Unusual phosphatase activity resistant to SDS and pronase treatments in Xenopus ovary

An unusual phosphatase, which is resistant to treatment by 5% SDS and proteolytic enzymes, was isolated as two types, 1 and 2, from pronase-treated homogenates of Xenopus ovary. The molecular sizes of types 1 and 2 were estimated as about 140 kDa and more than 2 x 10(4) kDa, respectively, by gel filtration, but as 140 and 130 kDa as a catalytic unit, respectively, by electrophoresis, implying that whereas type 1 might be composed of catalytic unit alone, type 2 is a multicomponent complex consisting of a 130-kDa catalytic unit. Both activities were sensitive to nucleases but resistant to tested proteolytic enzymes. These findings suggest that the unusual phosphatase activity is attributable to a polynucleotide.

Introduction of 6-formylcytidine into a Myb binding sequence

Single 6-formylcytidine was introduced into a oligonucleotide duplex (23 mers) as a substitute for thymidine in the Myb binding sequence of 3'-TTGAC-5'. The modified duplex showed Tm of 67 degrees C, which was six degrees lower than the Tm of the native duplex. Binding affinity of the 23-mers to the Myb protein was estimated by electrophoretic mobility shift assays, and the binding was almost completely abolished.

Retroperitoneal hemorrhage due to spontaneous rupture of adrenal myelolipoma

BACKGROUND

A very rare case of retroperitoneal bleeding due to spontaneous rupture of a large adrenal myelolipoma in a 62-year-old woman is reported.

METHODS/RESULTS

She consulted the emergency room of the Nagano Red Cross Hospital with a complaint of sudden left flank pain. A computerized tomography (CT) scan revealed a tumor with areas of fat density and hematoma in the left retroperitoneal space. After her general condition improved, an operation was performed. The tumor strongly adhered to the left kidney and a left nephrectomy with the tumor was curative. Histologic diagnosis was adrenal myelolipoma. No blood transfusion was required.

CONCLUSIONS

A CT scan is very useful in the pre-operative diagnosis of adrenal myelolipoma with retroperitoneal hemorrhage. Watch and wait treatments before operation and nephrectomy with adhered tumor are safe and curative.

Contamination levels and specific accumulation of persistent organochlorines in Caspian seal (Phoca caspica) from the Caspian sea, Russia

Persistent organochlorines, such as polychlorinated biphenyls (PCBs) including coplanar congeners, DDTs, HCHs, chlordanes (CHLs), and HCB, were determined in the blubber of Caspian seals (Phoca caspica) and their fish diet (Rutilus sp.) collected in 1993 from the northern Caspian Sea, Russia. Notable concentrations of DDTs and HCHs were found at mean values of 19 and 1.3 microg/g on wet-weight basis in adult male seals, respectively. PCB pollution in Caspian seals was not so considerable compared with those of seals that suffered mass mortality. Less gender difference of organochlorine residue levels in adult animals implies less excretion of organochlorines from the body of adult females through lactation and gestation, probably due to the higher rate of pregnancy failure. Immature seals had a wide range of organochlorine concentrations, which decreased as body length increased, suggesting dilution. Caspian seals can be considered to have higher degradation capacity for coplanar PCBs. Mean TEQs (2,3,7,8-TCDD toxic equivalents) for non-, mono- and di-ortho coplanar PCBs was 51 pg/g on wet-weight basis, which was lower than those in seals that have suffered mass mortality, but comparable to those found in Arctic seals.

Identification and characterization of Drosophila homolog of Rho-kinase

The Rho family of small GTPases and their associated regulators and targets are essential mediators of diverse morphogenetic events in development. Mammalian Rho-kinase/ROK alpha, one of the targets of Rho, has been shown to bind to Rho in GTP-bound form and to phosphorylate the myosin light chain (MLC) and the myosin-binding subunit (MBS) of myosin phosphatase, resulting in the activation of myosin. Thus, Rho-kinase/ROK alpha has been suggested to play essential roles in the formation of stress fibers and focal adhesions. We have identified the Drosophila homolog of Rho-kinase/ROK alpha, DRho-kinase, which has conserved the basic structural feature of Rho-kinase/ROK alpha consisting of the N-terminal kinase, central coiled-coil and C-terminal pleckstrin homology (PH) domains. A two-hybrid analysis demonstrated that DRho-kinase interacts with the GTP-bound form of the Drosophila Rho. Drho1, at the conserved Rho-binding site. DRho-kinase can phosphorylate MLC and MBS, preferable substrates for bovine Rho-kinase, in vitro. DRho-kinase is ubiquitously expressed throughout development, in a pattern essentially identical to that of Drho1. These results suggest that DRho-kinase is an effector of Drho1.

