Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    EFFECT OF HAEMORRHAGE ON THE POWER OF LOW FREQUENCY BLOOD PRESSURE FLUCTUATIONS IN YOUNG SPONTANEOUSLY HYPERTENSIVE RATS (1995)
    Oxford, UK : Blackwell Publishing Ltd
    Clinical and experimental pharmacology and physiology 22 (1995), S. 0 
    Details
    ISSN: 1440-1681
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: 1. Before the onset of hypertension low frequency (0.04– 0.1 Hz) MAP fluctuations are reduced in SHR when compared to WKY. We studied the effect of haemorrhage under α1 blockade or angiotensin converting enzyme inhibition (CEI) on the power spectra (PS) of each strain.2. MAP was recorded from the caudal artery in conscious, 1 month old SHR and WKY. Three groups of rats were studied. Group 1, acute 2 mL haemorrhage; groups 2 and 3, injection of prazosin (0.25–2.5 mg/kg) or captopril (O.5–4 mg/kg), followed by haemorrhage, as in group 1. The PS was divided into 3 frequency bands, 0.004–0.04,0.04–0.07 and 0.07–0.1 Hz.3. In SHR, although the baseline MAP levels were similar to those of WKY, the PS was significantly damped in each of the 3 frequency bands.4. Haemorrhage induced a similar MAP fall in both strains accompanied by an increase in the slow MAP fluctuations. However, in SHR the PS response was significantly greater than in WKY. The biggest response was in the slowest (0.004–0.04 Hz) frequency band, 8.7 ± 1.7 vs 1.5 ± 0.4 times baseline levels, respectively.5. The difference between the two strains in the PS response to haemorrhage was eliminated by α1 blockade. The exaggerated response observed in haemorrhaged, unblocked SHR was reduced in the 3 frequency bands.6. Captopril reduced the PS response to haemorrhage in SHR to the level observed in WKY in all 3 frequency bands.7. The enhanced amplification of the MAP fluctuations in haemorrhaged SHR may indicate that SHR requires greater recruitment of control mechanisms than WKY to maintain MAP at a similar level to WKY.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1440-1681.1995.tb02843.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Rhythm of sounds produced by larvae of the oriental hornet Vespa orientalis: Spectral analysis
    Amsterdam : Elsevier
    Biosystems 19 (1986), S. 299-305 
    Details
    ISSN: 0303-2647
    Keywords: Acoustical communication ; Fourier transform ; Hunger signal ; Social insects ; Ultradian rhythm
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1016/0303-2647(86)90007-9
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Electro-mechanical noise in atrial muscle fibres of the carp (1977)
    Springer
    Cellular and molecular life sciences 33 (1977), S. 1058-1060 
    Details
    ISSN: 1420-9071
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Steady membrane voltage fluctuations have been observed in atrial muscle fibres of the carp. These voltage fluctuations produce minute mechanical oscillations, as revealed by an interference contrast microscope. The steady voltage fluctuations may be related to abnormal automaticity in the heart.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01945968
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Offset rate of action of muscarinic antagonists depends on their structural flexibility (1979)
    Springer
    Cellular and molecular life sciences 35 (1979), S. 650-652 
    Details
    ISSN: 1420-9071
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Time course measurements of the action of muscarinic antagonists were performed in the spontaneously beating carp atrium. Several high affinity drugs, which embody the quinuclidine structure were examined. The structural flexibility of these molecules was reflected in the dissociation of the drugs from the muscarinic receptor. The dissociation of rigid drugs was very much prolonged as compared to flexible drugs of the same affinity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01960378
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Interrelationships among measures of autonomic activity and cardiovascular risk factors during orthostasis and the oral glucose tolerance test (1995)
    Springer
    Clinical autonomic research 5 (1995), S. 271-278 
    Details
    ISSN: 1619-1560
    Keywords: stress ; sympathetic nervous system ; catecholamines ; parasympathetic nervous system ; heart rate ; spectral analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Overstimulation of sympathetic nervous system activity is related to atherosclerotic cardiovascular disease risk, but the role of parasympathetic activity in this association is not clear. This study evaluated sympathetic and parasympathetic function by spectral analysis of heart rate variability and plasma levels of norepinephrine (NE) epinephrine (EPI), dihydroxyphenylglycol (DHPG), dihydroxyphenylalanine (DOPA) and dihydroxyphenylacetic acid (DOPAC). It also examined the interrelationships among these parameters and established atherosclerotic cardiovascular disease risk factors in 53 men (mean age 59.5 years). During supine rest, low-frequency power correlated positively with high-frequency power (r = 0.58, p 〈 0.001), plasma NE correlated with plasma DHPG (r = 0.41, p 〈 0.001) and plasma DOPA with DOPAC (r = 0.47, p 〈 0.001) but neither low- nor high-frequency power was correlated with plasma levels of any catechol. Among risk factors, plasma NE correlated with fasting insulin and mean arterial blood pressure, and urine NE correlated with body mass index. Both low- and high-frequency power correlated positively with insulin levels. Orthostasis decreased high-frequency power and increased low-frequency power and plasma NE levels. During the oral glucose tolerance test, both high- and low-frequency power increased, plasma NE levels were unchanged, and plasma EPI levels decreased [88.5 ± 18 (SEM) versus 52.5 ± 12 pM,p = 0.001]. The results suggest that orthostasis decreases and the oral glucose tolerance test increases parasympathetic outflows, whereas both stimuli increase sympathetic outflows. Among all atherosclerotic cardiovascular disease risk factors, hyperinsulinaemia showed the strongest association with autonomic nervous system activity, especially parasympathetic activity. Estimates of sympathetic responses obtained from power spectral analysis of heart rate variability agree poorly with those from plasma levels of catechols, possibly because of a parasympathetic contribution to low-frequency power and independence of sympathoneural outflows to the arm and heart.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01818892
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Insulin resistance and autonomic function in traumatic lower limb amputees (1995)
    Springer
    Clinical autonomic research 5 (1995), S. 279-288 
    Details
    ISSN: 1619-1560
    Keywords: insulin resistance ; sympathetic nervous system ; catecholamines ; parasympathetic nervous system ; amputees ; spectral analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract This study examined plasma insulin response to oral glucose load and autonomic nervous system activity in male lower limb amputees (n = 52) aged 50–65 years, compared to matched controls (n = 53). The groups had similar body mass index, blood pressure and plasma lipid levels. The amputees had higher mean fasting plasma insulin levels (18.4 ± 9.7 (SD) versus 13.7 ± 5.1 m U/l,p = 0.005) and during an oral glucose tolerance test (OGTT) (1 h levels 88.1 ± 45.3 versus 62.1 ± 42.7,p = 0.016) with similar plasma glucose levels, indicating insulin resistance. At baseline with the subjects supine, there were no group differences in low- or high-frequency power of heart rate variability or in plasma levels of norepinephrine (NE) or epinephrine (EPI). In response to orthostasis, the groups had similarly increased plasma NE levels. During the OGTT, amputees had significantly larger increments in low-frequency power than did controls (2.2 ± 1.3 versus 1.6 ± 0.9 (beats/min)2 respectively,p 〈 0.01) and plasma NE levels increased significantly in amputees (1595 ± 849 versus 1941 ± 986 pM,p = 0.0008) but not in controls. At 1 h after glucose administration, plasma EPI levels were decreased significantly from baseline in both groups; at both 1 and 2 h after glucose administration, plasma EPI levels were higher in the amputees than controls. Amputees appear to have a combination of enhanced sympathoneural responsiveness and attenuated suppression of adrenomedullary secretion during glucose challenge. As catecholamines antagonize insulin effects, one possible explanation for insulin resistance in amputees is hyperglycaemia-induced sympathoneural activation and a failure of hyperglycaemia to decrease adrenomedullary secretion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01818893
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Artefacts in standard and time-dependent spectral analysis of arterial blood pressure signals obtained by Finapres: Importance and correction (1995)
    Springer
    Clinical autonomic research 5 (1995), S. 295-301 
    Details
    ISSN: 1619-1560
    Keywords: Finapres ; heart rate variability ; selective discrete Fourier transform algorithm (SDA) ; arterial blood pressure ; spectral analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The non-invasive Finapres (finger arterial pressure) device is widely used for the measurement of arterial blood pressure (BP) in BP variability studies, in particular in experimental studies. In our work, we have noticed that the calibration pauses of the Finapres, occurring approximately every 80 heart beats, introduce artefacts in standard and time-dependent spectral analysis of the arterial BP signal. This report describes these artefacts and indicates their dependence on the heart rate (HR) of the subject. In standard spectral analysis, they appear principally for low HR subjects, whereas in time-dependent spectral analysis, they distort the time-dependent spectrum both for low and high HR subjects. A possible correction procedure is presented which eliminates these pauses, causing minimal distortion from the original arterial BP time series. This correction keeps the total time-duration of the corrected signal equal to that of the original signal, thus allowing reliable spectral analysis of arterial BP fluctuations to be performed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01818895
