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Biomedical subjects

D Herrmann

Publications and source records attributed to D Herrmann.

At least 37 records · Page 2Linked to original sources
PubMed2001

The neuropeptide head activator induces activation and translocation of the growth-factor-regulated Ca(2+)-permeable channel GRC.

The neuropeptide head activator stimulates cell proliferation of neuronal precursor and neuroendocrine cells. The mitogenic signaling cascade requires Ca(2+) influx for which, as we show in this paper, the growth-factor-regulated Ca(2+)-permeable cation channel, GRC, is responsible. GRC is a member of the transient receptor potential channel family. In uninduced cells only low amounts of GRC are present on the plasma membrane but, upon stimulation with head activator, GRC translocates from an intracellular compartment to the cell surface. Head activator functions as an inducer of GRC translocation in neuronal and neuroendocrine cells, which express GRC endogenously, and also in COS-7 cells after transfection with GRC. Head activator is no direct ligand for GRC, but its action requires the presence of a receptor coupled to a pertussis-toxin inhibitable G-protein. Heterologously expressed GRC becomes activated by head activator, which results in opening of the channel and Ca(2+) influx. SK&F 96365, an inhibitor specific for TRP-like channels, blocks Ca(2+) entry and, consequently, translocation of GRC is prevented. Head activator-induced GRC activation and translocation are also inhibited by wortmannin and KN-93, blockers of the phosphatidylinositol 3-kinase and of the Ca(2+)/calmodulin-dependent kinase, respectively, which implies a role for both kinases in head-activator signaling to GRC.

Androstadienes↗
PubMed2001

Fabrication of metal and polymer microstructures.

Microelectrical discharge machining (microEDM) is an innovative manufacturing technique for producing multifunctional metal microcomponents from difficult to machine materials such as nitinol and stainless steel. In addition, the microEDM technique allows the microstructurisation of stainless steel mould inserts for low-cost mass production of components made from various types of polymers.

Equipment Design↗
PubMed2001

Changes in the relative abundance of mRNA transcripts for insulin-like growth factor (IGF-I and IGF-II) ligands and their receptors (IGF-IR/IGF-IIR) in preimplantation bovine embryos derived from different in vitro systems.

The aim of this study was to determine the relative abundance of mRNAs for the insulin-like growth factor I (IGF-I) and IGF-II ligands, and for the IGF receptors (IGF-IR and IGF-IIR) in in vitro preimplantation bovine embryos from the oocyte to the hatched blastocyst stage using two different culture systems: TCM-199 supplemented with oestrous cow serum, or synthetic oviduct fluid supplemented with polyvinyl alcohol. Development to the two- to four-cell stage and blastocyst stage was significantly higher (P < or = 0.05) in embryos cultured in TCM supplemented with oestrous cow serum than in those cultured in synthetic oviduct fluid supplemented with polyvinyl alcohol (61 and 25% versus 55 and 17%, respectively). A semi-quantitative RT-PCR assay did not detect IGF-I transcripts at any stage of preimplantation bovine development, including the hatched blastocyst stage. In both culture systems, IGF-IR, IGF-II and IGF-IIR were expressed throughout preimplantation development up to the hatched blastocyst stage in a varying pattern. The expression patterns of IGF-IR, IGF-II and IGF-IIR in embryos generated in the two culture systems were not significantly different, except at the expanded blastocyst stage, at which significantly higher amounts of IGF-IIR were observed in the TCM system than in the synthetic oviduct fluid system. These results indicate that transcripts of IGF-IR and IGF-IIR follow the standard pattern in which maternal stores of mRNA in the oocyte are slowly depleted up to the 16-cell stage and then re-established at the onset of embryonic expression of these genes. The lack of detectable IGF-I transcripts in the bovine embryo indicates a predominantly paracrine mode of action. The bovine embryo is capable of producing IGF-II, IGF-IIR and IGF-IR in large amounts, particularly after hatching, which may be important for the formation of the filamentous conceptus. Results indicate an autocrine mechanism for IGF-II and modulation of IGF family expression by culture conditions.

