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Biomedical subjects

C Richardson

Publications and source records attributed to C Richardson.

At least 37 records · Page 2Linked to original sources
PubMed2003

Evaluation of shoulder internal rotator muscle strength in baseball players with physical signs of glenohumeral joint instability.

OBJECTIVES: To identify whether subjects with glenohumeral translational instability present with a strength deficit in their internal rotator musculature, and therefore to determine if general strengthening exercises are warranted for the management of this condition. METHODS: Eighteen male baseball players were allocated to two groups on the basis of expert clinical evaluation of the presence (n=8) or absence (n=10) of shoulder translational instability. A strain gauge was used to calculate the force generated during maximal isometric internal rotation contractions in neutral shoulder rotation and 30 degrees of internal rotation. RESULTS: The Mann-Whitney test identified no significant difference in force production during the maximum contractions in neutral rotation between the two subject groups. In the position of 30 degrees shoulder internal rotation, subjects with glenohumeral translational instability produced significantly greater force than the control group (p<0.05). CONCLUSIONS: High load strength testing cannot be used as a diagnostic tool to identify people with glenohumeral instability. Similarly, heavy resistance strengthening exercises for the internal rotator musculature are not warranted during rehabilitation.

Adolescent↗
PubMed2003

Errors in general practice: development of an error classification and pilot study of a method for detecting errors.

OBJECTIVE: To describe a classification of errors and to assess the feasibility and acceptability of a method for recording staff reported errors in general practice. DESIGN: An iterative process in a pilot practice was used to develop a classification of errors. This was incorporated in an anonymous self-report form which was then used to collect information on errors during June 2002. The acceptability of the reporting process was assessed using a self-completion questionnaire. SETTING: UK general practice. PARTICIPANTS: Ten general practices in the North East of England. MAIN OUTCOME MEASURES: Classification of errors, frequency of errors, error rates per 1000 appointments, acceptability of the process to participants. RESULTS: 101 events were used to create an initial error classification. This contained six categories: prescriptions, communication, appointments, equipment, clinical care, and "other" errors. Subsequently, 940 errors were recorded in a single 2 week period from 10 practices, providing additional information. 42% (397/940) were related to prescriptions, although only 6% (22/397) of these were medication errors. Communication errors accounted for 30% (282/940) of errors and clinical errors 3% (24/940). The overall error rate was 75.6/1000 appointments (95% CI 71 to 80). The method of error reporting was found to be acceptable by 68% (36/53) of respondents with only 8% (4/53) finding the process threatening. CONCLUSION: We have developed a classification of errors and described a practical and acceptable method for reporting them that can be used as part of the process of risk management. Errors are common and, although all have the potential to lead to an adverse event, most are administrative.

Attitude of Health Personnel↗
PubMed2002

PPAR alpha is necessary for the lipopenic action of hyperleptinemia on white adipose and liver tissue.

Adenovirus-induced hyperleptinemia causes rapid disappearance of body fat in normal rats, presumably by up-regulating fatty acid oxidation within white adipocytes. To determine the role of peroxisomal proliferation-activated receptor (PPAR)alpha expression, which was increased during the rapid loss of fat, we infused adenovirus-leptin into PPAR alpha(-/-) and PPAR alpha(+/+) mice. Despite similar degrees of hyperleptinemia and reduction in food intake, epididymal fat pad weight declined 55% in wild-type but only 6% in PPAR alpha(-/-) mice; liver triacylglycerol fell 39% in the wild-type group but was unchanged in PPAR(-/-) mice. Carnitine palmitoyl transferase-1 mRNA rose 52% in the wild-type mice but did not increase in PPAR alpha(-/-) mice. PPAR gamma coactivator-1 alpha rose 3-fold in the fat and 46% in the liver of wild-type mice but was unchanged in PPAR alpha(-/-) mice. Although AMP-activated protein kinase could not be implicated in the lipopenic actions of hyperleptinemia, acetyl CoA carboxylase protein was reduced in the liver of wild-type but not in PPAR alpha(-/-) mice. Thus, in PPAR alpha(-/-) mice, up-regulation of carnitine palmitoyl transferase-1 mRNA in fat, down-regulation of acetyl CoA carboxylase in liver, and up-regulation of PPAR gamma coactivator-1 alpha mRNA in both tissues are abolished, as is the reduction in their triacylglycerol content.

