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At least 1,711 records · Page 95Linked to original sources
PubMed2005

Production of monoclonal antibodies against Chinemys reevesii turtle vitellogenin and their usage for comparison of biochemical and immunological characters of vitellogenins and yolk proteins of freshwater turtles.

Four hybridoma clones (ACV-1, -3, -4, and -5) were established for Chinemys reevesii (Reeves' turtle) vitellogenin (VTG) as a precursor protein of egg yolk and a biomarker of environmental pollution. Binding-inhibition experiments indicated that the epitopes of four mAbs were distinct. No binding of ACV-4 to C. reevesii VTG in the Western blot suggests that the epitope of ACV-4 would be dependent on the three-dimensional structure. ACV-1, -3, and -5 bound to C. reevesii VTG in the Western blot. The signal for ACV-1 and -5 disappeared by reduction of the VTG, suggesting that the construction of the epitopes for ACV-1 and -5 were dependent on the disulfide bridge in the VTG molecule. All four mAbs recognized Trachemys scripta and Mauremys japonica VTGs in the ELISA. The yolk proteins were tested for the binding of the mAbs in the Western blot. ACV-1 being capable to bind to the VTG in the reduced condition did not bind to any protein bands of the yolk. This indicates that ACV-1 recognizes a part of the VTG molecule that is not incorporated in the oocytes. Both ACV-3 and -5 bound to the 32- and 70-kDa yolk proteins. Since a mAb recognizes only one site (epitope) on a protein molecule, the 32-kDa protein originated from the 70-kDa one. An ELISA system using ACV-5 as the capture antibody and ACV-3 as the detecting antibody showed the lower detectable concentration (2 ng/mL) and a wide detectable range to 1000 ng/mL (R2=0.999). The system was used to determine serum VTG levels of juvenile turtles treated with estradiol-17beta or vehicle (corn oil). By the use of the mAbs described in this paper, basic and applied studies for turtle VTGs would be improved.

Animals↗
PubMed2004

Radiotherapy-induced thyroid disorders.

Despite their specific functional consequences, radiotherapy-induced thyroid abnormalities remain under-estimated and underreported. These sequelae may include primary or central hypothyroidism, thyroiditis, Graves' disease, euthyroid Graves' ophthalmopathy, benign adenomas, multinodular goitre and radiation-induced thyroid carcinoma. Primary hypothyroidism, the most common radiation-induced thyroid dysfunction, affects 20-30% of patients administered following curative radiotherapy to the neck region, with approximately half of the events occurring within the first 5 years after therapy. The relative risk of radiation-induced cancer (mainly well-differentiated tumours) is 15-53-fold higher than in non-irradiated population. The aetiology of radiation-induced thyroid injury includes vascular damage, parenchymal cell damage and auto-immune reactions. Total radiotherapy dose, irradiated volume of the thyroid gland, and the extent of prior thyroid resection are among the most important factors associated with the risk of hypothyroidism. The contribution of other treatment modalities (chemotherapy, endocrine therapy) as well as patient- and tumour-related factors is less clear. Reduction in radiation dose to the thyroid gland and hypothalamic/pituitary complex should be attempted whenever possible. New radiotherapy techniques, such as stereotactic radiosurgery, three-dimensional conformal irradiation, intensity modulated radiotherapy and proton therapy allow generally better dose distribution with lower dose to the non-target organs. The diagnostic approach to thyroid radiation injury includes baseline thyroid function assays in all patients undergoing thyroid or parasellar irradiation. Recommended follow-up procedures include at least annual evaluation with a history for symptoms of thyroid dysfunction, clinical examination, and measurement of thyroid hormones and thyrotropin. Management of overt hypothyroidism is based on hormone replacement therapy. Thyroid hormone therapy is also recommended in cases of subclinical hypothyroidism. Treatment of other radiation-induced thyroid disorders (thyroiditis, Graves' disease, thyroid cancer) is similar to that employed in spontaneously occurring conditions. Further improvements in radiotherapy techniques and progress in endocrine diagnostics and therapy may allow better prevention and management of radiation-related thyroid injury.

Adenoma↗
PubMed1999

The craniofacial complex in 45,X/46,XX females.