Analysis of Variance↗
PubMed2000

Relative size of the literatures for psychopathological disorders: number of articles pertaining to DSM-IV diagnostic categories.

A computerized search of the 1991-1997 PsycLIT database was used to quantify the size of the literature for each of the DSM-IV mental disorders. The search included DSM-IV/IIIR diagnoses and alternative terms for the disorders to provide a complete assessment. Generally it was found that major disorders and those with neurophysiological components were investigated a great deal (there were over 10,000 articles for both major depression and schizophrenia) while there were few articles concerning rare or newly introduced disorders. Within diagnostic groups certain disorders received the preponderance of research attention. Factors related to the degree to which a mental disorder is investigated are discussed. These findings should stimulate consideration of whether clinical research is directing its efforts in a way that best promotes understanding of the nature and treatment of mental disorders.

Bibliometrics↗
PubMed2000

Surface membrane antigen alteration on blood basophils in patients with Hymenoptera venom allergy under immunotherapy.

BACKGROUND: Venom immunotherapy (VIT) provides widespread protection against systemic anaphylactic reactions after a sting of the respective insect. This effect is attributed to a shift from T(H)2 to T(H)1. However, because basophils also produce and release cytokines, such as IL-4 and IL-13, they may be part of the cytokine network. The cytokines may regulate basophilic granulocytes, as suggested by the presence of cytokine receptors IL-2Ralpha, GM-CSFRalpha, IL-1RII, IL-3R, IL-4R, IL-5R, and IL-6R on basophils from nonallergic donors. OBJECTIVE: The purpose of this study was to demonstrate that human basophils from subjects allergic to wasp venom undergoing VIT are regulated by cytokines, as shown by the alteration of the expression of cytokine receptors (and other markers). METHODS: The expression of the surface interleukin receptors and activation antigens on basophils from 19 nonallergic subjects and 48 patients with wasp venom allergy was investigated before, immediately after, and 1 week after VIT (20 patients only). RESULTS: Basophilic granulocytes in allergic subjects, compared with those in healthy persons, showed elevated expression of CD32 (FcgammaRII), CD122 (IL-2Rbeta), CD124 (IL-4Ralpha), CD130 (IL-6 and 11Rbeta), CD154 (CD40L), and HLA-DR. Activation of basophils clearly increased during VIT indicated by increased expression of CD32, CD33, CD35 (CR1), CD63, CD116 (GM-CSFRalpha), CD122, CD124, CD130, and CD154. HLA-DR expression also tended to increase. The expression of IL-5R (CD125) decreased. A significant decrease of the basophilic surface antigens CD11c, CD32, CD35, CD63, CD116, CD122, CD124, CD130, and CD132 (interleukin receptor gamma) was detected 1 week after the end of rush VIT. CONCLUSION: The rise in CD63 during VIT indicates a partial basophil degranulation with release of stored protein mediators, including IL-4. IL-4 may cause a transient upregulation of different surface antigens in an autocrine manner. Thereafter, cytokines released by T cells, which as a result of VIT have changed from a T(H)2 type to a more T(H)1 type, downregulate the activation of the basophilic granulocytes.

Adult↗
PubMed2000

Alternative splicing in the regulatory region of the human phosphatases CDC25A and CDC25C.

CDC25 phosphatases play key roles in cell proliferation by activating cell cycle-specific cyclin-dependent kinases (CDKs). We identified four new splice variants in the amino-terminal regulatory region of human cdc25C and one in cdc25A. All variants except one retain an intact catalytic domain. Alternative splicing results in loss of phosphorylation sites for kinases like CDK and the calcium/calmodulin-dependent kinase II (CaMKII), which influence CDC25 activity and compartmental localization. In NT2 teratocarcinoma cells, induced for nerve cell differentiation, the smaller sized variant of cdc25C was upregulated. At the protein level both phosphorylation state and isoform distribution differed between cell lines and cell cycle phases.

