Biomedical subjects

S Iseki

Publications and source records attributed to S Iseki.

At least 55 records · Page 3Linked to original sources

PubMed1995

Immunohistochemical localization of two types of fatty acid-binding proteins in rat ovaries during postnatal development and in immature rat ovaries treated with gonadotropins.

BACKGROUND: The ovary of adult rats expresses two types of cytoplasmic fatty acid binding proteins (FABP), i.e., heart FABP (H-FABP) and intestinal 15 kDa protein (I-15P). We studied immunohistochemically the cellular localizations of these FABPs in the ovaries of rats at various postnatal ages and in the ovaries of immature (3-week-old) rats treated with pregnant mare serum gonadotropin (PMSG) and human chorionic gonadotropin (HCG). METHODS: The cryosections of ovaries were incubated with polyclonal antibodies against H-FABP and I-15P, and the immunoreactions were visualized at both light and electron microscopic levels. RESULTS: The immunoreactivity for H-FABP occurred temporarily in the follicular epithelial (granulosa) cells from 3 days to 2 weeks post partum, and then was localized exclusively to the theca/interstitial gland cells from 2 weeks to adulthood. In contrast, the immunoreactivity for I-15P appeared temporarily in a small subset of theca/interstitial gland cells from 2 to 3 weeks, disappeared at 4 weeks, and was localized exclusively to the corpus luteum cells after the onset of ovulation in the animal around 5 weeks. In the immature rat ovaries induced to ovulate by treatment with gonadotropins, I-15P-immunoreactive cells were first recognized in the luteinized granulosa layer of large preovulatory follicles, and increased in number progressively in the developing corpora lutea after the ovulation. CONCLUSIONS: Two types of FABPs are expressed in distinct steroid-producing cell types of rat ovary, and their expressions seem to be regulated in coincidence with the expressions of respective steroid hormones. These results suggest that FABPs play specific roles in the ovarian hormone synthesis.

Aging↗

PubMed1995

Expression and localization of mRNA encoding 16 kD subunit of vacuolar H(+)-ATPase in rat brain.

The 16 kD subunit of vacuolar H(+)-ATPase (V-ATPase) is essential for pumping protons into intracellular organella. Northern blot analysis revealed that the 16 kD subunit of V-ATPase is abundantly expressed in rat brain, and that the amount of transcripts is higher in the postnatal 15 days than in the adult age. On in situ hybridization, the mRNA signal for 16 kD subunit of V-ATPase was detected widely over the brain tissues of both adult and postnatal rats, with higher intensity in most of the gray matters located in the cerebellar cortex, hippocampus, thalamic nuclei, pontin nuclei, and olfactory bulb. In contrast, the signal in the cerebral cortex was preferentially enriched in the surface layers in the postnatal 10 days but was distributed diffusely and weakly over the entire layers thereafter. In all regions of brain, the mRNA signal was located predominantly in the neurons rather than in the glial components.

Animals↗

PubMed1995

Localization of transforming growth factor-beta type I and type II receptors in mouse development.

We have investigated the localization pattern of the transforming growth factor-beta (TGF-beta) receptors type I (T beta R-I) and type II (T beta R-II) during mouse organogenesis by immunohistochemical analysis. Staining of both receptors was found in many developing organs, e.g., bone, teeth, Meckel's cartilage, and neural tissues, where the expression of their ligands has been previously reported. During the investigated stages, expression of T beta R-I was more ubiquitous than that of T beta R-II. T beta R-II preferentially localized in the undifferentiated mesenchymal cells which subsequently differentiated into bone. There was no staining of T beta R-II in the central nervous system, while intense T beta R-I staining was found specifically in nervous tissues. Expression of T beta R-I and T beta R-II was mostly coincident with that of their ligands, suggesting that TGF-beta s act as multiple mediators during organogenesis. In addition, colocalization of both receptors in the epithelia of the tooth bud and submandibular gland, which were actively invaginating into the mesenchyme, leads us to speculate that both receptors may be necessary for dynamic epithelial morphogenesis.

