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Biomedical subjects

R Paschke

Publications and source records attributed to R Paschke.

At least 145 records · Page 8Linked to original sources
PubMed1994

Association of sperm antibodies with other autoantibodies in infertile men.

PROBLEM: In many autoimmune diseases there is an increased incidence of other autoantibodies. However, the incidence of other autoantibodies in patients with seminal sperm antibodies is unknown. The most widely used tests to detect seminal and serum sperm antibodies are the mixed antiglobulin reaction (MAR) and the Tray agglutination test (TAT). METHOD: We therefore determined the incidence of antinuclear, antimitochondrial, thyroid peroxidase, and thyroglobulin antibodies, and rheumatoid factor in 147 patients investigated with MAR and 157 patients investigated with TAT. RESULTS: TAT positive patients had a significantly elevated incidence of antinuclear antibodies (chi 2 test, P < 0.005) and thyroglobulin antibodies (chi 2 test, P < 0.001). Thyroglobulin antibodies were increased in patients with MAR IgG > 40% and also significantly (chi 2 test, P < 0.05) increased in MAR IgA positive patients. Furthermore, thyroid peroxidase antibodies were only found in TAT positive patients. CONCLUSIONS: The consistently increased incidence of thyroid autoantibodies in infertile patients with sperm antibodies may indicate an increased risk for the development of autoimmune thyroid disease. This finding therefore suggests screening of patients with immunologic infertility for autoimmune thyroid disease and a further evaluation of the prognostic and pathophysiologic significance of thyroid autoantibodies in immunologic infertility.

Adult↗
PubMed1994

Presence of nonfunctional thyrotropin receptor variant transcripts in retroocular and other tissues.

The TSH receptor (TSHR) has been proposed as an antigenic link between the thyroid and the orbit; TSHR transcripts have been demonstrated by other groups, one in orbital tissue and the other in orbital and dermal fibroblasts. In a previous study we were unable to demonstrate transcripts for the complete TSHR in retroocular muscle containing also fibroblasts. We now confirm this finding. A 1.3-kilobase variant of the TSHR messenger ribonucleic acid (mRNA) has been described in normal and Graves' thyroids; it contains exons 1-8 of the major mRNA species and a unique 3'-sequence predicted to encode further amino acids and a polyadenylated tail. Lacking the membrane-spanning region, the corresponding variant protein, if expressed, is not expected to couple to G-proteins. Using primers specific for this variant in reverse polymerase chain reaction experiments, Southern blotting and frequencies, we demonstrate the presence of this transcript in normal and Graves' thyroid, extraocular muscle, peripheral blood mononuclear cells, and, to a lesser extent, in fat and fibroblasts. TSH-mediated protein synthesis, cAMP, and glycosaminoglycan production have been measured in cultured fibroblasts. At 5 mU/mL, bovine TSH stimulated glycosaminoglycan production, but recombinant TSH did not, even at higher concentrations, suggesting that contaminating factors are responsible. Together the data do not support the presence of a functional complete TSHR in orbital tissue. However, they are compatible with a role for the extracellular portion of the receptor as a nonfunctional autoantigen and provide some explanation for the conflicting results with regard to the relevance of the TSHR in the pathophysiology of thyroid-associated ophthalmopathy.

Actins↗
PubMed1994

Identification and functional characterization of two new somatic mutations causing constitutive activation of the thyrotropin receptor in hyperfunctioning autonomous adenomas of the thyroid.

It has recently been shown that somatic and germ line mutations of the TSH receptor gene cause autonomous hyperfunctioning thyroid adenomas and nonautoimmune toxic thyroid hyperplasia by constitutive activation of the TSH receptor. A "saturated" map of these mutations is a prerequisite for a systematic screening for these clinically important mutations. In this context, it is also of interest to determine whether different amino acid substitutions at the same residue cause constitutive activation of the TSH receptor, as suggested by site-directed mutagenesis of the alpha 1 beta-adrenergic receptor. We, therefore, screened further hyperfunctioning autonomous adenomas of the thyroid for constitutively activating mutations. We identified two new somatic mutations, changing alanine in position 623 to valine (A623V) and threonine in position 632 to isoleucine (T632I). Both mutations constitutively activated cAMP when transiently expressed in COS cells. Together with neighboring mutations, the T632I mutation demonstrates the importance of transmembrane domain VI for the activation of the TSH receptor and characterizes it as a hot spot for constitutively activating mutations. The previously identified A623I and the newly identified A623V mutations demonstrate that several amino acid substitutions at the same residue can cause constitutive activation of the TSH receptor.

