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Biomedical subjects

N M Johnson

Publications and source records attributed to N M Johnson.

At least 55 records · Page 3Linked to original sources
PubMed1985

A comparison of three high doses of ipratropium bromide in chronic asthma.

We have performed a double-blind crossover study in nine patients with stable chronic asthma, in order to evaluate the effects of three doses of the anticholinergic bronchodilator ipratropium bromide (80 micrograms, 200 micrograms and 400 micrograms) given by metered dose inhaler. These doses are larger than the recommended dose (40 micrograms). All three doses of the drug produced significant bronchodilation from 15 minutes to 5 hours. Some small but statistically significant differences were found in favour of the 200 micrograms and 400 micrograms doses when compared with the 80 micrograms dose and the duration of action of the 400 micrograms dose was longer than that of 200 micrograms dose. The clinical usefulness of these small differences remains to be assessed.

Adult↗
PubMed1985

Radiographic features in patients with pulmonary manifestations of the acquired immune deficiency syndrome.

The radiographic findings in 14 episodes of pulmonary pathology, occurring in 13 patients with the acquired immune deficiency syndrome (AIDS) are described. The patients presented over a 15-month period. All were homosexual men with serum antibodies to human T-cell lymphotrophic virus III. Pneumocystis carinii pneumonia was the most common manifestation, occurring in seven of the 14 episodes. Radiographic appearances in five of these were classical, with bilateral perihilar ground-glass shadowing initially. In one the appearances were complicated by a superadded bacterial infection and in one the chest radiograph was normal. Bacterial infections occurred in five of the 14 episodes and, when present, showed the characteristic radiographic appearances of the causative organism. Three patients had widespread Kaposi's sarcoma. Bronchoscopy, broncho-alveolar lavage and transbronchial biopsy were often necessary to identify the causative agent. They were also indicated when atypical radiographic appearances occurred during the course of treatment as additional organisms could be found. The radiographic appearances of the conditions reported are felt to be sufficiently characteristic for the radiologist to play a useful role in suggesting the diagnosis and in monitoring the progression of disease in these patients.

Acquired Immunodeficiency Syndrome↗
PubMed1985

Human mast cells recovered by bronchoalveolar lavage: their morphology, histamine release and the effects of sodium cromoglycate.

Mast cells make up between 0.5 and 3% (mean 1.35%) of total cells recovered by bronchoalveolar lavage (BAL). The majority of these cells have the morphological characteristics of mucosal mast cells in that they fail to stain in the alcian blue-safranin reaction after fixation in formol-saline but stain well after fixation in Carnoy's solution. Cells staining with berberine sulphate were seen in only four of the 26 lavages. BAL cells released histamine in response to anti-human immunoglobulin E (IgE) in a dose-dependent manner that was optimal at a dilution of anti-IgE of 1:100. Maximum release was obtained by 2 min. Histamine release was completely inhibited by a combination of 2-deoxyglucose (5 mmol/l) and antimycin A (1 mumol/l). Disodium cromoglycate (DSCG) significantly inhibited this histamine release at 1 mmol/l (P less than 0.02), 100 mumol/l (P less than 0.002) and 10 mumol/l (P less than 0.003), with maximum inhibition of 50.1% at 10 mumol/l.

Adult↗
PubMed1985

Early experience and difficulties with bronchoalveolar lavage and transbronchial biopsy in the diagnosis of AIDS associated pneumonia in Britain.

Bronchoalveolar lavage and transbronchial biopsy have been used as adjuncts to the management of patients with pneumonia associated with the acquired immunodeficiency syndrome (AIDS) at the Middlesex Hospital and the experience gained and difficulties encountered in the first five cases are reported. Widely varying organisms were isolated from lavage aspirates, some of which may have been nasopharyngeal contaminants, and organisms cultured from the transbronchial biopsy specimens may offer a better guide to antimicrobial treatment. Pneumocystis carinii was found in two of the patients. In view of the potentially serious toxicity of high dose co-trimoxazole, continuation of this treatment may be inadvisable if Pneumocystis carinii is not identified by all available methods unless there are strong clinical grounds to suspect its presence.

Acquired Immunodeficiency Syndrome↗
PubMed1985

Comparison of intravenous digital subtraction angiography with radionuclide ventilation-perfusion lung scanning in patients with suspected pulmonary embolism.

Fifty one patients with suspected pulmonary embolus were studied by radionuclide ventilation-perfusion scanning and intravenous digital subtraction pulmonary angiography. In 31 patients the results of both investigations were reported as negative and in a further 11 both results were reported as positive, giving a concordance rate of 82.3%. In nine patients there was disagreement between the two investigations and an attempt to resolve this difference on the basis of clinical data was made. On this basis digital subtraction angiography would have falsely classified three patients as not having an embolus who were correctly identified by radioisotope scanning. Angiography would, however, have correctly classified four patients misclassified by ventilation-perfusion scanning. The relative merits of digital subtraction angiography and radionuclide lung scanning are discussed.

