Angiography for assessment of preoperative chemotherapy in musculoskeletal sarcomas

Eleven abnormal findings of digital subtraction angiography were analyzed in 25 patients with bone sarcoma and in 23 patients with soft tissue sarcoma. The relation between digital subtraction angiographic findings and the histologic effect of chemotherapy was evaluated. Digital subtraction angiography was performed with the patient under local anesthesia with the Seldinger technique, using an ADVANT X unit. Contrast medium was injected at a rate of 4 to 6 ml per second, with the usual single bolus dose of approximately 6 to 8 ml. Eleven abnormal findings included tumor stain, hypervascularity, arterial distortion, vascular stretch, arterial dilatation, arteriovenous shunt, arterial encasement, occlusion, blood pool, caliber with irregular wall, and dilatation of draining vein. Each finding after preoperative chemotherapy was compared with that before chemotherapy and divided into three grades; Grade 1, not effective; Grade 2, effective; and Grade 3, very effective. Angiographic Grades 2 and 3 were defined as responders. The histologic effect was examined and scored according to the modified classification proposed by Huvos. Histologic Grades 1 and 2 were classified as nonresponders and Grades 3 and 4 as good responders. In bone sarcomas, hypervascularity and tumor stain were seen in all patients. In soft tissue sarcomas, tumor stain was shown in all 23 patients and hypervascularity was seen in 21 patients. Tumor stain, hypervascularity, vascular stretch, and arterial encasement were correlated closely with histologic findings and showed an accuracy equal to or greater than 70%. When these four findings changed to angiographic Grade 3 after preoperative chemotherapy, 90% of patients had good histologic outcome.

Clinical experience of left ventricular assist systems at the Heart Institute of Japan

The main indications for left ventricular assist system (LVAS) support are postcardiotomy ventricular failure as temporary circulatory support and end-stage cardiomyopathy as chronic circulatory support. To clarify the efficacy of LVAS support, we assessed the clinical outcome of a pneumatic LVAS and an electromagnetic LVAS for patients with severe ventricular failure. As of March 1998, 5 patients with postcardiotomy ventricular failure had received the pneumatic LVAS support, and 2 other patients with end-stage idiopathic cardiomyopathy had undergone implantation of the electromagnetic LVAS. The drive control of the LVAS was mainly counterpulsation in the diastole of the native heart. In the 5 postcardiotomy patients, the duration of pneumatic LVAS support ranged from 30 to 312 h (mean, 109.2). All 3 patients with more than 72 h support were successfully weaned, and 2 of them survived. The other 2 patients with cardiogenic shock and less than 36 h support could not be weaned from the LVAS. In the 2 cardiomyopathy patients, 1 patient was well maintained by the electromagnetic LVAS support and underwent successful heart transplantation 7 months later. The other patient has been chronically supported by the LVAS for 2 months and is doing well so far. These results suggest that selective application of the pneumatic LVAS as a temporary support and the electromagnetic LVAS as a chronic support might be appropriate for maximizing the effectiveness of LVAS treatment for profound cardiac failure.

High complication rate of reconstruction using Ilizarov bone transport method in patients with bone sarcomas

We performed five reconstructions by bone transport in patients with bone sarcoma: three osteosarcomas, one Ewing's sarcoma and one chondrosarcoma. Four sarcomas were in the distal femur and one in the shaft of the tibia. Four patients received multidrug chemotherapy. The average length of the skeletal defect after tumour resection was 17 (range 10-25) cm. All patients underwent double elongation from both proximal and distal sites of the bone defect. The average follow-up period was 48 (range 40-66) months, and the average duration of external fixation was 32 months (range 579-1340 days). In one case, bone formation was satisfactory, but in the other cases, it was poor and slow. The average treatment index was 95 (range 53-191) days per 1 cm of elongation. In one case, the bone fragment disappeared during the bone transport. In one case, the end of the bone protruded from the skin, and osteomyelitis set in. This patient underwent above-knee amputation due to failure of infection control. Three patients suffered talipes equinus. One patient died of pulmonary metastasis. Two patients had fair and three had poor function. This method is not recommended for patients with bone sarcoma who may have a poor prognosis, as it has an unacceptably high complication rate.

