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Biomedical subjects

P Newton

Publications and source records attributed to P Newton.

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

Think before you speak: pauses, memory search, and trace redintegration processes in verbal memory span.

Immediate memory span and speed of memory search were assessed for words and nonwords of short and long spoken duration. Memory span was substantially greater for words than for nonwords and for short than for long items, though speed of memory search was unaffected by either length or lexicality. An analysis of the temporal pattern of responses in the memory span task indicated that inter-item pauses were longer between nonwords than words but that these pause durations were unaffected by item length. A model of verbal short-term memory span is described in which trace selection from a short-term store and the redintegration (restoration) of degraded phonological traces both occur in the pauses between saying successive items. Both trace selection and trace redintegration appear to play important roles in accounting for individual differences in memory span.

Adolescent↗
PubMed1999

The presentation and management of female breast symptoms in general practice in Sheffield.

BACKGROUND: Relatively little is known about the incidence of breast symptoms in primary care consultations and GPs' patterns of referral to secondary care. OBJECTIVE: We aimed to identify the consultation rate for breast symptoms in general practice and to describe the management of those symptoms, including patterns of referral to secondary care. METHOD: Prospective data were collected by 248 GPs concerning 508 women consulting for breast symptoms. A verification study was carried out in nine practices to compare the data collected prospectively with information recorded contemporaneously in the same patients' notes. Main outcome measures were number of patients with lump, pain, nipple discharge, skin or nipple problems, family history or other symptoms at first or subsequent consultation, management action, age of patient and number of patients meeting study criteria for whom GPs did not record information in the prospective study. RESULTS: The mean number of consultations per GP over the 4-week recording period was 2.05. However, examination of a patient's notes from a sample of nine practices participating in the verification study suggested that GPs recorded only slightly over half of the consultations for breast symptoms on the study pro forma. At their first consultation, 40% of women presented with a breast lump and 40% with breast pain. Fifty-eight per cent of women with lumps were referred for specialist evaluation after a first or subsequent consultation, whereas the comparable percentage for women referred for pain was 17%. CONCLUSIONS: At an initial consultation for breast symptoms, GPs refer approximately one-third of women to secondary care. Women are most likely to be referred for a lump or for a family history of breast cancer and least likely to be referred for breast pain. The verification study suggests that relying on GPs to collect data on a specific group of patients may produce an underestimate of the consultation rates for a specified condition.

Adolescent↗
PubMed1999

Chronic inhalation carcinogenicity study of commercial hexane solvent in F-344 rats and B6C3F1 mice.

The carcinogenic and chronic toxicity potential of commercial hexane solvent was evaluated in F-344 rats and B6C3F1 mice (50/sex/concentration/species) exposed by inhalation for 6 h/day, 5 days/week for 2 years. Target hexane vapor concentrations were 0, 900, 3000, and 9000 ppm. There were no significant differences in survivorship between control and hexane-exposed groups, and clinical observations were generally unremarkable. Small, but statistically significant decreases in body weight gain were seen in rats of both sexes in the mid- and high-exposure groups and in high-expsoure female mice. The only noteworthy histopathological finding in rats was epithelial cell hyperplasia in the nasoturbinates and larynx of exposed groups. This response was judged to be indicative of upper respiratory tract tissue irritation. No significant differences in tumor incidence between control and hexane-exposed rats were found. In mice, uterine tissue from the high-exposure females exhibited a significant decrease in the severity of cystic endometrial hyperplasia compared to controls. An increase in the combined incidence of hepatocellular adenomas and carcinomas was observed in high-exposure female mice. The incidence of liver tumors was not increased in the mid- or low-exposure female mice or in male mice exposed to hexane. An increased incidence of pituitary adenomas was observed in female, but not male mice. This finding was not believed to have been treatment-related because the incidence in the control group was unusually low, and the incidence in exposed groups was not dose-related and was within the historical control range. No other neoplastic changes judged to be treatment-related were observed in tissues from male or female mice. In conclusion, chronic exposure to commercial hexane solvent at concentrations up to 9000 ppm was not carcinogenic to F-344 rats or to male B6C3F1 mice, but did result in an increased incidence of liver tumors in female mice.

Adenoma, Liver Cell↗
PubMed1999

Malaria: new developments in treatment and prevention.

Malaria still kills some 0.5-2.5 million people per year in the tropics. Resistance to the cheap, most commonly used antimalarials continues to spread alarmingly and could outpace drug development. The artemisinin derivatives have had an important clinical impact both on the treatment of resistant falciparum malaria and on the incidence of disease in low-transmission areas. A few promising new antimalarials are being tested clinically but there is an imperative need for cheap, well-tolerated drugs that can be used in short courses, and for strategies to delay the onset of drug resistance. Bed nets have been shown to reduce the incidence of severe malaria in many areas but an effective vaccine is urgently needed.

Antimalarials↗
PubMed1998

Well-being and treatment satisfaction in older people with diabetes.

