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H Vogt

Publications and source records attributed to H Vogt.

At least 55 records · Page 3Linked to original sources
PubMed1994

Computer-assisted 3D reconstruction of the terminal branches of the cerebral arteries. I. Anterior cerebral artery.

We present a three-dimensional anatomical computer model of the terminal branches of the anterior cerebral artery, acquired from equidistant serial anatomical slices of three brains. The reconstructions provide a clear picture from all angles of the complicated course of the terminal branches of the cerebral arteries, which can help to identify them on conventional and magnetic resonance angiography. Our rendition of the cerebral arteries can also be matched with CT, MR or PET images to indicate the areas of extension of individual branches, allowing neuromorphological and functional correlations.

Adult↗
PubMed1994

Computer-assisted 3D reconstruction of the terminal branches of the cerebral arteries. II. Middle cerebral artery.

We present a three-dimensional anatomical computer model of the terminal branches of the middle cerebral artery, acquired from equidistant serial anatomical slices of three brains. The reconstructions provide a clear picture from all angles of the complicated course of the terminal branches of the cerebral arteries, which can help to identify them on conventional angiography and magnetic resonance angiography. The arteries can also be matched with CT, MR or PET images to indicate the areas of extension of individual branches, allowing neuromorphological and functional correlations.

Adult↗
PubMed1994

Computer-assisted 3D reconstruction of the terminal branches of the cerebral arteries. III. Posterior cerebral artery and circle of Willis.

We present a three-dimensional anatomical computer model of the terminal branches of the posterior cerebral artery and circle of Willis, acquired from equidistant serial anatomical slices of three brains. The reconstructions provide a clear picture from all angles of the complicated course of the terminal branches of the cerebral arteries. This can help to identify the arteries in conventional and magnetic resonance angiography. Our rendition of the cerebral arteries can be matched with CT, MR und PET images to indicate the areas of extension of the individual branches, allowing neuromorphological and functional correlations.

Basilar Artery↗
PubMed1993

Analysis of lymphocyte subsets in patients with aplastic anemia before and during immunosuppressive therapy.

To define the contribution of T-lymphocyte subsets in the development of aplastic anemia (AA), T-cell subpopulations including alpha beta T cells, gamma delta T cells, and delta TCS1-positive gamma delta T cells, were analyzed by cytophotometry in the peripheral blood (PB) and bone marrow (BM) of patients with AA before and after 6 weeks of therapy with anti-lymphocyte globulin (ALG), methylprednisolone, and cyclosporin A (CSA). In nine patients with AA a significant decrease of PB- and BM-derived T cells was observed after 6 weeks of therapy as compared with normal controls. At diagnosis, the CD4/CD8 ratio in PB and BM of the patients did not differ from the ratio in the control population; however, a reversed ratio (< 1) was present in PB as well as in BM after weeks of therapy. Interestingly, lymphocytes expressing the gamma delta T-cell receptor (TCR tau delta) were significantly decreased both before (PB 1.2 +/- 0.1%; BM 0.8 +/- 0.1%) and after 6 weeks of therapy (PB 0.7 +/- 0.1%; BM 0.7 +/- 0.1%) as compared with healthy controls (PB 2.4 +/- 0.2%; BM 2.3 +/- 0.2%). However, the proportion of the gamma delta-T-cell subpopulation expressing the delta TCS1 phenotype was markedly increased before (PB 42 +/- 3.5%; BM 31 +/- 3%) and especially after 42 days of therapy (PB 77 +/- 12%; BM 45 +/- 2%) as compared with that in normal subjects (PB 19 +/- 2%; BM 9.7 +/- 0.8%). At present, follow-up is under evaluation to correlate these findings with hematological response. The pathophysiological significance of the observed alterations within the T-cell subsets and especially the gamma delta T-cell populations will require further functional analyses, in particular since delta TCS1-positive gamma delta T cells exhibit autoimmunological capacity.

Anemia, Aplastic↗
PubMed1993

Characterization of membrane-bound and solubilized high-affinity binding sites for 5'-N-ethylcarboxamido[3H]adenosine from bovine cerebral cortex.