A rotating-hinge knee replacement for malignant tumors of the femur and tibia

We evaluated the 2- to 7-year results of a rotating-hinge knee replacement after excision of malignant tumors of the knee joint. There were 25 distal femoral and 7 proximal tibial replacements. The 5-year prosthetic survival for distal femoral replacements was 88%, compared with 58% for proximal tibial replacements. Seven patients underwent prosthetic exchange: 1 for aseptic loosening, 2 for wound slough and perioperative infection, and 4 for articulating component failure. One patient underwent above-knee amputation owing to skin necrosis. The median functional scores at the latest follow-up were 27 by the International Society of Limb Salvage evaluation system and 80 by the Hospital for Special Surgery Knee Score system. This implant is a promising choice for joint reconstruction after excision of tumors at the knee joint.

Relationship between magnitude of resection, complication, and prosthetic survival after prosthetic knee reconstructions for distal femoral tumors

BACKGROUND AND OBJECTIVES

Limb-sparing surgery has become the preferred surgical treatment of malignant bone tumors. The objective of this study was to evaluate factors that influence the morbidity and outcome of prosthetic knee replacement after resection of malignant tumors of the distal femur.

METHODS

Eighty-two patients who had a resection of malignant tumor of the distal femur and implantation of a segmental knee prosthesis (minimum follow-up, 2 years) were retrospectively reviewed.

RESULTS

Twenty-nine patients (35%) underwent 32 prosthetic revisions, 6 from perioperative wound complications, 13 from aseptic loosening, and 13 from other complications. The 3-, 5-, and 10-year Kaplan-Meier prosthetic survival rates were 82%, 71%, and 50%, respectively. On univariate analysis, patients who had more than 40% resection of the distal femur (P = 0.010) and those who had all their vasti muscles resected (P = 0.011) had significantly worse prosthetic survivals than the others. On multivariate analysis, resection of more than 40% of the distal femur was a significant negative prognostic factor for prosthetic survival (P = 0.017). Aseptic loosening was the primary cause of late prosthetic failure. Differences in the magnitude of resection influenced prosthetic survivorship more than prosthetic design.

CONCLUSIONS

In the distal femoral endoprosthetic replacement, higher short- and long-term complications were found after extensive resections. Aseptic loosening was the primary cause of prosthetic failure.

Studies on the structures and antigenic properties of rabies virus glycoprotein analogues produced in yeast cells

We investigated two forms (designated as yGI and yGII) of rabies virus glycoprotein (G) analogues produced in the G cDNA-transfected yeast cells. Molecular weights of yGI and yGII were estimated as 66 and 56 kDa, respectively, according to their relative mobility in SDS-PAGE. Although being produced in large amounts, yGI was present mostly in insoluble forms and hardly extractable with non-ionic detergents. The yGI reacted with polyclonal anti-G antibodies, but did not react with our conformational epitope-specific anti-G monoclonal antibodies (G-MAbs). No protective immunity was induced by yGI in guinea pigs nor in mice. On the other hand, yGII was Triton-soluble, but was only small in amount (at most 1% of total G proteins) and was shown to lack the cytoplasmic domain. The yGII, however, reacted with the G-MAbs and induced protective immunity in guinea pigs as well. When the G-cDNA was expressed in animal cells in culture, a single form (about 66 kDa) of G protein was produced, which displayed similar behaviors as seen in its reactivity with the MAbs and intracellular distribution as seen in the virus-infected cells. These results suggest that most G protein molecules were not processed normally in yeast cells, resulting in abnormal folding and multimer formation, while only a small fraction were occasionally folded normally to have conformational epitopes but were mostly deprived of the C-terminal portion.

