Articular cartilage and changes in Arthritis: Collagen of articular cartilage

The extracellular framework and two-thirds of the dry mass of adult articular cartilage are polymeric collagen. Type II collagen is the principal molecular component in mammals, but collagens III, VI, IX, X, XI, XII and XIV all contribute to the mature matrix. In developing cartilage, the core fibrillar network is a cross-linked copolymer of collagens II, IX and XI. The functions of collagens IX and XI in this heteropolymer are not yet fully defined but, evidently, they are critically important since mutations in COLIX and COLXI genes result in chondrodysplasia phenotypes that feature precocious osteoarthritis. Collagens XII and XIV are thought also to be bound to fibril surfaces but not covalently attached. Collagen VI polymerizes into its own type of filamentous network that has multiple adhesion domains for cells and other matrix components. Collagen X is normally restricted to the thin layer of calcified cartilage that interfaces articular cartilage with bone.     

Dynamics of pancreatic tissue cells in the rat exposed to long-term caerulein treatment: 1. Biochemical, morphological and morphometrical evaluations

This study was undertaken to evaluate whether hypertrophy and hyperplasia of the pancreatic acinar cells induced by caerulein remained after termination of the hormonal treatment. Rats received subcutaneous injections of saline or caerulein for 4 days and were killed immediately after termination of treatment or 2, 15 and 50 days later. Caerulein treatment induced significant increases in pancreatic weight and contents of DNA, RNA, protein, amylase and chymotrypsinogen along with an increased number of acinar cells per acinus and zymogen granules per acinar cells. During the post-treatment period, the caerulein-treated pancreas reverted to control values for their contents in proteins, enzymes and RNA and number of zymogen granules per acinar cell while the number of pancreatic cells remained constant as indicated by the absence of modification in total DNA content and acinar cells per acinus. During that same period, saline-treated pancreas exhibited constant growth. These morphological and biochemical data indicate that the already present and newly formed acinar cells can remain in place once the trophic stimulus is withdrawn and that they can adjust their cellular components and thus their digestive capacity to the circulating levels of endogenous cholecystokinin released in response to normal meals.     

Behavioural and morphological changes in ciliates induced by the predator Amoeba proteus

The predator Amoeba proteus induced behavioural and morphological changes in ciliates of the genus Euplotes. The frequency of avoidance behaviour in E. octocarinatus increased from 16±5% to 84±5% (SD) after 14 h of coexistence with the predator. The ciliate's width increased from 59±3 μm to 77±4 μm (SDM) within 48 h. Similar behavioural, but not morphological, change was induced in E. daidaleos, but neither morphological nor behavioural responses occurred in E. aediculatus. E. octocarinatus and E. daidaleos populations survived in the presence of A. proteus, whereas E. aediculatus populations became extinct by predation. Induced behavioural response seemed to be the reason for the low predation risk of E. octocarinatus and E. daidaleos. The results suggest that Euplotes ciliates have evolved specific defence mechanisms to various predators. Defensive changes are induced by a chemical substance released from A. proteus. This “kairomone” has a molecular weight between 5000 and 10000 Da. Proteolytic digestion of its activity indicated that the avoidance-inducing substance is a peptide. After the turbellarian Stenostomum sphagnetorum had induced a defensive morphology in E. octocarinatus or E. aediculatus, neither of these ciliates immediately avoided Amoeba proteus. Thus, Euplotes ciliates with a defensive morphology do not have behavioural defences in reaction to all predators.     

Division and death of cells in developing synovial joints and long bones

Articular chondrocytes are a unique set of cells from the time the cellular condensations that become the anlagen of the long bones develop in the embryo. In the presumptive joint the cells of the opposing bones are packed very closely together, but at cavitation, the central, flattened cells move apart to form the articular surfaces. As the articular cartilage develops the cells are pushed further apart by the cartilaginous matrix. To determine the contributions of cell proliferation and death to cavitation and the subsequent development and growth of articular cartilage, direct observations were made to identify mitotic cells and those with apoptotic bodies in haematoxylin-stained sections of developing joints, and growing and ageing articular cartilage of the rabbit knee. These observations were extended using antibodies to the proliferating cell nuclear antigen (PCNA) and TdT-mediated dUTP nick end labelling (TUNEL) on corresponding sections. Low levels of cell division do occur in the articular cartilage up to 6 weeks postnatally, but matrix formation makes the major contribution to the increase in size of the cartilage. Cell death is not observed during cavitation, nor during the development of the articular cartilage proper. Apoptosis is essential, however, for the removal of the epiphyseal cartilage during ossification of the epiphyses and in the growth plate.     

