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C Otto

Publications and source records attributed to C Otto.

At least 91 records · Page 5Linked to original sources
PubMed1999

Presynaptic localization of the PACAP-typeI-receptor in hippocampal and cerebellar mossy fibres.

The distribution of PACAP-typeI-receptor (PACAP-I-R) mRNA and protein was studied in mouse using probes and a newly developed antiserum recognizing all known splice variants. RNase protection assays revealed highest expression levels of PACAP-I-R mRNA in brain, in particular the hypothalamus and hippocampus. At the cellular level, in situ hybridization analysis demonstrated widespread distribution of PACAP-I-R mRNA in neurons throughout the brain, while glial cells did not express the gene. Highest expression levels of PACAP-I-R mRNA were observed in three regions: the limbic system, the hypothalamus, and the brainstem. In accordance with data obtained from in situ hybridization analysis, immunohistochemistry showed widespread distribution of PACAP-I-R like immunoreactivity in the neuropil. Rather strong immunoreactivity was found in cerebellar and hippocampal mossy fibres where double immunolabelling revealed the presynaptic localization of the receptor protein. At the ultrastructural level, PACAP-I-R like immunoreactivity was observed around synaptic vesicles and close to the presynaptic grid in hippocampal mossy fibre terminals. This finding is in contradiction to the described postsynaptic localization of the PACAP-I-R in dendritic processes of hippocampal granule cells in rat. Due to their presynaptic induction, mossy fibre LTPs are distinctly different from LTPs in all other hippocampal regions. Therefore, the presynaptic localization of the PACAP-I-R in mossy fibre terminals may implicate this gene in influencing the synaptic strength of the mossy fibre pathway and hence memory consolidation.

Animals↗
PubMed1999

The peptide transporter PepT2 is expressed in rat brain and mediates the accumulation of the fluorescent dipeptide derivative beta-Ala-Lys-Nepsilon-AMCA in astrocytes.

We describe the synthesis of a fluorescent dipeptide derivative, beta-Ala-Lys-Nepsilon-AMCA, which could be used as an excellent reporter molecule for studying the oligopeptide transport system in brain cell cultures. Fluorescence microscopic and immunocytochemical studies revealed that the reporter peptide specifically accumulated in astrocytes (type I and II) and O-2A progenitor cells but not in neurons or differentiated oligodendrocytes. In astroglia-rich cell culture the dipeptide derivative is taken up in unmetabolized form by an energy dependent, saturable process with apparent kinetic constants of KM = 28 microM and Vmax = 6 nmol x h(-1) x mg protein(-1) at pH 7.2. Competition studies revealed that the accumulation of beta-Ala-Lys-Nepsilon-AMCA is strongly inhibited by dipeptides and pseudopeptides such as bestatin, arphamenine A and B. The biochemical data indicated that the properties of this high-affinity oligopeptide carrier closely resemble those of the renal peptide transport system PepT2 and Northern blot analysis demonstrated that PepT2 mRNAis expressed in glial but not in neuronal cell cultures. In situ hybridization histochemistry also revealed a non-neuronal localization of PepT2 transcripts and a diffuse, widespread distribution of PepT2 signals throughout the entire rat brain. The selective accumulation of the fluorescent reporter molecule by brain cells under viable conditions may provide a useful tool for studying peptide uptake systems and other aspects of astroglial physiology.

Animals↗
PubMed1999

Noninvasive videomicroscopic monitoring of rat small-bowel rejection.

Successful small-bowel transplantation requires an early diagnosis of graft rejection. To date, little is known about macroscopic mucosal alterations during rejection. In the present study, these changes were analyzed in detail. Videomicroscopic monitoring of an enterostoma was performed after allogeneic heterotopic small-bowel transplantation in the rat (BN to LEW). Up to postoperative day (POD) 3 a mucosal edema was noticed (stage I of videomicroscopical alterations). The earliest changes related to rejection appeared on POD 6. The mucosa of the grafted intestine developed patchy paleness and interruptions in mucosal architecture. Crypts were slightly widened and their color turned to dark red (stage IIa). Progressively, these alterations spread over the mucosa on POD 7 (stage IIb). On POD 9, the mucosa appeared pale, villi were shortened, and crypts appeared wide and rounded. The mucosal surface was coated with fibrinous membranes (stage III). The videomicroscopic findings were closely related to the histological grading of rejection. We regard this technique of mucosal monitoring a simple and noninvasive method of detecting allograft rejection.

