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Biomedical subjects

H Dietrich

Publications and source records attributed to H Dietrich.

At least 73 records · Page 4Linked to original sources
PubMed1994

Immunohistochemical analysis of cells infiltrating Rous sarcoma virus-induced tumors in chickens.

The aim of our experiments was the analysis of peripheral blood lymphocytes (PBL) and tumor infiltrating lymphocytes (TIL) in chicken inbred congenic lines, CB line with regressing and CC line with progressing RSV-induced sarcomas. For serological analysis, monoclonal antibodies to CD4, CD8, TCR1, TCR2, MHC class I and class II antigens were used. Significant differences determined by flow cytometry in CD4+ and CD8+ populations of PBL between CB chickens with tumors in progressive phase and CC chickens were not confirmed by means of TIL analysis. TIL were analysed either in suspension prepared from tumors by means of flow cytometry or on cryostat section of tumors. But using the histochemical method we observed more non-specific esterase positive cells in cryostat sections from CB than CC tumors. The role of macrophages in the regression of RSV-induced tumors in CB chickens has to be further analysed.

Animals↗
PubMed1993

Fragrance compounds and essential oils with sedative effects upon inhalation.

Fragrance compounds and essential oils with sedative effects influence the motility of mice in inhalation studies under standardized conditions. A significant drop in the motility of mice was registered following exposure to these fragrances. The same results were achieved when the mice were artificially induced into overagitation by intraperitoneal application of caffeine and subsequently subjected to inhalation of fragrance compounds and essential oils. These results proved the sedative effects of these fragrants via inhalative exposure in low concentrations. Blood samples were taken from the mice after a 1-h inhalation period. Chromatographic and spectroscopic methods were used to detect and characterize the actual effective compounds after solid-phase extraction. Serum concentrations of 42 different substances, including fragrance compounds, were found in low ranges (ng/mL serum). The results contribute to the correct interpretation of the term aromatherapy (i.e., a stimulating or sedative effect on the behaviour of individuals only upon inhalation of fragrance compounds).

Administration, Inhalation↗
PubMed1993

Disturbed immuno-endocrine communication via the hypothalamo-pituitary-adrenal axis in autoimmune disease.

Previous studies in our laboratory demonstrated an altered immuno-endocrine feedback communication via the hypothalamo-pituitary-adrenal (HPA) axis, which may be an important modulatory factor in the development of spontaneous autoimmune thyroiditis in Obese strain (OS) chickens. These birds show a significantly lower, or even absent, increase in serum glucocorticoid levels in response to an intravenous injection of antigen or conditioned medium (CM) from mitogen-stimulated spleen cells known to contain glucocorticoid-increasing factors (GIFs), notably interleukin-1 (IL-1). The present study was aimed at investigating this feedback regulation in animal models with spontaneous systemic autoimmune diseases, such as the UCD-200 chicken, which serves as a model for human scleroderma, and various murine lupus models. In contrast to OS chickens, UCD-200 chickens displayed a nearly normal plasma corticosterone surge in response to CM, and IL-1 was again identified as the primary GIF in CM. Recombinant IL-1 also induced a drastic increase in plasma corticosterone levels in various strains of normal mice. A similar increase was observed in the bacterial lipopolysaccharide-resistant C3H/HeJ strain, thus excluding the possibility of bacterial endotoxin contamination. However, in young lupus-prone (NZB/W)F1 and MRL/MP-lpr mice, a significantly lower increase in plasma corticosterone levels was observed after injection of recombinant IL-1, suggesting a deficient immuno-endocrine communication via the HPA loop in this instance as well. Detailed studies to identify further cytokines with GIF activity in the avian and murine systems showed that both IL-6 and tumor necrosis factor-alpha could induce increased plasma corticosterone levels in mice, but not in chickens. IL-3, IL-8, transforming growth factor-beta, interferon-gamma and granulocyte-macrophage colony-stimulating factor were devoid of GIF activity in both chickens and mice.

