Biomedical subjects

W A Scherbaum

Publications and source records attributed to W A Scherbaum.

At least 73 records · Page 4Linked to original sources

PubMed2000

[Drug therapy of endocrine neoplasms. Part II: Malignant gastrinomas, insulinomas, glucagonomas, carcinoids and other tumors].

BACKGROUND: The thyroid gland and the adrenal glands are the most common sites of endocrine carcinomas (see Part I of this review, Med Klin 2000;95: 20-5, Nr. 1). Less frequent are endocrine malignancies of the gastrointestinal tract (gastrinomas, insulinomas, glucagonomas, carcinoids and others). TREATMENT: Because of the rarity and missing prospective studies as well as radiotherapy and chemotherapy resistance of these tumors, generally accepted conventional therapy guidelines for these endocrine carcinomas do not exist. Surgery and radionucleotide treatment should be considered as first line therapy. Somatostatin analogs (octreotide) are frequently used as well. Chemotherapy is usually not effective. Common substances are streptozotocin, 5-fluorouracil, doxorubicin, dacarbazine and cyclophosphamide.

Antineoplastic Agents↗

PubMed2000

[Drug therapy of endocrine neoplasms. Part I: Thyroid neoplasms, adrenal neoplasms and parathyroid neoplasms].

BACKGROUND: The incidence of endocrine carcinomas is about 5.3 persons per 100,000 population. Most frequent are malignancies of the thyroid gland (about 89%). THERAPY: Because of low incidences and missing prospective studies as well as radiotherapy and chemotherapy resistance, general accepted therapy guidelines for endocrine carcinomas are still missing. Surgery and radionucleotide treatment is generally the first-line therapy. Hormonal active carcinomas can be additionally treated with special substances such as octreotide and mitotane. Chemotherapy is frequently not effective. Widely used substances are cyclophosphamide, cisplatin, doxorubicine, dacarbazine, vincristine and etoposide. This first part of the review will present medical therapies of thyroid carcinomas, adrenal carcinomas and parathyroid carcinomas. The second part in one of the next issues will focus on less frequent endocrine carcinomas of the gastrointestinal tract.

Adrenal Gland Neoplasms↗

PubMed2000

Response of human monocyte-derived dendritic cells to immunostimulatory DNA.

Activated dendritic cells (DC) are of key importance for the initiation of primary immune responses and represent promising tools for immunotherapies in humans. Since DNA containing CpG motifs have been described as potent immunostimulatory (IS) adjuvants for murine DC, we here studied maturation and stimulation of functional activity in human monocyte-derived DC (MODC) in response to several immunostimulatory oligodeoxynucleotides (IS-ODN) and plasmid DNA (IS-PL). We show that exposure of MODC to IS-PL, but not IS-ODN, induced a dose-dependent strong up-regulation of HLA class II and co-stimulatory molecules (CD80, CD86), similar to that observed after treatment with TNF-alpha. Functional activity was assessed by the detection of increased secretions of IL-6 and IL-12(p75) following treatment with IS-PL. In addition, IS-PL-stimulated MODC acquired a high T cell-stimulatory capacity. T cells stimulated by tetanus toxoid-pulsed, IS-PL-matured MODC were significantly more frequently IFN-gamma positive (25.2+/-2.7%) as compared to TNF-alpha-treated MODC (15.4+/-1.4%), indicating a strong activation of Th1 lymphocytes. In conclusion, we demonstrate that human MODC are activated by IS-PL but not IS-ODN previously used as adjuvants in animal models. The Th1-like immune response observed after stimulation with IS-PL-treated DC suggests that preincubation of human MODC with IS-PL or coimmunization with IS-PL may represent an useful approach to generate strongly activated human MODC for several therapeutic applications such as DC-based tumor immunotherapy.

Adjuvants, Immunologic↗

PubMed2000

[Stiff-man syndrome from the perspective of internal medicine and immunology].

