Relationship between histologic grade and cytofluorometric cellular DNA and RNA content in primary bone tumors

The diagnosis and grading of bone tumors remains a challenging problem. We studied the relationship between histologic grade and cytofluorometric cellular DNA and RNA content in 108 primary bone tumors. The data included DNA ploidy, mean DNA content (MDC), S-phase fraction (SPF), mean RNA content (MRC) and RNA/DNA ratio (RDR; MRC/MDC) which represents the RNA content normalized for the DNA content. Benign tumors had a diploid stem line with low MDC (mean; 1.04), low SPF (0.9), high MRC (2.41) and high RDR (2.31). Giant cell tumors of bone, which are locally aggressive benign tumors, showed diploidy with relatively higher MDC (1.07, p < 0.01) and SPF (2.6, p < 0.01) and lower MRC (1.81, p < 0.01) and RDR (1.69, p < 0.01). Similar results were obtained in low-grade sarcomas. In high-grade sarcomas, the data depended on the histologic findings. Pleomorphic sarcomas such as osteosarcomas revealed aneuploidy with remarkably higher MDC (1.70 in osteosarcomas, p < 0.01) and SPF (6.5, p < 0.01), but lower RDR (1.70, p < 0.01). In contrast, small cell sarcomas, such as Ewing's sarcomas, showed diploidy with low MDC (1.11 in Ewing's sarcomas, N.S.) and SPF (2.5, p < 0.01) and extremely low RDR (1.34, p < 0.01). The RDR value was higher in well-differentiated tumors than in primitive tumors, rendering it useful in grading bone tumors with a diploid stem line. By combining the RDR value with the MDC value, 96% of diploid sarcomas could be distinguished from benign tumors. These results indicate that cellular DNA and RNA content analysis may be of value in assessing the malignant potential of diploid as well as aneuploid bone sarcomas.

Expression of transduced HSP70 gene protects chondrocytes from stress

OBJECTIVE

To investigate the efficacy of adenovirus vector mediated transduction of heat shock protein 70 (HSP70) gene to human chondrocyte-like cell (HCS-2/8) against heat stress.

METHODS

Two adenovirus vectors that contain wild-type (AxSHEwt) or mutant-type (AxSHEmt) HSP70 gene, and that are regulated by SRalpha promoter, were constructed. The mutant-type lacks the area that expresses stress durability. One of the 2 adenovirus vectors was added to the cultures of human chondrocyte-like cells (HCS-2/8). Heat stress (48 degrees C) was applied to the transduced cells for 2 h, and the efficacy of adenovirus vector mediated transduction of HSP70 gene against heat stress in the chondrocytes was investigated using alamar blue assay and MTT assay.

RESULTS

Absorbance levels at 48 degrees C were 300.3 +/- 51.9 and 1.173 +/- 0.011 in the controls, 278.5 + 33.8 and 1.217 +/- 0.018 in the AxSHEmt transduced cells, and 349 +/- 14.7 and 1.371 +/- 0.033 in the AxSHEwt transduced cells. The level in the AxSHEwt transduced cells was significantly higher than in the other 2 groups (p < 0.05). With 37 degrees C treatment, no significant difference was observed.

CONCLUSION

Chondrocytes to which HSP70 gene was transduced had a significantly higher metabolic activity and viability under heat stress.

Dialysis-related amyloidosis of the heart in long-term hemodialysis patients

BACKGROUND

Dialysis-related amyloidosis (DRA) predominantly occurs in the osteoarticular structures, but it also systemically appears in the extra-articular tissues as well. However, the pathological characteristics of DRA in the hearts of hemodialysis (HD) patients have rarely been reported.

METHODS

We studied the pathological characteristics of DRA in the hearts of 18 HD patients, including its relationship to calcification. Furthermore, we studied the immunohistochemical localization of advanced glycation end products (AGEs) using monoclonal anti-imidazolone and anti-Nepsilon-(carboxymethyl)lysine (CML) antibodies.

