Joint Sites Research Articles

On optimal site assignment for relations in the distributed database environment

In a distributed database environment, the site assignment of relations is a critical issue. When the joint operations in a query involve relations over multiple sites, the site to carry out the joint operation can have a significant impact on the performance. Based on the query descriptions and arrival frequency to each site, a methodology is developed to assign relations and determine joint sites simultaneously. The methodology first decomposes queries into relation steps and then makes site assignments based on either a linear integer programming technique to minimize the amount of intersystem communication while balancing resource utilizations across systems, or a heuristic technique to minimize average response time under similar resource constraints.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Idiopathic destructive arthritis of the shoulder

IDA of the shoulder is a condition found predominantly in elderly females. Although the shoulder is primarily involved, other joints such as the hip and knee can be affected, and concurrent OA is common at other joint sites. Clinical features include voluminous, often blood-stained effusions, together with features of rotator cuff rupture and restriction of shoulder movement. Laboratory parameters are usually normal and examination of the synovial fluid reveals large amounts of basic calcium phosphate crystals. The synovium is hypertrophied and vascular and shows fibrin deposition. It contains calcified material extracellularly. An acute inflammatory infiltrate is absent. Radiographs demonstrate soft tissue swelling and subchondral sclerosis with marked bony attrition involving the acromioclavicular and glenohumeral joints, as well as the humeral head and neck. Although some aspects of the disease seem distinct, many features are shared with other types of destructive arthritis of the shoulder. The pathogenesis of this disorder is at present obscure, but it is clear that an understanding of the processes involved will provide a vital contribution to our understanding of the response of the joint to insult. With a multidisciplinary approach and adequate communication between interested workers this aim could seen be within our grasp.

Maturation of proteoglycan matrix in articular cartilage under increased and decreased joint loading. A study in young rabbits.

The right knees of 4-month-old NZW rabbits were splinted in extension for 1 to 8 weeks. Biochemical changes of the knee articular cartilage were noted after decreased (splinted leg) and increased loading (created by the shift of body weight onto the left, contralateral limb). Increased loading accelerated changes associated with maturation of articular cartilage, which include accumulation of hyaluronic acid (HA) and keratan sulfate-rich proteoglycans (KS, PG) that are tightly bound to the tissue. After 8-weeks of splinting the content of extractable PGs in the tibial medial condyle decreased. The lost material was apparently replaced by PGs with a higher degree of sulfation of the chondroitin sulfate (Ch-S) chains. Reduced loading disturbed normal maturation as evidenced by inhibition of the accumulation of KS-rich, non-extractable PGs. Collagen content increased in all samples of different joint sites and groups during the 8-week experiment. The content of extractable PGs decreased slightly, while the content of non-extractable, especially KS-rich PGs increased. The greatest changes occurred in the tibial medial condyle, where the KS content was highest.

A reappraisal of 'analgesic hip'.

Nineteen patients with hip radiographs typical of 'analgesic hip' (rapidly destructive, atrophic arthropathy involving both femoral and acetabular components) have been studied. Women predominated (14:5), and all were elderly (mean age 74 years, range 64-83 years). Destructive hip disease was unilateral in all but one case. The mean interval from symptom onset to typical x ray appearance was short (one year, range three to 24 months), and persistent pain unresponsive to drug therapy was characteristic. Screening showed no metabolic or neurological disease. Contrary to previous reports, non-steroidal anti-inflammatory drugs could not be incriminated in development of the disease. Clinical and radiographic similarity to apatite associated destructive arthritis of other large joints was striking, and occurrence of the latter, uncommon condition in five patients (five shoulders, two knees) suggests that both descriptions represent a common articular response at different joint sites.

Extra tarsal joints and abnormal cuticular polarities in various mutants ofDrosophila melanogaster.

The legs of flies from 16 different mutant strains ofDrosophila melanogaster were examined for abnormal cuticular polarities and extra joints. The strains were chosen for study because they manifest abnormal cuticular polarities in some parts of the body (10 strains) or because they have missing or defective tarsal joints (6 strains). All but three of the stocks were found to exhibit misorientations of either the bristles, hairs, or "bract-socket vectors" on the legs. The latter term denotes an imaginary vector pointing from a hairlike structure called a "bract" to the bristle socket with which it is associated. On the legs of wild-type flies nearly all such vectors point distally, as do the bristles and hairs. In the mutant flies, the most common vector misorientation is a 180° reversal. When the bract-socket vectors of adjacent bristle sites in the same bristle row point toward one another, the distance between the sites is frequently abnormally large, whereas when the vectors point in opposite directions, the interval is frequently abnormally small. This correlation is interpreted to mean that bristle cells actively repel one another via cytoplasmic extensions that are longer in the direction of the bract-socket vector than in the opposite direction. Repulsive forces of this kind may be responsible for "fine-tuning" the regularity of bristle spacing in wild-type flies.Extra tarsal joints were found in eight of the 16 strains. A ninth strain completely lacking tarsal joints appears in some cases to have an extra tibia-basitarsus joint in its tibia. Whereas the tarsi of wild-type flies contain four joints, the tarsi ofspiny legs mutant flies contain as many as eight joints. In this extreme extra-joint phenotype, four of the joints correspond to the normal wild-type joints, and there is an extra joint in every tarsal segment except the distal-most (fifth) segment. Nearly all such ectopic extra joints have inverted polarity. In other strains the extra tarsal joints are located mainly at the wild-type joint sites, and joints of this sort have wild-type polarity. The alternation of normal and inverted (extra) joints inspiny legs resembles the alternation of normal and inverted (extra) body segment boundaries in the embryonic-lethal mutantpatch, suggesting that tarsal and body segmentation may share a common patterning mechanism.

