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R Powell

Publications and source records attributed to R Powell.

At least 37 records · Page 2Linked to original sources
PubMed2000

Sex and relationships following childbirth: a first report from general practice of 131 couples.

Changes in a couple's sexual relationship following childbirth may be more significant than previous studies have suggested. Around 50% of first-time parents in this study described their sex life as 'poor' or 'not very good' eight months after the birth of their baby, and one in five said that they would like help for this. First-time parents rating their general relationship as 'poor' or 'not very good' rose from 1% before pregnancy to 20% eight months after childbirth. Changes in the general relationship and the quality of sex life were associated in these couples.

Coitus↗
PubMed2000

A cost consequence study of the impact of a dermatology-trained practice nurse on the quality of life of primary care patients with eczema and psoriasis.

BACKGROUND: The practice nurse is central to the development of a primary care-led National Health Service. Skin diseases can have a major impact on patients' lives but general practitioners (GPs) lack many of the skills of practical dermatology care and support. AIM: To determine whether a primary care dermatology liaison nurse should be introduced by our health authority. We identified the resources consumed and the benefits that accrued from a practice nurse who had received training in practical dermatology care. METHOD: A cost consequence study in parallel with a randomised controlled trial was undertaken in a group of nine GPs and 109 patients between the ages of 18 and 65 years who had a diagnosis of psoriasis or eczema. RESULTS: Although there was a significant improvement in our primary outcome measure within group, when compared with the control group significance was not achieved. There was no significant change in the Euroqol measure but the clinical instrument showed a significant change when compared with control. On entry, our qualitative data identified three main themes--the embarrassment caused by these skin conditions, the wish for a cure rather than treatment, and concern over the long-term effects of steroids. On completion, 20% of patients expressed that they had received a positive benefit from the clinic. CONCLUSION: This study demonstrates the difficulties of obtaining relevant information to facilitate decisions on how resources should be allocated in primary care. Not all questions can be answered by large multi-centred trials and studies themselves have an opportunity cost consuming resources that could otherwise be spent on direct health care. Often, local resource decisions will be based on partial evidence-yielding solutions that are satisfactory rather than optimum but which are, nevertheless, better than decisions taken with no evidence at all.

Adolescent↗
PubMed2000

Pharmacokinetic/pharmacodynamic modeling in drug research and development.

The two domains in clinical pharmacology dealing with optimizing dosing recommendations are pharmacokinetics and pharmacodynamics. However, the usefulness of these disciplines is limited if viewed in isolation. Pharmacokinetic/pharmacodynamic (PK/PD) relationships and modeling builds the bridge between these two classical disciplines of clinical pharmacology. It links the concentration-time profile as assessed by pharmacokinetics to the intensity of observed response as quantified by pharmacodynamics. Thus, the resulting so-called integrated PK/PD-models allow the description of the complete time course of the desired and/or undesired effects in response to a drug therapy. PK/PD-modeling can elucidate the causative relationship between drug exposure and response and provide a better understanding of the sequence of events that result in the observed drug effect. This information can then be used to streamline the drug development process and dose optimization. This consensus paper presents an update on the current state of PK/PD-modeling from an academic, industrial and regulatory perspective.

Drug Design↗
PubMed1999

Small subunit rRNA gene sequences of Aeromonas salmonicida subsp. smithia and Haemophilus piscium reveal pronounced similarities with A. salmonicida subsp. salmonicida.

The small subunit ribosomal RNA (SSU rRNA) encoding genes from reference strains of Aeromonas salmonicida subsp. smithia and Haemophilus piscium were amplified by polymerase chain reaction and cloned into Escherichia coli cells. Almost the entire SSU rRNA gene sequence (1505 nucleotides) from both organisms was determined. These DNA sequences were compared with those previously described from A. salmonicida subsp. salmonicida, subsp. achromogenes and subsp. masoucida. This genetic analysis revealed that A. salmonicida subsp. smithia and H. piscium showed 99.4 and 99.6% SSU rRNA gene sequence identity, respectively, with A. salmonicida subsp. salmonicida.

Aeromonas↗
PubMed1999

Polymerase chain reaction (PCR)-based typing analysis of atypical isolates of the fish pathogen Aeromonas salmonicida.

