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Biomedical subjects

T Berger

Publications and source records attributed to T Berger.

At least 55 records · Page 3Linked to original sources

[HIV patients with psychiatric illnesses. Treatment strategies and drug interactions].

Since the beginning of the endemic phase of the human immunodeficiency virus (HIV), about 60,000 humans have been infected in Germany by this retrovirus. Epidemiological data indicate approximately 2,500 new infections annually. Due to the multiagent antiviral therapy available, only about 600 cases progressed to the clinical picture of full-blown acquired immunodeficiency syndrome (AIDS) in 1999. [Robert-Koch-Institut (Berlin), http://www.rki.de] If an HIV infection or AIDS is current, a higher prevalence of psychiatric disorders in these persons can be anticipated. Psychoactive drugs and their dosages need to be chosen under several considerations and with regard to the HIV infection, since interactions between antiviral and psychotropic drugs occur frequently. The use of psychotropic drugs is often required and thus cannot be ignored. Therefore, psychiatric disorders, medical treatment strategies, interactions between psychotropic and antiretroviral drugs, and biotransformation mechanisms are discussed with regard to an underlying HIV infection.

Anti-HIV Agents↗

A biosensor for detecting changes in cognitive processing based on nonlinear systems analysis.

A new type of biosensor, based on hippocampal slices cultured on multielectrode arrays, and using nonlinear systems analysis for the detection and classification of agents interfering with cognitive function is described. A new method for calculating first and second order kernel was applied for impulse input-spike output datasets and results are presented to show the reliability of the estimations of this parameter. We further decomposed second order kernels as a sum of nine exponentially decaying Laguerre base functions. The data indicate that the method also reliably estimates these nine parameters. Thus, the state of the system can now be described with a set of ten parameters (first order kernel plus nine coefficients of Laguerre base functions) that can be used for detection and classification purposes.

Animals↗

Immunoglobulin subclasses in patients with neutralizing and nonneutralizing antibodies against IFN-beta1b.

Treatment of multiple sclerosis (MS) with interferon-beta1b (IFN-beta1b) induces the production of antibodies in some patients. A proportion of these antibodies can reduce the biologic activity of IFN-beta, and they are, therefore, referred to as neutralizing antibodies (NAB). The remaining antibodies do not interfere with the biologic activity of IFN-beta and are referred to as nonneutralizing antibodies (NNAB) in this paper. Immunoglobulin (Ig) subtyping of these antibodies was carried out, and Ig subclass patterns in 20 patients with NAB were compared with those of NNAB in 39 patients. In patients with NAB, IgG2 and IgG4 were found to occur more frequently than in patients with NNAB (30% vs. 3%, p = 0.05, and 55% vs. 18%, p = 0.003, respectively) The NAB titer correlated strongly with the IgG4 titer (r = 0.53, p = 0.02). Median total IgG, IgG1, and IgG4 titers were significantly higher in NAB than in NNAB patients (respectively, 8000 vs. 3200, p = 0.01; 1600 vs. 400, p = 0.0004; 200 vs. 0, p = 0.004). It is concluded that the development of NAB is related to both the quantity and the quality of the antibodies against IFN-beta1b.

Adult↗

High I(h) channel density in the distal apical dendrite of layer V pyramidal cells increases bidirectional attenuation of EPSPs.

