High-magnitude mechanical strain inhibits the differentiation of bone-forming rat calvarial progenitor cells

Purpose: Orthodontic tooth movement occurs during the bone remodeling induced by therapeutic mechanical strain. It is important to investigate the relation between the strength of mechanical stress and bone formation activity. The aim of this study was to determine the effect of high-magnitude mechanical strain on bone formation in detail.

Materials and methods: Osteoblast-like cells isolated from fetal rat calvariae were loaded with 18% cyclic tension force (TF) for 48?h. To phenotypically investigate the effect of TF, we measured the number and the size of bone nodules stained by von Kossa technique on day 21 after cell seeding and determined the calcium content of bone nodules on day 14. Furthermore, we examined the gene expression of BMP-2, Runx2 and Msx2, which are important factors for bone nodule formation, on days 1, 4 and 7 after TF loading.

Results: The maximum bone nodule size in the control group was 1620 and 719?μm in the TF group. Furthermore, the mean number of bone nodules sized over 360?μm in the TF group was significantly decreased compared to the control group. The calcium content was also significantly decreased to 42% by TF loading. The mRNA expression of BMP-2, Runx2 and Msx2 was decreased 1 and 4 days after TF loading.

Conclusion: The differentiation of bone forming progenitor cells into bone nodule forming cells was inhibited by TF due to the decreased expression of bone formation related factors such as BMP-2, Runx2 and Msx2.     

Pulmonary metastases from epithelial tumours: late results of surgical treatment.

OBJECTIVE: Development of distant metastases is one of the primary characteristics of malignant tumours. During the last decades, lung metastasectomy has been progressively accepted as a therapeutic option in oncology patients. The present paper aims to evaluate the long-term results and factors influencing prognosis in patients submitted to lung resection for metastases from extrapulmonary epithelial tumours. METHODS: We retrospectively analysed data of 202 patients undergoing 207 procedures of lung metastasectomy between January 1980 and December 2003. Factors that may influence long-term prognosis such as completeness of resection, histology of the tumour, disease-free interval, number of resected lesions, involvement of hilar or mediastinal lymph nodes, systemic treatments were investigated. RESULTS: Complete resection was carried out in 169 patients (83.7%). The more frequent lung resection was sublobar in 67.6% of cases, but rarely in selected patients bilobectomy or pneumonectomy has been carried out too. Perioperative morbidity and mortality were 7.7% and 0.9%. Mean disease-free interval was 49+/-48 months. Mean follow-up was 33+/-31 months, 5-year and 10-year survival rates for completely resected patients were 43% and 17%, respectively. By univariate and multivariate analyses, completeness of resection, disease-free interval of 36 months or more, and single resected metastasis were found to be significant prognostic factors. CONCLUSIONS: Resection of epithelial lung metastases allows an acceptable prognostic result in appropriately selected patients with very low perioperative morbidity and mortality. Factors such as high disease-free interval, single metastasis and completeness of resection are demonstrated and confirmed to be significantly associated with long-term survival.     

Hepatitis C virus outside the liver

Observational and some experimental data suggest that hepatitis C virus can manifest in a variety of disease processes outside the liver. The links between hepatitis C virus and membranoproliferative glomerulonephropathy, porphyria cutanea tarda, lichen planus, cryoglobulinemia, diabetes mellitus, B-cell non-Hodgkin’s lymphoma, and thyroiditis are critically reviewed. Based on the available evidence, recommendations for the clinical approach to patients with extrahepatic diseases are discussed.     

Chromosome 2q terminal deletion: report of 6 new patients and review of phenotype-breakpoint correlations in 66 individuals

We report a new patient with terminal deletion of chromosome 2 with breakpoint at 2q36 and five additional new patients with 2q terminal deletion with breakpoint at 2q37. Hemidiaphragmatic hernia is a novel finding in one patient with a breakpoint at 2q37.1. In comparing these patients to 60 previously reported individuals with 2q terminal deletions, certain physical abnormalities are loosely associated with positions of breakpoint. For example, facial features (e.g., prominent forehead, depressed nasal bridge, and dysmorphic ears and nose), short stature, and short hands and feet were frequent in patients with breakpoints at or proximal to 2q37.3. Reports of horseshoe kidney and Wilms tumor were limited to patients with a breakpoint at 2q37.1, and structural brain anomalies and tracheal anomalies were reported only in patients with breakpoints at or proximal to 2q37.1. Cleft palate was reported only in patients with the most proximal breakpoints (2q36 or 2q35). Neurological effects including developmental delay, mental retardation, autistic-like behavior, and hypotonia were typical in this patient population but did not stratify in severity according to breakpoint. Terminal deletion of the long arm of chromosome 2 should be considered in the infant with marked hypotonia, poor feeding, gastroesophageal reflux, and growth delay, and the older child with developmental delay, autistic behavior, and the characteristic facial and integumentary features described herein. Assignment of clinical features to specific breakpoints and refinement of predictive value may be useful in counseling.     

