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PubMed1993

Sideband analysis in DOR NMR spectra. II. Real finite inner-rotor speed.

DOR (double orientation rotation) solid-state NMR technique is analyzed specifically in the case where numerous (> 4) sidebands are observed on the spectrum. In this case, a rough spectrum analysis leads to the false observation of several impurity species. The total "visible" intensity is smaller than the real one. This may lead to an apparent relative concentration change when several species with very different quadrupole interactions coexist in the sample. Contrary to the MAS technique, the correct analysis of DOR spectra with sidebands very often necessitates the simultaneous introduction of CSA and quadrupole interactions.

Anisotropy↗

PubMed2003

Analysis of HPRT and supF mutations caused by pierisin-1, a guanine specific ADP-ribosylating toxin derived from the cabbage butterfly.

Pierisin-1, an ADP-ribosylating toxin derived from the cabbage butterfly, Pieris rapae, induces apoptosis in various mammalian cell lines. We recently reported that the target for ADP ribosylation by pierisin-1 is the 2'-deoxyguanosine residue in DNA. To examine whether pierisin-1 would induce mutations in mammalian cell genes, we conducted a mutational analysis for the hypoxanthine-guanine phosphoribosyltransferase (HPRT) locus in pierisin-1-treated Chinese hamster lung (CHL) cells. N(2)-(ADP-ribos-1-yl)-2'-deoxyguanosine was detected by the (32)P-postlabeling method in CHL cells after treatment with pierisin-1 at doses of 2-32 ng/mL; adduct levels were 1.1-12.0 per 10(6) nucleotides. Pierisin-1 induced mutations in the HPRT gene dose-dependently, and the frequency was 38 times higher than the control, at a dose of 32 ng/mL. To confirm that mono(ADP-ribosyl)ated dG itself leads to mutations, the pierisin-1-treated DNA of plasmid pMY189 bearing the supF gene was used for mutational analysis. The mutation frequency of the supF gene treated with 2-8 micro g/mL of pierisin-1 was 17-40-fold the control value. Mutation spectrum analysis showed that single base substitutions dominated in both HPRT and supF genes. Among these, transversions were predominant, and more than 70% of the base substitutions occurred at G:C base pairs in both genes. The most frequent mutations were G:C to C:G, followed by G:C to T:A in HPRT gene, whereas G:C to T:A transversions dominated in the supF gene. Our results indicate that pierisin-1 produced N(2)-(ADP-ribos-1-yl)-2'-deoxyguanosine and this guanine-adduct could lead to mutations in the HPRT and supF genes. These findings could provide very useful information for understanding the biological significance of pierisin-1.

ADP Ribose Transferases↗

PubMed1986

Some correlations in geriatric patients between EEG parameters and clinical status as evaluated using the observer-rated SCAG rating scale. A retrospective study.

In a retrospective analysis, correlations were sought between pretreatment electroencephalographic and clinical data obtained in 18 therapeutic studies conducted in elderly patients according to almost identical protocols. Power spectrum analysis was applied to the EEG tracings, while clinical status was observer-rated using the Sandoz clinical assessment - geriatric (SCAG) scale. The study population comprised a total of 286 patients between the ages of 51 and 97 years (median age 70 years), 162 of whom were male (median age 68 years) and 124 female (median age 73 years). A 2-week washout period and several 'adaptation recordings' preceded the pretreatment EEGs used in this analysis. These tracings were recorded under resting conditions between 8 and 10 a.m. and were followed by an assessment of clinical status. Spearman rank correlations with 4 EEG parameters--total slow waves, alpha and beta waves, and dominant alpha frequency--were computed for all 18 SCAG items and for 'overall impression of patient' as well as for 5 SCAG factors. All 96 - (19 + 5) X 4 - correlation coefficients were formally tested for statistical significance at the nominal level of alpha = 0.05. In this analysis, 9 of the 18 items, 'overall impression' and two of the factors ('apathy' and 'somatic dysfunction') showed nominally significant correlations with at least 1 of the 4 EEG variables. As expected, a positive correlation was found between percentage slow-wave activity and degree of clinical impairment. In addition correlations were identified between clinical data and alpha and beta activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1996

Autonomic activity assessed by heart rate spectral analysis varies with fat distribution in obese women.

