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Biomedical subjects

T Krause

Publications and source records attributed to T Krause.

At least 55 records · Page 3Linked to original sources
PubMed1998

Impaired cardiac uptake of meta-[123I]iodobenzylguanidine in Parkinson's disease with autonomic failure.

OBJECTIVE: To selectively investigate postganglionic sympathetic cardiac neurons in patients with Parkinson's disease and autonomic failure. MATERIAL AND METHODS: Metaiodobenzylguanidine (MIBG) is a pharmacologically inactive analogue of noradrenaline, which is similarly metabolized in noradrenergic neurons. Therefore the uptake of radiolabelled MIBG represents not only the localization of postganglionic sympathetic neurons but also their functional integrity. Ten patients with Parkinson's disease and autonomic failure underwent standardized autonomic testing, assessment of catecholamine plasma levels and scintigraphy with [123I]MIBG. RESULTS: The cardiac uptake of MIBG, as demonstrated by the heart/mediastinum ratio, was significantly lower in patients in comparison with controls. Scintigraphy with MIBG allowed the selective in-vivo investigation of postganglionic sympathetic cardiac efferents in patients with autonomic failure, a procedure which was previously confined to post-mortem examination. CONCLUSION: These findings point to a relevant postganglionic pattern of involvement of the autonomic nervous system (ANS) in Parkinson's disease and autonomic failure.

3-Iodobenzylguanidine↗
PubMed1998

Cerebral perfusion during transient global amnesia: findings with HMPAO SPECT.

UNLABELLED: The aim of this study was to investigate the pattern of regional cerebral blood flow changes associated with transient global amnesia (TGA). METHODS: HMPAO SPECT was performed in six consecutive patients during the acute phase of TGA. A follow-up SPECT was performed 3-20 wk later in four of the six patients. Semiquantitative analysis of 14 regions of interest, including the basal ganglia and the basal section of the temporal lobes, was performed by comparing patient data with control data obtained from a matched group of healthy subjects. RESULTS: During TGA, unilateral or bilateral hypoperfusion of the temporo-basal region was observed in four patients. Variable hypoperfusion of further cortical areas was observed in five patients. Two patients who exhibited the most marked cortical hypoperfusion also showed striatal and thalamic hypoperfusion. These changes were normalized in the control studies obtained in four patients. CONCLUSION: It remains unclear whether hypoperfusion during TGA represents a primary feature or a sequel of regional brain hypometabolism. Because hypoperfusion is not confined to the temporo-basal region or to the territory of the posterior cerebral artery, it is suggested that the origin of TGA-related changes lies at the level of subcortical structures that project diffusely to the cerebral cortex.

Acute Disease↗
PubMed1998

Analysis of lymphatic drainage in various forms of leg edema using two compartment lymphoscintigraphy.

The anatomical and functional status of the epifascial and subfascial lymphatic compartments was analyzed using two compartment lymphoscintigraphy in five groups of patients (total 55) with various forms of edema of the lower extremities. Digital whole body scintigraphy enabled semiquantitative estimation of radiotracer transport with comparison of lymphatic drainage between those individuals without (normal) and those with leg edema by calculating the uptake of the radiopharmaceutical transported to regional lymph nodes. A visual assessment of the lymphatic drainage pathways of the legs was also performed. In patients with cyclic idiopathic edema, an accelerated rate of lymphatic transport was detected (high lymph volume overload or dynamic insufficiency). In those with venous (phlebo) edemas, high volume lymphatic overload (dynamic insufficiency) of the epifascial compartment was scintigraphically detected by increased tracer uptake in regional nodes. In patients with deep femoral venous occlusion (post-thrombotic syndrome). subfascial lymphatic transport was uniformly markedly reduced (safety valve lymphatic insufficiency). On the other hand, in the epifascial compartment, lymph transport was accelerated. In those patients with recurrent or extensive skin ulceration, lymph transport was reduced. Patients with lipedema (obesity) scintigraphically showed no alteration in lymphatic transport. This study demonstrates that lymphatic drainage is notably affected (except in obesity termed lipedema) in various edemas of the leg. Lymphatic drainage varied depending on the specific compartment and the pathophysiologic mechanism accounting for the edema. Two compartment lymphoscintigraphy is a valuable diagnostic tool for accurate assessment of leg edema of known and unknown origin.

