Immunohistochemical analysis of steroidogenic enzymes in ovarian‐type stroma of pancreatic mucinous cystic neoplasms: Comparative study of subepithelial stromal cells in intraductal papillary mucinous neoplasms of the pancreas

Mucinous cystic neoplasms (MCNs) are generally defined as cyst‐forming epithelial neoplasms that arise in the pancreas and harbor characteristic ovarian‐type stroma beneath the epithelium. In this study, we compared the immunoreactivity of steroid‐related factors in these subepithelial stromal cells in MCNs to those in intraductal papillary mucinous neoplasms (IPMNs) to further characterize this unique MCN ovarian‐type stroma through evaluation of sex steroid biosynthesis. Twenty MCNs and twenty IPMNs were examined. Immunoreactivity of steroid hormone receptors, including estrogen receptor (ERα and ERβ), progesterone receptor (PR, PR‐A, and PR‐B), and androgen receptor (AR), was more frequently detected in MCN ovarian‐type stromal cells than in IPMN stromal cells (P < 0.01). The H‐scores (mean ± SD) of steroidogenic factor (SF)‐1 were also significantly higher in MCNs (112.3 ± 33.1) than in IPMNs (0.9 ± 1.2) (P < 0.01). The steroidogenic enzymes cytochrome P450 cholesterol side‐chain cleavage enzyme (P450scc), cytochrome P450 17 alpha‐hydroxylase (P450c17) and 3β‐hydroxysteroid dehydrogenase (3β‐HSD) showed immunoreactivity in 9/20 (45.0 %), 15/20 (75.0 %) and 13/20 (65.0 %), respectively, of ovarian‐type stroma from MCN cases. These results demonstrate that the ovarian‐type stroma of MCNs can express steroidogenic enzymes. Thus, the ovarian‐type stroma of MCNs can produce sex steroids that may also act on these cells.     

Reversible sclerosing cholangitis with ulcerative colitis

Sclerosing cholangitis (SC) with granulocytic epithelial lesion (GEL) responds well to immunosuppression therapy. We treated a 42‐year‐old Japanese female with ulcerative colitis, who was admitted for further evaluation of both an elevated alkaline phosphatase level and dilated intrahepatic bile ducts. A liver biopsy on the fourth hospital day revealed the infiltration of neutrophils into the bile duct epithelium, which was diagnosed as GEL. Because her ulcerative colitis was in an active stage, prednisolone (PSL) therapy was started. After the administration of PSL, laboratory data dramatically decreased. A liver biopsy was performed on the 66th hospital day to confirm the lesion around bile ducts in the portal tract. The infiltration of neutrophils into the bile duct epithelium disappeared after PSL administration, and IgG4‐positive plasma cells were not found in the liver. Herein, we report a rare case of GEL‐positive SC. The present case provides early evidence of treatment‐induced histological changes as well as serial changes in biochemical data during the course of immunosuppression therapy.     

Repetitive activation of protein kinase A induces slow and persistent potentiation associated with synaptogenesis in cultured hippocampus

Mammalian brain memory is hypothesized to be established through two phases; short-term plasticity, as exemplified by long-term potentiation (LTP) where pre-existing synapses change transmission efficiency, and long-lasting plasticity where new synapses are formed. This hypothesis, however, has not been verified experimentally. Using cultured hippocampal slices, we show that the repeated induction of late-phase LTP by brief applications of forskolin (FK) led to a slowly-developing long-lasting synaptogenesis, as judged from electrophysiological, cytological and ultrastructural indices. These indices include (1) field postsynaptic potential standardized by field action potential, which should represent the number of synapses per neuron; (2) the amounts of synaptic marker proteins; (3) the number of synaptophysin-immunopositive puncta; (4) the number of dendritic spines per length; (5) the density of synaptic ultrastructures; (6) ultrastructures similar to synapse perforation. Increment in these indices occurred approximately 10 days after FK-application and outlasted the following weeks. The increment depended on the times and intervals of FK-application. A biologically inert FK analogue failed to produce the similar effect. An inhibitor for cyclic AMP-dependent protein kinase (PKA) blocked the synaptogenesis. The cultured brain slice repeatedly exposed to FK should serve as a good model system for the analysis of persistent synaptogenesis possibly related to long-term memory in mammalian CNS.     

Overexpression of MDM2 in a sclerosing epithelioid fibrosarcoma: genetic, immunohistochemical and ultrastructural study of a case

Sclerosing epithelioid fibrosarcoma (SEF) is an extremely rare soft-tissue neoplasm. Here, we describe the molecular genetic alterations and histological, immunohistochemical and ultrastructural features of a primary SEF arising in the retroperitoneum. The tumor consisted of uniform small round to ovoid epithelioid cells, arranged in nests and cords and surrounded by a prominent hyalinized collagenous matrix. The tumor cells expressed only vimentin. Ultrastructurally, the tumor cells showed features of fibroblasts, with an abundant rough endoplasmic reticulum in the cytoplasm. Neither p53 gene mutations nor p53 protein overexpression were detected, but more than 70% of all tumor cells showed strong immunoreactivity with murine double minute 2 (MDM2). Our results suggest that MDM2 overexpression is likely to play a role in tumorigenesis in this lesion in p53-dependent or p53-independent pathways. To our knowledge, the present study is the first molecular genetic study of this rare lesion. Further studies will be necessary to clarify the molecular basis of tumorigenesis of this rare lesion.     

