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At least 1,135 records · Page 63Linked to original sources
PubMed2004

Characterization of a fasciclin I-like protein with cell attachment activity from sea urchin (Strongylocentrotus intermedius) ovaries.

Fasciclin I, a neuronal cell adhesion molecule, was first identified in the grasshopper. To date, various fasciclin I-like proteins have been identified but their biological functions have not been well characterized. Here, we have purified a fasciclin I-like protein with a molecular weight of 33kDa from sea urchin (Strongylocentrotus intermedius) ovaries using hydrophobic chromatography and gel filtration. The protein was not N-glycosylated. Partial amino acid sequences of cyanogen bromide (CNBr)-cleaved fragments were highly conserved to other sea urchin fasciclin I-like proteins identified previously. The circular dichroism (CD) spectrum analysis demonstrated that the 33kDa protein contained high content of alpha-helical structure. These results suggest that the 33kDa protein is a fasciclin I-like family. Additionally, the fasciclin I-like protein promoted HT1080 human fibrosarcoma cell attachment. Further, a synthetic peptide (P1: GLREAANIAEQVDLRQVLRDVDL) of the protein corresponding to a highly conserved region of the fasciclin I-like family promoted heparin-dependent HT1080 cell attachment. Moreover, the peptide inhibited HT1080 cell attachment to the fasciclin I-like protein. These results suggest that the 33kDa protein from sea urchin ovaries isolated here is a member of the fasciclin I family and that the N-terminal region of the protein is important for cell attachment activity. The protein has a potential to be involved in biological functions in sea urchin as a cell adhesive molecule.

Amino Acid Sequence↗
PubMed2004

Autonomic cardiovascular changes during and after 14 days of head-down bed rest.

A 14-day, 6 degrees head-down bed rest (HDBR) study was conducted with 12 healthy young men to determine whether there are transient responses of the cardiovascular autonomic regulatory system including cardiovascular, autonomic nervous, and cardiac baroreceptor reflex functions in the acute phases of HDBR and post-HDBR. Compared with the supine position before bed rest, the high-frequency band power (HF(RRI)) of RR intervals (RRIs) decreased significantly at 3, 6, and 24 h of HDBR. This tendency went on until 24 h post-HDBR. Three kinds of cardiac baroreceptor reflex sensitivity (BRS) were estimated from closed-loop approaches to simultaneously recorded spontaneous RRI and systolic arterial pressure (SAP) fluctuations. BRSsequence is based on the simultaneous changes between RRI and SAP. alphaLF and alphaHF are based on a cross-spectrum analysis for low- and high-frequency bands of RRI and SAP. Although BRSsequence decreased significantly at acute phases of both HDBR and post-HDBR, neither alphaLF nor alphaHF decreased significantly at any of the acute phases of HDBR and post-HDBR. Our results suggest that HF(RRI) and BRSsequence can be used effectively to reveal reductions in cardiac vagal nervous modulation on the sinus node and cardiac BRS within 24 h of both HDBR and post-HDBR.

Adaptation, Physiological↗
PubMed2005

Biochemical characterization of recombinant phosphoglucose isomerase of Mycobacterium tuberculosis.

Phosphoglucose isomerase (PGI) is a well-characterized ubiquitous enzyme involved in the glycolytic pathway. It catalyzes the reversible isomerization of D-glucopyranose-6-phosphate and D-fructofuranose-6-phosphate and is present in all living cells. However, there is interspecies variation at the level of the primary structure which sometimes produces heterogeneity at the structural and functional levels. In order to evaluate and characterize the mycobacterial PGI, the gene encoding the PGI from Mycobacterium tuberculosis H37Rv was cloned in pET-22b(+) vector and expressed in Escherichia coli. The target DNA was PCR amplified from the bacterial artificial chromosome using specific primers and cloned under the control of T7 promoter. Upon induction with IPTG, the recombinant PGI (rPGI) expressed partly as soluble protein and partly as inclusion bodies. The rPGI from the soluble fraction was purified to near homogeneity by ion-exchange chromatography. Mass spectrum analysis of the purified rPGI revealed its mass to be 61.45 kDa. The purified rPGI was enzymatically active and the specific activity was 600 U/mg protein. The K(m) of rPGI was determined to be 0.318 mM for fructose-6-phosphate and the K(i) was 0.8 mM for 6-phosphogluconate. The rPGI exhibited optimal activity at 37 degrees C and pH 9.0, and did not require mono- or divalent cations for its activity.