Animals↗
PubMed1999

Culture-specific views of child maltreatment and parenting styles in a Pacific-Island community.

OBJECTIVE: Providing culturally sensitive definitions of child abuse is difficult as perceptions of what constitutes abuse can vary around the world. This study was undertaken to assess how teachers in the Republic of Palau perceived the severity of potentially abusive incidents and what types of recommendations, if any, they would have for situations judged as severely abusive. Attitudes about child rearing practices were also evaluated. METHODS: Teachers (n = 141 ) were given: (1) a questionnaire consisting of 25 vignettes describing parent/child interactions that were potentially abusive and asked to rate the severity of abuse and recommended interventions for each vignette; and (2) a 40-item parenting styles questionnaires to evaluate attitudes about child-rearing practices. RESULTS: Teachers identified and recommended interventions for more severe forms of abuse at rates similar to other international samples. For less severe parental misconduct, teachers were reluctant to involve nonfamily and outside agencies. Sexual abuse was rated as the most serious type of abuse and when identified, intervention was highly recommended. Some traditional Palauan parenting practices that might be considered maltreatment by other cultures were not considered abusive. For parenting styles, older individuals were more likely to use guilt induction and less likely to use methods of acceptance. Aggressive parenting styles were negatively correlated with all forms of abuse, suggesting that teachers who used aggressive disciplinary styles were less likely to perceive abusive situations as harmful. CONCLUSIONS: These results indicate that cultural values and practices play important roles in shaping the definition and interpretation of child maltreatment.

Adult↗
PubMed1999

The prevention education program (PEP). A prospective study of the efficacy of family-oriented life style modification in the reduction of cardiovascular risk and disease: design and baseline data.

We describe design and baseline data of the Prevention Education Program (PEP), a home-based and family-oriented intervention program, aimed to assess and improve cardiovascular risk factors in school children and their families during an intervention period of 10 years. Started in 1994 in the German town of Nuremberg, currently 37 elementary schools (22 control and 15 intervention schools) are enrolled including 1740 families (1740 first graders, 3046 parents, and 1521 siblings). Major cardiovascular risk factors as well as dietary behavior are evaluated yearly using structured interview, physical examination, laboratory analysis, and seven-day-dietary protocols. The intervention package is applied to all families from intervention schools using regular home visits, health curricula and group sessions. Primary outcome is any reduction in cardiovascular risk factors by dietary intervention and health education compared to the control group getting only written information on the individual risk profile. The presented baseline data showing a high prevalence of cardiovascular risk factors in adults and in their children underline the need for such an intervention program in Germany.

Adolescent↗
PubMed1999

Characterization of the Asp94 and Glu242 mutants in myeloperoxidase, the residues linking the heme group via ester bonds.

The heme group of all mammalian peroxidases is covalently linked to the protein matrix via two esterbonds, as we have recently shown by Fourier transform infrared (FTIR) difference spectroscopy [Kooter, I. M., Pierik, A.J., Merkx, M., Averill, B.A., Moguilevsky, N., Bollen, A. & Wever, R. (1997) J. Am. Chem. Soc. 119, 11542-11543]. We have examined the effects of mutation of Asp94 and Glu242, responsible for those ester bonds in myeloperoxidase, on the spectroscopic properties and catalytic activity of this enzyme. Mutation of Asp94 in myeloperoxidase results in two species. The first species has spectroscopic characteristics similar to that of wild-type myeloperoxidase. The second species has spectroscopic characteristics similar to that of Met243-->Gln mutant, and it is therefore concluded that, besides loss of the ester bond involving Asp94, this species also has lost the sulfonium ion linkage that is also characteristic of myeloperoxidase. The Asp94-->Asn mutant still has about 30% residual peroxidase activity while for the Asp94-->Val mutant only a few percentage activity is left. When Glu242 is mutated the sulfonium ion linkage is not affected, but this residue together with its neighbouring residue Met243, according to resonance Raman spectra, is responsible for the low symmetry of the heme group. Mutation of either of these residues results in loss of the bowed distortion from the planar conformation, and in a heme group with higher symmetry. For the Glu242-->Gln mutant 8% residual peroxidase activity is found.

