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Biomedical subjects

P Pearson

Publications and source records attributed to P Pearson.

At least 19 recordsLinked to original sources
PubMed1998

Effects of moderate blood alcohol concentrations on spatial and temporal contrast sensitivity.

OBJECTIVE: In order to gain a more complete picture of the influence of alcohol on visual performance, we measured contrast sensitivity for a range of spatial and temporal frequencies in individuals with moderate blood alcohol concentrations (BACs). METHOD: Subjects were tested at blood alcohol concentrations of 0.06% in both the rising and falling phases of absorption. In the first part of the study, the performance of two men and four women on a number of simple screening measures and static contrast sensitivity was measured. In the second part (four men and three women), the grating patterns were contrast reversed at four different rates, allowing us to assess the effects of alcohol on temporal processing. The second study examined the relationship between blood alcohol concentrations and contrast sensitivity. RESULTS: Although few significant changes in performance were found on the simple screening tests, we observed a significant reduction (43%) in stationary contrast sensitivity at the 0.06% BAC. This change in performance was greater at low and high spatial frequencies than at moderate ones. At high temporal frequencies, the reduction in sensitivity was 2.5 times that seen for lower temporal frequencies. With higher blood alcohol concentrations, the decrease in performance was found to be greatest for the high and low spatial frequencies. CONCLUSIONS: These data suggest that alcohol produces visual deficits that are not attributable to pursuit eye movements. It is suggested that these visual deficits, combined with changes in ocular-motor control and attentional deficits, may have a strong effect on performance under the influence of alcohol.

Adult↗
PubMed1997

The vexed question of authorship: views of researchers in a British medical faculty.

OBJECTIVE: To assess knowledge, views, and behaviour of researchers on criteria for authorship and causes and control of gift authorship. DESIGN: Interview survey of stratified sample of researchers. SETTING: University medical faculty. SUBJECTS: 66 staff (94% response rate) comprising several levels of university academic and research appointments. MAIN OUTCOME MEASURES: Awareness and use of criteria for authorship, views on which contributions to research merit authorship, perceptions about gift authorship and strategies for reducing it, and experiences of authorship problems. RESULTS: 50 (76%) respondents supported criteria for authorship, but few knew about or used available criteria. Of the five people who could specify all three criteria of the International Committee of Medical Journal Editors, only one knew that all criteria had to be met. Forty one respondents (62%) disagreed with this stipulation. A range of practical and academic contributions were seen as sufficient for authorship. Gift authorship was perceived as common, promoted by pressure to publish, to motivate research teams, and to maintain working relationships. A signed statement justifying authorship and a published statement of the contribution of each author were perceived as practical ways of tackling gift authorship. Most researchers had experienced problems with authorship, most commonly the perception that authorship had been deserved but not awarded (49%). CONCLUSION: There seems to be a gap between editors' criteria for authorship and researchers' practice. Lack of awareness of criteria is only a partial explanation. Researchers give more weight than editors to practical research contributions. Future criteria should be agreed by researchers and not be imposed by editors.

Attitude↗
PubMed1997

Primary care--opportunities and threats. Developing professional knowledge: making primary care education and research more relevant.

The trio of recent government white papers heralds a new world for primary care. Many changes in the education of future primary health care professionals and in the research ethos of the discipline will be needed to realise this vision. New skills and attitudes, not least in multidisciplinary working; lifelong learning; and greater understanding of and participation in primary care research will have to emerge from educational efforts in the next few years.

Education, Medical, Continuing↗
PubMed1997

Early supported hospital discharge following acute stroke: pilot study results.

