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Biomedical subjects

M Gahr

Publications and source records attributed to M Gahr.

At least 91 records · Page 5Linked to original sources
PubMed1990

Localization of androgen receptors and estrogen receptors in the same cells of the songbird brain.

Estrogens and androgens each have unique effects but act together for the neural differentiation and control of sexual behaviors in male vertebrates, such as the canary. The neuronal basis for these synergistic effects is elusive because the spatial relation between estrogen target cells and androgen target cells is unknown. This study localized estrogen receptor (ER)-containing cells by using immunocytochemistry and androgen receptor (AR)-containing cells by using autoradiography in the same sections of the male canary brain. Three cell types, those containing only ER, those containing only AR, and those containing both ER and AR, were found in tissue-specific frequencies. The midbrain nucleus intercollicularis exhibited the highest number of cells expressing both ER and AR, whereas ER and AR are expressed only in disjunctive cell populations in the forebrain nucleus hyperstriatalis ventrale, pars caudale. Synergistic effects of androgens and estrogens for the neural behavorial control could result from cells containing both ER and AR (intracellular) and from neural circuits containing ER and AR in different cells (intercellular).

Animals↗
PubMed1990

Immunologic evaluation of children with homozygous beta-thalassemia treated with desferrioxamine.

In 15 children with thalassemia major (age 4-17 years) a detailed analysis of different immune functions was performed: phagocyte function, specific cellular immunity, humoral defense system. All patients had been subjected to a desferrioxamine therapy and a high transfusion regimen. Examination of neutrophil function included adherence, random migration, chemotaxis, killing of Escherichi coli and production of superoxide radical; these neutrophil functions were shown to be normal. In addition, lymphocyte proliferation in response to different lectins (phytohemagglutinin, concanavalin A, pokeweed mitogen) was identical in patients and controls. However, the number of circulating T-lymphocytes, helper T-cells and B-lymphocytes was increased in some patients. This phenomenon probably reflects an unspecific stimulation of the antibody-producing cells by repeated blood transfusions.

Adolescent↗
PubMed1990

Combination of congenital nonspherocytic haemolytic anaemia and impairment of granulocyte function in severe glucosephosphate isomerase deficiency. A new variant enzyme designated GPI Calden.

In two siblings, children of non-consanguineous parents, glucosephosphate isomerase (GPI) deficiency was found to be the cause of recurrent haemolytic crises. Characterization of the variant enzyme found in both individuals revealed low specific activity in erythrocytes and leucocytes, increased electrophoretic mobility and pronounced thermolability. Evaluation of the electrophoretic data allows the conclusions that these siblings are compound heterozygous carriers of GPI deficiency. The new variant was designated GPI Calden. Further investigations revealed that isolated granulocytes of both siblings show marked reduction of bactericidal activity and decreased production of superoxide anion. With rare exceptions, deficiency of this enzyme was supposed to cause congenital nonspherocytic haemolytic anaemia only. Here we report on two siblings presenting with the characteristic haemolytic anaemia and a significant decrease in granulocyte function, both presumably as the result of GPI deficiency. Our data indicate that impairment of granulocyte function might be a more general feature of severe GPI deficiency than formerly noted.

Anemia, Hemolytic, Congenital↗
PubMed1989

Distribution of estrogen receptors in the brain of the Japanese quail: an immunocytochemical study.

