Biomedical subjects

R Y Osamura

Publications and source records attributed to R Y Osamura.

At least 91 records · Page 5Linked to original sources

PubMed1997

Gonadotropin-releasing hormone and gonadotropin-releasing hormone receptor messenger ribonucleic acids expression in nontumorous and neoplastic pituitaries.

In the nontumorous pituitary, GnRH stimulates the release and synthesis of LH and FSH by gonadotroph cells via the GnRH receptor (GnRH-R). Little is known, however, about expression of GnRH and GnRH-R messenger RNAs (mRNAs) in nontumorous pituitary tissue and in adenomas. To learn more about the distribution and regulatory roles of GnRH and its receptor, we investigated the expression of both GnRH and GnRH-R mRNAs in nontumorous human pituitary and in various types of pituitary adenomas using the RT-PCR, in situ hybridization, and in situ hybridization in combination with RT-PCR (in situ RT-PCR). Using RT-PCR, GnRH mRNA was found to be expressed in normal human pituitaries and in all types of adenomas. Similarly, GnRH-R mRNA was expressed in nontumorous human pituitaries and in most, but not all, adenomas. These included 5 gonadotroph adenomas, 6 null cell adenomas, 1 of 2 GH-producing tumors, and 1 of 2 ACTH-producing adenomas, but not in the 2 PRL-producing adenomas examined. In situ hybridization studies showed GnRH and GnRH-R mRNAs in all 3 nontumorous pituitaries and in 12 of 33 (36.4%) and 10 of 33 adenomas (30.3%), respectively. Using an indirect in situ RT-PCR technique to increase the sensitivity of the in situ localization, GnRH and GnRH-R mRNAs were detected in 29 (87.9%) and 25 (75.8%) of 33 adenomas, respectively. This is the first report of the localization of GnRH and GnRH-R mRNAs in individual pituitary adenoma cells using in situ RT-PCR. The frequent expression of GnRH and GnRH-R mRNAs in pituitary cells suggests that GnRH has autocrine/paracrine functions in nontumorous and neoplastic pituitary tissues.

Gonadotropin-Releasing Hormone↗

PubMed1997

A growth hormone-releasing hormone-producing pancreatic islet cell tumor metastasized to the pituitary is associated with pituitary somatotroph hyperplasia and acromegaly.

The functional and morphological changes in the pituitary gland caused by a GHRH-producing pancreatic islet cell tumor that metastasized to the pituitary and caused somatotroph hyperplasia are described. A 52-yr-old woman presented with loss of visual acuity, diabetes insipidus, and acromegaly caused by a GHRH-producing endocrine carcinoma metastasized to the pituitary. The serum GHRH, GH, and insulin-like growth factor I levels of the patient were elevated. Immunohistochemical and in situ hybridization study revealed GHRH immunoreactivity and GHRH messenger RNA (mRNA) in the metastatic tumor cells. The anterior pituitary showed hyperplasia of somatotroph cells with intact acinar structure that did not contain an adenoma, determined by light microscopy using silver impregnation. Electron microscopy revealed hyperplastic characteristics of densely granulated somatotrophs. In situ hybridization documented strong signals for GH mRNA and pituitary-specific transcriptional factor Pit-1 mRNA in the hyperplastic somatotrophs. A weak signal for GHRH receptor mRNA was detected in these somatotrophs. However, using in situ RT-PCR, GHRH receptor mRNA was more conclusively observed in most of the somatotrophs. The excessive production of GHRH by metastatic tumor may have resulted in somatotroph hyperplasia by the synergistic effects of Pit-1 and GHRH receptor. It can be concluded that the pathogenesis of pituitary adenoma formation is primarily mediated by other factors than hypothalamic hormone.

Acromegaly↗

PubMed1997

Immunoelectron microscopic demonstration of regulated pathway for calcitonin and constitutive pathway for carcinoembryonic antigen in the same cells of human medullary carcinomas of thyroid glands.