Aspartic Acid↗
PubMed1999

[Transplantation of porcine Langerhans islets for therapy of type I diabetes. The way to clinical application].

Transplantation of isolated pancreatic islets provides an interesting alternative to the present cure for diabetes: insulin injections and pumps. These are characterized by an insufficient glucose haemostasis and in the long run can induce kidney failure, blindness, heart failure, and amputations. Up to now more than 293 allogeneic islet transplantations have been performed in diabetics with chronical kidney failure. Despite some success, no real breakthrough has been yet achieved, though great efforts are being made to improve the various methodological steps on the way to clinical transplantation. The use of animal (xenogeneic) organs could be a solution to overcome the shortage of allogeneic donors. The current experimental and clinical research focuses on the use of pigs as organ donors, which have a number of advantages over the immunologically more compatible primates. This article reports on success and open questions concerning the efforts to isolate porcine islets for future clinical transplantation: the search for a suitable pig breed, the various isolation steps, purification and in vitro culture, transplantation models using-small and large animals, first clinical trials, and immunological reactions against the xenogeneic tissue. In addition, strategies to circumvent tissue rejection and future perspectives are discussed.

Alginates↗
PubMed1999

Functional characteristics of the telemedical network for the medical service of the Bundeswehr for support of operations outside Germany and civil-military co-operation.

The maxim governing the accomplishment of medical tasks by the Medical Service of the Bundeswehr stipulates that the soldiers will, in case of illness, accident or injury, receive medical treatment to the standard they can expect in the Federal Republic of Germany. In this context the introduction of telemedical applications into the Medical Service will improve the quality of the medical care through better and faster access for the medical officer assigned to a unit or a ship for requesting support to expert knowledge from military facilities or the civilian sector. The telemedical system is based on a high-class commercial PC. This workstation can be extended as needed with medical devices (x-ray film digitizer, dermatoscope, otoscope) and allows linkage to other imaging methods (e.g., videocamera, ultrasound). Currently this system is under evaluation in a multi centre trial. The participants of this telemedical network communicate via EURO ISDN lines with sufficient bandwidth. If terrestrial lines are not available the communication will be based on satellite capacity. The application of internet-technology additionally provides access to medical data bases respectively allows civil-military co-operation and the interoperability between medical services of allied armed forces. This future-orientated telemedical approach with its modular upwards-compatibility will provide, especially in its mobile version and by using communication standards, the possibility to support necessary civil-military co-operation in the area of disaster relief and missions outside of Germany in the future.

Germany↗
PubMed1998

Apoptosis of T lymphocytes in liver and/or small bowel allografts during tolerance induction.

BACKGROUND: Apoptosis of parenchymal cells has been described during allograft rejection. Immunologically privileged tissue in the mouse has been found to prevent rejection by initiating apoptosis of infiltrating lymphocytes. The aim of this study was to investigate whether apoptosis may play a role in T-cell regulation during rejection and subsequent tolerance induction after liver transplantation (LTx) and combined liver/small bowel transplantation (LSBTx). METHODS: LTx and LSBTx (Brown Norway-->Lewis) were performed without immunosuppression. Cell migration, activation, and apoptosis were investigated by means of sequential histology, immunohistochemistry, and the terminal deoxynucleotidyl transferase-mediated dUTP-digoxigenin nick end labeling assay. Donor (Brown Norway) and third-party (Dark Agouti) cardiac allografts were transplanted into LSBTx recipients to determine specific tolerance. RESULTS: Transient acute cellular rejection occurred after LTx and LSBTx and was followed by specific tolerance. The kinetics of apoptosis were similar in liver allografts after LTx and LSBTx, but differed from the processes in small bowel allografts after LSBTx. Apoptosis of parenchymal cells in the grafted livers correlated directly with interleukin-2 receptor expression of the infiltrating T cells. During the late phase of rejection, a peak of apoptosis in the lymphocyte infiltrate was demonstrated, characterized as predominantly apoptotic CD8+ T lymphocytes. CONCLUSIONS: These results demonstrate that specific tolerance is achieved in both LTx and LSBTx after a transient rejection crisis. Apoptosis is involved in graft rejection and tolerance induction. Activation of T lymphocytes correlates with parenchymal cell apoptosis in the allograft. T-cell inactivation seems to result in apoptosis of cytotoxic T cells and tolerance, which appears to be unique to the liver allograft.

