Long-term results of the application of solvent-dehydrated bone xenograft and duramater xenograft for the healing of oroantral osseous defects: a pilot experimental study

Abstract –  The aim of this study was to investigate the long-term effects of the use of human cadaveric solvent-dehydrated bone graft and duramater as a barrier membrane for the treatment of oroantral communication. Standard oroantral osseous defects were created in five minipigs. Subjects received cancellous bone graft in the form of block or microchips, duramater or a combination of bone and membrane. Uneventful healing was achieved in all of the subjects, clinically including the control site which did not receive any material. The operated bone segments were evaluated both by radiological and histological examinations after 6 months. Radiological evaluation was carried out using bone density analysis software and histological evaluation made by light microscopy. Radiological and histological results revealed that bone grafting of oroantral osseous defects improved the bone quality. However, application of duramater did not change this activity, both alone or combined with bone grafts. Within the limits of this experimental study, although solvent-dehydrated bone grafts were found superior and could be applied for the healing of osseous oroantral defects, resorbable membranes did not contribute to this process.     

Persistent polyamorphism in the chiton tooth: From a new biomineral to inks for additive manufacturing

Engineering structures that bridge between elements with disparate mechanical properties are a significant challenge. Organisms reap synergy by creating complex shapes that are intricately graded. For instance, the wear-resistant cusp of the chiton radula tooth works in concert with progressively softer microarchitectural units as the mollusk grazes on and erodes rock. Herein, we focus on the stylus that connects the ultrahard and stiff tooth head to the flexible radula membrane. Using techniques that are especially suited to probe the rich chemistry of iron at high spatial resolution, in particular synchrotron Mössbauer and X-ray absorption spectroscopy, we find that the upper stylus of Cryptochiton stelleri is in fact a mineralized tissue. Remarkably, the inorganic phase is nano disperse santabarbaraite, an amorphous ferric hydroxyphosphate that has not been observed as a biomineral. The presence of two persistent polyamorphic phases, amorphous ferric phosphate and santabarbaraite, in close proximity, is a unique aspect that demonstrates the level of control over phase transformations in C. stelleri dentition. The stylus is a highly graded material in that its mineral content and mechanical properties vary by a factor of 3 to 8 over distances of a few hundred micrometers, seamlessly bridging between the soft radula and the hard tooth head. The use of amorphous phases that are low in iron and high in water content may be key to increasing the specific strength of the stylus. Finally, we show that we can distill these insights into design criteria for inks for additive manufacturing of highly tunable chitosan-based composites.

