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Biomedical subjects

A Horst

Publications and source records attributed to A Horst.

At least 19 recordsLinked to original sources
PubMed2004

A novel reconstruction algorithm to extend the CT scan field-of-view.

For various reasons, a projection dataset acquired on a computed tomography (CT) scanner can be truncated. That is, a portion of the scanned object is positioned outside the scan field-of-view (SFOV) and the line integrals corresponding to those regions are not measured. A projection truncation problem causes imaging artifacts that lead to suboptimal image quality. In this paper, we propose a reconstruction algorithm that enables an adequate estimation of the projection outside the SFOV. We make use of the fact that the total attenuation of each ideal projection in a parallel sampling geometry remains constant over views. We use the magnitudes and slopes of the projection samples at the location of truncation to estimate water cylinders that can best fit to the projection data outside the SFOV. To improve the robustness of the algorithm, continuity constraints are placed on the fitting parameters. Extensive phantom and patient experiments were conducted to test the robustness and accuracy of the proposed algorithm.

Algorithms↗
PubMed2002

Detection and characterization of plasma cells in peripheral blood: correlation of IgE+ plasma cell frequency with IgE serum titre.

In atopic patients and patients with hyper-IgE syndrome (HIE) highly elevated IgE serum levels can be detected. Due to their very low frequency little is known about IgE-producing plasma cells (PC) in peripheral blood. We used CD138 MACS microbeads to enrich plasma cells from peripheral blood of normal donors, atopic patients and one HIE patient. CD138+ cells were mainly CD45+, CD44++, CD19dim, CD38++, CD27++, CD86+, HLA-DR+/++, CD71dim, VLA-4+, VLA-5-, CD28-, CD25-, CD69-, CLA-, CD20-, CD21- and CD22-. They show weak expression of surface Ig but high levels of intracellular Ig and they secrete Ig in culture. Thus CD138+ cells from peripheral blood show characteristics of early plasma cells. IgE+ CD138+ plasma cells could be detected in 19 of 24 normal donors with an average frequency of 0.06% IgE+ cells among CD138+ cells. Higher frequencies were detected in atopic patients, atopic patients with markedly elevated serum IgE levels and the hyper-IgE patient with an average of 0.32%, 7.21% and 6.54%, respectively. Additionally, using the recently developed cellular affinity matrix technology, we were able to detect IgE secreting plasma cells and thereby could demonstrate that most of the IgE secreting cells express CD138. The frequency of IgE+ CD138+ cells among PBMC correlated highly significantly with serum IgE titres (r = 0.8532***), indicating that IgE secreting CD138+ cells in peripheral blood are directly related to the plasma cell pool contributing to the IgE titre.

Antibody Affinity↗
PubMed2001

Needs for mental health care and service provision in single homeless people.

BACKGROUND: Specific problems in sampling methodology, case-finding strategies and a standardised needs assessment in mentally ill homeless people have contributed to their being neglected as a mental health care clientele. METHOD: We assessed a representative sample of homeless people (n=102) in the highly industrialised city of Mannheim (Germany) regarding their prevalence of mental disorders (using the SCID) and their needs for mental health care (using the NCA). RESULTS: We found high prevalences, with 68.6% of all assessed homeless persons having a current mental disorder. Thus, needs for mental health care were very common, with unmet needs predominating in all problem areas, which was supported by a very weak service utilization. Thus, even in a region with a comprehensive community mental health care network, like the study area, mentally ill homeless people are widely under-provided. CONCLUSIONS: Results suggest that the traditional shelter system for homeless people carries most of the mental health care burden for their clientele and must be supported by adequate interventions from community-based mental health care services. A closer connection of both sectors and a better co-ordination of the care offers seems to be a prerequisite for helping to reduce unmet mental health care needs in this specific high-risk group.

Adolescent↗
PubMed2001

[How do mentally ill homeless persons evaluate their quality of life].

Besides pronounced deficiencies in psychiatric research concerning homeless mentally ill in Germany, studies concerned with the quality of life of homeless mentally ill were missing until now. This study reveals in a representative sample of 102 homeless people from the City of Mannheim, Germany that--compared to the homeless without psychiatric disorders of the sample--the mentally ill homeless (prevalence 68.6%) have significantly different subjective views of their quality of life regarding the items "state of health", "physical capabilities" and "support from others". The differences were even stronger if the homeless mentally ill were compared to a group of non-homeless mentally ill schizophrenic patients (n = 104), cared for in the City's well-equipped community care services. Community care patients reported a significantly better quality of life in respect of 11 items. These results were seen as a success of the concept of community-based mental health care. The consequences for improving care strategies for homeless mentally ill are discussed.

