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Biomedical subjects

T Krause

Publications and source records attributed to T Krause.

At least 73 records · Page 4Linked to original sources
PubMed1995

Assessment of acute myocardial necrosis after cardiopulmonary resuscitation and cardioversion by means of combined thallium-201/technetium-99m pyrophosphate tomography.

Diagnosis of acute myocardial necrosis by means of conventional electrocardiographic criteria or the release of cardiac enzymes is often difficult or even impossible in patients with out-of-hospital cardiac arrest due to ventricular fibrillation with subsequent cardiopulmonary resuscitation including several DC countershocks. Simultaneous thallium-201/technetium-99m pyrophosphate (PYP) tomography was prospectively applied to 57 patients without typical clinical or electrocardiographic signs of acute myocardial infarction within 48 h after successful resuscitation from out-of-hospital cardiac arrest. Scintigraphic evidence of acute necrosis was present in 23/57 patients (40%). Increased 99mTc-PYP uptake in the pericardial tissue was found in 24 patients (42%). Maximal creatine kinase (CK) concentration was increased in 50/57 patients (88%). CK-MB activity averaged 68+/-52 U/l in patients with positive and 17+/-13 U/l in patients with negative tomograms (P<0.0005), demonstrating the validity of 201Tl/99mTc-PYP tomography. It may be concluded that simultaneous 201Tl/99mTc-PYP tomography is a valuable tool for evaluation of myocardial necrosis after cardiopulmonary resuscitation including DC countershock. Acute myocardial necrosis, as indicated by scintigraphy, represents a potential trigger for the occurrence of ventricular fibrillation. Therefore, 201Tl/99mTc-PYP tomography can be recommended in order to guide further diagnostic and therapeutic interventions in patients after cardiopulmonary resuscitation in whom the underlying cause of the occurrence of ventricular fibrillation is obscure.

Acute Disease↗
PubMed1995

Determination of low level exposure to volatile aromatic hydrocarbons and genotoxic effects in workers at a styrene plant.

OBJECTIVES: Low exposures to volatile aromatic hydrocarbons and cytogenetic effects in peripheral white blood cells were determined in 25 healthy workers employed in different areas of a styrene production plant in the former German Democratic Republic. The results were compared with 25 healthy unexposed controls (matched for age and sex) employed in the same company. METHODS: The concentrations of aromatic hydrocarbons determined from active air sampling in all areas of the factory (styrene: 73-3540 micrograms/m3 (< 0.01-0.83 ppm); ethylbenzene 365-2340 micrograms/m3 (0.08-0.53 ppm); benzene 73-3540 micrograms/m3 ( < 0.02-1.11 ppm); toluene 54-2960 micrograms/m3 (0.01-0.78 ppm); xylenes 12-94 micrograms/m3 ( < 0.01-0.02 ppm)) were considerably lower than in the pump house ( > 4000 micrograms/m3 styrene, ethylbenzene, benzene, and toluene; > 500 micrograms/m3 xylenes), which was only intermittently occupied for short periods. Passive personal monitoring, biomonitoring of exhaled air and metabolites (mandelic, phenylglyoxylic, trans, trans-muconic, hippuric, o-, m- and p-methylhippuric acids, and phenol) in urine samples collected before and after an eight hour working shift was used to assess individual exposure. Questionnaires and examination of company records showed that the historical exposure was far higher than that measured. Genotoxic monitoring was performed by nuclease P1-enhanced 32P-postlabelling of DNA adducts in peripheral blood monocytes, and DNA single strand breaks, sister chromatid exchange, and micronuclei in lymphocytes. The content of kinetochores in the micronuclei was determined by immunofluorescence with specific antibodies from the serum of CREST patients. RESULTS: No genotoxic effects related to exposure were detected by DNA adducts or DNA single strand breaks and sister chromatid exchange. The only effect related to exposure was an increase in kinetochore positive micronuclei in peripheral lymphocytes; the frequency of total micronuclei in peripheral lymphocytes did not change. Smoking was confirmed by measurement of plasma cotinine, and no confounding effect was found on any of the cytogenetic variables. CONCLUSIONS: Low occupational exposure to styrene, benzene, and ethylbenzene did not induce alterations of genotoxicological variables except kinetochore positive micronuclei. This is the first reported use of the CREST technique for an in vivo study in occupational toxicology, which thus could serve as a valuable and sensitive technique for toxicogenic monitoring.

