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Biomedical subjects

J Bonn

Publications and source records attributed to J Bonn.

At least 37 records · Page 2Linked to original sources
PubMed1993

Measles control in developing and developed countries: the case for a two-dose policy.

Despite major reductions in the incidence of measles and its complications, measles control with a single dose of the currently used. Schwarz strain vaccine has failed to eradicate the disease in the developed countries. In developing countries an enormous toll of measles deaths and disability continues, despite considerable efforts and increasing immunization coverage. Empirical evidence from a number of countries suggests that a two-dose measles vaccination programme, by improving individual protection and heard immunity can make a major contribution to measles control and elimination of local circulation of the disease. Cost-benefit analysis also supports the two-dose schedule in terms of savings in health costs, and total costs to society. A two-dose measles vaccination programme is therefore an essential component of preventive health care in developing, as well as developed countries for the 1990s.

Cost-Benefit Analysis↗
PubMed1992

Intraarterial chemotherapy with limb-sparing resection of large soft-tissue sarcomas of the extremities.

Fifteen patients with large (average, 15-cm), high-grade soft-tissue sarcomas of the extremities received prolonged selective intraarterial infusions of chemotherapeutic agents in an attempt to permit limb-sparing resection of these tumors, which would otherwise have required amputation. There were seven malignant fibrous histiocytomas, four liposarcomas, two fibrosarcomas, one leiomyosarcoma, and one rhabdomyosarcoma; 73% were grade III. Seven patients underwent two catheterizations, for a total of 22 infusions, which averaged 11.3 days each. There were four catheterization-related complications, including catheter occlusion or dislodgement in one patient each and two cases of arterial thromboembolism in patients in whom anticoagulant dose was not adequate. Both of the latter patients required thrombectomy; one developed gangrene, which precluded limb-sparing surgery. Thirteen of the 15 patients underwent limb-sparing resections, and two underwent amputations. No wound complications occurred. With a median follow-up of 36 months (mean, 34 months), life-table analysis indicates overall and disease-free survivals of 72% and 59%, respectively, at 2 years and 64% and 59% at 3 years. In comparison to other reported therapies, this technique permits limb salvage in most patients without the high wound complication rate associated with preoperative radiation therapy, with equivalent local disease control and survival.

Adult↗
PubMed1991

Recanalization of an occluded aortoiliac bypass graft with Palmaz stents.

Four tandem Palmaz balloon-expandable vascular stents were used to recanalize the completely occluded limb of an aortoiliac bypass graft after failure of thrombolysis and conventional angioplasty. The resting peak-systolic pressure gradient across the occluded limb was reduced from 68 to 13 mm Hg. The patient's rest pain resolved, and the ankle-brachial index rose from 0.54 to 0.78. No embolization or stent-related complications occurred. The graft remains patent as determined with noninvasive studies obtained 8 months later.

Anastomosis, Surgical↗
PubMed1991

Transhepatic laser lithotripsy of choledocholithiasis: initial clinical experience.

Three patients with symptomatic intra- and extrahepatic choledocholithiasis who were not good candidates for retrograde endoscopy, surgery, or extracorporeal shock wave lithotripsy (ESWL) were treated successfully with endoscopically guided tunable dye laser lithotripsy via a 12-F transhepatic sheath. There were no complications secondary to the use of the laser. On the basis of this initial experience, transhepatic laser lithotripsy is a technically feasible and safe alternative when choledocholithiasis cannot be managed with retrograde endoscopy, ESWL, or surgery. Its role in the management of choledocholithiasis relative to other transhepatic techniques remains to be determined.

Adult↗
PubMed1991

Results of a multicenter study of the modified hook-titanium Greenfield filter.

Initial efforts to modify the stainless steel Greenfield filter for percutaneous insertion led to development of a titanium Greenfield filter, which could be inserted by use of a 12F carrier. This device functioned well as a filter but had an unacceptable 30% rate of migration, tilting, and penetration. Therefore a titanium Greenfield filter with modified hooks was developed and has been tested in 186 patients at 10 institutions. Successful placement occurred in 181 (97%); placement of the remainder was precluded by unfavorable anatomy. A contraindication to anticoagulation was the most frequent indication for insertion (75%). All but two were inserted percutaneously, predominantly via the right femoral vein (70%). Initial incomplete opening was seen in four patients (2%), which was corrected by guide wire manipulation and asymmetry of the legs in 10 (5.4%). Insertion site hematoma occurred in one patient, and apical penetration of the cava during insertion occurred in a second patient. Both events were without sequelae. Follow-up examinations were performed at 30 days at which time 35 deaths had occurred. Recurrent embolism was suspected in six patients (3%) and two of three deaths were confirmed by autopsy. Filter movement greater than 9 mm was seen in 13 patients, (11%) and increase in base diameter greater than or equal to 5 mm was seen in 17 patients (14%). CT scanning showed evidence of caval penetration in only one patient (0.8%). Insertion site venous thrombosis was seen in 4/46 (8.7%) patients screened. The modified hook titanium Greenfield filter is inserted percutaneously or operatively through a sheath, eliminating concern for misplacement from premature discharge.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

