Biomedical subjects

J L Wellington

Publications and source records attributed to J L Wellington.

At least 19 recordsLinked to original sources

PubMed1996

Primary aortogastric fistula: a complication of ruptured aortic aneurysm.

An aortogastric fistula which resulted from rupture of an atherosclerotic aneurysm of the descending and supraceliac aortic segments is reported. The diagnosis was suspected preoperatively on the basis of CT and angiographic examinations. Vascular replacement was accomplished without difficulty, but a fatal outcome eventually occurred because of failure of local repair of the gastric defect. Relevant literature on primary aortoenteric fistulas has been reviewed, with particular emphasis on reports detailing management of the alimentary tract perforations. We now believe that resection should be strongly considered in situations where both resection and local repair of the enteric defect are options.

Aneurysm, Ruptured↗

PubMed1995

Pulsatile buttock mass: report of two cases and a review of the literature.

The presence of any pulsatile mass suggests an underlying aneurysm. When such masses occur in the buttock, the differential diagnosis includes aneurysms arising from branches of gluteal vessels or aneurysms developing in a persistent sciatic artery (PSA). The investigation and management of two patients with pulsatile masses are described. Review of the embryologic aspects of these masses and the important literature on the subject led to the conclusions that when a pulsatile buttock mass is encountered, an anomalous PSA should be suspected. A gluteal artery aneurysm can be treated by ligation or occlusion, but for a sciatic artery aneurysm surgical ablation is necessary and distal perfusion must be achieved postoperatively.

Adult↗

PubMed1993

Brachiocephalic fistula: a useful alternative for vascular access in chronic hemodialysis.

Construction of a Cimino-Brescia radiocephalic fistula is the current method of choice for vascular access in most patients on chronic hemodialysis. However, previous vascular access procedures, cephalic vein thrombosis or intrinsic arterial disease may render this procedure impracticable. The brachiocephalic fistula, which provides many advantages over the use of saphenous vein or prosthetic grafts for fistula access, is frequently overlooked as a surgical alternative in patients on chronic hemodialysis. Brachiocephalic fistula constructed directly between the brachial artery and cephalic vein at the level of the cubital fossa is associated with a 4.5-year patency rate of 80%. The incidence of complications is relatively low compared with that when interposition graft materials are used. However, two patients developed severe swelling of the upper extremity secondary to unrecognized preoperative subclavian vein thrombosis. The possibility of this complication should be suspected in any patient who has undergone previous percutaneous subclavian access.

Anastomosis, Surgical↗

PubMed1993

Acute abdominal emergencies in patients on long-term ambulatory peritoneal dialysis.

OBJECTIVE: To review intercurrent abdominal emergencies in patients receiving long-term peritoneal dialysis on an ambulatory basis. DESIGN: A chart review. SETTING: Tertiary care referral centre. PATIENTS: Seven patients receiving long-term peritoneal dialysis, who suffered an acute abdominal emergency during a 7-year study period. INTERVENTIONS: Laparotomy with appropriate management depending on the findings. Antibiotic therapy and dialysate culture. RESULTS: In all patients the acute abdominal process involved the colon: five patients had perforated diverticulitis and two had ischemic colitis. The death rate overall was 57%. Peritonitis in these patients was difficult to differentiate from the peritonitis that occurs commonly in patients on long-term peritoneal dialysis. As a result there was a delay in the initiation of therapy ranging from 2 to 27 days. CONCLUSIONS: Coincidental abdominal emergency should be considered when patients receiving long-term peritoneal dialysis on an ambulatory basis present with peritonitis that does not respond to established antibiotic protocols and when culture results show evidence of multiple enteric organisms.

Abdomen, Acute↗

PubMed1993

A comparison between expanded polytetrafluoroethylene and plasma tetrafluoroethylene grafts for hemodialysis access.

