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Biomedical subjects

J Bauer

Publications and source records attributed to J Bauer.

At least 307 records · Page 17Linked to original sources
PubMed1996

Seizure-inducing effects of antiepileptic drugs: a review.

Seizure-inducing effects can be observed in the treatment of epileptic patients with antiepileptic drugs (AED). This may be a paradoxical reaction (for example the increase of complex focal seizures due to carbamazepine, vigabatrin or phenytoin treatment) or a result of AED-induced encephalopathy (commonly induced by valproate in patients with complex focal seizures). A seizure increase during intoxication with AED is a rare phenomenon, thus, it is not directly related to this condition. An incorrect choice of drugs in the treatment of an epileptic syndrome or seizure type may provoke seizures (as for example the provocation of absences due to carbamazepine or phenytoin). The possible seizure-inducing effect of AEDs has to be differentiated from seizure occurrence due to the natural course of epilepsy. This may be especially difficult in patients suffering from West syndrome or Lennox-Gastaut syndrome, in whom seizure frequency may vary even without medication. However, especially in these patients, drug-induced worsening of seizure manifestation is often observed. In general, a seizure-inducing effect of antiepileptic drugs has to be considered when a seizure increase is observed soon after the initiation of therapy, when a stepwise increase of the dosage is followed by a further increase of seizures, a decrease of seizures is seen with tapering of the dosage and a renewed increase of seizures can be observed after this therapy has been reestablished. Finally, one knows that the clinical condition of encephalopathy due to valproate or carbamazepine is accompanied by seizure increase. In spite of these clinical aspects, the underlying mechanisms of seizure increase mostly remain unclear. From animal experiments it is obvious that especially carbamazepine and phenytoin may provoke generalized seizures as absences or myoclonic seizures. A seizure increase during vigabatrin therapy has been attributed to the increase of the cerebral amount of gamma-amino butyric acid, which is known to possibly exhibit inhibitory or excitatory neuronal effects. The occurrence of tonic seizures in patients with Lennox-Gastaut syndrome has been attributed to the sedative effect of the drugs; however, this conclusion is controversial. From a clinical point of view, one should consider young age of the patient, mental retardation, antiepileptic polytherapy, high frequency of seizures or prominent epileptic activity in the electroencephalogram previous to medication as risk factors for a possible seizure-inducing effect of antiepileptic drugs.

Animals↗
PubMed1996

A novel bone marrow frozen section assay for studying hematopoietic interactions in situ: the role of stromal bone marrow macrophages in erythroblast binding.

Bone marrow macrophages are found in intimate contact with erythroblasts. Exact mechanisms and functions of this interaction are unclear. New insights into erythroblast binding were obtained using a newly developed bone marrow frozen section assay. This modified Woodruff and Stamper assay has some important advantages compared to other adhesion assays. Erythroblasts specifically adhered to bone marrow macrophages forming clusters, as appear in vivo. Selective depletion of bone marrow macrophages by intravenous injection of dichloromethyl-enediphosphonate resulted in a release of immature erythroid cells to the peripheral blood. Furthermore no erythroblasts adhered to bone marrow sections without macrophages. Evaluating the binding of erythroblasts to bone marrow macrophages we found that this binding is temperature and cation dependent. The receptor for erythroblasts present on macrophages recognizes a sialyated protein as ligand on erythroblasts, since neuraminidase treatment of erythroblasts resulted in a decrease in binding. A possible candidate for the erythroblast receptor on macrophages is the ED2 antigen. ED2 is a differentiation antigen present on resident macrophages that has some biochemical features characteristic of an adhesion molecule. Erythroblast binding to bone marrow was inhibited using a monoclonal antibody directed against ED2.

Animals↗
PubMed1996

Tuberculoma presenting as an en plaque meningioma. Case report.

Intracranial tuberculomas generally present as either solitary or multiple lesions in the brain parenchyma. They are characterized by a ring-enhancing area on either computerized tomography scans or magnetic resonance images. A case is presented in which an intracranial tuberculoma was dural based and had an appearance similar to an en plaque meningioma.