Biominerals are broadly used by organisms to reinforce structural materials, enabling for instance locomotion, feeding, and defense but also finding application in sensing (1). A defining principle of mineralized tissues is their composite nature, reaping synergy from the combination of a soft macromolecular matrix and a hard, inorganic mineral phase (2, 3). Organisms functionally grade such composites by precisely controlling the phase, size, shape, orientation, dispersion, and spatial distribution of mineral nanoparticles. Harnessing the biological capability to create composites that combine complex shape with mechanical properties that are graded intricately yet over several orders of magnitude in range is of interest for a broad range of functional materials—for instance, for soft robotics (4).Chitons, a class of marine mollusks, are best known for the extreme hardness, rich chemistry, and intricate phase assemblage of their radula teeth (Fig. 1 and SI Appendix, Fig. S1, for recent reviews see refs. 5 and 6; for a cross-cutting review that includes chiton biominerals, see ref. 7). However, the mechanical system of their dentition is not only significantly more complex but also based on a continuous organic phase that is differentially reinforced. The chiton therefore serves as an excellent model system to study biological mechanisms and design principles.Open in a separate windowFig. 1.Radula teeth of C. stelleri. (A) Ventral aspect of C. stelleri [Image credit: Linda Schroeder (photographer)]. (B) Mouth and protruding anterior end of radula (ra) (8). Image credit: VicHigh Marine/David Young. (C) Mosaic image of the entire radula showing all stages of development, including deposition of the organic scaffold (stage I), infiltration of the cusp with ferrihydrite (stage II), conversion to magnetite (stage III), mineralization of the core (stage IV), and mature teeth (stage V). (D) SEM image of the anterior end of the radula with mature teeth. Major lateral teeth consist of the tricuspidate head (hd, 400 × 350 × 150 µm³) and the stylus (st, L-shape 1,400 × 1,400 × 350 µm³). The stylus anchors teeth on the thin (∼100 µm; SI Appendix, Fig. S10C) and flexible radula membrane (rm). The stylus canal (stc) runs along the length of the stylus but terminates below the head. (E) Rendering of a virtual section of a tooth head (hd) and upper stylus (st) generated from a 3D reconstruction of the normalized linear attenuation coefficient (LAC) as determined by synchrotron microcomputed tomography. Note the LAC is highest for the outer magnetite layer (ml) of the head, intermediate for AFP-based composite of the core (co), and rather low in the stylus. Typical for Cryptochiton type teeth, the core is exposed in a window (wi) in the magnetite layer on the trailing (anterior) face of the tooth.The chiton radula is slender ribbon with transverse rows of teeth (Fig. 1 B–D) (9). Two outsize major lateral teeth make contact with the substrate during grazing. Major lateral teeth consist of a tooth head and stylus (Fig. 1 D and E and SI Appendix, Figs. S1 and S10) that is anchored on the radula membrane (10, 11). The stylus canal runs along the length of the hollow stylus and terminates in a dead end below the junction zone between stylus and cusp. During the feeding stroke, the radula slides over a curved supporting surface and bends in two orthogonal directions. This results in a characteristic scraping and sweeping motion of radula teeth (12). The loss of entire rows of teeth due to wear is compensated for by synthesis of new teeth at the posterior end (13, 14). Newly formed teeth mature in several stages as they are transported toward the anterior end by the radula membrane (15). As a result, their entire development can be observed in one animal (Fig. 1C).The function of the radula requires highly disparate material properties. The tooth complex is based on a continuous organic scaffold comprised of semicrystalline, partially deacetylated α-chitin and protein and may be crosslinked by tanning reactions (16). The tooth head is comprised of a highly mineralized cusp with exceptional hardness, wear resistance, and self-sharpening properties (17). The cusp is supported by a softer core. In Cryptochiton-type teeth, magnetite covers the entire posterior surface (leading edge) of the cusp and all but a rectangular window on the anterior surface (trailing edge) (5). The biomineral of the tooth core, amorphous ferric phosphate (AFP), is thus exposed in the window (Fig. 1E and SI Appendix, Fig. S1) (18). Use of at least two biominerals is typical for chiton teeth, and a considerable number has been identified in the core of different species (see ref. 5 and references therein). Additionally, ferrihydrite occurs as a transient precursor phase in stage II of radula development (Fig. 1C) (18).The entire head is mounted on the stylus, an L-shaped chitinous tissue that is integral to the complex movement of the tooth head during the feeding stroke (Fig. 1D and SI Appendix, Fig. S10 A and B) (19). The stylus connects the tooth head to the radula and orients the tooth with respect to the substratum (20). The radula membrane (Fig. 1D and SI Appendix, Fig. S10C) has lower stiffness to accommodate complex shape changes but at the same time must be strong, tough, and resistant to fatigue to survive the cycling bending and unbending during feeding. As a consequence of these vastly different requirements, we expect that mechanical properties are strongly graded. This is well documented for the cusp and core of radula teeth but less explored for the stylus and radula (17, 21, 22).The stylus and the radula membrane are generally referred to as unmineralized tissues, even though the presence of transient mineral has been suggested and the junction zone does mineralize in later stages (5, 22). However, the chemical form in which iron appears in the junction zone and stylus remains unclear. We therefore set out to map the redox state and chemical environment of iron in the tooth of Cryptochiton stelleri with the long-term goal to trace these parameters over the development of the radula and thus gain insight into the mechanisms at play. This would then provide a foothold on the way to designing bio-inspired syntheses.Given the complex shape (Fig. 1 D and E) and small size of chiton teeth and the extraordinarily rich chemistry of iron, mapping of multiple, often poorly crystalline phases requires techniques that combine high spatial resolution with sensitivity for subtle differences in oxidation state and coordination geometry of iron. Synchrotron Mössbauer spectroscopy (SMS) recently emerged as a powerful tool that combines high spatial resolution with the deep chemical insights offered by classical Mössbauer spectroscopy (23–25). Herein, we report on our discovery of a biomineral in the mature upper stylus of C. stelleri using SMS and correlative imaging and spectroscopy techniques.     

