Maternal atherogenic diet in swine is protective against early atherosclerosis development in offspring consuming an atherogenic diet post-natally.

Atherosclerosis found early in life suggests that it may arise from fetal adaptations during development in utero. We evaluated the effect of a maternal atherogenic diet on atherosclerosis development in offspring. Aortic fat deposition was evaluated by Sudan IV staining and coronary atherosclerosis was assessed histologically. Sows were fed an atherogenic diet (ath) or standard diet (std) throughout gestation. Twelve neonates (six per maternal diet group) were evaluated with no significant differences noted (P>0.05) in serum lipids or aortic fat deposition and there was no evidence of coronary atherosclerosis. Twenty offspring (10 per maternal diet group) were followed for 5 months forming the pubertal age group. Half of these swine received an atherogenic (ATH) diet (std-ATH and ath-ATH) and half received a standard (STD) diet (std-STD and ath-STD). Pubertal age swine on the ATH diet had significantly greater (P<0.05) serum lipids and aortic fat deposition compared with those on the STD diet, with significantly greater fat deposition (P<0.05) occurring in the std-ATH versus ath-ATH group. Coronary atherosclerosis was exhibited only in the std-ATH diet group. Our findings suggest that gestational diet may alter the body's management of cholesterol later in life, possibly providing a protective effect from atherosclerosis.

Carbon dioxide digital subtraction angiography: the practical approach.

CO(2) has developed into a viable alternative to iodinated contrast for digital vascular imaging. Because CO(2) is a gas, it has a unique set of properties that affords certain advantages over iodinated contrast in a variety of settings. However, if CO(2) is used inappropriately, these same properties are associated with a unique set of rare but potentially harmful events. Therefore, it is essential that these unique characteristics be understood in order to employ a few simple precautionary measures. Fortunately, there is a delivery system currently available that is readily assembled and easy to use that ensures the appropriate administration of CO(2). This system, combined with experience, can reduce the greater labor intensity sometimes associated with CO(2) digital subtraction angiography. When it is used appropriately, CO(2) digital subtraction angiography alone or in combination with iodinated contrast offers diagnostic and interventional rewards that are not available with traditional intravascular contrast examinations.

Laparoscopic and percutaneous radiofrequency ablation of the kidney: acute and chronic porcine study.

OBJECTIVES: The chronic effects of renal radiofrequency ablation are unknown. Herein, we investigate the anatomic and physiologic sequelae of laparoscopic and percutaneous renal radiofrequency ablation in acute and chronic porcine models. METHODS: Our study comprised two phases-an acute phase and a chronic phase. In the acute phase, bilateral laparoscopic renal radiofrequency ablation was performed in 6 animals (12 renal units), which were euthanized immediately after surgery. In the chronic study, bilateral percutaneous renal radiofrequency ablation was performed in 5 animals (10 renal units). One animal each was euthanized at postoperative day 3, 7, 14, 30, and 90. RESULTS: Ultrasound-monitored laparoscopic (n = 12) and percutaneous (n = 10) radiofrequency ablations of the lower pole of the kidney were technically successful in each instance. No intraoperative complications occurred. In the survival experiments, the radiolesions showed gradual spontaneous resorption and ultimate renal autoamputation, while maintaining pelvocalyceal integrity as confirmed by ex vivo retrograde ureteropyelogram. Serum creatinine and hematocrit remained stable in all survival animals. Postoperative complication occurred in 1 chronic animal with nonobstructive small bowel dilation at autopsy. CONCLUSIONS: Laparoscopic and percutaneous renal radiofrequency ablation are technically feasible. The anatomic and physiologic sequelae of renal radiosurgery are favorable. Improved techniques of real-time monitoring of the evolving renal radiolesion are necessary.

Aortic prosthetic graft infections: radiologic manifestations and implications for management.

