This book explores whether the world economy is breaking up into regional trading and currency blocs centred on the European Community, Japan and the United States. Frankel uses trade, investment and financial data to assess this issue. He concludes with an analysis of how trends in regional economic integration can be used as building blocks for a stronger multilateral system.

Regional Trading Blocs in the world economic system, reseñado por Antonio Ortiz-Mena L.N.

Therefore, the seeker after the truth is not one who studies the writings of the ancients and, following his natural disposition, puts his trust in them, but rather the one who suspects his faith in them and questions what he gathers from them, the one who submits to argument and demonstration, and not to the sayings of a human being whose nature is fraught with all kinds of imperfection and de‹ciency. Thus the duty of the man who investigates the writings of scientists, if learning the truth is his goal, is to make himself the enemy of all that he reads, and, applying his mind to the core and margins of its content, attack it from every side. He should also suspect himself as he performs his critical examination of it, so that he may avoid falling into either prejudice or leniency. (Ibn al-Haytham)1

국제정치이론 = Theory of international politics

Nonsteroidal anti-inflammatory drugs (NSAIDs) play an essential part in our approach to control pain in the posttraumatic setting. Over the last decades, several studies suggested that NSAIDs interfere with bone healing while others contradict these findings. Although their analgesic potency is well proven, clinicians remain puzzled over the potential safety issues. We have systematically reviewed the available literature, analyzing and presenting the available in vitro animal and clinical studies on this field. Our comprehensive review reveals the great diversity of the presented data in all groups of studies. Animal and in vitro studies present so conflicting data that even studies with identical parameters have opposing results. Basic science research defining the exact mechanism with which NSAIDs could interfere with bone cells and also the conduction of well-randomized prospective clinical trials are warranted. In the absence of robust clinical or scientific evidence, clinicians should treat NSAIDs as a risk factor for bone healing impairment, and their administration should be avoided in high-risk patients.

/pdf/do-nonsteroidal-anti-inflammatory-drugs-affect-bone-healing-1fepk9koso.pdf

Do Nonsteroidal Anti-Inflammatory Drugs Affect Bone Healing? A Critical Analysis

Osteocytes, the most abundant cells in bone, have been long postulated to detect and respond to mechanical and hormonal stimuli and to coordinate the function of osteoblasts and osteoclasts. The discovery that the inhibitor of bone formation sclerostin is primarily expressed in osteocytes in bone and downregulated by anabolic stimuli provided a mechanism by which osteocytes influence the activity of osteoblasts. Advances of the last few years provided experimental evidence demonstrating that osteocytes also participate in the recruitment of osteoclasts and the initiation of bone remodeling. Apoptotic osteocytes trigger yet-to-be-identified signals that attract osteoclast precursors to specific areas of bone, which in turn differentiate to mature, bone-resorbing osteoclasts. Osteocytes are also the source of molecules that regulate the generation and activity of osteoclasts, such as OPG and RANKL; and genetic manipulations of the mouse genome leading to loss or gain of function or to altered expression of either molecule in osteocytes markedly affect bone resorption. This review highlights these investigations and discusses how the novel concept of osteocyte-driven bone resorption and formation impacts our understanding of the mechanisms by which current therapies control bone remodeling.

Osteocyte-Driven Bone Remodeling

Dental implants in the medically compromised patient.

The purpose of this study was to evaluate the effects of simvastatin on guided bone regeneration in the mandibles of ovariectomized rats, and to observe their blood cholesterol levels. Seventy female rats were divided into two groups: control and treated, both groups containing normal and ovariectomized rats. A month after ovariectomy a bone defect was created in the mandible, and was covered by a polytetrafluoroethylene membrane. The treated groups received simvastatin orally for 15 or 30 days. The rats were sacrificed 15, 30 or 60 days after surgery, at which time a blood sample was extracted for blood cholesterol level analysis and the mandible was extracted for densitometric, histological and morphometric analysis. All specimens underwent analysis of variance. The ovariectomized animals had higher cholesterol levels than the treated normal animals, and no significant difference was found between the different treatment periods and the sacrifice times. The densitometric, histological and morphometric analysis showed that the treated ovariectomized animals developed more new bone than the control ovariectomized rats, but no significant difference was observed between the treatment periods. It can be concluded that the deficiency of estrogen increased the level of blood cholesterol and that the simvastatin aided new bone formation in the ovariectomized animals.

Effects of simvastatin on bone regeneration in the mandibles of ovariectomized rats and on blood cholesterol levels.