Animal studies have indicated that plasma tetrafluoroethylene (TFE) may be a better prosthetic material than expanded polytetrafluoroethylene (ePTFE) for arteriovenous access in patients who require hemodialysis because it combines the advantages of both Dacron and Teflon. A randomized clinical trial to compare the two materials was conducted between May 1987 and January 1989. Forty-four patients were enrolled, 22 in each group. The status of the grafts was monitored for at least 18 months. The patency rate for plasma TFE was 59% and for ePTFE was 64%. Kaplan-Meier analysis and Wilcoxon testing revealed no statistical differences between the two groups. Four grafts became infected, two in each group, and one aneurysm developed. Despite its theoretical advantages, plasma TFE was found to be similar to ePTFE as a graft material for hemodialysis.

Aged↗

PubMed1991

Lymphatic fistula after vascular reconstruction: a case-control study.

A retrospective case-control study was carried out to assess the importance of lymphatic fistulas that develop after vascular reconstruction and to determine the risk factors associated with them. The authors compared 35 patients who had lymphatic fistula after vascular reconstruction with 70 control patients, taken from the same database. They found a significant difference between the two groups only in age and indication for surgery: lymphatic fistulas were more likely to develop in older patients and in patients who underwent aortobifemoral bypass for limb salvage rather than for claudication (p less than 0.05).

Aged↗

PubMed1990

Cardiovascular response of a continuous variable rate alfentanil infusion for abdominal aortic surgery.

A prospective study was undertaken to determine the cardiovascular response of a continuous alfentanil infusion during abdominal aortic surgery (AAS). Each subject (n = 20) received a beta-blocking drug preoperatively, and was premedicated with oral lorazepam. Anaesthesia was induced with alfentanil 50 micrograms.kg-1 and thiopentone 3 mg.kg-1, and was maintained with a variable rate infusion of alfentanil and 66 per cent nitrous oxide in oxygen. During the infusion, boluses of alfentanil, 7.5 micrograms.kg-1, were administered to maintain heart rate and blood pressure within 20 per cent of awake baseline values. Haemodynamic stability during surgery was achieved with infusion rates varying between 0.5 and 2.5 micrograms.kg-1, which resulted in mean alfentanil serum concentrations ranging from 186 +/- 53 to 315 +/- 98 ng.ml-1. The mean cumulative alfentanil dose was 15.4 +/- 6.2 mg.patient-1 for surgery which lasted an average of 141 +/- 41 min. Throughout surgery, no patient required inhalational anaesthetic agents or vasoactive drugs. Fifteen of the 20 patients had perioperative Holter monitoring. No myocardial ischaemia was detected during the intraoperative period. However, there was a 33 per cent incidence of myocardial ischaemia on the first postoperative day. There were no myocardial infarcts and no deaths. We conclude that in beta-blocked patients undergoing aortic reconstructive surgery, a variable rate alfentanil infusion administered with 66 per cent nitrous oxide provides anaesthesia characterized by good haemodynamic control without the need for supplemental agents or vasoactive drugs.

Alfentanil↗

PubMed1990

Popliteal artery injury after tibial osteotomy: report of two cases.

Operative injury to the popliteal artery after meniscal surgery on the knee has been described previously, but its occurrence after tibial osteotomy has not been reported. The authors describe two cases of the latter condition, both involving the formation of a false aneurysm at the site of injury. The pathogenesis of this condition, its clinical sequelae and its subsequent repair are discussed.

Adolescent↗

PubMed1989

Hepatic artery aneurysm presenting as abdominal pain and hemoperitoneum.

Rupture of a hepatic artery aneurysm is one of the commonest causes of hemoperitoneum, second only to abdominal aortic rupture. The authors illustrate the difficulties of diagnosis and therapy in their description of the case of a 65-year-old man with a ruptured hepatic artery aneurysm. There are no pathognomonic features, and definitive diagnosis requires selective angiography of the hepatic artery. Early intervention by ligation or reconstruction may improve outcome but is associated with a high death rate. Selective embolization under fluoroscopic control may be preferable.

Abdomen↗

PubMed1989

Abdominal aortic aneurysm: consequences of a positive family history.

