651
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Chalasani N, Clark WS, Martin LG, Kamean J, Khan MA, Patel NH, Boyer TD. Determinants of mortality in patients with advanced cirrhosis after transjugular intrahepatic portosystemic shunting. Gastroenterology 2000; 118:138-44. [PMID: 10611162 DOI: 10.1016/s0016-5085(00)70422-7] [Citation(s) in RCA: 148] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
BACKGROUND & AIMS Transjugular intrahepatic portosystemic shunt (TIPS) placement is effective in the treatment of complications of portal hypertension. This study evaluated the predictors of mortality in a group of cirrhotic patients with advanced liver disease after placement of TIPS. METHODS A retrospective analysis of all patients undergoing TIPS placement over a 21/2-year period was undertaken. RESULTS Fifty-six patients had TIPS placement for variceal hemorrhage, 49 for refractory ascites, and 24 for hepatic hydrothorax (total, 129). Of 21 variables available before TIPS placement, variceal hemorrhage requiring emergent TIPS placement (relative risk [RR], 37.5; 95% confidence interval [CI], 5.4-259) and bilirubin concentration > 3.0 mg/dL (RR, 5.4; 95% CI, 1.4-10.2) were independent predictors of 30-day mortality. Variceal hemorrhage requiring emergent TIPS placement (hazard ratio [HR], 5.1, 95% CI, 2. 2-9.1), alanine aminotransferase level > 100 IU/L (HR, 2.5; 95% CI, 1.2-5.5), bilirubin level > 3.0 mg/dL (HR, 2.6; 95% CI, 1.1-4.6), and pre-TIPS encephalopathy unrelated to bleeding (HR, 2.2; 95% CI, 1.2-4.8) independently predicted death during the follow-up period. A model was developed that separated the patients into 3 groups with significantly different survival rates. CONCLUSIONS A clinical index consisting of 4 pre-TIPS variables can reliably predict outcome after TIPS.
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652
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Abstract
Erectile dysfunction (ED) is a common problem with a multifactorial aetiology. The treatment of ED has been revolutionised by the introduction of intracavernosal injections some two decades ago. However, the recent development of the orally-administered drug sildenafil (Viagra) has had a major impact on the treatment of ED. We discuss the trials with sildenafil with special reference to cardiovascular risk factors associated with ED.
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653
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Mikhailidis DP, Khan MA, Milionis HJ, Morgan RJ. The treatment of hypertension in patients with erectile dysfunction. Curr Med Res Opin 2000; 16 Suppl 1:s31-6. [PMID: 11329820 DOI: 10.1185/0300799009117037] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Hypertension is another predictor of erectile dysfunction (ED). This is further evidence supporting a link between the pathogenesis of atherosclerotic disease and ED. In one study (TOMHS) involving hypertensive patients, the incidence of ED was 14.4%. The drugs used to treat hypertension may cause ED. However, there is little trial-based evidence to indicate which drugs are more likely to cause this side effect. In general, thiazide diuretics and beta-blockers seem to cause ED more often. In contrast, the alpha-blocker, doxazosin, has not been associated with an increased incidence of ED as a side effect. Doxazosin also improves urinary flow in patients with benign prostatic hyperplasia (BPH). This condition is common in elderly men as is hypertension and ED. Therefore, doxazosin may present a special advantage among this group of patients. This alpha-blocker would also be a good choice in patients with impaired glucose tolerance/diabetes because it improves insulin sensitivity. Moreover, ED and hypertension are more prevalent among diabetics. On a more speculative note, doxazosin may potentiate the therapeutic impact of specific treatments for ED.
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654
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Khan MA, St Peter JV, Breen GA, Hartley GG, Vessey JT. Diabetes disease stage predicts weight loss outcomes with long-term appetite suppressants. OBESITY RESEARCH 2000; 8:43-8. [PMID: 10678258 DOI: 10.1038/oby.2000.7] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
OBJECTIVES Characterize degree of weight loss with stage of diabetes and describe its effect on cardiovascular disease risk factors in obese patients with and without diabetes. RESEARCH METHODS AND PROCEDURES Retrospective cohort analysis from patients participating in a long-term weight management protocol using diet, exercise, behavioral modification, and appetite-suppressant therapy. Patient groups, with (n = 19) and without diabetes (n = 19) were matched for age, gender, and weight before weight loss therapy. The effect of 12 months of therapy on weight, blood pressure, glycemic control, lipid profile, and medication requirements were tested. Additionally, patients were grouped or staged based upon therapy required for control of diabetes at the beginning of weight loss intervention. Analysis of covariance described relationships between diabetes disease stage and weight loss at 12 months. RESULTS Nondiabetic patients had greater mean reduction in BMI than the diabetic group (7.98 kg/m2 vs. 4.77 kg/m2, p<0.01). A significant linear trend (p<0.001) for decreasing weight loss with stage of diabetes was observed. Blood pressure, lipid profile, and glycemia improved significantly. The average daily glyburide-equivalent dose decreased from 9.4 to 3.0 mg (p<0.01). DISCUSSION Patients with diabetes lost less weight than similarly obese patients without diabetes. Regardless of differential weight loss between groups, cardiovascular disease risk factors improved. Hypoglycemic medication requirements decreased with weight loss therapy. A predictive relationship may exist between diabetes disease stage before weight loss therapy and future weight loss potential.
