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Biomedical subjects

C Selby

Publications and source records attributed to C Selby.

At least 19 recordsLinked to original sources
PubMed1995

Set up and run an objective structured clinical exam.

Objective structured clinical exams are increasingly used as a way of assessing a range of clinical skills at both undergraduate and postgraduate level. To those planning to introduce such assessments, this article provides basic guidance on their development and structure and the personnel required. For those already using the assessments, our article may provide new ideas or be the impetus for an exchange of ideas. For those who are facing such formal assessment as candidates, we hope this article shows the efforts that are made to achieve the necessary structure and objectivity in this type of examination.

Clinical Competence↗
PubMed1995

Death in notified cases of tuberculosis in Edinburgh: 1983-1992.

Between 1983-1992, 730 cases of tuberculosis were notified in the Edinburgh area (population 6 x 10(5)). A review of available records identified 79 deaths (10.9% of all notifications). Thirty-seven patients (5.1%) died in the year following notification, 14 of these (five females, nine males; median age 71 years) due to tuberculosis. Five of these 14 deaths occurred within 7 days of starting chemotherapy and three deaths were due to miliary disease. Of 41 deaths (58%) before notification, 29 (19 females, 10 males; median age 77 years) were due to tuberculosis (autopsy rate 27/29) and 13 of these 29 deaths, all autopsied, were due to cryptic miliary disease. These findings reinforce continuing concerns about failure to diagnose tuberculosis, particularly cryptic miliary disease, in life.

Adult↗
PubMed1992

Changes in neutrophil deformability following in vitro smoke exposure: mechanism and protection.

We have previously demonstrated a reduction in the deformability of neutrophils, exposed to whole particulate cigarette smoke in vitro, by measuring their ability to filter through a micropore membrane with pore dimensions similar to those of the average pulmonary capillary segment. In this study, we exposed neutrophils to the vapor phase of cigarette smoke and investigated the mechanism of the reduction in neutrophil filterability. Although both stimulated neutrophils and smoke-exposed neutrophils demonstrated an increase in filtration pressures, and thus a reduction in cell deformability, compared with control untreated cells, the spontaneous release of the reactive oxygen intermediates hydrogen peroxide and the superoxide anion was depressed following in vitro smoke exposure and there was no shape change to suggest that smoke-exposed cells were activated. The presence of erythrocytes, plasma, or the antioxidants albumin and glutathione prevented the reduction in cell filterability following smoke exposure, suggesting that in vitro smoke exposure, in our system, was mediated by oxidants. Indeed, the increase in filtration pressures, produced by smoke, could be mimicked by the addition of the oxidant hypochlorous acid. The cytoskeletal inhibitors cytochalasin B and D improved the filterability of smoke-exposed cells, suggesting that smoke may change neutrophil deformability through an effect on the actin component of the cytoskeleton. By contrast, colchicine, a specific inhibitor of the microtubules, had no effect. Preincubation with a monoclonal antibody to the CD18 antigen, to block this major neutrophil adhesive glycoprotein, did not alter the filtration pressure developed by stimulated or smoke-exposed neutrophils, suggesting that increased adhesivity was not the mechanism of the increase in filtration pressures observed following smoke exposure.(ABSTRACT TRUNCATED AT 250 WORDS)

Antioxidants↗
PubMed1991

The effects of N-acetylcysteine and glutathione on smoke-induced changes in lung phagocytes and epithelial cells.

We studied the mechanism of the delay in neutrophil traffic in pulmonary microvasculature previously observed during cigarette smoking, the effect of cigarette smoke on lung phagocytes and epithelial cell function, and augmentation of the glutathione (GSH) antioxidant system using the thiol drug N-acetylcysteine. Using a micropore membrane system to mimic the dimensions of the average pulmonary capillary, we showed that cigarette smoke reduces cell deformability, increasing the difficulty experienced by the larger neutrophils in negotiating the smaller capillary segments, so delaying their passage during smoking. This effect is both diminished and recoverable by the addition of plasma, and by GSH in concentrations found in plasma. Cigarette smoke induces oxidative changes in both the cell membrane and the cell cytoskeleton, and diminishes the ability of neutrophils to release reactive oxygen intermediates. The injurious effect of oxidants can be measured in vitro by the detachment of 51Cr-radiolabeled alveolar epithelial cells grown in monolayers, an effect also diminished by the addition of GSH. Such epithelial cell detachment in vitro may be reflected as the epithelial permeability that occurs at an early stage in asymptomatic smokers. N-Acetylcysteine given orally (600 mg/day) increases both plasma and bronchoalveolar lavage GSH in normal subjects, but a sustained increase in plasma GSH requires higher dosage regimens in patients with chronic obstructive pulmonary disease (600 mg three times daily). Thus, the potential exists to enhance the antioxidant status of both plasma and the airspaces of the lungs against oxidant-induced injury.

Acetylcysteine↗
PubMed1991

Course of brittle diabetes: 12 year follow up.