Fourteen Finnish 45,X/46,XX females were compared with population female and male controls, and in addition, nine of them were compared with their first-degree female relatives. Linear and angular measurements were made from standardized lateral cephalograms of patients and normal population controls from the "Kvantti" study series. In both comparisons the results indicated that craniofacial dimensions in 45,X/46,XX females were smaller than those in population female and male controls. The general metric pattern was similar to that observed in relation to the tooth crowns of 45,X/46,XX females. Several of their craniofacial proportions and plane angles differed from those of normal women: shorter anterior and posterior cranial bases and a flatter cranial-base angle, a sagittally shorter maxilla and a sagittally shorter mandible with an enlarged ramus:corpus length ratio, posterior rotation of the mandible and a tendency to bimaxillary retrusion. It is suggested that the reduction of X-chromosomal genetic material in 45,X/46,XX females results in smaller craniofacial dimensions than in normal females, with substantial effects on dimensional ratios and especially plane angles of the cranial base.

Adolescent↗
PubMed1998

Effect of osmolytes on the exchange rates of backbone amide protons in proteins.

Osmolytes are small organic solutes produced by the cells of all organisms (except halobacteria) in high stress situations (e.g. extremes of salt concentration, high temperature, etc.) to stabilize their macromolecules and so conserve biological activity. They do not interact with the macromolecule directly but act by altering the solvent properties in the cellular environment, and so their presence indirectly modifies the stability of proteins. In this paper we examine the effect of a model osmolyte, glycine, on the stabilization of two proteins, chymotrypsin inhibitor 2 and horse heart cytochrome c. We have used NMR to monitor the effect of this osmolyte on amide hydrogen exchange rates, which allows a probe at discrete points within the protein structure. Hydrogen exchange rates of specific backbone amide protons provide information about the localized structural fluctuations that expose these amides to solvent and allow exchange to take place. We find that the presence of a high concentration of glycine osmolyte has a profound stabilizing effect on the proteins studied, which is accompanied by a large reduction of the exchange rate constants of most slowly exchanging amide protons. The spectra indicate that this arises without significant changes in the three-dimensional structure. However, the effects on individual amide protons within a single protein were not uniform, and a wide variation in the magnitude of the effects was observed. This ranged from no apparent change in the exchange rate, to decreases in the exchange rate constant by over 2 orders of magnitude. The osmolyte appears to alter a number of different processes that contribute to the observed exchange rates, and no simple generalization allows prediction of the extent of stabilization at any individual location. The results are discussed in light of the available structures of the proteins studied.

Animals↗
PubMed1994

[Acute pressure-dependent change in the neuroretinal rim in juvenile glaucomatous papilla. Measurement with laser scanning tomography and planimetric biomorphometry].

BACKGROUND: In glaucomatous optic disc morphology follow-up, changes due to loss of nerve fibres should be distinguished from changes without loss of nerve fibres. PATIENT AND METHOD: The intraocular pressure-dependent neuroretinal rim change in a 25-year-old white woman's optic nerve head, suffering from unilateral congenital glaucoma, had been documented papillometrically and by means of Laser Scanning Tomography. For papillometry, the optic disc outlines obtained from 15-degree stereo slides were evaluated planimetrically. To compute the volume of the optic disc excavation, 32 axially staggered optical sections were registered with a laser scanning retina tomograph (Heidelberg Engineering, Heidelberg) and computed three-dimensionally. RESULTS: At an intraocular pressure level of 9 mm Hg a diminution of the planimetrical cup to disc ratio of about 20% and a reduction of the tomographically obtained excavation volume of about 55% was seen in comparison to 44 mm Hg one day before.--After 6-month follow-up, these parameters returned to their initial readings. CONCLUSION: This phenomenon was attributed to an acute post-barotraumatic tissue edema.--To our mind, this single observation illustrates an acute change in optic disc morphology documented and quantified by laser scanning tomography.

Adult↗
PubMed1999

Large two-dimensional sonic band gaps.