Apatite associated destructive arthritis.

Twelve patients, 11 women and one man, aged 66-83, with a distinctive type of destructive arthropathy are described. The principal joints affected were the shoulders (ten) and knees (seven). Clinical features included pain on use, large cool effusions, instability and rapid progression. Radiographs showed attrition of bone and cartilage with a paucity of reparative changes. Synovial fluids were viscous, with low cell counts, and stained positively for the presence of apatite-containing particles. Extensive calcific material was seen in the synovium of the four patients biopsied, and on the radiographs in seven. Most patients had some associated or preceding joint disorder. The literature on similar cases is reviewed, and the possible role of crystals and other aetiological factors is discussed. It is suggested that a characteristic form of large-joint atrophy can occur in elderly patients at a number of joint sites and in several different clinical settings.

EFFECT OF DIETARY SUPPLEMENTATION OF VITAMIN C ON PIG PERFORMANCE AND THE INCIDENCE OF OSTEOCHONDROSIS IN ELBOW AND STIFLE JOINTS IN YOUNG GROWING SWINE

Seventy-two, 4-wk-old weanling pigs averaging 6.9 kg were assigned to three treatments consisting of a 19% crude protein starter diet to which 0, 350 or 700 ppm vitamin C were added. After a feeding period of 44 days, the crude protein level of the diet was decreased to 16% but vitamin C supplementation continued at the same level throughout the growing-finishing phase. At approximately 90 kg body weight, pigs were slaughtered, and elbow and stifle joints were examined for soundness. Average daily gain, average feed intake and feed:gain ratios, measured for each week or for the whole period of the starter phase, were similar among pigs fed vitamin-C-supplemented diets and those fed the control diet. There were also no significant treatment differences in performance of growing-finishing pigs. Plasma vitamin C concentration of pigs, measured during the growing-finishing phase, was significantly (P &lt; 0.01) increased by dietary supplementation of vitamin C. Locomotory ability was similar between pigs fed 350 ppm supplemental vitamin C and control pigs, but appeared to be superior (P &lt; 0.05) for pigs fed 700 ppm supplemental vitamin C. Dietary supplementation of vitamin C did not reduce the incidence and severity of osteochondral lesions in the elbow and stifle joints of the pigs. The medial femoral condyle, the medial humeral condyle, and the proximal ulna were the major joint sites affected. Positive correlations were observed between average daily gain and locomotory ability scores (r = 0.45, P &lt; 0.01), and average daily gain and soundness scores of the distal humerus (r = 0.42, P &lt; 0.01). Dietary supplementation of vitamin C did not significantly influence hydroxyproline concentrations of the lateral femoral condylar cartilage. Key words: Vitamin C supplementation, plasma vitamin C, osteochondrosis, pigs, hydroxyproline

External fixation of unstable pelvic ring fractures: comparative rigidity of some current frame configurations.

The effectiveness of external fixation in the stabilisation of pelvic ring fractures was studied in a laboratory cadaveric series. Shearing displacements occurring at sacroiliac joint and symphysis pubis dislocation sites, due to simplified longitudinal loading of the sacrum in an Instron unit, were monitored using variable-impedence transducers. The rigidity of fixation was compared for the Slatis and the Bonnel single anterior frames, for coupled and uncoupled double anterior frames, and for combined anterior-plus-posterior fixation achieved with separate transfixation pin clusters, with through-and-through pin clusters, or with a posterior screw plate. The data showed that the use of posterior fixation provided greatly enhanced stabilisation compared to that achieved with anterior fixation alone. The complex double anterior frames performed only slightly better than did the simpler single anterior frames. In no case, however, was it possible to recover rigidity levels approaching those of the intact pelvis. The results suggest that the transfixation pin arrangement is the most important determinant of pelvic fixation stability, and that further investigation of posterior screw-plate fixation is warranted.

