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Biomedical subjects

A G Patel

Publications and source records attributed to A G Patel.

At least 19 recordsLinked to original sources
PubMed2006

Progressive rise in gut hormone levels after Roux-en-Y gastric bypass suggests gut adaptation and explains altered satiety.

BACKGROUND: Bariatric surgery is the most effective treatment for achieving long-term weight loss in morbidly obese patients. This study investigated prospective changes in gut hormones and metabolic indices after Roux-en-Y gastric bypass (RYGB). METHODS: Six patients were seen before, and at 1, 3 and 6 months after operation. Blood was collected after a 12-h fast and at regular intervals after a mixed 420-kcal meal. Hormonal responses were determined, and comparisons between basal levels and areas under the curve were made. Visual analogue scores were used to assess satiety, hunger and nausea. RESULTS: Mean body mass index decreased from 48.3 kg/m(2) before surgery to 36.4 kg/m(2) 6 months after RYGB. This was accompanied by a decrease in fasting leptin (P < 0.001) and insulin (P = 0.021) levels. At 1, 3 and 6 months after operation, progressively increasing peptide YY (P < 0.001), enteroglucagon (P = 0.045) and glucagon-like peptide 1 (P = 0.042) responses were observed. There was no change in fasting ghrelin levels (P = 0.144). Postprandial satiety was significantly increased by 1 month after surgery and this was maintained until the end of the study (P < 0.001). CONCLUSION: RYGB resulted in substantial weight loss with enhanced postprandial satiety, a sustained weight plateau, and proportionate reduction in fasting insulin and leptin levels. Lack of the expected increase in appetite and food intake as components of a counter-regulatory response may be explained by gut adaptation and the consequent graded rise in the levels of gut hormones that promote satiety.

Adaptation, Physiological↗
PubMed2002

Incidental ultrasound diagnosis of pseudomyxoma peritonei in an asymptomatic woman.

An incidental finding of pseudomyxoma peritonei is reported in a woman with a 6-month history of postmenopausal bleeding. A transvaginal ultrasound scan revealed a poorly defined echogenic mass in the right iliac fossa above the right ovary and free fluid of mixed echogenicity in the pouch of Douglas. Laparoscopic appendicectomy and aspiration of mucinous fluid was performed without adjuvant chemotherapy. Regular postoperative follow-up scans, which are needed as the disease may have an indolent course, showed no signs of recurrence. The differential diagnosis and management of pseudomyxoma peritonei are discussed.

Diagnosis, Differential↗
PubMed2001

Effect of topical glyceryl trinitrate on anodermal blood flow in patients with chronic anal fissures.

INTRODUCTION: Recent studies have highlighted the role of increased internal anal sphincter pressure and decreased anodermal blood flow in the pathogenesis of chronic anal fissures. The duration of the effect of topical 0.2% glyceryl trinitrate (GTN) ointment on anodermal blood flow in fissure and normal areas was investigated in patients with chronic anal fissures. METHODS: Six patients with chronic anal fissures in the posterior midline participated in the study. Blood flow measurements were performed on the anoderm using laser Doppler flowmetry before and immediately after the topical application of 0.2% GTN ointment and subsequent readings were taken at 5, 15, 30, 45 and 60 min in all four quadrants. RESULTS: The mean anodermal blood flow in the fissure region is significantly lower than the mean blood flow of the rest of the anoderm before 0.2% GTN ointment is applied (228.7 +/- 61.8 flux units vs 439.3 +/- 25.5 flux units, respectively; P < 0.05). Immediately after the application of local 0.2% GTN ointment there is a significant increase in anodermal blood flow over the anal fissure region (457.8 +/- 56.5 flux units; P < 0.05) compared to the rest of the anoderm (457.4 +/- 30.8 flux units). This increase is most marked at 5 min post-GTN ointment application in the fissure area (474.6 +/- 41.1 flux units) and the blood flow in the fissure region is consistently above the rest of the anoderm for most of the 60 min. CONCLUSION: There is clearly reduced blood flow to the chronic anal fissure region compared to the rest of the anoderm. Topical application of glyceryl trinitrate ointment seems to significantly improve the blood flow to the fissured area in the first hour. This may therefore help in the healing of chronic anal fissures.

