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Biomedical subjects

B D Harrison

Publications and source records attributed to B D Harrison.

At least 91 records · Page 5Linked to original sources
PubMed1982

Renal function in patients with chronic hypoxaemia and cor pulmonale following reversal of polycythaemia.

The renal function of 7 patients with cor pulmonale and secondary polycythaemia was studied by clearance methods. Their haematocrit (Hct) was initially 62 +/- 6% (mean +/- SD). Their effective renal plasma flow rates (RPF) were reduced and filtration fractions (FF) increased. They were restudied 5-7 days after Hct reduction to 49 +/- 5%. There were no significant changes in glomerular filtration rate (GFR), RPF, FF, effective renal blood flow (RBF) or body weight. However, 5 of 7 patients had a reduction in FF and a fall in body weight. Serial measurements in one patient demonstrated that immediately following the reduction in Hct there was an increase in RPF and a fall in FF, but these reverted to previous levels within 1 week. Overall, a positive correlation was obtained between changes in body weight and FF (r = 0.85, n = 7, p less than 0.015). Polycythaemia is only one factor contributing to a low RPF and high FF in patients with cor pulmonale; reduction of the Hct reduces the FF in some patients and leads to a diuresis which may be beneficial in those with fluid retention.

Body Weight↗
PubMed1979

Changes in arterial blood gases during and after a period of oxygen breathing in patients with chronic hypercapnic respiratory failure and in patients with asthma.

1. Ten patients with chronic hypercapnic respiratory failure (group 1) and eight patients with asthma (group 2) breathed pure O2 from an MC mask for 60 min. Blood gases were measured during this period and for the subsequent 45 min. 2. In mine of ten patients in group 1 and in all eight patients in group 2 arterial O2 tension (Pa,O2) fell to values lower than had been obtained before O2 was given. 3. These undershoots in Pa,O2 are unrelated to changing CO2 stores or to hypoventilation, and are more likely due to persistence of altered ventilation-perfusion ratios associated with O2 breathing. 4. Magnitude of the undershoots is usually small, and periods of less than 15 min of O2 are unlikely to be harmful.

Adolescent↗
PubMed1978

Lung function in acromegaly.

Lung function has been assessed by spirometry, body plethysmography, flow volume loops and single breath transfer factor in thirty patients with acromegaly. Having excluded eight patients with kyphosis and/or clinical or radiological evidence of pulmonary venous hypertension we have found a significant correlation between duration of acromegaly and lung size as assessed by total lung capacity. Excluding the same eight patients we have found evidence of small airways narrowing in eight patients, seven of these eight had had acromegaly for nine years or longer, and the duration of acromegaly was significantly longer in the patients with small airways narrowing than in those without. In the absence of other recognized causes it is possible that small airways narrowing in acromegaly is caused either by the increased whole blood volume with pulmonary vascular engorgement, or by increase in size of the soft tissues of the small conducting airways. Six of the eight patients with kyphosis and/or pulmonary venous hypertension also had evidence of small airways narrowing. Thus fourteen of the thirty patients with acromegaly had small airways narrowing. Five men had evidence of extra thoracic airway narrowing and in four the duration of acromegaly was ten years or longer. We conclude that the increase in total lung capacity, the incidence of small airways narrowing and the incidence of upper airway narrowing are all related to the duration of acromegaly. It seems that once duration exceeds eight years patients are very likely to develop abnormalities of lung function either primarily from the effects of acromegaly on the airways and lung or secondarily from the associated cardiovascular and thoracic skeletal abnormalities. It seems probable that the small airways and upper airway narrowing contribute to the morbidity and mortality of this disease. This study provides further evidence that acromegaly should be treated early.

Acromegaly↗
PubMed1976

Upper airway obstruction--a report on sixteen patients.

In sixteen patients with upper airway obstruction, breathlessness was a symptom in all with maximum mid vital capacity flow rates in inspiration or expiration of 1-7 litres per second or less. With one exception, all these patients had stridor. The stridor was inspiratory in nine, expiratory in one and both inspiratory and expiratory in two. There was no diagnostic difficulty in the twelve patients with extrathoracic airway obstruction and in this group tests of inspiratory flow (forced inspired volume in one second, peak inspiratory flow or maximum mid inspiratory flow) were of most value in following the progression of the disease and the response to treatment. Flow volume loops were particularly useful where extrathoracic obstruction and diffuse intrapulmonary airway obstruction co-existed. The two patients with intrathoracic upper airway obstruction caused considerable difficulty with diagnosis and both were initially thought to have, and treated unsuccessfully for, asthma. In each patient flow volume loops showed a low flow expiratory plateau, diagnostic of severe intrathoracic airway obstruction but recorded in the absence of any clinical or radiographic features of emphysema. An obstructing lesion of the intrathoracic trachea was therefore suspected and this was confirmed by tracheal tomography. In one patient serial expiratory flow volume curves demonstrated the combination of intrathoracic upper and lower airway obstruction. Two patients had tracheal stenosis in the region of the suprasternal notch. Each showed a characteristic twin humped expiratory flow volume curve and in one patient the stenosis was demonstrated both physiologically and radiologically to move in and out of the thorax. The importance of a standard posture during serial measurements is emphasized. The ratio of forced expired volume in one second measured in millilitres, to the peak expiratory flow measured in litres per minute, was of limited value if differentiating upper from lower airway obstruction in these patients. It is concluded that upper airway obstruction is likely to become more common and that respiratory function tests, in particular the flow volume loop, play an essential part in the recognition and management of this problem.

