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Biomedical subjects

A Joyce

Publications and source records attributed to A Joyce.

14 recordsLinked to original sources
PubMed1998

Radiographic verification of implant abutment seating.

STATEMENT OF PROBLEM: It is possible to incorrectly seat an abutment on an external hex implant. PURPOSE: This study investigated the theoretical and practical limits of radiographic verification of the complete seating of implant abutments on external hex implants. MATERIAL AND METHODS: A positioning device that could accurately place the film and/or tube head in any vertical relation desired relative to the implant and abutment was fabricated. For all records, a standard abutment was secured to the implant in both a fully seated position (closed) and with the abutment turned approximately 30 degrees and seated atop the implant external hex (open). Digital radiographs were made with the tube head fixed perpendicular to the implant and the film angled at 0, 5, 10, 15, 20, 25, 30, 35, 40, and 45 degrees. The film was then positioned parallel to the implant and the tube head was angled at 0, 5, 10, 15, 20, 25, 30, 35, 40, and 45 degrees. An image of each position was shown to 36 dentists and they were asked if the image was diagnostic for determining the status of the implant/abutment interface. RESULTS: The data were analyzed with a computer statistics program. The group with the tube head changed was analyzed with the Cochran's Q test and revealed a statistically significant (p < 0.0001) change in the diagnostic value of radiographs beginning at 20 degrees. The group with the film angle changed was analyzed with a Pearson chi-square and showed no statistical difference (p = 0.394) for the diagnostic value of any of the film angles. CONCLUSION: Maintaining the tube head to less than 20 degrees from perpendicular to the long axis of the implant resulted in a diagnostic radiograph, regardless of the angle of the film.

Chi-Square Distribution↗
PubMed1997

Antecedents to and outcomes of Rh(D) isoimmunization: Mater Mothers Hospital, Brisbane, 1988-1995.

We analyzed the antecedents and outcomes of Rh(D) isoimmunization in a local population. Forty-two Rh(D) isoimmunized women attending Mater Mothers Hospital for antenatal care were identified through the Mater Hospital Blood Bank database; their records were reviewed for variables including sensitizing events, obstetric interventions and pregnancy outcomes. In this group, 74% of women became sensitized despite receiving anti-D immune globulin, 17% did not receive anti-D appropriately and the other failed to attend for treatment of bleeding in pregnancy. Antenatal sensitization was implicated in 6 women (14%) and potentially responsible for isoimmunization in another 18. Over half of the 80 viable pregnancies in this study group required some form of obstetric intervention. Thirty pregnancies required amniocentesis and 1 in 3 babies underwent either intrauterine or exchange transfusion. Three fetal deaths occurred as a result of severe disease. This study offers information highlighting circumstances in which immunoprophylaxis guidelines have failed to impart protection against Rh(D) sensitization and the consequences of such failures.

Female↗
PubMed1993

Screening of human bladder tumors and urine sediments for the presence of H-ras mutations.

A series of 111 human bladder tumors were screened using oligonucleotide mutant specific probes, restriction enzyme analysis and single-stranded confirmation polymorphism (SSCP) for the presence of H-ras activation events. Thirty-three tumors were found to harbor H-ras mutations where a glycine to valine (G-->T) change in codon 12 was the most common point mutation recorded (26 tumors). Additional mutations involved glycine to cysteine at codon 13 (2 tumors) and glutamine to arginine/lysine/leucine at codon 61 (3/1/1 tumors, respectively). Ambiguous signals recorded with oligonucleotide probes were further analyzed using SSCP analysis revealing the presence of H-ras mutations in restricted regions of some tumors. The apparent sensitivity of SSCP enabled us to extend this study to DNA isolated from urine sediments where 4 of the 9 patients studied showed representation of mutant H-ras. Our study demonstrates a sensitive, non-invasive assay for the screening of urine-borne cells, with no requirement for prior knowledge of the mutational change at the H-ras locus.

3T3 Cells↗
PubMed1983

Is vitamin E the only lipid-soluble, chain-breaking antioxidant in human blood plasma and erythrocyte membranes?

The concentration of lipid-soluble, chain-breaking antioxidants in human plasma and in erythrocyte ghosts have been determined for the first time by an inhibited-autoxidation method. The results are very similar to the concentrations of vitamin E measured for the same blood components by the HPLC method. It is concluded that vitamin E, which is largely present as alpha-tocopherol, is the only significant lipid-soluble, chain-breaking type of antioxidant present in human blood. The concentration of vitamin E in the plasma lipids divided by the concentration of vitamin E in the ghost membrane lipids is approximately a constant despite the large differences in vitamin E-intake and in plasma lipid concentrations in different individuals. Vitamin E/lipid ratios for plasma and ghosts were larger for subjects taking a supplement of alpha-tocopherol acetate of 100 IU per week, compared to nonsupplemented subjects (based on data from a limited number of subjects). A larger supplement of 2800 IU per week did not significantly increase the vitamin E/lipid ratios.

Adult↗
PubMed1979

Professionalism in nursing master's graduates.

The past 10 years have seen a shift in the master's level preparation of nurses. The majority of nurses currently seeking advanced preparation choose clinical specialization as the functional area rather than teaching. Such a shift in focus reflects the ever increasing specialization of services associated with an ever-growing complex society. Although the shift in focus of preparation and the concomitant change in curriculum design have been documented, few scientific investigations have been conducted on the graduates from master's programmes. Of those studies that have been conducted, the majority have focused on the differential personal characteristics of graduate nursing students in different types of programmes. The purpose of the present study was to investigate the relationship between a nurse's area of functional preparation in a master's degree programme and the individual's level of professionalism. The independent variable of the study was functional area of preparation in a master's programme. The dependent variables became enrolment in a formal programme of study, subscription to professional journals, attendance at non-formal educational programmes, number of authored publications, membership in professional organizations and employment in prepared area, as these seemed to reflect the criteria of professionalism explicated by Flexner (1915). The data for the study were gleaned from questionnaires sent to the 637 individuals who had graduated from the programme. Of the 395 questionnaires that were returned, only 272 were usable. This number represented 43% of the graduate population. The chi-square test was used to analyse the data. Each of the chi-square values for association between professionalism and graduate specialty was found to be significant. Postgraduates prepared as teachers met Flexner's criteria more often than did postgraduates prepared as clinical specialists.

Career Choice↗