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Biomedical subjects

M Madan

Publications and source records attributed to M Madan.

At least 37 records · Page 2Linked to original sources

Ultrasound-guided unilateral neck exploration for sporadic primary hyperparathyroidism: is it worthwhile?

The role of preoperative localisation tests before initial neck exploration for primary hyperparathyroidism (PHP) remains controversial, as does the optimal surgical approach. We report our experience with preoperative ultrasound (US) and the operative management of sporadic PHP between 1990 and 1995. Preoperative US was carried out by an experienced radiologist. Three surgeons adopted a policy of 'selective' US-guided unilateral neck exploration (UNE); the fourth surgeon performed routine bilateral neck exploration (BNE). There were 72 patients: 26 men and 46 women, with a mean age of 57.4 +/- 12.5 years (range 21-80 years). All patients underwent initial neck exploration for 'sporadic' PHP, of whom 63 had preoperative US. This was positive in 52 patients; 27 of whom underwent a UNE, 23 had a BNE, and two patients had a UNE converted to a BNE. Patients with 'negative' US (n = 11), and those receiving no preoperative localisation test (n = 90) underwent a BNE. The sensitivity, specificity and accuracy of US were 80% (52/65), 100% (61/61), and 90% (113/126), respectively. Comparable success rates were achieved (BNE: 97% (33/34) vs UNE: 93% (27/29), P < 0.05), with very low morbidity. Failures with the scan-guided UNE were caused by missed contralateral adenomas. An experienced radiologist and a low incidence of multiglandular disease (MGD) are essential prerequisites for the scan-guided unilateral approach. An experienced surgeon, on the other hand, is the only prerequisite for the 'gold standard' bilateral approach.

Adenoma↗

Coronary stenting in unstable angina: early and late clinical outcomes.

OBJECTIVE: To examine the procedural and long term success of coronary stenting in patients presenting with unstable angina and the effect of warfarin on the clinical outcome of these high risk patients. DESIGN: A nonrandomized, retrospective analysis of patients presenting with unstable angina. SETTING: A tertiary care, Canadian university-affiliated teaching hospital. PATIENTS: Of 1250 patients who underwent percutaneous transluminal coronary angioplasty between January 1994 and June 1995, 365 underwent coronary stenting. The study population consisted of the 156 patients presenting with unstable angina who underwent coronary stenting. Patients with Canadian Cardiovascular Society class IV and postinfarction angina were included. INTERVENTIONS: Stent delivery by standard techniques to the target lesion was successful in all patients. At discharge, 88 patients were prescribed warfarin, ticlopidine and acetylsalicylic acid (ASA); the remaining 68 patients received only ticlopidine and ASA. Late clinical outcomes were assessed by telephone interview. RESULTS: The overall procedural success rate was 96%. One patient died in hospital (0.6%). Other events were abrupt closure (1.9%), myocardial infarction (1.9%) and urgent bypass surgery (1.9%). During follow-up, target vessel reintervention was needed in 19.6% of patients. Early and late clinical outcomes did not differ significantly between anticoagulated patients and those treated with antiplatelet agents alone, but anticoagulated patients had a significantly longer hospital stay. CONCLUSIONS: Coronary stenting in patients with unstable angina was associated with excellent procedural success and favourable late clinical outcomes. Warfarin added no apparent additional clinical benefit to antiplatelet agents in this high risk population.

Angina, Unstable↗

Haemorrhagic complications of pancreatitis: presentation, diagnosis and management.

Massive haemorrhage is an uncommon complication in pancreatitis. Most affected patients suffer from chronic disease with associated pseudocyst. We present five patients (four male) with a mean age of 41 years (range 34-48 years). All patients had alcohol-induced pancreatitis complicated either by haematemesis (3), intraperitoneal haemorrhage (1) or both haematemesis and intraperitoneal haemorrhage (1). Source of bleeding was pseudocyst wall (2), splenic artery pseudoaneurysm (2) and splenic artery rupture (1). Distal pancreatectomy and splenectomy was performed in two patients, intracystic ligation and drainage in two, and packing with subsequent external drainage in one. Rebleeding occurred in two patients and required subsequent distal pancreatectomy and splenectomy in one; the other patient died of splenic rupture. No rebleeding and no mortality occurred after resection. Primary pancreatic resection is recommended whenever possible. Other management options include embolisation and ligation.