We show that absolute sonic band gaps produced by two-dimensional square and triangular lattices of rigid cylinders in air can be increased by reducing the structure symmetry. In the case of square lattices, symmetry reduction is achieved by a smaller diameter cylinder placed at the center of each unit cell. For triangular lattices the reduction is achieved by decreasing the diameter of the cylinder at the center of the hexagons in the lattice. Theoretical predictions are also demonstrated experimentally: starting from a honeycomb lattice (using cylinders of 4 cm of diameter size and 6.35 cm nearest-neighbor distance) we have studied the transition to a triangular symmetry by putting rods with increasing diameter (in the range 0.6-4 cm) at the center. The greatest enhancement of the attenuation strength observed in transmission experiments has been obtained in the high frequency region for diameter ratios in the range 0.1-0.3.

Journal Article↗
PubMed2004

Quantitative evaluation of image-based distortion correction in diffusion tensor imaging.

A statistical method for the evaluation of image registration for a series of images based on the assessment of consistency properties of the registration results is proposed. Consistency is defined as the residual error of the composition of cyclic registrations. By combining the transformations of different algorithms the consistency error allows a quantitative comparison without the use of ground truth, specifically, it allows a determination as to whether the algorithms are compatible and hence provide comparable registrations. Consistency testing is applied to evaluate retrospective correction of eddy current-induced image distortion in diffusion tensor imaging of the brain. In the literature several image transformations and similarity measures have been proposed, generally showing a significant reduction of distortion in side-by-side comparison of parametric maps before and after registration. Transformations derived from imaging physics and a three-dimensional affine transformation as well as mutual information (MI) and local correlation (LC) similarity are compared to each other by means of consistency testing. The dedicated transformations could not demonstrate a significant difference for more than half of the series considered. LC similarity is well-suited for distortion correction providing more consistent registrations which are comparable to MI.

Algorithms↗
PubMed1975

Fibrin-blood platelet interaction in a contracting clot.

The interaction of fibrin and blood platelets was studied by measuring tension development in clots containing different ratios of these two components. Isometric tension attained a saturation value (MT) when plotted as a function of the concentration of either component at a constant concentration of the other. The value of MT increases linearly with the minimal platelet concentration (Ps) required in order to reach saturation at various different fibrin concentrations. A linear relationship also holds in a plot of Ps versus the logarithm of the corresponding fibrin concentration. When the cylindrical clots contracted isotonically, the velocity, normalized with respect to the momentary length, was found to be constant. This velocity decreased in an hyperbolic manner with increasing fibrin concentration at a constant concentration of blood platelets. The results are interpreted in terms of a three-dimensional network in which the blood platelets serve as contractile cross-bridges connecting fibrin fibres. Tension development is assumed to be accompanied by the reduction of the angle between fibrin fibres. An attempt was made to calculate the isometric tension developed by a platelet.

Blood Coagulation↗
PubMedDate not supplied

Computationally efficient model for simulating electrical activity in cardiac tissue with fiber rotation.

Transmural rotation of cardiac fibers may have a large influence on the initiation, stabilization, and termination of several life threatening cardiac arrhythmias. However, three-dimensional modeling of reentry in cardiac tissue is computationally demanding, as a tissue on the order of centimeters in size must be used to sustain reentry and several seconds must be simulated. Numerical accuracy requires time steps on the order of microseconds and spatial discretization on the order of microns. Consequently, the resultant numerical systems are extremely large. In this article, a computationally efficient model of a three-dimensional block of cardiac tissue with fiber rotation is presented. Computational speedup is achieved by using a discrete cable model which allowed for system order reduction, and also by using a scheme for tracking the activation wave front which identified regions requiring integration with a small time step. Simulating 1.2 s of activity of the approximately 2 x 10(6) cells constituting a block measuring 2.0 x 4.0 x 0.29 cm was performed in 26 h. Effects of model parameters on performance are discussed. The effect of fiber rotation on the spread of electrical activity after point source stimulation and a cross shock protocol is clearly demonstrated.

Action Potentials↗
PubMed1995

Structural elucidation of the lipopolysaccharide core region of the O-chain-deficient mutant strain A28 from Pseudomonas aeruginosa serotype 06 (International Antigenic Typing Scheme).