A Possible Regulatory Mechanism in RNA Processing and Its Implication for Posttranscriptional Sequence Control during Differentiation of Cell Function

1. This paper is concerned with the possible molecular mechanism for RNA processing including posttranscriptional sequence control underlying the differentiation of cell functions. 2. It was previously postulated that intramolecular double-stranded hairpin structures present at 5'- and 3'-terminal regions of a 'pre-mRNA' are key elements for RNA splicing [24]. 3. In this paper the possibility is considered that the splicing of 'pre-mRNA' can be regulated in such a way that the formation of the proper double-stranded hairpin structures is prevented by the binding of low-molecular-weight nuclear RNA (LnRNA) to the terminal regions and/or to the nucleotide sequences around the exon-intron and intron-exon joint sites of the 'pre-mRNA' molecules. 4. Complementarity assessment of nucleotide sequences of rat preproinsulin 'pre-mRNA' and rat LnRNA, i.e. Ul, showed that Ul RNA is capable of forming stable double-standard intermolecular structures around the joint sites of preproinsulin 'pre-mRNA' and may prevent the formation of intramolecular double-stranded structures required for RNA splicing. This may imply a regulatory (inhibitory) role for Ul RNA in the processing of 'pre-mRNA'. 5. A possible regulatory role of LnRNA in RNA splicing is discussed in relation to the determination of the mRNA population to be translated in the cytoplasm during differentiation of cell functions.

Nucleotide sequence complementarity between adenovirus 2-coded VA RNA and host cell pre-mRNA. A possible regulatory mechanism of cellular RNA splicing by VA RNA.

Using a computer program, complementary of nucleotide sequences was assessed between adenovirus 2-coded VA RNA and presumptive cellular and viral 'pre-mRNAs'. In this paper, the possibility is considered that the splicing of cellular 'pre-mRNA' can be regulated in such a way that the formation of the proper intramolecular double-stranded hairpin structures, key elements for RNA splicing, is prevented by the binding of VA RNAI or RNAII to the nucleotide sequences around the exon-intron and intron-exon joint sites of cellular 'pre-mRNA' molecules. Complementarity assessment showed that VA RNAI can bind to the joint sites in such a way as to form an omega shape at two separate regions around the joint sites of cellular 'pre-mRNA'. Whereas VA RNAI is not capable of binding to viral hexon 'pre-mRNA' in the same manner as it does to cellular 'pre-mRNA', the binding may occur in a different way. Such differential binding is discussed in relation to the post-transcriptional sequence selection which takes place during the late phase of adenovirus infection.

Further studies on similarity of terminal nucleotide sequences of eukaryote mRNA—A possible mechanism of RNA splicing

In the previous report (Naora, Deacon & Fry, 1979) it was pointed out that certain regions of the 5′- and 3′-terminal nucleotide sequences, which are similar to each other, of human and rabbit globin and chicken ovalbumin mRNA were present within possible double-stranded hairpin structures of a mRNA precursor. Using complete or partial nucleotide sequencing data of mouse β maj globin, silk fibroin and chicken ovalbumin chromosomal genes, the possible occurrence of double-stranded hairpin structure in the presumptive mRNA precursor (“HnRNA”) molecule has been reexamined. Assuming that both the 5′- and 3′-terminal nucleotide sequences of “HnRNA” correspond to those of mature mRNA, nucleotide matching assessment shows that the 5′- and 3′-terminal nucleotide sequences, which are similar to each other, of mouse β maj globin and chickin ovalbumin “HnRNA” can in fact be accommodated within intramolecular double-stranded structures, together with the first and last exon-intron joint sites as the complementary sequences, respectively. In particular, the 5′-terminal region of chicken ovalbumin “HnRNA” appears to be the basic element for forming a thermodynamically stable double-stranded structure with each of the 11 other exon-intron or intron-exon joint sites. It is suggested that both the 5′- and 3′-terminal specific regions of these “HnRNA” serve as the basic structural element to allow two splicing sites to stand close together and that splicing takes place at these specific regions of the HnRNA molecule. It is also proposed that a sequential splicing to form mRNA may take place at the 5′-terminal specific region of ovalbumin “HnRNA”.

Stimulation of protein--chondroitin sulfate synthesis by normal and osteoarthritic articular cartilage.

AbstractA stimulatory effect on 35S uptake of rat costal cartilage by a commercial cartilage and bone marrow extract known as Rumalon was confirmed. In addition, the preparation was found to increase35S incorporation in vitro into chondroitin sulfate by human articular cartilage from the knee joint, both normal and osteoarthritic sites. This effect was limited to young rats, but no age limitation in effect was found with human cartilage. In other in vitro studies, the augmented 35S incorporation into chondroitin sulfate was found in fractions eluted from Dowex‐1 columns; a stimulation of incorporation of 3H‐serine into protein‐polysaccharide was also found in the same fraction. The effects of 3H‐serine and 35S uptake were augmented by addition of amino acids to the incubation medium and were inhibited by puromycin. In addition, increased incorporation of 3H‐uridine into RNA was observed in the same system.