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Biomedical subjects

A Neugebauer

Publications and source records attributed to A Neugebauer.

At least 55 records · Page 3Linked to original sources
PubMed1995

Brain RNA synthesis, long-term potentiation and depression at the perforant path-granule cell synapse in the guinea pig.

The effects of long-term changes in synaptic efficacy at the perforant path-granule cell synapse on the de-novo synthesis of ribonucleic acid (RNA) were investigated in hippocampal and cortical areas in anaesthetized Guinea pig preparations. Two experiments were run with stimulating and recording microelectrodes aimed at the perforant bundle and dentate gyrus hilus on both sides. In Experiment 1, a low-frequency (LFS; 0.02 Hz, 3 h) or high-frequency stimulation (HFS; 400 Hz, 250 ms) was delivered to the left perforant bundle with the contralateral side as control. In Experiment 2, animals received LFS or HFS trains with implanted nonstimulated animals used as controls. The latency and amplitude of the field postsynaptic potentials (FPSP) and population spike (POPS) were monitored under baseline conditions and following stimulation over a 3 h period. In addition, two HFS groups were tested with few (HFS-F: every 15 min) or several test stimuli (HFS-S: every 3 min). In both experiments RNA synthesis was determined by measuring the amount of 3H-5,6-uridine incorporated into the RNA 3 h after bilateral intraventricular injection. In Exp. 1 the LFS group showed a higher synthesis of RNA than both HFS groups. The rate of RNA synthesis did not differ between the stimulated and nonstimulated side. In Exp. 2 the HFS groups showed a decreased RNA synthesis. In the HFS-F group, it pertained to the dorsal dentate area, CA1, subiculum, cingulate and dorsal cortices bilaterally, and to the ventral dentate area and CA3 on the nonstimulated side. In contrast, the HFS-S group showed decreased RNA synthesis at the dorsal dentate area and dorsal cortex on the stimulated side, and at CA1, subiculum, and cingulate cortex bilaterally. The decrease was stronger in the HFS-F than in the HFS-S group. Moreover, the subgroup with a low (0-60%) and that with a high (61-240%) level of long-term potentiation of FPSP revealed lower and higher RNA synthesis, respectively, both in homosynaptic target areas, and in heterosynaptic sites. Further, correlative analyses between FPSP, POPS and RNA synthesis revealed a complex pattern, depending upon the type of stimulation and on the brain side. Finally, cross-correlation analyses revealed a high degree of coupling among brain sites in the stimulated groups, indicating distributed covariant changes in RNA synthesis across different brain sites. Thus, changes in synaptic efficacy covary with changes in RNA synthesis, and presumably exert a modulatory role on gene expression.

Analysis of Variance↗
PubMed1992

Asthenopia: frequency and objective findings.

Fifty young adults were interviewed about the asthenopic symptoms experienced in the preceding 6 months by means of a questionnaire; they then underwent ophthalmic investigation. We established the frequency of occurrence of single asthenopic symptoms and looked for their prevalence in subgroups determined by objective findings such as phorias, different accommodation widths, different fusional vergence widths, and others. The frequencies of single complaints were: headache 42/50 (84%), ocular pain 17/50 (34%), foreign body sensation 25/50 (50%), red eyes 22/50 (44%), photophobia 24/50 (48%), double vision 5/50 (10%), difficulties when changing fixation distance 21/50 (42%). We did not find any obvious preference for one of the symptoms in any of the subgroups mentioned above.

Adult↗
PubMed1992

[Densitometry determination of coronary flow rates using digital subtraction angiography (DSA). Methods, multiple examinations and interobserver comparison].

