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PubMed2006

Cooperation of EB1-Mal3 and the Bub1 spindle checkpoint.

EB1 is a conserved microtubule binding protein that preferentially localizes to the growing tips of the microtubule plus end. Whilst the function of EB1 in cell polarity control is well established, its role during mitosis remains largely elusive. Here we discuss our recent work of roles for Mal3, the fission yeast EB1 homologue, in mitotic progression and chromosome stability. Our analysis sheds light upon the requirement of Mal3 for bipolar microtubule attachment and its cooperative role with the spindle assembly checkpoint. In particular Mal3 collaborates with a specific branch of this checkpoint pathway, which is dependent upon Bub1, but not Mad2. As malfunctioning of the EB1-mediated pathway might be directly related to chromosome instability in some types of human cancers, a new knowledge of Mal3's mitotic role would be of direct relevance to understanding the molecular defects in these cancer cells.

Animals↗
PubMed1999

[Factors influencing bone mineral density around the femoral stem after cementless total hip arthroplasty].

Factors influencing bone mineral density around the femoral stem after PM cementless total hip arthroplasty were evaluated in longitudinal study of 18 hips in 18 patients who had undergone surgery due to unilateral hip osteoarthritis. Bone mineral density in the femoral neck was determined by dualenergy X-ray absorptiometry measurement performed preoperatively and in periprosthetic femoral Gruen's zones prospectively 2 weeks, 3, 6, 12 and 24 months after surgery. The concentrations of calcium, magnesium and fluoride were measured in cortical and trabecular bone samples taken from resected femoral head and neck. At 12 and 24 months after the operation the regional bone mineral density measurement showed significant, maximum decrease but after 12 months bone mineral density appeared to be stabilized. The analysis of preoperative femoral neck density and fluoride content in trabecular bone proved that osteopenia and lower fluoride concentrations correlated significantly with greater bone density decrease after total hip arthroplasty. No other factors (age, sex, weight, calcium and magnesium concentrations in bone and fluoride concentration in cortical bone) showed significant associations.

Adult↗
PubMed2001

[Gait disorders in Parkinson disease. Clinical description, analysis of posture, initiation of stabilized gait].

A WELL INFORMED DESCRIPTION: The parkinsonian posture is generally described as a stooped one. At the beginning of the disease, the gait troubles remain moderate; gradually the gait is composed of small steps without a wide base; the patient tends to run after his centre of gravity by accelerating the step (festination phenomenon). Difficulties occurs for starting up (delay of gait initiation), for about-turn or for clearing obstacles. Kinetic jammings and standing around (freezing) can last several seconds and be responsible for falls. POSTURAL INSTABILITY, A MAJOR SYMPTOM IN PARKINSON'S DISEASE: This symptom is little improved by therapies and is responsible for serious disability. Postural instability induces a disequilibrium and is partially due to a simultaneous antagonist muscles contraction and to the impossibility of modifying postural responses to changing support conditions. The passive viscoelastic properties of muscles and tendons constitute a first line of defence against the disequilibrium and contribute to postural stability in the case of medium disturbances. Automatic and voluntary postural responses which come into play in the case of major disturbances can also be impaired (delay or defect of the responses). GAIT INITIATION FAILURE ARE FREQUENT: They result from an increase of the postural phase and a decrease of the propulsion forces, depending on a deficit of the postural anticipation mechanisms and also the sequential organization and the integration of two different motor programs, postural and locomotor. They can be controlled partially with sensory stimuli, notably visual inputs. DATA CONCERNING STABILIZED WALKING AND ITS PATHOPHYSIOLOGY REMAINS TO BE CLARIFIED: Spatial and temporal parameters are impaired: speed, step length and swing phase are reduced, while cadence increases to compensate these troubles. These modifications are the consequence of an incapacity to produce internal marks to generate regular steps. When the parkinsonian patient is supplied with external marks, these parameters can be normalized. From a pathophysiological point of view, gait disorders could result from defective central integration of proprioceptive information during movement within the basal ganglia, associated with a visual perceptive deficit linked with a retinal dopaminergic cells dysfunction and finally from an impairment of the proprioceptive feedback of the load receptors in the leg extensor muscles.

