[The involvement of the corpus callosum in systemic lupus erythematosus].
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Adult↗
Biomedical subjects
K Hahn
Publications and source records attributed to K Hahn.
[Recommendations for the performance of DMSA scintigraphy in children].
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Child↗
Regional differences in the metabolism of Tyr-MIF-1 and Tyr-W-MIF-1 by rat brain mitochondria.
Tyr-MIF-1 (Tyr-Pro-Leu-Gly-NH2) and Tyr-W-MIF-1 (Tyr-Pro-Trp-Gly-NH2) are endogenous neuropeptides with opiate modulating and other CNS effects. After incubation of the tritiated tetrapeptides with fractions of tissue from different areas of rat brain, formation of the metabolites was determined by HPLC. Marked regional differences in degradation were found for both peptides. The metabolism of Tyr-MIF-1, resulting in the formation of the biologically active MIF-1 (Pro-Leu-Gly-NH2), was greater in the mitochondrial than in the synaptosomal fractions. In the mitochondrial fraction, about twice as much MIF-1 was formed in brain cortex than in striatum, diencephalon, or midbrain/pons medulla. These results, showing differential metabolism in various areas of the brain, indicate another means for regulation of the concentrations of neuropeptides.
Animals↗
Technetium-99m mercaptoacetyltriglycine clearance values in children with minimal renal disease: can a normal range be determined?
Use of technetium-99m labelled mercaptoacetyltriglycine (99mTc-MAG3) simplifies and improves the quantification of renal clearance in children by virtue of its permanent availability, good imaging properties and low radiation exposure. Due to the lack of reference values for 99mTc-MAG3 clearance in children, the Paediatric Task Group of the EANM initiated a multicentre study to evaluate 99mTc-MAG3 clearance values in children with minimal renal disease. One hundred and twenty-five children aged between 12 months and 17 years, classified as renally healthy using defined diagnostic criteria, were included in the study. 99mTc-MAG3 clearance was calculated using an algorithm on the basis of a single blood sample taken at any time between 30 and 40 min after tracer injection. In addition, the absolute 99m-Tc-MAG3 clearance values were normalized to body surface area. For further evaluation the children were classified into several groups according to age. There was a continuous increase in non-corrected 99mTc-MAG3 clearance values from the age of 1 year up to the age of 17 years (mean value <2 years: 98+/-57 ml/min; mean value >8 years: 208+/-66 ml/min). Normal clearance values for adults were achieved by the age of 8 years. Analysis of the relationship between non-corrected clearance and age yielded a correlation coefficient of r=0.7. When these absolute clearance values were normalized to body surface area, we found nearly constant clearance values for all age groups, with a mean clearance value of 315+/-114 ml/minx1.73 m2. The correlation coefficient for the relationship between normalized clearance and age was r=0.28. In conclusion, the clearance of 99mTc-MAG3 increases continuously throughout childhood into adolescence due to the maturation and growth of the kidney. After normalization of the absolute clearance to body surface area, no correlation between clearance and age could be proven.
Child↗
ST segment elevation and the prediction of hospital life-threatening complications: the role of right ventricular and posterior leads.