Adenoma↗
PubMed1994

Importance of the extracellular domain of the human thyrotrophin receptor for activation of cyclic AMP production.

The mechanism by which the TSH receptor is activated is unknown. Current knowledge leads us to consider that G protein-coupled receptors are activated by positioning of their ligand in the pocket formed by the hydrophobic transmembrane segments. Furthermore, activation of an N-terminally truncated LH receptor lacking most of the extracellular domain has been described, suggesting the existence of a mechanism involving a direct interaction between LH and the transmembrane segments. The high conservation of the transmembrane segments among G protein-coupled receptors is a strong indication for a common mechanism of receptor activation. To test this hypothesis for the TSH receptor we have constructed four N-terminally truncated TSH receptor mutants with 5 or 69 amino acids of the extracellular domain joined to signal peptide regions consisting of the first 23 or 33 amino acids. The four fragments were amplified by PCR and subcloned into pBSK+. Sequences were confirmed after subcloning in M13. After joining the four fragments in pBSK+, the four TSH receptor constructs were subcloned in pSVL and transiently or stably expressed in COS and Chinese hamster ovary (CHO) cells respectively. In contrast to results obtained for the LH receptor, stimulation of the transfectants with 10 microM human chorionic gonadotrophin or 350 mU TSH/ml did not increase cyclic AMP (cAMP) concentrations in cultures of transiently transfected COS cells or stably transfected CHO cells. However, mRNA for the TSH receptor could be detected by RNase protection assay in all stable transfectants used for stimulation of cAMP.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1994

Intrathyroidal cytokine gene expression profiles in autoimmune thyroiditis.

Cytokines are thought to mediate the initiation and perpetuation of autoimmune thyroiditis. However, this concept is mainly based on in vitro findings and to date only interleukin (IL)-6 and interferon-gamma (IFN-gamma) have been detected in Graves' disease in vivo. The cytokine pattern produced by T-helper (Th) cells has important regulatory effects on the nature of the immune response. We therefore determined these cytokine mRNAs in Graves' disease and Hashimoto's thyroiditis. RNA was extracted by cesium chloride gradient centrifugation from the thyroid tissue of 12 patients undergoing thyroid resection for Graves' disease and from two patients being treated for Hashimoto's thyroiditis. Two patients with parathyroid adenomas and one patient with a goiter were used as controls. RNA was also extracted from normal human thyroid epithelial cells in primary culture. The cDNAs were prepared by reverse transcription and amplified for IL-2, -4, -5, -6 and -10 and IFN-gamma by polymerase chain reaction. All the cytokine mRNAs were detected in the Hashimoto's thyroid glands in large quantities. Six of the 12 Graves' disease thyroid glands showed, when compared with controls, an increased accumulation of transcripts for: IFN-gamma, IL-2, -4 and -10 or IL-2, -4 and IFN-gamma or IL-2 and IFN-gamma or IFN-gamma alone, each in one case or IL-2 alone in two cases. These cytokine profiles were not representative of a Th1 or Th2 phenotype. Increased amounts of cytokine mRNA in thyroid glands from Graves' disease patients were mostly associated with high microsomal antibody titres and/or prominent intrathyroidal lymphocytic infiltration.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

The influence of iodine on the intensity of the intrathyroidal autoimmune process in Graves' disease.