Efficacy of thrombolysis in infrainguinal bypass grafts.

The initial outcome of a consecutive series of 43 intra-arterial urokinase infusions for thrombosed infrainguinal grafts in 37 patients was analyzed. There was an 88% (38/43) technical success rate (complete clot lysis) and a 74% (32/43) clinical success rate. Complications occurred in 10 patients (23%) and were related to bleeding in four patients (9%). Patient age, graft age, location, material, and the duration of occlusion did not significantly influence the initial outcome, although there was a trend toward a higher bleeding complication rate among grafts less than or equal to 1 month of age at the time of thrombolysis. A second group of 43 infrainguinal grafts successfully recanalized using regional infusions of thrombolytic agents were followed for long-term patency. This group included 32 grafts successfully treated with urokinase and 11 grafts recanalized with streptokinase. By life-table analysis there was a 55.6% 1-year patency, which fell to 42.4% at 4 years. Vein grafts had significantly (p = 0.01) better long-term patency than prosthetic grafts (69.3% versus 28.6% at 30 months). Grafts with flow-limiting lesions identified and corrected by angioplasty or surgery also had significantly (p = 0.01) better long-term patency than those without such lesions (79.0% versus 9.8% at 2 years). Based on the results of our study compared with a survey of long-term results following secondary surgical procedures for thrombosed infrainguinal grafts, thrombolysis can be recommended in several circumstances. Thrombolysis is indicated for thrombosed vein grafts or when thrombus is present in distal runoff vessels. Thrombosed prosthetic grafts should be replaced by autogenous vein grafts whenever possible.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1990

Palmaz vascular stent: initial clinical experience.

The safety and efficacy of the Palmaz balloon-expandable vascular stent and its effect on the results of percutaneous transluminal angioplasty (PTA) were assessed in a prospective study. Technical success was achieved in the placement of 34 of 35 stents (97%) in 27 common and external iliac artery lesions in 19 patients (23 limbs) who presented with disabling claudication, rest pain, or gangrene. Stent placement improved the angiographic results achieved by PTA alone in all 19 patients. Seventeen of 23 limbs (74%) had significant (greater than 20%) elevation of the ankle-arm index after combined angioplasty and stent placement, including nine limbs with occlusive outflow lesions. All 10 patients with continuous runoff distal to the stent and one patient with discontinuous runoff had resolution of their symptoms, remaining unchanged at a mean follow-up time of 6 months. There were three complications: One significantly altered the patient's hospital course, but none detracted from the achieved stent result. Stent placement is effective and does not significantly increase the complication rate of conventional iliac PTA. The current delivery system, however, may limit its utility.

Angioplasty, Balloon↗
PubMed1990

Extremity osteosarcomas: intraarterial chemotherapy and limb-sparing resection with 2-year follow-up.

Twenty-eight consecutive patients with extremity osteosarcoma (24 stage II, four stage III) received their entire preoperative course of chemotherapy intraarterially in order to maximize local drug concentration and tumor shrinkage to facilitate limb-sparing resection. Eighteen tumors were located in the femur, seven in the tibia, two in the humerus, and one in the fibula. Most patients underwent two catheterizations; thus there was a total of 51 procedures. The average duration of each infusion was 10.4 days. There were eight procedure-related complications, but none precluded completion of intraarterial chemotherapy. Limb-sparing surgery was performed on 25 patients. At a mean follow-up of over 2 years, there was one local recurrence. Among limb-salvage patients with stage II disease, 90% (18 of 20) survived and 75% (15 of 20) are disease-free. Compared with patients from previous studies, this technique permits a high percentage of patients with osteosarcoma to undergo limb-sparing resection without compromise of local disease control or survival.

Adolescent↗
PubMed1990

Selective arterial stimulation of secretin in localization of gastrinomas.

