asif mahmood - Academia.edu (original) (raw)

Papers by asif mahmood

Journal of Vascular Surgery, 2002

Background: To evaluate the efficacy of a modification of the composite sequential femorocrural b... more Background: To evaluate the efficacy of a modification of the composite sequential femorocrural bypass graft that we adopted in 1985, a retrospective case-note study was undertaken. The grafts combined a prosthetic femoropopliteal section with a popliteal to crural section with autologous vein, linked via a common intermediate anastomosis sited on the above-knee popliteal artery. Patients and methods: Between 1985 and 2000, 68 grafts of this type were constructed in 65 patients with critical ischemia of the lower limb and insufficient autologous vein for construction of an all venous bypass. Reasons for insufficient long saphenous vein included previous lower limb bypass in 33 cases, phlebitis in 16 cases, venous hypoplasia in eight cases, and previous varicose vein surgery in seven cases. Distal anastomoses were carried out to the peroneal artery in 26 cases, the anterior tibial artery in 17 cases, the posterior tibial artery in 17 cases, and the pedal arteries in eight cases. Sources of vein included the long saphenous vein in 26 cases, the arm vein in 38 cases, and the short saphenous vein in two cases. In 22 limbs (32%), angiography had shown an occluded segment of above-knee popliteal artery, and in these cases, local popliteal disobliteration was performed to receive the composite anastomosis and to provide additional outflow. Results: The 2-year cumulative primary patency, secondary patency, and limb salvage rates were 68%, 73%, and 75%, respectively. Localized popliteal disobliteration did not compromise graft patency (P ‫؍‬ .07, with log-rank test). Conclusion: In the absence of sufficient autologous vein, patients needing bypass to crural arteries can be offered reconstruction with composite sequential grafting with satisfactory results. Furthermore, an occluded above-knee popliteal segment is not a contraindication for composite sequential bypass reconstruction. (J Vasc Surg 2002;36:

Journal of Vascular Surgery, 2003

Management of asymptomatic popliteal aneurysm is controversial, and the prognosis for acutely thr... more Management of asymptomatic popliteal aneurysm is controversial, and the prognosis for acutely thrombosed aneurysm is notoriously poor. We evaluated the management and outcome for popliteal aneurysm. A retrospective review of all patients with popliteal aneurysm between 1988 and 2000 was carried out. Fifty-two limbs were operated on in 41 patients. Data collected included findings at presentation, operative details, graft patency, limb salvage, complications, and 30-day mortality. Initial findings included acute ischemia (n = 14), no symptoms (n = 29), acute rupture (n = 2), chronic ischemia (n = 5), and symptoms of nerve or vein compressive (n = 2). All patients with symptomatic aneurysms and 22 patients with asymptomatic aneurysms (21 larger than 2 cm in diameter, 1 with thrombus at duplex ultrasound scanning) underwent surgery as first-line treatment. Of the 7 patients with asymptomatic aneurysm managed with surveillance with duplex ultrasound scanning, acute ischemia developed in three, 1 aneurysm ruptured, compressive symptoms developed in 1, and 2 remained asymptomatic but required surgery because of aneurysm enlargement (>2 cm). Of the 17 patients with acute ischemia, 13 had neurologic signs and underwent immediate thromboembolectomy (trifurcation alone in 8, ankle-level arteriotomy in 4) and bypass grafting (n = 12) or inlay grafting (n = 1), and the other 4 underwent intra-arterial thrombolysis initially. Of these 4 procedures, 2 were successful and had elective surgery; the other 2 required urgent surgery because of secondary distal embolism and failure of recanalization. Thirteen of the 17 grafts were to the crural vessels. Bypass grafting (medial approach) was used in 16 of the 17 patients with acute ischemia, all 5 patients with chronic ischemia, and the 8 patients with no symptoms. An inlay technique (posterior approach) was used in 16 patients with no symptoms, the 3 patients with symptoms of nerve or vein compression, and 1 patient with acute ischemia. The distal anastomoses were to the below-knee popliteal artery in 35 patients and the crural arteries in 15 patients, using autologous vein. Two of the patients with rupture underwent ligation alone, the other undergoing bypass grafting in addition. The overall 5-year primary patency rate was 69%, secondary patency rate was 87%, and limb salvage rate was 87%. Limb salvage was achieved in 14 of the 17 patients with acute ischemia. Patients with asymptomatic aneurysms had better secondary graft patency (100%) compared with symptomatic aneurysms (74%; P <.01). Acute ischemia, technique used, and crural artery grafts were not predictors of graft failure with either univariate or multivariate analysis. Symptomatic aneurysms were associated with more postoperative complications and greater 30-day mortality (4 of 28 vs 0 of 24). Thromboembolectomy followed by crural bypass grafting is an effective treatment for popliteal aneurysm with severe acute limb ischemia. Outcome is better with surgical management of asymptomatic popliteal aneurysm compared with symptomatic aneurysm.