Several lines of evidence support an etiological role of iodine for the initiation and perpetuation of autoimmune thyroid disease. However, varying relapse rates after increased iodine supplementation have been reported for Graves' disease. Furthermore the effects of iodine on the intensity of human autoimmune thyroiditis have previously only been investigated by indirect parameters and actions of iodine on thyroid function and a possible enhancement of the intrathyroidal autoimmune process in Graves' disease are difficult to separate in previous studies. Moreover lymphocytic thyroiditis in animal models has always been induced by considerably higher iodine doses as those used in in vivo studies. Therefore we investigated the effect of low and high iodine concentrations on the intensity of the intrathyroidal autoimmune process in Graves' disease. The intensity of intrathyroidal infiltration by lymphocytes, memory T cells, plasma cells and antigen presenting cells was determined by quantitative immunohistologic methods in 38 Graves' disease patients. 12 patients received additional preoperative iodine (group II) and 26 were treated with thiourelene antithyroid drugs only (group I). Urinary and intrathyroidal iodine concentrations were determined by a modified cer arsenite method in both groups. Application of high iodine doses in group II induced a significant increase of kappa and lambda positive plasma cells and interdigitating reticulum cells. This was not observed for activated T cells. There was no correlation between the extent of intrathyroidal infiltration by activated T cells, plasma cells and antigen presenting cells, and intrathyroidal or urinary iodine or intrathyroidal iodine concentrations in group I.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Crystal structures of medium-chain acyl-CoA dehydrogenase from pig liver mitochondria with and without substrate.

The three-dimensional structure of medium-chain acyl-CoA dehydrogenase from pig mitochondria in the native form and that of a complex of the enzyme and a substrate (product) have been solved and refined by x-ray crystallographic methods at 2.4-A resolution to R factors of 0.172 and 0.173, respectively. The overall polypeptide folding and the quaternary structure of the tetramer are essentially unchanged upon binding of the ligand, octanoyl (octenoyl)-CoA. The ligand binds to the enzyme at the rectus (re) face of the FAD in the crevice between the two alpha-helix domains and the beta-sheet domain of the enzyme. The fatty acyl chain of the thioester substrate is buried inside of the polypeptide and the 3'-AMP moiety is close to the surface of the tetrameric enzyme molecule. The alkyl chain displaces the tightly bound water molecules found in the native enzyme and the carbonyl oxygen of the thioester interacts with the ribityl 2'-hydroxyl group of the FAD and the main-chain carbonyl oxygen of Glu-376. The C alpha--C beta of the fatty acyl moiety lies between the flavin and the gamma-carboxylate of Glu-376, supporting the role of Glu-376 as the base that abstracts the alpha proton in the alpha--beta dehydrogenation reaction catalyzed by the enzyme. Trp-166 and Met-165 are located at the sinister (si) side of the flavin ring at the surface of the enzyme, suggesting that they might be involved in the interactions with electron transferring flavoprotein. Lys-304, the prevalent mutation site found in patients with medium-chain acyl-CoA dehydrogenase deficiency, is located approximately 20 A away from the active site of the enzyme.

Acyl-CoA Dehydrogenase↗
PubMed1993

Mechanisms of hepatotoxicity caused by dacarbazine in rats.

Possible risks of fatal dacarbazine hepatotoxicity have not been studied systematically. We therefore asked whether dacarbazine hepatotoxicity is influenced by the dose or mode of application, by dacarbazine light-decay products, by prior liver damage or by an induction of dacarbazine metabolism. 22 Sprague-Dawley rats were treated with 4.5 mg and 200 mg dacarbazine/kg bodyweight i.p. and i.v., with dacarbazine light-decay products and with 4.5 mg and 200 mg dacarbazine/kg bodymass after previous galactosamine and ethanol treatment. Serum alanine aminotransferase, cholinesterase and white blood cell and platelet numbers were measured and liver histology was evaluated. Dose-dependent dacarbazine hepatotoxicity could be demonstrated by histology. The mode of application, dacarbazine light-decay products and acute liver damage did not influence dacarbazine hepatotoxicity. However 200 mg dacarbazine/kg bodymass after ethanol pretreatment caused significant serological changes and a significant leucodepression. The increased hepato- and myelotoxicity after induction of hepatic microsomal enzymes should be reason to exclude ethanol and drugs that induce hepatic microsomal enzymes prior to treatment with dacarbazine.

