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Biomedical subjects

D B Adams

Publications and source records attributed to D B Adams.

At least 19 recordsLinked to original sources
PubMed2003

An exploration of risk factors for bovine spongiform encephalopathy in ruminant production systems in the tropics.

The epidemic of bovine spongiform encephalopathy (BSE) in Europe in the late Twentieth Century required the interplay of two sets of factors, which now provide reference points for assessment of the BSE risk throughout the world. One set of factors consisted of the presence of infective agent in cattle or some other ruminant. The second set consisted of transmission and amplification of the disease, made possible through a particular feeding system that allowed persistent and habitual feeding of meat-and-bone meal (MBM) derived from cattle. The authors explore the ruminant production systems of three representative countries in South-East Asia against the background of factors required for the manifestation of BSE. The results can be extended to other countries in sub-tropical and tropical regions where similar, non-industrial ruminant production systems operate. In short, the lack of a nutritionally or economically rational niche for MBM as a source of dietary protein or nitrogen in many ruminant production systems removes the hazard of BSE.

Animal Feed↗
PubMed2001

Outcome of surgical treatment of chronic pancreatitis associated with sphincter of Oddi dysfunction.

The clinical management of patients with chronic pancreatitis (CP) associated with sphincter of Oddi dysfunction (SOD) presents many challenges. The aim of this study was to evaluate patient outcome after surgical management of CP associated with SOD intractable to medical management. The records of patients with CP and SOD who underwent surgical treatment between 1994 and 1998 were retrospectively reviewed and analyzed. Manometry of biliary and pancreatic ducts was performed. Basal pressures were considered abnormal if > or = 40 mm Hg for at least 30 seconds. Endoscopic retrograde cholangiopancreatography, endoscopic ultrasound, and clinical criteria were utilized in the diagnosis of CP. Quality-of-life issues were assessed. Twenty-nine patients were identified (21 women and eight men) with a mean age of 43.3 years (range 24-54). Mean basal biliary and pancreatic sphincter pressures were 155.1 and 90.4 mm Hg respectively. Chronic pancreatitis was graded as mild in nine patients, moderate in six, severe in two, and normal or equivocal in 12 patients according to the Cambridge classification. A Whipple procedure was performed in 17 (59%) patients, lateral pancreaticojejunostomy in nine (31%), and distal resections or a combination of procedures in three (10%). The morbidity and mortality rates were 21 and 0 per cent respectively. Mean follow-up was 30 months (range 3-48). Pain relief ranging from fair to excellent was seen in 83 per cent of patients with pain scores decreasing from an average of 9 (scale 1-10) before surgery to 3 postoperatively. Seventy per cent maintained their weight, 45 per cent continued to require pancreatic enzyme supplementation, and there were no changes in the status of diabetes. Rehospitalizations for recurrent pancreatitis or persistent pain were necessary in 24 per cent of patients. Surgical management of patients with CP and SOD who fail medical management is safe and effective in most patients. Operative morbidity and mortality are low, and the majority of patients have improvement in pain, although some require rehospitalization for recurrent pancreatitis and chronic pain.

Adult↗
PubMed2001

Does intraoperative electrohydraulic lithotripsy improve outcome in the surgical management of chronic pancreatitis?