In invasive diagnostics of coronary heart disease (CHD), three each DSA examinations of the left coronary artery were performed at 2-minute intervals in ten patients subsequent to conventional examination by means of a left-side cardiac catheter and coronary angiography. While placing the patient in left anterior oblique (60 degrees) position, 6 ml each of ionic contrast medium were injected mechanically with a flow of 4 ml/sec at a pacemaker-induced heart rate of 100/min. Examinations were performed according to a standard mode and were evaluated via the image analysing computer APU of the Philips DVI-DSA system. The purpose of this approach was to analyse the examination conditions and a new improved evaluation algorithm in respect of stability, feasibility and sensitivity. 17 series were evaluated by two examiners who were independent of each other. The interobserver differences obtained were between 5% at the time of maximum density (Tmax) and 25% with exponential downward slope of the curve (lambda), with reference to the median value in each case. Scatter of the individual examinations around the median value of all the three DSA runs is 11 to 17% with the exception of lambda. A significant rise can be proven in the RCX region for the curve slope rise parameters "slope" and "RFL2". We interpret this as a genuine 1.2 to 1.3 fold regional flow increase due to the residual effect of the contrast medium. At the same time, this can be interpreted as an indicator for the good sensitivity of the method.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Distributed changes in rat brain DNA synthesis with long-term habituation and potentiation of the perforant path-granule cell synapse.

The involvement of brain deoxyribonucleic acid (DNA) synthesis in adaptive neural events was studied in the adult rat during long-term habituation (LTH) or potentiation (LTP) of the perforant path-granule cell synapse. Male Long-Evans rats were given 50 muCi [3H]thymidine intraventricularly under urethane anesthesia. Soon thereafter, field excitatory postsynaptic potential (EPSP) slope and population spike were monitored from the right dentate gyrus before and at various times (5, 10, 15, 60 min) following the delivery to the ipsilateral perforant bundle of a low frequency (LFS: 1.0 Hz, 160 s) or a high-frequency train (HFS: 400 Hz, 200 ms), repeated once after 5 min. Unstimulated implanted rats served as controls. DNA synthesis was evaluated by the incorporation of the radioactive precursor into DNA of several brain areas at the end of a 1 h incorporation period. In CA1, LTH and LTP increased DNA synthesis by 30% on the stimulated side. In the entorhinal cortex, LTH but not LTP increased DNA synthesis (by 30%) on the stimulated side. Conversely, in the frontal cortex, LTP but not LTH increased DNA synthesis (by 100%) on both sides. Long-lasting changes in synaptic efficacy covaried non-linearly with DNA synthesis in mono- and polysynaptically stimulated hippocampal regions, and in functionally associated neocortical areas. The co-variations of population spike amplitude were positive for LTH and negative for LTP in the dentate gyrus and frontal cortex of both sides, and in CA3/CA1 of the stimulated side, indicating higher DNA synthesis at lower values of LTH and LTP, and viceversa. Further, regional cross-correlation analyses revealed a high degree of synchronization among brain sites, following low- or high-frequency train pulses, indicating that (i) extra-target sites participate on the stimulated and on the contralateral side, and (ii) small distributed changes take place across the sampled neural networks. A modulatory role of information flow on brain DNA synthesis is inferred to take place in a diffuse, distributed manner.

Animals↗
PubMed1991

[The oral health of an East German population of a large city. The basic research of the Dresden prevention study on 2500 16- to 35-year-olds].

Oral health behaviour, oral health state, dental care effectiveness and preventive-curative care needs were subject of a basic examination using 2500 randomly selected patients aged 16-35 years in 6 Dresden state health services in 1988. The spectrum of methods included extended anamnesis, plaque index according to Silness & Löe, DMF/T index and DMF/S index according to WHO criteria without X-ray diagnostics, GPM/T index, CPITN, as well as assessment of gingival recessions, acute and chronic trauma and the prosthetic status. Considering a mean DMF/T of 9.88, DMF/S of 17.93 and GPM/T of 11.9 in patients being 16-19 years and a DMF/T of 15.21, DMF/S of 40.94 and GPM/T of 12.9 in patients being 30-35 years, as well as the insufficient dental care, the majority of patients was in need of preventive care measures. Filling therapy and gingivitis treatment were necessary from the curative point of view. Early chronic tooth surface loss required early preventive-curative intervention. The key for an effective care in the early and middle adult age is a functioning individual concept with preventive emphasis which should include a basic and a risk strategy.

Adolescent↗
PubMed1990

[Myocardial tomography with single photon emission computerized tomography (SPECT) technique in X syndrome].