Alanine Transaminase↗
PubMed1993

Lack of evidence supporting the presence of mRNA for the thyrotropin receptor in extra-ocular muscle.

The search for autoantigenic targets in thyroid associated ophthalmopathy (TAO) and a possible link with the thyroid continues. Several authors have presented data suggesting that extrathyroidal tissues, e.g. extraocular muscle (EOM), may contain a functional thyrotropin receptor (TSH-R). We have applied Northern blotting and PCR amplification in an attempt to demonstrate the mRNA for the TSH-R in EOM, which although predominantly composed of muscle, may contain a significant proportion of fibroblasts. In Northern blots of poly(A) mRNA of normal human thyroid, EOM and skeletal muscle (SM) probed with a p32 labeled hTSH-R cDNA, transcripts of 4.6 and 4.4 kb were observed only in the thyroid. PCR amplification was performed on thyroid and EOM cDNAs using pairs of primers designed to amplify exons 1-->9, the extracellular domain (ECD), and exon 10, the intracellular domain (ICD). Both the ECD and ICD were amplified from a thyroidal cDNA library but only the ICD in the EOM cDNA library, this probably being due to the inevitable contamination with genomic DNA. These results do not support the hypothesis that the TSH receptor, as such, would be an autoantigen of EOM involved in TAO.

Adipose Tissue↗
PubMed1993

A search for circulating immunoglobulins blocking follicle-stimulating hormone action in male idiopathic infertility.

In this study, patients with idiopathic infertility were investigated for the presence of circulating antibodies which interfered with follicle-stimulating hormone (FSH) activity. A retrospective search for autoantibodies was undertaken using single plasma samples obtained from 29 infertile men with azoo/oligo/asthenoteratozoospermia and eight controls with normozoospermia and normal blood FSH levels. Plasma levels of immunoactive FSH, bioactive FSH, immunoactive luteinizing hormone and testosterone were measured in the individual samples. Plasma immunoglobulin G (IgG) was isolated using protein-A chromatography and tested at different dose levels for its ability to inhibit and/or stimulate basal and FSH-induced aromatase activity in immature rat Sertoli cells in vitro. In the first set of trials, IgGs isolated from three infertile patients showed apparent inhibition of FSH-stimulated aromatase activity, two showed further stimulation and five showed irregular fluctuations beyond the normal range of stimulation. When reanalysed at different doses, none of the IgG fractions exhibited abnormal interference with FSH action. It is concluded that, unlike many other endocrine disorders characterized by autoimmunity, the occurrence of autoantibodies of the IgG class blocking FSH action in male infertility is improbable.

Autoantibodies↗
PubMed1993

Lack of intrathyroidal tumor necrosis factor alpha in Graves' disease.

In vitro tumor necrosis factor alpha (TNF alpha) exerts a synergistic action on HLA class II expression and a cytotoxic action in FRTL-5 cells. Therefore, a role for TNF alpha as a local mediator of cell destruction in thyroid autoimmunity has been postulated. To elucidate the in vivo significance of these and other in vitro findings for the pathophysiology of Graves' disease we investigated 11 thyroid glands of patients suffering from Graves' disease for TNF alpha. In situ hybridization was done with a TNF alpha probe synthesized with T7 polymerase on a 750-base pair EcoRI fragment of the coding region. Primers at positions 152 and 854 in the TNF alpha copy DNA sequence were used for reverse polymerase chain reaction (PCR) amplification of TNF alpha in 5 patients. Immunohistological staining for TNF alpha was done with a mouse monoclonal antibody. We could not detect any TNF alpha and TNF alpha messenger RNA in thyroid tissue of 11 patients suffering mostly from relapsing Graves' disease by immunohistology and in situ hybridization as well as reverse PCR, respectively. A faint signal could be detected by reverse PCR in control thyroid tissue from a patient with recurrent goiter. This lack of intrathyroidal TNF alpha in relapsing Graves' disease is in accordance with a lack of increased TNF alpha production by T cell clones isolated from Graves' disease thyroid glands and contrasts with previous in vitro results. Since protective TNF actions have been demonstrated in other autoimmune diseases it could therefore be envisaged that the lack of intrathyroidal TNF alpha may be associated with the relapse of Graves' disease in our patients.

