自固化磷酸钙人工骨体内植入长期实验研究

目的：自固化磷酸钙（CPC）是新型的非陶瓷型羟基磷灰石类人工骨材料。本文观察了CPC植入体内的实验结果。方法：将术中预制成形的CPC植入兔股骨髁处缺损和肌肉内，观察18个月。结果：CPC只引起一过性的炎症反应，与骨直接愈合。12个月时CPC降解约12％，18个月时约为19％，降解处由骨组织替代。CPC与骨为界面结合，CPC的降解为溶解降解，是两个重要发现。结论：CPC适合于非负重或低负重部位骨缺损的修复。     

改良式微推出试验评价化学处理玻璃纤维桩表面后与树脂水门汀的粘接强度

目的:建立一种改良式微推出方式测试玻璃纤维桩表面经35%磷酸+硅烷偶联剂处理后与树脂水门汀的粘接强度,探讨此种测试模式评价玻璃纤维桩与树脂水门汀粘接强度的价值。方法:先将40支玻璃纤维桩随机分成2大组,每组20支,组1为磷酸+硅烷化组,组2为对照组。再将每一大组随机分为M(改良)和T(传统)两个小组,每组10支,分别用改良式微推出试验和传统微推出试验测定纤维桩与树脂水门汀的粘接强度并观察破坏模式。结果:组1M(磷酸+硅烷化组-改良)微推出粘接强度为(18.85±1.42) MPa,组1T(磷酸+硅烷化组-传统)为(19.39±1.35) MPa,组2M(对照组-改良)为(11.26±1.57)MPa,组2T(对照组-传统)为(11.27±1.83)MPa,在改良组和传统组中,磷酸+硅烷化组粘接强度值均显著高于对照组(P<0.01),且改良组中断裂模式100%为桩/树脂界面破坏,相比传统组的65.7%,更加集中体现界面粘接强度的变化。结论:相较于传统组,改良组微推出试验能更有效地评价纤维桩与树脂水门汀之间的粘接强度,且35%磷酸+硅烷化处理玻璃纤维桩表面可以更有效地提高其与树脂水门汀的粘接强度。     

Hyperphosphatemia in children receiving peritoneal dialysis—an educational program

Hyperphosphatemia has been associated with the development of secondary hyperparathyroidism, renal osteodystrophy, cardiovascular calcification and increased risk of death. Using a one group, pretest-posttest study design, we sought to evaluate changes in serum phosphorus, calcium, parathyroid hormone and subject knowledge in response to a 3-month educational intervention. Mean serum phosphorus levels did not differ significantly between the three evaluation periods: pretreatment (5.69 mg/dl), treatment (5.84 mg/dl) and posttreatment (6.17 mg/dl). Mean serum calcium, calcium-phosphorus product and PTH values also did not differ significantly between the treatment periods. We observed no difference between the subject test scores between the two testing periods. Calcium-phosphorus product, serum phosphorus and PTH values on average, despite the education program, remained outside the K/DOQI target guidelines 44, 56 and 81% of the time, respectively. The results of this study suggest that an aggressive 3-month patient education program targeting dietary phosphorus knowledge, phosphate binder name and dosing, and knowledge of medical consequences associated with non-compliance had no effect on the serum phosphorus, calcium, PTH or phosphate binder need.     

磷酸缓冲盐(PBS)片剂的研制

目的:为使缓冲盐这类常用试剂的配制过程简便.方法:制成缓冲盐片剂,分析比较片剂配制成的缓冲液与散剂配制的缓冲液的特性和作用.结果:两者具有同样的特性和作用.结论:此项研究为把PBS这类试剂制成片剂使用提供了依据.     