OBJECTIVE: To establish the feasibility and method of evaluation of an early supported hospital discharge policy for patients with acute stroke. DESIGN: A randomized controlled trial comparing an early supported discharge service to conventional care. SETTING: Three acute hospitals in Newcastle upon Tyne. SUBJECTS: Ninety-two eligible patients with acute stroke admitted between 1 February 1995 and 31 January 1996. MAIN OUTCOME MEASURES: Placement, length of stay, readmission rates, mortality, functional ability (Nottingham Extended Activities of Daily Living (ADL) Scale), handicap (Oxford Handicap Scale), global health status (Dartmouth Coop Function Charts) and carer stress (General Health Questionnaire 30 item). RESULTS: The median length of stay for patients randomized to early supported discharge was 13 days compared to 22 days in the conventional care group (p = 0.02). The median Barthel ADL index at seven days post stroke of patients randomized to early supported discharge was 15, and 13 for those randomized to conventional care (NS). At three months post stroke the median Nottingham EADL score of patients randomized to early supported discharge was 10 compared to 7 for those who received conventional care (NS). There were no statistically significant differences in the global health status of patients or carer stress. CONCLUSION: An early supported discharge service following acute stroke with individualized rehabilitation in the community is feasible and can be evaluated by a randomized controlled trial but a larger multicentre trial is needed before such a service is widely adopted.

Activities of Daily Living↗
PubMed1996

Localized cisplatin hyperpigmentation induced by pressure. A case report.

BACKGROUND: The spectrum of side effects induced by chemotherapy includes skin hyperpigmentation. This is prone to occur following treatment with alkylating agents and doxorubicin. More recently, hyperpigmentation was discovered in patients treated exclusively with intra-arterial cisplatin and was likely to develop over the dorsal surfaces of the hands and feet, elbows and knees, and operative incisions (trauma). METHODS: We followed the clinical course of a patient with osteosarcoma treated with intravenous (i.v.) cisplatin, doxorubicin, and high-dose methotrexate. RESULTS: Following two courses of chemotherapy, hyperpigmentation developed along the sides of the thorax juxtaposed to the rubber shoulder pads of the patient's crutches. It appeared that the pigmentary change was due to localized pressure in the skin of the patient exposed to i.v. cisplatin. CONCLUSIONS: Factors associated with skin hyperpigmentation as a complication of chemotherapy are discussed. We believe that cisplatin was the major contributing factor. The mechanism for cisplatin-induced hyperpigmentation is undetermined. However, it has occurred in patients treated exclusively with intra-arterial cisplatin and can possibly be attributed to an effect on the melanocytes. / This is supported by experiences in which cisplatin extravasated into the tissues and resulted in a similar phenomenon. Reasons for excluding doxorubicin and methotrexate as causative agents are presented.

Adolescent↗
PubMed1996

Ifosfamide tolerance in osteosarcoma patients previously treated with cis-diamminedichloroplatinum-II: renal, hematologic, and neurologic observations.

We attempted to ascertain renal, hematologic, and neurologic tolerance to ifosfamide (IFX) in pediatric patients previously treated with large single and cumulative doses of cis-Diamminedichloroplatinum-II (CDP) for osteosarcoma (OS). Twenty OS patients were treated with CDP: initially 150 mg/m2 was administered every 2 weeks for a maximum of seven courses. Later, other agents, including additional CDP, were also administered. Twelve patients were treated with intra-arterial CDP, one with intra-arterial, and later intravenous CDP, and seven with intravenous CDP. Patients who relapsed were treated with IFX. Renal function was monitored by measuring creatinine clearance, serum electrolytes, total protein, albumin and CO2 content, and urine analysis during IFX therapy. Prior to initiation of IFX, creatinine clearance was above 60 ml/min/m2 in all except one patient who had developed a hemolytic uremic syndrome (HUS). Cumulative CDP doses ranged from 300 to 22,500 mg/m2, and cumulative IFX doses 12 to 128 gm/m2. Myelosuppression was monitored by obtaining routine hemograms midway between each course of treatment. Neurologic tolerance was assessed by reviewing the medical records for any abnormality. The interval between CDP and IFX ranged from 1 to 64 months. All patients experienced a progressive reduction in creatinine clearance with CDP. The reduction in creatinine clearance, measured from base-line after three to four courses varied from 10 to 53.7%, after four to seven courses from 19 to 78%, and after seven courses from 12 to 80.5%. In all patients except five, including the HUS patient, creatinine clearance remained above 60 ml/min/m2 during IFX therapy. Twelve patients developed hypo-magnesemia in the vicinity of 1.4 to 1.6 mg/dl during CDP treatment and required magnesium supplementation. They were asymptomatic and the abnormality did not affect IFX tolerance. Fourteen patients intermittently displayed variable degrees of glycosuria, phosphaturia, and/or proteinuria during IFX therapy. This was considered to be a forma frustre type of Fanconi's syndrome. Approximately 80% of courses of IFX were associated with reversible myelosuppression. No neurologic abnormalities were detected. The abnormalities detected during IFX treatment were not major, did not give rise to symptomatology, and did not require discontinuation of therapy. Renal abnormalities were considered a forma frustre type of Fanconi's syndrome. Provided a creatinine clearance of 60 ml/min/m2 is accepted as a prerequisite for treatment, and no major preexisting renal disease is present, IFX is well tolerated by most patients previously exposed to very high cumulative doses of CDP.