Activin Receptors, Type I↗

PubMed1995

Immunocytochemical localization of cyclooxygenase-1 and cyclooxygenase-2 in the rat stomach.

Prostaglandins are considered to play important roles in gastric mucosal protection. The rate-limiting enzyme involved in the biosynthesis of prostaglandins is cyclooxygenase (COX), also known as prostaglandin H synthase. Two forms of COX are known: a constitutively expressed form (COX-1) and a newly-characterized, inducible form (COX-2). In the present study, the immunocytochemical localization of COX-1 and COX-2 was examined in the rat gastrointestinal tract. A strong immunoreactivity for COX-1 was localized in the mucous neck cells of gastric gland. A weak reactivity for COX-1 was also found in the mucous cell types in the cardiac gland and pyloric gland of the stomach as well as in the Brunner's gland of duodenum. Ultrastructurally, the immunoreactivity was localized to the apical cytoplasm of these cells. On the other hand, immunoreactivity for COX-2 was distributed in the surface mucous cells in both the fundic and pyloric regions of stomach. These results suggest that a subset of mucous cells is the primary site for production of prostaglandins in the rat gastrointestinal tract, and that two forms of COX are expressed in distinct types of mucous cell.

Animals↗

PubMed1995

Expression of basic fibroblast growth factor and its receptor in human pancreatic carcinomas.

We examined the expression of basic fibroblast growth factor (FGF) and FGF receptor by immunohistochemistry in 32 human pancreatic ductal adenocarcinomas. Mild to marked basic FGF immunoreactivity was noted in 19 (59.4%) of the 32 tumours examined, and 30 (93.3%) of the tumours exhibited a cytoplasmic staining pattern against FGF receptor. The tumours were divided into two groups according to the proportion of positively stained tumour cells: a low expression group (positive cells < 25%) and a high expression group (positive cells > or = 25%). No statistically significant difference in tumour size, differentiation, metastases or stage was found between the low and high basic FGF expression groups. However, a significant correlation was found between FGF receptor expression level and the presence of retroperitoneal invasion, lymph node metastasis, and tumour stage. In addition, low FGF receptor expression was significantly associated with a longer post-operative survival as compared with high FGF receptor expression, whereas there was no significant difference in post-operative survival between the low and high basic FGF expression groups. Increased expression of FGF receptor is correlated with the extent of malignancy and post-operative survival in human pancreatic ductal adenocarcinomas. Thus, overexpression of FGF receptor may prove to be a more useful prognostic marker than basic FGF expression level in pancreatic cancer patients.

Adult↗

PubMed1995

Expression and localization of mRNA for the 16 KD subunit of V-ATPase in the rat embryo.

Vacuolar H(+)-ATPase (V-ATPase), an enzyme composed of multisubunits, is located in the membrane of intracellular organelles (e.g., lysosomes, and endosomes) and maintains the intraorganellar acidic pH by pumping protons across the membrane. Although there is growing evidence for some important role of V-ATPase in cell proliferation and differentiation, the functional significance of V-ATPase in vivo during mammalian development remains obscure. In the present study we investigated the expression and localization of mRNA for the 16 KD subunit of V-ATPase, an essential sector for enzymatic activity, in prenatal rat by Northern blot analysis and in situ hybridization with a specific oligonucleotide probe. With Northern blot analysis, consistent expression of the mRNA was observed in the embryos throughout the period examined (E14-E20). On in situ hybridization, mRNA signal was distributed with various intensities in both the epithelial and mesenchymal tissues at embryonic day 14 (E14). In E17 and E20 embryos, localization of strong signal became more restricted to distinct mesenchymal cells such as fibroblasts adjacent to the epithelia of skin, lung, and intestine, the cells of perichondrium, and myoblasts in the process of fusion. These results suggest that V-ATPase performs specific functions during the later stages of embryogenesis, especially at sites of mesenchymal differentiation and epithelium-mesenchyme interaction.

