Dietary supplement use among anticoagulation clinic patients.
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Aged↗
Biomedical subjects
M B Walker
Publications and source records attributed to M B Walker.
Craniofacial malformations: intrinsic vs extrinsic neural crest cell defects in Treacher Collins and 22q11 deletion syndromes.
The craniofacial complex is anatomically the most sophisticated part of the body. It houses all the major sensory organ systems and its origins are synonymous with vertebrate evolution. Of fundamental importance to craniofacial development is a specialized population of stem and progenitor cells, known as the neural crest, which generate the majority of the bone, cartilage, connective and peripheral nerve tissue in the head. Approximately one third of all congenital abnormalities exhibit craniofacial malformations and consequently, most craniofacial anomalies are considered to arise through primary defects in neural crest cell development. Recent advances however, have challenged this classical dogma, underscoring the influence of tissues with which the neural crest cells interact as the primary origin of patterning defects in craniofacial morphogenesis. In this review we discuss these neural crest cell interactions with mesoderm, endoderm and ectoderm in the head in the context of a better understanding of craniofacial malformations such as in Treacher Collins and 22q11 deletion syndromes.
Chromosome Deletion↗
The Mouse Genome Database (MGD): from genes to mice--a community resource for mouse biology.
The Mouse Genome Database (MGD) forms the core of the Mouse Genome Informatics (MGI) system (http://www.informatics.jax.org), a model organism database resource for the laboratory mouse. MGD provides essential integration of experimental knowledge for the mouse system with information annotated from both literature and online sources. MGD curates and presents consensus and experimental data representations of genotype (sequence) through phenotype information, including highly detailed reports about genes and gene products. Primary foci of integration are through representations of relationships among genes, sequences and phenotypes. MGD collaborates with other bioinformatics groups to curate a definitive set of information about the laboratory mouse and to build and implement the data and semantic standards that are essential for comparative genome analysis. Recent improvements in MGD discussed here include the enhancement of phenotype resources, the re-development of the International Mouse Strain Resource, IMSR, the update of mammalian orthology datasets and the electronic publication of classic books in mouse genetics.
Animals↗
Model for superconductivity in ferromagnetic ZrZn2.
We propose that superconductivity in the ferromagnetic state of ZrZn2 is stabilized by an exchange-type interaction between the magnetic moments of triplet-state Cooper pairs and the ferromagnetic magnetization density. This explains why superconductivity occurs in the ferromagnetic state only, and why it persists deep into the ferromagnetic state. The model of this article also yields a particular order parameter symmetry, which is a prediction that can be checked experimentally.
Journal Article↗
Recovery of uncorrected visual acuity after laser in situ keratomileusis or photorefractive keratectomy for low myopia.
PURPOSE: To compare uncorrected visual acuity and refractive error in patients undergoing photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK) between 1 week and 6 months after surgery. METHODS: All eyes underwent PRK or LASIK with the VisX StarS2 excimer laser. We retrospectively analyzed data from 77 random eyes of 77 patients in the PRK group and 76 eyes of 76 patients in the LASIK group. All eyes had a low myopic refractive error (spherical equivalent range, -0.88 diopters (D) to -5.13 D; mean PRK. -2.8 +/- 0.20 D: LASIK, -2.5 +/- 0.22 D). Uncorrected visual acuity and manifest refractive error were evaluated 1 week, 1 month, and 6 months after surgery. RESULTS: Each eye undergoing PRK was paired with an eye undergoing LASIK for a similar level of spherical equivalent. Mean uncorrected visual acuity after 1 week was 0.85 +/- 0.06 (20/25, logMAR 0.12 +/- 0.04) for the PRK group and 1.01 +/- 0.06 (20/20, logMAR 0.01 +/- 0.03) for the LASIK group (p < 0.001). Mean spherical equivalent after 1 week was 0.23 +/- 0.12 D for the PRK group and -0.02 +/- 0.07 D for the LASIK group (p = 0.02). Mean uncorrected visual acuity after 1 month was 1.03 +/- 0.05 (20/20, logMAR 0.02 +/- 0.03) for the PRK group and 1.05 +/- 0.05 (20/20. -0.02 +/- 0.03) for the LASIK group (p = 0.16). Mean spherical equivalent after I month was 0.19 +/- 0.10 D for the PRK group and -0.02 +/- 0.09 D for the LASIK group. This difference was statistically significant (p = 0.02), but