Diagnostic strategy for bone and soft-tissue tumors

The diagnostic strategy to be used for a bone tumor depends on the ability of the clinician to make an accurate differential diagnosis on the basis of clinical information and plain radiographs. The clinician must be able to classify the patient as having a non-progressive or a progressive primary benign bone tumor, a primary malignant bone tumor, or a metastatic bone tumor. Only after assignment to one of these four categories can an effective diagnostic strategy ensue. If the clinical and radiographic information favors a diagnosis of malignant or aggressive benign bone tumor, the clinician should refer the patient to an experienced orthopaedic oncologist without performing additional diagnostic tests or a biopsy. If a soft-tissue mass is five centimeters in diameter or larger on physical examination, and especially if it is deep to the fascia, the patient should also be referred to an orthopaedic oncologist, without additional evaluation or biopsy, because of the relatively high probability that the mass is malignant.

Clinical and pathologic findings in infant rhesus macaques infected with SIVsmm by maternal transmission

Three of 12 infant rhesus macaques became infected at 9 to 12 months of age with SIVsmm through maternal-infant transmission. Clinical problems seen in one or more infants included decreased CD4 cells, hypergammaglobulinemia, diarrhea, weight loss, anemia, bacterial infections, and terminal respiratory and CNS problems. Gross and histologic lesions due to both primary SIV infection and opportunistic infections were observed. The SIV-infected infants had clinical, immunologic, and pathologic similarities to those seen in pediatric HIV infection.

Arteriopathy in macaques infected with simian immunodeficiency virus

BACKGROUND

An arteriopathy characterized by intimal and medial thickening and fibrosis was seen in 19 of 85 rhesus monkeys infected with simian immunodeficiency virus (SIV), a lentivirus with morphologic, genetic, and biologic similarities to HIV-1 and HIV-2.

EXPERIMENTAL DESIGN

All cases of simian AIDS in rhesus monkeys at the New England Regional Primate Research Center, resulting from either experimental or naturally acquired SIV infection, were retrospectively examined for evidence of histopathologic changes to the vasculature. Of the 85 SIV-related deaths recorded in the pathology files to date, tissues from 19 animals were chosen for further study because of thickening, disruption, inflammation, or other abnormality to any layer of the vascular wall. The lesion was characterized by special stains, immunoperoxidase procedures, and ultrastructural examination.

RESULTS

Affected monkeys of both sexes varied in age from 4 months to 17 years at the time of inoculation and survived from 41 days to 4 years after infection. Pulmonary arteries were affected in all 19 animals, while vessels in other parenchymal organs were involved less frequently. In addition to sometimes marked intimal thickening with luminal occlusion, the internal elastic laminae were fragmented and interrupted. Seven of 19 animals had pulmonary thromboses with varying degrees of organization and recanalization. Immunohistochemical studies, special stains, and ultrastructural analyses revealed the thickened intimae to be composed predominantly of collagen, extracellular matrix, and smooth muscle cells. Ultrastructurally, endothelial cells from both early (no intimal thickening) and advanced lesions were plump, vacuolated, and often disorganized and detached from the subendothelial space. Increased numbers of macrophages (CD68+) were found in the adventitia and occasionally in the thickened intima and media. Rare, fully differentiated macrophages (CD68+, 25F9+) were demonstrated in lumina of affected vessels, some of which expressed p27 SIV gag protein. However, the lesion was not uniformly associated with localization of either viral protein or RNA at the site using immunohistochemistry or in situ hybridization, respectively. A similar arterial lesion has been described in children with AIDS.

CONCLUSIONS

The morphologic findings in macaques and their similarity to arteriosclerotic changes induced by experimental endothelial damage in other species collectively suggest that arteriopathy in AIDS may represent a manifestation secondary to primary endothelial injury.

The growth inhibitory action of melatonin on human breast cancer cells is linked to the estrogen response system

The pineal hormone, melatonin, was examined for its capacity to modulate the proliferation of a panel of human breast cancer cell lines. Melatonin inhibited, to a varying extent, the proliferation of all three estrogen-responsive cell lines, but had no effect on estrogen-insensitive breast tumor cell lines. Melatonin was also able to specifically block estrogen-induced proliferation in MCF-7 breast cancer cells. However, this action was abolished in the presence of tamoxifen. Therefore, it appears that the antiproliferative effects of melatonin are mediated through the estrogen-response pathway.

