Search PubMed⌕ Search

Biomedical subjects

D B Adams

Publications and source records attributed to D B Adams.

At least 55 records · Page 3Linked to original sources
PubMed1991

Immunity to Haemonchus contortus and the cellular response to helminth antigens in the mammary gland of non-lactating sheep.

Cellular exudates induced by infusion with helminth antigens were examined in non-lactating mammary glands of ewes immune to infection with the abomasal nematode, Haemonchus contortus. Secondary immunological responsiveness was expressed in two ways. Firstly, antigens from adult H. contortus elicited larger eosinophil-rich cellular exudates in immune compared to non-immune ewes. In this situation, secondary responsiveness in the mammary gland must have been generated through abomasal infection with the parasite. Secondly, repeated infusion with the antigens from adult H. contortus increased the size of cellular exudates in both immune and non-immune ewes. Eosinophils predominated but numbers of macrophages and lymphocytes were also increased. In this second situation, secondary responsiveness must have been either supplemented in immune ewes or derived completely in non-immune ewes by contact with helminth antigens through the mammary gland. The helminth antigens which induce eosinophil exudates in the mammary gland may not be potently protective against H. contortus. Furthermore, eosinophil exudation may not be an in vivo correlate of immunity which is directly useful for discriminating protective antigens and applicable to vaccine development. Infusion with antigens from adult forms of either H. contortus or Trichostrongylus colubriformis elicited cellular exudates equally well in immune ewes primed by infusion with H. contortus adult antigens 7 days beforehand. In addition, antigens from infective larvae of H. contortus elicited cellular exudates more potently than antigens from adult worms. However, vaccination with irradiated larvae has shown that species-specific protective immunity for H. contortus is stronger than cross-protective immunity conferred by T. colubriformis.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Extent of bladder and ureteric involvement and urologic management in patients with enterovesical fistulas.

A retrospective review of hospital charts from 1978-1989 identified 21 patients with acquired enterovesical fistulas. Nine patients with fistulas secondary to benign inflammatory processes required extensive bladder resection; 2 of these had ureteric involvement. Of the 9 patients requiring extensive bladder resection, necrotic and severely inflamed bladder was excised and the bladder was closed in a multilayered fashion with absorbable sutures. An omental flap was used when possible. Postoperative bladder drainage was maintained for seven to fourteen days. Ureteral involvement was managed by stenting in 1 case and ureteroureterostomy in another. No postoperative bladder leaks or recurrent fistulas were reported. Extensive inflammatory involvement of the bladder wall may necessitate a large vesical resection. Excision of diseased bladder tissue, multilayered closure, and the use of omental interposition may help reduce postoperative complications and the risk of recurrence. Associated ureteral involvement may be present in these patients and requires urologic management.

Female↗
PubMed1991

Pancreatic pseudocysts. When to drain, when to wait.

Acute pain in the upper abdomen in a patient recovering from pancreatitis or abdominal trauma may herald a pancreatic pseudocyst. Although small cysts resolve spontaneously, those larger than 6 cm across usually require treatment to prevent such complications as rupture into adjacent structures and infection. The authors describe operative and nonoperative treatment methods and the success reported with each.

Drainage↗
PubMed1991

In utero sonographic appearance of the atrial septum primum and septum secundum.

We present our observation of the sonographic appearance of the septum primum and septum secundum. The septum primum, as the valve of the foramen ovale, has been previously described as a mobile, echogenic line or dot in the left atrium. We believe that these previous descriptions recognize only a small part of a more complex three-dimensional shape. We studied 14 ideal patients, none of whom were referred for suspected fetal cardiac disease. In 1 case the septum primum was seen as a flaplike structure and in 8 cases as a circular structure. In 5 cases it was seen as both flaplike and circular, depending on the scan plane selected. A three-dimensional description of the shape of the septum primum, based on the work of Crelin, is proposed, which explains these two appearances. A better understanding of this anatomical feature may prevent mistaking the septum primum for an abnormality and provide the basis for future advances in fetal echocardiography.

Echocardiography, Doppler↗
PubMed1991

Percutaneous catheter drainage of pancreatic pseudocysts.

