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Biomedical subjects

M Sobel

Publications and source records attributed to M Sobel.

At least 73 records · Page 4Linked to original sources
PubMed1992

Peroneal tendon subluxation in a case of anomalous peroneus brevis muscle.

We report a case of peroneal tendon subluxation as a result of an anomalous extension of the peroneus brevis muscle into the fibular groove, causing an encroachment phenomenon, stretching-out of the superior peroneal retinaculum, longitudinal splitting of the peroneus brevis tendon, subluxation of the peroneal tendons, and peroneal tenosynovitis. We describe a simple surgical technique for tendon stabilization, after decompression of the fibular groove.

Adult↗
PubMed1991

Arterial-ureteral fistula: case study with review of published reports.

Arterial-ureteral fistula, a rare cause of gross hematuria, may be associated with life-threatening hemorrhage if not rapidly diagnosed and treated. Recently, a patient at the Hunter H. McGuire Veterans Administration Medical Center developed an arterial-ureteral fistula at the site of the confluence of the external iliac artery and a superior mesenteric artery bypass graft. Review of the world's literature revealed 31 additional reported cases of arterial-ureteral fistulas. This current case is only the second one reported in which the diagnosis was made with arteriography. Several common features of arterial-ureteral fistulas were present in this case: a history of ureteral obstruction and urinary tract infections, upper urinary tract disease, and previous vascular surgery. The condition is usually associated with either prior upper urinary tract instrumentation or vascular surgery, and an antecedent period of intermittent hematuria, followed by life-threatening hematuria, is common. A high index of suspicion and early surgical intervention are required for successful management. The major surgical challenges are to establish unobstructed urinary drainage and restore vascular continuity. Exclusion of prosthetic material from potentially infected areas is mandatory.

Fistula↗
PubMed1991

Expression of laminin by human fibroblasts, HT1080 fibrosarcoma cells and MCF-7 breast adenocarcinoma cells. Lack of regulation by the cell density and extracellular matrix.

We have cultured normal fibroblasts, fibrosarcoma HT1080 cells and breast adenocarcinoma MCF-7 cells on various substrates (plastic, collagen type I, laminin). All cell types used adhered on the three substrates with, however, a delayed attachment on laminin. On all substrates, cell grew as monolayer with the exception of MCF-7 cells that formed clusters on laminin. The epithelial MCF-7 cells as well as mesenchymal cells (fibroblasts and tumoral HT1080 cells) synthesized laminin and expressed mRNA coding for laminin B1 chain and for the 67 kD laminin binding protein. The levels of these mRNAs were not modulated by culture conditions which affect cell morphology nor by cell density.

Adenocarcinoma↗
PubMed1991

Assessment of heparin anticoagulation during peripheral angioplasty.

The amount of heparin administered during peripheral angioplasty procedures is controversial and varies greatly among angiographers. Complications may result from both excessive and insufficient anticoagulation. The authors characterized the anticoagulant response to heparin in patients undergoing angioplasty by means of the activated clotting time (ACT). The ACT was measured in 64 patients who underwent lower extremity angioplasty. There was a linear relationship between heparin dose and ACT (P = .0001), but the slope of this relationship varied from patient to patient (R2 = .232). The response to heparin was blunted in one patient with thrombosis, but it was not exaggerated in patients with hematomas. Heparin anticoagulant response is highly variable, and heparin administration should be individualized according to ACT to produce a desired level of anticoagulation. Use of the ACT is a convenient and reproducible means of monitoring heparin administration and may increase safety and efficacy during peripheral angioplasty.

Angioplasty, Balloon↗
PubMed1991

Heparin inhibition of von Willebrand factor-dependent platelet function in vitro and in vivo.

