Bending modulus of lipid bilayers in a liquid-crystalline phase including an anomalous swelling regime estimated by neutron spin echo experiments

Membrane fluctuations of dipalmitoylphosphatidylcholine (DPPC) and dimyristoylphosphatidylcholine (DMPC) were investigated by neutron spin echo spectroscopy. The intermediate structure factor was analyzed in terms of the model proposed by Zilman and Granek (Phys. Rev. Lett. 77, 4788 (1996)), and the bending modulus of lipid bilayers was derived. The hardening of a lipid bilayer upon approaching the main transition point in the anomalous swelling regime was observed, which naturally connects the bending modulus in the gel phase below the main transition temperature.

Blebbing dynamics in an oil-water-surfactant system through the generation and destruction of a gel-like structure

Interfacial dynamical blebbing of an oil droplet on an aqueous solution is reported. The oil droplet and the aqueous solution contain a fatty acid and a cationic surfactant, respectively. When the oil droplet was placed on an aqueous surface, the oil-water interface formed blebs, spherical extrusions on the oil-water interface and circular ones on the edge of the oil droplet. With increase of the concentration of the surfactant and/or the fatty acid, the generated blebs become smaller. Based on the experimental observations together with theoretical considerations, we conclude that the bleb formation is induced through generation and destruction of a gel-like intermediate phase.

Triterpenoids from Cimicifugae rhizoma, a novel class of inhibitors on bone resorption and ovariectomy-induced bone loss

OBJECTIVE

Increasing research suggested that Cimicifugae rhizoma might be protective against osteoporosis. In this study, we investigated the effects of three cycloartane-type triterpenoids isolated from Cimicifugae rhizoma, cimicidol-3-O-beta-D-xyloside (1), cimicidanol-3-O-beta-D-xyloside (2) and acetylacteol-3-O-beta-d-xyloside (3) on bone resorption in vitro and bone loss in ovariectomized (OVX) mice.

METHODS

The activities of the tested compounds on bone resorption were evaluated using three assays, neonatal mouse parietal bone organ culture, osteoclast-like cells (OCLs) formation and pit formation. The effects on bone mineral density (BMD) and uterine weight were examined using OVX mice. Using LC-MS/MS method, the serum concentrations of the triterpenoids were measured in mice serum collected at 0.5, 1, 3, 6 and 12h following its oral administration.

RESULTS

All of the tested compounds exerted the inhibitory effects on bone resorption in bone organ culture, suppressed both of the formation and the resorbing activity of OCLs. Furthermore, a synergistic effect was observed among those compounds. In vivo studies revealed that compounds 1-3 and the mixture of compounds 1-3 prevented the bone loss in OVX mice without affecting uterine weight, and each compound was detected in the mice serum after single oral administration.

CONCLUSIONS

The triterpenoids exerted the inhibitory effects on osteoclastic bone resorption through the suppression of both OCLs formation and the resorbing activity of OCLs, and also showed a significant protective effect on BMD in OVX mice. The present results might provide a new pharmacological potential for the treatment of osteoporosis.

Pressure effects on bending elasticities of surfactant monolayers in a ternary microemulsion composed of aerosol-OT∕D2O/decane

Pressure effects on the bending elasticities of surfactant monolayers have been investigated in a microemulsion system composed of aerosol-OT (AOT), D2O, and deuterated decane by means of small angle neutron scattering, neutron spin echo (NSE), and dynamic light scattering (DLS). In this system, a water-in-oil droplet structure, at ambient temperature and pressure, decomposes into two phases, under both increasing temperature and pressure. The authors' previous study showed that the bending modulus kappa of monolayers slightly decreased with increasing temperature, while it increased with increasing pressure. Temperature and pressure dependencies of kappa were explained in terms of a microscopic model, which takes into account the interactions between surfactant molecules. In this paper, the authors present the temperature and pressure dependencies of kappa obtained by the analysis combined with DLS and NSE experiments. The values of the bending modulus and mean displacement of the second-order droplet deformation are reasonable. It was further confirmed that an increase in the attractive interaction between hydrocarbon tails of AOT molecules with increasing pressure could be the origin of the pressure-induced phase transition.

Interaction between droplets in a ternary microemulsion evaluated by the relative form factor method

This paper describes the concentration dependence of the interaction between water droplets coated by a surfactant monolayer using the contrast variation small-angle neutron scattering technique. In the first part, we explain the idea of how to extract a relatively model free structure factor from the scattering data, which is called the relative form factor method. In the second part, the experimental results for the shape of the droplets (form factor) are described. In the third part the relatively model free structure factor is shown, and finally the concentration dependence of the interaction potential between droplets is discussed. The result indicates the validity of the relative form factor method, and the importance of the estimation of the model free structure factor to discuss the nature of structure formation in microemulsion systems.

