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Biomedical subjects

R L Morgan

Publications and source records attributed to R L Morgan.

At least 19 recordsLinked to original sources
PubMed2003

Creep behavior of bone cement: a method for time extrapolation using time-temperature equivalence.

The clinical lifetime of poly(methyl methacrylate) (PMMA) bone cement is considerably longer than the time over which it is convenient to perform creep testing. Consequently, it is desirable to be able to predict the long term creep behavior of bone cement from the results of short term testing. A simple method is described for prediction of long term creep using the principle of time-temperature equivalence in polymers. The use of the method is illustrated using a commercial acrylic bone cement. A creep strain of approximately 0.6% is predicted after 400 days under a constant flexural stress of 2 MPa. The temperature range and stress levels over which it is appropriate to perform testing are described. Finally, the effects of physical aging on the accuracy of the method are discussed and creep data from aged cement are reported.

Journal Article↗
PubMed1999

MOC-31 aids in the differentiation between adenocarcinoma and reactive mesothelial cells.

BACKGROUND: Evaluation of effusion specimens for the presence of adenocarcinoma often is complicated by the presence of reactive mesothelial cells that can mimic adenocarcinoma. Ancillary studies, in particular immunohistochemistry, can be helpful in making this distinction. MOC-31 is an antibody that recently was reported to be useful in distinguishing adenocarcinoma from mesothelioma in tissue specimens. In this study we examined the utility of this antibody in pleural effusions. METHODS: Eighty-nine archival, formalin fixed, paraffin embedded cell blocks representing 59 adenocarcinomas, 12 other neoplasms (including 6 mesotheliomas), and 18 reactive effusions were retrieved. After protease digestion, recut slides were immunostained with the MOC-31 antibody utilizing a modified avidin-biotin complex technique. Only membrane-based reactivity was considered as positive. RESULTS: In two adenocarcinomas there was insufficient material remaining in the cell block. Among the 57 remaining cases, reactivity was observed in 54 cases. Reactivity also was observed in one of six mesotheliomas and one small cell carcinoma. The remaining cases, including all 18 reactive effusions, were nonreactive. In distinguishing adenocarcinoma from reactive mesothelial cells, the presence of MOC-31 reactivity was found to be 95% sensitive and 100% specific with a positive predictive value of 100% and a negative predictive value of 95%. CONCLUSIONS: MOC-31 is useful in differentiating between adenocarcinoma and reactive mesothelial cells in pleural effusion specimens. Cancer (Cancer Cytopathol)

3,3'-Diaminobenzidine↗
PubMed1998

Characterization of labeled oligonucleotides using enzymatic digestion and tandem mass spectrometry.

A simple and powerful method for the determination of labeling sites on oligodeoxynucleotides (ODN) has been developed. The method is based on the finding that nuclease P1 (NP1) digestions of label-containing ODNs produce site-specific products: 5'-labeled ODNs produce label-nucleotide (L-N); 3'-labeled ODN produces phosphorylated label (pL); and a label in between the ODN termini produces pL-N. Mass spectrometry spectra of these products from the digestion mixture can be easily utilized for structural verification of labeled ODNs such as DNA probes. We also developed a method for the determination of the labeling sites of ODNs with unknown label structures. In this method, NP1 digestion products generate site-specific fragmentation patterns upon collision-induced dissociation. These patterns can be easily recognized and used for the identification of labeling sites of ODNs with unknown label structures. When an ODN is internally labeled, phosphodiesterase digestion may be used to determine the exact labeling site (sequence location). It was demonstrated that these methods can be applied for ODNs with single or multiple labels, and for ODNs with the same or different labels within an ODN.

Alkaline Phosphatase↗
PubMed1997

Common wrist injuries.

Patients with wrist injuries often present to primary care physicians. Many times, mild clinical injury involves significant damage to carpal bones and soft tissue elements. The long-term outcome of these injuries depends on prompt diagnosis and appropriate therapy. Familiarity with the functional anatomy and physical examination of the wrist, accompanied by radiologic evaluation, may aid the physician in differentiating simple sprains from potentially debilitating wrist injuries.

Diagnosis, Differential↗
PubMed1994

Detection of HCV RNA by the asymmetric gap ligase chain reaction.