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Adjuvants, Immunologic↗

PubMed2000

Two amino acids in glutamic acid decarboxylase act in concert for maintenance of conformational determinants recognised by Type I diabetic autoantibodies.

AIMS/HYPOTHESIS: Glutamic acid decarboxylase 65 is a major autoantigen in Type I (insulin-dependent) diabetes mellitus, autoimmune polyendocrine syndrome and stiff-man syndrome. These disorders are characterised by the presence of multiple autoantibodies to the autoantigen which can be distinguished in a variety of different ways. We have investigated the role of single amino-acid mutations in glutamic acid decarboxylase 65 in distinguishing the binding of serum antibodies and a variety of patient-derived human IgG monoclonal antibodies directed to different determinants of the autoantigen. METHODS: We identified a mutant of glutamic acid decarboxylase 65 that contained four single amino-acid mutations from the wild-type molecule. The role of these mutations was investigated by site-directed mutagenesis. We investigated the binding of patient-derived serum antibodies to glutamic acid decarboxylase 65 to a number of single and double amino-acid mutants using immunoprecipitation with labelled, recombinant antigen. To overcome the heterogeneity of different anti-glutamic acid decarboxylase 65 antibodies present in a patient's serum, the binding of a panel of eleven patient-derived human monoclonal antibodies recognising different determinants on the autoantigen was also studied. RESULTS: Two replacements in glutamic acid decarboxylase 65 at Asn247Ser and Leu574Pro were identified that preferentially influence the anti-glutamic acid decarboxylase 65 serum antibodies of Type I diabetic patients, without statistically significantly effecting those recognised in other disorders. Single or double amino-acid replacements Asn247Ser and Leu574Pro in the autoantigen showed differential affects on expression of epitopes recognised by the human monoclonals. The double replacement of Asn247Ser and Leu574Pro in glutamic acid decarboxylase 65 resulted in the loss of binding of all eleven human monoclonal antibodies, irrespective of their epitope recognition. In contrast, single replacement of Leu574Pro statistically significantly reduced the binding of some carboxyl terminal-directed antibodies such as MICA 1, MICA 3 and DP-A without influencing the binding of other monoclonals. Replacement of Asn247Ser did not, however, influence the binding of any patients serum or human monoclonal antibodies. CONCLUSION/INTERPRETATION: Two distantly spaced amino acids, Asn247 and Leu574 in glutamic acid decarboxylase 65 were identified that act in concert to greatly influence the conformational structure of the autoantigen and statistically significantly influence the binding of antibodies present in Type I diabetic sera. The single or double amino-acid mutants can be used to distinguish some anti-glutamic acid decarboxylase-65 autoantibodies and could prove useful in distinguishing Type I diabetic from autoimmune polyendocrine syndrome and stiff-man syndrome patients' sera as well as to study changes in antibody patterns during disease progression.

Amino Acid Sequence↗

PubMed2000

Autoantibodies to ICA12 (SOX-13) are not specific for Type I diabetes.

AIMS/HYPOTHESIS: The majority of patients with Type I (insulin-dependent) diabetes mellitus has autoantibodies to insulin, glutamic acid decarboxylase and the tyrosine phosphatase-like protein IA-2. Some patients with Type I diabetes, in particular with adult onset diabetes, have, however, only cytoplasmic islet cell antibodies that could be directed to as yet unknown beta cell autoantigens. Recently, one potential antigen, ICA12, was identified as the high mobility group (HMG) box transcription factor SOX-13. Our aim was to evaluate the diagnostic sensitivity and specificity of autoantibodies to SOX-13 for autoimmune diabetes. METHODS: Full-length SOX-13 was cloned from human brain mRNA, expressed by vitro transcription/ translation and used to detect autoantibodies by immunoprecipitation and radioligand assay in patients suffering from autoimmune diabetes or non-organ-specific autoimmune diseases. RESULTS: We found SOX-13 antibodies to be present in 11 of 125 (8.8%) patients with newly diagnosed Type I diabetes and in 3 of 43 (7.0%) patients with latent autoimmune diabetes in adults. There was no association with age, sex and a particular pattern of diabetes-specific autoantibodies. Similar frequencies of SOX-13 antibodies were found in 84 patients with rheumatic diseases (4.0-11.4%) and 211 healthy control subjects (5.2 %). CONCLUSIONS/INTERPRETATION: Our data indicate that SOX-13 represents a minor target of autoantibodies in patients with autoimmune diabetes. Because SOX-13 antibodies were found not to be disease-specific, we assume they are not helpful in improving the diagnosis and prediction of Type I diabetes.