UNLABELLED: Accurate prognosis in suspected acute myocardial infarction (AMI) is essential for appropriate use of thrombolytic therapy and primary angioplasty. However, previous models may be limited because the 12-lead electrocardiogram (ECG) does not examine the right ventricular (RV) and posterior myocardium. We evaluated ST segment elevation (STSE) in posterior (V7-V9) and RV (V4R-V6R) leads to determine their predictive value for hospital life-threatening complications (HLTCs). METHOD AND RESULTS: This prospective trial of seven Midwestern hospital emergency departments (EDs) had inclusion criteria of age 35 years, chest pain suggestive of ischemia, and coronary care unit (CCU) admission. ECG leads were test positive if STSE was > 0.1 mV. Patients were positive for HLTCs if ED or inpatient hospital course included: ventricular fibrillation or tachycardia, second- or third-degree block, shock, arrest, or death. Univariate and multivariate analyses were performed to test each lead's association with HLTCs. Of 533 patients, 64.7% (345/533) had AMI and 15.8% (85/533) had HLTCs. The sensitivity of 18 leads for HLTCS was increased by 5.8%, but specificity decreased by 8.2%. ECG subgroups by STSE were associated with the following HLTC rates: inferior/+RV (32.4%); anterior (29.5%), lateral (23.1%), inferior RV (17.9%), and posterior (16.2%). V1 (odds = 3.2) and V6R (odds = 3.1) were statistically significant independent predictors. CONCLUSION: Posterior and RV leads did not increase the ECG's overall prognostic value, but in the presence of inferior STSE, were associated with low and high complication rates, respectively. Right and left precordial leads were the best predictors of HTLCs.
Adult↗
hpaA mutants of Xanthomonas campestris pv. vesicatoria are affected in pathogenicity but retain the ability to induce host-specific hypersensitive reaction.
Xanthomonas campestris pv. vesicatoria is the causal agent of bacterial spot disease on pepper and tomato plants. We reported previously that the main hrp (hypersensitive reaction and pathogenicity) gene cluster in X. c. pv. vesicatoria contains six transcription units, designated hrpA to hrpF. We present here the sequence of the hrpD operon and an analysis of non-polar mutants in each of the six genes. Three genes, hrcQ, hrcR and hrcS, are predicted to encode conserved components of type III protein secretion systems in plant and mammalian pathogenic bacteria. For hrpD5 and hrpD6, homologues have only been found in Ralstonia solanacearum. Interestingly, the hrpD operon contains one gene, hpaA (for hrp-associated), which is specifically required for disease development. hpaA mutants are affected in pathogenicity, but retain in part the ability to induce avirulence gene-mediated, host-specific hypersensitive reaction (HR). In addition, HpaA was found to contain two functional nuclear localization signals, which are important for the interaction with the plant. We propose that HpaA is an effector protein that may be translocated into the host cell via the Hrp secretion pathway.
Amino Acid Sequence↗
[Dosimetry in conventional and spiral CT in 8 spiral CT scanners of the latest generation].
PURPOSE: Measurement of scanner-dependent differences in PCTDI for conventional and spiral CT and evaluation of PCTDI/100 mAs in eight spiral CT scanners of the latest generation. METHODS: Central PCTDI was evaluated in a PMMA phantom for different scan lengths of conventional and spiral CT in four scanners. Central and peripheral PCTDI/100 mAs, average dose and the quotient between peripheral and central PCTDI/100 mAs were measured with a dedicated 10 cm ionisation chamber positioned within a PMMA phantom using the parameters of a standardised liver protocol and a high-resolution inner ear protocol for eight spiral CT scanners. RESULTS: Depending on scanner type and scan length PCTDI for the spiral mode is in a range between 11.3% higher and 4.3% lower than that for the conventional mode. PCTDI/100 mAs varies considerably between different CT scanners. For the standardised liver protocol PCTDI/100 mAs varies up to a factor of 2, for the inner ear protocol up to a factor of 4. CONCLUSION: Even in comparable modern CT scanners there are considerable protocol and scanner-dependent differences in PCTDI/100 mAs. The values for his own scanner should be known to each CT user so that he can develop a dose-optimised, patient and problem-orientated examination strategy.
Ear, Inner↗
Time resolving ionization monitor for microsecond radiation impulses.
The current induced in the outer circuit of a fast response ionization chamber exposed to pulsed radiation consists of two components, a fast one induced by free electrons and a slow one induced by ions. The fast electron component may be used for the representation of the shape of the ionizing pulse. In order to avoid interference with the slow ion current, the latter has to be removed from the signal. This is achieved by deriving a voltage course from the chamber signal which fits the shape of the ion component and subtracting this from the entire signal. The function of the electronic circuit used for this purpose is described. Some considerations about the time resolution of the chamber gas are to be found in the appendix.