Alternative Splicing↗
PubMed2000

Effects of superovulated heifer diet type and quantity on relative mRNA abundances and pyruvate metabolism in recovered embryos.

This study investigated the effects of quantity and type of diet fed to superovulated donor heifers on molecular and metabolic indices of embryonic development. These effects included the relative abundances of mRNAs for the alpha 1 subunit of Na/K-ATPase and the antioxidant enzyme Cu/Zn-SOD, as well as pyruvate utilization in bovine morulae and blastocysts developed in vivo. Heifers were fed a daily ration of either grass silage and a citrus-beet pulp-based concentrate or grass silage and a barley-based concentrate for 116 days, both at 3 kg per day or ad libitum. In embryos derived from heifers fed the pulp-based diets, the relative abundances of the transcripts were not affected by either day of collection or quantity of diet. In embryos derived from heifers fed the barley-based diets, the relative abundances of the Na/K-ATPase transcripts were also not changed by these main effects, while the relative abundances of the Cu/Zn-SOD transcripts were affected by day of collection and by the quantity of diet. Pyruvate metabolism was affected by day of collection, and was significantly increased in day 8 embryos compared with day 7 and day 6 embryos. Diet quantity did not affect pyruvate utilization, whereas diet type did increase pyruvate metabolism in the barley group when compared with the pulp group. The results of this study show for the first time that molecular and metabolic variations may exist in embryos derived in vivo and developed in donor heifers on nutritional regimens differing in type and quantity. Differences in embryos collected on different developmental days may be attributed to varying cell numbers. Alterations in the relative abundances of the Cu/Zn-SOD transcripts and pyruvate metabolism caused by the quantity of diet fed to the donor animal were likely to have been due to alterations in metabolic end products that accumulate in reproductive tract fluids, whereas differences in embryonic metabolism caused by type of diet are related to the composition of the diet. These findings characterize embryos produced in vivo at the molecular level, indicating that the molecular markers used in the present study can differentiate between populations of embryos produced under different nutritional regimens and determine conditions conductive to the production of good quality embryos.

Analysis of Variance↗
PubMed1999

Alterations in the relative abundance of gene transcripts in preimplantation bovine embryos cultured in medium supplemented with either serum or PVA.

In preimplantation bovine embryos, the relative abundance of various developmentally important gene transcripts was determined by a semi-quantitative RT-PCR assay to analyze the effects of two medium supplements, serum or polyvinyl alcohol (PVA). Development to morula, blastocyst, and hatched blastocyst stages was higher (P < or = 0.05) in medium supplemented with serum than in medium supplemented with PVA. Connexin43 mRNA expression virtually disappeared from the 8-16 cell stage onward, but reappeared in the hatched blastocyst in serum-supplemented medium, whereas it was detected in PVA-derived embryos throughout development. No differences were found for plakophilin mRNA between both culture groups. Desmocollin II mRNA showed a sharp increase at the blastocyst stage in both groups with a higher transcription level in PVA-generated embryos. A significant difference in desmocollin III transcripts was detectable at the 8-16-cell stage between serum- and PVA-derived embryos. Transcripts for desmoglein 1 and desmocollin I were not detected at any preimplantation stage, irrespective of medium supplementation. The relative abundance of glucose-transporter-1 mRNA was significantly increased at the 8-16-cell stage in embryos produced in medium supplemented with PVA, but not serum. Heat shock protein and poly(A)polymerase mRNA were continuously expressed during preimplantation development in both culture groups. Although poly(A)polymerase mRNA was significantly elevated in PVA- over serum-derived embryos, heat shock protein mRNA expression was significantly enhanced in serum-generated embryos over PVA-derived embryos. Interferon tau mRNA showed a significant increase at the hatched blastocyst stage only in PVA-supplemented medium. These data suggest that alterations in mRNA expression are associated with culture environment. Timing and magnitude of the alterations varied among the different transcripts and were significantly affected by the presence of exogenous protein in a stage-specific manner, predominantly at critical developmental time points.

