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Biomedical subjects

E Keller

Publications and source records attributed to E Keller.

At least 163 records · Page 9Linked to original sources
PubMed1996

[Advantages of lymph node staging in 872 stomach carcinoma patients].

The German Stomach Cancer TNM Study Group registered 1444 patients from 1982 to 1984 in a multicenter observational study to validate the tumor node metastasis stage groupings. The follow-up-rate in 1989 was 99.4%. Among others the pattern of lymph node metastases and the benefit of systematic lymphadenectomy (SLA) was studied. 872 patients had a resection with or without lymph node staging lymph node metastases were under- or overestimated intraoperatively in 7-23%. More than expected lymph nodes distant from the primary were involved. The survival rate of patients with resected tumors in the distal third of the stomach could be evaluated. We found statistically significant benefit for stage I (UICC 1987) of patients resected with SLA vs. without: 86% respectively 66%. The conclusions are as follows: lymph node involvement is numerous, widespread and also far away from the tumor. The intraoperative statements about lymph node metastases are doubtful. The R0-resection includes the SLA which is improving the survival rate for stage I.

Germany↗
PubMed1995

Pvu II polymorphism in the primate homologue of the mouse B144 (LST-1). A novel marker gene within the tumor necrosis factor region.

A Pvu II RFLP was mapped within the LST-1 gene, the human homologue of the mouse B144 sequence, establishing LST-1 as a new marker gene within the TNF region. We investigated the distribution of this Pvu II RFLP in 274 unrelated individuals, 132 additional HLA-DR7-positive individuals, 86 homozygous lymphoblastoid cell lines, and in four families. Seventeen of 274 individuals (6.2%) were heterozygous for the Pvu II restriction site (ADB1 = lack and ADB2 = presence of the Pvu II restriction site). In our study population the polymorphism has a much wider distribution than that previously reported in an analysis of selected haplotypes. Besides a strong association of ADB1 with HLA-B14, -DR7, we found a further association with HLA-B35. These results were also validated by family segregation studies and analyses of homozygous cell lines. In addition, five of 17 individuals carrying the ADB1 allele had HLA types other than B14 or B35, emphasizing that the presence of ADB1 is not limited to the HLA-B14, DR7 haplotype. LST-1 and its polymorphism may be used as an additional marker of the TNF region, where genes responsible for autoimmune diseases are suspected to be localized.

Alleles↗
PubMed1995

Identification of two major HLA-B44 subtypes and a novel B44 sequence (B*4404). Oligotyping and solid phase sequencing of polymerase chain reaction products.

PCR-based analyses were performed for the identification of HLA-B44 subgroups. Genomic DNA from six homozygous cell lines and 44 healthy individuals who had serologically tested positive for HLA-B44 was investigated for polymorphism in exons 2 and 3 of the HLA-B44 genes. Two primers were designed for specific amplification of the B*4401 allele in exon 2. None of the tested genomic DNAs, including the cell line "BAU-J" from which the sequence of B*4401 was derived, was amplified successfully using these primers, indicating that the B*4401 sequence may not be correct in position 242-244. For identification of the B*4402 and *4403 subtypes we specifically amplified the B44 gene in exon 3 using two sequence-specific primers. The PCR products, which were obtained from all B44-positive samples (n = 50) and from none of the B44-negative controls (n = 20), were subsequently hybridized with the dig-ddUTP-labeled oligonucleotides. The base substitution at position 146, as described previously for B*4401 and *4402 (C for G), could not be confirmed by oligonucleotide hybridization. In contrast, the oligonucleotide typing for G in position 146 gave positive signals in all B44-positive samples. Except for one, HLA-B44-positive DNAs from LCLs and healthy individuals could be divided into two subgroups according to the polymorphic region in position 195-197. Out of 44 unrelated individuals with B44, 27 (61%) were positive for B*4402 and 16 (36%) were positive for B*4403.(ABSTRACT TRUNCATED AT 250 WORDS)

Alleles↗
PubMed1995

Decreased inotropic response to beta-adrenergic stimulation and normal sarcoplasmic reticulum calcium stores in the spontaneously hypertensive rat heart.