Amino Acid Sequence↗
PubMed2004

Characterization of surface property of poly(lactide-co-glycolide) after oxygen plasma treatment.

In this study, poly (lactide-co-glycolide) (PLGA) films were treated by oxygen plasma. The surface structure, topography and surface chemistry of treated PLGA films were characterized by contact angle measurement, scanning electron microscope observation, atomic force microscopy, and X-ray photoelectron spectrum analysis. The cell affinity of the oxygen plasma treated films was evaluated under dynamic conditions by Parallel Plate Flow Chamber (PPFC). The results showed that the hydrophilicity increased greatly after oxygen plasma treatment. High quantities of -C-O groups, such as hydroxyl and peroxyl groups could be incorporated into the surface of PLGA (70/30) by controlling appropriate plasma treatment conditions. Moreover, the oxygen plasma treatment resulted in formation of peaks and valleys on the sample surfaces, and the roughness increased with treatment time. Cells stretched very well and the ability to endure the shear stress was improved greatly after the PLGA (70/30) was modified by appropriate plasma treatment, i.e. under 50W for 2 or 10 min. However, when the treatment time was increased to 20 min, the percentage of adherent cells on the roughest surface decreased because the content of polar groups incorporated onto the surface decreased. The results showed that improved cell adhesion was attributed to the combination of surface chemistry and surface morphology of PLGA during plasma etching.

Animals↗
PubMed2003

Blood pressure variability during 120-day head-down bed rest in humans.

Influence of physical inactivity and microgravity to periodic structure of blood pressure was studied. Six healthy males were kept under head-down bed rest (HDBR) for 120 days. Blood pressure and heart rate (HR) were recorded by a portable sphygmomanometer and a Holter electrocardiogram, respectively. The results were analyzed by spectrum analysis. Phase, amplitude and acrophase of systolic blood pressure (SBP) by approximately 24, 12 and 8 h were measured before, 60, 120 day and after HDBR. The phase at 24, 12 and 8 h did not show significant changes during HDBR, and acrophase showed a tendency to shift to 14:00 after HDBR. Amplitude for 24 h tended to attenuate during bed rest (BR), and significantly increased after BR. The results of this study suggest that the circadian rhythm of SBP and HR were maintained by strict control of sleep, awakening and food intake in microgravity model of a long-term BR state. However, the tendency to decrease 24-h cyclic amplitude of SBP appeared to be the rhythmic modulation related to cardiovascular deconditioning.

Adaptation, Physiological↗
PubMed2004

Inhibition of nociceptin/orphanin FQ on penicillin-induced seizures in rats.

The opioid peptides were thought to be involved in specific types of seizures. Nociceptin/Orphanin FQ (NC) is the endogenous ligand of the nociceptin opioid peptide (NOP) receptor and may play a role in epilepsy. However, accumulated evidences indicated that NC had both anti- and pro-convulsive effects, and the direct effect of NC in modulating epilepsy in the hippocampus still remained unclear. In this study, we investigated the effect of NC on penicillin-induced seizures (PIS) in rats. Seizure model was produced by intra-hippocampus injection of penicillin in anesthetized rats. The electroencephalography (EEG) was then observed and estimated by power spectrum analysis. Pretreatment of NC (intracerebroventricular, i.c.v.) depressed PIS in a dose-dependent manner at doses of 0.055, 0.55 and 5.5 nmol in 2 microl saline, respectively. [Nphe1]Nociceptin(1-13)NH2, a selective NOP receptor antagonist reversed the effect of NC against PIS, and this antagonist was inactive to PIS itself. These results indicated that NC had a receptor-specific preventive effect against PIS.

Animals↗
PubMed2004

Comparison of azo dye degradation efficiency using UV/single semiconductor and UV/coupled semiconductor systems.