To assess the prevalence of coexisting abdominal aortic aneurysm (AAA) within certain families, a retrospective review was carried out of patients who had undergone AAA repair over a 5-year period. Contact was made with 305 families (52%) and a positive history of an affected, first-degree relative was obtained in 34 (11%). A known AAA was reported to affect approximately 20% of siblings at risk when the proband had an affected parent or sibling. Siblings of patients with an affected first-degree relative represent a high-risk group that may benefit from a screening program for earlier detection and elective management of AAA.

Aorta, Abdominal↗

PubMed1987

Retro-internal iliac artery ureter.

We report a case of retro-internal iliac artery ureter which was managed initially by division and ligation of this vessel. Use of an omental pedicle to minimize scarring and adhesion at the site of previous ureteric obstruction was unsuccessful and additional surgery was required for definitive decompression.

Adult↗

PubMed1985

Traumatic lymphocele following renal transplantation.

Post-transplantation lymphocele ordinarily is an early postoperative complication that infrequently causes symptoms, which usually result from impaired renal function secondary to cortical compression or ureteral obstruction. We recently encountered a patient in whom a lymphocele developed following trauma 7 years after cadaveric transplantation. Attempts to drain the lymphocele externally resulted in massive fluid loss, which caused hypotension, hypoproteinemia and profound electrolyte imbalance. Control of the massive fluid loss was achieved by marsupialization of the lymphocele into the peritoneal cavity.

Adult↗

PubMed1985

Extinction of response to urine odor as a consequence of vomeronasal organ removal in male guinea pigs.

It has been found that removal of the vomeronasal chemoreceptor organ (VNO) in male guinea pigs disrupted investigatory responses to conspecific odors but this disruption was time-dependent; immediately following surgery, behavior appeared almost normal, whereas several months following surgery, animals became very unresponsive to conspecific odor. It was hypothesized that in the absence of a functional VNO, the main olfactory system (MOS) was capable of maintaining response to conspecific odor but that this response extinguished following repeated exposures. However, postsurgical change in the central nervous system, unrelated to exposure to the bioassay, remained a possible explanation. In order to separate these hypotheses, the VNO was surgically removed in two groups of animals (A and B), and a third group (C) experienced sham surgery. Beginning 3 weeks following surgery, males in Groups A and C were given two standard urine-response tests/week for 24 weeks. Initiation of testing of Group B animals was delayed until Week 15 following surgery. Results indicated that (a) responses of Group A declined relative to those of Group C, (b) at the first postsurgical test, Group B was as responsive to urine as Group C and much more responsive than Group A and (c) a decline in responses for Group B occurred during tests after Week 15. The data therefore strongly supported the extinction hypothesis. The MOS is capable of eliciting a high level of investigatory behavior in response to female urine odors, but in the absence of the VNO, this response wanes, perhaps due to a loss of reinforcing properties associated with VNO stimulation.

Animals↗

PubMed1985

Gallstone ileus in the absence of the gallbladder: case report and review of the literature.

Although small-bowel obstruction due to gallstone ileus is uncommon, it assumes increasing importance with advancing age. The obstructing gallstone enters the bowel through an internal fistula between gallbladder and duodenum. The authors describe the case of a patient who had undergone cholecystectomy and in whom gallstone ileus occurred secondary to a stone that entered the bowel through a choledochoduodenal fistula. Treatment was traditional with removal of the obstructing stone, but the fistula was left undisturbed. The authors believe that further biliary tract symptoms are unlikely. The patient was well 8 weeks after operation and roentgenograms indicated that the internal biliary fistula was patent.

Aged↗

PubMed1984

Perineal scent gland of wild and domestic cavies: bacterial activity and urine as sources of biologically significant odors.