Studies on the rabies virus RNA polymerase: 2. Possible relationships between the two forms of the non-catalytic subunit (P protein)

We investigated the relationship between the two forms of rabies virus P protein, a non-catalytic subunit of rabies virus RNA polymerase. The two displayed different electrophoretic mobilities as 37- and 40-kDa polypeptides, hence termed as p37 and p40, respectively. Double labeling experiments with [3H]leucine and [32P]orthophosphate demonstrated that p40 was much more phosphorylated than p37. Treatment of the virion proteins with alkaline phosphatase eliminated only p40, and not 37-kDa polypeptide. The p37 was a major product of the P gene, and was accumulated in the infected cell and incorporated into the virion. On the other hand, p40 was apparently detected only in the virion, and little detected in the cells. Treatment of infected cells with okadaic acid, however, resulted in significant accumulation of p40 in the cell, suggesting that p40 was continuously produced in the cell but dephosphorylated quickly. We detected both 37- and 40-kDa products in P cDNA-transfected animal cells, while only a 37-kDa product was produced in Escherichia coli. Incubation of 37-kDa products from E. coli with the lysates of animal cells in vitro resulted in the production of a 40-kDa product, which was also shown to be suppressed by the heparin. From these results, it is suggested that p40 is produced by the hyperphosphorylation of a 37-kDa polypeptide, which depends on certain heparin-sensitive cellular enzyme(s) and occurs even in the absence of the other viral gene products, and that p40 is reverted quickly to p37 in the infected cells, probably being dependent on some virus-induced factor(s).

Algorithm for the surgical treatment of malignant lesions of the proximal tibia

Complications are common among patients treated for malignant lesions of the proximal tibia and can be difficult to manage. This investigation was a retrospective review of 40 patients treated with total knee replacements after proximal tibial resections. Various reconstructive methods were used to fix the prosthetic stems, reestablish the extensor mechanism, and provide soft tissue coverage. Thirty-one patients had adequate followup to allow for review of prosthetic outcome (means, 78 months; range, 25-193 months). Seven patients died with less than 2 years followup, and two patients had postoperative acute infections treated by early amputation to allow chemotherapy to resume promptly. The overall 5-, 8-, and 12-year event free prostheses survival rates were 62%, 33%, and 16%, respectively. Prognostic factors for prosthetic survival were analyzed (age, gender, type of excision, type of prosthesis, type of fixation, and percent of bone resected). None were statistically significant. Patients with less than 40% of the tibia resected had better prosthetic survival at 5 years. The durability of uncemented stem fixation exceeded that of cemented stems. Expected survival of prostheses after revision was 52% at 8 years. The major cause of limb loss was infection. Failure to reconstruct soft tissues satisfactorily caused most failures. Aggressive multistage management of infection is needed. Prosthetic knee replacement is most suitable for patients with cancers that require chemotherapy and for those patients who have short potential survival.

Evaluation of the effect of preoperative chemotherapy in bone sarcomas. 99mTc-HMDP scintigraphy in 34 cases

We quantitatively analyzed images of 99mTc-HMDP bone scintigraphy in 34 bone sarcomas before and after preoperative chemotherapy. The isotopic uptake was calculated as tumor-to-background ratio (TBR), and the changes in TBR before and after chemotherapy were calculated as the alteration ratio. The histological effect of preoperative chemotherapy was classified in 4 grades, according to Huvos. We defined good scintigraphic responders as cases having decreased uptake after chemotherapy, with an alteration ratio > or = 60%. There was a positive correlation (Rho = 0.76, p < 0.001) between the histological effect and the alteration ratio. Of the 17 good histological responders, 13 showed a good scintigraphic response. The average alteration ratio in 17 cases with good response (68%) was higher than that in 17 cases showing poor response (-9.9%) (p < 0.001). 3 patients with pathologic fractures and 1 with primarily normal uptake showed false negative findings. The sensitivity of this method was 100% and the specificity was 81%.

[Postoperative therapy using human atrial natriuretic peptide in cases of valve replacement]