This study examined degradation of azo dyes using photocatalytic oxidation (UV/semiconductor). The model substrates employed in this work were Procion Red MX-5B and Amaranth, while the photocatalysts were TiO2, ZnO, and SnO2. UV-Vis spectrum analysis demonstrated that the band gap energies of TiO2, ZnO, and SnO2 were 3.17, 2.92, and 4.13 eV, respectively. The band gap energy of SnO2 is insufficient to initiate photocatalytic reaction after UV irradiation (365 nm). The reaction rate constants fit a first-order reaction model and the reaction rate constant of Procion Red MX-5B for TiO2+SnO2 (0.31 h-1) is larger than that of TiO2 (0.24 h-1) and SnO2 at pH 10. The difference between the conduction bands of SnO2 and TiO2 enables the former to act as a sink for the photogenerated electrons. Most of the reaction rate constants had higher values at pH 10 than pH 7, and thus the OH attack could be assumed to represent the main reaction in this investigation. The quantities of sulfate and chloride ions released are below stoichiometry during the degradation. Owing to the sulfonate groups of Amaranth exceeding Procion Red MX-5B, Amaranth had larger electrostatic attraction than Procion Red MX-5B with the surface of ZnO, and also had higher adsorption percentage than Procion Red MX-5B on the surface of ZnO. The trend of adsorption is consistent with the reaction rate constant at pH 7, namely Amaranth>Procion Red MX-5B. The sulfate dissociation rate constant of Amaranth in UV/ZnO at pH 7 (0.49 h-1) approaches the overall rate constant (0.53 h-1); therefore, the first step involved in Amaranth can be suggested to the cleavage of the bonds of the C-S in Amaranth, causing sulfate ion formation.

Azo Compounds↗
PubMed2004

Altered central nervous system signal during motor performance in chronic fatigue syndrome.

OBJECTIVE: The purpose of this study was to determine whether brain activity of chronic fatigue syndrome (CFS) patients during voluntary motor actions differs from that of healthy individuals. METHODS: Eight CFS patients and 8 age- and gender-matched healthy volunteers performed isometric handgrip contractions at 50% maximal voluntary contraction level. They first performed 50 contractions with a 10 s rest between adjacent trials--'Non-Fatigue' (NFT) task. Subsequently, the same number of contractions was performed with only a 5 s rest between trials--'Fatigue' (FT) task. Fifty-eight channels of surface EEG were recorded simultaneously from the scalp. Spectrum analysis was performed to estimate power of EEG frequency in different tasks. Motor activity-related cortical potential (MRCP) was derived by triggered averaging of EEG signals associated with the muscle contractions. RESULTS: Major findings include: (i) Motor performance of the CFS patients was poorer than the controls. (ii) Relative power of EEG theta frequency band (4-8 Hz) during performing the NFT and FT tasks was significantly greater in the CFS than control group (P < 0.05). (iii) The amplitude of MRCP negative potential (NP) for the combined NFT and FT tasks was higher in the CFS than control group (P < 0.05) (iv) Within the CFS group, the NP was greater for the FT than NFT task (P<0.01), whereas no such difference between the two tasks was found in the control group. CONCLUSIONS: These results clearly show that CFS involves altered central nervous system signals in controlling voluntary muscle activities, especially when the activities induce fatigue. SIGNIFICANCE: Physical activity-induced EEG signal changes may serve as physiological markers for more objective diagnosis of CFS.

Adult↗
PubMed2005

Infraslow EEG activity in burst periods from post asphyctic full term neonates.

OBJECTIVE: To investigate whether very low EEG frequency activity can be recorded from post asphyctic full term neonates using EEG equipment where the high pass filter level was lowered to 0.05 Hz. METHODS: The time constant of the amplifier hardware was set to 3.2 s in order to enable recordings that equal to a high pass filter cut off at 0.05 Hz. Burst episodes were selected from the EEGs of 5 post asphyctic full term neonates. The episodes were analysed visually using different montages and subjected to power spectrum analysis. Powers in two bands were estimated; 0-1 and 1-4 Hz, designated very low- and low-frequency activity, respectively (VLFA, LFA). RESULTS: In all infants, VLFA coinciding with the burst episodes could be detected. The duration of the VLFA was about the same as that of the burst episode i.e. around 4s. The activity was most prominent over the posterior regions. In this small material, a large amount of VLFA neonatally seemed to possibly be related to a more favourable prognosis. CONCLUSIONS: VLFA can be recorded from post asphyctic full term neonates using EEG equipment with lowered cut off frequency for the high pass filter. SIGNIFICANCE: VLFA normally disregarded due to filtering, is present in the EEG of sick neonates and may carry important clinical information.

Action Potentials↗
PubMed2005

Short term heart rate variability in healthy neonates: normative data and physiological observations.