Alimentary Pharmacology & Therapeutics, 2005

Background : Current treatment of ulcerative colitis is imperfect. Trefoil peptides are known to ... more Background : Current treatment of ulcerative colitis is imperfect. Trefoil peptides are known to stimulate repair in many models of injury, including animal models of colitis.Aim : To assess the efficacy of trefoil factor family-3 enema treatment in a clinical trial.Methods : A total of 16 patients with mild-to-moderate left sided ulcerative colitis were recruited into a double-blind randomized placebo-controlled study. Patients taking steroids or with proctitis only were excluded. Patients received 75 mL enemas containing either human recombinant trefoil factor family-3 (10 mg/mL) or saline alone once a day for 14 days. All patients also received an oral dose-increment of 1.2 g of mesalazine daily above their normal usage. Patients were assessed at 0, 2, 4 and 12 weeks. Remission was defined as Ulcerative Colitis Disease Activity Index of 0 or 1 with no blood in stool. Individual clinical improvement was defined as a Ulcerative Colitis Disease Activity Index reduction of >3. Data was analysed using chi-square test and anova.Results : Median Ulcerative Colitis Disease Activity Index at entry were 8.5 (trefoil factor family-3 group) and 8 (placebo group). Analysed on an intention-to-treat basis, only one patient went into remission (in trefoil factor family-3 group at day 28). Clinical improvement was seen in two trefoil factor family-3 and three placebo patients on day 14 and two patients in each group on day 28.Conclusion : Increasing the dose of 5-aminosalicylic acid was moderately effective in reducing the Ulcerative Colitis Disease Activity Index but was insufficient to induce remission. Trefoil factor family-3 enemas were well-tolerated but did not provide additional benefit above that of adding additional 5-aminosalicylic acid alone.

Current Opinion in Pharmacology, 2004

Peptide growth factors are a fascinating group of molecules with diverse effects. Recent developm... more Peptide growth factors are a fascinating group of molecules with diverse effects. Recent developments have allowed us to gain a much greater insight into their pathophysiological functions. In addition, the development of recombinant peptide technology, monoclonal antibody production and both artificial small molecule receptor agonists and inhibitors now allows us to use these factors for the treatment of multiple conditions including gastrointestinal malignancy (particularly colonic carcinoma), short bowel syndrome (where factors such as growth hormone, epidermal growth factor and glucagons-like peptide 2 show particular promise), and inflammatory bowel disease.

Gut, 2007

Background: Zinc carnosine (ZnC) is a health food product claimed to possess health-promoting and... more Background: Zinc carnosine (ZnC) is a health food product claimed to possess health-promoting and gastrointestinal supportive activity. Scientific evidence underlying these claims is, however, limited. Aim: To examine the effect of ZnC on various models of gut injury and repair, and in a clinical trial. Methods: In vitro studies used pro-migratory (wounded monolayer) and proliferation ([ 3 H]-thymidine incorporation) assays of human colonic (HT29), rat intestinal epithelial (RIE) and canine kidney (MDCK) epithelial cells. In vivo studies used a rat model of gastric damage (indomethacin/restraint) and a mouse model of small-intestinal (indomethacin) damage. Healthy volunteers (n = 10) undertook a randomised crossover trial comparing changes in gut permeability (lactulose:rhamnose ratios) before and after 5 days of indomethacin treatment (50 mg three times a day) with ZnC (37.5 mg twice daily) or placebo coadministration. Results: ZnC stimulated migration and proliferation of cells in a dose-dependent manner (maximum effects in both assays at 100 mmol/l using HT29 cells), causing an approximate threefold increase in migration and proliferation (both p,0.01). Oral ZnC decreased gastric (75% reduction at 5 mg/ml) and small-intestinal injury (50% reduction in villus shortening at 40 mg/ml; both p,0.01). In volunteers, indomethacin caused a threefold increase in gut permeability in the control arm; lactulose:rhamnose ratios were (mean (standard error of mean)) 0.35 (0.035) before indomethacin treatment and 0.88 (0.11) after 5 days of indomethacin treatment (p,0.01), whereas no significant increase in permeability was seen when ZnC was coadministered. Conclusion: ZnC, at concentrations likely to be found in the gut lumen, stabilises gut mucosa. Further studies are warranted.