The effect of hANP (atrial natriuretic peptide) was investigated clinically in 40 patients who underwent isolated valve replacement. Patients were divided into four groups: aortic regurgitation (AR), aortic stenosis (AS), mitral regurgitation (MR) and mitral stenosis (MS). Each group was divided into two subgroups: one was administered hANP after the operation until leaving ICU, and the other was not administered hANP. We measured the levels of hANP and c-GMP and blood pressure, pulmonary artery pressure, central venous pressure and levels of Na, K of urine and blood prcoperatively, immediately postoperatively and 1, 2, 4, 6 hours after operation. First, to examine the relationship between preoperative level of hANP and cardiac function, the relationship between preoperative level of hANP and history of cardiac failure and pulmonary artery wedge pressure (PAWP) were evaluated. Also, we evaluated the relationship between preoperative level of hANP and each dimension on echocardiography. There was a weak statistical relationship between hANP and PAWP (row = 0.39 (p = 0.04) Pearson correlation method) and there was no statistical relationship between hANP and duration of cardiac failure (row = 0.00445 (p = 0.98) Pearson correlation method). Preoperatively Left atrial diameter (LAD) showed a statistical relationship with level of hANP in every group using Spearman correlation method. Other dimensions such as left ventricular diastolic diameter (LVDd) and left ventricular systolic diameter (LVDs) and also fractional shortening (FS) did not show a strong correlation with preoperative level of hANP. Especially, in AS group there was a strong relationship between every dimension and preoperative level of hANP. Only in MS group LAD and the level of hANP were negatively related. This finding suggests that atrial dilatation results in reduction of secretion of hANP in cases of MS on long term follow up. Finally, hNAP therapy was shown to have a continuous diuretic effect, with stable hemodynamics.

Value of thallium-201 scintigraphy in bone and soft tissue tumors

The potential role of thallium-201 (201Tl) scintigraphy in the imaging of various musculoskeletal tumors was investigated in 80 patients. Uptake of 201Tl was observed in 17 (100%) malignant bone tumors, 6 (100%) giant cell tumors, and 2 of 8 (25%) benign bone tumors. Nineteen of 30 malignant soft tissue tumors (63%) were positive for 201Tl scintigraphy, while 2 of 14 benign soft tissue tumors (14%) yielded positive results. None of 6 liposarcomas were visualized by 201Tl scintigraphy. There was no 201Tl uptake in the tissues of 5 non-tumorous conditions. Ten patients with osteosarcoma were evaluated by 201Tl scintigraphy both pre- and post-chemotherapy. There was a significant correlation between changes in tumor-to-normal count ratio and percent necrosis of the resected tumor. The mean decrease in tumor-to-normal count ratio was 71% for patients with >/=90% tumor necrosis and 26% for those with <90% tumor necrosis. Serial 201Tl scintigraphy, with quantitative analysis of alterations in 201Tl uptake, may provide a quantitative and objective measure of the effect of preoperative chemotherapy in patients with malignant bone tumors.

A new human chondrosarcoma cell line (OUMS-27) that maintains chondrocytic differentiation

A new human chondrosarcoma cell line, OUMS-27, was established. Monolayer cultures consisted of elongated polygonal cells with a doubling time of 41 hr and a plating efficiency of 2.1%. After reaching confluence, the cells continued to slowly proliferate and formed nodule-like structures, which showed metachromasia when stained with toluidine blue, indicating the presence of proteoglycan. The cells in the nodules were round to polygonal in shape, multilayered and surrounded by abundant extracellular matrix. Types I, II and III collagens were identified by Northern blotting and immunostaining. The cells formed colonies (0.1%) in 0.3% soft-agar medium 3 weeks after inoculation. Inoculation of cells into athymic mice resulted in the formation of tumors at the injection site, resembling the original chondrosarcoma. These results demonstrated that OUMS-27 cells expressed a differentiated chondrocytic phenotype. Moreover, OUMS-27 cells had p53-gene mutation. Thus, the OUMS-27 cell line can provide a useful model not only for studies on human chondrocyte but also for basic studies on the diagnosis, treatment and etiology of human chondrosarcoma.

Minimally invasive cardiac surgery in the adult: surgical instruments, equipment, and techniques

To clarify the special instruments and equipment used for minimally invasive cardiac surgery (MICS), we examined the initial experiences with MICS operations with ministernotomy or minithoracotomy at our institution. Fifty adult patients with congenital, valvular, and/or ischemic heart diseases underwent MICS operations, and all surgical procedures were completed without conversion to full sternotomy. The length of the skin incision was about 10 cm or less in all patients. Postoperative recovery was favorable, and the majority of the patients were discharged from the hospital around the end of the second postoperative week. In this series of patients, an oscillating bone saw, lifting type retractor, 2 blade spreader, cannula with a balloon, and right-angled aortic clamp among other items, were very useful for successfully performing various operations with MICS approaches and techniques. The associated results suggest that MICS with ministernotomy or minithoracotomy was feasible using special instruments and equipment and could be encouraged for adult patients with various cardiovascular diseases.