The ligase chain reaction (LCR) and the gap ligase chain reaction (gLCR) are exponential amplification techniques for the detection of DNA sequences in a sample. Both techniques depend on the enzyme, DNA ligase, to join adjacent probes annealed to a DNA molecule. However, DNA ligase joins DNA inefficiency on an RNA target. Consequently, LCR and gLCR cannot amplify RNA efficiency. RNA detection methods using LCR or gLCR require a cDNA synthesis step. The carryover of four dNTPs from the cDNA reaction inhibits gLCR. Although LCR can use cDNA reaction products directly, background generated by blunt-end ligation does not allow the high sensitivity typically needed for HIV or HCV detection. The asymmetric gap ligase chain reaction (AGLCR) is a modification of gLCR that allows for the detection of RNA by using < or = 3 of the 4 nucleotides in the cDNA step and the gLCR step. Fewer than 50 copies of synthetic RNA transcript can be reproducibly detected. HCV, an RNA virus with no DNA intermediate, was chosen as the initial RNA model system. HCV antibody-positive and normal samples were analyzed, and the results were found to correlate with the results obtained using nested RNA-PCR. AGLCR provides a new nucleic acid amplification technique that can aid in the diagnosis of disease when the detection of RNA is critical.

Base Sequence↗
PubMed1994

The case confessions of a pastoral visitor.

When a bungled catheterization following surgery causes a life-threatening hemorrhage, this Lutheran minister and hospital chaplain finds himself on the receiving end of professional pastoral care. Regretting the times in offered "Gospel platitudes and sugar-coated Bible verses" to suffering patients, the author finds that his experience has brought him closer to God's presence and made him a better minister.

Attitude of Health Personnel↗
PubMed1993

Base composition analysis of oligonucleotides containing apurinic sites.

Upon base composition analysis, oligonucleotides which are labeled at the 3'-terminus with fluorescein or biotin generate an additional, late eluting peak in the HPLC chromatogram. Investigation of this effect revealed the haptens acted as apurinic sites, and phosphodiesterase cleavage of the phosphate bond between the upstream nucleotide and apurinic site is inhibited. Extension of this work with a base-stable apurinic site inserted into all possible junctures of 5'-TGAC-3' tetramers showed this to be a general effect. As a consequence of this work, acid-catalyzed depurination resulting in apurinic sites can be monitored in oligonucleotide synthesis.

Apurinic Acid↗
PubMed1992

Effects of video-assisted training on employment-related social skills of adults with severe mental retardation.

Two studies investigated effects of video-assisted training on employment-related social skills of adults with severe mental retardation. In video-assisted training, participants discriminated a model's behavior on videotape and received feedback from the trainer for responses to questions about video scenes. In the first study, 3 adults in an employment program participated in video-assisted training to request their supervisor's assistance when encountering work problems. Results indicated that participants discriminated the target behavior on video but effects did not generalize to the work setting for 2 participants until they rehearsed the behavior. In the second study, 2 participants were taught to fix and report four work problems using video-assisted procedures. Results indicated that after participants rehearsed how to fix and report one or two work problems, they began to fix and report the remaining problems with video-assisted training alone.

Adult↗
PubMed1991

Current transition assessment practices.

Although researchers have called for a movement away from prediction-related assessments to those which identify specific skill deficits, the extent to which professionals responsible for vocational assessment have shifted their focus is uncertain. The purpose of this investigation was to assess the frequency with which specified prediction-related and skill deficit-related vocational assessment procedures were administered by a sample of secondary-level teachers and employment training specialists. Additionally, the frequency with which these professionals used assessment data to aid in decision making was determined. The results revealed that teachers and employment training personnel used a variety of assessment procedures to make transition decisions. The implications of these findings are discussed.

Aptitude Tests↗
PubMed1991

Regulating behavioral procedures for individuals with handicaps: review of state department standards.

We reviewed standards (i.e., mandatory policies or recommended guidelines) from 39 state departments of special education and 41 state departments of developmental disabilities/mental retardation (DD/MR) to determine how they addressed the use of behavioral procedures. Results indicated that many standards described procedures to change behaviors of individuals with handicaps and identified ways to regulate usage. Major findings were that (a) standards from state departments of DD/MR addressed behavioral procedures more frequently than standards from special education departments; (b) many standards addressed procedures to decrease, but not increase, behavior; (c) several standards identified safeguards to clients' rights, such as prior approval requirements and periodic review of behavioral procedures' effects; (d) some standards prohibited and/or restricted the use of specific procedures, such as those judged to be aversive; (e) about one-fifth of special education standards and two-thirds of DD/MR standards described staff training requirements for using some procedures; and (f) relatively few standards used decision models to select behavioral procedures. Implications of these findings for policy makers, service providers, and future research efforts are discussed.

Aversive Therapy↗
PubMed1990

Comparison of the Test of Nonverbal Intelligence and Wechsler Intelligence Scale for children--revised in rural Native American and white children.

The Test of Nonverbal Intelligence (TONI) and Wechsler Intelligence Scale for Children--Revised (WISC--R) were administered to 46 Native American and white students who were suspected by their classroom teachers of having learning handicaps. Pearson correlations between these sets of IQs ranged from .42 (TONI and WISC--R Performance) to .89 (WISC--R Verbal and Full Scale).

Adolescent↗
PubMed1989

Serum biochemical and hematologic values of normal and Mycobacterium bovis-infected American bison.