Activities of Daily Living↗
PubMed2001

Integrative efforts in occupational safety and health in the European union.

The European Union has had a long tradition in developing a common European social policy from its beginning. A milestone to European social policy in the field of occupational safety and health was the Single European Act in 1986. With this Single European Act the improvement of the work environment became an explicit objective of the community. Since that starting point several legislative and nonlegislative actions have been taken to face the huge challenges of globalisation with a targeted social policy. The aim of this policy is to reconcile the interests of the employers in productive and competitive workplaces with the interests of the employees in healthy working conditions.

Employment↗
PubMed2000

CEA-related cell adhesion molecule 1: a potent angiogenic factor and a major effector of vascular endothelial growth factor.

CEA-related cell adhesion molecule 1 (CEACAM1) exhibits angiogenic properties in in vitro and in vivo angiogenesis assays. CEACAM1 purified from granulocytes and endothelial cell media as well as recombinant CEACAM1 expressed in HEK293 cells stimulate proliferation, chemotaxis, and capillary-like tube formation of human microvascular endothelial cells. They increase vascularization of chick chorioallantoic membrane and potentiate the effects of vascular endothelial growth factor (VEGF)165. VEGF165 increases CEACAM1 expression both on the mRNA and the protein level. VEGF165-induced endothelial tube formation is blocked by a monoclonal CEACAM1 antibody. These data suggest that CEACAM1 is a major effector of VEGF in the early microvessel formation. Since CEACAM1 is expressed in tumor microvessels but not in large blood vessels, CEACAM1 may be a target for the inhibition of tumor angiogenesis.

Adenosine Triphosphatases↗
PubMed1996

Compound motor action potential recording distinguishes differential onset of motor block of the obturator nerve in response to etidocaine or bupivacaine.

The purpose of this investigation was to establish an objective (quantitative) method for determining onset time of motor block induced by different local anesthetics. Twenty-four consenting patients undergoing transurethral surgery during spinal anesthesia were randomized to receive direct obturator nerve block with 10 mL of plain bupivacaine 0.5% (n = 12) or 10 mL of plain etidocaine 1% (n = 12). Another 14 patients (control group) received obturator nerve "block" with saline. After identification of the obturator nerve, patients underwent testing of nerve conduction by recording compound motor action potentials (CMAPs) of thigh adductor muscles in response to stimulation provided by a nerve stimulator at 0.2 to 0.5-mA currents. Testing ended when CMAP amplitudes had returned to their baseline values (control group) or when motor blockade was 90% complete (local anesthetic groups). In all 38 patients, the amplitude of the thigh CMAPs decreased immediately after injection of saline or local anesthetic. While CMAP amplitudes in the control group returned to their initial (baseline) values after 3-6 min, the patients receiving etidocaine or bupivacaine achieved > or = 90% motor blockade after 6 and 13 min, respectively. In the present report, the time to > or = 90% block was significantly faster in patients given etidocaine compared with those given bupivacaine. We conclude that electromyographic recording of CMAPs can be used to compare the ability of different local anesthetics to induce motor block.

Adult↗
PubMed1996

[Analysis of angiotensin converting enzyme (ACE) polymorphism in patients with myocardial infarction in the Polish population].

Analysis is presented of polymorphism of gene specifying angiotensin converting enzyme in Polish population and its comparison with results obtained for control group. Insertion/deletion polymorphism was detected by polymerase chain reaction. Frequencies of I/D alleles in control group were similar to those reported in French population but different frequencies were observed in patients with myocardial infarction.

Base Sequence↗
PubMed1996

[Voluntary aids in psychiatry].

Lay helpers fill in in situations where the natural system of help-family and friends-can no longer cope or where professional help is also not able to offer adequate help. Since no representative studies on this group of people exist, we wanted to take stock of the current situation by conducting a questionnaire in Baden-Württemberg. We identified 891 lay helpers in psychiatric facilities, of which 330 (37%) took part in the survey. The results of the study point out that lay help is the domain of older women. Their main duties are to give support through conversation and leisure activities. Although many lay helpers have been active over a long period of time, most of them express a high level of satisfaction with their occupation. A higher level of satisfaction is shown among those lay helpers who receive a certain amount of professional support in their work.

Aged↗
PubMed1995

In vivo isoproterenol treatment leads to downregulation of the mRNA encoding the cAMP response element binding protein in the rat heart.