Bisphosphonates are currently used in the treatment of many diseases involving increased bone resorption such as osteoporosis. Statins have been widely used for the treatment of hypercholesterolemia and recent studies have shown that these drugs are also capable of stimulating bone formation. The purpose of this study was to evaluate the influence of an estrogen deficient state and the effects of simvastatin and sodium alendronate therapies on alveolar bone in female rats. Fifty-four rats were either ovariectomized (OVX) or sham operated. A month later, the animals began to receive a daily dose of simvastatin (SIN - 25 mg/kg), sodium alendronate (ALN - 2 mg/kg) or water (control) orally. Thirty-five days after the beginning of the treatment, the rats were sacrificed and their left hemimandibles were removed and radiographed using digital X-ray equipment. The alveolar radiographic density under the first molar was determined with gray-level scaling and the values were submitted to analysis of variance (alpha = 5%). Ovariectomized rats gained more weight (mean +/- standard deviation: 20.06 +/- 6.68%) than did the sham operated animals (12.13 +/- 5.63%). Alveolar radiographic density values, expressed as gray levels, were lowest in the OVX-water group (183.49 +/- 6.47), and differed significantly from those observed for the groups receiving alendronate (sham-ALN: 193.85 +/- 3.81; OVX-ALN: 196.06 +/- 5.11) and from those of the sham-water group (193.66 +/- 4.36). Other comparisons between groups did not show significant differences. It was concluded that the ovariectomy reduced alveolar bone density and that alendronate was efficient for the treatment of this condition.

/pdf/the-influence-of-ovariectomy-simvastatin-and-sodium-3uun6jxlor.pdf

The influence of ovariectomy, simvastatin and sodium alendronate on alveolar bone in rats.

Bisphosphonates are currently used in the treatment of many diseases involv- ing increased bone resorption such as osteoporosis. Statins have been widely used for the treatment of hypercholesterolemia and recent studies have shown that these drugs are also capable of stimulating bone formation. The purpose of this study was to evaluate the influence of an estrogen deficient state and the effects of simvastatin and sodium alendro - nate therapies on alveolar bone in female rats. Fifty-four rats were either ovariectomized (OVX) or sham operated. A month later, the animals began to receive a daily dose of sim- vastatin (SIN - 25 mg/kg), sodium alendronate (ALN - 2 mg/kg) or water (control) orally. Thirty-five days after the beginning of the treatment, the rats were sacrificed and their left hemimandibles were removed and radiographed using digital X-ray equipment. The alveolar radiographic density under the first molar was determined with gray-level scal - ing and the values were submitted to analysis of variance (α = 5%). Ovariectomized rats gained more weight (mean ± standard deviation: 20.06 ± 6.68%) than did the sham oper- ated animals (12.13 ± 5.63%). Alveolar radiographic density values, expressed as gray lev- els, were lowest in the OVX-water group (183.49 ± 6.47), and differed significantly from those observed for the groups receiving alendronate (sham-ALN: 193.85 ± 3.81; OVX- ALN: 196.06 ± 5.11) and from those of the sham-water group (193.66 ± 4.36). Other comparisons between groups did not show significant differences. It was concluded that the ovariectomy reduced alveolar bone density and that alendronate was efficient for the treatment of this condition. Descriptors: Alendronate; Models, animal; Osteoporosis; Ovariectomy; Simvastatin.

/pdf/the-influence-of-ovariectomy-simvastatin-and-sodium-2o49081j7u.pdf

The influence of ovariectomy, simvastatin and sodium alendronate on alveolar bone in rats Influência da ovariectomia, da sinvastatina e do alendronato sódico no osso alveolar em ratas

Alcohol consumption is a risk indicator for periodontal disease. The purpose of this study was to morphometrically evaluate the influence of alcohol consumption on alveolar bone level associated with ligature-induced periodontitis in rats. Thirty-six female rats (Wistar, 120 days-old) were randomly divided into three groups that received a daily administration of a water diet (control, n = 12), a 10% alcohol diet (10% ethanol, n = 12) or a 20% alcohol diet (20% ethanol, n = 12). Four weeks after the onset of the experiment, cotton ligatures were placed around the cervix of the upper right second molar in six rats. The other 6 rats in each group remained unligated. The rats were sacrificed four weeks after ligature placement. The maxillary bones were removed and alveolar bone loss was analyzed by measuring the distance between the cementoenamel junction and the alveolar bone crest at 2 buccal and 2 palatal sites on the upper right second molar. Analyses between the ligated and unligated groups showed that the presence of ligature induced alveolar bone loss (p 0.05). In the ligated groups, rats receiving 20% ethanol showed significantly greater bone loss compared to control rats or rats receiving 10% ethanol. These results demonstrate that alcohol consumption may increase alveolar bone loss in female rats in a dose-dependent manner.

http://www.scielo.br/pdf/bor/v23n3/17.pdf

Influence of alcohol consumption on alveolar bone level associated with ligature-induced periodontitis in rats

Summary
The aim of the present study was to determine the action of AsGA laser irradiation on bone repair in the tibia of osteopenic rats. The animals were randomly divided into eight experimental groups according to the presence of ovarian hormone (sham group) or the absence of the hormone (OVX group), as well as being irradiated or non-irradiated. Low-level 904-nm laser (50 mJ/cm2) accelerated the repair process of osteopenic fractures, especially in the initial phase of bone regeneration.

Rosilene Fernandes da Rocha

Papers

Effects of simvastatin on bone regeneration in the mandibles of ovariectomized rats and on blood cholesterol levels.

The influence of ovariectomy, simvastatin and sodium alendronate on alveolar bone in rats.

The influence of ovariectomy, simvastatin and sodium alendronate on alveolar bone in rats Influência da ovariectomia, da sinvastatina e do alendronato sódico no osso alveolar em ratas

Influence of alcohol consumption on alveolar bone level associated with ligature-induced periodontitis in rats

Laser 904 nm action on bone repair in rats with osteoporosis.