Search PubMed⌕ Search

Biomedical subjects

R M Rudd

Publications and source records attributed to R M Rudd.

At least 73 records · Page 4Linked to original sources
PubMed1990

Covered expandable metal stent for recurrent tracheal obstruction.

Rapidly recurrent symptoms of airways obstruction by tumour may require repeated radiotherapy or endoscopic laser treatment--but these procedures may themselves be distressing. Use of a novel coated metal stent may reduce the frequency with which such palliative intervention is required.

Airway Obstruction↗
PubMed1990

Changes in pulmonary microvascular permeability accompanying re-expansion oedema: evidence from dual isotope scintigraphy.

The pathophysiological mechanism of pulmonary oedema following rapid re-expansion of a collapsed lung is poorly understood. It has been suggested that the period of collapse or subsequent reinflation produces an increase in pulmonary microvascular permeability. To investigate this, the pulmonary accumulation of the plasma protein transferrin was measured by radiolabelling it in vivo with indium-113m. Plasma protein accumulation was calculated after correcting the accumulation of transferrin for changes in intrathoracic blood distribution by simultaneously monitoring technetium-99m labelled red blood cells. Functional images of plasma protein accumulation were constructed for the lung fields on a pixel by pixel basis. Investigations were performed on 14 subjects after drainage of a pleural effusion (n = 9) or evacuation of a pneumothorax (n = 5), and on 11 control subjects. Plasma protein accumulation was greater over the regions of lung re-expansion (-0.1-9.6, mean 2.9 x 10(-3)/min) than over the corresponding region of the contralateral lung (-1.2-0.8, mean 0.01 x 10(-3)/min; p less than 0.001). Patients who had undergone re-expansion procedures also had significantly greater plasma protein accumulation than normal controls. Nine of the 14 patients in the re-expansion group had clearly identifiable areas of increased plasma protein accumulation that corresponded to the part of the lung that had been re-expanded; no regional abnormalities were recorded in the control group. These results suggest that the reinflated lung displays abnormal microvascular permeability.

Adult↗
PubMed1990

Bronchography in the assessment of patients with lung collapse for endoscopic laser therapy.

In an attempt to improve selection of patients and the efficacy of endoscopic laser treatment, a bronchographic technique has been developed for patients with tumours causing complete endobronchial obstruction. This technique has shown patent distal airways in 16 out of 17 patients with a collapsed lung or lobe. These airways were abnormally dilated in each case, suggesting bronchiectasis. In one patient the appearances of bronchiectasis were sufficiently severe to decide against attempting treatment. Treatment was not attempted in another patient as a large cavity was seen within the collapsed lung and this was thought to carry a risk of postoperative infection and haemorrhage. Treatment with a neodymium YAG laser under general anaesthesia successfully recanalised the airway in 12 of the 15 remaining patients and was associated with a substantial reduction in breathlessness. The procedure was abandoned prematurely in one patient because of life threatening haemorrhage. In the remaining two patients in whom treatment was unsuccessful bronchography had suggested very extensive endobronchial obstruction. Spirometry and radionuclide lung scans were performed before and after treatment in eight patients treated successfully and showed significant improvements. Four patients were investigated within two weeks of lung re-expansion by repeat bronchography (three patients) or computed tomography (one patient); in each case the calibre of the airways had returned almost to normal. Thus the radiological demonstration of bronchial dilation in a collapsed lung does not necessarily imply a diagnosis of irreversible bronchiectasis and should not be regarded as a contraindication to treatment. It is concluded that preoperative bronchography provides reliable data on the extent of tumour, the patency of the distal airways, and presence of extensive cavitation. This information should facilitate successful laser treatment.

Adult↗
PubMed1989

Six months' chemotherapy for lymph node tuberculosis.

A retrospective report of the experience using the policy of six-month short-course chemotherapy as standard treatment for lymph node tuberculosis is presented. Forty-one patients completed 6 months' treatment as planned. All made a complete recovery, except one who had a 1 cm residual node at the completion of treatment, and one who relapsed four months after treatment, was re-treated and recovered. Nine other patients had changes in treatment because of side-effects (5), drug-resistant organisms (3) and pregnancy (1). Treatment was prolonged in another seven patients, four in error and three because of previous drug treatment. The results suggest that 6 months' treatment of lymph node tuberculosis may be as satisfactory as 9 months', and support the need for a control comparison of these regimens.

Adolescent↗
PubMed1989

Atrial natriuretic peptide concentrations in hypoxic secondary pulmonary hypertension: relation to haemodynamic and blood gas variables and response to supplemental oxygen.

Plasma atrial natriuretic peptide concentrations, measured in samples drawn from the pulmonary artery, were raised in nine of 17 patients with hypoxic pulmonary hypertension but normal right atrial pressures at rest. No relationship was seen between atrial natriuretic peptide concentrations and mean pulmonary artery or right atrial pressure, or calculated pulmonary or systemic vascular resistance. Patients with the most severe hypoxaemia tended to have higher plasma atrial natriuretic peptide concentrations; three patients with no past history of oedema had concentrations more than twice the upper limit of normal. Treatment with supplementary oxygen for 30 minutes reduced pulmonary vascular resistance in all patients but had no significant effect on plasma atrial natriuretic peptide concentration. These findings suggest that atrial natriuretic peptide may be a factor in the control of sodium and water balance in hypoxic cor pulmonale, where the determinants of individual susceptibility to peripheral oedema are not well understood.