Animals↗
PubMed1993

Increased expression of heat shock protein 65 coincides with a population of infiltrating T lymphocytes in atherosclerotic lesions of rabbits specifically responding to heat shock protein 65.

We have shown previously that atherosclerotic lesions can be induced in normocholesterolemic rabbits by immunization with mycobacterial heat shock protein 65 (hsp65), which has a high degree of sequence homology with mammalian hsp60. To investigate a possible relationship between hsp60 expression and the antigenic specificities of infiltrating T cells in the lesion, 38 New Zealand White rabbits were treated either by immunization with recombinant mycobacterial hsp65 or by administration of a 0.2% cholesterol diet. Atherosclerotic lesions were observed after 16 wk, particularly in the aortic arch and arterial bifurcations of rabbits immunized with hsp65 or fed with a cholesterol-rich diet. Hsp65 staining of aortas showed a heterogeneous distribution, and significantly increased staining intensity in atherosclerotic lesions compared to aortic media or adventitia. This abundantly expressed hsp65 was observed in atherosclerotic lesions induced by hsp65 immunization as well as those induced by cholesterol-rich diet alone. Interestingly, a population of the T lymphocytes isolated from all forms of atherosclerotic lesions specifically responded to hsp65 in vitro. IL-2-expanded T cell lines derived from atherosclerotic lesions showed a significantly higher hsp65 reactivity than those developed from peripheral blood of the same donor. Furthermore, levels of circulating antibodies and numbers of spleen cells specifically reacting against hsp65 were elevated in all experimental animals. Flow cytometric analysis of spleen cells showed elevated immune response-associated antigen expression in treated animals. In conclusion, increased hsp65 expression in intimal cells and the presence of hsp65-specific T cells in blood and in atherosclerotic lesions may be important in initiating the development of atherosclerosis and perpetuating the lesions.

Animals↗
PubMed1992

The substance P (NK1) receptor antagonist (+/-)-CP-96,345 causes sedation and motor impairment in Swiss albino mice in the black-and-white box behavioral paradigm.

In order to test the suggested involvement of substance P (NK1) receptors in anxiety, the non-peptide NK1 antagonist (+/-)-CP-96,345 was tested in Swiss albino mice using the black-and-white box behavioral paradigm. Intraperitoneal (+/-)-CP-96,345 dose-dependently decreased the motor activity and the number of exploratory rearings in both the brightly lit and dark compartment as well as the transitions between the compartments, whereas it increased the latency of the initial movement into the dark compartment as well as the time spent in the light section. ED50 or ID50 values ranged from 1.9 to 3.6 mg/kg and Hill slopes from 1.4 to 5.0. (+/-)-CP-96,345 also produced rotatory behavior of no preferred lateralization as well as the Straub phenomenon in some animals. The effects of (+/-)-CP-96,345 (5 mg/kg) were not affected by 2 mg/kg naloxone (i.p.) which was also ineffective when given alone. Thus, (+/-)-CP-96,345 does not display any anxiogenic effect but causes dose-dependent sedation and motor impairment.

Animals↗
PubMed1992

Investigation of ACTH responses of chickens with autoimmune disease.

An altered immunoendocrine feedback regulation within the hypothalamo-pituitary-adrenal axis may modulate the pathogenesis of an avian autoimmune disease. To date studies have been hampered by a lack of reliable, specific, and sensitive methods for determining adrenocorticotropic hormone (ACTH) in chickens. The present study describes the determination of ACTH in plasma of chickens with a commercial radioimmunoassay, the antibody of which binds to the midregion of human ACTH 1-39. The chickens, kept on a 12-hr day and 12-hr night shift with artificial light, showed changes in plasma ACTH concentrations during the light phase with maximum values 8 hr after the light was turned on. ACTH was not measurable after treatment with dexamethasone. Intravenous administration of supernatants from concanavalin A-stimulated spleen cells increased basal plasma ACTH concentrations more than 20-fold within 1 hr. This increase in plasma ACTH was higher and longer lasting in UCD 200 chickens, an animal model for scleroderma, compared with outbred and inbred normal White Leghorn chickens.