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655
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Khan MA, Collins AJ, Keane WF. Diabetes in the elderly population. ADVANCES IN RENAL REPLACEMENT THERAPY 2000; 7:32-51. [PMID: 10672916 DOI: 10.1016/s1073-4449(00)70004-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Type 2 diabetes mellitus has emerged as an important condition of older patients in which both microvascular and macrovascular complications are a common cause of morbidity and mortality. In contrast to type 1 diabetes mellitus, this endocrinopathy is clustered in minority populations and has both strong genetic and environmental factors that influence disease manifestation. A number of physiological alterations of glucose metabolism including hepatic overproduction of glucose, and reduced glucose utilization by peripheral tissues as a result of insulin resistance contribute to the development of the metabolic manifestations of this disease. Ultimately, pancreatic failure and reduced insulin secretion lead to hyperglycemia and the diabetic state. Frequently, many of these metabolic manifestations, or what has been termed Syndrome X, antecede the development of overt diabetes by many years. This syndrome is manifest clinically by such cardiovascular risk factors as hypertension, dyslipidemia, and coagulation abnormalities. This abnormal metabolic milieu contributes to the high prevalence of macrovascular complications including coronary artery disease as well as more generalized atherosclerosis. Microvascular complications have only more recently been recognized as an important and frequent complication of type 2 diabetes. Among the elderly and minority populations, this has become the single most important cause of end-stage renal failure that necessitates renal replacement therapies. The outcome for these patients on hemodialysis, the modality most frequently selected, is poor, with the majority of these patients dying of cardiovascular causes. Unfortunately, interventional strategies to reduce or prevent the microvascular and macrovascular complications have only recently received the needed attention and will require considerable effort and resources to improve the clinical outcomes and life expectancies for these patients.
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656
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Abstract
Over the past two decades our understanding of the physiology and the various mediators involved in the pathway of penile erection has greatly increased. This has enabled us to develop effective pharmacological treatments for ED.
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657
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Mumtaz FH, Khan MA, Sullivan ME, Thompson CS, Mikhailidis DP, Morgan RJ, Dashwood MR. Potential role of endothelin and nitric oxide in physiology and pathophysiology of the lower urinary tract. ENDOTHELIUM : JOURNAL OF ENDOTHELIAL CELL RESEARCH 1999; 7:1-9. [PMID: 10599556 DOI: 10.3109/10623329909165307] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Endothelium-derived vasoactive mediators (endothelin-1 with its vasoconstrictive and mitogenic properties and nitric oxide with its vasodilatory and antiproliferative properties) play an important role in the regulation of vascular smooth muscle tone and cellular proliferation. Several recent studies have now demonstrated the presence of these vasoactive agents in the urinary tract where they are thought to play a prominent role in urinary tract physiology and disease. This article reviews the synthesis, localisation and actions of endothelin and nitric oxide in the lower urinary tract and examines the possible role of these mediators in disease.