Animals↗
PubMed1999

Expression of human blood clotting factor VIII in the mammary gland of transgenic sheep.

By targeting the expression of sequences encoding non-milk proteins to the mammary gland of transgenic farm animals, the organ could serve as a 'bioreactor' for producing pharmacologically active proteins on a large scale. Here we report the generation of transgenic sheep bearing a fusion gene construct with the human blood clotting factor VIII (hFVIII) cDNA under the transcriptional control of a 2.2 kb fragment of the mammary gland specific promoter of the ovine beta-Lactoglobulin (beta-Lac) gene. Six founder animals were generated bearing a hFVIII cDNA construct with the introns of the murine metallothionein (MtI) gene (beta-Lac/hFVIII-MtI). Founders transmitted the transgene in a Mendelian fashion and two transgenic lines were generated. Ten out of 12 transgenic F1-females expressed rhFVIII mRNA in exfoliated mammary epithelial cells isolated from the milk. But only in transgenic F1 ewes 4010 and 603 hFVIII clotting activity estimated at 4-6 ng/ml was detected in defatted milk. Furthermore, the presence of rhFVIII-protein in ovine milk was demonstrated by a specific band at approximately 190 kD following immunoprecipitation and immunoblotting. Transgenic founder 395 expressed rhFVIII mRNA in biopsied mammary gland tissue, in exfoliated mammary cells as well as ectopically in brain, heart, spleen, kidney and salivary gland, suggesting that the employed beta-Lac promoter fragment lacks essential sequences for directing expression exclusively to the mammary gland. A rhFVIII standard preparation (rhFVIIIstd) was rapidly sequestered in a saturable fashion in ovine milk, thus rendering it largely inaccessible to immunoprecipitation although its biological activity was retained. Recovery of hFVIIIstd was dependent on milk donor, storage temperature and dilution of milk sample.

Animals↗
PubMed1999

A head-activator binding protein is present in hydra in a soluble and a membrane-anchored form.

The neuropeptide head activator plays an important role for proliferation and determination of stem cells in hydra. By affinity chromatography a 200 kDa head-activator binding protein, HAB, was isolated from the multiheaded mutant of Chlorohydra viridissima. Partial amino acid sequences were used to clone the HAB cDNA which coded for a receptor with a unique alignment of extracellular modules, a transmembrane domain, and a short carboxy-terminal cytoplasmic tail. A mammalian HAB homologue with identical alignment of these modules is expressed early in brain development. Specific antibodies revealed the presence of HAB in hydra as a transmembrane receptor, but also as secreted protein, both capable of binding head activator. Secretion of HAB during regeneration and expression in regions of high determination potential hint at a role for HAB in regulating the concentration and range of action of head activator.

Amino Acid Sequence↗
PubMed1998

The role of head injury in cognitive functioning, emotional adjustment and criminal behaviour.

In two investigations, 50% of non-violent convicted felons, who avoided incarceration by participating in a day reporting programme, reported a prior history of head injury and current problems in cognitive and emotional functioning. Only 5% of a college sample in the first investigation and 15% of a community sample in the second investigation reported prior head injury. In a third investigation, 83% of felons who had reported a history of head injury also reported a date for their head injury that preceded the date of their first encounter with law enforcement. Some participants reported no trouble with the law until after experiencing a head injury that occurred in their late thirties. Considering the research reported here and elsewhere in the literature, it appears that many serious crimes follow a head injury. One implication of the findings reported here is that many crimes might not occur if people with head injury were given prompt and comprehensive treatment after the injury.

Adaptation, Psychological↗
PubMed1998

"Don't know" responses in surveys: is what I know what you want to know and do I want you to know it?