Adenosine Triphosphatases↗

PubMed1995

The occurrence of acidic fibroblast growth factor-like immunoreactivity in subpopulations of endocrine cells in the pancreas and intestine of the rat.

A study of the immunocytochemical localization of acidic fibroblast growth factor (aFGF) in the rat digestive system using a polyclonal anti-aFGF antiserum revealed immunoreactive cells in the periphery of the islets of Langerhans and in the mucosal epithelia of the intestine, from the jejunum through the colon. In the pancreatic islet, light microscopic immunostaining of consecutive sections with anti-aFGF and anti-glucagon antisera as well as pre-embedding immuno-electron microscopy demonstrated that a FGF-like immunoreactivity belongs to the A cell. In the intestinal epithelium, the aFGF-immunoreactive cell was simultaneously reactive to anti-glucagon antiserum and was ultrastructurally identified as the L-cell, which is known to produce glucagon-like immunoreactants derived from proglucagon. Post-embedding immuno-electron microscopy further revealed that the immunoreactivity is localized in the secretory granules of A- and L-cells. These results suggest that an aFGF-like immunoreactant occurs in the populations of gastro-entero-pancreatic endocrine cells that express proglucagon.

Animals↗

PubMed1994

Expression and localization of the mRNA for DNA (cytosine-5)- methyltransferase in mouse seminiferous tubules.

DNA (cytosine-5)-methyltransferase (DNA MTase) is the only enzyme known to be involved in the methylation of mammalian DNA. Although the expression of DNA MTase gene is abundant in the testis, little is known about the role of this enzyme during spermatogenesis. We examined the distribution of DNA MTase mRNA in mouse testis by in situ hybridization histochemistry with an oligonucleotide probe. The mRNA signal was observed in the seminiferous tubules and was localized predominantly in spermatogonia and spermatocytes, particularly during the earlier steps of meiotic prophase I, with maximal intensity in the early pachytene cells. These results suggest some significant role for DNA MTase in spermatogenesis.

Animals↗

PubMed1994

Expression and localization of hepatocyte growth factor in rat submandibular gland.

By combination of in situ hybridization and immunohistochemical techniques, the expression of hepatocyte growth factor (HGF) was demonstrated in the submandibular gland of rats. Both the mRNA signal and immunoreactivity for HGF were localized exclusively to the epithelial cells of granular convoluted tubules, whereas they were absent from the other components of the submandibular gland. In the granular convoluted tubule cells, HGF-immunoreactivity was localized to the apical secretory granules, which was further substantiated by immunoelectron microscopy. These results added HGF to the list of many growth factors that are produced in the rat submandibular gland and secreted into the saliva.

Animals↗

PubMed1993

Cloning of a cDNA encoding rat intestinal 15 kDa protein and its tissue distribution.

A cDNA encoding rat intestinal 15 kDa protein was isolated and sequenced from a rat ileum-specific cDNA library. This cDNA was found to contain an open reading frame of 384 nucleotides as well as 5' (27 nucleotides) and 3' (46 nucleotides) non-coding regions. The deduced sequence of 127 amino acids was identical to that of rat I-15P which was purified from rat intestinal epithelium. The nucleotide sequence of the open reading frame exhibited 79% identity to that of the porcine gastrotropin. Northern blot analysis indicated that the same size of transcript as that of the ileum was detected in the ovary, suggesting that I-15P or a homologous protein might be involved in the metabolism of steroids in steroid hormone-producing tissues.

Amino Acid Sequence↗

PubMed1993

Basic fibroblast growth factor in rat salivary glands.

