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Biomedical subjects

J Kirchner

Publications and source records attributed to J Kirchner.

At least 19 recordsLinked to original sources
PubMed2002

[Observing the density increase curve after intravenous contrast medium administration using a bolus triggering system: a method for detection cardiovascular disorders?].

PURPOSE: Recently bolus tracking systems were developed to improve the timing of intravenous contrast media application in helical computed tomography. We investigated the benefit of this new method as a parameter of the cardiac function. MATERIAL AND METHODS: Retrospective analysis of 64 patients which incidentally underwent bolus triggered contrast enhanced helical CT and invasive investigation of the heart within one week. All examinations were performed on the CT scanner Somatom Plus 4 Volume Zoom (Siemens Corp., Forchheim, Germany) using the C.A.R.E. Bolus software. This performs repetitive low-dose test scans (e.g. for the abdomen: 140 kV, 20 mA, Tl 0.5 s) and measures the Hounsfield attenuation (increase over the baseline) in a preselected region of interest. The displayed increase of vascular density over the time after peripheral contrast media injection (75 ml lopromid (300 mg/ml), 2 ml/s) was categorised to three types: (a) rapid increase, (b) deceleration before a 100 HE threshold was reached and (c) one or more peaks. The findings of the invasive investigation of the heart were correlated to the findings of the bolus-tracking measurements. RESULTS: The examinations were categorized as follows: 19 type A, 34 type B, 11 type C. We found a high significant correlation between the type of the Hounsfield attenuation and systolic pressure in the left ventricle. There was no correlation between the type of the Hounsfield attenuation and the diastolic pressure in the left ventricle, the pressures related to the right ventricle or the ejection fraction. The bolus-tacking system showed a sensitivity of 53, a specificity of 82, an accuracy of 70%, a positive predictive value of 70% and a negative predictive value of 70% in detection of left heart failure. CONCLUSION: The bolus tracking system C.A.R.E.-bolus often shows atypical Hounsfield attenuation in cases of cardiac failure but is not suitable as a screening method of the cardiopulmonary function.

Absorptiometry, Photon↗
PubMed2002

[Mammographic positioning: how does it affect the gynecologist?].

High quality in breast imaging is of utmost importance for early diagnosis of breast cancer. Conventional x-rays are usually taken in 2 perpendicular views. This technique allows precise spacial localization of pathologic findings. Since 1983 mediolateral oblique (MLO) instead of mediolateral (ML)-projections have been recommended because they supposedly include more of the axillary tail of breast tissue. This makes sure that more carcinomas located in the axillary tail of breast tissue are detected. It is planned that MLO-positioning will be required as European quality standard for mammography. Our investigations show, however, that the MLO-projection has a number of distinct disadvantages that need to be discussed. Only 7 % of women at the most have an axillary tail demanding MLO positioning. Precise localization of a tumor is not possible anywhere in the breast if an MLO-projection is used. MLO positioning furthermore causes faese positives, so-called pseudolesions that demand further work-up. Radiotherapy is difficult because the tumorbed cannot be localized and thus precise saturation is not possible.

Breast↗
PubMed2002

Stereoscopic 3D CT vs standard 3D CT in the classification of acetabular fractures: an experimental study.

The accuracy of stereoscopic and standard three-dimensional (3D) CT in the classification of acetabular fractures was compared. A receiver operating characteristic (ROC) analysis was performed by two radiologists and two surgeons blinded to the presence of acetabular fractures in an animal model (a total of 62 porcine hips, 40 with artificial acetabular fractures). Classification of acetabular fractures was adopted from the literature. Interpretation was performed on a workstation using two specific volume rendering algorithms; unshaded and shaded bone. The ROC analysis did not demonstrate any benefit in stereoscopic 3D CT compared with standard 3D CT.

Acetabulum↗
PubMed2001

Magnetic resonance imaging in the diagnosis of Fournier's gangrene.

Magnetic resonance imaging and ultrasound are the imaging modalities recommended in the early diagnosis of Fournier's gangrene. Because of the high mortality of this inflammatory disease early diagnosis is essential to initiate adequate surgical and medical treatment. In the clinical literature only a handful of cases, in which diagnosis of Fournier's gangrene is based on MRI findings, have been reported; therefore, we report another case which shows the ability of MRI especially to determine the point of origin and extension of disease.

Adult↗
PubMed2001

Transformation of Hodgkin's disease to high-grade B-cell lymphoma: remission after Rituximab monotherapy.