汉语失语症患者动词功能损伤的神经语言学分析

目的:分析汉语失语症患者动词功能的损伤和临床病灶部位。方法:于2000-02/04在江苏省徐州市第一、二、三、四医院、解放军第九十七医院等大型医院入住的神经内科患者中选择6位典型的汉语失语症患者作为测查对象。采用北京医科大学汉语失语症成套测验检查法,同时参考波士顿诊断性失语检查法、西方失语症成套测验,并结合头颅CT的检查结果判断失语类型。根据本实验的目的,设计听觉路径和视觉路径两种测试方法。听觉路径通过语音来测试患者的动词功能知识(配价知识);视觉路径则是通过画面来测试患者的动词功能知识。最后,根据被试对测试的正确结果进行统计分析。结果:患者6例均进入结果分析。6例失语症患者的单宾语动词(二价动词)听觉路径成绩为:①字词层级,患者1的正确率为10%,患者2为55%,患者3为75%,患者4为60%,患者5为80%,患者6为35%。②语句层级,患者1的正确率为5%,患者2为40%,患者3为60%,患者4为55%,患者5为65%,患者6为30%。③篇章层级,患者1的正确率为5%,患者2为30%,患者3为50%,患者4为50%,患者5为60%,患者6为25%。6例失语症患者的二价动词视觉路径成绩为:①字词层级,患者1的正确率为15%,患者2为55%,患者3为80%,患者4为65%,患者5为85%,患者6为75%。②语句层级,患者1的正确率为10%,患者2为45%,患者3为65%,患者4为60%,患者5为75%,患者6为65%。③篇章层级,患者1的正确率为5%,患者2为35%,患者3为55%,患者4为50%,患者5为65%,患者6为60%。结论:汉语失语症患者的动词功能中受损伤程度最小的是该动词的基本价位,大脑对任何动词的各种论元结构变换都有极强的适应能力;左额下回后部对动词配价加工起主要作用,还涉及左额下回后部的周围区域和其他较远的相关区域。     

Reliability of procalcitonin as a severity marker in critically ill patients with inflammatory response

Procalcitonin (PCT) is increasingly recognised as an important diagnostic parameter in clinical evaluation of the critically ill. This prospective study was designed to investigate PCT as a diagnostic marker of infection in critically ill patients with sepsis. Eighty-five adult ICU patients were studied. Four groups were defined on the basis of clinical, laboratory and bacteriologic findings as systemic inflammatory response syndrome (SIRS) (n = 10), sepsis (n = 16), severe sepsis (n = 18) and septic shock (n = 41). Data were collected including C-reactive protein (CRP), PCT levels and Sequential Organ Failure Assessment and Acute Physiology and Chronic Health Evaluation II scores on each ICU day. PCT levels were significantly higher in patients with severe sepsis and septic shock (19.25 +/- 43.08 and 37.15 +/- 61.39 ng/ml) than patients with SIRS (0.73 +/- 1.37 ng/ml) (P < 0.05 for each comparison). As compared with SIRS patients, plasma PCT levels were significantly higher in infected patients (21.9 +/- 47.8 ng/ml), regardless of the degree of sepsis (P < 0.001). PCT showed a higher sensitivity (73% versus 35%) and specificity (83% versus 42%) compared to CRP in identifying infection as a cause of the inflammatory response. Best cut-off levels were 1.31 ng/ml for PCT and 13.9 mg/dl for CRP. We suggest that PCT is a more reliable marker than CRP in defining infection as a cause of systemic inflammatory response.     

Compensation for failed sterilization

Two recent Court of Appeal decisions have modified the hitherto settled rules governing the compensation payable following failed and negligently performed sterilization. Compensation is now possible other than for the pain and suffering of the pregnancy where the child or mother is disabled.     

Increased level of polymerase Ⅲ transcribed Alu RNA in hepatocellular carcinoma tissue

There have been extensive observations that RNA containing repetitive elements accumulates in transformed cells and tumor tissues. In the present study, we first obtained result consistent with previous observations by in situ hybridization.     

Motor performance and functional ability in preschool- and early school-aged children with Juvenile Idiopathic Arthritis: a cross-sectional study

Objective  

To describe the level of motor performance and functional skills in young children with JIA.     

Reactivity of individual stereoisomers based on 4-(3-buten-1-ynyl)-1,2,5-trimethyl-4-piperidinol in radical polymerization

The radical polymerization of individual stereoisomers of 4-(3-buten-1-ynyl)-1,2,5-trimethyl-4-piperidinol (1) was investigated. The reaction order with respect to the monomer and the initiator, and also the kinetic and energetic parameters of the polymerization reaction were determined. The values of constants of polymerization of the stereoisomers were found with the help of the “rotating sector” method. It was established that the spatial orientation of the reactive centres with respect to the six-membered heterocycle influences the reactivity of the monomers and leads to a change of the polymerization rate of the stereoisomers by a factor of about 1,5 to 3. To ascertain the influence of the spatial structure on the reactivity of the stereoisomers, quantum chemical calculations for model structures were performed. By means of IR and Raman spectroscopy it was established that the polymerization of 1 occurs via the double bond of the 3-buten-1-ynyl groups.