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658
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Khan MA, Dashwood MR, Thompson CS, Mumtaz FH, Mikhailidis DP, Morgan RJ. Up-regulation of endothelin (ET(A) and ET(B)) receptors and down-regulation of nitric oxide synthase in the detrusor of a rabbit model of partial bladder outlet obstruction. UROLOGICAL RESEARCH 1999; 27:445-53. [PMID: 10651133 DOI: 10.1007/s002400050134] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Bladder outlet obstruction (BOO) is associated with altered bladder structure and function. Endothelin-1 (ET-1) has mitogenic and potent contractile properties. There are two ET receptors: ET(A) and ET(B). Nitric oxide synthase (NOS) is the enzyme responsible for the synthesis of nitric oxide (NO) which is involved in smooth muscle relaxation. We investigated whether there are any changes in the density of ET-receptors and NOS in the detrusor and bladder neck in a rabbit model of BOO. Partial BOO was induced in adult male New Zealand White rabbits. Sham operated age-matched rabbits acted as controls. After six weeks the urinary bladders were excised and detrusor and bladder neck sections incubated with radioligands for ET-1, ET(A) and ET(B) receptors and with [3H]-1-NOARG (a ligand for NOS). NADPH histochemistry was also performed. BOO bladder weights were significantly increased (P = 0.002). ET-1 binding and ETA receptor binding sites were significantly increased in the BOO detrusor smooth muscle (P = 0.04, P = 0.03 respectively) and urothelium (P = 0.002, P = 0.02 respectively). ET(B) receptor binding sites were also significantly increased in the BOO detrusor smooth muscle (P = 0.04). However, there was no change in the BOO bladder neck. NOS was significantly decreased in the detrusor smooth muscle (P = 0.003) and urothelium (P = 0.0002). In the bladder neck NOS was also significantly reduced in the urothelium (P = 0.003). NADPH staining was decreased in the detrusor and bladder neck. The up-regulation of ET receptors along with the down-regulation of NOS in the detrusor may contribute to the symptoms associated with BOO. Since ET-1 has a mitogenic role, especially via its ETA receptors, the increase in ETA receptors may also be involved in detrusor hyperplasia and hypertrophy in BOO. ET antagonists may therefore have a role in the treatment of patients with BOO.
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659
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Mumtaz FH, Thompson CS, Khan MA, Mikhailidis DP, Morgan RJ, Angelini GD, Jeremy JY. Alterations in the formation of cyclic nucleotides and prostaglandins in the lower urinary tract of the diabetic rabbit. UROLOGICAL RESEARCH 1999; 27:470-5. [PMID: 10651136 DOI: 10.1007/s002400050137] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/14/2023]
Abstract
Dysfunction of the urinary bladder is a recognised complication of diabetes mellitus (DM) which has been attributed, in part, to a direct effect on bladder smooth muscle tissue. The objective of this study was to investigate the effect of alloxan-induced DM on endogenous modulators of smooth muscle tone such as cyclic AMP (cAMP), cyclic GMP (cGMP) and prostaglandins. Male New Zealand white rabbits were rendered diabetic (hyperosmolar, non-ketotic) with an i.v. injection of alloxan. After 6 months, the urinary bladders and urethrae were excised, cut into segments, incubated with stimulators and the formation of prostaglandins (PG), cAMP and cGMP measured using radioimmunoassays. PGE2 and PGI2 formation was impaired in response to arachidonic acid stimulation, whereas it was increased in response to acetylcholine in DM detrusor, bladder neck and urethra compared to controls. Cyclic AMP and cGMP formation in response to forskolin and sodium nitroprusside, respectively, was significantly reduced in the DM tissues of the lower urinary tract compared to the control. Alterations in the formation of prostaglandins, cAMP and cGMP by the smooth muscle of DM lower urinary tract suggests that these biochemical mediators may have a pathophysiological role in the urinary bladder dysfunction associated with DM.
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660
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Khan MA, Dashwood MR, Thompson CS, Mumtaz FH, Mikhailidis DP, Morgan RJ. Time-dependent up-regulation of endothelin-A receptors and down-regulation of endothelin-B receptors and nitric oxide synthase binding sites in the renal medulla of a rabbit model of partial bladder outlet obstruction: potential clinical relevance. BJU Int 1999; 84:1073-80. [PMID: 10571639 DOI: 10.1046/j.1464-410x.1999.00320.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To assess the density of endothelin (ET) receptors (ET-1 is a potent vasoconstrictor peptide acting on two known receptors, ETA and ETB ) and nitric oxide synthase (NOS) binding sites in the kidney of a rabbit model of bladder outlet obstruction (BOO). MATERIALS AND METHODS Partial BOO was created in adult New Zealand White rabbits; after 1, 3, 4 and 6 weeks of BOO, kidney sections were incubated with radioligands for ET-1, ETA, ETB receptors and with [3H]-NOARG (a ligand for NOS). Autoradiographs were generated and analysed densitometrically. Sections were also assessed by NADPH histochemistry. Plasma creatinine, urea and electrolyte levels were regularly monitored. The control and 6-week BOO kidneys were also evaluated ultrastructurally by electron microscopy. RESULTS There was no significant change in plasma creatinine, urea and electrolyte levels. ETA and ETB receptor density was significantly greater in the medulla than in the cortex (P<0.001) in all animals. There was an up-regulation of ETA receptors (P=0.03) and down-regulation of ETB receptors (P=0.03) and NOS binding sites (P<0.001), as well as decreased NADPH staining in the medulla of 6-week partial BOO kidneys. Electron microscopy detected glomerular disruption of the obstructed kidneys. CONCLUSION The time-dependent changes in ETA and ETB receptors, NOS binding sites and NADPH staining in the renal medulla, as well as ultrastructural changes, occur despite normal renal function. These changes appear to be an early event and may play a role in the development of renal failure. Hence, the use of ETA receptor antagonists at this early stage may prevent the development of renal failure/impairment in BOO.
