Roles of Dopaminergic D1 and D2 Receptors in Catecholamine Release from the Rat Adrenal Medulla

The aim of the present study was designed to establish comparatively the inhibitory effects of D1-like and D2-like dopaminergic receptor agonists, SKF81297 and R(-)-TNPA on the release of catecholamines (CA) evoked by cholinergic stimulation and membrane depolarization from the isolated perfused model of the rat adrenal medulla. SKF81297 (30 micrometer) and R-(-)-TNPA (30 micrometer) perfused into an adrenal vein for 60 min, produced great inhibition in the CA secretory responses evoked by ACh (5.32x10(-3) M), DMPP (10(-4) M), McN-A-343 (10(-4) M), high K+ (5.6x10(-2) M), Bay-K-8644 (10 micrometer), and cyclopiazonic acid (10 micrometer), respectively. For the release of CA evoked by ACh, high K+, DMPP, McN-A-343, Bay-K-8644 and cyclopiazonic acid, the following rank order of inhibitory potency was obtained: SKF81297>R-(-)-TNPA. However, R(+)-SCH23390, a selectve D1-like dopaminergic receptor antagonist, and S(-)-raclopride, a selectve D2-like dopaminergic receptor antagonist, enhanced the CA secretory responses evoked by ACh, high K+, DMPP, McN-A-343, Bay-K-8644 and cyclopiazonic acid only for 0~4 min. The rank order for the enhancement of CA release evoked by high K+, McN-A-343 and cyclopiazonic acid was R(+)-SCH23390>S(-)-raclopride. Also, the rank order for ACh, DMPP and Bay-K-8644 was S(-)-raclopride > R(+)-SCH23390. Taken together, these results demonstrate that both SKF81297 and R-(-)-TNPA inhibit the CA release evoked by stimulation of cholinergic (both nicotinic and muscarinic) receptors and the membrane depolarization from the isolated perfused rat adrenal gland without affecting the basal release, respectively, but both R(+)-SCH23390 and S(-)-raclopride facilitate the CA release evoked by them. It seems likely that the inhibitory effects of SKF81297 and R-(-)-TNPA are mediated by the activation of D1-like and D2-like dopaminergic receptors located on the rat adrenomedullary chromaffin cells, respectively, whereas the facilitatory effects of R(+)-SCH23390 and S(-)-raclopride are mediated by the blockade of D1-like and D2-like dopaminergic receptors, respectively: this action is possibly associated with extra- and intracellular calcium mobilization. Based on these results, it is thought that the presence of dopaminergic D1 receptors may play an important role in regulation of the rat adrenomedullary CA secretion, in addition to well-known dopaminergic D2 receptors.

Risk Factors of Dislocation Occurring after Acetabular Component Revision

Purpose: To analyze the causes and to prevent dislocations of the hip joint that occur in patients who underwent revisions of total hip arthroplasties by changing only the polyethylene liners and femoral heads, subsequent to primary total hip arthroplasties. Materials and Methods: We evaluated 28 patients who underwent acetabular component revisions of total hip arthroplasties subsequent to primary total hip arthroplasties. The average age of the patients was 55 years old and all 28 patients had operations through the posterolateral approach. In 17 of the cases, the acetabular cups, polyethylene liners, and femoral heads were changed; in 10 cases, just the polyethylene liners and femoral heads were changed; and in 1 case, only the polyethylene liner was changed. Results: We observed 7 cases of hip dislocations that occurred among a total of 28 cases after revisions of total hip arthroplasties. In all 7 cases, the polyethylene liners and femoral heads were changed, but not the acetabular cups. In additional, in all 7 cases of dislocation, the patients were non-compliant and started weight-bearing prematurely after revisions of the total hip arthroplasties Conclusion: We observed new dislocations in the 7 cases in which the polyethylene liners and femoral heads were changed. The main reasons were inadequate soft tissue tension and hip joint laxity. Therefore, it is necessary to increase the neck length, use elevated rim polyethylene liners, readjust the acetabular cups to their optimal positions, and apply hip abduction braces to patients early after revision of total hip arthroplasties in order to lessen the danger of dislocations.

Disassembly of Polyethylene Liner in Cementless Metal-Backed Cup: A case report / 대한정형외과학회잡지

In 1971, for purpose of reduction of peak stress occuring in cement and trabecular bone of the acetabulum, Harris reported a series of metal-backed acetabular components with removable polyethylene liners that could be replaced if excessive wear occured. Modular designs of hip prostheses have become popular recently, but they introduce the risk of disassembly of the components postoperatively. And introduce of loosening and infection of femoral or acetabular components by debris of polyethylene liner. We report a case of mechanical disassembly of polyethylene liner in cementless metal backed cup, and review previously reported articles.