RESULTS

beta2-microglobulin (beta2m) amyloid deposits were detected in the hearts of seven patients who had undergone HD for more than 10 years. beta2m amyloid deposits in the left atrium were localized in the endocardium, the myocardium, and the walls of small blood vessels, whereas in the left ventricle, they were localized only in the walls of small blood vessels. The extent and prevalence of DRA in the heart were severe in the patients on HD for more than 15 years. Most calcification areas near mitral valve were dotted with beta2m amyloid deposits, while diffuse fine calcification was localized within the beta2m amyloid tissues in some cases. Imidazolone and CML were localized not only in massive beta2m amyloid deposits, but also in cardiac myocytes.

CONCLUSION

DRAs were localized extensively in the hearts of long-term HD patients. A strong affinity was observed between beta2m amyloid deposits and calcification.

Acridine orange induces binucleation in chondrocytes

OBJECTIVE

Although it is well known that binuclear cells commonly appear among the chondrocytes of normal cartilages as well as among neoplastic chondrocytes of chondrosarcomas, the mechanism of binucleation is still unclear. Therefore, this study was undertaken to clarify the mechanism of binucleation in chondrocytes, using primary culture cells of growth plate cartilage.

DESIGN

These chondrocytes were exposed to acridine orange (AO) which is a fluorescent dye for differentiating certain DNAs and RNAs in nuclei and cytoplasm, and which inhibits mitosis. After exposure to 0.5 microg/ml AO, for 0, 6, 24, 48, and 96 h, the following parameters were investigated: (1) cell growth rate (GR); (2) frequency of hyperdiploid cells (%HDC) by DNA cytofluorometry; (3) mitotic index (MI); (4) BrdU labeling index (LI); (5) frequency of binuclear cells (%BNC).

RESULTS

Compared with the control cells, which were cultured in AO-free medium, the GR was remarkably inhibited at 24 h. MI was also decreased from 6 to 24 h, and LI decreased at 48 h. However, these parameters were recovered at 96 h. The %HDC was increased from 6 to 96 h, and the %BNC was also increased to a maximum of six times that of the control cells at 96 h.

DISCUSSION

These results suggested that the binuclear cells observed among the cultured chondrocytes may be formed from G2 arrested cells by amitotic nuclear division, but not by mitosis without cytoplasmic division or cell fusion.

Oral administration of 1 alpha hydroxyvitamin D3 inhibits tumor growth and metastasis of a murine osteosarcoma model

We studied the effect of oral administration of 1 alpha hydroxyvitamin D3 (1-D3) on the growth and metastatic ability of Dunn murine osteosarcoma model. A solution of 1-D3 or vehicle alone was administered daily for 2 weeks to tumor-bearing mice using an esophageal tube and tumor size was serially monitored. In 1-D3-treated mice, the growth of Dunn osteosarcoma was significantly suppressed in a dose-dependent manner. Histologically, tumor cells in the control mice proliferated in marginal regions of the tumor with wide central necrosis, whereas in the 1-D3-treated mice, tumor cells were distributed as scattered islands among extensive necrotic tissue. The mean tumor necrosis area was 55.7% in the control tumors and 94.6% in 1-D3-treated tumors (p < 0.001). There were no substantial differences in the cytofluorometric cell cycle distribution or the histological mitotic index between control and 1-D3-treated tumors. When 1-D3 was administered to mice from 2 days before to 2 weeks after transplantation of the tumor, there were significantly fewer metastatic foci in the lungs in 1-D3-treated mice than in control mice. We also tested the effect of coadministration of 1-D3 and doxorubicin on the growth of Dunn osteosarcoma and found that these two drugs act additively to suppress tumor growth. These results indicated that 1-D3 given orally inhibits tumor growth and metastases in a Dunn osteosarcoma model. Although the mechanism remains unknown, oral administration of 1-D3 might be promising as a new method of treating human osteosarcoma.

Bilateral isolated tarsal navicular fracture dislocation: a case report

Fracture-dislocation of the tarsal navicular is rare injury because of strong ligamentous support on both its plantar and dorsal sides. The authors report a case of a twenty-five-year-old man who sustained bilateral isolated tarsal navicular fracture-dislocations, treated by open reduction and internal fixation combined with external fixation. The patient reported no difficulty in activities of daily living, but T1-weighted magnetic resonance imaging showed a low-intensity area in right tarsal navicular, raising suspicion of osteonecrosis when he was last seen two year three months after operation.

