Results of bypasses to the anterior tibial artery through the interosseous membrane

Two month-old Wistar male albino rats were exposed during a 30-day period to a daily oral intake ad libitum of either 200 microg/mL Cd (as CdCl2), 0.1 microg/mL Se (as Na-selenite), or the same dosages of Cd + Se in drinking water. The daily intake from the water was calculated to be 15 mg Cd/kg and 7 microg Se/kg. Cadmium (Cd) accumulates in the heart (p < 0.005) and, in rats, decreases both body mass growth (p < 0.005) and heart mass (p < 0.02). Selenium (Se) significantly decreases the negative effect of Cd on body mass growth. In the hearts of Cd-treated rats, cadmium caused the decrease (p < 0.05) of selenium-dependent glutathione peroxidase (GSH-Px, EC 1.11.1.9) activity. At the same time, the activities of total superoxide dismutase (total SOD, EC 1.15.1.1), manganese-containing superoxide dismutase (Mn SOD), and copper-zinc-containing superoxide dismutase (CuZn SOD) were increased (p < 0.005). The activities of total SOD, CuZn SOD (p < 0.005), GSH-Px (p < 0.02), and glutathione-S-transferase (GST, p < 0.005) were increased in the hearts of Se-treated rats. However, by concomitant administration of Cd and Se, these changes were diminished (total SOD, GST) or were completely eliminated (Mn SOD, GSH-Px). These results indicate that Se only partly diminishes the effects of Cd cardiotoxicity.     

Differential response of arteries and vein grafts to blood flow reduction

BACKGROUND: Because the relative efficacy of antiarrhythmic agents on halothane-epinephrine arrhythmias has not been well characterized, this study was undertaken to comparatively evaluate the antiarrhythmic action of Na(+)-, K(+)- and Ca(2+)-channel blockers on epinephrine-induced ventricular arrhythmias during halothane anesthesia in rats. METHODS: Rats were anesthetized at random with either halothane (1.5%), isoflurane (2.0%), or pentobarbital (50 mg/kg intraperitoneally), and the lungs were mechanically ventilated with oxygen. The rats were studied in three consecutive protocols. Protocol I determined the arrhythmogenic thresholds of epinephrine during the three types of anesthesia in 33 rats. Protocol II determined the arrhythmogenic thresholds of epinephrine during halothane anesthesia in 64 rats receiving saline (control) or one of five antiarrhythmic agents. Protocol III measured the duration of epinephrine-induced arrhythmias during halothane anesthesia in 42 rats receiving saline (control) or one of five antiarrhythmic agents. RESULTS: In protocol I, the arrhythmogenic doses of epinephrine during halothane, isoflurane, or pentobarbital anesthesia were 1.7 +/- 3.2, 11.1 +/- 0.6, and 39.0 +/- 3.9 micrograms/kg, respectively, and the corresponding plasma concentrations were 4.3 +/- 0.8, 103.7 +/- 9.2, and 246.7 +/- 28.9 ng/ml, respectively. In protocol II, the arrhythmogenic doses were similar in rats receiving saline and in those receiving lidocaine. The arrhythmogenic doses in rats receiving verapamil, flecainide (Na(+)- and K(+)-channel blocker), E-4031 (K(+)-channel blocker), or amiodarone(K(+)-channel blocker with Na(+)-, Ca(2+)-, and beta-blocking activity) increased significantly, i.e., 4.2, 4.2, 5.5, and 31.7 times control (P < 0.01). In protocol III, lidocaine had no effect on the duration of arrhythmias. Flecainide, E-4031, and verapamil markedly reduced the duration of arrhythmias induced by epinephrine, 8 micrograms/kg intravenously (P < 0.01), whereas only amiodarone markedly reduced the duration of arrhythmias induced by epinephrine, 16 micrograms/kg intravenously (P < 0.01). CONCLUSIONS: It was concluded that agents with K(+)-channel blocking properties were the most effective in preventing halothane-epinephrine arrhythmias in rats.     

Long-term results of femorotibial bypass with vein or polytetrafluoroethylene

OBJECTIVE: The purpose of this study was to determine predictors of posttraumatic stress disorder (PTSD) in health care workers exposed to a disaster, in order to facilitate early case identification and prevention of subsequent morbidity. METHOD: Following an air disaster, 355 military medical health care workers were studied over an 18-month follow-up period. Measures included assessment of peritraumatic reactions associated with the disaster, the frequency of other stressful events after the disaster, and standard PTSD rating scales at 6, 12, and 18 months. RESULTS: Multivariate logistic regression of data on health care workers who cared for victims of the air disaster showed that PTSD was more likely to develop in those who had not completed college, those who had worked with burn victims, those who had experienced more stressful life events in a period of approximately 6 months following the disaster, and those who experienced emotional numbness immediately after the disaster. CONCLUSIONS: Results suggest that lower levels of education, exposure to grotesque burn injuries, stressful life events following exposure, and feelings of numbness following exposure are useful predictors of subsequent development of PTSD.     