Despite the wealth of recent research on active signal propagation along the dendrites of layer V neocortical pyramidal neurons, there is still little known regarding the traffic of subthreshold synaptic signals. We present a study using three simultaneous whole cell recordings on the apical dendrites of these cells in acute rat brain slices to examine the spread and attenuation of spontaneous excitatory postsynaptic potentials (sEPSPs). Equal current injections at each of a pair of sites separated by approximately 500 microm on the apical dendrite resulted in equal voltage transients at the other site ("reciprocity"), thus disclosing linear behavior of the neuron. The mean apparent "length constants" of the apical dendrite were 273 and 446 microm for somatopetal and somatofugal sEPSPs, respectively. Trains of artificial EPSPs did not show temporal summation. Blockade of the hyperpolarization-activated cation current (I(h)) resulted in less attenuation by 17% for somatopetal and by 47% for somatofugal sEPSPs. A pronounced location-dependent temporal summation of EPSP trains was seen. The subcellular distribution and biophysical properties of I(h) were studied in cell-attached patches. Within less than approximately 400 microm of the soma, a low density of approximately 3 pA/microm(2) was found, which increased to approximately 40 pA/microm(2) in the apical distal dendrite. I(h) showed activation and deactivation kinetics with time constants faster than 40 ms and half-maximal activation at -95 mV. These findings suggest that integration of synaptic input to the apical tuft and the basal dendrites occurs spatially independently. This is due to a high I(h) channel density in the apical tuft that increases the electrotonic distance between these two compartments in comparison to a passive dendrite.

Animals↗

Clinical, radiological, immunological and pathological findings in inflammatory CNS demyelination--possible markers for an antibody-mediated process.

The present report describes immunopathological, radiologcal and serological characteristics of antibody-mediated demyelination in a multiple sclerosis (MS) case with the main findings: (1) immunoglobulin and complement deposits in areas of active demyelination accompanied by massive macrophage activation; (2) ring-enhancing lesions in T1-weighted MRI after gadolinium application; (3) high titers of serum anti-myelin antibodies; and (4) signs of macrophage activation in the serum. Plasmapheresis may be a successful treatment for the type of inflammatory demyelination shown in the present case.

Autoantibodies↗

Anti-MOG and anti-MBP antibody subclasses in multiple sclerosis.

In a subset of multiple sclerosis (MS) patients antibodies against myelin antigens seem to be important in the demyelinating process. In this study we investigated IgM, IgA and IgG serum antibodies against the myelin oligodendrocyte glycoprotein (MOG) and the myelin basic protein (MBP) in 261 MS patients. Seventy-two per cent had anti-MOG antibodies, 59% were anti-MBP seropositive. The dominating antibody was anti-MOG IgM. A significant relationship between IgA and a progressive disease course was found. The predominance of IgGI together with the significantly associated occurrence of IgG3 against MOG corresponds to the prevailing IgGI and IgG3 isotypes in other autoimmune diseases. Patients who actually suffered from a relapse were significant more often anti-MOG and anti-MBP IgG3 seropositive than those in remission. However, patients treated either with intravenous immunoglobulins or interferon-beta showed a significant reduction of anti-MOG IgG3 antibodies.

Adult↗

Measurement of the depth distribution of average LET and absorbed dose inside a water-filled phantom on board space station MIR.

The Atominstitute of the Austrian Universities developed the HTR-method for determination of absorbed dose and "averaged" linear energy transfer (LET) in mixed radiation fields. The method was applied with great success during several space missions (e.g. STS-60, STS-63, BION-10 and BION-11) and on space station MIR in the past 10 years. It utilises the changes of peak height ratios in LiF thermoluminescent glowcurves in dependence on the LET. Due to the small size of these dosemeters the HTR-method can be used also for measurements inside tissue equivalent phantoms. A water filled phantom with a diameter of 35 cm containing four channels where dosemeters can be exposed in different depths was developed by the Institute for Biomedical Problems. This opens the possibility to measure the depth distribution of the average LET and the dose equivalent simultaneously. During phase 1 dosemeters were exposed for 271 days (05.1997-02.1998) in 6 different depths inside the phantom, which was positioned in the commander cabin. In phase 2 dosemeters were exposed in 2 channels in 6 different depths for 102 days (05.1998-08.1998) in the board engineer cabin, following an exposure in different channels in 3 different depths for 199 days (08.1998- 02.1999) in the Modul KWANT 2.

Humans↗

A comparative study of the relative bioavailability of different interferon beta preparations.

