Femoro-femoral or ilio-femoral bypass for unilateral inflow reconstruction?

Femoro-femoral and ilio-femoral bypass are two popular options for unilateral inflow reconstruction. In order to evaluate these alternative approaches, the records of 70 consecutive patients who underwent either femoro-femoral (n = 50) or ilio-femoral (n = 22) grafts were retrospectively reviewed. There were 46 men and 24 women, ranging in age from 27 to 84 years (mean: 66 years). Operative mortality was 10% for all femoro-femoral procedures, including 50% for emergent, 14% for synchronous, and 0% for solitary procedures; mortality was 9% for all ilio-femoral grafts including 20% for synchronous and 6% for solitary procedures. Among the elective solitary procedures, there was no significant difference with respect to operative time, blood loss, fluid requirement, time until resuming an oral diet, or duration of postoperative course for the two procedures. Five-year patency was 93% for all ilio-femoral and 57% for all femoro-femoral grafts. Although femoro-femoral bypass has been the more popular option for unilateral inflow reconstruction in this and other institutions, these findings justify the more widespread use of ilio-femoral bypass.

Experimental treatment of thrombotic vascular occlusion

The role of laser energy in the treatment of thrombotic vascular occlusion was evaluated in two sets of experiments. First, 10 polytetrafluoroethylene grafts were used to replace segments of the superficial femoral arteries in dogs and were thrombosed by distal ligation. Occlusion was maintained for one hour, or for 7, 14, 21, and 28 days in each of two grafts. Patency was restored in all 10 grafts without perforation or anastomotic disruption using a 2 mm hot tip probe powered by an Argon laser. However, increased organization of thrombus related to the duration of occlusion lead to decreased laser channel diameters, and 75% of the 28 day thrombus remained in the graft after recanalization. The second experiments tested the added benefit of thrombolytic infusion following laser recanalization. Bilateral external iliac artery thrombosis was induced in dogs by operative vessel isolation, de-endothelialization, and thrombin injection. At 7 days the efficacy of laser-assisted thrombolysis (LAT) versus enzymatic thrombolysis (ET) alone was compared. Eight vessels underwent ET by urokinase (4000 I.U./min.); 14 vessels were laser recanalized prior to thrombolytic infusion. LAT was performed from a carotid artery approach in 8 vessels (antegrade) and from a femoral artery in 6 vessels (retrograde). In contrast to studies using the hot tip alone, both ET and LAT accomplished complete thrombus removal. However, LAT lead to significant iliac arterial flow in 9 +/- 8 min. (antegrade) and 25 +/- 8 min. (retrograde) while ET required 109 +/- 47 min (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Angiographic localization of spinal cord blood supply and its relationship to postoperative paraplegia

Forty-seven patients underwent selective catheterization of middle and lower thoracic intercostal and upper lumbar arteries to define the origin of the artery of Adamkiewicz. One patient had significant atheroembolism, and a second had transient lower extremity paresthesias. No other complications occurred. The origin was found in 26 (55%), and 21 patients underwent thoracoabdominal aneurysm repair with this knowledge. When the critical lumbar or intercostal artery could be included as part of a long proximal or distal anastomosis, all 12 patients could be included as part of a long proximal or distal anastomosis, all 12 patients survived, and one was paralyzed. However, if the aneurysm repair mandated a midgraft anastomosis to intercostal arteries critical to spinal cord perfusion, seven of nine patients either died or were paralyzed (p less than 0.05). In the group of 19 patients operated on in whom spinal cord blood supply was not identified three patients had a technically unsuccessful operation; two died, and one was paralyzed. Twelve of 16 patients who had an adequate, but unsuccessful attempt at localization were treated by intercostal "neglect" and survived. Late paresis developed in two patients, but they are walking now. One of the patients who died had multiple systems failure and awakened paraplegic. She had a patent, enlarged, thoracic radicular artery at T-5 which probably supplied to spinal cord and which was missed angiographically. Paralysis was associated with aneurysm extent (group 2 and III B, dissections vs group 1 & 3, p less than 0.05). Selective intercostal angiography requires further refinement, but it is safe and offers the promise of understanding the mechanisms and risks of spinal cord complications after repair of extensive thoracoabdominal aneurysms.

