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Biomedical subjects

P Riley

Publications and source records attributed to P Riley.

At least 37 records · Page 2Linked to original sources
PubMed1999

Treatment of lesions of osteomyelitis in the hind flippers of six grey seals (Halichoerus grypus).

Six rescued grey seal (Halichoerus grypus) pups had traumatic injuries to their hind flippers; three had osteomyelitis without fractures, one had a single fracture and associated osteomyelitis, and two had multiple compound fractures and large open wounds. The medical and surgical methods used to treat these lesions are described. A proprietary waterproof covering appeared to be a better method for dressing the wounds than conventional bandaging.

Animals↗
PubMed1999

Deletion of the Cul1 gene in mice causes arrest in early embryogenesis and accumulation of cyclin E.

The stability of many proteins is controlled by the ubiquitin proteolytic system, which recognizes specific substrates through the action of E3 ubiquitin ligases [1]. The SCFs are a recently described class of ubiquitin ligase that target a number of cell cycle regulators and other proteins for degradation in both yeast and mammalian cells [2] [3] [4] [5] [6]. Each SCF complex is composed of the core protein subunits Skp1, Rbx1 and Cul1 (known as Cdc53 in yeast), and substrate-specific adaptor subunits called F-box proteins [2] [3] [4]. To understand the physiological role of SCF complexes in mammalian cells, we generated mice carrying a deletion in the Cul1 gene. Cul1(-/-) embryos arrested around embryonic day 6.5 (E6.5) before the onset of gastrulation. In all cells of the mutant embryos, cyclin E protein, but not mRNA, was highly elevated. Outgrowths of Cul1(-/-) blastocysts had limited proliferative capacity in vitro and accumulated cyclin E in all cells. Within Cul1(-/-) blastocyst cultures, trophoblast giant cells continued to endocycle despite the elevated cyclin E levels. These results suggest that cyclin E abundance is controlled by SCF activity, possibly through SCF-dependent degradation of cyclin E.

Animals↗
PubMed1999

The neonatal presentation of Prader-Willi syndrome revisited.

We describe 6 newborns evaluated for hypotonia, later diagnosed with Prader-Willi syndrome despite the absence of the classical neonatal features of this syndrome. Specific genetic testing for Prader-Willi syndrome should be considered for all neonates with undiagnosed central hypotonia even in the absence of the other major features of this syndrome.

Chromosome Deletion↗
PubMed1999

Reproducibility of thoracic aortic diameter measurement using computed tomographic scans.

OBJECTIVES: Decisions to recommend elective surgical repair of thoracic aortic aneurysms (TAA) may be based on size or expansion rate, which are used as indices of the risk of rupture. Measurement error may thus affect clinical decision-making. In order to evaluate the reproducibility of aortic diameter measurements of TAA, we assessed departmental inter- and intra-observer variability of measurement of pre-selected computed tomographic scan images of aneurysmal segments of the thoracic aorta. METHODS: We compared measurements of minimum aortic diameter made by four observers in 50 pre-selected scans and at different times by two observers using a calliper method and a measurement tool within the scan. Differences in measured dimension were analysed using Wilcoxon's signed ranks test and the repeatability assessed using the method of Bland and Altman. RESULTS: There were no significant inter-observer differences among three observers but there were significant differences between another observer and two other observers (P < 0.05). No significant intra-observer differences existed. The best intra-observer repeatability was 2.25 while the worst inter-observer repeatability was 4.37. The mean and maximum difference in measurement were +/-0.88 mm and +/-8.0 mm, respectively. Variability of measurement increased with aortic diameter. CONCLUSIONS: Calliper measurement of TAA is an acceptable measurement method for surveillance of TAA but appears most accurate with a single observer. Increasing error is seen with increasing diameter which may compound error in estimation of expansion rate. Standardisation of technique is advisable for multiple observers and aortic units should adopt quality assurance protocols to minimise error.

Aortic Aneurysm, Thoracic↗
PubMed1998

The association of asymptomatic bacterial vaginosis with upper genital tract infection.