BACKGROUND: Three different recombinant interferon beta (IFNbeta) preparations are currently available for the treatment of MS, two IFNbeta-1a products (Rebif and Avonex) and one IFNbeta-1b product (Betaferon). These products differ with respect to the recommended dose, the dosage regimen, and the injection route. This study compared the relative biologic activity of these three products in vitro and in vivo. METHODS: Blood samples were collected from 237 patients with MS (170 on IFNbeta therapy and 67 control subjects receiving no therapy). Samples with neutralizing antibodies were excluded. Levels of the antiviral protein MxA and soluble vascular cell adhesion molecule-1 (sVCAM) in the four groups were measured by ELISA. In the in vitro investigation, untreated blood was incubated for 24 hours with increasing concentrations of the three IFNs from a dose of 1 IU/mL to 1000 IU/mL, after which levels of MxA were measured. RESULTS: A difference between the groups was observed in vitro, with a significant change from baseline in MxA levels being observed at 10 IU for Betaferon compared with 100 IU for Rebif and Avonex. However, this might be due to the different methods used for the determination of IU by the manufacturers. At the single-dose level there were no significant differences between IFNbeta preparations. In vivo, there were significantly different levels of MxA in the four groups. In the Betaferon group, the median value for MxA was 2.29 ng/105 peripheral blood leukocytes (PBL), compared with 1.00 ng/105 PBL for Rebif, 0.57 ng/105 PBL for Avonex, and 0.14 ng/105 PBL for the control group. Some significant differences between the groups were also apparent with respect to levels of sVCAM, which were higher with Betaferon than with Rebif. CONCLUSION: IFNbeta-1b induces higher levels of the above markers of IFNbeta bioactivity than either of the two IFNbeta-1a preparations. Moreover, there is a less striking difference between the two IFNbeta-1a preparations in favor of subcutaneous IFNbeta-1a.

Adjuvants, Immunologic↗

A critical comparison of frequently used methods for the analysis of tumor necrosis factor-alpha expression by human immune cells.

A variety of methods have been developed for the measurement of tumor necrosis factor (TNF)-alpha synthesis by immune cells. Here we have compared the results of the most common used methods, including in vitro stimulation of whole blood or peripheral blood mononuclear cell (PBMC) cultures with phytohaemagglutinin (PHA) or lipopolysaccharide (LPS) and RT-PCR analysis of TNF-alpha transcription in unstimulated PBMC. When we used EDTA treated blood samples we observed a significant correlation between the PHA and LPS stimulated TNF-alpha responses in whole blood or PBMC cultures. In contrast, TNF-alpha concentrations obtained from PHA and LPS stimulated whole blood cultures from citrate-treated blood did not show a correlation. We also found that the PHA stimulated TNF-alpha response was significantly higher in PBMC than in whole blood cultures, whereas the highest LPS stimulated TNF-alpha response was observed in citrate-treated blood. Moreover, the TNF-alpha response in both, citrate and EDTA treated whole blood cultures was significantly higher after LPS than after PHA stimulation. In contrast, in PBMC cultures the PHA stimulated TNF-alpha response was significantly higher than the LPS stimulated response. The results of RT-PCR analysis revealed a significant correlation with the PHA stimulated TNF-alpha response, both in whole blood assays and in PBMC cultures. In addition our results demonstrate that these different methods can only be compared when the influence of external factors such as the immediate processing of blood samples or the use of an appropriate anticoagulant and stimulant is considered.

Biological Assay↗

Molecular and functional characterization of protein 4.1B, a novel member of the protein 4.1 family with high level, focal expression in brain.