Carotid-subclavian bypass--a decade of experience

From August 1979 to August 1989, carotid-subclavian bypass or transposition procedures were performed on 18 women and 13 men ranging in age from 19 to 75 (mean, 58.2) years. Indications for surgery included symptoms of vertebrobasilar insufficiency in 16 (52%), upper extremity ischemia in six (19%), both vertebrobasilar insufficiency and extremity ischemia in four (13%), and stroke and/or hemispheric transient ischemic attacks in four (13%) patients. One patient (3%) had angina pectoris caused by "coronary-subclavian steal." Formal bypass grafts were performed in 28 (90%) cases by means of polyterafluoroethylene (24), Dacron (2), or saphenous vein (2), and carotid-subclavian transposition was performed in three (10%) cases. Synchronous procedures included carotid endarterectomy (4), carotid-carotid bypass (1), and axillobrachial bypass (1). There was no operative mortality. Thirty-day primary patency was 97%. Follow-up has ranged from 1 to 121 (mean, 42) months. Three grafts (polytetrafluoroethylene) have occluded during follow-up yielding long-term primary patency of 92% at 5 years and 83% at 8 years. Relief of symptoms was initially achieved in 30 (97%) patients. Recurrent symptoms have developed in six (20%) patients from 2 to 55 (mean, 26) months after surgery, including two with occluded and four with patent grafts. Symptom-free survival is 89% at 1 year, 84% at 2 years, and 71% at 7 years of follow-up. Six patients have died during follow-up yielding overall survival of 88% at 5 years, and 48% at 10 years.(ABSTRACT TRUNCATED AT 250 WORDS)

Toxicity studies of butylated hydroxyanisole and butylated hydroxytoluene. I. Genetic and cellular effects

The cellular effects of the antioxidants butylated hydroxyanisole and butylated hydroxytoluene were studied in a battery of in vitro tests. No evidence of genotoxicity was obtained for either compound in the hepatocyte primary culture/DNA repair test, the Salmonella/microsome mutagenesis test, the adult rat liver epithelial cell/hypoxanthine guanine phosphoribosyl transferase test, or for butylated hydroxyanisole in the Chinese hamster ovary cell/sister chromatid exchange test. Both compounds inhibited intercellular molecular exchange between cultured liver cells, an effect that has been observed for many agents with neoplasm-promoting activity.

Toxicological studies on a benzofurane derivative. II. Demonstration of peroxisome proliferation in rat liver

The uricosuric drug benzbromarone (3,5-dibromo-4-hydroxyphenyl)-1-(2-ethyl-3-benzofuranyl)methanone, a benzofurane derivative, was studied for its effects on parameters related to hepatic peroxisome proliferation. Groups of male F-344 rats were fed either basal diet, the peroxisome proliferator clofibrate at 5000 ppm as a comparison compound, or benzbromarone at two doses, 1000 and 2000 ppm. Benzbromarone and clofibrate produced hepatomegaly and increases in the activities of catalase, acyl CoA oxidase, malate dehydrogenase, and glycerol-3-phosphate dehydrogenase. Benzbromarone and clofibrate also both induced similar histologic and ultrastructural changes in hepatocytes, including induction of peroxisomes. Therefore, benzbromarone acted as a peroxisome-proliferating agent in rats under these conditions. Benzbromarone differs from other peroxisome proliferators in its chemical structure, uricosuric action, and the morphology of liver peroxisomes that were induced by exposure.

Toxicity studies of butylated hydroxyanisole and butylated hydroxytoluene. II. Chronic feeding studies

The antioxidants butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) were fed in the diet to male F344 rats in two chronic feeding studies. In one study, feeding BHT for 76 wk at concentrations ranging from 100 to 6000 ppm produced no increase in neoplasms at any site. In a second study, feeding 12,000 ppm BHT for 110 wk had no neoplastic effect at any site, whereas feeding BHA at 12,000 ppm resulted in a small increase in squamous cell papillomas of the non-glandular squamous portion of the stomach.

The relationship between erythrocyte transketolase activity and the 'TPP effect' in Wernicke's encephalopathy and other thiamine deficiency states

Patients (n = 104) were judged to be thiamine deficient by the criteria of erythrocyte transketolase activity (ETK) less than 0.6 U/g of hemoglobin, or greater than 17% increase in this activity on addition of thiamine pyrophosphate in vitro (TPP effect). ETK activated by TPP in vitro (AETK) was related to ETK by a linear regression of slope greater than or equal to 1, implying that transketolose apoenzyme (apoTK) was constant or decreased as ETK decreased. For most patient groups the value of apoTK was 0.1 U/g and the slope 1.033 to 1.050. In the subgroup of non-vomiting drinkers with Wernicke's encephalopathy (WE), the slope of the linear regression of AETK on ETK was 1.21, so that apoTK decreased as ETK decreased. Comparison of these data is consistent with a difference in the TK of WE drinkers from that of others. Generally, any variation of TPP effect was due only to variation of ETK. We recommend measurement of ETK, without TPP effect, for the assessment of thiamine nutrition.

