人类骨组织特征研究

为解决杀人毁尸案中骨骼残片的法医鉴定问题,对人类不同部位的骨骼进行组织学研究,为比较骨骼残片是否为人类骨骼提供科学基础。本研究提取的人类骨骼有颅骨、四肢长骨。将提取的骨片制成骨组织片,在显微镜下观察,并将观察结果输入计算机进行分析。通过对人类不同部位骨骼的组织学特征研究,描述了人类骨组织的板层结构、骨单位及骨小管的形态。本研究结果在法医学、人类学及考古学等领域有一定的应用价值。     

白念珠菌生物被膜的研究进展

白念珠菌是一种机会性致病真菌,也是引起真菌血症和播散性念珠菌病的主要病原体[1]。白念珠菌定植于人体的皮肤和黏膜等部位,当机体的正常防御功能受损时,如创伤、营养失调、免疫功能缺陷、激素和抗生素的应用导致菌群失调等[2],白念珠菌会过度生长,从口腔、咽喉和生殖道等浅表黏膜感染转变为循环系统、骨骼和大脑的全身性侵袭性念珠菌病[3]。白念珠菌常以生物被膜的形式生长在植入体内的生物材料上,比如中心静脉导管、导尿管、心脏起搏器和其他与器官直接接触的材料。     

鱼的人工呼吸方法

在开展诸如“观察鱼的外形与游泳”、“观察鱼的呼吸与鳃的外形”、“观察鱼尾鳍血液流动情况”等生物科学探究活动中，常常会因为鱼停止呼吸或呼吸十分缓慢而影响探究效果。在日常生活中，一条鲜活的鱼在水中保存不久也会因呼吸衰弱甚至窒息而不能继续保存。那么，怎样才能延长鱼的存活时间呢？能不能对鱼进行人工呼吸呢？如何对鱼进行人工呼吸？[第一段]     

粪便样本不同保存方式对肠道菌群测序结果的影响

[目的]本文探究了3种室温保存剂和-80℃C冷冻保存对粪便样本中菌群结构的影响,为大规模、标准化的采样提供参考.[方法]本研究采集了5名健康志愿者的新鲜粪便作为测试样本,采用4种不同的保存方式保存:DETs室温保存、GITC室温保存、RNAlater室温保存和-80℃冷冻保存,在保存0、1、3、7、14、28 d后,采...     

贵州马鞍山遗址发现旧石器时代骨角制品

正最近一期的国际学术期刊《考古科学》(Journal of Archaeological Science)发表了中国科学院古脊椎动物与古人类研究所高星研究员所带领的的研究团队与法国波尔多大学Francesco d'Errico教授以及南非金山大学Lucinda R.Backwell等学者对贵州马鞍山遗址中17件骨角器的研究成果。骨角器是旧石器时代考古遗存中较为常见的一种工具类型。早期的骨角制品大多是古人类经简单打击修理或直接使用破裂的动物骨骼或鹿角等有机质材料的结果;而相对晚近期的同类产品则是古人类适应于骨、角等有机质材料的特定属性,通过刮削、磨制、抛光等技术手     

化石保存的方式

地层中的化石按其保存特点,可分为实体化石、模铸化石、遗迹化石和化学化石4大类。1实体化石指由生物遗体的全部或一部分保存而成的化石,其中大多数保存了生物的硬体部分,如外壳、骨骼等。实体化石又可分为未变实体化石、微变硬体化石和石化化石3种。1．1未变实体化石特指古代生物软体部分尚保存的化石。著名的西伯利亚和阿拉斯加第四纪冻土中发现的猛码象,其毛、皮、内脏等都保存完好,甚至有些个体的肉在发现后,还可被食肉兽吃掉。从它们胃中的残留食物及抱子花粉,可以推知它们的食性。其次,如保存在第四纪搪玻中的昆虫化石,其中…     

保存动物组织内RNA的方法改进

以大鼠为试验材料,用Trizol法提取动物组织内的RNA,通过比较得到,存放于250mmol/L柠檬酸钠,40mmol/L乙二胺四乙酸(EDTA),4.5mol/L硫酸铵,200mmol/L异硫氰酸胍的pH5.5保存溶液中的动物组织中的RNA与常规保存方法保存的动物组织提取的RNA质量的相比,在上述保存液中保存的动物组织可以得到质量高、完整性好的总RNA,RT-PCR分析显示提取的总RNA反转录的cDNA完整、活性高,这种方法具有快速、简单、方便的特点。     