Adult↗
PubMed1995

Improved dose concept for radioiodine therapy of multifocal and disseminated functional thyroid autonomy.

The present study analyzes the improvement of the outcome of radioidine therapy in non-immunogenic hyperthyroidism by adapting the target dose to the 99mTc-pertechnetate thyroid uptake under suppression (TcTUs) prior to radioiodine therapy. The TcTUs is a substitute for the non-suppressible iodine turnover. The 89 patients presented with a basal thyrotropin level of < 0.1 mU/l, normal values for free triiodothyronine and thyroxine and with multifocal or disseminated thyroid autonomy. These terms describe the scintigraphic distribution pattern of autonomous iodine turnover. Thirty-two patients had a TcTUs between 1.6 and 3.2% (group A) and 57 had a TcTUs > 3.2% (group B). Fifty-five patients (three of group A and 52 of group B) were treated previously for overt hyperthyroidism with antithyroid drugs. Target doses of 150 and 200 Gy were used in both groups and 300 Gy in group B only. Six months after radioiodine therapy, a basal TSH level of > or = 0.5 mU/l as criterion of therapy success was observed in 94% of group A and in 54% of group B. Further differentiation of group B shows an increasing success rate with the target dose used: 45% after 150 Gy, 50% after 200 Gy and 90% after 300 Gy. In patients with a basal TSH level of < 0.5 mU/l after radioiodine therapy, the TcTUs was evaluated again.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Effect of site-directed mutagenesis of conserved lysine residues upon Pas1 protein function in peroxisome biogenesis.

The Pas1 protein (Pas1p) is required for peroxisome biogenesis in Saccharomyces cerevisiae and contains two putative ATP-binding sites, each within a domain which is conserved among members of the recently characterized AAA-family. To elucidate whether both putative ATP-binding sites are essential for Pas1p function, lysine 467 of the first and lysine 744 of the second putative ATP-binding site were each changed to glutamate by site-directed mutagenesis. While replacement of lysine 744 abolished the function of the Pas1 protein in peroxisome biogenesis, replacement of lysine 467 had no obvious effect.

ATPases Associated with Diverse Cellular Activitie↗
PubMed1994

Determination of DNA single-strand breaks in lymphocytes of smokers and nonsmokers exposed to environmental tobacco smoke using the nick translation assay.

The detection of DNA single-strand breaks (SSB) in human mononucleated white blood cells (MWBC) using a modified version of the nick translation assay is presented. This assay allows rapid and sensitive examination of SSB using only 5 ml heparinized blood for an eightfold determination. The assay was standardized by incubation of MBWC in vitro with N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), a known genotoxic agent. In vitro incubation of MWBC with MNNG induced a dose-dependent increase in DNA-SSB at doses between 5 and 500 microM MNNG. The detection limit for the assay was 5 microM MNNG. To assess the suitability of this assay to detect SSB in vivo a controlled study was performed in which volunteer smokers (n = 5), nonsmokers (n = 5) exposed to environmental tobacco smoke (ETS), and nonsmokers controls (n = 5) were compared. The study lasted 4 experimental days, 2 control and 2 exposure days. On control days (days 1 and 3) smokers and nonsmokers sat in an unventilated 45 m3 room for 8 h. On the exposure days (days 2 and 4) each of the five smokers smoked 24 cigarettes in 8 h, while the five nonsmokers were exposed to the ETS generated by the smoking volunteers. High exposure to tobacco smoke was confirmed by dosimetry of carboxyhemoglobin (CO-Hb), plasma nicotine and cotinine levels. Blood was drawn before and after each exposure on all 4 experimental days for determination of DNA-SSB in lymphocytes immediately after isolation of blood cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

[The current status of nuclear cardiology].