The human medullary carcinomas are well known to secrete calcitonin (CT) as a neuroendocrine peptide and carcinoembryonic antigen (CEA) as a serum protein that is integrated into the cell membrane. This ultrastructural study is designed to elucidate whether CT and CEA are secreted via two different intracellular secretory pathways, a regulated pathway and a constitutive pathway. The immunoelectron microscopic postembedding method, performed on four cases of the human medullary carcinomas of the thyroid using plastic embedding material, disclosed two distinct different localization patterns for CT and CEA. CT was localized exclusively in dense cored secretory granules. CEA was present in the cell membrane and in the secretory vesicles. The secretory granules were completely negative for CEA. The trans-Golgi networks were also positive for CT and CEA. Electron microscopic double staining confirmed these localization in the same carcinoma cells. These observations suggest the presence of two distinct pathways in the endocrine cancer cells, i.e., the regulated pathway for CT and the constitutive pathway for CEA.

Biological Transport↗

PubMed1997

A study of 46 cumulative breast cancer autopsy cases.

Forty-six cases of breast cancer, autopsied at the Tokai University Hospital, between 1975 and 1993, were studied. Forty of the patients had undergone surgery, and 27 of them had been surgically treated in the Tokai University Hospital. The major causes of death were respiratory failure, cancer-related complications, and hepatic failure. Frequently involved organs were lymph node, lung, liver, and bone. The survival time after surgery ranged from 1 day to 137 months, with the patients being divided into two groups based on survival of more or less than three years after surgery. Frequently observed in individuals surviving less than 3 years were larger tumor sizes, extensive lymph node metastases, advanced stages, and negative reactions for estrogen and progesterone receptors, as compared to individuals surviving for more than 3 years. The patterns of tumor metastasis were also different in two groups. Local recurrences were more frequently observed in short-term survivors whereas disseminated spreading was encountered in the long-term survivors. These findings seem to indicate that not only survival time but also pattern of recurrence are related to the status of the original tumor.

Autopsy↗

PubMed1997

A case of epithelioid hemangioendothelioma associated with an artery.

We report a case of epithelioid hemangioendothelioma (EHE) arising in the left elbow of a 67-year-old woman. The tumor was characterized by centrifugal growth and association with the brachial artery, causing complete occlusion. Immunohestochemical and electron microscopical features were typical of EHE. The patient was free of local recurrence or disease metastasis for more than 3 years after tumor resection, but subsequently died of respiratory failure due to a primary lung cancer.

Aged↗

PubMed1996

Attempt to obtain greater dermal depth of vascular injury using dye-enhanced laser technique: a new approach.

BACKGROUND AND OBJECTIVE: Although pulsed dye laser has been successfully used in the treatment of portwine stains, a number of patients had incomplete clearance because the depth of penetration by the pulsed dye laser was inadequate. This study was performed to establish the greater penetration depth of vascular injury using a dye-enhanced laser technique. STUDY DESIGN/MATERIALS AND METHODS: The ruby laser at 694.3 nm was used, and the corresponding specific dye was Prussian blue solution (maximum absorbance 694 nm). We compared the penetration depth of vascular injury by the ruby laser irradiation after the Prussian blue injection with that by the dye laser irradiation. A flashlamp dye laser with a pulse duration of 300 microseconds and a 5 mm diameter spot size was used to 6.2 J/cm2 at 590 nm. The Prussian blue solution was injected into the superficial epigastric artery of white male Japanese rabbits, immediately followed by the ruby laser exposure to 6.2 J/cm2 at a pulse duration of 283 microseconds in a 15 x 15 mm spotsize. Depth of penetration was measured from the dermoepidermal junction to the deepest site of vascular injury at 24 hours after laser exposure. RESULTS: Mean penetration of 590 nm of the dye laser light was 1.45 mm; mean penetration of the 694.3 nm ruby laser irradiation after the Prussian blue injection was 2.33 mm. Ruby laser penetration was greater than that of the dye laser. CONCLUSION: This study emphasizes that the ruby laser irradiation after the Prussian blue injection can induce deeper vascular injury than the dye laser inducing similar pathological changes.

