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Biomedical subjects

C T Lu

Publications and source records attributed to C T Lu.

At least 37 records · Page 2Linked to original sources
PubMed1988

Indications, surgical technique, and long-term functional results of colon interposition or bypass.

Over a 17-year period, 92 patients with esophageal disease underwent colon interposition or bypass, with each operation performed by the same surgeon. The indication was cure of cancer in 20 patients, relief of dysphagia in 55 (cancer in 17 patients and benign in 38), loss of gastrointestinal (G.I.) continuity in ten, and tracheoesophageal fistula in seven patients (malignant in five, benign in 2). The thirty-day operative mortality rate was 5%, and the hospital mortality rate was 9%. Graft necrosis occurred in seven of 92 patients, four of whom later underwent a successful second reconstruction. Thirteen patients required subsequent revisional surgery. In 85 patients, the left colon based on the inferior mesenteric artery was used, and in seven, the right colon was used. Technical insights were gained to help preserve the blood supply to the graft and improve its function in transporting food. Thirty-four patients were available for interview 2-17 years after operation (median of 5 years) 28 of whom had benign disease, and six of whom had malignant disease); 82% of the patients felt they were cured of their preoperative symptoms, 18% improved, and none worsened. Eighty-eight per cent of the patients were able to receive an unrestricted diet. All patients except one were satisfied with the results of surgery, and, asked what they would do if they had to make the choice again, all responded that they would have the operation. Twenty-six of the interviewed patients had their eating ability evaluated with a test meal and the transit time of a liquid and solid barium bolus measured. Compared to controls, patients with colon interpositions consumed a smaller capacity meal over a longer period of time and were not dependent on liquids to flush the food through the colon graft. A colon interposition provides good quality of deglutition, is very durable, and is the organ of choice for patients who require an esophageal substitute and are potential candidates for long survival.

Adult↗
PubMed1986

Increased collagenase activity in early aneurysmal dilatation.

Increased collagenase activity has been implicated as a basic abnormality in aortic aneurysm formation. We studied a localized aneurysmal change, poststenotic dilatation, and its relation to collagenase and elastase activity of the aortic wall. Cynomolgus monkeys underwent midthoracic aortic coarctation to produce poststenotic dilatation. Serial angiography showed that poststenotic dilatation was minimal or absent at 10 days, just discernible at 3 months, and prominent at 6 months. At the 3-month time interval, collagenase activity in the region of the poststenotic dilatation increased twofold compared with the same region in aortas from animals without poststenotic dilatation (p less than 0.05). There was no change in aortic elastase activity. These data indicate that collagenolysis and aneurysmal dilatation may be induced by local modifications of pressure and/or flow. Increased collagenase activity associated with abdominal aortic aneurysms may not represent an intrinsic metabolic defect but rather a response to altered hemodynamic conditions.

Animals↗
PubMed1986

New criteria for placement of a prophylactic vena cava filter.

In order to identify patients who, having had an initial pulmonary embolism, are likely to develop recurrent emboli despite adequate anticoagulation therapy, ten patients (group 1) with documented recurrent pulmonary embolism during anticoagulation therapy were compared with 31 patients (group 2) who showed no evidence of recurrent emboli during the treatment period. Risk factors for thromboembolic disease were similar between the two groups. Noninvasive venous studies of the lower extremities, including Doppler venous ultrasound and phleborheography (PRG), were performed upon all patients after the initial embolic event. Of the ten patients in group 1, seven (70 per cent) had clinical signs of deep vein thrombosis (DVT). Doppler studies were positive for eight of the nine patients studied, and PRG studies were positive for eight of eight patients tested. In contrast, of the 31 patients who responded well to medical therapy, one patient (3 per cent) had clinical signs of DVT, three patients (10 per cent) had positive Doppler studies and one patient (3 per cent) had a positive PRG. Combined Doppler and PRG studies were positive in 100 per cent of the patients in group 1 but in only 6 per cent of the patients in group 2 (p less than 0.001). The results of this study suggest that patients having an initial pulmonary embolism and DVT of sufficient extent detected by noninvasive studies may be at an increased risk for recurrent PE despite anticoagulation therapy. Insertion of a vena cava filter should be considered in these patients prior to the second embolic event.

Adult↗
PubMed1983

Limb salvage in poor-risk patients using transluminal angioplasty.

We performed percutaneous transluminal angioplasty (PTA) in 97 limbs of 86 patients with end-stage occlusive disease in whom vascular reconstruction was not possible. Most patients required dilation of long-segment occlusions and/or multiple lesions. Angiographic appearance was improved in 87 limbs of 78 patients (90%). Ankle-brachial pressure index increased from 0.40 +/- 0.03 to 0.64 +/- 0.03, and increased more than 0.15 in 63% of the limbs. Major amputation was required in 19 of the 87 limbs (22%) following PTA. The incidence of restenosis was 19% at three months, 42% at six months, and 57% at one year. Repeated PTA successfully maintained vascular patency in ten limbs, and four patients have since had successful distal bypass. Two limbs that initially improved needed amputation four to 19 months after dilatation. Follow-up ranged from one to 45 months; overall limb salvage rate was 76%. Thus PTA can enhance limb salvage in poor-risk patients with end-stage disease.

Adult↗
PubMed1983

Selective infusion of streptokinase for arterial thrombosis.

