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Biomedical subjects

K R Patel

Publications and source records attributed to K R Patel.

122 records · Page 7Linked to original sources
PubMed1975

Effect of alpha receptor blocking drug, thymoxamine, on allergen induced bronchoconstriction in extrinsic asthma.

In ten patients with extrinsic bronchial asthma, allergen provoked bronchospasm was significantly inhibited by the alpha receptor blocking drug thymoxamine given intravenously. In two of these patients thymoxamine by inhalation also effectively inhibited allergen induced bronchoconstriction. It is suggested that thymoxamine may be acting either by increasing intracellular levels of cyclic AMP and thus inhibiting mediator release following allergen challenge or by modifying the airways response to these mediators by altering the bronchomotor tone. The variable responses recorded after allergen challenge in presence of alpha blockade with thymoxamine suggests that the dominant effect is on the bronchomotor tone rather than the mediator release.

Administration, Intranasal↗
PubMed1974

Response of leucocyte adenyl cyclase to isoprenaline and effect of alpha-blocking drugs in extrinsic bronchial asthma.

The finding by several workers that biochemical responses to catecholamines are diminished in asthmatic patients during periods of active asthma as compared to normal subjects has led to the recognition of the beta-adrenergic blockade phenomenon, a common accompaniment of extrinsic bronchial asthma. Using an intact cell method to measure leucocyte adenyl cyclase activity, we have been able to show that there is a noticeably reduced responsiveness of this enzyme system (which is now identified with beta-receptor function) to isoprenaline in the leucocytes of patients suffering from acute bronchial asthma, but that asthmatic patients in remission could not be distinguished from normal persons in this respect. Evidently the defective beta-receptor function may be associated with overactivity of the alpha-receptors in acute bronchial asthma, since the responsiveness to isoprenaline stimulation could be restored towards normal by concomitant treatment of the leucocytes of these patients with alpha-receptor blocking drugs such as phentolamine or thymoxamine. Ouabain, though somewhat less potent, also enhanced responsiveness to isoprenaline stimulation. The relation of these results to the clinical observation of adrenaline resistance in active asthma suggests that alpha-receptor blocking drugs may be of value in restoring the sensitivity of beta-receptors to sympathomimetic amines.

Acute Disease↗
PubMed1970

Effect of alpha-receptor blocking drugs and disodium cromoglyate on histamine hypersensitivity in bronchial asthma.

Twenty patients with extrinsic type bronchial asthma are shown to have a significant fall in vital capacity (V.C.) and forced expiratory volume in 1 second (F.E.V.(1)) after an intravenous infusion of 50mug. of histamine dihydrochloride. In 10 of these subjects the fall in V.C. and F.E.V.(1) produced by intravenous histamine is inhibited by the alpha-receptor blocking drugs phentolamine and phenoxybenzamine injected before the histamine test. The inhalation of disodium cromoglycate in 10 subjects is also shown to inhibit the fall in V.C. and F.E.V.(1) produced by the intravenous infusion of histamine. It is suggested that bronchial smooth muscle in asthmatic subjects has alpha-adrenergic receptor sites, and that a possible mechanism for the action of disodium cromoglycate is that it stabilizes the cell membrane, thereby altering calcium ion transport.

Adolescent↗
PubMedDate not supplied

True venous aneurysms and arterial "steal" secondary to arteriovenous fistulae for dialysis.

In patients requiring hemodialysis, arteriovenous fistulae may be created using autogenous vessels or prosthetic grafts. Complications of such operations include thrombosis, infection, venous hypertension, pseudoaneurysm, congestive heart failure, true venous aneurysms, and arterial "steal" syndrome. Of these the last two are the least common. On reviewing the English literature (Medline search: 1969-1991) we found only 8 reported cases of true venous aneurysms secondary to creation of an arteriovenous fistulae for dialysis. Hemodynamic assessment has shown that arterial "steal" is frequently present distal to an arteriovenous fistula. However, these patients rarely have ischemic symptoms. Over the last 7 years 236 patients had arteriovenous fistulae created for hemodialysis at our institution. Three of these patients (1.2%) developed true venous aneurysms. One of these 3 patients (0.4%) also had severe hand claudication due to arterial "steal". All of these patients were treated successfully without any complications. The etiology and various therapeutic options for these rare complications are discussed.

Adult↗
PubMedDate not supplied

Herniation of lung.

Non-traumatic, acquired lung hernia of pathologic variety is rare, but can be associated with tuberculous rib osteitis.

Adult↗
PubMedDate not supplied

Bullet embolism.

Bullet embolism is a rare complication of vascular trauma. During the last ten years we have treated six patients with bullet embolism. Three patients had inferior vena caval injuries with embolizations of the bullets to the heart or pulmonary arteries. Two had infrarenal aortic injuries with embolization to vessels of the lower extremities. One patient with a shotgun injury to the superficial femoral artery and vein had both arterial and venous embolizations. The site of vascular penetration was repaired in all six patients. All peripheral arterial bullet emboli were removed except for an asymptomatic shotgun pellet in the peroneal artery. One bullet was removed from a right atrium and another from a proximal pulmonary artery. Emboli in the distal pulmonary artery branches were left undisturbed in two patients. All six patients survived without any complications. A 14-year review of the literature is presented in order to emphasize some important features of this rare pathology.

Adult↗
PubMedDate not supplied

Simultaneous bilateral carotid endarterectomy operations.

Clinical reasoning and sound physiologic data have been the bases for performing bilateral simultaneous carotid endarterectomy operations in 25 patients recently. The results have compared favorably with unilateral carotid endarterectomy operations in 100 patients over the same time span. Thus, there is ample basis for performing operations simultaneously when bilateral carotid endarterectomy operations are indicated.

Adult↗