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661
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Bennett WP, Alavanja MC, Blomeke B, Vähäkangas KH, Castrén K, Welsh JA, Bowman ED, Khan MA, Flieder DB, Harris CC. Environmental tobacco smoke, genetic susceptibility, and risk of lung cancer in never-smoking women. J Natl Cancer Inst 1999; 91:2009-14. [PMID: 10580025 DOI: 10.1093/jnci/91.23.2009] [Citation(s) in RCA: 117] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND Exposure to environmental tobacco smoke (ETS) is considered to be a major lung cancer risk factor for never smokers. We investigated the hypothesis that never-smoking women who are exposed to ETS and develop lung cancer are a genetically susceptible population. METHODS Archival tumor tissues were analyzed from 106 never-smoking women enrolled in a case-control study of ETS (and other personal and environmental factors) and lung cancer risk. We analyzed germline polymorphisms in genes that have been associated with cancer susceptibility and whose products activate (cytochrome P450 1A1 [CYP1A1]) and detoxify (glutathione S-transferases M1 [GSTM1] and T1 [GSTT1]) chemical carcinogens found in tobacco smoke. RESULTS When compared with never smokers who had no ETS exposure and developed lung cancer (n = 55), never smokers with exposure to ETS who developed lung cancer (n = 51) were more likely to be deficient in GSTM1 activity (i.e., were GSTM1 null) because of a genetic polymorphism in the GSTM1 gene (odds ratio = 2.6; 95% confidence interval = 1.1-6.1). A statistically significant rising trend in risk occurred with increasing ETS exposure (two-sided P =. 02), reaching a more than sixfold excess risk in those exposed to 55 pack-years of ETS (ETS pack-year = ETS produced by an active smoker, within a confined space such as a room, who smokes one pack of cigarettes a day for a year). No evidence was found of associations between GSTT1 deficiency or the CYP1A1 valine variant and lung cancer risk due to ETS exposure. CONCLUSIONS A common genetic polymorphism divides the population of never smokers into two groups of approximately equal size, one (homozygous carriers of the GSTM1 null allele) that has a statistically significant greater risk of lung cancer from ETS than the other (heterozygous or homozygous carriers of the wild-type GSTM1 allele).
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662
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Khan MA, Thompson CS, Angelini GD, Morgan RJ, Mikhailidis DP, Jeremy JY. Prostaglandins and cyclic nucleotides in the urinary bladder of a rabbit model of partial bladder outlet obstruction. Prostaglandins Leukot Essent Fatty Acids 1999; 61:307-14. [PMID: 10670693 DOI: 10.1054/plef.1999.0105] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Bladder outlet obstruction (BOO) is a common disorder that is associated with altered bladder structure and function. For example, it is well established that BOO results in hypertrophy and hyperplasia of the bladder smooth muscle as well as detrusor instability. Since prostaglandins (PGs) and cyclic nucleotides (cyclic AMP [cAMP] and cyclic GMP [cGMP]) mediate both smooth muscle tone and proliferation, it is reasonable to suggest that changes in their levels may be involved in the pathophysiology of BOO-associated bladder disorders. Hence, the objective of this study was to investigate cyclic AMP, cyclic GMP and prostaglandins in the bladder of a rabbit model of BOO. BOO was induced in adult male New Zealand White rabbits. After 3 weeks, urinary bladders were excised, weighed and cut into segments. They were then incubated with stimulators of PGs, cAMP and cGMP and the formation of PGs, cAMP and cGMP were measured using radioimmunoassays. There was a significant increase in the obstructed bladder weights (P=0.002). The formation of PGE2, PGI2, cAMP and cGMP was significantly diminished in the detrusor (P<0.05) and bladder neck (P<0.05) in the BOO bladders compared to age-matched controls. Since PGE2, PGI2, cAMP and cGMP are known to inhibit the proliferation of smooth muscle cells (SMCs), the decreased synthesis of these factors, in BOO, may play a role in bladder SMC hypertrophy/hyperplasia. Our study points to the possible use of drugs that modulate the NO-cGMP and/or PG-cAMP axes in BOO-associated bladder pathology.