Unlike other techniques, nuclear cardiologic imaging enables evaluation of cardiac function employing radioactive tracers. This procedure can be used to assess myocardial blood flow, metabolism, viability, cardiac innervation and receptor status. Therefore, this noninvasive imaging modality can be regarded as supplementary to the screening methods in cardiology and also to angiography. General clinical use was not possible until the rapid development of nuclear medicine in the fifties began. With increasing widespread of positron emission tomography more detailed information on metabolic tissue characterization can be expected and will be of enormous relevance in clinical decision making and in selecting patients for interventions.

Cardiomyopathies↗
PubMed1993

Comparison in acute myocardial infarction of anisoylated plasminogen streptokinase activator complex versus heparin evaluated by simultaneous thallium-201/technetium-99m pyrophosphate tomography.

In a subgroup of 45 patients with acute myocardial infarction (AMI) from the German multicenter trial of anisoylated plasminogen streptokinase activator complex (APSAC) (n = 20) versus heparin (n = 25), simultaneous thallium (TI)-201 technetium (Tc)-99m pyrophosphate (PYP) tomography was initiated to elucidate a possible benefit of APSAC over heparin. Findings in the 2 treatment groups were similar with respect to TI-201 defect score, relative scintigraphic infarct size, and in keeping with the main group coronary artery patency, global ejection fraction and maximal creatine kinase level. However, 2 different TI-201/Tc-99m PYP accumulation patterns within the area of infarction (homogeneous, group A; inhomogeneous, group B) were identified. Both treatment groups were similar with regard to the frequency of the homogeneous and inhomogeneous pattern. In comparing the 2 accumulation patterns, creatine kinase peaked earlier in group A than in group B, and global left ventricular ejection fraction was significantly higher in group A than in group B. In Group A, 30 of 31 patients and in group B 7 of 11 patients had a patent infarct-related vessel (p < 0.025). TI-201 defect score was lower in group A than in group B. Likewise, relative size of the infarction as determined from Tc-99m PYP images was significantly lower in group A than in group B. Fifteen patients experienced cardiogenic shock or severe heart failure. Patients in group B had a higher incidence of these in-hospital complications than patients in group A (92 vs 12%, p < 0.0005). Scintigraphic infarct size and TI-201 defect score were greater in patients with the aforementioned clinical events.(ABSTRACT TRUNCATED AT 250 WORDS)

Anistreplase↗
PubMed1993

A novel technique for the detection of DNA single-strand breaks in human white blood cells and its combination with the unscheduled DNA synthesis assay.

A modified assay for the detection of DNA single-strand breaks (SSBs) in human mononucleated white blood cells (MWBCs) based on the nick translation (NT) reaction was developed and combined with the test for unscheduled DNA synthesis (UDS). Both assays were performed on disposable 96-well filtration plates and therefore allowed rapid and sensitive examination of SSBs and UDS. Only 5-8 ml of heparinized blood is required for an eightfold determination in both assays. The uptake of radioactive nucleotide precursors was demonstrated to depend linearly upon the NT reaction time and in both assay systems on the number of investigated cells. The best results and the lowest signal to noise ratio were obtained when the NT assay was performed at 25 degrees C for 20 min. The test was standardized for 150,000 MWBCs/well and a polymerase I concentration of 20 U/ml. The same number of cells were used to measure UDS during a 4-h incubation at 37 degrees C. We observed a dose-dependent increase in SSBs after in vitro incubation with N-methyl-N-nitrosoguanidine (MNNG), with a detection limit of 50 microM when MNNG was present for 1 h and of 5 microM after 20-h incubation period. UDS in MWBCs was increased after treatment for 1 h with MNNG (200 microM) only if poly(ADP)ribose synthesis was inhibited by 3-aminobenzamide. UDS was induced by 320 microM methyl methanesulfonate, but SSBs could only be detected after inhibition of UDS by 100 microM hydroxyurea.(ABSTRACT TRUNCATED AT 250 WORDS)

Chromosome Aberrations↗
PubMed1993

Positive ventilation-perfusion lung scan and positive Tl-201 myocardial scintigraphy due to Takayasu's arteritis.

A case of Takayasu's arteritis is reported. Ventilation-perfusion lung scans and exercise thallium scintigraphy clearly showed pulmonary and coronary arterial involvement, respectively. Clinical examination and angiography revealed no other abnormal vascular findings. This case points out the difficulty in attempting to diagnose Takayasu's disease if only atypical vascular involvement is present.