Mesenchymal stem cells in the treatment of articular cartilage degeneration: New biological insights for an old-timer cell

Osteoarthritis (OA) is a debilitating, degenerative joint disease characterized by progressive destruction of articular cartilage. Given the poor repair capacity of articular cartilage and the associated local destructive immune/inflammatory responses involving all joint structures, OA frequently ends up as a “whole joint failure” requiring prosthetic replacement. Current pharmacological efforts, belatedly started, mainly aim at symptomatic pain relief, underscoring the need for novel therapeutic schemes designed to modify the course of the disease. Mesenchymal stem cell (MSC)–based therapy has gained significant interest, sparking the design of multiple trials proving safety while providing promising preliminary efficacy results. MSCs possess ‘medicinal signaling cell’ properties related to their immunomodulatory and anti-inflammatory effects, which induce the establishment of a pro-regenerative microenvironment at the injured tissue. Those trophic effects are paralleled by the long-established chondroprogenitor capacity that can be harnessed to ex vivo fabricate engineered constructs to repair damaged articular cartilage. The present review focuses on these two aspects of the use of MSCs for articular cartilage damage, namely, cell therapy and tissue engineering, providing information on their use criteria, advancements, challenges and strategies to overcome them.     

Organic tissues in rotating bioreactors: fluid-mechanical aspects, dynamic growth models, and morphological evolution

This analysis deals with advances in tissue-engineering models and computational methods as well as with novel results on the relative importance of "controlling forces" in the growth of organic constructs. Specifically, attention is focused on the rotary culture system, because this technique has proven to be the most practical solution for providing a suitable culture environment supporting three-dimensional tissue assemblies. From a numerical point of view, the growing biological specimen gives rise to a moving boundary problem. A "volume-of-fraction" method is specifically and carefully developed according to the complex properties and mechanisms of organic tissue growth and, in particular, taking into account the sensitivity of the construct/liquid interface to the effect of the fluid-dynamic shear stress (it induces changes in tissue metabolism and function that elicit a physiological response from the biological cells). The present study uses available data to introduce a set of growth models. The surface conditions are coupled to the transfer of mass and momentum at the specimen/culture-medium interface and lead to the introduction of a group of differential equations for the nutrient concentration around the sample and for the evolution of tissue mass displacement. The models are then used to show how the proposed surface kinetic laws can predict (through sophisticated numerical simulations) many of the known characteristics of biological tissues grown using rotating-wall perfused vessel bioreactors. This procedure provides a validation of the models and associated numerical method and also gives insight into the mechanisms of the phenomena. The interplay between the increasing size of the tissue and the structure of the convective field is investigated. It is shown that this interaction is essential in determining the time evolution of the tissue shape. The size of the growing specimen plays a critical role with regard to the intensity of convection and the related shear stresses. Convective effects, in turn, are found to impact growth rates, tissue size, and morphology, as well as the mechanisms driving growth. The method exhibits novel capabilities to predict and elucidate experimental observations and to identify cause-and-effect relationships.     

Changes in fused cells induced by hvj (sendai virus): relationship of morphological changes to endocytosis of the surface membrane

Fused Ehlrich ascites tumor (EAT) cells induced by hemagglutinating virus of Japan (HVJ; Sendai virus) had an irregular shape, reflecting the shape of cell aggregates before fusion. During subsequent culture, the fused cells gradually took on a spherical form within 60 min. Examination of the fused cells revealed a vigorous endocytosis of the cell membrane during the morphological change. When EAT cells were treated with porphyrin derivatives, and the morphological change to a spherical form was inhibited, endocytosis of fused cells was also suppressed, suggesting that the change is closely associated with endocytotic activity. Further examination with porphyrin derivatives and hydrogen peroxide suggested that the inhibition of morphological change is due to the suppression of endocytosis by active oxygen species produced by these substances. Experiments using an endocytotic inhibitor, methylamine, indicated that endocytosis is essential for the morphological change that occurs in the fused cells.     