Adrenocorticotropic Hormone↗
PubMed1992

Effects of sex steroid analogs on spontaneous autoimmune thyroiditis in obese strain chickens.

Treatment of obese strain chickens, either in ovo or after hatching, with testosterone or various testosterone-derived steroid analogs having no or only weak endocrine activities causes significant protection from spontaneous autoimmune thyroiditis occurring in these birds. This effect is not correlated with the endocrinological properties of these steroids. This observation and similar results in other models for autoimmunity may present a basis for a more selective therapy in human autoimmune diseases in that hormonal side effects no longer preclude this approach.

Age Factors↗
PubMed1992

Induction of arteriosclerosis in normocholesterolemic rabbits by immunization with heat shock protein 65.

Previous studies have established the presence of high numbers of activated T lymphocytes and "aberrant" expression of major histocompatibility complex class II antigens by endothelial and smooth muscle cells in human atherosclerotic lesions, implicating the involvement of a local cellular immune response. The identity of the antigen(s) eliciting this immune response, the extent of their effect, and the atherogenic stage at which they occur remain to be determined. In the present studies, 120 normocholesterolemic New Zealand White rabbits were immunized one or more times with various antigens, with or without adjuvants. The antigens and adjuvants included human or rabbit atherosclerotic lesion proteins, ovalbumin, Freund's complete and/or incomplete adjuvants, recombinant mycobacterial heat shock protein 65 (hsp65), and two hsp-free adjuvants, Ribi complete adjuvant and lipopeptide. In addition, some groups received a high-cholesterol diet. Sixteen weeks after the first immunization the animals were killed, and arteriosclerotic lesions in the intima of the aortic arch were found to have developed only in those animals immunized with antigenic preparations containing hsp, either in the form of whole mycobacteria or as purified recombinant hsp65, although their serum cholesterol levels were normal. No arteriosclerotic changes exceeding those of controls were found in the other groups, irrespective of the antigen used. Immunohistopathologic examination revealed that the lesions contained 20% T cells, 10-30% macrophages, and 10-40% smooth muscle cells. Analysis of the peripheral blood T-lymphocyte proliferative responses revealed that the occurrence of lesions was positively correlated with the presence of hsp65-reactive T cells, suggesting that hsp65 is involved in the induction of arteriosclerotic lesions. Furthermore, combined immunization with hsp-containing material and a cholesterol-rich diet provoked development of significantly more severe atherosclerosis and the appearance of characteristic foam cells. We conclude that an (auto)immune response to hsp may initiate the development of atherosclerosis and that a high blood cholesterol level is only one albeit a very important risk factor.

Animals↗
PubMed1992

[Effects of valerian root oil, borneol, isoborneol, bornyl acetate and isobornyl acetate on the motility of laboratory animals (mice) after inhalation].

The aromatherapeutical use of commercial valerian root oil (Chinese origin) and of pure fragrance compounds--borneol, isoborneol, bornyl acetate (main constituent of the proved valerian root oil) and isobornyl acetate--as potentially drugs with sedative effects after inhalation was investigated in an animal experiment (mice). In additional analyses the mice were treated i.p. by caffeine and distinct sedative effects were observed only by inhalation of the cited substances.

Animals↗
PubMed1991

[Isolation and characterization of colloidal soluble polysaccharides in raspberry juice].

Depending on the preparation method, the colloid content of raspberry juices treated with pectolytic enzymes, can be up to 2.5 g/L. Analysis of the polysaccharides shows that there are in particular, arabinans, arabinogalactans type II and rhamnogalacturonans. While the content of arabinans could be reduced by the action of arabinases, the arabinogalactans and rhamnogalacturonans were not degraded by conventional pectic enzymes. Besides these cell-wall polysaccharides, it was possible to isolate a high molecular-mass beta-glucan, which is thought to originate from Botrytis cinerea. Technical problems in juice clarification or filtration may be caused by this beta-glucan or the high content of residual pectic substances.