The lipopolysaccharide (LPS) of the Pseudomonas aeruginosa serotype 06 rough-type mutant A28 was isolated by a modified phenol-chloroform-petroleum ether extraction method. Deoxycholate-polyacrylamide gel electrophoresis indicated a single band with mobility similar to that of the complete core region of the wild-type parent serotype 06 (International Antigenic Typing Scheme) strain. Compositional analysis of the LPS indicated that the core oligosaccharide was composed of D-glucose (three units), L-rhamnose (one unit), 2-amino-2-deoxy-D-galactose (one unit), L-glycero-D-manno-heptose (two units), 3-deoxy-D-manno-octulosonic acid (two units), L-alanine (one unit), and phosphate (two units). Under the mild conditions of hydrolysis with methanolic hydrogen chloride, a 7-O-carbamoyl substituent was observed on the second heptose residue. The glycan structure of the LPS was determined by employing one- and two-dimensional nuclear magnetic resonance spectroscopy and mass spectrometry-based methods with a backbone oligosaccharide that was obtained from the LPS by deacylation, dephosphorylation, and reduction of the terminal glucosamine. On the basis of the results of the present study and our earlier work with the P. aeruginosa 06-derived core-defective mutant R5 (H. Masoud, E. Altman, J. C. Richards, and J. S. Lam, Biochemistry, 33:10568-10578, 1994), a structural model for the complete core oligosaccharide is proposed.

Carbohydrate Sequence↗
PubMed2002

Longitudinal myocardial contraction improves early during titration with metoprolol CR/XL in patients with heart failure.

OBJECTIVE: To investigate diastolic and systolic left ventricular recovery during titration with metoprolol CR/XL (controlled release/extended release). DESIGN: Placebo run in, followed by an open study. SETTING: University hospital. PATIENTS: 14 patients with chronic heart failure. INTERVENTIONS: Metoprolol CR/XL titrated from 12.5 mg once daily to 200 mg once daily. MAIN OUTCOME MEASURES: M mode recordings of atrioventricular (AV) plane displacement, Doppler measurement of transmitral flow and pulmonary venous flow, two dimensional ejection fraction, and measurement of venous plasma concentration of noradrenaline. Patients were investigated after 2, 4, 6, and 24 weeks of treatment. RESULTS: A reduction of heart rate was observed on the first dose (12.5 mg once daily), from a mean (SD) of 74 (11) to 67 (11) beats/min, p < 0.05. This was accompanied by prominent effects on AV plane filling parameters, including an increase in early diastolic filling period from 87 (28) to 105 (33) ms (p < 0.05), and in the lateral AV plane fractional shortening from 8.7 (2.7)% to 10.2 (2.8)% (p < 0.05). An early trend towards improvement in global systolic left ventricular function was also seen, although this was not significant until six weeks. Ejection fraction increased from 33 (7.5)% to 38 (11)% (p < 0.05). CONCLUSIONS: First effects of left ventricular recovery during beta blocker treatment were seen in recordings of longitudinal performance, as expressed by AV plane displacement. Doppler flow dynamics as well as global systolic recovery appeared several weeks later, emphasising the importance of longitudinal performance in evaluating left ventricular function.

Adrenergic beta-Antagonists↗
PubMed2004

Non-apneic snoring and the orthodontist: radiographic pharyngeal dimension changes with supine posture and mandibular protrusion.

OBJECTIVE: To evaluate the radiographic changes that occur in the pharynx and surrounding structures with alteration of posture from the upright to the supine position and the effect that mandibular protrusion whilst supine has on these dimensions. DESIGN: Prospective cephalometric study. SETTING: University Dental Hospital and School. SUBJECTS AND METHOD: This prospective study involved 35 consecutively referred adults with proven non-apneic snoring. Lateral skull radiographs were obtained with the subjects upright in occlusion, supine in occlusion and supine with the mandible protruded to the maximum comfortable position. Radiographs were traced and digitized, and the pharyngeal dimensional changes and hyoid position were examined. Males and females were examined separately. RESULTS: Radiographic pharyngeal dimensions were changed with altered posture, resulting in significant reductions in the minimum post-palatal (p<0.01) and post-lingual (p<0.05) airway measurements in the supine position. Mandibular protrusion whilst in the supine position produced increases in the functioning space for the tongue. CONCLUSION: A supine posture results in significant reductions in pharyngeal airway measurements of non-apneic snorers. Mandibular protrusion whilst in the supine position produces an increase in the functioning space for the tongue.

