Characterization of a large glycoprotein proteoglycan by size-exclusion chromatography combined with light and X-ray scattering methods.

The molecular weight and chain conformation of a proteoglycan derived from shark cartilage in solution were characterized by size-exclusion chromatography combined with low-angle laser light scattering and small-angle X-ray scattering methods. The total molecular weight of the proteoglycan was 3.9±0.

Development of a sleep apnea event detection method using photoplethysmography.

We studied the possibility of detection of sleep apnea or hypopnea events from photoplethysmography (PPG) wave variation patterns during sleep. In three patients with suspected sleep apnea syndrome, polysomnography (PSG) and the PPG wave were measured simultaneously during sleep. The characteristics of the PPG wave variation patterns in apnea or hypopnea events detected by PSG were investigated.

Further application of size-exclusion chromatography combined with small-angle X-ray scattering optics for characterization of biological macromolecules.

Size-exclusion chromatography (gel filtration chromatography or gel permeation chromatography) in conjunction with online synchrotron radiation solution small-angle X-ray scattering optics, absorbance, and/or refractive index detectors was further assessed by application of biological macromolecules, such as the hollow sphere protein complex, apoferritin, and a linear polysaccharide, pullulan. The net X-ray scattering patterns of the eluted 24-mer molecule of apoferritin showed the specific character for the hollow spherical shape. The chromatographic (time-resolved) X-ray scattering data of the linear polysaccharide pullulan revealed the flexible chain structure during the chromatographic separation in an aqueous solution.

Structural properties of silkworm small heat-shock proteins: sHSP19.9 and sHSP20.8.

sHSP20.8 and sHSP19.9 are silkworm small-heat shock proteins (sHSPs) comprising a number of polypeptides of molecular sizes of several tens of kilodaltons as subunits.

Influence of oral appliances on craniocervical posture in obstructive sleep apnea-hypopnea syndrome patients.

Purpose: The existence of a relationship between head posture and mandibular function has been discussed by several authors. However, the relationship between head posture and the cervical spine in patients with obstructive sleep apnea-hypopnea syndrome (OSAHS) who are using oral appliances (OAs) remains unknown. The aim of this study was to evaluate the changes in the cervical spine associated with the use of OAs in patients with OSAHS.

Size-exclusion chromatography combined with small-angle X-ray scattering optics.

Size-exclusion chromatography with on-line synchrotron radiation solution small-angle X-ray scattering optics, absorbance and/or refractive index detectors was evaluated by protein characterizations. The radius of gyration value and zero-angle scattering intensity of protein molecules eluted from the chromatography column were estimated using this measurement system. In addition, the characterization of the conformation of the eluted proteins was demonstrated for hen egg lysozyme and bovine submaxillary mucin.

Reassembly of an integral oligomeric membrane protein OmpF porin in n-octyl beta-D: -glucopyranoside-lipids mixtures.

The denatured monomers of an integral membrane protein OmpF porin were refolded and reassembled into its sodium dodecyl sulfate-resistant trimer in mixtures of n-octyl beta-D: -glucopyranoside and lipids. Effective reassembly was observed with a yield of 60-70% when the denatured monomers (0.1 mg/mL) were solubilized at 25 degrees C for 24 h in a refolding medium (pH 6.

Physicochemical characterization of the reassembled dimer of an integral membrane protein OmpF porin.

The in vitro reassembled species of OmpF porin, which was renatured from its denatured monomer using n-octyl-beta-D-glucopyranoside, was characterized by low-angle laser light scattering photometry, circular dichroism spectroscopy and synchrotron radiation small-angle X-ray scattering measurements. The light scattering measurement reconfirmed that the reassembled species was the dimer of the protein. Circular dichroism spectra of the reassembled dimer showed a native-like beta-structure.

[The effectiveness of prosthodontic mandibular advancement for obstructive sleep apnea syndrome].

Purpose: This study investigated the hypothesis of a direct association between the shift of incisal point and the diameter of the oropharynx space, and nocturnal oximetry with and without prosthodontic mandibular advancement (PMA) which is one type of oral appliance used to treat obstructive sleep apnea syndrome (OSAS), and to indicate the effects of PMA.

Methods: A total of 19 patients with OSAS were subjected to finger pulse oximetry recording and lateral cephalometric radiography: with and without PMA. The distance of the oropharynx space (PNS-AS, SPAS, MAS, and IAS) and the shift of incisal point with PMA were measured.