was unlikely to be clinically significant. Mean uncorrected visual acuity after 6 months was 1.05 +/- 0.06 (20/20, logMAR -0.01 +/- 0.03) for the PRK group and 1.06 +/- 0.05 (20/20, logMAR -0.14 +/- 0.03) for the LASIK group (p = 0.41). Mean spherical equivalent after 6 months was 0.02 +/- 0.08 D for the PRK group and 0.00 +/- 0.08 D for the LASIK group (p = 0.35). CONCLUSION: Uncorrected visual acuity 1 week after surgery is significantly better in eyes undergoing LASIK than in eyes undergoing PRK. Both procedures provide functional vision by 1 week after surgery. The difference does not relate to refractive error, which was similar between the two groups, but to differences in healing of the epithelium. By 1 month after surgery, there is no difference in mean uncorrected visual acuity between eyes that undergo PRK or LASIK for low myopia.
Cornea↗
Acute haemorrhagic leucoencephalitis complicating sepsis.
A case of acute haemorrhagic leucoencephalitis presenting as fatal septic encephalopathy is reported. The clinical features of this condition are reviewed and the potential for earlier diagnosis is considered.
Adult↗
What's your specialty, Doc? Perioperative nursing.
Perioperative nurses who are contemplating the pursuit of a doctoral degree in nursing need information about the current status and characteristics of doctoral education to make informed decisions. This article addresses questions both philosophic and pragmatic that should be addressed by prospective students. Information sources are identified for assistance with making the selection from the 75 plus programs that offer a nursing doctorate nationwide. Suggested sources include professional organizations as well as current students, faculty, and alumni. Determinations should be based on academic information, such as similarities and differences in degrees awarded; the program of studies leading to the degree; admission and progression standards; research interest of the student relative to identified focus and expertise of program faculty, dissertation process, and university and nursing education resources and services, including financial and technological support. Attainment of the doctorate is presented as an enriching experience that prepares nurses for leadership in both education and health care as clinicians, educators, and administrators. Particular attention should be paid to selecting programs that compare favorably with the published American Association of Colleges of Nursing quality indicators for doctoral programs. There must be strong support in the program from both faculty mentors and peer colleagues, reflective of a community of scholars, pursuing not only individual but also collective wisdom, whereas engaging an individual's mind and soul in the pursuit of new knowledge and skills in an atmosphere of mutual trust and respect.
Academic Dissertations as Topic↗
Incidence and prevention of epithelial growth within the interface after laser in situ keratomileusis.
PURPOSE: To analyze the incidence of epithelial growth within the interface after laser in situ keratomileusis (LASIK) and describe a technique that may prevent its occurrence. METHODS: Results were reviewed for all LASIK procedures performed by two surgeons using identical surgical technique with either the Automated Corneal Shaper or Hansatome microkeratome. After laser ablation, the bed and posterior surface of the flap were irrigated with 0.2 microM filtered basic salt solution, and the surfaces were swept with lint-free sponges to clear the interface of epithelial and other debris. An aspirating lid speculum connected to suction was used to evacuate irrigation fluid and debris from the field. After the flap was smoothed into position, a bandage contact lens was used for the first day after surgery to prevent lifting of the flap edge during blinking. RESULTS: Seven hundred eighty-three eyes of 419 patients had primary LASIK, and 108 eyes had LASIK reoperation. Three eyes developed epithelial growth within the interface, with a minimum of 3 months of follow-up. The interface opacity appeared within 1 month of surgery in all three eyes. Two epithelial nests were small (1.0 and 1.5 mm in diameter, respectively) and did not increase in size on subsequent visits. Neither peripheral epithelial nest affected best-corrected visual acuity or caused any other sequelae. One ingrowth occurred early postoperatively in a case with a donut-shaped flap and was eliminated by transepithelial photorefractive keratectomy (PRK). CONCLUSION: Irrigating, wiping the stromal interface with sponges. aspirating irrigation fluid and debris with a suctioning lid speculum, and use of a bandage contact lens for the first day after surgery during LASIK and LASIK enhancement may markedly reduce the incidence of epithelial growth within the interface.