Actins↗
PubMed1993

Correlation of microsomal antibodies with the intensity of the intrathyroidal autoimmune process in Graves' disease.

Graves' disease is an organ-specific autoimmune disease, and intrathyroidal lymphocytes seem to be the major source of thyroid autoantibodies. Consequently, the intensity of the intrathyroidal lymphocytic infiltration is generally believed to reflect the activity of the autoimmune process. We, therefore, investigated the correlation of microsomal (enzyme immunoassay), thyroglobulin (RIA), and TSH receptor antibodies (RRA) with the degree of intrathyroidal infiltration by immunoglobulin G-producing plasma cells, activated T-cells, antigen-presenting cells, and the total number of lymphocytes. The immunocompetent cells were identified immunohistologically with monoclonal antibodies for immunoglobulins kappa and lambda, UCHL1, and the S100 antibody, respectively, in 26 thyroid glands of patients suffering from Graves' disease. The intensity of lymphocytic infiltration was determined by the point-counting method and by counting all lymphocytes and the labeled lymphocytes in 3 x 51 visual fields or 3 slides/thyroid gland. Microsomal antibodies correlated significantly (P = 0.001) with the total number of lymphocytes (r = 0.86), kappa (r = 0.71), lambda (r = 0.71), UCHL1 (r = 0.9), and S100 (r = 0.9) positive cells. These correlations were also significant for thyroglobulin antibodies. However, TSH receptor antibodies showed no significant correlations with any of the populations of immunocompetent cells. Patients with preoperatively undetectable TSH receptor or microsomal antibodies showed a broad variation of intrathyroidal infiltration by the immunocompetent cells investigated. Microsomal antibody titers, therefore, seem to reflect the intensity of the intrathyroidal autoimmune process in Graves' disease better than TSH receptor antibodies. However, the broad baseline variation in intrathyroidal infiltration observed with nondetectable thyroid antibodies will not always allow determination of the intensity of the intrathyroidal autoimmune process from microsomal or thyroglobulin antibody titers.

Adult↗
PubMed1992

Subclinical hyperthyroidism: physical and mental state of patients.

We investigated whether subclinical hyperthyroidism [subnormal basal thyroid-stimulating hormone (TSH) level, attenuated TSH response to thyrotropin-releasing hormone (TRH) stimulation, peripheral thyroid hormones within normal range] is accompanied by physical and mental changes. Thirty-five subclinically hyperthyroid patients (27 female, 8 male) were compared with 60 overtly hyperthyroid patients (51 female, 9 male) and with 28 euthyroid control patients (18 female, 10 male) with respect to physical symptoms, affective state, short-term memory, ability to concentrate and psychomotor performance. Patients with subclinical hyperthyroidism ranged between the other two groups. The major difference between controls and subclinically hyperthyroid patients was an increase in frequency of nervous symptoms and symptoms due to an increase of metabolic rate and thermal regulation changes. The major differences between subclinically hyperthyroid and overtly hyperthyroid patients were psychomotor impairment and symptoms of increased metabolic rate. Self-ratings of affective state tended to be similar in patients with subclinical and overt hyperthyroidism. The ability to concentrate and short-term memory were not impaired in any group. Symptoms in patients with subclinical hyperthyroidism probably result from central changes which lead to attenuated TSH responses to TRH, or from elevated but still normal thyroxine levels, which possibly enhance the effect of catecholamines.

Adult↗
PubMed1992

Relapse of Graves' disease following development of a pheochromocytoma.