PURPOSE: We demonstrate the usefulness of immunotherapy with the CD20 antibody Rituximab in a case of transformation of Hodgkin's disease (HD) to high-grade non-Hodgkin's lymphoma (NHL). CASE REPORT: A 45-year-old women suffering from lymphocyte predominant HD of paragranuloma type (stage IVb) since 1995 showed mediastinal relapse despite of 6 cycles of chemotherapy following the COPP/ABVD-protocol in 1998. Again complete remission could be achieved after escalated BEA-COPP II therapy in May 1998. Six months later chest radiograph and CT depicted pulmonary nodules. The non-typical resection of the lung revealed pulmonary involvement of a high-grade T-cell rich large B-cell lymphoma with 100% of the tumoral cells CD20 positive. Since the symptoms occurred shortly after the BEA-COPP-escalated protocol chemotherapy resistance had to be assumed. Because of this problems and supported by the refusal of a high-dose chemotherapy with stem-cell transplantation by the patient we decided to perform a mono-immunotherapy with the monoclonal CD20 antibody Rituximab. Today, 14 months later, the patient is still in complete remission including the absence of B symptoms. CONCLUSIONS: Immunotherapy against CD20 positive cells in cases of sequential HD and NHL seems to be an effective therapy in chemotherapy resistant cases because of the suspected clonally relation of both diseases.

Antibodies, Monoclonal↗
PubMed2001

Efficacy of daily bedside chest radiography as visualized by digital luminescence radiography.

To determine the diagnostic impact of daily bedside chest radiography in comparison with digital luminescence technique (DLR; storage phosphor radiography) and conventional film screen radiography, a prospective randomized study was completed in 210 mechanically ventilated patients with a total of 420 analysed radiographs. The patients were allocated to two groups: 150 patients underwent DLR, and 60 patients underwent conventional film screen radiography. Radiological analysis was performed consensually and therapeutic efficacy was assessed by the clinicians. There was no statistical significant difference between the frequency of abnormal findings seen on DLR and conventional film screen radiography. In total, 448 abnormal findings were present in 249 of 300 DLR and 97 of 120 conventional film screen radiographs. The most common findings were signs of overhydration (41%), pleural effusion (31%), partial collapse of the lung (11%) and pneumothorax (2%). One hundred and twenty-three of 448 (27%) of these abnormal findings were thought to have a considerable impact on patient management. The high rate of abnormal findings with significant impact on patient management suggests that the use of daily bedside chest radiography may be reasonable.

Adolescent↗
PubMed2001

[Optimization of the indications for breast biopsy by preoperative conference].

In connection with a series of second reviews of mammographies as part of a preoperative conference, criteria are presented that allow a correct diagnosis, thus avoiding unnecessary breast surgery. In addition, it is shown that preoperatively all diagnostic findings must be reviewed as a whole, in order to make the appropriate decision for the patient. A total of 145 patients was admitted for breast surgery between 1994 and 1997. Group 1: The mammographies of 133 patients were re-evaluated and additional exams were performed. In only 17% (23 cases) could the first diagnosis be confirmed and the patients went to surgery. In 110 cases a single mammographic view sufficed to show that there was no suspicious finding in the breast. Instead there was a pseudolesion, not visible after an image had been taken with appropriate technique. Group 2: For 12 additional patients, a synopsis of different findings was presented and analysed at a preoperative conference. Even although imaging may have been performed correctly, a conference can still contribute to the optimization of indocations. Unnecessary breast surgery can can thus be avoided.

Biopsy↗
PubMed2001

Molecular genetic dissection of TAF25, an essential yeast gene encoding a subunit shared by TFIID and SAGA multiprotein transcription factors.

We have performed a systematic structure-function analysis of Saccharomyces cerevisiae TAF25, an evolutionarily conserved, single-copy essential gene which encodes the 206-amino-acid TAF25p protein. TAF25p is an integral subunit of both the 15-subunit general transcription factor TFIID and the multisubunit, chromatin-acetylating transcriptional coactivator SAGA. We used hydroxylamine mutagenesis, targeted deletion, alanine-scanning mutagenesis, high-copy suppression methods, and two-hybrid screening to dissect TAF25. Temperature-sensitive mutant strains generated were used for coimmunoprecipitation and transcription analyses to define the in vivo functions of TAF25p. The results of these analyses show that TAF25p is comprised of multiple mutable elements which contribute importantly to RNA polymerase II-mediated mRNA gene transcription.

Amino Acid Sequence↗
PubMed2001

Identification and characterization of thymus LIM protein: targeted disruption reduces thymus cellularity.

