Up-regulated uridine kinase gene identified by RLCS in the ventral horn after crush injury to rat sciatic nerves

Rat sciatic nerve crush injury is one of the models commonly employed for studying the mechanisms of nerve regeneration. In this study, we analyzed the temporal change of gene expression after injury in this model, to elucidate the molecular mechanisms involved in nerve regeneration. First, a cDNA analysis method, Restriction Landmark cDNA Scanning (RLCS), was applied to cells in the ventral horn of the spinal cord during a 7-day period after the crush injury. A total of 1991 cDNA species were detected as spots on gels, and 37 of these were shown to change after the injury. Temporally changed patterns were classified into three categories: the continuously up-regulated type (10 species), the transiently up-regulated type (22 species), and the down-regulated type (5 species). These complex patterns of gene expression demonstrated after the injury suggest that precise regulation in molecular pathways is required for accomplishing nerve regeneration. Secondly, the rat homologue of uridine kinase gene was identified as one of the up-regulated genes. Northern blot analysis on rat ventral horn tissue and brain revealed that the UK gene had three transcripts with different sizes (4.3, 1. 4, and 1.35 kb, respectively). All of the transcripts, especially the 4.3 kb one, were up-regulated mainly in a bimodal fashion during the 28-day period after the injury. The RLCS method that we employed in the present study shows promise as a means to fully analyze molecular changes in nerve regeneration in detail.

A method of tracking donor cells after simulated autologous transplantation: a study using synovial cells of transgenic rats

A transgenic rat was used as a transplantation donor to simulate autologous transplantation. The sex-matched transplantation between a female transgenic and a wild-type rat can theoretically be regarded as an autologous transplantation due to the genetic agreement of these rats except for the non-protein-producing transgenes. Transgene-containing synovial cells were tracked in the joint using this autologous transplantation model. The transgenes in the donor synovial cells were detected using in situ hybridization (ISH), while mitotic activities were simultaneously examined by immunodetection of 5-bromo-2'-deoxyuridine (BrdU). A defect was generated in the knee joint capsule of a Fischer 344 (wild-type) rat. The synovium of a transgenic rat was sutured to the defect of the wild-type rat in group 1 and was allowed to free float in the joint in group 2. A large number of BrdU-labeled, transgene-containing synovial cells were detected in both groups at 3 days. The number of these cells then decreased, but they could still be identified even at 4 weeks after autologous transplantation. These results indicated that transplanted synovial cells were viable in the joint for at least 4 weeks. Furthermore, the transgenic rat was shown to be an effective animal model for distinguishing the extrinsic from the intrinsic cells in the cellular intermixed tissues in vivo. The combined method of ISH for detecting transgene-containing cells and the immunohistochemistry of BrdU for detecting proliferating cells was also shown to be effective for tracking the viability of extrinsic cells after autologous transplantation.

Unusual proximal tibiofibular synostosis

Proximal tibiofibular synostosis without multiple hereditary exostosis is extremely rare and only 7 cases have been reported in the literature. All of the previously reported cases accompanied deformities such as distal positioning of the proximal tibiofibular joint, leg length discrepancy, bowing of the fibula, and valgus deformity of the knee. The present case of a 24-year-old man had neither a history of trauma nor deformity around the knee. Therefore, it was suggested that this type of synostosis occurred after epiphyseal plate closure.

In vitro antiplatelet profile of FR171113, a novel non-peptide thrombin receptor antagonist