Catecholamines stimulate thyroid hormone synthesis as well as release of thyroid hormone and cause immunologic disturbances that possibly contribute to the manifestations of Graves' disease. This has led to repeated speculations about the possible role of catecholamines in the initiation and maintenance of hyperthyroidism. We describe a patient with Graves' disease who was treated with antithyroid drugs for 2 years. After withdrawal of antithyroid drugs, the patient was in remission for 5 years. After the antithyroid drug treatment and the long remission, the probability of relapse of Graves' disease was very low. Nonetheless, a relapse did occur. Two years after subtotal thyroid resection, further investigation because of persistent hypertension revealed a pheochromocytoma. Retrospective anamnestic data suggest that this pheochromocytoma had been present 2 years before the patient's relapse of Graves' disease. This sequence of diseases has not been described previously. The low probability for a Graves' disease relapse in this patient and the association of this patient's relapse with the manifestation of a pheochromocytoma suggest a possible etiologic role of excess catecholamine production in the relapse of Graves' disease.

Adrenal Gland Neoplasms↗
PubMed1992

The possible etiological role of psychological disturbances in Graves' disease.

In the discussion of possible factors in the etiology of Graves' disease, stress has always played a major role. We investigated the possible influence of present depression (depressivity scale DS) and anxiety (State Trait Angstinventar STAI X1) on peripheral lymphocyte subpopulations in 10 patients with Graves' disease. The tests were done in hyperthyroidism and after 2-4 months in stable euthyroidism. Parallel to the psychometric testing, peripheral lymphocyte subpopulations were investigated. Elevated anxiety as a constant personality trait was investigated with the State Trait Angstinventar STAI X2 in 19 hyperthyroid patients with Graves' disease. 5 of the 10 patients had a pathological T4:T8 ratio and very high raw values for present anxiety (mean = 53,8; STAI X1), as well as a a high percentile for depression (median 93,1; DS). The other 5 patients with a normal T4:T8 ratio had much lower values for anxiety (mean = 37,8; STAI X1) and depression (median 78,4; DS). In those patients, the T4:T8 ratio remained normal in stable euthyroidism, while the values for anxiety and depression decreased. This also happened in the patients with a formerly pathologic T4:T8 ratio. However, the pathologic T4:T8 ratio persisted in those patients. The STAI X2 percentage ranking for the 19 hyperthyroid patients was 76,5. The value for healthy people is 55,5. Therefore a significantly elevated anxiety--representing a constantly elevated internal psychological stress--seems to be present in patients with Graves' disease. Since psychological stress is known to influence the immune system, such a constant personality trait could be a predisposing factor for Graves' disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Predominant intraepithelial localization of primed T cells and immunoglobulin-producing lymphocytes in Graves' disease.

It has been proposed that intrathyroid lymphocytes, localized in specific anatomical sites might have distinct, pathophysiologically relevant functions in Graves' disease. However, most studies of intrathyroidal lymphocytes were restricted to two lymphocyte locations and used semiquantitative methods. Therefore we used seven anatomically different lymphoid compartments to classify and evaluate by quantitative representative methods the total intrathyroidal lymphocytic infiltration and the staining indexes for immunoglobulin-producing plasmocytes and primed T cells (CD45RO), which provide maximum help to pokeweed mitogen-stimulated immunoglobulin synthesis in 36 thyroid glands from patients with Graves' disease. We found only 3.4% of all intrathyroidal lymphocytes intraepithelially. However, only intraepithelial lymphocytes showed a significantly higher staining index for primed T cells compared with several other compartments. There was also a high staining index for immunoglobulin-producing lymphocytes in this compartment. Kappa- and lambda-positive plasmocytes were found in a polyclonal distribution (kappa:lambda = 64.1: 35.9) in all compartments. This increased incidence of CD45RO-positive T lymphocytes and of immunoglobulin-producing lymphocytes among the intraepithelial lymphocytes suggests a distinct pathophysiological function of lymphocytes in peripolesis in Graves' disease. Furthermore, there is a polyclonal intrathyroidal immunoglobulin synthesis.

Adult↗