Adolescent↗
PubMed1996

Texture segmentation along the horizontal meridian: nonmonotonic changes in performance with eccentricity.

In 3 experiments, subjects were required to detect the presence of a small region of disparate texture embedded in a larger background at a range of eccentricities. Detection performance always peaked several degrees from fixation. Experiment 1 showed that the location of the peak was not retinally specific; scaling the display changed the location of the performance peak. Experiment 2 showed that poor foveal performance could not be explained by cross-frequency interference; filtering out high spatial frequencies did not lead to improved foveal performance. Experiment 3 showed that the effect is not unique to textures comprising left and right oblique line segments. A parsimonious account of these data is that, at the fovea, there is a mismatch between the scale of the texture and the scale of the mechanisms responsible for encoding texture differences. This mismatch diminishes as the textures are moved further into the periphery.

Attention↗
PubMed1995

Nurse practitioners.

The department of health is keen to explore the potential of the nurse practitioner to substitute some areas of health care for the more expensive medical practitioner. The RCN has developed a specialist course for nurse practitioners. But as yet there is no clear definition of the role or educational status of the nurse practitioner. This professional briefing examines the issues, and suggests that attempts to define a specific nurse practitioner discipline and role limits its potential, and the potential for the development of current community nursing practitioners.

Humans↗
PubMed1994

Cisplatin-associated hemolytic uremic syndrome.

BACKGROUND: Hemolytic uremic syndrome (HUS) is an acquired disorder largely affecting infants and young children. It is characterized by the triad of microangiopathic hemolytic anemia, acute renal failure, and thrombocytopenia. Although its etiology is unknown, viral and bacterial infections, disseminated malignancies in adults, and a variety of chemotherapeutic agents including cisplatin, have been implicated in its occurrence. The association of HUS with chemotherapeutic agents after its detection in a pediatric patient treated with cisplatin is reviewed. METHODS: A 16-year-old male with osteosarcoma was treated with cisplatin as part of a chemotherapy protocol. After the fourth course, his renal function deteriorated and necessitated cessation of cisplatin. Nine months after the initiation of cisplatin, HUS developed. There was no evidence of residual tumor or metastatic disease. He received numerous packed erythrocyte and platelet transfusions for persistent hemolysis and underwent several episodes of hemodialysis. Utilizing this patient as an example, the authors reviewed the incidence of HUS developing subsequent to the use of other chemotherapeutic agents. RESULTS: In the publishing literature, chemotherapy-associated HUS has been described to occur 54 days to 14 months after the initiation of chemotherapeutic regimens. A variety of agents was associated with the phenomenon. CONCLUSION: Hemolytic uremic syndrome may be a complication of cisplatin, as evidenced by the condition that occurred in a 16-year-old patient with osteosarcoma after cisplatin therapy.