Prosthetic graft infections are an uncommon complication of aortic bypass. These infections may have serious sequelae such as limb loss and can be lethal. They are hard to eradicate and, under certain circumstances, difficult to diagnose. Usually, computed tomography (CT) is the most efficacious imaging method for diagnosis of graft infections due to its quick availability. The sensitivity of magnetic resonance imaging in detection of perigraft infection has not been thoroughly investigated but is probably similar to that of CT. After the early postoperative period, persistent or expanding perigraft soft tissue, fluid, and gas are the CT findings of graft infection. Aortoenteric fistula should be considered a subset of aortic graft infection; however, perigraft air is more likely to be seen with an aortoenteric fistula. Other conditions associated with graft infection include pseudoaneurysm, hydronephrosis, and osteomyelitis. Adjunctive studies such as sinography, ultrasonography, gallium scanning, and labeled white blood cell scanning can be quite useful in diagnosis, determination of the extent of disease, and selection of the treatment modality. White blood cell scanning is an important complementary test to CT in ambiguous cases, such as in the early postoperative period, and may be more sensitive in detection of early graft infection.

Relative ultrasonographic echogenicity of standard, dimpled, and polymeric-coated needles.

PURPOSE: To use quantitative ultrasonographic measurements to compare the effect of a polymeric coating designed to increase needle echogenicity to commercially available needles. MATERIALS AND METHODS: Commercially available standard smooth and dimpled echogenic tip 21-gauge needles established reference levels of echogenicity in gelatin-based and turkey breast phantoms. Examples of both types of needles were coated with a thin polymeric film that utilizes entrapped microbubbles of air on its surface to increase echogenicity. Samples of each type in both coated and noncoated versions were placed in phantoms in matched positions and imaged with clinical ultrasound machines. Similar numbers of each category were evaluated at various angles of insonation for a total of 109 images. Similar numbers of each category were imaged at 5-minute intervals for up to 38 minutes for a total of 226 images. Images were recorded, digitized, and evaluated for relative echo strength in arbitrary echogenic brightness units. RESULTS: Coating increased peak echogenicity over the entire needle to a level that closely approximates the peak echogenicity of dimpled needle tips (means: dimpled = 834, coated smooth = 803, coated dimpled = 823; P = .54). Smooth is lower than this group at 468 (P = .0001). Representative area echogenicity increased with coating or dimpling (smooth = 377 vs coated smooth = 778, coated dimpled = 690, dimpled = 775; P = .0001). Coating increased peak values 74% and area values 95% compared to smooth. Decreased angles of insonation moderately reduced echogenicity on coated smooth, coated dimpled, and dimpled, while it decreased to below good visibility threshold on standard smooth needles. The echogenicity of the coated needles fades in saline with time (1%/min). CONCLUSION: Objective measurements show that this coating significantly increases echogenicity of entire needles to match that obtained with a dimpled tip.

Complications and technical limitations of hepatic arterial infusion catheter placement for chemotherapy.

PURPOSE: To determine the rate of complications associated with hepatic arterial infusion (HAI) catheter placement, as well as technical success related to liver perfusion. MATERIALS AND METHODS: The authors reviewed 44 patients who underwent 106 HAI catheter placements, including 15 men and 29 women with an average age of 55 years (range, 32-82 years). One to nine placements were performed per patient with 61 (58%) via the left brachial artery, 40 (38%) via the right femoral artery, and five (4%) via the left femoral artery. Chemoinfusion lasted 4 days, with initial catheter placement assessed on technetium-99m macroaggregated albumin (MAA) perfusion scans, as well as daily abdominal radiographs. RESULTS: One hundred attempted hepatic arterial catheter placements were completed. Liver perfusion was global in 66 (66%) cases, in the right lobe only in 28 (28%) cases, and in the left lobe only in six (6%) cases. Eight (8%) had gastrointestinal (GI) tract perfusion; this was eliminated in seven cases (7%) after catheter repositioning. Forty-six (43%) placement attempts required embolization of 62 GI vessels to preclude GI chemoinfusion. Complications included one cerebrovascular accident (related to removal of a left brachial catheter), eight brachial artery thromboses (four that required emergent thrombectomy), six hepatic arterial dissections, four hepatic arterial thromboses, and four catheter malfunctions. CONCLUSIONS: HAI catheter placement via the left brachial artery has increased complications. Nearly one-half of placements required embolization of GI vessels to preclude GI perfusion. Global perfusion is possible in two-thirds of cases.

Thrombolytic enhancement with perfluorocarbon-exposed sonicated dextrose albumin microbubbles.