Adult↗
PubMed1997

Cardiac angiotensin II receptors: studies on functional coupling in Sprague-Dawley rats and TGR(alphaMHC-hAT1) transgenic rats.

The renin-angiotensin system plays an important role in the pathogenesis of cardiac hypertrophy and chronic heart failure as angiotensin II has been shown to induce cardiac hypertrophy and fibrosis. Besides these structural alterations, functional effects on cardiomyocytes have been reported in different mammalian species. Angiotensin II is known to produce a positive inotropic effect in some species, and differences in atrial and ventricular myocardium have been described. So far, the molecular events which govern angiotensin II-mediated changes in cardiac contractility are not completely understood. In order to study the dependency of the angiotensin II-induced positive inotropic effect on receptor density, we examined the effect of angiotensin II on cardiac function in atria, papillary muscles and isolated ventricular cardiomyocytes from adult Sprague-Dawley rats and TGR(alphaMHC-hAT1) transgenic rats, which expressed the human angiotensin AT1 receptor (hAT1) specifically in the heart. In atrial myocardium from adult Sprague-Dawley rats, angiotensin II (30 micromol/l) produced an AT1-mediated positive inotropic effect (38.5% of control), whereas in papillary muscles and isolated ventricular myocytes, no inotropic response was observed. As shown by polymerase chain reaction (PCR) and radioligand binding, the human angiotensin AT1 receptor was exclusively expressed in transgenic animals, which markedly overexpressed the angiotensin AT1 receptor. However, in transgenic rats the positive inotropic effect in atrial preparations was similar to the controls, and neither in papillary muscles nor in isolated cardiomyocytes the increase in receptor density led to an inotropic effect induced by angiotensin II. These data suggest that the existence of functionally uncoupled receptors rather than the low density of receptors at the ventricular site is responsible for the inability of ventricular myocardium to respond to angiotensin II.

1-Sarcosine-8-Isoleucine Angiotensin II↗
PubMed1997

[Involvement of the lymphatic system in primary non-lymphogenic edema of the leg. Studies with 2-compartment lymphoscintigraphy].

Two-compartment lymphoscintigraphy was developed to examine the sub- and epifascial lymphatics of the leg. Digital images were evaluated visually and semiquantitatively by calculating the uptake of activity within the lymph nodes. The data from patient groups with four different types of leg edema were compared with those of the control group to prove the involvement of the lymphatics in the non-lymphatic edema. The cyclic idiopathic edema demonstrated an accelerated transport of the lymph consistent with a high volume insufficiency. In phlebedema the high volume insufficiency was epifascially so distinct, that it could be detected scintigraphically. In post thrombotic syndrome the transport of the lymph was reduced dramatically corresponding to a safety valve insufficiency. Epifascially however, an accelerated lymph flow was observed due to compensatory mechanisms. The lipedema did not show any scintigraphic abnormalities. These results show that two-compartment lymphoscintigraphy can detect alterations in lymphatic function secondary to non-lymphogenic leg edema. The lymphatic function is changed according to the underlying pathophysiology which may be facilitate the differential diagnosis of such a leg edema.

Adult↗
PubMed1997

Administration of sufentanil and nitrous oxide blunts cardiovascular effects of desflurane but does not prevent an increase in middle cerebral artery blood flow velocity.

Desflurane has been reported to cause tachycardia and hypertension during induction of anaesthesia. The aim of this study was to determine the effects of desflurane on cerebral blood flow (CBF) velocity using transcranial Doppler ultrasonography in a setting that closely resembled usual clinical practice. In two groups (n = 9 in each) ASA Grade I or II patients, anaesthesia was induced with etomidate and vecuronium intravenously (i.v.), sufentanil (0.3 microgram kg-1 i.v.) was added in the second group. Patients were ventilated by facemask for 2 min before desflurane was administered in steps of 0.5 MAC min-1 until 1.5 MAC was reached and maintained for 7 min. Haemodynamic variables and CBF velocity in the middle cerebral artery (MCA) were monitored throughout the study period. In group 1 heart rate increased to 108 +/- 2 b.p.m. (37% increase) whereas MAP increased to 114 +/- 6 mmHg after administration of desflurane (33% increase). CBF velocity increased to 86 +/- 7 cm s-1 (69% increase). In group 2 no significant changes in systemic haemodynamic responses were measured after desflurane administration; however, CBF velocity increased to 73 +/- 5 cm s-1 (59% increase). The results indicate that desflurane increases CBF velocity concurrently with induction of tachycardia and hypertension. Although sufentanil and N2O attenuate the systemic haemodynamic alterations caused by desflurane, the CBF velocity increases. These data suggest that the abrupt addition of desflurane may have adverse consequences in patients at risk for intracranial hypertension.