BACKGROUND: The measurement of heart rate variability (HRV) reveals information on the functional state of the autonomic nervous system (ANS). Moreover, several diseases are known to be accompanied by a reduction in HRV. Currently, there are no data on HRV within larger samples of healthy neonates. AIM: This study was initiated to establish normative data of HRV parameters and to assess physiological observations in healthy newborn infants. STUDY DESIGN: We performed 10 min recordings of HRV in 80 healthy neonates. We computed time domain parameters. Furthermore power spectrum analysis was calculated by Fourier Transformation in 3 frequency bands. The total power as well as the peak frequencies was estimated for each band. RESULTS: The normative data of each HRV parameter for healthy newborns are presented as mean, standard deviation and the 5th and 95th percentiles. Increasing postnatal age is accompanied by a significant (p<0.05) elevation of HRV parameters. Baroreceptor loop fluctuations were delayed from 0.1 Hz (adults) to 0.07 Hz in healthy newborns. A respiratory peak according to respiratory sinus arrhythmia (RSA) as it is common in adults was not detectable. CONCLUSIONS: Normative data of HRV allows the interpretation of clinical data in neonatal diseases affecting the ANS. Moreover, we observed physiological deviations in healthy newborns in comparison to adults.

Autonomic Nervous System↗
PubMed2005

Heart rate variability: from bench to bedside.

Power spectrum analysis of cardiovascular signal variability, and in particular of the RR period (heart rate variability, HRV), is a widely used methodology for investigating autonomic neural regulation in health and disease that can quantify the sympathovagal balance modulating the sinus node pacemaker. In some cases, it can also quantify the neural regulation of other organs or apparatuses. However, use of the correct methodology is crucial to extract the information embedded in the frequency domain. In numerous abnormal conditions, such as essential arterial hypertension, acute myocardial infarction and heart failure, the sympathovagal balance may be altered in basal conditions. However, a reduced responsiveness to an excitatory stimulus is the most common feature that characterizes numerous pathophysiological states. The attenuation of an oscillatory pattern can also reflect an altered target function, thus providing important prognostic markers. The general features of this approach correspond well to the needs of an internist attempting to envisage the involvement of the whole organism in a disease process.

Journal Article↗
PubMed2004

Effects of second-generation histamine H1 receptor antagonists on the sleep-wakefulness cycle in rats.

The present study was performed to examine the sedative effects of second-generation histamine H(1) receptor antagonist using power spectrum analysis in the rat. Similar to ketotifen, olopatadine caused a decrease in sleep latency at a dose of 50 mg/kg, while epinastine and cetirizine showed no significant effect even at a dose of 50 mg/kg. On the other hand, no significant difference was observed in the total times of wakefulness, non-rapid eye movement sleep and rapid eye movement sleep by any drugs used in the experiments. The number of sleep phases and interval between sleep phases were also unchanged by these drugs. Ketotifen and olopatadine inhibited [(3)H]mepyramine binding to rat brain homogenates in parallel with a decrease in sleep latency. No significant effect was observed with epinastine and cetirizine on [(3)H]mepyramine binding. These findings suggest that the differences in the central nervous system (CNS) depressant effect observed in second generation H(1) receptor antagonists may be due to their liability to penetrate into the CNS.

Animals↗
PubMed2004

In-line monitoring of a pharmaceutical blending process using FT-Raman spectroscopy.

FT-Raman spectroscopy (in combination with a fibre optic probe) was evaluated as an in-line tool to monitor a blending process of diltiazem hydrochloride pellets and paraffinic wax beads. The mean square of differences (MSD) between two consecutive spectra was used to identify the time required to obtain a homogeneous mixture. A traditional end-sampling thief probe was used to collect samples, followed by HPLC analysis to verify the Raman data. Large variations were seen in the FT-Raman spectra logged during the initial minutes of the blending process using a binary mixture (ratio: 50/50, w/w) of diltiazem pellets and paraffinic wax beads (particle size: 800-1200 microm). The MSD-profiles showed that a homogeneous mixture was obtained after about 15 min blending. HPLC analysis confirmed these observations. The Raman data showed that the mixing kinetics depended on the particle size of the material and on the mixing speed. The results of this study proved that FT-Raman spectroscopy can be successfully implemented as an in-line monitoring tool for blending processes.

Fourier Analysis↗
PubMed2004

Effects of sweet and bitter gustatory stimuli in anorexia nervosa on EEG frequency spectra.

The possible differences in processing gustatory stimuli in anorexic patients compared to healthy control subjects was investigated by electrophysiological methods. The electroencephalogram (EEG) was recorded in outpatients treated with anorexia nervosa (AN) and age-matched controls after exposure to sweet (milk chocolate) and bitter (black tea) taste stimuli. Power spectrum analysis was performed on EEG epochs recorded in the above conditions. Compared to controls a significantly higher percent of theta, and lower percent of alpha1 band power was found in anorexic patients, irrespective of the kind of taste effects and hemispheric side. The pattern of activation caused by sweet and bitter stimuli was found to be different in these two groups, possibly indicating altered gustatory processing mechanisms in AN.