The distribution of estrogen receptors in the quail brain was investigated by immunocytochemistry using the monoclonal antibody H222SPy raised against estrogen receptors that had been isolated from a human mammary tumor. Nuclei which contained cells labeled for estrogen receptor were identified in the telencephalon, diencephalon and mesencephalon. In particular, a high percentage of labeled cells was observed in the lateral septum, the nucleus accumbens, the preoptic medial nucleus, the supraoptic nuclei, the anterior medial hypothalamus, the paraventricular magnocellular nucleus, the caudal parts of the lateral hypothalamus and in the whole tuberal and infundibular area. A small number of weakly labeled cells was also observed in the ventromedial nucleus of the hypothalamus. Although most of the positive cells were observed in the hypothalamic and preoptic area, a few areas were also labeled in other brain regions. This was particularly the case for the nucleus taeniae, the nucleus intercollicularis and the central gray. The distribution of labeled cells in this study closely matched with the distribution of cells which accumulated radioactivity following injection of tritiated estradiol in a previous study. The distribution of cells labeled by immunocytochemistry was similar in males and females and no evidence for a quantitative dimorphism in the percentage of labeled cells could be obtained. All nuclei containing cells labeled for estrogen receptors also contain significant levels of aromatase with the exception of the ICo.

Animals↗
PubMed1989

The gamma-chain heterogeneity of haemoglobin F in German infants.

gamma-chain heterogeneity of haemoglobin F was studied in German full-term and preterm infants up to 12 months old. The A gamma T-gene frequency calculated was about 19%. In most cases with A gamma I-/A gamma T-chain heterogeneity A gamma I-chains predominated over A gamma T-chains. There was no difference between infants with or without the A gamma T-chain concerning haemoglobin F-concentration, F-cell percentage or G gamma-chain percentage. The G gamma-chains accounted for 69.2% +/- 3.3% (SD) of the total gamma-chains in full-term newborn infants with a decrease to 42.5% +/- 6.5% during the first 6 months. Comparison of the G gamma-chain decrease in preterm and in full-term newborn infants suggests a more pronounced decrease during extrauterine life than during the intrauterine course.

Erythrocytes↗
PubMed1989

Predominant immunoglobulin gene rearrangements in two patients with immunodeficiency: restricted use of V gene segments and DNA hypermethylation.

The majority of common variable immunodeficiencies (CVID) is caused by intrinsic B cell defects which impede distinct stages of B cell differentiation. B cell differentiation is accompanied by the rearrangement of immunoglobulin (Ig) genes. The first step in the rearrangement process is the assembly of IgH genes, and subsequently, IgL genes are rearranged. During B cell maturation, Ig genes are demethylated in a stepwise, locus-specific manner. Here, we examined the Ig gene rearrangements of four patients with classical CVID and of one child suffering from an unusual immunodeficiency associated with CD5+ B cell lymphocytosis. In one of the four adult patients with CVID, we observed a predominant type of VHDJH-gene rearrangement. In the child, different polyclonal VHDJH-gene rearrangements were found together with a predominant type of kappa light chain gene rearrangement. The rearranged kappa chain genes were methylated (as in the pre-B cell stage). These findings together with the cell phenotype analysis and the clinical course of the disease in the child suggests that in some patients with primary immunodeficiency a maturation arrest may occur in B cells leading to a predominant Ig V gene rearrangement.

Adolescent↗
PubMed1989

[Unusual immunoglobulin gene rearrangements in patients with immunodeficiency].

In a 64-year-old patient with typical common variable immunodeficiency (CVID) DNA prepared from peripheral blood lymphocytes (PBL) showed a prominent immunoglobulin heavy chain (IgH) gene rearrangement; the immunoglobulin light chain (IgL) genes were found to be in the germline configuration. In contrast, a 13-year-old girl with a hitherto unidentified immunodeficiency showed polyclonal IgH gene rearrangements and a dominant IgL gene rearrangement. In both cases neither monoclonal B-lymphocytes nor monoclonal immunoglobulins were detectable. Our explanation for this unusual observation is that V-gene use in a given B-cell is not entirely random. This may be the consequence of a maturation arrest of B-cells.

Adolescent↗
PubMed1989

[Pathophysiology, diagnosis and therapy of disorders of granulocyte function].