Acetates↗
The maize tha4 gene functions in sec-independent protein transport in chloroplasts and is related to hcf106, tatA, and tatB.
Proteins are translocated across the chloroplast thylakoid membrane by a variety of mechanisms. Some proteins engage a translocation machinery that is derived from the bacterial Sec export system and require an interaction with a chloroplast-localized SecA homologue. Other proteins engage a machinery that is SecA-independent, but requires a transmembrane pH gradient. Recently, a counterpart to this Delta pH mechanism was discovered in bacteria. Genetic studies revealed that one maize protein involved in this mechanism, HCF106, is related in both structure and function to the bacterial tatA and tatB gene products. We describe here the mutant phenotype and molecular cloning of a second maize gene that functions in the Delta pH mechanism. This gene, thylakoid assembly 4 (tha4), is required specifically for the translocation of proteins that engage the Delta pH pathway. The sequence of the tha4 gene product resembles those of the maize hcf106 gene and the bacterial tatA and tatB genes. Sequence comparisons suggest that tha4 more closely resembles tatA, and hcf106 more closely resembles tatB. These findings support the notion that this sec-independent translocation mechanism has been highly conserved during the evolution of eucaryotic organelles from bacterial endosymbionts.
Amino Acid Sequence↗
Molecular cloning of the maize gene crp1 reveals similarity between regulators of mitochondrial and chloroplast gene expression.
The maize nuclear gene crp1 is required for the translation of the chloroplast petA and petD mRNAs and for the processing of the petD mRNA from a polycistronic precursor. In order to understand the biochemical role of the crp1 gene product and the interconnections between chloroplast translation and RNA metabolism, the crp1 gene and cDNA were cloned. The predicted crp1 gene product (CRP1) is related to nuclear genes in fungi that play an analogous role in mitochondrial gene expression, suggesting an underlying mechanistic similarity. Analysis of double mutants that lack both chloroplast ribosomes and crp1 function indicated that CRP1 activates a site-specific endoribonuclease independently of any role it plays in translation. Antibodies prepared to recombinant CRP1 were used to demonstrate that CRP1 is localized to the chloroplast stroma and that it is a component of a multisubunit complex. The CRP1 complex is not associated detectably with either chloroplast membranes or chloroplast ribosomes. Models for CRP1 function and its relationship to other activators of organellar translation are discussed.
Amino Acid Sequence↗
Psychological factors can predict the response to primary chemotherapy in patients with locally advanced breast cancer.