Milk basic protein increases alveolar bone formation in rat experimental periodontitis

BACKGROUND AND OBJECTIVE

It is conceivable that the active components extracted from milk whey protein (i.e. milk basic protein, MBP) stimulate bone formation and suppress bone resorption. Periodontitis is characterized by excessive alveolar bone resorption. We examined whether milk basic protein could recover alveolar bone loss in rat experimental periodontitis.

MATERIAL AND METHODS

A nylon ligature was placed around the cervix of molars in 8-wk-old male Fischer rats for 20 d. Then, the ligature was removed and a powder diet containing 0.2 or 1.0% milk basic protein was provided daily for another 45-90 d. On days 45 and 90, the maxillae were extracted and analyzed using microcomputerized tomography (micro-CT), followed by histological analysis.

RESULTS

Micro-CT images showed that alveolar bone resorption was severely induced around the molar by the 20-d ligature procedure. Treatment with high-dose milk basic protein (1.0%) clearly recovered ligature-induced alveolar bone resorption on days 45 and 90, whereas low-dose milk basic protein (0.2%) did not show such a clear effect. Histological examination clarified that the osteoid thickness of alveolar bone was dose dependently increased by milk basic protein treatment for 90 d.

CONCLUSION

These findings suggest that a systemic administration of milk basic protein may be effective for the recovery of alveolar bone loss in periodontitis.

Indoor organophosphate and polybrominated flame retardants in Tokyo

In Japan, organophosphate and polybrominated flame retardants are used in building materials and electric appliances to protect them from fire hazards. In this study, to identify the emission sources of these flame retardants to indoor air, the migration rates (flux) of organophosphate and polybrominated flame retardants from building materials and electrical appliances to solid extraction disks that were placed in contact with the interior surfaces were measured. In addition to the migration test, indoor air and outdoor air concentrations of these flame retardants were investigated. With regard to building materials in a newly built house, triethylphosphate (TEP) and tributylphosphate (TBP) were detected in the wall and ceiling coverings, and tris(2-butoxyethyl)phosphate (TBEP) was detected in the wooden flooring cleaned with a floor polish agent. With regard to electrical appliances, triphenylphosphate (TPHP) was predominantly detected in computer monitors and tris(2-chloroethyl) phosphate (TCEP) in television (TV) sets, with the highest median levels. Among the polybrominated compounds, only 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) was detected from a few old TV sets manufactured before 1995. In an indoor and outdoor air survey, nine organophosphates and nine polybrominated flame retardants were detected from indoor air. In outdoor air, only four organophosphate flame retardants were detected. The maximum level of indoor organophosphate compounds was 1260 ng/m(3) with tris(2-chloro-1-methylethyl) phosphate (TCPP), and that of polybrominated compounds was 29.5 ng/m(3) with hexabromocyclododecane (HBCD). Tetrabromobisphenol A (TBBPA) was not detected in this study, although it has the largest demand among flame retardants in Japan. The results of the migration test and the indoor air survey revealed that in indoor air, organophosphate compounds were more predominant than polybrominated compounds in Tokyo.

PRACTICAL IMPLICATIONS

Polybrominated biphenyls (PBB) and polybrominated diphenyl ethers (PBDE) are commonly used as flame retardants in plastics. The use of these two compounds in electric appliances will be banned in 2007 by the EU Directives on waste electrical and electronic equipment (WEEE) and on the restriction of the use of certain hazardous substances (RoHS) in electrical and electronic equipment. In Japan, the use of PBB was banned and that of PBDE diminished in the early 1990s by the self-imposed controls of the Japanese Flame Retardants Conference (Akutu and Hori, 2004). In Japan, the predominantly used organic flame retardants were tetrabromobisphenol A and organophosphate compounds. Tetrabromobisphenol A has been reported to disrupt endocrine systems (Kitamura et al., 2005), and some organophosphate flame retardants were recently reported to have neurochemical hazardous effects. Furthermore, organophosphate compounds were suspected to cause endocrine-disrupting effects (Fang et al., 2003; Ohyama et al., 2005) or attention deficit hyperactivity disorder (ADHD) (Winrow et al., 2003). In this study, organophosphate and polybrominated flame retardants were surveyed in indoor environments in Tokyo.

Intracranial dural arteriovenous fistulas with retrograde cortical venous drainage: assessment with cerebral blood volume by dynamic susceptibility contrast magnetic resonance imaging

BACKGROUND AND PURPOSE

Retrograde cortical venous drainage (RCVD) is the most major risk factor for aggressive behavior of intracranial dural arteriovenous fistulas (DAVF). The purpose of this study was to assess the efficacy of relative cerebral blood volume (rCBV) map for RCVD in patients with DAVF.