Responses to survey questions are assumed to be based on what respondents can actually draw from memory. For example, if respondents report engaging in some behavior a certain number of times, we assume that a substantive answer reflects what they really know. Conversely, when respondents say that they "don't know" (DK) the answer, it is believed that their response reflects a lack of memory relevant to the question. However, survey responding is now understood to be a highly complex process. In this article, we propose a framework to account for the kind of reports made by respondents to a survey. The framework holds that respondent reports are based on three factors: what the respondent actually knows (the person's "cognitive state"); whether the respondent believes that the potential answer meets the requirements of the question (an "adequacy judgement"); and whether the respondent chooses to provide this answer (the person's "communicative intent"). Subsequently, the article examines how relevant findings in the literature support the framework, and then evaluates the assumptions made about cognitive states in light of the results of two experiments. The literature and research presented demonstrate that survey responding can be accounted for by a framework that assumes responding is based on certain key cognitive processes.

Adult↗
PubMed1998

Expression of RNA from developmentally important genes in preimplantation bovine embryos produced in TCM supplemented with BSA.

This study investigated the effects of a semi-defined culture system on the temporal pattern of expression of RNA from genes involved in compaction and cavitation: gap junction protein connexin43 (Cx43), desmosomal glycoproteins desmoglein 1 (Dg 1), desmocollins I, II and III (Dc I, Dc II, Dc III), desmosomal protein plakophilin (Plako); metabolism glucosetransporter-1 (Glut-1); RNA processing poly(A)polymerase (PolyA); heat shock protein 70.1 (HSP); and trophoblastic function trophoblast protein (TP) in bovine oocytes and embryos generated in vitro using TCM199 supplemented with BSA as the culture medium. Morulae and blastocysts derived in vivo were collected from superovulated heifers and also used for this study. Poly(A)+ RNA was extracted from pools of 20-50 oocytes or embryos, analysed by reverse transcription-polymerase chain reaction and the amplified fragments were verified by sequencing. Assays were repeated at least three times for each developmental stage and provided consistent results in all replicates. In bovine embryos produced in vitro, mRNA encoding Cx43 was detectable up to the morula stage, whereas blastocysts and hatched blastocysts did not express this gene. No transcripts were found for Dg 1 and Dc I throughout the tested preimplantation stages. Dc II and Dc III transcripts were found from 2-4-cell embryos up to the hatched blastocyst stage. mRNA encoding Plako was detected in immature and mature oocytes and zygotes, while no transcripts were seen in 2-4-cell and 8-16-cell embryos. The gene was expressed again from the morulae to the hatched blastocyst stage. Oocytes and bovine embryos produced in vitro showed transcripts for Glut-1, PolyA and HSP throughout preimplantation development up to the hatched blastocyst stage. The gene encoding TP was transcribed only in blastocysts and hatched blastocysts. Morulae and blastocysts produced in vivo showed the same expression as their in vitro counterparts, with one exception: the in vivo embryos transcribed Cx43. The results of this study reveal for the first time the transcriptional pattern of a set of 'marker' genes involved in various processes in early bovine embryonic development. Transferable morulae and blastocysts produced in vitro expressed most genes similar to their in vivo counterparts. These data contribute to the molecular characterization of this widely used in vitro culture system for bovine embryos and provide a major advance towards production of 'physiologically normal' embryos.

Animals↗
PubMed1998

Automated recording of RNA differential display patterns from pig granulosa cells.

We have developed a protocol for fast, nonradioactive, mRNA differential display reverse transcription PCR (DDRT-PCR) based on a commercial automated sequencer with RNA isolated from pig granulosa cells. We sought to discover conditions that would minimize the problem of using relatively small primers labeled with large infrared dye molecule, IR41, required for the sequencer. Extended IR41-labeled primers IR41-AAGC-T11-A, IE41-AAGC-T11-C and IR41-AAGC-T11-G gave more consistent differential display patterns than shorter anchored primers (IR41-T11A, IR41-T11C and IR41-T11G) without the additional (AAGC) cloning site. The optimal concentration of the extended labeled (downstream) primers was 20 pmol when 13-mer arbitrary (upstream) primers were used at a concentration of 4 pmol. Background smear and the intensity of amplified bands was significantly improved by changing from conventional Taq DNA polymerase to AmpliTaq Gold polymerase, which permits an improved "hot start" for the reaction. Running time (during which a digitized gel image is recorded) for a 26-cm polyacrylamide gel was 4 h, enabling us to analyze 90 reactions in an 8-h day. This protocol offers a rapid and reliable nonradioactive method for comparing gene expression patterns for various research or diagnostic purposes.

