226
|
Khan MI, Rosberg S, Bergh C, Ahrén K. Desensitization of the cyclic AMP system in rat corpora lutea. Comparison between the effects of hCG and LH. ACTA ENDOCRINOLOGICA 1980; 95:393-403. [PMID: 6254312 DOI: 10.1530/acta.0.0950393] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The changes in hormonal responsiveness of corpora lutea produced by a single injection of hCG or ovine LH were studied in PMSG-treated immature rats with well-characterized corpora lutea of different ages. The hormonal response was measured as LH-stimulated accumulation of cyclic AMP in isolated, whole corpora lutea and, in some experiments, as LH stimulated luteal adenylate cyclase activity. Injection of hCG produced a complete desensitization (refractoriness) of very long duration (4-5 days) as has earlier been found in rats with heavily luteinized ovaries, while the injection of LH in equivalent doses, produced only a partial desensitization of much shorter duration (12-48 h). Morphological observations, after injection of trypan blue to a small number of the rats, showed that follicular growth, ovulation and formation of new corpora lutea could occur after both hCG and LH. The possibility that the corpora lutea which started to respond to LH stimulation 5-7 days after the hCG injection were not the ones originally desensitized by hCG but new corpora lutea, is discussed. The very rapid recovery of the LH sensitivity after desensitization with LH, can, however, not be explained in the same way. It represents a true reversal to the 'normal' hormonal sensitivity of the cells originally desensitized. The marked difference between hCG and LH in these desensitizing experiments is discussed in relation to earlier known differences between these two gonadotrophins, e.g. in binding properties to ovarian receptors and in rate of metabolism in the body.
Collapse
|
227
|
Khan MI, Mathew MK, Balaram P, Surolia A. Fluorescence-polarization studies on binding of 4-methylumbelliferyl beta-D-galactopyranoside to Ricinus communis (castor-bean) agglutinin. Biochem J 1980; 191:395-400. [PMID: 6892494 PMCID: PMC1162229 DOI: 10.1042/bj1910395] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The binding of Ricinus communis (castor-bean) agglutinin 1 to saccharides was studied by equilibrium dialysis and fluorescence polarization by using the fluorescently labelled sugar 4-methylumbelliferyl beta-D-galactopyranoside. No appreciable change in ligand fluorescence of 4-methylumbelliferyl beta-D-galactopyranoside was considerably polarized on its binding to the lectin. The association constants obtained by Scatchard analysis of equilibrium-dialysis and fluorescence-polarization data do not differ much from each other, and at 25 degrees C, Ka = 2.4 (+/- 0.2) X 10(4)M-1. These values agree reasonably well with that reported in the literature for Ricinus agglutinin 1. The number of binding sites obtained by the different experimental procedures is 1.94 +/- 0.1 per molecule of 120 000 daltons and is equal to the reported value of 2. The consistency in the values of Ka and number of binding sites indicate the absence of additional subsites on Ricinus agglutinin 1 for its specific sugars. In addition, the excellent agreement between the binding parameters obtained by equilibrium dialysis and fluorescence polarization indicate the potential of ligand-fluorescence-polarization measurements in the investigation of lectin-sugar interactions.
Collapse
|
228
|
Khan MI, Rosberg S, Lahav M, Lamprecht SA, Selstam G, Herlitz H, Ahrén K. Studies on the mechanism of action of the inhibitory effect of prostaglandin F2 alpha on cyclic AMP accumulation in rat corpora lutea of various ages. Biol Reprod 1979; 21:1175-83. [PMID: 93001 DOI: 10.1095/biolreprod21.5.1175] [Citation(s) in RCA: 34] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
|
229
|
Khan MI. [A practical approach to the tuberculosis problem in Bahrain]. BULLETIN OF THE INTERNATIONAL UNION AGAINST TUBERCULOSIS 1979; 54:150-1. [PMID: 526640] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
|
230
|
Khan MI. Neuromyelitis optica (relapsing type). JPMA. THE JOURNAL OF THE PAKISTAN MEDICAL ASSOCIATION 1976; 26:61-3. [PMID: 180305] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
A case of relapsing type of neuromyelitis optica following influenza-like illness treated successfully with steroids and corticotrophin has been described. Raised gamma-globulin in CSF was suggestive of an autoimmune disorder. Inspite of six relapses in 8 years she has minimal neurological deficit.