Administration, Topical↗
PubMed2001

Ischaemia/reperfusion contributes to colonic injury following experimental aortic surgery.

OBJECTIVES: ischaemia of the colon is an important complication of abdominal aortic aneurysm (AAA) repair. The aim of this animal study was to investigate the effect of sequential ischaemia and reperfusion on sigmoid mucosal pO2 and its association with local ET-1 release. MATERIAL AND METHODS: twelve pigs underwent colonic ischaemia followed by complete reperfusion. Six other animals were sham controls. A Clark-type microcatheter was used for continuous mucosal pO2 measurements. Serial systemic and inferior mesenteric vein blood samples were obtained for determination of ET-1 concentration. Neutrophil extravasation was assessed by tissue myeloperoxidase (MPO) activity. RESULTS: arterial occlusion was associated with a gradual decrease of mucosal pO2 and local release of ET-1. After restoration of blood flow, mucosal pO2 returned to near baseline values, whereas ET-1 reached its maximum concentration during the reperfusion period. MPO activity was significantly increased. CONCLUSIONS: colonic ischaemia and reperfusion causes neutrophil extravasation and local ET-1.

Animals↗
PubMed2000

Surgery for aortoiliac aneurysms in kidney transplant recipients.

With the increase of long-term survivors following renal transplantation, aorto-iliac aneurysms requiring surgical management may be encountered more often. Our experience with temporary shunts for renal transplant protection during aorto-iliac aneurysm repair is presented along with a literature review of all cases on the subject. Three male patients with a median age of 56 (range 50-61) years were operated on for a dissecting aneurysm of the common iliac artery in one, respectively abdominal aortic aneurysm in the two remaining patients. All patients had impaired transplant function preoperatively with a median serum creatinine level of 167 (range 134-202) micromol/L and a median blood urea nitrogen concentration of 15 (range 9-23) pmol/L. The intra- and postoperative course was uneventful in all patients. Median postoperative serum creatinine level and blood urea nitrogen concentration were 135 (range 123-151) micromol/L and 10 (range 9-11) pmol/L, respectively. Aorto-iliac surgery in renal transplant recipients can be performed without transplant protection. However, in patients with a deteriorated transplant function or if a prolonged aortic cross-clamp time is anticipated, renal allograft protection measures may be beneficial to prevent possible ischemic damage.

Aortic Aneurysm, Abdominal↗
PubMed1999

Mural aortic thrombi: An important cause of peripheral embolization.

PURPOSE: Arterial thromboembolism in patients with an unknown source of embolization is still associated with significant morbidity and mortality. The advent of transesophageal echocardiography (TEE) and magnetic resonance imaging (MRI) and the more frequent use of computed tomography (CT) have led to the identification of mural aortic thrombi (MAT) as a source of distal embolization in a much higher proportion of patients than previously appreciated. The incidence, diagnosis, and treatment of patients with MAT is reported. METHODS: In a prospective study, from January 1996 to December 1998, 89 patients with acute embolic events underwent an extensive diagnostic workup, consisting of TEE, CT, or MRI, to detect the source of embolization. Patients in whom the heart (n = 51), occlusive aortoiliac disease (n = 16), or aortic aneurysms (n = 12) was identified as the source of embolization were excluded. RESULTS: Five female and three male patients, with a median age of 63 years (range, 35 to 76 years), with bilateral or repetitive embolic events resulting from MAT were identified, representing 9% of all patients with arterial thrombembolism. All patients had several risk factors for atherosclerosis, but only one young patient had a single risk factor that promoted thrombosis. Successful percutaneous catheter aspiration embolectomy was performed in six patients. The remaining two patients underwent surgical thromboembolectomy. A below-knee amputation had to be performed in two patients, thus representing a morbidity of the primary treatment of 25%. MAT of equal value were detected in the ascending (n = 1) and thoracic aorta (n = 3) by means of TEE, CT, or MRI. MAT in the abdominal aorta (n = 4) were identified by means of CT and MRI. Surgical removal of MAT was performed in seven patients by means of graft replacement of the ascending aorta (n = 1), open thrombectomy of the descending aorta (n = 2), and thrombendarterectomy of the abdominal aorta (n = 4), without intraoperative or postoperative complications. No recurrence of MAT occurred during a median follow-up period of 13 months (range, 4 to 24 months). CONCLUSION: MAT represent an important source of arterial thrombembolism. A diagnostic workup of the aorta, preferably by means of CT or MRI, should be performed in all patients in whom other sources of embolization have been ruled out. The ideal therapeutic approach to these patients still awaits prospective evaluation. However, based on our experience, MAT can be successfully treated with a definitive surgical procedure in selected patients, with low mortality and morbidity.