Aged↗
PubMed1988

De novo cardiac beta adrenoceptor synthesis in adult rats under normoxic and hypoxic conditions.

Bromoacetylalprenololmenthane (BAAM), an alkylating irreversible beta adrenoceptor antagonist, was used to study in vivo beta adrenoceptor synthesis in adult rat left ventricle under normoxic and hypoxic conditions. In normoxic conditions cardiac beta adrenoceptor density decreased by 50% 15 h after treatment and recovered to control values after about 250 h. A similar decrease in receptor density and pattern of recovery was found in environmental hypoxia. Neither hypoxia nor treatment with BAAM had a significant effect on the dissociation constant of the radioligand. These results show that cardiac beta adrenoceptor synthesis occurs rather slowly and suggest that alteration of the rate of receptor synthesis in hypoxic states is not a major determinant of reported changes in density.

Adrenergic beta-Antagonists↗
PubMed1986

Tissue specific modulation of beta-adrenoceptor number in rats with chronic hypoxia with an attenuated response to down-regulation by salbutamol.

The number of beta-adrenoceptors and their affinity for the radioligand 125I-labelled cyanopindolol (125I-CYP) were measured in crude membrane preparations of left ventricle, spleen and lung from Wistar rats exposed to 28 days continuous hypoxia. beta-Adrenoceptor density in the left ventricle was not significantly altered after exposure to chronic hypoxia (binding site maxima, Bmax.: normoxic control 36 SEM 5, hypoxic 24.8 SEM 2 fmol/mg of protein). There was no change in beta-adrenoceptor number in the spleen in response to chronic hypoxia (Bmax.: normoxic control 76 SEM 19 fmol/mg of protein, hypoxic 80 SEM 15 fmol/mg of protein). Chronic hypoxia resulted in a significant increase in beta-adrenoceptor number in lung tissue (binding site maxima, Bmax.: normoxic control 406 (SEM 31) fmol/mg of protein; hypoxic 535 (SEM 30) fmol/mg of protein, P less than 0.01 without change in the dissociation constant (KD) of the radioligand. beta-Adrenoceptor subtypes in lung homogenates were studied by establishing displacement curves for 125I-CYP by ICI 118551 (a selective beta 2-antagonist). A significant difference was seen in the proportion of beta 1-/beta 2-adrenoceptor subtypes after hypoxia (normoxic control 66 SEM 2.5%, hypoxic 79 SEM 2.4% beta 2-adrenoceptors, P less than 0.01). alpha 1-Adrenoceptor number in lung membranes was measured with 125I-labelled 2-[beta-(4-hydroxyphenyl)ethylaminomethyl]tetralone (125I-HEAT). No difference was seen in the number of alpha 1-receptors in normoxia and in chronic hypoxia [Bmax.: normoxic control 48 (SEM 3), hypoxic 48 (SEM 5) fmol/mg of protein].(ABSTRACT TRUNCATED AT 250 WORDS)

Albuterol↗
PubMed1986

Technetium-99m-glucoheptonate lung imaging; has it a role in the diagnosis of bronchial carcinoma?

It has been shown by Vorne et al. and Passamonte et al. that technetium-99m-glucoheptonate (Tc-GH) concentrates in bronchial carcinomas. The two studies reported similar sensitivities (88 and 91%, respectively) but discordant specificities (88 and 10%, respectively). In order to assess the uptake of Tc-GH in bronchial carcinomas we performed lung imaging on patients with an abnormal chest radiograph who were undergoing routine investigations for bronchial carcinoma. 108 patients (85 carcinoma, 23 non-carcinoma) were given 555 MBq (15 mCi) Tc-GH intravenously and scanned 5 h later. Images were assessed by one investigator (J.A.L.) without knowledge of the patient's clinical details or other results. Localized uptake of Tc-GH was seen in 71 out of 85 patients who proved to have bronchial carcinoma. Uptake was also seen in 16 out of 23 patients with a variety of non-malignant lung conditions. Sensitivity for bronchial carcinoma was 84%, and specificity 30%. Uptake did not vary significantly with histology. Eleven out of 12 patients with proven tuberculosis had increased uptake of Tc-GH; two of those patients also had inactive lesions which did not concentrate the tracer. In conclusion, Tc-GH is of limited value in the diagnosis of bronchial carcinoma, because of its low specificity. A possible role in the diagnosis of active tuberculosis may exist, following further assessment.

Adult↗
PubMed1986

Asbestos fibres in bronchoalveolar lavage fluid from asbestos workers: examination by electron microscopy.