Electronics↗
Limited value of scintimammography and contrast-enhanced MRI in the evaluation of microcalcification detected by mammography.
The aim of this study was to evaluate whether scintimammography using 99Tc(m)-sestamibi or contrast-enhanced magnetic resonance imaging (MRI) can improve the specificity of mammography for the differentiation of benign and malignant breast microcalcification. From 156 consecutive patients studied with SMM, 44 patients with microcalcification on mammograms were selected for this study. Forty patients in this group also had contrast-enhanced MRI of the breast. The intensity and patterns of sestamibi uptake for scintimammography and contrast enhancement for MRI were visually determined and graded on a 5-point scale for malignancy. The results of both techniques were compared and correlated with final histopathologic diagnoses. The sensitivity and specificity of scintimammography were 63% and 85% respectively, if only those cases classified as probable or definite malignancy were considered positive. If indeterminate findings were also considered positive, the sensitivity and specificity of scintimammography were 79% and 80% respectively. Using the latter classification for MRI revealed a comparable sensitivity of 82% but a markedly lower specificity of 56%. Excluding indeterminate findings from the group of positive MRI diagnoses resulted in a specificity of 94% and a sensitivity of 64%. In conclusion, scintimammography of the breast had a comparable sensitivity but a higher specificity than MRI. The sensitivity of both techniques, however, is probably too low for routine use in the evaluation of microcalcification detected by mammography.
Adult↗
Radiation dose and image quality in spiral computed tomography: multicentre evaluation at six institutions.
The purpose of this study was to evaluate the correlation of radiation dose with image quality in spiral CT. Seven clinical protocols were measured in six different radiological departments provided with four different types of high specification spiral CT scanners. Central and surface absorbed doses were measured in acrylic. The practical CT dose index (PCTDI) was calculated for seven clinical examination protocols and one standardized protocol using identical parameters on four different spiral CT scanners with a dedicated ionization chamber inserted into PMMA phantoms. For low contrast measurements, a cylindrical three-dimensional (3D) phantom (different sized spheres of defined contrast) was used. Image noise was measured with a cylindrical water phantom and high contrast resolution with a Perspex hole phantom. Image quality phantoms were scanned using the parameters of the clinical protocols. Images were randomized, blinded and read by six radiologists (one from each institution). PCTDI values for four different scanners varied up to a factor between 1.5 (centre) and 2.2 (surface) for the standardized protocol. A greater degree of variation was observed for seven clinical examination protocols of the six radiological departments. For example, PCTDI varied up to a factor between 1.7 (cerebrum protocol) and 8.3 (abdomen paediatric protocol). Low contrast resolution correlates closely with dose. An improvement in detection from 8 mm to 4 mm sized spheres needs approximately a ten-fold increase in dose. Noise shows a moderate correlation with PCTDI. High contrast resolution of clinical protocols is independent of PCTDI within a certain range. Differences in modern CT scanner technology seem to be of less importance for radiation exposure than selection of protocol parameters in different radiological institutes. Future discussion on guidelines regarding optimal (patient adapted) tube current for clinical protocols is desirable.
Brain↗
Prospective evaluation of MR arthrography performed with high-volume intraarticular saline enhancement in patients with recurrent anterior dislocations of the shoulder.
