Biomedical subjects
C Borland
Publications and source records attributed to C Borland.
Nitric oxide yields of contemporary UK, US and French cigarettes.
To determine what governs nitric oxide (NO) yields of cigarettes and to obtain a range of yields for contemporary cigarettes 17 UK, 14 US, 8 French and 1 Turkish brand were analysed using a chemiluminescent analyser and standard smoking machine. The country of origin appeared to be the major factor affecting NO yield. US and French brands exceeded UK values by 3-5 fold. Apart from a reduced NO yield in UK ventilated filtered brands, the design of a cigarette and its tar, nicotine and carbon monoxide (CO) yield had little effect on NO yield. It is argued that these international differences in NO yields reflect differences in the nitrate content of tobaccos traditionally used in manufacture in those countries over many years. Despite their probable increased lifetime exposure to NO (and by implication nitrosamine exposure) there appears to be little evidence that US and French smokers are at greater risk of lung disease than their UK counterparts.
Chemical specificity of coughing in man.
The purpose of this study was to test whether cough response to inhaled ultrasonically nebulized fluid is dependent on the ionic content of the fluid. Coughing was recorded in human volunteers during inhalation of aqueous solutions in a series of double blind randomized experiments. The occurrence of cough was found to be dependent on the concentration of chloride ions in the inhaled fluid, cough frequency progressively increasing as chloride ion concentration was reduced. It is proposed that the ion composition of the surface lining fluid of the airway may moderate the cough response by means of a chemo-receptor, although tonicity may also be important.
Biochemical and clinical correlates of diuretic therapy in the elderly.
To estimate the frequency of diuretic-related electrolyte disorders in the elderly, 561 consecutive admissions to three acute geriatric units were studied. For the 287 admissions to one unit, discharge/death diagnoses were also examined in relation to admission diuretic therapy. Sodium concentrations were significantly lower, and urea and creatinine significantly higher, in patients on diuretics, though the size of the differences was small. Comparing different preparations sodium concentrations were significantly lower on Moduretic than on Dyazide or Navidrex K and on frusemide when combined with a potassium-retaining diuretic rather than a potassium supplement. Potassium concentrations were significantly lower on Bendrofluazide alone compared to Navidrex K or Moduretic. Diuretics were positively associated with cardiac failure, ischaemic heart disease, airflow obstruction and obstructive large bowel disorders but negatively with Parkinson's disease. No significant association was found with falls, immobility or confusion. Major electrolyte disorders on diuretics appear to be unusual but important differences exist between preparations. Similarly major illness resulting from diuretic therapy is rare but minor morbidity may be more common.
Pulmonary epithelial permeability after inhaling saline, distilled water "fog" and cold air.
It is recognized that hyperventilation of cold air and the inhalation of fine mists of distilled water provoke significant bronchoconstriction in the asthmatic individual, yet little is known as to how these provocations affect the structural integrity of the alveolar epithelial membrane. In 11 normal subjects, the following effects have been studied: cold air hyperventilation for three minutes, inhalation of 80 L of ultrasonically nebulized distilled water "fog," and 80 L of isotonic saline "fog" on the half time clearance (T1/2) from the alveoli of technetium 99m diethylene triamine penta acetate (DTPA), inhaled as an aerosol. The DTPA T1/2 provided a measurement of pulmonary epithelial permeability.
Do the oxides of nitrogen in cigarette smoke cause emphysema in smokers?
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Hyponatraemia and Moduretic (amiloride plus hydrochlorothiazide)
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Carbon monoxide yield of cigarettes and its relation to cardiorespiratory disease.
Estimates of the carbon monoxide yield of their cigarettes have been obtained for 4910 smokers (68% of all smokers) in the Whitehall study of men aged 40 to 64. In the 10 years after examination 635 men died. When men smoking cigarettes with high carbon monoxide yield were compared with those smoking cigarettes with a low yield, and after adjusting for age, employment grade, amount smoked, and tar yield, the risk of death was 32% lower for coronary heart disease, 49% higher for lung cancer, and 10% lower for total mortality; these differences were not statistically significant. Among men who said that they inhaled the risk of fatal coronary heart disease was 51% lower in the high carbon monoxide group (p less than 0.01), while the risk of lung cancer was 75% higher. These results provide no evidence that a smoker can reduce his risk of death by smoking a brand with a low carbon monoxide yield; he might even increase it. The complex interactions between characteristics of the smoker, smoking behaviour, constituents of tobacco smoke, and health are again demonstrated.
Methemoglobin levels in smokers and non-smokers.
The authors analyzed the blood of a group of 336 smokers and 336 non-smokers to determine if tobacco smoke, potentially the major source of nitrogen oxide pollution for 40% of the adult population, significantly reduces oxygen carrying capacity as a result of methemoglobin formation. Each blood sample was analyzed for carboxyhemoglobin, methemoglobin, and hemoglobin using an automated spectrophotometer. The mean value of methemoglobin in the smokers did not exceed that in the non-smokers; in fact, the level in the non-smokers was significantly greater. As expected, carboxyhemoglobin levels in smokers substantially exceeded those in non-smokers. The authors conclude that methemoglobin arising from cigarette smoke exposure does not interfere with the oxygen carrying capacity of the blood in smokers.