Abdomen↗
PubMed1997

Transjugular intrahepatic portosystemic shunt (TIPS). Thrombogenicity in stents and its effect on shunt patency.

PURPOSE: To compare the thrombogenicity and patency of the Palmaz stent and the Wallstent, and to evaluate the effect of periprocedural heparin therapy in cirrhotic patients with maintained coagulation capacity who receive a transjugular intrahepatic portosystemic shunt (TIPS). MATERIAL AND METHODS: Twenty-four patients were randomized into 4 groups of 6 patients. Each received a Palmaz-stent or Wallstent TIPS with or without periprocedural heparin therapy. The groups receiving periprocedural heparin were given 24 U/kg b.w. just before stent placement, followed by 24 h therapeutic i.v. heparin. After 24 hours, all patients received i.v. heparin for 1 week followed by subcutaneous treatment with low-molecular-weight heparin (0.3 ml/day) for another 4 weeks. Stent thrombogenicity was determined scintigraphically after i.v. injection of 120-290 mBq of 99mTc-labeled platelets at the time of stent placement and expressed as the stent/heart ratio. Shunt patency was assessed by duplex sonography and confirmed radiologically. RESULTS: The aggregation ratio was highest 90 min after stent implantation. Wallstents showed a significantly higher ratio than Palmaz stents. Heparin reduced the ratio in patients with a Wallstent (-41%) but had no effect on Palmaz stents. Patients with a Wallstent without heparin had a higher rate of early shunt insufficiency (66.6%) than the other patients (0-16.6%). Primary assisted long-term patency was similar in the 4 groups. CONCLUSION: Wallstents were more thrombogenic than Palmaz stents and gave a significantly higher risk of early shunt insufficiency in cirrhotic patients with maintained coagulation capacity. Periprocedural heparin was effective in the prevention of shunt insufficiency and is therefore indicated in such patients.

Anticoagulants↗
PubMed1997

Inositol 1,4,5-trisphosphate in blood and skeletal muscle in human malignant hyperthermia.

The in vitro contracture test (IVCT) is the only available diagnostic method at present for evaluation of malignant hyperthermia (MH) susceptibility. However, the disadvantage of the IVCT is that it is invasive. Several studies suggest that an altered inositol phosphate system is involved in the development of MH. A greater concentration of inositol 1,4,5-trisphosphate (1,4,5-IP3) was found in MH susceptible (MHS) than in normal (MHN) skeletal muscles. In this study the concentrations of 1,4,5-IP3 in blood samples and skeletal muscle specimens of identical patients were measured in an attempt to define susceptibility to MH. Muscle biopsies were obtained from 34 patients with clinical suspicion of MH. Patients were first classified as MHS (n = 19), MHN (n = 8) or MH equivocal (MHE; n = 7) by the standard IVCT. For detection of 1,4,5-IP3 concentrations, blood samples were obtained and an additional muscle specimen was excised. After sample preparation, concentrations of 1,4,5-IP3 were measured using radioimmunoassay. In blood samples, concentrations of 1,4,5-IP3 were similar in all individuals tested for MH susceptibility and in control patients not tested for MH susceptibility (n = 44). In skeletal muscle, 1,4,5-IP3 concentrations were significantly higher in MHS than in MHE or MHN patients, respectively. Each MHS sample contained more 1,4,5-IP3 than the highest concentration measured in MHN muscle. Defining arbitrary thresholds for 1,4,5-IP3 concentration in skeletal muscles in order to discriminate between MHS and MHN status, it was possible to assign three MHE patients to MHS and four to MHN. This study supports the hypothesis that an altered inositol phosphate system might be involved in MH. However, measurement of 1,4,5-IP3 concentration in a simple blood sample preparation is not reliable for MH susceptibility screening.