METHODS

Ten patients with angiographically proven DAVF with RCVD, 2 reference patients with DAVF without RCVD, and 10 control subjects underwent examinations with dynamic susceptibility contrast (DSC)-MR imaging. Four patients with DAVF with unilateral RCVD were evaluated, before and after treatment. The calculation of mean rCBV ratio was performed on a hemispheric basis. The mean rCBV ratio was defined as the value on one side (higher value side) divided by that on the other side (lower value side).

RESULTS

In all patients with DAVF with RCVD, the rCBV map showed an increase in rCBV of the angiographically proved affected hemisphere. In 2 reference patients with DAVF without RCVD and all control subjects, the rCBV map showed no increase of rCBV. The mean rCBV ratio in patients with DAVF with RCVD was significantly higher than that of control subjects (P = .0002). Treatment response for RCVD was indicated by a decrease of CBV on the rCBV map and by a decrease of 22% in the mean rCBV ratio.

CONCLUSIONS

Increased rCBV by DSC-MR correlated with RCVD in patients with DVAF. The assessment with rCBV for RCVD may be more quantitative than that with angiogram.

Pressure-induced hexagonal phase in a ternary microemulsion system composed of a nonionic surfactant, water, and oil

The pressure-induced phase transition in a microemulsion, consisting of pentaethylene glycol mono-n-dodecyl ether, water, and n-octane, was investigated by means of small-angle neutron scattering. A pressure-induced phase transition from a lamellar structure to a hexagonal structure was observed. The temperature-pressure phase boundary shows a positive slope with dTdP approximately 0.09 KMPa. The structure unit of the high-pressure hexagonal phase was an oil-in-water cylinder with the membrane thickness of 15.5 A, identical to the low-temperature hexagonal phase. Pressurizing was found to have the same effect by decreasing temperature. This behavior was satisfactorily explained with the pressure dependence of the spontaneous curvature of surfactant membranes. That is, the volume change of surfactant tails plays a dominant role in the structure change of the microemulsion with applying pressure.

Morphological brain changes associated with Schneider's first-rank symptoms in schizophrenia: a MRI study

BACKGROUND

Schneider's first-rank symptoms involve an alienated feature of the sense of one's own mental or physical activity. To clarify the brain morphological basis for the production of these symptoms, volumes of the frontal and medial temporal regions and their clinical correlates were examined in patients with schizophrenia.

METHOD

Twenty-two patients with schizophrenia and 44 age- and gender-matched healthy control subjects were included. All patients were in their psychotic episodes with definite Schneiderian symptoms, rated by using the Scale for Assessment of Positive Symptoms. Volumetric measurements of high-resolution magnetic resonance imaging were performed in the prefrontal area, cingulate gyrus, and precentral gyrus, and the medial temporal structures such as the amygdala, hippocampus, and parahippocampal gyrus.

RESULTS

Patients had significantly decreased volumes in the cingulate gray matter and the amygdala compared to controls. In the patient group, Schneiderian symptom severity showed significant inverse correlations with volumes of the right posterior cingulate gray matter and of the left anterior parahippocampal gyrus.

CONCLUSIONS

Schneiderian symptoms may be associated with morphological abnormalities in the limbic-paralimbic regions such as the cingulate gyrus and parahippocampal gyrus, which possibly serve the self-monitoring function and the coherent storage and reactivation of information.

Neutron spin-echo studies on dynamic and static fluctuations in two types of poly(vinyl alcohol) gels

We report neutron spin-echo measurements on two types of poly(vinyl alcohol) (PVA) gels. The first is PVA gel in a mixture of dimethyl sulfoxide (DMSO) and water with volume ratio 60/40 , and the second is PVA gel in an aqueous borax solution. The observed normalized intermediate scattering functions I (Q,t) /I (Q,0) are very different between them. The former I (Q,t) /I (Q,0) shows a nondecaying component in addition to a fast decay, but the latter does not have the nondecaying one. This clearly indicates that the fluctuations in the former PVA gel consist of static and dynamic fluctuations whereas the latter PVA gel does include only the dynamic fluctuations. The dynamic fluctuations of the former and latter gels have been analyzed in terms of a restricted motion in the network and Zimm motion, respectively, and the origins of these motions will be discussed.