Adolescent↗
PubMed1975

Tuberculin reaction in adult Nigerians with sputum-positive pulmonary tuberculosis.

Forty-six of sixty-eight rural Nigerian adult patients with sputum-positive pulmonary tuberculosis (P.T.B.) had skin reactions of less than 10 mm. in response to 4 or 5 tuberculin units of purified protein derivative (P.P.D.). The size of the reaction correlated significantly with serum albumin and transferrin concentrations. The diminished reaction in these patients seems to be part of a generalized depression of cell-mediated immunity associated with undernutrition rather than a specific depression of P.P.D. reactivity associated with overwhelming antigen load. It is concluded that the tuberculin test is of no value in the diagnosis of P.T.B. in this community, either in individual cases or epidemiological surveys, unless combined with a biochemical assessment of the person's nutritional status.

Adolescent↗
PubMed1975

Silicosis among grindstone cutters in the north of Nigeria.

Many of the grindstones used in Nigerian homes are quarried from sandstone in a small group of villages near Kano in the extreme north of the country. Of an unselected group of 126 stonecutters from two of these villages 49 were found to have radiographic evidence of silicosis, with progressive massive fibrosis in 17. Those with silicosis had worked longer in the quarries than 77 whose radiographs showed no evidence of silicosis. Sixty-three per cent of the silicotics had respiratory symptoms, the commonest being breathlessness on moderate exertion. Cough was the earliest symptom in 42%. Only 35% had abnormal physical signs in the cardiorespiratory system, 18% had clearly reduced ventilatory capacity, and airways obstruction was evident in 16%. The prevalence of silicosis in these open-cast sandstone quarriers is unexpectedly high. This is probably explained by the intensity of exposure and the particular kind of sandstone being worked. Reduction of dust exposure in these quarries raises severe practical problems, but the inhabitants of this drought-ridden area can scarcely be expected to abandon their traditional livelihood.

Adolescent↗
PubMed1975

Bronchial asthma in the Nigerian savanna region. A clinical and laboratory study of 106 patients with a review of the literature on asthma in the tropics.

One hundred and six asthma patients were studied in Zaria in the Nigerian savanna region. This group resembled hospital attenders in general in containing a disproportionately large number of immigrants from southern Nigeria and students undergoing higher education. Childhood asthma was rare. Asthma started after the age of 19 years in 69 per cent of patients. Twenty-seven per cent gave a history of rhinitis but none had had eczema. Twenty-two per cent gave a family history of asthma. Cutaneous hypersensitivity to house dust supported by a history of attacks being precipitated by dust was found in 41 per cent of patients. Asthma was worst in the rainy season in 45 per cent of patients. Mites were found in mattress dust samples; the mean count was 243 mites per g dust; Dermatophagoides farinae formed 86-6 per cent of the total mite population. The variability of airways obstruction averaged 50 per cent of maximum values for forced expiratory volume in the first second (FEV1) and peak expiratory flow (PEF). The median severity of airways obstruction measured as FEV1/VC per cent was four standard deviations below predicted normal. Eighty-seven per cent of patients were positive to prick skin tests with one or more allergens. The commonest reactions were to house dust (58 per cent), house dust mite (45 per cent) and Dermatophagoides farinae (44 per cent). Fifty-one per cent of a group of controls were also positive on skin testing but the pattern of responses was different from the asthmatic patients. This high proportion of reactors is explained by high allergen load. Serum IgE levels were lower in the asthmatics than in a group of healthy controls who showed the very high levels characteristic of some African populations. We suggest that the controls were protected from atopic disease by developing high blocking levels of non-specific IgE, perhaps in response to gut helminths. The clinical pattern of asthma in Zaria is compared with other countries in the tropical and temperate zones. The particular problems of treating asthma in developing tropical countries are discussed.

Adolescent↗