Minimally invasive longitudinal intravital imaging of cellular dynamics in intact long bone

Intravital two-photon microscopy enables deep-tissue imaging at high temporospatial resolution in live animals. However, the endosteal bone compartment and underlying bone marrow pose unique challenges to optical imaging as light is absorbed, scattered and dispersed by thick mineralized bone matrix and the adipose-rich bone marrow. Early bone intravital imaging methods exploited gaps in the cranial sutures to bypass the need to penetrate through cortical bone. More recently, investigators have developed invasive methods to thin the cortical bone or implant imaging windows to image cellular dynamics in weight-bearing long bones. Here, we provide a step-by-step procedure for the preparation of animals for minimally invasive, nondestructive, longitudinal intravital imaging of the murine tibia. This method involves the use of mixed bone marrow radiation chimeras to unambiguously double-label osteoclasts and osteomorphs. The tibia is exposed by a simple skin incision and an imaging chamber constructed using thermoconductive T-putty. Imaging sessions up to 12 h long can be repeated over multiple timepoints to provide a longitudinal time window into the endosteal and marrow niches. The approach can be used to investigate cellular dynamics in bone remodeling, cancer cell life cycle and hematopoiesis, as well as long-lived humoral and cellular immunity. The procedure requires an hour to complete and is suitable for users with minimal prior expertise in small animal surgery.

Primary clavicle tumors and tumorous lesions: a review of 206 cases in East Asia

PURPOSE

The aim of this study is to systematically review the published literature from East Asia on the clinical, pathological, and epidemiological characteristics of primary clavicle tumor and tumorous lesions.

METHODS

A computerized search based on keywords "clavicle," "tumor," and "tumorous lesion" (both in Chinese and in English) was performed on literature published from 1980 to 2011 in East Asian countries, including China, Japan, South Korea, North Korea, and Mongolia. An analysis was carried out with unified inclusion and exclusion criteria.

RESULTS

Two hundred and six cases were identified. The age of onset ranged from 1.5 to 70, with an average age of 29.4, and a male/female ratio of 1.53:1. Lesion locations included 28.9% in medial third, 18.8% in the middle third, and 33.6% in the lateral third of the clavicle. Another 7.4% involved both the medial and middle thirds, 7.4% involved both the middle and lateral thirds, and 4.0% involved the entire length of the clavicle. Major pathological types included 18.5% eosinophilic granuloma, 10.2% plasmocytoma, 7.8% Ewing sarcoma, 8.7% osteosarcoma, 8.7% osteochondroma, and 5.3% chondrosarcoma. The age of onset was found to be strongly correlated with the benign/ malignant ratio. Clavicle malignancy was rarely found in patients younger than 10 years, while the incidence of malignancy greatly increased among patients over 40 years old. Total or subtotal claviculectomy was the most common treatment in cases for which treatment information was available. Of these, 40.8% of patients received reconstruction with allograft or autograft.

CONCLUSIONS

Clavicle tumors and tumorous lesions in East Asia had an inclined occurrence in respect to age and gender. The most common tumors were eosinophilic granuloma and tumors derived from the bone marrow hematopoietic system. Age of onset was found to be a risk factor for malignancy. These characteristics may be related to the special tissue structures and mode of development in the clavicle as well as to the genetic traits of the typical Mongoloids in East Asia.