Two hundred and five isolates of atypical Aeromonas salmonicida, recovered from a wide range of hosts and countries were characterized by polymerase chain reaction (PCR) targeting four genes. The chosen genes were those encoding the extracellular A-layer protein (AP), the serine protease (Sprot), the glycerophospholipid:cholestrol acetyltransferase protein (GCAT), and the 16S rRNA (16S rDNA). All the atypical A. salmonicida isolates could be assigned to 4 PCR groups. Group 1 comprised 45 strains which tested positive for PCR amplification, using the 16S rDNA, GCAT2, Sprot2, and AP primer-sets. Group 2 comprised 88 strains with produced PCR products using the 16S rDNA, GCAT2 and AP primer-sets. Group 3 comprised 21 strains which produced PCR products using 16S rDNA, GCAT2 and Sprot2 primer-sets, and group 4 comprised 51 strains which produced PCR products using the 16S rDNA and GCAT2 primer-sets only. A. salmonicida subsp. salmonicida isolates tested, belonged to group 1. The PCR primer-sets separated A. salmonicida from other reference strains of Aeromonas species and related bacteria with the exception of Aeromonas hydrophila. The results indicated that PCR typing is a useful framework for characterization of the increasing number of isolations of atypical A. salmonicida.

Acyltransferases↗
PubMed1999

Dietary-fat intake in the US population.

OBJECTIVE: This article looks at the food group choices by individuals grouped based on fat intake, saturated fat intake, and use of lowfat foods. METHODS: Food consumption data from USDA's National Food Consumption Surveys (NFCS) and the Continuing Survey of Food Intakes by Individuals (CSFII) were used to look at changes in the mean energy, percent calories from fat and saturated-fat and total-fat intakes over time. USDA's 1995 CSFII data were used to evaluate the diets of individuals grouped based on percent calories from fat and use of low-fat foods. Individuals six to 50 years old who had complete food intake records were included and five age-gender classifications were used. RESULTS: The percent of calories from total fat and saturated fat have steadily declined over the last 30 years, and the amount of fat in the diet has increased from 1989 to 1995. Those whose diets met the Dietary Guidelines Recommendations for fat and saturated fat had lower fat intakes. Except for adult males, those with low-fat diets had higher intakes of total-food amount. Also, lower saturated-fat intakes were associated with lower energy intakes. In general, high-fruit-and-grain-products consumption were seen in groups with low-fat intake. For those who included low-fat foods in their diets and also had low-fat intakes, rice and pasta were the major foods of choice for calories. Fried potatoes were one of the main sources of calories for high-fat groups. CONCLUSION: The study showed individuals whose diets included low-fat foods are more likely to have a diet that meets the dietary guidelines recommendations for fat and saturated fat.

Adolescent↗
PubMed1999

Crystallization and preliminary X-ray diffraction analysis of a biologically active fragment of CD55.

Crystals have been grown of two of the domains of CD55. This is the first report of crystallization of a short consensus repeat (SCR) domain containing protein. CD55 is a widely expressed polymorphic glycoprotein, which functions as a complement regulator by inhibiting assembly and promoting destruction of C3 and C5 convertases. As a key regulator of complement, CD55 is implicated in the hyperacute rejection of xenografts from pigs into primates. It is also commonly hijacked as a receptor by viruses (e.g. medically important echoviruses and coxsackieviruses) and bacterial pathogens (e.g. certain pathogenic strains of Escherichia coli). Here, crystallization of a virus-binding fragment expressed in yeast, consisting of two of the four extracellular SCR domains of CD55, is reported. The recombinant domains have been crystallized in 30% polyethylene glycol (PEG), 0.2 M sodium acetate, 0.1 M sodium acetate trihydrate pH 4.6 using the sitting-drop vapour-diffusion method. Two crystal forms are observed (orthorhombic and monoclinic) and a native data set to 1.65 A resolution has been collected from the monoclinic form at the Synchrotron Radiation Source, Daresbury, UK.

CD55 Antigens↗
PubMed1999

Transport and temperature effects on measurement of serum and plasma potassium.