OBJECTIVE: To determine the course of brittle diabetes. DESIGN: 12 year follow up of patients identified in 1977-9 as having brittle diabetes; retrospective review of the case notes. SETTING: Nottingham health district. SUBJECTS: 25 brittle diabetic patients were identified in 1979-9; 11 (five men) had three or more admissions with ketoacidosis between June 1977 and 1979 and 14 (eight men) had three or more attendances at the accident and emergency department with hypoglycaemia in 1978. Two controls from our diabetic register were matched to each patient for age, sex, and duration of diabetes. MAIN OUTCOME MEASURES: Frequency of ketoacidosis and severe hypoglycaemia in the 12 years after ascertainment; diabetic control and complications in 1988-90; retrospective attribution of the cause of brittleness. RESULTS: Patients with recurrent ketoacidosis had had a median (range) of 28 (8-67) episodes. One man died of a cerebral tumour but five of the surviving nine patients had not been admitted in the past two years, although diabetic control remained poor (median haemoglobin A1 concentration 14%). Seven patients had pure hypoglycaemic brittleness, and five had also had eight or more admissions with ketoacidosis (mixed brittleness). Two died of uraemia within a year after ascertainment and two others in hypoglycaemic coma seven and 12 years later. Brittle diabetes was in most cases related to a specific situation, usually unhappiness at home or school. CONCLUSIONS: Brittle diabetes is often episodic and almost always related to stressful life circumstances. Once the underlying cause is removed it tends to improve. Recurrent hypoglycaemic brittleness of psychological origin has a poor prognosis.

Adolescent↗
PubMed1991

Prospective assessment of the role of five tumour markers in breast cancer.

Retrospective analysis previously identified significant elevation of five tumour markers, carcinoembryonic antigen (CEA), ferritin, orosomucoid. C-reactive protein and erythrocyte sedimentation rate (ESR), in patients with systemic breast cancer and showed that changes in each of these markers individually correlated significantly with therapeutic response. In this study we have prospectively tested these findings. None of the five markers was significantly elevated in primary breast cancer compared to normal control or benign breast disease groups. They therefore appear to have no role either in screening or in the differential diagnosis of breast cancer. There was a significant elevation of all five markers in patients with systemic breast cancer (P less than 0.0001: analysis of variance) but sequential changes in CEA and ESR only correlated significantly with the UICC-assessed response. Prospective confirmation of the correlation between changes in serum CEA and ESR provides the basis for using these markers in the assessment of response to therapy in patients with systemic breast cancer.

Adult↗
PubMed1991

Objective measurement of therapeutic response in breast cancer using tumour markers.

In 65 patients with systemic breast cancer, a biochemical response index using three tumour markers in combination, carcinoembryonic antigen (CEA), carbohydrate antigen 15-3 (CA 15-3) and erythrocyte sedimentation rate (ESR), allowed objective biochemical assessment of response to endocrine therapy. Changes in these three markers at 2, 4 and 6 months showed a highly significant correlation with UICC assessed response at 6 months. At 4 months, changes in these three markers resulted in a selectivity of 93%, with a sensitivity of 92% and a specificity of 82%. Survival of groups of patients assessed biochemically or by UICC criteria for non-progression or progression showed no significant difference. The advantage of the biochemical assessment are that it is objective and reproducible. The assessment gives similar information to the UICC assessment but can be carried out earlier. Changes in the three markers appears to reflect the dynamics of change in tumour mass in response to systemic therapy in contrast to the UICC criteria which reflect structural change.

Adolescent↗
PubMed1991

The short Synacthen test in acute hospital admissions.

OBJECTIVE: We wished to define the cortisol response to 250 micrograms intramuscular tetracosactrin (Synacthen) in acute hospital admissions, using a modern immunoassay for cortisol. DESIGN: We performed a prospective study of, as near as possible, a consecutive series of 161 admissions to a single unit. PATIENTS: We studied 50 patients (age range 67-98, mean 80.3 years, 31-female, 19-male) admitted as an emergency, from whom it was possible to obtain informed consent, and whom it was possible to study within 24 hours of admission. MEASUREMENTS: We measured baseline, increment and peak serum cortisol following administration of 250 micrograms intramuscular tetracosactrin between 0800 and 0900 hours. RESULTS: Baseline cortisol concentrations ranged from 288 to 1585 nmol/l (mean 706; median 665). Peak cortisol concentrations ranged from 602 to 2265 nmol/l (mean 1076; median 999). Baseline and peak cortisol concentrations showed a significant correlation (P less than 0.001). Increment varied from 10 to 747 nmol/l (mean 374; median 336) and did not correlate with baseline. CONCLUSIONS: In acute hospital admissions, baseline serum cortisol between 0800 and 0900 hours should exceed 250 nmol/l. Peak serum cortisol after 250 micrograms intramuscular tetracosactrin should exceed 600 nmol/l. Calculation of the increment is of no value.