Spontaneous oscillation and mechanically induced calcium waves in chondrocytes

The characteristics of spontaneous calcium (Ca(2+)) oscillation and mechanically induced Ca(2+) waves in articular chondrocytes were studied. In some, but not all, chondrocytes in sliced cartilage and primary cultures, we observed spontaneous oscillation of intracellular Ca(2+) that never spread to adjacent cells. In contrast, a mechanical stimulus to a single cell by touching with a glass rod induced an increase of intracellular Ca(2+) that spread to neighboring cells in a wave-like manner, even though there was no physical contact between the cells. This indicated the release of some paracrine factor from the mechanically stimulated cells. Application of ultrasonic vibration also induced an oscillation of intracellular Ca(2+). The application of a uridine 5'-triphosphate (UTP), UTP, induced a transient increase in intracellular Ca(2+) and the release of adenosine 5'-triphosphate (ATP) in cultured chondrocytes. A P2 receptor antagonist (suramin) and blockers of Cl(-) channels, niflumic acid and 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS), reduced the UTP-induced ATP release. The results indicated that Cl(-) channels were involved in the extracellular release of ATP following mechanical or P2Y receptor stimulation. Thus, ATP stimulation of P2Y receptors elicits an increase in intracellular Ca(2+), triggering further release of ATP from adjacent cells, thereby expanding the Ca(2+) wave in chondrocytes.     

Patterns of angiospermy development before carpel sealing across living angiosperms: diversity,and morphological and systematic aspects

Almost all angiosperms are angiospermous, i.e. the ovules are enclosed in carpels at anthesis and during seed development, but angiospermy develops in different ways across angiosperms. The most common means of carpel closure is by a longitudinal ventral slit in carpels that are partly or completely free. In such carpels, the closure process commonly begins at midlength of the prospective longitudinal slit and then proceeds downward and upward. Closure by a transverse slit is rarer, but it is prominent in groups of the ANITA grade and in a few early branching monocots (some Alismatales) and some early branching eudicots (a few Ranunculaceae and Nelumbonaceae), in these eudicots combined with a more or less developed longitudinal slit. In all these cases the carpels have a single ovule in ventral median position. In ANITA lines with pluriovulate carpels, there is only a short longitudinal slit in the uniformly ascidiate carpels. In carpels with a unifacial style the closure area is narrow; this pattern is rare and scattered mainly in some wind‐pollinated monocots and eudicots. In most angiosperms the carpels become closed before the ovules are visible from the outside of the still incompletely closed carpels (early carpel closure). This is notably the case in the ANITA grade and magnoliids. Delayed carpel closure, with the ovules visible before the carpels are closed, is much rarer and is concentrated in a few monocots (mainly some Alismatales and some Poales) and a few eudicots (mainly a few Ranunculales and many Caryophyllales, and scattered in some other eudicots). A kind of delayed carpel closure (with the placenta visible before closure but mostly not the ovules) also occurs in syncarpous gynoecia with a free central placenta. Most gynoecia with a free central placenta occur in the superasterids. In such gynoecia the individual carpel tips are not differentiated but the opening in young gynoecia has the shape of a circular diaphragm. In this case, when ovary septa and free carpel tips are missing, the number of carpels is sometimes unclear (Primulaceae, Lentibulariaceae, some Santalaceae). Extremely ascidiate carpels are concentrated in the ANITA grade, a few magnoliids and some early branching monocots. Aspects of potential advantages of plicate vs. ascidiate carpels with regard to flexibility of pollen tube transmitting tract differentiation are discussed. © 2015 The Linnean Society of London, Botanical Journal of the Linnean Society, 2015, 178 , 556–591.     