Transport of blood samples from general practice to a central laboratory can result in spuriously high or low potassium concentrations. The importance of this phenomenon was studied in a general practice serving a population of 15,000 patients, 27 km from the pathology laboratory that routinely measured serum potassium. The design involved comparison of potassium levels between control serum (plain gel-separation serum tubes centrifuged in the surgery), routine serum (plain gel-separation tubes centrifuged in the laboratory) and routine plasma samples (lithium-heparin tubes centrifuged in the laboratory). Complete triple sets of data were obtained for 371 samples. Altman and Bland plots for the control serum vs routine serum samples showed a mean difference of +0.1 mmol/L with limits of agreement (+/- 2SD) +0.6 mmol/L, -0.4 mmol/L and for control serum vs routine plasma a mean difference of +0.2 mmol/L with limits of agreement +0.8 mmol/L, -0.4 mmol/L. There was a negative association between mean weekly routine plasma potassium levels with mean weekly temperatures achieved. Regression analysis indicated that both maximum temperature achieved and time to centrifugation significantly contributed to differences observed in the routine plasma samples, but not with the routine serum samples. For plasma samples exposed to high temperatures a clinically significant lowering of potassium concentrations can arise. These results confirm that spurious lowering of potassium concentrations occurs in plasma samples collected in a primary care setting. The preferred method is to centrifuge samples soon after venepuncture. Where this is not possible, collection into plain gel-separation tubes (serum) ensures less variation due to temperature and time to centrifugation than does collection into lithium-heparin tubes (plasma).

Blood Preservation↗
PubMed1998

Convergence of progesterone with growth factor and cytokine signaling in breast cancer. Progesterone receptors regulate signal transducers and activators of transcription expression and activity.

STATS (signal transducers and activators of transcription) are latent transcription factors activated in the cytoplasm by diverse cell surface signaling molecules. Like progesterone receptors (PR), Stat5a and 5b are required for normal mammary gland growth and differentiation. These two proteins are up-regulated during pregnancy, a period dominated by high levels of progesterone. We now show that progestin treatment of breast cancer cells regulates Stat5a and 5b, Stat3, and Stat1 protein levels in a PR-dependent manner. In addition, progestin treatment induces translocation of Stat5 into the nucleus, possibly mediated by the association of PR and Stat5. Last, progesterone pretreatment enhances the phosphorylation of Stat5 on tyrosine 694 induced by epidermal growth factor. Functional data show that progestin pretreatment of breast cancer cells enhances the ability of prolactin to stimulate the transcriptional activity of Stat5 on a beta-casein promoter. Progesterone and epidermal growth factor synergize to control transcription from p21(WAF1) and c-fos promoters. These data demonstrate the convergence of progesterone and growth factor/cytokine signaling pathways at multiple levels, and suggest a mechanism for coordination of PR and Stat5-mediated proliferative and differentiative events in the mammary gland.

Biological Transport↗
PubMed1998

Characterization of atypical Aeromonas salmonicida by different methods.

Fifty two isolates of atypical Aeromonas salmonicida, recovered from a wide range of hosts and geographical locations, were heterogeneous in terms of molecular and phenotypic characteristics, and represented taxa which could not be accommodated by the current classification of four subspecies. Generally, there was incongruence between the molecular (PCR, RAPD and ribotyping) and phenotypic methods in terms of cluster membership. By PCR, 6 groups were described of which Group 1 encompassed 12 isolates including the type strain of A. salmonicida subsp. smithia. Group 2 accommodated 23 isolates including the reference cultures of subspecies achromogenes and masoucida. The named culture of Haemophilus piscium was recovered in Group 6. By ribotyping and RAPD, the reference cultures were recovered in separate groups. All methods pointed to the uniqueness of subspecies smithia. Most isolates contained 2-6 plasmids, of 2.3 to 150 kb in length. Nevertheless, all isolates possessed certain key characteristics, including Gram-negativity, and the absence of motility.

Aeromonas↗
PubMed1997

Current approaches to identifying the severely mentally ill.

Mental health care is expensive to provide and resources should be targeted. Possible approaches to such a prioritization are outlined. In the United Kingdom, care is to be provided on the basis of need. The key issue is then identifying the severely mentally ill, who are most in need of mental health care. Definitions of severe mental illness used in research studies are reviewed, indicating a lack of consensus about identifying this group. Current practice in England was surveyed, by obtaining written documentation from 20 agencies on the eligibility criteria they use for deciding whether someone should receive mental health care. Government departments, user groups and professional bodies were also surveyed. The findings indicate that definitions of severe mental illness use the five dimensions of safety, informal and formal support, diagnosis, disability and duration--the SIDDD dimensions. These dimensions offer a framework for developing definitions of severe mental illness at the local level, thereby identifying the priority group for mental health care.