Compared with the usual planar scintigraphy of the myocardium the single photon emission computer tomography (SPECT) has essential advantages. By means of the SPECT a three-dimensional reconstruction of the intersection image is possible which allows a judgement of the myocardium in the transversal, sagittal and coronary planes of section. The scans of the SPECT are richer in contrast and freer from overshadowings of normally of disturbedly perfused areas of the myocardium. 43 patients with angina pectoris complaints in angiographically normal coronary arteries (syndrome X) were examined by means of the SPECT under bicycle ergometer load and at rest. As radionuclide thallium-201 was used. 28 out of 43 patients (65%) showed disturbances of the perfusion, in which cases 21 patients with reversible ischaemias and 7 ones with cicatrised changes and an ischaemia of the marginal zone were conspicuous. Previous own investigations with the planar Tl-201 scintigraphy of the myocardium showed pathological findings in 66% of the cases with a syndrome X. The nearly identical results speak for the high reliability of the scintigraphy of the myocardium, but against the increase sensitivity of the SPECT in contrast to the planar scintigraphy of the myocardium.

Angina Pectoris↗
PubMed1990

[A densitometric method for the assessment of myocardial perfusion using digital subtraction angiography].

The aim of the method presented is the quantitative description of the perfusion of the myocardium. In the framework of the invasive diagnostics of the coronary heart disease with catheterization of the left heart, ventriculography and coronarography in Seldinger's technique in 50 patients (35 of them well to be evaluated) subsequently DSA-investigations of the left coronary artery (LCA) were performed by means of the DVI-2 CV system (Philips) and densitometrically evaluated with the help of the analytic processing unit (APU). In injection by hand of 4 and 6 ml, respectively, visotrast 370 in each case 10-15 DSA-pictures in LAO 60 degrees-projection were possible. For a differentiated evaluation the total myocardium was subdivided into 12 partial areas. The densitometric analysis consisted in the calculation of time-density curves over all areas and their description by suitable parameters: density maximum (DMAX) and its moment TMAX, elevation of the curve SLOPE at 50% of DMAX, the elevation time AZEIT as well as measure for the exponential decrease of the curve after the maximum LAMBDA. For special questioning the parameters of the 12 areas were concentrated according to the main supply areas of the anterior interventricular branch (RIVA), the circumflex branch (RCX) and the apex of the heart, respectively. In the interobserver comparison the statistical analysis of the results showed deviations lower than 10% (except LAMBDA). Significant correlations were found between the body-weight and the applied quantity of contrast remedies, respectively, and the parameters DMAX and AZEIT.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

[Postoperative supraventricular arrhythmias in atrial septal defects].

Before operation as well as over a mean postoperative period of 8.9 years 222 adults with atrial septal defects underwent a follow-up examination concerning frequency and clinical significance of supraventricular dysrhythmias. Thereby disturbances of the formation of stimuli were found before the operative procedure in 60 patients and after the correction in 115 patients. Disturbances of the sinoatrial and atrioventricular conduction were registered preoperatively in 53 cases and postoperatively in 81 cases. Within these statistically significant increases in particular the significant forms of dysrhythmia elevated after the atrial septal defect closure. Thus the tachycardiac atrial dysrhythmias increased from 7 to 28%, complex arrhythmias even from 2 to 16%. Of dysrhythmias to be taken seriously patients with IAVC and supraventricular defect are significantly more frequently affected than those with interatrial septal defects. Size of the defect, shunt volume and pressure of the pulmonary artery did not show any connections with the frequency of dysrhythmia. On the other hand, when accompanying cardiac anomalies, symptoms of a manifest heart insufficiency were present and at an operation age over 40 years arrhythmias were proved more frequently. The complaints of the patients did not correlate with the endangering, but are imprinted by the haemodynamics and its postoperative normalization. By the established profile of complaints and a decrease of frequency from 76% pre- to only 40% postoperative the patient with atrial septal defect cannot estimate his individual risk and needs an adapted long-term concept for his cardiological care.