Adolescent↗

PubMed2000

Effects of a novel corticotropin-releasing-hormone receptor type I antagonist on human adrenal function.

Corticotropin-releasing hormone (CRH) is the principal regulator of the hypothalamic-pituitary-adrenal (HPA) axis and an activator of the sympathoadrenal (SA) and systemic sympathetic (SS) systems. Mental disorders, including major depression and, more recently, Alzheimer's disease have been associated with dysregulation of the HPA axis and the SA/SS systems. Treatment of rats or monkeys with the novel CRH receptor type 1 (CRH-R1) antagonist antalarmin inhibits the HPA and/or the SA/SS axes. This is the first study to examine the potential direct effect of antalarmin on human adrenal function. Adrenocortical and adrenomedullary cells were characterized by double-immunohistochemistry with anti-17 alpha hydroxylase (cortical cells) and anti-chromogranin A (chromaffin cells). Expression of CRH, ACTH, CRH type I and type II receptor mRNA were analyzed by reverse-transcription (RT) PCR. Human adrenal cortical and/or chromaffin cells in co-culture were incubated with CRH, antalarmin, and both CRH and antalarmin in vitro. Exposure of these cells to corticotropin or vehicle medium served as positive and negative controls, respectively. Cortical and chromaffin tissues were interwoven in the human adrenals, and both in situ and in the co-culture system the endocrine cell types were in close cellular contact. ACTH, CRH, and CRH-R1 and CRH-R2 mRNAs were expressed in the human adrenal as determined by RT-PCR. CRH (10-8 M) led to a moderate increase of cortisol release (145.7 +/- 20.0%) from cortical and chromaffin adrenal cells in co-culture. This effect corresponded to 41.8% of the maximal increase induced by ACTH (10-8 M). The action of CRH was completely inhibited by antalarmin. CRH, ACTH, and both CRH-R1 and CRH-R2 mRNAs are expressed in the adult human adrenal gland. CRH stimulates cortisol production in cortical and chromaffin cell co-cultures. This effect is blocked by antalarmin, a selective CRH-R1 receptor antagonist, suggesting that CRH-R1 receptors are involved in an intraadrenal CRH/ACTH control system in humans.

Adrenal Cortex↗

PubMed2000

Serum thrombomodulin-a reliable marker of disease activity in systemic lupus erythematosus (SLE): advantage over established serological parameters to indicate disease activity.

To date no specific serological parameter is available to assess disease activity in SLE. Soluble serum thrombomodulin is a new marker of endothelial cell injury and vasculitis. The objective of this study was to compare in vivo soluble thrombomodulin as marker of disease activity in SLE with established and recent serological parameters. One hundred and twenty-four sera of 30 patients with proven SLE with different disease activities were tested for serum levels of thrombomodulin, intercellular adhesion molecule-1 (ICAM-1), E-selectin, vascular cell adhesion molecule-1 (VCAM-1), IL-2R, IL-6, IL-10, dsDNA by ELISA and dsDNA additionally by radioimmunoassay (RIA). C-reactive protein (CRP), complement component C3, IgG, creatinine, anti-nuclear antibodies (ANA) and intermediate filament antibodies were measured by standard laboratory tests. The clinical disease activity was evaluated by the Systemic Lupus Activity Measure (SLAM). Correlations of the different serological SLE disease activity parameters with the SLAM scores revealed the highest significance for serum thrombomodulin (correlation coefficient 0.82). This was further confirmed by the intra-individual analysis of follow-up sera. In addition, a moderate correlation could be found for IL-6, IL-10, ICAM-1, CRP and erythrocyte sedimentation rate (ESR). In summary, soluble thrombomodulin is the most important serological parameter of disease activity in SLE currently available, as shown by the in vivo studies. Soluble thrombomodulin might be a valuable serological parameter for therapeutical considerations.