The expression of different myocardial regulatory proteins is altered in human heart failure, e.g., beta 1-adrenoceptors, G-proteins and others. Similar changes in rats after 4 days treatment with isoproterenol led to the hypothesis of the cAMP pathway involved in these changes. In different cell types cAMP-dependent transcriptional activation is mediated by the cAMP-response element binding protein (CREB) which was recently shown to be expressed and phosphorylated in the human heart. Here, by the reverse transcriptase-polymerase chain reaction two alternatively spliced isoforms of CREB mRNA were found to be expressed in rat ventricles. Both isoforms were down-regulated in the ventricles of rats treated in vivo with isoproterenol (2.4 mg/kg per day) for 4 days proposing a possible mechanism involved in expressional changes mentioned above.

Adrenergic beta-Agonists↗
PubMed1995

cAMP response element binding protein is expressed and phosphorylated in the human heart.

BACKGROUND: In end-stage failing human hearts and in rat hearts after prolonged in vivo beta-adrenergic treatment, several proteins involved in the cAMP-dependent signal transduction are altered on the protein, mRNA, or transcriptional level, eg, beta-adrenoceptors, G-proteins, or proteins of Ca2+ homeostasis. In many tissues, cAMP-dependent transcriptional regulation occurs through the cAMP response element binding protein (CREB) and related transcription factors binding as dimers to cAMP response elements (CREs) in the promoter regions of regulated genes. METHODS AND RESULTS: To investigate a possible role of CREB in the human heart, nuclear protein of explanted failing and nonfailing human hearts was used to test for CRE specific binding properties in gel mobility shift assays. CRE specific binding was found in competition studies, and CREB and its phosphorylated form were immunologically identified in supershift experiments. The alternatively spliced CREB isoforms CREB327 and CREB341 were found to be expressed on the mRNA level by the reverse transcriptase-polymerase chain reaction. CONCLUSIONS: We conclude that in the failing and nonfailing human heart, CREB is expressed on the protein and mRNA levels and that CREB is phosphorylated and able to bind to CREs, indicating a functional role of CREB in the human heart.

Animals↗
PubMed1995

Electromyographic comparison of obturator nerve block to three-in-one block.

Obturator nerve block during spinal, epidural, or general anesthesia without muscle relaxants has been recommended for transurethral surgery to prevent thigh adductor muscle contractions during operative electrocautery. We investigated the effectiveness of direct obturator and 3-in-1 nerve motor blocks in 44 patients undergoing transurethral surgery during spinal anesthesia with isobaric bupivacaine. Patients were randomly assigned to receive 3-in-1 block with 40 mL (n = 13) or 50 mL (n = 11) of 1.5% lidocaine plus epinephrine, or direct obturator nerve block with 10 mL of 2% lidocaine plus epinephrine (n = 20). After both direct obturator and 3-in-1 blocks, compound muscle action potential (CMAP) testing of the obturator nerve was performed at 1-10-s intervals for 10 min. In patients given direct obturator nerve block (n = 20), CMAP amplitude decreased by 88.8 +/- 21% (mean +/- SD) from baseline. In contrast, 3-in-1 block reduced the evoked CMAP amplitude by 7.4 +/- 19% (P < 0.05). Peak lidocaine plasma levels of 1.6 +/- 0.2 micrograms/mL (range 1.0-2.8 micrograms/mL) were reached 60-90 min after the block in those patients receiving 50 mL of local anesthetic. The 3-in-1 technique fails to predictably result in effective motor block of the obturator nerve and thus may not prevent inadvertent thigh adductor muscle contractions during transurethral surgery. A direct approach to the obturator nerve is significantly more effective in producing motor block, and even when given in larger than recommended dosages it results in subtoxic peak plasma lidocaine concentrations.

Action Potentials↗
PubMed1994

Prevalence of beta allele of the insulin gene in type II diabetes mellitus.

Fifty-two patients and 36 controls were compared in a search for insulin gene variants among type II diabetic patients with fasting hyperinsulinemia (above 90 microU/ml) and a fasting C-peptide to insulin molar ratio between 1.11 and 1.50. Alpha and beta alleles of the insulin gene were characterized by restriction analysis of polymerase chain reaction (PCR) products and direct sequencing. The more frequent occurrence of the alpha allele of the insulin gene within the control population as compared with a prevalence of the beta allele in the diabetic patients (P, 0.05) was observed. The beta allele, usually described as the rare allele, seems to be associated with the disease.

