Thyroid,parathyroid hormones and calcium homeostasis

The thyroid gland secretes thyroxine (T4) and triiodothyronine (T3) in response to thyroid-stimulating hormone (TSH) released from the anterior pituitary gland. Iodine is essential for the synthesis of thyroid hormones. T4 and T3 increase basal metabolic rate, heat production and help to maintain normal growth and development. The parathyroid glands are essential for maintaining normal levels of serum calcium, which is necessary to maintain normal cellular function via calcium acting as a secondary messenger. Calcium is also involved in the coagulation of blood, transmission of nerve impulses and muscular contraction. Calcium is provided by various dietary sources and plasma levels are altered by varying absorption in the gut, mobilization from bone and excretion by the kidney.     

颅内动脉粥样硬化与绝经后女性骨密度相关性研究

目的观察颅内动脉粥样硬化与绝经后女性骨密度(bone mineral density,BMD)相关性。方法研究人群包括100名绝经后妇女,对受试者进行腰椎双能X线扫描,通过脑三维磁共振血管造影来评估受试者基底动脉、中脑、颅内颈内动脉和颅内椎动脉的粥样硬化情况。T值-1被定义为低骨量。所有分析均通过颅内动脉粥样硬化定位分层。结果 100名绝经后女性年龄范围为55～75岁。颅内动脉粥样硬化中颅内后循环(PC)动脉和颅内前循环(AC)动脉患病率分别为64%和67%。颅内动脉粥样硬化中AC与女性患者的低BMD相关。颅内动脉粥样硬化中PC的女性血磷水平显著升高,而T值显著低于颅内动脉粥样硬化中无PC的女性,高脂血症和低BMD在PC颅内动脉粥样硬化女性中更为常见,低BMD与PC中的颅内动脉粥样硬化显著相关。结论低BMD与女性亚临床颅内PC和AC动脉粥样硬化有关。     

The investigation of non‐invasive techniques for treating early approximal carious lesions: an in vivo study

Objectives: The aim of this study was to examine non‐cavitated approximal caries using non‐invasive treatment methods. Materials and methods : Molar and premolar teeth with approximal caries were used in this in vivo study. Approximal caries lesions were evaluated with visual and radiographic inspection and with the DIAGNOdent device. Five groups were formed to study non‐invasive treatment, and each had at least 25 early approximal carious lesions. Patients in the control group were not treated. After the separation, either ozone application, acidulated phosphate fluoride gel, CPP‐ACP‐containing material (Tooth Mousse), or an antibacterial bonding agent (Clearfil Protect Bond) was used. For 18 months after the non‐invasive treatment, radiological controls were used to observe the progress of the initial and approximal caries in the 1st, 3rd, 6th and 12th months of follow‐up. A Mann–Whitney U‐test was used to perform the statistical analysis; in‐group comparisons were made with the Wilcoxon signed‐rank test, and a quantitative assessment was performed using a chi‐squared test. Results: At the end of 18 months, the caries lesions in the control group were observed to progress (P < 0.01). The lesions that were scored as 1a during a visual inspection recovered by using non‐invasive treatments. Conclusion: Approximal caries lesions that were detected at the early stages remained stationary when using antibacterial agents and materials that promoted remineralisation. Clinical relevance: Antibacterial agents and remineralisation materials can be used in treatment of early approximal caries lesions.     

State of the art and future directions of scaffold-based bone engineering from a biomaterials perspective

Scaffold-based bone tissue engineering aims to repair/regenerate bone defects. Such a treatment concept involves seeding autologous osteogenic cells throughout a biodegradable scaffold to create a scaffold-cell hybrid that may be called a tissue-engineered construct (TEC). A variety of materials and scaffolding fabrication techniques for bone tissue engineering have been investigated over the past two decades. This review aims to discuss the advances in bone engineering from a scaffold material point of view. In the first part the reader is introduced to the basic principles of bone engineering. The important properties of the biomaterials and the scaffold design in the making of tissue engineered bone constructs are discussed in detail, with special emphasis placed on the new material developments, namely composites made of synthetic polymers and calcium phosphates. Advantages and limitations of these materials are analysed along with various architectural parameters of scaffolds important for bone tissue engineering, e.g. porosity, pore size, interconnectivity and pore-wall microstructures.     