Obesity in humans has been associated with altered autonomic nervous system activity. The objective of this study was to examine the relationship between autonomic function and body fat distribution in 16 obese, postmenopausal women using power spectrum analysis of heart rate variability. Using this technique, a low frequency peak (0.04-0.12 Hz) reflecting mixed sympathetic and parasympathetic activity, and a high frequency peak (0.22-0.28 Hz) reflecting parasympathetic activity, were identified from 5-minute consecutive heart rate data (both supine and standing). Autonomic activity in upper body (UBO) vs. lower body obesity (LBO)(by waist-to-hip ratio) and subcutaneous vs. visceral obesity (by CT scan) was evaluated. Power spectrum data were log transformed to normalize the data. The results showed that standing, low-frequency power (reflecting sympathetic activity) and supine, high-frequency power (reflecting parasympathetic activity) were significantly greater in UBO than in LBO, and in visceral compared to subcutaneous obesity. Women with combined UBO and visceral obesity had significantly higher cardiac sympathetic and parasympathetic activity than any other subgroup. We conclude that cardiac autonomic function as assessed by heart rate spectral analysis varies in women depending on their regional body fat distribution.

Adipose Tissue↗

PubMed2006

Proteome analysis of cellular response of Pseudomonas putida KT2440 to tetracycline stress.

Tetracycline-induced proteome of Pseudomonas putida KT2440 was analyzed by 2-D gel electrophoresis and matrix-assisted laser desorption ionization-time of flight/mass spectrum (NALDI-TOF/MS) in order to understand cellular response to tetracycline. Of the proteins upregulated in a culture medium containing subinhibitory concentration of tetracycline (50 mug/mL), we identified 38 proteins from cytosol and precipitated fractions by peptide mass fingerprinting and mass spectrum/mass spectrum analysis. Various amino acids ABC transporters, a ribose ABC transporter, and a sulfate ABC transporter were found to be upregulated. Protein synthesis-related proteins, stress proteins, energy metabolic enzymes, and unknown proteins were also strongly induced. Of the identified upregulated proteins, several proteins (isocitrate lyase, branched-chain amino acid ABC transporter, superoxide dismutase, etc.) were also upregulated under phenol-induced stress condition. These results demonstrate that tetracycline at a high concentration induced comprehensive stress in P. putida KT2440 and the global induction of proteins related to bacteria survival. Proteome analysis was found to be a useful tool for the elucidation of antibiotic-induced proteins in the present study.

Bacterial Proteins↗

PubMed2001

Characterization of a novel laccase produced by the wood-rotting fungus Phellinus ribis.

The white-rot fungus Phellinus ribis produced a single form of laccase, which was purified to apparent electrophoretic homogeneity from cultures induced with 2,5-xylidine. This protein was a dimer, consisting of two subunits of 76 kDa as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Carbohydrate analysis revealed that the enzyme contained about 28% carbohydrate content. The laccase appeared to be different from other known laccases by the UV-visible absorption spectrum analysis. One enzyme molecule contained one copper, one manganese, and two zinc atoms. The laccase showed optimal activity at pH 4.0-6.0, 5.0, and 6.0 with 2,6-dimethoxyphenol, ABTS [2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid)], and syringaldazine, respectively. The enzyme preferably oxidized dimethoxyphenol and aromatic amine compounds. The stability of the laccase was low at acidic pH, whereas it showed high stability at neutral pH and mild temperature. The N-terminal amino acid sequence revealed a very low homology with other microbial laccases. With some substrates, the addition of manganese and H2O2 resulted in a remarkable increase in the oxidation rate. Without an appropriate phenolic substrate, the enzyme could not oxidize Mn(II) in the presence of H2O2 or pyrophosphate.

Amino Acid Sequence↗

PubMed1996

Dynamic coherence analysis of vasomotion and flow motion in skeletal muscle microcirculation.