Synthetic peptides (5 to 14 amino acids), identical in sequence to the new amino-terminus of the thrombin receptor generated following cleavage by thrombin, act as thrombin receptor agonist peptides. Whilst thrombin receptor antagonist peptides are known, non-peptide thrombin receptor antagonists have yet to be described. In the present study, we compared the antiplatelet effects of 3-(4-chlorophenyl)-2-(2,4-dichlorobenzoylimino)-5-(methoxycarbonyl methylene)-1,3-thiazolidin-4-one (FR171113), a novel non-peptide thrombin receptor antagonist, with the known thrombin receptor antagonist 3-mercapto-propionyl-Phe-Cha-Cha-Arg-Asn-Pro-Asn-Asp-Lys-Tyr-OH (C186-65), and argatroban, a specific protease inhibitor of thrombin. FR171113 and C186-65 inhibited thrombin-induced platelet aggregation (IC(50)=0.29 microM and 15 microM, respectively) and Ser-Phe-Leu-Leu-Arg-Asn-NH(2) [a synthetic thrombin receptor agonist peptide (TRAP-6)] induced platelet aggregation (0.15 microM and 20 microM, respectively) in human washed platelets. Argatroban potently inhibited thrombin-induced platelet aggregation (IC(50)=3.5 nM), but did not inhibit TRAP-6-induced aggregation even at 100 microM. In contrast, these compounds did not show inhibitory effects on ADP- and collagen-induced aggregation in human platelet-rich plasma even at 100 microM. FR171113 caused a parallel shift to the right of the concentration-response curve describing aggregation induced by TRAP-6. The Schild plot of the data had a slope of -0.840 (r=0.98) and the pA(2) was 7.29. In protease activity studies using a chromogenic substrate, argatroban inhibited thrombin protease activity in a dose-dependent manner, whereas FR171113 and C186-65 were inactive, even at 100 microM. Additionally, only argatroban displayed dose-dependent prolongation of thrombin time, activated partial thromboplastin time and prothrombin time. FR171113 and C186-65 showed no effects, even at a concentration of 100 microM. These results suggest that FR171113 has a similar mode of action to C186-65, but with more potent antiplatelet activity. In conclusion, FR171113 is suggested to be the first example of a non-peptide thrombin receptor antagonist.

Acquisition of multidrug resistance in osteosarcomas, analyzed by doxorubicin binding assay, and histologic response to chemotherapy

BACKGROUND

The mechanism by which multidrug resistance is acquired in human osteosarcomas remains unclear. In this study, we analyzed the changes in doxorubicin (DOX) binding ability (%DB), showing chemosensitivity before and after chemotherapy with DOX and cisplatin (CDDP), and evaluated the histologic response of human osteosarcomas to chemotherapy.

MATERIALS AND METHODS

Eight osteosarcomas were analyzed. %DB by the DOX binding assay was measured in fresh tumor tissues at biopsy and at resection after preoperative chemotherapy. The histologic response to chemotherapy was also evaluated.

RESULTS

Changes in %DB before and after chemotherapy were classified into 4 patterns; A: high (> 80%) to low (< 80%), B: high to high, C: low to low, D: low to high. The two tumors, classified as type A and B were responders (> 90% necrosis), whereas the 6 tumors of type C and D were classified as non-responders (< 90% necrosis). Based on these data, we speculated that the fraction of cell populations with different chemosensitivities to DOX and CDDP varied and found that type B tumors have no population of resistant cells, whereas type C tumors have a large fraction of resistant cells.

CONCLUSION

We concluded that osteosarcomas are composed of mixed cell populations with different chemosensitivities to anticancer agents and also that survival of multidrug resistant cell populations may be the most important mechanism in acquisition of multidrug resistance of osteosarcomas after chemotherapy.

A new arthroscopic method for reconstructing the anterior and posterior cruciate ligaments using a single-incision technique: simultaneous grafting of the autogenous semitendinosus and patellar tendons

We established a simultaneous reconstruction method for ruptured anterior and posterior cruciate ligaments (ACL, PCL) using a single-incision technique. Residual PCL was used to determine the position of bone tunnel for ACL reconstruction. The bone tunnel position on the tibia for PCL reconstruction was arthroscopically confirmed by conducting through debridement from the posteromedial portal. Reconstruction substitutes were patellar-tendon bone-tendon-bone for ACL, and semitendinosus tendon for PCL. In the fixation procedure, the PCL substitute was fixed using the Endobutton (Smith & Nephew, Andover, MA) and a ceramic button, and the ACL substitute was fixed with an interference screw. During the surgery, radiographic monitoring and the PCL guide system were not required.

Clinical outcome of total scapulectomy in 10 patients with primary malignant bone and soft-tissue tumors

BACKGROUND AND OBJECTIVES

Limb reconstruction after total scapulectomy for malignant bone and soft-tissue tumors around the scapula is difficult. This study was undertaken to clarify the clinical results of total scapulectomy in patients with malignant bone and soft-tissue tumors around the shoulder girdle in our institute between 1984 and 1998.