Animals↗
PubMed1998

Chromatin structure in bands and interbands of polytene chromosomes imaged by atomic force microscopy.

Polytene chromosomes from Drosophila melanogaster, observed from squash preparations, and chromosomes from Chironomus thummi thummi, investigated under physiological conditions, are imaged using an Atomic Force Microscope. Various chromatin fiber structures can be observed with high detail in fixed chromosomes and correspond to structures which are also observed in chromosomes of diploid cells. Unfixed chromosomes can be imaged in buffer and show less fiber-like details because of the inherent soft nature of the chromatin material.

Animals↗
PubMed1998

Confocal Raman microspectroscopy of the activation of single neutrophilic granulocytes.

Confocal Raman micro-spectroscopy has been applied to investigate the activation process of single, living neutrophilic granulocytes. Both resting cells as well as activated cells were measured. The activation of cells was performed with phorbol-12-myristate-13-acetate activator and Escherichia Coli bacteria. Raman microspectroscopy combines a high spatial resolution inside a single, living cell with detailed material information. Using this approach it can be concluded that activation of the cells with phorbol-12-myristate-13-acetate causes a change in the redox state of cytochrome b558. This protein is a part of the NADPH-oxidase complex that neutrophilic granulocytes employ to generate O-2, superoxide anion. Additionally a change in the redox state of myeloperoxidase can be observed. Myeloperoxidase is known to react with O-2. Activation of the cells with bacteria gives rise to corresponding changes in the Raman spectra. From this single cell study it can be concluded that the enzymes cytochrome b558 and myeloperoxidase are present inside the cytoplasm of the living cell, while participating in the redox processes. Activation causes an intra-cellular release of oxygen metabolites. Activation with bacteria of neutrophilic granulocytes from a patient with chronic granulomatous disease, that contain no cytochrome b558, led to typical changes in the redox state of myeloperoxidase. This indicates that in the bacterium/neutrophilic granulocyte system oxygen metabolites are generated that are capable of reacting with MPO.

Granulomatous Disease, Chronic↗
PubMed1998

Resonance Raman microspectroscopy of myeloperoxidase and cytochrome b558 in human neutrophilic granulocytes.

With (resonance) Raman microscospectroscopy, it is possible to investigate the chemical constitution of a very small volume (0.5 fl) in a living cell. We have measured resonance Raman spectra in the cytoplasm of living normal, myeloperoxidase (MPO)-deficient, and cytochrome b558-deficient neutrophils and in isolated specific and azurophilic granule fractions, using an excitation wavelength of 413.1 nm. Similar experiments were performed after reduction of the redox centers by the addition of sodium dithionite. The specific and azurophilic granules in both redox states appeared to have clearly distinguishable Raman spectra when exciting at a wavelength of 413.1 nm. The azurophilic granules and the cytochrome b558-deficient neutrophils showed Raman spectra similar to that of the isolated MPO. The spectra of the specific granules and the MPO-deficient neutrophils corresponded very well to published cytochrome b558 spectra. The resonance Raman spectrum of the cytoplasmic region of normal neutrophilic granulocytes could be fitted with a combination of the spectra of the specific and azurophilic granules, which shows that the Raman signal of neutrophilic granulocytes mainly originates from MPO and cytochrome b558, at an excitation wavelength of 413.1 nm.

Cytochrome b Group↗