the left wheel provided a hypothetical $100 with p = .94, and the right wheel provided $250 with p = .39. A titration procedure adjusted the probability of a $250 win across trials to permit estimation of an indifference point between alternatives. In Experiment 1, intertrial-interval duration (25 vs. 90 s) and whether sessions began with an intertrial interval or a trial were varied in a 2 x 2 design in this risky-choice procedure. Risk aversion (preference for the $100 wheel) increased with intertrial interval but was unaffected by whether sessions began with a trial or an intertrial interval. In Experiment 2, all sessions began with a trial, and subjects were informed that the experiment ended after 10 trials. Intertrial-interval duration had no effect on choice. In Experiment 3, intertrial-interval duration and whether subjects were given $10 or $10,000 before beginning were varied among four groups in a 2 x 2 design. In all other ways, the procedure was unchanged from Experiment 2. Intertrial interval had no effect on choice, but the $10,000 groups showed less risk aversion than the $10 groups. These results can be explained more readily in terms of Kahneman and Tversky's (1984) notion of "framing of the prospect" than in terms of Rachlin, Logue, Gibbon, and Frankel's (1986) behavioral account of risky choice.

Journal Article↗
PubMed1987

Breast cancer risk in relation to type of estrogen contained in oral contraceptives.

We report analyses designed to address the recent hypothesis that women who use combination-type OCs containing ethinylestradiol (EE) are at increased risk of breast cancer before age 45, if use of such OCs occurs prior to first term pregnancy (FTP). Our findings, based on data from 1679 cases and 1689 controls, 20-44 years of age, from the population-based Cancer and Steroid Hormone Study, are against the hypothesis. The relative risk of breast cancer by duration of exclusive use prior to FTP of OCs containing EE is estimated to be 1.0 (1-12 months EE use), 1.2 (13-48 months EE use), and 0.9 (49+ months EE use). There was no evidence of a latent effect. Among parous women with 49+ months exclusive use prior to FTP of EE-containing OCs, the relative risk of breast cancer was estimated as 0.9 (0-4 years after FTP) and 0.6 (5-9 years after FTP). Among nulliparous women with 49+ months exclusive use of EE-containing OCs, the relative risk of breast cancer was estimated as 1.0 (0-4 years since first use), 0.7 (5-9 years since first use), and 1.1 (10-14 years since first use). With regard to exclusive use of OCs containing mestranol, parous women who used such preparations long-term before their FTP showed no alteration of breast cancer risk, even 15 years or more after pregnancy. Nulliparous women with exclusive use of ME-containing OCs did show elevations in breast cancer risk, but the magnitude of risk in relation to duration of use and latent interval shows no pattern that suggests a cause-effect relationship.

Adult↗
PubMed1987

Consistency and plausibility in epidemiologic analysis: application to breast cancer in relation to use of oral contraceptives.

Consistency and plausibility are fundamental criteria for judging cause and effect from observational studies. They are applied here to the interpretation of data from a population-based case-control study of oral contraceptives and breast cancer. A preliminary analysis of oral contraceptive use in young nulliparous women, who had no family history of either breast cancer or benign breast disease, showed a statistically significant dose-response, with long-term users (49 months or more) having an apparent 4-fold elevation in risk of early breast cancer. Further analyses, however, revealed striking inconsistencies which were biologically implausible. These effectively undermine cause and effect as an explanation for the initial finding.

Adult↗
PubMed1986

The Stroke Data Bank project: implications for nursing research.

The Stroke Data Bank (SDB) is a systematic prospective study of the diagnosis, clinical course, and outcome of a large series of stroke cases. The SDB uses an interdisciplinary approach, with neurologists, nurse clinicians, epidemiologists, statisticians, and computer scientists collaborating to study stroke research issues, including diagnosis of stroke subtypes, characterization of the course and outcome of each stroke type, and identification of nonclinical factors that influence outcome. Research questions germaine to nursing management of stroke patients include: the identification of acute stroke patients likely to develop life-threatening or recovery-impeding complications; assessment of the impact of stroke on ability to perform activities of daily living; determination of how depression affects functional recovery; and identification of quantifiable measures of stroke outcome.

Activities of Daily Living↗