Antiparkinson Agents↗
PubMedDate not supplied

Routine analysis of ascorbic acid in citrus juice using capillary electrophoresis.

A procedure to monitor citrus juice samples was established to quantitate vitamin C by capillary electrophoresis using a previously developed method. Dilution and filtration were the only preparation requirements and separation was achieved with an uncoated capillary using a 35mM sodium borate buffer (pH 9.3) containing 5% (v/v) acetonitrile at 21 kV and 23 degrees C. Detection was performed by high speed scanning between 200 and 360 nm. From the multiwave length scan, the electropherogram at 270 nm was extracted and used to quantitate ascorbic acid. The ascorbic acid concentration was calculated with an internal standard method, with ferulic acid as internal standard. The level of ascorbic acid during analysis was stabilized with ethylenediaminetetraacetic acid and dithiothreitol was used to reduce dehydroascorbic acid to ascorbic acid to estimate the total vitamin C level. Results were similar to those obtained by liquid chromatography and the method is now used to determine routinely the level of ascorbic acid in citrus juices.

Acetonitriles↗
PubMed1979

[Cryoglobulin analysis by ultracentrifugation in density stabilized gradient followed by immunodiffusion (author's transl)].

A technique is described which combines ultracentrifugation in a density gradient stabilized by gelification, with agar gel immunodiffusion. The use of this procedure to determine sedimentation parameters and antigenic determinations is presented and illustrated with the diagramms obtained in the identification of various cryoglobulins.

Centrifugation, Density Gradient↗
PubMed2001

[Environment of tryptophan residues in proteins--a factor for stability to oxidative nitrosylation. I. Analysis of primary structure].

Micellar catalysis under aerobic conditions effectively accelerates oxidative nitrosylation because of solubilization of NO and O2 by protein membranes and hydrophobic nuclei. Nitrosylating intermediates NOx (NO2, N2O3, N2O4) form mainly in the hydrophobic phase, and therefore their solubility in aqueous phase is low and hydrolysis is rapid, local concentration of NOx in the hydrophobic phase being essentially higher than in aqueous. Tryptophan is a hydrophobic residue and can nitrosylate with the formation of isomer N-nitrosotryptophans (NOW). Without denitrosylation mechanism, the accumulation of NOW in proteins of NO-synthesizing organisms would be constant, and long-living proteins would contain essential amounts of NOW, which is however not the case. Using Protein Data Bank (more than 78,000 sequences) we investigated the distribution of tryptophan residues environment (22 residues on each side of polypeptide chain) in proteins with known primary structure. Charged and polar residues (D, H, K, N, Q, R, S) are more incident in the immediate surrounding of tryptophan (-6, -5, -2, -1, 1, 2, 4) and hydrophobic residues (A, F, I, L, V, Y) are more rare than in remote positions. Hence, an essential part of tryptophan residues is situated in hydrophilic environment, which decreases the nitrosylation velocity because of lower NOx concentration in aqueous phase and allows the denitrosylation reactions course via nitrosonium ion transfer on nucleophils of functional groups of protein and low-molecular compounds in aqueous phase.

Amino Acid Sequence↗
PubMed2001

[Expression of the chiA gene from Serratia marcescens in both strain E26 and strain NG13, nitrogen-fixing bacteria associated with rice root].