多沙唑嗪光学异构体对高血脂家兔血脂水平的影响

目的:观察左旋多沙唑嗪(-)DOX、右旋多沙唑嗪(+)DOX和消旋多沙唑嗪(±)DOX对高血脂家兔血脂水平及动物死亡率的影响。方法:取普通级雄性新西兰大耳白兔,给予高脂饮食4周后,血清TC小于10mmol/L的8只家兔为普通饮食组,饲以标准饲料。血清TC大于10mmol/L的40只家兔随机分为4组(n=10):高脂模型组、高脂模型+(-)DOX组、高脂模型+(+)DOX组以及高脂模型+(±)DOX组。普通饮食组和高脂模型组家兔腹腔注射无菌双蒸水;其他3组家兔分别腹腔注射(-)DOX、(+)DOX和(±)DOX,连续9周。分析药物对兔血清总胆固醇(TC)、甘油三酯(TG)、高密度脂蛋白胆固醇(HDL-C)和低密度脂蛋白胆固醇(LDL-C)的影响。结果:饲以高脂饮食13周时模型组家兔死亡率达40%,远远高于普通饮食组家兔(10%),亦明显高于(±)DOX和(-)DOX处理组。模型组家兔随高脂饲养的时间延长,血清LDL-C水平进一步显著升高(P0.05和P0.01);而各药物处理组动物的血清LDL-C水平未显著升高(P0.05)。结论:(-)DOX和(±)DOX可提高高脂饮食家兔的生存率,并对高血脂家兔的血清LDL-C紊乱具有轻度的改善作用;该作用可能不是其提高高脂饮食家兔生存率的主要作用机制。     

The leaf base in palms: structural and functional aspects

Abstract

The study of the palm leaf base has consequences that relate to overall development of the crown and the function of the crown as a whole, especially in relation to wind resistance. Palms provide a supreme example of the phenomenon of “giantism”, which is exhibited by many groups of tropical organisms. The distinctive features of the leaf sheath are related to this process, but palms exhibit such a range of adult sizes and occupy such a diversity of habitats that there is considerable scope for comparative study.     

Sclerotia formed by citric acid producing strains of Aspergillus niger: Induction and morphological analysis

Some strains of Aspergillus niger have been previously reported to produce sclerotia under certain conditions. Sclerotia are aggregations of hyphae which can act either as survival or as sexual structures in species related to A. niger. In this study, we were able to induce the formation of sclerotia in the progenitor of the industrial citric acid producing strains of A. niger, ATCC 1015, and in pyrG mutants derived from it. Sclerotia can be stably formed by ATCC 1015 on malt extract agar medium supplemented with raisins, showing a spatial differentiation of the fungus dependent on the addition and on the position of the fruits into the medium. On other media, including malt extract agar, pyrG auxotrophs also form abundant sclerotia, while the complementation of this gene reverses this phenotype. Additionally, a macro- and microscopical analysis of the sclerotia is reported. Our results show that the sclerotia formed by A. niger are similar to those formed by other fungi, not only in their morphology but also in their ability to germinate and regenerate the organism.     

Effects of cadmium exposure on morphological aspects of pancreas,weights of fetus and placenta in streptozotocin-induced diabetic pregnant rats

