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At least 1,099 records · Page 61Linked to original sources
PubMed1989

Involvement of fast synaptic inhibition in the generation of high-frequency oscillation in central respiratory system.

During moderate hypercapnia, spectrum analysis of efferent phrenic nerve activity (PNA) of urethane anesthetized rabbits revealed high-frequency oscillations (HFO). The spectral peak (mean frequency 111 Hz) was reversibly eliminated by the glycine receptor antagonist strychnine administered into the 4th cerebral ventricle. In contrast, blockade of brainstem GABAA receptors by bicuculline did not abolish HFO but even reinforced or induced HFO. Thus, there is evidence that fast synaptic inhibition via glycine receptors is involved in the generation of HFO within the medullary respiratory center, whereas GABA may play a modulatory role.

Action Potentials↗
PubMed1979

Foreign material in the capsules around breast prostheses and the cellular reaction to it.

Thirteen capsules which had formed around breast prostheses were examined, using the technique of splitting the capsule wall. A foreign material in droplet form was present in all the capsules. The foreign material was taken up by phagocytes, and the cytological evidence is that it has cytotoxic activity. It was shown that the material migrates to the vessels in the outer layer of the capsule and may reach the lumen of those vessels. On the basis of the microscopic appearance and the results of infrared spectrum analysis, the foreign material in the capsules was assumed to be silicone.

Breast↗
PubMed1992

Complete 1H- and 13C-resonance assignments for D-mannooligosaccharides of the beta-D-(1-->2)-linked series released from the phosphopeptidomannan of Candida albicans VW.32 (serotype A).

D-Mannooligosaccharides (dp 1 to > 17) were released by mild acid hydrolysis from the phosphopeptidomannan of a Candida albicans strain of A serotype (VW.32). Among these, mannooligosaccharides ranging from bi- to hepta-ose, which were obtained in appreciable amounts, were structurally investigated and found to belong to the beta-D-(1-->2)-linked series. The occurrence of such compounds has already been reported in other Candida albicans strains. The complete 1H- and 13C-resonance assignments for manno-tri- to manno-hepta-ose are reported and general rules applicable for the 1NMR spectrum analysis of linear mannooligosaccharide of the general structure, beta-D-Man p-(1-->2)-[beta-D-Man p-(1-->2)]n-beta-D-Man p are proposed.

Acids↗
PubMed1984

A pain microcomputer system for clinical and laboratory investigation.

This report describes the design and use of a mobile "Pain Microcomputer System" (PMS). As a mobile clinical and laboratory research tool the PMS integrates four functions: (1) psychophysical measurement of behavioral pain responses; (2) psychophysiologic recording, including brain evoked potentials, cortical power spectrum analysis, EKG and EMG; (3) data acquisition, analysis and display; (4) peripheral communications via modem allows interaction with larger computers for more complex data analyses, extensive graphics, etc. A word processor disk facilitates writing of scientific and clinical reports. Present and future capabilities of the system for comprehensive pain research and patient care are discussed.

Animals↗
PubMed1976

EEG changes during spontaneous and controlled menstrual cycles and their correlation with psychological performance.

1. EEG (occipito-central, anterior and posterior temporo-central), blood concentration of hormones (oestradiol, progesterone, prolactin, folliculo-stimulating (FSH) and luteinizing (LH) hormones) and psychometric tests (reaction time, concentration, simple calculations, visual orientation and simple motor performance tasks) were recorded from 16 young women during a spontaneous menstrual cycle (s.c.w. group) and from 16 women taking combined oral contraceptives (o.c.w. group). All data were collected every second day except Sundays. 2. The EEGs underwent power spectrum analysis. Power and weighted mean frequency were determined for different frequency bands (theta, alpha and beta). The most constant finding in the s.c.w. group was a slight increase of mean alpha frequency during the luteal phase until menstruation (mean of occipital alpha acceleration = +0.3c/sec). The average time course of this acceleration fitted the time course of progesterone increase, but no direct correlation could be established. No such acceleration of alpha frequency could be found in the o.c.w. group, but the mean frequency in this group was about 0.5c/secslower than that of the s.c.w. group. In addition, minor cyclic changes of EEG paramenters in the s.c.w. group were observed in the occipital and temporal theta activity, the temporal alpha activity, but none in the beta range. 3. Reaction times to simple tasks, simple arithmetic, etc. were slightly but significantly decreased in the s.c.w. group during the luteal phase with a minimum on the day before or during menstruation. No such changes were observed in the o.c.w. group, which performed, in all tasks, slightly slower and slightly less correctly than the s.c.w. group. 4. The individual relative accelerations of alpha frequency and shortening of reaction times were positively correlated with each other.