A high-affinity binding site for 5'-N-ethylcarboxamido[3H]adenosine ([3H]NECA) from bovine cerebral cortex has been characterized in its membrane-bound and solubilized state after gel filtration on Sepharose CL-6B. For detection of this site in membranes, it was necessary to remove metabolites with high affinities for this site enzymatically, e.g., adenosine by addition of adenosine deaminase and inosine by addition of nucleoside phosphorylase. The pore-forming peptide antibiotic alamethicin further enhanced binding of [3H]NECA to this site in membranes. In contrast to adenosine receptors and the adenotin-like low-affinity binding protein, this novel site was extremely sensitive against treatment with the sulfhydryl alkylating agent N-ethylmaleimide. In competition experiments, this site could be differentiated from adenosine receptors by its high affinity for adenine nucleotides and its lack of affinity for adenosine receptor antagonists. Inosine and its derivative S-(4-nitrobenzyl)-6-thioinosine were relatively potent ligands with Ki values in the high nano- and low micromolar range, respectively. We conclude that the high-affinity NECA binding site described previously in bovine striatum is not exclusively located in the striatum, but can also be detected in membrane preparations and soluble extracts of bovine brain cortex.

Adenosine↗
PubMed1993

Measurement of guanine nucleotide-binding protein activation by A1 adenosine receptor agonists in bovine brain membranes: stimulation of guanosine-5'-O-(3-[35S]thio)triphosphate binding.

Signal transduction by A1 adenosine receptors was investigated by measuring the modulation by adenosine agonists of guanosine-5'-O-(3-[35S]thio)triphosphate ([35S]GTP[S]) binding to guanine nucleotide-binding proteins (G proteins). The extent of stimulation of [35S]GTP[S] binding was dependent on the presence of high concentrations of Mg2+ (1-10 mM), GDP (10 microM), and NaCl (100 mM). Under optimal conditions, the agonist (R)-N6-phenylisopropyladenosine [(R)-PIA] stimulated binding of [35S]GTP[S] to G proteins approximately 2.3-fold. All adenosine receptor agonists tested stimulated the binding of [35S]GTP[S] with a rank order of potency typical of A1 adenosine receptors in bovine tissues, (R)-PIA > 2-chloro-N6-cyclopentyladenosine > (S)-PIA > 5'-N-ethylcarboxamidoadenosine > 2-[4-(2-carboxyethyl)phenethylamino]-5'-N-ethylcarboxamidoadenosin e. The EC50 values for G protein activation correlated with the Ki value of agonists for inhibition of radioligand binding to the high affinity state of the A1 adenosine receptor. The inclusion of 100 mM NaCl as well as increasing GDP concentrations led to a parallel increase of Ki values and EC50 values. In addition, both compounds induced a shift of A1 adenosine receptors from the high affinity state for agonists to the low affinity state.

Animals↗
PubMed1992

Identification of a novel high affinity adenosine binding protein from bovine striatum.

In solubilized extracts from bovine striatal membranes three different binding sites for 5'-N-ethylcarboxamidoadenosine ([3H]NECA) were observed after separation of the extract by gel filtration on Sepharose CL-6B. The first peak was eluted in the void volume and contained the A2 adenosine receptor. In the second peak, [3H]NECA binding sites were eluted with a pharmacological profile characteristic of adenotin, a low affinity non-receptor adenosine binding protein. The third peak represented approximately 50% of the [3H]NECA binding activity. This site bound [3H]NECA in a reversible and saturable manner with KD of 17 nmol/l and a binding capacity of 11.3 pmol/mg protein. In competition experiments, adenosine, NECA, NAD, inosine, 5'-AMP and S-adenosyl-L-homocysteine were the most potent ligands. In contrast to adenosine receptors, this site did neither bind adenosine receptor antagonists nor the A2 selective agonist CGS 21,680 (2-[p-(2-carboxyethyl)phenethylamino]5'-N-ethylcarboxamidoadeno sin e). These results suggest the existence of a novel high affinity binding site for adenosine of unknown function in bovine striatum.