Lateral pancreaticojejunostomy (LPJ) is the cornerstone of surgical management of pain associated with chronic pancreatitis (CP) and ductal dilation. The pathologic key to failure of LPJ is disease confined to the head of the pancreas. Intraoperative pancreatoscopy with electrohydraulic lithotripsy (EHL) is a novel technique that avoids resection and eradicates intraductal lithiasis in the head of the gland. This study was undertaken to compare outcome of LPJ alone and LPJ with intraoperative EHL in the surgical management of CP. The records of patients undergoing LPJ with intraoperative EHL between 1996 and 1998 (Group A) were reviewed and compared with our historical data of patients who underwent LPJ alone from 1977 through 1991 (Group B). Quality-of-life questionnaires were administered in person or by telephone. Fisher's exact and Mann-Whitney statistical tests were used where appropriate. Twenty patients (12 men, 8 women; mean age 51 years, range 29-68) in Group A underwent LPH with EHL versus 85 patients in Group B (65 men, 20 women; mean age 43.6 years, range 24-73) who had LPJ only. The etiology of CP was attributed to alcohol abuse in 85 per cent of patients in Group A and 96 per cent in Group B. Mean follow-up for Group A was 2.7 years (range 1-4 years) and 6.3 years (range 1-15 years) for Group B. Complications occurred in four patients (Group A) and five patients (Group B) perioperatively. There were no deaths in either group in the early postoperative period. Subsequent operations for complications of CP were significantly fewer in Group A than in Group B (P < 0.05). Rehospitilizations were required in 35 and 60 per cent of patients in Group A and B respectively (P < 0.05). Postoperative insulin and enzyme supplementation requirements were unchanged in Group A and continued or worsened in Group B. Ninety per cent of patients in Group A viewed their health status as good or fair compared with 55 per cent in Group B (P < 0.05). Postoperative narcotic use was present in both groups, although the number of pain pills used decreased considerably from 25 per week to fewer than five in Group A. Intraoperative EHL may represent an alternative to resection of the head of the pancreas or may be used as an adjunct to LPJ in the surgical management of chronic fibrocalcific pancreatitis.

Adult↗
PubMed2000

Failure of percutaneous catheter drainage of pancreatic pseudocyst.

Percutaneous catheter drainage (PCD) of symptomatic pancreatic pseudocysts under CT radiologic guidance is a valuable adjunct or alternative to operative pseudocyst management. PCD failure is characterized by the development of recurrent pseudocysts or external pancreatic fistulas. The purpose of this study is to define the cause and management of PCD failure patients. A retrospective review and analysis of patients with symptomatic pancreatic pseudocysts managed with PCD who required subsequent operative treatment because of PCD failure was undertaken. There were 23 study patients (18 men, 5 women) with a mean age of 44 years identified over a 13-year time period. Pancreatitis etiology was alcohol abuse in 10, gallstones in 7, pancreas divisum in 3, trauma in 2, and sphincter of Oddi dysfunction in 1. Endoscopic retrograde cholangiopancreatography findings were: 13 genu strictures, 4 main pancreatic duct dilations, 2 head strictures, 1 body stricture, 1 stricture in the tail, 1 intact duct, and 1 unknown. Operations used to manage PCD failures were: lateral pancreaticojejunostomy (LPJ) in 9 patients, Roux-en-Y pancreatic fistula jejunostomy in 7, distal pancreatectomy in 3, caudal pancreatectomy in 2, pancreatoduodenectomy in 1, cyst gastrotomy in 1, and caudal pancreatojejunostomy in 1. Follow-up has ranged from 1 to 13 years (mean, 5 years). Five patients who underwent pancreatic fistula jejunostomy developed recurrent pseudocysts or pancreatitis. There have been no recurrent pseudocysts or fistulas in patients managed with LPJ or pancreatic resection. Genu strictures were the cause of PCD failure in the majority of patients. LPJ is the treatment of choice for genu strictures but may not always be possible because of chronic inflammatory changes. Roux-en-Y pancreatic fistula jejunostomy is an acceptable alternative. Recurrent pseudocysts in the head and body are treated with LPJ with cyst incorporation. Pancreatic resection is appropriate for certain strictures of the head, body, and pancreatic tail. Failure of PCD is associated with an underlying ductal disorder that needs to be defined preoperatively with endoscopic retrograde cholangiopancreatography to select the appropriate operation.

Adult↗
PubMed1999

A pilot study evaluating the efficacy of a fully acetylated poly-N-acetyl glucosamine membrane formulation as a topical hemostatic agent.