This study was designed to evaluate the effects of Cd exposure on morphological aspects of β-cell and weights of fetus and placenta in streptozotocin (STZ)-induced diabetic pregnant rats. Ninety-nine virgin female Wistar rats (200–220 g) were mated with 33 males for at least 12 h. From the onset of pregnancy, the rats were divided into four experimental groups (control, Cd treated, STZ treated, and Cd+STZ treated). The Cd-treated group was injected subcutaneously daily with CdCl₂ dissolved in isotonic NaCl, starting at the onset of pregnancy throughout the experiment. Diabetes was induced on the 13th d of pregnancy by a single intraperitoneal injection of STZ in STZ-treated group. In addition to the daily injection of Cd, a single intraperitoneal injection of STZ was also given on the 13th d of pregnancy in the Cd+STZ-treated group. The rats received the last injection 24 h before being sacrificed and 10 randomly selected rats in each group were sacrificed on the 15th and 20th d of pregnancy. Blood samples were taken for the determination of the serum glucose and insulin levels. Maternal pancreases, fetuses, and placentas of sacrificed rats in all groups were harvested (fetal pancreas was also harvested only on the 20th d of pregnancy) for morphological and immunohistochemical examinations. Cd exposure alone caused a degeneration, necrosis, and weak degranulation, but Cd exposure with STZ caused a severe degeneration, necrosis, and degranulation in the β-cells of the pancreatic islets. No morphological or immunohistochemical differences were found in β-cells of fetal pancreatic islets of control or other treatment groups. Cd exposure alone also decreased the fetal and placental weights. The administration of STZ alone, on the other hand, increased the placental weight. Cd, STZ, and Cd+STZ administration increased the glucose and decreased the insulin level. The increase in glucose and decrease in insulin levels were higher when Cd and STZ were given together. All of these changes were more severe on the 20th d than those on the 15th d of the pregnancy. It is concluded that Cd exposure during pregnancy may reduce the birth and placental weights and produce necrosis, degeneration, and degranulation in β-cells of pancreatic islets, causing an increase in the serum glucose level. These changes might be severe in diabetic pregnant mothers.     

JNK pathway in osteoarthritis: pathological and therapeutic aspects

Context: Osteoarthritis (OA) is a common chronic degenerative joint disease resulting in physical disability and reduced quality of life. Different biochemical signaling pathways are involved in the progression of OA, including the c-Jun NH2-terminal kinase (JNK) signal transduction pathway.

Objective: In this study, we have reviewed the recent updates on the association of JNK pathway with OA.

Methods: In this review, we have explored the databases like PubMed, Google Scholar, Medline, Scopus, etc., and collected the most relevant papers of JNK signaling pathway involved in the pathogenesis and therapeutics of OA

Results: JNK has been shown by scientific studies to be activated (phosphorylated) in OA that can play a key role in the cartilage destruction. Activation of JNK causes the phosphorylation of c-Jun that causes decreased proteoglycan synthesis and enhanced production of matrix metalloproteinase 13 (MMP-13). Overproduction of MMP-13 by chondrocytes plays a central role in cartilage degeneration in OA. Thus, targeting JNK pathway might be a promising therapeutic application for the prevention and treatment of OA. A number of JNK-inhibitors have been used in vitro and in vivo studies; however, not yet been translated into human use.

Conclusions: This review study indicates that JNK pathway plays an important role in development and progression of OA, and targeting the JNK pathway might be a potential approach for the treatment of OA in future.     

Determination of zinc contents in rabbits with cerebral ischemia by NAA and ICP-AES

Cerebral ischemia is an important cerebral vascular disease, and zinc is a necessary trace element for humans. In this work, a cerebral ischemia model of rabbit was established by operation. The samples of brain and serum in the animal models were collected. The Zn contents in the samples were determined by neutron activation analysis and inductively coupled plasma-atomic emission spectrometry. The results show the Zn contents in brain decreased 2 mo after cerebral ischemia, and Zn contents in serum decreased even more obviously. In addition, a positive correlation of Zn contents between left and right cerebral hemispheres was observed, and the positive correlation between brain and serum was also observed. A test of Chinese medicine was also carried out in the work. Two Chinese medicines were fed to rabbits with cerebral ischemia in the experiments. The results showed they probably can prevent the decrease of Zn contents in serum.     

Collagen in tissue-engineered cartilage: Types,structure, and crosslinks

The function of articular cartilage as a weight-bearing tissue depends on the specific arrangement of collagen types II and IX into a three-dimensional organized collagen network that can balance the swelling pressure of the proteoglycan/ water gel. To determine whether cartilage engineered in vitro contains a functional collagen network, chondrocyte-polymer constructs were cultured for up to 6 weeks and analyzed with respect to the composition and ultrastructure of collagen by using biochemical and immunochemical methods and scanning electron microscopy. Total collagen content and the concentration of pyridinium crosslinks were significantly (57% and 70%, respectively) lower in tissue-engineered cartilage that in bovine calf articular cartilage. However, the fractions of collagen types II, IX, and X and the collagen network organization, density, and fibril diameter in engineered cartilage were not significantly different from those in natural articular cartilage. The implications of these findings for the field of tissue engineering are that differentiated chondrocytes are capable of forming a complex structure of collagen matrix in vitro, producing a tissue similar to natural articular cartilage on an ultrastructural scale. J. Cell. Biochem. 71:313–327, 1998. © 1998 Wiley-Liss, Inc.     

