Pathophysiological characteristics of non-alcoholic steatohepatitis-like changes in cholesterol-loaded type 2 diabetic rats

Spontaneously Diabetic Torii (SDT) fatty rats, a new obese diabetic model, reportedly presented with features of non-alcoholic steatohepatitis (NASH) after 32 weeks of age. We tried to accelerate the onset of NASH in SDT fatty rats using dietary cholesterol loading and noticed changes in the blood choline level which is expected to be a NASH biomarker. Body weight and biochemical parameters were measured from 8 to 24 weeks of age. At 16, 20, 24 weeks, pathophysiological analysis of the livers were performed. Hepatic lipids, lipid peroxides, and the expression of mRNA related to triglyceride (TG) synthesis, inflammation, and fibrosis were evaluated at 24 weeks. Hepatic fibrosis was observed in SDT fatty rats fed cholesterol-enriched diets (SDT fatty-Cho) from 16 weeks. Furthermore, hepatic lipids and lipid peroxide were significantly higher in SDT fatty-Cho than SDT fatty rats fed normal diets at 24 weeks. Hepatic mRNA expression related to TG secretion decreased in SDT fatty-Cho, and the mRNA expression related to inflammation and fibrosis increased in SDT fatty-Cho at 24 weeks. Furthermore, SDT fatty-Cho presented with increased plasma choline, similar to human NASH. There were no significant changes in the effects of feeding a cholesterol-enriched diet in Sprague-Dawley rats. SDT fatty-Cho has the potential to become a valuable animal model for NASH associated with type 2 diabetes and obesity.

A new objective histological scale for studying human photoaged skin

BACKGROUND

A quantitative understanding of the histological alteration of the skin is important for assessing the severity of photoaging.

METHODS

We performed Elastica-van Gieson staining and immunohistochemistry for decorin on 34 facial skin sections. We evaluated the alteration of collagen fibers and decorin (a modulator for collagen fibrillogenesis), according to the 5 grades of morphological change in elastic fibers that was established by Kligman (1969). The objectivity of a stage (Stages I-VI), which was established in this study, was evaluated using weighted kappa statistical analysis based on the degree of agreement in stage determination by 11 observers using a blind procedure. Correlation between the crow's-feet-area wrinkles grades of another 26 women and stages was also analyzed.

RESULTS

The initial alteration of elastic fibers was observed in the deep dermis. Decorin was not detected in very severely altered skin. Based on the combination of changes in the elastic fibers, collagenic fibers, and decorin, skin tissues were categorized into 6 stages according to severity. The statistical analysis showed almost perfect agreement between observers. Significant positive correlation between stages and wrinkle scores was found.

CONCLUSIONS

We propose a new objective histological scale that is useful for assessing the severity of photoaging.

Ki-67 and minichromosome maintenance-7 (MCM7) expression in canine pituitary corticotroph adenomas

Pituitary-dependent hyperadrenocorticism (PDH) caused by pituitary corticotroph adenoma is a common endocrine disorder in dogs. The ratio between pituitary height and the area of the brain (P/B) has been used to evaluate the pituitary size. A P/B ratio > 0.31 indicates an enlarged pituitary, whereas a P/B ratio ≤ 0.31 indicates a nonenlarged pituitary. The aim of this study was to investigate the expression of proliferation markers Ki-67 and minichromosome maintenance-7 (MCM7) in canine corticotroph adenomas in enlarged and in nonenlarged pituitaries and to evaluate their relation with the size of canine pituitary corticotroph adenomas. Ki-67 and MCM7 expression in ACTH-positive tumor cells was determined by dual-labeling immunohistochemistry in resected corticotroph adenomas from 15 dogs with PDH. The mean ± SD Ki-67 labeling index (LI) was 0.55% ± 0.59% in corticotroph adenomas with nonenlarged pituitaries and 1.6% ± 0.6% in adenomas with enlarged pituitaries. The MCM7 LI in corticotroph adenomas with nonenlarged pituitaries and in adenomas with enlarged pituitaries was 2.9% ± 2.2% and 10.9% ± 3.7%, respectively. The Ki-67 LI and MCM7 LI were significantly greater in the adenomas with enlarged pituitaries than in the adenomas with nonenlarged pituitaries (P < 0.01 and P < 0.01, respectively). The MCM7 LI was significantly greater than the Ki-67 LI in adenomas (P < 0.01). The Ki-67 LI was positively correlated with the MCM7 LI (r = 0.820, P < 0.01), and the P/B ratio was positively correlated with the Ki-67 LI (r = 0.560, P = 0.03) and the MCM7 LI (r = 0.854, P < 0.01). In conclusion, canine corticotroph adenomas in enlarged pituitaries show greater proliferation potential than do adenomas in nonenlarged pituitaries. MCM7 expression was significantly greater than Ki-67 expression in canine pituitary corticotroph adenomas. Thus, MCM7 may be superior to Ki-67 as a proliferation marker in pituitary tumors.

Abstract P6-08-02: Comparative Analysis between Primary and Secondary in Breast Tumors by Polymorphysim of Androgen Receptor Gene and Mitochondria D-Loop Somatic Mutation

Background: It has not been fully understood how we can differentiate a new primary breast cancer from a recurrent tumor, when second tumor arises in ipsilateral breast after the surgery for primary breast cancer. To address this research question, we estimate the usefulness of a method analyzing polymorphism of androgen receptor gene and mitochondrial D-loop somatic mutation.

Materials and methods: 1) Select patients: Among the 558 patients who received the breast conservative surgery in Tokai University Hospital (1991∼2004), 9 ipsilateral breast tumors and 11 contralateral breast tumors were submitted for the analysis. 2) Formalin-fixed paraffin-embedded (FFPE) sections of non-neoplastic lymph node were examined whether polymorphism of AR gene present or not. 3) When polymorphism of AR gene in non-neoplastic lymphoid tissue were demonstrated, ipsilateral and contralateral breast cancers were further examined. 4) When AR gene in breast cancers on same allele in primary and secondary tumors, FFPE sections were further analyzed by mutaion analysis of mitochondrial D-loop region.