Inhibition of activation of human peripheral blood eosinophils by Y-24180, an antagonist to platelet-activating factor receptor

We examined the effects of Y-24180, a potent and long-acting antagonist to platelet-activating factor (PAF) receptor, on the PAF- or leukotriene B4 (LTB4)-induced activation of eosinophils using human peripheral blood in vitro. As activation markers, CD11b expression level and soluble intercellular adhesion molecule-1 (sICAM-1)-binding activity were analyzed by flow cytometry. Y-24180 significantly inhibited PAF-induced increase in the ratio of strongly positive cells for CD11b expression and sICAM-1 binding at 0.01 microM or more. WEB 2086, another PAF receptor antagonist, also inhibited the increase significantly at 1 microM or more. LTB4-induced increases in the ratio of strongly positive cells for CD11b expression and sICAM-1 binding were inhibited by Y-24180 at 1 microM, but not WEB 2086 up to 10 microM. These results indicate that Y-24180 inhibits the PAF- or LTB4-induced activation of eosinophils in human peripheral blood more potently than WEB 2086.

Distribution of Rho-kinase in the bovine brain

Rho-associated kinase (Rho-kinase) is a serine/threonine protein kinase downstream of the small GTPase Rho, which participates in signaling pathways of many cellular functions. Although Rho-kinase is implicated in the regulation of the morphology of neuronal cells, the distribution of Rho-kinase in the brain has not been elucidated yet. In this study, we investigated the distribution of Rho-kinase using three antibodies recognizing the different epitopes of Rho-kinase. Rho-kinase was abundantly expressed in the gray matter in comparison with the white matter. Strong immunoreactivity was observed in the pyramidal neurons of the cerebral cortex and hippocampus and in the Purkinje cells of the cerebellum. These results indicate that Rho-kinase is abundantly distributed in neurons and might play an important role in remodeling of neurites.

Rho-kinase-mediated pathway induces enhanced myosin light chain phosphorylations in a swine model of coronary artery spasm

OBJECTIVE

We recently demonstrated in our swine model of coronary artery spasm that enhanced myosin light chain (MLC) phosphorylations (both MLC mono- and diphosphorylations) play a central role in the pathogenesis of the spasm. However, the molecular mechanism for and the phosphorylation sites for the enhanced MLC phosphorylations were unknown. In the present study, we addressed these points using hydroxyfasudil, a novel inhibitor of protein kinases, which we found preferentially inhibits Rho-kinase.

METHODS

The specificity of the inhibitory effects of hydroxyfasudil on Rho-kinase, MLCK, MRCK beta and PKC were examined by kinase assay in vitro. The left porcine coronary artery was chronically treated with interleukin-1 beta (IL-1 beta, 2.5 micrograms). Two weeks after the operation, coronary artery vasomotion was examined both in vivo and in vitro. MLC phosphorylations were examined by Western blot analysis and the sites for the phosphorylations by anti-phosphorylated MLC antibodies that identified the monophosphorylation site as Ser19 and diphophorylation sites as Ser19/Thr18 of MLC.

RESULTS

Inhibitory effects of hydroxyfasudil was at least 100 times more potent for Rho-kinase as compared with other protein kinases tested. Intracoronary serotonin (10 micrograms/kg) caused coronary hyperconstriction at the IL-1 beta-treated site in vivo, which was dose-dependently inhibited by hydroxyfasudil (p < 0.01). The coronary segment taken from the spastic site also showed hypercontractions to serotonin in vitro, which were again dose-dependently inhibited by hydroxyfasudil (p < 0.01). Western blot analysis showed that MLC monophosphorylation was significantly greater in the spastic segment than in the control segment, while MLC diphosphorylation was noted only at the spastic segment (p < 0.01). The sites for the mono- and diphosphorylated MLC were identified as the monophosphorylated site Ser19 and diphosphorylated sites Ser19/Thr18 of MLC, respectively. Both types of MLC phosphorylations at the spastic segment were markedly inhibited by hydroxyfasudil (p < 0.01).