Drug resistance modification using pulsing electromagnetic field stimulation for multidrug resistant mouse osteosarcoma cell line

Multidrug resistance (MDR) is one of the major problems in osteosarcoma chemotherapy. Therefore, methods of overcoming MDR are urgently needed. In this study, we investigated the effects of pulsing electromagnetic field stimulation (PEMFs) on a MDR murine osteosarcoma cell line which strongly expresses P-glycoprotein (P-gp). To assess the reversal effects of PEMFs on doxorubicin (DOX) resistance, MTT assay was applied. Viable cells were assessed by the trypan blue exclusion test. Fluorescence intensity of DOX binding to nuclear DNA of each cell was measured using a cytofluorometer. Changes in P-gp expression in each cell were detected by the indirect immunofluorescence method using an antibody to Pgp. PEMFs increased DOX binding ability to nuclear DNA and inhibited cell growth, although it had no significant effect on P-gp expression. These findings indicated that PEMFs reversed the DOX resistance of the MOS/ADR1 cells by inhibiting P-gp function. The results suggested that PEMFs may be useful as a local treatment for MDR osteosarcoma.

Characteristics of proton NMR T(2) relaxation of water in the normal and regenerating tendon

The molecular behavior of water in normal and regenerating tendons was analyzed using the transverse relaxation time (T(2)) measured by spin-echo proton nuclear magnetic resonance ((1)H-NMR) spectroscopy at 2.34 T (25 degrees C). A section of the Achilles tendon was dissected from an anesthetized Japanese white rabbit, and its longitudinal axis was oriented at 0, 35, 54.7, 75, and 90 degrees to the static magnetic field. In the normal tendon, the T(2) relaxation of water presented biexponential relaxation and anisotropy in both the long T(2) (5.41 to 6.21 ms) and short T(2) (0.41 to 1.43 ms) components, in which the greatest values were obtained at 54.7 degrees. However, the range of the anisotropy was much narrower than we expected from the (1)H dipolar interaction of water bound to the collagen fibers in the tendon. The apparent fractions of water proton density also varied with orientation: the fraction of the longer T(2) components was at its maximum at 54.7 degrees. These results suggest that a simple two-compartment model could not be applicable to orientational dependency of the T(2) value of the tendon, and the well ordered water in the short T(2) relaxation component may show an elongated T(2) relaxation time that falls in the range of the long T(2) relaxation component at 54.7 degrees. This hypothesis can explain both the narrower range of the T(2) relaxation time and the orientational dependency on the apparent fraction of (1)H density. Regenerating processes of the Achilles tendon were followed for 18 weeks by analyzing the T(2) relaxation time. There is only a long T(2) relaxation time component (21.8 to 28.0 ms) up to 3 weeks after transection. Biexponential relaxation is revealed at 6 weeks and thereafter, whereby (i) the T(2) relaxation times become shorter, (ii) there is anisotropy in the short and long T(2) values, and (iii) the orientational dependency of the apparent fraction of water proton density becomes evident with maturation of the regenerating tendon. From these results, the (1)H T(2) relaxation time of water might be used to monitor the healing process of collagen structures of the tendon non-invasively.

Carpal tunnel syndrome in patients on long-term haemodialysis

The purpose of this study was to describe the pathophysiology of carpal tunnel syndrome (CTS) in patients on long-term haemodialysis. We examined 110 patients, who had been having haemodialysis for chronic renal failure and had CTS, to clarify the clinical features and electrophysiological changes in peripheral nerves. There was a significant correlation between the incidence of CTS and the duration of haemodialysis. Compared with idiopathic CTS, CTS caused by long-term haemodialysis had relatively limited postoperative improvement. Symptoms recurred postoperatively in 11 patients (19%) of those with CTS caused by long-term haemodialysis. Electrophysiological measurements of sensory nerve conduction velocity showed that it was slower in distal segments of the median nerve in patients on haemodialysis compared with normal volunteers. Nerve conduction velocity in the carpal tunnel was significantly delayed (p < 0.05) in the patients with CTS on long-term haemodialysis. N9-13 interpeak latencies were significantly longer (p < 0.05) in subjects who had had haemodialysis for at least 10 years. All the patients with advanced destructive spondyloarthropathy had longer N9-13 interpeak latency. These results suggest that CTS in patients on long-term haemodialysis has its basis in neuropathy. The clinical course of CTS in these patients is different from that of patients with idiopathic CTS, because the neuropathy involves not only the carpal tunnel region, but also the proximal part of the median nerve both diffusely and progressively.

