| 1. |
- Ahlman, Håkan, 1947, et al.
(författare)
-
The relevance of somatostatin receptors in thyroid neoplasia.
- 1997
-
Ingår i: The Yale journal of biology and medicine. - 0044-0086. ; 70:5-6, s. 523-33
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- 111In-octreotide scintigraphy in patients with persistent medullary thyroid carcinoma (MTC) visualized tumors in about half of the surgically explored sites. Tumor visualization correlated with rapid tumor growth and large tumor volume as judged from calcitonin levels. The 111In concentration ratio between tumor (T) and blood (B) in surgically excised lymph node metastases of MTC showed a large variation, with low values for microscopic and high values for macroscopic metastases in individual patients. Three cases of MTC, Hürthle cell adenoma and papillary thyroid cancer are reported with preoperative scintigraphy, T/B ratios and Northern analyses of the surgical biopsies. Visualization of tumors was possible in the absence of sstr2 (the high affinity receptor for octreotide) with the exception of microscopic tumor growth. T/B values in the patient with Hürthle cell adenoma were similar to those found in the contralateral thyroid lobe with goitre. The relatively high uptake of 111In in benign thyroid conditions probably limits the use of octreotide scintigraphy in the diagnosis of primary tumors. The technique has certain advantages over radioiodine scintigraphy after the surgical treatment of thyroid tumors: no need for withdrawal of thyroxin substitution; a possibility to diagnose metastases of tumors that do not concentrate radioiodine (MTC, Hürthle cell cancer); and complementary information about metastatic sites of non-medullary thyroid cancer (papillary and follicular tumors).
|
|
| 2. |
|
|
| 3. |
- Yeung, Moorix Mo-Wai
(författare)
-
Specific and nonspecific immune mechanisms in human gut : a comparative study of normal and ulcerative colitis intestine
- 1996
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The intestine, with its large mucosal surface area, digests and absorbs food nutrients and maintains a beneficial microbial flora in the colon. Local protective immune responses against intestinal pathogens ensure the survival of the individual. These immune reactions are both specific and non-specific in nature. The intestinal epithelium is single-layered and constantly renewed with differentiating epithelial cells moving from the crypt to the luminal surface. Intraepithelial lymphocytes (IEL) are interspersed between the epithelial cells. Ulcerative colitis (UC) is a life-threatening chronic inflammation affecting colon.In this study three molecules belonging to the carcinoembryonic antigen (CEA) family, namely CEA proper, nonspecific cross-reacting antigen 50/90 (NCA 50/90) and biliary glycoprotein (BGP), were found to be specifically localized to the apical surface of colonic epithelial cells. Full expression of these molecules occurs when the cells reach the upper 1/3 of the crypts and are maintained on the mature cells at the luminal surface. Ultrastructurally, CEA, NCA50/90 and BGP are localized to microvesicles and microfilaments of the fuzzy coat/glycocalyx as well as to the microvilli of the epithelial cells. Their unique localization and documented bacterial binding capacities suggest that they have a role in innate immunity.Functional analysis of IEL in normal jejunum, ileum and colon revealed that IEL are in vivo activated T-lymphocytes expressing mRNA for the cytokines IL-1β, IL-2, IL-8, IFNγ and TNFα and that jejunal IEL have T-cell receptor (TCR)/CD3 dependent cytolytic capacity. As many as 10% of IEL actively produce IFNγ. CD4+TCRαβ+IEL, CD8+TCRαβ+IEL and CD4-CD8-TCRαβ+IEL all had a TH1/cytotoxic cytokine profile. IEL could be further stimulated in vitro to express IL-10, TNFβ and TGFβ1, to proliferate and to secrete IFNγ. Thus, active protection and/or regulation of the epithelium via cell-mediated immune reactions are prominent in the gut.UC colon was characterized by a marked lymphocyte infiltration in the lamina propria, 10-50 times the normal level. Most lymphocytes were present in follicle-like cell aggregates containing both T- and B-cells. An unexpected finding was that γδT-cells constituted about 15% of the cells in the aggregates. Such cells are only found intraepithelially in normal gut. γδT-cells of both the intestinal- (TCR-Vδ1/Vγ8) and blood type (TCR-Vδ2/Vγ9) were seen. T-cells in UC colon were activated but nonproliferating and had a down-regulated TCR/CD3 complex. RT-PCR and quantitative immunohistochemistry for cytokine mRNA (n=11) and protein respectively, revealed that the T-cells in UC colon did not produce IL-2, in marked contrast to T-cells in normal colon and to ileal T-cells from UC patients. This was a selective defect since TNFα, IFNγ, IL-1β, IL-8 and TGFβ1 were similarly expressed in normal colon. No TH2 cytokines were seen. Lamina propria leukocytes in UC colon expressed IL-6, a cytokine not found in normal colon. The epithelial cells of UC colon were activated expressing MHC class II antigens, heat shock proteins and the co-stimulatory molecule B7.1/CD80.Our study demonstrates that UC is an immunological disease. The immunopathological picture seen in UC colon probably reflects an inappropriate down-regulation of local immune responses perhaps due to a selective loss of the key cytokine IL-2 in a situation of extreme antigenic stress.
|
|
| 4. |
|
|
| 5. |
|
|
| 6. |
|
|
| 7. |
|
|