Clinical pharmacokinetics of R(+)- and S(-)-mepivacaine after high doses of racemic mepivacaine with epinephrine in the combined psoas compartment/sciatic nerve block

The purpose of this study was to investigate the pharmacokinetics of R(+)- and S(-)-mepivacaine in 10 male patients after injection of a high dose (731 mg) of racemic R,S-mepivacaine for a combined psoas compartment/sciatic nerve block. Arterial blood samples were taken, and the plasma concentrations of the stereoisomers R(+)- and S(-)-mepivacaine were measured by means of high-performance liquid chromatography (HPLC) with a Chiral AGP column. The S(-) isomer reached higher plasma concentrations than the R(+) isomer. The maximal plasma concentration (Cmax) of R(+) was 1.54 +/- 0.34 micrograms/mL, whereas that of the S(-) isomer was 2.34 +/- 0.51 micrograms/mL (P = 0.00050). The time at which Cmax was reached (Tmax) was identical for both isomers. The area under the plasma concentration-time curve from t = 0 to infinity (AUC infinity) of S(-)-mepivacaine was almost double that of R(+)-mepivacaine. The elimination half-life (T1/2) was identical for both isomers (3 h), which means that the calculated total body clearance and the calculated steady-state volume of the distribution of R(+) are, respectively, 1.7 and 1.5 times larger than that of the S(-) isomer. We conclude that the plasma concentrations of the S(-)-mepivacaine isomer were higher than those of the R(+) isomer because of a smaller volume of distribution and a slower total body clearance.

Simian virus 40-induced disease in rhesus monkeys with simian acquired immunodeficiency syndrome

Simian virus 40 (SV40) disease was diagnosed in four rhesus monkeys that died with SIV-induced acquired immunodeficiency syndrome (AIDS). One juvenile monkey seroconverted for SV40 6 months after inoculation with SIV and developed severe bilateral tubulointerstitial nephritis. In contrast, progressive multifocal leukoencephalopathy (PML) occurred in two adult monkeys that were seropositive for SV40 before SIV inoculation, as well as a third adult that was naturally infected with SIV and seropositive for SV40 5 years before death. Large intranuclear inclusions containing abundant polyomavirus particles were limited to either renal tubular epithelial cells or oligodendrocytes. In situ DNA hybridization for SV40 large T antigen further demonstrated that SV40 nucleic acid was localized to either kidney or brain tissue. By immunohistochemical analysis, areas of central nervous system inflammation and demyelination were shown to contain CD68+ macrophages (gitter cells), aggregates of CD8+ T lymphocytes, and numerous gemistocytic astrocytes that labeled for glial fibrillary acidic protein. These observations indicate that rhesus monkeys with SIV-induced AIDS are predisposed to polyomaviral disease, in which SV40 nucleic acid is observed in renal tissue in primary infections and brain tissue after viral reactivation. Furthermore, this organ-specific replication suggests that tissue-tropic strains of SV40 may develop in immunodeficient monkeys.

Evaluation, prognosis, and medical treatment considerations of metastatic bone tumors

Metastatic cancer can cause severe pain and disability. Metastases can occur in any bone, but usually are located in the axial or proximal appendicular skeleton. The most frequently encountered primary tumors that spread to bone are those of the prostate, breast, kidney, lung, and thyroid. When the origin of the primary cancer is known, skeletal metastases are more often from breast or prostate. When the primary site is unknown, the lung and kidney should be suspected as sites of origin. The nonoperative management of skeletal metastases from multiple myeloma and from carcinomas of the prostate, breast, kidney, lung, and thyroid are discussed.

Pathologic features of SIV-induced disease and the association of macrophage infection with disease evolution

Since the original isolation of simian immunodeficiency virus (SIV) from a macaque with an AIDS-like disease, numerous studies have demonstrated the close biologic and genetic relationship of the SIVs to the HIVs. Probably most important, the clinical spectrum of disease associated with SIVmac/SIVsmm infection in rhesus monkeys is strikingly similar to AIDS in HIV-1-infected human beings. Herein are summarized the pathologic features of SIVmac-induced disease in a cohort of rhesus monkeys, with special reference to the role of infected macrophages in the development of AIDS-related manifestations.