Congenital disorders of polymorphonuclear leukocytes can be seen as a tool to learn more about the function of these cells. In this paper the pathophysiology of leukocyte adhesion deficiency and of chronic granulomatous disease is reported in detail, partly at the molecular level. Patients with leukocyte adhesion deficiency can be treated by bone marrow transplantation, whereas in chronic granulomatous disease the therapy is restricted to antibiotic treatment or surgical intervention. In some cases of chronic granulomatous disease an increase of polymorphonuclear leukocyte function by immunomodulators (gamma-interferon) may be a new therapeutic approach.

Cell Adhesion↗
PubMed1989

[The monocyte-macrophage system in the human].

The mononuclear-phagocyte system includes promonocytes and their precursors in the bone marrow, monocytes in circulation and macrophages in tissues. After maturation in the bone marrow newly formed monocytes enter the circulation and migrate into different tissues; the half-life of monocytes in the blood stream is approximately three days. Once in the tissue monocytes undergo transformation into tissue macrophages with functional properties that are characteristic for the environment in which they reside. Macrophages play a central role in the immune regulation by presenting antigen to T-lymphocytes; they participate in ingestion and killing of various invading microorganisms. In addition, macrophages synthesize a great number of substances involved in host defense and inflammation i.e. complement components, prostaglandins, IL-1, tumor necrosis factor-alpha and others. During infection, macrophages have the capacity to become "activated" by lymphokines and different bacterial products; "activated" macrophages have an increased tumoricidal and microbicidal activity against various microorganisms, synthesis and secretion of immune mediators is enhanced. Monocyte-macrophage dysfunctions have been described in various disorders: defective chemotaxis (corticosteroids, drug induced immunosuppression, AIDS, diabetes), defective phagocytosis (lupus erythematosus, deficiency of a membrane glycoprotein), microbicidal defect (chronic granulomatous disease), decreased cytotoxicity (Wiskott-Aldrich-Syndrome), deficiencies in the clearance of physiologic substrates in lysosomal diseases.

Child↗
PubMed1988

Developmental changes in estrogen-sensitive neurons in the forebrain of the zebra finch.

The brain areas for the control of song are sexually dimorphic in the zebra finch (Poephila guttata). Implantation of estrogen in young females within the first 40 days after hatching masculinizes their brain song areas. Monoclonal antibody (H222Sp gamma) against the estrogen receptor was used for the localization of estrogen-target cells in the brain. The nucleus hyperstriatum ventrale, pars caudale, was the only song control area that contained cells with estrogen-receptor sites. The number of these cells varied during ontogeny and declined sharply after day 40. No other song areas contained estrogen-target cells despite their ability to undergo masculine differentiation under the influence of estrogen. Therefore, the action of estrogen on these nuclei must be indirect.

Animals↗
PubMed1988

Phagocytosis-associated functions in neonatal monocyte-derived macrophages.

Using a Teflon culture system we analyzed different aspects of cell maturation and phagocytic activities in neonatal monocyte-derived macrophages. Morphological and cytochemical characteristics as well as the protein composition of neonatal macrophages were identical with those of adult controls; actin binding protein (265,000 Da), myosin (210,000), alpha-actinin (102,000) and actin (42,000) could be identified in cells from either source. All phagocytic functions were shown to be perfectly normal in neonatal macrophages when compared with adult cells: random migration, chemotactic response to zymosan-activated serum and formyl-methionyl-leucyl-phenylalanine, ingestion, and killing of Staphylococcus aureus, phagocytosis-associated chemiluminescence, production of oxygen intermediates (superoxide anion, O2-; hydrogen-peroxide, H2O2). Phorbol myristate acetate-stimulated O2(-)-generation by 1 x 10(5) macrophages was 11.8 +/- 4.7 nmol/h for neonates, and 10.2 +/- 3.9 for controls; production of H2O2 was 7.6 +/- 3.5 nmol/h in neonatal macrophages and 6.4 +/- 2.8 in adult controls. It is unlikely, then, that the increased susceptibility of human neonates to systemic bacterial infections can be related to an abnormality in the essential phagocyte functions of macrophages.