Beverages↗
PubMed1991

Phenotypic analysis of skin infiltrates in comparison with peripheral blood lymphocytes, spleen cells and thymocytes in early avian scleroderma.

University of California at Davis line 200 (UCD-200) chickens develop a hereditary connective tissue disease characterized by severe lymphocytic infiltration, vascular occlusion and fibrosis of skin and internal organs. To identify cellular immunological abnormalities in the acute inflammatory disease stage of this animal model for progressive systemic sclerosis (PSS) we investigated the phenotypic characteristics and function of peripheral blood lymphocytes (PBL), spleen cells and thymocytes in comparison with skin infiltrating cells. Immunofluorescence and immunohistochemical analysis using monoclonal antibodies revealed the overwhelming majority of skin infiltrating mononuclear cells in the deeper dermis and subcutaneous tissue to be T cell receptor alpha/beta (TcR2)+/CD3+/CD4+/class II+ cells, a small portion (5-10%) of which were interleukin 2 (IL-2) receptor positive. In contrast, the inflammatory infiltrate in perivascular areas of the papillary dermis was constituted of mainly TcR gamma/delta (TcR1)+/class II- lymphocytes. Only few B cells (T/B cell ratio greater than 5) were detected. These diseased chickens showed significantly reduced percentages and numbers of circulating peripheral T cells exhibiting TcR1, TcR2, CD3, CD4 or IL-2-receptor, probably owing to an increased influx into lymphoid organs and affected tissues. In contrast to healthy chickens, the thymi of UCD-200 animals revealed fewer cells expressing TcR1, TcR2 and class II antigen, suggesting an altered intrathymic maturation of the T cell lineage. Functional in vitro studies showed a significantly decreased T cell mitogen-induced proliferation rate associated with a decreased capacity to produce IL-2 and to express IL-2 receptors. In contrast to the deficient in vitro IL-2 production the sera of UCD-200 chickens contained significant levels of IL-2 bioactivity. The alteration of T lymphocyte physiology in UCD-200 chickens adds, at least in part, to the parallels between this animal model and its human counterpart. These data confirm our hypothesis that the PSS-like disease of UCD-200 chickens includes a numeric and/or functional alteration of peripheral T cell subsets, especially of TcR1 positive cells, in contrast to the pronounced accumulation in the afflicted tissues.

Animals↗
PubMed1991

In-vivo treatment with 5-azacytidine causes degeneration of central lymphatic organs and induces autoimmune disease in the chicken.

In-vitro evidence suggests that DNA methylation may be involved in the development of forbidden immune responses that can result in autoimmune disease. In the present study we examined in-vivo effects of 5-azacytidine (5-azaC), a substance that inhibits DNA methylation, on the immune system and the occurrence of a spontaneous autoimmune disease in the chicken model. We found that (1) treatment of young normal chickens with 1.0 mg/kg 5-azaC on 7 consecutive days caused a rapid degeneration of the central lymphoid organs thymus and bursa; (2) this regimen with 5-azaC apparently inhibited B cell maturation, as the frequency of cytoplasmic Ig+ plasma cells in the bone marrow was found to be significantly reduced, whereas the total number of bone marrow cells was unchanged; and (3) a chronic low-dose (0.5 and 1.0 mg/kg) application of 5-azaC through 6 weeks was found to significantly enhance the spontaneous autoimmune thyroiditis in newly hatched chickens of the Cornell C strain, as determined by anti-thyroglobulin autoantibody titres and histological analysis of thyroid gland infiltration. The possible implications of these data for the generation of pathogenic autoimmune responses are discussed.

