Metastatic prostate carcinoma to the orbit as the first presentation of disease.

Prostate carcinoma is a common tumor of the older adult male. It is associated with bony metastases, particularly to the axial skeleton. We present two case histories; in both cases, the patients had no prior history of prostate carcinoma. Both cases were diagnosed with CT imaging, elevated PSA, and biopsy. Additionally, they were treated with surgical resection and hormone modulation therapy. While bony metastases are frequently associated with advanced disease, they can also be a cause of presenting symptoms. The CT imaging in these two cases showed the classic hyperostotic findings of prostate cancer. Prostate cancer may cause osteoblastic lesions in contrast to other metastatic bone lesions, which cause destructive osteolytic lesions. During excisional surgery, the tumor was inspected and many stalactite-like lesions were present on the gross sample. We present these and compare them to the CT imaging.

Assessment of a bovine co-culture, scaffold-free method for growing meniscus-shaped constructs.

Using a self-assembly (SA), scaffoldless method, five high-density co-cultures with varied ratios of meniscal fibrochondrocytes (MFCs) and articular chondrocytes (ACs) were seeded into novel meniscus-specific, ring-shaped agarose wells. The following ratios of MFCs to ACs were used: 0% MFC, 25% MFC, 50% MFC, 75% MFC, and 100% MFC. Over 4 weeks, all ratios of cells self-assembled into three-dimensional constructs with varying mechanobiological and morphological properties. All groups stained for collagen II (Col II), and all groups except the 0% MFC group stained for collagen I (Col I). It was found that the tensile modulus was proportional to the percentage of MFCs employed. The 100% MFC group yielded the greatest mechanical stiffness with 432.2 +/- 47 kPa tensile modulus and an ultimate tensile strength of 23.7 +/- 2.4 kPa. On gross inspection, the 50% MFC constructs were the most similar to our idealized meniscus shape, our primary criterion. A second experiment was performed to examine the anisotropy of constructs as well as to directly compare the scaffoldless, SA method with a poly-glycolic acid (PGA) scaffold-based construct. When compared to PGA constructs, the SA groups were 2-4 times stiffer and stronger in tension. Further, at 8 weeks, SA groups exhibited circumferential fiber bundles similar to native tissue. When pulled in the circumferential direction, the SA group had significantly higher tensile modulus (226 +/- 76 kPa) than when pulled in the radial direction (67 +/- 32 kPa). The PGA constructs had neither a directional collagen fiber orientation nor differences in mechanical properties in the radial or circumferential direction. It is suggested that the geometric constraint imposed by the ring-shaped, nonadhesive mold guides collagen fibril directionality and, thus, alters mechanical properties. Co-culturing ACs and MFCs in this manner appears to be a promising new method for tissue engineering fibrocartilaginous tissues exhibiting a spectrum of mechanical and biomechanical properties.

A direct compression stimulator for articular cartilage and meniscal explants.

This paper describes the development and use of a direct compression stimulator for culturing explants from the meniscus of the knee and articular cartilage. Following design and fabrication of the instrument along with its data acquisition system, the function of the machine was verified by both mechanical means and tissue effect. The loading chamber can hold up to 45 5 mm diameter samples. While designed to stimulate samples up to 4 mm thick, axial displacements as little as 0.127 microm are within the theoretical capacity of the stimulator. In gene expression studies, collagen II and aggrecan expression were examined in explants from articular cartilage as well as medial and lateral menisci subjected to dynamic stimulation and static compression. These results were then compared to free swelling samples. It was found that static compression to cut thickness down-regulated aggrecan and collagen II expression in articular cartilage explants compared to free swelling controls by 94% and 90%, respectively. The application of a dynamic, intermittent, 2% oscillation around the cut thickness returned expression levels to those of free swelling controls at 4 h but not at 76 h. In medial meniscus samples, dynamic compression up-regulated aggrecan expression by 108%, but not collagen II expression, at 4 and 76 h compared to static controls. No difference in gene expression was observed for lateral meniscal explants. Thus, effects of direct compression seen in articular cartilage may not necessarily translate to the knee meniscus. The design of this stimulator will allow a variety of tissues and loading regimens to be examined. It is hoped that regimens can be found that not only return samples to the production levels of free swelling controls, but also surpass them in terms of gene expression, protein synthesis, and functional properties.

Comparison of scaffolds and culture conditions for tissue engineering of the knee meniscus.

The menisci of the knee are semilunar fibrocartilaginous structures critical in load bearing, shock absorption, stability, and lubrication. In this study, two commonly used biomaterials, a hydrogel (agarose) and a nonwoven mesh polymer [poly(glycolic acid); PGA], were compared for suitability as scaffold materials for tissue engineering the knee meniscus. In addition, a rotating wall bioreactor culture of both scaffold materials was compared with static cultures. Constructs were cultured for up to 7 weeks in static and rotating wall bioreactor culture. Cell numbers were 22 times higher in PGA than agarose after 7 weeks in culture. Static PGA scaffolds had more than twice the amount of sulfated glycosaminoglycans and three times the amount of collagen compared to static agarose constructs at week 7. The rotating wall bioreactor was not found with increase matrix production or cell proliferation significantly over static cultures.

Mechanical stimulation toward tissue engineering of the knee meniscus.

Current clinical practices do not adequately regenerate the meniscus of the knee secondary to a tear. Complete or partial meniscus removal leads to degenerative changes within the joint. Tissue engineering of the meniscus promises a potent solution. Before embarking on tissue engineering of the meniscus, it is crucial to have a thorough comprehension of the biomechanical role that this tissue fulfills and how the structure of meniscus is uniquely suited to that purpose. To better understand this, we have examined the meniscus, as well as associated tissues, within the body. For the first time, the knee meniscus is rigorously compared to ligament, tendon, and cartilage, and inferences are drawn on how mechanical stimulation may be used to channel growth in the meniscus. We have examined in detail the loading conditions that these tissues experience in vivo and how each is uniquely adapted to its loading environment. These tissues are capable of achieving some degree of remodeling because of mechanical stimuli. By understanding the mechanisms that can stimulate and promote regeneration in related tissues, we hope to harness that knowledge to achieve the goal of meniscal regeneration.