Adult↗

A review of the management of abdominal aortic aneurysms in patients following cardiac transplantation.

OBJECTIVES: To describe the presentation, preoperative assessment and postoperative management of patients presenting with an infrarenal abdominal aortic aneurysm following a previous cardiac transplant. METHODS: The case histories of three patients have been examined and a literature review performed. CONCLUSIONS: The majority of patients developing aortic aneurysms had undergone cardiac transplantation for ischaemic cardiomyopathy and thus require detailed assessment of cardiac function preoperatively to exclude accelerated coronary artery disease in the graft. Full invasive cardiac monitoring during surgery is mandatory to maintain haemodynamic stability in patients with a dennervated heart and to avoid postoperative renal failure. The higher incidence of pulmonary and wound complications are discussed, together with protocols for maintaining adequate immunosuppression. Finally, data supporting a higher prevalence and more rapid expansion of aortic aneurysms in immunosuppressed patients is considered and evidence-based recommendations made regarding aneurysm screening in these patients.

Adult↗

Biology and applications of mycorrhizal fungi.

Mycorrhizae have been shown to increase growth and yield of plants. They have been identified with both nutrient mobilization and nutrient cycling. Arbuscular (or endo-) mycorrhizae play a significant role in agriculture and most natural ecosystems, whereas ectomycorrhizae have a great potential in forestry and wasteland regeneration. The use of mycorrhizal fungi would reduce dependence on chemical fertilizers besides minimizing environmental pollution. The present review addresses the progress that there has been in the area of the ecto- and endomycorrhizae. It also examines the potential of field applications of mycorrhizal biotechnology in agriculture and forestry.

Agriculture↗

Coronary stenting in acute myocardial infarction--patency demonstrated postmortem.

This report describes a patient with an acute anterior myocardial infarction treated by primary angioplasty and stenting of the infarct-related artery. The patient died 48 h later and at postmortem examination, patency of the stented artery was demonstrated, despite the adverse conditions which preceded death.

Angioplasty, Balloon, Coronary↗

Right atrial electrocardiography: a technique for the placement of central venous catheters for chemotherapy or intravenous nutrition.

Central venous catheters used for chemotherapy are usually sited so that the catheter tip lies in the superior vena cava. This study evaluated right atrial electrocardiography as a method of accurately placing the catheter tip in 34 patients over a period of 22 months. An electrocardiograph adaptor was connected to the catheter and the tip advanced into a central vein until a biphasic P wave was identified. In 31 of 34 patients the characteristic P wave changes were observed and the position of the catheter tip confirmed by screening to be in the superior vena cava. Right atrial electrocardiography is an accurate, reliable and rapid method of positioning the tip of a central venous catheter, and avoids or reduces exposure to radiation.

Catheterization, Central Venous↗

Fine bore silicone rubber and polyurethane catheters for the delivery of complete intravenous nutrition via a peripheral vein.

The aim of the study was to evaluate two fine bore catheters for the delivery of complete intravenous nutrition (IVN), of osmolality 1250 mosm/kg, via a peripheral vein. 50 patients were randomised to receive either a 23G silicone rubber catheter or 22G polyurethane catheter. The median duration of feeding was 9 days for silicone rubber catheters and 10 days for polyurethane catheters. Silicone rubber catheters developed complications significantly more frequently (44%) than polyurethane catheters (22%, p < 0.05). There was no significant difference in the median life span of the catheters removed because of complications, nor in the daily risk of thrombophlebitis. 92% of patients who were fed through a polyurethane catheter required only a single catheter for the duration of IVN. The peripheral venous route should be the first choice when the administration of IVN is considered for a period of less than 2 weeks.

