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Biomedical subjects

K R Patel

Publications and source records attributed to K R Patel.

At least 109 records · Page 6Linked to original sources

A pulmonary survey of grain handlers in the West of Scotland.

A pulmonary survey was undertaken in a large granary in the West of Scotland. The lung functions and respiratory symptoms were compared in nineteen atopic and fifty-six non-atopic grain handlers with reference to their smoking habits and also to forty-eight control subjects with no previous exposure to grain dust. Cigarette smokers from the granary workers and the control group had more respiratory symptoms and significantly lower PF, FEV1, V25 and V50. The atopic grain handlers, on the other hand, had better ventilatory functions compared to non-atopic workers. This difference in the atopic group may be related to their lower cigarette consumption, shorter service in the granary or the process of self selection. The grain handlers with wheeze or breathlessness at work had significantly higher incidence of restrictive type MEFV curves and this could not be attributed to increased cigarette consumption, atopy or longer duration of employment and there was no correlation between severity of symptoms and occupational exposure. Although PF, FEV1, FVC, V25, V50 and V75 failed to show significant differences in granary workers and controls, the shape of MEFV curve may have significance as a sensitive indicator of the effect of grain dust as a preclinical stage.

Edible Grain↗

The effect of calcium antagonist, nifedipine in exercise-induced asthma.

The effect of nifedipine was studied in fifteen patients with exercise-induced asthma. Nifedipine inhibited the exercise-induced fall in FEV1 almost completely in four patients, offered partial protection in a further nine patients and had no effect in the remaining two patients. It is suggested that mediator release which is dependent on free calcium ions may play an important role in exercise-induced asthma and calcium antagonists may inhibit post-exercise bronchoconstriction by their blocking effect on calcium channels of the mast cells.

Adolescent↗

The effect of verapamil on histamine and methacholine-induced bronchoconstriction.

Calcium antagonist, verapamil given by inhalation did not alter histamine bronchial hyper-reactivity in ten patients with extrinsic bronchial asthma and similarly did not modify methacholine-induced bronchoconstriction in further five patients. In eight non-asthmatic subjects verapamil reduced histamine sensitivity with increase in PC20H from 8.07(+/- 2.33) to 12.10(+/- 2.71, P less than 0.05) but failed to have an effect on methacholine sensitivity in five controls. The failure of inhaled verapamil to modify histamine and methacholine bronchial hyper-reactivity in asthmatic patients and the beneficial effect of calcium antagonists in exercise asthma suggests that these agents may act predominantly on the mast cell degranulation rather than the bronchial smooth muscle.

Adolescent↗

An aldehydophosphoglycolipid from Acholeplasma granularum.

A novel phosphoglycolipid and a triglucosyl diacylglycerol were found among the lipids of Acholeplasma granularum. The tentative structure of the phosphoglycolipid was determined to be a phosphotriester, [beta-D-glucopyranosyl-(1 leads to 1)-X-glycerol-3-O-] [D-glyceraldehyde-3-O-] [1,2-diacyl-X-glycerol-3-O-kojibiosyl-6-O-]phosphate. The structure assigned to the triglucosyl lipid was beta-D-glucopyranosyl-(1 leads to 3)-alpha-D-glucopyranosyl-(1 leads to 2)-alpha-D-glucopyranosyl-(1 leads to 1)-diacylglycerol.

Acholeplasma↗

Role of ascorbic acid in auxin induced cell elongation--a cytochemical study.

Cytochemical detection of ascorbic acid in cultured root tips of Zea mays shows that dividing cells accumulate ascorbic acid in the cytoplasm. The localization pattern alters in the root tip as the cells begin to elongate. In elongating cells ascorbic acid is distinctly localized on cell walls. Ascorbic acid content per cell increases with the onset of cell elongation. Fully elongated cells contain fivefold more ascorbic acid than meristematic cells. Cytophotometric analysis reveals a sharp and positive correlation (r = +0.93) between percentage increase in content of ascorbic acid per cell and corresponding increase in cell size at different phases of cell elongation. IAA treatment to the roots raises the content of ascorbic acid per cell with a parallel increase in size of cell. Involvement of ascorbic acid in IAA induced cell elongation is discussed.

Ascorbic Acid↗

Effect of dopamine on airways conductance in normals and extrinsic asthmatics.

1 Specific conductance was measured before and after infused and/or inhaled dopamine in nine normal subjects and twelve patients with extrinsic bronchial asthma. 2 There was no significant change in conductance in either group. 3 The alpha-adrenergic receptor antagonist thymoxamine infused in combination with dopamine had no significant effect on conductance in three asthmatics. 4 It is concluded that dopamine has no acute effect on airways resistance and that specific dopamine receptors are unlikely to exist in human airways.

Adolescent↗

Effect of external environmental factors on the morphology of Spiroplasma citri.