Review of the genotoxicity and carcinogenicity of 4,4'-methylene-dianiline and 4,4'-methylene-bis-2-chloroaniline

4,4'-Methylene-dianiline (MDA) and 4,4'-methylene-bis-2-chloroaniline (MOCA) are polycyclic aromatic amines that are currently used in industry. Both compounds have been found to be bacterial mutagens and to be positive in a number of assays for genotoxicity. In animal studies, MDA has induced thyroid and liver neoplasms while exposure to MOCA resulted in a variety of tumors including those of the liver, mammary gland and bladder. Epidemiologic proof of human carcinogenicity of both compounds is lacking; however, there is evidence that MOCA can be metabolized to mutagenic products by human tissue. In this paper, the major finding concerning the biotransformation, genotoxicity and carcinogenicity of MDA and MOCA are reviewed.

Balloon dilatation versus surgical revision of infra-inguinal autogenous vein graft stenoses: long-term follow-up

Although infra-inguinal autogenous vein graft stenoses may be treated by balloon dilatation (PTA) or surgical revision, the optimal approach is undefined. Over the last 7 years 24 PTA procedures were performed on 37 vein graft stenoses in 19 grafts. Graft stenoses were diagnosed from 2 to 72 (mean = 17.3) months after implantation. PTA was successfully completed in 23 (96%) of the 24 procedures including 18 (95%) of the primary, and 5 (100%) of the secondary procedures. Recurrent vein graft stenosis or graft thrombosis developed in 12 (67%) grafts from 3 to 47 (mean = 12.5) months after primary PTA. Long-term patency after primary PTA was 69% at 6, 29% at 12, and 22% at 36 months; secondary patency was 81% at 6, 45% at 12, and 27% at 36 months. During the same period vein graft stenosis in 7 fem-pop and 2 fem-tib grafts were surgically revised with an initial success rate of 100%, and 2 (22%) complications. Four (44%) of these grafts occluded from 1-17 (mean 6.2) months after repair, yielding a primary 5-year patency of 62%. Although vein graft stenosis may be safely, effectively, and repeatedly treated with PTA, long-term durability appears to be superior after surgical revision.

Inhibition of repair of O6-methyldeoxyguanosine and enhanced mutagenesis in rat-liver epithelial cells

The pro-mutagenicity of chemically-induced methylation of DNA at the O6 position of deoxyguanosine was studied in cultured adult rat liver epithelial cells. To modify the level of O6-methyldeoxyguanosine (O6-medGuo) resulting from exposure to an alkylating agent, partial depletion of the O6-alkylguanine-DNA alkyltransferase (AGT) repair system was produced by pretreatment of ARL 18 cells with a non-toxic dose of exogenous O6-methylguanine (O6-meG). Exposure of cells to 0.6 mM O6-meG for 4 h depleted AGT activity by about 40%. Intact and pretreated cells were exposed to a range of doses of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), and mutagenesis at the hypoxanthine-guanine phosphoribosyl transferase (HGPRT) locus was quantified by measurement of 6-thioguanine-resistant mutants. The mutagenicity of MNNG was dose dependent and was greater in O6-meG pretreated cultures than in intact cultures. Immunoslot blot measurement of O6-medGuo employing a mouse monoclonal antibody demonstrated that MNNG produced O6-medGuo and that the intact liver cells were efficient in eliminating this lesion from their DNA. Since depletion of AGT would be expected to affect the rate of elimination of only O6-medGuo, it is concluded that this lesion is highly pro-mutagenic.

Superior mesenteric vein inflow for liver transplantation when the portal vein is occluded

An alternative solution to the problem of liver transplantation in the patient with an occluded portal vein is described. It uses a bridge graft of donor iliac vein from the superior mesenteric vein at the base of the colonic mesentery. The graft is tunnelled over the pancreas and under the stomach to the region of the liver hilum to provide portal inflow. This procedure was employed successfully in four patients, with patency for more than 2 years in the patient with the longest follow-up. By this approach it is routinely possible to perform a transplant procedure in a recipient with an occluded portal vein.