Journal Article↗

Influence of catheter type on occurrence of thrombophlebitis during peripheral intravenous nutrition.

To reduce the likelihood of thrombophlebitis during intravenous feeding through a peripheral vein, the osmolality of the solution is usually reduced by disproportionately raising the lipid content and lowering the carbohydrate, electrolyte, and aminoacid concentrations. The possibility that delivery system rather than feed is the main influence on the development of thrombophlebitis was examined in a randomised comparison of a fine-bore silicone catheter against a short 'Teflon' cannula. The nutrient solution given through a peripheral vein was a standard feed used for infusion into a central vein (osmolality 1250 mOsmol/kg, 13 g nitrogen, 200 g glucose [800 kcal], and lipid emulsion [1000 kcal]). 27 patients received the infusion through a fine-bore silicone rubber catheter (diameter 23 G, length 15 cm) and 23 through a teflon catheter (diameter 20 G, length 3.2 cm). The median duration of feeding was 5 days in each of the two groups. Thrombophlebitis developed in all patients in the teflon group but in only 2 (7%) of the silicone group. The first silicone catheter for a patient lasted a median of 128.5 h, compared with 40 h for the first teflon cannula (p less than 0.001). The results show that when a nutrient solution of osmolality 1250 mOsmol/kg is delivered through a peripheral vein with an ultrafine-bore silicone catheter, the risk of thrombophlebitis is low. For many patients intravenous feeding may thus be given through a peripheral instead of a central vein without compromising the nutritional adequacy of the feed.

Adolescent↗

Long-term weight control study. I (weeks 0 to 34). The enhancement of behavior modification, caloric restriction, and exercise by fenfluramine plus phentermine versus placebo.

To investigate the value of anorexiant medications as an adjunct to other forms of weight control therapy, we studied 121 people in a 34-week, double-blind clinical trial of 60 mg extended-release fenfluramine plus 15 mg phentermine resin versus placebo added to behavior modification, caloric restriction, and exercise. Participants weighed 130% to 180% (154% +/- 1.2%, mean +/- SEM) of ideal body weight (1983 Metropolitan Life tables) and were in good health. By week 34, participants receiving active medication lost an average of 14.2 +/- 0.9 kg, or 15.9% +/- 0.9% of initial weight (n = 58), versus a loss of 4.6 +/- 0.8 kg or 4.9% +/- 0.9% of initial weight by subjects taking placebo (n = 54; p less than 0.001). On visual analog scales, participants rated fenfluramine plus phentermine as more helpful than placebo (50.3 +/- 0.5 versus 20.3 +/- 0.3) and not bothersome (fenfluramine plus phentermine, 17.4 +/- 0.3 versus 13.5 +/- 0.2). Blood pressure decreased and pulse remained unchanged in both groups. Dry mouth was the most common adverse effect in subjects receiving fenfluramine plus phentermine; all adverse effects decreased after 4 weeks. Only nine participants left the study in the first 34 weeks. Two subjects from each group left the study as a result of adverse effects. Overall, fenfluramine plus phentermine used in conjunction with behavior modification, caloric restriction, and exercise aided weight loss and continued to be efficacious for 34 weeks.

Adult↗

Long-term weight control study. II (weeks 34 to 104). An open-label study of continuous fenfluramine plus phentermine versus targeted intermittent medication as adjuncts to behavior modification, caloric restriction, and exercise.