Results: 1) Polymorphism of AR was demonstrated in 8/9 (88.9%) and 9/11 (81.8%) non-neoplastic lymph nodes obtained from the patients who had ipsilateral and contralateral breast tumor, respectively. 2) Only 2 of 8 ipsilateral breast cancers demonstrated AR polymorphism different from primary cancer. In contrast, 6 of 9 contralateral breast cancers had different polymorphism for AR from primary breast cancers. 3) Analysis of mitochondrial D-loop mutation showed that 8 seconary ipsilateral cancers had different mutation in 3/8 (37.5%), identical mutation in 3/8 (37.5%), and no mutation in 2/8 (25.0%).

Results of analysis for ipsilateral secondary breast cancers

Conclusion: Half of the ipsilateral in breast secondary tumors were estimated as new primary lesions by molecular estimation. Combination analyses of AR gene polymorphism and mitochondrial D-loop somatic mutation unable us to distinguish between true recurrent or new primary cancers.

Overexpression of E2F-5 correlates with a pathological basal phenotype and a worse clinical outcome

The purpose of the present study is to identify genes that contribute to cell proliferation or differentiation of breast cancers independent of signalling through the oestrogen receptor (ER) or human epidermal growth factor receptor 2 (HER2). An oligonucleotide microarray assayed 40 tumour samples from ER(+)/HER2(−), ER(+)/HER2(+), ER(−)/HER2(+), and ER(−)/HER2(−) breast cancer tissues. Quantitative reverse transcriptase PCR detected overexpression of a cell cycle-related transcription factor, E2F-5, in ER-negative breast cancers, and fluorescence in situ hybridisation detected gene amplification of E2F-5 in 5 out of 57 (8.8%) breast cancer samples. No point mutations were found in the DNA-binding or DNA-dimerisation domain of E2F-5. Immunohistochemically, E2F-5-positive cancers correlated with a higher Ki-67 labelling index (59.5%, P=0.001) and higher histological grades (P=0.049). E2F-5-positive cancers were found more frequently in ER(−)/progesterone receptor (PgR)(−)/HER2(−) cancer samples (51.9%, P=0.0049) and in breast cancer samples exhibiting a basal phenotype (56.0%, P=0.0012). Disease-free survival in node-negative patients with E2F-5-positive cancers was shorter than for patients with E2F-5-negative cancers. In conclusion, we identify, for the first time, a population of breast cancer cells that overexpress the cell cycle-related transcription factor, E2F-5. This E2F-5-positive breast cancer subtype was associated with an ER(−)/PgR(−)/HER2(−) status, a basal phenotype, and a worse clinical outcome.

Loss of heterozygosity alterations associated with progesterone therapy in endometrial hyperplasia and adenocarcinoma

Loss of heterozygosity (LOH) was analyzed in four patients with endometrial hyperplasia (EH) with atypia (two patients) and without atypia (two patients) and in five patients with endometrial adenocarcinoma (EAC) to clarify the clinicopathologic relationship between genetic alterations and hormone therapy. Each patient was initially administered high-dose medroxyprogesterone acetate (MPA) as a uterine-sparing treatment. The five microsatellite markers used to analyze LOH were at chromosomal loci 8p22.1, 8p21, 8p21.3, 8p22, and 8p22. DNA was extracted from paraffin-embedded sections before, during, and after MPA therapy using laser capture microdissection. As a result, LOH was more frequently detected after MPA therapy (overall ratios were 16, 17, and 29% before, during, and after MPA therapy, respectively). LOH is more easily detected in EH loci than in EAC loci before MPA. For EAC, initial LOH detection on chromosome 8 may be related to an incomplete response to MPA, but negative LOH does not guarantee a favorable treatment outcome. For EH or atypical endometrial hyperplasia, it is unknown whether LOH alteration associated with MPA therapy is related to atypia of the disease.

Loss of heterozygosity alterations associated with progesterone therapy in endometrial hyperplasia and adenocarcinoma

Loss of heterozygosity (LOH) was analyzed in four patients with endometrial hyperplasia (EH) with atypia (two patients) and without atypia (two patients) and in five patients with endometrial adenocarcinoma (EAC) to clarify the clinicopathologic relationship between genetic alterations and hormone therapy. Each patient was initially administered high-dose medroxyprogesterone acetate (MPA) as a uterine-sparing treatment. The five microsatellite markers used to analyze LOH were at chromosomal loci 8p22.1, 8p21, 8p21.3, 8p22, and 8p22. DNA was extracted from paraffin-embedded sections before, during, and after MPA therapy using laser capture microdissection. As a result, LOH was more frequently detected after MPA therapy (overall ratios were 16, 17, and 29% before, during, and after MPA therapy, respectively). LOH is more easily detected in EH loci than in EAC loci before MPA. For EAC, initial LOH detection on chromosome 8 may be related to an incomplete response to MPA, but negative LOH does not guarantee a favorable treatment outcome. For EH or atypical endometrial hyperplasia, it is unknown whether LOH alteration associated with MPA therapy is related to atypia of the disease.