Studies on rabies virus RNA polymerase: 1. cDNA cloning of the catalytic subunit (L protein) of avirulent HEP-flury strain and its expression in animal cells

To investigate the RNA polymerase of rabies virus, we cloned a cDNA of the catalytic subunit (called L protein because of its large molecular size) of the HEP-Flury strain, an avirulent strain obtained by high frequencies of serial embryonated hen egg passages. Nucleotide sequencing showed that the cDNA encodes a long polypeptide of 2,127 amino acids (Mr. 242,938). A comparison of the deduced amino acid sequence with that of other strains (PV and SAD B19) indicated that the sequence was highly conserved, except for several amino acid substitutions which were accumulated in some limited regions. A fragment of the cDNA was used for expression in Escherichia coli (E. coli) to prepare the L antigen for raising the antibodies in rabbits. Immunoprecipitation studies with the rabbit antiserum showed that the polypeptides produced in the L cDNA-transfected COS-7 cells displayed almost the same electrophoretic mobility as that of authentic L protein. Immunofluorescence studies indicated that both L and P (another subunit of RNA polymerase) proteins displayed colocalized distribution with the nucleocapsid antigen (N) in the cytoplasmic inclusion bodies, where envelope proteins (G and M) were absent. On the other hand, expression of the L protein alone did not cause inclusion body-like granular distribution, suggesting that the inclusion body-like accumulation depends on certain interaction(s) with other viral gene products, probably with the ribonucleoproteins comprising the inclusion bodies.

PEX12, the pathogenic gene of group III Zellweger syndrome: cDNA cloning by functional complementation on a CHO cell mutant, patient analysis, and characterization of PEX12p

Rat PEX12 cDNA was isolated by functional complementation of peroxisome deficiency of a mutant CHO cell line, ZP109 (K. Okumoto, A. Bogaki, K. Tateishi, T. Tsukamoto, T. Osumi, N. Shimozawa, Y. Suzuki, T. Orii, and Y. Fujiki, Exp. Cell Res. 233:11-20, 1997), using a transient transfection assay and an ectopic, readily visible marker, green fluorescent protein. This cDNA encodes a 359-amino-acid membrane protein of peroxisomes with two transmembrane segments and a cysteine-rich zinc finger, the RING motif. A stable transformant of ZP109 with the PEX12 was morphologically and biochemically restored for peroxisome biogenesis. Pex12p was shown by expression of bona fide as well as epitope-tagged Pex12p to expose both N- and C-terminal regions to the cytosol. Fibroblasts derived from patients with the peroxisome deficiency Zellweger syndrome of complementation group III (CG-III) were also complemented for peroxisome biogenesis with PEX12. Two unrelated patients of this group manifesting peroxisome deficiency disorders possessed homozygous, inactivating PEX12 mutations: in one, Arg180Thr by one point mutation, and in the other, deletion of two nucleotides in codons for 291Asn and 292Ser, creating an apparently unchanged codon for Asn and a codon 292 for termination. These results indicate that the gene encoding peroxisome assembly factor Pex12p is a pathogenic gene of CG-III peroxisome deficiency. Moreover, truncation and site mutation studies, including patient PEX12 analysis, demonstrated that the cytoplasmically oriented N- and C-terminal parts of Pex12p are essential for biological function.

Preparation and evaluation of micro-porous ethylcellulose capsule as oral sustained-release preparation of theophylline

Micro-porous ethylcellulose (EC) membrane capsules were prepared by dissolving polyvinylalcohol (PVA) particles from membranes which were made of a mixture of EC (a water-insoluble polymer). The pore size was approximately 400 microns. Since the dissolution rate of theophylline from the micro-porous EC membrane capsules was fast, gel-forming polymer, poly(acyclic) acid (Carbomer), was incorporated inside the capsule at 10, 20 or 30 mg. Using test capsules containing 100 microns of theophylline, in vitro dissolution studies were performed. By including Carbomer in capsule formulations, the dissolution rate of theophylline was decreased. However, there were not significant differences in dissolution rates between preparations containing the three different amounts of Carbomer. In vivo evaluation studies using beagle dogs showed that AUC, Cmax and Tmax were inversely proportional to the formulated amount of Carbomer. The capsule containing 20 mg of Carbomer gave plasma theophylline concentrations between 5 and 15 micrograms mL-1, which reflect levels within the therapeutic window. The effect of food intake on the pharmacokinetics of theophylline was also studied with the same capsule. Food increased AUC, Cmax and Tmax, although plasma theophylline levels were maintained within the therapeutic range.