AMP-Activated Protein Kinases↗
PubMed2002

Mechanical closure of the vocal cords with the laryngeal mask airway ProSeal.

We report a case of mechanical closure of the vocal cords with the laryngeal mask airway ProSeal (PLMA) in an anaesthetized, paralysed 59-yr-old, 88 kg female undergoing lower-limb vascular surgery. Near-complete airway obstruction developed after a size-5 PLMA was inserted and the cuff inflated with 20 ml of air. Fibreoptic inspection revealed that the PLMA was correctly positioned, but the vocal cords were closed. Withdrawal of air from the cuff and/or moving the head and neck into the sniffing position resolved this problem.

Airway Obstruction↗
PubMed2001

Comparison of large-scale mammalian cell culture systems with egg culture for the production of influenza virus A vaccine strains.

Different types of microcarriers were assessed for the large-scale culture of influenza virus in the Madin-Darby canine kidney (MDCK) cells. Both porous and solid carriers were examined. A higher titre of influenza A/PR8/34 virus was recovered from cultures using solid (1.3x10(9) PFU per ml) rather than porous carriers (4.0x10(8) PFU per ml). High titres of virus (1.0x10(9) PFU per ml) were also obtained from roller bottle cultures of MDCK cells and the traditional culture technique using embryonated hens' eggs (3.9x10(9) PFU per ml). We found that solid carriers composed of dextran with a positive charge are the most suitable carriers for the large-scale growth of influenza A virus in MDCK cells using serum-free media.

Animals↗
PubMed2001

Post-translational modifications of the beta-1 subunit of AMP-activated protein kinase affect enzyme activity and cellular localization.

The AMP-activated protein kinase (AMPK) is a ubiquitous mammalian protein kinase important in the adaptation of cells to metabolic stress. The enzyme is a heterotrimer, consisting of a catalytic alpha subunit and regulatory beta and gamma subunits, each of which is a member of a larger isoform family. The enzyme is allosterically regulated by AMP and by phosphorylation of the alpha subunit. The beta subunit is post-translationally modified by myristoylation and multi-site phosphorylation. In the present study, we have examined the impact of post-translational modification of the beta-1 subunit on enzyme activity, heterotrimer assembly and subcellular localization, using site-directed mutagenesis and expression of subunits in mammalian cells. Removal of the myristoylation site (G2A mutant) results in a 4-fold activation of the enzyme and relocalization of the beta subunit from a particulate extranuclear distribution to a more homogenous cell distribution. Mutation of the serine-108 phosphorylation site to alanine is associated with enzyme inhibition, but no change in cell localization. In contrast, the phosphorylation site mutations, SS24, 25AA and S182A, while having no effects on enzyme activity, are associated with nuclear redistribution of the subunit. Taken together, these results indicate that both myristoylation and phosphorylation of the beta subunit of AMPK modulate enzyme activity and subunit cellular localization, increasing the complexity of AMPK regulation.

AMP-Activated Protein Kinases↗
PubMed2001

An iron-regulated ferric reductase associated with the absorption of dietary iron.

The ability of intestinal mucosa to absorb dietary ferric iron is attributed to the presence of a brush-border membrane reductase activity that displays adaptive responses to iron status. We have isolated a complementary DNA, Dcytb (for duodenal cytochrome b), which encoded a putative plasma membrane di-heme protein in mouse duodenal mucosa. Dcytb shared between 45 and 50% similarity to the cytochrome b561 family of plasma membrane reductases, was highly expressed in the brush-border membrane of duodenal enterocytes, and induced ferric reductase activity when expressed in Xenopus oocytes and cultured cells. Duodenal expression levels of Dcytb messenger RNA and protein were regulated by changes in physiological modulators of iron absorption. Thus, Dcytb provides an important element in the iron absorption pathway.

Amino Acid Sequence↗
PubMed2001

Soluble CD14 enriched in colostrum and milk induces B cell growth and differentiation.

Induction of resting B cell growth and differentiation requires a complex series of temporally coordinated signals that are initiated on contact with activated helper T cells. These signals complement one another, each rendering the B cell susceptible to factors supporting progressive activation. Here, we demonstrate that soluble CD14 (sCD14) bypasses the physiological sequelae of events that limit B cell activation. B cell growth and differentiation in vitro is induced by both native and recombinant forms of sCD14 at nanomolar concentrations. sCD14-mediated cellular activation does not require membrane CD14 expression, depends on a region of CD14 that is not involved in lipopolysaccharide binding, and requires functional Toll-like receptor 4. Consistent with biological activity of sCD14 in vitro, its administration to neonatal mice enhances Ig secretion. The results presented establish sCD14 as a naturally occurring soluble B cell mitogen of mammalian origin.