The aim of our study was to determine the cause of fluctuations in microvascular blood flow measured by laser Doppler perfusion monitoring (LDPM) in microvessels of the hamster skin fold preparation. LDPM flow fluctuations (flow motion) were compared to simultaneous records of diameter changes obtained from arterioles and venules. Time-varying coherence analysis was used to quantify the frequency of flow and diameter changes in awake hamsters in control conditions and during sodium nitroprusside-induced vasodilation. Power spectrum analysis of LDPM signals of order 4 and 3 arterioles indicated frequencies of 0.06 +/- 0.01 and 0.08 +/- 0.02 Hz, respectively. Order 3 arterioles exhibited significant temporal coherence between flow motion and vasomotion signals at a frequency of the order of 0.1 Hz. There was lack of coherence when vasomotion was absent in arterioles. Order 4 arterioles had several coherent frequencies in addition to that around 0.1 Hz. In conclusion, time-variant coherence analysis indicated that spontaneous fluctuations in flow are caused by vasomotion of order 3 arterioles with frequency around 0.1 Hz that appears to coordinate local control processes in the microcirculation. Additional frequency components present in LDPM signals are unrelated to vasomotion.

Animals↗

PubMed2004

Self-organization phenomena and decaying self-similar state in two-dimensional incompressible viscous fluids.

The final self-similar state of decaying two-dimensional (2D) turbulence in 2D incompressible viscous flow is analytically and numerically investigated for the case with periodic boundaries. It is proved by theoretical analysis and simulations that the sinh-Poisson state comega=-sinh (betapsi) is not realized in the dynamical system of interest. It is shown by an eigenfunction spectrum analysis that a sufficient explanation for the self-organization to the decaying self-similar state is the faster energy decay of higher eigenmodes and the energy accumulation to the lowest eigenmode for given boundary conditions due to simultaneous normal and inverse cascading by nonlinear mode couplings. The theoretical prediction is demonstrated to be correct by simulations leading to the lowest eigenmode of {(1,0) + (0,1)} of the dissipative operator for the periodic boundaries. It is also clarified that an important process during nonlinear self-organization is an interchange between the dominant operators, which leads to the final decaying self-similar state.

Journal Article↗

PubMed1993

[Variation in the R-R intervals on the electrocardiogram. A new diagnostic method in cardiology].

Periodic heart rate fluctuation depends on the oscillation of sympathetic and vagal activation of the heart. Periodic retardation and acceleration of heart rate related to respiration and to blood pressure changes can be registered on the ECG as the "variability of R-R intervals". Testing procedures of the variability of R-R intervals at rest, during deep breathing, daily activities, during exercise and other stress tests are described in the paper. For the evaluation of the R-R interval's variability, current statistical methods are used (e.g. mean with standard deviation, variation coefficient, mean beat to beat differences in R-R intervals etc.). Power spectral analysis in the variability of 200-600 successive R-R intervals commonly performed today uses either rapid Fourier transformation or the autoregulation model. The analysis shows high- and low frequency peaks corresponding to the rapid and slow oscillations in heart rate. Evaluation of the R-R interval variability, especially using power spectrum analysis, gave good results in testing drugs, e.g., beta blockers, calcium antagonists and antiarrhythmic drugs. Variability of R-R intervals is reduced in conditions affecting the cardiac autonomous nervous system such as diabetes. It is also decreased in patients with ischaemic heart disease and in those with cardiac failure of different aetiology. The decrease is not an expression of the disease itself: it shows an alteration in neurovegetative tonicity in the particular disease condition. The decreased variability of R-R intervals in patients with ischaemic heart disease has an important prognostic value. The predominance of the sympathetic over the depressed vagal activity signalizes an increased risk of sudden coronary death.

Electrocardiography↗

PubMed2005

Time series analysis of ion dynamics in glassy ionic conductors obtained by a molecular dynamics simulation.

We present several characteristics of ionic motion in glassy ionic conductors brought out by time series analysis of molecular dynamics (MD) simulation data. Time series analysis of data obtained by MD simulation can provide crucial information to describe, understand and predict the dynamics in many systems. The data have been treated by the singular spectrum analysis (SSA), which is a method to extract information from noisy short time series and thus provide insight into the unknown or partially unknown dynamics of the underlying system that generated the time series. Phase-space plot reconstructed using the principal components of SSA exhibited complex but clear structures, suggesting the deterministic nature of the dynamics.