Reconstruction of the anterior cruciate ligament using a double bundle

We developed a reconstruction technique for the anterior cruciate ligament using a double bundle that is the combination of bone-tendon-bone (BTB) from the patellar tendon and semitendinosus tendon (ST). BTB is fixed in the tunnels produced on the isometric points on the tibia and femur. ST is fixed on the tibial tunnel through the same route as the BTB, but on the femur, through the over-the-top route, which is located posterolateral to the femoral tunnel. Use of this double bundle realizes a physiologically more durable reconstruction because BTB corresponds to the anteromedial bundle of the ACL and ST corresponds to the posterolateral bundle, and these produce 2 different tension patterns within the bundle. This technique is also applicable to revision surgeries for patients with an extended bone loss on the tibia.

Bilateral epiphyseal fractures of the proximal tibia within a six-month interval: a case report

An epiphyseal fracture commonly results from avulsion of the epiphysis by traction through the attached ligaments. A fracture of the proximal tibial epiphysis is, therefore, a rare injury because of the absence of collateral ligament attachments. Most proximal tibial epiphyseal injuries occur as avulsion fractures of the tibial tubercle; Salter-Harris Types I or II injuries involving pressure epiphyses are rare. In the current case of a thirteen-year-old boy, the proximal tibial epiphyseal injuries in both knees occurred during quadriceps contraction in the absence of violent trauma, and there was a six-month interval between the two injuries.

Development of bone canaliculi during bone repair

We recently found that silver impregnation staining with protargol (silver protein), that is, a modified Bodian method, is useful for histologically identifying the details of bone canaliculi structure, using thin sections of decalcified bone tissues. With this staining method, we conducted the present study to assess the development of bone canaliculi during the process of intramembranous ossification using a fracture-like stimulation model of the rat femur. After making a drill-hole in the cortex of the rat femur, decalcified thin sections were obtained after 3, 5, 7, and 14 days by the standard paraffin-embedding procedure. Silver staining for bone canaliculi was performed using our previously reported technique. The results showed that woven bone covered the fracture surface of the cortex after 5 days, then immature lamellar bone attached to the woven bone after 7 days, and finally the lamellar bone matured and became thick with appositional growth after 14 days. The osteocytes in the woven bone appeared at an early stage of bone repair and developed a few canaliculi that were short and irregularly distributed in the osteoid matrix, while the osteocytes in the lamellar bone at a late stage formed many bone canaliculi that were long and regularly distributed in mature bone matrix. Therefore, we concluded that woven bone osteocytes may be necessary for induction of the lamellar bone osteocytes followed by active appositional growth of the lamellar bone at the early stage of bone repair, and also that both bone tissues could be clearly distinguished from one another based on the pattern of development of bone canaliculi by the osteocytes, as seen with the use of our sensitive staining method.

DNA cytofluorometric analysis of benign and malignant nerve sheath tumors

The present study was undertaken to examine the ploidy patterns of benign and malignant nerve sheath tumors using PI-DNA cytofluorometry and to clarify the relationship between the ploidy patterns and pathological findings for these lesions. The benign nerve sheath tumors (schwannomas and neurofibromas) were found to be dipolid or to be euploid-polyploidization, with a few DNA synthetic cells. The number of polyploid cells increased with increase in the frequency of cells with large and atypical nuclei in histology, regardless of the natures of cellular arrangements. Malignant schwannomas were composed of many polyploid and aneuploid cells with DNA synthetic cells, indicating their active cell proliferation. Thus, benign nerve sheath tumors exhibited low-proliferative ploidy patterns that were clearly different from those of malignant nerve sheath tumors. As Takeshita has already stated, it is difficult to ascertain why some of the neurogenic tumors show euploid-polyploidization (19). Further investigations will be needed in this direction. Finally, it is clear from the results of this study that the cytofluorometric analysis mentioned above is useful for assessing malignancy and that it may be useful for predicting prognosis of nerve sheath tumors.