Phospholipase C-dependent hydrolysis of phosphatidylcholine hydroperoxides to diacylglycerol hydroperoxides and its reduction by phospholipid hydroperoxide glutathione peroxidase

We have shown that 1,2-diacylglycerol hydroperoxides activate protein kinase C (PKC) as efficiently as does phorbol ester [Takekoshi S, Kambayashi Y, Nagata H, Takagi T, Yamamoto Y, Watanabe K. Activation of protein kinase C by oxidized diacylglycerol. Biochem Biophys Res Commun 1995; 217: 654-660]. 1,2-Diacylglycerol hydroperoxides also stimulate human neutrophils to release superoxide whereas their hydroxides do not [Yamamoto Y, Kambayashi Y, Ito T, Watanabe K, Nakano M. 1,2-Diacylglycerol hydroperoxides induce the generation and release of superoxide anion from human polymorphonuclear leukocytes. FEBS Lett 1997; 412: 461-464]. One of the proposed mechanisms for the formation of 1,2-diacylglycerol hydroperoxides is the hydrolysis of phosphatidylcholine hydroperoxides by phospholipase C (PLC). To confirm this hypothesis, we incubated 1-palmitoyl-2-linoleoyl-phosphatidylcholine (PLPC) liposomes containing PLPC hydroperoxides (PLPC-OOH) with Bacillus cereus PLC and found 1-palmitoyl-2-linoleoylglycerol (PLG) and its hydroperoxide (PLG-OOH) were produced. PLC hydrolyzed the two substrates without preference, as the yields of PLG and PLG-OOH were the same even though cholesterol was incorporated into liposomes to increase bilayer integrity. Phospholipid hydroperoxide glutathione peroxidase (PHGPX) reduced PLG-OOH to its hydroxide in the presence of glutathione while the conventional cytosolic glutathione peroxidase did not. These data suggest that PLC hydrolyzes oxidized biomembranes to give 1,2-diacylglycerol hydroperoxides for PKC stimulation but PHGPX may prevent neutrophil stimulation by reducing 1,2-diacylglycerol hydroperoxides to their hydroxides.

Expression and localization of leptin receptor in the normal rat pituitary gland

Leptin receptor (leptin-R) is a polypeptide consisting of a single transmembrane-spanning component. Recent studies performed by reverse transcriptase polymerase chain reaction (RT-PCR) have shown the production of leptin-R in various tissues including the pituitary, hypothalamus and reproductive organs. The localization of leptin-R protein in the pituitary gland, however, has not been extensively studied. This study deals with the expression of leptin-R in the normal rat pituitary gland, which was disclosed primarily in the plasma membrane fraction by immunoblotting and immunohistochemical staining methods. Double immunohistochemical staining revealed that the colocalization of leptin-R and anterior pituitary hormone expression was seen mainly in growth hormone (GH)-secreting cells (97.4 +/- 1.3%; GH-positive cells/leptin-R-positive cells), but in less than 1% of prolactin (PRL)-, adrenocorticotropic hormone (ACTH)-, thyroid-stimulating hormone-beta (TSH beta)- and follicle-stimulating hormone-beta (FSH beta)/luteinizing hormone-beta (LH beta)-positive cells. In contrast, leptin was localized most frequently in FSH beta/LH beta- and less frequently in TSH beta-positive cells. The above findings suggest that, in the rat anterior pituitary gland, there are paracrine relationships between leptin-producing cells and cells with leptin-R, which may regulate the function of GH cells.

Differentiation of necrotic cell death with or without lysosomal activation: application of acute liver injury models induced by carbon tetrachloride (CCL4) and dimethylnitrosamine (DMN)

We investigated the relationship between DNA degradation and lysosome activity (loss of lysosomal integrity) in necrotic cell death induced by carbon tetrachloride (CCl4) and dimethylnitrosamine (DMN): coagulation necrosis and hemorrhagic necrosis, respectively. TdT-mediated dUTP-biotin nick end-labeling (TUNEL) and enzyme histochemistry for acid phosphatase were performed in both models and results were analyzed by light microscopy, electron microscopy, and confocal laser scanning microscopy (CLSM). In the CCl(4)-injected liver, TUNEL staining was closely associated with release of lysosomal enzymes into the cytoplasm, and intranuclear deposition of lysosomal enzymes took place at an early stage of subcellular damage. In the DMN-injected liver, TUNEL-positive nuclei tended to have well-preserved lysosomes and centrally localized TUNEL signals. It was assumed that acute hepatocellular damage in the CCl4-injected liver would be characterized by necrotic cell death with lysosome activation and that damage in the DMN-injected liver would be necrotic cell death without lysosome activation. In the DMN-injected liver, DNA degradation may be selectively induced in the nuclear center, in which heterochromatin (including inactive chromatin) is believed to be a target. We concluded that necrotic cell death, i.e., DNA degradation, would be at least divided into two types, with/without association with lysosome activation, represented by necrotic cell death in the CCl4-injected liver and that in the DMN-injected liver.

Electron microscopic observation of intracellular expression of mRNA and its protein product: technical review on ultrastructural in situ hybridization and its combination with immunohistochemistry

In situ hybridization (ISH) at the electron microscopic (EM) level is essential for elucidating the intracellular distribution and role of mRNA in protein synthesis. Three different approaches have been applied by the investigators in this EM-ISH study: preembedding method; non-embedding method using ultrathin frozen sections; and postembedding method. In order to obtain satisfactory morphological preservation and retain the messages, we routinely utilized 6 microns-thick frozen sections fixed in 4% paraformaldehyde for the preembedding method and tissues embedded in LR White resin for the postembedding method. The hybridization signal intensity by the postembedding method was lower, and non-specific signals were relatively frequent, in comparison with the preembedding method. The preembedding method thus appears to be easier and better than the postembedding method from the viewpoint of applicability and preservation of mRNA, although quantitative analysis of the expression of mRNA is rather difficult in the preembedding method. EM-ISH is considered to be an important tool for clarifying the intracellular localization of mRNA and the exact site of specific hormone synthesis on the rough endoplasmic reticulum. The simultaneous visualization of mRNA and encoded protein in the same cells using preembedding EM-ISH and subsequent postembedding immunoreaction with protein A colloidal gold complex is also described. This ultrastructural double-staining method for mRNA and encoded protein can be expected to provide an important clue for elucidating the intracellular correlation of mRNA translation and secretion of translated protein.