Animals↗

PubMed1996

Clinical and cytofunctional classification of pituitary adenomas: proposal of a new classification.

Recent methodological advances in immunohistochemistry, ultrastructural techniques, hormonal assays, resolution imaging and molecular biology techniques have provided new insights into the pathology, function and cytogenesis of pituitary adenomas. Pituitary adenomas have been classified historically on the basis of tinctorial affinities, followed by the basis of ultrastructure and immunohistochemistry. The current development of technologies necessitate the new classification of pituitary adenomas which integrates these numerous parameters as well as the clinical manifestations. For this purpose, we suggest a new clinico-cytofunctional classification of pituitary adenomas, which is based on these clinical manifestations and integrates the information on biology, imaging function and ultrastructure. This classification which corresponds to current advances will not only provide pertinent clinical data but facilitate better understanding of the biology and nature of these complexed lesions.

Adenoma↗

PubMed1996

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.

Animals↗

PubMed1996

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.

Adenoma↗

PubMed1996

Application of catalyzed signal amplification in immunodetection of gonadotropin subunits in clinically nonfunctioning pituitary adenomas.

Pituitary adenomas that are characterized by the absence of a particular clinical syndrome and the absence of excessive hormone secretion have been classified as nonfunctioning adenomas. Recent development of immunohistochemical analysis and hormonal assay have suggested that many of these tumors have function to secret the gonadotropin subunits. A novel procedure biotin amplification in immunohistochemistry, catalyzed signal amplification (CSA) has been reported recently. In this study, the authors applied this new method to tissues from 50 cases of clinically nonfunctioning adenomas. These cases had no evidence of endocrinological signs by hormone secretion. When the CSA system was applied in normal pituitary gland, each of subunits was positive even when the antibody was diluted 1:1,000,000, which is 1,000 folds of standard indirect immunoperoxidase method. Immunohistochemical staining by indirect immunohistochemical method revealed that all 50 adenomas were negative for all the anterior hormones, including growth hormone (GH), prolactin (PRL), adrenocorticotropic hormone (ACTH), beta-subunit of luteinizing hormone (LH beta), follicle-stimulating hormone (FSH beta), thyroid stimulating hormone (TSH beta), and a-subunit of glycoprotein (alpha SU). Using avidin-biotin complex (ABC) method, two cases were positive for FSH beta and four cases were positive for alpha SU, respectively, and the immunopositivities were observed weakly in scattered cells. By CSA system, 26 cases of 50 nonfunctioning adenoma were positive for FSH beta, 16 cases were positive for LH beta, and 29 cases were positive for alpha SU, respectively. The immunoreactivities were clearly observed in cytoplasm of many adenoma cells. This amplification procedure provides a means of greatly increasing the sensitivity of the immunohistochemistry including subunits of glycoproteins that are difficult to detect by previous indirect immunoperoxidase method or ABC method. This amplification procedure provides a great increase in the sensitivity of the immunohistochemistry for the detection of gonadotropin subunits and suggest that significant proportion of the nonfunctioning adenomas are gonadotropin subunit producing adenomas.

Adenoma↗

PubMed1996

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.

Adenoma, Islet Cell↗

PubMed1996

Cell renewal and functional morphology of human lactating breast: presentation of a new mode of cell death ('magentosis') characterized by nuclear periodic acid-Schiff reactivity.