Objective: To determine whether asymptomatic bacterial vaginosis (BV) is associated with upper genital tract inflammation or bacterial colonization.Methods: Fifty nonpregnant women with intact uteri who planned to undergo gynecologic surgery and had no recent symptoms of vaginal infection were enrolled. We obtained a vaginal swab for Gram stain, endocervical swab for chlamydia and gonorrhea DNA probe testing, and Pipelle endometrial biopsy for aerobic and anaerobic cultures and histology. We correlated surgical findings and histology of available surgical specimens with the microbiologic results. The diagnosis of BV was made according to Speigel's criteria. Bacteria isolated from the uterus were classified as high virulence versus low virulence. Contingency tables were analyzed using the chi-square or Fisher Exact tests.Results: Twenty-one of 50 patients had BV on Gram stain, 3 had intermediate BV, and 3 had unreadable slides. Eleven patients had histologic endometritis, including 7 of the 21 with BV. The association between BV and endometritis was not statistically significant. Thirty-eight patients had a positive endometrial culture; 18 of these also had BV and 3 had intermediate BV. Of patients with a positive endometrial culture, isolates from those who also had BV or intermediate BV were more likely to be highly virulent pathogens compared to those who tested negative for BV (P <.05). No patients had positive gonorrhea or chlamydia tests. Of the 37 patients who underwent abdominal surgery, 20 had visible adhesions. The association between adhesions and endometritis, BV, or positive endometrial cultures was not significant.Conclusion: Patients with asymptomatic BV are more likely than patients without BV to have highly virulent bacteria isolated from the endometrium. BV may predispose to upper genital tract infection.

Journal Article↗
PubMed1998

The Hand1 bHLH transcription factor is essential for placentation and cardiac morphogenesis.

The placenta and cardiovascular system are the first organ systems to form during mammalian embryogenesis. We show here that a single gene is critical for development of both. The Hand1 gene, previously called Hxt, eHAND and Thing1, encodes a basic helix-loop-helix (bHLH) transcription factor that starts to be expressed during pre-implantation development. After implantation, Hand1 expression is restricted to placental trophoblast cells and later to embryonic cardiac and neural crest cells. We generated Hand1-null mutant mice by gene targetting. Homozygous mutant embryos arrested by embryonic day (E) 7.5 of gestation with defects in trophoblast giant cell differentiation. This early mortality could be rescued by aggregation of mutant embryos with wild-type tetraploid embryos, which contribute wild-type cells to the trophoblast, but not the embryo. By E10.5, however, the Hand1-null fetuses derived from tetraploid chimaeras died due to cardiac failure. Their heart tubes showed abnormal looping and ventricular myocardial differentiation. Therefore, Hand1 is essential for differentiation of both trophoblast and cardiomyocytes, which are embryologically distinct cell lineages.

Animals↗
PubMed1998

Demonstration projects in community-based prevention.

Community-based demonstration projects represent the translation of research findings into practice. This article discusses the scientific basis for demonstration projects and illustrates various principles through two large-scale programs: the Health Promotion and Disease Prevention Research Centers and the Community-Based Public Health initiative. These programs have shown several key components for success, including: building effective partnerships, using existing data effectively, adopting a causal model in intervention design, employing appropriate evaluation techniques, using policy change as an intervention, and utilizing the potential of community groups to foster change among professional partners.

Health Promotion↗
PubMed1997

Enhancement of aminolevulinic acid based photodynamic therapy by adriamycin.

This paper reports on studies that evaluate the interaction between delta-aminolevulinic acid (ALA)-based photodynamic therapy (PDT) and adriamycin (ADM) in an animal model system. Two groups of mice bearing a transplantable mammary adenocarcinoma received ADM i.p. in a single dose of 5 mg (low dose) and 30 mg (high dose) per kg body weight. Sixteen or 40 h after administration of the drug, mice were sacrificed, tumours, livers and hearts were removed and porphyrins, enzyme activities and malondialdehyde content were determined. Tumour explants of ADM-treated mice were incubated with ALA and irradiated with an He-Ne laser. Re-implantation of these in vitro PDT-treated explants into test animals showed that inhibition of tumour growth was significantly enhanced by combined treatment when the low dose of ADM was used. There were no significant changes in porphyrin content, ALA dehydratase and porphobilinogenase activities in the tissues analyzed after ADM treatment as compared with control values. ADM toxicity is thought to be related to semiquinone free radical formation with subsequent generation of reactive oxygen species such as peroxide and hydroxyl radical. These species are considered to initiate lipid peroxidation (LPO) and cause DNA damage. In the case of low-dose treatment with ADM a significant increase in the LPO product, malondialdehyde, was observed after PDT whereas with the high-dose regimen no changes were observed. In the case of explants of (non-irradiated) cardiac tissue malondialdehyde production was also found to be dependent on the dose and time of administration of adriamycin. In our in vivo/in vitro model system we have shown that pre-treatment with ADM increased the cytotoxicity of ALA-PDT at a dosage level of ADM which did not raise LPO levels in heart tissue. The mechanism of this effect has not been clearly elucidated but our data suggest that the observed enhancement of PDT may be attributed in part to the weakening of cellular defence mechanisms by the pre-treatment involving free radical generation by ADM.

Adenocarcinoma↗
PubMed1997

Stimulation of tetrapyrrole synthesis in mammalian epithelial cells in culture by exposure to aminolaevulinic acid.