Adolescent↗
PubMed1990

[Venous digital subtraction angiography of the left ventricle in comparison with conventional angiography].

In 42 patients with coronary heart disease within a left heart catheterization by means of coronarography and conventional angiocardiography in each case before and after GTN digital subtraction angiographies of the left ventricle were performed with central venous injection of 20 ml visotrast with a flow of 16-18 ml/s. A DVI2-CV system of the firm Philips served as investigation device. In general between the angiocardiography and the digital subtraction angiographies the following results were obtained for EF 0.81, EDV 0.71, and ESV 0.88. When evaluating only the finally examined 22 patients the correlations improve for all parameters (EF: 0.89, EDV: 0.82, ESV: 0.90). Furthermore is was shown that the volumes are underestimated by 8-10%. The quantification of the regional movement of the wall according to the radial axis method did not results in any significant differences between the digital subtraction angiographies and the angiocardiography. The effects of GTN on the global and regional functional parameters appear somewhat more distinct in the digital subtraction angiographies than in the angiocardiography and are partly significant only in the first one. The influence of the experience of the investigator, the cardial state of the patient and other influential factors on the quality of the digital subtraction angiocardiographies are described and discussed. Therefore we regard the digital subtraction angiography as method of choice in indications to right heart catheterization without coronary angiography.

Adult↗
PubMed1988

[Determination of global left ventricular functional parameters with intraventricular digital subtraction angiography in coronary disease].

Left heart catheterisation, coronarography and conventional angiocardiography of the left ventricle (ACG) [30 degrees right anterior oblique; 45 ml contrast medium (Visotrast) with a flow of 12 ml per sec.] was performed in 86 patients with coronary heart disease. Additionally intraventricular digital subtraction angiography (DSA) was performed, using a Philips-device (DVI 2 CV). For DSA 15 ml contrast medium (Visotrast) was injected with a flow of 8 ml per sec. 73 examinations were selected for the study. The aim of the study was to compare the usefulness and applicability of ACG und DSA for ventriculography. There were no significant differences between enddiastolic (EDV) and endsystolic (ESV) volumes as well as ejection fractions (EF) determined by ACG and DSA. Results of the analysis of correlation were rEDV = 0.85;rESV = 0.93;rEF = 0.80. The increase of the end-diastolic pressure after ACG was determined with 7 Torr (mean), after DSA with less than 2 Torr (mean). According to these results we would prefer intraventricular DSA to conventional ACG, provided the technical equipment is available. This is concluded despite the fact that in single cases considerable differences were found between the volumes estimated by ACG and those determined by DSA. These differences were analysed in detail. The main advantages of the DSA are the by far smaller inconvenience for the patients, the rare occurrence of provoked extrasystoles and the fast and easy analysis of the ventriculographies by means of the implemented image processing programmes.

Cardiac Output↗
PubMed1986

[Modification of orocecal transit time of salazosulfapyridine by atropine and metoclopramide in healthy probands].

The first appearance of sulpharyridine in plasma was investigated in nine healthy informed male volunteers. In a three way crossover design 6 g salazopyrin alone, together with metoclopramide (0.3 mg/kg i.m.) or atropine (0.01 mg/kg i.m.) were given. Sulphapyridine appears in the blood at the (means +/- S means) 6.2 h +/- 0.8 h (range: 3-11 h) in controls. Together with metoclopramide the first appearance is 3.6 h +/- 0.7 h (range: 2-8 h) and together with atropine these values are 8.1 +/- 0.8 h (range: 6-12 h). The differences are significant with p less than 0.05. The results show the pharmacological modification of motility in the gastrointestinal tract and in consequence the usefulness of salazopyridine to determine the transit time.

Adult↗
PubMed1985

[Computer tomography diagnosis of cardiac and pericardial space-occupying lesions].

Cardial and paracardial space occupations need a rapid, possibly non-invasive diagnosis. The echocardiography and the computer tomography are practically available. At the instance of 17 intracardial space occupations (4 solid tumours and 13 thrombi), which were found in a total number of 600 cardio-computer-tomographies, and several selected peri- und paracardial space occupations the high diagnostic significance of the computer tomography is demonstrated. With the computer tomography a standardized method independent of the investigator is available which in qualitative respect appears of the same value as to echocardiography in the diagnostics of the intracardial space occupations and in the peri- and paracardial space occupations the non-invasive method is the method of choice.