Micropatterned surfaces modified with select peptides promote exclusive interactions with osteoblasts

Microcontact printing techniques were used to pattern circles (diameters 10. 50, 100, and 200 microm) of N1[3-(trimethoxysilyl)-propyl]diethylenetriamine (DETA) surrounded by octadecyltrichlorosilane (OTS) borders on borosilicate glass, a model substrate. The DETA regions were further modified by immobilization of either the cell-adhesive peptides Arginine-Glycine-Aspartic Acid-Serine (RGDS) and Lysine-Arginine-Serine-Arginine (KRSR) or the non-adhesive peptides Arginine-Aspartic Acid-Glycine-Serine (RDGS) and Lysine-Serine-Serine-Arginine (KSSR). After four hours under standard cell culture conditions but in the absence of serum, adhesion of either osteoblasts or fibroblasts on surfaces patterned with the non-adhesive peptides RDGS and KSSR was random and low. In contrast, both osteoblasts and fibroblasts adhered and formed clusters onto circles modified with the adhesive peptide RGDS, whereas only osteoblasts adhered and formed clusters onto the circles modified with KRSR, a peptide that selectively promotes adhesion of osteoblasts. These results provide evidence that patterning of select peptides can direct adhesion of specific cell lines exclusively to predetermined regions on material surfaces.     

Association of tuberculin-boosted antibody responses with pathology and cell-mediated immunity in cattle vaccinated with Mycobacterium bovis BCG and infected with M. bovis

Vaccine development and our understanding of the pathology of bovine tuberculosis in cattle would be greatly facilitated by definition of the immunological correlates of protection and/or pathology. In this study we analyzed humoral immune responses in Mycobacterium bovis BCG-vaccinated and control cattle (in particular, the relationship between the intradermal comparative tuberculin skin test and serum immunoglobulin G [IgG] responses) against a range of mycobacterial antigens (MPB59, MPB64, MPB70, MPB83, ESAT-6, CFP-10, Acr1, and PstS-1) by multiantigen print immunoassay and conventional enzyme-linked immunosorbent assay. Following M. bovis infection, the comparative tuberculin skin test strongly boosted IgG, IgG1, and IgG2 antibody responses, particularly against MPB83 and MPB70, in unvaccinated cattle but failed to boost these responses, or did so only weakly, in BCG-vaccinated calves. In addition, the skin test-induced increases in MPB83-specific IgG responses correlated positively with bacterial loads and ESAT-6-induced in vitro gamma interferon responses. In conclusion, both the negative correlation of skin test-enhanced MPB83-specific antibody responses with BCG-induced protection and their positive correlation with bacterial loads can serve as useful markers for vaccine efficacy after challenge.     

Formation of focal contacts by osteoblasts cultured on orthopedic biomaterials.

The nature of the contact sites formed during the adhesion of osteoblasts to orthopedic implant materials was investigated by fluorescence microscopy. More specifically, the cytoskeletal organization of and the focal contact formation by neonatal rat calvarial osteoblasts attaching to and spreading on 316L stainless steel, Ti-6Al-4V, Co-Cr-Mo, Synamel (hydroxyapatite), alumina, and borosilicate glass were examined. Focal contacts are regions where the plasma membrane approaches the substrate to within 10-15 nm and where bundles of cytoskeletal microfilaments terminate. Fluorescent-labeling of F-actin-containing microfilaments demonstrated a typical sequence of events as rounded, suspended osteoblasts spread onto the substrates. Immunofluorescent-labeling of the protein vinculin, which is found at the cytoplasmic face of focal contacts, initially showed the formation of streak-like focal patches. On the biomaterials, the vinculin staining subsequently extended up and along, but ventral to, the microfilament bundles. The fibrillar patterns observed at later times may evidence the formation of extracellular matrix contacts.