Glutathione redox regulates lipopolysaccharide-induced IL-12 production through p38 mitogen-activated protein kinase activation in human monocytes: role of glutathione redox in IFN-gamma priming of IL-12 production

We examined whether changes in intracellular reduced (GSH) or oxidized (GSSG) glutathione of human monocytes regulate lipopolysaccharide (LPS)-induced IL-12 production and defined the molecular mechanism that underlies glutathione redox regulation. Monocytes exposed to glutathione reduced form ethyl ester (GSH-OEt) or maleic acid diethyl ester (DEM) increased or decreased the intracellular GSH/GSSG ratio, respectively. LPS-induced IL-12 production and p38 mitogen-activated protein (MAP) kinase activation were enhanced by GSH-OEt but suppressed by DEM. Selective p38 inhibitors showed that p38 promoted GSH-OEt-enhanced IL-12 production. Furthermore, IFN-gamma priming increased the GSH/GSSG ratio and enhanced IL-12 production through p38, and DEM negated the priming effect of IFN-gamma on p38 activation and IL-12 production as well as on the GSH/GSSG ratio. These findings reveal that glutathione redox regulates LPS-induced IL-12 production from monocytes through p38 MAP kinase activation and that the priming effect of IFN-gamma on IL-12 production is partly a result of the glutathione redox balance.     

In Vitro Regulation of CaCO3 Crystal Growth by the Highly Acidic Proteins of Calcitic Sclerites in Soft Coral,Sinularia Polydactyla

Acidic proteins are generally thought to control mineral formation and growth in biocalcification. Analysis of proteinaceous components in the soluble and insoluble matrix fractions of sclerites in Sinularia polydactyla indicates that aspartic acid composes about 60% of the insoluble and 29% of the soluble matrix fractions. We previously analyzed aspartic acids in the matrix fractions (insoluble = 17 mol%; soluble = 38 mol%) of sclerites from a different type of soft coral, Lobophytum crassum, which showed comparatively lower aspartic acid-rich proteins than S. polydactyla. Thus, characterization of highly acidic proteins in the organic matrix of present species is an important first step toward linking function to individual proteins in soft coral. Here, we show that aspartic-acid rich proteins can control the CaCO₃ polymorph in vitro. The CaCO₃ precipitates in vitro in the presence of aspartic acid-rich proteins and 50 mM Mg²⁺ was verified by Raman microprobe analysis. The matrix proteins of sclerites demonstrated that the aspartic-acid rich domain is crucial for the calcite precipitation in soft corals. The crystalline form of CaCO₃ in the presence of aspartic acid-rich proteins in vitro was identified by X-ray diffraction and, revealed calcitic polymorphisms with a strong (104) reflection. The structure of soft coral organic matrices containing aspartate-rich proteins and polysaccharides was assessed by Fourier transform infrared spectroscopy. These results strongly suggest that the aspartic acid-rich proteins within the organic matrix of soft corals play a key role in biomineralization regulation.     

HTLV-I-infected T cells activate autologous CD4+ T cells susceptible to HTLV-I infection in a co-stimulatory molecule-dependent fashion

A vigorous production of human T lymphotropic virus type I (HTLV-I)-infected CD4⁺ T cells is closely associated with the development of adult T cell leukemia (ATL) and neurological disease. However, the immunological mechanisms leading to generation of the HTLV-I-infected cells are not fully clarified. The modulation of CD80 and CD86 expression on the HTLV-I-infected cells and its physiological role in the interaction of infected CD4⁺ T cells with uninfected CD4⁺ T cells was examined. The HTLV-I-infected CD4⁺ T cell lines established from ATL patients and normal donors by infecting their CD4⁺ T cells with the virus expressed CD80, CD86, and HLA-DR, and induced a proliferation of autologous and allogenic CD4⁺ T cells. While the CD4⁺ T cells stimulated with the autologous HTLV-I-infected cells for 7 days expressed CD80 and CD86 but not HTLV-I gene products, they expressed HTLV-I gag antigen after 4 weeks. The interaction of HTLV-I-infected and -uninfected CD4⁺ T cells was profoundly suppressed by a combination of CD80 and CD86 monoclonal antibodies. These results suggest that the induction of CD80 and CD86 on HTLV-I-infected CD4⁺ T cells participates actively in the generation of the virus-infected progenitor cells.     

The sustained inward current in sino-atrial node cells of guinea-pig heart

 Single myocytes were dissociated from the sino-atrial (SA) node of guinea-pig hearts. Only a quite small fraction of the cell population showed spontaneous action potentials and these cells were characterized by the presence of the hyperpolarization-activated cation current I _f , the delayed rectifier K⁺ current I _K and the L-type Ca²⁺ current I _Ca,L as well as by the absence of both the transient outward current I _to and the inward rectifier K⁺ current I _K,1. After blocking I _f and I _K, depolarizing pulses from –80 mV revealed a large nicardipine-sensitive late current (NSLC). The NSLC was scarcely affected by decreasing extracellular [Ca²⁺] ([Ca²⁺]_o) from 1.8 to 0.1 mM, while it was decreased significantly by depleting [Na⁺]_o, differently from I _Ca,L. NSLC was blocked by nicardipine and was increased by Bay K 8644. NSLC was increased by isoprenaline and the additional application of acetylcholine reversed the increase of this current. We conclude that NSLC is largely composed of I _st described in the rabbit SA node pacemaker cells, and that I _st is unique for the pacemaker cells in mammalian SA node cells. Most of the quiescent cells showed neither I _f nor I _st. Received: 22 July 1996 / Received after revision: 30 September 1996 / Accepted: 9 October 1996