骨骼标本的修复方法

骨胳标本如果原来工艺质量不高或使用时保存不妥 ,时间长了会发生“反油”、变黄、发霉、穿连铅丝断裂和骨块散落等情况 ,应及时修复。方法如下 :1)标本“反油”、发霉是原先骨胳标本脱脂不够所致。补救办法是 :取 1份氨水加 3份水配制成脱脂液 ,将标本浸泡 36～ 4 8h。比较粗大的骨胳 ,脱脂液可配得浓些、浸泡时间也可长些。相反如鱼、蛇、蛙等动物的小型骨胳可浓度小些、浸泡时间短些。脱脂后用水冲洗干净、晾干。2 )标本发黄 ,可重新漂白。将标本放入体积分数为2 5 %的双氧水中浸泡 4 8h左右即可。当骨胳呈乳白色、各个部位颜色很均匀 ,…     

鲜叶保存方法对茶树基因组DNA提取效果的影响

探讨一种简便有效的鲜叶保存方法,对克服茶树DNA研究中远距离采样的困难具有重要意义．为此,以槠叶齐品种的鲜梢为材料,分别采用-20℃、-70℃、硅胶脱水干燥3种方法保存样品,采用改进的CTAB法与SDS法分别对3种方法保存的样品及对照样(鲜叶)进行基因组DNA的提取与纯化,对所得DNA的质量进行多重检测的结果表明,硅胶脱水干燥法保存的样品与其他几种方法保存的样品一样,都提取获得了高质量的DNA,因此,硅胶脱水干燥法可作为远距离采样制备茶树DNA的一种较好的鲜叶保存方法,具有操作简单、经济实用、不受时空等条件限制的特点,该方法同样适用于其他植物．     

荒漠麻蜥骨骼系统的解剖及与相近科属蜥蜴骨骼特征比较

采用透明骨骼染色法,观测了荒漠麻蜥Eremias przewaskii比较完整的骨骼系统,对其各部分骨骼组成、形态和位置作了详细的描述,为麻蜥属的分类及演化提供骨骼方面的基础资料。其骨骼可分为中轴骨骼(包括头骨、脊柱、胸骨和肋骨)和附肢骨骼(包括肩带、腰带、前肢骨和后肢骨)。其头骨呈三角形,眼窝与颞窝相通,不完整。颈椎8枚,胸椎5枚,腰椎13枚,荐椎2枚,尾椎44～45枚。与已报道的蜥蜴物种骨骼特征相比较,发现其前肢腕骨部位、尺骨和桡骨远端中间具1枚骨化不完全的籽骨——介间骨;在前肢腕骨与掌骨的腹面,有2块平面不规整四方形的掌籽骨,位于连接腕骨与各掌骨的韧带中间;在后肢股骨远端的关节内侧与髌骨相对的位置存在1粒籽骨,为股腓侧豆状骨;跗骨腹面下方有1枚三角形籽骨——跗籽骨。     

Age and sex bias in the reconstruction of past population structures

Palaeodemographical studies are founded on the assumption that the sex and age distribution of the skeletal sample reflects the constitution of the original population. It is becoming increasingly clear, however, that the type and amount of information that may be derived from osteoarchaeological collections are related to the state of preservation of remains. This work proposes a new method to evaluate bone preservation, to identify age and sex biases in the preservation of human skeletal remains, and to assess whether differences in preservation patterns are more dependent on factors intrinsic or extrinsic to anatomical features of human bones. Three osteological collections and over 600 skeletons were observed. The state of preservation of human bones was assessed using three preservation indexes: the anatomical preservation index (API), the bone representation index (BRI), and the qualitative bone index (QBI). The results suggest that subadult skeletons are generally more poorly preserved and with bones less well-represented than adult skeletons. Among subadults, female and male skeletons have different patterns of preservation according to their age. This pattern of preservation depends on intrinsic anatomical properties of bones themselves, while external factors can only increase these differences in the state of preservation and representation of osseous remains. It is concluded from this that failure to recognize these differences may lead to misleading interpretations of paleodemography of past human populations.     

Problems in determination of skeletal lead burden in archaeological samples: an example from the First African Baptist Church population

Human bone lead content has been demonstrated to be related to socioeconomic status, occupation and other social and environmental correlates. Skeletal tissue samples from 135 individuals from an early nineteenth century Philadelphia cemetery (First African Baptist Church) were studied by electrothermal atomic absorption spectrometry and X-ray fluorescence for lead content. High bone lead levels led to investigation of possible diagenetic effects. These were investigated by several different approaches including distribution of lead within bone by X-ray fluorescence, histological preservation, soil lead concentration and acidity as well as location and depth of burial. Bone lead levels were very high in children, exceeding those of the adult population that were buried in the cemetery, and also those of present day adults. The antemortem age-related increase in bone lead, reported in other studies, was not evidenced in this population. Lead was evenly deposited in areas of taphonomic bone destruction. Synchrotron X-ray fluorescence studies revealed no consistent pattern of lead microdistribution within the bone. Our conclusions are that postmortem diagenesis of lead ion has penetrated these archaeological bones to a degree that makes their original bone lead content irretrievable by any known method. Increased bone porosity is most likely responsible for the very high levels of lead found in bones of newborns and children.     