Acute Disease↗
PubMed1991

In vivo neutrophil sequestration within lungs of humans is determined by in vitro "filterability".

Neutrophils are normally delayed in transit through the lung microcirculation, relative to the passage of erythrocytes. This sequestration contributes to a pulmonary pool of neutrophils that may relate to the relative inability of neutrophils to deform compared with erythrocytes when in transit in the pulmonary capillaries. A micropore membrane was used to model the human pulmonary microcirculation, in which cell deformability was measured as the pressure developed during filtration of the cells through the membrane at a constant flow. We demonstrated a significant correlation between in vitro deformability and in vivo lung sequestration of indium-111-labeled neutrophils in 10 normal subjects (r = 0.69, P less than 0.02). In eight patients with stable chronic obstructive pulmonary disease, this relationship was not significant (r = -0.2, P greater than 0.05). Furthermore, in a subject with microscopic pulmonary telangiectasia known to allow significant passage of 30-microns microspheres, neutrophils passed through the lungs without delay. Moreover, neutrophils from patients studied acutely with an exacerbation of chronic obstructive pulmonary disease were temporarily less deformable (P less than 0.01). These studies confirm that cell deformability is an important determinant of the normal neutrophil sequestration within the lungs. Changes in cell deformability may alter the extent of this sequestration.

Aged↗
PubMed1991

Neutrophil retention in the lungs of patients with chronic obstructive pulmonary disease.

In order to study neutrophil traffic in the lungs of humans, we harvested autologous neutrophils and radiolabeled them with indium-111 prior to reinjection. The passage of these [111In]neutrophils through the pulmonary vasculature was compared with that of [99mTc]erythrocytes in normal elderly subjects and in patients with chronic obstructive pulmonary disease (COPD). Neutrophil sequestration within the lungs of seven normal subjects, 10 min after reinjection, correlated with local erythrocyte transit times in the lungs (tau = 0.72, p less than 0.001). This relationship was lost in patients with COPD. In seven patients studied during an acute exacerbation of COPD, neutrophil retention was higher during the first passage through the lungs (mean, 22.0 SD 14.1%) compared with 14 patients studied when their condition was stable (16.3 SD 3.4%, p less than 0.001), or to the normal elderly subjects (13.7 SD 7.0%, p less than 0.001). In addition, the subsequent rate of neutrophil washout from the lungs was slower in patients with acute COPD (1.93 SD 0.66 x 10(-3)s1) than in those with stable disease (3.08 SD 1.8 x 10(-3)s-1, p less than 0.02). Neutrophil retention in the lungs correlated inversely with the extent of emphysema, assessed quantitatively by CT scanning (tau = 0.68, p less than 0.05). Thus, patients presenting with acute exacerbations of COPD have an increased neutrophil burden in the pulmonary vasculature with the potential for increased lung proteolysis.

Aged↗
PubMed1991

Lack of effect of N-acetylcysteine on the release of oxygen radicals from neutrophils and alveolar macrophages.

N-acetylcysteine (NAC) is rapidly de-acetylated in vivo to cysteine (CYSH), a precursor of glutathione (GSH) which is an antioxidant in cells and body fluids. We investigated the effect of oral administration of N-acetyl cysteine for 5 days on the spontaneous and stimulated generation of hydrogen peroxide (H2O2) and superoxide anion (O2-) from human and rat phagocytic leucocytes. Alveolar macrophages (AM) were obtained by bronchoalveolar lavage (BAL) in control rats and rats given NAC in their drinking water. Neutrophils (PMNL) were harvested from whole blood in normal nonsmoking volunteers before and after NAC was given by mouth. The stimulated release of H2O2 and O2 from both rat AM and human PMN was not changed by administration of NAC. However, a small but significant increase was observed in both the spontaneous generation of O2- from rat AM and the spontaneous generation of H2O2 from human PMNL. Administration of NAC significantly increased cysteine levels in human plasma and rat BAL, but the levels in human PMNL and rat AM after NAC did not differ from control levels. GSH levels were not altered significantly by NAC.

Acetylcysteine↗
PubMed1990

Assessment of four monoclonal antibodies as serum markers in breast cancer.

Four monoclonal-antibody-defined serum markers (CA15-3, HMFG1, HMFG2 and NCRC-11) were examined in five groups of subjects: controls, benign breast disease and stage I/II, stage III and metastatic breast cancer. None of the markers were significantly elevated in primary breast cancer (i.e. stage I/II or stage III) compared with controls or patients with benign breast disease. These markers therefore have no role in screening or in the diagnosis of primary breast cancer. CA15-3, HMFG2 and NCRC-11 were significantly increased in the patients with metastatic breast cancer (P less than 0.001), indicating a potential use in the diagnosis of symptomatic metastases. In patients with metastases, sequential changes in CA15-3 correlated significantly with clinical response to therapy. Thus CA15-3 is a powerful marker of response and in combination with other markers, may provide an objective measurement of response to therapy in patients with advanced breast cancer.

Adult↗