Adult↗
PubMed1993

Effect of local low-dose thrombolysis on clinical outcome in acute embolic renal artery occlusion.

PURPOSE: To determine the utility of local thrombolysis in treatment of acute embolic renal artery occlusion. MATERIALS AND METHODS: Fourteen patients with acute embolic renal artery occlusion treated with local low-dose thrombolysis were studied. Diagnosis was made with renal scintigraphy and selective renal arteriography. RESULTS: Thrombolysis was successful in 13 of 14 patients. During 1-72 months of follow-up (mean, 27.1 months), renal function did not improve on the side of complete renal artery occlusion, whereas stabilization of renal function at the pretherapy level was seen in patients with incomplete obstruction of the renal artery or complete obstruction at the level of segmental branches. In none of the patients did renal function return to normal. CONCLUSION: In acute embolic renal artery occlusion, thrombolytic therapy does not restore renal function and is therefore not indicated once the ischemic tolerance of the kidney (approximately 90 minutes) has been exceeded.

Acute Kidney Injury↗
PubMed1993

The importance of the subfascial lymphatics in the diagnosis of lower limb edema: investigations with semiquantitative lymphoscintigraphy.

A new method of semiquantitative lymphoscintigraphy for the evaluation of lower limb edema is characterized by (1) the evaluation of both the epifascial and subfascial system in order to assess type and stage of the edema, (2) the use of high-resolution digital whole-body imaging to facilitate the calculation of functional parameters, and (3) the use of active, standardized ergometry for reproducibility. The appearance time of 99mTc-labeled human albumin nanocolloid in inguinal lymph nodes after injection and the percent uptake of colloid into lymph nodes at 40 and 120 min after injection served as functional parameters. Patients with edema of the lower limb were compared with normal subjects. In patients with primary lymphedema the two lymphatic compartments are functionally compromised. Early and advanced stages of postthrombotic syndromes can be distinguished by characteristic lymphoscintigraphic patterns in epifascial and subfascial lymphatic compartments. These results indicate that only the separate evaluation of both the epifascial and subfascial compartments allows an accurate functional assessment of the lymphatics in lower limb edema.

Adolescent↗
PubMed1993

Improved evaluation of technetium-99m-red blood cell SPECT in hemangioma of the liver.

This paper reports the results of a prospective study carried out to evaluate a new reading method of tomographic 99mTc red blood cell (RBC) imaging in liver hemangiomas. For this purpose, assessment of planar imaging and conventional, static 99mTc-RBC SPECT presentation (x-ray type film) (Method 1) was compared to a dynamic three-view display of SPECT slices (Method 2) in 21 patients with 56 hemangiomas and 18 patients with malignant liver lesions. Of the 56 hemangiomas, 47 were diagnosed by US, 6 by CT and 56 by MRI. Twenty-nine (52%) hemangiomas were detected by planar scintigraphy and 38 (68%) by SPECT Method 1, whereas 53 (95%) were visualized by SPECT Method 2. Comparing Methods 1 and 2 in hemangiomas < or = 1.0 cm, 1.1-2.0 cm and 2.1-3.0 cm in diameter, Method 2 improved sensitivity from 18% to 82%, 50% to 93% and 82% to 100%, respectively. The smallest hemangioma detected with Method 2 was 0.5 cm in diameter; with Method 1, 0.9 cm; and with planar imaging, 1.0 cm. As assessed by evaluation of the metastases and carcinomas, the specificity for hemangioma was 100%, independent of the method applied, resulting in a positive predictive value of 100%. This study suggests that evaluation of dynamically displayed 99mTc-RBC SPECT studies is superior to conventional reading of static display and comparable to MRI in liver hemangioma > or = 1 cm. Therefore, this approach is suggested as an alternative to MRI for confirming the diagnosis of liver hemangioma > or = 1 cm if planar imaging is negative. This option is available with most modern computer software systems and saves additional disbursement.

Adult↗
PubMed1992

Short- and long-term antiarrhythmic and hemodynamic effects of d,l-sotalol in patients with symptomatic ventricular arrhythmias.