Cardiac hypertrophy in the spontaneously hypertensive rat has been shown to be accompanied by a diminished inotropic response to beta-adrenergic stimulation. This diminished response has been attributed to abnormalities in various components of the beta-adrenergic signaling system. There is also evidence that regulation of intracellular Ca2+ cycling may be altered in the hypertrophied heart of the spontaneously hypertensive rat. We proposed that the diminished response to beta-adrenergic stimulation may reflect abnormalities in Ca2+ cycling, specifically alterations in the ability of the sarcoplasmic reticulum to effectively release and resequester Ca2+. We have used the unique combination of functional measurements on isolated, isometrically contracting papillary muscles from hearts of 26-week-old spontaneously hypertensive rats and their Wistar-Kyoto controls, together with electron probe microanalysis measurements of sarcoplasmic reticulum Ca2+ content in the same muscles after rapid freezing, to determine the availability of Ca2+ for activation of contraction, following beta-adrenergic stimulation. We observed a significant decrease in the inotropic response to beta-adrenergic stimulation in papillary muscles from the spontaneously hypertensive rats, as compared with Wistar-Kyoto controls, however in these same muscles, frozen during relaxation, there was no evidence of an accompanying decrease in the size of the sarcoplasmic reticulum Ca2+ store. In an additional group of muscles which were frozen during contraction, the amount of Ca2+ remaining in the sarcoplasmic reticulum after stimulated release was also not different in the two strains. These results indicate that the decreased inotropic response to beta-adrenergic stimulation in hypertrophied hearts of the spontaneously hypertensive rat is unlikely to be due to decreased availability of Ca2+ for activation of contraction. Additionally, to determine whether there is intracellular Ca2+ overload in the cardiac muscle cells of hearts of spontaneously hypertensive rats, we measured the amount of Ca2+ in mitochondrial and at the level of the myofilaments by electron probe microanalysis. These results indicate that intracellular Ca2+ overload does not accompany cardiac hypertrophy in the spontaneously hypertensive rat. This study therefore shows no correlation between altered intracellular Ca2+ cycling and the decreased inotropic response to isoproterenol in the spontaneously hypertensive rat at 26 weeks of age.

Actin Cytoskeleton↗
PubMed1995

Expansins in growing tomato leaves.

An expansin-like protein from growing tomato leaves was identified by its ability to restore the 'acid-growth' response to heat-inactivated tomato walls and by its similarity to expansins from cucumber hypocotyls. Native walls from growing tomato leaves exhibit an endogenous acid-induced extension (creep) that resembles in various biochemical characteristics the acid-growth activity of cucumber hypocotyls. For example, the acid-growth activity is lost when the walls of tomato leaves are briefly heated and is largely restored by addition of a crude protein extract from the walls of growing leaves. Wall proteins from growing leaves enhance the stress relaxation spectrum of tomato walls in a fashion characteristic of cucumber expansins. HPLC fractionation of the crude wall protein from tomato leaves yielded an active fraction containing a major 27 kDa protein that cross-reacts with an antibody raised against cucumber expansin. The results show that tomato leafwalls possess at least one expansin that is responsible for the acid-growth property of leaves and indicate that cell wall extension in leaves shares an underlying protein mechanism common to cell wall expansion in stems.

Cell Division↗
PubMed1995

Regulation of growth hormone (GH), insulin-like growth factor (IGF)I, IGF binding proteins -1, -2, -3 and GH binding protein during progression of liver cirrhosis.