Brain-enriched isoforms of skeletal proteins in the spectrin and ankyrin gene families have been described. Here we characterize protein 4.1B, a novel homolog of erythrocyte protein 4.1R that is encoded by a distinct gene. In situ hybridization revealed high level, focal expression of 4.1B mRNA in select neuronal populations within the mouse brain, including Purkinje cells of the cerebellum, pyramidal cells in hippocampal regions CA1-3, thalamic nuclei, and olfactory bulb. Expression was also detected in adrenal gland, kidney, testis, and heart. 4.1B protein exhibits high homology to the membrane binding, spectrin-actin binding, and C-terminal domains of 4.1R, including motifs for interaction with NuMA and FKBP13. cDNA characterization and Western blot analysis revealed multiple spliceoforms of protein 4.1B, with functionally relevant heterogeneity in the spectrin-actin and NuMA binding domains. Regulated alternative splicing events led to expression of unique 4. 1B isoforms in brain and muscle; only the latter possessed a functional spectrin-actin binding domain. By immunofluorescence, 4. 1B was localized specifically at the plasma membrane in regions of cell-cell contact. Together these results indicate that 4.1B transcription is selectively regulated among neuronal populations and that alternative splicing regulates expression of 4.1B isoforms possessing critical functional domains typical of other protein 4.1 family members.

Amino Acid Sequence↗

Decision support software to help primary care physicians triage skin cancer: a pilot study.

OBJECTIVE: To determine whether decision support software can help primary care physicians proficiently triage lesions suggestive of basal cell and squamous cell carcinoma. DESIGN/MEASURES: Physicians selected triage options for 15 digitized images of skin lesions, with and without use of the decision support software. PARTICIPANTS/SETTINGS: Twenty primary care physicians practicing in a health maintenance organization or a city health clinic. INTERVENTION: Decision support software designed to help physicians arrive at a triage recommendation consisted of a clinical information form, a decision tree, and support features (teaching points, example images, and diagrams). RESULTS: Without using the decision support software, physicians chose the wrong triage decision 36.7% of the time; using the decision support software, they chose the wrong response only 13.3% of the time. Not using the decision support software, they failed to correctly perform a biopsy on or refer patients with cancerous lesions 22.1% of the time; using the software, they failed to correctly perform a biopsy on or refer patients with cancerous lesions only 3.6% of the time. Physicians scored an average of 3 points (of a possible 15 points) higher when they used the software (signed rank, 101.0; P<.001). They scored an average of 1 point higher on the 7 cancerous lesions when they used the software (signed rank, 65.5; P<.001). CONCLUSIONS: Use of decision support software could improve primary care physicians' triage decisions for lesions suggestive of nonmelanoma skin cancer, and potentially reduce morbidity and health care costs. We are designing a larger study to evaluate the accuracy and utility of the software with patients seen in clinical practice.

Basal Cell Carcinoma↗

Cutaneous aspergillosis and acquired immunodeficiency syndrome.

BACKGROUND: Primary cutaneous aspergillosis is an uncommon finding in patients with acquired immunodeficiency syndrome (AIDS); only 13 cases have been reported in the literature. OBSERVATIONS: We describe 11 patients with primary cutaneous aspergillosis and AIDS. There does not seem to be an age, sex, race, or human immunodeficiency virus risk factor predisposition. This is a late manifestation of AIDS; patients typically have low CD4 counts (<0.050 x 10(9)/L [<50/microL]) and other AIDS-defining illnesses. The most frequent presentation is in patients with cytomegalovirus disease and neutropenia caused by ganciclovir therapy. Lesions developed at the site of occlusive dressings for an indwelling intravenous catheter site in 10 patients. Neutrophil counts may be normal at the time of diagnosis. A minor presentation is in the patient without neutropenia as a result of traumatic inoculation. Histological findings and/or culture results are required for diagnosis. Patients develop cutaneous lesions despite prophylactic therapy with fluconazole. Lesions can be treated with excision and lifelong therapy with itraconazole. CONCLUSION: Because of the potential morbidity and mortality of cutaneous aspergillosis, a high level of suspicion and prompt institution of therapy is required.

Acquired Immunodeficiency Syndrome↗

Identification of homologous binding proteins in porcine and bovine gametes.

