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Biomedical subjects

C Böhm

Publications and source records attributed to C Böhm.

At least 19 recordsLinked to original sources
PubMed2007

[Negative endoscopy and MSCT findings in patients with acute lower gastrointestinal hemorrhage. Value of (99m)Tc erythrocyte scintigraphy].

PURPOSE: To evaluate the clinical use of (99m)Tc red blood cell imaging (RBC imaging) in patients presenting with acute lower gastrointestinal (GI) bleeding and negative endoscopy and multislice computed tomography (MSCT) findings. PATIENTS AND METHODS: In 31 consecutive patients with acute lower GI bleeding in whom the endoscopy findings were negative or the procedure was not feasible, dual-phase MSCT of the abdomen was performed [collimation 4x1 mm (arterial phase), 4x2.5 mm (venous phase)]. MSCT was followed by a (99m)Tc red blood cell scan in patients in whom no active bleeding was visible by CT. Images were created within 24 h after administration of the tracer, depending on the clinical symptoms. The results of the imaging modalities were correlated with clinical course and surgical treatment. RESULTS: In 20 of 31 patients MSCT showed no active bleeding and a (99m)Tc red blood cell scan was performed. In 8 of 20 patients RBC imaging was also negative. Of these eight patients five were stable and did not require further diagnostic work-up; in the other three bleeding persisted and these patients required surgical treatment. In 12 of 20 patients active bleeding was demonstrated using a (99m)Tc red blood cell scan. Of 12 patients with positive RBC scintigraphy findings, 8 underwent surgery, where the site of bleeding was confirmed. CONCLUSION: In patients with acute lower GI bleeding with negative or nondiagnostic endoscopy or MSCT findings, (99m)Tc red blood cell imaging is a useful tool in an emergency algorithm, improving the overall bleeding detection rate.

Acute Disease↗
PubMed2006

Detection of Aspergillus DNA in cerebrospinal fluid from patients with cerebral aspergillosis by a nested PCR assay.

Invasive aspergillosis (IA), a complication with high mortality rates, especially in disseminated IA with cerebral involvement, is difficult to diagnose. Biopsy of cerebral lesions is often not feasible, and culture of Aspergillus spp. from cerebrospinal fluid (CSF) is frequently negative. New molecular methods have emerged for diagnosing IA. So far, there are only few reports of Aspergillus DNA detection in CSF. After modifying the DNA extraction protocol, we detected Aspergillus DNA in CSF samples by a previously described nested PCR assay. In six patients with hematologic malignancy and cerebral aspergillosis, CSF samples were investigated for Aspergillus DNA. IA was classified according to the EORTC/MSG 2002 criteria. Two patients each had proven, probable, and possible IA. Thirty-five CSF samples were investigated for Aspergillus DNA by nested PCR. Samples with positive results in the nested PCR assay were quantified by LightCycler PCR assay. Fourteen CSF samples showed positive results in the nested PCR assay. Of these, six samples gave positive results in real-time PCR. The range of CFU per ml was 2,154 to 63,100,000. The highest number of CFU per ml was found in a CSF sample of a patient with acute lymphocytic leukemia and probable cerebral aspergillosis. Detection of Aspergillus DNA in CSF samples is thus possible and has the potential to improve diagnosis of cerebral aspergillosis. Further prospective studies with larger numbers of patients must be performed to evaluate the clinical significance of Aspergillus PCR with CSF samples.

Adolescent↗
PubMed2006

Molecular characterisation of non-absorptive and absorptive enterocytes in human small intestine.

BACKGROUND AND AIMS: Perturbation of differentiation of the crypt-villus axis of the human small intestine is associated with several intestinal disorders of clinical importance. At present, differentiation of small intestinal enterocytes in the crypt-villus axis is not well characterised. SUBJECTS AND METHODS: Expression profiling of microdissected enterocytes lining the upper part of crypts or the middle of villi was performed using the Affymetrix X3P arrays and several methods for confirmation. RESULTS: A total of 978 differentially expressed sequences representing 778 unique UniGene IDs were found and categorised into four functional groups. In enterocytes lining the upper part of crypts, cell cycle promoting genes and transcription/translation related genes were predominantly expressed, whereas in enterocytes lining the middle of villi, high expression of cell cycle inhibiting genes, metabolism related genes, and vesicle/transport related genes was found. CONCLUSION: Two types of enterocytes were dissected at the molecular level, the non-absorptive enterocyte located in the upper part of crypts and the absorptive enterocyte found in the middle of villi. These data improve our knowledge about the physiology of the crypt-villus architecture in human small intestine and provide new insights into pathophysiological phenomena, such as villus atrophy, which is clinically important.