Adolescent↗
PubMed1994

The status of online Mendelian inheritance in man (OMIM) medio 1994.

During the last year many changes have been introduced into the system of maintaining OMIM. There are three major components of the reorganization. First, a distributed editorial system was introduced which provides a three-tiered editorial board with senior editors, science writers and subject editors. Second, MIM entries have been restructured to provide separate gene and phenotype information and to organize them into separate catalogs. The restructuring also establishes clearly defined sections for entering new information, converts old entries to the new structure, and establishes a file maintenance and editorial system in SGML format. Third, the entry numbering and naming system has been modified. In addition, the information has been made available through a variety of output media, including books, CD-ROM and online access based on the IRx, WAIS, Gopher and WWW formats.

Books↗
PubMed1994

Measurement of kinetic parameters for urea in end-stage renal disease patients using a two-compartment model.

Urea kinetic modeling depends critically on the parameters of the model used. When urea is removed during hemodialysis, the kinetic model is quite complex. This experiment describes for the first time the use of injected stable isotope-labeled urea to define kinetics in ESRD patients and compares the magnitude of the two urea compartments in these patients with those of control subjects. Such an experimental approach provides the kinetic data in the most direct manner. A gas chromatograph/mass spectrometer-based assay provided quantitation to as little as 0.2 mol% excess urea. The rapidly equilibrating fraction of the two urea compartments is quantified as 41.2% in ESRD patients and 33.4% in controls (P = 0.24). The rest is in a more slowly equilibrating pool. The urea clearances between these two compartments were near 1 L/min for both sets of subjects. The elimination of urea was due to the metabolic removal of the 15N label in both groups of subjects as well as renal elimination in the controls. The nearly threefold larger clearance (Cl) of labeled urea removal in controls (Cl = 74.6 mL/min) than in ESRD patients (Cl = 25.4 mL/min; P = 0.015) shows the extent to which renal clearance is more important than metabolism. These direct analyses of the fractional volumes and intercompartmental clearances for urea agree closely with previous measurements during high-efficiency hemodialysis and indicate that ESRD patients do not differ significantly from control subjects in these parameters.

Adult↗
PubMed1993

Localization of the 70-kDa peroxisomal membrane protein to human 1p21-p22 and mouse 3.

The 70-kDa peroxisomal membrane protein (PXMP1) is a member of the ATP-binding cassette transporter family. In humans, mutations in this gene may be responsible for a subset of patients with Zellweger syndrome, a lethal inborn error of peroxisome assembly. The PXMP1 gene was assigned to human chromosome 1p21-p22 by in situ hybridization and its murine homologue (Pxmp-1) to chromosome 3 by interspecific backcross analysis.

Animals↗
PubMed1993

The isolation of cDNAs from OATL1 at Xp 11.2 using a 480-kb YAC.

Using an ornithine-delta-aminotransferase (OAT) cDNA, we identified five YACs that cover two nonadjacent OAT-related loci in Xp11.2-p11.3, designated OATL1 (distal) and OATL2 (proximal). Because several retinal degenerative disorders map to this region, we used YAC2 (480 kb), which covers the most distal part of OATL1, as a probe to screen a retinal cDNA library. From 8 x 10(4) plaques screened, we isolated 13 clones. Two were OAT cDNAs. The remaining 11 were divided into eight groups by cross-hybridization. Groups 1-4 contain cDNAs that originate from single-copy X-linked genes in YAC2. Each has an open reading frame of > 500 bp and detects one or more transcripts on a Northern blot. The gene for each was sublocalized and ordered in YAC2. The cDNAs in groups 5-8 contained two or more Alu sequences, had no open reading frames, and did not detect transcripts. The cDNAs from groups 1-4 provide expressed sequence tags and identify candidate genes for the genetic disorders that map to this region.

Chromosomes, Fungal↗