Collapse
|
231
|
Herlitz H, Koch Y, Khan MI, Ahrén K. Effect of follicle-stimulating hormone on cyclic AMP levels in young corpora lutea of the rat. Eur J Obstet Gynecol Reprod Biol 1976; 6:175-9. [PMID: 185106 DOI: 10.1016/0028-2243(76)90024-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
|
232
|
Haider B, Khan MI, Burke WM, Regan TJ. Ischemic heart failure: sustained inotropic response to small doses of I-epinephrine without toxicity. Am J Cardiol 1975; 35:504-13. [PMID: 1119401 DOI: 10.1016/0002-9149(75)90833-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
As a prelude to a study of severe ischemic heart failure, the therapeutic response of the ischemic ventricle to epinephrine and acetylstrophanthidin in nontoxic doses was determined in 24 intact anesthetized dogs undergoing a first episode of acute regional ischemia. A thrombotic obstruction was produced in the left ventricular dysfunction. The elevation of end-diastolic pressure and reduced stroke volume in control dogs were not significantly altered by administration of strophanthidin. Epinephrine (0.05 mug/kg per min) elicited a significant reduction in end-diastolic pressure and increase in stroke volume. The latter was not attended by an increased incidence of ventricular fibrillation, whereas fibrillation occurred in half of the group given strophantihidin. Thus, the catecholamine was selected to study pump failure. Severe ischemic heart failure was assessed in two groups with scar from previous infarction for up to 4 hours. By 60 minutes of ischemia the increase in end-diastolic pressure and volume and decrease in stroke volume and ejection fraction were comparable in both groups. Thereafter, alternate animals received small doses of epinephrine (0.05 to 0.15 mug/kg per min) with graded increments at 60 minute intervals to counter tachyphylaxis and findings were compared with those in control dogs. Over the subsequent 3 hours, there was progressive deterioration of left anterior descending coronary artery, affecting ventricular function in the untreated group with an increase in end-diastolic pressure from 10 plus or minus 1 to 33 plus or minus 2.4 mm Hg. End-diastolic volume increased by 63 percent; stroke volume and ejection fraction decreased by 48 and 66 percent, respectively. The infusion of epinephrine was attended by a significantly lower end-diastolic pressure of 20 plus or minus 2.5 mm Hg, whereas end-diastolic volume, stroke volume and ejection fraction were restored to control levels after 4 hours of ischemia. Mortality in the untreated group was 62 percent by 4 hours; all seven animals in the treated group survived.
Collapse
|
233
|
Regan TJ, Khan MI, Ettinger PO, Haider B, Lyons MM, Oldewurtel HA. Myocardial function and lipid metabolism in the chronic alcoholic animal. J Clin Invest 1974; 54:740-52. [PMID: 4368946 PMCID: PMC301608 DOI: 10.1172/jci107812] [Citation(s) in RCA: 86] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
In view of the variables that obscure the pathogenesis of cardiomyopathy, a study was undertaken in mongrel dogs fed ethanol as 36% of calories for up to 22 mo. Both the experimental and control groups maintained body weight, hematocrit, plasma vitamin, and protein levels. Left ventricular function was evaluated in the intact anesthetized dog using indicator dilution for end-diastolic and stroke volume determinations. During increased afterload with angiotensin, the ethanol group exhibited a larger rise of end-diastolic pressure (P<0.01), whereas end-diastolic and stroke volume responses were significantly less than in controls. Preload increments with saline elicited a significantly higher end-diastolic pressure rise in the ethanol group (P<0.01). No hypertrophy, inflammation, or fibrosis was present and it was postulated that the enhanced diastolic stiffness was related to accumulation of Alcian Blue-positive material in the ventricular interstitium. To evaluate myocardial lipid metabolism, [1-(14)C]oleic acid was infused systemically. Plasma specific activity and myocardial lipid uptake were similar in both groups. There was a significantly increased incorporation of label into triglyceride, associated with a reduced (14)CO(2) production, considered the basis for a twofold increment of triglyceride content. In addition, diminished incorporation of [(14)C]oleic acid into phospholipid was observed accompanied by morphologic abnormalities of cardiac cell membranes. Potassium loss and sodium gain, like the lipid alteration, was more prominent in the subendocardium. Thus, chronic ethanol ingestion in this animal model is associated with abnormalities of ventricular function without evident malnutrition, analogous to the preclinical malfunction described in the human alcoholic.