This study evaluated the possible value of psychological variables in predicting clinical and pathological response to primary chemotherapy. 96 women with newly diagnosed large, or locally advanced, breast cancer (T2 > 4 cm, T3, T4, N2 and M0) participated in a prospective, randomised trial to evaluate the effects of relaxation training with guided imagery and L-arginine on response to primary chemotherapy. Before the first of six cycles of primary chemotherapy, women were assessed using the Hospital Anxiety and Depression Scale (HADS) and the Eysenck Personality Questionnaire (EPQ). The primary outcomes were clinical response (evaluated using standard International Union Against Cancer (UICC) criteria) and pathological response (graded by means of a previously published 5-point scale) following primary chemotherapy. Stepwise linear regressions were used to estimate the predictive value of age, menopausal status, clinical nodal status, tumour size at diagnosis, oestrogen receptor status, dietary supplementation (L-arginine versus placebo), personality (EPQ-L scores), mood (HADS scores) and a psychological intervention. HADS depression score was a significant independent predictor of pathological response to chemotherapy. HADS anxiety score was a significant independent predictor of clinical response. Because the original tumour size before chemotherapy (also a significant predictor of clinical and pathological responses) was taken into account in the analyses, the results cannot be explained in terms of psychobiological factors related to tumour size. This study supports the importance of psychological factors as independent predictors of response to primary chemotherapy in patients with breast cancer. If they can be replicated, these findings have major implications for the management of women with breast cancer. Psychological factors need to be assessed and evaluated in future trials of chemotherapy.
Adult↗
Psychological, clinical and pathological effects of relaxation training and guided imagery during primary chemotherapy.
The diagnosis and treatment of breast cancer are stressful, and stress may be associated with a poorer response to chemotherapy. There is a need, therefore, to develop and evaluate interventions that might enhance quality of life and, possibly, improve treatment response. The effects of relaxation combined with guided imagery (visualizing host defences destroying tumour cells) on quality of life and response to primary chemotherapy, to date, have not been adequately evaluated. Ninety-six women with newly diagnosed large or locally advanced breast cancer (T2 > 4 cm, T3, T4, or TxN2 and M0) took part in a prospective, randomized controlled trial. Patients were randomized following diagnosis to a control condition (standard care) or to the experimental condition (standard care plus relaxation training and imagery). Psychometric tests to evaluate mood and quality of life were carried out before each of the six cycles of chemotherapy and 3 weeks after cycle 6: tests of personality and coping strategy were carried out prior to cycles one and six. Clinical response to chemotherapy was evaluated after six cycles of chemotherapy using standard UICC criteria and pathological response was assessed from the tissue removed at surgery. As hypothesized, patients in the experimental group were more relaxed and easy going during the study (Mood Rating Scale). Quality of life was better in the experimental group (Global Self-assessment and Rotterdam Symptom Checklist). The intervention also reduced emotional suppression (Courtauld Emotional Control Scale). The incidence of clinically significant mood disturbance was very low and the incidence in the two groups was similar. Finally, although the groups did not differ for clinical or pathological response to chemotherapy, imagery ratings were correlated with clinical response. These simple, inexpensive and beneficial interventions should be offered to patients wishing to improve quality of life during primary chemotherapy.
Antineoplastic Combined Chemotherapy Protocols↗
Ultrasound and percutaneous tracheostomy.
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Female↗
Extraversion and exercise addiction.
Extraversion has been suggested as a factor associated with addiction. This claim was tested in relation to exercise addiction. Twelve exercise addicts were compared with 12 nonaddicted individuals who were committed to regular exercise and with 12 nonexercising individuals drawn from the same student population. Addicted exercisers did not differ from nonaddicted exercisers in extraversion, although exercisers as a group were more extraverted than nonexercisers. The results are interpreted as evidence against the claim that extraversion is a component of the addictive personality profile.
Adolescent↗
The psychological and psychiatric effects of rIL-2 therapy: a controlled clinical trial.