Lipoma Arborescens of Hip Joint: A Case Report / 대한정형외과학회잡지

Lipoma Arborescens is rarely encountered in hip joint. This term was first used by Mueller in 1838, to describe a fatty trmor of the knee which presented branched villous-like projection. The etiology is unknown, Suggests its probable reationship to tuberculosis, rheumatoid arthitis, trauma, chronic inflammation, diabetes mellitus and degenerative arthritis. It frequently involves knee joint, hand, wrist, foot, ankle, tendon sheath and hip joint. It usually presents bilaterally. Their nonspecific symptoms and signs are mild pain, joint swelling with minimum effusion, festriction of joint motion, redness, local heating and crepitus. We experienced a case of lipoma arborescens of hip joint, which was treated by synovectomy with excision of lesion.

The Treatment of Infected Nonunion by the Ilizarov Technique / 대한정형외과학회잡지

The goal of treatment in infected nonunion include the elimination of infection, deformity and defects as same time as obtaining union. It is very difficult to obtain union and to correct deformity, infection and shortening in infected nonunion. The purpose of this study is to review the results of treatment of infected nonunion by the Ilizarov technique. Nineteen patients with infected nonunion were treated using Ilizarov external fixator from july 1991 to September 1993. Seven patients are undergoing treatment until now, so those were excluded from this data. Twelve patients were achieved bony union. Eleven cases were united and one case was failed with Ilizarov external fixator. We analyzed twelve cases. There were eleven males and one female, eight tibias and four femurs. Bony union was achieved by direct compression in six cases. Six cases were treated by bifocal osteosynthesis, but five cases were achieved bony union and one case was failed. So, we achieved bony union with intramedullary nailing and bone graft. The results were summarized as follows; 1. Eleven cases of infected nonunion were united with Ilizarov external fixator. The mean time to union of infected nonunion site was 10. 8 months. 2. The average bone lengthening of six cases was 64mm, ranging from 15mm to 110mm. The healing index averaged l. 64 month/Cm. 3, The bone results were excellent in six cases, good in five cases, poor in one case. The functional results were excellent in four cases, good in seven cases, fair in one case. 4. In all cases, we experienced difficulties. So we concluded that Ilizarov technique for infected nonunion is a valid procedure for control of infection, union, bone defect and deformity.

Clinical analysis of Canal Filling of Cementless Femoral Stem / 대한정형외과학회잡지

We Studied 48 patients(62 hips) who were performed hip arthroplasties at the Department of Orthopaedic Surgery, Soonchunhyang University hospital from February 1990 to August 1992. The purpose of the present study was to compare canal filling ratio and clinical results of cases treated by cementless femoral stem with 19 Harris Galante(straight stem), 23 Anatomic(curved stem) and 20 Multilock (straight stem). The follow-up periods ranged from 12 months to 36 months. We assessed canal filling at metaphysis, mid-stem and distal canal, and clinical results according to canal filling. The results were as follows ; 1. The average filling ratio of the medullary canal by each type of stem in the coronal plane were as follows. Harris Galante ; 80. 5%, Anatomic ; 79. 4%, Multilock; 79. 8% in metaphysis. Harris Galante ; 88. 7%, Anatomic ; 88. 3%, Multilock ; 87. 3% in mid-stem. Harris Galante ; 95. 1%, Anatomic 90. 2%, Multilock ; 94. 5% in distal canal. At distal canal, the average canal filling of Harris Galante and Multilock were more excellent than Anatomic in coronal plane. 2. The average filling ratio of the medullary canal by each type of stem in the saggital plane were as follows. Harris Galante ; 64. 0%, Anatomic 69. 6%, Multilock ; 68. 6% in metaphysis. Harris Galante ; 79. 6%, Anatomic; 84. 5%, Multilock; 80. 2 in mid-stem. Harris Galante ; 78. 3%, Anatomic ; 82. 6%, Multilock ; 84. 5% in distal canal. At mid-stem, the average canal filling of Anatomic was more excellent than Multilock and Harris Galante. At metaphysis and distal canal, the average canal filling of Anatomic and Multilock were more excellent than Harris Galante in saggital plane. 3. The average Harris's hip scores of each type of stem at the final follow-up was 89. 9 in Harris Galante, 90. 3 in Anatomic and 91. 9 points in Multilock. There was no significance statistically(p>0.05). 4. The correlation between the average canal filling and thigh pain was not statistically significant (p>0. 05).

Cysticercosis at the Level of Spomdyloisthesis: A Case Repport / 대한정형외과학회잡지

Cysticercosis is due to a larva of Taenia Solium. It is frequently reported in developing countries. It usually affects subcutaneous tissue, muscles and brain. But, spinal cysticercosis is rare and is usually diagnosed at surgery. Authors experienced a case of spinal cysticercosis accompanied with spondylolistheses at the same level. Space occupying lesion and arachnoiditis, confirmed by MMCT and MRI, were noted at the same level of spondylolistheses. So, it was very hard to make dicision whether we should open up the dura or not.