Adult↗
PubMed1996

Burr hole neuroendoscopic fenestration of quadrigeminal cistern arachnoid cyst: technical case report.

Arachnoid cysts of the quadrigeminal cistern have been managed by cyst shunting and craniotomy with cyst fenestration. Two children are presented who underwent successful burr hole neuroendoscopic fenestration of symptomatic quadrigeminal plate cysts. The literature is reviewed with regard to the treatment of quadrigeminal arachnoid cysts, and the neuroendoscopic management of these cysts is described.

Adolescent↗
PubMed1996

[Resistance pattern of bovine Pasteurella].

The sensibility of 375 pasteurellae of bovine origin (215 pasteurella multocida--and 160 pasteurella haemolytica--strains) was examined against 16 antibiotics or chemotherapeutics by agar diffusion technique. A great part of the strains was resistant to oxacillin (41,18%), tylosin (79,14%), streptomycin (53,21%), sulfonamides (57,33%) and tetracycline (47,20%). Only a few resistant strains were found for cephalothin (5,07%), polymyxin B (0,27%) and enrofloxacin (0,53%). While 16,27% of all isolates were resistant to chloramphenicol, 100% of the pasteurella strains proved to be sensible to its structural analogon florfenicol. This is affirmed by the low minimal inhibitory concentrations (0,25-1,0 micrograms/ml) of this antibiotic.

Animals↗
PubMed1996

Immunomodulator OM 163-induced reversal of tumor-mediated immunosuppression and downregulation of TGF-beta 1 in vivo.

Although PROb colonic tumor cells are immunosuppressive, the immunomodulator OM 163 induced the disappearance of macroscopic peritoneal nodules in 50% of rats bearing a peritoneal carcinomatosis (p.c.) induced by PROb cells. When the p.c. developed, the number of T lymphocytes was low and the expression of interferon (IFN)-gamma mRNA in tumor nodules decreased very rapidly. The TGF-beta 1 secreted by PROb cells could be responsible for the immunosuppression, because the PROb cell supernatant inhibited IFN-gamma production and T lymphocyte proliferation. When the rats were treated with OM 163, an infiltration of T lymphocytes was observed in tumor nodules, as well as a high expression of the IFN-gamma mRNA. The antitumor efficiency of the immunomodulator OM 163 could be explained in part by a direct effect of OM 163 on T lymphocytes, because in vitro it stimulated the proliferation and the secretion of IFN-gamma of T lymphocytes. OM 163 could also act at the TGF-beta 1 level. Although OM 163 alone or in combination with IFN-gamma did not modify the TGF-beta 1 secretion by PROb cells in vitro, the expression of the TGF-beta 1 mRNA and the TGF-beta 1 protein content was decreased in vivo in treated tumor nodules.

Adjuvants, Immunologic↗
PubMed1996

[Retropectoral recurrence of breast carcinoma].

The authors submit a case-history which draws attention to the importance of sonographic examination for detection of relapses of breast cancer which cannot be detected by physical examination. They describe a 43-year-old woman four-and-a-half years after modified radical mastectomy on account of breast cancer with a relapse of a tumour, 7 mm in diameter, in a rectopectoral position while the musculus pectoralis major and minor and the thoracic wall were intact.

Adult↗
PubMed1996

[The detection of toxinogenic Bacillus cereus strains].

Investigations into optimal culture conditions for Bacillus cereus in order to detect bacterial toxins in a cell culture system showed that Dulbecco's modified Eagle's medium supplemented with 5% fetal calf serum is the medium best suited for this purpose. The highest toxicity levels were seen when bacteria were cultured at 21 degrees C. In 42 of 43 Bacillus cereus-strains isolated from milk and milk products, toxin formation was detected using the MTT-test. In 11 strains, toxin formation was even shown when bacteria were cultured at 4 degrees C. When culture supernatants were examined in a commercially available ELISA, all cytotoxic strains were shown to form diarrheal toxin.

