Feasibility of a percutaneous technique for repairing proximal femora with simulated metastatic lesions

Fracture of the proximal femur due to metastatic disease is a significant cause of morbidity and mortality among breast cancer patients. Prophylactic surgical fixation is advised for patients at risk of fracture and typically involves placement of an orthopaedic implant. We propose that some proximal femora with metastases can be repaired by removing the lesion and filling the resulting defect with bone cement (polymethylmethacrylate), a procedure that could be performed percutaneously without the use of hardware. We studied the strengths of 12 matched pairs of cadaveric proximal femora under single-limb stance loading. One femur from each pair remained intact, while a simulated metastatic lesion, measuring approximately 75% of the neck diameter, was burred into the neck of the contralateral femur. The defects were repaired using a procedure similar to the one proposed. Femoral strength was measured via mechanical testing to failure. The strengths of the repaired femora averaged 94.7% of the strength of their respective contralateral intact femur (standard deviation, 8.7%). These findings suggest that the proposed procedure may be useful for some patients with metastases in the femoral neck. If the proximal femur could be safely repaired using the proposed technique in place of conventional surgical fixation, the patient would benefit from a shorter and less invasive surgical procedure, less pain and discomfort, greatly reduced recovery time, and a shorter hospital stay-all at a much lower cost.     

Focal adhesion kinase regulates laminin-induced oligodendroglial process outgrowth

In the central nervous system (CNS), myelination of axons occurs when oligodendrocyte progenitor cells undergo terminal differentiation, and initiate process formation and axonal ensheathment. Although Fyn, a member of the Src-family kinases (SFKs), plays an important role in this differentiation process, the substrates of Fyn in oligodendrocytes are largely unknown. Using mass spectrometric analysis, we identified focal adhesion kinase (FAK) as a tyrosine-phosphorylated protein in the rat-derived CG4 oligodendrocyte cell line. Tyrosine phosphorylation of FAK was enhanced during differentiation of CG4 cells in a Fyn-dependent manner. In addition, phosphorylation of FAK was stimulated by laminin, one of the ligands for integrin. Knockdown of FAK expression in CG4 cells suppressed process outgrowth on laminin. Rac1 and Cdc42 activities, which are required for oligodendrocyte process formation, were down-regulated in FAK-knockdown cells. Expression of wild-type (WT) FAK in FAK-knockdown CG4 cells restored outgrowth of processes, but the Y397F mutant lacking the autophosphorylation site did not. These results suggest that FAK/Fyn-mediated activation of Rac1 and Cdc42 is critical for laminin-induced outgrowth of oligodendrocyte processes.     

Liver fibrosis: possible involvement of EMT

Hepatic fibrosis is a wound-healing process in the liver with acute and chronic injury and is characterized by an excess production and deposition of extracellular matrix components. Hepatic stellate cells as well as portal fibroblasts play a pivotal role in the liver fibrogenesis. Regarding the origin of these mesenchymal cells, two hypotheses emerge. One hypothesis argues in favor of BM-derived progenitor cells and a second hypothesis favors epithelial-mesenchymal transition (EMT) in the local formation of these mesenchymal cells from hepatic epithelium. In this short review, we describe (1) the principle mechanisms of hepatic fibrosis, (2) the cells which play a crucial role in hepatic fibrosis, and (3) the possible involvement of EMT in the process of hepatic fibrosis and carcinogenesis.     

Action profiles of statins and calcineurin inhibitors during human mixed lymphocyte reaction

The cell-to-cell interaction through binding intercellular adhesion molecule (ICAM)-1 and CD40 on monocytes and their ligands such as lymphocyte function-associated antigen (LFA)-1 and CD40 ligand (CD40L) on T-cells plays roles in cytokine production and T-cell proliferation. Interleukin (IL)-18, which is elevated in the plasma during acute rejection after organ transplantation, induces the expression of ICAM-1 and CD40 on monocytes, the production of interferon (IFN)-gamma and IL-12 and the proliferation of T-cells during the human mixed lymphocyte reaction (MLR). In addition to the cholesterol lowering effect, statins improve patient survival and decrease rejection episodes in transplant recipients. In the present study, we investigated the difference of effect of statins and calcineurin inhibitors during MLR. 3-Hydroxy-3-methylglutaryl coenzyme-A (HMG-CoA) reductase inhibitors, fluvastatin and pravastatin and statin-derived LFA-1 inhibitors, LFA703 and LFA878, which did not inhibit HMG-CoA reductase, suppressed the production of IFN-gamma and IL-12 and the lymphocyte proliferation as well as the expression of ICAM-1 and CD40 on monocytes regardless of the presence of IL-18. However, the calcineurin inhibitors, tacrolimus and cyclosporine A (CsA), inhibited the IL-18-enhanced cytokine production and lymphocyte proliferation without any effect on the adhesion molecule expression. Thus, the action mechanism of stain is different from that of calcineurin inhibitors.     

Congenital arhinia: molecular-genetic analysis of five patients

Congenital arhinia, complete absence of the nose, is an extremely rare anomaly with unknown cause. To our knowledge, a total of 36 cases have been reported, but there has been no molecular-genetic study on this anomaly. We encountered a sporadic case of congenital arhinia associated with a de novo chromosomal translocation, t(3;12)(q13.2;p11.2). This led us to analyze the patient by BAC-based FISH for translocation breakpoints and whole-genome array CGH for other possible deletions/duplications in the genome. We found in this patient an approximately 19 Mb deletion spanning from 3q11.2 to 3q13.31 but no disruption of any gene(s) at the other breakpoint, 12p11.2. As the deleted segment at 3q was a strong candidate region containing the putative arhinia gene, we also performed the array CGH in four other arhinia patients with normal karyotypes, as well as mutation analysis of two genes, COL8A1 and CPOX, selected among hundreds of genes located to the deleted region, because they are expressed during early stages of human craniofacial development. However, in the four patients, there were no copy number aberrations in the region examined or no mutations in the two genes. Although our study failed to identify the putative arhinia gene, the data may become a clue to unravel the underlying mechanism of arhinia.     