METHODS

Ten patients undergoing total scapulectomy had an age range of 12-82 years (average = 56 years). There were 5 cases of bone tumor and 5 cases of soft-tissue tumor. The follow-up period ranged from 8 months to 13 years 5 months.

RESULTS

Seven patients are currently alive; the remaining 3 patients died of other diseases. One case of local recurrence was detected. The 2-year survival rate of all cases was 78.8%, and the 5-year survival rate was 52.5%. The average function evaluated by Enneking's criteria was 64.6%. Although the range of motion in the shoulder joint was seriously limited in all patients, the elbow and hand functions were almost normal. Recently, we have used a bone-anchoring system to suture between the clavicle and muscles, including the biceps, triceps, and deltoid muscles.

CONCLUSIONS

Patients who undergo total scapulectomy may achieve much better upper limb function than those who undergo forequarter amputation (interscapulothoracic amputation).

Improving the cytometric detection of doxorubicin resistance in osteosarcoma cells by determining cellular doxorubicin/DNA ratio

To study the influence of cellular DNA content on the accumulation and efficacy of doxorubicin (DOX), we characterized P-glycoprotein (Pgp)-positive and -negative murine osteosarcoma cell clones that had a different DNA index. Statistical analysis demonstrated that the cytotoxic effects of DOX correlated significantly with the ratio of intracellular DOX accumulation divided by the cellular DNA content (DOX/DNA ratio) (P = 0.001), but not with the intracellular DOX accumulation (P = 0.16). We also tested this relationship for Pgp-negative human osteosarcoma cell lines with a different DNA ploidy, and found that these Pgp-negative cell lines all had similar DOX/DNA ratios. These results indicate that the DOX/DNA ratio is a determinant for the effects of DOX in osteosarcoma cells, regardless of their Pgp status and DNA ploidy. Thus, consideration of the cellular DNA content as well as the intracellular DOX accumulation is important to accurately detect DOX resistance.

A clinicopathologic study of transient osteoporosis of the hip

OBJECTIVE

It has been proposed that transient osteoporosis of the hip (TOH) may represent the early reversible phase of osteonecrosis of the femoral head (ON). The purpose of this study was to investigate the clinicopathologic characteristics of three cases of TOH.

DESIGN AND PATIENTS

A bone biopsy was performed on three patients who had been diagnosed as having TOH based on the clinical course, radiograph, bone scintigram, and MR images. The biopsy specimens were studied histopathologically by light and electron microscopy.

RESULTS

The most characteristic feature of TOH was focal areas of thin and disconnected bone trabeculae covered by osteoid seams and active osteoblasts. The surrounding bone marrow tissue showed edematous changes and mild fibrosis, frequently associated with vascular congestion and/or interstitial hemorrhage. No osteonecrotic region was observed in either the bone trabeculae or the bone marrow tissue. All patients have improved clinically and in the 3.5-9 years of follow-up have shown no evidence of ON.

CONCLUSIONS

This study supports the concept that transient osteoporosis of the hip is a distinct entity.

Radial-sequence magnetic resonance imaging in evaluation of acetabular labrum

We investigated the usefulness of a radial-sequence magnetic resonance imaging (MRI) technique in the visualization of the acetabular labrum, which surrounds the acetabulum. In 22 hip joints of 12 volunteers, T2-weighted images were obtained on 24 radial planes of the acetabular rim, set at 15 degrees -intervals, using the small tip angle gradient echo method. We examined 7 planes in the weight-bearing portion. The acetabular labrum in the weight-bearing portion was depicted in good contrast to the surrounding tissues. The shape of the labrum differed among individuals and also in the anterior and posterior portions of the labrum. The signal intensity of the labrum was low or partially moderate. There was a high signal intensity band on the base of the acetabular labrum in several portions, which should be carefully interpreted to avoid confusion with abnormality. We concluded that radial-sequence MRI could be a useful technique for evaluation of the condition of the acetabular labrum in the weight-bearing portion.