OBJECTIVE: To measure well-being and treatment satisfaction and their correlates in older people with diabetes. RESEARCH DESIGN AND METHODS: A postal survey was conducted of 1,000 diabetic patients aged > or = 60 years, representing 56% of the resident older diabetic population in an inner-city health district with a largely indigenous population of 230,000 people and a widely varied socioeconomic mix. Well-being and treatment satisfaction were measured with diabetes-specific instruments and correlated with patient data held in a central register. RESULTS: There was an 81% response. The general well-being scores (median [interquartile range]) for patients on diet alone, tablets, and insulin were 54 (44-60), 53 (42-61), and 48 (35-56) (P < 0.001 comparing insulin with diet and tablets) compared with a scale maximum of 66. Treatment satisfaction scores were 35 (31-36), 35 (32-36), and 34 (30-36) (P < 0.001 comparing insulin with diet and tablets), scale maximum 36. Mean HbA1c concentrations were 5.0 +/- 1.4% (for patients on diet alone), 5.8 +/- 1.6% (tablets), and 6.6 +/- 1.7% (insulin) (P < 0.001 for each difference). Neither well-being nor treatment satisfaction correlated with HbA1c. Insulin-treated patients were younger and had been diabetic longer than non-insulin-treated patients; their well-being remained slightly, but significantly, lower when adjusted for age, sex, BMI, and diabetes duration, but treatment satisfaction was no longer significantly different. Women had lower well-being than men. CONCLUSIONS: It has proved possible to measure well-being and treatment satisfaction in a large community-based samples of older people with diabetes. At the level of glycemic control in this population, neither parameter correlated with HbA1c. The lower well-being in insulin-treated patients remained significant in multivariate analysis.

Aged↗
PubMed1997

Long-term follow-up in outpatient clinics. 1: The view from general practice.

BACKGROUND: Nearly three-quarters of patients seen in specialist outpatient clinics in England are in follow-up. It has been suggested that the care of many of these patients could be transferred to general practice. OBJECTIVES: We aimed to estimate the proportion of patients in general practice who are in long-term outpatient follow-up, and to identify GPs' perspectives on the appropriateness and implications of the discharge of their patients to primary care. METHOD: Prevalence data were collected by identifying correspondence from outpatient clinics to GPs in four Manchester practices (population 29,000). GPs were asked to assess the suitability for discharge of their patients who were seen in medical outpatient clinics. Semi-structured interviews were carried out with 15 of these GPs, and with 11 GPs who had patients recently discharged from medical clinics. RESULTS: At least 4.5% of the practice populations were in long-term outpatient follow-up (median duration 25 months). These patients had consulted their GP a median of seven times during the previous year. GPs were willing to take over the care of 48% of patients in medical clinics, and in many cases did not expect that this would lead to an increase in their workload. Some resource needs were identified in general practice, and improvements to the process of discharge were suggested. CONCLUSION: The need for continued follow-up in outpatient clinics should be reviewed. Many patients could be discharged without increasing GPs' workload. For more complex cases, additional resources may be needed to provide co-ordinated care within general practice. When patients are discharged, GPs need information quickly and need access to specialist advice for their patients when necessary without long delays.

Ambulatory Care Facilities↗
PubMed1997

Bovine surfactant therapy for patients with acute respiratory distress syndrome.

Lung surfactant is deficient in patients with acute respiratory distress syndrome (ARDS). We performed a randomized, prospective, controlled, open-label clinical study of administration of a bovine surfactant to patients with ARDS to obtain preliminary information about its safety and efficacy. Patients received either surfactant by endotracheal instillation in addition to standard therapy or standard therapy only. Three different groups of patients receiving surfactant were studied: patients receiving up to eight doses of 50 mg phospholipids/kg, those receiving up to eight doses of 100 mg phospholipids/kg, and those receiving up to four doses of 100 mg phospholipids/kg. Outcome measures included ventilatory support parameters, arterial blood gases, organ system failures, bronchoalveolar lavage (BAL) analyses, immunologic analyses, survival, and adverse events during the 28-d study period. Fifty-nine study patients were evaluable; 43 in the surfactant group and 16 in the control group. The FI(O2) at 120 h after treatment began was significantly decreased only for patients who received up to four doses of 100 mg phospholipids/kg surfactant as compared with control patients (p = 0.011). Mortality in the same group of patients was 18.8%, as compared with 43.8% in the control group (p = 0.075). The surfactant instillation was generally well tolerated, and no safety concerns were identified. This pilot study presents preliminary evidence that surfactant might have therapeutic benefit for patients with ARDS, and provides rationale for further clinical study of this agent.

Adult↗
PubMed1996

Psittacosis associated with bilateral 4th cranial nerve palsies.

We report a 55-year-old man who presented with a moderately severe community acquired pneumonia due to Chlamydia psittaci, probably acquired from budgerigars. One of his presenting symptoms was diplopia, secondary to bilateral 4th cranial nerve palsies, which persisted for some months. The literature on neurological complications of pneumonia is reviewed.

Chlamydophila psittaci↗
PubMed1995

Fluctuations in nucleus accumbens dopamine concentration during intravenous cocaine self-administration in rats.