Adolescent↗

PubMed2000

Interaction of endothelial cells and neutrophils in vitro: kinetics of thrombomodulin, intercellular adhesion molecule-1 (ICAM-1), E-selectin, and vascular cell adhesion molecule-1 (VCAM-1): implications for the relevance as serological disease activity markers in vasculitides.

Recently markers of endothelial cell activation or injury gained increasing interest as serological parameters of disease activation in vasculitides. Among these, soluble serum thrombomodulin, ICAM-1, VCAM-1 and E-selectin are of particular interest. However, only thrombomodulin showed the expected close correlation. The objective of this study was to investigate in vitro the kinetics of these endothelial cell receptors after interaction of unstimulated or cytokine-activated polymorphonuclear neutrophils (PMN) and endothelial cells in order to find evidence explaining these different clinical findings. Over the time period of up to 48 h of incubation the kinetics of thrombomodulin, ICAM-1, E-selectin, and VCAM-1 levels in the supernatant of endothelial cells in co-culture with neutrophils were determined in vitro by ELISA under basal and partially cytokine-activated (tumour necrosis factor-alpha) conditions. Increased levels of ICAM-1, E-selectin and VCAM-1 were already found due to cytokine activation of endothelial cells alone. This increase was augmented after coincubation with neutrophils. In contrast, a significant increase of thrombomodulin in the supernatant was only found due to cell injury after cell-cell interaction of cytokine-activated endothelial cells with neutrophils. In conclusion, this in vitro model of the kinetics of soluble endothelial cell receptors after cell-cell interaction of cytokine-activated PMN and endothelial cells underlines the advantage of thrombomodulin in contrast to the adhesion molecules as a marker of endothelial damage. Therefore, soluble thrombomodulin seems to be a promising, valuable serological disease activity marker in vasculitides.

Autoimmune Diseases↗

PubMed2000

Mapping of novel autoreactive epitopes of the diabetes-associated autoantigen IA-2.

IA-2, a member of the tyrosine phosphatase family, has been identified as a dominant autoantigen in type 1 diabetes. To define humoral IA-2 epitopes, we generated a panel of IA-2 deletion mutants and chimeric proteins using the highly homologous tyrosine phosphatase-like protein IA-2beta. Analysis of autoantibody reactivity in 111 IA-2 antibody positive sera from patients with type 1 diabetes revealed that humoral epitopes cluster to several domains of the intracytoplasmic part of IA-2 [IA-2ic, amino acid (aa) 604-979]. Immunodominant epitopes were found in the first N-terminal 73 amino acids (56% positive), in the middle domain residing between residues 699-874 (45% positive) and the C-terminus depending on the presence of aa 931-979 (at least 37% positive). Competition experiments with overlapping peptides revealed that autoantibody binding towards the N-terminus was dependent on residues 621-628. In the C-terminal domain, two novel conformation-dependent epitopes were identified. The first epitope requires the presence of the C-terminal part of IA-2 (aa 933-979) and an IA-2-specific region between residues 771-932. Reactivity against the second epitope was dependent on intact C-terminal domains as well as residues in the middle (aa 887-932) and N-terminal regions (aa 604-771) which are conserved in IA-2 and IA-2beta. We here defined novel autoantigenic determinants in the N-terminus of IA-2 and characterized conformational epitopes residing in the C-terminal region or spanning from C-terminal residues to the N-terminal domain of IA-2ic. The identification of dominant target regions of diabetes-specific autoantibodies may help to elucidate the molecular mechanisms involved in the autoimmunity towards IA-2.