We have identified a novel LIM gene encoding the thymus LIM protein (TLP), expressed specifically in the thymus in a subset of cortical epithelial cells. TLP was identified as a gene product which is upregulated in a thymus in which selection of T cells is occurring (Rag(-/-) OT-1) compared to its expression in a thymus in which selection is blocked at the CD4+ CD8+ stage of T-cell development (Rag(-/-) Tap(-/-) OT-1). TLP has an apparent molecular mass of 23 kDa and exists as two isomers (TLP-A and TLP-B), which are generated by alternative splicing of the message. The sequences of TLP-A and TLP-B are identical except for the C-terminal 19 or 20 amino acids. Based on protein sequence alignment, TLP is most closely related to the cysteine-rich proteins, a subclass of the family of LIM-only proteins. In both medullary and cortical thymic epithelial cell lines transduced with TLP, the protein localizes to the cytoplasm but does not appear to be strongly associated with actin. In immunohistochemical studies, TLP seems to be localized in a subset of epithelial cells in the cortex and is most abundant near the corticomedullary junction. We generated mice with a targeted disruption of the Tlp locus. In the absence of TLP, thymocyte development and thymus architecture appear to be normal but thymocyte cellularity is reduced by approximately 30%, with a proportional reduction in each subpopulation.

Actins↗
PubMed2001

Melanoptysis: findings on CT and MRI.

The purpose of this study was to demonstrate the CT and MRI features of liquefied progressive massive fibrosis (PMF) in coal worker's pneumoconiosis (CWP). A retrospective analysis was made of the CT and MRI features in five patients suffering from severe CWP with the initial clinical finding of melanoptysis ("black phtisis"). CT showed either an air-fluid level or a fluid-precipitate level with high density in the dependent layer. On pre-contrast T(1) weighted images, liquefied PMF showed a fluid level with isointensity relative to soft tissue in the upper layer and a signal loss in the dependent layer of the lesion. The wall of the PMF showed rim enhancement after administration of iv gadolinium. On T(2) weighted images there was a high signal intensity in the upper layer of the lesion. In conclusion, liquefied PMF results in characteristic features on CT and MRI owing to precipitation of silica in the mucous fluid.

Aged↗
PubMed2001

[Pulmonary lymphangioleiomyomatosis--review and personal results].

Pulmonary lymphangioleiomyomatosis (LAM) is characterised by the proliferation of smooth muscle cells in the peribronchial, perivascular and perilymphatic tissue resulting in severe destructive changes of the lung parenchyma. We reviewed the literature and compared the findings in chest radiograph and CT with our own results obtained in a group of 12 patients suffering from histological proven LAM. The main findings of LAM in chest radiograph are a diffuse reticular opacity and an increased lung volume, often large cysts are visible. The CT scans reveal that cystic lesions are present in all patients, but the reported size of the cystic lesions is contradictory. We postulate two main types of LAM: the one resulting in a diffuse distribution of multiple small cysts, partially demonstrating a honey-combing pattern, the other showing severe destruction of the lung parenchyma due to large cysts. The presence of fibrotic changes and architectural distraction does not exclude LAM. So chest radiograph as well as computed tomography reveal neither uniform nor pathognomonic findings. Differential diagnosis of LAM seems to be more difficult than most authors believe.

Adult↗
PubMed2001

["Phtisis atra"--a now seldom disease picture as a special disease course of silicosis].

Progressive massive fibrosis (PMF) of the lung is caused by coalescence of fibrotic nodules. The center of the PMF often displays necrotic areas. If the necrosis gets in contact to the bronchial system cavitation may occur. We report on a 68 year old patient suffering from severe silicosis of the lung and metastatic spread of a histologically proven lung cancer into the brain. The patient who was administered to the hospital under the intention of cerebral radiotherapy showed a colliquative PMF in the right upper lobe with cavitation and expectoration of large amounts of black-stained sputum (melanoptysis).

Adenocarcinoma↗
PubMed2000

[Antiphospholipid antibody syndrome as the cause of clinical rapidly progressing vasculopathy].