BACKGROUND: Topical hemostatic agents are frequently needed for control of intraoperative bleeding. Currently available topical products each have potential drawbacks, making a more effective topical hemostatic agent desirable. This study was performed to evaluate the effectiveness of a particular formulation of a newly available polysaccharide polymer, poly-N-acetyl glucosamine (p-GlcNAc), as a topical hemostatic agent for use in the operating room. Swine splenic incision and splenic capsular stripping hemorrhage models were initially used, with a subsequent pilot human study then performed. METHODS: For the swine splenic incision model, anesthetized immature female Yorkshire white swine had a 3 x 8 mm incision created on the spleen. One of 3 agents (p-GlcNAc membrane, oxidized cellulose, or absorbable collagen) was sequentially applied to individual wounds and digitally compressed for 20 seconds. The wound was observed without pressure for 2 minutes. Up to 8 wounds per animal were created in 7 animals. For the swine splenic capsular stripping model a 2 x 2 cm area of capsular stripping on the surface of the spleen to a depth of 3 mm was created. Either p-GlcNAc membrane or oxidized cellulose was applied and digitally compressed for 60 seconds, followed by observation without pressure for 2 minutes. Six wounds per animal were created in 2 animals. If bleeding persisted in either model, a new cycle of compression was applied. These steps were repeated until hemostasis was achieved. No change in hemodynamics or coagulation factors was observed in either model. Subsequently, 10 consecutive patients undergoing elective small-bowel surgery were enrolled on pilot study. A 5 x 3 x 3 mm cruciate incision was created midway between the mesenteric and antimesenteric borders of the small bowel. Either p-GlcNAc membrane formulation or oxidized cellulose was applied (the sequence alternated per patient) with a 400-mg weight used for even, direct pressure. A second cruciate incision was then created on the contralateral side of the bowel to evaluate the second material. The number of applications required for hemostasis was assessed. Hemodynamics, small-bowel pathologic condition, and hematologic parameters were evaluated. RESULTS: The p-GlcNAc membrane required fewer cycles of compression in the swine splenic incision model to achieve hemostasis than either absorbable collagen or oxidized cellulose (1.25 vs 2.58 and 3.41, respectively; P < .01) and caused more effective immediate cessation of bleeding (79% for p-GlcNAc vs 17% for both absorbable collagen and oxidized cellulose). With the more traumatic splenic capsular stripping model, p-GlcNAc required fewer cycles of compression to achieve hemostasis than oxidized cellulose (average, 2.5 versus 6.8 respectively; P < .01) and was able to achieve hemostasis with greater efficacy (50%) in 2 applications than did oxidized cellulose (0%; P < .01). When used in the human pilot study, p-GlcNAc membranes required fewer cycles of compression than oxidized cellulose (2.5 vs 5.4, respectively; P < .002), was able to stop bleeding with greater efficacy in 1 cycle of compression (50% vs 0%, respectively; P < .01), and ultimately accomplished hemostasis in 80% of the cases as opposed to 20%. CONCLUSIONS: On the basis of its greater hemostatic efficacy as compared with collagen or oxidized cellulose-based products, p-GlcNAc holds promise as an effective topical hemostatic agent and deserves further evaluation.

Acetylation↗
PubMed1998

Endoscopic electrohydraulic lithotripsy in the management of pancreatobiliary lithiasis.

BACKGROUND: Clinical evaluation of intraoperative endoscopy with electrohydraulic lithotripsy (EHL) in the management of 13 patients with pancreatobiliary lithiasis was undertaken. METHODS: Ten patients with chronic pancreatitis with intraductal lithiasis in the head and three with biliary lithiasis (one choledochal, one cystic, one right intrahepatic) underwent intraoperative endoscopy with EHL. Shock waves were applied by visual contact with a 3-Fr gauge EHL probe until all stones were fragmented and irrigated free. All pancreatitis patients had failed ERCP attempts to stent their pancreatic ducts secondary to ductal lithiasis. Patients with pancreatic stones underwent lateral pancreatojejunostomy. Biliary stone patients underwent laparoscopic cholecystectomy with common duct exploration (two cases) and open cholecystectomy with choledochoduodenostomy (one case). RESULTS: Intraductal stone eradication was successful in all patients. Transampullary visualization of the duodenum was achieved in eight cases. Average EHL time was 65 min. There was no evidence of postoperative pancreatitis, cholangitis, or retained common duct stones. CONCLUSION: Intraoperative pancreatobiliary endoscopy with EHL is safe and effective in the eradication of pancreatic and bile duct stones. This novel technique represents a valuable adjunct in the management of chronic fibrocalcific pancreatitis with ductal lithiasis in the head region and in the open and laparoscopic management of intra- and extrahepatic bile duct stones.

Adult↗
PubMed1998

Outcome after laparoscopic cholecystectomy for chronic acalculous cholecystitis.