Adolescent↗
PubMed2006

Trihalomethanes formation potential of shrimp farm effluents.

Shrimp farm effluents along the Bangpakong River in the Chachoengsao Province of Thailand were evaluated for their trihalomethane formation potential (THMFP) and related parameters. The dissolved organic carbon (DOC), salinity and bromide ion concentrations of shrimp farm effluents were in the ranges of 12-14 mg/L, 0.1-14.5 ppt, and 0-14 mg/L, respectively. The dissolved organic matter was fractionated into hydrophobic and hydrophilic fractions having a range concentration of 3-5 and 8-10mg/L, respectively. The THMFP for all shrimp farm effluents analyzed was in the range of 810-3100 microg/L. The hydrophilic organic fraction was found to be a more active precursor of trihalomethanes (THMs) with 700-966 microg/L THMFP obtained from this fraction, while only 111-363 microg/L THMFP was derived from the hydrophobic fraction. The experimental results showed that salinity and bromide played crucial roles in the formation of THMs. At low salinity and bromide levels, chloroform was the dominant THM species, whereas at high salinity and bromide levels, bromoform became the dominant species. A Fourier Transform Infrared (FTIR) spectrum analysis of the samples before and after chlorination illustrated that the functional groups involved in the THM formation reaction were phenolic compounds, amines, aromatic hydrocarbons, aliphatic bromo-compounds, and aliphatic chloro-compounds.

Animals↗
PubMed2006

Sorption and desorption of lead (II) from wastewater by green algae Cladophora fascicularis.

Biosorption is an effective method to remove heavy metals from wastewater. In this work, adsorption features of Cladophora fascicularis were investigated as a function of time, initial pH, initial Pb(II) concentrations, temperature and co-existing ions. Kinetics and equilibria were obtained from batch experiments. The biosorption kinetics followed the pseudo-second order model. Adsorption equilibria were well described by the Langmuir and Freundlich isotherm models. The maximum adsorption capacity was 198.5 mg/g at 298K and pH 5.0. The adsorption processes were endothermic and the biosorption heat was 29.6 kJ/mol. Desorption experiments indicated that 0.01 mol/L Na(2)EDTA was an efficient desorbent for the recovery of Pb(II) from biomass. IR spectrum analysis suggested amido or hydroxy, CO and C-O could combine intensively with Pb(II).

Adsorption↗
PubMed2004

Increased frontal white matter diffusion is associated with glial metabolites and psychomotor slowing in HIV.

Diffusion-weighted imaging (DWI) measures brain water diffusion that is sensitive to microscopic brain injury. A total of 11 HIV seropositive patients were compared to 14 seronegative subjects using DWI, proton magnetic resonance spectroscopy (1H MRS), and neuropsychological tests. The apparent diffusion coefficient (ADC) was significantly increased in the HIV patients, primarily in the frontal white matter (FWM; +5%, p=0.01). Diffusivity correlated positively with the glial marker myo-inositol (r=0.5, p=0.008) and negatively with cognitive performance (NPZ-8 composite score; r=-0.43, p=0.05). These findings suggest increased brain water diffusion may reflect increased glial activation or inflammation, which in turn, may contribute to the cognitive deficits in HIV patients.

Adolescent↗
PubMed2005

Nondestructive determination of the ambroxol content in tablets by Raman spectroscopy.

We describe a method for determining the ambroxol content in tablets nondestructively. To obtain a reliable quantitative calibration, we prepared 20 pellet samples (ambroxol content: 8.30-16.25 wt.%) and acquired their Raman spectra while rotating the pellets. The spectra of the rotated samples reflected the compositional variations better than those that were recorded without rotation. To reduce both the baseline variations and the spectral noise simultaneously, the spectra were pre-processed using wavelet transformation (WT). Then, we used the normalization method before partial least-squares (PLS) regression to correct Raman intensity variation from laser power fluctuation. The achieved standard error of cross validation (SECV) was 0.30%. Two different datasets where Raman intensity was artificially changed were prepared and the corresponding spectra were quantitatively analyzed. The result was reproducible even if laser intensity was fairly changed. Additionally, two different commercial tablets were analyzed and the accuracy of measurement was better for a tablet that had the similar spectral features of the standard pellet samples. The proposed method can be utilized for the analysis of commercial tablets if standard tablets of various ambroxol concentrations that have the same chemical components including additives and the same physical shape of tablets are available.

Ambroxol↗