Adenosine↗
PubMed1992

Computer-assisted 3D-reconstruction and statistics of the limbic system. 2. Spatial statistics of the hippocampal formation, the fornix, and the mammillary bodies.

A statistical method is described to show the distribution of neuroanatomical structures within a Cartesian coordinate system from any given number of examinations. The algorithm is based on polygons derived from the outlines of neuroanatomical structures in parallel canthomeatal-orientated cutting planes. These polygons are transformed in virtual voxels, rotated into the bicommissural coordinate system, and projected onto the three main planes of this coordinate system. Areas with the same probability for the structures examined are given in these planes. As an example this method is applied to the hippocampal formation and the results attained are shown.

Hippocampus↗
PubMed1991

The distribution of restriction fragment lengths for non-overlapping restriction sites in a random DNA sequence model.

Overlapping subsequences in a DNA sequence are not independent even if independence is supposed for the single nucleotides. Therefore the often used geometric distribution for the length of restriction fragments is not exact. The exact distribution of this random variable is derived for non-overlapping restriction sites in a DNA sequence with an infinite (or very large) number of nucleotides. Correction to the finite case is easy. It is shown that the simple geometric distribution is a good approximation as long as the basic probability for the occurrence of the recognition sequence at a given site is small.

Base Sequence↗
PubMed1991

[Human parvovirus B19 as the cause of aplastic crisis in hereditary spherocytosis].

A seven months old boy was admitted to hospital for investigation and treatment of severe anaemia. The final diagnosis was hereditary spherocytosis. When, six weeks later, he developed an aplastic crisis, serological criteria provided evidence of recent human parvovirus B19 infection. The same disease was detected in the family. Human parvovirus B19 is shown to be of particular interest in aplastic crisis.

Anemia, Aplastic↗
PubMed1991

Comparison of A1 adenosine receptors in brain from different species by radioligand binding and photoaffinity labelling.

Radioligand binding to A1 adenosine receptors at brain membranes from seven species was investigated. The antagonist 8-cyclopentyl-1,3-[3H]dipropylxanthine ([3H]DPCPX) bound with affinities between 0.17 nM in sheep brain and 2.1 nM in guinea pig brain. Competition of several antagonists for [3H]DPCPX binding showed that the most potent compounds were DPCPX with Ki values of 0.05 nM in bovine brain and 1.1 nM in guinea pig brain and xanthine amine congener (XAC) with Ki values of 0.03 nM in bovine brain and 5.5 nM in guinea pig brain. The differences in affinity of the agonist radioligand 2-chloro-N6-[3H]cyclopentyl-adenosine ([3H]CCPA) were less pronounced, ranging from a KD value of 0.12 nM (hamster brain) to 0.42 nM (guinea pig brain). Agonist competition for [3H]DPCPX binding of photoaffinity labelling, however, exhibited marked species differences. N-Ethylcarboxamidoadenosine (NECA) and S-N6-phenylisopropyladenosine (S-PIA) showed 20 to 25-fold different KD values in different species. NECA had a particularly high affinity in guinea pig brain and was only two-fold less potent than R-PIA. Thus, the difference from the "classical" A1 receptor profile (R-PIA greater than -NECA greater than S-PIA) is not sufficient to speculate that A1 receptor subtypes may exist that are coupled to different effector systems. Our data show that these difference can easily be explained by species differences.

Affinity Labels↗
PubMed1991

Diagnosis of paroxysmal nocturnal haemoglobinuria using immunophenotyping of peripheral blood cells.

Paroxysmal nocturnal haemoglobinuria (PNH) is now generally accepted as a disease in which bone marrow derived cells are deficient in phosphatidylinositolglycan (PIG)-anchored surface molecules. A series of new monoclonal antibodies detecting PIG-anchored surface structures on human leucocytes (CD48, CD55, CD59) has recently been described. In the present study 12 patients with the diagnosis PNH and a positive Ham test were examined for PIG-anchored surface antigen expression on various cell lineages using immunofluorescence. In all patients deficient cells were detected in erythrocyte, granulocyte and monocyte analysis. A deficient lymphocyte subset was also observed in all but one of these patients. Using two-colour analysis, all lymphocyte subpopulations such as T, B and NK cells were found to be affected. In addition, peripheral blood cells of 22 patients with severe aplastic anaemia (SAA) were tested for the PIG-anchoring defect. In five of these patients the defect was detected, and in four of the five the lack of PIG-anchored molecules was confined to the granulocyte and monocyte lineages apparently without affecting the erythrocytes. The results of these studies demonstrate that cytofluorographic testing of peripheral blood cells provides a simple and reliable method for establishing the diagnosis of PNH. Furthermore, especially in the case of aplastic anaemia patients, the sensitivity of immunophenotyping might be superior to conventional laboratory tests.