Optimum stiffness for leg bones

A limb bone will be lighter if it is made thinner. However, thinner bones are more flexible (for given length and shape of cross-section) so their muscles must shorten more to move the distal end of the bone against a resisting force. To shorten more, a muscle needs longer muscle fibres and so must be heavier. Thus a particular thickness for the bone will enable the combined mass of bone plus muscle to be minimized. Peak stresses due to bending moments, in bones that were optimized according to this criterion, would be about ±70 MPa. Stresses of about this magnitude have been found in leg bones of various mammals, in strenuous activities such as running and jumping. However, similar stresses might be predicted on grounds of strength requirements, to give adequate factors of safety.     

Mammalian collagenase predisposes bone surfaces to osteoclastic resorption

Summary The cell-free endocranial surface of young adult rat parietal bones was used as a substrate for bone cell-derived mammalian collagenase. Incubation of parietal bones in a concentration of enzyme comparable to that secreted by osteoblastic cells in vitro caused destruction of surface osteoid, and resulted in exposure of mineral onto the bone surface. Bones so pre-treated were considerably more susceptible to osteoclastic resorption than bones preincubated in the absence of collagenase. These results are consistent with the view that the osteoid layer which covers bone surfaces acts as a barrier to osteoclastic contact with underlying, resorption — stimulating bone mineral; and that cells of the osteoblastic lineage induce osteoclastic resorption through collagenase secretion which, by digestion of the surface osteoid, exposes bone mineral to osteoclastic contact.     

Sediment cytology in bone biopsies

The cytologic examination of smears prepared from the sediment of biopsy specimen fixatives ("sediment cytology") was used to study 70 bone lesions biopsied with a suspicion of malignancy. The smears were adequately cellular in most cases and showed good morphologic preservation; some contained fragments of tissue. Cytology was able to identify the smears from the 47 malignant lesions as malignant, but was not always able to identify the histologic type. While the osteoclastomas, Ewing's sarcomas and metastatic carcinomas were accurately diagnosed, the osteogenic sarcomas could only be identified as sarcomas and the scanty smears from chondrosarcomas only permitted a diagnosis of malignancy. The latter was also true for soft tissue lesions and lymphoma involving the bones. The 12 benign lesions yielded less cellular specimens and were more difficult to cytologically diagnose. The 11 inflammatory lesions were identified as nonmalignant. While this simple technique of sediment cytology can provide an early diagnosis for bone lesions, the final diagnosis requires the histopathologic study of the actual biopsy specimen.     

X-ray microanalysis of fossil dinosaur bone: age differences in lead, iron, and magnesium content.

Bones of dinosaurs, Gallimimus bullatus, belonging to selected age groups, were studied using an X-ray microanalyser. The content of lead, iron, and magnesium, as well as the distribution of those elements in the investigated bone areas were determined. The results showed, that bones of old animals contained the highest level of lead and iron, whereas in young dinosaurs the respective values were lowest. The obtained data were compared with the results of X-ray microanalysis of the contemporary bone.     

Femoral strength is better predicted by finite element models than QCT and DXA.

Clinicians and patients would benefit if accurate methods of predicting and monitoring bone strength in-vivo were available. A group of 51 human femurs (age range 21-93; 23 females, 28 males) were evaluated for bone density and geometry using quantitative computed tomography (QCT) and dual energy X-ray absorptiometry (DXA). Regional bone density and dimensions obtained from QCT and DXA were used to develop statistical models to predict femoral strength ex vivo. The QCT data also formed the basis of a three-dimensional finite element (FE) models to predict structural stiffness. The femurs were separated into two groups; a model training set (n = 25) was used to develop statistical models to predict ultimate load, and a test set (n = 26) was used to validate these models. The main goal of this study was to test the ability of DXA, QCT and FE techniques to predict fracture load non-invasively, in a simple load configuration which produces predominantly femoral neck fractures. The load configuration simulated the single stance phase portion of normal gait; in 87% of the specimens, clinical appearing sub-capital fractures were produced. The training/test study design provided a tool to validate that the predictive models were reliable when used on specimens with "unknown" strength characteristics. The FE method explained at least 20% more of the variance in strength than the DXA models. Planned refinements of the FE technique are expected to further improve these results. Three-dimensional FE models are a promising method for predicting fracture load, and may be useful in monitoring strength changes in vivo.     