Ultrastructural characteristics and synaptophysin immunohistochemistry of regenerating nerve growth cones following traumatic injury to rat peripheral nerve

Growth cones of regenerating nerves, following crush injury to the rat peripheral nerve system, were studied by electron microscopy and synaptophysin. Localization in the growth cones was revealed by immunohistochemistry at the ultrastructural level. Many regenerating growth cones grew along the Schwann-cell basal laminae tubes at the crushed site. These cones revealed an abundance of organelles, such as heterogenous vesicles and many mitochondria, and a scarcity of cytoskeletons, including microtubules and neurofilaments in the cytoplasm. The periphery of the growth cones (corresponding to the lamellipodia or filopodia of cultured neurons) contained rich electron-dense filamentous materials. Cellular protrusions, such as filopodia, were rarely seen. These growth cones exhibited intense immunoreactivity for synaptophysin by light microscopy. Immunoelectron microscopy demonstrated that immunoreactivity was distributed diffusely in the cytoplasm.

Estimation of cervical cord dysfunction by somatosensory evoked potentials

The purpose of this study was to examine the relationship of abnormal short-latency somatosensory evoked potentials (SSEPs) recorded by a noncephalic reference montage with clinical variables in cervical myelopathy patients and to reexamine the diagnostic utility of SSEPs in such patients. We studied cervical SSEPs elicited by stimulating the median and ulnar nerves in 87 patients. Our grade classification of spinal N13, which is based on the normal limits of latencies or amplitudes, corresponded well with the clinical variables and is of value when trying to localize the cervical lesion segmentally. The N9-P14 interpeak latency in response to ulnar nerve stimulation correlated well with lower extremity function (r = -0.440, P <0.0001). We suggest a combined assessment of N13 amplitude, and N9-N13 and N9-P14 interpeak latencies to estimate dorsal column and dorsal horn function separately in patients with cervical myelopathy.

Binuclear cells induced by acridine orange in giant cell tumor of bone

We have recently found the presence of many binuclear cells among isolated and smeared cells in giant cell tumor of the bone (GCT). These binuclear cells are possibly associated with the formation of multinuclear cells. Therefore, this study was undertaken to clarify the mechanism of binucleation in GCT, using primary culture cells exposed to acridine orange (AO) which is a fluorescent vital staining dye for the cytoplasm and nucleus and which inhibits mitosis. The cells were isolated from explants of fresh tumor materials obtained from two GCT patients (GCT1 and GCT2). These cells were cultured in Dulbecco's modified Eagle medium (DMEM) with 10% Fetal calf serum (FCS). After exposure to 0.5 microgram/ml AO, for 0, 6, 24, 48, 96 and 144 hours the following parameters were investigated: 1) cell growth rate (GR); 2) frequency of hyperdiploid cells (%HDC) by DNA cytofluorometry; 3) mitotic index (MI); 4) BrdU labeling index (LI); 5) frequency of binuclear cells (%BNC). Compared to the control cells which were cultured in AO-free medium, the GR of both GCT cells exposed to AO was remarkably inhibited. The MI was 0 from 24 to 144 hours. The %HDC was increased at 24 hours and was maintained high until 144 hours. The LI was temporarily increased at 6 hours, but was decreased at 48 hours. The %BNC was gradually increased. AO inhibited DNA synthesis and cell mitotic activity in cultured GCT cells and it finally caused inhibition of cell growth. However, the frequencies of G2 arrest cells and binuclear cells were increased. These results suggested that the binuclear cells in GCT may be formed from G2 arrest cells by amitotic nuclear division, but not by mitosis without cytoplasmic division, or by cell fusion.