Cell kinetics and functional morphology of the human lactating breast were analyzed using 21 paraffin-embedded specimens of the lactating breast obtained by biopsy or surgery and two of the 'resting' breast. Four types (I-IV) of lactating lobules were categorized histologically, and were well correlated with their functional status demonstrated by immunohistochemistry for epithelial membrane antigen, beta-casein, lipase, lactoferrin, secretory component and IgA. Type I corresponded to a pre-lactating state, type II to an actively lactating state, type III to an early stage of regression, and type IV to an advanced stage of regression. Cell proliferation monitored by Ki-67 (MIB-1) immunostaining was at the highest level in type I lobules followed by type IV, while the labeling indices were low in types II and III. Apoptosis demonstrated by terminal deoxynucleotidyl transferase (TdT)-mediated deoxyuridine triphosphate (dUTP)-biotin nick end-labeling (TUNEL) method showed labeling profiles comparable with the proliferative activity. Holocrine-type desquamative cells with intact-appearing nuclei were frequently recognized in type II lobules. In type III, a peculiar form of cell death, designated 'magentosis', was demonstrated. These degenerative cells occasionally shedding into the acinar lumen possessed homogeneous pale, TUNEL-negative nuclei with diastase-resistant periodic acid-Schiff (PAS) reactivity. 'Magentosis' specifically identified in an early phase of involution of the human lactating breast might represent a unique mode of cell death distinguishable from apoptosis and necrosis.

Adult↗

PubMed1996

'Magentosis' in human lactating breast: a mode of cell death accumulating single-stranded DNA stretches or breaks.

Pale and homogeneous-looking nuclei of degenerative acinar cells selectively seen in an early regression stage of the human lactating breast were periodic acid-Schiff (PAS)-reactive. In our preceding paper, this peculiar morphologic feature was designated as 'magentosis'. The present paper was aimed at histochemically clarifying the nature of the 'magentotic' nuclei. The diffuse PAS reactivity was not influenced by pretreatments with alpha-amylase, DNase, RNase, proteinase K, nor by hydrochloric acid or heating. The nuclei were negative for acid mucosubstances and secretory glycoproteins, and were unreactive with a variety of lectins. In contrast, the presence of single-stranded DNA stretches or breaks was proven. The 'magentotic' nuclei in non-heated paraffin sections were hybridized with a heat-denatured DNA probe for human DNA consensus sequences and were focally immunoreactive with an antibody to single-stranded DNA. The terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) method turned to be positive after digestion by mung bean nuclease, a single-stranded DNA-specific enzyme. The 'magentotic' nuclei were further clearly labeled by the in situ nick translation method. The nucleoli were devoid of reactivity for both the PAS and single-stranded DNA signals. We propose that 'magentosis' represents a unique mode of cell death, distinct from apoptosis and necrosis or oncosis. The PAS reactivity in the 'magentotic' nuclei may be correlated with the occurrence of single-stranded stretches or breaks in the DNA chain.

Adult↗

PubMed1996

Intermediate lymphocytic lymphoma massively involving the gastrointestinal tract.

A case is presented of intermediate lymphocytic lymphoma seen in a 53 year old male, which extensively infiltrated systemic organs, including the entire digestive tract from the esophagus to the rectum. Peyer's patch invasion was evident. Multiple intestinal perforations caused death 5 months later. Surface marker studies suggested the marginal zone origin for this CD20+ B cell malignancy.

Antigens, CD↗

PubMed1996

Combined non-isotopic in situ hybridisation and indirect immunohistochemical analysis of hormone production in the rat pituitary gland.

An understanding of the intracellular relation between hormonal expression (storage) and gene expression (production) is essential for elucidating the functional status of the individual cells in endocrine tissue such as the pituitary gland. To this end, mRNA expression was visualised by using a combined in situ hybridisation and immunohistochemistry method in routinely processed, formalin fixed, paraffin wax embedded rat pituitaries. mRNA was detected by non-isotopic in situ hybridisation (alkaline phosphatase antialkaline phosphatase method, with nitroblue tetrazolium and 5-bromo-4-chloro-3-indolylphosphate as substrates). Sections were then stained by using the immunoperoxidase method to demonstrate pituitary hormone expression. The specificity of the combined staining method was confirmed by staining adjacent sections separately. The antigenicity of rat growth hormone and prolactin was adequately preserved following hybridisation. In conclusion, this method is specific, easy to use and permits the determination of the functional status of individual cells.