Patients with typical symptoms of biliary tract disease but no gallstones on ultrasonography may benefit from cholecystectomy for presumed chronic acalculous cholecystitis. We retrospectively analyzed the outcome of 50 patients with a preoperative diagnosis of chronic acalculous cholecystitis based upon history (chronic or recurrent, postprandial right upper quadrant abdominal pain), the absence of acid-peptic disease, and normal biliary sonography treated with laparoscopic cholecystectomy (LC) and transcholecystic cholangiography from 1991 to 1996. All patients had preoperative cholecystokinin-stimulated hepatobiliary scintigraphy (CCK-HBS). There were 42 women and 8 men with a mean age of 43 years. CCK-HBS was abnormal in 45 patients (< or = 35 per cent gallbladder ejection fraction or nonfilling of the gallbladder). There was no postoperative mortality and one morbidity (urinary retention). All patients had microscopic evidence of chronic cholecystitis. At mean follow-up of 30 months, (range, 7-62 months) 39 patients (78%) were free of abdominal pain. Thirty-five of 45 patients with abnormal CCK-HBS were pain free (positive predictive value, 0.78). Four of five patients with normal CCK-HBS were pain free (negative predictive value, 0.20). The positive and negative likelihood ratios for CCK-HBS were 0.99 and 1.13, respectively, confirming that this test was not useful for predicting benefit from LC. Seven patients with persistent right upper quadrant pain had abnormal postoperative sphincter of Oddi manometry; they improved after endoscopic sphincterotomy. Patients with symptoms typical of biliary colic with normal gallbladder sonography and absence of acid-peptic disease benefit from LC in the majority of cases. Those who remain symptomatic after LC may benefit from endoscopic retrograde cholangiopancreatography with sphincter of Oddi manometry and endoscopic sphincterotomy when manometry is abnormal.

Adult↗
PubMed1997

The effect of dexamethasone on immunological memory to tetanus toxoid in sheep.

One of two groups of sheep was immunosuppressed with the glucocorticoid, dexamethasone, at the time of the first but not of the second of two booster vaccinations with tetanus toxoid given at an interval of 28 days. Treatment with dexamethasone decisively reduced the anti-tetanus antibody response to the first booster vaccination and affected both IgM and IgG1 antibody. However, antibody titres increased after the second booster vaccination in the treated sheep and were similar in size to those in the untreated sheep which rose in stepwise fashion after each booster vaccination. The differences in response imply that processes involved in displaying an anamnestic response and recalling previously established memory are sensitive to glucocorticoids. Accordingly, they can be separated from the glucocorticoid-resistant processes that lead to the expansion of immunological memory following multiple exposures to an antigen.

Animals↗
PubMed1997

Differentiation of benign from malignant pancreatic masses by endoscopic ultrasound.

BACKGROUND: It is often difficult to determine whether a mass in the pancreas is benign or malignant. The goal was to evaluate whether endoscopic ultrasound (EUS) can reliably establish whether a mass is benign or malignant. METHODS: One hundred five patients with possible pancreatic tumors were referred for EUS. Those who were found to have a lesion suspicious for carcinoma and did not have a known malignancy also underwent EUS-guided FNA. RESULTS: A mass suspicious for cancer was identified in 73 patients, whereas inflammatory changes or a normal pancreas was noted in 32 patients. Four of the latter 32 patients were subsequently found to have cancer. EUS-guided FNA was performed on 47 of the 73 patients with a suspicious mass and was read as cancer in 27 patients, atypia in 10 patients, and benign in 10 patients. All 10 patients with atypia were subsequently confirmed to have cancer, and 6 of the 10 patients with a benign FNA were proved to have a tumor at surgery. EUS could differentiate the lesion as malignant with a sensitivity of 95%, specificity 88%, positive predictive value 95%, and negative predictive value 88%. CONCLUSIONS: Radial array EUS is helpful in supporting or refuting a diagnosis of cancer in a patient with a pancreatic mass. Although EUS-guided FNA can confirm the diagnosis, a negative FNA should not preclude exploration when clinically indicated.

Adenocarcinoma↗
PubMed1997

The effect of infection with the abomasal nematode, Haemonchus contortus, on the avoidance behaviour of sheep in a motivational-choice test.