The intravenous administration of heparin to patients before open heart surgery reduced ristocetin cofactor activity by 58% (P less than 0.01, t test), and this impairment of von Willebrand factor-dependent platelet function was closely related to plasma heparin levels (r2 = 0.9), but not to plasma von Willebrand factor (vWF) levels. We hypothesized that heparin may inhibit vWF-dependent platelet hemostatic functions by directly binding vWF in solution and interfering with vWF-GpIb binding. Using the in vitro techniques of ristocetin-induced platelet agglutination, fluorescent flow cytometric measurement of vWF-platelet binding, and conventional radioligand binding assays we observed that heparin inhibited both vWF-dependent platelet function and vWF-platelet binding in a parallel and dose-dependent manner. Heparin also inhibited platelet agglutination induced by bovine vWF and inhibited the binding of human asialo-vWF to platelets in ristocetin-free systems. The inhibitory potency of heparin was not dependent upon its affinity for antithrombin III, but was molecular weight dependent: homogeneous preparations of lower molecular weight were less inhibitory. Heparin impairment of vWF function may explain why some hemorrhagic complications of heparin therapy are not predictable based on techniques for monitoring the conventional anticoagulant effects of heparin.

Agglutination↗
PubMed1991

Cadaver correlation of peroneal tendon changes with magnetic resonance imaging.

Magnetic resonance imaging (MRI) is used to show the soft tissues of the body. The presence of anomalous tendons and muscles can be detected. Chronic lateral ankle pain and instability can be associated with peroneal tendon pathology and MRI may be used to assess both longitudinal attrition of the peroneus brevis tendon, as well as the presence of the peroneus quartus which may be useful in lateral ankle reconstruction. Tenography can occasionally present technical difficulties and can lead to patient dissatisfaction.

Adult↗
PubMed1991

Longitudinal splitting of the peroneus brevis tendon: an anatomic and histologic study of cadaveric material.

Gross and microscopic examinations of 21 split and 10 intact cadaveric peroneus brevis tendons were performed in an effort to determine the pathogenesis of longitudinal splitting of this tendon. The split regions were centered over the posterior margin of the distal fibula and were characterized by splaying of the collagen bundles with accompanying proliferation of blood vessels and fibrovascular connective tissue. Inflammatory infiltrates were not present. Regions of the tendons that were not altered had normal cellularity and orientation of the collagen. The findings of this study suggest that the splitting of the tendon develops through a mechanical mechanism.

Adult↗
PubMed1990

Strategies in the treatment of major tissue loss and gangrene: results of 100 consecutive vascular reconstructions.

To determine the features of a successful clinical strategy, we analyzed the results of 100 consecutive lower extremity vascular reconstructions performed exclusively for tissue loss and gangrene of the legs and feet. Eighty patients underwent 100 procedures on 80 limbs. Follow-up was 95% complete (every six months, mean 2.2 years). Forty inflow procedures to the femoral artery were performed with 13 simultaneous infrainguinal bypasses. Sixty bypasses were performed from the femoral artery to the popliteal (25) or tibial arteries (35). Sixty-eight percent of the identified ulcerations healed, and limb salvage was achieved in 70% of patients by life-table analysis. The cumulative patency for all reconstructions was 48% (five years), for tibial bypasses 60% (four years). Femoropopliteal bypasses had the poorest patency and healing rates (less than 40%), while combined inflow-outflow procedures and femorotibial bypasses had the highest rates of healing (77%, 66%). There were two operative deaths, three graft infections, seven wound infections, and 12 acute graft thromboses. Vascular reconstructions for extensive tissue loss or gangrene can be performed with a morbidity and mortality comparable to procedures performed for less severe disease with a high rate of limb salvage. The long term success of surgical therapy depends primarily on the most direct revascularization of ischemic, infected tissues, using autologous conduits whenever possible.

Aged↗
PubMed1990

Randomized controlled trial of tissue plasminogen activator in proximal deep venous thrombosis.