OBJECTIVE: The purpose of this study was to evaluate the accuracy of high-volume saline-enhanced MR arthrography in assessing the labrum, the ligaments, and the bony components of the glenohumeral joint. SUBJECTS AND METHODS: Forty-four patients with recurrent anterior dislocations of the shoulder underwent MR arthrography after intraarticular injection of 15-40 ml of saline solution. Two-dimensional fast low-angle shot and T1-weighted spin-echo sequences were prospectively evaluated by two observers. Anterior (Bankart) lesions, superior labral lesions extending from anterior to posterior, and Hill-Sachs lesions were diagnosed. Glenohumeral ligaments (GHLs) were identified and classified using a standard system. MR imaging results were compared with those of arthroscopy (n = 32) or open surgery (n = 12), either of which was the gold standard. RESULTS: Bankart lesions and superior labral lesions extending from anterior to posterior were revealed with a sensitivity of 93% and 89%, respectively, and a specificity of 80% and 89%, respectively. Diagnostic accuracy was 89% for both types of lesions. All six patients with bony Bankart lesions had high fat-marrow signal intensity within the fragment on T1-weighted MR images. For GHLs, MR imaging results and arthroscopy correlated in 25 of the 31 patients. In three patients all three GHLs were visible on MR imaging, but only two GHLs were detected with arthroscopy. In three patients two GHLs were detected on MR imaging but all three were visible on arthroscopy. Hill-Sachs lesions were revealed with a sensitivity of 95%, a specificity of 50%, and an accuracy of 81%. CONCLUSION: High-volume saline-enhanced MR arthrography is accurate in revealing the labrum, the ligaments, and the bony components of the glenohumeral joint Saline solution is inert and inexpensive, two advantages over gadopentetate dimeglumine.
Adult↗
Technetium-99m-sestamibi scintimammography for the detection of breast carcinoma: comparison between planar and SPECT imaging.
UNLABELLED: The purpose of our study was to compare the results of planar and SPECT scintimammography for the detection of breast carcinoma. In addition, our goal was to determine whether SPECT reconstructed with filtered backprojection (FBP) or with iterative algorithms (ISA) can improve the sensitivity and specificity of planar scintimammography (SMM). METHODS: One hundred thirteen patients with suspicious physical examinations and/or mammography underwent planar lateral and anterior breast imaging as well as SPECT imaging after injection of 99mTc-sestamibi. We used a blind evaluation, both separately and combined, for planar SMM, ISA-SPECT and FBP-SPECT. Scintigraphic findings were correlated with the final histopathological diagnoses. RESULTS: The sensitivity of planar SMM was 80% with a specificity of 83%. All ISA-SPECT studies were of diagnostic quality, while FBP-SPECT was considered nondiagnostic in 14 that were excluded for statistical calculation. Sensitivity of ISA-SPECT and FBP-SPECT were 71% and 69%, respectively. Specificity was 70% for ISA-SPECT and 66% for FBP-SPECT. Combined planar SMM plus ISA-SPECT sensitivity was 85% (81% for planar SMM plus FBP-SPECT) with a specificity of 72%. Three carcinomas indeterminate on planar SMM were correctly identified by combined planar SMM plus ISA-SPECT. ISA-SPECT and FBP-SPECT provided additional information to planar SMM with respect to localization of sestamibi uptake, tumor extent, improved diagnostic certainty and detection of axillary nodes in 40 and 14 patients, respectively. CONCLUSION: ISA reconstruction is the preferable approach to SPECT data. Combined with planar SMM, ISA-SPECT can improve sensitivity. SPECT is useful in cases of indeterminate and positive planar SMM.
Algorithms↗
Iodine-123-iodobenzamide SPECT assessment of dopamine D2 receptor occupancy in riperidone-treated schizophrenic patients.