Adult↗
PubMed1991

[Aseptic cerebral sinus thrombosis. 5 cases and a review].

From 1988 to 1990, we observed five cases of aseptic dural sinus and cerebral venous thrombosis, all in non-smoking women (age 18 to 47 years) receiving low dose oral contraceptives. Treatment consisted of full anticoagulation over 2 to 6 months, over which time the neurologic symptoms disappeared almost completely. Extensive tests of the blood clotting system in 4 patients after 6 to 19 months revealed a reduction of free protein S in 2 patients with a history of contraceptive use over several years, and normal results in 2 patients in which the sinus thrombosis occurred within the first 6 weeks of use of the oral contraceptive. Whether the protein S deficiency was congenital or caused by the oral contraceptive cannot be decided retrospectively. Even modern oral contraceptives seem to lead to an increased incidence of sinus thrombosis. Initial symptoms of sinus thrombosis include headache and somnolence, followed either by focal neurologic deficits (often associated with focal seizures) or by signs of increased intracranial pressure. CT scans show venous infarcts or general brain edema and may specifically show the "empty triangle sign" and "delta sign". The CT scan may also be normal if focal neurologic deficits are absent. MRI is favoured as it can directly show the thrombosed sinus or veins. Differential diagnosis includes arterial stroke, brain tumor, encephalitis or "benign intracranial hypertension", which should only be diagnosed after sinus venous thrombosis has been appropriately ruled out. Recently, full anticoagulation has been recommended as therapy.

Adolescent↗
PubMed1985

Incorporation of antigen 125I IgG into particular cell compartments: binding by chromatin.

Incorporation of [125I]IgG into spleen cells was studied in vivo and in vitro. In vivo, the antigen after uptake into the cytoplasm migrated into cell nuclei, where it was bound to chromatin up to the saturation level. One day after immunization the constant level of [125I]IgG was 1.3 X 10(12) molecules per spleen (10(8) cells). The same number of [125I]IgG molecules were bound to chromatin in cell cultures. The uptake of [125I]IgG was competitively inhibited by non-labelled IgG. Binding of [125I]IgG molecules reextracted from cytoplasm and chromatin with specific anti-human IgG serum argues against the uptake of degraded [125I]IgG molecules. [125I]IgG was tightly bound to DNA. Approximately 50 per cent of [125I]IgG was present in the residual chromatin fraction (after removal of 0.35 M and 2 M NaCl-soluble fractions) and 40 per cent was complexed with DNA (after removal of histones and non-histones AP1, AP2, AP3 and AP4). Binding of [125I]IgG by isolated chromatin was inhibited by the cytoplasmic fraction but not by BSA. Binding of [125I]IgG by fractionated chromatin, (chromatins remaining after removal of 0.35M, and 2M NaCl-soluble fractions or histones + non-histones AP1 + AP2 + AP3 + AP4) occurred at a level similar to that observed with native chromatin. The results suggest that interaction of antigen with immunocompetent cells is not restricted to the cell surface but that antigen seems to be taken up into cytoplasm, migrates to the nuclei and is bound to chromatin, probably directly to DNA. The results are discussed in relation to the induction of the immune reaction.

Animals↗
PubMed1985

Non-histone chromatin protein fractions associated with 'active' chromatin in embryonic chicken liver.

Non-histone chromatin proteins synthesized during chicken embryonic liver development were labeled with [3H]tryptophan and [3H]methionine and characterized by electrophoresis. During embryonic development protein/DNA ratio in chromatin was low (1.30-1.62) but synthesis of non-histone protein was high. Especially one characteristic fraction K (MW 18 000), tightly bound with DNA was preferentially associated with DNAase II sensitive, active transcribed sequences. In 7-day old and adult chicken synthesis of all non-histone proteins was low, fraction K was absent or synthesized only in small amounts in association with non-active sequences, however protein/DNA ratio in chromatin was high (2.30-2.33).

Age Factors↗
PubMed1984

Distribution of intraperitoneally injected [125I] BSA in cytoplasm, nucleoplasm and chromatin of lymphocyte-like and macrophage-like rat spleen cells.

[125I] BSA injected intraperitoneally penetrated into the cytoplasm and nucleoplasm of rat spleen cells, being rapidly and very tightly bound with chromatin. Distribution in lymphocyte-like and macrophage-like cells was quite similar, but in lymphocyte--like cells between the 4th and 8th day [125I] BSA was totally degraded, while in macrophage-like cells it was still present, being degraded between the 8th and 14th day.

Animals↗