The 21-kDa polypeptide (VAP21) in the rabies virion is a CD99-related host cell protein

In our monoclonal antibody (MAb) stocks prepared against the BHK-21 cell antigens, two (#11875 and 28276) recognized a 21-kDa polypeptide (referred to as VAP21) which is efficiently incorporated into the rabies virion. By using these MAbs, we isolated the cDNA clones that encoded a polypeptide of 144 amino acids from our BHK-21 cell cDNA library. Based on the following evidence, the cDNA was assumed to encode a full-length sequence of VAP21 antigen: i) expression of the cDNA in animal cells resulted in the production of a polypeptide recognized by the two MAbs, and its electrophoretic mobility was the same as that of authentic VAP21 antigen; and ii) immunization with the products from the cDNA-transformed E. coli cells raised specific antibodies in rabbits that recognized a 21-kDa polypeptide in the virion. From the deduced amino acid sequence, it is suggested that the VAP21 antigen has a molecular structure of type-I transmembrane protein containing characteristic proline-rich and glycine-rich regions in its ectodomain. Homology searches resulted in finding homologous sequences (totally about 40% homology) in the human MIC2 gene product (CD99; 32-kDa) of T lymphocytes. These results suggest that the VAP21 antigen in the rabies virion is a cellular CD99-related transmembrane protein.

Cloning and chromosomal mapping of a novel ABC transporter gene (hABC7), a candidate for X-linked sideroblastic anemia with spinocerebellar ataxia

We isolated a novel human ATP-binding cassette (ABC) transporter cDNA, determined its nucleotide sequence, and designated it human ABC7 (hABC7). The nucleotide sequence was highly homologous to the ATM1 gene in yeast, which encodes an ABC transporter (yAtm1p) located in the mitochondrial inner membrane. The deduced human product, a putative half-type transporter, consists of 752 amino acids that are 48.9% identical to those of yAtm1p. A computer-assisted protein structural and localization analysis revealed that the mitochondrial targeting signal of yAtm1p is conserved in the N-terminal region of the primary sequence of the hABC7 protein, and therefore this product is also likely to be located in the mitochondrial inner membrane. The evidence strongly suggests that the hABC7 gene is a counterpart of ATM1 and that its product is probably involved in heme transport. We mapped the hABC7 gene to chromosome Xq13.1-q13.3 by fluorescence in-situ hybridization. As band Xq13 has been implicated in X-linked sideroblastic anemia with spinocerebellar ataxia, hABC7 becomes a candidate gene for this heritable disorder.

Interrelationships of clinical outcome, length of resection, and energy cost of walking after prosthetic knee replacement following resection of a malignant tumor of the distal aspect of the femur

The relationships between the functional score according to the system of the International Society of Limb Salvage, the extent of resection, energy cost of walking, and gait characteristics were studied in thirty-six patients who had had segmental knee replacement after resection of a malignant tumor of the distal aspect of the femur. The mean free-walking velocity was 62.3 meters per minute (79 per cent of normal), which was a result of decreases in both cadence and stride length. The mean net energy cost during walking was 35 per cent greater than that of normal controls and correlated with the percentage of the femur that had been resected. All patients had decreased single-limb support time on the affected side compared with the unaffected side. There was a weak correlation between the asymmetry of the single-limb support time and the percentage of the femur that had been resected. The mean extensor torque of the affected knee was 30 per cent that of the unaffected knee when one head of the quadriceps muscle had been excised, 19 per cent when two heads had been excised, 4 per cent when three heads had been excised, and 1 per cent when four heads had been excised. The patients who had had an extra-articular resection had lower mean extensor and flexor torques at the knee compared with those who had had an intra-articular resection. The asymmetry of the single-limb support time was inversely related to the residual extensor and flexor torques. The overall score according to the system of the International Society of Limb Salvage ranged from 17 to 29 points (mean, 24.6 points; 82 per cent of normal). The net energy cost, percentage of maximum aerobic capacity, and asymmetry of the single-limb support time had significant negative correlations with the overall functional score. Multivariate analysis showed that the overall functional score and the percentage of the femur that had been resected were the two most important factors that predicted the net energy cost. To our knowledge, this is the first objective validation of the functional score according to the system of the International Society of Limb Salvage. As the net energy cost can be predicted from universally available, inexpensive measures, investigators can easily use it as a clinical and research tool to evaluate prosthetic performance and to assess operative outcome.