Adult↗
PubMed1977

Sleep patterns in mental retardation: Down's syndrome.

EEG and eye movements during two consecutive nights were recorded in 21 "normal" and 21 Down's subjects of both sexes in the 14-24-year age range. Records of most Down's subjects were characterized by longer total sleep time, lack of waking alpha, frequent awakening and movement epochs and fewer spindle bursts. Significantly longer "awake" and stage 4 percentages, but less stage 2, were found in the Down's group. They also had longer REM latency, and lower eye movement density based on number of eye movements. Density based on integrated eye activity correlated positively with IQ in the Down's subjects. Spectrum analysis for EEG frequencies from 1 to 20 c/sec showed significantly greater power in the Down's group below 9 and above 12 c/sec, but no difference in the alpha range. The greater power at low frequencies was more pronounced in "awake", stage 1 and REM.

Adolescent↗
PubMed1986

Does an ACTH derivative (Org 2766) prevent deterioration of EEG in Alzheimer's disease?

Seventy-seven patients with Alzheimer's disease were submitted to a double-blind no cross-over study of the effect of a synthetic ACTH4-9 analog (Org 2766) on the EEG. The quantitative EEG power spectrum analysis with 22 Org 2766 and 22 placebo treated patients showed no improvement which could be related to the Org 2766 medication (6 months, 40 mg daily), either comparing the successive EEG sessions or comparing the drug treated group with the placebo treated group. The placebo treated group showed a decrease of power in the beta band after 4 and 6 months and an increase of theta after 6 months, which is regarded as a sign of deterioration of the EEG in advancing disease. These changes did not occur in the Org 2766 treated group. However, a subgroup analysis of 9 Org 2766 treated patients and 9 placebo treated patients without other CNS drugs during the study did not reveal consistent differences between the groups after 4 and 6 months of therapy. We believe that Org 2766 does not have a long-term protecting effect on the EEG.

Adrenocorticotropic Hormone↗
PubMed1978

Electroencephalographic study of the short-acting hypnotics etomidate and methohexital in dogs.

Beagles, implanted with cortical and subcortical electrodes, were given etomidate i.v. (1 mg/kg) over a period of 10 sec. The effects on the EEG were compared with those obtained with 7 mg/kg of methohexital. Both compounds induced hypnosis for a duration of approximately 8 min. The EEGs showed a remarkable similarity. Visual inspection of the records as well as power spectrum analysis revealed a sustained theta-activity with underlying fast activity. The configuration of the waves was rather sharp. The power obtained after etomidate was, however, 2 to 3 times that obtained after methohexital. When the animals awoke from etomidate-induced hypnosis slow waves appeared and were followed by alpha-activity, whereas after methohexital-hypnosis beta-activity predominated. Etomidate slightly increased heart rate, but respiratory depression was not observed. Methohexital caused pronounced tachycardia and apnoea. In 3 out of 6 dogs methohexital caused myoclonus of the hind legs upon awakening from anaesthesia. Etomidate induced myoclonus in one dog during hypnosis.

Animals↗
PubMed1996

Characterization of recombinant human HBP/CAP37/azurocidin, a pleiotropic mediator of inflammation-enhancing LPS-induced cytokine release from monocytes.