The purpose of this study was to determine if sperm and oocyte proteins that mediate plasma membrane interaction during mammalian fertilization are conserved among porcine and bovine gametes. We examined homologous and heterologous sperm and zona-free oocyte interactions to determine the extent of cross-reactivity between the gametes of these two ungulate species. First, the numbers of ejaculated porcine and bovine sperm bound to the oocyte plasma membrane of intact porcine and bovine oocytes were determined in vitro. There was no significant difference between the number of porcine or bovine sperm that bound to porcine or bovine oocytes (P > 0.25). Second, individual porcine and bovine sperm plasma membrane proteins were identified by binding of homologous or heterologous oocyte plasma membrane to whole sperm plasma membrane on Western ligand blots. The relative amount of labeled oocyte plasma membrane bound to individual sperm plasma membrane proteins was analyzed by laser densitometry. Eight porcine sperm plasma membrane proteins and seven bovine sperm plasma membrane proteins were bound by both porcine and bovine oocyte plasma membrane. A significantly greater relative amount of porcine oocyte plasma membrane than bovine oocyte plasma membrane was bound to the 14- and 10-kD porcine sperm plasma membrane proteins (P < 0.001 and P < 0.01, respectively). A 27-kD bovine sperm plasma membrane protein bound proportionally more bovine oocyte plasma membrane probe than porcine oocyte plasma membrane probe (P < 0.04). These results are consistent with conservation of similar receptor ligand interactions at the gamete plasma membrane among porcine and bovine gametes.

Animals↗

Myelin oligodendrocyte glycoprotein-DNA vaccination induces antibody-mediated autoaggression in experimental autoimmune encephalomyelitis.

One strategy to reestablish self tolerance in autoimmune diseases is based on the use of DNA vaccination to induce ectopic expression of the target autoantigen. We assessed the potential of vaccination with a DNA construct encoding the myelin oligodendrocyte glycoprotein (MOG), an important candidate autoantigen in multiple sclerosis, to induce tolerance and protect against experimental autoimmune encephalomyelitis (EAE). Unexpectedly, mice vaccinated with MOG-DNA developed an exacerbated form of EAE when challenged with either MOG or an unrelated encephalitogen, myelin proteolipid protein. We demonstrate that this is due to the inability of DNA vaccination to tolerize the MOG-specific T cell response and to the concomitant induction of a cytopathic MOG-specific autoantibody response, which is pathogenic, enhancing demyelination, inflammation and disease severity. Our data suggest that tolerogenic strategies for autoimmune diseases based on DNA vaccination should be approached with caution, as the outcome is unpredictable.

Animals↗

Immunopathogenic and clinical relevance of antibodies against myelin oligodendrocyte glycoprotein (MOG) in Multiple Sclerosis.

Recent neuropathological findings identified four distinct immunopathogenic pathways of demyelination and tissue destruction in the most common inflammatory demyelinating central nervous system disorder, Multiple Sclerosis. One of this neuropathological subtypes is characterised by features of antibody-mediated demyelination. A role of anti-myelin antibodies in the disease evolution of multiple sclerosis has been suggested already for a long time, however, their pathogenetic and clinical relevance is not understood yet. This present article will discuss recently published and some preliminary data on the immunopathogenic role of antibodies against myelin oligodendrocyte glycoprotein (MOG) and other myelin/nonmyelin targets in multiple sclerosis, as well as possible clinical implications for prognosis and therapy in the future.

Animals↗

[Recurrent abdominal pain].

BACKGROUND: Recurrent abdominal pain is found in 10-25% of school-aged children, thus being one of the most frequent complaints in childhood. Despite that, our knowledge about this syndrome is still very incomplete. DIAGNOSIS AND THERAPY: In the majority of cases, the traditional diagnostic approach understanding abdominal pain as a symptom of an underlying organic or psychological disease does not lead to a well-defined diagnosis with straightforward therapy. The natural course of abdominal pain in childhood seems to be less favorable than often assumed. Modern biopsychosocial models of recurrent abdominal pain are presented as a basis for future multimodal therapeutic concepts.

English Abstract↗