Distribution of adrenomedullin (AM), proadrenomedullin N-terminal 20 peptide, and AM mRNA in the rat gastric mucosa by immunocytochemistry and in situ hybridization

Adrenomedullin (AM) is a novel vasorelaxant peptide isolated from pheochromocytoma. Proadrenomedullin N-terminal 20 peptide (PAMP) is a hypotensive peptide generated by posttranslational enzymatic processing of a 185-amino acid pro-AM molecule, the same precursor as AM. In this study, we investigated localizations of these peptides by immunocytochemistry and AM mRNA by non-radioisotopic in situ hybridization followed by the streptavidin and biotin complex (ABC) method and catalyzed signal amplification (CSA) in the rat adrenal medulla and gastric mucosa. In the gastric mucosa, both AM- and PAMP-like immunoreactivities were found in the neuroendocrine cells, but PAMP-positive cells were more abundant than AM-positive ones. By immunoelectron microscopy, AM and PAMP were localized exclusively in the secretory granules. The distribution pattern of AM mRNA-positive cells, only a limited portion of which had AM and/or PAMP, was also similar to that of the two peptides. But AM mRNA was detected also in a few epithelial cells as well as neuroendocrine cells. The two peptides might play an important role in the control of local circulation in the rat stomach.

Antioxidative action of flavonoids, quercetin and catechin, mediated by the activation of glutathione peroxidase

Antioxidative action of flavonoids have been attracted attention of many investigators and a good deal of studies on it were reported. While their interests were mostly centered to the direct scavenging action of flavonoids against free radicals and active oxygen species, we expected that the interaction of flavonoids and intracellularly occurring antioxidative agents such as glutathione peroxidase (GSH-PO) could synergistically enhance their antioxidative activities. For this purpose, cultured rat hepatocytes (BL-9), which are highly expressing GSH-PO, were employed. One group of the cells were cultured with Se deficient media (Se(-) cells) to diminish the activity and the expression of GSH-PO protein and mRNA, and the other group was cultured with Se supplemented media (Se(+) cells). The oxidative cell damage was induced by the addition of H2O2 and two representative antioxidative flavonoids, quercetin and catechin, were added to the media to test their cytoprotective action. In Se(+) cells, the remarkable cytoprotective activity of those flavonoids were confirmed, whereas none of such activity was evidenced in Se(-) cells. It was proved that the intracellular antioxidative function of flavonoids requires the interaction with GSH-PO, at least in the cells expressing the enzyme. Interestingly, the flavonoid activated GSH-PO clearly, and its mechanism is discussed.

An improved ultrastructural double-staining method for rat growth hormone and its mRNA using LR White resin: a technical note

An improved new method for the simultaneous visualization of mRNA and encoded protein in LR White resin-embedded specimens is described. This pre-embedding electron microscopical in situ hybridization (procedure) localized rat growth hormone mRNA specifically as high electron-density products on the polysomes of the rough endoplasmic reticulum. A subsequent post-embedding immunoreaction, using protein A colloidal gold particles, identified growth hormone as gold particles both in the cisternae of the rough endoplasmic reticulum and on the secretory granules. In our previous report, we used Epon resin for tissue embedment, which required an etching process using hydrogen peroxide or sodium periodate for immunoreactivity retrieval. In general, osmification and embedment in Epon resin are reported to decrease the immunoreactivity of the targeted protein, and the etching process using hydrogen peroxide or sodium periodate results in deosmification and shades off the signals of mRNA. To resolve these problems, we have recently used LR White resin for tissue embedment. In LR White resin-embedded tissues, retrieval of immunoreactivity using hydrogen peroxide or sodium periodate is not required, and, therefore, the gradation of the signals of mRNA can be avoided.

Expression of glutathione-peroxidase (GSH-PO) in the rat ventral prostate--effect of castration and administration of testosterone

Immunolocalization of glutathione-peroxidase (GSH-PO), apoptosis and bcl-2 protein in the rat ventral prostate was investigated in the presence or absence of androgen. Male Sprague-Dawley rats were divided into four experimental groups. Group 1 consisted of intact controls. In group 2, rats were sacrificed two days after castration. In groups 3 and 4, rats were administered subcutaneously 1 mg/animal of testosterone-propionate daily for three or seven days at two days after castration. The intensity of GSH-PO staining in the glandular epithelial cells of the ventral prostate was remarkably decreased after castration (Group 2), and it clearly recovered when testosterone was administered (Groups 3 and 4) to the castrated rats. The prostatic GSH-PO mRNA levels were diminished in the castrated rat ventral prostate but greatly increased by testosterone (Groups 3 and 4). Furthermore, castration (Group 2) induced apoptosis in the prostatic glandular epithelial calls and the apoptosis was reduced by testosterone-administration (Groups 3 and 4) to the castrated rats. In groups 3 and 4, expression of bcl-2 protein was clearly detected in the glandular epithelial cells of the ventral prostate. These findings strongly suggested that expression of GSH-PO and bcl-2 protein in the glandular epithelial cells of the rat ventral prostate is testosterone-dependent.

Modulation of protein kinases and microtubule-associated proteins and changes in ultrastructure in female rat pituitary cells: effects of estrogen and bromocriptine

This study focused on the intracellular signal transduction system and microtubule-associated proteins (MAPs), such as MAP-2 and Tau protein. The modulation of these proteins and their correlation with ultrastructural changes were investigated in rat pituitary prolactin (PRL) cells. Adult female Wistar rats were treated with estrogen and bromocriptine and their pituitary glands were removed for analysis of the expression of tubulin, MAP-2, Tau protein, protein kinase C (PKC), and calcium calmodulin (CaM) kinase. Western blot analysis showed that estrogen increased and bromocriptine decreased the expression of PKC alpha, beta 1, beta 2, CaM kinase alpha, beta, MAP-2, and Tau protein. MAP-2 and Tau protein, which are cytosolic proteins, being translated on free ribosomes, were associated with the membrane of whirling rough endoplasmic reticulum (RER) in estrogen-treated cells and dissociated with vesiculated RER induced by bromocriptine. These results suggested that the modulation of MAP-2 and Tau protein may reflect changes of PKC and CaM kinase, and that the quantitative changes and intracellular modulation of MAPs induced by estrogen and bromocriptine, i.e., estrogen-induced association and bromocriptine-induced dissociation of MAP-2 and Tau protein with membrane of RER, may reflect the dynamics of microtubules and are associated with structural changes in the RER and changes in the synthesis and intracellular transport of PRL.

