Changes of extracellular space volume of the cerebral cortex during peripheral stimulation in rats

Changes of extracellular space (ECS) volume evoked by peripheral repetitive stimulation were studied in the cerebral cortex. Extracellular volume and its changes were measured by electrical impedance method with the fourth electrode scheme. Measurements indicate that the dynamic changes of ECS volume accompany electrical activity of cortex and have value 3-5%.     

The evolutionary history of Drosophila buzzatii. XXIII. High content of nonsatellite repetitive DNA in D. buzzatii and in its sibling D. koepferae.

The frequency and types of repetitive nonsatellite DNA of two sibling species of the repleta group of Drosophila, D. buzzatii, and D. koepferae have been determined. For each species, the analysis is based on a sample of more than 100 clones (400 kb) obtained from genomic DNA. A theoretical model has been developed to correct for the presence of a mixture of repetitive and unique DNA in these clones. After correction, a high content of repetitive DNA has been demonstrated for both species (D. buzzatii, 19-26%; D. koepferae, 27-32%). The repetitive sequences have been classified according to their hybridization pattern when used as probes against genomic DNA and by their in situ hybridization signals on polytene chromosomes. Data suggest that the main nonsatellite component of these species is simpler and more repetitive than that of D. melanogaster, pointing to a wide variability in content and class size distribution of repetitive DNA among Drosophila species.     

Initiation and progression of mechanical damage in the intervertebral disc under cyclic loading using continuum damage mechanics methodology: A finite element study

It is difficult to study the breakdown of disc tissue over several years of exposure to bending and lifting by experimental methods. There is also no finite element model that elucidates the failure mechanism due to repetitive loading of the lumbar motion segment. The aim of this study was to refine an already validated poro-elastic finite element model of lumbar motion segment to investigate the initiation and progression of mechanical damage in the disc under simple and complex cyclic loading conditions. Continuum damage mechanics methodology was incorporated into the finite element model to track the damage accumulation in the annulus in response to the repetitive loading. The analyses showed that the damage initiated at the posterior inner annulus adjacent to the endplates and propagated outwards towards its periphery under all loading conditions simulated. The damage accumulated preferentially in the posterior region of the annulus. The analyses also showed that the disc failure is unlikely to happen with repetitive bending in the absence of compressive load. Compressive cyclic loading with low peak load magnitude also did not create the failure of the disc. The finite element model results were consistent with the experimental and clinical observations in terms of the region of failure, magnitude of applied loads and the number of load cycles survived.     

腰椎间盘突出症的CT及MRI诊断

目的：总结分析１９１例腰椎间盘突出症的ＣＴ及ＭＲＩ影像特征。方法：ＣＴ组１０４例,ＭＲＩ组８７例,同时行ＣＴ及ＭＲ检查４４例。结果：ＣＴ组中,椎间盘同位于Ｌ３－４者１２例,Ｌ４－５者３２例,Ｌ５－Ｓ１者６０例。骨质增生３１例,髓核钙化１１例,后纵韧带钙化９例。ＭＲ组中,椎间盘突出位于Ｌ３－４者１３例,Ｌ４－５者３９例,Ｌ５－Ｓ１者３５例,椎间盘突变性４１例。     

Imbalanced Protein Expression Patterns of Anabolic,Catabolic, Anti-Catabolic and Inflammatory Cytokines in Degenerative Cervical Disc Cells: New Indications for Gene Therapeutic Treatments of Cervical Disc Diseases

Degenerative disc disease (DDD) of the cervical spine is common after middle age and can cause loss of disc height with painful nerve impingement, bone and joint inflammation. Despite the clinical importance of these problems, in current publications the pathology of cervical disc degeneration has been studied merely from a morphologic view point using magnetic resonance imaging (MRI), without addressing the issue of biological treatment approaches. So far a wide range of endogenously expressed bioactive factors in degenerative cervical disc cells has not yet been investigated, despite its importance for gene therapeutic approaches. Although degenerative lumbar disc cells have been targeted by different biological treatment approaches, the quantities of disc cells and the concentrations of gene therapeutic factors used in animal models differ extremely. These indicate lack of experimentally acquired data regarding disc cell proliferation and levels of target proteins. Therefore, we analysed proliferation and endogenous expression levels of anabolic, catabolic, ant-catabolic, inflammatory cytokines and matrix proteins of degenerative cervical disc cells in three-dimensional cultures. Preoperative MRI grading of cervical discs was used, then grade III and IV nucleus pulposus (NP) tissues were isolated from 15 patients, operated due to cervical disc herniation. NP cells were cultured for four weeks with low-glucose in collagen I scaffold. Their proliferation rates were analysed using 3-(4, 5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide. Their protein expression levels of 28 therapeutic targets were analysed using enzyme-linked immunosorbent assay. During progressive grades of degeneration NP cell proliferation rates were similar. Significantly decreased aggrecan and collagen II expressions (P<0.0001) were accompanied by accumulations of selective catabolic and inflammatory cytokines (disintegrin and metalloproteinase with thrombospondin motifs 4 and 5, matrix metalloproteinase 3, interleukin-1β, interleukin-1 receptor) combined with low expression of anti-catabolic factor (metalloproteinase inhibitor 3) (P<0.0001). This study might contribute to inhibit inflammatory catabolism of cervical discs.     