Neutrophil-derived heparin-binding protein (HBP) is a strong chemoattractant for monocytes. We report here for the first time the expression of recombinant HBP. A baculovirus containing the human HBP cDNA mediated in insect cells the secretion of a 7-residue N-terminally extended HBP form (pro-HBP). Deletion of the pro-peptide-encoding cDNA sequence resulted in correctly processed HBP at the N-terminus. Electrospray mass spectrum analysis of recombinant HBP yielded a molecular weight of 27.237 +/- 3 amu. Consistent with this mass is a HBP form of 225 amino acids (mature part +3 amino acid C-terminal extension). The biological activity of recombinant HBP was confirmed by its chemotactic action towards monocytes. Furthermore, we have shown that recombinant HBP stimulates in a dose-dependent manner the lipopolysaccharide (LPS)-induced cytokine release from human monocytes.

Animals↗
PubMed1996

A novel two-site binding equation presented in terms of the total ligand concentration.

For the most frequently used two-site model, an exact binding equation is presented in terms of the total ligand concentration. This equation has been extended to analyze the spectroscopic titration experiment where the dilution of protein solution cannot be neglected, the displacement study, and the effect of non-specific binding. Thus, with a non-linear regression program, all unknown binding parameters can be determined correctly by fitting these equations to the experimental data without any data transformation. As an example of the use of the new equations, the experimental data for receptor-insulin binding were taken from literature and reanalyzed by using a non-linear regression data analysis program.

Binding Sites↗
PubMed1995

K-ras-2 G-C and G-T transversions correlate with DNA aneuploidy in colorectal adenomas.

BACKGROUND/AIMS: K-ras-2 mutations and DNA content heterogeneity represent early events of human colorectal tumor progression. The aim of the study was to investigate if specific K-ras-2 mutations in 58 human sporadic adenomas were correlated with DNA aneuploidization and cell proliferation. METHODS: Multiparameter flow cytometry, based on scatter parameters and DNA content, was performed using 4,6-diamidino-2-phenilindole-2-hydrochloride-stained nuclei obtained from adenoma fragments with either mild-moderate or severe dysplasia. K-ras-2 polymerase chain reaction and spectrum analysis were performed using sorted DNA specific epithelial subclones. RESULTS: We detected six G-A transitions, and four G-C and two G-T transversions. The DNA aneuploid subclones were 25 with DNA index values in the near diploid region (DNA index < 1.3) for the vast majority of cases (80%). DNA aneuploidy among the mutated adenomas with G-A transitions was 1 of 6 (17%) and 6 of 6 (100%) among G-C and G-T transversions. Although DNA aneuploidy and high S-phase values were also present among K-ras-2 wild-type adenomas, their statistical associations with K-ras-2 status were P < 0.005 and P < 0.05, respectively. CONCLUSIONS: The present series of sporadic colorectal adenomas indicates that codon 12 G-C and G-T K-ras-2 transversion mutations and DNA aneuploidy are correlated. The underlying mechanisms that explain such association remain to be investigated.

Adenoma↗
PubMed1987

Loss of control biomechanics of the human arm-elbow system.

An experimental study was conducted to determine whether external disturbance oscillations, such as those that could be created by hand held tools, alter the dynamic response characteristics of the human arm-muscle system. A special arm-test frame was used to induce external sinusoidal torque oscillations of various amplitudes and frequencies, while the reaction force and angular displacement were monitored. Two different output variable frequency responses were determined using input/output cross-spectrum analysis. The angular displacement of the test frame and a component of hand reaction force were the output variables used, while the test frame torque was the input. Test results from one subject are presented in this paper. Changes in the magnitude and phase angle of the frequency responses were observed for different frequencies of the disturbance torque. These changes indicate that the stability margin and response amplitude of the human arm-muscle system do change as a function of the frequency and amplitude of external disturbance oscillations. This suggests that at certain operating frequencies hand held tools can induce large reaction amplitudes or even loss of control.

Arm↗
PubMed1992

Three-dimensional structure in solution of acyl-coenzyme A binding protein from bovine liver.