Adult↗
PubMed1999

Feline model of chronic obstructive pancreatitis: effects of acute pancreatic duct decompression on blood flow and interstitial pH.

BACKGROUND: The mechanism by which duct decompression (DD) relieves pain in patients with chronic pancreatitis (CP) is unknown. CP is associated with increased tissue pressure (IP), low pancreatic microvascular blood flow (PMBF), and interstitial pH (pH(I)). The aims of this study were to examine the effects of acute DD on PMBF, increased IP, and pH(I) in cats with CP. METHODS: The main pancreatic duct was partially obstructed. At 6 weeks PMBF (ml/min/100g H2 gas clearance), IP (mmHg needle electrode), and pH(I) (microelectrode) were measured before and after secretin stimulation. The duct was then opened, and the studies were repeated. RESULTS: PMBF normally increased with secretin stimulation (118 +/- 20 versus 271 +/- 52, P < 0.05). IP was unaltered, and pH(I) decreased as hydrogen ions produced during bicarbonate secretion were dissipated (7.41 +/- 0.01 versus 7.38 +/- 0.01, P < 0.05). In CP, basal PMBF was lower than normal (51 +/- 6 versus 118 +/- 20, P < 0.05) and decreased with stimulation (51 +/- 3.5 versus 31 +/- 3.5, P < 0.05). Basal pancreatic IP was increased (3.47 +/- 0.7 versus 0.05 +/- 0.3, P < 0.05) and increased further with secretory stimulation (3.47 +/- 0.7 versus 4.41 +/- 0.7, P < 0.05) (a compartment syndrome). The low basal pancreatic pH(I) (7.23 +/- 0.02) did not change with secretin stimulation, since bicarbonate secretion was minimal. DD decreased IP (3.66 +/- 0.5 versus 2.81 +/- 0.5, P < 0.05) and increased PMBF (50 +/- 6 versus 79 +/- 6, P < 0.05) and pH(I) (7.24 +/- 0.02 versus 7.34 +/- 0.02, P < 0.05). The normal increase in PMBF after stimulation was restored (79 +/- 6 versus 218 +/- 54, P < 0.05). pH(I) now increased with stimulation (7.34 +/- 0.002 versus 7.37 +/- 0.002, P < 0.05), perhaps due to the marked hyperaemic response. CONCLUSIONS: DD acutely restored basal and stimulated PMBF and IP towards normal. Basal pancreatic pH(I) also improved and reflects the underlying ischaemia.

Animals↗
PubMed1999

Effect of pancreaticojejunostomy on fibrosis, pancreatic blood flow, and interstitial pH in chronic pancreatitis: a feline model.