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663
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Khan MA, Morgan RJ, Thompson CS, Mikhailidis DP. Interactions between nitric oxide and endothelin-1 in vessels from hypercholesterolaemic rabbits. Atherosclerosis 1999; 147:201. [PMID: 10577384 DOI: 10.1016/s0021-9150(99)00181-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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664
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Khan MA, Dashwood MR, Mumtaz FH, Thompson CS, Mikhailidis DP, Morgan RJ. Upregulation of endothelin A receptor sites in the rabbit diabetic kidney: potential relevance to the early pathogenesis of diabetic nephropathy. Nephron Clin Pract 1999; 83:261-7. [PMID: 10529633 DOI: 10.1159/000045519] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND/AIM Nephropathy is an important complication of diabetes mellitus (DM). The plasma endothelin 1 (ET-1) levels are increased in DM, and ET-1 may cause deleterious effects on renal function. We, therefore, investigated whether changes in ET receptors occur in the DM rabbit kidney. METHODS Nine adult New Zealand White rabbits were injected with alloxan, of which 6 became diabetic; the other 3 acted as alloxan-treated controls. Six age-matched healthy rabbits served as controls. At 6 months, following cervical dislocation, the kidneys were removed, and sections (cortex and medulla) were incubated with ET(A) and ET(B) radioligands to produce low- and high-resolution autoradiographs. Immunohistochemical localization of ET-1 immunoreactivity was also performed. RESULTS There was greater ET(A) and ET(B) receptor binding in the control (ET(A) p = 0.0003; ET(B) p < 0.0001) and DM (ET(A) p = 0.001; ET(B) p < 0.0001) rabbits in the medulla as compared with the cortex. DM kidneys showed a significant increase in ET(A), but not ET(B), binding in the cortex (p < 0.0001) and in the medulla (p < 0.0001). High-resolution autoradiographs revealed striking [(125)I]-ET-1 receptor binding predominantly to the glomeruli. Immunohistochemistry revealed dense ET-1 immunoreactivity associated with the renal tubules, but the glomeruli exhibited no staining. Alloxan-treated controls had similar results to age-matched controls. CONCLUSION There are regional differences in both ET(A) and ET(B) binding in control and DM kidneys. ET(A) receptor binding sites are increased in the DM kidney (cortex and medulla). ET-1 may act in a paracrine fashion on the glomeruli. These changes may contribute to the pathogenesis of diabetic nephropathy.
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665
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Khan MA, Dashwood MR, Thompson CS, Auld J, Morgan RJ, Mikhailidis DP. Down-regulation of endothelin-B receptor sites in cavernosal tissue of a rabbit model of partial bladder outlet obstruction: potential clinical relevance. World J Urol 1999; 17:290-5. [PMID: 10552146 DOI: 10.1007/s003450050148] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
Abstract
Erectile dysfunction (ED) is a common problem that significantly affects quality of life and psychological well-being. Benign prostatic hyperplasia (BPH) is the commonest known benign proliferative disorder. Recently there has been growing evidence to suggest that patients with high BPH symptom scores have an increased incidence of ED. Endothelin-1 (ET-1) is a potent vasoconstrictor peptide that is thought to play an important role as a modulator of erectile physiology and dysfunction. We investigated whether there were any changes in the penile histology and in the density and distribution of ET-1 and its receptor subtypes in the corpora cavernosa of a rabbit model of partial bladder outflow obstruction (BOO). BOO was induced in 12 adult New Zealand White rabbits; 12 sham-operated rabbits acted as controls. Penises were excised after 3 and 6 weeks (n=6 each for control and BOO). Low- and high-resolution autoradiography was performed using radioligands for ET-1, ET(A) and ET(B) receptors and the results were analysed densitometrically. Ultrastructural evaluation of the corpus cavernosum (CC) was also performed. ET-1, ET(A) and ET(B) receptor-binding sites were primarily localised to the smooth-muscle cells (SMC) of the CC and to the endothelium lining the cavernosal space. ET(B) receptor-binding sites were significantly decreased (P=0.04) in the 6-week BOO cavernosal tissue. These receptor changes were accompanied by ultrastructural changes in the CC. ET-1 may play a role in the pathophysiology of ED associated with BPH. This may partly be due to enhanced vasoconstrictor actions and SMC proliferation secondary to a reduction in ET(B) receptors. Further work is needed to evaluate this possibility.