Tetrapyrrole synthesis in CNCM-1221 cells exposed to 0.6 mM aminolaevulinic acid (ALA) was found to be approximately linear over a 6-h period of incubation. The rate was not significantly affected by cell density over a range of 0.015 to 0.15 x 10(6) cells cm(-2) (final cell density). Tetrapyrrole synthesis was not affected by GABA or glutamic acid in concentrations up to 6 mM and 2.72 mM respectively, suggesting that these amino acids, which are similar in structure to ALA, do not competitively inhibit the ALA uptake pathway in these cells. Pre-exposure to haem arginate (up to 100 microM) was inhibitory, presumably by suppression (through the inhibition of ALA synthase) of an endogenous component of the response. The ALA-stimulated response was not modified by co-exposure to AIA (up to 100 mg ml(-1)). Despite significant reduction of protein synthesis, the porphyrinogenic response of cells exposed to ALA was unaffected by cycloheximide (10 microg ml(-1)) or actinomycin D (10 microg ml(-1)) even when cells were preincubated with these agents for 3 h before ALA exposure. Fetal bovine serum (10%) inhibited tetrapyrrole synthesis by 30% but increased the rate of porphyrin export by cells by a factor of 1.5. The uptake of [14C]ALA was shown to be strongly influenced by the density of the cultures. In dense cultures (final cell density of approximately 0.15 x 10(6) cells cm(-2)), the ALA uptake rate was less than 0.8 compared with a maximum rate of 4.2 fmol per cell h(-1) at a cell density of 0.02 x 10(6) cells cm(-2). Since tetrapyrrole synthesis is less affected than ALA uptake by cell density, the resultant discrepancy in ALA incorporation occurring in dense cultures implies that endogenous ALA synthesis is induced in these cells. ALA uptake was not affected by cycloheximide or actinomycin D in serum-free conditions. However, fetal bovine serum decreased external ALA uptake by about 50%. This effect was abrogated by preincubation with cycloheximide.

Aminolevulinic Acid↗
PubMed1997

Beyond law and ethics: an interdisciplinary course in family law and family therapy.

The professions of family therapy and law share many clients and areas of overlap. Law-related coursework in family therapy programs is typically limited to legal, ethical, and professional issues. However, students can also benefit from understanding other areas of overlap, such as divorce, child custody, and mediation. This article discusses the curriculum for an interdisciplinary course that educates both family therapy and law students. The course provides: (1) a substantive education about similarities and differences between the professions, how they operate as systems, and specific areas of overlap, (2) opportunities to learn clinical skills, and (3) opportunities for personal insight about skills, personality types, and negotiation styles, and how these may differ between the professions.

California↗
PubMed1996

Is admission chest radiography of any clinical value in acute stroke patients?

Chest radiographs are frequently requested on admission of patients with a clinical diagnosis of acute stroke. This study assesses their value in subsequent management of these patients. A retrospective analysis of 435 patients with a clinical diagnosis of acute stroke was made. All admission chest radiographs were reviewed to document both radiographic quality and any radiological abnormality. In those patients with an abnormal radiograph, clinical records were reviewed to assess their impact on clinical management. Eighty-six percent of patients had a chest radiograph performed on admission. 77.5% of these films were deemed to be technically unsatisfactory, the commonest problems being positioning and suboptimal inspiration. Radiological abnormality was demonstrated in 61 patients (16.4% of radiographs obtained). Clinical management was altered in 14 of the 61 patients (3.8% of the total number of patients radiographed). Radiological abnormality was missed by the admitting clinicians in four radiographs (1 hilar mass, 2 cases of consolidation, one of pulmonary oedema). One abnormality not clinically suspected was recorded (multiple metastases). We conclude that admission chest radiographs in patients with an acute stroke are not indicated in the absence of appropriate clinical indications.

Acute Disease↗
PubMed1996

Student perceptions of changing answers on multiple choice examinations.

The belief that changing answers on examinations is detrimental persists in spite of empirical research which does not support that belief. While the research in education has consistently shown that changing answers is beneficial, few studies have been done on the behavior and psychological process of changing answers. This qualitative study found that students prefer not to change answers and do not believe it is advantageous to do so. Most students took tests in such a manner that at least a portion of the questions were re-read. Reasons given for changing answers included reconsidering the answers after re-reading the question, mismarking the answer sheet, re-guessing, and receiving a clue later in the test. The students who changed answers often found they had misread the questions initially when they re-read it. Re-reading the question was most likely to result in a change from wrong to right. Re-guessing was not found to be as beneficial to the student scores.

Education, Nursing, Baccalaureate↗
PubMed1995

Creating a culture of change.

