Vitamin B-12 deficiency stimulates osteoclastogenesis via increased homocysteine and methylmalonic acid

The risk of nutrient deficiencies increases with age in our modern Western society, and vitamin B(12) deficiency is especially prevalent in the elderly and causes increased homocysteine (Hcy) and methylmalonic acid (MMA) levels. These three factors have been recognized as risk factors for reduced bone mineral density and increased fracture risk, though mechanistic evidence is still lacking. In the present study, we investigated the influence of B(12), Hcy, and MMA on differentiation and activity of bone cells. B(12) deficiency did not affect the onset of osteoblast differentiation, maturation, matrix mineralization, or adipocyte differentiation from human mesenchymal stem cells (hMSCs). B(12) deficiency caused an increase in the secretion of Hcy and MMA into the culture medium by osteoblasts, but Hcy and MMA appeared to have no effect on hMSC osteoblast differentiation. We further studied the effect of B(12), Hcy, and MMA on the formation of multinucleated tartrate-resistant acid phosphatase-positive osteoclasts from mouse bone marrow. We observed that B(12) did not show an effect on osteoclastogenesis. However, Hcy as well as MMA were found to induce osteoclastogenesis in a dose-dependent manner. On the basis of these results, we conclude that B(12) deficiency may lead to decreased bone mass by increased osteoclast formation due to increased MMA and Hcy levels

Evaluation of multiway frequencies tables by log-linear modeling and an example

Medical and health policy research data me often most informative when presented as a multidimensionally cross-classified table of counts. Most researchers analyze multidimensional contingency tables by studying two or more variables at a time using chi(2) statistics. Although such an approach often gives great insight about the relationship among variables, it has its limitations. Hence, the log-linear models are suggested

The nature of pre-­‐service science teachers’ argumentation in inquiry-­‐oriented laboratory context

The aim of this study was to investigate the kinds of argumentation schemes generated by pre-service elementary science teachers (PSTs) as they perform inquiry-oriented laboratory tasks, and to explore how argumentation schemes vary by task as well as by experimentation and discussion sessions. The model of argumentative and scientific inquiry was used as a design framework in the present study. According to the model, the inquiry of scientific topics was employed by groups of participants through experimentation and critical discussion sessions. The participants of the study were 35 PSTs, who teach middle school science to sixth through eighth grade students after graduation. The data were collected through video- and audio-recordings of the discussions made by PSTs in six inquiry-oriented laboratory sessions. For the analysis of data, pre-determined argumentation schemes by Walton were employed. The results illustrated that PSTs applied varied premises rather than only observations or reliable sources to ground their claims or to argue for a case or an action. It is also worthy of notice that the construction and evaluation of scientific knowledge claims resulted in different numbers and kinds of arguments. Results of this study suggest that designing inquiry-oriented laboratory environments, which are enriched with critical discussion, provides discourse opportunities that can support argumentation. Moreover, PSTs can be encouraged to support and promote argumentation in their future science classrooms if they engage in argumentation integrated instructional strategies

Effect of a Cholesterol Rich Diet, Recurrent Infection and Possible Treatment Modalities on the Pulmonary Vascular System: An Experimental Study

Objective: Infection may lead to inflammation, atherosclerosis and thrombotic vascular events. The atherosclerotic effect of hypercholesterolaemia on the vascular system is well-known. However, limited studies were done on the therapeutic and preventative agents. The aim of this study was to investigate the effects of infection and cholesterol rich diet combined with an antibiotic, anti-inflammatory agent and red wine on the pulmonary vascular system. Methods: Fifty-nine rats were evaluated. Six groups were created: Control-Group I (n = 10); infection – Group II (n = 9), infection-cholesterol rich diet – Group III (n = 12), infection-cholesterol rich diet-cefepime – Group IV (n = 11); infection-cholesterol rich diet-diclofenac potassium – Group V (n = 9); infection-cholesterol rich diet and red wine – Group VI (n = 8). Blood samples of rats were collected for cholesterol analysis every month. Sections of central pulmonary arteries were examined for thickness of the intima and medial wall by computerised image analysis. Results: There was a statistically significant difference in serum cholesterol levels and in thickness of the intima between the groups (p = 0.000). The rest of the groups had more intimal thickening than Group I (p = 0.000). Group III had thicker intima than Groups IV and V (p = 0.009, p = 0.011 respectively). There was no significant difference between the groups in thickness of media (p = 0.432). Conclusion: Infection and cholesterol rich diet have a synergistic effect on atherosclerosis in pulmonary arteries. However, antibiotics and anti-inflammatory agents could be useful in prevention. Key Words: Atherosclerosis, cefepime, diclofenac potassium, pulmonary artery, red wine "Efecto de la dieta Rica en Colesterol, la Infección Recurrente, y las Posibles Modalidades de Tratamiento Sobre el Sistema Vascular Pulmonar: un Estudio Experimental" RESUMEN Objetivo: La infección puede conducir a inflamación, ateroesclerosis y eventos vasculares trombóticos. El efecto aterosclerótico de la hipercolesterolemia en el sistema vascular es bien conocido. Sin embargo, se hicieron estudios limitados sobre los agentes preventivos y terapéuticos. El objetivo de este estudio fue investigar los efectos de la infección y la dieta rica en colesterol, combinados con agentes antibióticos, anti-inflamatorios, y vino tinto, sobre el sistema vascular pulmonar. Métodos: Cincuenta y nueve ratas fueron evaluadas. Se hicieron seis grupos: grupo-control I (n = 10), grupo-infección II (n = 9), grupo infección-dieta rica en colesterol III (n = 12), grupo-infección-dieta rica en colesterol-cefepima IV (n = 11), grupo-infección-dieta rica en colesterol-diclofenaco potásico V (n = 9), grupo-infección-dieta rica en –vino tinto VI (n = 8). Se tomaron muestras de sangre de ratas para analizar el colesterol cada mes. Se examinaron secciones de las arterias pulmonares centrales para determinar el grosor de la pared íntima y media mediante análisis computarizado de imágenes. Resultados: Hubo una diferencia estadísticamente significativa en los niveles de colesterol en suero y el grosor de la íntima entre los grupos (p = 0.000). El resto de los grupos tenía más engrosamiento de la íntima que el grupo I (p = 0.000). El grupo III tenía una íntima más gruesa que los grupos IV y V (p = 0,009, p = 0.011 respectivamente). No hubo ninguna diferencia significativa entre los grupos en cuanto al espesor de la media (p = 0.432). Conclusión: La infección y la dieta rica en colesterol tienen un efecto sinérgico sobre la aterosclerosis en las arterias pulmonares. Sin embargo, los antibióticos y los agentes antiinflamatorios podrían ser útiles para la prevención. Palabras claves: Aterosclerosis, cefepima, diclofenaco potásico, arteria pulmonar, vino tinto