Prohormone convertases (PC1/3 and PC2) in rat and human pancreas and islet cell tumors: subcellular immunohistochemical analysis

Prohormone convertase 1/3 (PC1/3; also termed PC1 or PC3) and PC2 are enzymes that activate prohormones by cleaving the pairs of basic amino acids. This mechanism was initially inferred from the series of several endocrine and neuroendocrine precursor proteins, including proinsulin and proglucagon. To determine the cellular and subcellular distribution of PC1/3 and PC2 in the rat and human pancreas, immunohistochemistry was performed using polyclonal antisera against mouse PC1/3 (ST-28) and mouse PC2 (ST-29). These studies showed light and electron microscopic co-localization of insulin, PC1/3 and PC2, and the coexistence of glucagon and PC2 in the pancreatic islets. This tendency of colocalization was also depicted in one case of human insulinoma and three cases of human glucagonomas, as well as in rat insulinomas. In two cases of human insulinomas, incomplete processing of proinsulin was suggested by the absence of PC2. At the subcellular level in the rat pancreatic islet, the colocalization of PC1/3 and insulin, and that of PC2 and glucagon, were observed in the same secretory granules by immunoelectron microscopy and image analysis. These studies suggest that PC1/3 and PC2 can function with the specificities in the processing of proinsulin and proglucagon into their active forms, respectively, in the normal and neoplastic pancreatic islets.

Simultaneous ultrastructural identification of growth hormone and its messenger ribonucleic acid using combined immunohistochemistry and non-radioisotopic in situ hybridization: a technical note

The present electron microscopical study is concerned with the simultaneous visualization of messenger ribonucleic acid (mRNA) and its encoded protein in the same specimen. Pre-embedding electron microscopical in situ hybridization (EM-ISH) on rat pituitary gland tissue localized growth hormone mRNA in the polysomes of the rough endoplasmic reticulum, and subsequent postembedding immunolabelling using protein A-colloidal gold particles identified growth hormone mainly in the secretory granules. We believe that our report provides the first simultaneous ultrastructural identification of mRNA and its encoded protein using combined pre-embedding EM-ISH and immunohistochemistry. In this method, the signals for mRNA were localized specifically as highly electron dense products on the polysomes of the endoplasmic reticulum, and those for its encoded protein were recognized as gold particles both in the cisternae of the reticulum and in the secretory granules. Our ultrastructural double labelling method for mRNA and protein may provide a tool to find important clues for elucidating the intracellular correlation of mRNA translation and secretion of translated protein, because of its high resolution, good morphological preservation, and the specific localization of the reaction products.

In situ nick end-labeling detects necrosis of hippocampal pyramidal cells induced by kainic acid

It is believed that in situ nick end-labeling (ISNEL) is an easy and selective method for detecting apoptosis in situ. To test whether ISNEL selectively detects apoptosis but not necrosis, we investigated the kainic acid (KA)-induced neuronal death with ISNEL, comparing with the results of gel electrophoresis and electron microscopy. Many degenerating neurons (ca. 50%) in the hippocampal CA1 area and amygdaloid complex were intensely stained with ISNEL 1-3 days after intraperitoneal injection of KA. Although most of the ISNEL-positive neurons displayed a pathological feature of necrosis, a small number of them displayed apoptosis-like changes when examined by electron microscopic observation. It should be noteworthy that ISNEL recognizes at least a certain form of necrosis and is not selective for apoptosis.

Immunolocalization of glutathione-peroxidase (GSH-PO) in the rat ventral prostate: effects of castration and administration of testosterone

Immunolocalization of glutathione-peroxidase (GSH-PO) in the rat ventral prostate was studied in the presence and absence of androgen. Male Sprague-Dawley rats were divided into four experimental groups. Group 1 consisted of intact controls. In group 2, rats were sacrificed two days after castration. In groups 3 and 4, rats were injected subcutaneously with 1 mg of testosterone-propionate daily, for three or seven days, beginning two days after castration. The intensity of GSH-PO staining in the glandular epithelial cells of the ventral prostate decreased after castration, but recovered following treatment with testosterone. Furthermore, the prostatic GSH-PO mRNA levels were diminished in the castrated rat ventral prostate but greatly increased by testosterone. These findings strongly suggest that the expression of GSH-PO in the glandular epithelial cells of the rat ventral prostate is dependent on testosterone.

Expression of Pit-1 and estrogen receptor messenger RNA in prolactin-producing pituitary adenomas

The pituitary-specific transcriptional factor, Pit-1, is a member of the POU-domain family, which has a role in the development and differentiation of three pituitary cell types: somatotrophs, lactotrophs, and thyrotrophs. Recently, specific DNA-dependent interactions have been observed between Pit-1 and nuclear receptors, including: thyroid hormone receptor; retinoic acid receptor; glucocorticoid receptor; and estrogen receptor (ER). The cooperative interaction between Pit-1 and ER required for prolactin enhancer activity in rat pituitaries has been suggested. We analyzed the expression of Pit-1 messenger ribonucleic acid (mRNA) and ER mRNA in 15 human prolactin-producing adenomas using nonradioisotopic in situ hybridization. Their products were also studied by immunohistochemical analysis. Pit-1 mRNA was detected in 12 (80%) of 15 prolactin-producing adenomas. On the other hand, ER mRNA was detected in 14 (94%) of adenomas studied. mRNAs of Pit-1 and ER were detected more frequently than immunohistochemical expression of their products. By combined in situ hybridization and immunohistochemical examination, Pit-1 mRNA and ER mRNA were often colocalized with prolactin immunoreactivities. The colocalizations of Pit-1 mRNA and ER protein were observed in adenoma cells. The high incidence of the expression of ER mRNA in prolactin-producing adenomas may suggest cooperative interactions between Pit-1 and ER in functional differentiation and development of prolactin-producing adenomas.