The aim of this study was to investigate the regulation of various proteins of the GHIGF axis during progression of liver failure and to search for potential prognostic markers of functional hepatic reserve. Serum levels of growth hormone (GH) and high affinity growth hormone binding protein (GHBP), insulin-like growth factor I (IGF-I) and IGF binding proteins (IGFBP) -1, -2 and -3 were determined in patients with liver cirrhosis. A continuous decline in the concentrations of IGF-I, IGFBP-3 and serum GH-binding activity (GHBP) was observed during progression of cirrhosis and the data correlated significantly with choline esterase, total serum protein and the Child score. In addition, GHBP showed a significant correlation with the enzymatic activity of glutamate dehydrogenase or transaminases and seems so to be influenced by the degree of liver cell damage. In contrast, IGFBP-1 and IGFBP-2 levels were significantly elevated in preterminal disease suggesting an upregulatory mechanism is still effective in this situation. Only when liver function had markedly deteriorated, the serum levels of these two parameters decreased again, possibly due to an impaired synthesis. The excellent correlation between the serum levels of IGF-I (r = -0.64, p < 0.001) or IGFBP-3 (r = -0.67, p < 0.001) and the Child score index suggests that they reflect the hepatic functions just as conventional indicators. For an appropriate interpretation of the liver function the measurement of the growth related peptides can be a valuable tool to estimate pathological alteration in the functional hepatic reserve or in the glucose homeostasis.

Adolescent↗
PubMed1995

[Spiral computerized tomography, multiplane transesophageal echocardiography and magnetic resonance imaging in the diagnosis of thoracic aortic dissection].

The aim of this study was the evaluation of spiral computed tomography (Spiral-CT), multiplane transesophageal echocardiography (multiplane TEE) and magnetic resonance imaging (MRI) in the diagnosis of thoracic aortic dissection. 41 patients were examined: 30 with clinically suspected acute aortic dissection (14 Stanford A, 7 Stanford B), 11 with aortic repair (7/11 with persisting distal dissection). In 14 patients there was involvement of the supraaortic vessels. Sensitivity of Spiral-CT, multiplane TEE and MRI in the detection of aortic dissection was 100%, specificity was 100, 92, and 91%. In the assessment of involvement of aortic arch vessels sensitivity was 100, 67, and 60%, specificity was 100, 95, and 90%. The new imaging modalities Spiral-CT and multiplane TEE are equal to MRI in the detection of aortic dissection. In the assessment of the supraaortic branches Spiral-CT is superior to multiplane TEE and MRI and might become the method of choice.

Adult↗
PubMed1995

[Value of turbo-spin-echo sequences in cerebral magnetic resonance tomography in children].

AIM: The value of turbo-spin-echo (TSE) sequences was compared with conventional spin-echo (SE) and inversion-recovery (IR) sequences for cerebral MRT in 70 children at 0.5 T and 1.5 T. In addition we evaluated whether proton weighted sequences (PD) were diagnostically important and in what proportion of cases. METHOD: Conventional T1 and T2 weighted SE and T2 weighted TSE sequences were used in all children. An IR sequence was performed in 39 patients. The various sequences were analysed semiquantitatively with regard to image quality, artifacts and the demonstration of normal and anatomical structures and pathological findings. RESULTS: By any criteria, TSE sequences were superior to conventional T2 weighted SE sequences at 0.5T and 1.5 T, requiring a shorter examination time (35-53%). In 8.6% the pathological finding was best seen on PD-SE sequences (5 glial scars, 1 tumor). CONCLUSION: Although TSE sequences are better than T2 SE sequences with regard to image quality and the demonstration of abnormalities, conventional double-echo SE sequences (with PD and T2 weighted images) cannot be entirely replaced by T2 weighted TSE sequences in children.

Adolescent↗
PubMed1995

[Possibilities and limitations of color duplex guided compression therapy of puncture-induced blood vessel lesions in the groin].

AIM: Colour Doppler imaging (CDI) is a useful tool for non-invasive diagnosis and treatment of postcatheterisation lesions of the femoral artery. The aim of the present study was to evaluate success and limitations of the method in unselected patients. MATERIAL AND METHODS: A total of 29 patients, including 24 patients with pseudoaneurysms and 5 patients with arteriovenous fistulas, were treated by CDI-guided compression therapy. RESULTS: 17 of 24 (71%) pseudoaneurysms, but only 1 of 5 (20%) arteriovenous fistulas were successfully occluded. Successful treatment of pseudoaneurysms was limited by continuous anticoagulation and local pain during compression. However, arteriovenous fistulas, except one, could not be occluded due to high flow velocities in the shunt. CONCLUSION: CDI-guided compression therapy is the treatment of choice for postcatheterisation pseudoaneurysms, while arteriovenous fistulas should be repaired surgically. If possible, anticoagulation therapy should be discontinued and analgesic drugs should be prescribed.