Prosthetic knee replacement after resection of a malignant tumor of the distal part of the femur. Medium to long-term results

We evaluated the medium to long-term results of treatment with a custom prosthetic knee replacement after wide resection of a primary malignant tumor of the distal part of the femur in forty consecutive patients. The duration of follow-up ranged from five to seventeen years (median, eight years). At the time of the latest follow-up, thirty-five (88 per cent) of the forty patients were free of disease and five (13 per cent) were alive with metastatic disease. No local recurrence was observed. Twenty early complications occurred in eighteen patients (45 per cent). Aseptic loosening of the femoral component, which necessitated a revision in eleven patients at an average of fifty-one months, was the most frequent mode of failure. The rate of prosthetic survival, as estimated with use of the Kaplan-Meier method, was 85, 67, and 48 per cent at three, five, and ten years. Univariate analysis demonstrated that the rate of prosthetic survival was significantly worse for male patients, for those in whom at least 40 per cent of the femur had been resected, for those who had had total resection of the quadriceps muscles or subtotal resection (preservation of only the rectus femoris muscle), and for those in whom a straight femoral stem had been used (p < 0.05 for all comparisons). Multivariate analysis showed that the independent adverse prognostic factors for prosthetic survival were male gender, resection of at least 40 per cent of the femur, and fixation of the femoral stem with cement. The rate of limb salvage was calculated, with use of the Kaplan-Meier method, to be 93 per cent at three years and 90 per cent at five and ten years. At the latest follow-up examination, the functional scores according to the classification system of the Musculoskeletal Tumor Society ranged from 14 to 29 points; the mean was 24 points, which represents function that is 80 per cent that of normal. The mean scores in the categories of walking supports and gait were better for the patients in whom the quadriceps muscles had been preserved than for those who had had total or subtotal resection of those muscles. Although advances in imaging and local therapy narrow the indications for an extra-articular resection of a tumor, the implant that was used in the present study continues to be used in approximately 15 per cent of patients who have a fracture or an intra-articular extension of the tumor that necessitates extensive extra-articular resection.

Studies on the antiviral mechanisms of protein kinase inhibitors K-252a and KT5926 against the replication of vesicular stomatitis virus

We investigated the antiviral mechanisms of K-252a, a broad non-specific protein kinase inhibitor which was isolated from Nocardiopsis sp. and its derivative (KT5926), against vesicular stomatitis virus (VSV) replication in BHK-21 cells. Although K-252a (5 microM) and KT5926 (15 microM) similarly suppressed the viral primary and secondary transcriptions and genomic RNA synthesis in vivo, the inhibitory mechanisms did not seem to be the same; phosphorylation of the viral NS protein was suppressed by K-252a, which might account for the decreased viral RNA synthesis caused by K-252a. On the other hand, KT5926, being known to preferentially inhibit myosin light chain kinase (MLCK), had little effect on NS protein phosphorylation. Cellular casein kinase II, which is believed to be involved in the phosphorylation of the N-terminal side (domain I) of NS protein, was not inhibited at all by KT5926 even at 15 microM under in vitro assay conditions, and was only weakly inhibited by K-252a at 1 to 10 microM. Neither inhibitor seemed to directly affect viral protein synthesis, but affected it indirectly as a secondary effect of reduced viral RNA synthesis. These results suggest that both the KT5926-sensitive and the KT5926-resistant but K-252a-sensitive functions are involved in the essential processes of viral RNA synthesis. The KT5926-sensitive function(s) might not be involved in the NS protein phosphorylation, but may participate in some other way in the process of virus replication. On the other hand, the KT5926-resistant, K-252a-sensitive function(s) are probably involved in NS protein phosphorylation. The possible nature of those functions is discussed.