PURPOSE: To compare the efficacy and safety of recombinant human tissue-type plasminogen activator (rt-PA, supplied as Activase) with heparin alone or rt-PA plus heparin in the treatment of venographically documented proximal deep venous thrombosis (DVT) of the leg. PATIENTS AND METHODS: Sixty-four patients underwent 65 randomizations to rt-PA alone (n = 36), rt-PA plus heparin (n = 17), or heparin alone (n = 12) in a prospective, multicenter, randomized, open-label trial, with efficacy assessed by a radiology panel unaware of treatment assignment. Patients randomly assigned to rt-PA received 0.05 mg/kg/hour for 24 hours via a peripheral vein, with a maximum dose of 150 mg. All patients then received heparin and warfarin for the remainder of the hospitalization. Follow-up venography was performed 24 to 36 hours after initiation of therapy. RESULTS: Complete or more than 50% lysis occurred in 10 (28%) patients treated with rt-PA, five (29%) patients with rt-PA plus heparin, and no patient treated with heparin. No lysis occurred in 16 (44%) patients treated with rt-PA plus heparin, and 10 (83%) patients who received heparin alone (p = 0.04). There was one major complication, a nonfatal intracranial hemorrhage in a patient who received rt-PA alone. At 7 to 10 days after initiation of treatment, the level of serum glutamic oxaloacetic transaminase nearly doubled among all patients, including those assigned to receive heparin alone. CONCLUSION: (1) rt-PA and rt-PA plus heparin cause more clot lysis than heparin alone; (2) the addition of heparin to rt-PA does not improve the lysis rate; (3) DVT treated with heparin is commonly associated with a rise in the transaminase level; (4) heparin does not increase the risk of bleeding from rt-PA therapy; and (5) alternative dosing regimens and modes of administration of rt-PA should be investigated to improve further its efficacy and safety in the treatment of acute DVT.

Adolescent↗
PubMed1990

Metacarpal-phalangeal joint arthroplasty of the rheumatoid thumb.

Fifty patients with rheumatoid arthritis had 59 Swanson implants of the metacarpal-phalangeal joint of the thumb. Eleven patients (15 implants) have since died and only 1 patient (1 implant) has been lost to follow-up leaving 43 implants available for study. The most common preoperative deformity was a boutonniere deformity with a flexible interphalangeal joint. All thumbs had less pain after operation. The average range of active motion is 25 degrees, with a flexion arc from 15 to 40 degrees. There is an average key pinch strength of 4 pounds (range, 0.5 to 10). Improvement in activities of daily living were noted in 40 hands. One thumb required reoperation for instability; the implant was removed and a metacarpal-phalangeal arthrodesis was done. Radiographic progression of disease was noted in only one thumb at the interphalangeal joint and in two other thumbs at the carpometacarpal joint. None of these have required further operations. The maintenance of motion appears to help in activities of daily living as stability and pinch strength are often adequate.

Adult↗
PubMed1990

Trispherical total wrist arthroplasty in rheumatoid arthritis.

Thirty-four patients, with 35 trispherical total wrist arthroplasties for treatment of rheumatoid arthritis, were evaluated at an average follow-up of 9 years (range, 5 to 11 years). The average preoperative score was 25 points inasmuch as all patients had severe pain and loss of function. The average postoperative score improved to 87 points since 30 wrists were free of pain. Twenty-eight wrists rated as a good-to-excellent result. The average arc of flexion and extension improved from 35 to 50 degrees. There were no deep infections or dislocations. Two wrists required revision, one for loosening and one for persistent pain, both requiring removal of the implant and arthrodesis. Postoperative tendon attrition occurred in six wrists, all of which had preoperative tendon ruptures necessitating tendon transfer. Radiographs showed radiolucencies in seven wrists, including seven around the metacarpal stem and one around the radial stem. The optimum results were achieved in those patients with intact extensor tendons before operation.

Adult↗
PubMed1990

The results of treatment of supracondylar fracture above total knee arthroplasty.