Assessment of chemosensitivity in patients with malignant bone and soft tissue tumors using thallium-201 scintigraphy and doxorubicin binding assay

This study was performed to compare the accumulation of thallium (Tl)-201 which is correlated with malignancy and the doxorubicin binding ability, which is correlated with chemosensitivity, in nine patients who received preoperative chemotherapy with doxorubicin and cisplatin. Tl-201 scintigraphy was performed at 15 minutes (early image) and 3 hours (delayed image) after injection of 111 MBq of Tl-201. The change of degree of the radionuclide uptake between the early and delayed images was evaluated before and after preoperative chemotherapy. The doxorubicin binding ability (%DB) to nuclear DNA in living tumor cells isolated from biopsy materials was assessed by doxorubicin binding assay. The histologic response to preoperative chemotherapy was evaluated by the percentage of tumor necrosis. Before preoperative chemotherapy no changes of Tl-201 uptake between the early and delayed images was detected in any tumors. Five patients, who had no change of Tl-201 uptake after preoperative chemotherapy, showed a poor histologic response and had a %DB ranging from 10% to 70% (mean: 36.0%). The other four patients, who had a %DB greater than 90%, showed a good histologic response. All of these four patients had decreased Tl-201 uptake after preoperative chemotherapy. This study demonstrated that doxorubicin binding assay and midcourse Tl-201 scintigraphy are useful methods to assess the response to chemotherapy early in malignant bone and soft tissue tumors.

Case report of secondary chondrosarcoma showing spontaneous regression after frequent recurrences

We report a case of secondary chondrosarcoma arising in the ilium showing spontaneous regression after frequent local tumor recurrences followed by multiple surgeries of marginal or intralesional excision. The patient was a 16-year-old boy who had been diagnosed as having multiple exostosis from 9 years of age. He experienced an increasing abdominal tumor mass that formed a huge tumor. Although marginal resection of the tumor was attempted, intraperitoneal dissemination was caused by rupture of the tumor capsule and the peritoneum, as a result of severe tumor adhesion to the peritoneum. During the 5 years after the initial operation, local recurrences occurred seven times in various areas of the intra- or retro-peritoneum and marginal or intralesional excision was performed every time for a total of 14 tumors. However, since the seventh operation, the patient has had no evidence of recurrence or metastasis of the disease for more than 10 years. Therefore, we considered that the cancer might have spontaneously regressed.

Nerve contact with muscle component in neuromuscular hamartoma

Neuromuscular hamartoma is a very rare soft tissue tumor, of which only 20 cases have been reported previously. None of these reports has described the relation between hamartomatous skeletal muscle and nerve fibers in the tumor. We experienced a patient with neuromuscular hamartoma arising at the brachial plexus. In this tumor, the localization of synaptophysin (SYP), S-100 protein (SP), neuron-specific enolase (NSE) neurofilament protein (NFP) and myoglobin (MG) was immunohistochemically detected. The results showed that SYP and MG were diffusely localized in the hamartomatous muscle fibers, SP in the schwann cells, and NSE and NFP in the axons of the hamartomatous nerve. Therefore, it is suggested that in the neuromuscular hamartoma, the structure of the neuromuscular junction may be similar to that in the motor end-plate of the normal muscle, but it may not be functional, because the hamartomatous muscles could not contract by nerve stimulation.

Radial magnetic resonance imaging and pathological findings of acetabular labrum in dysplastic hips

Radial MRI findings and pathological changes were comparatively examined in the acetabular labrum of 11 hips of 11 patients, who underwent total hip arthroplasty for osteoarthritis due to acetabular dysplasia. Diffuse high signal pattern on the radial MR images corresponded to histological degeneration of the labrum. High signal pattern which was equivalent to the synovial fluid, showed an intralabral tear. In the obscure areas of MR images, severe impairment of the labrum such as rupture, detachment, and displacement were found.

Fluorovisualization effect of acridine orange on mouse osteosarcoma

If the localization of musculoskeletal sarcomas could be visualized during surgery, it would be possible to completely resect the tumor with minimum damage to normal tissues and the patients could retain a functional limb. Therefore, we conducted the present study to clarify the usefulness of acridine orange (AO) for fluorovisualization of tumors using a mouse osteosarcoma model. At 2 hours after injection of 10 mg/kg AO to mice inoculated with MOS mouse osteosarcoma cells, fluorovisualization of mouse osteosarcoma reached the maximum level. Even a 1-mm-diameter lesion of pulmonary metastasis was visualized. The results suggested that AO may be useful for specific fluorovisualization of human osteosarcomas during surgery.