UNLABELLED: The recently introduced neuroleptic, risperidone, was expected to block fewer dopamine D2 receptors than typical neuroleptics (e.g., haloperidol), but at comparable potency. The aim of this study was to evaluate the degree of dopamine D2 receptor occupancy in relation to the neuroleptic dosage and to correlate the findings with the presence of extrapyramidal symptoms (EPS). Additionally, the data were compared to previous iodobenzamide (IBZM) SPECT findings in patients treated with other neuroleptics, haloperidol and clozapine. METHODS: In 20 patients with schizophrenia [Diagnostic and Statistical Manual of Mental Disorders (Third Edition-Revised)] treated with mean daily doses of risperidone ranging from 0.029 to 0.128 mg/kg body weight, SPECT was performed 2 hr after intravenous injection of 185 MBq 123I-IBZM, a selective dopamine D2 receptor ligand. Striatal IBZM binding was assessed by calculating a striatal/frontal cortex ratio, expressed as a percentage of the control value. RESULTS: Selective dopamine D2 receptor binding of the ligand was reduced in all treated patients, with binding values ranging from 7% to 68%. The degree of occupancy displayed an exponential dose-response relationship (r = -0.86; p < 0.0001). The slope of the curve was between those of haloperidol and clozapine but was closer and more similar in shape to the curve of haloperidol. Extrapyramidal symptoms were observed in 8 of 20 patients with binding values between 7% and 47%. However, there was no clear relationship between the degree of receptor occupancy and the presence of EPS. CONCLUSION: The findings suggest an exponential dose-response relationship between the daily dosage of risperidone and the dopamine D2 receptor occupancy. The blockade of specific striatal IBZM binding found under therapy with risperidone is between those of haloperidol and clozapine. The dose-response curve for risperidone, however, shows greater similarity to that of haloperidol.
Adult↗
Bone scintigraphy in non-neoplastic diseases in children.
Since the introduction of 99mTc labeled polyphosphates bone scintigraphy has become a widely accepted method for the evaluation of non-neoplastic bone diseases in children. High quality images require the child's immobilisation and a correct positioning as well as an optimized technical equipment. Two or three phase scintigraphy is the routinely procedure but additional techniques like pinhole images or SPECT can be very helpful for special indications and localisations. Due to the age and sex dependent differences of bone metabolism in the developing skeleton the interpretation of the bone scan in children is more difficult than in adults and requires more experience. Infections, trauma and aseptic necrosis are the most important non-neoplastic diseases requiring bone scintigraphy. Bone scan has a high sensitivity in the early detection of pathological bone metabolism indicating bone disease; other investigations, which are describing morphological changes like X-ray are less sensitive especially at the beginning of the disease. Negative bone scan rools out significant bone disorders with a high certainty. Follow-up studies can give additional informations about the response to therapeutical regimes and about the prognosis. To improve the specificity of a bone scan a combined interpretation of scintigraphy and X-ray is recommended.
Bone Diseases↗
[Diagnosis of sentinel lymph node in malignant melanoma: preoperative lymphoscintigraphy and intraoperative gamma probe guidance].
AIM: The sentinel lymph node (SLN) has shown to reflect the histologic features of the remainder of the lymphatic basin in patients with melanoma and is of considerable prognostic relevance. Aim of the study was to localize the SLN pre and intraoperatively by means of lymphoscintigraphy and gamma probe guidance. METHODS: 38 patients with histologically proven malignant melanoma (tumor thickness > 0.75 mm) were preoperatively examined by injecting 40 MBq 99mTc-Nanocoll intradermally around the lesion. The first lymph node identified was marked on the skin. Immediately after scintigraphy patients were referred to the operation room and intraoperatively mapped using a handheld gamma probe. Activity of the SLN and of the adjacent nodes was measured ex vivo. After excision of the SLN, the lymphatic basin was re-checked for radioactivity and activity of the SLN and of the adjacent nodes was re-measured after removal. RESULTS: The hottest reading was found in all patients in vivo and ex vivo in the preoperatively marked lymph node. Morphologically (macroscopically, ultrasound, CT) all nodes were unsuspicious. Histologically, in 8 patients metastatic involvement of the lymph node was found which led to a wide exploration of the lymphatic basin with consecutive lymph node excision in 7 patients. CONCLUSION: The findings suggest that combined preoperative lymphoscintigraphy and intraoperative mapping with a gamma probe is a powerful approach for exact localization of the SLN. Diagnostic detection of the SLN may have considerable impact for patient management, since extended lymph node dissection may be confined to patients presenting with positive SLN.
Adult↗
Segment-based scores for pairwise and multiple sequence alignments.