The use of multiple typing methods allows a more accurate molecular characterization of Vibrio parahaemolyticus strains isolated from the Italian Adriatic Sea

Vibrio parahaemolyticus is a natural inhabitant of marine environments and constitutes part of the autochthonous microbial communities, but is also associated with human gastroenteritis, wound infections and septicemia. Recently, a number of clinical cases of infection due to ingestion of seafood contaminated with V. parahaemolyticus and potentially pandemic marine strains isolated from water and plankton have been reported in Europe. To identify the source of virulent strains and to analyze the possible persistence, in time and space, of particular clones, the molecular typing of Vibrio strains is of high epidemiological interest. In this study, we applied pulsed-field gel electrophoresis and two PCR-based techniques (enterobacterial repetitive intergenic consensus- and repetitive extragenic palindromic-PCR) to establish the DNA fingerprints for the analysis of genetic variability among the environmental V. parahaemolyticus strains isolated in the area of the Venetian Lagoon. A temporal distribution of the environmental strains in the studied geographical area and, in some cases, a strong association between a certain genetic profile and a specific source have been evidenced. A number of genetic clusters/clones seem to persist over time, reappearing in the marine environment for subsequent months and also at a 1-year gap. The use of multiple typing methods allowed a more accurate characterization of the environmental strain genetic profiles and the identification of clones hardly revealed through common techniques.     

Ultrastructure of Lamblia duodenalis. I. Body Surface, Sucking Disc and Median Bodies

SYNOPSIS. The body surface, sucking disc and median bodies of Lamblia duodenalis have been studied on ultrathin sections in the electron microscope. The body is covered by a pellicle, displaying a striated structure in the area of the sucking disc. The striation is due to 150 Å thick dense ridges which are spaced in distances of 200–400 Å. The ridges are formed by the internal pellicular membrane and have a triangular cross section with a very dense apex. They are arranged concentrically and run parallel to the surface of the sucking disc lobes. Anteriad to the nuclei in the median line a space is free of ridges. The margin of the sucker is elevated above the body forming a sharp crest of the ridged pellicle.
This crest is the inner wall of a marginal groove delimiting the sucker from the body. The outer margin is circumscribed by a fold in the body tapering to the posterior end. A ventral groove containing the two ventral flagella lies in the median line. The movement of the ventral flagella pushes the medium through the marginal and ventral grooves thus producing vacuum in the sucker area.
The median bodies are composed of numerous 150 Å thick tubular fibrils. They differ in their ultrastructure from the parabasal apparatus in other flagellates and have nothing in common with the kinetoplasts. Their functional significance awaits elucidation.     

Diversity and evolution of four dispersed repetitive DNA sequences in the genus Secale

We present the first characterization of 360 sequences in six species of the genus Secale of both cultivated and wild accessions. These include four distinct kinds of dispersed repetitive DNA sequences named pSc20H, pSc119.1, pSaO5(411), and pSaD15(940) belonging to the Revolver family. During the evolution of the genus Secale from wild to cultivated accessions, the pSaO5(411)-like sequences became shorter mainly because of the deletion of a trinucleotide tandem repeating unit, the pSc20H-like sequences displayed apparent homogenization in cultivated rye, and the second intron of Revolver became longer. In addition, the pSc20H-, pSc119.1-, and pSaO5(411)-like sequences cloned from wild rye and cultivated rye could be divided into two large clades. No single case of the four kinds of repetitive elements has been inherited by each Secale accession from a lone ancestor. It is reasonable to consider the vertical transmission of the four repetitive elements during the evolution of the genus Secale. The pSc20H- and pSaO5(411)-like sequences showed evolutionary elimination at specific chromosomal locations from wild species to cultivated species. These cases imply that different repetitive DNA sequences have played different roles in the chromosome development and genomic evolution of rye. The present study adds important information to the investigations dealing with characterization of dispersed repetitive elements in wild and cultivated rye.     