Pancreatic pseudocysts represent a complication of severe pancreatic inflammatory disease. Although operative drainage is the cornerstone of therapy for pseudocysts, we have undertaken percutaneous catheter drainage in a selected group of 28 patients over a six-year period (1982-88). This represents 42 per cent of pseudocyst patients managed by the senior author and 1.7 per cent of admissions for pancreatitis at the Medical University Hospitals during that period of time. There were 26 men and two women with an age range of 26-66 years (mean = 42.1). Twenty-six patients had alcohol abuse as the cause of pancreatitis; two were due to surgical trauma. Nondilated pancreatic ducts were demonstrated in 25 patients. Six had pancreatic ascites associated with pseudocysts. Four had previous operative drainage (2 internal and 2 external drainage procedures). Five patients received octreotide acetate, a synthetic peptide which mimics the action of somatostatin, in an attempt to aid closure of external fistulas. The mean length of catheter drainage was 48 days (range 7-210 days). Eight (29%) patients developed procedure-related complications (1 pneumothorax, 1 sheared guidewire, six drain tract infections). There was no mortality. Successful resolution of pseudocysts was achieved in 26 patients (93%). Two patients subsequently had elective caudal pancreaticojejunostomy (CPJ), and one lateral pancreaticojejunostomy (LPJ) to drain obstructed pancreatic ducts. One patient has required repeat external drainage. Percutaneous external drainage is successful in pseudocyst eradication. When underlying pancreatic pathology remains uncorrected, elective surgical decompression of obstructed, dilated ducts may be necessary.

Adult↗
PubMed1991

Duodenal stricture: a complication of chronic fibrocalcific pancreatitis.

Over the past 10 years, one of us (M.C.A.) has treated 92 patients who required operation for symptoms associated with alcohol-induced chronic fibrocalcific pancreatitis. Four of these patients had duodenal obstruction. All four had had lateral pancreaticojejunostomy to relieve pancreatic ductal obstruction and associated chronic abdominal pain; three of the four also required biliary diversion for stenosis of the intrapancreatic portion of the common bile duct. Each duodenal stricture required reoperation and gastrojejunostomy to bypass the site of obstruction. A review of the English language literature revealed that duodenal obstruction in patients with chronic fibrocalcific pancreatitis is uncommon, only 58 previous cases having been reported. All of those patients had pancreatic ductal obstruction, and more than half had concomitant distal biliary stenosis. Two thirds of the duodenal obstructions were treated by gastroenterostomy, and one third were resected. Duodenal obstruction in patients with chronic pancreatitis and biliary stricture appears to reflect an advanced form of the disease. Combined lateral pancreaticojejunostomy and biliary diversion has emerged as the preferred surgical procedure for this problem. Careful preoperative assessment for evidence of duodenal stenosis also is needed in this group of patients, and gastroenterostomy is indicated in appropriate cases.

Adult↗
PubMed1990

Phase I and pharmacokinetic study of brequinar sodium (NSC 368390).

Brequinar sodium is a quinoline carboxylic acid derivative that has shown antitumor activity in a number of in vivo murine and human tumor xenograft models. Its mechanism of action is blockade of de novo pyrimidine biosynthesis by inhibition of dihydroorotic acid dehydrogenase. In vitro and in vivo studies demonstrate the superiority of prolonged drug exposure in achieving tumor growth inhibition. This phase I study evaluated the administration of brequinar sodium by short, daily i.v. infusion for 5 days repeated every 4 weeks. Fifty-four subjects were enrolled in the study and received drug in doses ranging from 36-300 mg/m2. The dose-limiting toxicities were mucositis and diffuse skin rash. Other toxicities included myelosuppression, nausea, vomiting, malaise, and burning at the infusion site. The maximum tolerated dose on the "daily times 5" schedule was 300 mg/m2. The recommended phase II dose is 250 mg/m2. Pharmacokinetic analysis of the day 1 drug clearance curves in 51 subjects showed slight nonlinearity in the relationship between dose and area under the clearance curve (AUC). The dose versus AUC relationship was well described using a Michaelis-Menten model of brequinar elimination kinetics with Vmax = 45 (micrograms/ml)/h and Km = 123 micrograms. Analysis of the day 5 drug clearance curves revealed a diminution in Vmax to 30 (micrograms/ml)/h. As a consequence of the reduction in Vmax brequinar plasma concentrations on day 5 were higher than predicted from day 1 drug kinetics. Pharmacodynamic analysis of the day 1 kinetic parameters and the toxicities occurring during the first cycle of drug therapy revealed significant correlations between mucositis and dose, AUC, and peak brequinar concentration; between leukopenia and AUC and peak drug concentration; and between thrombocytopenia and beta elimination rate.