The objective of this presentation is to assist companies in creating a culture of change. In the 1970s our manufacturing companies pursued planning as the answer to competitive strength. Throughout the 1980s, we networked with suppliers and customers and smoothed the product flow. Now, in the 1990s, we are focused on the end customer to drive our programs to simplify the process to gain a competitive edge! Each of these answers was correct for its time. Stepping back from it all, however, we can see that the only lasting advantage is the underlying ability to adapt and change; to reinvent our companies again and again amid a rapidly changing, increasingly competitive environment.

Community Participation↗
PubMed1995

A fluoroscopy credentialling programme for orthopaedic surgeons.

We have developed a teaching programme for non-radiologists who use fluoroscopy, which includes techniques for reducing the radiation received by the patient and the surgeon during orthopaedic procedures. The techniques resolve around the radiation protection concepts of time, distance and shielding. The programme has been very successful in reducing the total fluoroscopy times of orthopaedic surgeons; in our institute, durations have been reduced to about 10% of those before the training started. We review the aims and content of our programme.

Education, Medical, Continuing↗
PubMed1994

Fruit and vegetable food frequencies by fourth and fifth grade students: validity and reliability.

OBJECTIVE: Due to the increased emphasis on fruit and vegetable (F+V) consumption and a desire to use the simplest dietary assessment method appropriate to determine F+V intake, we assessed the reliability and validity of weekly and monthly fruit and vegetable food frequency questionnaires (F+V FFQ) among fourth and fifth grade students by comparing them to food records previously validated through school lunch observations. METHODS: The multiethnic sample (primarily African-American and Caucasian) included predominantly lower-middle socioeconomic students from 10 classes at one elementary school. F+V FFQ were printed on optical scanning forms and classroom administered on two occasions. Students completed preprinted food record forms at school and received new forms weekly. To allow comparison between the F+V FFQ and food records, a dietitian abstracted information from the records according to a written protocol and transferred it to F+V FFQ forms covering respective time periods. F+V FFQ were converted to estimated daily servings and aggregated to create five F+V indices plus three summary indices. Statistical analyses included Spearman correlations and paired t-tests. RESULTS: Students demonstrated acceptable reliability in completing food records as well as weekly and monthly F+V FFQ; however, validity was unacceptable for both F+V FFQ versions due to significant overreporting. CONCLUSION: Of the two methods studied, the food record procedure is preferred over the FFQ procedure for collecting self-reported F+V consumption data among fourth and fifth grade students.

Child↗
PubMed1994

Accuracy of fourth- and fifth-grade students' food records compared with school-lunch observations.

Fourth- and fifth-grade students' food records completed by using a labor-intensive approach (with daily monitoring) or a less labor-intensive approach (with weekly monitoring) were compared with school-lunch observations. Records were completed at three elementary schools for 14-23 d by students in 26 classes. Record pages were printed forms with areas for recording items consumed, number of servings, and locations of meals. Students were randomly selected for lunch observation. Kappa coefficients and percent of agreement for interobserver reliability for both approaches combined ranged from 0.43 to 0.91 and 72.6% to 95.5%, respectively, on 24 observations. Pearson correlations for 117 record/observation matches were significant for eight and three of nine meal items for the daily and weekly monitoring approaches, respectively. Thus, students were reasonably accurate in keeping records and more accurate with the more labor-intensive approach. Researchers need to select an approach based on the degree of accuracy desired and available finances.

Child↗
PubMed1994

Initiation of growth inhibition by TGF beta 1 is unlikely to occur in G1.

Type beta transforming growth factors represent a family of polypeptides that modulate growth and differentiation. They exert their effect on target cells through interaction with multiple cell surface receptors. Transforming growth factor-beta 1 has a strong inhibitory action on cell division in mink lung CC164 cells, a process that is initiated by immediate induction of junB and phosphorylation of nuclear protein followed by a reduced expression of cdk4. However, its signal transduction pathways are still unresolved. In this study we report a detailed analysis of cell kinetic events following addition of transforming growth factor-beta 1 to mink lung CCL64 cells. We show that transforming growth factor-beta 1 reduces [3H]thymidine incorporation after a delay of 8 hours, which reaches its nadir at 16 hours. The reduced growth rate is maintained for at least 48 hours as shown by flow cytometric analysis of DNA content. Using time-lapse video microscopy it was shown that control cells double on average every 14.4 hours, whereas the transforming growth factor-beta 1-treated cells have a doubling time of on average 20.3 hours. The difference in intermitotic time is a consequence of a prolonged G1 phase (a shift from 7.5 to 13.5 hours on average). However, changes in intermitotic times occur only after cells have undergone division in the presence of transforming growth factor-beta 1 and treated cells finish the ongoing cell cycle exactly like control cells. From these findings we conclude that transforming growth factor-beta 1 may change cell cycle parameters by interfering with cellular events prior to G1.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