Journal Article↗

PubMed2005

Analysis of week-to-week variability in skin blood flow measurements using wavelet transforms.

The study of skin blood flow responses is confounded by temporal variability in blood flow measurements. Spectral analysis has been shown useful in isolating the effects of distinct control mechanisms on various stimuli in the microcirculatory system. However, the sensitivity of spectral analysis to temporal blood blow variability has not been reported. This study was designed to assess week-to-week variability in blood flow measurements using wavelet-based spectrum analysis. Ten healthy, young subjects (mean age+/-SD, 30.0+/-3.1 years) were recruited into the study. Incremental heating (35-45 degrees C, 1 degrees step min-1) was applied on the skin over the sacrum once per week for three consecutive weeks. Wavelet analysis was used to decompose the laser Doppler blood flow signal into frequency bands determined to be associated with endothelial nitric oxide (0.008-0.02 Hz), neurogenic (0.02-0.05 Hz), myogenic (0.05-0.15 Hz), respiratory (0.15-0.4 Hz), and cardiac (0.4-2.0 Hz) control mechanisms. The results showed that coefficients of variation for the power in each frequency band at baseline are smaller than the coefficients of variation of blood flow at baseline or at maximal blood flow ratio (P<0.05). Myogenic and respiratory frequency bands showed the highest coefficients of variation among the five frequency bands. An increase in power in the endothelial nitric oxide frequency band and a decrease in power in the myogenic frequency band of the maximal blood flow response were reproduced in three consecutive weeks. Our study suggests that wavelet analysis is an effective method to overcome temporal variability in skin blood flow measurements.

Adult↗

PubMed1996

Coronary arteries bypass grafting with use of both internal thoracic arteries.

The internal thoracic artery is a preferred conduit for bypass grafting. While the single ITA grafting has been universally accepted -- the use of both ITA's remains controversial. The risk factors analysis based upon assessment of operative results and mid-term functional follow-up was performed. The clinical applicability of transthoracic B-mode ultrasonic imaging and Doppler spectrum analysis in the postoperative evaluation of use of two ITA's was investigated. From January 1989 to January 1993, 97 patients received bilateral ITA and additional vein or RGEA grafts at Groby Road Hospital, Leicester, UK. There were 77 men (79.4%) and 20 women (20.6%) with mean age of 52.1+/-10.1 years. 19 cases were urgent. 14.4% of patients suffered from diabetes mellitus, 8.3% -- COAD and 46.6% did not work because of angina. The average number of anastomoses per patient was 3. The operative mortality was 4.1%. Complications included: reoperation for bleeding=3.2%, sternal infection=6.5%, IABP=2.1%. There were no evidence of perioperative myocardial infarction. 80 patients were followed-up for 26,5+/-13 months. 49 patients were in angina NYHA class I while preoperatively: 7. 1 patient was in NYHA class III while preoperatively there were 40 patients. Nearly twice more patients worked, and more than three times fewer patients did not worked because of angina, comparing to preoperative period. With the use of colour Doppler technique the blood flow was measured in 78.3% of left and 74% of right ITA's. The average flow in left ITA was: 46.4+/-17 ml/min and 41.7+/-17 ml/min in right ITA. The multivariate analysis for risk factors of bilateral ITA's grafting was performed. There were no risk factors for postoperative complications of bilateral internal thoracic arteries grafting in presented material. The risk of perioperative death is higher for patients with triple vessels disease than for patients with double vessels disease. Bilateral ITA grafting procedure has positive influence on patients working abilities. Percutaneous ultrasonic assessment of flow in ITA's used for bypass appears to be useful non-invasive investigation of their function.

Coronary Disease↗

PubMed1997

Digital communication with fetal monitors.

BACKGROUND: Fetal heart rate (FHR) values in the averaged format that are provided by commercial computed cardiotocography analysis systems may be unsuitable for special analysis purposes. METHOD: I developed a communication software program to obtain any measured values of fetal monitors for individual analysis of computed cardiotocography. EXPERIENCE: The software program was used to study the data continuity of beat-to-beat FHR values as an experiment for chaos theory and power spectrum analysis. The results indicated that the signal loss was recognized at a precision of 95%. CONCLUSION: The described method of digital communication with fetal monitors was found to be useful for individual purposes in the field of computed cardiotocography analysis.

