Alendronate induces mineralization in mouse osteoblastic MC3T3-E1 cells: regulation of mineralization-related genes.

Alendronate, an aminobisphosphonate, is an effective reagent to reduce fracture risk in osteoporotic patients. Although several studies suggest that bisphosphonates affect osteoblast differentiation, how they affect the genes relating to the mineralization step remains unknown. The present study was performed to clarify the effects of alendronate on mineralization and its related genes in mouse osteoblastic MC3T3-E1 cells. Alendronate at 10 (-8) and 10 (-7) M induced mineralization in MC3T3-E1 cells. As for the genes that suppress mineralization, alendronate enhanced the level of PC-1 mRNA in a dose-dependent manner in 7-day cultures in semiquantitative RT-PCR, although it reduced the levels of PC-1 mRNA in 21-day cultures. On the other hand, alendronate did not affect the levels of ANK, osteopontin and matrix Gla protein mRNA in both 7- and 21-day cultures. Moreover, alendronate reduced the level of osteocalcin mRNA at 10 (-7) and 10 (-6) M in 14-day cultures of these cells. As for the expression of alkaline phosphatase (ALP), an important positive regulator of mineralization in osteoblasts, alendronate enhanced the levels of ALP mRNA and protein at 10 (-7)-10 (-5) M. In conclusion, low-dose alendronate induced mineralization in mouse osteoblastic cells. The regulation of PC-1, osteocalcin and ALP by alendronate might play some role in these effects.

Low density lipoprotein-cholesterol levels affect vertebral fracture risk in female patients with primary hyperparathyroidism.

Although increased arterial sclerosis and dyslipidemia were observed in primary hyperparathyroidism (pHPT) patients in previous studies, it still remains unclear about the relationships between lipid and bone metabolism in pHPT patients, especially about fracture risk. The present study was performed to examine the relationships between lipid metabolism parameters including body composition and bone metabolism in 116 female patients with pHPT and 116 age-matched control subjects. Bone mineral density (BMD) and body composition were measured by dual-energy x-ray absorptiometry. Serum low density lipoprotein (LDL)-cholesterol (Chol) levels were negatively related to only z-score of BMD at femoral neck and serum creatinine levels. Serum levels of LDL-Chol were significantly lower in the group with vertebral fractures in pHPT patients, although body composition parameters were not significantly different. In univariate logistic regression analyses, age, height, BMD at lumbar spine and radius, serum levels of creatinine, total-Chol and LDL-Chol were significantly selected as a predictor of vertebral fractures. LDL-Chol was related to vertebral fractures independently of the other parameters. In conclusion, the present study demonstrated that lower serum LDL-Chol levels were related to vertebral fracture risk independent of renal function, age, body size, bone metabolism parameters and the severity of the disease in pHPT women.

Parapharyngeal meningioma extending from the intracranial space.

A 50-year old woman with a giant parapharyngeal meningioma extending from the intracranial cavity was admitted to our hospital. The parapharyngeal tumor was biopsied using the transoral approach and a histological section diagnosis suggested meningioma. Thereafter, further examination by magnetic resonance images (MRI) and contrast enhanced CT scans revealed a diffuse meningioma en plaque in the posterior fossa. Invasion extended from the clival dura to the right sigmoid sinus. The extracranial extension of a meningioma is very rare but a few cases have been reported. In almost all of the reported cases, a large intracranial meningioma was simultaneously or previously verified by CT scans. Our case was special in that the intracranial mass was not voluminous but showed en plaque extension, and also because the pathway of the extracranial extension through the jugular foramen was clearly visualized by CT and MRI. Obliteration and invasion of the right sigmoid sinus and the internal jugular vein by tumor were also demonstrated.