We studied the occurrence and localization of basic fibroblast growth factor (bFGF) in rat salivary glands using a specific monoclonal antibody. It was shown that the extract of rat salivary glands has a pronounced stimulatory activity on the growth of bovine capillary endothelial cells, which is blocked by the addition of an antibody against bFGF. The concentration of bFGF in the submandibular/sublingual gland, as determined by radioimmunoassay, was approximately 80% that in the brain. Immunocytochemistry revealed bFGF-immunoreactivity localized primarily in the epithelial cells lining the striated ducts and excretory ducts of the parotid, sublingual and submandibular glands. In addition, intense bFGF-immunoreactivity was observed in the granular convoluted tubule of the submandibular gland, localized predominantly in the agranular pillar cells, which lay in small numbers among the majority of weakly immunostained cells containing many apical secretory granules. At the electron-microscopic level, the immunoreactive material was distributed diffusely in the cytoplasmic matrix and nuclei of all immunoreactive cells, whereas it was absent from all cytoplasmic organelles including the secretory granules. These results indicate that bFGF is localized in different cellular and subcellular compartments from those of other growth factors in the duct system of rat salivary glands.

Animals↗

PubMed1993

Expression, localization and developmental regulation of insulin-like growth factor I mRNA in rat submandibular gland.

The mRNA for insulin-like growth factor I (IGF-I) in the submandibular gland of mature and developing rats was examined by Northern blotting and in situ hybridization with an oligonucleotide probe. In the mature adult rat, IGF-I mRNA was expressed at a higher level in the submandibular gland than in the liver, and was localized primarily in the granular convoluted tubule (GCT) cells. A 4.7-kb mRNA on Northern blots, which was expressed only slightly in the liver, proved to be the predominant size species of IGF-I transcripts in the GCT cells, and its level increased progressively with the postnatal development of GCTs in the gland. In addition, a 1.8-kb mRNA for IGF-I was also expressed at a much lower level throughout the acinar and duct systems, irrespective of age. These results have shed a light on the status of IGF-I as one of the many biologically active polypeptides that are produced in the rodent submandibular gland.

Age Factors↗

PubMed1993

A mutation in the Pax-6 gene in rat small eye is associated with impaired migration of midbrain crest cells.

The rat small eye strain (rSey) lacks eyes and nose in the homozygote, and is similar to the mouse Sey strain with mutations in the Pax-6 gene. We isolated Pax-6 cDNA clones from an rSey homozygote library, and found an internal deletion of about 600 basepairs in the serine/threonine-rich domain. At the genomic level, a single base (G) insertion in an exon generates an abnormal 5' donor splice site, thereby producing the truncated mRNA. Anterior midbrain crest cells in the homozygous rSey embryos reached the eye rudiments but did not migrate any further to the nasal rudiments, suggesting that the Pax-6 gene is involved in conducting migration of neural crest cells from the anterior midbrain.

Alternative Splicing↗

PubMed1993

Immunocytochemical localization of basic fibroblast growth factor in the rat pituitary gland.

Immunohistochemical localization of basic fibroblast growth factor (bFGF) was studied in the rat pituitary gland at light and electron microscopic levels using a specific monoclonal antibody. In the anterior lobe, bFGF-immunoreactivity was found mostly in a cell population without secretory granules, which was identified as the folliculo-stellate (FS) cell by its ultra-structure and expression of S-100 protein. The subcellular localization of the immunoreactivity in FS cell was strictly nuclear. Besides the FS cell, a minor cell population containing small granules of 60-100 nm diameter, which seemed to represent immature endocrine cells, was immunostained in the nuclei with the anti-bFGF antibody. In the intermediate lobe, a subpopulation of the S-100 protein-positive cells lining the pituitary cleft was immunoreactive for bFGF. These results imply that the agranular cell types are the main producer and/or target of rat pituitary bFGF, and that bFGF may play a role in the differentiation of pituitary endocrine cells.

Animals↗

PubMed1993

[Expression of glucocorticoid receptor gene during development of mouse embryos].