Cell Movement↗
PubMed1987

Immunocytochemical localization of estrogen-binding neurons in the songbird brain.

This study used monoclonal antibodies against estrogen receptor for the identification and localization of estrogen-binding cells in the avian brain. The distribution of estrogen-binding neurons in the songbird brain conformed to the general vertebrate pattern with highest labelling in hypothalamus and preoptic area. For the first time, estrogen-binding neurons were found in the song control system: these neurons might provide a substrate for the direct action of estrogen on the song system.

Animals↗
PubMed1987

The value of determination of homovanillic and vanillylmandelic acids in plasma for the diagnosis and follow-up of neuroblastoma in children.

The plasma levels of homovanillic and vanillylmandelic acids were determined in 84 children with neuroblastoma prior to treatment to evaluate the usefulness of these parameters for the diagnosis of this disease. Elevated levels of one or both of these metabolites were observed in 50% of children with Stage I or II disease, in 88% of those with Stage III, in 93% of those with Stage IV and in 100% of children with Stage IV-S for a total of 88% of all patients. The clinical course of the disease can be followed readily by determination of these metabolites, successful therapy or surgery being accompanied by a corresponding decrease in the plasma levels and relapse by a corresponding increase. Determination of homovanillic and vanillylmandelic acids in plasma can obviate many of the problems associated with the collection of urine, especially in young children or ambulant patients, and thus facilitates a more frequent control with consequent advantages for the management of this disease.

Child↗
PubMed1987

Elastase-alpha 1-proteinase inhibitor: an early indicator of septicemia and bacterial meningitis in children.

In 26 infants and children with septicemia or bacterial meningitis, significantly elevated plasma levels of elastase-alpha 1-proteinase inhibitor (E-alpha 1-PI) were present at time of recognition of infection, even in those patients with neutropenia (range of reference values: 25 to 190 micrograms/L, n = 142; patients: 444 to 2049 micrograms/L, n = 26). After initiation of therapy, normalization of E-alpha 1-PI levels was observed in all patients who recovered from infection. In addition, 18 of 19 children with bacterial meningitis had increased cerebrospinal fluid concentrations of E-alpha 1-PI above the range of normal (range of reference values: 0 to 39 micrograms/L, n = 62; patients: 30 to 3490 micrograms/L, n = 19); concentrations of E-alpha 1-PI in bacterial meningitis were significantly increased when compared with those in aseptic meningitis (range 25 to 194 micrograms/L; n = 15). In 30 patients with local bacterial infections (pneumonia, urinary tract infections, etc.), E-alpha 1-PI was also elevated. These data suggest that E-alpha 1-PI is a sensitive indicator of systemic and local bacterial infection in childhood.

Adolescent↗
PubMed1987

Diminished release of lactoferrin from polymorphonuclear leukocytes of human neonates.

In neonatal and adult polymorphonuclear leukocytes (PMN) we determined the content and the release of beta-glucuronidase, myeloperoxidase, lysozyme and lactoferrin. We found an equal total content of these proteins in adult and neonatal PMN, except for a lower lysozyme concentration in neonatal PMN. In the presence of opsonized zymosan myeloperoxidase, lysozyme and beta-glucuronidase were released in equal amounts; lactoferrin, however, was released to a lower rate from neonatal than from adult PMN (p less than 0.0005).

Adult↗
PubMed1987

[Hyper-IgE syndrome].

The Hyper-IgE-syndrome (Job-, Buckley-) is characterized by recurrent staphylococcal infections of the skin, the ears and the lungs, by an eczematoid dermatitis from early infancy on, and by extreme elevation of serum IgE. The inconstantly found decreased chemotaxis of the polymorphonuclear leukocytes seems to be a secondary sign of a so far unknown deficiency possibly of the T-cell mediated immunity. Thus, therapy is restricted to antibiotic and surgical treatment. Many patients have a typical coarse face and some involvement of the bones (osteoporosis, craniosynostosis).

Adolescent↗