Access of urinary nonvolatiles to the mammalian vomeronasal organ.

Guinea pigs were allowed to investigate urine that contained rhodamine, a nonvolatile fluorescent dye. Guinea pigs given free access to dyed urine exhibited fluorescence in their vomeronasal and septal organs but not on their olfactory epithelium. Fluorescence was not seen when unadulterated urine was presented. Thus compounds of low volatility, which do not reach the olfactory epithelium, may stimulate the vomeronasal system and provide information that is normally not provided by gustation or olfaction.

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.

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.

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.

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.

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.

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.

Umbilical vein grafts for vascular access in patients on long-term dialysis.

Easy access to the vascular system is vital to any long-term dialysis program. The author's standard technique is an end-to-side radiocephalic arteriovenous fistula; grafts are reserved for situations in which a direct fistula is either impossible to construct or has failed. Although bovine and, more recently, expanded Teflon heterografts were successful initially, late failures from thrombosis or sepsis were not infrequent. Since February 1979, modified human umbilical vein has been used in patients needing a graft. It was used on 23 occasions in 21 patients. There were no early (within 30 days) failures. The overall patency rate from 2 to 26 months was 57%. Three infected grafts required removal, which was complicated by dense adhesion between the supporting Dacron mesh and adjacent tissues. No true aneurysms developed. After 1 year there was no obvious superiority of umbilical vein over expanded Teflon grafts. Longer follow-up is necessary to determine the ultimate role of umbilical vein grafts in patients on dialysis.

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.

Expanded polytetrafluoroethylene prosthetic grafts for blood access in patients on dialysis.

The difficulties in maintaining vascular access in patients on long-term hemodialysis are well recognized. The author's experience with bovine grafts in such cases had been that late failure from sepsis or thrombosis was common, as reported in the literature by others. In May 1976 the expanded polytetrafluoroethylene (PTFE) prosthesis became the substitute of choice as a vascular graft. In the last 18 months these grafts have been placed as subcutaneous arteriovenous fistulas in 22 patients. Three early failures occurred as a result of graft thrombosis but one graft was salvaged by thrombectomy using a Fogarty catheter. Two late failures occurred, one after 3 and another after 6 months. All other grafts are functioning satisfactorily. Expanded OTFE grafts provide satisfactory vascular access for maintenance hemodialysis in selected patients and their use may prove to be the procedure of choice for hemodialysis in small children.

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.

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.

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.

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.

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.

Thoracic surgery in the elderly.

With careful attention to details of preoperative, operative and postoperative care, intrathoracic procedures can be carried out safely in the elderly patient. The authors describe such procedures in 111 patients over 60 years of age who presented with a wide variety of primary diseases. Bronchogenic carcinoma, present in 48 patients, was the commonest. One-third of the total group had significant associated disease, usually in the form of coronary artery or chronic respiratory disease. The overall mortality rate was 6.3%.Before surgery, all patients were prophylactically digitalized regardless of their cardiac status. Blood volume estimations were determined in those with excessive weight loss. At operation, measurement of central venous pressure was found to be the best guide to blood replacement.Retention of bronchial secretions was the commonest postoperative complication. This problem can be minimized with intensive chest physiotherapy, adequate hydration, minimal doses of analgesic agents and, when indicated, early tracheostomy.

Bronchogenic cyst presenting as a supraclavicular mass.

Bronchogenic cyst is one of the more common congenital pulmonary anomalies. It is related to abnormal budding of the tracheobronchial tree during embryologic development. These lesions may present as a mass in the lung parenchyma in the mediastinum or within or below the diaphragm. An unusual case of bronchogenic cyst presenting as a mass in the supraclavicular fossa of a 24-year-old woman is reported. Treatment of bronchogenic cyst consists of excision of the mass. Recurrence is rare if excision is complete.