Inclusion of regional poroelastic material properties better predicts biomechanical behavior of lumbar discs subjected to dynamic loading

Understanding the relationship between repetitive lifting and the breakdown of disc tissue over several years of exposure is difficult to study in vivo and in vitro. The aim of this investigation was to develop a three-dimensional poroelastic finite element model of a lumbar motion segment that reflects the biological properties and behaviors of in vivo disc tissues including swelling pressure due to the proteoglycans and strain-dependent permeability and porosity. It was hypothesized that when modeling the annulus, prescribing tissue specific material properties will not be adequate for studying the in vivo loading and unloading behavior of the disc. Rather, regional variations of these properties, which are known to exist within the annulus, must also be included. Finite element predictions were compared to in vivo measurements published by Tyrrell et al. (1985) of percent change in total stature for two loading protocols, short-term creep loading and standing recovery and short-term cyclic loading with standing recovery. The model in which the regional variations of material properties in the annulus had been included provided an overall better prediction of the in vivo behavior as compared to the model in which the annulus properties were assumed to be homogenous. This model will now be used to study the relationship between repetitive lifting and disc degeneration.     

In vivo age- and sex-related creep of human lumbar motion segments and discs in pure centric tension

In vivo creep of human lumbar motion segments and discs subject to pure centric tension is presented, in terms of aging, sex and disc level. Time-related elongations of segments L3-4, L4-5 and L5-S1 were measured during the usual 20 min long traction hydrotherapy of patients, by using a computerized subaqual ultrasound measuring method [Kurutz et al., 2002a. Orvosi Hetilap 143 (13), 673-684; Kurutz et al., 2003. Journal of Bioengineering and Biomechanics 5 (1), 67-92]. Elongation of segments was considered as a change of the distance between two adjacent spinous processes. Based on these experiments, in vivo creep of human lumbar FSUs was investigated in centric tension, in terms of sex, age and disc level. Three-parameter rheological models were used to determine viscoelastic tensile moduli of human lumbar FSUs and discs. From three time-related measured elongation values, in vivo damping constants with creep functions were calculated for each segment, in terms of sex, aging and disc level. It has been demonstrated that initial elastic elongations decrease, concerning stiffness increase with aging. Similarly, tensile creep elongations decrease, damping properties increase with aging. Former observations concerning the difference in deformation propagation of men and women in time, have been verified by means of creep analysis: although males have higher initial elastic deformability, due to a smaller damping of females, the deformation propagation of women overtakes men in creep process. This tendency is more significant with aging. Increasing damping was observed in distal direction, both for males and females.     

System of stability and lability in hydra

Summary Hydra is a unique epigenetic system where simultaneous existence of stability and lability in its cells is encountered. The two terminal ends of the hypostome and basal disc have been designated as unipotentials, in between these two points the area is bipotential, i. e. it can form either basal disc or hypostome.The dynamic state of instability in hydra has been explained on the assumption that in case of a developmental urgency the mid equipotential system can transform into either or both kinds of unipotential through the action of some inhibitory complex.Hypostome as a developmental centre is more powerful than its counter centre namely the basal disc.     

Repetitive sequences in Eurasian lynx (Lynx lynx L.) mitochondrial DNA control region

Mitochondrial DNA (mtDNA) control region (CR) of numerous species is known to include up to five different repetitive sequences (RS1-RS5) that are found at various locations, involving motifs of different length and extensive length heteroplasmy. Two repetitive sequences (RS2 and RS3) on opposite sides of mtDNA central conserved region have been described in domestic cat (Felis catus) and some other felid species. However, the presence of repetitive sequence RS3 has not been detected in Eurasian lynx (Lynx lynx) yet. We analyzed mtDNA CR of 35 Eurasian lynx (L. lynx L.) samples to characterize repetitive sequences and to compare them with those found in other felid species. We confirmed the presence of 80 base pairs (bp) repetitive sequence (RS2) at the 5' end of the Eurasian lynx mtDNA CR L strand and for the first time we described RS3 repetitive sequence at its 3' end, consisting of an array of tandem repeats five to ten bp long. We found that felid species share similar RS3 repetitive pattern and fundamental repeat motif TACAC.     

Structural analysis of repetitive DNA sequences in the bovine corticotropin-beta-lipotropin precursor gene region.

Repetitive DNA sequences in the bovine corticotropin-beta-lipotropin precursor gene region have been mapped and subjected to nucleotide sequence analysis. Two of the four repetitive DNA segments found are located in the 5'-flanking region, and one each within the intervening sequences. Each repetitive DNA segment contains one to three highly homologous unit sequences with an approximate length of 120 base pairs. All the unit sequences are flanked on the 3' side by tandem repeats. There are about 10(5) copies of the repetitive DNA in the bovine genome. Comparison of the bovine repetitive sequences with those of other mammalian species reveals the presence of a homologous segment of approximately 40 base pairs. This segment and the region preceding it in the bovine repetitive DNA exhibit sequence homology with the region encompassing the origin of DNA replication in papovaviruses.     