In this paper, we discuss a novel scoring scheme for sequence alignments. The score of an alignment is defined as the sum of so-called weights of aligned segment pairs. A simple modification of the weight function used by the original version of the DIALIGN alignment program turns out to have a crucial advantage: it can be applied to both, global and local alignment problems without the need to specify a threshold parameter.
Amino Acid Sequence↗
[123I]IBZM SPECT in patients treated with typical and atypical neuroleptics: relationship to drug plasma levels and extrapyramidal side effects.
[123I]Iodobenzamide (IBZM) is an iodine-labeled dopamine receptor ligand and can be used to visualize brain D2 receptors in humans with single photon emission computerized tomography (SPECT). The ratio of striatal IBZM uptake to uptake in frontal cortex (ST/FC ratio) represents a semiquantitative measure of D2 receptor binding in the striatum. Our study sample included six patients treated with haloperidol (3.0-8.0 mg/day orally; one patient with an average of 0.9 mg/day intramuscularly), five patients with benperidol (9.0-15.0 mg/day orally) and nine patients treated with clozapine (200.0-600.0 mg/day orally). Typical neuroleptics (TNs) and atypical neuroleptics (ANs) were significantly different in their ST/FC ratios. The ST/FC ratios indicated that patients treated with benperidol exhibited the lowest ST/FC ratios, with increasingly higher ratios in patients on haloperidol or clozapine. We found a curvilinear relationship between the ST/FC ratios and the dose/kg body wt. of TNs and ANs on the basis of a dose-normalization according to Ki-values of the neuroleptic at D2 receptors and a weaker, but also curvilinear relationship between ST/FC ratios and normalized dosages according to clinically defined chlorpromazine equivalents. The specific uptake of IBZM did not correlate with the plasma levels of the TN haloperidol at the present dose range (0-12.4 ng/ml). For clozapine, a meaningful negative correlation between plasma levels and ST/FC ratio could be established. There was a negative continuous correlation between uptake of IBZM and extrapyramidal side effects, which is different from the threshold-based relationship between extrapyramidal side effects and IBZM uptake reported previously.
Adult↗
Pericardiectomy in dogs: 22 cases (1978-1994).
OBJECTIVE: To determine long-term outcome of dogs with neoplastic and nonneoplastic pericardial disease that undergo pericardiectomy. DESIGN: Retrospective study. ANIMALS: 22 dogs. PROCEDURE: Dogs that underwent pericardiectomy and in which the diagnosis had been confirmed histologically were included. Data collected from each record included signalment, history, clinical signs, results of diagnostic evaluations, operative management, postoperative complications, histologic diagnosis, and outcome. Dogs were grouped on the basis of underlying cause of pericardial disease (neoplastic vs nonneoplastic), and survival times were determined by means of Kaplan-Meier analyses. RESULTS: 9 dogs had neoplastic pericardial disease (chemodectoma, 4; hemangiosarcoma, 2; malignant mesothelioma, 2; lymphoblastic lymphoma, 1). Thirteen dogs had nonneoplastic pericardial disease (benign idiopathic pericarditis, 10; lymphocytic plasmacytic pericarditis, 2; osseous metaplasia of unknown cause, 1). Thoracic radiography and echocardiography were the most specific methods for diagnosis of pericardial effusion. Pleural effusion was the most common postoperative complication (8/22 dogs). Prevalence of postoperative complications was not associated with underlying cause of pericardial disease, surgical approach, or surgical procedure (subtotal vs total pericardiectomy). Median survival time of dogs with neoplastic disease (52 days) was significantly shorter than median survival time of dogs with nonneoplastic disease (792 days). Dogs that developed pleural effusion > 30 days after pericardiectomy had a poor prognosis for survival. CLINICAL IMPLICATIONS: Radiography and echocardiography are useful for diagnosis of pericardial effusion in dogs. Dogs with neoplastic pericardial disease have a significantly shorter survival time than do dogs with nonneoplastic pericardial disease.
Animals↗