Anemia, Aplastic↗
PubMed1991

[Occurrence of salmonellas in lakes and rivers and drinking water of southern Bavaria].

Salmonella could be isolated from nine of 596 samples from lakes and from 195 of 1,549 river water samples from South Bavaria between 1986 and 1990. In correlation with the classification of bathing waters the Salmonella occurrence ranged from 0.3% to 2.9% and 4.3% in lakes and from 1.0% to 7.8% and 23.8% in rivers with regard to water samples which were satisfactory or which were not satisfactory in respect of the guide values and the limit values as determined by the densities of faecal coliforms and total coliforms. In these studies it was seen for the first time that Salmonella enteritidis exceeded Salmonella typhimurium in frequency in 1988, increasing to 63.5% of Salmonella-positive surface water samples in 1990. Salmonella could also be isolated from six of 132 drinking water samples containing Escherichia coli as well and from three of 129 drinking water samples containing coliforms.

Colony Count, Microbial↗
PubMed1991

[Three-dimensional reconstructions in neuroanatomy].

Computer-aided 3D reconstructions of neurofunctional systems and structures are generated as a reference for neuroimaging (CT, MRI, PET). The clinical application of these 3D reconstructions requires a coordinate system and conditions resembling the intravital neuroanatomy as far as possible. In this paper the neuroanatomical Reference System (NeuRef) of the Department of Neuroanatomy of Hannover Medical School is presented. This consists of methods to record brain structures from serial sections with minimal error (less than 1 mm) and to display 3D brain models derived from such a data base. In addition, NeuRef is able to generate sections through, for instance, the visual and pyramidal system and to transfer these data onto a corresponding CT image. Therefore, this method can serve as a diagnostic aid in neuroradiology, in operation planning, and radiotherapy. It can also be used in PACS.

Brain↗
PubMed1990

[Accidental poisoning in children].

A retrospective study was carried out among children admitted to the Pediatric Clinic, Haukeland Hospital, from 1958 until 1986 for accidental poisoning. Drugs was the most frequent poisoning agent (49%), followed by household agents (22%), different agents (20%) and plants/mushrooms (9%). 89% of the children were under five years of age, 57% were boys. 20% stayed more than one day in the hospital. Very serious poisonings involving admission for more than 14 days were most frequently seen after intake of drugs. The number of admissions was doubled from 1966-70 to 1981-85. Most of the increase referred to poisoning from plants, tobacco and hydrocarbon products. The greatest increase was found for admissions lasting less than two days. Most of the potentially serious poisonings in our study were caused by agents that, by American or British law, it would have been illegal to sell without special child-resistant packaging. It is strongly advised that a similar law be passed in Norway.

Accidents, Home↗
PubMed1989

[Disorders of language and cognition in schizophrenic patients and their effect on communication].

The subjects of this study are disturbances of concept formation in schizophrenics and the influence of that disorder on communication. The verbal coding and recognition of colours of a group of chronic schizophrenics and their normal controls were investigated. In describing the colours, the schizophrenics showed less variability, lower utterance lengths, and shorter reaction times for coding. These symptoms were interpreted as an indication that the schizophrenics don't realize the complexity of the task and differentiate less between the different descriptions (over inclusion). This higher stereotypy contradicts the suggested higher creativity of schizophrenics. No difference was found between the coding of schizophrenics and that of normals in communication with normals. However the schizophrenics showed a deficit of decoding. This was also interpreted as an indication of enlarged concepts within the meaning of the conception of "over inclusion".

Adult↗