Amino Acid Sequence↗

PubMed2000

Comparison of octreotide acetate LAR and lanreotide SR in patients with acromegaly.

BACKGROUND AND OBJECTIVE: The most effective option for the medical treatment of patients with acromegaly is the use of somatostatin analogues. Long-acting depot formulations for intramuscular injection of two somatostatin analogues have recently become available: octreotide acetate LAR (Sandostatin LAR, Novartis Pharma AG) and lanreotide SR (Somatuline, Ipsen Biotech). We wished to compare efficacy of octreotide LAR and lanreotide SR in acromegalic patients. PATIENTS AND METHODS: A group of 125 patients with acromegaly (67 females; mean age, 47 years; 59 patients had previous pituitary irradiation) from 26 medical centres in France, Spain and Germany were studied. Before the study, all patients had been treated with intramuscular injections of lanreotide SR (mean duration, 26 months) at a dose of 30 mg which was injected every 10 days in 64 and every 14 days in 61 patients, respectively. All patients were switched from lanreotide SR to intramuscular injections of 20 mg of octreotide LAR once monthly for three months. In order to obtain efficacy and safety data of lanreotide SR under study conditions, it was decided to randomly assign at day 1, in a 3 : 1 ratio, the time point of the treatment switch; 27 of the patients were randomly assigned to continue the lanreotide SR treatment for the first 3 months of the study (group A); they were on octreotide LAR 20 mg from month 4-6. The other 98 patients were assigned to be switched to treatment with octreotide LAR 20 mg at day 1 (group B). In group B patients, octreotide LAR treatment was continued until month 6, with an adjustment of the dose based on GH levels obtained at month 3. RESULTS: The mean GH concentration decreased from 9.6 +/- 1.3 mU/l at the last evaluation on lanreotide SR to 6.8 +/- 1.0 mU/l after three injections of octreotide LAR (P < 0.001). The percentages of patients with mean GH values < or = 6.5 mU/l (2.5 microg/l) and < or = 2.6 mU/l (1.0 microg/l) at the last evaluation on lanreotide SR were 54% and 14%, and these values increased after 3 months treatment with octreotide LAR to 68% and 35% (P < 0.001), respectively. IGF-I levels were normal in 48% at the last evaluation on lanreotide SR and in 65% after 3 months on octreotide LAR (P < 0.001). Patients with pre-study pituitary irradiation had lower mean GH and IGF-I concentrations. But the effects of the treatment change did not differ between the irradiated and the nonirradiated patients. In general both drugs were well tolerated. CONCLUSION: Octreotide LAR 20 mg administered once monthly was more effective than lanreotide SR 30 mg administered 2 or 3 times monthly in reducing GH and IGF-I in patients with acromegaly.

Acromegaly↗

PubMed2000

The role of interleukin-6 in the human adrenal gland.

Interleukin (IL)-6 is a potent activator of the hypothalamic-pituitary-adrenal (HPA) axis on all levels in humans, and appears to play a pathogenic role in conditions related to chronic stress and physiological ageing; with physiological ageing showing a similar hormonal and immunological pattern to chronic stress. IL-6 and its receptor IL-6R are co-expressed at similar sites in the human adrenal gland, which seems to be an important source of IL-6 production. In vitro, in primary cultures of adrenal gland cells, chronic exposure to IL-6 stimulates adrenocortical steroid release in a time- and dose-dependent manner. This explains the high systemic cortisol levels in the absence of adequate plasma concentrations of corticotropin (ACTH) observed in patients after long-term treatment with IL-6. It could therefore be concluded that in situations of prolonged stress, when corticotropin-releasing hormone and ACTH release are suppressed by feedback inhibition due to circulating glucocorticoids, IL-6 maintains the elevated glucocorticoid levels by direct stimulation of adrenocortical steroidogenesis via autocrine/paracrine mechanisms.