Stereoselective determination of benalaxyl in plasma by chiral high-performance liquid chromatography with diode array detector and application to pharmacokinetic study in rabbits

A chiral high-performance liquid chromatography method with diode array detector was developed and validated for stereoselective determination of benalaxyl (BX) in rabbit plasma. Good separation was achieved at 20 degrees C using cellulose tris-(3,5-dimethylphenylcarbamate) as chiral stationary phase, a mixture of n-hexane and 2-propanol (97:3) as mobile phase at a flow rate of 1.0 ml/min. The assay method was linear over a range of concentrations (0.25-25 microg/ml) in plasma and the mean recovery was greater than 90% for both enantiomers. The limits of quantification and detection for both enantiomers in plasma were 0.25 and 0.1 microg/ml, respectively. Intra- and interday relative standard deviations (RSDs) did not exceed 10% for three-tested concentrations. The method was successfully applied to pharmacokinetic studies of BX enantiomers in rabbits. The result suggested that the pharmacokinetics of BX enantiomers was stereoselective in rabbits.     

Histological and histochemical alterations in the liver induced by lead chronic toxicity

Adult males of the Wistar albino rats (Rattus norvegicus) were exposed to lead acetate trihydrate in drinking water (0.0%, 0.25%, 0.5%, 1% and 2% for 1–12 months) to investigate histological and histochemical alterations induced by lead intoxication in the liver. Chronic exposure to subtoxic concentrations of lead produced changes in the hepatocytes, portal triads and the sinusoids. The alterations in the hepatocytes were mainly anisokaryosis, nuclear vesiculation, binucleation, cytoplasmic inclusions, cytoplasmic swelling, hydropic degeneration, necrosis and reduction in glycogen content. In addition, portal triads mild chronic inflammation, Kupffer cells hyperplasia and occasional fatty change were seen together with hemosiderosis. No portal fibrosis or cirrhosis was detected due to chronic subtoxic doses of lead exposure in the liver of any member of the dose groups over the entire period of the study. Chronic lead exposure also increased the activities of alkaline phosphatase and α-glycerophosphate-dehydrogenase which might be an adaptation to the metabolic, structural and functional changes in the organelles of hepatic cells due to lead intoxication. The findings revealed that chronic exposure to lead produced significant histological and histochemical changes in the liver of the Wistar albino rats.     

Resistance to RHD virus in wild Australian rabbits: Comparison of susceptible and resistant individuals using a genomewide approach

Deciphering the genes involved in disease resistance is essential if we are to understand host–pathogen coevolutionary processes. The rabbit haemorrhagic disease virus (RHDV) was imported into Australia in 1995 as a biocontrol agent to manage one of the most successful and devastating invasive species, the European rabbit (Oryctolagus cuniculus). During the first outbreaks of the disease, RHDV caused mortality rates of up to 97%. Recently, however, increased genetic resistance to RHDV has been reported. Here, we have aimed to identify genomic differences between rabbits that survived a natural infection with RHDV and those that died in the field using a genomewide next‐generation sequencing (NGS) approach. We detected 72 SNPs corresponding to 133 genes associated with survival of a RHD infection. Most of the identified genes have known functions in virus infections and replication, immune responses or apoptosis, or have previously been found to be regulated during RHD. Some of the genes identified in experimental studies, however, did not seem to play a role under natural selection regimes, highlighting the importance of field studies to complement the genomic background of wildlife diseases. Our study provides a set of candidate markers as a tool for the future scanning of wild rabbits for their resistance to RHDV. This is important both for wild rabbit populations in southern Europe where RHD is regarded as a serious problem decimating the prey of endangered predator species and for assessing the success of currently planned RHDV variant biocontrol releases in Australia.