In situ hybridization analysis of Pit-1 mRNA and hormonal production in human pituitary adenomas

The pituitary-specific transcriptional factor, Pit-1, is a member of the POU-domain family which has a role in the development and differentiation of three pituitary cell types: somatotrophs, lactotrophs, and thyrotrophs. Recent investigations have suggested the involvement of specific regulation of Pit-1 transcripts in human pituitary adenomas. In this study, we analyzed the expression of Pit-1 gene and Pit-1 product in various human pituitary adenomas using in situ hybridization (ISH) and immunohistochemistry (IHC). Northern hybridization analysis revealed 2.4- and 4.1-kb Pit-1 transcripts in normal pituitary, growth hormone (GH)-, prolactin (PRL)- and thyrotropin (TSH)-secreting adenomas. By ISH analysis, Pit-1 mRNA was detected in 42 (84%) of 50 adenomas. The highest incidence was observed in 15 GH-secreting adenomas and 8 TSH-secreting adenomas, in which Pit-1 mRNA was detected in all cases. Pit-1 mRNA expression was detected in 11 (85%) of 13 PRL-secreting adenomas. In 12 clinically non-functioning adenomas, Pit-1 mRNA was also present in 8 cases, and 5 of these were associated with immunohistochemical expression of Pit-1 product. By combined ISH and IHC, Pit-1 mRNA was often colocalized with GH, PRL or TSH beta immunoreactivities and sometimes colocalized with alpha-subunit of glycoprotein (alpha SU) immunoreactivity. The expression of Pit-1 mRNA in various cell types of human pituitary adenomas in addition to GH, TSH beta and PRL immunoreactivities suggests that Pit-1 may play a role in functional development of pituitary adenomas, including clinically non-functioning adenomas. However, some additional transcriptional factors or enhancers may be required.

Activation of protein kinase C by oxidized diacylglycerols

The effects of 1,2-diacylglycerol hydroperoxide (DAG-OOH), its alcohol (DAG-OH), "unoxidized" 1,2-diacylglycerol (DAG), 1,2-dioleoylglycerol (DOG), and phorbol 12-myristate acetate (PMA) on the activity of protein kinase C (PKC) isolated from rat brain were examined in the presence and absence of phosphatidylserine (PS) and calcium ion. Both DAG-OOH and DAG-OH stimulated the activity of PKC dose- and time-dependently. The ability of additives for PKC activation increased in the order of DOG, DAG << DAG-OOH, DAG-OH < PMA. DAG-OOH and DAG-OH activated PKC even in the absence of PS and calcium ion as PMA does. If DAG-OOH and DAG-OH are released from the oxidized biomembranes by the action of phospholipase C, these components may act like PMA and serve to activate the PKC-dependent signal transduction system.

GH and PRL gene expression by nonradioisotopic in situ hybridization in TSH-secreting pituitary adenomas

TSH-secreting pituitary adenomas are rare. The transcriptional expression (messenger ribonucleic acids: mRNAs) of TSH beta, GH, and PRL in five patients with TSH-secreting pituitary adenoma was studied by the in situ hybridization (ISH) method in order to elucidate their multiple hormone production. These patients showed inappropriately elevated serum TSH and alpha-subunit levels as well as pituitary mass lesions. The tissues from pituitary adenomas were obtained at the time of transsphenoidal surgery and revealed immunohistochemically the expression of alpha-subunit and TSH beta in all patients. Four adenomas were immunohistochemically associated with GH or PRL localization. The presence of pituitary-specific transcriptional factor Pit-1 was demonstrated in all adenomas in the nuclei of many cells. By ISH, signals for TSH beta mRNA were present in all five cases in many adenoma cells. Expression of GH mRNA and PRL mRNA were detected not only in four adenomas in which both hormonal products were immunolocalized but also in one adenoma that was immunohistochemically negative for GH and PRL. Combined staining by ISH and immunohistochemistry revealed the expression of GH mRNA and PRL mRNA in TSH beta-immunoreactive cells. Our findings indicate that TSH-secreting adenomas are multihormone-producing and could arise from precursor or stem cells rather than from differentiated TSH-secreting cells. It is suggested that ISH combined with immunohistochemistry may provide additional detailed information concerning the multidirectional histogenesis of this rare type of adenoma.

Changes in the ultrastructural distribution of prolactin and growth hormone mRNAs in pituitary cells of female rats after estrogen and bromocriptine treatment, studied using in situ hybridization with biotinylated oligonucleotide probes

The expression and distribution of prolactin (PRL) mRNA and their alterations induced by estrogen and bromocriptine were investigated using non-radioisotopic in situ hybridization (ISH) at the electron microscopic (EM) level. Our EM-ISH studies using biotinylated oligonucleotide probes showed that estrogen induced whirling changes of the rough endoplasmic reticulum (RER) of female rat PRL cells and increased transcription of PRL genes located on the polysomes of the whirling RER. The presence of mammosomatotroph cells in the rat pituitary gland was also verified in our EM-ISH studies. After bromocriptine administration, PRL cells contained many secretory granules due to the inhibition of secretion. Pre- and post-embedding EM-ISH and northern hybridization studies revealed that bromocriptine induced the distorted, vesiculated, and dilated RER, and also the suppressed PRL mRNA expression. The activity of protein kinase C (PKC), which mediates PRL gene expression, tended to be elevated by estrogen and suppressed by bromocriptine. Therefore, it is considered that the ultrastructural and quantitative changes in PRL mRNA expression evoked by estrogen and bromocriptine may be mediated by the intracellular signal transduction system, including PKC.