Treatment of thrombus containing lesions in diseased native coronary arteries and saphenous vein bypass grafts using the AngioJet Rapid Thrombectomy System

The occurrence of fresh thrombus during percutaneous coronary interventions, especially in patients with diffusely diseased saphenous vein bypass grafts is associated with an increased incidence of procedural complications and clinical events. The AngioJet Rapid Thrombectomy Catheter was designed to remove thrombus via a Bernoulli effect induced vacuum. Here we report on the technical aspects of the device and the AngioJet thrombectomy procedure. Indications and potential complications, both procedure- and device related are discussed.     

Internal jugular to axillary vein bypass for subclavian vein thrombosis in the setting of brachial arteriovenous fistula

Relatively little is known about the epidemiology of carcinoid tumours in contrast to the extensive information available on their biochemical effects and natural history. Accordingly, we have used cancer registrations in England from 1979 to 1987, and in Scotland from 1980 to 1989, to estimate the incidence of carcinoid tumours in Britain. Age-standardised incidence rates for England, based on 3,382 registrations, were 0.71 (0.68-0.75) for men and 0.87 (0.83-0.91) for women, per 100,000 per year. The equivalent rates for Scotland, based on 639 registrations, were 1.17 (0.91-1.44) for men and 1.36 (1.09-1.63) for women. There was a consistent female excess of carcinoid tumours in the reproductive years, which was reversed after the age of 50. The female excess was most striking for gastrointestinal carcinoid tumours in women aged 15-19 years (F:M ratio = 2.14). The sex differences are probably due in part to incidental diagnosis of carcinoid tumours during abdominal procedures, which are more common in women than men at ages 15-49 years. However, there is some evidence to suggest a true sex difference in incidence, particularly the fact that the sex ratio for thoracic tumours varies with age in a similar way to that for gastrointestinal tumours. Hormonal factors may, therefore, be important in the aetiology of carcinoid tumours.     

Extracorporeal heparin adsorption following cardiopulmonary bypass with a heparin removal device--an alternative to protamine

OBJECTIVES: To evaluate the therapeutic efficacy and applicability of a heparin removal device (HRD) based on plasma separation and poly-L-lysine (PLL) affinity adsorption as an alternative to protamine in reversing systemic heparinization following cardiopulmonary bypass (CPB). DESIGN: A prospective study. SETTING: University research laboratory. SUBJECTS: Adult female swine (n=7). INTERVENTIONS: Female Yorkshire swine (n=7, 67.3+/-3.5 [SEM] kg) were subjected to 60 mins of right atrium-to-aortic, hypothermic (28 degrees C) CPB. After weaning from CPB, the right atrium was recannulated with a two-stage, dual-lumen cannula which was connected to an HRD via extracorporeal circulation. Blood flow was drained at 1431.2+/-25.4 mL/min from the inferior vena cava, through the plasma separation chamber of the HRD (where heparin was bound to PLL), and reinfused into the right atrium. The HRD run time was determined by a previously established mathematical model of first-order exponential depletion. MEASUREMENTS AND MAIN RESULTS: Heart rate, mean arterial pressure, pulmonary arterial pressure, central venous pressure, kaolin and celite activated clotting time (ACT), activated partial thromboplastin time (APTT), heparin concentration, and plasma free hemoglobin were obtained before, during, and after the use of the HRD. Pre-CPB ACT was 167+/-89 secs (kaolin) and 99+/-7 secs (celite), and APTT was 34+/-5 secs. The HRD run time averaged 27.4 +/-1.5 mins targeted to remove 90% total body heparin. Use of the HRD was not associated with any adverse hemodynamic reactions or increases in plasma free hemoglobin. The heparin concentration immediately following CPB was 4.85+/-0.24 units/mL, with ACT >1000 secs and APTT >150 secs in all animals. During heparin removal, total body heparin content followed first-order exponential depletion kinetics. At the end of the HRD run, heparin concentration decreased to 0.51+/-0.09 units/mL, with kaolin ACT returning to 177+/-22 secs, celite ACT returning to 179+/-17 secs, and APTT returning to 27+/-3 secs (p > .05 vs. pre-CPB baseline for all variables). CONCLUSIONS: The HRD is capable of reversal of anticoagulation following CPB without significant blood cell damage or changes in hemodynamics. The HRD, therefore, can serve as an alternative to achieve heparin clearance in clinical situations where use of protamine may be contraindicated.     