Effects of the peroxisome proliferator di(2-ethylhexyl)phthalate on enzymes in rat liver and on carcinogen-induced liver altered foci in comparison to the promoter phenobarbital

The livers of rats given either the peroxisome proliferating hepatocarcinogen di(2-ethylhexyl)phthalate (DEHP) following initiation by 2-acetylaminofluorene (AAF) or the neoplasm promoter phenobarbital (PB) were studied for changes in 8 histochemical properties. Male F344 rats were fed 200 ppm AAF for 7 weeks to induce hepatocellular altered foci, and were then fed diets containing either no chemical, 12,000 ppm DEHP or 500 ppm PB for 24 weeks. In hepatocytes, DEHP increased alkaline phosphatase activity throughout the lobule, but reduced gamma-glutamyltransferase (GGT) activity in periportal hepatocytes. PB, in contrast, increased GGT activity in periportal hepatocytes. In foci that were induced by AAF, DEHP reduced the histochemical activity of GGT and did not increase the number, mean volume or volume % of foci detected by deficiencies in iron storage, glucose-6-phosphatase, adenosine triphosphatase or fibronectin. PB enhanced the expression of all 8 phenotypic abnormalities in foci such that either more profiles were detected or the area of foci was increased.

Carcinogenicity tests of fecapentaene-12 in mice and rats

Fecapentaenes, a class of direct-acting bacterial mutagens, have been isolated from the feces and intestinal tract of humans on a Western meat-containing diet. Two bioassays to test pure fecapentaene-12 (FP-12) for carcinogenicity were performed. FP-12 in dimethylsulfoxide (DMSO) solution was injected i.p. into newborn ICR/MA mice on days 1, 3, 7, 10, 14 and 21. The mice killed after 21 months had neoplasms in liver, lung, glandular stomach and subcutaneous fibrosarcoma. Intrarectal (i.r.) infusion of FP-12 in an aqueous vehicle into male F344 rats for 71 weeks, and killing the rats after 21 weeks more, displayed no evidence of neoplasia associated with FP-12 exposure. The positive control, N-nitrosomethylurea (NMU), given i.r. as 4 2-mg doses in 2 weeks, as expected, yielded multiple colonic neoplasms in less than 11 months. Fecapentaene may exert its effect in bacteria and in newborn mice through the generation of hydroxy radicals. However, adult rodent and human colon may have adequate biochemical defense mechanisms against low level, even continuous exposures to chemicals like FP-12, and thus be at low risk of neoplasia, as was found.

Types and amounts of carcinogens as potential human cancer hazards

Current knowledge on the mechanisms of chemical carcinogenesis forms the basis for application of select short-term in vitro and in vivo tests to detect potential human carcinogens, for ultimate application to hazard assessment. Chemical carcinogenesis involves a series of distinct steps, proceeding from the initiation of a neoplastic cell, through its promotion, development, and progression to cancer. Some chemicals act in each of these stages as initiators, cocarcinogens, promoters, or inhibitors of carcinogenesis. Chemicals can be classified as operating by genotoxic or epigenetic mechanisms, and appropriate tests can be used to detect such properties. These abbreviated tests provide enhanced qualitative decision-making potential since they are based on mechanisms of action. Advances in molecular biology may provide additional tests to detect cancer risk. The quantitative data available from in vitro dose-response studies indicate that carcinogenic effects are dose dependent and, therefore, a threshold or no-effect level probably exists, which is low for potent carcinogens (especially genotoxins) and high for weaker ones (particularly epigenetic agents).

Structure-activity relationships in the rat hepatocyte DNA-repair test for 300 chemicals

312 chemicals/mixtures were tested for genotoxicity in the rat hepatocyte/DNA-repair test. A variety of structure-activity relationships was evident. Of the 309 pure chemicals, 142 were positive. Of these, 43 were judged by IARC to have sufficient or limited evidence of carcinogenicity and none of the remainder was a proven noncarcinogen. Among the 167 negative chemicals, 44 were carcinogens. Some of these are known to be genotoxic in other systems, but based on several lines of evidence, many are considered to be epigenetic carcinogens that lack the ability to react with DNA and rather lead to neoplasia by nongenotoxic mechanisms.