The uncoated and coated fibre load in bronchoalveolar lavage (BAL) fluid was assessed using light microscopy, scanning electron microscopy, and x ray microanalysis in 15 subjects with previous, unprotected exposure to asbestos, including three with clinical and radiological evidence of asbestosis, and in 13 urban dwelling control subjects with no known occupational exposure to asbestos. The mean ferruginous body count per ml BAL fluid in asbestos exposed subjects as determined by light microscopy was 52 (range 0-333). No ferruginous bodies were detected in control subjects. The mean fibre count per ml BAL fluid in asbestos exposed subjects as determined by electron microscopy was 793 (133-3700), significantly greater than 239 (44-544) in controls (p less than 0.05). Electron microscopic counts correlated with duration of previous exposure to asbestos (r = 0.47, p less than 0.05) and with percentage neutrophil counts (r = 0.53, p less than 0.025). There was no relation between electron microscopic fibre counts and light microscopic ferruginous body counts. In 11 asbestos exposed cases x ray microanalysis confirmed the presence of asbestos and in six the asbestos fibre type was clearly identified. Of five subjects showing no asbestos bodies by light microscopy, all showed fibres by electron microscopy, and in three cases the presence of asbestos was confirmed by microanalysis. Among control subjects, fibres were either large organic fibres or smaller particles which microanalysis showed were not asbestos. In only one control case were a few fibres identified which were confirmed as asbestos fibres on microanalysis. Electron microscopic examination of BAL fluid may confirm past exposure to asbestos and probably gives a crude quantitative estimate of asbestos load.

Adult↗
PubMed1986

The effect of systemic beta-2 adrenergic agonist therapy on the pulmonary hypertensive response to chronic hypoxia in rats.

Chronic hypoxia produces polycythemia, pulmonary hypertension, muscularization of peripheral pulmonary arteries, and right ventricular hypertrophy. The present study was designed to investigate the effects of systemic administration of a beta-2 adrenergic agonist on these responses. Male Wistar rats (9 or more in every group) were maintained in room air or 10% oxygen for 28 days. In the first experiment, they were treated with albuterol at various doses (0.05 mg/kg, 0.1 mg/kg, 0.5 mg/kg) twice during exposure to intermittent hypoxia (10 h/day). In the second experiment, rats were treated with albuterol 2.5 mg/kg subcutaneously twice daily during continuous hypoxia. Control animals in normoxia and hypoxia received 0.1 ml saline at equivalent times. All hypoxic groups developed polycythemia, significantly increased right ventricular systolic pressure, and right ventricular hypertrophy. At doses of albuterol that did not produce cardiac hypertrophy in normoxia, treatment had no effect on the development of right ventricular hypertrophy. With lower doses of albuterol in hypoxia, there was a trend towards an increase in hematocrit, but overall this did not reach significance. Treatment with high dose albuterol in continuous hypoxia significantly increased the hematocrit and enhanced the remodeling of the pulmonary vasculature (Hematocrit: saline-treated, 57.7 SEM 1.9; albuterol-treated, 63.4 SEM 1.7; p less than 0.05. Percentage of thick-walled peripheral vessels: saline-treated, 19.4 SEM 0.60; albuterol-treated, 22.7 SEM 0.85; p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic beta-Agonists↗
PubMed1986

Pulmonary epithelial permeability: vascular background effects on whole lung and regional half-time values.

Pulmonary epithelial permeability was first measured by Jones et al. We have adapted their technique for use with a gamma camera. Both regional half-time values and background correction factors vary from apex to base in the lung. Examination of two methods of background correction show: that inter-segmental half-time comparison is possible without applying individual correction factors to regions. the use of a region of interest with similar vascular supply to that of the lung eliminates the need for a background correction technique that relies upon an intravenous injection of radioisotope. The inter-renal area provides such a vascular area.

Adult↗
PubMed1985

Clearance of 99m-technetium-labelled DTPA in asbestos-exposed subjects without clinical or radiological evidence of interstitial lung disease.

The half-time clearance of an inhaled aerosol of 99m-technetium-labelled diethylene triamine pentacetate from lung to blood (T1/2LB) was measured using a gamma camera in 20 non-smoking subjects (mean age 54, range 40-69 years) with previous occupational asbestos exposure, but no clinical or radiological evidence of asbestosis, and 20 non-smoking normal subjects (mean age 54, range 40-62). Mean T1/2LB was 44.7 minutes (range 12-102) in exposed subjects, significantly less than 57.2 minutes (range 30.5-109) in normal subjects (P less than 0.05). There was no correlation between age and T1/2LB in either group. In exposed subjects T1/2LB showed a weak rank correlation with the membrane component of DLco (Dm) (r = 0.40, P less than 0.05) but no significant correlation with FVC, TLC, DLco, Kco, resting Pao2 or change in Pao2 on exercise. In six exposed subjects T1/2LB was shorter than in any of the normal subjects. These six did not differ from the other 14 exposed subjects in any physiological variables. T1/2LB is abnormal in some asbestos-exposed subjects without clinical, radiological or physiological evidence of asbestosis. Follow-up will show whether it is an early indicator of development of interstitial lung disease.

Adult↗