Adult↗
PubMed1995

[1H-MR spectroscopic imaging in patients with clinically diagnosed Alzheimer's disease].

PURPOSE: To detect regional differences in accompanying metabolic changes, 1H-Magnetic Resonance Spectroscopic Imaging (MRSI) was performed in 16 patients with Alzheimer's disease (AD); the clinical diagnosis was based upon DSM-III-R and NINCDS-ADRDA guidelines. METHODS: In the hippocampal region metabolic maps of the local distribution of N-acetylaspartate (NAA), choline (Cho), creatine compounds (P(Cr)) and lactate were determined. Ratios of Cho/NAA, (P)Cr/NAA and Cho/(P)Cr calculated from selected hippocampal spectra were compared to those from healthy volunteers (n = 17). RESULTS: AD patients demonstrated an increase of Cho/NAA and (P)Cr/NAA ratios caused by increased choline compounds and decreased NAA. These alterations were observed in 11/12 cases in the hippocampal and in 7/12 in the temporo-occipital region. Hippocampal Cho/NAA ratios (0.56 +/- 0.19) were significantly elevated compared with controls (0.33 +/- 0.04; p < 0.0001). CONCLUSION: The observed elevation of choline compounds in the hippocampus supports the hypothesis that alterations in the cholinergic system play an important role in Alzheimer's disease. The observed reduction of NAA is due to neuronal degeneration.

Aged↗
PubMed1995

[Value of Turbo-FLAIR sequence in the diagnosis of brain diseases at 0.5 tesla].

PURPOSE: Aim of the study was to evaluate FLAIR combined with Turbo-Spin-Echo (Turbo-FLAIR) at 0.5 tesla in comparison to conventional T1- and T2-weighted spin-echo images (SE) in MRI of the brain. MATERIAL AND METHODS: A Turbo-FLAIR sequence was optimised for 0.5 Tesla (Philips Gyroscan T5-II) that provided seventeen 5 mm sections in 4:21 minutes (TR = 6075 ms, T1 = 1600 ms, TE = 120 ms and a turbofactor = 17). Images were compared with T1- (TR = 500 ms, TE = 15 ms) proton density and T2-weighted spin-echo (TR = 2500 ms, TE = 20/90 ms) studies in 10 healthy volunteers and 30 patients with various brain pathologies. RESULTS: Turbo-FLAIR could effectively eliminate the CSF signal in all studies except ventricular areas with CSF inflow. Contrast-to-noise ratios (C/N) for the contrast between lesions and CSF was superior in Turbo-FLAIR. C/N between lesions and grey matter was significantly higher in Turbo-FLAIR than in proton density (PD)-weighted SE. C/N between lesions and white matter was equal to PD-weighted SE but significantly smaller than on T2-weighted SE. Visual analysis showed greater lesions conspicuity with Turbo-FLAIR and a higher frequency of detection of cortical and subcortical lesions. CONCLUSIONS: Turbo-FLAIR is a reliable and practical technique on 0.5 Tesla, that is more sensitive than SE sequences especially for the detection of cortical, subcortical lesions and lesions surrounded by CSF.

Adolescent↗
PubMed1995

[Multimodal carotid occlusion test for determining risk of infarct before therapeutic internal carotid artery occlusion].