Epidural Hemangioma: A Case Report / 대한정형외과학회잡지

Epidural hemangioma is a rare neoplasm which consists of 4% of epidural tumors and 12% of hemangiomas of vertebral column. But most of them are secondary involvement of epidural space by vertebral hemangioma and pure epidural hemangioma is very rare. Reported cases involve thoracic & lumbar level. Neural foramen & paraspinal region are usually invaded by the tumor mass. Clinical symptoms are similar to simple low back pain or disc herniation. Myelography, CT & MRI are helpful to make diagnosis but pathologic finding is important for final diagnosis. Authors are reporting a case of epidural hemangioma which was difficult to differentiate from HIVD by symptomatology & radiologic findings alone.

A Clinical Study of Judet Plate Fixation for Subtrochanteric Fractures of the Femur / 대한정형외과학회잡지

Fractures in the subtrochanteric region of the femur present more formidable problems in treatment than do other trochanteric fractures, because such severe stresses exit at the fracture site. Therefore, as a rule we prefer to treat subtrochanteric fractures by operative means if possible. Many internal fixation devices have been recommanded for use in subtrochanteric fractures and each of these devices have advantages in certain types of subtrochanteric fractures, and their selection should be based on the individual fracture anatomy. A total of 20 patients with fracture of the subtrochanteric region of the femur, who were treated by internal fixation with Judet plate between January 1982 and December 1988 have been reviewed. Our conclusions were as follows; 1. Average age was 38 years old and most common cause of injury was traffic accident. 2. Cast immobilization was done after Judet plate fixation. Partial weight bearing ambulation was enabled from POD 10 weeks and full weight bearing ambulation was enabled from POD 16 weeks. 3. 18 in 20 cases, primary bony union was happened and the mean duration of radiological bony union was 24 weeks. 4. 3 cases of complications, metal failure with refracture (2 cases) and screw loosening (1 case), were occured due to early weight bearing in the post operative course. 5. Judet plate fixation was gave satisfactory result in uncomminuted subtrochanteric fracture, especially Seinsheimer's type I, II-A,B,C or Fieldings type I, II. 6. From a consideration of these series, Judet plate showed easy to use, perfect adaptation and rigid fixation. We thought Judet plate is one of a good implants for rigid fixation of subtrochanteric fracture without severe medial cortical disruption.

Fibular Fixation in Comminuted Distal Tibial Fractures Affecting Ankle Joint / 대한정형외과학회잡지

The primary aims of fracture treatment include the restoration of normal anatomy and a return of function to the injuried as early as possible. In pilon fracture, various methods of treatment were developed to accomplish this purpose. Fibular fixstion is a rarely accepted mehtod in the treatment of pilon fractures because it can't provide rigid internal fixation, But it might be indicated when an open wound was : present medially over the distal tibia, the ligamentous attachments of distal fibula and medial malleolus to talus and calcaneus and of the distal tibiofibular syndesmosis are largely intict. Utilizing these attachment, Fibular fixation can stabilize comminuted fractures of distal tibia affecting ankle joint. This procedure is so effective and simple The author has used this technique in three instances for two years with excellent results. This is not an original method, but worthy of being remindful of the literature.

Clinical Studies on the Supracondylar Fractures of the Humerus in Chilldren / 대한정형외과학회잡지

Supracondylar fractures of the humerus is the most common elbow fractures in children. The fractures so designated are in the supracondylar area of the humerus just proximal to the elbow, and do not directly involve the joint or the distal humeral epiphysis. Unfortunately, it can also be one of the most difficult fractures to treat. And the catastrophic picture of Volkmann's ischemic contracture and nerve injuries associated with these fractures, as after successful reduction, the late complications of loss of elbow motion, the chage in carrying angle, myositis ossifgicans, and delayed ulnar nerve palsy still lie ahead. For the period of 4 years and 10 months from May 1979 to March 1985, 47 patients who had been treated for supracondylar fractures of the humerus at the Department of Orthopaedic Surgery, college of medicine, Soon Chun Hyang University Hospital, are presented, The results obtained are as follows; 1. Supracondylar fractures of the humerus frequently occured between the ages of 4 and 9 years (70.2%) and the sex ratio was 2.1: 1 in male to female. 2. Of all fratures, 89.4% were the extension type and the left side was predominent in 55.3% than right. 3. According to the Holmberg clasification, Group 1 was 6 cases(12.8%), 10 cases(21.3%) in Group 2, 11 cases(23.4%) in Group 3, and 20 cases(42.5%) in Group 4. 4. Closed reduction with percutaneous pinning showed little changes in carrying angle. 5. Limitation of motion was most frequent complication after closed reduction with plaster cast immobilization. 6. By the modified Mitchell and Adams' criteria for grading results, excellent were obtained in 55.3 %, good in 44.7%, and zero in unsatisfactory. 7. In the neurovascular injuries associated with fractue, there were 4 neural injuries, and 2 vascular injuries. In 4 traumatic neuropathies, median nerve was involved most commonly and the were recovered spontaneously within 5 weeks. 8. Average time from injury to reduction was 1.6 day and delayed reduction or operation made worse the prognosis in most cases.