Signalling by the sevenless protein tyrosine kinase is mimicked by Ras1 activation

Cell-fate specification of R7 photoreceptors in the developing Drosophila eye depends on an inductive signal from neighbouring R8 cells. Mutations in three genes, sevenless (sev), bride-of-sevenless (boss) and seven-in-absentia (sina) cause the R7 precursor to become a non-neural cone cell. The sev gene encodes a receptor protein tyrosine kinase (Sev) localized on the R7 surface, activated by a boss-encoded ligand presented by R8. The sina gene encodes a nuclear factor required in R7. Reduction in the dosage of the Ras1 gene impairs Sev-mediated signalling, suggesting that activation of Ras1 may be an important consequence of Sev activation. We report here that Ras1 activation may account for all of the signalling action of Sev; an activated Ras1Va112 protein rescues the normal R7 precursor from transformation into a cone cell in sev and boss null mutants and induces the formation of supernumerary R7 cells. Similar activation of the Drosophila Ras2 protein does not produce these effects, demonstrating Ras protein specificity.

Medical management compared with operative treatment for osteoid-osteoma

Twenty-four patients were evaluated and diagnosed, between August 1975 and July 1989, as having probable osteoid-osteoma. Fifteen patients had operative treatment (twelve immediate and three delayed); all fifteen had complete relief of pain. The remaining nine patients were treated with non-steroidal anti-inflammatory medications; all nine had complete relief of pain, and six had resolution of the symptoms without using non-steroidal anti-inflammatory drugs, after an average of thirty-three months (range, thirty to forty months) of treatment. Thus, long-term administration of non-steroidal anti-inflammatory drugs can often be as effective as excision for the treatment of osteoid-osteoma, without the morbidity that is associated with the operation, especially in patients in whom operative treatment would be complex or might lead to disability.

Ras1 and a putative guanine nucleotide exchange factor perform crucial steps in signaling by the sevenless protein tyrosine kinase

We have conducted a genetic screen for mutations that decrease the effectiveness of signaling by a protein tyrosine kinase, the product of the Drosophila melanogaster sevenless gene. These mutations define seven genes whose wild-type products may be required for signaling by sevenless. Four of the seven genes also appear to be essential for signaling by a second protein tyrosine kinase, the product of the Ellipse gene. The putative products of two of these seven genes have been identified. One encodes a ras protein. The other locus encodes a protein that is homologous to the S. cerevisiae CDC25 protein, an activator of guanine nucleotide exchange by ras proteins. These results suggest that the stimulation of ras protein activity is a key element in the signaling by sevenless and Ellipse and that this stimulation may be achieved by activating the exchange of GTP for bound GDP by the ras protein.

Limb salvage for osteosarcoma in the 1980s

The incidence of local recurrences following limb salvage performed by experienced surgeons with wide surgical margins and with the use of neoadjuvant chemotherapy is sufficiently low (5%-10%) so as not to have a biologically statistically significant impact on the long-term survival rate. Following limb salvage, the incidence of morbidity increases with a few patients occasionally requiring prolonged or repeated hospitalizations and further surgical procedures, even amputation. The durability of the reconstructions is variable, and many of the mobile knee reconstructions may need to be revised if the patients become long-term survivors. The function of salvaged limbs is better than that after the alternative amputation, but none of the reconstructions will give normal function. Finally, no matter which type of surgery on the lower extremity is selected, patients will have a good early psychosocial adjustment if no premorbid psychosocial disorder is present.

The effects of resection of the proximal part of the fibula on stability of the knee and on gait

We studied six patients to determine the effects of unilateral marginal resection of the proximal part of the fibula on stability of the knee and on gait. At the time of the operation, the fibular collateral ligament and the tendon of the biceps femoris were reattached, but no attempt was made to stabilize the fibula otherwise. The patients were tested an average of sixty-one months after operation. Stability of the knee was measured with an instrumented system. Gait was evaluated with an optical electronic three-dimensional digitizing system and a multicomponent force-platform. The gait of six healthy control subjects of similar age was also studied, and the reproducibility of measurements of stability of the knee was investigated in four healthy adults. There were significant differences between the side on which an operation had been done and the contralateral side with regard to the extent of anterior translation and of total anterior-posterior translation of the tibia at both 20 and 90 degrees of flexion of the knee, and in total varus and valgus rotation of the knee (the number of degrees from a position of maximum varus to one of maximum valgus angulation) at 20 degrees of flexion. The measurements of gait and of motion of the knee were found to be normal when compared with those in the control subjects. In the ground-reaction measurements, there were some significant differences from normal in the medial-lateral plane, but they were clinically unimportant. Resection of the proximal part of the fibula can lead to instability of the knee.

