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B Trost

Publications and source records attributed to B Trost.

11 recordsLinked to original sources
PubMed2006

Peptidology: short amino acid modules in cell biology and immunology.

Short amino acid motifs, either linear sequences or discontinuous amino acid groupings, can interact with specific protein domains, so exerting a central role in cell adhesion, signal transduction, hormone activity, regulation of transcript expression, enzyme activity, and antigen-antibody interaction. Here, we analyze the literature for such critical short amino acid motifs to determine the minimal peptide length involved in biologically important interactions. We report the pentapeptide unit as a common minimal amino acid sequence critically involved in peptide-protein interaction and immune recognition. The present survey may have implications in defining the dimensional module for peptide-based therapeutical approaches such as the development of novel antibiotics, enzyme inhibitors/activators, mimetic agonists/antagonists of neuropeptides, thrombolitic agents, specific anti-viral agents, etc. In such a therapeutical context, it is of considerable interest that low molecular weight peptides can easily cross biological barriers, are less susceptible to protease attacks, and can be administered at high concentrations. In addition, small peptides are a rational target for strategies aimed at antigen-specific immunotherapeutical intervention. As an example, specific short peptide fragments might be used to elicit antibodies capable of reacting with the full-length proteins containing the peptide fragment's amino acid sequence, so abolishing the risk of cross-reactivity.

Amino Acid Motifs↗
PubMed2004

Evaluation of histogenesis of B-lymphocytes in pediatric EBV-related post-transplant lymphoproliferative disorders.

Post-transplant lymphoproliferative disorders (PTLD) are morphologically/clinically heterogeneous. The main goal of this study was to define the histogenesis of PTLD (B-cell phenotype, EBV-related) in seven pediatric patients after allogeneic T-cell-depleted bone marrow transplantation. Immunohistochemical stains using histogenetic markers, including Bcl-6 (expressed by germinal center (GC) B cells), MUM1/IFR4 (late GC and post GC B cells), and CD138 (post GC B cells), were performed on paraffin-embedded tissue. By morphology, four cases were classified as polymorphic PTLD and three as monomorphic PTLD, according to the WHO classification. By the expression pattern of histogenetic markers, five cases (two polymorphic, three monomorphic PTLD) were of late GC/early post GC B-cell origin expressing only MUM1/IRF4. The remaining two cases (one monomorphic, one polymorphic PTLD) were of post GC B-cell origin expressing MUM1/IRF4 and CD138, but not Bcl-6. Our study indicates that histogenesis of PTLD may be defined by histogenetic markers using immunohistochemistry. The results suggest that most pediatric PTLD are of late GC/early post GC B-cell origin, and a minor group is of post GC B-cell origin. The histogenesis of PTLD appears independent of morphologic appearance. Further studies are warranted to confirm our observation and to evaluate the clinical significance of histogenetic pattern of PTLD.

Adolescent↗
PubMed2001

Three-dimensional reconstruction of scleral cold thermoreceptors of the cat eye.

Sensory endings that respond to local cooling were identified electrophysiologically in the cat's sclera. Functionally identified scleral thermal fibers were then used to analyze the structural characteristics of cold receptor endings. Four Adelta units sensitive to controlled cooling of their scleral receptive fields were recorded. The receptive areas were mapped, demarcated with pins and examined electron microscopically using extensive three-dimensional reconstructions. The supporting tissue within the receptive areas of cold units consisted of dense collageneous tissue with a small number of blood vessels that were either veins or capillaries. Adelta nerve fibers were found within these tissue blocks presumably corresponding with cold sensitive fibers. Small nerves and single nerve fibers devoid of a perineurium were found in all parts of the tissue, only occasionally passing a blood vessel. The terminal portions showed axonal swellings all along the unmyelinated segment filled with mitochondria, glycogen particles, and some vesicles. About 30% of the terminal axonal membrane is not covered by Schwann cells. In the unmyelinated distal portion, the mitochondrial content ranged from 0.012 to 0.038 microm(3) mitochondrial volume per microm(2) nerve fiber membrane. In comparison with sensory endings in the cat's knee joint, cold receptors in the cat sclera showed many similarities in their three-dimensional structure with polymodal nociceptor endings of the knee joint but contain less mitochondria. This suggests that cold sensory endings do not require specialized cellular processes for the transduction of cold stimuli, as is the case for multimodal transduction and sensitization in the terminal portion of polymodal nociceptors.

Animals↗
PubMed1995

A new combination of methods for the localization, identification, and three-dimensional reconstruction of the sensory endings of articular afferents characterized by electrophysiology.

A combination of methods is described to identify and reconstruct corpuscular and non-corpuscular sensory endings of group II and group III nerve fibers following functional examination by electrophysiology. Afferent units activated by electrical stimulation of the medial articular nerve of the cat's knee were analyzed by single fiber recordings and characterized by their responsiveness to mechanical stimuli. The receptive fields of the units were closely demarcated by fine needles when the responses elicited by insertion of the needles were being recorded. After fixation, the tissue around the demarcated field was dissected and histologically processed. Series of semithin sections were cut from the embedded tissue blocks containing the receptive fields. Corpuscular endings of group II fibers and peripheral myelinated group III nerve fibers, presumably corresponding to the characterized units, were identified by light microscopy of semithin sections and localized within the demarcated area. Non-corpuscular endings were identified by electron microscopy of ultrathin sections cut in alternation with, or after re-embedding of, semithin sections. Morphometric analysis of ultrathin section series allowed the measurement of parameters such as the mean axon diameter and the organelle content of the sensory endings. The methods described are appropriate for collecting data that correlate the structural and functional characteristics of sensory endings in deep tissues.