The behaviour of immune and non-immune sheep infected with H. contortus and undergoing a variety of experimental treatments was investigated in a motivational-choice test, the arena test. This test evaluates motivational state in sheep by pitting the motivation of test animals to approach a small flock of sheep against the motivation to avoid a human decoy located directly in front of the small flock. Approach distance is decreased by infection in immune ewes but was unaffected by infection in non-immune weaner lambs in the present study. Experimental drug-treatments with the opiate-antagonist nalorphine, the antihistamine chlorpheniramine, and the immunosuppressive glucocorticoid dexamethasone, affected avoidance behaviour but did not shed light on possible mechanisms involved in the changes observed when immune sheep are infected with the parasite. These substances may affect motivational state directly and not through a pharmacological action on processes triggered by infection in immune sheep. Arena tests conducted in immune ewes at 4, 7 and 11 days after challenge infection showed a fluctuating locomotor behaviour, which may arise from either the dynamics of a standard secondary immune response or particular antigens released during larval development. The immune-mediated changes in behaviour in the arena test will have entailed information-processing or cognitive pathways, but it is not known whether they also involved the physiological manifestations of emotion.

Animals↗
PubMed1997

Public health hazards of meat from small ruminants: the perspective of Australia.

The production of meat from sheep and goats in Australia occurs almost entirely at pasture in zones known as the semi-arid pastoral zone, the wheat-sheep zone (where sheep and crops form an agricultural rotation system) and the high rainfall zone. Each zone has particular factors which affect the human health hazards associated with sheep and goat meat and the opportunities for prevention. The authors provide an overview of small ruminant production in Australia and a synopsis of the diseases encountered, including the factors which influence epidemiology. Animal health arrangements for underwriting food safety at the pre-harvest and post-harvest stages of production in Australia are also outlined. Specific public health hazards related to sheep and goat meat, together with measures for prevention, are considered under the headings of zoonoses, enteropathogens and chemical residues.

Animal Husbandry↗
PubMed1995

Management of biliary strictures due to laparoscopic cholecystectomy.

Injury to the extrahepatic bile ducts during laparoscopic cholecystectomy (LC) is a cause of serious long-term patient morbidity. In order to identify management strategies and outcome, we undertook a retrospective review and analysis of patients referred to the Department of Surgery and the Division of Gastroenterology for management of bile duct strictures due to injury at LC. Eighteen patients (15 women, 3 men) with a mean age of 41 years were identified over a 4-year period. Six patients had injuries identified at LC. Ten patients had previously undergone an attempt at operative repair (8 end-to-end anastomoses, 1 choledochoduodenostomy, 1 cystic duct jejunostomy). There were 5 Bismuth Grade I strictures, 6 Grade II, 2 Grade III and 5 Grade IV. Ten patients were managed nonoperatively with stents placed by radiologic or endoscopic techniques. Four patients were managed with operation alone (2 choledochojejunostomy, 1 hepaticojejunostomy, and 1 external T-tube drainage) and 4 patients with a combined endoscopic and operative approach (all 4 with hepaticojejunostomy after initial endoscopic retrograde cholangiopancreatography or percutaneous transhepatic cholangiography management). Bile duct strictures due to LC are frequently located in the proximal bile ducts (Bismuth II-IV) and are technically difficult to repair. In the majority of cases, injuries are unrecognized at LC. Both immediate and delayed repair attempts prior to referral were frequently unsuccessful. Many bile duct strictures can be managed successfully in the early postoperative period with endoscopic and radiologic stenting techniques. Strictures which cannot be managed nonoperatively are repaired with Roux-en-Y hepaticojejunostomy.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Cardiac ultrasound phantom using a porcine heart model.

A beating cardiac phantom has been developed using an excised porcine heart for use as a training tool in echocardiography. The heart is fixed with a formalin-based preservation method, housed in an optically transparent Lexan chamber, and undergoes hydraulic pumping to circulate a blood-mimicking fluid. The cardiac phantom has been used for a period of four months to produce images of excellent quality with ventricular wall motion typical of human subjects.

Animals↗
PubMed1994

Protein binding of brequinar in the plasma of healthy donors and cancer patients and analysis of the relationship between protein binding and pharmacokinetics in cancer patients.