Animals↗
PubMed1990

Analysis of the immune-encodrine feedback loop in the avian system and its alteration in chickens with spontaneous autoimmune thyroiditis.

In both mammals and chickens, immunization with exogenous antigens results in a surge of serum glucocorticoid hormone levels concomitant with the antibody response. This effect is mediated by glucocorticoid-increasing factors (GIF) produced by cells of the immune system. In the avian system, GIF appear to act via the hypothalamo-pituitary axis and not directly on the adrenal gland. Interleukin 1 is the main active substance responsible for GIF activity, as shown by molecular sieve and immunoaffinity chromatography studies. In contrast to data from mammals, we found no evidence that interleukin 2 elevates chicken corticosterone. Obese strain chickens with spontaneous Hashimoto-like autoimmune thyroiditis are deficient in their in vivo GIF response. Because no differences were found between autoimmune and healthy chickens in the corticosterone response of the adrenal gland after ACTH administration, and since autoimmune animals are able to react normally to immobilization stress, it is assumed that this deficiency is due to a specific defect rather than a general disturbance in the endocrine system.

Adrenal Glands↗
PubMed1990

[Initial experience with a new blood pump].

A new type of blood pump was tested in calves for 6 hours. The pump consists of a rigid housing with a trochoidal internal surface, an inlet and outlet, and two lateral walls. A two-corner piston rotating on an eccentric shaft, describes a trochoidal path, thus creating a gap seal, the gap measuring a constant 10-35 microns. The pump is driven by a watercooled DC motor. For right ventricular assist, a cannula is inserted into the right ventricle through the right atrium, and into the left ventricle for left ventricular assists. From a total of 10 experiments, two left ventricular assists, two right ventricular assists, and three biventricular assists were evaluated. The pump produced a pulsatile flow of 31 at 70 rpm. Energy requirements were 2.19 watts for left, 2.06 for right, and 7.26 for biventricular assists. Plasma hemoglobin remained as low as 10 mg/dl during monoventricular, and increased during biventricular assists to 20 mg/dl after 3 hours, and returned to 16 mg/dl after 6 hours. From these preliminary results it is concluded that this new rotary blood pump may be suitable as a circulatory assist device.

Animals↗
PubMed1989

Immunogenetic analysis of spontaneous autoimmune thyroiditis of obese strain chickens.

A variety of immunological, endocrinological, and virological abnormalities have been implicated in the etiopathogenesis of spontaneous autoimmune thyroiditis (SAT) of Obese strain (OS) chickens, e.g., a general T cell hyperreactivity, an increased uptake of iodine into the thyroid gland, a diminution of the glucocorticoid tonus, and an OS-specific endogenous virus. In crosses of the close-bred OS B15/B15 subline with the inbred normal CB B12/B12 strain we have studied the mode of inheritance of these aberrations and their putative association with SAT. The results indicate that none of these OS-specific characteristics alone is an absolute prerequisite for the development of thyroid infiltration, which appears to be governed by one autosomal recessive gene.

Animals↗
PubMed1989

Intra-thymic nurse cell lymphocytes can induce a graft-versus-host reaction with high efficiency.

Thymic nurse cells (TNC) are multicellular complexes composed of morphologically intact thymocytes internalized within epithelial cells. Due to their unusual features, they have been suspected to provide an appropriate microenvironment for T-cell repertoire acquisition. In recent functional studies in the chicken system, we have shown that intra-thymic nurse cell-lymphocytes (TNC-L) are highly efficient inducers of a graft-versus-host reaction (GvHR) in an allogeneic chorionallantoic membrane (CAM) assay, manifested by the formation of visible colonies, so-called pocks. Immunohistochemical and electron microscopical assessment of pocks revealed no differences between the cellular components and ultrastructural features of GvHR induced by TNC-L or peripheral blood lymphocytes (PBL). In addition, the stimulation of this local GvHR by interleukin 2 (IL-2) was demonstrated.

Animals↗