The three-dimensional structure of acyl-coenzyme A binding protein as encoded by the recombinant gene in Escherichia coli has been determined using nuclear magnetic resonance (n.m.r.) spectroscopy. The structure consists of four alpha-helices A1 (residues 3 to 15), A2 (residues 20 to 36), A3 (residues 51 to 60), and A4 (residues 65 to 85). A1 and A4, and A2 and A3, run in parallel pairs. A2 runs anti-parallel to A1 and A4. The three-dimensional structure of the protein is reminiscent of a shallow bowl with a rim. The "rim" is characterized by many polar and charged groups, whereas the inside and outside surface is predominantly hydrophobic with patches of uncharged polar hydroxyl groups of threonyl, serinyl and tyrosyl residues. The inside bottom contains through two epsilon-amino groups of lysine residues (Lys13 and Lys32) suggesting that the binding site for the nucleotide part of the acyl-coenzyme A part of the ligand molecule is at the inside surface of the bowl. The structure determination was done on the basis of measurements of the intensities of nuclear Overhauser effects (NOEs) and coupling constants that were translated into interatom distance restraints for 833 atom pairs, and 87 dihedral angle restraints, of which 23 were in chiral centers. In all, 42 hydrogen bonds were identified by n.m.r. and provided an additional 84 distance restraints. A total of 20 structures were calculated and the structures can be aligned to a root-mean-square deviation of 0.5 A for the backbone atoms of the residues in the four helices. A region of six residues could not be defined by the restraints obtained by n.m.r. The program Pronto was used for the spectrum analysis in general, and especially for the assignment of the individual NOEs, the integration of the cross peaks, and the measurements of the coupling constants. The programs DIANA and X-PLOR have been used in the structure calculations and evaluations.

Animals↗
PubMed1993

Masseter muscle fatigue during sustained clenching in subjects with complete dentures, implant-supported prostheses, and natural teeth.

A sustained submaximal (50%) clenching effort was performed in four patient groups to establish whether implant-supported prosthetic reconstructions influence myoelectrical signal parameters. The first group consisted of patients with natural teeth in both jaws. The other three groups consisted of patients who were edentulous in both jaws: one group had complete dentures; one had an overdenture in the mandible on two implants connected by a bar; and the third had an implant-supported fixed prosthesis in either the maxilla or the mandible. Surface electromyography indicated an increased myoelectrical output level that paralleled a higher bite force level for implant-supported reconstructions compared with complete dentures. Power spectrum analysis revealed a downward shift of the mean power frequency during sustained clenching in all groups except the implant-supported fixed prosthesis. The absence of a spectral shift in the latter group probably reflected a fear of biting too hard and fracturing the prosthesis.

Adult↗
PubMed1984

The effects of alpha- or beta-adrenergic receptor agonists and antagonists and calcium entry blockers on the spontaneous vasomotion.

The effects of systemic injections of vasoactive substances were studied in the micro-circulation of the hamster skin fold window preparation, which can be observed without anesthesia, exposure, and acute surgical procedures. The effects were characterized by the continuous measurement of the diameter of the arterial microvessels ranging from 100 to 8 micron. Power spectrum analysis was utilized to determine the frequency and the amplitude of the fundamental component of spontaneous diameter changes. Epinephrine and norepinephrine increased the frequency of vasomotion and reduced mean diameter at low dosages. Phentolamine reduced the frequency of vasomotion and increased mean diameter. Propranolol increased the frequency of vasomotion and did not significantly change mean diameter. Adenosine and verapamil suppressed vasomotion and increased mean diameter. These results are explained by postulating that low-dosage alpha-adrenergic receptor stimulation facilitates the spontaneous discharge of smooth muscle cells; beta-adrenergic receptor stimulation has the opposite effect, whereas beta-adrenergic receptor inhibition also enhances the vasomotor effect. Calcium entry blockers abolish the rhythmic discharge. This explanation of the activity of the various substances supports the hypothesis that the spontaneous vasomotion of the arterial microvessels is related to the intrinsic property of smooth muscle cells.