Journal Article↗

PubMed1996

Enhancement of TdT-mediated dUTP-biotin nick end-labeling (TUNEL) method using mung bean nuclease, a single-stranded DNA digestion enzyme.

The TdT-mediated dUTP-biotin nick end-labeling (TUNEL) method has been employed widely to demonstrate apoptotic cells in routinely prepared paraffin sections. Because the apoptotic cells were reactive with the antibody to single-stranded DNA, we attempted to enhance the TUNEL positivity by pretreatment with single-stranded DNA digestion enzymes, S1 nuclease, and mung bean nuclease. When mung bean nuclease (5 U/50 microliter/section) was incubated at 37 degrees C for 30 min, the TUNEL reaction was most effectively enhanced. Pretreatment with S1 nuclease (0.25 U/50 microliter/section) at 37 degrees C for 45 min was less reliable. Compared with the conventional TUNEL sequence, the enhancement technique using mung bean nuclease enabled us to detect more apoptotic cells in human small intestine, colon, tonsil, thymus, endometrium, ovary, liver, kidney, and pancreas. The positivity was not affected by autolytic change. The mechanism of enhancement is discussed.

Apoptosis↗

PubMed1996

Expression of human Pit-1 product in the human pituitary and pituitary adenomas. Immunohistochemical studies using an antibody against synthetic human Pit-1 product.

OBJECTIVE: Pit-1, a member of a family of the POU-domain DNA binding factors, has been known as a pituitary-specific transcriptional factor that regulates functional differentiation toward somatotrophs, lactotrophs, and thyrotrophs in the rodent pituitary gland. The aim of this study is to elucidate the role of human Pit-1 (hPit-1) protein in the differentiation of human pituitary adenomas, using immunohistochemistry. DESIGN: Anti-human Pit-1 polyclonal antibody against synthetic peptide was applied to perform the avidin-biotinperoxidase complex method on paraffin sections of 75 surgically obtained pituitary adenomas and 12 nontumorous human pituitaries obtained at autopsy. RESULTS: In normal human pituitary glands, many cells were positive for hPit-1 product in the nuclei of somatotrophs, lactotrophs, and somatomammotrophs. Among 75 pituitary adenomas, hPit-1 product was expressed in 55 adenomas (73.3%). All (100%) of the growth hormone-positive and thyrotroph cell adenomas were positive for hPit-1 product. Unexpectedly, expression of hPit-1 was found in a limited number of adrenocorticotropic hormone-producing adenomas and clinically nonfunctioning adenomas, including gonadotroph cell adenomas, although localization was found only in occasional cells. CONCLUSIONS: The invariable expression of hPit-1 protein in growth hormone-positive adenomas and thyroid-stimulating hormone-positive adenomas may suggest the role of Pit-1 protein in specific differentiation of the adenoma cells. The expression of hPit-1 in various other types of adenomas may indicate the involvement of other unidentified transcription factors or specific mediators that have roles in these differentiations. Our observation may provide some insight into the origin of cell types of some clinically nonfunctional adenomas.

Adenoma↗

PubMed1996

[Interphase cytogenetics of the breast tumors with fluorescence in situ hybridization (FISH) on cytologic preparation--its practice and clinical applications].

Fluorescence in situ hybridization (FISH) study with the chromosome specific probes is performed in the interphase nuclei of the routinely processed cytologic preparation of the breast tumors. Numerical aberrations on the chromosomes 1, 3, 11 or 17 were detected in more than 80% of the malignant tumors, but not in the benign tumors. Marked heterogeneity of the polysomies is noted in the malignant tumor cells. A few malignant cases revealed monosomy of chromosome 17. No apparent correlation between the numerical abnormalities and the histological features in malignant tumors is identified. These results suggest that the interphase cytogenetics with FISH for the breast tumors may be useful for differential diagnosis of malignancy. The practice and the clinical applications of the FISH study are discussed.

Biopsy, Needle↗