Adult↗
PubMed2003

Glucagon-like peptide 1 inhibits cell apoptosis and improves glucose responsiveness of freshly isolated human islets.

The peptide hormone, glucagon-like peptide 1 (GLP-1), has been shown to increase glucose-dependent insulin secretion, enhance insulin gene transcription, expand islet cell mass, and inhibit beta-cell apoptosis in animal models of diabetes. The aim of the present study was to evaluate whether GLP-1 could improve function and inhibit apoptosis in freshly isolated human islets. Human islets were cultured for 5 d in the presence, or absence, of GLP-1 (10 nm, added every 12 h) and studied for viability and expression of proapoptotic (caspase-3) and antiapoptotic factors (bcl-2) as well as glucose-dependent insulin production. We observed better-preserved three-dimensional islet morphology in the GLP-1-treated islets, compared with controls. Nuclear condensation, a feature of cell apoptosis, was inhibited by GLP-1. The reduction in the number of apoptotic cells in GLP-1-treated islets was particularly evident at d 3 (6.1% apoptotic nuclei in treated cultures vs. 15.5% in controls; P < 0.01) and at d 5 (8.9 vs. 18.9%; P < 0.01). The antiapoptotic effect of GLP-1 was associated with the down-regulation of active caspase-3 (P < 0.001) and the up-regulation of bcl-2 (P < 0.01). The effect of GLP-1 on the intracellular levels of bcl-2 and caspase-3 was observed at the mRNA and protein levels. Intracellular insulin content was markedly enhanced in islets cultured with GLP-1 vs. control (P < 0.001, at d 5), and there was a parallel GLP-1-dependent potentiation of glucose-dependent insulin secretion (P < 0.01 at d 3; P < 0.05 at d 5). Our findings provide evidence that GLP-1 added to freshly isolated human islets preserves morphology and function and inhibits cell apoptosis.

Apoptosis↗
PubMed2004

Identification of autoantibodies with the corresponding antigen for repetitive coxsackievirus infection-induced cardiomyopathy.

BACKGROUND: The hypothesis that viral myocarditis causes an autoimmune response and subsequent dilated cardiomyopathy is controversial. To further investigate the autoimmune mechanism of cardiac dilatation and dysfunction after repeated episodes of viral myocarditis, the cardiac autoantigens induced by repetitive coxsackievirus B3 (CVB3) infection were examined. METHODS AND RESULTS: Male inbred A/J mice were inoculated intraperitoneally with CVB3 at 3 and 40 weeks of age. At 8 weeks after the second inoculation, the mortality of the repetitive CVB3 group was significantly increased compared with that of the control group, and was associated with a significant reduction in fractional shortening and marked left ventricular dilatation without inflammatory cell infiltration. The cardiac antigens in the repetitive CVB3 infection were identified by 2-dimensional electrophoresis and subsequent liquid chromatography/tandem mass spectrometry (LC-MS/MS) using the serum at 2 weeks after the second inoculation. LC-MS/MS and immunohistochemistry demonstrated alpha-cardiac actin and heat shock protein 60 (HSP60) as cardiac near-surface antigens induced by the repetitive CVB3 infection. Immunoelectron microscopy disclosed the selective localization of anti-IgM antibody on the membrane of the myocytes in the repetitive CVB3 group. CONCLUSIONS: IgM antibodies against alpha-cardiac actin and HSP60, which were induced by repetitive CVB3 infection, may play an important role in the pathophysiology of the subsequent cardiac dysfunction and dilatation.

Animals↗
PubMed2005

Characterization of gradient-index lens-fiber spacing toward applications in two-photon fluorescence endoscopy.