HISTORY AND ADMISSION FINDINGS: For 3 weeks a 54-year-old man had been unsuccessfully treated with antibiotics for ulcerating tonsillitis with fever, weight loss, occasional headaches, and hypertension. A year before he had suffered a transitory cerebral ischaemic attack. On admission he had a fever of 38.6 degrees C, blood pressure of 185/100 mmHg and a nonspecific 2/6 apical systolic murmur. INVESTIGATIONS: Erythrocyte sedimentation rate was 100/120 mm, C-reactive protein 1.5 mg/dl, serum creatinine 2.45 mg/dl, urinary protein 0.8 g/d. Tests for antinuclear antibodies (ANCA) against neutrophil granulocytes and for native DNA antibodies were negative, as were serological tests for Coxsackie virus, Cytomegalovirus and Epstein-Barr virus. Sonography and computed tomography revealed thrombosis along the entire aortic wall, renal artery stenosis and a contracted left kidney. Transoesophageal echocardiography demonstrated small thrombi on the aortic valve leaflets. Coloscopy showed ulcerative colitis. TREATMENT AND COURSE: The patient was anticoagulated. Local cold produced livedo reticularis. Tests for cardiolipin antibodies in serum and a skin biopsy provided the diagnosis of antiphospholipid antibody syndrome (APS). As the skin biopsy showed vasculitis, immunosuppressive treatment was started. This stabilized the condition and he was discharged to be followed by his general practitioner. CONCLUSION: APS can cause complex symptoms in many organs, but effective treatment (anticoagulation, corticosteroids, immunosuppressives) is available, as this case demonstrates.

Antibodies, Anticardiolipin↗
PubMed2000

[Computerized tomography detection of portal vein air accumulation in severe gastroenteritis during chemotherapy].

Portal venous gas is caused by various pathological processes, both iatrogenic (complications of endoscopy) and non-iatrogenic (bowel ischemia, obstruction, perforated gastric ulcer, septicaemia). We report an immunocompromised patient suffering from metastatic cancer of the breast who developed severe gastroenteritis. Plain radiographs of the abdomen showed branching tubular lucencies that extended from the porta hepatis widely over the liver. A computed tomography performed to exclude air in the biliary tract demonstrated portal venous gas. Although the finding of portal venous gas has been associated with a high mortality rate and usually necessitates surgery, our patient survived without surgical intervention.

Adult↗
PubMed2000

[Computed tomography and magnetic resonance tomography in tuberculous spondylitis. A review of the literature and the authors' own observations].

PURPOSE: The findings of tuberculous spondylitis in MRT have been described extensively. Nevertheless the diagnostic value of both methods in the diagnosis of this severe manifestation of the tuberculous disease was not yet defined definitely. MATERIALS: We performed a review of the recent literature and a retrospective analysis of the findings in ten patients with proven tuberculous spondylitis. Here we evaluated 10 CT and 6 MRT. RESULTS: Major findings in computed tomography (n = 10) were osseous sequestration (8/10), subperiosteal bone apposition (6/10), abscess of the surrounding tissue. (8/10) and calcification of the masses (3/10). In all cases which were examined by MRT (n = 6) marrow edema was seen. Affection of the soft tissue was described by means of MRT in 5/6 patients. All patients showed rim enhancement. CONCLUSIONS: MRT shows signs of infection (bone marrow edema) which is an early but rather unspecific finding. The commonness of osseous lesions in advanced tuberculous spondylitis suggests a benefit of computed tomography in the later stages. Both methods are complementary in the differential diagnosis of tuberculous and non-specific spondylitis.

Adult↗
PubMed2000

Depression after alcohol treatment as a risk factor for relapse among male veterans.

We examined the association between relapse-to-drinking and depressive symptomatology measured during inpatient treatment for alcohol disorder and 3 months posttreatment. Data were obtained from 298 veterans who completed 21-day inpatient treatment. Follow-up interviews were conducted at 3, 6, 9, and 12 months posttreatment. We used multiple logistic regression to assess the association between relapse and baseline/3-month posttreatment measures of depression (Beck Depression Inventory; BDI), controlling for important covariates. Our results showed that (a) the mild-to-moderately symptomatic participants (BDI = 14-19) at 3 months posttreatment were on average 2.9 times more likely than the nondepressed to have relapsed across follow-ups, and (b) the severely symptomatic participants (BDI = 20+) at 3 months posttreatment were on average 4.9 times more likely to have relapsed across follow-ups. Other analyses revealed that those with persistent depressive symptomatology reported at both baseline and 3 months posttreatment did not experience worse outcomes that those who reported symptomatology at 3 months posttreatment alone.

Alcoholism↗
PubMed2000

Cargo binding and regulatory sites in the tail of fungal conventional kinesin.

Here, using a quantitative in vivo assay, we map three regions in the carboxy terminus of conventional kinesin that are involved in cargo association, folding and regulation, respectively. Using C-terminal and internal deletions, point mutations, localization studies, and an engineered 'minimal' kinesin, we identify five heptads of a coiled-coil domain in the kinesin tail that are necessary and sufficient for cargo association. Mutational analysis and in vitro ATPase assays highlight a conserved motif in the globular tail that is involved in regulation of the motor domain; a region preceding this motif participates in folding. Although these sites are spatially and functionally distinct, they probably cooperate during activation of the motor for cargo transport.

Adenosine Triphosphatases↗