Glutamine synthetase heterogeneous expression as a marker for the cellular lineage of preneoplastic and neoplastic liver populations

The distribution of glutamine synthetase (GS) in rat liver and in putative preneoplastic and neoplastic lesions was studied at stages of hepatocarcinogenesis induced by diethylnitrosamine (DEN), 2-acetylaminofluorene (AAF) and aflatoxin B1 (AFB1) using immunohistochemistry. In control rats, GS was localized entirely to rings 1-3 cells deep surrounding the central veins. Exposure to DEN or AAF resulted in a reduction of these GS-positive (GS+) zones by 96 and 61% respectively, due to necrosis of the cells in this compartment, while AFB1 had little effect (less than 14%). At later times GS+ foci, adenomas and carcinomas developed in animals exposed to DEN or AAF, but not AFB1, corresponding to the acute effects. Small GS+ foci also identified by other phenotypic abnormalities (e.g. gamma-glutamyltransferase) were exclusively associated with the regenerating GS+ zone as were a few collections of GS+ hepatocytes, the nature of which was uncertain. Although accounting for a very small fraction (less than 3%) of total foci, these GS+ foci or GS+ hepatocytes apparently gave rise to a substantial fraction of adenomas that were GS+ (DEN: 43% and AAF: 33%) and an even higher percentage of GS+ carcinomas (DEN: 59% and AAF: 39%). No GS+ neoplasms were induced by AFB1. Statistical evaluation of these data strongly suggests that GS+ neoplasms originate through initiation of hepatocytes which possess this particular phenotype. Thus, GS might serve as a specific marker for tracing cell lineage relationships during hepatocarcinogensis. The GS+ phenotype which confers glutamine independence may also provide a growth advantage.

Lymphoscintigraphy to confirm the clinical diagnosis of lymphedema

Confirmation of the diagnosis of lymphedema often requires lymphangiography, a procedure that is painful for the patient and technically demanding. Radioisotope lymphoscintigraphy is a relatively new technique that uses technetium 99 m antimony trisulfide colloid to produce a diagnostic image similar to a lymphangiogram. The procedure requires a single subcutaneous injection in the involved extremity, and images are obtained 3 hours later. It is technically easy to perform, produces minimal discomfort for the patient, and has no adverse effects. We have recently used radioisotope lymphoscintigraphy to evaluate 17 patients with extremity edema. These patients initially had a presumed diagnosis of lymphedema involving the upper or lower extremity. Lymphoscintigraphy confirmed the diagnosis of lymphedema in 12 (70.6%) patients. In five of the 17 patients (29.4%) the clinical impression of lymphedema was not supported by lymphoscintigraphy, leading to alternative diagnoses such as lipomatosis, venous insufficiency (two patients), congestive heart failure, and disuse edema. In all patients with secondary lymphedema the lymphatic system in the involved extremity could be partially visualized. Conversely, three of four patients with primary lymphedema had no ascent of the tracer from the foot and no lymphatic channels could be visualized. Lymphoscintigraphy is relatively easy to perform, safe, minimally invasive, and not uncomfortable for the patient. It is useful in differentiating lymphedema from other causes of extremity edema, allowing institution of appropriate therapy.

Superior gluteal artery steal syndrome

A sacral ulcer is described where ischaemia due to a vascular "steal" syndrome in the gluteal angiotome was the cause of persistent failure of flap reconstruction. Thrombotic obliteration of the abdominal aorta had resulted in the development of collaterals which, paradoxically, deprived the flaps based on standard angiotomes of their major source of blood supply, as they became the major source of perfusion for the legs. Healing of the ulcer was successfully achieved only after aorto-iliac reconstruction. Two other cases of ischaemic sacral ulceration, associated with aortic occlusion, are described.

Percutaneous laser probe femoropopliteal angioplasty: a preliminary experience

Percutaneous laser probe "hot tip" angioplasty procedures were performed on 47 occluded femoropopliteal artery segments in 27 men and 10 women ranging in age from 31 to 92 (mean, 64.7) years. Indications for the procedure included claudication in 29 (78%) segments, and the occlusion lased was greater than 7 cm in length in 51% of the procedures. Failure to recanalize the occlusion occurred in 14 (30%) segments, and recanalization followed by in-hospital reocclusion occurred in seven (15%) segments, yielding an initial failure rate of 45%. Initial failures were noted in 40% of the less than 3 cm occlusions, 33% of the 4 to 7 cm occlusions, and 54% of the greater than 7 cm occlusions. In nine (43%) instances in these 21 failures there was extension of the occluded segment or decline of the ankle/brachial index or both, precipitating the need for surgery in three (18%) of these 17 patients. Among the successfully treated group, 17 (65%) of these vessels in 15 patients reoccluded from 1 to 14 (mean, 3 1/2) months after the procedure. Cumulative patency among the successfully lased vessels was 69% at 1-month, 38% at 6 months', 29% at 12 months', and 14% at 15 months' follow-up. Fifteen-month patency was 7% of the entire series of 47 vessels treated. Eighteen complications occurred after 15 (32%) of these 47 procedures. Based on these results, the widespread application of laser probe angioplasty cannot be justified without further clinical and laboratory investigation.