Association between plasma homocysteine concentration and carotid atherosclerosis in hemodialysis patients

Accelerated atherosclerosis is a major risk for uremic patients undergoing long-term hemodialysis. Because hyperhomocysteinemia may influence this condition, 168 such patients were examined for a possible association between plasma total homocysteine concentration (tHcy) and conventional cardiovascular risk factors. Generalized atherosclerosis was indicated by excessive intimal-medial wall thickness (IMT) of the extracranial carotid artery as measured by B-mode ultrasonography. The results documented tHcy in these patients of 33.0+/-16.9 micromol/L, a significantly higher amount than that of healthy subjects (11.0+/-3.1 micromol/L, p<0.0001). The patients' carotid maximum IMT was 1.79+/-1.16 mm. In multiple regression analyses with forward elimination procedure, carotid maximum IMT was clearly related to age (r = 0.417, p<0.0001), systolic blood pressure (r = 0.262, p = 0.0043), smoking (r = 0.177, p = 0.0076), duration of hemodialysis (r = 0.083, p = 0.0045), and tHcy (r = 0.195, p = 0.0021). These 5 factors accounted for 36.0% of the variation in carotid maximum IMT. Factors determined as unrelated were male gender, diastolic blood pressure, body mass index, total and HDL cholesterol, triglyceride, lipoprotein(a), uric acid, calcium, inorganic phosphate, and parathyroid hormone. Therefore hyperhomocysteinemia, along with advanced age, systolic hypertension and smoking aggravates atherosclerosis in chronic uremic patients.

Two cases of secondary angiosarcoma arising from fibrous dysplasia

Angiosarcoma associated with fibrous dysplasia is very rare. We have recently experienced two cases of angiosarcoma that secondarily arose from fibrous dysplasia. The first patient, a 55 year-old man, had noticed a deformity in the right upper arm since he was five years old. At the age of 25 years, polyostotic fibrous dysplasia was diagnosed by X-ray examination. The patient complained of swelling and pain around the left shoulder. The diaphysis of the humerus was mostly non-observable due to severe bone destruction by tumor invasion and there was a large soft tissue tumor. Biopsy examination revealed grade II or III hemangioendothelioma with typical histologic findings of fibrous dysplasia. After interscapulothoracic amputation for wide tumor resection, he died of DIC. Autopsy revealed multiple liver metastatic lesions of angiosarcoma. The second patient was a 66-year-old woman. She presented with a pathological fracture in the right tibia, due to an osteolytic lesion with cortical bone swelling and thinning. The histologic diagnosis was fibrous dysplasia without any sarcomatous changes. However, after a 3-time recurrence, angiosarcoma arose from the same lesion. She is now still alive with disease-free period of 6.5 years after amputation.

Usefulness of cytofluorometric DNA ploidy analysis in distinguishing benign cartilaginous tumors from chondrosarcomas

In this study, we undertook to prove the usefulness of cytofluorometric DNA ploidy analysis in distinguishing benign cartilaginous tumors from chondrosarcomas. We analyzed the DNA ploidy of 47 cartilaginous tumors using DNA cytofluorometry, which is more sensitive than flow cytometry. All of these tumors were classified into six groups on the basis of clinical, radiologic, and histologic criteria. The 25 tumors in the No. 1 group showed no histologic signs of malignancy regardless of their clinical signs. The four tumors in the No. 2 group showed histologic signs of malignancy, but had benign clinical signs like small bone origin or Ollier's disease. The No. 3 group (13 tumors), No. 4 group (four tumors), and No. 5 group (three tumors) were conventional grade I, II, and III chondrosarcomas, respectively, and the No. 6 group included three dedifferentiated chondrosarcomas. Tumor cells isolated from fresh tumor materials treated with papain and collagenase were smeared on a glass slide and their nuclear DNA was stained with propidium iodide. The DNA content of each cell was measured by a cytofluorometer as fluorescence intensity. The results of this study showed that all of the tumors in the No. 1 group had a diploid pattern with a significantly lower (P<.001) cell proliferative activity than the grade I chondrosarcomas in the No. 3 group, all of which had a diploid pattern. Cytofluorometric analysis also indicated that grade II and III chondrosarcomas in the No. 4 and 5 groups had a higher frequency of hyperdiploid cells (%HDC), including aneuploid and polyploid cells than grade I chondrosarcomas. Importantly, all of the grade I chondrosarcomas showed a %HDC >8%, whereas all of the tumors in the No. 1 and 2 groups showed a %HDC <8%. Therefore, we believe that a %HDC value of 8% is borderline between biologically benign and malignant states in cartilaginous tumors. Four of five patients with aneuploid chondrosarcoma had tumor recurrence and two of these patients died of metastatic disease, although all of the patients except for one with diploid chondrosarcoma were continuously disease free after surgery. Based on these results, we concluded that the data of DNA ploidy analysis, especially cell proliferative activity expressed as %HDC, is more reliable and clinically more useful than the histologic and clinical signs of malignancy in distinguishing benign cartilaginous tumors from chondrosarcomas and even from low grade chondrosarcomas.