Animals↗
PubMed1997

Interleukin-6, soluble interleukin-2-receptor and soluble interleukin-6-receptor in sera of patients with rheumatoid arthritis: influences of disease activity and drug therapy.

Cytokines and their receptors play a fundamental role in the development and maintenance of the inflammatory process in rheumatoid arthritis (RA). The purpose of this study was to evaluate sIL-2R, sIL-6R and IL-6 levels in the sera of 48 RA patients and to correlate them with disease activity, indicators of inflammatory process as ESR and CRP, and drug treatment modalities. IL-6 and sIL-2R levels were positively correlated with disease activity, ESR and CRP. No correlation between sIL-6R levels and these markers were observed. Our results suggest that different drug therapies have a decisive influence on the levels of selected cytokines. All investigated disease-modifying antirheumatic drugs (DMARDs) were able to reduce the IL-6 level significantly. Non-immunosuppressive DMARDs decreased the amount of circulating sIL-2R more than immunosuppressive drugs. Treatment with methotrexate resulted in a significant reduction of circulating levels of sIL-6R compared to azathioprine therapy. Under low dose glucocorticoid therapy, significantly lower levels of sIL-6R were found than in patients without glucocorticoids. In conclusion, the results provide some arguments in favour of combined drug therapies, which might possibly enhance the effectiveness of RA therapy.

Adult↗
PubMed1997

Monitoring of serologic immune parameters in inflammatory skin diseases.

This paper deals with the correlation of clinical scoring and serologic markers of inflammation in atopic dermatitis and psoriasis. Serum eosinophil cationic protein (ECP), soluble interleukin-2 receptor (sIL-2R), total serum IgE, IgG and IgM anti-IgE antibodies, and IgE immune complexes were evaluated in monitoring inflammatory skin diseases such as atopic dermatitis and psoriasis. Well-established clinical activity scores were used as standards in recording skin improvement under treatment in a clinical setting. Serum ECP was found to be increased in both atopic dermatitis and psoriasis patients compared to normal controls; sIL-2R and IgE immune complexes were increased only in atopics with increased serum IgE. Anti-IgE antibodies did not show any deviation in both groups of patients. There was a significant elevation of sIL-2R and IgE immune complexes and a nonsignificant elevation of ECP in high-IgE atopics in comparison to those with normal serum IgE. In both groups of patients, there was a significant reduction of ECP and sIL-2R accompanying the improving skin condition. Serum IgE and the other immune parameters failed to respond. In contrast to other studies, serum ECP failed to correspond significantly with disease activity in our study. Our results showed measurable changes of ECP and sIL-2R for atopic dermatitis and/or psoriasis under treatment, but comparison to clinical scores remains difficult due to the different basis of the two systems. The only significant correlation was established for relative changes in sIL-2R and psoriasis area and intensity (PASI), a correlation which might be a useful approach in psoriasis.

Adolescent↗
PubMed1997

The proper use of self-report questions in effective measurement of health outcomes.

Outcomes research often relies on the use of general population survey data. The recent efforts to employ cognitive science theory in the development of data collection instruments has led to the establishment of new questionnaire design research methods. Intensive cognitive techniques are used in laboratory interviews to develop and pretest self-report survey questions with the goal of reducing non-sampling response error. This article presents the theoretical and applied approach used in the cognitive laboratory to study the ways people respond to surveys, and offers guidelines for improving self-report survey questions.

Cognition↗