Several studies were conducted to evaluate the source of biologically relevant odorous substances in male wild cavy (Cavia aperea ) perineal gland secretions. In the first study, using a habituation procedure, male wild cavies distinguished between the urine of two individuals after exposure to the perineal secretions of one of the individuals. However, these animals did not distinguish between the perineal secretions of two individuals after exposure to the urine of one of the individuals. These results suggest that urine is a component of cavy perineal gland secretions as normally found in the perineal sac. Other studies were designed to evaluate the possible role of bacteria in producing biologically relevant odors from cavy perineal gland secretions. Microbiological analyses of secretion that had accumulated in the perineal sacs ("dirty") or been squeezed directly from the glands ("clean") of wild and domestic (C. porcellus) cavies indicated large numbers of bacteria inhabited these secretions. In behavioral studies using two-choice preference tests, male wild cavies spent more time investigating conspecific dirty perineal gland secretions than clean secretions. Clean secretions, however, which had been incubated for 48 hr at 37 degrees C were preferred by these cavies over clean secretions which had been frozen at -60 degrees C during the same time period. In a final experiment it was found that wild cavies preferred conspecific clean secretion that had been sterilized and incubated with bacteria over uninoculated sterilized secretion. Together, these results indicate that urine and bacteria are responsible for components of biologically significant odors of cavy perineal scent marks.

Animals↗

PubMed1984

Habituation to individual odors occurs following brief, widely-spaced presentations.

The possibility that male guinea pigs (Cavia porcellus) habituate to individual female conspecific urine odors following very brief, widely-spaced presentations was tested. On day 1 of test week 1, each male was exposed for 2 min to urine of one female, on day 3 to urine of a second female and on day 5 to urine of a third female. The number of seconds investigating the samples was recorded. This same procedure was repeated for 3 more weeks. On weeks 5 through 8, three novel females provided urine samples for testing which was conducted in an identical manner. On week 9, urine samples of the original 3 donors was tested. Results indicated that male guinea pigs habituated to urine odors presented for only 2 min 7 days apart and that dishabituation occurred following presentation of samples from novel donors. These data demonstrate an exquisite sensitivity to female urine odors, a long memory for individual differences in these odors, and a consistency over time in the composition of an individual's urine.

Animals↗

PubMed1983

Salvage of thrombosed polytetrafluoroethylene dialysis fistulas by interposition grafting.

Expanded polytetrafluoroethylene (PTFE) grafts are widely used for access in dialysis when a direct radiocephalic fistula is not possible. These grafts frequently fail as a result of thrombosis that follows the development of stenosis at the venous anastomosis. Since 1976, the author and his colleagues have had experience with eight patients who presented with acute occlusion of expanded PTFE fistulas. All were treated by immediate thrombectomy and interposition grafting to bypass the venous stenosis. Patency was satisfactory in most cases with follow-up of 1 to 17 months. The advantages of this operation over patch angioplasty at the site of the stenosed venous anastomosis are that it is technically easier and does not require visualization of the venous anastomosis or exact knowledge of the location of the stenosis.

Arteriovenous Shunt, Surgical↗

PubMed1982

Chemoinvestigatory and sexual behavior of male guinea pigs following vomeronasal organ removal.

The vomeronasal organs of male guinea pigs were removed (VNX; n = 10) or males experienced sham surgery (Sham; n = 10). Subsequently a battery of chemosensory tests of investigatory responsiveness to conspecific urine was conducted. Additionally, male subjects were paired with female conspecifics for short and long periods and social and sexual behaviors were monitored. VNX males exhibited a depression in urine investigation and this depression became more profound following repeated testing and/or the passage of time. By 6.3 months following surgery, investigatory responsiveness to urine was practically eliminated. Maintenance of responsiveness to urine odors may require reinforcing input through the accessory olfactory system. In contrast to these effects on responsiveness to odors, VNX and Sham males were indistinguishable in their social and sexual behavior. These data indicate that male guinea pigs without a VNO: (1) Exhibit a depression of investigation of urine odors which is time dependent and which may involve an extinction-like process; (2) continue to discriminate classes of urine (e.g., urine from male vs urine from female conspecifics); and (3) exhibit normal sexual behavior. The vomeronasal organ in the male domestic guinea pig is apparently critical for the maintenance of normal responsiveness to sex odors but, in its absence, other sensory systems are capable of maintaining normal sexual behavior under conditions of laboratory testing.

Animals↗