It has been suggested that recombinant interleukin-2 (rIL-2) may cause pyschological and psychiatric problems, although the effects of rIL-2 on its own have not been well documented. To evaluate these effects, 17 patients with advanced colorectal cancer took part in a randomised, parallel group study of rIL-2 with chemotherapy (5-fluorouracil and leucovorin) versus chemotherapy alone. Patients were assessed regularly by means of various psychometric tests including the Hospital Anxiety and Depression Scale, the Mood Rating Scale, the Mini-Mental State Examination, the Digit Symbol Substitution Test, the Trail-Making Test and the Benton Revised Visual Retention Test. Rigorous discontinuation criteria were applied to ensure that the effect of time-related variables did not influence the results. Compared with patients who were given chemotherapy alone, patients receiving immunochemotherapy reported reduced energy, impaired confidence, higher depressed mood and more confusion. Immunochemotherapy was rated as more distressing than chemotherapy alone and patients reported a greater incidence of appetite impairment, weight loss, poor concentration and fever. Cognitive assessments indicated that brain dysfunction can be caused by rIL-2. Compared with the control group, patients receiving immunochemotherapy showed significant impairment on Trail Making Test B and the Digit Symbol Substitution Test. One patient developed repeated transient psychotic episodes associated with rIL-2 infusions and another regularly became confused. These effects were not due to sleep deprivation or pyrexia. Treatment with rIL-2 should not be discarded on psychosocial grounds, although in each case the psychological morbidity and adverse effects on quality of life need to be balanced carefully against potential therapeutic benefits.
Antimetabolites, Antineoplastic↗
Cognitive performance and mood after a weekend on call in a surgical unit.
BACKGROUND: Considerable interest and concern have been expressed about junior doctors' hours. This study was carried out to evaluate the emotional and cognitive effects of a weekend on call in a surgical ward. METHODS: Ten surgical house officers were assessed, in counterbalanced design, on four Monday mornings, twice after a weekend off duty and twice after a weekend on call. Cognitive functioning was assessed using the Cognitive Drug Research computerized cognitive assessment system, and emotional state was evaluated by means of the Aberdeen Mood Rating Scale. RESULTS: Following a weekend on call, significant impairment in concentration, speed and power was observed, and the doctors felt less confident, less energetic and more confused. Impaired attention, working memory, long-term memory and confusion were most closely correlated with number of hours worked on Sunday, and tiredness and confusion were related to number of hours slept. CONCLUSION: A weekend on call has significant deleterious effects on cognitive performance and mood. The findings have implications for staffing levels and the design of duty rosters.
Affect↗
The cognitive effects of recombinant interleukin-2 (rIL-2) therapy: a controlled clinical trial using computerised assessments.
It has been suggested that patients undergoing treatment with recombinant interleukin-2 (rIL-2) may develop cognitive impairment. To evaluate these effects, 17 patients with advanced colorectal cancer took part in a randomised, parallel group study of rIL-2 with chemotherapy (5-fluorouracil and leucovorin) and chemotherapy alone. Assessments were carried out daily whilst patients were in hospital and regularly between cycles of treatment using state-of-the-art computerised cognitive assessment, as well as traditional psychometric tests. Rigorous discontinuation criteria were applied to ensure that the effect of time-related variables did not influence the results. One patient developed repeated transient psychotic episodes associated with rIL-2 infusions and another regularly became confused. Computerised cognitive assessments revealed that immunochemotherapy produced significant impairment in various tasks, especially reaction time, picture recognition and vigilance. These effects were not due to sleep deprivation or pyrexia. For most patients, cognitive functioning was restored to the baseline level within 10 days following the cessation of rIL-2. In conclusion, during infusions of rIL-2, some patients experience severe confusion and amnesia which resembles some of the major cognitive impairments associated with dementias such as Alzheimer's disease. Computerised cognitive assessment using the Cognitive Drug Research system provides a feasible, sensitive and reliable method of evaluating cognitive changes in patients with cancer. It could usefully be included in quality of life assessments in clinical trials where treatment-related cognitive changes need to be evaluated.
Aged↗
Conformity in the Asch task as a function of age.
The social conformity paradigm of Asch (1956) was replicated to investigate the relationship between age and conformist behavior. One hundred ten Australian school children and adolescents between 3 and 17 years of age participated in the study. Each participant was placed in the position of being a minority of 1 against a wrong but unanimous majority of 3. The results indicate that conformity decreases with age in perceptually unambiguous tasks. Conflicting evidence from earlier studies can be attributed to task ambiguity in those studies.
Adolescent↗