磷酸瑞格列汀片在肾功能不全受试者的药代动力学研究

目的 通过比较磷酸瑞格列汀片在不同程度肾功能不全患者与肾功能正常受试者的药代动力学差异,为制定肾功能不全患者的临床应用方案提供依据。方法 32例受试者按肌酐清除率（Ccr）分入轻(60~89 mL/min)、中(30~59 mL/min)、重度肾功能不全(15~29 mL/min)组、终末期肾病(Cmax）,SP2086吸收入血后,迅速转化为主要活性代谢产物SP2086酸。轻度、中度、重度和终末期肾病组与正常肾功能组相比,SP2086和SP2086酸的Cmax和曲线下面积（AUC）逐渐增加;轻度、中度、重度和终末期肾病组SP2086和SP2086酸Tmax逐渐增加。轻、中、重度肾功能不全组、终末期肾病组以及正常肾功能组SP2086酸清除率（CL/F）分别为（23.50±6.01）、（12.90±4.34）、（6.71±1.55）、（3.06±0.48）和（30.50±10.70） L/h,SP2086酸0~96 h Ae%分别为（71.7±14.3）%、（59.5±22.7）%、（63.3±13.9）%、（34.1±20.0）%和（74.2±14.6）%,CLR分别为(220.0±51.2)、(105.0±64.5)、(54.5±7.6)、(13.5±7.8)和(289.0±73.7) mL/min。各组SP2086 0~96 h尿液累积排泄百分率（Ae%）平均为0.441%～4.530%。随着肾功能损害程度加重,SP2086和SP2086酸的CL/F明显递减,与正常肾功能组比,中度肾功能不全组的AUC0-∞为其1.44倍和2.32倍,重度肾功能不全组的AUC0-∞为其2.20倍和4.39倍,终末期肾病组的AUC0-∞为其2.83倍和9.28倍。结论 正常肾功能患者磷酸瑞格列汀片的临床推荐剂量为100 mg/d,本研究结果推荐轻度肾功能不全患者无需调整剂量;中度肾功能不全患者减至50 mg/d;重度肾功能不全患者减至25 mg/d;而终末期肾病患者不推荐使用磷酸瑞格列汀。     

Brain energy metabolism during hypoglycaemia in healthy and Type 1 diabetic subjects

Aims/hypothesis This study aimed to examine brain energy metabolism during moderate insulin-induced hypoglycaemia in Type 1 diabetic patients and healthy volunteers.Methods Type 1 diabetic patients (mean diabetes duration 13±2.5 years; HbA₁c 6.8±0.3%) and matched controls were studied before, during (0–120 min) and after (120–240 min) hypoglycaemic (~3.0 mmol/l) hyperinsulinaemic (1.5 mU·kg^–1·min^–1) clamp tests. Brain energy metabolism was assessed by in vivo ³¹P nuclear magnetic resonance spectroscopy of the occipital lobe (3 Tesla, 10-cm surface coil).Results During hypoglycaemia, the diabetic patients showed blunted endocrine counter-regulation. Throughout the study, the phosphocreatine:-ATP ratios were lower in the diabetic patients (baseline: controls 3.08±0.29 vs diabetic patients 2.65±0.43, p<0.01; hypoglycaemia: 2.97±0.38 vs 2.60±0.35, p<0.05; recovery: 3.01±0.28 vs 2.60±0.35, p<0.01). Intracellular pH increased in both groups, being higher in diabetic patients (7.096±0.010 vs. 7.107±0.015, p<0.04), whereas intracellular magnesium concentrations decreased in both groups (controls: 377±33 vs 321±39; diabetic patients: 388±47 vs 336±68 µmol/l; p<0.05).Conclusions/interpretation Despite a lower cerebral phosphocreatine:-ATP ratio in Type 1 diabetic patients at baseline, this ratio does not change in control or diabetic patients during modest hypoglycaemia. However, both groups exhibit subtle changes in intracellular pH and intracellular magnesium concentrations.Abbreviations [Mg²⁺]_i intracellular magnesium - NMR nuclear magnetic resonance - PCr phosphocreatine - pH_i intracellular pH - P_i intracellular inorganic phosphate     

Short communication phosphate supply and arsenate toxicity in ectomycorrhizal fungi

