Primary aortoenteric fistula: pitfalls in the diagnosis of a rare condition.

Primary aortoenteric fistula is such a rare condition that even specialist vascular surgeons may not encounter one in their lifetime practice. Any hope of survival depends upon prompt diagnosis and surgical treatment. We present our experience of one such case, particularly the difficulties encountered in confirming the diagnosis, and go on to review the literature on the subject. Both our experience and that reported by previous authors would suggest that specialized investigations such as computed tomography, contrast angiography, radionuclide scintigraphy, and gastrointestinal endoscopy have only a limited contribution to make in confirming the diagnosis of primary aortoenteric fistula. The diagnosis should be considered in any patient with gastrointestinal blood loss and an abdominal aortic aneurysm. Specialized investigations should not be relied upon to confirm or refute the diagnosis. Any prospect of survival is dependant upon prompt diagnosis and surgical intervention. The latter is only achieved by a high index of clinical suspicion.

Screening for diabetes in lower limb amputees: a pilot study.

The Saint Vincent Declaration includes 5-year targets to improve the outcome of diabetic patients as a central tenet. Meeting these targets requires a comprehensive screening and monitoring programme to establish the current incidence of diabetic complications and show that the major goals of the declaration are being achieved. The Scottish Physiotherapy Amputee Research Group and the Scottish Vascular Audit Group jointly organized a three month prospective screening programme of 146 patients presenting for a lower limb amputation. The results suggest that a significant proportion of patients have undiagnosed diabetes. Further, only around half of the patients eligible for testing actually had a test done, highlighting the difficulties associated with establishing a national screening programme. This programme is now ongoing and particular importance is being given to improving the proportion of patients actually being tested.

Gastroenteritis causing critical limb ischaemia.

Six days after admission to hospital with Salmonella gastroenteritis, this patient presented with a critically ischaemic leg, having developed an iliac occlusion, and a subcutaneous Salmonella abscess in the anterior compartment of the leg. Critical limb ischaemia and abscess formation can be added to infective aortic aneurysm as vascular complications of Salmonella gastroenteritis.

Insonation and impedance analysis in graft surveillance.

Seventy consecutive patients with infrainguinal bypass grafts entered a 1-year graft surveillance programme involving colour duplex scanning, direct graft insonation and computer-assisted impedance analysis. Graft patients with a positive duplex scan, high frequencies on graft insonation or an impedance value above 0.50 subsequently underwent arteriography. Sixteen patients were excluded before the initial surveillance visit. The 54 remaining patients with grafts (30 vein, 24 synthetic) underwent a total of 137 surveillance visits, with 21 grafts confirmed to be 'at risk'. The sensitivity of an impedance value above 0.55 in identifying these grafts was 86 per cent, rising to 95 per cent when combined with graft insonation. Duplex scanning did not identify any abnormalities in 11 grafts that were either shown by arteriography to be 'at risk' or occluded before arteriography. Impedance measurement and graft insonation are simple screening techniques with a high sensitivity (when combined), which identify 'at risk' infrainguinal grafts. Positive graft insonation or an impedance value over 0.55 will identify all 'at risk' vein grafts while minimizing the number of unnecessary arteriograms.

Management of congenital arteriovenous malformations.

Over a 6-year period, 12 patients with 14 congenital arteriovenous malformations were considered for a staged approach to include afferent vessel ligation (AVL) and/or intra-arterial embolization (IAE) and surgical excision where possible. Patients were followed for a period ranging from 3 to 60 months. Two patients had localized lesions which were completely excised. Five patients were treated by IAE followed by excision with a successful outcome in four. One patient had a transmetatarsal amputation for failed IAE. Two patients had both IAE and AVL before excision of the lesion. In one patient AVL alone was followed by a recurrence. Two patients with multiple lesions were kept under observation. It would appear that IAE and excision of an arteriovenous malformation can achieve cure or excellent palliation in most patients.

Vascular injury after arterial catheterization.

Twenty-three cases of arterial injury after 8,208 arterial catheterizations for diagnostic or therapeutic indications at Glasgow Royal Infirmary are reviewed. Clinical presentation included haematoma formation, development of an acutely ischaemic limb or a false aneurysm. Patients with valvular heart disease are identified as a high risk group. Nine cases were managed by simple suture of the puncture site whereas thrombectomy and vein patch closure was required in 12 patients. The incidence of late complications requiring vascular reconstruction was 9%. The early recognition of complications after arterial catheterization and prompt referral to a specialized vascular unit is essential if morbidity is to be avoided.

Management of diabetes resistant to subcutaneous insulin with intravenous insulin via an implanted infusion pump.

Diabetes resistant to conventional subcutaneous insulin injection is a rare complication of insulin-dependent diabetes which poses a major management problem. We report three cases treated for a total of over seven patient years with fully implanted insulin infusion devices. Technical difficulties with the devices and their operation have been substantial but the patients are much improved and hospitalisation has been dramatically reduced. We suggest that implanted insulin pumps are a real treatment option for patients with this unusual syndrome.