Improvement of myocardial fatty acid metabolism through L-carnitine administration to chronic hemodialysis patients

The concentration of carnitine, which is essential to fatty acid metabolism, can decrease markedly in patients on long-term hemodialysis coincident with life-threatening cardiac damage. However, administration of L-carnitine improves the myocardial function of these patients. To evaluate the underlying events of this phenomenon, we used recently developed technology, (123)I-labeled beta-methyl-p-iodophenyl-pentadecanoic acid (BMIPP) myocardial scintigraphy, as a test of myocardial fatty acid metabolism. Our results showed that the free carnitine concentration (19.2 +/- 6.5 micromol/l) was lower in 11 chronically dialyzed patients than in 8 healthy controls (49.3 +/- 7.7 micromol/l, p < 0. 0001). Additionally the heart to mediastinal ratio (H/M) of BMIPP was higher for these patients than for the controls (1.91 +/- 0.19 vs. 1.52 +/- 0.24, p < 0.005), and the patients' washout rate (WOR) of BMIPP was lower (17.2 +/- 6.0 vs. 22.8 +/- 4.2%, p < 0.05). After L-carnitine was administered orally to the patients at doses of 1 g/day for 1 month and 0.5 g/day for the following month, the concentration of free carnitine in their sera increased to 85.4 +/- 27.0 micromol/l (p < 0.0001). Although the H/M ratio did not change (1.89 +/- 0.20) with this treatment, their WOR increased to 21.9 +/- 6.6% (p < 0.001), similar to that of controls. The left ventricular end-diastolic dimension and left ventricular fractional shortening remained unchanged, as shown by echocardiography. The results presented here denote that a carnitine deficiency in chronically hemodialyzed patients disrupts their myocardial fatty acid metabolism, which is improved by L-carnitine supplementation.

Control of delivered gene expression in chondrocytes using heat shock protein 70B promoter

OBJECTIVE

To investigate whether the expressions of delivered Escherichia coli beta-galactosidase (LacZ) gene and transforming growth factor-beta1 (TGF-beta1) gene are regulated by the stress response of human chondrocyte-like cells (HCS-2/8) when heat shock protein 70B (HSP70B) promoter is inserted into the adenovirus vector.

METHODS

Two adenovirus vectors that contain either LacZ gene or TGF-beta1 gene regulated by HSP70B promoter were constructed. One of the adenovirus vectors was added to the culture of HCS-2/8 and gene transduced cells were produced. We applied heat stress (43 degrees C) to the transduced cells for 2 h and examined whether the expression of transduced LacZ and TGF-beta1 genes is affected by the stress, using 5 bromo-4-chloro-3-indolyl-beta-D-galactopyranoside (X-gal) staining, measurement of beta-galactosidase activity, Northern blotting, and ELISA.

RESULTS

The percentage of X-gal positive stained cells in LacZ gene-delivered cells with heat stress was significantly higher than in controls (no heat stress). With heat stress, beta-galactosidase activity increased significantly, and the band of exogenous TGF-beta1 mRNA became more apparent and the expression was maintained during the 24 h monitoring period. TGF-beta1 level in culture supernatant of TGF-beta1 gene-delivered cells with heat stress (5477.3+/-321.1 pg/ml) was significantly higher than in the controls (853.2+/-29.2 pg/ml).