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666
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West JA, Dakhama A, Khan MA, Vedal S, Hegele RG. Community study using a polymerase chain reaction panel to determine the prevalence of common respiratory viruses in asthmatic and nonasthmatic children. J Asthma 1999; 36:605-12. [PMID: 10524544 DOI: 10.3109/02770909909087298] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
We developed a sensitive polymerase chain reaction (PCR) panel, suitable for the detection of seven common respiratory viruses, to study the prevalence of viruses in nasal swabs obtained from clinically stable asthmatic children (n = 21), non-physician diagnosed asthmatic children with exercise-induced bronchoconstriction (EIB) (n = 16), and nonasthmatic, non-EIB controls (n = 33). The PCR panel detected viruses in 43/70 (61.4%) specimens but there were no significant differences in prevalence of these viruses between the three groups of children. These results indicate that clinically stable asthmatic and nonasthmatic children frequently harbor viruses in the upper respiratory tract.
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667
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Khan MA, Dashwood MR, Thompson CS, Mumtaz FH, Morgan RJ, Mikhailidis DP. Time-dependent up-regulation of neuronal 5-hydroxytryptamine binding sites in the detrusor of a rabbit model of partial bladder outlet obstruction. World J Urol 1999; 17:255-60. [PMID: 10552140 DOI: 10.1007/s003450050142] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Serotonin (5-hydroxytryptamine; 5-HT), a vasoactive bioamine with potent contractile activity, is thought to act indirectly in the urinary bladder by the stimulation of its presynaptic receptors. This results in the release of acetylcholine (ACh), which then acts on muscarinic receptors to produce bladder contractility. Bladder outlet obstruction (BOO) can lead to detrusor instability associated with denervation supersensitivity to ACh. Using a rabbit model of partial BOO, we investigated whether there were any associated changes in the neuronal 5-HT binding sites. Partial BOO was induced in adult male New Zealand White rabbits. Sham-operated age-matched rabbits acted as controls. After 1, 3 and 6 weeks the urinary bladders were excised. Detrusor sections were incubated with [(3)H]-5-HT. Autoradiographs were generated and analysed densitometrically. The presence of nerves was detected using immunohistochemistry with NF200. Autoradiography demonstrated a time-dependent, significant (P < 0.0001) up-regulation of [(3)H]-5-HT binding sites in the detrusor smooth muscle after the induction of BOO. Immunohistochemistry confirmed that the [(3)H]-5-HT binding sites were neuronal. In the rabbit model of partial BOO there was a significant time-dependent up-regulation of neuronal [(3)H]-5-HT binding sites in the detrusor. This change may influence 5-HT-mediated ACh release, resulting in increased bladder contractility. This, in turn, may play a role in detrusor instability associated with denervation post-junctional supersensitivity. These results provide a possible rationale for further investigation into the use of 5-HT antagonists in the treatment of detrusor instability associated with BOO.
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668
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Javid G, Gulzar GM, Khan B, Shah A, Khan MA. Percutaneous sonography-guided fine needle aspiration biopsy of colonoscopic biopsy-negative colonic lesions. Indian J Gastroenterol 1999; 18:146-8. [PMID: 10531714] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
BACKGROUND Pre-operative tissue diagnosis with colonoscopy is not always possible in patients with colonic lesions. OBJECTIVE To study the usefulness and efficacy of percutaneous ultrasound-guided aspiration biopsy of colonic lesions. METHODS Fifty consecutive patients with colonic lesions in whom colonoscopic brush cytology and biopsy were either negative or the lesion was not accessible on colonoscopy on two attempts, underwent percutaneous ultrasound-guided fine-needle aspiration biopsy. The results were compared with surgical findings. RESULTS Fine-needle aspiration biopsy revealed adenocarcinoma in 40 patients; one had lymphoma, 2 had tuberculosis, 2 had abscess and 5 patients had negative aspiration. Forty-eight patients (excluding 2 with tuberculosis) underwent laparotomy and the diagnoses on aspiration biopsy were confirmed. Of the 5 negative aspirations, 3 had adenocarcinoma, one had tuberculosis and one intussusception. Thus, we had sensitivity of 91.8%, specificity of 100%, predictive value of positive results 100%, predictive value of negative results 20%, and percentage of false negative results 8.1%. Two patients developed complications--hemorrhage into the peritoneum and sepsis due to perforation at the site of aspiration; both survived after surgery. CONCLUSION Percutaneous ultrasound-guided aspiration biopsy may be attempted for diagnosis of colonic lesions in situations where it may be the only means of obtaining a cytological diagnosis before surgery.