Animals↗
PubMed1995

Effect of in vivo thyroid hormone status on insulin signalling and GLUT1 and GLUT4 glucose transport systems in rat adipocytes.

To examine the effect of thyroid hormone status on insulin action in isolated rat adipocytes, age- and weight-matched Sprague-Dawley rats were rendered hypothyroid (h) by i.p. injection of 2 mCi [131I]/kg. Another group of rats was made hyperthyroid (H) by i.p. injection of 500 micrograms L-thyroxine/kg/day for 7 days. The T4 levels in experimental groups were: controls, 33.5 +/- 0.95; h, 12.3 +/- 1.59; H, 133.2 +/- 8.8 micrograms/l. Adipocytes were isolated and 3-O-methylglucose transport (GT), insulin binding (IB) and insulin receptor kinase activity (IRKA) were determined. Subcellular membrane fractions (low-density microsomes, plasma membranes) were prepared and GLUT1 and GLUT4 glucose transporter immunodetected. Hyperthyroidism caused no significant effect on either IB or IRKA but increased insulin-stimulated GT by 43.6%. This increase of GT was associated with an increase of primarily GLUT4 glucose transporters. Hypothyroidism was associated with both increased insulin receptor affinity and enhanced IRKA. Despite a marked reduction of primarily GLUT4 glucose transporters, basal and insulin-stimulated GT was not reduced when compared with control. These results suggest that (1) in hyperthyroidism, increased insulin-stimulated glucose transport is associated with an increase of primarily GLUT4 glucose transporters, which may be responsible for the increment of peripheral glucose utilization in hyperthyroidism, and (2) the effect of hypothyroidism on insulin action in adipocytes is characterized by a state of increased insulin sensitivity, as indicated by the increase in insulin receptor affinity and tyrosine kinase activity. Despite the marked reduction of primarily GLUT4 glucose transporters, insulin-stimulated glucose transport is not diminished, which may suggest that functional activity of plasma membrane glucose transporters is enhanced in hypothyroidism.

Adipose Tissue↗
PubMed1993

Innervation of the dura mater encephali of cat and rat: ultrastructure and calcitonin gene-related peptide-like and substance P-like immunoreactivity.

Ultrastructural, immunocytochemical, and immunoelectron microscopical examinations are reported that describe the morphology of putative sensory nerve endings in the dura mater encephali of the rat and the cat. Morphometrical measurements and reconstructions showed that in the cat the mean diameter of axons, the bare area of axolemma, and the content of mitochondria and vesicles are highly variable in dural nerve endings. Nerve fibers with a high volume density of mitochondria are thought to be sensory, while nerve fibers containing many small vesicles are considered autonomic. There is, however, a broad overlap of mitochondria-rich and vesicle-rich nerve fibers in the dura, so that discrimination between sensory and autonomic endings by these characteristics frequently fails. Whole-mount preparations treated cytochemically for detection of substance P- and calcitonin gene-related peptide-like immunoreactivity in the rat and the cat showed a network of immunopositive nerve fibers in the vicinity of dural blood vessels. Most of these peptidergic and probably sensory nerve fibers were found terminating in the dural connective tissue far from vessels. Calcitonin gene-related peptide-positive nerve fibers were much more abundant than substance P-positive fibers. Immunoelectron microscopic preparations revealed that calcitonin gene-related peptide- and substance P-like immunoreactivity is found in a small proportion of generally thin unmyelinated nerve fibers. These proportions were very similar in the rat and the cat. Summarizing the recent literature, the morphological characteristics of putative sensory nerve fibers in the dura mater are discussed in relation to their possible functional significance for neurogenic inflammation and nociception.

Animals↗
PubMed1991

Autoimmune adrenalitis, asthma and membranoproliferative glomerulonephritis.

We report the first case of membranoproliferative glomerulonephritis in a patient with chronic adrenal insufficiency due to autoimmune adrenalitis. In addition, this patient developed extrinsic asthma. The pathogenic implications of autoimmune adrenalitis with a long lasting hypocortisolemic state and the appearance of immunologically mediated diseases are discussed.

Addison Disease↗
PubMed1978

[Transsexualism].

Explore the source record for details and available documents.

Diagnosis, Differential↗
PubMed1977

[Endocrinology of the chiasma syndromes (author's transl)].

A wealth of new knowledge about the function of the hypothalamo-hypophyseal system has been accumulated over the past ten years and progress keeps going at a fast pace. Several factors have contributed to this explosive growth: Pituitary hormones can now be measured by radio-immunoassay in body fluids, hypothalamic stimulating and inhibiting factors have been identified and are available for clinical studies and dynamic tests have been developed for detailed investigations of minor disturbances in the pituitary control system. A tremendous gain in accuracy of clinical diagnosis and endocrine follow-up is one of the consequences. Furthermore, new clinical pictures have emerged such as several variants of the hyperprolactinemia-hypogonadism syndrome or the concept of pituitary microadenoma. At the same time, neuropharmacology is also developing at a tremendous pace and exceedingly interesting perspectives linking neurotransmission with endocrinology and with various diseases of the brain are emerging. One highlight is the discovery of bromoergocryptine as a dopaminergic agonist, active in suppressing prolactin secretion as well as in treating Parkinsonism. In a second part of this presentation 5 cases with pituitary disease are presented. They were selected to cover part of the wide range of clinical signs and symptoms produced by tumours of the pituitary region. There is indeed no good relationship between ophthalmo-neurologic symptoms, destruction of the bony sella and endocrine disturbances.

Adenoma, Acidophil↗