Additive Influence of Extracellular pH, Oxygen Tension, and Pressure on Invasiveness and Survival of Human Osteosarcoma Cells.

Background/purpose: The effects of chemical and physical interactions in the microenvironment of solid tumors have not been fully elucidated. We hypothesized that acidosis, hypoxia, and elevated interstitial fluid pressure (eIFP) have additive effects on tumor cell biology and lead to more aggressive behavior during tumor progression. We investigated this phenomenon using three human osteosarcoma (OS) cell lines and a novel in vitro cell culture apparatus.

Tumour interstitial fluid pressure may regulate angiogenic factors in osteosarcoma.

Purpose: We have previously shown that osteosarcomas have states of increased interstitial fluid pressure (IFP) which correlate with increased proliferation and chemosensitivity. In this study, we hypothesized that constitutively raised IFP in osteosarcomas regulates angiogenesis.

Materials And Methods: Sixteen patients with the clinical diagnosis of osteosarcomas underwent blood fl ow and IFP readings by the wick-in-needle method at the time and location of open biopsy.

Tumor interstitial fluid pressure may regulate angiogenic factors in osteosarcoma.

We have previously shown that osteosarcomas (OS) have states of increased interstitial fluid pressure (IFP), which correlate with increased proliferation and chemosensitivity. In this study, we hypothesized that constitutively raised IFP in OS regulates angiogenesis. Sixteen patients with the clinical diagnosis of OS underwent blood flow and IFP readings by the wick-in-needle method at the time and location of open biopsy.

Bisphosphonate delivery to tubular bone allografts.

Large structural allografts used for reconstruction of bone defects after revision arthroplasty and tumor resection fracture up to 27% of the time from osteolytic resorption around the fixation screw holes and tendon or ligament attachment sites. Treating structural allografts before implantation with bisphosphonates may inhibit local osteoclastic processes and prevent bone resorption and the development of stress risers, thereby reducing the long-term fracture rate. Taking advantage of allografts' open-pore structure, we asked whether passive soaking or positive-pressure pumping was a more efficient technique for delivering bisphosphonates.

Influence of carboplatin infusion on osteosarcoma blood flow.

Purpose: Herein we report that carboplatin infusion influenced tumor blood flow signal independent of the mechanical decompression induced by the artificial lymphatics system technology that was being evaluated as part of a randomized veterinary clinical trial, treating spontaneously occurring canine appendicular osteosarcoma, a tumor very similar to its human counterpart.

Methods: Blood flow within the central region of the tumor was recorded continuously using laser Doppler flowmetry, a real-time measurement technology. Time-averaged flow values were computed from segments taken from the recordings immediately before starting carboplatin infusion, and during infusion.

Use of an artificial lymphatic system during carboplatin infusion to improve canine osteosarcoma blood flow and clinical response.

Background: The artificial lymphatic system (ALS), a mechanical system designed to reduce increased interstitial fluid pressure in solid tumors and enhance the delivery of chemotherapy, was evaluated within a randomized clinical trial treating spontaneously occurring canine appendicular osteosarcoma (OS), a tumor similar to its human OS counterpart.

Methods: An ALS was investigated for its ability to increase OS blood flow and increase uptake of intravenously administered carboplatin.

Results: Blood flow increased by 314% in tumors with active ALS drains versus 126% in control tumors (P < .

Use of an absorbable membrane to position biologically inductive materials in the periprosthetic space of cemented joints.

A device is presented that positions ultrahigh molecular weight polyethylene (UHMWPE) debris against periprosthetic bone surfaces. This can facilitate the study of aseptic loosening associated with cemented joint prostheses by speeding the appearance of this debris within the periprosthetic space. The device, composed of a 100 microm thick bioabsorbable membrane impregnated with 1.

Cell proliferation of cultured human cancer cells are affected by the elevated tumor pressures that exist in vivo.

Elevated interstitial fluid pressure (IFP) is observed in most solid tumors. However, the study of the cellular processes of tumors and the development of chemotherapy are routinely studied using in vitro culture systems at atmospheric pressure. Using a new pressurized cell culture system, we investigated the influence of hydrostatic pressure on population dynamics of three primary osteosarcoma (HOS, U2OS, SaOS2) and two metastatic tumor cell lines (MCF7 breast, H1299 lung) that invade bone.

Elevated physiologic tumor pressure promotes proliferation and chemosensitivity in human osteosarcoma.

Purpose: This study investigates the effect of constitutively raised interstitial fluid pressure on osteosarcoma physiology and chemosensitivity.

Experimental Design: We did pressure and blood flow assessments at the time of open biopsy in patients with the diagnosis of high-grade osteosarcoma and correlated this to survival and chemotherapy-associated tumor necrosis. Osteosarcoma cell lines were then evaluated for proliferative and therapeutic indices in a replicated high-pressure environment.

Biomechanical analysis of anterior poly-methyl-methacrylate reconstruction following total spondylectomy for metastatic disease.

Study Design: Three reconstruction options were evaluated biomechanically following total spondylectomy using human cadaveric spine specimens. OBJECTIVES.: To evaluate and compare the stability of combined anterior and posterior fixation incorporating poly-methyl-methacrylate with alternative accepted reconstruction techniques.

Dog osteogenic sarcoma microvasculature observed with a Spälteholz technique.

A well-distributed, patent microvascular network is essential for adequate, uniform delivery of chemotherapy into solid tumors. This network has not been evaluated in osteogenic sarcoma. Spälteholz tissue clarification was used to observe the microvasculature of canine humeri bearing osteogenic sarcoma.

PMMA to stabilize bone and deliver antineoplastic and antiresorptive agents.

Antineoplastic and antiresorptive drugs added to polymethylmethacrylate cement may prevent local cancer progression and failure of reconstructive devices used to treat patients with pathologic fractures. We tested the mechanical properties of cement containing various amounts of the drugs and found that as much as 2 g of either doxorubicin or pamidronate can be added to Simplex cement and the cement retains 87% of its compressive and tensile strength after 6 months of wet storage. Approximately 1 mg pamidronate elutes from experimental pellets.