Teiji Kato

Production of monocyte chemoattractant protein-1 by malignant fibrous histiocytoma: relation to the origin of histiocyte-like cells.

Human malignant fibrous histiocytoma (MFH) comprise both fibroblast-like cells and histiocyte-like cells. We previously showed that the latter are not neoplastic cells, but are infiltrating macrophages. Since migration of blood monocytes into the tumor might be a response to a locally elaborated monocyte chemoattractant, we designed experiments to determine if the fibroblast-like tumor cells produced a chemoattractant for human monocytes. Malignant fibrous histiocytoma from three patients was put into culture. Cells of all three lines had a spindle shape, and showed no reactivity with antibodies against macrophages (MAC387), HLA-DR (LN3), or leukocyte common antigen. Immunohistochemically, they stained with antibody against human monocyte chemoattractant protein-1 (MCP-1). Culture supernatants of the three cell lines had chemotactic activity for monocytes. This activity was due to MCP-1, since it was absorbed by an anti-MCP-1 column. The production of MCP-1 by MFH tumor lines was confirmed by immunoprecipitation of metabolically labeled MCP-1. These results suggest that the histiocyte-like cells are the infiltrated macrophages that originate from blood monocytes attracted by tumor-derived MCP-1.

Effects of a hydroxyl radical scavenger, EPC-K1, and neutrophil depletion on reperfusion injury in rat skeletal muscle

Oxygen free radicals (OFR) and neutrophils are potent sources of reperfusion injury. We compared the effect of EPC-K1, a new OFR scavenger, and neutrophil depletion on the reperfusion injury in skeletal muscle, using an ischemic revascularized hindlimb model in rats. Warm ischemia, produced by vascular pedicle clamping, was sustained for 4 h. After 24 h of reperfusion, muscle function and damage were evaluated in 4 groups: a sham operation group, a control study group, a group treated by EPC-K1 (EPC group), and a group that received nitrogen mustard to induce neutropenia (NM group). Both the EPC and NM groups had limited muscle damage compared to the control group. The EPC group preserved muscle function significantly better than the control group and the mean isometric tetanic tension in the EPC group appeared to be higher than that in the NM group. Furthermore, levels of lipid peroxides in muscle and serum, and muscle edema in the EPC group, were significantly lower than in the NM group. Histological examinations supported these results. These findings suggest that limiting OFR generation by EPC-K1 in the early phase of reoxygenation is more potent than depletion of neutrophils in reducing reperfusion injury.

The Effect of Perfusion with UW Solution on the Skeletal Muscle and Vascular Endothelial Exocrine Function in Rat Hindlimbs

BACKGROUND The effect of University of Wisconsin (UW) solution perfusion for extremity preservation is still unknown although it is widely used. The purpose of this study is to examine the effect of UW solution perfusion on skeletal muscle preservation in a rat model. MATERIALS AND METHODS Rat hindlimbs were amputated and either preserved with UW solution perfusion (UW perfusion group) or given no perfusion (no-perfusion group) for 5 h at 25 degrees C. They were then transplanted to other isogeneic rats. ATP in the muscle and serum creatine phosphokinase were measured after 24 h of reperfusion. The vascular endothelial function of the femoral artery rings was measured before and after 24 h of reperfusion in the presence or absence of indomethacin (cyclooxygenase inhibitor) and L-NMMA (nitric oxide synthase inhibitor). TEA (calcium-activated potassium channel inhibitor) was also used to verify the vasodilator function. Reperfusion blood flow was monitored during the first 2 h of reperfusion. RESULTS ATP in the UW perfusion group was significantly decreased after 24 h of reperfusion, while that in the no-perfusion group recovered. Reperfusion blood flow in the UW solution perfusion group was significantly lower than that in the no-perfusion group. Acetylcholine-induced relaxation in the UW perfusion group was significantly reduced before and after 24 h of reperfusion compared to that in the no-perfusion group and was mostly diminished by indomethacin and L-NMMA administration. CONCLUSIONS Skeletal muscle injury is augmented by UW solution perfusion, probably due to deterioration of the vascular endothelial function resulting in blood supply diminution.

PAINFUL HETEROTOPIC PACINIAN CORPUSCLE IN THE HAND: A REPORT OF THREE CASES

Severe pain in the finger caused by an abnormal Pacinian corpuscle is a rare condition. We have recently encountered three patients diagnosed with a heterotopic Pacinian corpuscle, based on histopathological findings. When making a differential diagnosis of unexplained severe pain in the finger, abnormal Pacinian corpuscles must be taken into account in addition to glomus tumour and other types of painful soft-tissue tumour.

INVESTIGATION OF ENDOTHELIAL CONTROL OF BONE BLOOD FLOW: DEVELOPMENT OF A RABBIT TIBIA EX VIVO PERFUSION MODEL

An ex vivo rabbit tibia perfusion model was developed to investigate the vascular reactivity and vascular endothelial function of bone tissue. The tibiae of 36 adult New Zealand rabbits were isolated and perfused through the cannulated nutrient artery at a constant flow rate in an organ chamber. The increase in perfusion pressure caused by graded doses of norepinephrine produced a dose response curve, which was first recorded under control condition, and then during perfusion with acetylcholine (ACh), NG-monomethyl-L-arginine acetate (L-NMMA), and/or L-arginine (nitric oxide precursor) infusion. The optimal flow rate for rabbit tibia was 0.3 to 0.4 ml/min, depending on the weight of the tibia. The perfusion baseline and the norepinephrine dose-response curve (NEDRC) remained stable for at least eight hours. Acetylcholine (1 × 10-5M) infusion attenuated the NEDRC (33 ± 5%) for 1.5 hours. Thereafter, the vasorelaxant effect of ACh diminished due to depletion of nitric oxide, and ultimately caused an increase in the NEDRC due to a vasoconstrictive action. The rebound vasoconstriction did not occur in the presence of constant L-arginine infusion, which maintained nitric oxide production, and ACh continued to attenuate the NEDRC (36 ± 4.5%) for at least eight hours. L-NMMA, which inhibits the synthesis of nitric oxide, increased the vasoconstrictive effect of norepinephrine significantly (155 ± 16%). The rabbit tibia ex vivo model seems ideal for the study of bone vascular bed activity, due to its stable baseline, reliable NEDRC and cost efficiency. We have further demonstrated that the intraosseous vascular endothelium of rabbit tibia produces nitric oxide as one method of regulating bone perfusion.

Acute changes in the axonal cytoskeleton after mild stretching of the rat brachial plexus

We have developed an animal model to investigate acute changes in the axonal cytoskeleton caused by a mild stretching of the peripheral nerve in the upper limbs of rats. Rat forelimbs were continuously stretched at 2 N for 1 h. Thereafter, a part of the brachial plexus and median nerve were harvested and processed for electron microscopic analysis. The total number of microtubules in the brachial plexus decreased to 55% of that of the control animals (p<0.05) without change in the number of neurofilaments. No significant changes in microtubules or neurofilaments were observed in the median nerve. By Western blotting analysis, the amount of tau protein in the stretch group significantly decreased in the brachial plexus but not in the median nerve. However, no significant changes in the amount of tubulin protein were observed in either the brachial plexus or median nerve. These results suggest that the microtubules were depolymerized by stretching of the brachial plexus and that the depolymerization may have been mediated by the decrease in the tau protein.