In two patients with malignant gastrinoma and the Zollinger-Ellison syndrome, we were able to use selective arterial stimulation with secretin as a technique to localize the lesions accurately, allowing resection. The technique of selected arterial secretin stimulation is one of measuring variations in gastrin levels in both the hepatic vein and a peripheral artery at specified times after injection of secretin into a specific artery. When the criteria for localization have been met, one can plot the presence of the gastrinoma within the blood supply of the injected artery and, using angiograms, thus accurately localize the lesion. This method promises to be a valuable additional tumor-localizing procedure, particularly when gastrinomas are extrapancreatic.

Adenoma, Islet Cell↗
PubMed1989

Acceleration of thrombolysis with a high-dose transthrombus bolus technique.

The rate of complication and the time necessary to achieve thrombolysis remain major disadvantages of regional thrombolytic therapy. By lacing the entire length of arterial or arterial bypass graft occlusions in the lower extremities of 49 patients with one of two different bolus doses of urokinase (mean, 52,000 International U in 35 infusions = low-dose group [28 patients]; mean, 230,000 U in 23 infusions = high-dose group [21 patients]) prior to identical continuous infusions, it was possible to demonstrate a decrease in the time needed to complete thrombolysis from 33.6 hours in the low-dose group to 10.4 hours in the high-dose group (P less than .001). The total urokinase dose necessary for successful thrombolysis was also significantly less in the high-dose group (P less than .001). The major complication rate was 22.9% in the low-dose group and 8.7% in the high-dose group, although the difference was not statistically significant. The use of urokinase and a high-dose transthrombus bolus injection technique significantly accelerates thrombolysis, decreases the total urokinase dose needed, and may lower the major complication rate.

Aged↗
PubMedDate not supplied

Placenta accreta: comparison of cases managed with and without pelvic artery balloon catheters.

OBJECTIVE: To describe our experience with the use of prophylactic pelvic artery balloon catheters in cases of placenta accreta diagnosed by antenatal ultrasound and to compare these cases with contemporary controls. METHODS: In this prospective study, all patients seen at our institution between January 1994 and August 1997 with the antenatal sonographic diagnosis of placenta accreta were offered prophylactic preoperative pelvic artery balloon catheterization. Patients who were delivered by cesarean hysterectomy for unsuspected placenta accreta in our institution during the same time interval served as controls. Five patients with the sonographic diagnosis of placenta accreta underwent prophylactic pelvic artery balloon catheterization. Surgical outcomes in patients who received balloon catheters were compared with those managed without them. Statistical analysis was performed using the Mann-Whitney U test. RESULTS: Five patients with placenta accreta or one of its variants were correctly identified with antenatal ultrasonography. Of the five patients who underwent pelvic artery balloon catheterization, all had placenta accreta and four required cesarean hysterectomy. The mean estimated blood loss, transfusion requirement, and length of hospitalization in patients undergoing hysterectomy managed with and without the balloon catheters was not different (P > 0.06). CONCLUSIONS: Antenatal sonographic diagnosis of placenta accreta enables preoperative planning. In our experience, use of pelvic artery balloon occlusion catheters in patients requiring a cesarean hysterectomy for placenta accreta did not improve surgical outcomes compared with patients managed without them. These preliminary findings are based on a small number of patients; therefore, further investigation is needed.

Adult↗
PubMedDate not supplied

Venography with carbon dioxide as a contrast agent.

PURPOSE: The purpose of this study was to evaluate the feasibility, safety, and potential role of carbon dioxide (CO2) as a contrast agent for venography. METHODS: Consecutive patients with contraindications to iodinated contrast agents or with unsatisfactory iodinated contrast studies underwent CO2 digital subtraction venography. The images were rated by three experienced angiographers. Image quality and complications were assessed. RESULTS: Over a 14-month period, 66 vein segments were studied in 21 patients. There was good correlation between experienced angiographers on CO2 image quality (Ri = 0.80) and good agreement on diagnosis (k = 0.62). In 91% of the vein segments evaluated with C02 there was interobserver agreement on the diagnosis. Upper extremity veins were adequately imaged with CO2 alone in all (6/6) patients with contraindications to iodinated contrast. Following suboptimal iodinated contrast studies in six patients, CO2 produced significantly better quality upper extremity central vein images (p < 0.05). Pain following injection into peripheral veins was the only CO2-related complication. Inferior vena cava (IVC) filters were successfully deployed with CO2 alone in 78% (7/9) of patients; two required iodinated contrast. CONCLUSIONS: Based upon initial experience, CO2 venography can be recommended in patients with contraindications to iodinated contrast or unsatisfactory iodinated contrast studies.

Adult↗