A 1.8 kb HinfI fragment carrying the chitinase gene (chiA) from Serratia marcescens was cloned into the expression vector pKK223-3 and the plasmid pMC71A, yielded the plasmid pKChiA and the plasmid pMChiA respectively. Both plasmid pKChiA and plasmid pMChiA were used to transform to the Enterobacter cloacae strain E26 and the Klebsiella oxytoca strain NG13, two nitrogen-fixing bacteria associated with rice root. The chiA gene could be highly expressed in the ChiA+ transformants of the strain E26 or the strain NG13. Cell location determination of the expressed chitinase showed that the enzyme existed not only in cell periplasm and cytoplasm, but also in extracellular broth. When the cultures were in the aftor logarithmic growthe phase, the distribution of the enzyme activity in extracellular broth, periplasm and cytoplasm were 23%-28%, 45%-51% and 21%-32%, respectively. The molecular weight of chitinase expressed in the ChiA+ transformants was 58 kD by SDS-PAGE analysis. The stability of the plasmid pMChiA in the transformants was better than that of the plasmid pKChiA.

Chitinases↗
PubMedDate not supplied

Spontaneous mandibular fracture in a partially edentulous patient: case report.

This article describes the case of a 78-year-old patient whose mandibular fracture was treated with miniplate osteosynthesis. After initial treatment, panoramic radiography revealed a fracture of the miniplate, and at follow-up, a loosening of the replacement plate. For the dental practitioner, this clinical case highlights the importance of panoramic radiography and occlusal analysis and stabilization for diagnosis of mandibular fracture, evaluation of miniplate fracture and treatment, especially in the absence of trauma.

Aged↗
PubMed1992

[Monomerization of the fragment D dimer of stabilized fibrin by a secretion from the medicinal leech salivary gland].

The salivary gland secretion of the medicinal leech catalyzes the conversion into monomeric form of the fragment D dimer, the product of limited proteolysis of stabilized fibrin. Analysis of N-terminal sequences revealed identical fragments for the D-dimer gamma-gamma-chains and the D-monomer gamma-chains formed via this reaction and established the presence of only one N-terminal amino acid (Ser). These results provide evidence for the preservation of integrity of the polypeptide chains during monomerization of the D-dimer.

Amino Acid Sequence↗
PubMed1992

trp repressor/trp operator interaction. Equilibrium and kinetic analysis of complex formation and stability.

The trp repressor of Escherichia coli regulates transcription initiation in the trp operon by binding at an operator located within the trp promoter region. We have used a filter binding assay to analyze the interaction between purified trp repressor and a synthetic 43-base pair DNA fragment containing the natural trp promoter-operator region. In equilibrium binding experiments, the KD of high affinity binding of trp repressor to this DNA fragment was determined to be 2 x 10(-10) M. Low affinity binding was observed at repressor concentrations above 10 nM. In kinetic experiments with various input ratios of repressor to operator, trp repressor-operator complexes dissociated with equivalent, first-order kinetics. Instantaneous reduction of the tryptophan concentration resulted in increased rates of complex dissociation, indicating that loss of one or both tryptophan molecules from the repressor-operator complex destabilizes the complex. A heterodimeric repressor with a single tryptophan binding site was constructed and its affinity for operator was compared with that of ligand free aporepressor and tryptophan saturated repressor. The heterodimeric repressor had a 20-25-fold higher affinity for operator than did the aporepressor, and it had a 20-25-fold lower affinity for operator than did the tryptophan-saturated repressor.

Bacterial Proteins↗
PubMedDate not supplied

[Seasonality of birth in schizophrenia patients. Literature review].

Schizophrenia is a major public health problem. The paper presents a review of the literature about seasonality of birth in schizophrenia. Tramer (1929) reported the first study on seasonality of birth in mental disorders. Seasonality of the birth of people who develop schizophrenia refers to a 5-8% excess of births in winter months. However, the peak of research into this phenomenon started in the 1990's. Torrey et al. (1997) reviewed over 250 studies from 29 countries in the Northern Hemisphere and 5 publications by authors from the Southern Hemisphere, concerning the relationship between birth seasonality and the incidence of schizophrenia. The research findings from the Northern Hemisphere were consistent, indicating a 5-8% increase in the risk for mental disorders in individuals born between December and May. Meta-analysis of investigations from the Northern Hemisphere indicates that seasonality of birth increases with geographical width. Results of research from other geographical areas, analysis of stability of this phenomenon during decades and attempts of explanation of seasonality are presented.