Adolescent↗
PubMed1997

Prognostic significance of right ventricular afterload stress detected by echocardiography in patients with clinically suspected pulmonary embolism.

OBJECTIVE: To investigate the prognostic value of echocardiographic findings in patients who present with symptoms suggestive of acute pulmonary embolism. DESIGN: 317 patients with clinically suspected pulmonary embolism were prospectively evaluated by echocardiography for the presence of right ventricular afterload stress and right heart or pulmonary artery thrombi. Objective confirmation of pulmonary embolism by lung scan or pulmonary angiography was obtained in 164 (52%). The presence of deep venous thrombosis was established in 90 of 158 patients (57%) who underwent phlebographic or Doppler sonographic studies. RESULTS: Right ventricular afterload stress was diagnosed in 87 patients (27%). Objective confirmation of pulmonary embolism and diagnosis of deep venous thrombosis was more common in patients with right ventricular afterload stress than in those without (83% v 40% and 46% v 22%, respectively; P < 0.001). This was also true for the detection of thrombi in the right heart and major pulmonary arteries (12 patients v 1 patient; P < 0.001) as well as for the in-hospital mortality from venous thromboembolism (13% v 0.9%; P < 0.001). One year mortality from pulmonary embolism was 13% in patients with right ventricular afterload stress at presentation compared with 1.3% in those without (P < 0.001). CONCLUSIONS: The presence of right ventricular afterload stress detected by echocardiography is a major determinant of short term prognosis in patients with clinically suspected acute pulmonary embolism.

Acute Disease↗
PubMed1997

Immunoscintigraphy with anti-225.28S for ocular melanoma--a comparison with histology and immunohistochemistry.

AIM: The purpose of this prospective study was to evaluate the value of immunoscintigraphy (ISG) with anti-225.28S in clinically suspected ocular melanoma. METHODS: For this purpose standardized ISG was performed in 36 patients using both planar acquisition and emission computed tomography (ECT). Ocular melanoma was present in 31 patients. In 21 patients therapy was enucleation of the eye. These specimens were evaluated by histology and immunohistochemistry in 11 of 21 patients. RESULTS: Regarding the clinical diagnosis, ISG was positive only in 15 of 31 patients with ocular melanoma, regarding histology in 11 of 21 and regarding immunohistochemistry in 5 of 6 patients with a positive immunoreaction 5 patients showed no immunoreactivity, their ISG was negative. CONCLUSION: Thus a good correlation between ISG and immunohistochemistry was observed. However ISG using the cutaneous melanoma antibody 225.28S cannot be recommended for the diagnostic work-up of an ocular melanoma considering the poor immunoreactivity.

Adult↗
PubMed1996

[Correlation between endometriosis and fallopian tube patency in sterility patients especially after microsurgical sterility operations].

In 130 sterile women undergoing first look laparoscopy we found in 86.9% patent tubes. In this group in 34.5% an endometriosis was discovered. All patients with closed tubes had no signs of endometriosis. In a second look laparoscopy we found in 50% an endometriosis after microsurgery if the tubes were open. In this group we didn't also find an endometriosis if the tubes were closed. The frequency of endometriosis in women with laparoscopic sterilisation is 3.3%. After microsurgery in sterile women a second look laparoscopy seems to be very necessary to check the operation success and to exclude an endometriosis.

Adult↗
PubMed1996

Magnetic resonance imaging (MRI) for detection of active sacroiliitis--a prospective study comparing conventional radiography, scintigraphy, and contrast enhanced MRI.