CONCLUSION

HSP70B promoter could regulate the expression of delivered genes according to the intensity of heat stress.

Histiocyte reaction in rabbit femurs to UHMWPE, metal, and ceramic particles in different sizes

To assess the histologic reaction caused by biomaterial particles in different sizes around the bone-implant interface, we examined ultra-high molecular weight polyethylene (UHMWPE, average diameter of 11 microm), UHMWPE (99 microm), cobalt-chromium alloy (Co-Cr, 3.9 microm), stainless steel (SUS316L, 3.9 microm), alumina ceramics (3.9 microm), titanium alloy (Ti, 3.5 microm), Co-Cr (0.03 microm), and Ti (0.03 microm). After the longitudinal groove on a polymethylmethacrylate plug was filled with one type of the particles, the plug was inserted into the medullar canal of the distal end of rabbit femurs, and tissue block was resected 4 and 12 weeks after the insertion. Histiocytes were markedly accumulated around the particles of UHMWPE (11 microm), Co-Cr (3.9 microm), SUS316L (3.9 microm), Co-Cr (0.03 microm), and titanium alloy (0.03 microm). Around the UHMWPE particles (99 microm), a slight histiocytic reaction and bone formation were observed. Particles of alumina ceramics (3.9 microm) and titanium alloy (3.5 microm) which were in phagocytosable sizes also had few histiocytic reactions. Statistically, the material difference was more strongly related to the histiocyte reaction than to the particle size and calculated total surface area of particles. Our findings demonstrate that particles of different biomaterials and in different sizes induce different foreign-body histological reactions.

Lipoprotein(a) is a predictor for cardiovascular mortality of hemodialysis patients

BACKGROUND

Although hemodialysis (HD) patients have been associated with elevations in serum lipoprotein(a) [Lp(a)] levels, relatively little has been published on the link between Lp(a) and the risk for atherosclerotic cardiovascular death in HD patients.

METHODS

Lipoprotein(a) was measured in 390 HD patients. The relationship between Lp(a) and mortality (overall and cardiovascular) was determined during 28 months of prospective follow-up.

RESULTS

Hemodialysis patients demonstrated Lp(a) concentrations that were approximately two times as high as that of healthy controls (median, 16 vs. 8 mg/dl, P < 0.001; mean, 22.9 vs. 12.1 mg/dl, P < 0.01). Lp(a) showed a significant correlation between albumin, total cholesterol, low-density lipoprotein cholesterol, and C-reactive protein. The high-Lp(a) group [Lp(a) > or = 30 mg/dl] showed significantly higher mortality than the low-Lp(a) group [Lp(a) < 30 mg/dl] in a Kaplan-Meier survival analysis (P < 0.05). Multiple logistic regression analysis demonstrated albumin, age, and diabetic state as significant risk factors for overall death. However, if confined to atherosclerotic cardiovascular death, Lp(a) (P < 0.01), age, and diabetic state were the only independent contributors.

CONCLUSIONS

Lp(a) is an independent risk factor for atherosclerotic cardiovascular death in Japanese patients receiving chronic dialysis therapy.

Prognostic value of DNA ploidy response to chemotherapy in human osteosarcomas

We analyzed the DNA ploidy alterations after preoperative chemotherapy in 30 patients with non-metastatic osteosarcomas of the extremities. All of the patients received intensive chemotherapy with doxorubicin, cisplatin and methotrexate as well as wide tumor resection. DNA ploidy was determined by DNA cytofluorometry using isolated and smeared cells from biopsied and resected tumors after preoperative chemotherapy. The results showed that 12 diploid and nine non-diploid osteosarcomas did not change their ploidy pattern, but nine non-diploid tumors changed to a diploid pattern with the disappearance of the aneuploid cells. The nine patients with altered ploidy tumors had a better histologic response to chemotherapy and a better prognosis than the patients with non-altered tumors especially diploid tumors (P = 0.0138). Therefore, we conclude that a decrease in aneuploid cells after chemotherapy is closely correlated with a good prognosis in half of the cases of aneuploid osteosarcoma. These results also suggest that aneuploid cells are more chemosensitive than diploid cells in human osteosarcomas.