Animals↗
PubMed1995

Stimulation of the sphingomyelin pathway induces interleukin-6 gene expression in human astrocytoma cells.

Interleukin-6 (IL-6) has previously been shown to participate in neurodegenerative processes including Alzheimer's disease. However, the mechanisms leading to increased IL-6 expression in the brain remain largely unknown. We have studied the effects of synthetic ceramides and sphingomyelinase as possible regulators of IL-6 gene expression in a human astrocytoma cell line. The synthetic ceramides C2- and C6-ceramide as well as the enzyme sphingomyelinase were able to induce IL-6 gene transcription and protein synthesis in a dose-dependent manner with maximal IL-6 mRNA levels being reached after 4 h of ceramide treatment. We propose that the sphingomyelin pathway is part of the signal transduction cascade leading to IL-6 gene expression in astrocytes, and that this pathway may be involved in IL-6-mediated neurodegenerative processes.

Astrocytes↗
PubMed1995

Induction of cytokine synthesis and fever suppresses REM sleep and improves mood in patients with major depression.

Beneficial effects of inflammatory events on certain psychiatric disorders, including depression, were reported sporadically by ancient Greek physicians, but have been described also in our times by a few psychiatrists during the past decades. During febrile inflammatory events, mediators of the immune system such as interleukin-1 can be detected in the brain and may act on their respective receptors which have also been demonstrated in the brain. Since cytokines such as interleukin-1 have been shown in animal studies to exert sedative behavioral effects, to be somnogenic, and to induce slow-wave sleep (SWS), we performed a pilot study to evaluate scientifically the anecdotically reported beneficial effects of inflammatory states on depressive disorders. Mood and sleep parameters were monitored in seven drug-free, severely depressed patients before, during, and after the administration of a single dose of endotoxin. All patients responded with a short pulse of increased synthesis of the cytokines tumor necrosis factor, interleukin-1, and interleukin-6 and elevated body temperature for several hours. During the night following endotoxin administration, rapid eye movement (REM) sleep was significantly suppressed, while changes in slow wave sleep were not significant. During the next day, all patients were in a significantly improved mood; however a rebound of REM sleep was observed in the second night after endotoxin administration and mood worsened again during the next days, indicating an only transient beneficial effect of the treatment.

Adult↗
PubMed1995

[Gynecologic oncology--present trends].

The incidence of all malignant tumours of the female reproductive organs in our country is on average by 40% higher than the worldwide incidence and with the exception of carcinoma of the uterine cervix it is still slowly rising. Gynaecological oncology emphasizes: prevention with accurate classification of premalignant changes to ensure adequate treatment; radical surgery primarily in invasive forms as well as with regard to staging as a prerequisite for indication of adjuvant treatment; interdisciplinary team cooperation which indicates without time losses all therapeutic steps, incl. inoperable tumours, and ensures permanent follow-up.

Female↗
PubMed1995

Appearance of inducible nitric oxide synthase in the rat central nervous system after rabies virus infection and during experimental allergic encephalomyelitis but not after peripheral administration of endotoxin.

The cellular localization of inducible (iNOS) and constitutive (cNOS) nitric oxide synthase was studied in rats by immunocytochemical techniques involving specific iNOS and cNOS directed antibodies and by NADPH-diaphorase histochemistry. Paraformaldehyde-fixed vibratome sections of brains and cryostat sections of peripheral lymph nodes were studied of rats treated with endotoxin (2.5 micrograms/kg or 2.5 mg/kg i.v.), rats infected with rabies virus, and rats exposed to experimental allergic encephalomyelitis (EAE). Endotoxin-treated animals showed no appearance of immunoreactive iNOS (ir-iNOS) cells in the brain with the exception of a few microglial cells near the median eminence and some meningeal macrophages. In the same animals however, iNOS-immunoreactive cells were found in peripheral lymph nodes. Neurons that stain positive for cNOS and for NADPH-diaphorase could be observed in brains of control as well as of endotoxin-treated animals with a similar distribution and staining intensity. In contrast, animals that had been infected with rabies virus or subjected to EAE, showed the appearance of ir-iNOS-positive cells in several brain areas. These cells are located near blood vessels and lesion sites. The majority of these cells are GSA-I-B4 isolectin-positive and therefore are likely to represent macrophages. Our data suggest that increased production of nitric oxide may play a role in the altered brain functions in rabies-infected and EAE rats. On the contrary, increased nitric oxide production is probably not involved in the non-specific symptoms of sickness induced by endotoxin.