Adrenergic alpha-Agonists↗
PubMed1989

Role of ruvAB genes in UV- and gamma-radiation and chemical mutagenesis in Escherichia coli.

Escherichia coli umuC122::Tn 5 was mutagenized with N-methyl-N'-nitro-N-nitrosoguanidine to isolate mutations that block the residual gamma-radiation mutagenesis observed in umuC strains. Two of these mutations were shown by transductional mapping and plasmid complementation to map in the ruvA and ruvB genes (i.e., ruvA200 and ruvB201). Whereas ruvA200 was complemented by ruvA+ plasmids, the only other known ruvA mutation, ruvA59::Tn10 required both the ruvA+ and ruvB+ genes to show complementation. The ruvA200, ruvB201, ruvA59::Tn10 and ruvB60::Tn10 mutations all reduced gamma-radiation-induced ochre reversion [argE3(Oc)----Arg+] to about 30% of the wild-type level, and they all reduced UV-radiation-induced ochre reversion to about 15% of the wild-type level. The ruvA200 and ruvB201 mutants also showed reduced gamma- and UV-radiation mutagenesis with two other assays [hisG4(Oc)----His+ and Rifs----Rifr]. Streptozotocin mutagenesis (Rifr) was reduced to about half of the wild-type level in ruv strains, but ethyl methanesulfonate mutagenesis was normal. While the umuC strain did not show the oxygen enhancement of gamma-radiation mutagenesis, the ruvA200 strain showed an oxygen effect that was similar to that shown by the wild-type strain. When the ruvA200 mutation was combined with the umuC mutation, gamma-radiation mutagenesis was further reduced to 5% of the wild-type level and cells showed a synergistic sensitization to UV- and gamma-radiation-induced killing. A mutational spectrum analysis indicates a general depression of both umuC-dependent and umuC-independent gamma-radiation mutagenesis in the ruvA strain, which is in contrast with the site-specific reduction in gamma-radiation mutagenesis that is observed in the umuC mutant. The reduced radiation mutagenesis in the ruvA strain could not be correlated with a reduction in transcription of the recA or umuC genes.

Bacterial Proteins↗
PubMed1983

Ultradian rhythms in cognitive functions and their relationship to visceral processes.

Visceral and behavioral data were repeatedly sampled over time in 7 men performing tests of eye-hand coordination and of recall. Spectrum analysis of behavioral data showed peaks in the ultradian range which for the group were significantly different from white noise. Relations between visceral and behavioral data were not striking. However, relations between (a) epinephrine and indices of sympathetic tone (i.e., norepinephrine or heart rate) and (b) ongoing performance were positive and the highest of all tested.

Activity Cycles↗
PubMed1988

Estrous correlated modulations of circadian and ultradian wheel-running activity rhythms in LEW/Ztm rats.

Estrogen treatment alters the expression of ultradian activity rhythms in male and female LEW/Ztm rats. This finding raises the possibility that the expression of ultradian rhythms may vary on different days of the estrous cycle. To test this hypothesis, we recorded the circadian and ultradian wheel-running activity rhythms of entrained (LD 12:12) and free-running sexually mature LEW/Ztm females during their 4- or 5-day estrous cycle. The mean daily activity, the duration of activity, the circadian period of activity, and the occurrence of ultradian rhythms differed significantly among the days of the estrous cycle. In LD 12:12, the phase angle difference between the beginning of activity and light offset varied reliably in 5-day cycling animals. The highest daily mean of activity, the longest duration, and the shortest circadian period length were observed on the day of estrus in both entrained and free-running animals. The day of estrus was characterized by a constant high level of activity throughout the activity phase, while the days following ovulation showed a bi- or trimodal activity pattern. Power spectrum analysis revealed significant ultradian components for the days of metestrus and diestrus, but only circadian components for the days of proestrus and estrus. These results were interpreted as indicating that endogenous changes in circulating hormone levels can induce changes in the ultradian and circadian patterns of wheel-running activity in LEW/Ztm rats.

Animals↗