OBJECTIVE: To study the relation between fibrosis, pancreatic blood flow (PMBF), interstitial pH (pHi), and the effects of pancreaticojejunostomy (PJ) in chronic pancreatitis. BACKGROUND: Chronic pancreatitis is associated with low PMBF and pHi, suggesting the existence of underlying ischemia. METHODS: In cats, the main pancreatic duct was partially obstructed and the animals were studied 2, 4, 6, and 8 weeks later. PJ was performed after 2 and 4 weeks of ductal obstruction and studied 4 weeks later. PMBF and pH were measured before and after stimulation with secretin and cholecystokinin. pHi was measured with microelectrodes, PMBF by hydrogen gas clearance. Histologic analysis of the pancreas with Sirius red (collagen stain) and fast green FCF (noncollagen protein) stains allowed semiquantitative analysis of the ratio between collagen and total protein (C/TP). RESULTS: With the evolution of chronic pancreatitis, there is a progressive increase in the collagen content and C/TP ratio, a reduction in basal PMBF and pHi, and loss of the normal response to stimulation. Early PJ restores collagen content, C/TP ratio, and basal and stimulated PMBF and pHi to normal. PJ performed in established CP returns the C/TP ratio to normal, improves basal PMBF, and restores the normal hyperemic response to secretion. Basal pHi is improved and the "acid tide" associated with secretin returns, but there is still no response to cholecystokinin. CONCLUSIONS: Pancreaticojejunostomy restores the elevated collagen and C/TP ratio to normal and reverses the ischemia present in CP. The authors speculate that restoration of PMBF and its normal response to stimulation allows "regeneration" and restoration of secretory function.

Animals↗
PubMed1999

Selective use of temporary intravascular shunts in coincident vascular and orthopedic upper and lower limb trauma.

BACKGROUND: Combined vascular and skeletal injuries are associated with a high limb loss rate. One of the major factors resulting in amputation is frequently because the allowable warm ischemia time for skeletal muscle is exceeded before adequate revascularization. METHODS: Temporary vascular shunting has been used in selected patients with complete ischemia to minimize the ischemic time of the injured limb, allowing identification of vital structures, thorough debridement, and rigid internal fixation before definitive vascular repair. RESULTS: Five male and two female patients with a median age of 46 years (range, 27-76 years) admitted with combined orthopedic and vascular injuries of the upper limbs in four and the lower limbs in three patients underwent primary vascular shunting. The median ischemic time for all patients was 180 minutes (range, 120-210 minutes). Shunt insertion was accomplished in all cases within 30 minutes. Median dwell time for the shunt was 185 minutes (range, 90-390 minutes). No shunt-related complications or limb loss occurred. During follow-up ranging from 2 to 24 months, all vascular repairs remained patent. All fractures healed primarily, except for one patient in whom a necrosis of the humeral head occurred. Five patients had an excellent and two patients a good result. CONCLUSION: Initial temporary vascular shunting in selected patients with combined skeletal and vascular injury of the upper or lower limb may reduce the complications resulting from prolonged ischemia and permits an unhurried and reasonable sequence of treatment.

Adult↗
PubMed1999

Acute hemorrhage in chronic pancreatitis: diagnosis and treatment options including superselective microcoil embolization.

Acute hemorrhage in the course of chronic pancreatitis is the most serious and challenging complication, and its treatment has been the subject of controversy for years. We relate our experience in the management of this complication by superselective microcoil embolization. Five patients with acute hemorrhage resulting from chronic pancreatitis between 1994 and 1997 were included in this study. All patients were men with a median age of 44 years (range, 29-59 years). The bleeding occurred into a pseudocyst in all patients, with the splenic artery as feeding vessel. In all instances, the bleeding was successfully controlled by superselective microcoil embolization. Two patients underwent subsequent uneventful elective pseudocystojejunostomy. There was no mortality or morbidity, and no rebleeding occurred during a median follow-up of 22 months (range, 8-36 months). In appropriate patients, diagnostic angiography and superselective microcoil embolization may obviate the need for emergency surgery and should be considered as treatment alternative.

Acute Disease↗