Acute superior mesenteric ischaemia.

A review of case records and post-mortem reports from Glasgow Royal Infirmary over the past 12 years identified 102 patients with acute superior mesenteric ischaemia, 53 (52 per cent) of whom were first diagnosed at post mortem. Overall mortality was 92 per cent and mortality in the 49 patients diagnosed in life was 84 per cent. Fourteen patients (14 per cent) underwent exploratory laparotomy only with no survivors, 26 (25 per cent) had bowel resection alone with 7 surviving, and 9 (9 per cent) had a revascularization procedure, 5 requiring additional bowel resection, with only one surviving. Survivors were usually younger, had a shorter history and less extensive bowel infarction. Improvements in intensive care and nutritional support with the greater use of revascularization procedures in the past 6 years have barely influenced mortality. Delays in diagnosis and treatment contribute to the poor results. Earlier diagnosis might be aided by measuring serum inorganic phosphate and, coupled with the more widespread use of emergency angiography and revascularization procedures, holds out the best hope for future improvement.

Operation for late complications of aortic grafts.

In a period of seven years, 120 revision operations were performed for complications occurring in 1,284 aortic bifurcation grafts. The reasons cited for operation were: graft limb occlusion or stenosis in 82 patients, false aneurysm in 28 and symptomatic disease distal to the graft in ten. Preferred operations were replacement of the graft and distal anastomosis for occlusion or complete reconstruction of the anastomosis with fresh graft material for a false aneurysm. The operative mortality rate was 1.6 per cent and three patients (2.5 per cent) underwent amputation after multiple procedures. This group of 120 patients with complications was compared with a random sample of 300 patients with aortic bifurcation grafts with no complications. In the group with complications, there were significantly fewer patients who underwent sympathectomy or profundaplasty and significantly more with an iliac rather than a femoral artery graft insertion. Those patients who had graft complications develop also had a significantly higher hematocrit level at the first procedure.

Total colonic ischemia.

The involvement of the entire colon in an ischemic process is unusual because of the dual source of blood supply to the large bowel. Three cases of total ischemic colitis are presented. A precipitating cause to account for the distribution of ischemia was identified in each patient.

Genetic interaction between non-MHC T- and B-cell alloantigens in response to Rous sarcomas in chickens.

Chickens of Regional Poultry Research Laboratory (RPRL) inbred line 6(3) regress sarcomas induced by Bryan high-titer Rous sarcoma virus to a greater extent than chickens of line RPRL 100, although these lines are identical for the major histocompatibility B complex. They differ, however, at three independent autosomal loci: Ly-4 and Th-1 determine the surface alloantigens of partly overlapping subsets of T lymphocytes, and Bu-1 determines a surface alloantigen of B lymphocytes. The association of genotypes at these loci with quantitative variation in their ability to regress Rous sarcomas was tested in segregating F4 generation progeny derived from crosses of lines 100 and 6(3). The Ly-4 and Bu-1 genotypes showed association with Rous sarcoma regression, but the Th-1 genotype did not. Chickens of the Ly-4a/Ly-4a, Bu-1b/Bu-1b and Ly-4b/Ly-4b, Bu-1a/Bu-1a genotypes had a significantly higher regressor ability than the other two double homozygous genotypes. These results indicate that higher regression is associated with (1) interaction between the Ly-4 and Bu-1 loci, and (2) complementation between either the line 6 Ly-4a allele and the line 100 Bu-1b allele, or the line 100 Ly-4b allele and the line 6 Bu-1a allele.

Strong suppression by monocytes of T cell mitogenesis in chicken peripheral blood leukocytes.

Peripheral blood leukocytes (PBL) isolated from chicken blood by flotation on Ficoll-Hypaque (FH) have much lower proliferative responses to Con A and PHA than PBL isolated by slow-speed (SS) centrifuging at 60 X G. FH preparations contain all categories of blood cells except erythrocytes, whereas SS are almost devoid of nonlymphoid cells. FH responses approach SS levels after filtration through Sephadex G-10, which removes almost all monocytes detectable by neutral red and nonspecific esterase methods, while only partially depleting granulocytes and thrombocytes. Thus, the low responses of FH are probably associated with suppressor activity of monocytes in these preparations, numbering 6 to 8% of mononuclear cells. G-10 filtration decreases responses of SS preparations, indicating that the few (less than 0.1%) monocytes in SS function mainly as helper cells. In co-cultures, irradiated FH cells (FHX) but not SSX produce as much as 90% suppression of SS or FH responses. Suppression by FHX is totally inhibited by heat killing (56 degrees C for 45 min) or monocyte inactivation by preincubation with Trypan blue, and is removed by G-10 filtration, although not completely. Adherent cells isolated from unirradiated FH on Cytodex beads (ADC-CY) produce up to 99% suppression in co-culture with SS or nonadherent cells derived from FH. Soluble suppressor factors can be detected in conditioned media from supernatants of Con A-stimulated cocultures containing suppressor monocytes, but their suppressor activity is partially opposed by stimulatory factors, possibly interleukin 2, also present in supernatants. It is concluded that in FH preparations and therefore in blood, but not in SS, monocytes that have not been activated exert strong suppressor activity on mitogen-induced T cell proliferation. Occasional chickens of one inbred line, RPRL 72, had exceptionally high suppressor activity of monocytes, as shown by very low FH responses and very high suppressor effects of FHX well outside the normal range of variation found in this line or in line RPRL 63. This abnormal suppressor activity may have resulted from activation of suppressor monocytes as a response to subclinical infection.