We report on the experimental investigation into the characterization of two-photon fluorescence microscopy based on the separation distance of a single-mode optical fiber coupler and a gradient-index (GRIN) rod lens. The collected two-photon fluorescence signal exhibits a maximum intensity at a defined separation distance (gap length) where the increasing effective excitation numerical aperture is balanced by the decreasing confocal emission collection. A maximum signal is found at gap lengths of approximately 2, 1.25, and 1.75 mm for GRIN lenses with pitches of 0.23, 0.25, and 0.29 wavelength at 830 nm. The maximum two-photon fluorescence signal collected corresponds to a threefold reduction of axial resolution (38.5 microm at 1.25 mm), compared with the maximum resolution (11.6 microm at 5.5 mm), as shown by the three-dimensional imaging of 10 microm beads. These results demonstrate an intrinsic trade-off between signal collection and axial resolution.

Journal Article↗
PubMed2000

Biological repair of thyroid cartilage defects by osteogenic protein-1 (bone morphogenetic protein-7) in dog.

The efficacy of human recombinant osteogenic protein-1 (OP-1; bone morphogenetic protein-7) in regeneration of dog larynx was examined by treating thyroid cartilage defects (1.5 cm2) in dogs with thyroid allografts covered with host perichondrium or fascia. Prior to implantation allografts were frozen, thawed and demineralized. The treatment groups were as follows: I--Allograft control implant (n = 3); II--Implants coated with 500 micrograms OP-1 (n = 4); III--Implants coated with 100 micrograms OP-1 (n = 3); IV--Implants coated with 500 micrograms OP-1 and covered with neck fascia (n = 3); and V--Implants extracted with 1 M NaCl and guanidine hydrochloride, and coated with 500 micrograms OP-1 (n = 4). Dogs were sacrificed four months following surgery. Each larynx was removed, carefully dissected and a three-dimensional reconstruction of the defect area was performed on serial sections. The results revealed that the implants of control dogs remained intact with no apparent reduction in size and new tissue formation. OP-1 enriched thyroid allografts, dose dependently induced bone, cartilage and ligament-like structures comprising up to 80% of the total regenerated defect area. Boundaries of the defects healed by formation of new bone when bone resided within the old thyroid cartilage layers. Old cartilage not containing bone within its layers healed by complete integration with newly formed cartilage. Both new bone and cartilage were embedded into layers of new ligament-like tissue which expressed specific morphologic and molecular markers. The three newly formed tissues were tightly connected into a "bone-cartilage-ligament continuum" of tissues, suggesting that OP-1 served as a multiple tissue morphogen in this specific microenvironment.

Animals↗
PubMedDate not supplied

Electrocatalytic treatment of waste: studies on discoloration of an industrial azo dye effluent.

A textile dye effluent containing chiefly reactive azo dyes has been treated electrochemically for discoloration and COD (chemical oxygen demand) reduction at different current densities, flow rates and dilution. Experiments have been carried out in a thin electrochemical reactor under single pass conditions using a dimensionally stable catalytic anode (DSA) and a stainless steel cathode.

Azo Compounds↗
PubMed1990

Sulfatide-binding domain of the laminin A chain.

A sulfatide-binding site on the globular end region of the long arm of laminin has been identified. Following proteolytic digestion with thermolysin, an intact fragment of the laminin A chain carboxyl-terminal domain exhibiting sulfatide-binding activity was isolated using gel filtration and heparin affinity chromatography. This fragment is composed of two peptides that are covalently linked by at least one disulfide bond and encompass the carboxyl-terminal 394 amino acids of the A chain. The clusters of charged residues in the primary structure of these fragments are sufficient for heparin-binding activity but not sulfatide binding since reduction and alkylation of the fragments abolished sulfatide binding under conditions in which heparin binding was retained. Thus, sulfatide binding requires an intact three-dimensional structure. The iodinated fragment bound to A2058 melanoma and T47D breast carcinoma cells and could be displaced by the unlabeled fragment. Based on incorporation of [35S] sulfate, both cell lines synthesize sulfated glycolipids that bind to laminin. In agreement with previous data that indicate a synergistic interaction of the sulfatide-binding domain with other laminin-binding sites on melanoma cells during attachment, the isolated sulfatide-binding fragment significantly inhibited interaction of labeled intact laminin with melanoma and breast carcinoma cells in direct binding assays.

Amino Acid Sequence↗