Antineoplastic Agents↗
PubMed1990

Percutaneous catheter drainage of infected pancreatic and peripancreatic fluid collections.

Operative drainage is the cornerstone of therapy for pancreatic abscess. Recently it has been suggested that successful percutaneous catheter drainage of infected pancreatic and peripancreatic fluid collections may serve as definitive therapy. We undertook therapeutic, computed tomography-directed percutaneous drainage in a selected group of 29 patients with infected pancreatic and peripancreatic fluid collections. Twenty-three patients (79%) were successfully treated with percutaneous drainage. Of six patients (21%) representing failures of percutaneous drainage, four died and two recovered after operative drainage. The four patients who died had a mean APACHE (acute physiology and chronic health evaluation) II score of 23 and five of Ranson's prognostic signs. Ranson's signs and APACHE II scores were predictive of success and mortality. We conclude that in selected patients, infected pancreatic and peripancreatic fluid collections can be treated definitively with therapeutic percutaneous catheter drainage. Based on this experience, recommendations regarding patient selection are included.

Abscess↗
PubMed1990

Infection of immunosuppressed mice with the abomasal nematode parasite of ruminants, Haemonchus contortus.

Infective larvae of Haemonchus contortus established in mice either immunosuppressed with the corticosteroid, dexamethasone, or the cytotoxic drug, cyclophosphamide, or treated with the histamine H2 inhibitor, cimetidine. Infections persisted for as long as the immunosuppressive treatment (7 days) and growth of larvae was similar to that seen in sheep. Virtually no larvae survived in untreated mice. Accordingly, it would appear that adaptive immunity is an important barrier against primary infection by H. contortus in mice and is a determinant of host-range for this parasite. Antibody raised in either sheep or mice against soluble extracts of adult H. contortus precipitated with different but overlapping sets of worm antigens. This suggests that the unique antigens recognized by the mouse compared with the sheep are crucial for the rapid protective responses which prevent primary infection.

Abomasum↗
PubMed1990

In vitro analysis of jets by Doppler colour flow imaging: the importance of time to maximum jet area.

Regurgitant jets were simulated in vitro and analysed using Doppler colour flow imaging. The regurgitant volumes were estimated using total jet area (JA), variance area (VA), and the maximum area of variance x time to maximum area of variance (MAVT). Both flow rate and injected volume were significantly correlated to area of variance (r = 0.89 and r = 0.98, respectively) for a given orifice size. When MAVT was analysed, it correlated better to injected volume (r = 0.97) at a fixed flow rate, than varying flow rate (r = 0.69) at a fixed injected volume. The relationship between MAVT and injected volume was also examined with varying flow rate. There was a highly significant correlation between MAVT and injected volume under these circumstances (r = 0.99). A similar relationship between MAVT and injected volume was found when the orifice size was altered. Using multivariate regression analysis the injected volume was best defined by MAVT (R2 = 0.88). The addition of orifice size only improved the fit to the model marginally (R2 = 0.90). These data document the importance of analysing the time to maximum area of variance when applying Doppler colour flow imaging to regurgitant jets. MAVT is a better predictor of regurgitant volumes in vitro compared with jet sizes alone and may have potential use in man to quantify the severity of regurgitant valve lesions.

Aortic Valve Insufficiency↗
PubMed1990

Preoperative control of splenic artery inflow in patients with splenic venous occlusion.

Splenic vein occlusion due to chronic pancreatitis may result in "left-sided portal hypertension," which is associated with gastric variceal hemorrhage. Intraoperative hemorrhage is also a major problem in this patient group, and it has been suggested that preoperative splenic arterial occlusion offers a means to diminish intraoperative blood loss. In order to assess the benefit of preoperative control of arterial inflow on intraoperative blood loss, we reviewed retrospectively 16 cases of chronic pancreatitis and associated splenic vein occlusion in patients who had splenectomy. There was a significant difference in estimated intraoperative blood loss in the two patient groups (P less than .05). Preoperative inflow control was obtained with a wedge balloon catheter or autologous clot embolization with an estimated mean blood loss of 1771 mL in seven patients. Nine patients had splenectomy without inflow control, with a mean estimated intraoperative blood loss of 3332 mL. The mean difference was 1560 mL. Preoperative control of splenic artery inflow can diminish intraoperative blood loss during splenectomy in the presence of splenic vein occlusion associated with chronic pancreatitis.