Cost of Illness↗
PubMed1997

Immunohistochemical detection of p53 and c-erbB-2 in oesophageal carcinoma; no correlation with prognosis.

TNM staging of oesophageal cancer provides significant prognostic information but its clinical impact is limited as many patients present with advanced disease (i.e. T3N1). Additional prognostic markers may help separate those with 'good' and 'bad' prognosis tumours and so help with decisions such as selection for adjuvant therapy. p53 and c-erbB-2 overexpression may correlate with poor prognosis in oesophageal cancer, but this is uncertain. This study aimed to investigate the value of these biomarkers as prognostic indicators in resected oesophageal cancer. Two hundred and five oesophageal tumours (127 adenocarcinoma, 78 squamous) resected by a single surgeon between June 1979 and January 1991 were investigated for p53 and c-erbB-2 overexpression using DO-7 and CB-11 immunohistochemistry. Patient survival was analysed by Kaplan-Meir life tables. Median survival was 61 weeks (range: 5-747) and survival diminished significantly with increasing UICC stage (P < 0.0001). Sixty-eight per cent of squamous tumours and 66% of adenocarcinomas overexpressed p53 but there was no statistically significant correlation with prognosis. Twenty-six per cent of squamous tumours and 23% of adenocarcinomas overexpressed c-erbB-2, but again this did not correlate with survival. p53 and c-erbB-2 are commonly overexpressed in oesophageal cancer but do not appear to be related to prognosis in this large series of resected oesophageal cancers and other candidate biomarkers must be sought.

Adenocarcinoma↗
PubMed1997

Validation of current practice and a near patient testing method for oral-anticoagulant control in general practice.

When oral anticoagulant control is monitored in general practice, venous blood samples are usually transported to a central laboratory for determination of international normalized ratio (INR). An alternative is near patient testing by a commercial method. In a rural general practice 27 km from a central haematology laboratory, whole blood samples were drawn from patients receiving oral anticoagulants and analysed by three methods: after centrifugation, plasma separated and frozen in liquid nitrogen, transported to the laboratory, thawed and immediately analysed (control); courier transport of citrated sample to the laboratory for analysis (routine); near patient testing of whole blood sample (NPT). Maximum temperature achieved and time to analysis for routine samples were recorded. 306 complete sets of data were obtained. Comparison between the routine method and the control method revealed acceptable agreement. On multiple regression analysis, maximum temperature achieved did not contribute to differences observed but time to analysis of over 5 hours did make a significant contribution. Comparison between the NPT method and control method showed acceptable agreement, with persistent under-recording by the NPT method. The routine method for INR determination was validated as robust and reproducible with the proviso that needle-to-analysis time should be kept below 5 hours. The NPT method was valid under conditions of normal general practice. Strict quality control of NPT methods is essential if performance is to be comparable with that of established methods.

Anticoagulants↗
PubMed1997

Changing eating patterns of American children: a view from 1996.

A major diet-related problem in the US has changed from growth retardation to childhood obesity. This paper compares the consumption patterns of children using data from nationally representative surveys conducted by the US Department of Agriculture from 1986 to 1994. Children's consumption patterns were analyzed by age groups, income groups and food security levels. From 1986 to 1994, no distinct trends of the energy intakes of children 5 years of age and under were observed. In 1994, a greater percentage of children were meeting the dietary guidelines for fat and saturated fat than in 1989-91. However, most of the children's diet in each sex/age category still exceeds the dietary guideline's recommendations.

Adolescent↗
PubMed1996

Cloning, characterization and chromosomal location of a satellite DNA from the Pacific oyster, Crassostrea gigas.

We report the cloning and characterization of a high-copy-number, tandem-repeat satellite DNA sequence from the genome of the Pacific oyster, Crassostrea gigas (Cg). The monomeric unit was found to be 166 (+/- 2) bp in length with 79-94% homology between monomers of the array. The sequence is A+T-rich (60%) and lacks internal repetition and substructural features. The repeat was estimated to account for 1-4% of the Cg genome. Fluorescence in situ hybridization (FISH) studies mapped the repeat to two distinct heterochromatic regions of two pairs of homologous chromosomes on Cg embryonic metaphases. Also, the number of metaphase chromosomes containing this repeat varied with the ploidy of the cell.

Animals↗