Between weeks 34 and 104, we explored different schema for administering fenfluramine plus phentermine in open-label fashion. At week 34, the original placebo group participants began taking fenfluramine plus phentermine (placebo-to-active group). Those receiving fenfluramine plus phentermine between weeks 6 and 34 either continued to receive medication or began targeted intermittent therapy. Participants who did not lose 10% of initial weight received an augmented dose (60 mg fenfluramine plus 30 mg phentermine. The placebo-to-active group lost an additional 9.1 +/- 0.8 kg (mean +/- SEM) in the period from week 34 to week 60. At week 60, they were assigned to either continue medication, intermittent therapy, or augmented therapy. More than 68% (83) of the original participants completed up to study week 104. At that point, overall weight loss was 10.8 +/- 0.7 kg (11.6 +/- 0.8% of initial weight); participants who continued to receive fenfluramine plus phentermine lost 11.6 +/- 0.8 kg, participants receiving intermittent therapy lost 11.6 +/- 1.3 kg, and participants receiving augmented therapy lost 6.5 +/- 1.5 kg. Although 41% of the participants complained of dry mouth, neither serious adverse effects nor evidence of medication abuse appeared. There were 29 dropouts in the period from weeks 34 to 104. Sixteen of those were related to medication (adverse effects, lack of efficacy, and fear of medication). Overall, fenfluramine plus phentermine used in conjunction with behavior modification, caloric restriction, and exercise continued to be efficacious for up to 2 years.

Adult↗

Evidence for the indirect utilization of glucose for the synthesis of hepatic glycogen in man.

1. This study was designed to test the hypothesis that three-carbon intermediates can be used in the 'indirect' pathway of glycogen synthesis in human liver (i.e. a route additional to the use of glucose by the 'direct' pathway). 2. After an overnight fast, 13 patients were given an infusion of 20% (w/v) glucose before elective abdominal operation. All received a 2.5 g bolus of 2220 kBq of selectively 3H- and 14C-labelled glucose before removal of a 1 g biopsy of liver. 3H and 14C were determined in purified glycogen as well as in glucose and lactate from samples of peripheral blood. 3. The ratio and specific activities of 3H and 14C in glycogen were found to be significantly lower than those in administered glucose. By calculation, 7-74% of glycogen repletion occurred by indirect pathways and not all of this was from the glucose supplied. 4. This study suggests that the operation of a direct pathway in man is not exclusive and that significant repletion of hepatic glycogen occurs by an indirect route.

Adult↗

A randomised study of the effects of osmolality and heparin with hydrocortisone on thrombophlebitis in peripheral intravenous nutrition.

Intravenous nutrition administered via the central route incurs both the risks of catheter insertion and catheter related sepsis. Peripheral intravenous nutrition avoids these risks but is associated with a high risk of thrombophlebitis. We undertook a study to look at the incidence of thrombophlebitis caused by the infusion of a) a 'ready to use' mixture (Vitrimix KV) with an osmolality of 1130 mOsmol/kg, b) Vitrimix KV plus heparin and hydrocortisone, and c) a feed, with an osmolality of 700 mOsmol/kg, with heparin and hydrocortisone, to investigate the effects of the addition of heparin and hydrocortisone and the effect of osmolality on the incidence of thrombophlebitis. The addition of heparin (500 u/l) and hydrocortisone (5 mg/l) to Feed A significantly reduced the daily risk of thrombophlebitis from 0.43 to 0.11 episodes per patient, p < 0.01. A reduction in the osmolality resulted in a further fall in the incidence of thrombophlebitis to 0.04 episodes per patient with a significant increase in the median life span of the cannula from 26 h to 86 h, p < 0.02. Our data show that a low incidence of thrombophlebitis can be achieved by the use of a low osmolality feed with heparin and hydrocortisone. It is recommended that peripheral intravenous nutrition be used in patients who require nutritional support for less than 10 days.

Journal Article↗

Does milk have a cataractogenic effect? Weighing of clinical evidence.

We undertook a prospective study to test Simoons' hypothesis that in certain susceptible races milk exerts a cataractogenic effect. Overall milk intake in low lactase deficiency areas did not correlate with cataract occurrence. Subgrouping of cataract patients revealed that greater milk intake did show positive correlation with cortical cataracts. Cortical cataracts were also markedly more common in females. Analysis of data from three different regions showed greater milk intake in cortical cataract patients only. Our data indicate the importance of specifying cataract type in cataract studies and highlight the problem this approach brings forth. We noted no different trends in subjects from northwest and southeast India, although the number of subjects from the southeast was considerably less. Patients with early cortical cataracts may be advised to restrict milk intake.

Adult↗