PMMA骨水泥与磷酸钙骨水泥诱导成膜及其对成骨活性的差异

目的 比较PMMA骨水泥与磷酸钙骨水泥诱导周围形成膜的结构和成骨活性的差异.方法 32只健康成年新西兰大白兔按照随机数字表法分为PMMA组和磷酸钙组,每组16只,双侧桡骨制造15 mm骨缺损,分别植入PMMA和磷酸钙骨水泥,4、6周后每组选取2只兔子取出骨水泥周围包裹的诱导膜比较膜厚度及血管密度;第4周取出骨水泥并在膜内植入自体松质骨,植骨后8、12周分别通过放射学和组织学评估新生骨形成的情况.结果 ①4、6周时PMMA骨水泥组诱导形成的膜厚度分别为(1 108 ±26)、(945±42) μm,磷酸钙骨水泥组诱导成膜厚度为(945 ±34)、(778±22) μm,两组间差异有统计学意义(P＜0.05).PMMA骨水泥诱导的膜血管密度分别为6、3个/cm2,而磷酸钙骨水泥诱导形成的膜血管密度分别为2、2个/cm2.②放射学检测可见植骨后第8、12周PMMA组成骨按Lane-Sandhu X线评分(2.84 ±0.36)、(4.22±0.54)优于磷酸钙组(1.98 ±0.15)、(3.16 ±0.23),两组间差异有统计学意义(P＜0.05).③第8、12周组织学观察PMMA组按Nilsson组织学评分标准进行评分(3.14 ±0.29)、(4.63 ±0.37),成骨优于磷酸钙组(2.10 ±0.18)、(3.59±0.21),两组间差异有统计学意义(P＜0.05).结论 在新西兰兔桡骨骨缺损处PMMA骨水泥诱导形成的生物膜较磷酸钙骨水泥诱导形成的生物膜具有更强的促血管化和成骨活性.     

酪蛋白磷酸多肽-无定形磷酸钙对固定正畸所致牙釉质脱矿的影响

研究酪蛋白磷酸多肽-无定形磷酸钙（商品名GC护牙素）对固定正畸所致牙釉质脱矿的影响。选择固定正畸治疗患者40例,经签字同意进入实验。以随机数字表法随机分为对照组、实验组各20例。对照组在口腔卫生宣教的基础上采用单纯口腔卫生措施,实验组在对照组的基础上使用GC护牙素。2组患者从治疗开始,进行连续13个月的牙〖XCz1.tif,JZ〗照片观察。观测指标为牙面是否有新出现的的白垩色斑片或龋洞,统计并计算牙釉质脱矿率及脱矿指数（EDI）。（1）对照组、实验组的牙釉质脱矿率均随着时间的增加而增高;（2）对照组EDI高于实验组。在口腔卫生措施的基础上使用GC护牙素预防固定正畸所致牙釉质脱矿是一种安全有效的措施。     

川芎嗪抗肝纤维化作用的实验研究

目的:观察川芎嗪的抗肝纤维化作用。方法:用50％四氯化碳油剂腹腔注射6周诱导大鼠肝纤维化模型并用川芎嗪治疗,观察其对肝纤维化各项指标的影响。结果:川芎嗪能显著降低大鼠血清谷丙转氨酶(ALT)、丙二醛(MDA)、透明质酸(HA)、Ⅲ型前胶原(PCⅢ)及肝组织中MDA;提高肝组织中超氧化物歧化酶(SOD)活性;显著减轻肝脏胶原纤维增生程度。结论:川芎嗪有抗脂质过氧化作用及抗肝纤维化作用。     