Seroepidemiology of human bocavirus in Hokkaido prefecture, Japan

A new human virus, provisionally named human bocavirus (HBoV), was discovered by Swedish researchers in 2005. A new immunofluorescence assay using Trichoplusia ni insect cells infected with a recombinant baculovirus expressing the VP1 protein of HBoV was developed, and the levels of immunoglobulin G antibody to the VP1 protein of HBoV in serum samples were measured. The overall seroprevalence rate of antibodies against the VP1 protein of HBoV in a Japanese population aged from 0 months to 41 years was 71.1% (145 of 204). The seropositive rate was lowest in the age group of 6 to 8 months and gradually increased with age. All of the children had been exposed to HBoV by the age of 6 years. A rise in titers of antibody against the VP1 protein of HBoV during the convalescent phase was observed for four patients with lower respiratory tract infections, and HBoV DNA was detected in nasopharyngeal swab and serum samples from all four patients. These results suggest that HBoV is a ubiquitous virus acquired early in life and that HBoV might play a role in the course of lower respiratory tract infections.     

Dok-1 and Dok-2 are negative regulators of T cell receptor signaling

Interaction of the TCR complex with self- or foreign peptides is a central event in the immune responses. Upon TCR stimulation, a protein-tyrosine kinase (PTK), ZAP-70, is recruited to signaling units of the TCR complex, such as TCRzeta, to play an essential role in T cell activation. Here, we find that mice lacking adaptor proteins Dok-1 and Dok-2 show augmented responses to thymus-dependent, but not thymus-independent, antigens, and that their T cells show elevated responses to TCR stimulation, including the activation of ZAP-70 and subsequent proliferation and cytokine production. Furthermore, the forced expression of Dok-1 or Dok-2 in a CD3(+)CD4(+) T cell clone inhibited the activation of ZAP-70 upon TCR stimulation. Interestingly, the Dok-1 and Dok-2 COOH-terminal moieties bearing the src homology 2 target motifs were dispensable for this negative regulation, even though they are crucial for the known adaptor function of Dok-family proteins. Thus, by an as yet unidentified mechanism, Dok-1 and Dok-2 play an essential role in the negative regulation of TCR signaling. Consistently, all mice lacking these proteins exhibited elevated titers of antibodies to double-stranded DNA and developed lupus-like renal disease.     

Time density curve of dynamic contrast-enhanced computed tomography correlates with histological characteristics of pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is characterized by an infiltrative growth pattern with intense desmoplastic stroma comprised of cancer-associated fibroblasts (CAFs). Additionally, the histological characteristics are considered to play a vital role in the poor prognosis of PDAC. However, the density of cancer cells, degree of desmoplasia and vascular proliferation varies in individual cases. We hypothesized that preoperative radiological images would reflect histological characteristics, such as cancer cell density, CAF density and microvessel density. To clarify the association between the histological characteristics and radiological images of PDAC, the cancer cell density, CAF density and microvessel density from surgical specimens were measured with immunostaining, and the time density curve of dynamic contrast-enhanced computed tomography (CECT) was analyzed. Overall, the initial slope between non-enhanced and arterial phases was correlated with microvessel density, and the second slope between arterial and portal phases was correlated with CAF and cancer cell densities. In conclusion, the present study suggested the possibility of estimating cancer cell, CAF and microvessel densities using the TDC of dynamic CECT.     

Dietary diacylglycerol induces the regression of atherosclerosis in rabbits

Recent studies of the relation between serum triacylglycerol concentration and the risk for coronary artery disease suggest that inefficient clearance of postprandial triacylglycerols promotes atherogenesis. We recently demonstrated that dietary diacylglycerol (DAG), rich in the 1,3-species, suppresses the postprandial increase in serum triacylglycerol levels compared with dietary triacylglycerol (TAG). Here, we investigated the effects of dietary DAG on atherosclerosis in rabbits with cholesterol-induced atherosclerosis. New Zealand White rabbits (n = 20) were fed a diet containing 3% lard and 1.3% cholesterol for 50 d to induce atherosclerotic lesions. Thereafter, the rabbits were assigned to 2 groups and fed 90 g/d nonpurified diet and orally administered 5 g DAG or TAG for an additional 34 d. Reference rabbits (n = 5) were fed only the nonpurified diet throughout the 84-d study. The area of atherosclerotic lesions and aortic lipid concentrations were significantly lower in DAG-fed rabbits compared with TAG-fed rabbits. The VLDL receptor and macrophage antigen-1 mRNA expression levels were significantly lower in DAG-fed rabbits than in TAG-fed rabbits. In the liver of DAG-fed rabbits, the triacylglycerol concentration was lower and the carnitine palmitoyltransferase activity higher than in TAG-fed rabbits. Stimulation of hepatic lipid catabolism might be related to the reduced lipid accumulation in the liver and aorta by reducing the release of triacylglycerol into the circulation. Thus, long-term consumption of DAG, which reduces postprandial lipemia, might be useful for the regression of atherosclerosis by stimulating hepatic lipid catabolism and thereby modulating monocyte/macrophage migration and aortic lipid accumulation.