The antiarrhythmic and hemodynamic effects of sotalol (160 to 480 mg/day), a beta-blocking agent that prolongs ventricular repolarization, were examined in 38 patients with complex symptomatic ventricular ectopic activity. During ambulatory monitoring, 24 patients (63%) exhibited a reduction of greater than 75% in single ventricular premature beats (VPBs) and greater than 90% reduction in repetitive arrhythmia. In contrast to the effects of other agents, left ventricular ejection fraction as determined by radionuclide angiography was not impaired, increasing slightly from 45 +/- 14% to 47 +/- 14% during therapy (p less than 0.05). Antiarrhythmic drug efficacy did not correlate with baseline ejection fraction or sotalol-induced changes in ventricular function. Late follow-up studies disclosed that antiarrhythmic efficacy and tolerance were maintained in the majority of patients. Repeat radionuclide angiography at 6 months revealed no late drug-induced depression of left ventricular function. Sotalol appears to be an effective and well tolerated agent for treatment of complex ventricular ectopic activity, even in the setting of compromised cardiac function.

Adult↗
PubMed1992

[The potential significance of early effort myocardial scintigraphy following PTCA].

Exercise 201Tl scintigraphy before and after successful PTCA was evaluated in 69 patients with coronary stenosis > 60%. Mean luminal stenosis was found reduced from 74 +/- 10% to 31 +/- 11% (58% reduction). Scintitomographic examination within 3 weeks following intervention showed a reduction of the exercise perfusion defect from 17.00 +/- 14.6 to 5.8 +/- 7.8 arbitrary units (66% reduction). Angiographically, re-stenosis was identified in 22/41 patients (54%) after 6 months. Unexpectedly, re-stenosis could not be predicted by early 201Tl scintigraphy (positive and negative predictive value in patients with single-vessel disease: 61% and 41%, resp.). Nevertheless, evaluation of PTCA results was possible (sensitivity 83%). However, postinterventional transient defects, indicating ischemia, were often seen (all patients: 43/69; patients with single-vessel disease: 31/55) and not indicative of failure of the intervention. Thus, post-PTCA scintigrams should be compared with scintigrams recorded before the intervention to ensure reliable follow-up control.

Adult↗
PubMed1992

[Diagnostic procedures in acute gastrointestinal hemorrhage].

In gastrointestinal bleeding, the diagnosis is predominantly made by endoscopy. However, if the bleeding site is in a part of the intestine that cannot be reached by endoscopy, than the diagnosis is based on radiological and scintigraphic methods. In the past 5 years 35 patients with such cases of gastrointestinal bleeding had angiography and/or scintigraphy (n = 15) in our department. Based on our retrospective study of those cases, we advocate a management protocol for such patients based on the hemodynamic presentation.

Adolescent↗
PubMed1991

Relation of technetium-99m pyrophosphate accumulation to time interval after onset of acute myocardial infarction as assessed by a tomographic acquisition technique.

Technetium-99m pyrophosphate (Tc-99m PYP) myocardial scintigraphy was performed in 110 clinically stable patients with acute or healed acute myocardial infarction (AMI). Tomography was performed 12 hours to 7 days (group A), 7 to 30 days (Group B), 1 to 6 months (Group C) and after greater than 6 months (group D) after AMI. All 40 patients in group A, 9 of 31 in group B, 1 of 22 in group C, and no patient (0 of 17) in group D had a pathologic Tc-99m PYP tomogram. Relative Tc-99m PYP accumulation within the area of infarction was measured as infarct zone to blood pool ratio, which decreased significantly (p less than 0.001) from group A (1.54 +/- 0.39) to group B (0.89 +/- 0.24), group C (0.8 +/- 0.19) and group D (0.76 +/- 0.13). These data were confirmed by sequential scintigraphy in 17 patients. It is concluded that a persisting Tc-99m PYP uptake is rarely found greater than 1 month after AMI using tomographic imaging techniques in clinically stable patients with coronary artery disease. Positive results on Tc-99m PYP tomography are a reliable indicator of AMI. Thus, Tc-99m PYP tomography is not only a sensitive but also a specific imaging technique for AMI, which might be especially useful for diagnosis of reinfarction.

Adult↗