Algorithms↗

PubMed2006

Reduced heart rate variability and baroreflex sensitivity in primary biliary cirrhosis.

BACKGROUND: Standardized mortality ratio for primary biliary cirrhosis (PBC) is 2.87. Even after accounting for liver and cancer-related deaths there is an unexplained excess mortality associated with PBC. We have assessed heart rate variability (HRV) and baroreflex sensitivity (BRS) risk factors associated with cardiovascular mortality, in 57 PBC patients and age- and sex-matched normal controls. METHODS: HRV and BRS were measured non-invasively in subjects and controls. Beat to beat RR interval and 'Portapres' blood pressure data were processed using power spectral analysis. Power was calculated in very low frequency (VLF), low-frequency (LF) and high-frequency (HF) bands according to international guidelines. BRS (alpha) was computed using cross-spectrum analysis. Patients also underwent fatigue severity assessment using a measure validated for use in PBC. RESULTS: PBC patients had significantly lower total HRV compared with controls (P=0.02), with the reduction occurring predominantly in the LF domain (P=0.03). BRS was also significantly reduced compared with controls (P=0.02). There were no significant differences in HRV or BRS between cirrhotic and non-cirrhotic patients. Within the PBC patient group HRV was significantly lower in fatigued than in non-fatigued patients (P<0.05). CONCLUSION: Abnormalities of HRV and BRS in PBC are not specific to advanced disease but are associated with fatigue severity. Abnormalities could be associated with increased risk of sudden cardiac death, potentially contributing to the excess mortality seen in PBC.

Aged↗

PubMed1993

Small-conductance Cl- channels in rabbit parietal cells activated by prostaglandin E2 and inhibited by GTP gamma S.

1. Small-conductance, sub-picosiemens (sub-pS) Cl- channels in the basolateral membrane of non-stimulated parietal cells in isolated rabbit gastric glands were studied by whole-cell patch-clamp and noise analysis techniques. 2. Voltage-independent whole-cell Cl- currents were recorded from parietal cells equilibrated with Cl(-)-containing solutions. Intracellular application of guanosine-5'-O-(3-thiotriphosphate) (GTP gamma S, 5-200 microM) slowly decreased the whole-cell Cl- current, and its steady-state effect was observed about 6 min after the start of the dialysis. The half-maximal inhibitory concentration of GTP gamma S was about 60 microM. 3. The single Cl- channel conductance was estimated to be 0.37 pS from the variance noise analysis during the GTP gamma S-induced inhibitory process of the whole-cell Cl- current. It is in agreement with the value obtained by a method of power spectrum analysis (0.47 pS). 4. The whole-cell Cl- current was increased by prostaglandin E2 (10 microM). The increased Cl- current was reduced by the subsequent application of GTP gamma S (50 microM), whereas the GTP gamma S (50 microM)-induced inhibition of the Cl- current was not reversed by the subsequent application of prostaglandin E2 (10 microM). 5. The combined intracellular application of GTP gamma S (50 microM) and GDP beta S (500 microM) markedly reduced the inhibitory effect of GTP gamma S, indicating that a GTP-binding protein is involved in the regulation of the Cl- channel. 6. Treatment of parietal cells with pertussis toxin (PTX, 500 ng/ml) for 90-140 min did not affect the GTP gamma S-induced inhibition of the whole-cell Cl- current. 7. Intracellular application of cyclic AMP-dependent protein kinase inhibitor peptide (100 micrograms/ml) or 1,2-bis(O-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA) (5 mM, pCa 8) did not affect the GTP gamma S-induced inhibition of the whole-cell Cl- current. 8. The present study has suggested that the opening of the sub-pS Cl- channel is modulated negatively by a PTX-insensitive GTP-binding protein and positively by prostaglandin E2.

Animals↗

PubMed1981

Synergistic behavior of inspiratory muscles after diaphragmatic fatigue in the newborn.