Whereas low-intensity, high-frequency ultrasound (US) alone appears to cause minimal thrombolysis, US combined with air-filled microbubbles does increase the amount of urokinase (UK)-mediated clot lysis (CL). Because this phenomenon may be mediated by cavitation-induced streaming, we hypothesized that perfluorocarbon-exposed sonicated dextrose albumin (PESDA) microbubbles, which are more stable than air-filled microbubbles, may also enhance US-induced thrombolysis. We measured the percentage CL of equally sized thrombi (1.0 +/- 0.1 mg) made from freshly drawn blood incubated for 2 hours and then exposed to 20 kHz US (0.846 MPa peak negative pressure). The thrombi were bathed in 4 ml of saline solution, UK alone (20,000 U), PESDA alone, or a combination of PESDA with UK. The percentage CL achieved with PESDA and therapeutic US was also compared with the percentage CL achieved with room air-filled sonicated dextrose albumin (RASDA) microbubbles. When compared with US alone (24% +/- 13% CL) or UK alone (17% +/- 3% CL), PESDA plus US produced significantly better CL (43% +/- 17%; p< 0.05). PESDA combined with US also produced significantly greater CL than RASDA combined with US (28% +/- 9%; p < 0.05). The optimal CL was achieved with a combination of PESDA with UK with US (60% +/- 14% CL). We conclude that PESDA microbubbles alone may be capable of inducing thrombolysis when insonified with a low-frequency transducer.

Biliary strictures in liver transplant recipients: treatment with metal stents.

PURPOSE: To determine initial and long-term results of metal stent placement in biliary strictures that failed to respond to balloon dilation. MATERIALS AND METHODS: Sixty-one metal stents were placed in 36 liver transplant recipients (age range, 3 months to 71 years) with biliary strictures that failed to respond to balloon dilation. Patients were followed up for up to 5 years. RESULTS: Initial stent placement was successful in all patients. Primary patency was 44% at 3 years and was 0% at 5 years; secondary patency was maintained at 88% at those intervals. Patency associated with the Gianturco Z stent was superior to that with the Palmaz stent. Stents located at anastomotic sites had higher patency rates than those at nonanastomotic sites. Major stent-related complications occurred in eight patients and included two pediatric deaths. CONCLUSION: Metal stents can be useful in the short term but have limited patency, often require repeat intervention, and have substantial complications. Long-term success depends heavily on repeat interventions or stent removal.

Awakenings to the pathogenicity of urease and the requirement for continuous long term therapy.

Urease is an enzyme found in plants and bacteria, but not mammals. It catalyzes the conversion of urea to carbon dioxide and ammonia. Ammonia shortens the life span of cells; and higher concentrations cause tissue necrosis and cytolysis. Twenty percent of total body urea is converted to ammonia by bacterial urease in the colon. Small injections of urease immunize animals by producing antiurease, a gamma globulin, which inactivates urease. Immunization eliminates the colonic conversion of urea to ammonia. Injection of urease produces ammonia intoxication making immunization hazardous. Although previously impossible, a non enzymatic urease antigen was synthesized by covalently bonding jack bean urease with glutaraldehyde. This antigen stimulated the production of antiurease that inactivates native urease. Helicobacter pylori, a potent urease producer, has been implicated in peptic ulcer, gastritis and other inflammatory bowel lesions. The pathogenicity of H pylori is dependent on its urease production. Immunization to urease can render H pylori non pathogenic. Cirrhotics develop encephalopathy and hyperammonemia because their livers fail to convert all the ammonia in portal venous blood to urea and collaterals develop by passing the liver. Colonic ammonia increases the turnover rate of colonic mucosa. Ammonia absorbed into the portal venous system is transported to the liver where it is reconverted to urea. Absorbed ammonia adversely influences liver function. Infections with urease producing organisms destroy the renal parenchyma and produce struvite stones. Urease immunization aids colonic healing and prevents uremic colitis. Absorbed ammonia is a noxious influence on the liver. Animals immunized to urease regenerate the liver faster and are less susceptible to hepatotoxins. Immunization to urease ameliorates cirrhosis. Proteus and other urease producers become non toxic and do not damage the renal parenchyma. Urease is responsible for the pathogenicity of infections with urease producing organisms. Immunization to urease renders urease producing organisms non pathogenic.