Limb-salvage surgery in the treatment of osteosarcoma in skeletally immature individuals

Sacrifice of major growth plates during resection and fixed-length reconstruction of a limb in a skeletally immature child with osteosarcoma may result in a significant limb-length inequality as growth progresses. A limb-length discrepancy in the humerus may cause minor cosmetic problems but does not generally result in a significant functional deficit. In the lower extremity, tumors about the knee, including the distal femur and proximal tibia, usually present the dilemma of whether limb salvage by arthrodesis, osteoarticular allograft, or endoprosthetic replacement would result in a significant limb-length inequality and whether amputation of the extremity is a preferable procedure. The techniques of rotationplasty and an expandable endoprosthesis have been successfully used for treating skeletally immature patients with osteosarcoma of the distal femur. With regard to survival and function, the results obtained with these innovative methods are favorable compared with those of a high above-knee amputation.

Mobile knee reconstructions after resection of malignant tumors of the distal femur

Limb-salvage surgery involving mobile knee reconstructions for malignant tumors about the distal femur is a desirable and achievable goal. With limb salvage, the survival rate does not decrease significantly, and the resulting function is superior to when an amputation plus a prosthesis are used. Immediate and delayed morbidity is greater after limb-salvage surgery than after amputation. However, with thorough preoperative planning, use of neoadjuvant chemotherapy as indicated, and an experienced team of surgeons, limb-salvage surgery can provide a mobile knee with excellent function in the vast majority of cases for patients with malignant tumors of the distal femur.

Function after amputation, arthrodesis, or arthroplasty for tumors about the knee

We studied the function of twenty-two patients who had had a malignant skeletal tumor adjacent to the knee. An above-the-knee amputation was done in seven; a resection arthrodesis, in nine; and a replacement arthroplasty, in six. The patients all walked at a similar speed (sixty-one to sixty-six meters per minute), which is slower than normal (eighty meters per minute). They all walked with comparable efficiency at three velocities: the mean consumption of oxygen was 0.210 milliliter per kilogram of body weight per meter at free velocity, 0.215 milliliter per kilogram of body weight per meter when they walked 25 per cent faster, and 0.211 to 0.240 milliliter per kilogram of body weight per meter when they walked 50 per cent faster. The three groups of patients and a normal control group consumed oxygen at similar rates. The patients who had had an amputation were very active, and they were the least worried about damaging the affected limb, but they had difficulty walking on steep, rough, or slippery surfaces. The patients who had had an arthrodesis had a more stable limb and performed the most demanding physical work and recreational activities, but they had difficulty sitting. The patients who had had an arthroplasty led sedentary lives and were the most protective of the limb, but they were the least self-conscious about the limb.

Radiobiological characterization of head and neck and sarcoma cells derived from patients prior to radiotherapy

The radiobiological parameters of 33 tumor cell lines were studied in biopsy samples obtained from patients prior to radiotherapy. Epithelial tumor cells derived from head and neck cancer patients were more radioresistant than tumor cell lines derived from patients with sarcoma regardless of method of analysis. The presence of radioresistant tumor cell lines was associated with local failure in some patients. However, the presence of radiosensitive tumor cells did not necessarily predict local control. Our data suggest radiocurability is complex and inherent radiobiological parameters of tumor cells may be only one factor in radiotherapy outcome.

Tubular sodium handling in cirrhotic patients with ascites as analysed by the renal lithium clearance method

The proximal and distal sodium reabsorption were calculated from lithium clearance in 21 healthy controls and 24 cirrhotic patients with ascites after 4 days under a sodium-restricted diet. The values of fractional lithium clearance were lower in patients than in controls (7.37 +/- 0.87 vs. 18.13 +/- 1.76%, P less than 0.001). Fractional proximal sodium reabsorption was increased in patients compared with controls (92.8 +/- 1.1 vs. 81.8 +/- 1.7%, P less than 0.001). No differences were found in fractional distal sodium reabsorption between controls and patients (96.9 +/- 0.8 vs. 98.6 +/- 0.1%). When patients were separated into two subgroups according to their sodium balance, it was found that fractional distal sodium reabsorption was increased in patients whose balance remained positive, compared with patients on a negative sodium balance (98.99 +/- 0.26 vs. 94.11 +/- 1.50%, P less than 0.05). In addition, the natriuretic response to a specific dose of spironolactone was higher in patients on positive sodium balance compared with patients on negative sodium balance (per cent increase in natriuresis after spironolactone 300 mg day-1: 355.24 +/- 73.98 vs. 84.21 +/- 15.8%, P less than 0.01). We conclude that proximal sodium reabsorption is increased in cirrhotics with ascites. In addition, distal sodium reabsorption is enhanced only in those patients which exhibit avid sodium retention.