Collapse
|
234
|
Ettinger PO, Regan TJ, Oldewurtel HA, Khan MI. Ventricular conduction delay and asystole during systemic hyperkalemia. Am J Cardiol 1974; 33:876-86. [PMID: 4829370 DOI: 10.1016/0002-9149(74)90635-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
|
235
|
Ettinger PO, Regan TJ, Oldewurtel HA, Khan MI. Ventricular conduction delay and arrhythmias during regional hyperkalemia in the dog. Electrical and myocardial ion alterations. Circ Res 1973; 33:521-31. [PMID: 4127618 DOI: 10.1161/01.res.33.5.521] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Coronary arterial potassium (K
+
) infusion induces RS-T elevation and ventricular arrhythmias. To explore electrical and metabolic events in this model, which simulates ischemia-induced injury currents and rhythm disturbances, isotonic KCl was infused at 0.5-2.0 ml/min into the left anterior descending or the left circumflex coronary artery of 37 intact anesthetized dogs. Conduction was monitored with His and left bundle branch recording catheters and with bipolar electrodes at endocardial and epicardial levels in the perfused zone. RS-T segments rose progressively in the perfused region despite normal coronary blood flow (
85
Kr) some dogs progressed rapidly to multifocal ventricular extrasystoles and ventricular fibrillation (group 1), but others continued for 20 minutes without developing fibrillation (group 2). His-Q and bundle branch conduction times were not altered by regional perfusion, but the QRS complex was locally prolonged. Ventricular extrasystoles were frequently coupled and left bundle branch depolarizations never preceded them, suggesting origin within the myocardium. Intramural electrodes showed increasing delay in the perfused region; epicardial depression was uniformly more profound and preceded significant arrhythmias, often with 2:1 or higher intramural block and slowing sufficient to allow reentry. Epicardial activation preceding endocardial activation was observed during extrasystoles in the perfused zone, further indicating origin within the myocardium. These phenomena were associated with tissue concentrations of K
+
in the outer wall significantly higher than those in the inner wall; and sodium was also significantly elevated. Therefore, it was postulated that reentry from depressed epicardial layers into more normal surrounding tissue constitutes a possible basis for the arrythmias in this model.
Collapse
|
236
|
Khan MI, Hamilton JT, Manning GW. Early arrhythmias following experimental coronary occlusion in conscious dogs and their modification by beta-adrenoceptor blocking drugs. Am Heart J 1973; 86:347-58. [PMID: 4146951 DOI: 10.1016/0002-8703(73)90044-6] [Citation(s) in RCA: 33] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
|
237
|
Khan MI, Hamilton JT, Manning GW. Protective effect of beta adrenoceptor blockade in experimental coronary occlusion in conscious dogs. Am J Cardiol 1972; 30:832-7. [PMID: 4404487 DOI: 10.1016/0002-9149(72)90007-0] [Citation(s) in RCA: 75] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
|
238
|
Moschos CB, Khan MI, Jesrani MU, Oldewurtel HA, Regan TJ. Potentation of thrombolysis by a sulfhydryl inhibitor. Cardiovasc Res 1972; 6:556-61. [PMID: 4263153 DOI: 10.1093/cvr/6.5.556] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
|
239
|
Weisse AB, Senft A, Khan MI, Regan TJ. Effect of nitrate infusions on the systemic and coronary circulations following acute experimental myocardial infarction in the intact dog. Am J Cardiol 1972; 30:362-70. [PMID: 5056847 DOI: 10.1016/0002-9149(72)90566-8] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
|
240
|
Miana GA, Ikram M, Sultana F, Khan MI. The isolation and characterization of erysotrine from the leaves of Erythrina suberosa. LLOYDIA 1972; 35:92-3. [PMID: 5037485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
|
241
|
Moschos CB, Khan MI, Regan TJ. Thrombogenic properties of blood during early ischemic and nonischemic injury. THE AMERICAN JOURNAL OF PHYSIOLOGY 1971; 220:1882-4. [PMID: 5087838 DOI: 10.1152/ajplegacy.1971.220.6.1882] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
|
242
|
Weisse AB, Moschos CB, Passannante AJ, Khan MI, Regan TJ. Relative effectiveness of three antiarrhythmic agents in the treatment of ventricular arrhythmias in experimental acute myocardial ischemia. Am Heart J 1971; 81:503-10. [PMID: 5552051 DOI: 10.1016/0002-8703(71)90366-8] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
|
243
|
Regan TJ, Passannante AJ, Khan MI, Oldewurtel HA, Jesrani MU. Influence of scar on left ventricular performance at the onset of myocardial ischemia: shock versus heart failure. J Clin Invest 1971; 50:534-42. [PMID: 5545119 PMCID: PMC291960 DOI: 10.1172/jci106522] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Obstruction of a major branch of the left coronary artery in a previously normal ventricle is not usually associated with shock, experimentally or clinically. To examine the early hemodynamic alterations which may determine the course of ischemia when myocardial scar exists from previous infarction, 16 animals were successfully studied 9 wk after obstruction of the left circumflex artery. Acute ischemia during thrombus formation in the anterior descending artery of intact anesthetized dogs with scar was compared with animals undergoing the same procedure in the absence of scar (group 1). In the chronic animals, two types of hemodynamic responses were observed. Group 2 was characterized by heart failure usually persisting through 3 hr, and group 3 by a different ventricular volume response and rapidly developing shock. The weight of ischemic and scar areas were comparable and coronary blood flow ((85)Kr method) to the ischemic site was reduced to a similar extent. Animals in groups 1 and 2 remained normotensive and had similar elevations of left ventricular enddiastolic volume (indicator dilution method) during the initial 60 min of ischemia. Group 2 had a significantly larger rise of end-diastolic pressure, presumably related to altered elastic properties associated with scar of subendocardial distribution. Group 3 had a stroke volume decline that was not significantly greater than group 2 and both groups had an initial rise of peripheral vascular resistance. Despite a nearly fourfold increase of left ventricular end-diastolic pressure, there was a significant decline of left ventricular end-diastolic volume in group 3. This preceded the onset of hypotension in group 3, with arterial pressure declining to a greater extent than stroke volume, usually culminating in cardiac standstill. Group 3 was distinguished by the presence of transmural scar, which was postulated to influence contiguous ischemic tissue in diastole so as to diminish ventricular volume. By analogy with the hemodynamics of acute pericardial tamponade, a reflex pathway activated in the myocardium in response to reduced end-diastolic volume has been suggested as a mechanism for the arterial hypotension.