Adult↗
PubMed2006

Effects of antidepressant treatment on gene expression profile in mouse brain: cell type-specific transcription profiling using laser microdissection and microarray analysis.

A gene expression study of mice treated with the tricyclic antidepressant amitriptyline was performed. To enable the detection of cell type-specific expression changes, laser-microdissected nucleus accumbens was analysed after 4 and 28 days of treatment. After 4 days of treatment no significantly regulated genes could be detected in this study. In contrast, 95 genes exhibited different expression levels in animals treated for 28 days with amitrityline compared with sham animals. This observation reflects the long-term effects and adaptation processes observed in patients treated with this drug. Among the regulated genes are receptors belonging to the dopamine-dependent signalling cascade, ion channels (mainly voltage-dependent potassium and calcium channels) potentially involved in signalling cascades and neuropeptides. The results support the hypothesis that the therapeutic effect of this antidepressant is much more complex and not confined to a reuptake inhibition of neurotransmitters. Paradigms inducing only weak expression changes, which may be limited to certain cell types within the highly complex brain structure, can therefore be reliably investigated by applying a cell type-specific expression profiling technique based on laser microdissection and subsequent RNA amplification followed by DNA microarray analysis.

Amitriptyline↗
PubMed2004

Supervised machine learning techniques for the classification of metabolic disorders in newborns.

MOTIVATION: During the Bavarian newborn screening programme all newborns have been tested for about 20 inherited metabolic disorders. Owing to the amount and complexity of the generated experimental data, machine learning techniques provide a promising approach to investigate novel patterns in high-dimensional metabolic data which form the source for constructing classification rules with high discriminatory power. RESULTS: Six machine learning techniques have been investigated for their classification accuracy focusing on two metabolic disorders, phenylketo nuria (PKU) and medium-chain acyl-CoA dehydrogenase deficiency (MCADD). Logistic regression analysis led to superior classification rules (sensitivity >96.8%, specificity >99.98%) compared to all investigated algorithms. Including novel constellations of metabolites into the models, the positive predictive value could be strongly increased (PKU 71.9% versus 16.2%, MCADD 88.4% versus 54.6% compared to the established diagnostic markers). Our results clearly prove that the mined data confirm the known and indicate some novel metabolic patterns which may contribute to a better understanding of newborn metabolism.

Algorithms↗
PubMed2003

No evidence of tumour cells in blood of patients with glioma.

BACKGROUND: Although clinically apparent systemic metastases of gliomas are very rare, reports of gliomas developing in recipient's transplanted organs have suggested that haematogenous spread might be more common. METHODS: This report describes a newly developed, sensitive real time quantitative reverse transcription polymerase chain reaction assay for the detection of mRNA encoding glial fibrillary acidic protein (GFAP). Blood from 10 patients with astrocytoma and 10 patients with glioblastoma was analysed. RESULTS: No GFAP mRNA was detected. CONCLUSIONS: These results suggest that even subclinical metastases are very rare and are probably restricted to distinct subsets of glioma.

Biomarkers, Tumor↗
PubMed2001

Enantioselective synthesis of (-)-roccellaric acid.

[reaction in text] A new strategy for the synthesis of anti-4,5-disubstituted gamma-butyrolactones starting from inexpensive furan-2-carboxylic methyl ester was developed. By applying this methodology, the enantioselective synthesis of (-)-roccellaric acid ((-)-17) was accomplished using a copper(I)-catalyzed asymmetric cyclopropanation, a tin(IV)-catalyzed retroaldol/lactonization sequence of cyclopropanols, and a ruthenium-catalyzed intermolecular metathesis reaction as key steps.

4-Butyrolactone↗
PubMed2001

Effects of chiral fragrances on human autonomic nervous system parameters and self-evaluation.