Ultrasound-assisted thrombolysis.

RATIONALE AND OBJECTIVES: Current use of thrombolytic agents to lyse thrombus, though safe, is complicated by stroke, bleeding, and clot embolization. Therapy may be protracted, resulting in further ischemia and possible tissue loss. Peripheral arterial and graft occlusions often require several hours of thrombolytic therapy, which may occasionally exceed 48 hours and may also require expensive intensive care monitoring. It is desirable to accelerate clot lysis and to thereby reduce the risks and costs associated with the procedure and minimize morbidity. In this article, the authors propose the use of intravascular ultrasound in conjunction with thrombolytic agents to increase the rate of thrombolysis. METHODS AND RESULTS: In-vitro thrombolysis of fresh human blood clots was studied with and without urokinase by using continuous wave, 20-KHz ultrasound at the power levels 1-2 watts. Loss in weight of each clot was used to measure the extent of thrombolysis. Clot lysis was observed when ultrasound and thrombolytic agents were used alone. At modest power levels of 1.0 to 1.5 watts of ultrasonic energy a significant increase in lysis was observed in conjunction with 5,000 units of urokinase. CONCLUSIONS: In the short treatment duration of this in-vitro study, 5,000 units of urokinase combined with 20-KHz ultrasound energy at 1.0 and 1.5 watts was associated with a greater percentage thrombolysis by weight than either urokinase or ultrasound alone.

An unopened titanium Greenfield IVC filter: intravascular ultrasound to reveal associated thrombus and aid in filter opening.

A titanium Greenfield filter did not open following placement in the infrarenal inferior vena cava (IVC). Abdominal radiograph and cavogram showed no definite reason for filter malfunction. Intravascular ultrasound (IVUS) demonstrated the unopened filter in the IVC with thrombus binding the legs. The thrombus was disrupted with a catheter, and the filter completely expanded with a balloon. IVUS documented full-filter opening in addition to residual thrombus in the filter following manipulation.

Effectiveness of a prolapsed bird's nest filter.

PURPOSE: The authors evaluated the variable deployment of the Bird's Nest filter, including frequency and extent of prolapse in clinical use, and analyzed the effects of this variability on clot-trapping efficiency with an in vitro model. MATERIALS AND METHODS: In the clinical placement of 20 filters, the average length of cephalic filter wires from the center of the filter was measured from radiographs obtained immediately after placement. To analyze the effects of prolapse, a variable-rate pump was used to mimic the effects of respiration on IVC flow. Four clot sizes (5 x 20, 5 x 40, 10 x 20, and 10 x 40 mm) were evaluated with four filter configurations with wires stretched to different lengths in a cephalic direction from the center of the filter: 2 cm (normal-tight), 5 cm (normal-loose), 8 cm (moderate prolapse), and to a maximum of 12 cm (maximum prolapse). Ten passes for each clot size were performed with each filter configuration in both the horizontal and vertical positions. The smallest clots were also tested with a slower constant-rate pump. RESULTS: In clinical use, the average length of the filter wire was 5.4 cm (range, 1.2-9.0 cm). With the variable flow pump, the in vitro degree of prolapse did not significantly decrease the trapping efficiency for any but the smallest (5 x 20-mm) clots, for the maximum prolapse configuration in the horizontal position (P = .01). In addition, for these clot sizes, the filter was more efficient with the slower constant rate compared with the faster variable rate; this difference was only statistically significant in the horizontal position for the maximum prolapse configuration (P = .007). CONCLUSION: The results suggest that in clinical practice, a prolapsed Bird's Nest Filter remains effective for all but small clots.

Inhibition of smooth muscle cell proliferation and experimental angioplasty restenosis by beta-cyclodextrin tetradecasulfate.