Animals↗
PubMed1995

[Age dependence of interleukin 6 and acute phase proteins].

In 59 healthy subjects of different age groups with no signs of inflammatory processes, the basal II-6 levels were measured. The II-6 concentrations were significantly higher in the oldest group (66-90 years) than in the two other age groups (24-40, 41-65 years). A positive correlation was found between age and II-6 concentration (r = 0.470). Otherwise, a statistically detectable relationship was found merely with alpha-2-macroglobulin and with total and LDL cholesterol.

Acute-Phase Proteins↗
PubMed1995

A functional factor X deficiency.

A functional factor X deficiency is described which caused pronounced reduction in the in vitro activation of the extrinsic system while marginally affecting the in vitro activation of the intrinsic pathway. All studies were normal with the exception of a prolonged PT, an elevated factor X antigen, and low factor X activity. Western blot analysis revealed the presence of two factor X species. The abnormal molecule was of higher molecular weight. Interestingly, there was no bleeding associated with this deficiency. The biochemical basis of this defect is currently under investigation.

Adult↗
PubMed1995

Sodium chloride in separation medium enhances cell compatibility of free flow electrophoresis.

Free flow electrophoresis of cell suspensions in buffers containing sodium chloride was investigated using a modified procedure and the new apparatus Octopus PZE. The major methodical innovations are upward fluid flow, margin buffers flowing through the electrophoresis chamber at both sides of a central cell suspension buffer, adjacent to the electrode membranes, and a sample injection device which focuses the cells hydrodynamically to the middle of the chamber thickness. Mononuclear leukocytes, suspended in a buffer containing 35 mM NaCl, could be fractionated with the same accuracy as by conventional free flow electrophoresis, operated with a single NaCl-free chamber buffer. However, testing the vitality of separated cells with the help of the calcium indicator FURA2-AM clearly demonstrated the biological importance of the presence of a minimum amount of sodium chloride during cell electrophoresis. Only if at least 35 mM NaCl were present could an undisturbed cytosolic Ca2+ metabolism be maintained for the time of a free flow electrophoresis cell separation experiment.

B-Lymphocytes↗
PubMed1995

Resident microglia and hematogenous macrophages as phagocytes in adoptively transferred experimental autoimmune encephalomyelitis: an investigation using rat radiation bone marrow chimeras.

Hematogenous macrophages are known to be involved in the induction of tissue damage in the central nervous system (CNS) as well as of clinical symptoms in experimental autoimmune encephalomyelitis (EAE). Although resident microglia can become phagocytic under certain circumstances, little is known about the role of these cells in brain inflammation in vivo. We thus studied EAE in the model of radiation bone marrow chimeras that allows us to distinguish donor-derived hematogenous cells from resident effector cells. Inflammation in the CNS was qualitatively and quantitatively similar in chimeras compared to fully histocompatible Lewis rats. Although activated resident microglial cells were outnumbered four- to sevenfold in EAE lesions by hematogenous macrophages, the number of resident microglia with ingested myelin was equal to that of macrophages containing myelin debris. Phagocytic resident microglia, expressing the macrophage activation marker ED1, showed ramified as well as amoeboid morphology. From our studies the following conclusions can be drawn. First, a considerable proportion of resident microglia upregulated ED1. Second, resident microglia provide a small but substantial source of brain macrophages in EAE as compared to the large influx of macrophages. Third, our results suggest that microglia, due to their strategic position within the CNS, are more effective in removal of myelin debris compared to hematogenous macrophages.

Animals↗