CONCLUSION

These results indicate that hydroxyfasudil-sensitive Rho-kinase-mediated pathway appears to mediate the enhanced MLC phosphorylations (on Ser19 and Ser19/Thr18 residues) and plays a central role in the pathogenesis of coronary artery spasm.

Effects of photoperiod on salmon GnRH mRNA levels in brain of castrated underyearling precocious male masu salmon

Previous studies have suggested that activation of salmon gonadotropin-releasing hormone (sGnRH)-producing neurons is induced by the combined effects of photoperiod and steroid hormones in underyearling males of the masu salmon, Oncorhynchus masou. The present study further assesses the effects of photoperiod and steroid hormones on sGnRH synthetic activity and examines the changes in sGnRH mRNA levels in the brains of castrated underyearling precocious male masu salmon by manipulating the photoperiod for 60 days from August through October. In castrated males in which plasma testosterone levels decreased to low levels, sGnRH mRNA levels in the preoptic area (POA) increased under a short photoperiod (8L-16D), whereas they remained at low levels under a long photoperiod (16L-8D) for a 2-month duration. In sham-operated males, sGnRH mRNA levels in the ventral telencephalon and those in the POA increased in October with testicular maturation even under a long photoperiod with a delay of 1 month compared with the short photoperiod group. These results suggest that preoptic sGnRH-producing neurons receive short photoperiodic signals and that either short photoperiod or steroid hormone secretion is required for the activation of sGnRH synthesis in underyearling precocious male masu salmon.

A role for rho-kinase in rho-controlled phospholipase D stimulation by the m3 muscarinic acetylcholine receptor

Stimulation of phospholipase D (PLD) by membrane receptors is now recognized as a major signal transduction pathway involved in diverse cellular functions. Rho proteins control receptor signaling to PLD, and these GTPases have been shown to directly stimulate purified recombinant PLD1 enzymes in vitro. Here we report that stimulation of PLD activity, measured in the presence of phosphatidylinositol 4,5-bisphosphate, by RhoA in membranes of HEK-293 cells expressing the m3 muscarinic acetylcholine receptor (mAChR) is phosphorylation-dependent. Therefore, the possible involvement of the RhoA-stimulated serine/threonine kinase, Rho-kinase, was investigated. Overexpression of Rho-kinase and constitutively active Rho-kinase (Rho-kinase-CAT) but not of kinase-deficient Rho-kinase-CAT markedly increased m3 mAChR-mediated but not protein kinase C-mediated PLD stimulation, similar to overexpression of RhoA. Expression of the Rho-inactivating C3 transferase abrogated the stimulatory effect of wild-type Rho-kinase, but not of Rho-kinase-CAT. Recombinant Rho-kinase-CAT mimicked the phosphorylation-dependent PLD stimulation by RhoA in HEK-293 cell membranes. Finally, the Rho-kinase inhibitor HA-1077 largely inhibited RhoA-induced PLD stimulation in membranes as well as PLD stimulation by the m3 mAChR but not by protein kinase C in intact HEK-293 cells. We conclude that Rho-kinase is involved in Rho-dependent PLD stimulation by the G protein-coupled m3 mAChR in HEK-293 cells. Thus, our findings identify Rho-kinase as a novel player in the receptor-controlled PLD signaling pathway.