This study analyzes the results of treatment of 22 patients with 24 supracondylar femur fractures above a total knee arthroplasty. Ten knees were treated by closed methods utilizing traction and then a cast, 10 knees with immediate open reduction and internal fixation, 2 knees with a custom total knee integrated with a distal femoral allograft, 1 knee with external fixation, and 1 knee with primary arthrodesis. Nine fractures treated by closed means and 5 fractures treated by open reduction and internal fixation healed primarily. Two of the 5 surgical failures healed after replating and bone graft. The 3 failures of surgical therapy were salvaged utilizing custom total knee arthroplasty, 2 of which required integration with a distal femoral allograft. One knee treated with external fixation developed a deep infection necessitating implant removal and arthrodesis. Twelve of the 14 femoral fractures that united primarily healed with the femoral component in varus with respect to the long axis of the anatomic femur. Nine of these 12 implants developed progressive radiolucent lines at the tibial component. Three of these knees have required implant revision due to progressive loosening of the tibial and/or femoral components. The results of this evaluation indicate that fractures above a well-fixed total knee arthroplasty are difficult to manage. If anatomical alignment cannot be achieved by simple closed techniques, then primary open reduction and internal fixation should be considered. However, because of the complexity of the problem, the surgeon should be prepared to perform a primary arthrodesis or revision using custom components with or without a distal femoral allograft.

Adult↗
PubMed1990

Congenital variations of the peroneus quartus muscle: an anatomic study.

There has been little research concerning this muscle since the 1920s, when Hecker described this muscle to be present in (13%) of his dissections of cadaver legs. The purpose of our dissections was to establish the incidence of the peroneus quartus muscle, its origins, and insertions. One hundred and twenty-four legs from 65 fresh human cadavers were dissected under loupe magnification. When the peroneus quartus tendon was found, its origin, insertion, and anatomic relationship to the peroneus longus and peroneus brevis were observed. All specimens were sketched and photographed. The peroneus quartus muscle was present in 27 legs (21.7% of specimens). Its origins, insertions, and size varied. In 17 legs (63%) the muscle originated from the muscular portion of the peroneus brevis, and inserted on the peroneal tubercle of the calcaneus. The peroneal tubercle was hypertrophied at the insertion in most cases. The results of this study in general show that there was much higher incidence of the peroneus quartus muscle than Hecker claimed. Its course, origin, and insertion varied. Its tendon can be used for reconstructive procedures about the lateral aspect of the ankle, especially in anterior dislocation of the peroneal tendons and reconstruction of lateral ligaments.

Aged↗
PubMed1990

Longitudinal attrition of the peroneus brevis tendon in the fibular groove: an anatomic study.

There has been little research concerning the attrition of the peroneus brevis tendon since Meyer's observation in 1924. The purpose of our dissections was to establish the incidence of the attrition of the peroneus brevis tendon at the fibular groove, and observe the anatomical relationship of the tendon attrition to the bony anatomy of the distal fibula. One hundred and twenty-four fresh human cadavers ankles from 65 cadavers were dissected under loupe magnification. When attrition of the peroneus brevis was found, the extent of attrition was measured, and anatomic proximity of the tendon to distal fibular groove was observed. Evidence of other tendon attrition as well as the depth of the fibular groove was observed. Specimens which revealed attrition of the peroneus brevis were sketched and photographed. Attrition of the peroneus brevis tendon was found in 14 ankles (11.3% of specimens). The attrition was limited only to the peroneus brevis tendon, and in no specimens was the peroneus longus involved. The degree of tendon attrition varied from simple splaying out of the peroneus brevis in the fibular groove to longitudinal splits in the peroneus brevis tendon with significant fraying of the remaining halves of the tendon. The longitudinal ruptures in the peroneus brevis tendon averaged 1.9 cm (range 1-4 cm). In all cases, the central portion of the longitudinal split was centered over the distal tip of the fibula in the fibular groove. In no case was a complete rupture of the peroneus brevis tendon noted. There was gross evidence of chronic inflammation and synovitis in those ankles with attrition of the peroneus brevis tendon.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