Adrenal Glands↗

PubMed2000

Long-term anticonvulsant therapy leads to low bone mineral density--evidence for direct drug effects of phenytoin and carbamazepine on human osteoblast-like cells.

Anticonvulsant therapy causes changes in calcium and bone metabolism and may lead to decreased bone mass with the risk of osteoporotic fractures. The two widely used antiepileptic drugs phenytoin and carbamazepine are recognized to have direct effects on bone cells. The aim of our study was to measure the influence of long-term treatment with antiepileptic drugs on bone mineral density (BMD) and to look on direct effects of carbamazepine and phenytoin on human osteoblast-like cells. BMD was measured by dual-energy X-ray absorptiometry. Markers of bone formation and bone resorption were determined in serum and urine. Data of 59 patients were compared to 55 age and sex matched controls. Direct effects of phenytoin and carbamazepine on human osteoblast-like cells were investigated in experimental studies. BMD in the lumbar spine region (L2 through L4) was significantly lower in the patient group as compared to controls (p < 0.0004). At femoral sites BMD was lower in patients, but this difference did not reach statistical significance. The decrease in BMD at both sites was dependent on the duration of therapy. Excretion of pyridinoline crosslinks was markedly increased in the patients. 25-hydroxy-vitamin D3 and 1,25-dihydroxy-vitamin D3 were significantly decreased in patients. Proliferation rate of human osteoblast-like cells was increased by phenytoin in low doses. Both, phenytoin and carbamazepine inhibited cell growth at concentrations equivalent to therapeutic doses for the treatment of epileptic diseases. Our clinical and experimental data indicate that long-term treatment with anticonvulsant drugs leads to a lower BMD. The experimentally observed decrease in bone cell proliferation might be clinically associated with impaired new bone formation. Beside alterations in calcium and vitamin D homeostasis leading to osteomalazia, direct effects of anticonvulsant drugs on bone cells may contribute to the damaging effects on the skeletal system.

Absorptiometry, Photon↗

PubMed2000

Detecting TSH-receptor antibodies with the recombinant TBII assay: technical and clinical evaluation.

We evaluated the technical robustness of the new commercial TBII assay using human recombinant TSH-R, and describe its use for the clinician in the routine laboratory. The human recombinant TSH-R assay (DYNOtest TRAK human) was compared to a conventional TBII assay (TSH-REZAK). Specificity was adjusted at 99.1% for both assays by ROC plot analysis including 113 healthy individuals. Sensitivity in 115 patients with active Graves' Disease (GD) was 98.2% for the DYNOtest TRAK human compared to 68.4% for the TSH-REZAK (p<0.0001). Comparison of the ROC-calculated cut off confirmed the recommended cut-off for the DYNOtest TRAK human, since 11% inhibition of tracer equals 1 IU/L, which is recommended as the grey zone. At the recommended cut-off (2 IU/L, 22% inhibition), the sensitivity is still 93.9% with 100% specificity. The ROC plot-derived cut-off of the TSH-REZAK (4.4%, 2 to 10 U/L) is below the grey zone of 10-15 U/L. At the recommended cut off of 15 U/L, the sensitivity is 43.0% with a specificity of 100%. Both assays showed a good correlation (r = 0.82, p < 0.0001); however, assay comparison revealed a constant bias in favour of the DYNOtest TRAK human. Applying the ROC plot-derived cut-off of 11 % inhibition (1 IU/L) for the DYNOtest TRAK human, we found 15 of 50 patients with autoimmune thyroiditis (AIT) and 6 of 23 patients with goitre (all < 1.5 IU/L). These patients would have been missed using the recommended 2 IU/L. The difference in sensitivity between the DYNOtest TRAK human and the TSH-REZAK was highly significant in the GD group, but not in other groups, indicating that the DYNOtest TRAK human has a higher sensitivity for GD without compromising specificity. In summary, the proposed high sensitivity of the new TBII assay using human recombinant TSH-R could be confirmed with the commercial product. This method offers a clear advantage over conventional TBII assays to confirm or exclude the diagnosis of GD. The recommended cut-off is very stringent, and until we have more information on the clinical relevance of low-level TBII between 1 and 1.5 IU/L, those patients should be monitored for the development of autoimmune thyroid disease.