We studied diaphragmatic and intercostal muscle activity and the pattern of motion of rib cage and abdomen after diaphragmatic muscle fatigue in 15 newborn infants (birth wt 1,251 +/- 424 g, mean +/- SD). Rib cage and abdominal motion were monitored with magnetometers and intercostal and diaphragmatic electromyograms (EMG's) with surface electrodes. Twelve infants showed a total of 66 episodes of muscle fatigue identified by EMG frequency spectrum analysis. Two patterns of responses to fatigue were observed. In the first case, five infants consistently recruited their intercostal muscles; this was followed by a normalization of the diaphragmatic frequency spectrum. In these infants, recruitment of intercostal muscles successfully prevented any clinical deterioration. In the second, seven infants showed no change in their intercostal muscle activity, and diaphragmatic fatigue was followed by apnea. We conclude that in newborn infants the synergistic behavior of the diaphragm and intercostal muscles can maximize the performance of these muscles and, in some infants, seems to prevent development of apnea.

Apnea↗

PubMed1992

Spectral analysis of heart rate variability in bronchial asthma.

Sympathetic and parasympathetic activity was evaluated in ten healthy controls, nine asymptomatic, untreated asthmatic subjects and ten asthmatic patients during treatment for acute asthma, by measurement of the variation in resting heart rate using frequency spectrum analysis. Heart rate was recorded by ECG and respiratory rate by impedance plethysmography. Spectral density of the beat-to-beat heart rate was measured within the low frequency band 0.04 to 0.10 Hz (low frequency power) modulated by sympathetic and parasympathetic activity, and within a 0.12 Hz band width at the respiratory frequency mode (respiratory frequency power) modulated by parasympathetic activity. Acute asthmatics had higher heart rates than either of the other two groups; this was probably related to the effects of beta-adrenoceptor agonist medication. Sympathetically mediated heart rate variability (normalized low frequency power) was significantly lower in both asymptomatic (p less than 0.002) and acute (p less than 0.02) asthma subjects compared to controls. This is consistent with altered sympathetic/parasympathetic regulation of heart rate in subjects with bronchial asthma.

Adult↗

PubMed2000

Kinetic and frequency-domain properties of reflex and conditioned eyelid responses in the rabbit.

Eyelid position and the electromyographic activity of the orbicularis oculi muscle were recorded unilaterally in rabbits during reflex and conditioned blinks. Air-puff-evoked blinks consisted of a fast downward phase followed sometimes by successive downward sags. The reopening phase had a much longer duration and slower peak velocity. Onset latency, maximum amplitude, peak velocity, and rise time of reflex blinks depended on the intensity and duration of the air puff-evoking stimulus. A flashlight focused on the eye also evoked reflex blinks, but not flashes of light, or tones. Both delayed and trace classical conditioning paradigms were used. For delayed conditioning, animals were presented with a 350-ms, 90-dB, 600-Hz tone, as conditioned stimulus (CS). For trace conditioning, animals were presented with a 10-ms, 1-k/cm(2) air puff, as CS. The unconditioned stimulus (US) consisted of a 100-ms, 3-k/cm(2) air puff. The stimulus interval between CS and US onsets was 250 ms. Conditioned responses (CRs) to tones were composed of downward sags that increased in number through the successive conditioning sessions. The onset latency of the CR decreased across conditioning at the same time as its maximum amplitude and its peak velocity increased, but the time-to-peak of the CR remained unaltered. The topography of CRs evoked by short, weak air puffs as the CS showed three different components: the alpha response to the CS, the CR, and the reflex response to the US. Through conditioning, CRs showed a decrease in onset latency, and an increase in maximum amplitude and peak velocity. The time-to-peak of the CR remained unchanged. A power spectrum analysis of reflex and conditioned blink acceleration profiles showed a significant approximately 8-Hz oscillation within a broadband of frequencies between 4 and 15 Hz. Nose and mandible movements presented power spectrum profiles different from those characterizing reflex and conditioned blinks. It is concluded that eyelid reflex responses in the rabbit present significant differences from CRs in their profiles and metric properties, suggesting different neural origins, but that a common approximately 8-Hz neural oscillator underlies lid motor performance. According to available data, the frequency of this putative oscillator seems to be related to the species size.

Air Movements↗