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Biomedical subjects

J E Dalton

Publications and source records attributed to J E Dalton.

6 recordsLinked to original sources
PubMed1992

Hydroxylapatite coating of porous implants improves bone ingrowth and interface attachment strength.

The effect of a plasma-sprayed hydroxylapatite (HA) coating on the degree of bone ingrowth and interface shear attachment strength was investigated using a canine femoral transcortical implant model. Cylindrical implants were fabricated by sintering spherical Co-Cr-Mo particles 500-710 microns in diameter; the nominal implant dimensions were 5.95 +/- 0.05 mm diameter by 18 mm in length. One half of each implant was coated with hydroxylapatite, 25-30 microns in thickness, by a plasma-spray technique. Using strict aseptic technique, the implants were placed through both femoral cortices into defects approximately 0.05 mm undersized. After 2, 4, 6, 8, 12, 18, 26, and 52 weeks, the implants were harvested and subjected to mechanical pullout testing and undecalcified histologic evaluation. The application of the HA coating to porous implants enhanced both the amount of bone ingrowth and the interface attachment strength at all time periods. These differences were statistically significant for the percent of bone ingrowth at the 4-, 6-, 12-, 18-, 26-, and 52-week time periods, and interface shear strength values were significantly different at the 6-, 8-, 12-, 18-, and 26-week time periods. The rate of development of interface strength and bone ingrowth was also more rapid for the HA-coated implants. No evidence of any disruption, mechanical failure, or biologic resorption of the HA coating was observed. The results of the present study--demonstrating a beneficial effect of the HA coating at all time periods--are believed to be due to the use of paired comparisons, which allow assessment of subtle differences that might otherwise have been obscured by normal biological variability.

Analysis of Variance↗
PubMed1992

Family/media approach to HIV prevention: results with a home-based, parent-teen video program.

We describe the first study with a home-based HIV prevention video program for parents and young teenagers. The objectives of the program are to inform parents and teenagers about the causes and prevention of HIV infection and other sexually transmitted diseases, to increase family problem-solving skills, and to increase teen problem-solving and assertiveness skills. The objectives pertain to the goals of increasing skills needed to help teenagers avoid or manage high-risk behaviors and situations. Forty-five families with at least one 12- to 14-year-old were randomly assigned to either experimental (receive video program) or control (no video) conditions in a pretest-posttest design. After 6 months (Follow-Up 1), the experimental and control families were reassessed. The control families next received the video program, and the control families were assessed again (Follow-Up 2). The results indicate increases in parent and teen knowledge and skills only with video viewing. Approaches to improving the video program, particularly with teenagers, are discussed.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Biocompatibility and biofunctionality of implanted materials.

The mechanical and chemical properties of metals, such as titanium, titanium-based alloys and cobalt-based alloys, and ceramics, such as Bioglass and calcium phosphate, make them suitable for implant applications. However, several factors affect the biologic response to these implanted materials. The predominant tissue found at the implant interface is affected by implant stability, material biocompatibility, and implant design and implant placement into the surgical site. Improvements in implant design and surface preparation may improve implant longevity and fixation for all implants materials.

Animals↗
PubMed1988

Construct validity of the Denman Memory for Human Faces test.

Assessed the validity of the Denman Memory for Human Faces (MHF) subtest employing a clinical sample. Factor analysis with marker variables was employed to establish the nature of the extracted factors. The MHF subtest, WAIS-R Verbal (i.e., Information, Vocabulary, and Digit Span) and Performance (i.e., Block Design and Object Assembly) subtests, the Wechsler Memory Scale Mental Control, Paired Associate Learning, 30-min Logical Memory, and 30-min Visual Reproduction, and Benton's Facial Recognition Test were subjected to a maximum likelihood factoring procedure with Varimax rotation. Four factors were extracted which accounted for 72.7% of the variance. Factor I was perceptual-organization, Factor II was verbal comprehension, Factor III was general memory, and Factor IV was attention-concentration. The MHF subtest achieved a substantial loading (i.e., 0.56) on the general memory factor along with Logical Memory (0.54), Visual Reproduction (0.51), and Paired Associate Learning (0.71). Clinical applications of the MHF were discussed.

Adult↗
PubMed1987

Diagnostic errors using the Short Portable Mental Status Questionnaire with a mixed clinical population.

The validity of the Short Portable Mental Status Questionnaire (SPMSQ) was evaluated using two criteria: clinical diagnosis and neuropsychological diagnosis. The 40 study participants represented a mixed clinical sample of neurologic and psychiatric patients, all of whom were or had been inpatients. Laboratory data (CT, EEG, etc.) were available for 45% of the patients. Neuropsychological diagnosis of organic impairment was based on an extensive test battery. The SPMSQ did not significantly relate to either clinical or neuropsychological diagnosis. It is recommended that a "normal" score on the SPMSQ be regarded as nonspecific regarding organic cognitive impairment rather than suggestive of normal brain functioning.

Aged↗