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Khan MA, Thompson CS, Mikhailidis DP, Morgan RJ. The effects of long-term oral L-arginine on the erectile response of rabbits with alloxan-induced diabetes. BJU Int 1999; 84:749. [PMID: 10610249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
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670
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Khan MA, Thompson CS, Emsley AM, Mumtaz FH, Mikhailidis DP, Angelini GD, Morgan RJ, Jeremy JY. The interaction of homocysteine and copper markedly inhibits the relaxation of rabbit corpus cavernosum: new risk factors for angiopathic erectile dysfunction? BJU Int 1999; 84:720-4. [PMID: 10510122 DOI: 10.1046/j.1464-410x.1999.00253.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVES To explore whether homocysteine (HCy), an independent risk factor for atherosclerosis (the angiopathic effect of which occurs through the generation of superoxide anions and hydrogen peroxide, augmented by copper, the superoxide anions reacting with nitric oxide, NO, to produce peroxynitrite, a highly angiopathic free radical) and copper contribute to erectile dysfunction (ED) through similar mechanisms, by assessing their interactive effects on the relaxation of corpus cavernosum using organ-bath techniques. MATERIALS AND METHODS Cavernosal smooth muscle strips were obtained from adult New Zealand White rabbits and mounted in organ baths. After precontraction with phenylephrine (100 micromol/L), relaxation responses to carbachol or sodium nitroprusside (SNP) were assessed in the presence or absence of HCy and copper. The effects of HCy and copper in the presence of superoxide dismutase or catalase were also investigated. RESULTS HCy alone inhibited carbachol-stimulated (NO-dependent) but not SNP-stimulated relaxations (NO-independent). This effect of HCy was significantly augmented by copper, which alone had no effect. The combined effect of HCy and copper was significantly (P<0.05) reversed by superoxide dismutase or catalase. CONCLUSIONS HCy inhibited NO-mediated cavernosal smooth muscle relaxation, an effect that was potentiated by copper and reversed by superoxide dismutase or catalase. It is therefore proposed that the effect of HCy on cavernosal smooth muscle relaxation is mediated by an interaction between NO and superoxide anions. Moreover, HCy may constitute a new risk factor for angiopathic ED.
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671
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Khan MA, Dashwood MR, Thompson CS, Mumtaz FH, Mikhailidis DP, Morgan RJ. Up-regulation of endothelin-B (ETB) receptors and ETB receptor-mediated rabbit detrusor contraction in partial bladder outlet obstruction. BJU Int 1999; 84:714-9. [PMID: 10510121 DOI: 10.1046/j.1464-410x.1999.00248.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To investigate, in a rabbit model of bladder outlet obstruction (BOO), whether ETB receptors initiate any contractile activity, and to assess the density of these receptors. MATERIALS AND METHODS Partial BOO was produced in male New Zealand White rabbits, with age-matched sham-operated rabbits acting as controls. One and 3 weeks later, the detrusor and bladder neck strips were incubated in organ baths with either BQ788 (an ETB antagonist), BQ123 (an ETA antagonist) or vehicle. Concentration-response curves were constructed using IRL-1620 (a selective ETB agonist). Low-resolution autoradiography was performed on serial detrusor and bladder neck sections from control and partial BOO (3-week) rabbits using radioligands for ETA and ETB. RESULTS In strips from controls and after 1 week of partial BOO, IRL-1620 induced no contractions, but after 3 weeks of BOO, IRL-1620 induced significant concentration-dependent detrusor contractions (producing 12%, 25% and 70% of the KCl response at 10-8, 10-7 and 10-6 mol/L, respectively). The ETA antagonist had no effect on IRL-1620-mediated contractions. In contrast, the ETB antagonist completely abolished these contractions. Autoradiography showed the presence of ETA and ETB receptors in the detrusor and bladder neck of normal and obstructed animals, and a significant up-regulation of ETA and ETB receptors only in the obstructed detrusor smooth muscle. CONCLUSIONS In BOO, ETB receptors initiate detrusor contractile activity. This is a time-dependent process that may depend on the up-regulation of ETB receptors in the detrusor. Therefore, ETB receptors may play a role in the pathophysiology of partial BOO.
