Two hypotheses, the hypothalamic and pituitary hypotheses, have been suggested concerning the pathogenesis of pituitary adenoma. The recent demonstration of the monoclonality of most human pituitary adenomas has led to wider acceptance of the pituitary hypothesis, which suggests that pituitary adenoma results from monoclonal expansion of a single adenohypophyseal cell with subcellular abnormalities. Meanwhile, the role of hypothalamic hormones in the development of pituitary adenoma has recently attracted the attention of investigators. The present paper discusses the expression of growth hormone-releasing hormone (GHRH) in somatotroph adenoma, and corticotropin-releasing hormone (CRH) in corticotroph adenoma. Locally generated hypothalamic hormones and expression of associated receptors in human pituitary adenoma cells play significant roles in autocrine/paracrine regulation of pituitary hormone production.
Amplification and deletion are the most common mechanisms leading genes to gene deregulation in breast cancer, but the relevance, the role and timing of most of the described genetic abnormalities are still unclear. The significance and usefulness of those genetic abnormalities will have to be established by the use of reliable and reproducible methodologies. In this study, we used the advanced technique of laser capture microdissection to obtain pure tumor cell populations and normal epithelium in paired breast tissue samples from the same patient, and submitted them to further analysis by real-time quantitative RT-PCR for a rapid, objective and reliable quantification of even small abnormalities. We will also introduce and recommend a simple staining method and a suitable thickness of section for LCM and quality RNA extraction from the tissue samples. We believe that this method will provide more detailed evidence of gene expression in the study of cancers, especially in multi-step cancer carcinogenesis.
VIP-like immunoreactive (VIP-LIR) and vasopressin-like immunoreactive (VP-LIR) neuronal elements located in the monkey suprachiasmatic nucleus (SCN) were investigated by light and electron microscopic immunocytochemistry. Both populations of neurons in the monkey SCN show a similar distribution to those of the rat except for some subtle differences. In addition to the ordinary distribution of VIP-LIR and VP-LIR neurons, VIP-LIR neurons of similar or some smaller size to those in the ventrolateral portion of the nucleus were also observed in the periventricular nucleus adjacent to the third ventricle. VP-LIR neurons with similar size and either strong or weak immunoreactivity compared with those located in the dorsomedial area were detected in the periventricular nucleus in which magnocellular VP-LIR neurons with strong immunoreactivity were distributed. Both VIP-LIR and VP-LIR neuronal perikarya were found to contain well developed cell organelles such as rER and mitochondria as well as immunoreactive dense granules. VIP-LIR neuronal perikarya were generally surrounded by astroglial processes. However, non-immunoreactive axons were frequently found to make synaptic contact with VIP-LIR dendrites or dendritic spines. Thus the VIP-LIR neurons are thought to receive neuronal inputs from other parts of CNS mainly from the dendrites or dendritic spines. VIP-LIR and VP-LIR axons were seen to form synapses on non-immunoreactive dendrites. VIP-LIR axons were also found to form axo-axonic synapses on non-immunoreactive axons. Synaptic contacts between VIP-LIR neuronal elements were also occasionally observed. The present study has demonstrated that both the VIP-LIR and VP-LIR neurons are at least partly intrinsic neurons in the SCN, and also projecting elements to the other neurons of the CNS.
Calcitonin (CT) is a peptide hormone synthesized and secreted by the parafollicular (C) cells of the thyroid. Little is known about the mechanisms controlling proliferation of C cells by other humoral factors including CT, and there is no report that CT suppresses C cell proliferation. The effects of short-term administration of CT on C cell growth fraction were analyzed using BrdU and CT double immunohistochemical method in the rat thyroid. Continuous administration of 0.4 IU/kg and 40 IU/kg synthetic salmon CT for 14 days induced dose-dependent suppression of BrdU labeling number of C cells without decrease of C cell to the total thyroid follicular cell ratio. These results suggest that exogenous CT may induce negative feedback to C cell proliferation in the thyroid.
Our previous studies of pancreatic tumors have demonstrated that invasive ductal carcinoma (IDC) usually showed expression of MUC1 (membrane bound type mucin) detected by monoclonal antibody DF3, whereas intraductal papillary-mucinous neoplasm (IPMN) showed no expression of MUC1. In the present study, we examined 50 IDCs, and 63 IPMNs which were morphologically classified into two histological subtypes, "dark cell type" (IPMN-D, 27 cases) and "clear cell type" (IPMN-C, 36 cases). Patients with either type of IPMN showed significantly better survival than those with IDC. To clarify the relationship of the expression patterns of mucins with their biological behavior, we examined the expression profiles of various glycoforms of membrane mucin (MUC1) and secretory mucin (MUC2, MUC5AC and MUC6) in the neoplasms using immunohistochemistry. IDCs showed high expression of all the glycoforms of MUC1 (66%-98%). In contrast, IPMNs-D showed no or low expression of all the glycoforms of MUC1 (0%-4%), while IPMNs-C showed low expression of poorly glycosylated MUC1 (3%-6%), but expression of sialylated MUC1 (41%) and fully glycosylated MUC1 (69%). Expression of MUC2 was negative (0%) in IDC, high (96%) in IPMN-D and low (3%) in IPMN-C. MUC5AC was highly expressed in all types. MUC6 expression was higher in IPMNs-C (92%) than in IDCs (56%) and IPMNs-D (37%). In conclusion, the present study demonstrated that IDCs showed high expression of all the glycoforms of MUC1, and also that two types of IPMNs showed different expression patterns of glycosylated MUC1 as well as MUC2 and MUC6. These different expression patterns of mucins may be related with the malignancy potential of pancreatic neoplasms.