Animals↗
PubMed2001

Identification, cloning, and expression of a functional phenylalanyl-tRNA synthetase (pheRS) from Staphylococcus aureus.

Phenylalanyl-tRNA synthetase (pheRS) is unique among aminoacyl tRNA synthetases in that it is a heterotetrameric enzyme composed of two alpha-subunits and two larger beta-subunits. In prokaryotes, the alpha- and beta-subunits of pheRS are encoded by the genes pheS and pheT, respectively. In this report we describe the isolation of a DNA fragment (3.52 kb) containing the pheS and pheT genes from a Staphylococcus aureus (WCUH29) genomic DNA library. Both genes, found as a part of transcriptional operon, were predicted to encode polypeptides which showed strong primary and structural similarity to prokaryotic phenylalanyl-tRNA synthetase alpha- and beta- subunits. We describe the high-level overexpression and purification of recombinant S. aureus pheRS using pheS and pheT genes as part of an artificial operon in Escherichia coli. For comparative analysis we also report a procedure for the purification of native pheRS from S. aureus (Oxford Strain) and demonstrate that Michaelis-Menten parameters for both recombinant and native enzyme, at least for phenylalanine tRNA aminoacylation are comparable.

Amino Acid Sequence↗
PubMed2001

The standardization of Achenbach's Youth Self-Report in Greece in a national sample of high school students.

Achenbach's Youth Self Report (YSR) questionnaire is accepted worldwide for the assessment of adolescent competencies and behaviour problems. As with any similar instrument, it is liable to cultural influences, hence requires standardization for the culture in which it is to be used. This study reports on the standardization of the YSR in Greece, in a national school-based sample of 1456 high school students, 11-18 years of age. Responses at the item level seem to follow the culturally expected gender behaviour. Behaviour problem scale scores were not affected by degree of urbanization, reflecting a high degree of cultural homogeneity between urban and rural areas in Greece. Sex effects were important, with girls showing a greater tendency towards Internalizing and boys towards Externalizing Problems. Age effects were also statistically significant (older adolescents showing more problems, especially of the delinquent type), but numerically small. There was considerable correlation between Internalizing and Externalizing problems, with an odds ratio of 6.9 (95% confidence interval, 4.6-10.4) for exceeding both cut-offs. The analysis showed that Greek adolescents obtained significantly higher mean scores than their American counterparts on all scales. Cut-off points based on the 90th and 98th percentile developed from this sample are presented for the competencies and the problem scales.

Adolescent↗
PubMed2001

The effects of muscle activation on postural stability in diabetes mellitus patients with cutaneous sensory deficit in the foot.

Activity of the lower leg muscles in response to an unexpected disturbance to upright standing was studied in diabetic patients and non-diabetic matched controls. The diabetic individuals were classified into two groups: diabetic patients with normal cutaneous sensitivity in the foot (n=27) and patients with cutaneous sensory deficit (n=23). All participants completed twenty trials standing on a force platform that rotated upward 8 deg at 50 deg/s. This movement produced short-latency and medium-latency responses in the gastrocnemius muscle and a single long-latency response in the anterior tibialis. All muscle activity was assessed using electromyography techniques. Results indicated that the average delay of the short-, medium- and long-latency responses produced by the diabetic groups was comparable to control group values. However, the within subject variability associated with activating the anterior tibialis was found to be statistically greater for the cutaneous deficit diabetic group. Additionally, fifty percent of the CD group failed to produce an observable stretch reflex response. The results suggest that the inability to generate a neuromuscular response with consistent temporal patterning is a contributing factor to greater postural sway observed in diabetic patients with cutaneous sensory deficit in the foot.

Adult↗
PubMed2001

Effect of an enteric-release formulation of naloxone on intestinal transit in volunteers taking codeine.