Autoantibodies↗

PubMed2000

Increased body fat mass and suppression of circulating leptin levels in response to hypersecretion of epinephrine in phenylethanolamine-N-methyltransferase (PNMT)-overexpressing mice.

Epinephrine is a major stress hormone that plays a central role in the control of metabolic function and energy homeostasis. To evaluate the role of epinephrine and the physiological and pathophysiological consequences of sustained elevation of epinephrine on metabolic and endocrine function, we studied several metabolic parameters and circulating leptin levels in a newly developed transgenic mouse model of phenylethanolamine-N-methyltransferase (PNMT) overexpression. A 100-fold overexpression of PNMT and subsequent elevation of epinephrine levels resulted in a marked suppression of circulating leptin levels in the transgenic animals (1.14 +/- 0.05 vs. 2.17 +/- 0.35 ng/ml; P < 0.01), which correlated negatively with plasma epinephrine (r = -0.82; P < 0.05), thus providing evidence for an inhibitory action of epinephrine on leptin production in vivo. In parallel, we found a marked increase in the body fat content of the transgenic animals (12.54 +/- 1.5 vs. 6.22 +/- 0.2%; P < 0.01) that was accompanied by enlarged adipocytes, indicating an increased lipid storage in PNMT transgenic mice. Interestingly, however, transgenic animals had normal body weight and did not exhibit major alterations in carbohydrate metabolism, as evidenced by analysis of random and fasted blood glucose levels, plasma insulin and C peptide levels, and insulin tolerance test. The metabolic alterations observed were not secondary to changes in food intake or increased activity of the hypothalamic-pituitary-adrenal axis, as there were no differences in these parameters. In summary, sustained primary overproduction of epinephrine resulted in suppression of plasma leptin levels and increased lipid storage in the PNMT transgenic mice. The concerted action of the sympathoadrenal system and reduced leptin may contribute to defending energy reservoirs while maintaining a normal body weight, which may be of vital importance under conditions of stress and energy deficiency.

Adipose Tissue↗

PubMed2000

Low frequency of autoantibodies to the human Na(+)/I(-) symporter in patients with autoimmune thyroid disease.

Several studies suggest that the sodium-iodide symporter (NIS) may represent a major autoantigen in autoimmune diseases of the thyroid. The aim of the present paper was to investigate the importance of autoantibodies to human NIS (hNIS-Ab) in patients suffering from Hashimoto's thyroiditis (HT) and Graves' disease (GD). Full-length human NIS (hNIS) was cloned from thyroid tissue, expressed by in vitro transcription and translation in the presence of [(35)S]methionine, and used to analyze autoantibodies in a direct binding assay. The structurally similar glucose transporter, GLUT-2, was produced in the same system as control protein. Autoradiography revealed that full-length hNIS was expressed, recognized by a NIS monoclonal antibody, and strongly bound by some sera from patients with autoimmune thyroid disease, which did not react with the GLUT-2 control protein. Using the 95.2th percentile of healthy controls as threshold for positivity, 19 of 177 (10.7%) patients with GD and 15 of 72 (20.8%) patients with HT had hNIS-Ab, respectively. Applying more stringent cut-off criteria (99.4th percentile of normal controls), hNIS-Ab were found in only 5.6% of patients with GD and 6. 9% of patients with HT. In HT significantly higher hNIS-Ab levels were observed compared with GD and normal controls (P: < 0.001). There was no correlation between hNIS-Ab and TSH receptor antibodies and only a weak correlation to thyroid peroxidase antibodies (P: < 0. 05). Comparison of hNIS-Ab, thyroid peroxidase, and TSH receptor antibodies in individual sera revealed that the additional detection of hNIS-Ab did not increase the diagnostic power for GD or HT. Our data indicate that hNIS is not a major antigen in autoimmune thyroid disease, as it is the target of humoral autoimmunity in only a few patients with GD and HT. The frequency of hNIS-Ab may be lower than that reported in previous studies.