Selection of patients with critical limb ischaemia for femorodistal vein bypass

Striatal neurons from E15 rat embryos were dissociated, plated at low cell density on polyornithine or on astrocyte monolayers derived from the striatum (homotopic) or mesencephalon (heterotopic), and cultured in a chemically defined medium. After 2 to 10 days neurons could be divided in 3 classes according to their cell body diameter: small, medium or large. The percentage of small neurons which was very high 60% for GABAergic neurons on polyornithine after 2 days in vitro was reduced to 35% on mesencephalic astrocytes and to less than 20% on striatal astrocytes. The decrease in the number of small cells was paralleled by an increase in the number of multipolar medium size cells whereas the percentages of bipolar medium size and large neurons remained constant (55 and 4% respectively). All results obtained with the general neuronal population were replicated with the GABAergic sub-population which accounted for more than 50% of total neuronal population. These experiments confirm the beneficial influence of homotopic astrocytes on neuronal differentiation and on dendrite growth.     

Arthroscopic anterior cruciate ligament reconstruction using autogenous hamstring tendon graft without detachment of the tibial insertion

This article describes a modified arthroscopic technique of anterior cruciate ligament reconstruction using quadrupled hamstring tendon graft. The autogenous semitendinosus and gracilis grafts are harvested without detachment of the tibial insertion. To obtain longer grafts, the accessory tibial insertions of the hamstring tendons are dissected. The EndoButton (Acufex Microsurgical, Andover, MA) is used for femoral fixation and two spiked staples are used for tibial fixation in a belt buckle fashion. Then the residual anterior laxity is restored by additional absorbable interference screw fixations. In this technique, more viable graft is obtained and more firm distal fixation is achieved by preservation of the tibial insertion of hamstring tendons.     

Coronary bypass surgery using the radial artery. An alternative in patients with varicose veins

Arterial revascularization of the heart with the radial artery was performed in twenty patients with varicosities of the lower legs. The patients all had a good functional result and were free of angina pectoris after the operation. None of the patients had complications from harvest of the radial artery. The patients were mobilized early, as no veins had been harvested from the legs.     

The island posterior calf fasciocutaneous flap: an alternative to the gastrocnemius muscle for cover of knee and tibial defects

By repeatedly presenting an alien scent to territory-owning beavers, Castor canadensis, we tested two competing hypotheses about the function of scent marking: scent fence and scent matching. The scent-fence hypothesis predicts that territory owners should respond increasingly strongly over time towards a recurrent alien scent because of the ineffectiveness of previous responses. The scent-matching hypothesis predicts that the intensity of response should be the same or decrease because, without the presence of the intruding signaller coupled with the chemical signal, the presence of the scent itself does not advertise the ownership of a territory. The response level of resident beaver families was stable to strangers' anal gland secretions (AGSs) and decreased to strangers' castoreum during a period of 6 days. These results support the scent-matching hypothesis but not the scent-fence hypothesis. Copyright 1998 The Association for the Study of Animal Behaviour. Copyright 1998 The Association for the Study of Animal Behaviour.     

Potential advantages of treatment of transplanted saphenous vein aorto-coronary artery bypass grafts with beta irradiation to prevent graft occlusion

Intimal proliferation or Neointimal hyperplasia (NIH) is a vascular lesion that often arises in arteries after balloon angioplasty or other vessel wall injuries. FIH is a vascular lesion that develops in autologous saphenous vein grafts (SVG) after transplantation into the aorto-coronary circulation or the peripheral vascular circulation. FIH shares elements of smooth muscle migration, proliferation and fibrous tissue deposition in common with nibrointimal proliferation (NIH). Either NIH of a coronary artery or FIH of a SVG obstruct the vascular lumen and result in myocardial dysfunction. Local radiotherapy has been used for several decades to reduce the post-operative recurrence of the fibrovascular proliferations of pterygia and keloids. Similarly, in animal and human experiments, endovascular radiotherapy has been shown to reduce arterial smooth muscle proliferation. Consideration of the similarities of vascular smooth muscle cell proliferation in NIH and FIH leads one to suggest that endovascular beta irradiation can reduce FIH as well as it reduces NIH. The goal of such treatment is to achieve a clinically significant decrease in the morbidity and mortality resulting from SVG occlusions. The potential for large reduction of the consequences of SVG occlusion, the very large number of patients at risk, and the simplicity of the proposed intervention encourages prompt scientific evaluation of this technique.     

In situ autogenous reconstruction of the thoracoabdominal aorta and branches for treatment of an infected thoracoabdominal aortobifemoral bypass graft

Graft infection is an uncommon but potentially lethal complication of prosthetic aortic repair. We describe a novel technique for upper abdominal aortic and visceral revascularization after percutaneous drainage and antibiotics failed to cure a thoracofemoral prosthetic graft infection. One week after axillofemoral and femorofemoral bypass grafting, the infected thoracoabdominal graft was removed and a bifurcated iliac artery autograft was used to replace the upper abdominal aorta and revascularize the abdominal viscera. The infected graft was removed from the thorax and retroperitoneum, the infection resolved, and the patient remained well until his death of lung cancer 9 years later.     