Calcinosis↗
PubMed1984

[Side effects of anti-arrhythmia drugs].

Since there are no antiarrhythmic drugs with selective effect on the removal of pathologic rhythms without influence on the formation of normal stimuli and the conduction system, which are free from cardiac and extracardiac side effects, in the application of an antiarrhythmic drug apart from an indication which is strictly to be established it must equivalently be taken into consideration which systemic and genuine side effects, pharmacokinetic problems and drug interactions must be taken into account. An unavoidable risk (systemic side effects) is to be put up with. Existing contraindications sometimes bring about the renunciation of therapy. Side effects are avoidable, when they are strictly controlled, since they are then recognized in time and lead to the interruption of therapy.

Anti-Arrhythmia Agents↗
PubMed1984

[Computer tomographic evaluation of left ventricular kinetics].

The judgment of the function of the left ventricle is computer-tomographically possible using the ECG-regulated cardio-computer-tomography in a temporary resolution of about 0.1 sec. The qualitative and quantitative evaluation of the systolic and diastolic changes of the ventricle in patients with normal CT-findings, with idiopathic hypertrophic subaortic stenosis and with disturbances of motility in chronic ischaemic heart disease confirms the possible functional evidence known from literature. The quantitative parameters, in particular the systolic abbreviation of the axis, allow an estimation of the motility. The measurement of the thickness at the interventricular septum and at the lateral wall of the myocardium as well as the systolic abbreviation of the axis and the left-ventricular ejection fraction are essentially higher in the idiopathic hypertrophic subaortic stenosis than in the normal group. The values of the patients with disturbances of motility in the ischaemic heart disease were clearly below. The diagnosis of the idiopathic hypertrophic subaortic stenosis with response of the size of obstruction by the telesystolic and telediastolic pictures is possible in a high percentage. Sequelae of the chronic ischaemic heart disease, e.g. scars, become visible by a narrowing or an absence of the normal edge of the myocardium. Global and localized disturbances of motility are diagnosable by phase-referred systolic and diastolic ECG-regulated pictures.

Cardiac Output↗
PubMed1983

[The value of computer tomography in the postoperative long-term surveillance of patients with a vascular prosthesis for aorta replacement].

Because of the possibility of life-threatening late complications by anastomotic aneurysms and the danger of their rupture, all patients in whom a coarctation of the aorta was resected and replaced by a vascular prosthesis must be followed up continuously for life. Their chest x-rays show-in addition to unequivocally normal or pathological findings-sometimes questionable variations of the aortic outline, which must be diagnosed definitely by further investigations. By means of computerized tomography, the suspicion of an anastomotic aneurysm can either be refuted or confirmed in almost all cases. Thus, the invasive examination by aortography, which is desirable before operation of an aneurysm, may be omitted in the group of unsuspicious patients. Out of 198 patients, who received a vascular prosthesis for correction of an aortic coarctation in the time from 1960 to 1980, 27 were examined by computerized tomography because of irregular findings in their chest x-rays. In 6 patients the suspicion of an anastomotic aneurysm was confirmed and could be proved by aortography and reoperation. In 21 patients an aortography could be omitted because of its unsuspicious findings by computerized tomography.

Aorta, Thoracic↗
PubMed1983

[Diagnosis and therapy of supraventricular tachycardia].

In form of a survey is demonstrated which contributions make, apart from clinic and routine ECG, the storage ECG, the load ECG as well as special ECG derivation techniques, such as the oesophagus ECG, intracardiac ECG derivations with electrostimulation as well as the endocardiac mapping technique for the analysis of various forms of supraventricular tachycardias including the preexcitation syndromes. Also the discussion of medicamentous and electrotherapeutic methods is performed above all under the clinical aspects of applicability, in which cases the hierarchy and combination in therapy are dealt with.

Anti-Arrhythmia Agents↗