The effects of chiral fragrances (enantiomers of limonene and carvone) on the human autonomic nervous system (ANS) and on self-evaluation were studied in 20 healthy volunteers. Each fragrance was administered to each subject by inhalation using an A-A-B design. Individuals were tested in four separate sessions; in one session one fragrance was administered. ANS parameters recorded were skin temperature, skin conductance, breathing rate, pulse rate, blood oxygen saturation and systolic as well as diastolic blood pressure. Subjective experience was assessed in terms of mood, calmness and alertness on visual analog scales. In addition, fragrances were rated in terms of pleasantness, intensity and stimulating property. Inhalation of (+)-limonene led to increased systolic blood pressure, subjective alertness and restlessness. Inhalation of (-)-limonene caused an increase in systolic blood pressure but had no effects on psychological parameters. Inhalation of (-)-carvone caused increases in pulse rate, diastolic blood pressure and subjective restlessness. After inhalation of (+)-carvone increased levels of systolic as well as diastolic blood pressure were observed. Correlational analyses revealed that changes in both ANS parameters and self-evaluation were in part related to subjective evaluation of the odor and suggest that both pharmacological and psychological mechanisms are involved in the observed effects. In conclusion, the present study indicates that: (i) prolonged inhalation of fragrances influences ANS parameters as well as mental and emotional conditions; (ii) effects of fragrances are in part based on subjective evaluation of odor; (iii) chirality of odor molecules seems to be a central factor with respect to the biological activity of fragrances.

Adolescent↗
PubMed1999

Differential gene expression in colon carcinoma cells and tissues detected with a cDNA array.

Expression of selected genes coding for proteins with defined cellular functions was analysed in human cell lines derived from normal colonic mucosa, non-mucinous colonic carcinomas and mucinous colonic carcinomas. Altered expression of 10 genes in colon carcinoma cells was found by using a cDNA array; 6 of these alterations (60%) were confirmed by Northern blotting or semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR). Among these 6 genes, 3 transcription factors as well as the topoisomerase II alpha and the mitosis inhibitor WEE1Hu gene were significantly suppressed in the tumour cell lines. In addition, the gene coding for the cell cycle inhibitor p21 was overexpressed only in cell lines derived from mucinous carcinomas. The significant suppression of the kinase WEE1Hu gene in carcinoma cells of both phenotypes and the tendency of the mucinous phenotype to overexpress p21 protein were confirmed in human colon carcinoma tissues. Our data show that the cDNA array method permits a correct identification of changes in gene expression with a relatively high accuracy. The different expression of the p21 gene in the non-mucinous and mucinous carcinoma cells supports the hypothesis that these phenotypes may develop along different genetic pathways. The detection of WEE1Hu gene suppression in colon carcinoma cells and tissues suggests its potential role in tumourigenesis.

Adenocarcinoma, Mucinous↗
PubMed1999

Aortocaval fistula complicating abdominal aortic aneurysm: diagnosis with gadolinium-enhanced three-dimensional MR angiography.

With approximately 150 reported cases, fistulas between the abdominal aorta and inferior vena cava are rare. Preoperative clinical diagnosis of aortocaval fistula is difficult because the classical triad of abdominal pain, pulsatile abdominal mass, and abdominal machinery-like bruit may be absent in up to 50 % of patients. We report a case of aortocaval fistula complicating abdominal aortic aneurysm which was diagnosed preoperatively using breath-hold gadolinium-enhanced three-dimensional MR angiography.

Aorta, Abdominal↗
PubMed1999

FasL is more frequently expressed in liver metastases of colorectal cancer than in matched primary carcinomas.

Colorectal carcinoma cells have recently been shown to express Fas ligand (FasL). This ligand could allow the tumour cells to evade activated tumour-infiltrating lymphocytes (TILs) by inducing their apoptosis and would thus promote tumour survival and possibly metastasis formation. To test this hypothesis in vivo we analysed the expression of FasL mRNA and protein in paired tissue samples of normal colonic mucosa (N), primary colorectal carcinomas (T) and their metastases (M) from a total of 21 patients by four different methods. Additionally, the presence and activation status of infiltrating lymphocytes, which might contribute to the total amount of FasL in the tissue, was determined by semiquantitative reverse transcription-polymerase chain reaction (RT-PCR) in the same samples. The frequency of FasL detection was 30-40% in T and was 60-100% in M, depending on the sensitivity of the method. Simultaneously, the amount of CD25 mRNA, used as a measure of the number of activated TILs, was in 90% of patients lower in M than in T. The increased frequency of FasL detection in liver metastases was therefore not due to the presence of activated TILs. We conclude that metastasizing subpopulations of colorectal tumour cells express FasL more frequently than the primary carcinomas and may be able to eliminate activated TILs in vivo via Fas/FasL-induced apoptosis or other hitherto unknown mechanisms.