Heparin inhibits smooth muscle cell proliferation in vitro, a property that makes it potentially useful in preventing restenosis after angioplasty. Its utility in this setting is limited by the inability to use high doses (secondary to anticoagulant effects) and the need for subcutaneous administration. We tested the ability of beta-cyclodextrin tetradecasulfate (CDT), a nonanticoagulant synthetic heparin mimic, to inhibit smooth muscle cell proliferation in vitro and tested its efficacy when orally administered for the prevention of angioplasty restenosis in a rabbit atherosclerosis model. Vascular smooth muscle cells were cultured from rabbit aortas by the explant technique. Passaged cells were plated at low density in microtiter plates in the presence or absence of varying concentrations of heparin or CDT in culture medium containing 10% fetal calf serum. Using both 3H-thymidine incorporation and total protein assays, both heparin and CDT caused a similar dose-dependent inhibition of proliferation. We next tested the effect of orally administered CDT in the prevention of restenosis in focal femoral artery arteriosclerotic lesions created in hypercholesterolemic New Zealand White rabbits by air-dessication endothelial injury and subsequent peripheral angioplasty. Animals were followed up for 1 month and were fed normal chow supplemented by tap water with or without CDT. In animals receiving the highest concentration of CDT (2 mg/mL drinking water), the percentage of arterial cross-sectional area with intimal hyperplasia decreased from 50.5 +/- 1.7% (control) to 26.9 +/- 2.2% (p < 0.001), with the intimal/medial ratio being decreased from 1.4 +/- 0.4 to 0.5 +/- 0.2 (p = 0.056).(ABSTRACT TRUNCATED AT 250 WORDS)

The mythology of povidone-iodine and the development of self-sterilizing plastics.

The predominance of elemental iodine as a chemical antiseptic has been established during a century. Free iodine is effective for treatment and prevention of infection. Iodophors, such as povidone-iodine, have replaced elemental iodine in clinical use. Toxic absorption of povidone-iodine occurs from all tissues except intact adult skin, to which its use should be restricted. Povidone-iodine binds iodine so firmly that insufficient free iodine is released to be effective for treating or preventing infection. It is a weak antiseptic that is marginally acceptable as a disinfectant for adult skin. The shortcomings of povidone-iodine stimulated a search for iodophors that would liberate therapeutically effective concentrations of free iodine. These investigations led to a new self-sterilizing plastic formed by the complexing of polyurethane and iodine.

Restenosis and successful angioplasty: histologic-radiologic correlation.

Histologic analysis was undertaken on 24 perfusion-fixed arteries from New Zealand White rabbits that had undergone percutaneous transluminal angioplasty (PTA) of a focal arteriosclerotic lesion in the femoral artery 1 month earlier. Experiments representative of occlusion, restenosis (greater than or equal to 50% stenosis), a good result (less than 50% stenosis), or aneurysm (as defined angiographically) were randomly selected for histologic analysis. Histologic findings were compared with those in untreated control lesions in the contralateral femoral artery. All good results (n = 11) but only four of seven restenoses had histologic evidence of a tear into the tunica media or the tunica adventitia (P = .017). Cases of tears to the adventitia were more likely to have a good result. New myointimal proliferation was more severe with restenosis (P less than .05). Occlusions and aneurysms appeared to be more severe expressions of the histologic findings observed in restenoses and good results, respectively. An arterial tear is necessary but not sufficient to obtain a good result after PTA; outcome is ultimately dependent on the degree of intimal hyperplasia.

Shear stress in the performance of esophageal dilation: comparison of balloon dilation and bougienage.

While both the balloon catheter and the bougie are effective for esophageal dilation, each has its proponents. From a biomechanical point of view, the two methods should differ significantly, since bougienage depends on advancing a tapered dilator to generate radial force and balloon catheter dilation depends solely on balloon inflation to generate its radial dilating force. In a series of equivalent esophageal stenoses made by suture plication in swine esophageal segments, the authors measured shear force and radial force generated by dilation with a Maloney bougie, a Savary-Gilliard bougie, and an esophageal balloon. The mean radial forces generated were 6.42, 4.46, and 4.04 N, respectively, which did not differ significantly. However, the mean shear forces measured were 16.92, 6.92, and 1.44 N, respectively. The shear force with the Maloney bougie differed significantly from that with the Savary-Gilliard and the balloon and was on the same order of magnitude as the tensile strength of the esophagus (25-27 N). The shear force with the balloon was significantly lower than that with either bougie. In theory, the reduced shear force associated with balloon dilation might reduce the risk of esophageal perforation, but safety will have to be determined in clinical trials.