UNLABELLED: In patients with head and neck carcinoma and extensive cervical metastasis, the topographic and functional relationship of the tumor to the carotid artery is highly important. In case of suspected carotid infiltration, the possibility of a carotid resection or a prosthetic replacement has to be considered preoperatively. Treatment of cavernous carotid aneurysms may also require sacrificing the internal carotid artery (ICA). An interdisciplinary test occlusion of the ICA was performed to assess cerebral collateral circulation prior to permanent carotid occlusion. MATERIALS AND METHODS: Fifty-two patients with cervical tumors (n = 45) or inoperable aneurysms (n = 7) were examined. The endovascular balloon test occlusion (BTO) of the ICA was combined with monitoring of the neurological status, cardiovascular status (EKG, blood pressure), cortical function (EEG), and single photon emission CT (SPECT) imaging of the regional cerebral blood flow (rCBF) with 99mTechnetium-HMPAO. In the last 24 patients, transcranial Doppler sonography (TCD) of the ipsilateral middle cerebral artery (MCA) was added for direct hemodynamic monitoring during BTO. In order to improve the diagnostic value of the test results and to simulate hemodynamic crisis, the cerebrovascular reserve capacity was then evaluated with acetazolamide (Diamox). RESULTS: BTO could be performed without neurological complications or carotid dissection. In eight (15%) patients BTO had to be interrupted previously due to neurological symptoms or a delta-EEG. These patients and patients with highly pathological test results in SPECT imaging (n = 9) or TCD (n = 3) were excluded from permanent carotid occlusion. Ten (19%) patients were definitely occluded without hemodynamic complications, but two patients suffered embolic infarctions, which can not be predicted by this procedure. In two patients with a severe hypoperfusion in SPECT imaging, the ICA had to be ligated under emergency conditions following a carotid rupture. Predictably, a hemodynamic infarction occurred postoperatively in both patients. CONCLUSIONS: The multimodal BTO with brain perfusion imaging (HMPAO-SPECT) and quantitative blood flow monitoring (TCD) allows a hemodynamic stroke risk assessment prior to permanent occlusion of the ICA. The procedure is important for planning of the therapeutic strategy and for the preoperative dialogue with the patient. Embolic ischemic complications can not be predicted.

Adult↗
PubMed1995

Altered subcellular Ca2+ regulation in papillary muscles from cardiomyopathic hamster hearts.

To investigate whether cardiac dysfunction in prefailure cardiomyopathic (CM) hamster hearts is due to Ca2+ overload or alternatively to decreased availability of Ca2+ in the sarcoplasmic reticulum (SR), the Ca2+ channel agonist, BAY K 8644, was used to compare the effects of increased Ca2+ influx on function and subcellular Ca2+ distribution in papillary muscles from hearts of 110-day-old CM and normal hamsters. A band, mitochondrial, and junctional SR Ca2+ were measured by electron probe microanalysis in CM and normal papillary muscles, which were either untreated or pretreated with BAY K 8644. Muscles were then rapidly frozen during contraction or relaxation. The results showed decreased tension development and decreased inotropic response to BAY K 8644 in CM muscles versus normals. There was no elevation of mitochondrial or A-band Ca2+ in BAY K 8644-treated or untreated CM muscles frozen during contraction or relaxation compared with similarly treated normals. In muscles frozen during relaxation, junctional SR Ca2+ was lower in both untreated and BAY K 8644-treated CM muscles versus comparably treated normals. These results do not support the hypothesis of an increased sensitivity to Ca2+ in hypertrophied, prefailure CM hearts but do indicate that less Ca2+ is available in the SR for activation of contraction.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMed1995

Growth hormone-binding protein-related immunoreactivity in the serum of patients with acromegaly is regulated inversely by growth hormone concentration.

In this report we describe a newly developed radioimmunoassay (RIA) for the determination of the high-affinity growth hormone-binding protein (GHBP) in human blood. Using this RIA for the measurement of GHBP in serum of 29 patients with acromegaly, decreased concentrations were found compared to the normal range, depending on the activity of the disease. Growth hormone-binding protein was correlated inversely to log GH (r = -0.7, p < 0.001). A weaker relationship was shown between the GHBP activity determined in a functional assay based on charcoal separation and log GH (r = -0.51, p < 0.01). While insulin-like growth factor I (IGF-I) and IGF binding protein 3 (IGFBP-3) were correlated directly to log GH (r = 0.77 and r = 0.66, p < 0.001), an inverse and weaker relationship was evident between GHBP measured by RIA and IGF-I or IGFBP-3 (r = -0.61 and r = -0.57, p < 0.01). In contrast, no correlation could be detected between data of the functional GHBP assay and IGF-I or IGFBP-3.(ABSTRACT TRUNCATED AT 250 WORDS)

Acromegaly↗