Birth Rate↗
PubMed1991

[Various results of the study of medico-biological aspects of alcoholism in Siberia and Far East].

To study the dynamic changes in alcohol abuse, a new methodological approach has been developed which implies staged realization. Stage one was aimed at the search for integral clinical-dynamic characteristics as well as social and psychological properties to make identification of the clinical phenotype reliable. Stage II--at introduction of integral constitution-morphology indicators representative of the disease predisposition-stability. The analysis of medicosocial characteristics for the last 8 years has been performed at Stage III. Calcium homeostasis and related hormones and enzymes were evaluated at Stage IV. The data obtained permitted identification of a complex of structural manifestations underlying alcohol embryopathy of the brain.

Alcoholism↗
PubMed2006

[Survey on the current situation of the young neurologists in Spain: analysis of their current working stability and degree of social protection].

INTRODUCTION: The aims of this study were to evaluate the working stability and degree of social protection of the Spanish young neurologists, and to know their opinion about their own situation. METHODS: The 343 neurologists that became specialists in Spain between 2000 and 2004 were asked to participate in two consecutive surveys. The first, conducted online, included questions about the availability to change the place of work and the opinion about the situation of young neurologists, and obtained 66 answers. The second was a telephonic and online survey, answered by 217 neurologists, whose questions referred to: places of neurological education and work, type of working contract, and degree of social protection (estimated by the percentage of worked time during which they paid Social Security contributions). RESULTS: Sixty-three per cent (136/217) of the Spanish young neurologists had an unstable job. The most frequent unstable working contracts were: eventual (n=65; 31%), on-call contracts (n=54; 25%) and grants (n=53; 24%). Forty-eight per cent of the neurologists who ended their specialization in 2000 still remained working-unstable. The mean percentage of worked time with full social protection was 71.01+/-36.74%. Less than a half (n=101; 46%) had social protection during the entire worked time, 60 (28.6%) were socially protected during <50% of the worked time, and 23 (11%) never had social protection. A direct relationship was observed 68 between working instability and lower social protection (p=0.0002). The working situation of the Spanish young neurologists was seen as problematic by 97% of the 66 participants in the first survey. CONCLUSIONS: The current situation of the Spanish young neurologists, attending their working stability and degree of social protection, seems precarious and problematic. Urgent actions should be taken by the Administration to improve it.

Data Collection↗
PubMed2006

A comparative biomechanical analysis of implants for the stabilization of proximal humerus fractures.

A new humerus nail (Sirus) has become available for the treatment of fractures of the proximal humerus. The aim of the study was the biomechanical comparison of this implant with established systems. 12 matched pairs of human humeri were employed for testing. Three randomized groups were formed (n = 4 pairs). A bending moment of 7.5 Nm and a torsional moment of 8.3 Nm were applied in a test of five loading cycles to all intact bones. Loading was consistently initiated at the distal epiphysis. The consequent deformation at the distal epiphysis was continuously recorded. Then an osteotomy with a defect of 5 mm was created to simulate an unstable subcapital humerus fracture. For paired comparison, one of each pair was stabilized with the Sirus proximal humerus nail. The other side was fixed with a reference implant. The following groups were created.: Group I: Sirus versus Proximal humerus nail (PHN) with spiral blade. Group II: Sirus versus PHILOS plate. Group III: Sirus versus 4.5 mm AO T-plate. The proximal humerus nail (Sirus) demonstrated significantly higher stiffness values than the reference implants for both bending and torsional load. The following values were recorded at a bending moment of 7.5 Nm: Sirus 14.2 mm, PHN 20.7 mm, PHILOS plate 28.1 mm, 4.5 AO T-plate 29.3 mm p < 0.0012). The values at 8.3 Nm torsional moment were: Sirus 8.5 degrees , PHN 12.3 degrees , PHILOS plate 16.4 degrees , 4.5 AO T-Platte 15.6 degrees (p < 0.002). The intramedullary load carriers were biomechanically superior when compared to the plating systems in the fracture model presented here. Supplementary, the Sirus Nail showed higher stiffness values than the PHN. However, the latter are gaining in importance due to the possibility of minimal invasive implantation. Whether this will be associated with functional advantages requires further clinical investigation.