Expression of plurihormonal mRNAs in somatotrophic adenomas detected using a nonisotopic in situ hybridization method: comparison with lactotrophic adenomas

We used a nonisotopic in situ hybridization (ISH) method to investigate the expression of pituitary hormone, including glycoprotein hormone mRNAs in 17 somatotrophic and four lactotrophic adenomas. Our ISH studies of lactotrophic adenomas showed that their hormonal gene expression was confined to prolactin, whereas those of somatotrophic adenomas showed that some of them expressed plurihormonal genes. In some somatotrophic adenomas that were immunohistochemically negative for pituitary hormones, positive reactions, mainly for adrenocorticotropic hormone (ACTH), follicle-stimulating hormone beta subunit (FSH beta), and luteinizing hormone beta subunit (LH beta) mRNAs, were observed in our ISH studies. These results suggest that some somatotrophic adenomas may originate from plurihormonal primordial stem cells, which we have presumed serve as precursors for various hormone-expressing cells. It is unclear why some somatotrophic adenomas derived from plurihormonal primordial stem cells manifest clinically only as the acromegalic hyperfunction syndrome or gigantism. Additional translational factors or some other somatic mutations may play important roles in the clinical manifestations of such adenomas. In conclusion, some somatotrophic adenomas appear to be derived from plurihormonal primordial stem cells, whereas lactotrophic adenomas are well differentiated tumors that originate from lactotrophic cells, which represent the final stage of acidophilic cell line differentiation.

Ultrastructural distribution of growth hormone and prolactin mRNAs in normal rat pituitary cells: a comparison between preembedding and postembedding methods

In situ hybridization (ISH) at the electron microscopic level is essential for elucidating the intracellular distribution and role of mRNA in protein synthesis. We describe our electron microscopic ISH method using biotinylated oligonucleotide probes for rat growth hormone and prolactin mRNAs and compare the preembedding method with the postembedding method. Preembedding electron microscopic ISH localized rat growth hormone and prolactin mRNAs on the polysomes of the rough endoplasmic reticulum (RER). Rat growth hormone mRNA was distributed diffusely on the RER, whereas rat prolactin mRNA was scattered and distributed focally. Thus there might be a specific translational site for prolactin mRNA on the RER. Rat growth hormone mRNA signals were also recognized on the polysomes of the RER, using the postembedding method with streptavidin gold conjugate. The hybridization signal intensity using the postembedding method was lower, and non-specific signals were more frequent, in comparison with the preembedding method. The preembedding method thus appears to be easier and better than the postembedding method from the viewpoint of utility and preservation of mRNA. Electron microscopic ISH is considered to be an important tool for evaluating the intracellular localization of mRNA and the site of specific hormone synthesis on the RER.

Application of biotinylated oligonucleotide probes to the detection of pituitary hormone mRNA using northern blot analysis, in situ hybridization at the light- and electron-microscope levels

There have been many reports on radioisotopic in situ hybridization (ISH) studies for the demonstration of pituitary hormone mRNAs in normal pituitary gland and pituitary adenomas. Recent studies have revealed that non-radioisotopic ISH has several advantages over the radioisotopic method. Using ISH with biotinylated oligonucleotide probes, we have been able to localize various pituitary hormone mRNAs in paraffin wax or frozen sections of rat normal pituitary gland and human pituitary adenomas. For control studies we used ISH with sense probes, ISH without probes, pretreatment with ribonuclease, ISH with a probe for beta-actin and Northern blot hybridization. Using biotinylated probes, gene transcripts of rat growth hormone and prolactin were detected by Northern blot hybridization. The same biotinylated probes were used not for light microscope ISH but also for the electron microscopical demonstration of rat growth hormone and prolactin mRNAs on the polysomes of the rough endoplasmic reticula. It is emphasized that biotinylated oligonucleotide probes are useful for the analysis of pituitary endocrine function because they are applicable to the three hybridization methods, namely, Northern blot hybridization and ISH at the light and electron microscope levels.

Effects of ipriflavone on calcitonin synthesis in C cells of the rat thyroid

Ipriflavone is known to stimulate calcitonin (CT) secretion from the thyroid glands of female animals, but the exact mechanism of this action remains unknown. In the present study, an increase of CT production in thyroid C cells of female rats, but not of male rats, was proven immunohistochemically. Furthermore, the parallel increase of CT mRNA in those thyroid glands was confirmed by Northern blot analysis. These results proved that ipriflavone stimulates not only CT secretion but also CT synthesis in thyroid C cells and that the changes were gender dependent (greater in females). In order to investigate the effect of estrogen on the ipriflavone-induced increase of CT in female rat thyroid gland, CT and CT mRNA in the thyroid glands of untreated, ovariectomized, and estrone-treated (postovariectomy) rats were examined by both immunohistochemistry and Northern blot technique. Serum levels of CT and calcium were also examined. Against expectation, estrone failed to produce any significant effect on the ability of ipriflavone to induce CT synthesis and secretion.

Biochemical and immunohistochemical analysis of orotic acid-induced fatty liver

Orotic acid-induced fatty livers were examined by biochemical and immunohistochemical approaches. Lipid peroxide levels by the thiobarbituric acid method and glutathione-peroxidase (GSH-PO) activity in the liver homogenates from orotic administered rats were similar to those of controls. Immunohistochemical localization of GSH-PO in orotic acid-induced fatty liver was mainly observed in the portal zone of the hepatic lobules. This staining pattern of GSH-PO was similar to that of the controls. No remarkable changes in GSH-PO staining patterns were detected in orotic acid-induced fatty liver. Our data strongly suggested that no lipid peroxidation is actively involved in the genesis of fatty liver due to the administration of orotic acid, and GSH-PO a protective enzyme against lipid peroxidation, was not inhibited by orotic acid-induced fatty liver.