Adult↗
PubMed1985

Sarcoidosis is not associated with the HTLV III virus.

Superficial immunological similarities between sarcoidosis and AIDS led to this radioimmunoassay survey of serum antibodies to HTLV III virus in 17 patients with active sarcoidosis, 8 with peripheral lymphadenopathy. Serum antibodies were negative in all patients with sarcoidosis.

Antibodies, Viral↗
PubMed1984

Differences in the effect of mediastinal radiotherapy on lung function and the ventilatory response to exercise.

To examine the effect of lung inflammation on lung volumes and carbon monoxide transfer and their relationship to the ventilatory and gas exchange responses to exercise, a prospective study was performed in patients having Hodgkin's disease, with no evidence of intrathoracic involvement, who received prophylactic mantle-field radiotherapy to the chest. From 6 weeks to 6 months from the start of therapy, vital capacity (FVC) was on average 10.4% lower than during the baseline period and the total transfer of carbon monoxide (TLCO) was 10.5% lower. Minute ventilation (VE) at any given work load during an incremental exercise test was on average 10.5% higher than baseline. The stimulation of ventilation after radiotherapy was present at all work rates, but greater at high work rates. A number of other changes in the ventilatory and gas exchange responses to exercise were also seen. Most of these lay outside the range of variability observed in a group of normal subjects tested concurrently with the patients. There was a poor, but statistically significant, positive correlation between reduction in FVC and increase in VE after radiotherapy and between reduction in carbon monoxide transfer and increase in VE. A significant correlation between reduction in FVC and change in respiratory rate was also seen after radiotherapy, together with a significant inverse correlation between increase in respiratory rate and fall in tidal volume. The ratio of VE to oxygen consumption, the ventilatory equivalent for oxygen, was calculated at each work rate. There was a negative correlation between the mean increase in this parameter, averaged over all work rates, and the reduction in FVC and TLCO, i.e. the greatest stimulation of breathing relative to metabolic demand occurred in those patients with the least change in lung volume.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

Anergy in sarcoidosis: the role of interleukin-1 and prostaglandins in the depressed in vitro lymphocyte response.

We have shown that peripheral blood monocytes from patients with sarcoidosis release reduced amounts of interleukin-1 (IL-1) when compared with normals. In part, this defect explains the relative in vitro unresponsiveness of T lymphocytes from patients with sarcoidosis as measured by mitogen- or antigen-induced lymphocyte transformation. The addition of supernatants containing pre-formed IL-1 partially restored this defect. This enhancement was found to be additive to the previously described effect of indomethacin, an inhibitor of prostaglandin synthesis. Thus, it would appear that the activated peripheral blood monocytes found in sarcoidosis not only cause reduced lymphocyte proliferation by acting as suppressor cells but are also unable to act as accessory cells in producing IL-1.

Adult↗
PubMed1983

Intrinsic and extrinsic asthma, a shared lymphocyte abnormality.

We have examined in vitro cell-mediated lymphocyte responses to Concanavalin A, (Con. A), and the effects of histamine and indomethacin upon these responses, in normal subjects, and patients with extrinsic and intrinsic asthma, and chronic bronchitis. Lymphocytes from both intrinsic and extrinsic asthmatics are particularly sensitive to histamine-induced suppression of their response to Con. A, and this increased sensitivity was reversed by indomethacin. In these respects, lymphocytes from intrinsic and extrinsic asthmatics behave in an identical fashion, but differ significantly from lymphocytes from both normal subjects and patients with fixed airways obstruction (chronic bronchitis). It is suggested that there is a common immunological mechanism in extrinsic asthma and intrinsic asthma.

Adult↗
PubMed1983

Fenoterol versus salbutamol nebulization in asthma.

A double-blind crossover study was conducted in 10 stable asthmatics comparing 5 mg fenoterol with 5 mg salbutamol, both given via a Hudson nebulizer. Although both drugs caused significant bronchodilatation at the doses used, fenoterol had a significantly greater peak effect than salbutamol and its duration of action was 4 hr as opposed to 3 hr.

Adult↗
PubMed1983

A comparison between a combination of ipratropium bromide plus fenoterol in a single metered dose inhaler (Duovent) and salbutamol in asthma.

The efficacy of a single metered dose inhaler containing a combination of fenoterol (100 micrograms/puff) and ipratropium bromide (40 micrograms/puff) has been assessed in 12 asthmatics. We conclude that the bronchodilator effect of 2 puffs of the combination inhaler was significantly greater than that achieved by 2 puffs of salbutamol (100 micrograms/puff).

Adult↗