We have treated 13 patients with limb-threatening ischemia caused by acute arterial thrombosis with selective arterial infusion of streptokinase. The indications for thrombolytic therapy included medical contraindication to surgery, surgically inaccessible thrombi, arterial thrombosis following percutaneous transluminal angioplasty, and thrombosed distal arterial bypass. Patients were evaluated with arteriography, Doppler segmental arterial pressure studies, and coagulation profile. Objective evidence of complete or partial thrombolysis was demonstrated in 11 of the 13 patients (85%). Treatment after thrombolytic therapy included percutaneous transluminal angioplasty in six patients and distal bypass in two patients. Of five patients who had received no additional treatment, three required amputation. Overall limb salvage was achieved in 10 of the 13 patients. The most serious complications were puncture site bleeding in five patients, acute renal failure in one patient, and retroperitoneal hemorrhage in another patient. Bleeding was more frequent in patients with decreased serum fibrinogen levels. Although lysis of acute arterial thrombi can be achieved, thrombolytic therapy alone will allow limb salvage in only a few patients. Selective thrombolytic therapy with streptokinase must be used with caution and is associated with serious complications.

Aged↗
PubMed1982

Percutaneous transluminal angioplasty for limb salvage.

Thirty patients with end-stage atherosclerosis, being considered for amputation, were treated by percutaneous transluminal angioplasty (PTA). All had very poor run-off, and none was a candidate for arterial reconstruction. Occluded segments of the iliac, femoral, popliteal, and tibial arteries measuring up to 21 cm were recanalized, resulting in an increased ankle/brachial systolic pressure index despite significant distal occlusive disease. Ischemic symptoms were relieved in 22 patients, and the overall limb salvage rate (2- to 17-month follow-up) was 73%.

Aged↗
PubMed1982

Long-segment arterial occlusion: percutaneous transluminal angioplasty.

In cases of occlusion of the superficial femoral artery exceeding a length of 10 cm, accompanied by involvement of the popliteal artery and poor runoff, percutaneous transluminal angioplasty is unfavorable. However, when such advanced occlusive disease is present in patients for whom vascular surgery is not feasible, this technique can be of value by averting or at least postponing amputation. Percutaneous transluminal angioplasty was used to recanalize long segments (10-36 cm) of occluded or stenotic femoropopliteal arteries in 21 patients. Results were evaluated by means of pre- and postangioplasty arteriograms and measurements of pressure indices. The initial success rate was 76%; the success rate on 5-24 month follow-up was 67%. The long-term benefit can be improved by other measures, such as stopping cigarette smoking, exercise, long-term anticoagulation therapy, and early detection and treatment of restenosis.

Aged↗
PubMed1982

Arterial disruption and remodeling following balloon dilatation.

We studied immediate and long-term alterations in human atherosclerotic arteries subjected to balloon dilatation. Pathologic material included vessels obtained at amputation or autopsy that had been previously dilated in vivo and cadaver vessels dilated under physiologic pressure and temperature. All vessels were pressure-perfusion fixed, and morphologic observations were correlated with sequential angiograms obtained in 36 patients. Balloon dilatation resulted in disruption of both the plaque and the artery wall, with separation of the plaque from the tunica media, rupture of the tunica media, and stretching of the tunica adventitia to increase lumen cross-sectional area. The intimal plaque protruded into the lumen, accounting for the angiographic appearance of local flaps and dissection channels. Remodeling occurred by readherence of the intimal flaps with little change in plaque volume. Achievement of a sufficient radius of curvature may be necessary to achieve long-term patency. Restenosis may occur because of insufficient dilatation but may also result from extention of dissection channels into nondilated segments of the artery.

Angiography↗
PubMed1981

Crystal structure and conformation of cyclo-L-cystine.

X-ray crystallographic investigations on cyclo-L-cystine show that the diketopiperazine ring is in a twisted boat form and the C-S-S-C bridge across the C alpha atoms has a negative chirality with chi 3 angle of - 94 degrees, The two peptides are significantly nonplanar with the omega values of - 10 degrees and - 16 degrees. The crystals are orthorhombic, space group P212121 with a = 11.216(4), b = 12.874(4), c = 5.978(3) and Z = 4. The structure was solved by heavy atom method and refined to an R index of 0.065.

Cystine↗
PubMed1980

Limb salvage by percutaneous transluminal recanalization of the occluded superficial femoral artery.

Six patients with rest pain and gangrene or ulceration were treated by percutaneous transluminal angioplasty using the Grüntzig balloon catheter. All had superficial femoral artery occlusion with severe stenosis or occlusion of the popliteal and tibial arteries. Two patients had previous distal bypass procedures which had failed, and none was a candidate for arterial reconstruction. The superficial femoral artery was recanalized in five patients with an increase in the above-knee pressure index from 0.5 +/- 0.1 to 1.0 +/- 0.1 (P less than 0.001) and ankle pressure index from 0.2 +/- 0.1 to 0.5 +/- 0.1 (P less than 0.001). All five patients avoided early amputation and were able to ambulate when discharged. The sixth patient could not be recanalized and required above-knee amputation. Restenosis of the recanalized superficial femoral artery occurred in four patients 2 to 5 months later, and repeat transluminal angioplasty was successful in three patients. Two patients have required below-knee amputation 4 and 5 months after recanalization. Transluminal angioplasty can extend our capability of early limb salvage.

Aged↗