Adult↗
PubMed1990

The intensity of resistance by mature Merino ewes against Haemonchus contortus and Trichostrongylus colubriformis in single-species and combined-species infection.

Three-year-old, non-lactating and non-pregnant Merino ewes, raised on pasture under a program of strategic treatment with anthelmintic and found to be extremely resistant to "trickle" infection with Haemonchus contortus, were given single-dose infections with either H. contortus or Trichostrongylus colubriformis or both species together. The purpose was to ascertain the intensity of protective immunity against the 2 parasites in sheep with immunity acquired from a presumably slight exposure to infection. To provide a criterion, some infected ewes were immunosuppressed with corticosteroid, dexamethasone. Untreated ewes were extremely resistant to challenge infection with either 15,000 or 150,000 H. contortus or 15,000 T. colubriformis. Surprisingly, when mixed infection was given, egg counts for H. contortus were significantly elevated compared with infection by that species alone. Antibody to antigens from infective larval and adult H. contortus was measured in serum by enzyme-linked-immunosorbent assay (ELISA) during the course of infection. Serum titres against larval antigens were significantly depressed when infections with either H. contortus or T. colubriformis were permitted by immunosuppression with dexamethasone, whereas those against adult antigen were depressed when infection with T. colubriformis was permitted.

Animals↗
PubMed1990

The effect of level of nutrition on the development of resistance to Haemonchus contortus in sheep.

Merino wether weaners, 5-months old at the start of the experiment and fed lucerne-based pellets at 600 g per head per day, developed resistance to Haemonchus contortus given as a continuous or "trickle" infection at the rate of 500 larvae 3 times per week over a period of 17 weeks. By contrast, the development of resistance was impaired in weaners fed pellets at 400 g per head per day. Low food intake and protein-energy deprivation, therefore, have a major effect in impairing the development and expression of host-protective immunity against haemonchosis. The point at which low food intake causes outbreaks of haemonchosis in sheep at pasture is critical in determining procedures for prevention and control of the disease.

Animal Feed↗
PubMed1990

Human immunodeficiency virus and the surgeon.

To assess the exposure risks for surgeons and nurses treating HIV infected patients at the Medical University Hospital and the Charleston Memorial Hospital, a retrospective review of HIV positive patients who underwent surgical procedures from 1985-1988 was undertaken. During that period, 150 patients tested positive for HIV of which 30 (20%) underwent 19 surgical procedures. The prevalence of HIV infected patients at our institution has been increasing over the last two years. 5.3% of the patients tested were positive for the virus. Evidence of drug abuse was not a predictive factor of HIV infection but homosexuality was present in 57% of our patients. The mean age of the surgical group was 34 years. Seventy-three percent of the patients underwent minor operations and 27% had major surgical procedures. Almost half of the operations were performed to treat an AIDS-related complication or as a diagnostic aid in the workup of the AIDS patient. Major operations performed were for treatment of a co-morbid condition not related to the HIV infection. Only two patients had operations for trauma. Operative mortality was 10% but no death was directly related to surgical intervention. In addition to universal precautions in the pre and postoperative period, operating room personnel must follow established protocols in the conduct of the operation to ensure the safety of all staff.

Adolescent↗
PubMed1990

Neuroendocrine tumor of the pancreas in a patient with pernicious anemia.

A total of 71 patients has been reported in the English literature to have developed carcinoid tumors in the fundus of the stomach in association with chronic atrophic gastritis secondary to pernicious anemia. The tumors appear to develop from argyrophilic cells in response to hypergastrinemia produced by hyperplastic G cells in the antrum of the stomach. We report a similar patient who, in addition, had a neuroendocrine tumor develop in the neck of the pancreas, which obstructed the pancreatic duct and resulted in severe chronic pancreatitis in the body and tail of the gland. There was an associated splenic vein thrombosis with left-sided portal hypertension. The pancreatic neoplasm was treated by excision, including the caudal 85 per cent of the pancreas and spleen. The gastric carcinoids appeared to diminish in size in response to a octreotide acetate (Sandostatin, Sandoz Pharmaceuticals; Hanover, NJ) administered to promote closure of a low-volume postoperative pancreatic fistula. The gastric lesions may require surgical treatment in the future. We were unable to find other examples of pancreatic neuroendocrine tumor occurring in association with pernicious anemia in a search of the English literature.

Adult↗