Colorectal Neoplasms↗
PubMed1999

[Comparison of conventional and high resolution 2D RARE MRCP in diagnosis of pancreaticobiliary diseases].

PURPOSE: Evaluation of high-resolution 2D-RARE MRCP in the diagnosis of pancreaticobiliary diseases. MATERIALS AND METHODS: 23 patients with various pancreaticobiliary diseases were evaluated using conventional and high-resolution 2D-RARE sequences. RESULTS: High-resolution RARE MRCP allowed for improved delineation of biliary and pancreatic ducts at the expense of reduced signal-to-noise ratio. Pathological findings were significantly (p < 0.001) better demonstrated with high resolution RARE MRCP (score 1.65 +/- 0.54) as compared to the conventional RARE sequence (score 2.58 +/- 0.62). CONCLUSIONS: High-resolution 2D-RARE-MRCP improves the delineation of biliary and pancreatic ducts. This sequence should replace the conventional 2D-RARE sequence.

Adult↗
PubMed1999

[Combined use of MRI and MR cholangiopancreatography and contrast enhanced dual phase 3-D MR angiography in diagnosis of pancreatic tumors: initial clinical results].

PURPOSE: To evaluate the accuracy of a non-invasive "all-in-one" staging MR method in patients with pancreatic tumors. MATERIAL AND METHODS: 46 patients were prospectively evaluated by a combined MR imaging protocol including breath-hold T1- and T2-weighted pulse sequence, MRCP using a breath-hold 2D-RARE sequence, and breath-hold gadolinium-enhanced dual-phase 3D-MR angiography. RESULTS: All pancreatic tumors were detected by the combination of cross-sectional imaging and MRCP. In spite of the use of MRCP, definitive differentiation between pancreatic carcinoma and chronic pancreatitis was not possible in 3 (6.5%) out of 46 cases. High quality 3D-MR angiograms were obtained in 43 (93.5%) cases. In 6 (13%) patients 3D-MRA showed an aberrant right hepatic artery. The overall accuracy of MRI in assessing extrapancreatic tumor spread, lymph node metastases, liver metastases, and vascular involvement was 95.7%, 80.4%, 93.5%, and 89.1%, respectively. CONCLUSION: Due to its high accuracy, the "all-in-one" MR protocol may become the most important modality after clinical examination and ultrasound in the diagnostic work-up for most patients with suspicion of pancreatic tumors.

Arteries↗
PubMed1998

A modification of the JAM test is necessary for a correct determination of apoptosis induced by FasL+ adherent tumor cells.

Tumor cells from several organs including colon have recently been shown to express Fas ligand (FasL) in vitro and in vivo. The expression, which in some tumours occurs de novo, was suggested to facilitate immune escape of malignant cells by killing tumor-infiltrating lymphocytes via Fas-FasL-induced apoptosis. An argument to support this hypothesis is the detection of tumor cell-induced apoptosis in Jurkat cells (as model T cells) by means of the widely used JAM test. In the present work the validity of this test for the analysis of colon carcinoma cell-mediated apoptosis in Jurkat cells was scrutinized in detail. The presented data show that the JAM test as described previously is prone to false-positive detection of apoptosis, when adherent epithelial cells are used as effectors. Furthermore, three lines of evidence indicated that several FasL+ colon carcinoma cell lines did not induce detectable apoptosis in Jurkat cells in vitro. We conclude that: (1) The JAM test must be modified for testing DNA fragmentation induced through adherent effector cells and (2) FasL+ colon carcinoma cells may be unable to induce apoptosis in vitro.

Apoptosis↗
PubMed1998

The effect of pentaerithrityl-tetranitrate on parameters of the microcirculation.