Structural characterization of lactate dehydrogenase dissociation under high pressure studied by synchrotron high-pressure small-angle X-ray scattering.

The effect of high pressure on lactate dehydrogenase (LDH) was studied using small-angle X-ray scattering (SAXS). The SAXS results are interpreted in terms of the dissociation and association of LDH within a compression and decompression cycle and its temperature dependence. LDH consists of four identical subunits.

The hydration of Ras p21 in solution during GTP hydrolysis based on solution X-ray scattering profile.

The small-angle X-ray scattering technique was used to characterize the structure in solution of wild type ras p21 as well as the oncogenic proteins mutated at residue 12, 59, or 61. In the presence of GDP, the radius of gyration, Rg, determined for wild type ras p21 was 16.89 +/- 0.

X-ray scattering study of the shape of the DNA region in nucleosome core particle with synchrotron radiation.

The structure of the DNA region in rat thymus nucleosome core particle has been studied by synchrotron X-ray scattering analysis and the contrast-variation technique has been applied to determine the contribution of the DNA to the total scatterings. Small-angle contrast-matching measurements show that the entire core particle and isolated histone octamers are contrast-matched by solvents containing 64 and 54% (w/w) sucrose, respectively. At a contrast of 54% sucrose, where the scattering of the DNA dominates, the scattering data extending to higher angle of about 0.

Synchrotron X-ray scattering study of chromatin condensation induced by monovalent salt: analysis of the small-angle scattering data.

Small-angle X-ray scattering experiments were carried out on rat thymus chromatin in "native" and "H1-depleted" states at various NaCl concentrations using synchrotron radiation. From the analysis of cross-sectional Guinier plots, the radius of gyration of the cross section (Rc) and the mass per unit length (Mc) of native chromatin were evaluated. In the absence of NaCl, the cross section of chromatin filament has a radius of gyration of 3.

X-ray scattering study on hemoglobin solution with synchrotron radiation: a simple analysis of scattering profile at moderate angles in terms of arrangement of subunits.

X-ray scattering profiles in moderate-angle regions were recorded from carbon-monoxy-, oxy-, and deoxyhemoglobin solutions, using synchrotron radiation. They all display four distinct scattering peaks at R = 0.030, 0.

Aggregation of bovine serum albumin upon cleavage of its disulfide bonds, studied by the time-resolved small-angle X-ray scattering technique with synchrotron radiation.

A rapid mixing system of the stopped-flow type, used with small-angle X-ray scattering equipment using synchrotron radiation, is described. The process of aggregation of bovine serum albumin was traced with a time interval of 50 s, initiated upon cleavage of its disulfide bonds by reduction with dithiothreitol. The results indicate that a 218-fold molar excess of dithiothreitol over the number of moles of disulfide bonds in bovine serum albumin is sufficient to initiate the reaction immediately after mixing, which reaches equilibrium in about 15 min.

Time-resolved small-angle X-ray scattering experiment on association of isolated alpha- and beta-chains of human hemoglobin.

The time course of the recombination of hemoglobin from isolated alpha- and beta-chains (human) was studied by following the change in small-angle scattering from a reaction mixture using synchrotron radiation. The scattering patterns were recorded successively within 51 s at intervals of 200 ms. The results suggest that when 2 mM solutions of CO-liganded alpha- and beta-chains are mixed in stoichiometric amounts at pH 7.

Mode of binding of cytochrome b5 to phospholipid bilayers in lamellar structure.

X-ray diffraction studies were made on the multilamellar systems produced by incubation of phospholipid bilayers and the membrane protein, cytochrome b5, or non-membrane proteins (albumin, ovalbumin and beta-lactoglobulin A) at pH 8.1 in aqueous 5 mM CaCl2 solutions. Detergent-extracted cytochrome b5 (soluble aggregate) forms two types of lamellar phase with dipalmitoyl phosphatidylcholine bilayers, depending upon the incubation temperature.

Effects of cations on dipalmitoyl phosphatidylcholine/cholesterol/water systems.

X-ray diffraction studies have been made on the effects of cations upon the dipalmitoyl phosphatidylcholine/water system, which originally consists of a lamellar phase with period of 64.5 A and of excess water. Addition of 1 mM CaCl2 destroys the lamellar structure and makes it swell into the excess water.