[Effects of prostaglandin E2 and sodium hyaluronate on bradykinin induced knee joint pain in rat].

We studied effects of prostaglandin E2 and sodium hyaluronate on the reactive muscle activity induced by intra-articular injection of bradykinin into the knee joint of rat. An animal model was developed to evaluate knee joint pain. In unanesthetized and spinalized rat, bradykinin (BK) was injected into the knee joint and the duration of the reactive activity of the knee flexor was evaluated. The duration of the reaction was elongated dependent on the injected BK dosage (0.025-2.5 micrograms). When prostaglandin E2 (PG E2) was injected with BK, the duration of the reaction increased significantly (p < 0.01). In contrast, sodium hyaluronate (Na-HA: average MW 900 kD) injected into the joint 3-24 hours in advance significantly inhibited the BK induced reaction (p < 0.05-0.01). A histological study demonstrated the fluorescein-labeled Na-HA diffusely infiltrating into the surface of the soft tissue. From these results, the animal model used in the present study was valuable to evaluate quantitatively knee joint pain. Furthermore, the sensitizing effect of PG E2 and the inhibitory effect of Na-HA on joint pain was objectively demonstrated.

[Effect of 1 alpha-OH-D3 on the bone metabolism after high tibial osteotomy].

The effect of 1-hydroxycholecalciferol (1 alpha-OH-D3) on bone metabolism during osteotomized bone healing was investigated. The study based on 19 female patients with gonarthrosis who underwent the high tibial osteotomy. In 10 selected randomly from these patients 1 alpha-OH-D3 (1.0 micrograms/day) was administered before and after the surgery. After operation the changes in bone density (by MD-method) and biochemical parameters were followed. In the non-treated group the serum level of [Ca] x [P] product temporarily decreased at 3 days after surgery. Average bone density at two months after the surgery was 8.8% lower than the preoperative value. In contrast, 1 alpha-OH-D3 treated group showed significantly less decrease of serum [Ca] x [P] product at the third day than the control group and no significant decrease of bone density at two months after the operation. From these results, it was concluded that the 1 alpha-OH-D3 suppresses the decrease of serum Ca and P level and systemic osteopenia after osteotomy and may have an beneficial effect on fracture healing.

The physiology of mechanoreceptors in the anterior cruciate ligament. An experimental study in decerebrate-spinalised animals.

The physiological role of mechanoreceptors in the anterior cruciate ligament (ACL) was studied in unanaesthetised decerebrate-spinalised cats and dogs. Tonic activity in the quadriceps and the hamstring increased in response to physiological loading of the ACL. Evoked potentials in the posterior articular nerve (PAN) were elicited by electrical stimulation of the surface of the ligament. ACL loading also induced significant discharges from the PAN. The results suggest that ACL loading has an excitatory effect on the thigh muscles through a multimotor neurone output, and that the PAN is one of the afferent routes from the mechanoreceptors of the ACL. The ACL-muscle reflex may therefore play a physiological role in maintaining knee kinematics.

Problems with repeated arthroscopic surgery in the discoid meniscus.

To identify the main causes of repeated arthroscopic surgery of the knee joint and to find out the points of therapeutic approaches, we evaluated 139 patients who underwent arthroscopic meniscectomy in our department and in affiliated hospitals between 1983 and 1987. Two or more arthroscopic surgeries were needed in 9 knees of 8 patients (6.5%). In 5 knees with no known injuries, the primary reason for repeated surgery was horizontal tears of remnant meniscus after partial resection of lateral discoid meniscus. The most appropriate initial treatment for lateral discoid menisci in cases without tear should be observation of the clinical course with minimal treatment using diagnostic arthroscopy.

Specificity of antibodies to type II collagen in rheumatoid arthritis.

To reassess the role of autoantibodies to type II collagen in the pathogenesis of diseases, we studied antibodies from patients with rheumatoid arthritis (RA) and from patients with relapsing polychondritis for species specificity and collagen type specificity, using an improved enzyme-linked immunosorbent assay. Antibodies were found in the sera of 15% of the RA patients and 50% of the relapsing polychondritis patients, as well as in the cartilage of 69% of the RA patients examined. Reaction with both homologous and heterologous type II collagens was common. Analysis of 19 selected RA sera revealed that autoantibodies were generally associated with specific antibodies to some species of heterologous type II collagen. In contrast, antibodies found in 4% of the non-RA controls were specific for either bovine or chick type II collagen. These findings indicate that autoantibody formation in RA and relapsing polychondritis may occur as a result of an immune response to heterologous type II collagen. However, since RA and relapsing polychondritis patient sera differed in their reactivity with the cyanogen bromide-digested peptides, it is possible that the clinical manifestation of collagen autoimmunity might be influenced by the epitope specificity of the antibodies.

[Effects of cefotaxime on the coagulation system, especially their dependence on vitamin K-related factors].

The authors administered cefotaxime to 20 children and studied laboratory parameters concerning peripheral blood: hemoglobin count, blood platelet count, red blood cell count, and hematocrit value, and the coagulation system: protein induced by vitamin K deficiency or by the presence of a vitamin K antagonist II (PIVKA II), hepaplastin test (HPT), prothrombin time (PT) and active partial thromboplastin time (APTT). The results obtained are summarized as follows: 1. Peripheral blood No abnormal values were observed. 2. Coagulation system (1) PIVKA II: In all cases, PIVKA II was negative. (2) HPT, PT and APTT: In all cases, no significant changes of these values which would suggest the tendency for prolonged bleeding were observed.