Indoor air pollution by alkylphenols in Tokyo

The purposes of this study were to develop an analytical method for airborne alkylphenols (APs) using the gas chromatography/mass spectrometry (GC/MS)-SIM method and to investigate airborne C4-C9 APs pollution in houses, offices, and outdoor points in Tokyo. In addition, to identify APs emission sources in a newly built house, migration tests of APs from interior surfaces to solid extraction disks were performed. Air samples were collected from houses, offices, and outdoor points. The recovery of APs from air samples was increased by addition of ascorbic acid to the filters. 4-tert-butylphenol (4-t-BP), 4-tert-octylphenol (4-t-OP), and 4-nonylphenol (4-NP) were detected in both indoor and outdoor air. Their concentrations and detection frequencies were higher in indoor air than outdoor air. The maximum levels of 4-t-BP, 4-t-OP, and 4-NP in indoor were 387, 45.7, and 680 ng/m(3), respectively. 4-t-BP and 4-NP were detected with high frequencies (more than 97%) in indoor air samples. The concentrations of 4-t-BP, 4-t-OP, and 4-NP in indoor air were significantly correlated with room temperature (P < 0.01), and tended to be higher in newly built houses. The migration rates of APs from the floor, wall, and ceiling in the newly built house were higher in polyvinyl chloride coverings than in other materials. Practical Implications Alkylphenol ethoxylate (APE) are widely used surfactants in both industrial and domestic detergents. When these detergents are released into the environment, APE are biodegraded to the smaller chain ethoxylates and alkylphenols (APs). There are many reports about APs in aquatic environments because of their estrogenic effect on wildlife. In building materials, APs are used as antioxidant for polymer resins such as wall or floor coverings. Although APs has a lower vapor pressure, these agents are released into indoor air from the surface of polymer resins. This study surveyed concentrations of airborne AP in indoor air and outdoor air in Tokyo. In addition, to identify APs emission sources in a newly built house, migration tests of APs from interior surfaces to solid extraction disks were performed.

PRACTICAL IMPLICATIONS

Alkylphenol ethoxylate (APE) are widely used surfactants in both industrial and domestic detergents. When these detergents are released into the environment, APE are biodegraded to the smaller chain ethoxylates and alkylphenols (APs). There are many reports about APs in aquatic environments because of their estrogenic effect on wildlife. In building materials, APs are used as antioxidant for polymer resins such as wall or floor coverings. Although APs has a lower vapor pressure, these agents are released into indoor air from the surface of polymer resins. This study surveyed concentrations of airborne AP in indoor air and outdoor air in Tokyo. In addition, to identify APs emission sources in a newly built house, migration tests of APs from interior surfaces to solid extraction disks were performed.

Temperature and pressure effects on the bending modulus of monolayers in a ternary microemulsion

We performed small-angle neutron scattering and neutron spin echo experiments on a ternary microemulsion composed of ionic surfactant AOT, water, and decane. Thermal fluctuations of monolayers have been investigated as a function of temperature and pressure. The amphiphilic monolayers become more flexible with increasing temperature and more rigid with increasing pressure. These results are consistent with the microscopic picture that the head-head repulsion of the AOT molecules is enhanced at high temperature while an attractive interaction between the hydrophobic tails of the AOT molecules increases at high pressure.

Gray matter features of schizotypal disorder patients exhibiting the schizophrenia-related code types of the Minnesota Multiphasic Personality Inventory

OBJECTIVE

Previous studies have suggested that several code types of the Minnesota Multiphasic Personality Inventory (MMPI) are useful markers for identifying schizophrenia. We hypothesized that schizotypal disorder (STD) patients with such schizophrenia-related code types have the morphological brain abnormalities associated with schizophrenia.

METHOD

Voxel-based morphometric analysis with statistical parametric mapping (SPM) 99 software was used to investigate the differences in brain morphology between 14 STD patients with the schizophrenia-related code types of the MMPI and 28 normal individuals.

RESULTS

The STD patients showed significantly decreased gray matter volume in the insular regions bilaterally and in the left entorhinal cortex, compared with the controls.

CONCLUSION

Our findings suggest that STD patients with the schizophrenia-related code types have volume reductions in these regions as an endophenotype that overlaps with schizophrenia.

Serial diffusion-weighted imaging in a patient with MELAS and presumed cytotoxic oedema

A patient with mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS) was studied with serial diffusion-weighted MRI (DWI) after stroke-like episodes and the apparent diffusion coefficient (ADC) was measured in an infarct-like lesion. In the acute and subacute stages, the affected area gave high signal on DWI and its ADC was much lower than that in a normal control region. In the chronic stage, the ADC became higher than that in normal brain. We therefore suggest that the stroke-like episodes did not cause vasogenic oedema but were related to energy failure and cytotoxic oedema.