Ultrastructure of the intercalary disks in cardiac muscle tissue of permanent and temporary residents at high altitudes

In animals temporary adapted to the Alpine conditions, the intermembranous space of the intercalated disc is dilated 3-5 and more times, while in permanent inhabitants of the Alpine regions similar dilatation is not observed. Probably, in the latters numerous intercalated discs increase adhesive force of cardiomyocytes, extent of zones with low electrical resistance and increase contraction of myofibrills, thus promoting transmission of excitation from cell to cell.     

Measurement of geometric deformation of lumbar intervertebral discs under in-vivo weightbearing condition

Quantitative data of spinal intervertebral disc deformation is instrumental for investigation of spinal disc pathology. In this study, we employed a combined dual fluoroscopic imaging system and the MR imaging technique to determine the lumbar disc deformation in living human subjects. Discs at L2-3, L3-4 and L4-5 levels were investigated in 8 normal subjects. The geometric deformation of the discs under full body weight loading condition (upright standing) was determined using the supine, non-weightbearing condition as a reference. The average maximum tensile deformation was ?21% in compression and 24% in tension, and maximum shear deformation on the disc surface reached 26%. The data indicated that different portions of the disc are under different tensile and shear deformation. Further, discs of L2-3, L3-4 and L4-5 have different deformation behavior under the physiological weightbearing condition. In general, the higher level discs have higher deformation values. The technique used in this study can be used to investigate the deformation behaviors of diseased discs as well as the efficacy of different surgical modalities at restoring normal disc deformation patterns.     

Cage size preference in rats in the laboratory

The size of an enclosure is an integral part of how well it accommodates a nonhuman animal's welfare; however, most enrichment studies concentrate on modifying the area inside the enclosure rather than enlarging it. It has been suggested that rats have little need for more cage space, but there is no empirical evidence about rats' need for space. This experiment provides preliminary evidence for the preferences of 5 male and 5 female albino rats using T-maze choices followed by 5 min dwelling times. The rats showed a moderate but significant preference for the larger of 2 cages [540 cm2 vs. 1,620 cm2; binomial z, p <.05]. When the rats shared the chosen cage with 4 familiar cage mates, their preference for the larger cage did not become any stronger [paired t[9] = -.820, p >.05]. The results suggest that rats should be given a somewhat larger space allowance but could share it with up to 4 other rats.     

Isolation of DNA markers linked to a beet cyst nematode resistance locus in Beta patellaris and Beta procumbens.

Summary In cultivated beet no useful level of resistance of the beet cyst nematode (BCN) Heterodera schachtii Schm. has been found, unlike the situation in wild species of the section Procumbentes. Stable introgression of resistance genes from the wild species into Beta vulgaris has not been achieved, but resistant monosomic additions (2n =18 + 1), diploids of B. vulgaris with an extra alien chromosome carrying the resistance locus, have been obtained. Here we describe a new series of resistant monosomic fragment addition material of B. patellaris chromosome 1 (pat-1). We further describe the cloning of a single-copy DNA marker that specifically hybridizes with a monosomic addition fragment of approximately 8 Mb (AN5-90) carrying the BCN resistance locus. This marker and another fragment-specific, single-copy DNA marker probably flank the BCN locus on the addition fragment present in the AN5-203 material, which is approximately 19 Mb in size. Furthermore, several specific repetitive DNA markers have been isolated, one of which hybridizes to AN5-90 and also to DNA from a smaller DNA segment of Beta procumbens, present in line B883, carrying a BCN resistance locus introgressed into the B. vulgaris genome. This suggests that the specific repetitive marker is closely linked to the BCN locus.     

Properties of some monkey DNA sequences obtained by a procedure that enriches for DNA replication origins.

Twelve clones of monkey DNA obtained by a procedure that enriches 10(3)- to 10(4)-fold for nascent sequences activated early in S phase (G. Kaufmann, M. Zannis-Hadjopoulos, and R. G. Martin, Mol. Cell. Biol. 5:721-727, 1985) have been examined. Only 2 of the 12 ors sequences (origin-enriched sequences) are unique (ors1 and ors8). Three contain the highly reiterated Alu family (ors3, ors9, and ors11). One contains the highly reiterated alpha-satellite family (ors12), but none contain the Kpn family. Those remaining contain middle repetitive sequences. Two examples of the same middle repetitive sequence were found (ors2 and ors6). Three of the middle repetitive sequences (the ors2-ors6 pair, ors5, and ors10) are moderately dispersed; one (ors4) is highly dispersed. The last, ors7, has been mapped to the bona fide replication origin of the D loop of mitochondrial DNA. Of the nine ors sequences tested, half possess snapback (intrachain reannealing) properties.