Journal of Vascular Surgery, 2002

Background: To evaluate the efficacy of a modification of the composite sequential femorocrural b... more Background: To evaluate the efficacy of a modification of the composite sequential femorocrural bypass graft that we adopted in 1985, a retrospective case-note study was undertaken. The grafts combined a prosthetic femoropopliteal section with a popliteal to crural section with autologous vein, linked via a common intermediate anastomosis sited on the above-knee popliteal artery. Patients and methods: Between 1985 and 2000, 68 grafts of this type were constructed in 65 patients with critical ischemia of the lower limb and insufficient autologous vein for construction of an all venous bypass. Reasons for insufficient long saphenous vein included previous lower limb bypass in 33 cases, phlebitis in 16 cases, venous hypoplasia in eight cases, and previous varicose vein surgery in seven cases. Distal anastomoses were carried out to the peroneal artery in 26 cases, the anterior tibial artery in 17 cases, the posterior tibial artery in 17 cases, and the pedal arteries in eight cases. Sources of vein included the long saphenous vein in 26 cases, the arm vein in 38 cases, and the short saphenous vein in two cases. In 22 limbs (32%), angiography had shown an occluded segment of above-knee popliteal artery, and in these cases, local popliteal disobliteration was performed to receive the composite anastomosis and to provide additional outflow. Results: The 2-year cumulative primary patency, secondary patency, and limb salvage rates were 68%, 73%, and 75%, respectively. Localized popliteal disobliteration did not compromise graft patency (P ‫؍‬ .07, with log-rank test). Conclusion: In the absence of sufficient autologous vein, patients needing bypass to crural arteries can be offered reconstruction with composite sequential grafting with satisfactory results. Furthermore, an occluded above-knee popliteal segment is not a contraindication for composite sequential bypass reconstruction. (J Vasc Surg 2002;36:

Journal of Vascular Surgery, 2003

Management of asymptomatic popliteal aneurysm is controversial, and the prognosis for acutely thr... more Management of asymptomatic popliteal aneurysm is controversial, and the prognosis for acutely thrombosed aneurysm is notoriously poor. We evaluated the management and outcome for popliteal aneurysm. A retrospective review of all patients with popliteal aneurysm between 1988 and 2000 was carried out. Fifty-two limbs were operated on in 41 patients. Data collected included findings at presentation, operative details, graft patency, limb salvage, complications, and 30-day mortality. Initial findings included acute ischemia (n = 14), no symptoms (n = 29), acute rupture (n = 2), chronic ischemia (n = 5), and symptoms of nerve or vein compressive (n = 2). All patients with symptomatic aneurysms and 22 patients with asymptomatic aneurysms (21 larger than 2 cm in diameter, 1 with thrombus at duplex ultrasound scanning) underwent surgery as first-line treatment. Of the 7 patients with asymptomatic aneurysm managed with surveillance with duplex ultrasound scanning, acute ischemia developed in three, 1 aneurysm ruptured, compressive symptoms developed in 1, and 2 remained asymptomatic but required surgery because of aneurysm enlargement (>2 cm). Of the 17 patients with acute ischemia, 13 had neurologic signs and underwent immediate thromboembolectomy (trifurcation alone in 8, ankle-level arteriotomy in 4) and bypass grafting (n = 12) or inlay grafting (n = 1), and the other 4 underwent intra-arterial thrombolysis initially. Of these 4 procedures, 2 were successful and had elective surgery; the other 2 required urgent surgery because of secondary distal embolism and failure of recanalization. Thirteen of the 17 grafts were to the crural vessels. Bypass grafting (medial approach) was used in 16 of the 17 patients with acute ischemia, all 5 patients with chronic ischemia, and the 8 patients with no symptoms. An inlay technique (posterior approach) was used in 16 patients with no symptoms, the 3 patients with symptoms of nerve or vein compression, and 1 patient with acute ischemia. The distal anastomoses were to the below-knee popliteal artery in 35 patients and the crural arteries in 15 patients, using autologous vein. Two of the patients with rupture underwent ligation alone, the other undergoing bypass grafting in addition. The overall 5-year primary patency rate was 69%, secondary patency rate was 87%, and limb salvage rate was 87%. Limb salvage was achieved in 14 of the 17 patients with acute ischemia. Patients with asymptomatic aneurysms had better secondary graft patency (100%) compared with symptomatic aneurysms (74%; P <.01). Acute ischemia, technique used, and crural artery grafts were not predictors of graft failure with either univariate or multivariate analysis. Symptomatic aneurysms were associated with more postoperative complications and greater 30-day mortality (4 of 28 vs 0 of 24). Thromboembolectomy followed by crural bypass grafting is an effective treatment for popliteal aneurysm with severe acute limb ischemia. Outcome is better with surgical management of asymptomatic popliteal aneurysm compared with symptomatic aneurysm.