Toxicology of 3-epi-deoxynivalenol,a deoxynivalenol-transformation product by Devosia mutans 17-2-E-8

Microbial detoxification of deoxynivalenol (DON) represents a new approach to treating DON-contaminated grains. A bacterium Devosia mutans 17-2-E-8 was capable of completely transforming DON into a major product 3-epi-DON and a minor product 3-keto-DON. Evaluation of toxicities of these DON-transformation products is an important part of hazard characterization prior to commercialization of the biotransformation application. Cytotoxicities of the products were demonstrated by two assays: a MTT bioassay assessing cell viability and a BrdU assay assessing DNA synthesis. Compared with DON, the IC₅₀ values of 3-epi-DON and 3-keto-DON were respectively 357 and 3.03 times higher in the MTT bioassay, and were respectively 1181 and 4.54 times higher in the BrdU bioassay. Toxicological effects of 14-day oral exposure of the B6C3F₁ mouse to DON and 3-epi-DON were also investigated. Overall, there were no differences between the control (free of toxin) and the 25 mg/kg bw/day or 100 mg/kg bw/day 3-epi-DON treatments in body and organ weights, hematology and organ histopathology. However, in mice exposed to DON (2 mg/kg bw/day), white blood cell numbers and serum immunoglobulin levels were altered relative to controls, and lesions were observed in adrenals, thymus, stomach, spleen and colon. Taken together, in vitro and in vivo studies indicate that 3-epi-DON is substantially less toxic than DON.     

Toxic trace elements at gastrointestinal level

Many trace elements are considered essential [iron (Fe), zinc (Zn), copper (Cu)], whereas others may be harmful [lead (Pb), cadmium (Cd), mercury (Hg), arsenic (As)], depending on their concentration and chemical form. In most cases, the diet is the main pathway by which they enter our organism. The presence of toxic trace elements in food has been known for a long time, and many of the food matrices that carry them have been identified. This has led to the appearance of legislation and recommendations concerning consumption. Given that the main route of exposure is oral, passage through the gastrointestinal tract plays a fundamental role in their entry into the organism, where they exert their toxic effect. Although the digestive system can be considered to be of crucial importance in their toxicity, in most cases we do not know the events that occur during the passage of these elements through the gastrointestinal tract and of ascertaining whether they may have some kind of toxic effect on it. The aim of this review is to summarize available information on this subject, concentrating on the toxic trace elements that are of greatest interest for organizations concerned with food safety and health: Pb, Cd, Hg and As.     

Advances in pharmacotherapy for hyperphosphatemia in renal disease

Introduction: Hyperphosphatemia in chronic kidney disease (CKD) is considered as an independent risk factor for surrogate clinical end points like vascular calcification (VC) and bone disease, or hard clinical outcomes like cardiovascular events. Various treatment options are available for phosphate removal or reduction. Calcium-based phosphate binders (CBB) with their possible positive calcium balance became culprits for progressive VC and increased mortality risk. Non-calcium-based binders (NCBB) treatment allowed a comparable control of hyperphosphatemia with a lower risk of hypercalcemia and a slower progression of VC. Recent data have shown a 22% risk reduction in all-cause mortality with NCBB compared to CBB treatment. The appropriate timing of phosphate binder initiation in CKD patients is still unclear. Recent reports in patients with CKD stages 3b-4 showed increased VC progression when actively treated compared to placebo and a positive calcium, but no negative phosphate balance.

Areas covered: This review discusses the advantages and disadvantages of the pharmacological options to treat hyperphosphatemia.

Expert opinion: The use of phosphate binders is essential in preventing morbidity and mortality in dialysis patients. The choice of phosphate binder takes into account CKD stage, the presence of other components of CKD-mineral and bone disorders, concomitant therapies and drug side-effect profile.