Small GTPase RhoD suppresses cell migration and cytokinesis

Rho family small GTPases regulate organization of the actin cytoskeleton. Among them, RhoA plays essential roles in the formation of the actin stress fibers, the associated focal adhesions, and the contractile rings necessary for cytokinesis. Recently, RhoD, a novel member of Rho family has been identified. The amino acid sequences of its effector domain is distinct from those of the other Rho family proteins, suggesting its unique cellular functions. Introduction of the constitutively active form of RhoD(G26V) into fibroblasts by microinjection or transfection resulted in disassembly of the actin stress fibers and the focal adhesions, whereas the dominant negative form of RhoD(T31K) did not affect these structures. The degree of cell migration assessed by the phagokinetic tracks on a substrate covered with gold particles was diminished by the expression of RhoD(G26V) but not by RhoD(T31K). Thus, cytoskeletal alterations including the loss of stress fibers and focal adhesions by RhoD seems to lead to the retardation of cell migration. Transfection of RhoD(G26V) cDNA into cultured cells also induced multinucleation. Moreover, RhoD(G26V) microinjected into fertilized eggs and embryos of Xenopus laevis caused cleavage arrest only in the injected cells, and the uncleaved cells contained multiple nuclei. These results imply that RhoD does not affect nuclear division but can interfere with cytokinesis presumably by preventing the formation of the actin-based contractile ring. Enhancement of the stress fibers by RhoA or RhoA-activating lysophosphatidic acid was reversed by the transfection of RhoD cDNA. Accordingly, the cellular functions of RhoD are likely to be antagonistic to those of RhoA.

Metallic artifacts of coronary and iliac arteries stents in MR angiography and contrast-enhanced CT

Metallic artifacts of intravascular stents were assessed with MR angiography and contrast-enhanced spiral CT. Stainless steel showed less metal artifact than tantalum stent in CT. Metallic artifact in coronary and iliac arteries treated with tantalum stent was not remarkable in MR angiography. Contrast-enhanced CT might be preferable to assess patency of arteries treated with stainless steel stent. while MR angiography was useful in depicting intraluminal signal in tantalum stent.

Rho-associated kinase of chicken gizzard smooth muscle

Rho-associated kinase (Rho-kinase) from chicken gizzard smooth muscle was purified to apparent homogeneity (160 kDa on SDS-polyacrylamide gel electrophoresis) and identified as the ROKalpha isoform. Several substrates were phosphorylated. Rates with myosin phosphatase target subunit 1 (MYPT1), myosin, and the 20-kDa myosin light chain were higher than other substrates. Thiophosphorylation of MYPT1 inhibited myosin phosphatase activity. Phosphorylation of myosin at serine 19 increased actin-activated Mg+-ATPase activity, i.e. similar to myosin light chain kinase. Myosin phosphorylation was increased at higher ionic strengths, possibly by formation of 6 S myosin. Phosphorylation of the isolated light chain and myosin phosphatase was decreased by increasing ionic strength. Rho-kinase was stimulated 1.5-2-fold by guanosine 5'-O-3-(thio)triphosphate.RhoA, whereas limited tryptic hydrolysis caused a 5-6-fold activation, independent of RhoA. Several kinase inhibitors were screened and most effective were Y-27632, staurosporine, and H-89. Several lipids caused slight activation of Rho-kinase, but arachidonic acid (30-50 microM) induced a 5-6-fold activation, independent of RhoA. These results suggest that Rho-kinase of smooth muscle may be involved in the contractile process via phosphorylation of MYPT1 and myosin. Activation by arachidonic acid presents a possible regulatory mechanism for Rho-kinase.

CT examination of the head of the Baikal seal (Phoca sibirica)

We carried out a computerised tomographic (CT) examination to elucidate the modifications in the head related to orbital enlargement in the Baikal seal. Transverse CT images showed that (1) the external frontal contours and the frontal sinuses are compressed medially and ventrally by the orbital enlargement; (2) the caudal part of the nasal cavity and nasopharynx are compacted ventrally; and (3) the cranial cavity is displaced caudally. The neurocranium is obviously separated from the facial part in the transverse plane at the caudal region of the orbit. The disposition of the mandible, zygomatic arch, temporal bone, and the masseter, temporal, digastric and pterygoid muscles is changed by the enlarged orbit in the 3-dimensional reorganisation of the head in this species. It is suggested that adaptation for the Lake Baikal environment primarily resulted in orbital enlargement, and that the altered orbital design may subsequently have influenced the form and function of the masticatory and respiratory system.