EWS-FLI1 fusion transcript structure is an independent determinant of prognosis in Ewing's sarcoma

PURPOSE

More than 90% of Ewing's sarcomas (ES) contain a fusion of the EWS and FLI1 genes, due to the t(11;22)(q24;q12) translocation. At the molecular level, the EWS-FLI1 rearrangements show great diversity. Specifically, many different combinations of exons from EWS and FLI1 encode in-frame fusion transcripts and result in differences in the length and composition of the chimeric protein, which functions as an oncogenic aberrant transcription factor. In the most common fusion type (type 1), EWS exon 7 is linked in frame with exon 6 of FLI1. As the fundamental pathogenetic lesion in ES, the molecular heterogeneity of these fusion transcripts may have functional and clinical significance.

PATIENTS AND METHODS

We performed a clinical and pathologic analysis of 112 patients with ES in which EWS-FLI1 fusion transcripts were identified by reverse-transcriptase polymerase chain reaction (RT-PCR). Adequate treatment and follow-up data were available in 99 patients treated with curative intent. Median follow-up in these 99 patients was 26 months (range, 1 to 140 months). Univariate and multivariate survival analyses were performed that included other prognostic factors, such as age, tumor location, size, and stage.

RESULTS

Among the 99 patients suitable for survival analysis, the tumors in 64 patients contained the type 1 fusion and in 35 patients contained less common fusion types. Stage at presentation was localized in 74 patients and metastatic in 25. Metastases (relative risk [RR] = 2.6; P = .008), and type 1 EWS-FLI1 fusion (RR = 0.37; P = .014) were, respectively, independent negative and positive prognostic factors for overall survival by multivariate analysis. Among 74 patients with localized tumors, the type 1 EWS-FLI1 fusion was also a significant positive predictor of overall survival (RR = 0.32; P = .034) by multivariate analysis.

CONCLUSION

EWS-FLI1 fusion type appears to be prognostically relevant in ES, independent of tumor site, stage, and size. Further studies are needed to clarify the biologic basis of this phenomenon.

Prognostic factors for patients with sarcomas of the pelvic bones

BACKGROUND

Treatment of malignant tumors of the pelvis represents one of the most difficult problems in musculoskeletal oncology. However, factors that influence the local and systemic control of the disease remain ill-defined.

METHODS

One hundred and two patients with localized pelvic sarcomas who underwent a surgical excision of the tumors were analyzed. The tumor diagnosis was chondrosarcoma in 49 patients, osteosarcoma in 26 patients, Ewing's sarcoma in 20 patients, and other tumors in 7 patients. The tumor was located in the ilium in 65 patients, the pubis in 21 patients, the ischium in 8 patients, and the sacrum in 8 patients. Eighty-three patients underwent a limb-sparing surgery and 19 patients underwent hemipelvectomy. Prognostic factors for local recurrence, metastasis, and survival were analyzed.

RESULTS

At last follow-up, 47 patients were disease free, 7 were alive with disease, and 48 had died. The 5-year survival rate was 55% (chondrosarcoma: 65%, osteosarcoma: 47%, and Ewing's sarcoma: 52%). Inadequate surgical margin emerged as the only independent adverse prognostic factor for local recurrence. For distant metastasis, surgical stage remained as an independent prognostic factor. Patients who underwent a hemipelvectomy and those who had an inadequate surgical margin had significantly poorer survivals.

CONCLUSIONS

Pelvic sarcomas remain diseases with a poor prognosis. Independent prognostic factors are few; an adequate surgical margin is critical to prevent local recurrence, and the surgical stage is related to the risk of distant metastasis. Surgical margins and hemipelvectomy were predictors of survival, but the patients who underwent hemipelvectomy also tended to have the largest, most advanced tumors. Hemipelvectomy should be considered when there is sacral involvement.