Bone Resorption

The purpose of this investigation was to evaluate the extent to which obesity and/or hypertension may modify the response of rats' periodontium to chronic gingival irritation. Forty-four normal, spontaneously hypertensive, obese, and obese-hypertensive rats were used. Histopathologic evaluation of the periodontal structure showed both hyperplasia and hypertrophy of the walls of blood vessels supplying the periodontium in the hypertensive and obese-hypertensive animals. The results also indicated that obesity significantly contributed to e severity of periodontal disease. Hypertension alone was not a significant factor. The obese-hypertensive rats showed the most severe periodontal response to local irritation.

The effects of Spinal Cord Injury (SCI) on bone in paralyzed areas are well documented but there are few data for the importance of the level of injury in the decrease of mechanical strength in paralyzed legs. The aim of the present study was to describe bone loss of the separate compartments of trabecular and cortical bone in spinal cord injured men and to compare possible changes in mechanical properties of tibia with the neurological level of injury. Fifty men were included in this study: 39 had complete SCI in chronic stage. As chronic stage, we considered paraplegia >1.5 years (yrs). Men were separated as follows: Group A (18 men, high paraplegia: Thoracic (T)4-T7 level, mean age: 33 yrs, duration of paralysis: 5.9 yrs) and group B (21 men, low paraplegia: T8-T12 level, mean age: 39 yrs, duration of paralysis: 5.6 yrs) in comparison with 11 healthy men as a control group (C) of similar age, height, and weight. None of the subjects was given bone acting drugs. The neurologica...

Osteoclasts are multinucleated cells of hematopoietic origin which are unique in their ability to resorb bone. Osteoclasts are generated from myeloid progenitors through a progression that involves the fusion of mononuclear precursor cells. The identification of RANK-RANKL signaling as the main signal regulating osteoclast differentiation was a major breakthrough in the bone biology field. In addition remarkable discoveries have been made to broaden the knowledge of the molecular mechanisms of osteoclast formation and differentiation. Despite the vital requirement of osteoclasts in bone modeling and remodeling, bone-related conditions like osteoporosis, Paget's disease and rheumatoid arthritis where accelerated bone resorption takes place pose a major socioeconomic burden to the society. Hence, a better understanding of the pathways leading to osteoclast differentiation is vital in successfully managing such diseases. This is an attempt to give a birds-eye-view of the players in...

Feline osteoclastic resorptive lesions (FORL) of the teeth are common in cats, and lead to pain, destruction of the periodontal ligament, and tooth loss. The expression of interleukin (IL)-1β and IL-6 mRNA was higher in teeth with FORL than in normal teeth (P<0·01 and P<0·001, respectively), but no such differences were found between pathological and normal gingival tissue samples. There were no differences between teeth affected with FORL and normal teeth in respect of the expression of receptor activator of NFκB ligand (RANKL) mRNA or osteoprotegerin (OPG) mRNA. However, OPG mRNA expression was higher in gingival tissue associated with teeth affected with FORL than in normal gingival tissue (P<0·05), whereas the reverse was true of RANKL mRNA expression (P<0·05). OPG mRNA expression was significantly higher in teeth than in femoral and alveolar bone (P<0·001). RANKL and OPG mRNAs were detected in all tissues examined. The data suggest that the elevated expression of IL-lβ and IL-6 mRNA plays a role in the mediation of osteoclast activity in advanced FORL. In contrast, OPG and RANKL do not appear to regulate osteoclasts in advanced disease. The results also suggest that OPG and RANKL mRNA play a role in mediating inflammatory responses in gingival cells, and that OPG has an inhibiting effect on tooth resorption.

The purpose of this study was to evaluate the outcome of trabecular metal (TM) acetabular components used in revision hip arthroplasty with major bone deficiency. We retrospectively reviewed the records of 46 patients undergoing revision hip arthroplasty with severe acetabular bone loss. Clinical outcomes were assessed using Harris Hip Score, Western Ontario and McMaster Universities, and Short-Form 12. Mean follow-up was 50 months. All patients had Paprosky type IIc or III acetabular bone deficiency. Major complications included 1 infection, 2 dislocations, and 1 arterial bleeding. Average Harris Hip Score was 78.2. Short-Form 12 scores were within population-based age-matched averages. Western Ontario and McMaster Universities scores were mainly in the 2 lowest disability categories. Porous tantalum shows promising results in revision arthroplasty with severe acetabular bone loss.

To quantify osseous breakdown in multiple myeloma (MM), monoclonal gammopathy of undetermined significance (MGUS), and benign osteoporosis, we measured urinary levels of pyridinium cross-links of collagen in 50 patients with newly diagnosed and untreated MM, 40 patients with MGUS, 40 untreated patients with osteoporotic vertebral fractures, and 64 healthy adults. Ion-paired, reverse-phase high-performance liquid chromatography (HPLC) was used to measure total urinary excretion of pyridinoline (h-PYD) and deoxypyridinoline (h-DPD). Urinary excretion of free immunoreactive deoxypyridinoline (i-DPD) was determined with an enzyme immunoassay. MM patients had significantly (P &lt; .0001) higher levels of h-PYD, h-DPD, and i-DPD than the healthy adults, patients with MGUS, or patients with osteoporosis. The MGUS and osteoporosis groups presented with elevated (P &lt; .05) levels of urinary pyridinium cross-links when compared with healthy controls. In 20 MM patients who subsequently recei...

A follow-up of disc herniation (herniated nucleus pulposus [HNP]) resorption on magnetic resonance imaging (MRI). To assess the determinants of resorption of HNP. Neovascularization in the outermost areas of HNP, presenting as an enhancing rim in gadolinium diethylenetriamine pentaacetic acid MR images, is thought to be a major determinant of spontaneous resorption of HNP. Patients with HNP-induced sciatica at baseline were rescanned at 2 months (N = 74) and after 12 months (N = 53). The volume of HNP (mm), thickness (mm) and extent (%) of enhancement, and the degree of HNP migration (Komori classification) were analyzed. Repeated measures analysis of covariance was used in statistical analysis. Significant resorption of HNP occurred from baseline to 2 months, although the resorption rate was more pronounced over the whole 1-year follow-up. Higher baseline scores of rim enhancement thickness, higher degree of HNP displacement in the Komori classification, and age category 41-50 year...