Spiroplasma citri was examined by electron microscopy for morphological changes when maintained under a variety of conditions. PPLO serum fraction maintained spiral and helical morphology of S. citri at pH values of 8.0, 7.5, and 7.0, but only partially at pH 6.0 and 5.0. The absence of PPLO serum fraction resulted in round, deteriorated cells at all pH values tested. Bovine serum albumin (BSA), Phytone, soluble starch, potato starch, spermine, lipid-extracted PPLO serum fraction, and lipid-extracted BSA could substitute for PPLO serum fraction in maintaining spiral and helical morphology at pH 7.5. At pH 5.0, only BSA, lipid-extracted BSA, and lipid-extracted PPLO serum fraction were effective. Only BSA supported growth of S. citri for more than two transfers, whereas all other substitutes could not support growth longer than two transfers.

Blood↗

Sodium cromoglycate and ipratropium bromide in exercise-induced asthma.

In thirteen patients with extrinsic asthma the effects of placebo, sodium cromoglycate, ipratropium bromide, and ipratropium bromide plus sodium cromoglycate were studied in a random double-blind fashion to assess their inhibitory action in exercise-induced asthma (EIA). Exercise testing consisted of steady state running on an inclined treadmill for up to eight minutes. In eight of the 13 patients studied the baseline ratio of expiratory flow at 50% vital capacity (VC) breathing helium-oxygen (V50He) to V50air was over 1.20 and they were called responders; the remaining five patients were called non-responders. There was a significantly lower baseline maximum mid-expiratory flow rate (MMEF) in non-responders (P less than 0.02) as compared to responders but no difference in forced expiratory volume in one second (FEV1) or forced vital capacity (FVC). Sodium cromoglycate (P less than 0.02), ipratropium bromide (P less than 0.01), and ipratropium bromide plus spdium cromoglycate (P less than 0.01) all significantly inhibited the percentage fall in FEV1 after exercise in the responders. Ipratropium bromide had no preventive action on non-responders, unlike sodium cromoglycate (P less than 0.05) and ipratropium bromide plus sodium cromoglycate (P less than 0.02). It is postulated that mediator release is an important factor in development of EIA in most extrinsic asthmatics, whereas cholinergic mechanisms are relevant only in those patients in whom the main site of airflow obstruction is in the large central airways.

Adolescent↗

The effect of thymoxamine and cromolyn sodium on postexercise bronchoconstriction in asthma.

Of the 22 patients with extrinsic bronchial asthma, 13 patients developed post-exercise bronchoconstriction after treadmill exercise, whereas in 9 patients treadmill exercise had no effect on the ventilatory capacity. No statistical difference in the resting lung volumes and CO transfer factor was found between the two groups. A significant inhibition of postexercise bronchoconstriction was observed in 12 of 13 patients following thymoxamine or cromolyn sodium inhalation. Inhibition of postexercise bronchoconstriction by alpha blockade with thymoxamine suggests that increased alpha adrenergic activity in the presence of diminished beta receptor responsiveness to catecholamines, norepinephrine released during exercise could have a marked alpha agonistic effect giving rise to bronchoconstriction. It has been suggested that cromolyn sodium has a cyclic phosphodiesterase inhibiting action. This might increase levels of AMP and restore the beta receptor responsiveness to catecholamines.

Airway Obstruction↗

Response of lymphocyte guanyl cyclase to propranolol, noradrenaline, thymoxamine, and acetylcholine in extrinsic bronchial asthma.

The lymphocyte guanyl cyclase response to alpha-agonists was studied in 10 normal people and 12 patients with bronchial asthma. In the normal subjects alpha-adrenergic stimulation with noradrenaline plus propranolol and cholinergic stimulation with acetylcholine evoked significant increases in cyclic guanosine monophosphate formation. In addition the alpha-receptor blocking drug thymoxamine produced a significant stimulation of this enzyme system, and the effects of thymoxamine and acetylcholine were additive. This suggests that receptors for cholinergic and alpha-adrenergic agents are independent. In contrast, lymphocyte guanyl cyclase activity did not show a significant response to these agents in patients with acute asthma. In asthmatic patients in remission the responses were partially restored. The significance of these results for control of bronchomotor tone and the relation of guanyl cyclase activity to cyclic adenosine monophosphate in normal subjects and patients with asthma is discussed.

Acetylcholine↗

Atropine, sodium cromoglycate, and thymoxamine in PGF2 alpha-induced bronchoconstriction in extrinsic asthma.

In six patients with extrinsic bronchial asthma the inhalation of prostaglandin (PG) F2 alpha in a small dosage produced significant bronchoconstriction, whereas PGE2 produced bronchodilatation. In these patients cholinergic blockade with atropine partially inhibited the PGF2 alpha-induced bronchoconstriction, but the alpha-receptor-blocking drug thymoxamine and sodium cromoglycate did not. These results suggest that the effect of PGF2 alpha is mediated through cholinergic receptors in the airways, and this effect is grossly exaggerated in asthma. The failure to inhibit PGF2 alpha-induced bronchoconstriction with sodium cromoglycate and the observation of an inhibitory effect of sodium cromoglycate in both allergic and exercise asthma suggest that locally formed PGF2 alpha may not be the main factor in the pathogenesis of bronchial asthma.

Adolescent↗