Three species of ectomycorrhizal fungi (Hebeloma crustuliniforme, Suillus variegatus and Cenococcum geophilum) were grown in axenic culture amended with range of AsO4(3-) concentration under three different PO4(3-) regimes. The fungi exhibited different growth responses to AsO4(3-) that varied with PO4(3-) concentration. Suillus variegatus showed the greatest sensitivity to AsO4(3-), with growth almost completely inhibited in the presence of AsO4(3-) under the lower two PO4(3-) treatments. Under the highest PO4(3-) treatment however, growth was enhanced and S. variegatus was able to persist at AsO4(3-) concentrations of up to 4 mM. Hebeloma crustuliniforme also showed high sensitivity to AsO4(3-) especially at low PO4(3-) concentration. The two higher PO4(3-) treatments had an ameliorating effect on AsO4(3-) toxicity in H. crustuliniforme. This demonstrates the ability of PO4(3-) to alleviate AsO4(3-) toxicity. The response from S. variegatus and H. crustuliniforme, both basidiomycetes, was in contrast to the ascomycete C. geophilum. This fungus demonstrated tolerance to AsO4(3-) when grown in culture solution and PO4(3-) did not have an ameliorating effect on AsO4(3-) toxicity in C. geophilum.     

Force transients and minimum cross-bridge models in muscular contraction

Two- and three-state cross-bridge models are considered and examined with respect to their ability to predict three distinct phases of the force transients that occur in response to step change in muscle fiber length. Particular attention is paid to satisfying the Le Chatelier-Brown Principle. This analysis shows that the two-state model can account for phases 1 and 2 of a force transient, but is barely adequate to account for phase 3 (delayed force) unless a stretch results in a sudden increase in the number of cross-bridges in the detached state. The three-state model (A-->B-->C-->A) makes it possible to account for all three phases if we assume that the A-->B transition is fast (corresponding to phase 2), the B-->A transition is of intermediate speed (corresponding to phase 3), and the C-->A transition is slow; in such a scenario, states A and C can support or generate force (high force states) but state B cannot (detached, or low-force state). This model involves at least one ratchet mechanism. In this model, force can be generated by either of two transitions: B-->A or B-->C. To determine which of these is the major force-generating step that consumes ATP and transduces energy, we examine the effects of ATP, ADP, and phosphate (Pi) on force transients. In doing so, we demonstrate that the fast transition (phase 2) is associated with the nucleotide-binding step, and that the intermediate-speed transition (phase 3) is associated with the Pi-release step. To account for all the effects of ligands, it is necessary to expand the three-state model into a six-state model that includes three ligand-bound states. The slowest phase of a force transient (phase 4) cannot be explained by any of the models described unless an additional mechanism is introduced. Here we suggest a role of series compliance to account for this phase, and propose a model that correlates the slowest step of the cross-bridge cycle (transition C-->A) to: phase 4 of step analysis, the rate constant k(tr) of the quick-release and restretch experiment, and the rate constant k(act) for force development time course following Ca(2+) activation.     

Nano in nano: Biosynthesized gold and iron nanoclusters cargo neoplastic exosomes for cancer status biomarking

Timely detection is crucial for successful treatment of cancer. The current study describes a new approach that involves utilization of the tumor cell environment for bioimaging with in-situ biosynthesized nanoscale gold and iron probes and subsequent dissemination of Au-Fe nanoclusters from cargo exosomes within the circulatory system. We have isolated the Au-Fe cargo exosomes from the blood of the treated murine models after in situ biosyntheses from their respective pre-ionic solutions (HAuCl₄, FeCl₂), whereas Na₂SeO₃ supplementation added into Au lethal effect. The microarray data of various differentially expressed genes revealed the up-regulated tumor ablation and metal binding genes in SGC-7901 cell lines after treatment with Au-Fe-Se triplet ionic solution. The isolation of Au-Fe nanoclusters cargo exosomes (nano in nano) after secretion from deeply seated tumors may help in early diagnosis and reveal the tumor ablation status during and after the relevant treatment like radio-chemo therapies et al.