OBJECTIVE: Sacroiliitis is often difficult to diagnose in the absence of radiographic alterations. For the diagnosis of active sacroiliitis, plain radiography, scintigraphy, and contrast enhanced magnetic resonance imaging (MRI) were evaluated in a prospective study. METHODS: In 44 consecutive patients with complete clinical and laboratory evaluation, plain radiographs, quantitative sacroiliac (SI) scintigraphy, and MRI were performed to evaluate the contribution of these imaging techniques to the diagnosis of active sacroiliitis. Scintiscanning and MRI were done in 20 control subjects to define the normal range of imaging findings. We determined the sensitivity and specificity for each imaging method using a reference standard based on clinical symptoms of inflammatory low back pain with or without laboratory signs, and on clinical and radiographic followup during 1.5-2.5 years to confirm diagnosis. RESULTS: MRI was most sensitive (95%) and superior to quantitative SI scintigraphy (48%) or conventional radiography (19%) for the detection and confirmation of active sacroiliitis. For the assessment of inflammatory signs, MRI had higher specificity (100%) than scintigraphy (97%) or plain radiography (47%). At repeat MRI after 2-30 months, there was persistent pathologic signal intensity in the subchondral bone area despite clinically successful antiinflammatory drug therapy. CONCLUSION: For the assessment of active changes in the synovial portion and the subchondral bone marrow, contrast enhanced MRI is superior to quantitative SI scintigraphy or conventional radiography. MRI picks up an additional 75% of early cases not diagnosed by plain radiography. Scintigraphy is only of limited value. Persistent pathologic signal intensity in the subchondral bone marrow seems to be closely associated with previous inflammatory episodes, thus limiting specificity of MRI for active sacroiliitis. Based on our findings we suggest an algorithm for the evaluation of patients with suspected active sacroiliitis.

Adolescent↗
PubMed1995

Heterologous complementation of peroxisome function in yeast: the Saccharomyces cerevisiae PAS3 gene restores peroxisome biogenesis in a Hansenula polymorpha per9 disruption mutant.

PER genes are essential for the biogenesis of peroxisomes in the yeast Hansenula polymorpha. Here we describe the functional complementation of a H. polymorpha per9 disruption strain (delta per9) by a heterologous gene. The Saccharomyces cerevisiae Pas3p, a homologue of per9p, restored peroxisome biogenesis and peroxisomal protein import in the delta per9 mutant, allowing it to grow again on methanol as sole carbon and energy source. This result shows that heterologous complementation of peroxisome function in yeast is indeed feasible and furthermore suggests that H. polymorpha delta per9 may be the candidate of choice to attempt the isolation of Per9p homologues from higher eukaryotes by functional complementation.

ATP-Binding Cassette Transporters↗
PubMed1995

Impaired endothelium-dependent vasodilation of coronary resistance vessels is associated with exercise-induced myocardial ischemia.

BACKGROUND: The release of endothelium-derived relaxing factors has been shown experimentally to be of pivotal importance for the maintenance of coronary blood flow during increased demand. In humans with coronary atherosclerosis, endothelial vasodilator dysfunction is not confined only to epicardial conductance vessels but may also extend into the coronary microcirculation. We therefore tested the hypothesis that endothelial vasodilator dysfunction of the coronary resistance vasculature is associated with myocardial ischemia during exercise in patients without hemodynamically significant epicardial artery stenoses. METHODS AND RESULTS: Coronary vasodilator function was assessed by subselective infusion of the endothelium-dependent dilator acetylcholine (0.036 to 3.6 micrograms/mL) and the endothelium-independent dilator papaverine (7 mg). Coronary blood flow responses were evaluated by intracoronary Doppler flow velocity recordings and quantitative angiography. Exercise-induced myocardial perfusion was determined by 201Tl single photon emission computed tomographic imaging. Thirteen patients had exercise-induced myocardial perfusion defects suggestive of myocardial ischemia, whereas 14 patients had normal thallium imaging during exercise. In patients with exercise-induced thallium perfusion defects, coronary blood flow responses to acetylcholine were significantly (P < .005) blunted compared with patients with normal thallium imaging during exercise. In contrast, coronary blood flow reserve to the endothelium-independent smooth muscle relaxant papaverine was similar in the two groups. Patients with exercise-induced thallium perfusion defects exhibited a significantly (P < .005) reduced (23.9 +/- 9.0% [mean +/- SD]) endothelium-mediated coronary vasodilator capacity compared with patients with normal thallium testing (56.2 +/- 27.8%). Epicardial artery vasoreactivity to acetylcholine did not differ between the two groups. CONCLUSIONS: Impaired endothelium-dependent vasodilation of the coronary microcirculation is associated with exercise-induced myocardial ischemia in patients without hemodynamically significant epicardial artery lesions. Endothelial vasodilator dysfunction extending into the coronary microcirculation may thus contribute to the ischemic manifestations of coronary artery disease during times of increased myocardial demand.

