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Injuries of the posterior cruciate ligament have almost universally been treated nonoperatively in the past due to indignity of this complex structure. Recent studies have shown new informations on the anantomical, histological, biomechanical characteristics of the Posterior cruciate ligament PCL), and thereby interest of reconstruction surgery is increasing. But intraarticular PCL reconstruction still remains one of the most challenging problems in knee surgery. Although, various types of graft and surgical techniques have been used for reconstruction, results of surgery has been variable. In this study, three different methods of graft fixation for PCL reconstruction are evaluated biomechanically to determine the effect on mechanical property of reconstructed PCL using 30 porcine knees. Grafts used in this study were bone-patellar tendon-bone fixed with interference screw and Achilles tendon tied with suture. Additionally, five original PCLs were also tested by Instron universal testing instrument to determine its mechanical proprety. Tensile test was performed at extended knee position. It was demonstrated that mechanical strength of bone-patellar tendon-bone graft is superior to that of Achilles tendon graft. All of the failures of bone-patellar tendon-bone graft and Achilles tendon graft occurred at tibial fixation site whereas original PCLs which failed at proximal midsubstance of ligament. In conclusion, tensile strength of Bone-patellar tendon-bone graft used for PCL reconstruction is higher than that of Achilles tendon but latter can be used in terms of as clinical meanings.
Achilles Tendon ; Bone-Patellar Tendon-Bone Grafts ; Knee ; Ligaments ; Posterior Cruciate Ligament* ; Sutures ; Tensile Strength ; Transplants*

4.Vitamin C Improves The Age-Related Impairment of Endothelium-Dependent Vasodilation in Elderly.

Young Keun ON ; Yong Seok KIM ; Do Youn OH ; Jin Oh CHOI ; Eui Seock HWANG ; Cheol Ho KIM

Journal of the Korean Geriatrics Society 2001;5(1):24-32

BACKGROUND: Aging is associated with increased cardiovascular risk and firmly established as a risk factor for the development of atherosclerosis. However the exact mechanism of age-related damage to the arterial wall and its relation to the atherosclerotic process are not well known.The endothelium plays an important role for the regulation of vascular tone and the endothelial function is impaired in the presence of risk factors early in the process of atherosclerosis. Assessment of endothelial function appears to be a valuable tool for the diagnosing and therapeutic monitoring of coronary artery disease. Anti-oxidants are known to improve endothelial dysfunction in atherosclerosis patients. The aim of this study was, (1) to evaluate the endothelial function in elderly, (2) to investigate whether vitamin C administration has benefit on the endothelial function in elderly. METHODS: The endothelial function was estimated using venous occlusion plethysmography(VOP) in 7 elderly and 7 young healthy volunteers. The strain guage was connected to plethysmograph to record the forearm volume change. A rapid cuff inflator was used to inflate the arm cuff to 40 mmHg instantaneuosly thus occluding venous return from the forearm. The measurement of forearm volume change was repeated for 7 times each stage. The change of the forearm blood flow(FBF) was measured with the acetylcholine infusion through brachial artery and also with intra-arterial vitamin C. RESULTS: Endothelium-dependent vasodilatation was significantly impaired in the elderly group compared to the young group(321 +/-17% in elderly group vs 509 +/-81%, mean+/-SEM) Forearm blood flow response to acetylcholine was significantly enhanced with inraarterial infusion of vitamin C in elderly group(321+/-17% in elderly group vs 78% in vitamin C) Coinfusion of L-NMMA, an inhibitor of nitric oxide synthase, blunted forearm blood flow response to acetylcholine. CONCLUSIONS: Even though the mechanisms leading to drpressed endothelial function in elderly remains to be elucidated, our study shows that vitamin C result in demonstrable improvement by a mechanism that is probably related to antioxidant activity.
Acetylcholine ; Aged* ; Aging ; Arm ; Ascorbic Acid* ; Atherosclerosis ; Brachial Artery ; Coronary Artery Disease ; Endothelium ; Forearm ; Healthy Volunteers ; Humans ; Nitric Oxide Synthase ; omega-N-Methylarginine ; Risk Factors ; Vasodilation* ; Vitamins*

A retrospective analysis was performed on 69 follow-up cases of ducal carcinoma in situ(DCIS) treated from Jan. 1981 to Dec. 1995 at Department of Surgery, Seoul National University Hospital. The results are as follows. The mean age was 45.4 years that ranged from 28 to 68. The proportion of DCIS to breast cancer was increased from 1.3% to 7.2% for 15 years. Clinical presentations of DCIS were mass, nipple discharge and suspicious mammographic findings. Patients presenting mass were decreased, while mammographically detected DCIS were increased. In 49.3% of cases, the tumor size was smaller than 2cm and in 21.3% of the cases, the tumor was not palpable. Treatment modality was changed to more conservative procedures. All of the patients survived well without local recurrence or distant metastasis for a mean follow-up of 36.3 months(range 7 to 146). Histopathologic review was also performed on 52 cases of which paraffin blocks were saved, by one pathologist and diagnosis was confirmed. Pure DCIS composed 16 cases(30.8%), and DCIS with microinvasion was 36 cases(69.2%). Clinical presentation of DCIS, such as age, nipple discharge, calcification on mammography and mass size were not related to the microinvasion, but mass palpability was related to microinvasion(p=0.018). There was no histopathologic features to predict progression to invasive carcinoma, regardless of comedo type, histologic grade and nuclear grade. The expression of cathepsin-D, nm23, p53 and c-erbB-2 protein, was also evaluated using immunohistochemical methods. The relationship between expression of immunohistochemical antibodies and prognostic variables such as tumor size, histologic grade, nuclear grade, and microinvasion was assessed. The overexpression of c-erbB-2 protein was associated with lower nuclear grade(p=0.033), and a strong correlation was seen between tumor size and cathepsin-D and p53 protein(p=0.035, p=0.016). In this study, we conclude that the fine classification and analysis of DCIS subtype, not only by histopathologic but also by immunohistochemical study can be helpful to predict biological behaviour of DCIS and decide the modality of treatment.
Antibodies ; Breast ; Breast Neoplasms ; Carcinoma in Situ* ; Carcinoma, Intraductal, Noninfiltrating ; Classification ; Diagnosis ; Follow-Up Studies ; Humans ; Mammography ; Neoplasm Metastasis ; Nipples ; Paraffin ; Receptor, erbB-2 ; Recurrence ; Retrospective Studies ; Seoul