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672
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Marrogi AJ, Khan MA, Vonderheid EC, Wood GS, McBurney E. p53 tumor suppressor gene mutations in transformed cutaneous T-cell lymphoma: a study of 12 cases. J Cutan Pathol 1999; 26:369-78. [PMID: 10551408 DOI: 10.1111/j.1600-0560.1999.tb01860.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The transformation of cutaneous T-cell lymphoma (t-CTCL) is an uncommon phenomenon that is associated with histopathologic changes and follows an aggressive course. The factors contributing to this transformation are poorly understood. The aim of this study was to analyze the p53 status in t-CTCL and to correlate it with disease outcome. The p53 status was investigated by immunohistochemistry, single-strand conformation polymorphism (SSCP) and DNA sequencing in 12 patients with t-CTCL. Eight mutations were detected; including four in exon 5, one in exon 6 and three in exon 7. Five were point mutations and three were deletions. Paired samples from nontransformed patch and plaque lesions showed no p53 over-expression. Eight disease-related deaths were reported, six to 23 months after transformation, all of which had p53 mutations. Three other patients with wild phenotype (WT-p53) were last reported alive with the disease 19-33 months after transformation (p < 0.0002). One other case had a p53 mutation but a short period of follow-up. Our results suggest that phenotypic changes of t-CTCL are frequently associated with genotype alterations in the p53 gene. Because 70% of the mutations detected were either G to C transversions or deletions, nucleotide-pairing mismatch and not DNA damage by UVB represents a likely mechanism for mutagenesis. Furthermore, the data may help in the design of gene transfer therapies that target the p53 molecule.
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MESH Headings
- Adult
- Aged
- Aged, 80 and over
- Cell Transformation, Neoplastic/chemistry
- Cell Transformation, Neoplastic/genetics
- Cell Transformation, Neoplastic/pathology
- Child, Preschool
- DNA, Neoplasm/analysis
- Female
- Genes, p53
- Humans
- Immunoenzyme Techniques
- Lymphoma, T-Cell, Cutaneous/chemistry
- Lymphoma, T-Cell, Cutaneous/genetics
- Lymphoma, T-Cell, Cutaneous/mortality
- Lymphoma, T-Cell, Cutaneous/pathology
- Male
- Middle Aged
- Models, Molecular
- Molecular Structure
- Mutation
- Polymerase Chain Reaction
- Polymorphism, Single-Stranded Conformational
- Sequence Analysis, DNA
- Skin Neoplasms/chemistry
- Skin Neoplasms/genetics
- Skin Neoplasms/mortality
- Skin Neoplasms/pathology
- Survival Rate
- Tumor Suppressor Protein p53/analysis
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673
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al-Kanhal MA, al-Mohizea IS, al-Othaimeen AI, Khan MA. Nutritive value of various breads in Saudi Arabia. Int J Food Sci Nutr 1999; 50:345-9. [PMID: 10719565 DOI: 10.1080/096374899101076] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
The nutritive value of nine Saudi breads prepared from wheat, millet and corn were measured chemically by proximate, minerals and vitamins analyses. On fresh weight basis, the bread contained 26.4-44.7% moisture, 6.6-10.4% protein, 0.4-2.4% fat, 40.2-60.6% available carbohydrates, 1.8-5.7% dietary fibre, 0.6-2.4% ash and 190-273 Kcal (metabolizable) per 100 g. All the breads were low in Ca (2.2-12.5 mg/100 g), P ranged from 41.9-320.8, Na 83.2-794.6, K 0.7-224.2 and Fe 1.6-7.8 mg/100 g. The contents of vitamin A (RE), thiamin and riboflavin ranged from 0-145 micrograms, 0.01-0.26 mg, 0.02-0.13 mg/100 g respectively. The bread contributed 12-18, 2-8 and 77-84% of the total food energy from protein, fat and carbohydrates respectively. Wheat bread (355 g/head/day) provided 45 and 61% of energy and protein requirements respectively at national level per person per day.
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674
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Sullivan ME, Thompson CS, Dashwood MR, Khan MA, Jeremy JY, Morgan RJ, Mikhailidis DP. Nitric oxide and penile erection: is erectile dysfunction another manifestation of vascular disease? Cardiovasc Res 1999; 43:658-65. [PMID: 10690337 DOI: 10.1016/s0008-6363(99)00135-2] [Citation(s) in RCA: 167] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
There is convincing evidence that the prevalence of erectile dysfunction is increased among men with ischaemic heart disease. This association may be attributed to the fact that both erectile dysfunction and ischaemic heart disease share similar risk factors (e.g. hypertension, dyslipidaemia, diabetes and smoking). Nitric oxide (NO) activity is adversely affected, in penile and vascular tissue, by these risk factors. It is therefore not surprising that a defect in NO activity is thought to play a role in the pathogenesis of both erectile dysfunction and ischaemic heart disease. We consider this evidence and propose that defective NO activity provides a unifying explanation for the association between these two conditions. Further research in this area may improve our understanding of the pathogenesis of cardiovascular diseases as a whole.
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675
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Khan MA, Thompson CS, Mikhalidis DP, Morgan RJ. Histopathological changes and nitric oxide synthase activity in corpus cavernosum from rats with neurogenic erectile dysfunction. BJU Int 1999; 84:387. [PMID: 10507894] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
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