Alimentary Pharmacology & Therapeutics, 2005

Background : Current treatment of ulcerative colitis is imperfect. Trefoil peptides are known to ... more Background : Current treatment of ulcerative colitis is imperfect. Trefoil peptides are known to stimulate repair in many models of injury, including animal models of colitis.Aim : To assess the efficacy of trefoil factor family-3 enema treatment in a clinical trial.Methods : A total of 16 patients with mild-to-moderate left sided ulcerative colitis were recruited into a double-blind randomized placebo-controlled study. Patients taking steroids or with proctitis only were excluded. Patients received 75 mL enemas containing either human recombinant trefoil factor family-3 (10 mg/mL) or saline alone once a day for 14 days. All patients also received an oral dose-increment of 1.2 g of mesalazine daily above their normal usage. Patients were assessed at 0, 2, 4 and 12 weeks. Remission was defined as Ulcerative Colitis Disease Activity Index of 0 or 1 with no blood in stool. Individual clinical improvement was defined as a Ulcerative Colitis Disease Activity Index reduction of >3. Data was analysed using chi-square test and anova.Results : Median Ulcerative Colitis Disease Activity Index at entry were 8.5 (trefoil factor family-3 group) and 8 (placebo group). Analysed on an intention-to-treat basis, only one patient went into remission (in trefoil factor family-3 group at day 28). Clinical improvement was seen in two trefoil factor family-3 and three placebo patients on day 14 and two patients in each group on day 28.Conclusion : Increasing the dose of 5-aminosalicylic acid was moderately effective in reducing the Ulcerative Colitis Disease Activity Index but was insufficient to induce remission. Trefoil factor family-3 enemas were well-tolerated but did not provide additional benefit above that of adding additional 5-aminosalicylic acid alone.

Current Opinion in Pharmacology, 2004

Peptide growth factors are a fascinating group of molecules with diverse effects. Recent developm... more Peptide growth factors are a fascinating group of molecules with diverse effects. Recent developments have allowed us to gain a much greater insight into their pathophysiological functions. In addition, the development of recombinant peptide technology, monoclonal antibody production and both artificial small molecule receptor agonists and inhibitors now allows us to use these factors for the treatment of multiple conditions including gastrointestinal malignancy (particularly colonic carcinoma), short bowel syndrome (where factors such as growth hormone, epidermal growth factor and glucagons-like peptide 2 show particular promise), and inflammatory bowel disease.

Gut, 2007

Background: Zinc carnosine (ZnC) is a health food product claimed to possess health-promoting and... more Background: Zinc carnosine (ZnC) is a health food product claimed to possess health-promoting and gastrointestinal supportive activity. Scientific evidence underlying these claims is, however, limited. Aim: To examine the effect of ZnC on various models of gut injury and repair, and in a clinical trial. Methods: In vitro studies used pro-migratory (wounded monolayer) and proliferation ([ 3 H]-thymidine incorporation) assays of human colonic (HT29), rat intestinal epithelial (RIE) and canine kidney (MDCK) epithelial cells. In vivo studies used a rat model of gastric damage (indomethacin/restraint) and a mouse model of small-intestinal (indomethacin) damage. Healthy volunteers (n = 10) undertook a randomised crossover trial comparing changes in gut permeability (lactulose:rhamnose ratios) before and after 5 days of indomethacin treatment (50 mg three times a day) with ZnC (37.5 mg twice daily) or placebo coadministration. Results: ZnC stimulated migration and proliferation of cells in a dose-dependent manner (maximum effects in both assays at 100 mmol/l using HT29 cells), causing an approximate threefold increase in migration and proliferation (both p,0.01). Oral ZnC decreased gastric (75% reduction at 5 mg/ml) and small-intestinal injury (50% reduction in villus shortening at 40 mg/ml; both p,0.01). In volunteers, indomethacin caused a threefold increase in gut permeability in the control arm; lactulose:rhamnose ratios were (mean (standard error of mean)) 0.35 (0.035) before indomethacin treatment and 0.88 (0.11) after 5 days of indomethacin treatment (p,0.01), whereas no significant increase in permeability was seen when ZnC was coadministered. Conclusion: ZnC, at concentrations likely to be found in the gut lumen, stabilises gut mucosa. Further studies are warranted.