Possible involvement of the inactivation of the Rho-Rho-kinase pathway in oncogenic Ras-induced transformation

Recent evidence has strongly suggested the involvement of Rho family small guanosine triphosphatases (GTPases) in Ras-induced transformation. To further clarify the role of Rho family GTPases in Ras-induced transformation, we examined the effects of dominant active or dominant negative forms of Rho family GTPases on the morphological changes induced by oncogenic Ras (RasV12) in Rat1 fibroblasts. The cells expressing RasV12 showed the severe disruption of actin stress fibers and cell adhesions. The coexpression of dominant active form of Rho (RhoV14) reverted not only the formation of stress fibers and focal adhesions but also cell-cell adhesions in Ras-transformed Rat1 cells. In addition, the coexpression of constitutively activated Rho-kinase, a downstream effector of Rho, restored the assembly of stress fibers and focal adhesions. Treatment of Ratl cells with lysophosphatidic acid, which is known to activate the Rho-Rho-kinase pathway, enhanced the stress fiber formation, whereas it failed to induce the stress fiber formation in the cells expressing RasV12. These results suggest that the Rho-Rho-kinase pathway may be inactivated in the cells expressing RasV12, and this may contribute to oncogenic Ras-induced transformation.

Roles of Rho-associated kinase in cytokinesis; mutations in Rho-associated kinase phosphorylation sites impair cytokinetic segregation of glial filaments

Rho-associated kinase (Rho-kinase), which is activated by the small GTPase Rho, regulates formation of stress fibers and focal adhesions, myosin fiber organization, and neurite retraction through the phosphorylation of cytoskeletal proteins, including myosin light chain, the ERM family proteins (ezrin, radixin, and moesin) and adducin. Rho-kinase was found to phosphorylate a type III intermediate filament (IF) protein, glial fibrillary acidic protein (GFAP), exclusively at the cleavage furrow during cytokinesis. In the present study, we examined the roles of Rho-kinase in cytokinesis, in particular organization of glial filaments during cytokinesis. Expression of the dominant-negative form of Rho-kinase inhibited the cytokinesis of Xenopus embryo and mammalian cells, the result being production of multinuclei. We then constructed a series of mutant GFAPs, where Rho-kinase phosphorylation sites were variously mutated, and expressed them in type III IF-negative cells. The mutations induced impaired segregation of glial filament (GFAP filament) into postmitotic daughter cells. As a result, an unusually long bridge-like cytoplasmic structure formed between the unseparated daughter cells. Alteration of other sites, including the cdc2 kinase phosphorylation site, led to no remarkable defect in glial filament separation. These results suggest that Rho-kinase is essential not only for actomyosin regulation but also for segregation of glial filaments into daughter cells which in turn ensures correct cytokinetic processes.

Pasteurella multocida toxin increases endothelial permeability via Rho kinase and myosin light chain phosphatase

Pasteurella multocida toxin (PMT) has been shown to induce actin reorganization through activation of the GTPase Rho. Here we investigated the involvement of the Rho target proteins Rho kinase and myosin light chain (MLC) phosphatase in the PMT-induced increase in endothelial permeability and the underlying actin reorganization of endothelial cells. Stimulation of endothelial layers with PMT enhanced transendothelial permeability > 10-fold, and this was abolished by pretreatment with the specific Rho inactivator C3 transferase from Clostridium botulinum. The PMT-induced increase in endothelial permeability was associated with 1) inactivation of MLC phosphatase, 2) an increase in MLC phosphorylation, and 3) endothelial cell retraction and actin stress fiber formation. PMT-stimulated actin reorganization could be prevented by 1) pretreatment of cells with C3 transferase, 2) microinjection of the Rho binding domain and the pleckstrin homology domain of Rho kinase, and 3) microinjection of constitutively active MLC phosphatase. Together, these results suggest that PMT activates Rho/Rho kinase, which inactivates MLC phosphatase. The resulting increase in MLC phosphorylation causes endothelial cell retraction and a rise in endothelial permeability.

Using MR imaging to predict and evaluate the response of invasive cervical carcinoma to systemic chemotherapy

OBJECTIVE

The goal of our study was to evaluate the accuracy of MR imaging in predicting the response of invasive cervical carcinoma to systemic neoadjuvant chemotherapy, to observe with MR imaging the difference in tumor response to chemotherapy between treatment cycles, and to correlate tumor size between MR imaging after chemotherapy and surgical specimen.