Electron microscopic identification of the intracellular secretion pathway of human G-CSF in a human tumor cell line: a comparative study with a Chinese hamster ovary cell line (IA1-7) transfected with human G-CSF cDNA

Using monoclonal antibodies specific for human granulocyte colony-stimulating factor (G-CSF), intracellular localization of G-CSF in a G-CSF-producing human tumor cell line (CHU-2) and its ultrastructural characters were described and compared with those of a Chinese hamster ovary cell line (IA1-7) transfected with human G-CSF cDNA. The CHU-2 line, which was derived from a poorly differentiated squamous cell carcinoma of the oral cavity, preserved the character of a poorly differentiated squamous cell carcinoma. In the CHU-2 cell line, there were few cells immunohistochemically positive for G-CSF under light microscopic analysis despite the high transcription level of G-CSF cDNA and secretion of G-CSF that were comparable with cDNA-transfected IA1-7 cells. Using electron microscopy, the reaction products were localized mainly in the perinuclear space (PNS) and rough endoplasmic reticula (RER) without dilation of the cisternae, but they were very rarely found in the Golgi complex and not at all in other intracellular organelles. In contrast, most cells were positive for G-CSF in the IA1-7 cell line. Reaction products in this cell line were also demonstrated in the PNS and RER without dilation of the cisternae. These immunohistochemical findings, in conjunction with the results of Western and Northern blot analysis, suggested that G-CSF was secreted via the PNS and RER without intracellular retention.

Different effects of carbon tetrachloride on carcinogen-induced hepatocellular carcinoma and normal liver of the rat: lowered lipid peroxidation and accelerated necrosis in cancer

To investigate molecular responses to lipid peroxidative stimuli in neoplastic cells, lipid peroxidation was induced in liver of rats bearing 3'-methyl-4-dimethylaminoazobenzene-induced hepatocellular carcinoma by injecting a high dose of carbon tetrachloride (CCl4), a strong lipoperoxidative reagent. Normal rat livers with or without CCl4 treatment served as controls. CCl4 administration markedly provoked fatty metamorphosis, visualized by oil red O staining, in normal livers while minimal fatty changes were seen in hepatocellular carcinomas, where necrosis was often observed instead. After CCl4 treatment, the thiobarbituric acid values (representing levels of lipid peroxides in the tissue) were increased two-fold in the untreated normal liver, but were unchanged in the cancer tissue. Levels of vitamin C, an acutely reactive antioxidant, measured by high-performance liquid chromatography were not influenced by the CCl4 injection in the cancer tissue whereas a significant decrease was evident in normal livers. The total fatty acid content, measured by gas chromatography, was significantly lower in the cancer tissue than in the normal liver while the ratio of polyunsaturated fatty acids (PUFAs) in total fatty acids was little changed. Resistance of hepatocellular cancer cells to fatty metamorphosis and their susceptibility to necrosis induced by free radicals may be due to the paucity of the target PUFAs in their cell membrane fraction, resulting in low levels of lipid peroxides. Peroxidation of PUFAs might act as a "shock absorber" against free radical-induced toxic cell death in normal cells.

Effects of synthetic salmon calcitonin on C cells of the thyroid

The effects of long-term administration of synthetic salmon calcitonin (TZ-CT) on thyroid C cells of rats were evaluated immunohistochemically and electron microscopically. Low dose (0.075, 0.75 and 7.5 IU/kg/day) administration caused no significant changes in the C cell population, whereas high doses (30 and 120 IU/kg/day) caused C cell suppression. The area ratio of C cells to total cells in the thyroid was measured on sections immunoperoxidase stained for calcitonin. The average C cell ratio was compared among the experimental groups. This morphometric analysis of the high-dose and control groups confirmed the differences in C cell populations statistically (30 IU/kg vs. control, p less than or equal to 0.05; 120 IU/kg vs. control, p less than or equal to 0.05). The suppressive effect of TZ-CT on C cells was reversible after cessation of administration for one month. Electron microscopic examination on the C cells in the high-dose groups revealed no particular ultrastructural differences. These results may suggest a negative feedback mechanism on C cells by exogenous CT.

Determination of nucleotide sequence of cDNA coding rat glutathione peroxidase and diminished expression of the mRNA in selenium deficient rat liver

The cDNA for rat glutathione peroxidase mRNA was isolated from liver cDNA library in lambda gt11 by cross-hybridization using the mouse cDNA, and it's nucleotide sequence was determined. The selenocysteine which constitutes an active center of this enzyme was encoded by TGA, a nonsense codon in general, as was the cases with mouse and human glutathione peroxidase. Northern blot analysis elucidated that the mRNA for glutathione peroxidase was markedly diminished in selenium deficient rat liver as compared with that of normal rat livers. The result suggested that the de novo synthesis of the mRNA would be regulated by selenium.

Novel and potent biological antioxidants on membrane phospholipid peroxidation: 2-hydroxy estrone and 2-hydroxy estradiol

Catechol estrogens, 2-hydroxy estrone, 2-hydroxy estradiol and 2-hydroxy estriol, were tested as possible antioxidants of phospholipid peroxidation induced by Fe3+-ADP-adriamycin, using phospholipid liposomes as lipid source and alpha-tocopherol or other steroids as reference compounds. The parameters of antioxidant activities were: elongation of induction period, inhibition of O2 consumption required for lipid peroxidation and inhibition of peroxidative cleavage of unsaturated phospholipid. Of the tested compounds, 2-hydroxy estradiol or 2-hydroxy estrone had more potent activity than that of tocopherol.