The results obtained in the present study demonstrated the precise localization and characterization of glycoconjugates in the disseminate prostate gland of the wild boar, using glycohistochemical methods including lectin techniques in light microscopy. According to the present results, it was apparent that glycoconjugates with neutral and acidic groupings were contained in the secretory epithelial cells and luminal secretions. In these glycoconjugates, a series of saccharide residues were visualized such as α-D-glucose, α-D-mannose, α-L-fucose, β-D-galactose, N-acetyl-D-galactosamine, N-acetyl-D-glucosamine, and N-acetyl-neuraminic acid (sialic acid). In addition, an abundance of glycoconjugates with terminal sialic acids was revealed in the peripheral parts of the prostate gland, as compared with its central parts. The terminal saccharide residues of glycoconjugates were more abundant in Siaα2-6Gal/GalNAc than those in Siaα2-3Galβ1-4GlcNAc. Furthermore, some specifically MAA reactive acinous cells were detected in the glandular epithelium. The present histochemical results provide useful information regarding the close correlation between the physiological role of the disseminate prostate gland and the glandular glycoconjugates in the wild boar.
The localization of NADP-dependent isocitrate dehydrogenase (cytosolic type, ICD2) in rat kidney peroxisomes was studied using an immunoelectron microscopic technique. Rat kidneys were perfusion-fixed in a fixative consisting of 4% paraformaldehyde, 0.2% glutaraldehyde and 0.1 M Hepes-KOH buffer (pH 7.4) for 10 min. Fixed tissue slices were embedded in LR White resin. Thin sections were stained for ICD2 with a combination of anti-ICD2 and protein A-gold probe (15 nm). Signals for ICD2 were found to be present in the peroxisomes of the proximal tubules but not in the cytoplasmic matrix. Within the peroxisomes, ICD2 was detected in the peripheral dense matrix where catalase was present but not in the central clear matrix to which D-amino acid oxidase was confined. The results showed that in the rat kidney ICD2 was confined to the peroxisomes and located in the peripheral dense matrix as catalase.
Dihydropyrimidine dehydrogenase (DPD) is a rate-limiting enzyme in the catabolism of 5-fluorouracil (5-FU). Previous studies have suggested that high enzyme activities and mRNA levels of DPD are involved in the resistance of cancers to 5-FU. For immunohistochemically demonstrating the tumor resistance to 5-FU, we determined the most suitable and reproducible condition of antigen retrieval for DPD localization in formalin-fixed, paraffin-embedded sections, and analyzed DPD expression in various types of normal and cancerous tissues. Pressure cooking in ethylenediaminetetraacetic acid, pH 8.0, was the best choice for retrieving the antigenicity of DPD. In normal tissues, DPD immunoreactivity was consistently detected in squamous epithelia, hepatocytes, Clara cells, ductal/glandular epithelia of various organs, myoepithelial cells, and non-epithelial cells such as macrophages, plasma cells, and part of the endothelial cells and fibroblasts. DPD was strongly expressed in adenocarcinomas of the lung, gallbladder and pancreas, hepatocellular carcinomas, and transitional cell carcinomas of the urinary bladder. Squamous cell carcinomas of the pharynx and lung were moderately reactive. Carcinomas of the breast and stomach revealed less consistent and less intense reactivity. Colorectal adenocarcinomas were not immunoreactive. The polyclonal antibody gave a broader and stronger reactivity than the monoclonal antibody KM1915, particularly in the normal epidermis and skin appendage as well as in squamous cell carcinomas and gastric cancers. The present results hopefully contribute to further investigations, in which the immunohistochemical demonstration of DPD is utilized as a tool of tailor-made chemotherapy for selecting of patients with cancer resistant to 5-FU and its derivatives.
The expression of parathyroid hormone/parathyroid hormone-related protein (PTH/PTHrP) receptor in the mandibular condyles from sham-operated (Sham), ovariectomized (OVX), and OVX with 17 β-estradiol (E2)-treated (OVX+E 2) rats was investigated immunohistochemically with computer-aided image analysis. Western blot analysis for the receptor was also confirmed using these experimental cartilage models. The PTH/PTHrP receptor was preferentially localized in the hypertrophic chondrocytes throughout, and Western blot analysis revealed the protein expression in all of these cartilage models examined. Notably, OVX induced an enlargement of the hypertrophic chondrocytes, with larger indices of staining intensity and area as revealed by the image analysis; and E2 treatment of OVX rats restored the values to nearly those of the Sham group. These findings suggest that the hypertrophic chondrocyte is a key regulatory site for the chondrocyte maturation and eventual matrix ossification in response to serum E2 via the participation of PTH/PTHrP receptor in the adult rat mandibular condylar cartilage.