Preliminary report on usefulness of magnetic resonance imaging for outcome prediction in early-stage Legg-Calvé-Perthes disease

The usefulness of magnetic resonance imaging (MRI) for predicting prognosis was evaluated in 11 patients with unilateral early-stage Legg-Calvé-Perthes disease who were treated with a non-weight-bearing abduction brace. Six to 10 months after disease onset, severity of cartilage hypertrophy and physeal curvature of the femoral head were scored on MRI. Femoral head deformity was radiographically evaluated. Among five patients whose MRI score was 8 or greater, radiographic evaluation after the treatment was "poor" or "fair," whereas evaluation for the other six patients whose MRI score was 7 or less was "good." The MRI scores indicated possible occurrence of femoral head deformation. Treatment method should be considered carefully when the MRI score is high.

[Management of patient with acute myocardial infarction due to left main trunk obstruction]

Between April 1995 and March 1998, we experienced 13 cases of Acute Myocardial Infarction due to Left Main Trunk Obstruction (LMT-AMI). Two cases died before emergent intervention. Eight cases underwent emergent intervention (Plain Old Balloon Angioplasty (POBA) in five cases, Stenting in 3 cases); 2 cases died of acute occlusion of POBA site, 1 case survived by only POBA, and the other 5 cases underwent following Coronary Artery Bypass Grafting (CABG). 3 cases underwent only CABG with stable hemodynamics condition by Intraaortic balloon pumping (IABP) support. In a result, seven of eight CABG cases survived. Emergent stenting made the hemodynamics before CABG stable, and six-month's follow up angiogram showed occluded bypass grafts and patent stented sites in two of three cases. The combination therapy of emergent stenting and CABG will have to be evaluated in future.

Histiocyte reaction in rabbit femurs to UHMWPE, metal, and ceramic particles in different sizes

To assess the histologic reaction caused by biomaterial particles in different sizes around the bone-implant interface, we examined ultra-high molecular weight polyethylene (UHMWPE, average diameter of 11 microm), UHMWPE (99 microm), cobalt-chromium alloy (Co-Cr, 3.9 microm), stainless steel (SUS316L, 3.9 microm), alumina ceramics (3.9 microm), titanium alloy (Ti, 3.5 microm), Co-Cr (0.03 microm), and Ti (0.03 microm). After the longitudinal groove on a polymethylmethacrylate plug was filled with one type of the particles, the plug was inserted into the medullar canal of the distal end of rabbit femurs, and tissue block was resected 4 and 12 weeks after the insertion. Histiocytes were markedly accumulated around the particles of UHMWPE (11 microm), Co-Cr (3.9 microm), SUS316L (3.9 microm), Co-Cr (0.03 microm), and titanium alloy (0.03 microm). Around the UHMWPE particles (99 microm), a slight histiocytic reaction and bone formation were observed. Particles of alumina ceramics (3.9 microm) and titanium alloy (3.5 microm) which were in phagocytosable sizes also had few histiocytic reactions. Statistically, the material difference was more strongly related to the histiocyte reaction than to the particle size and calculated total surface area of particles. Our findings demonstrate that particles of different biomaterials and in different sizes induce different foreign-body histological reactions.

Distribution of synaptosomal-associated protein 25 in nerve growth cones and reduction of neurite outgrowth by botulinum neurotoxin A without altering growth cone morphology in dorsal root ganglion neurons and PC-12 cells