几种真姬菇菌种保藏方法的保藏效果对比

【背景】菌种保藏方法与保藏效果是菌种质量的前提和保证。随着真姬菇Hypsizygus marmoreus栽培规模和产量的逐年递增,选择最佳的菌种保藏方法也越来越迫切。【目的】对真姬菇菌种的常见保藏方法及保藏效果进行分析和研究,寻找简便、高效、廉价的真姬菇菌种保藏方法。【方法】通过对比菌丝生长率、菌丝脱氢酶活性以及菌丝对色度培养基的脱色率等指标参数来评价保藏方法的保藏效果。【结果】通过对三大类27种真姬菇菌种保藏方法 3个月保藏效果的对比分析发现,三大类菌种保藏方法中保藏效果最好的是水溶液保藏法,其中以0.1%PEG6000水溶液保藏效果最佳;其次为木屑保藏法,其中以盐水浸泡过的杨木木屑保藏效果最好;斜面保藏法效果最差。正常保藏实验的效果好于加速保藏实验。【结论】与当前真姬菇菌种保藏的常规方法相对比,本实验所采用的菌种保藏方法大大拓宽了菌种保藏方法的种类与范围,提高了菌种保藏的效果。     

Modeling and remodeling responses to normal loading in the human lower limb

Limb bones are designed to be strong enough to support the body and yet be energetically conservative during locomotion. Bones of the distal segment, which are relatively costly to move, are often more slender than bones of the proximal segments, even though they must sustain proportionally greater loads. As a result, they are expected to experience a higher incidence of microdamage. With this constraint in mind, Lieberman and Crompton (1998 Principles of Animal Design, Cambridge: Cambridge University Press, p. 78-86) proposed that bones response to strain varies along the proximo-distal axis of the limb. In order to avoid fatigue fractures due to the accumulation of microdamage, the distal segment, in comparison to the proximal segment, will have an increase in remodeling events to replace damaged bone. In this paper, we test the hypothesis of Lieberman and Crompton (1998) with respect to the human lower limb. With a sample of adult individuals, we compare tibiae and femora for mid-diaphyseal cross-sectional geometry and Haversian remodeling differences. Our results indicate that the human limb is not designed like that of quadrupedal cursorial animals. The tibia is not less resistant in bending and torsion, and does not remodel more than the femur. Our findings fail to support the hypothesis of Lieberman and Crompton (1998) and suggest, instead, that the human lower limb is not designed like a cursorial animal limb. In addition, our results support previous observations that remodeling is not uniform within the cross section of a bone, probably a reflection of different loading histories within the different regions of the cross section.     

A comparison of primate, carnivoran and rodent limb bone cross-sectional properties: are primates really unique?

The cross-sectional properties of mammalian limb bones provide an important source of information about their loading history and locomotor adaptations. It has been suggested, for instance, that the cross-sectional strength of primate limb bones differs from that of other mammals as a consequence of living in a complex arboreal environment (Kimura, 1991, 1995). In order to test this hypothesis more rigorously, we have investigated cross-sectional properties in samples of humeri and femora of 71 primate species, 30 carnivorans and 59 rodents. Primates differ from carnivorans and rodents in having limb bones with greater cross-sectional strength than mammals of similar mass. This might imply that primates have stronger bones than carnivorans and rodents. However, primates also have longer proximal limb bones than other mammals. When cross-sectional dimensions are regressed against bone length, primates appear to have more gracile bones than other mammals. These two seemingly contradictory findings can be reconciled by recognizing that most limb bones experience bending as a predominant loading regime. After regressing cross-sectional strength against the product of body mass and bone length, a product which should be proportional to the bending moments applied to the limb, primates are found to overlap considerably with carnivorans and rodents. Consequently, primate humeri and femora are similar to those of nonprimates in their resistance to bending. Comparisons between arboreal and terrestrial species within the orders show that the bones of arboreal carnivorans have greater cross-sectional properties than those of terrestrial carnivorans, thus supporting Kimura's general notion. However, no differences were found between arboreal and terrestrial rodents. Among primates, the only significant difference was in humeral bending rigidity, which is higher in the terrestrial species. In summary, arboreal and terrestrial species do not show consistent differences in long bone reinforcement, and Kimura's conclusions must be modified to take into account the interaction of bone length and cross-sectional geometry.