Structure and activity of the sevenless protein: a protein tyrosine kinase receptor required for photoreceptor development in Drosophila

The sevenless gene encodes a putative protein tyrosine kinase receptor that is required for the proper differentiation of the R7 photoreceptor cells of the Drosophila eye. We have expressed the sevenless protein in Drosophila tissue culture cells and studied its synthesis, processing, and activity. Our results show that the sevenless protein possesses protein tyrosine kinase activity. The protein is first synthesized as a 280-kDa glycoprotein precursor that is subsequently cleaved into 220-kDa amino-terminal and 58-kDa carboxyl-terminal subunits that remain associated by noncovalent interactions. The 220-kDa subunit is glycosylated and contains most of the extracellular portion of the protein, and the 58-kDa subunit is composed of a small portion of the extracellular sequences and the intracellular protein tyrosine kinase domain. This complex is subsequently cleaved into either 49- or 48-kDa carboxyl-terminal fragments with concomitant degradation of the rest of the protein.

Staging systems for musculoskeletal neoplasms

In the treatment of musculoskeletal neoplasms, preservation of limb function and prolongation of survival have improved over the past decade. With the current emphasis on limb salvage procedures for local control of tumors, and with the addition of adjunctive therapy, the ability to classify and stage these unusual tumors is important in determining prognosis and treatment. In such classifications, a number of prognostic factors are identified and used to define stages. Three recognized staging systems exist for sarcomas of soft tissues and two for sarcomas of bone; there is one system for benign tumors of bone. The prognostic variables used in assigning stages are common to all of these systems, but the relative significance assigned to these variables differs. Documented improvement in survival and preservation of function suggests that current staging systems are significantly affecting outcome in the management of musculoskeletal tumors.

Regulation of the complex pattern of sevenless expression in the developing Drosophila eye

The sevenless gene encodes a cell surface receptor that has protein-tyrosine kinase activity and is expressed in a highly specific and complex pattern in the developing Drosophila eye. We have coupled the sevenless promoter to the reporter gene lacZ and have examined the pattern of beta-galactosidase expression in the developing eyes of transgenic larvae. Our results indicate that the dynamic pattern of sevenless protein expression is regulated transcriptionally. Promoter sequences located 5' of the coding region are insufficient for the wild-type level of gene expression but appear to be able to confer the correct pattern of expression. In contrast, enhancer sequences within the body of the gene can confer both the correct pattern and a normal level of expression on either the sevenless promoter or heterologous promoters. Thus the complex pattern of sevenless expression is redundantly encoded within proximal promoter sequences and enhancer elements internal to the gene but relies on these enhancer sequences for correct quantitative expression.

Studies of the retinoblastoma gene in human sarcomas

The retinoblastoma susceptibility gene, (RB), is a tumor suppressor gene which, when deleted is associated with the development of retinoblastoma. The observation that children with heritable retinoblastoma frequently develop second malignancies, principally sarcomas, led to the detection of similar RB gene deletions in some osteosarcomas. We studied 44 unselected sarcomas from patients with no antecedent retinoblastoma to determine the prevalence and nature of RB gene alterations. DNA and RNA were extracted from fresh tumors and analysed by Southern and Northern blotting. Three of nine osteosarcomas and 4 of 29 soft-tissue sarcomas had deletions of the RB gene. Four of these were full-length, and three were partial deletions of the gene. RNA from 5 of the 7 deleted tumors was studied, and 4 cases completely lacked the RB transcript. Transcripts were found in 19 of 20 tumors with an apparently intact RB gene, and in all the normal tissues studied. An additional tumor lacked the RB transcript, but the gene appeared intact at the DNA level. In total, 8 of 38 sarcomas were found to have alterations of the RB gene. These data indicate that the RB gene is inactivated in a significant number of sarcomas unrelated to retinoblastoma, and that the potential role for the gene in the pathogenesis of human malignancy may not be limited to retinoblastoma.