AIM OF THE STUDY: The effect of organic nitrates on microcirculation was first studied in 1964 and with regard to glyceroltrinitrate (GTN) an "internal hemodilution" (i.e. a fluid shift from the extravascular fluid to the intravascular compartment) was observed. Therefore, we found it of interest to study the effects of the long-acting PETN on parameters of hemorrheology. METHODS: The effects of single doses of 25, 50, and 80 mg PETN, 0.4 mg GTN, and of placebo were investigated on the capillary erythrocyte velocity (CEV; Capiflow), the tissue oxygen tension (tcpO2), the deformability of red blood cells, the plasma viscosity and of the fibrin content of the plasma in a single-blind, randomized study over 12 h in 12 healthy female and male volunteers. The CEV and the tcpO2 were measured in the nailfold of the fourth finger and on the skin of its end phalanx, respectively. Statistical analysis was performed by analysis of variance, the calculation of epsilon (Greenhouse-Geisser), and the multiple t test. RESULTS: After administration of 50 or 80 mg PETN the CEV decreased by 30% over a period of 2 or 4 h (p = 0.02 or 0.002). A decrease by 11% was measured 1 and 2 h after administration of GTN (p = 0.034). Under the same PETN doses tcpO2 increased from 1.41 to 1.78 mm mercury (p = 0.002). The deformability of red blood cells was slightly increased after 50 and 80 mg PETN under share rates of 60 Pa from 55.5 to 58.0% 8 and 12 h after intake. The plasma viscosity was decreased after intake of 50 mg PETN 4 to 8 h (1.36 vs. 1.34 Pa x s, p = 0.023) and after intake of 80 mg 2 to 12 h post dose (1.36 vs. 1.33 Pa x s, p = 0.015). The systolic or diastolic blood pressure decreased, but was not significant. CONCLUSIONS: The PETN-induced decrease in CEV can be explained with the pre- and afterload decreasing properties of the nitrates. The increase in tcpO2 and erythrocyte deformability and the decrease in viscosity are additional advantageous effects on the microcirculation. If the results are transferred from the nailfold of the finger to the myocardium, the benefit of nitrates could not only be seen in the decrease in preload due to their vasodilating properties, but also in improving the parameters of microcirculation. The internal hemodilution and the slightly enhanced deformability might provide an additional supply of myocardial capillaries in case of myocardial ischemia.

Administration, Oral↗
PubMed1997

[Effect of a local nonsteroidal anti-inflammatory drug on postoperative irritation after squint surgeries. Prospective randomized double-blind study].

BACKGROUND: Topical application of a nonsteroidal antiphlogistic drug (NSAD) is often recommended to minimize postoperative lid and conjunctival edema. However, the effectiveness of such therapy remains controversial. PATIENTS AND METHODS: The study presented included 100 patients aged 23.6 +/- 19.5 (5 to 77) years, who were randomly assigned to two treatment groups. Group 1 included 50 patients who underwent squint surgery, and who received Flurbiprofen ED twice a day from the first preoperative day to the third postoperative day. Group 2 served as a control group. These patients were treated with the same regimen using artificial tears. The extent of lid and conjunctival edema was assessed and scored from 1 to 4 on the fourth postoperative day. RESULTS: Squint surgery was performed on 129 eyes of 100 patients. In 32 eyes (24.8%) one muscle was operated on. In 79 eyes (61.2%) 2 muscles and in 18 eyes (14%) three muscles were operated on. The average postoperative conjunctival edema score was 2.08 +/- 0.62 (Flurbiprofen group) and 2.04 +/- 0.67 (control group), respectively. The scoring values for lid edema were 1.90 +/- 0.54 and 1.82 +/- 0.43. The differences between the two groups were not statistically significant (P = 0.21 and 0.39; Mann-Whitney test). No influence of the patient's age on the development of lid and conjunctival edema could be detected (P > 0.08). However, the number of muscles that were operated on had a significant influence on both parameters (P = 0.01 and 0.028). Single muscle operations revealed the lowest scaling values (P < 0.02 and P < 0.04). No difference was found whether 2 or 3 muscles were operated on (P = 0.24 and 0.12). CONCLUSIONS: No beneficial effect of topical application of NSAD on postoperative lid and conjunctival edema could be found in this controlled study.

Adolescent↗