The protein binding of weakly acidic and basic drugs has been shown to be altered in cancer patients. Brequinar is a weakly acidic, low-clearance, and highly protein-bound (> 98% bound) antitumor agent. The pharmacokinetic parameters of brequinar are subject to large interpatient variability. This large interpatient variability may be related to brequinar's plasma protein-binding capacity (assuming no change in the intrinsic clearance of the unbound drug). The objectives of this study, therefore, were (a) to characterize brequinar's protein binding in the plasma of healthy donors and cancer patients and (b) to examine the relationships between brequinar's plasma protein binding and its pharmacokinetics in patients. Brequinar protein binding was determined in human serum albumin (HSA) solution, drug-free donor plasma, and brequinar-free, predose plasma samples obtained from a phase I cancer trial. Pharmacokinetic results from this study were used to examine relationships between plasma protein binding and drug disposition. In HSA solution and healthy donor plasma, brequinar's protein binding as determined using spiked samples was concentration-dependent. The unbound brequinar fraction increased by a factor of 3 (from 0.3% to 0.9% free) in 4% HSA solution and by a factor of 4 (from 0.4% to 1.6% free) in donor plasma as the brequinar concentrations increased from 0.1 to 2.3 mM in the HSA solution and from 0.076 to 1.5 mM in the donor plasma. Analysis of brequinar binding characteristics using the binding ratio and Rosenthal binding plots showed that albumin was the primary protein for brequinar binding in human plasma. The addition of various concentrations of alpha 1-acid glycoprotein to 4% HSA solution did not affect the protein binding of brequinar to HSA. The protein binding determined in the plasma of cancer patients was not quantitatively different, except for variability, from that observed in the plasma of healthy donors. Examination of relationships between the unbound brequinar fraction and pharmacokinetics suggested that plasma protein binding was not a major determinant of brequinar disposition in cancer patients.

Antineoplastic Agents↗
PubMed1994

Laparoscopic cholecystectomy in pancreas transplant recipients.

Laparoscopic cholecystectomy is the treatment of choice for symptomatic cholelithiasis. Since its introduction in 1987, this procedure has been employed with increasing frequency as its safety has been documented in numerous studies. Absolute contraindications to laparoscopic cholecystectomy have become relative contraindications, and patients previously felt to be at excessive risk for laparoscopic cholecystectomy are viewed as patients who may benefit from laparoscopic cholecystectomy. The use of this procedure in patients with comorbid medical conditions has the potential to decrease patient morbidity. Patients who have previously undergone solid organ transplantation and require immunosuppressive therapy are a group of patients who may benefit from laparoscopic cholecystectomy. We report four patients who have previously undergone combined renal and pancreas transplantation who underwent successful laparoscopic cholecystectomy.

Adult↗
PubMed1994

Impact of laparoscopic cholecystectomy on the management of cholelithiasis in children with sickle cell disease.

Children with sickle cell disease, well known to have a high incidence of cholelithiasis, are frequently admitted to the hospital for episodes of abdominal pain. Before the advent of laparoscopy, few children with sickle cell and cholelithiasis underwent cholecystectomy unless absolutely necessary, because of the high morbidity of an open cholecystectomy (OC). We reviewed our records of all children with sickle cell disease and cholelithiasis treated from 1985 to 1992 to investigate the impact of laparoscopic cholecystectomy (LC). During that period, 32 children underwent cholecystectomy: 10 OC and 22 LC (all since December 1990). Before December 1990, all children had either classic biliary tract symptoms or abdominal pain of unknown etiology. However, of the 22 LC children, five had asymptomatic cholelithiasis. Only three of the 32 patients had choledocholithiasis, although 30 of 32 had elevated total bilirubins. Two LC children presented with choledocholithiasis and were initially treated with endoscopic sphincterotomy and stent placement. A standard intraoperative cholangiogram (IOC) through the cystic duct was performed in all OC cases. In 19 of 22 LC cases, an IOC through the gallbladder was performed before any dissection; unsuspected choledocholithiasis was not found, but the IOC did allow visualization of the course of the cystic duct, facilitating its subsequent dissection. Total operative length was comparable between the two groups, but the LC patients' postoperative length of stay was half that of the OC patients (2.1 v 4.6 days). Postoperative complications in the OC group included three children who had severe pain, atelectasis, fever, and hypoxemia (30%).

Adolescent↗