Fluctuations in extracellular dopamine and DOPAC levels in nucleus accumbens septi (NAS) were monitored in 1-min microdialysis samples taken from rats engaged in intravenous cocaine self-administration. For four rats the dose per injection was fixed at 2.0 mg/kg; for four others the dose per injection was varied irregularly, from one response to the next, between three levels (0.5, 1.0 and 2.0 mg/kg). Regardless of the dosing regimen, extracellular dopamine levels were tonically elevated by 200-800% within the cocaine self-administration periods, fluctuating phasically within this range between responses. In the fixed dose condition, the phasic increases following each injection (and the phasic decreases preceding them) averaged approximately 50% of the mean tonic elevation. Phasic fluctuations in dopamine levels remained time-locked to lever-presses even when response rate was irregular, because of the variable dose condition. In the variable dose condition greater increases in dopamine and longer inter-response times followed injections of the higher doses; dopamine fluctuations were consistent with the multiple-infusion pharmacokinetics of cocaine. DOPAC levels showed a slow tonic depression during cocaine self-administration, but individual injections were not associated with discernible phasic fluctuations of DOPAC. These data are consistent with the hypothesis that falling dopamine levels trigger successive responses in the intravenous cocaine self-administration paradigm, but inconsistent with the notion that extracellular dopamine levels are depleted at the times within sessions when the animal initiates drug-seeking responses.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1995

Referrals between specialists in hospital outpatient departments.

There is little information on referrals between consultants (cross-referrals), and they are difficult to identify within current information systems which may affect the development of efficient services, and erode the traditional role of the general practitioner (GP) as the gatekeeper to secondary care. For one month in 1994, the source and outcome for all outpatient attendances was recorded in medical, paediatric and orthopaedic clinics in a teaching hospital and in a district general hospital. Detailed interviews were also held with consultants to increase understanding of reasons for cross-referral, and their appropriateness. Referrals from hospital doctors were more frequent in the teaching hospital and in the more specialised clinics. Cross-referral as an outcome of a clinic attendance was more common in the teaching hospital, and among patients seen in the general clinics. These findings support the view that cross-referrals are likely to increase as specialisation among consultants increases. Interviews with consultants showed that they did not believe that there was a need to reduce cross-referrals, which were regarded as an integral part of an effective service for patients. However, the development of GP fundholding may impose new constraints on specialists' ability to refer within the hospital system.

Data Collection↗
PubMed1994

Analysing general practitioners' referral decisions. I. Developing an analytical framework.

Despite a large volume of research, understanding the influences on general practitioner referral behaviour remains limited. This paper argues for the value of an approach to this area based on the analysis of individual referral decisions, rather than aggregated referral statistics. A framework for analysing referral decisions is described, developed from a study that collected accounts of 167 referral decisions from 28 general practitioners. The framework enables referral decisions to be examined at three levels of analysis of increasing generality. It also encompasses factors that influence general practitioners against making a referral as well as those that influence them towards referral, as it was found that both types of influence can be discerned in most cases. The types of study in which the framework would be a useful analytical tool are discussed.

Adolescent↗
PubMed1994

Analysing general practitioners' referral decisions. II. Applying the analytical framework: do high and low referrers differ in factors influencing their referral decisions?

An analytical framework of the referral decision was applied to the question of whether general practitioners (GPs) with relatively high and relatively low referral rates differed in the types of factors that influenced their referral decisions. Interview data from six high referring and six low referring GPs were compared at all levels of the framework, using both quantitative and qualitative content analysis. High referrers were found to mention significantly more negative factors than low referrers, i.e. they referred 'in spite of' reasons against referral. In particular, they referred patients in spite of having doubts about treatment effectiveness. Low referrers mentioned factors related to interpersonal processes significantly more often than high referrers, for example, GP-patient communication as an influence. Possible interpretations of these findings are discussed.

Adolescent↗
PubMed1993

Induced hemichrome formation of methemoglobins A, S and F by fatty acids, alkyl ureas and urea.

1. Spectral analysis of the Soret region (450-350 nm) has shown that saturated fatty acids, alkyl ureas and urea induce the conversion of methemoglobins A, S, and F to the hemichrome state. 2. In the presence of fatty acids (C8-C16), methemoglobin F is converted to the hemichrome state more readily than either methemoglobins A or S. 3. Using several alkyl ureas (methyl, ethyl, propyl, butyl), the extent of hemichrome formation was as follows: met Hb F > met Hb S > met Hb A. The ability of these compounds to induce hemichrome formation is related to their increasing hydrophobicity. 4. Conversion to the hemichrome state in the presence of urea (5M) led to the formation of molecular aggregates of hemoglobins S, F and A which may be initiated by subunit dissociation and conformational changes, coupled to increased globin-globin interactions. 5. Similar aggregation occurred for methemoglobin S in the presence of octanoic acid; no significant aggregation was evident for methemoglobin A after 10 hr of exposure to octanoic acid.

Chromatography, Gel↗