Rupture to the skin of atheromatous aneurysm on a femoropopliteal venous bypass using an in situ vein

Atheromatous aneurysmal degeneration of a venous bypass graft is a rare and late event after venous bypass grafting. We report the case of a 49-year-old man in whom a large aneurysm of a saphenous graft implanted 10 years earlier ruptured to the skin. Amputation was required. Graft degeneration can lead to complications which may be life or limb-threatening due to graft rupture, graft thrombosis or distal embolization. Close follow-up after arterial reconstruction using a vein graft is therefore highly warranted for early detection and correction of any abnormalities before onset of complications.     

An emergent coronary artery bypass grafting to total occlusion of all three coronary arteries in a patient with severe hyperbilirubinemia

Totally implanted venous access ports are excellent devices for delivering chemotherapeutic agents and prolonged intravenous infusions in patients with cancer. Catheter fracture and embolization are rare and potentially serious complications of these widely used devices. Retrieval of the embolized fragment is generally indicated but may not be possible. The authors report three cases of catheter embolization in their center over a period of 9 years. Catheter "pinch-off," fracture, embolization, and retrieval are discussed.     

Pharmacological relaxation of the saphenous vein during harvesting for coronary artery bypass grafting

Spasm of the saphenous vein frequently occurs during harvesting from the leg and high-pressure distension is required to restore an adequate diameter for grafting. Forceful distention has been shown to damage the intima and media and may predispose to subsequent occlusion of the vein graft. Various pharmacologic vasodilators are capable of relaxing veins; in this study, we carried out a systematic investigation to determine the appropriate agents and concentrations for use during vein graft operations. In organ baths, human saphenous vein segments were contracted with potassium or a thromboxane mimetic, and vasodilator agents were then applied. Glyceryl trinitrate, 7.2 micrograms/mL, or papaverine hydrochloride, 11.9 micrograms/mL, caused 80% to 100% relaxation of contraction induced by potassium or thromboxane. Verapamil, 15.5 micrograms/mL, relaxed the potassium contraction by 100% and the thromboxane contraction by 75%. Comparison of the time course of action showed that glyceryl trinitrate had a rapid onset and a short duration of maximal action, whereas verapamil (like papaverine) had delayed onset and a long duration. A mixture of glyceryl trinitrate and verapamil combined rapid onset with long duration of action. We now use a mixture of glyceryl trinitrate and verapamil (pH 7.4) topically and intraluminally during harvesting of the saphenous vein to provide a relaxed conduit for coronary artery bypass grafting.     

Results of rapid two-stage arterial switch operation in patients with transposition of the great arteries: one-year postoperation

The rapid two-stage arterial switch operation is an alternative therapy for patients with simple transposition of the great arteries who present beyond the neonatal period and have low left ventricular pressure. It provides normal ventricular function compared to the atrial switch operation. Between July 1994 and February 1997, there were 13 such infants who had rapid two-stage arterial switch operation performed at Siriraj Hospital. There was 1 late death (11 months after the operation). All 12 survivors (mean age 22.4 +/- 5.7 months) were clinically evaluated and had echocardiography performed at 14.8 +/- 4.9 months after the operation. All were asymptomatic. Echocardiogram revealed a residual small atrial septal defect (1 case), small ventricular septal defect (1 case), mild supravalvar neopulmonary stenosis (2 cases), bicuspid neoaortic valve without stenosis (2 cases), dilated neoaortic sinus of Valsalva (6 cases, 50%) and mild neoaortic insufficiency (11 cases, 91.7%). The left ventricular function was hyperdynamic after pulmonary artery banding and significantly decreased to normal level at the time of study (shortening fraction of 43.8 +/- 10.7 vs 29.2 +/- 3.8%, respectively, p = 0.0005). The wall thickness was significantly increased after pulmonary artery banding and decreased overtime (0.48 +/- 0.08 vs 0.32 +/- 0.05 cm, respectively, p < 0.0005). The left ventricular dimension was significantly increased both after pulmonary artery banding and at the time of study (2.06 +/- 0.42 vs 3.32 +/- 0.30 cm, respectively, p < 0.0005). The left ventricular mass was significantly increased after pulmonary artery banding and at the time of study (21.79 +/- 7.79 vs 33.08 +/- 7.40 g/m2, respectively, p = 0.0005). The mortality and morbidity of rapid two-stage arterial switch operation are low. However, long-term follow-up should be monitored.