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Spectral analysis of heart rate in vasovagal syncope: The autonomic nervous system in vasovagal syncope (1993)
    Springer
    Clinical autonomic research 3 (1993), S. 261-269 
    Details
    ISSN: 1619-1560
    Keywords: Autonomic nervous system ; Fainting ; Heart rate fluctuations ; Spectral analysis ; Tilt ; Vasovagal syncope
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Spectral analysis of heart rate fluctuations was used to investigate the role of the autonomic nervous system in the pathogenesis of vasovagal syncope. Nine adolescents with a history of at least three episodes of vasovagal syncope and nine age-matched healthy controls were studied. All subjects were tested in supine position and at a 60° inclination for 60 min or less if syncope developed. Blood pressure and heart rate were measured, while the ECG and respiration traces were recorded on magnetic tape for later spectral analysis. Baseline heart rate was lower in control subjects than in patients, increased with tilt in both groups, and remained lower in the control subjects throughout the experiment. Baseline systolic and diastolic blood pressure was similar in both groups. Diastolic blood pressure initially increased with tilt in all subjects and decreased significantly thereafter in patients. Pulse pressure was lower in patients throughout the experiment. The heart rate power spectra displayed a higher baseline level of low frequency fluctuations in the control group. The high frequency fluctuations component was similar in all subjects. The results of the test, regarding haemodynamic parameters and autonomic control of the heart rate, as expressed by low and high frequency fluctuations, are consistent with a reduced sympathetic reserve in the individuals with previous episodes of syncope.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01829016
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Failure of erythropoietin treatment in a case with primary autonomic failure (1997)
    Springer
    Clinical autonomic research 7 (1997), S. 333-336 
    Details
    ISSN: 1619-1560
    Keywords: erythropoietin ; autonomic failure ; heart rate variability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Previous studies have reported that anemia is a frequent occurence in patients with severe autonomic failure, that it can be corrected by exogenous erythropoietin and that upright blood pressure improves while on erythropoietin. The objective of this study was to determine the alteration of autonomic control during erythropoietin therapy in a patient with severe autonomic failure and severe symptomatic orthostatic hypotension, evaluated by spectral analysis of heart rate variability. The autonomic response to standing was evaluated before, after 1 month and after 6 months of erythropoietin therapy. The results were compared to an age- and sex-matched control adult. There was no improvement in the orthostatic hypotension during and at the end of the erythropoietin treatment despite an increase in hemoglobin from 9.6 g/dl before treatment to 12.5 g/dl during treatment. The spectral estimates of heart rate variability displayed a low variability at baseline, a paradoxical vagal enhancement and a lack of sympathetic increase on standing (before, during and at the end of the treatment). There was no improvement of baseline activity, nor of the response to standing during and at the end of the treatment with erythropoietin. We conclude that erythropoietin did not improve the autonomic response to standing, although it corrected anemia. Erythropoietin did not alter sympathetic activity, as reflected in the low frequency content of the power spectrum of heart rate fluctuations during and at the end of treatment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02267727
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Superconductivity and lattice dynamics of granular tin (1974)
    Springer
    Journal of low temperature physics 17 (1974), S. 375-383 
    Details
    ISSN: 1573-7357
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The superconducting transition temperature was measured in samples of 45-Å Sn grains embedded in a tin oxide matrix. The Debye temperature of the same samples was measured by the Mössbauer effect in119Sn in order to detect possible changes in the phonon spectrum. It was found thatT c is enhanced by 10% and γ is decreased by 4% relative to the bulk. Both trends are found to fit quantitatively with McMillan's theory of strong-coupling superconductors. The microstructure and the chemical composition of the samples were thoroughly studied by electron microscopy and the Mössbauer hyperfine interaction. Several conclusions were derived on the nature of the grains and their interaction with the dielectric coating.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00659081
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...