SUBJECTS AND METHODS

Pelvic MR imaging was performed before and after chemotherapy in 41 patients with invasive cervical carcinoma. The difference in tumor reduction between the second course and the third or fourth course of treatment was statistically evaluated in 12 patients. MR images obtained after chemotherapy were compared with surgical specimens to determine residual tumor size in 10 patients.

RESULTS

Tumor volume, complete replacement of cervical stroma with carcinoma, and uterine body involvement by tumor observed in the MR images before treatment were found to be significant factors in predicting tumor response. No difference in tumor reduction was found between the second course and the third or fourth course of chemotherapy. Estimates made on MR imaging of tumor size after chemotherapy were within 5 mm of the resected samples.

CONCLUSION

Pelvic MR imaging proved useful in predicting and assessing the response of invasive cervical carcinoma to chemotherapy.

Age-dependent accumulation of heavy metals in baikal seal (Phoca sibirica) from the Lake Baikal

Concentrations of Fe, Mn, Zn, Cu, Cd, and Hg were determined in the liver, kidney, and muscle of 60 Baikal seals collected from Lake Baikal in 1992 to investigate age-dependent accumulation. Among essential elements, Fe concentrations in the muscle, liver, and kidney increased with age, suggesting development of diving ability. The concentrations of Mn, Zn, and Cu decreased with age, especially at immature stages. Toxic elements such as Hg and Cd decreased in adult males and thus the male-female difference was clearly observed in their concentrations, which differed from patterns usually found in marine mammals. Such accumulation patterns were due to difference in the feeding rates between males and females under low exposure to Hg and Cd. In addition, a greater excretion of Hg than that of Cd through molting and parturition was estimated.

Ontogenic development of salmon GnRH and chicken GnRH-II systems in the brain of masu salmon (Oncorhynchus masou)

Ontogenic development of salmon gonadotropin-releasing hormone (GnRH) and chicken GnRH-II systems in masu salmon (Oncorhynchus masou) was examined. Salmon GnRH was first detected by radioimmunoassay in the embryo on day 36 after fertilization. Salmon GnRH-immunoreactive fibers were detected initially by immunocytochemistry in the vicinity of the olfactory placode of the embryo (day 36) and were distributed widely in the brain as well as in the pituitary gland of fish just after hatching (day 80). Salmon GnRH-immunoreactive neuronal somata were first detected about 6 months after fertilization in the rostroventral brain area, ranging from the olfactory nerve to the preoptic area. Salmon GnRH neuronal somata were detected earlier by in situ hybridization than by immunocytochemistry. Neuronal somata expressing salmon GnRH mRNA were first detected in the vicinity of the olfactory epithelium on day 40 and then were seen to be migrating from the olfactory epithelium, along the olfactory nerve, on day 60 and in the transitional area between olfactory nerve and olfactory bulb on day 80. In the brain, these neurons were first detected in the ventral olfactory bulb on day 80, and thereafter they were also detected in the caudal brain regions. The chicken GnRH-II system was detected later than the salmon GnRH system; chicken GnRH-II was first detected by radioimmunoassay on day 57, and chicken GnRH-II-immunoreactive fibers were first detected on day 67. Chicken GnRH-II-immunoreactive neuronal somata were not detected during the observation period. These results suggest that salmon GnRH neurons derive from the olfactory placode and then migrate into the brain and that salmon GnRH is synthesized before chicken GnRH-II.