Hematologic and serum biochemical tests were used to monitor the health of 3 groups of bison in an experimental study of tuberculosis. Bison were randomly assigned to Mycobacterium bovis-infected, M. bovis-sensitized, and uninfected control groups. Hematologic measurements included total and differential leukocyte counts, hemoglobin (Hb), packed cell volume (PCV), fibrinogen, and plasma proteins. Biochemical tests included serum urea nitrogen, creatinine, aspartate amino transferase, sorbitol dehydrogenase, serum calcium, and serum phosphorus. There were no significant differences (P = 0.05) in any test values between groups of bison. The bison data were combined and compared to similar data of cattle. The mean values for PCV and Hb were higher than values (PCV 24-46%, Hb 8-15 g/dl) for cattle. Mycobacterium bovis-infected bison had a slight increase in the number of blood monocytes and lymphocytes when compared to the uninfected bison but were within the normal ranges for bison and cattle. Other hematologic parameters were within normal ranges reported for cattle. Creatinine levels in all bison were above the normal range (1.0-1.5 mg/dl) for cattle. Phosphorus levels for M. bovis-infected and M. bovis-sensitized bison exceeded the normal range (5.6-8.0 mg/dl) reported for cattle. The level for uninfected bison was near the upper limit of normal for cattle. Mean values for other serum biochemical tests were within the normal ranges reported for cattle.

Animals↗
PubMed1989

Judgments of restrictiveness, social acceptability, and usage: review of research on procedures to decrease behavior.

Research on professionals', consumers', and others' judgments of the restrictiveness, social acceptability, and estimated frequency of use of procedures to decrease behavior was reviewed. General findings were that (a) respondents generally were consistent in rating procedures from least to most restrictive; (b) most respondents agreed that procedures judged more restrictive should be used as a last resort; (c) more restrictive procedures were not frequently used in practice; (d) respondents generally agreed that less restrictive procedures were more socially acceptable, and vice versa; and (e) the social acceptability of procedures changed as a function of contextual variables Problems related to research methodology were discussed and future research directions suggested.

Adolescent↗
PubMed1988

Pathogenesis of Mycobacterium bovis infection in American bison.

Eighteen 12-month-old bison were randomly placed in each of 3 groups (6 animals/group): group-1 bison were exposed to live Mycobacterium bovis, group-2 bison were inoculated with killed M bovis in oil, and group-3 bison were noninfected controls. Six, 6-month-old, tuberculin test-negative calves were placed (pen contact) with group-1 bison 30 days after exposure to M bovis. Tuberculin skin test responses (caudal fold and/or comparative cervical) were detected in all bison in groups 1 and 2 at 2, 4, 6, 10, and 12 months. Tuberculin skin test responses were observed in 2 of 6 calves at 9 and 11 months after pen contact with M bovis-exposed bison (group 1). Statistically significant lymphocyte blastogenic responses to M bovis purified protein derivative were detected in group-1 bison exposed to live M bovis at 2 months after exposure (P less than 0.025). Significant ELISA reactions were detected in sera of bison at 2 months after exposure to killed M bovis in oil (P less than 0.005) and in bison 2 months after exposure to live M bovis (P less than 0.01). Significant tuberculin skin responses, ELISA reactions, or lymphocyte blastogenic responses to M bovis purified protein derivative were not observed in the 6 control bison. Grossly visible tuberculous lesions were observed in lymph nodes and/or lung collected at necropsy in 4 of 6 bison at 12 months after exposure to live M bovis. Microscopic granulomas compatible with tuberculosis were detected in 5 of 6 bison; M bovis was isolated from tissues of each of the 6 bison.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Prediction of ocular irritation by corneal pachymetry.

Corneal pachymetry performed 3 days after application of a variety of test materials to the rabbit eye was found to be predictive of the eye irritation classification determined by observing the ocular response for 21 days. The test materials included NaOH, methanol, isopropanol, acetone, cyclohexanone, hexane and a shampoo. A 0.1-ml sample of the test material was placed in the conjunctival sac in the left eye of each rabbit. Both the left and the right eye of each rabbit were evaluated for irritation and corneal thickness for up to 21 days using a slit-lamp biomicroscope with a pachymeter attachment. On day 3 of observation the mean corneal thickness ratios (treated/control eye) were predictive of the duration of corneal cloudiness (correlation coefficient = 0.86). In addition, these ratios were predictive of the eye irritation classification as determined by a 21-day test (correlation coefficient = 0.98). Corneal pachymetry for determining eye irritation classification is presented as an alternative to the current 21-day test. It is more objective and requires a shorter observation period. Therefore, this method should lessen the cost of eye irritation testing and decrease the duration of discomfort that may occur among the test animals. The greater objectivity may also reduce the intra- and interlaboratory variation and the number of rabbits required for each testing.

Animals↗