Glucocorticoid, one of the steroid hormones, has been known to play important roles on homeostasis and development. To obtain information about the effects of glucocorticoid on the mouse embryonic development, temporal and spatial expression patterns of the glucocorticoid receptor (GR) gene were examined by the Northern hybridization and in situ hybridization techniques. Transcripts of the GR gene were found on embryonic day (ED) 10 by the Northern analysis. The amount of GR mRNA increased drastically on ED12 and was thereafter maintained at similar levels. On the other hand, obvious signals of GR gene expression were never detected until ED12 by in situ hybridization. On ED14 and afterwards, many organs, i.e. the pituitary gland, tongue, thymus, lung, liver and pre-cartilage, showed a high GR expression. These tissues were previously reported to be the target organs of glucocorticoid. The abrupt increase of GR gene transcripts in the embryonic tissues corresponded with the beginning of their maturation or function. These result suggest that the timing of the GR gene transcription becoming high in the embryonic tissues coincides with the onset of their terminal differentiation and function.

Animals↗

PubMed1992

Nerve growth factor receptor (NGFR)-like immunoreactivity in the perineurial cell in normal and sectioned peripheral nerves of rats.

The occurrence of nerve growth factor receptor (NGFR)-like immunoreactivity in the perineurial cells of sympathetic and sensory nerves was analyzed in normal controls and after surgical severance. In the normal nerve trunk, no cellular elements exhibited NGFR-like immunoreactivity. Immunoreactivity was induced in the innermost perineurial cells and in all Schwann cells distal to a severed nerve. The acquisition of immunoreactivity in perineurial cells was also seen in deafferented sympathetic ganglia. On the other hand, the perineurial cells as well as axonal endings showed NGFR-like immunoreactivity consistently in the terminal region of normal nerves, and this immunoreactivity was enhanced by nerve section. The present study clearly showed that different types of nerve terminals are ensheathed to different extents by perineurial cells which were first clearly identified by their NGFR-like immunoreactivity: 1) nerve terminals were free of the perineurium far away from targets in the iris, 2) they were free of the perineurium at sites close to targets in the lingual epithelium, and 3) the perineurium ensheathed nerve terminals together with targets in Meissner's sensory corpuscle. The functional significance of the three different patterns of perineurial enclosure requires further examination.

Animals↗

PubMed1992

Immunocytochemical localization of rat intestinal 15 kDa protein, a member of cytoplasmic fatty acid-binding proteins.

Rat intestinal 15 kDa protein (I-15P) is a member of the family of cytoplasmic fatty acid-binding proteins. Using a specific antiserum against I-15P, we studied the tissue distribution and subcellular localization of this protein in the entire rat body. By immunoblot analysis of cytosolic proteins, I-15P was detected not only in the distal portion of small intestine but also in the ovary and adrenal gland. Immunohistochemically, I-15P was localized to the absorptive epithelial cells as well as a subpopulation of enterochromaffin cells in the intestine, the lutein cells in the ovary, and subpopulations of cortical cells in the adrenal gland. Furthermore, I-15P-like immunoreactivity was also demonstrated in the surface mucous cells of stomach and the granular convoluted tubule cells of submandibular gland. Immuno-electron microscopy showed that the immunoreactivity was confined to the cytoplasmic matrix region, except in the enterochromaffin cells and granular convoluted tubule cells, where it was localized in the secretory granules. The present findings suggest that I-15P plays a role in the cellular metabolism of steroids.

Adrenal Glands↗

PubMed1992

[Nerve growth factor receptor (NGFR)-like immunoreactivity in the perineurial cells of the adult rat peripheral nerves: normal appearance and response to nerve section].

The expression of the nerve growth factor receptor (NGFR)-like immunoreactivity in the perineurial cells of normal rat sensory and sympathetic nerves and after surgical severance was analyzed using a specific anti-rat NGFR monoclonal antibody (192-IgG). The perineurial cells as well as axonal endings showed NGFR-like immunoreactivity in the terminal region of normal nerves and the immunoreactivity in the terminal perineurial cells was enhanced after nerve severance. In the nerve trunk region, no cellular elements exhibited NGFR-like immunoreactivity in normal rats, but immunoreactivity was induced in the innermost perineurial cells and all Schwann cells in portions distal to the severance. These findings suggest that the perineurial cells function to provide NGF for intact and regenerating axons by binding NGF to NGFR on the perineurial cell surface.

Animals↗