Adolescent↗

PubMed2000

Induction of cellular immunity in a parathyroid carcinoma treated with tumor lysate-pulsed dendritic cells.

BACKGROUND: Cytotoxic T-lymphocyte-mediated tumor immunity against major histocompatibility antigen class II-negative tumors requires help from CD4(+) T-cells. The major antigen presenting cells for CD4(+) cell activation are dendritic cells. Studies in mice and humans have demonstrated the potent capacity of these cells to induce specific antitumor immunity. OBJECTIVE: To control the growth of a metastasized parathyroid carcinoma, by immunizing a patient with tumor lysate and parathyroid hormone-pulsed dendritic cells. DESIGN AND METHODS: Mature dendritic cells were generated from peripheral blood monocytes in the presence of granulocyte/macrophage colony-stimulating factor, interleukin-4 and tumor necrosis factor alpha. Antigen-loaded dendritic cells were delivered by subcutaneous and intralymphatical injections. After five cycles, we added keyhole limpet hemocyanin (KLH) as a CD4(+) helper antigen. RESULTS: After 10 vaccinations, a specific cellular immune response to tumor lysate was observed. In vitro T-cell proliferation assays revealed a dose-dependent stimulation index of 1.8-5.7 compared with 0.9-1.1 before vaccination. In vivo immune response was demonstrated by positive delayed-type hypersensitivity toward tumor lysate. Intradermal injection of tumor lysate resulted in an erythema and induration, suggesting the efficient generation of tumor lysate-specific memory T-cells. CONCLUSIONS: These data indicate that dendritic cell vaccination can induce in vitro and in vivo responses in a highly malignant endocrine carcinoma. Regardless of the clinical outcome of our patient, this approach might be generally applicable to other advanced, radio- and chemotherapy-resistant endocrine malignancies, such as adrenal carcinomas and metastasized medullary and anaplastic thyroid carcinomas.

CD4-Positive T-Lymphocytes↗

PubMed2000

Immunohistochemical and ultrastructural localization of leptin and leptin receptor in human white adipose tissue and differentiating human adipose cells in primary culture.

Leptin is mainly produced in white adipose tissue and acts both at distant sites and locally at the tissue from which it originates. The cellular and subcellular localization of leptin and its receptor (Ob-receptor [Ob-R]) and their relationship to various stages of fat cell maturation have not been characterized as yet. Therefore, we analyzed leptin and Ob-R by using reverse transcriptase-polymerase chain reaction, immunohistochemistry, and ultrastructural immunogold labeling in human white adipose tissue and in human adipocyte cell cultures at early and late stages of differentiation. Both leptin and its receptor were present in mature unilocular fat cells. The thin cytoplasmic rim of the adipocytes exhibited the strongest expression of both leptin and Ob-R. At early stages of differentiating human adipocytes, leptin was mainly expressed in multilocular preadipocytes, whereas the Ob-R was found predominantly on fibroblast-like cells. Other cellular components of human white adipose tissue were characterized by anti-CD31 for endothelial cells, anti-CD68 for macrophages, and antibodies specifically labeling B-cells and T-cells. In addition to fat cells, endothelial cells were immunopositive for the full-length leptin receptor. On the ultrastructural level, leptin was mainly found attached to cellular membranes and in small alveolate vesicle-like structures in the cytoplasm of adipocytes. Leptin was also present on the cell membranes of endothelial cells and macrophages. We conclude that the expression of the Ob-R in human white adipose tissue is not restricted to adipocytes but is present in resident endothelial and immune cells. Ultrastructural localization studies revealed an association of leptin with cell membranes and small vesicles. The cellular and subcellular distribution of leptin and its receptor suggests an important autocrine and paracrine role for leptin in human adipose tissue.

Adipose Tissue↗