Acetylcholine↗
PubMed1995

Prevalence, characteristics, and risk stratification of electrocardiographic and symptomatic silence of myocardial ischemia despite scintigraphically evidenced ischemia in symptomatic patients presenting with severe coronary artery stenosis.

Symptoms of angina pectoris and transient ST-segment depression are most commonly used to evidence acute myocardial ischemia during exercise testing. However, the diagnostic accuracy of either or both criteria in relation to clinical characteristics and the patient's exercise response has been a subject of controversy. The prevalence and severity of symptoms of angina pectoris and/or ST-segment depression were studied prospectively in 147 consecutive patients with a history of daily angina pectoris, scintigraphic evidence of exercise-induced myocardial ischemia, and coronary artery stenosis > 75%. Logistic regression analysis was applied to determine absence of any or both criteria by the clinical characteristics or exercise response of the patient. During exercise testing, ST-segment response failed to prove scintigraphically evidenced myocardial ischemia in 14/147 patients (10%) and 35/147 patients (24%) when ST-segment depression > or = 0.1 in either > or = 1 or > or = 2 ECG leads was chosen. Symptoms of angina pectoris were found to be absent in 69/147 patients (47%). Only 58 patients (40%) suffered from angina and met the ECG criterion at the time of scintigraphic myocardial ischemia. Absence of ST-segment depression was best predicted by clinical variables such as large myocardial infarction (increase: 2.6 times, p = 0.007), number of stenoses < or = 2 (2.0 times, p = 0.023), and presence of diabetes mellitus (4.3 times, p = 0.035). Painless myocardial ischemia was determined by blood response to exercising. Thus, a double product > 23 increased the risk of painless myocardial ischemia by 1.5 times (p = 0.017).(ABSTRACT TRUNCATED AT 250 WORDS)

Angina Pectoris↗
PubMed1995

Reproducibility of basal and induced DNA single-strand breaks detected by the single-cell gel electrophoresis assay in human peripheral mononuclear leukocytes.

The aim of the reported study was to investigate the reproducibility of the single-cell gel electrophoresis (SCGE) assay in the determination of DNA single-strand breaks (SSBs) and to estimate the statistical requirements when the SCGE assay is used for the detection of genotoxicity in humans. In human peripheral mononuclear leukocytes (PMLs), we repeatedly measured the rate of SSBs after in vitro incubation of cells for 1 h at 4 degrees C in phosphate buffered saline (PBS, basal) or 10 microM or 50 microM H2O2 (induced). Intra-assay variation was determined from cryopreserved PMLs of a single donor. To assess intrasubject and intersubject variation, PMLs of ten healthy, nonsmoking subjects (aged 19-37 years) were tested 5-9 times. Cryopreserved cells revealed a mean coefficient of variation of 18% (PBS) and 7%-9% (H2O2). There were statistically significant differences between individuals in the rate of SSBs after incubation in PBS (P < 0.01), 10 microM H2O2 (P < 0.001), and 50 microM H2O2 (P < 0.001). The range of interindividual variability was 26% for basal and 12%-13% for induced SSBs, and the coefficient of intraindividual variation was 18%-72% (PBS) and 7%-23% (H2O2). Neither basal nor induced rates of DNA damage were related to gender or age. Estimates of the minimum detectable effects were based on these observed sources of variability (power 90%, level of significance 5%, assumed sample size 50). With two different groups, a difference of 31% in basal SSBs or 12% in induced SSBs would be detectable. Repeated measurement within one group could detect a difference of 26% in basal and 9% in induced SSBs. In summary, the SCGE assay appears to be suitable for the detection of single-strand breaks, e.g., in biomonitoring or environmental medicine, and the statistical requirements could be derived from our analysis of the sources of variability.

Adult↗