INTRODUCTION: Constipation is a common side-effect of opioid therapy; in addition to their analgesic effect, opioids reduce intestinal secretion and motility with an increase in whole-gut transit time. Naloxone, a specific opioid antagonist, reverses these effects but may also cause symptoms of opioid withdrawal in patients on long-term therapy. AIM: To use an enteric-release formulation, designed to produce a topical effect in the gut, with minimum systemic effects. METHODS: Naloxone 10 mg b.d. and codeine 30 mg b.d. were used with identical placebo capsules in four sets of studies; 12 male volunteers were given the drugs alone and in combination, with a control study involving double placebo, during each of four study periods. Whole-gut transit time was calculated and compared for each treatment period. RESULTS: Naloxone, both alone and with codeine, significantly shortened the mean whole-gut transit time compared with the control period, respectively, from 53.1 to 42.1 h (P=0.005) and to 40.7 h (P=0.024). Urgency to defecate was reported by two volunteers on naloxone alone and by three on combination therapy. CONCLUSIONS: The results show that the naloxone formulation counteracts the effect of codeine on intestinal transit, suggesting that it may have useful clinical applications.

Administration, Oral↗
PubMed2001

Enteric-release glyceryl trinitrate in active Crohn's disease: a randomized, double-blind, placebo-controlled trial.

BACKGROUND: Mucosal ischaemia may contribute to the pathogenesis of Crohn's disease. Microvascular abnormalities have been found in colonic resection specimens, and mucosal levels of constitutive nitric oxide synthase are reduced. AIM: To assess the efficacy of a novel, enteric-release formulation of the nitric oxide donor, glyceryl trinitrate, aimed at increasing the mucosal circulation and relaxing smooth muscle in the affected bowel. METHODS: The trial was randomized, double-blind and placebo-controlled. Baseline disease activity was assessed by a structured symptom diary, with blood tests and a quality of life assessment. Patients with a Crohn's disease activity index of > or = 150 and < 450 were randomized to receive 12 weeks of either glyceryl trinitrate (initially 6 mg twice daily, increasing to 9 mg twice daily after 6 weeks) or an identical placebo. Assessments were repeated at 6 and 12 weeks. RESULTS: Seventy patients (22 male) entered the study; 34 were given glyceryl trinitrate and 36 placebo. At 12 weeks, there were no differences between the treatment groups in terms of Crohn's disease activity index, pain, stool frequency, inflammatory markers or quality of life scores. CONCLUSIONS: Enteric-release glyceryl trinitrate did not benefit patients with mild to moderately active Crohn's disease. Whilst ischaemia may contribute to the pathogenesis of Crohn's disease, our results fail to provide supportive evidence for this hypothesis.

Administration, Oral↗
PubMed2001

Chronic pain and coping: a proposed role for nurses and nursing models.

AIMS: Activity of living based nurse models such as that proposed by Roper, Logan and Tierney are utilized commonly to rationalize, structure and guide practice. This paper proposes that their use, in the context of chronic pain, should be extended to incorporate the assessment of coping and its effect on disability. BACKGROUND: As coping has been found to account for some of the variance in adaptation to chronic pain, generic models of coping and their utility in this context are considered. The need for reliable and valid means to assess coping are of paramount importance as this will facilitate and inform treatment and management of chronic pain. At the present time coping is most generally assessed using self report instruments which primarily focus on the number and type of strategies used to cope rather than their effectiveness in reducing disability and increasing function. FINDINGS: A classification system which categorizes chronic pain patients in terms of how they function in daily life as either adaptive copers, interpersonally distressed or dysfunctional is outlined. The similarities between this and a routine nursing assessment based on an activities of living model are highlighted. CONCLUSIONS: It is proposed that the innovative use of nursing activity of living models could provide the framework for a pain clinic based assessment of coping that has greater utility for professionals and patients alike.

Activities of Daily Living↗
PubMed2001

Autologous blood donation and transfusion in Europe.

BACKGROUND AND OBJECTIVES: The aim of this study was to record practices in autologous blood transfusion in Europe in 1997. MATERIALS AND METHODS: A questionnaire mainly about predeposit was distributed to the National Representatives of all 41 member states of the Council of Europe's Committee of Experts on Blood Transfusion and Haematology. Replies were received from 29. RESULTS AND CONCLUSION: Autologous blood units collected in 1997 amounted to 4.2% of the allogeneic units, with wide variations between countries. Predeposit was used most frequently in Italy (8.9%), Germany (7.1%) and France (6.6%). Some countries, notably Scandinavia, do not encourage predeposit, chiefly on the grounds that it is not cost-effective, but others are promoting its use.

Blood Banks↗