Synaptosomal-associated protein 25 has been regarded as one of the target-associated soluble N-ethylmaleimide-sensitive fusion attachment protein receptors essential for exocytosis of vesicles in synapses. We have previously reported that cleavage of syntaxin, which is another target-associated soluble N-ethylmaleimide-sensitive fusion attachment protein receptor, with botulinum neurotoxin C1 resulted in inhibition of neurite extension and morphological changes including growth cone collapse and large vacuole formation. As an attempt to explore the mechanism of growth cone extension, we examined the ultrastructural localization of synaptosomal-associated protein 25 in growth cones with or without treatment of botulinum neurotoxin A, which cleaves synaptosomal-associated protein 25. In dorsal root ganglion neurons, light microscopy demonstrated synaptosomal-associated protein 25 immunoreactivity throughout the neurons, including the cell bodies, neurites and growth cones. Using electron microscopy, gold signals immunoreactive for synaptosomal-associated protein 25 were identified diffusely in the cytoplasm of the growth cones. In contrast, in PC-12 cells, a large number of gold signals were localized on the plasma membranes. High levels of signal were also found in the cytoplasm in the central region of the growth cones. We also confirmed that botulinum neurotoxin A treatment reduced neurite extension by about 50%. However, both in dorsal root ganglion neurons and in PC-12 cells we found no differences in the ultrastructure nor in the localization of synaptosomal-associated protein 25 between growth cones with and without toxin treatment. These results indicate that cleavage of synaptosomal-associated protein 25 inhibits growth cone extension in a manner different than that of syntaxin cleavage. The results of this study suggest the possibility that synaptosomal-associated protein 25 is involved in growth cone extension through a process independent of vesicle fusion.

[Reoperative off-pump subclavian-coronary artery bypass grafting in an elderly patient with left internal thoracic artery stenosis]

A 80-year-old Japanese female was diagnosed to have angina pectoris and admitted to our hospital. She had been operated on with mitral valve replacement and coronary artery bypass grafting to right and circumflex coronary artery 4 years before. The coronary angiogram showed significant stenosis with severe calcification in the left anterior descending coronary artery, and it was unsuitable for catheter intervention. The patient also had stenotic left internal thoracic artery and multiple cerebral infarction, but successful off-pump subclavian-coronary artery bypass grafting using saphenous vein graft through small thoracotomy was performed without new neurological deficit. This procedure is useful for patients with left internal thoracic artery unsuitable for MIDCABG, due to quality, size, or injury during preparation.

Relationship between chromosomal aberrations by fluorescence in situ hybridization and DNA ploidy by cytofluorometry in osteosarcoma

An analysis of the chromosomal aberrations and DNA ploidy in the interphase nuclei of seven human osteosacomas was preformed by double-target fluorescence in situ hybridization (FISH) and DNA cytofluorometry. The FISH study of the numerical aberrations in chromosomes 1 and 17 or the structural aberrations in chromosome arm 1p or 17p was carried out by using four locus specific DNA markers, with one pair consisting of 1q12 and 1p36 and the other pair consisting of the 17 cemtromere and 17p13.3. There was no significant differences in the percentage of deletions in chromosome 1 and 17 between osteosarcomas and normal tissues. However, all seven tumors studied had extra copies. Cells with more than three probe signals were regarded as having chromosome polysomy. The percentage of polysomy of chromosome 1 was 20.0-64.0%, and chromosome 17 was 28.0-60.0%. The DNA ploidy patterns of hyperdiploid cells showing a greater DNA content than diploid cells were obtained by DNA cytoflurometry. Five of the seven tumors were non-diploid, and the remaining two were diploid. The percentage of polysomy was correlated with the percentage of hyperdiploid cells in each tumor. Thus, these findings indicated that the DNA ploidy changes were closely correlated with aberrations in the chromosome copy number in osteosarcomas.

DNA ploidy alterations detected during dedifferentiation of periosteal chondrosarcoma

DNA ploidy of a case with dedifferentiated periosteal chondrosarcoma was analyzed by DNA cytofluorometry. The diagnosis of primary periosteal chondrosarcoma was made on the basis of the radiographic and histological findings. At 4 years after marginal resection, the tumor recurred locally and metastasized to various organs. The patient died of disease 2 years later. Histologically, there were two components, chondrosarcoma and malignant fibrous histiocytoma, in the recurrent and metastatic tumors. DNA ploidy analysis of multiple samples revealed that the primary lesion was composed of many diploid cells with some tetraploid and octaploid cells, whereas in the dedifferentiated area, there were many aneuploid cells which were not recognized in any area of the primary tumors. This case illustrated that DNA ploidy alteration of euploidy to aneuploidy is closely correlated with the process of dedifferentiation in chondrosarcoma.