Collapse
|
244
|
Ettinger PO, Khan MI, Regan TJ. A catheter electrode technique for study of left ventricular conduction. J Appl Physiol (1985) 1970; 28:519-23. [PMID: 5437445 DOI: 10.1152/jappl.1970.28.4.519] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
|
245
|
Khan MI. Towards the preparation of highest quality medical professionals. BANGLADESH JOURNAL OF MEDICAL SCIENCE 1970. [DOI: 10.3329/bjms.v9i3.6465] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Training of medical professionals being carried out since centuries, where quality of physician depends upon the quality and accreditation of the training system in place. Quality is the means through which an institution can guarantee, with confidence and certainty that the standards of its educational objectives maintained and enhanced. Quality in higher education is a dynamic process which is the outcome of interaction of multiple factors that determine the state of equilibrium reached at various levels. These include, inter alia, leadership, quality of faculty, quality of students, infrastructure, facilities, research and learning environment, governance, strategic planning, assessment procedures, market forces and several other factors depending upon the type, nature and level of educational processes. Quality Medical Education is a comprehensive concept, which consists of a number of ideas and systematic processes. The basic requirements of Quality Medical Education include a well-planned system of education aimed at achieving the goals and objectives set for it and a comprehensive quality infrastructure for the productive implementation and systematic evaluation of that system. In essence Medical Education has to be of the highest quality to produce doctors capable of giving the highest quality of medical care by not only satisfying the consumers i.e. patients, their families, community and employers but offering a service better than their expectations. Such education will need to adopt more than what is called al Quality culture in the institution. Keywords: Quality control; quality assurance; medical education; accreditation; Ihsan. DOI: 10.3329/bjms.v9i3.6465Bangladesh Journal of Medical Science Vol.09 No.3 July 2010, pp.116-123
Collapse
|
246
|
Ettinger PO, Weisse AB, Khan MI, Levinson GE. Double-outlet right ventricle in an adult with aortic regurgitation. Am J Med 1969; 47:818-24. [PMID: 5352206 DOI: 10.1016/0002-9343(69)90176-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
|
247
|
Regan TJ, Passannante AJ, Oldewurtel HA, Khan MI. Ventricular arrhythmias related to antibiotic usage in dogs. Science 1969; 165:509-10. [PMID: 5793246 DOI: 10.1126/science.165.3892.509] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
In dogs, pretreatment with the macrolide antibiotic tylosin (5 milligrams per day per kilogram of body weight) increased the incidence of ventricular tachycardia and fibrillation during acute myocardial ischemia. Another group received a dose of acetyl strophanthidin which was nontoxic in controls, but which resulted in a ventricular arrhythmia in six of seven animals on antibiotic treatment. Enhancement of loss of potassium ion from the myocardium by the antibiotic was presumed to be related to the altered cardiac rhythm.
Collapse
|
248
|
Countee R, Khan MI, Johnson JB, Graebner JA. Arrhythmogenic effect of the short-acting anesthetic agent thiamylal sodium (Surital) in dogs. THE JOURNAL OF CLINICAL PHARMACOLOGY AND THE JOURNAL OF NEW DRUGS 1967; 7:207-13. [PMID: 5232359 DOI: 10.1002/j.1552-4604.1967.tb00049.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
|
249
|
Khan MI, Johnson JB, Harrison C. Transient atrioventricular block induced by respiration. THE MEDICAL ANNALS OF THE DISTRICT OF COLUMBIA 1966; 35:423-5 passim. [PMID: 5221220] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
|