Influence of genotypes at a non-MHC B lymphocyte alloantigen locus (Bu-1) on expression of Ia (B-L) antigen on chicken bursal lymphocytes.

Two inbred lines of chickens known to be identical at the MHC differ in their expression of Ia antigen on cells of the bursa. Line 6 bursas had 23% of intensely staining Ia+ cells while line 7 bursas had a much higher level, 85%. Studies of F4 progeny of line 6(3) X 100 crosses showed that genetic control of the high bursal proportion of Ia+ cells was determined by the Bu-1 alloantigen system. Line 100 is identical to line 7 for the lymphocyte alloantigens identified by the T and B cell reagents used in this study. Tests of F4 heterozygotes at the Bu-1 locus show a dominant effect of the Bu-1b gene in control of a high proportion of strongly staining Ia+ cells in the bursa.

Tests of association of lymphocyte alloantigen genotypes with resistance to viral oncogenesis in chickens. 2. Rous sarcoma and lymphoid leukosis in progeny derived from 6(3) X 15(1) and 100 X 6(3) crosses.

Chickens from inbred line RPRL 6(3) are resistant to virally-induced Marek's disease (MD) and lymphoid leukosis (LL) and are relatively strong regressors of virally induced Rous sarcomas. Line 6(3) chickens are homozygous for three independent loci determining surface alloantigens of lymphocytes, Th-1 and Ly-4 on thymus-derived (T) cells and Bu-1 on bursa-derived (B) cells. In contrast, RPRL Lines 100 and 15(1) are highly susceptible to MD and LL and are weaker regressors of Rous sarcomas than 6(3). RPRL Lines 100 and 15(1) are homozygous for different alleles at the Th-1 and Ly-4 loci than 6(3), whereas only Line 100 differs from 6(3) at Bu-1. To test the possible association of these three antigen loci with variations in resistance to virally-induced tumors, homozygous genotypes among later generations derived from 6(3) X 15(1) and 100 X 6(3) crosses were identified by means of immunofluorescence testing of peripheral blood lymphocytes. Test progeny were then bred from matings of homozygous parents. No association was found between Rous sarcoma regression and the Th-1 and Ly-4 T cell alloantigen loci in F6 (6(3) X 15(1)) chickens, but the Bu-1 locus influenced rate of regression in F3 (100 X 6(3)) chickens. The Ly-4 in F6 (6(3) X 15(1)) and Bu-1 in the F3 (100 X 6(3)) chickens did not influence the incidence of LL. However, Th-1 influenced LL in F3 (100 X 6(3)) chickens (P less than .05) and possibly influenced LL in F6 (6(3) X 15(1)) chickens (P less than .09).

Characteristics of chicken intraembryonic cells that express B-L (Ia-like) antigen under the influence of cultured bursal epithelium.

In-vitro-cultured bursal epithelium (BE) and BE-conditioned medium (BECM) induce B-L antigen on chicken intraembryonic cells. Cells prepared from 9-day-old intraembryonic mesoderm were fractionated in accordance with cell size by linear albumin gradient sedimentation at 1 g. Two cell types could be distinguished on which expression of the B-L antigen was altered after a 6-h incubation with the bursal epithelial component. One fraction contained small mononuclear cells with low sedimentation velocity (less than or equal to 3 mm/h) and low spontaneous proliferation activity. These cells responded strongly to BECM and showed a slight but not significant response to BE (index after incubation with BECM 3.8, with BE 1.7, as compared with RPMI medium control). The other fraction was composed of large mononuclear cells with sedimentation velocity greater than 9 mm/h and with high spontaneous proliferation. These cells showed a response of equal magnitude to both BE and BECM (index after incubation with BE 2.0, with BECM 2.3). These results suggest that the bursa of Fabricius has influence on two different cell types: a large, probably primitive undifferentiated cell, responding equally to bursal cellular contacts and BE culture supernatant, and a small mononuclear cell type, probably more mature, responding more clearly to the bursal humoral factor.