Biomechanical Phenomena↗
PubMed1990

Kinetics and mechanism of DNA repair. Preparation, purification and some properties of caged dideoxynucleoside triphosphates.

Caged dideoxyribosylthymine triphosphate, dideoxyadenosine triphosphate and arabinosylcytosine triphosphate were prepared in high yield by reaction with 1-(2-nitrophenyl)diazoethane at pH 4 and room temperature for 24 h. Synthesis of caged alpha-32P-labelled dideoxyadenosine triphosphate (approx. 5000 Ci/mmol) in 85% yield was achieved by a modification of the method used for the synthesis of the unlabelled compounds. ATP was shown to be an excellent buffer in the synthesis of alpha-32P-labelled material, and in caged form to be an effective carrier in h.p.l.c. purification. Preparative h.p.l.c. was used to achieve purification of unlabelled caged compounds to greater than 98% purity and 32P-labelled material to 97% purity. Photolysis of unlabelled and 32P-labelled caged compounds by using XeF-excimer laser irradiation at 351 nm was characterized by using difference spectrophotometry and h.p.l.c. analysis. The stability of caged dideoxyadenosine [a-32P]triphosphate in the presence of cultured mammalian cells was evaluated; the adenosine derivative is essentially stable for 1 h.

Animals↗
PubMed1989

[Outcome of the surgical treatment of spondylolisthesis].

The authors present their analysis of stability of the "scoliotic arch--Tarrington's distractor" system in various versions of surgical stabilization. A modification of Tarrington's technique is suggested which improves the initial fixation strength and reduces the risk of complications.

Adolescent↗
PubMed1989

[Computed tomography of spinal injuries].

Computed tomography images are free of superpositional effects. Therefore, today CT represents the most effective method of evaluating spinal fractures. Clear imaging of the vertebral elements provides a sufficient analysis of stability in most cases. Moreover, in the polytraumatized patient, every region of the body can be evaluated without new positioning. Thus, the sequence of therapy may become obvious within a reasonable amount of time. The 3-column theory has proved to be very effective for evaluation of the remaining stability in spinal fractures.

Fractures, Bone↗
PubMed1986

The systematic characterization by aqueous column chromatography of solutes which affect protein stability.

We have systematically characterized, by aqueous column chromatography on a size exclusion cross-linked dextran gel (Sephadex G-10), 12 solutes, 11 of which are known to affect protein stability. Six are chaotropes (water structure breakers) and destabilize proteins, while five are polar kosmotropes (polar water structure makers) and stabilize proteins. Analysis of the chromatographic behavior of these neutral (ethylene glycol, urea), positively charged (Tris, guanidine, as the hydrochloride salts) and negatively charged (SO2-4, HPO2-4, F-, Cl-, Br-, Cl3CCO-2, I-, SCN-, as the sodium salts, in order of elution) solutes at pH 7 as a function of sample concentration (up to 0.6 M), supporting electrolyte, and temperature yields four conclusions, based largely on the behavior of the anions. Chaotropes adsorb to the gel according to their position in the Hofmeister series, with the most chaotropic species adsorbing most strongly. ++Chaotropes adsorb to the gel less strongly in the presence of chaotropes (a salting in effect) and more strongly in the presence of polar kosmotropes (a salting out effect). Polar kosmotropes do not adsorb to the gel, and are sieved through the gel according to their position in the Hofmeister series, with the most kosmotropic species having the largest relative hydrodynamic radii. The hydrodynamic radii of polar kosmotropes is increased by chaotropes and decreased by polar kosmotropes. These results suggest that a chaotrope interacts with the first layer of immediately adjacent water molecules somewhat less strongly than would bulk water in its place; a polar kosmotrope, more strongly.

Amidohydrolases↗