Thrombin inactivates myosin light chain phosphatase via Rho and its target Rho kinase in human endothelial cells

The role of Rho GTPase and its downstream targets Rho kinase and myosin light chain phosphatase in thrombin-induced endothelial cell contraction was investigated. The specific Rho inactivator C3-transferase from Clostridium botulinum as well as microinjection of the isolated Rho-binding domain of Rho kinase or active myosin light chain phosphatase abolished thrombin-stimulated endothelial cell contraction. Conversely, microinjection of constitutively active V14Rho, constitutively active catalytic domain of Rho kinase, or treatment with the phosphatase inhibitor tautomycin caused contraction. These data are consistent with the notion that thrombin activates Rho/Rho kinase to inactivate myosin light chain phosphatase in endothelial cells. In fact, we demonstrate that thrombin transiently inactivated myosin light chain phosphatase, and this correlated with a peak in myosin light chain phosphorylation. C3-transferase abolished the decrease in myosin light chain phosphatase activity as well as the subsequent increase in myosin light chain phosphorylation and cell contraction. These data suggest that thrombin activates the Rho/Rho kinase pathway to inactivate myosin light chain phosphatase as part of a signaling network that controls myosin light chain phosphorylation/contraction in human endothelial cells.

CD1 expression defines subsets of follicular and marginal zone B cells in the spleen: beta 2-microglobulin-dependent and independent forms

We have used multicolor FACS analysis, immunohistology, and functional assays to study the expression of CD1 on B cell subsets from normal and beta 2m-/- mice. Two B cell subpopulations were identified that express high levels of CD1 in normal mice: splenic marginal zone B cells (IgMhigh IgDlow CD21high CD24intermediate CD23- CD43-) and a newly identified subpopulation of follicular B cells. The latter cells are unusual, because they are IgDhigh CD23+, like follicular B cells, but express high levels of CD21 and IgM, an expression pattern that is associated with marginal zone B cells. Therefore, the high-level expression of CD1 and CD21 was found to be closely associated on splenic B cells. Immunohistology confirmed the expression of CD1 on marginal zone B cells and on clusters of B cells in splenic follicles. Both the high-level CD1 expression by these cells and the low-level CD1 expression by subpopulations of B cells in the spleen, lymph node, peritoneal cavity, and bone marrow were markedly reduced in beta 2m-/- mice. Despite this, a CD1-restricted T cell clone proliferated vigorously in response to LPS-activated spleen cells that had been obtained from both beta 2m-/- and wild-type mice. This response was inhibited by the 3C11 anti-CD1 mAb. These results show the heterogeneity of B cell subsets in their expression of the beta 2m-dependent form of CD1. They further suggest that a beta 2m-independent form of CD1 is expressed on B cells that can stimulate T cells; however, this form is not easily visualized with the anti-CD1 mAb used here.

[PyNPase expression and cancer progression in the colorectum]

We analyzed PyNPase expression discriminating between cancer and tumor stroma of the colorectum by Western blotting using a newly developed extraction method from microdissected tissue sections fixed with buffered formalin. Analysis of 98 colorectal cancers revealed that PyNPase was as high as 70.2 +/- 18.5 unit/mg protein in the stroma fraction (SF), whereas it was 45.1 +/- 10.5 in the cancer fraction (CF) (p < 0.0001). Vessel density was correlated with PyNPase in the SF but not in the CF. In stage IIIb, 11 cases expressing a high level of PyNPase in the CF showed poorer prognosis than 10 cases with low-level PyNPase expression (p < 0.05), although the level of PyNPase expression in the SF did not affected the patients prognosis. Immunohistochemical examination indicated that PyNPase in the SF was mainly produced by macrophages (M phi), and therefore we investigated the profile of PyNPase production by M phi. In in vitro experiments PyNPase production by M phi was greatly enhanced by stimulation with OK-432, and the culture supernatant had the ability to convert 5'DFUR to 5-FU.

Comparison of the structural characteristics of chromosome VI in Saccharomyces sensu stricto: the divergence, species-dependent features and uniqueness of saké yeasts

Previous studies have revealed that chromosome VI of saké yeasts is much larger than that of the other strains of Saccharomyces cerevisiae. Southern analysis using segments of chromosome VI of a laboratory strain as probes suggested that the nucleotide sequence of a major portion of this chromosome is conserved, but considerable diversity was found in the distal parts in the other strains. Physical maps also indicated that differences in length of chromosome VI were mainly due to differences in its ends. NotI was found to generate 9 kb and/or 16 kb fragments from the left telomere of chromosome VI in most saké yeasts, but no fragment in the case of AB972. SfiI produced one or two 30-50 kb fragments from the right end of this chromosome in all saké yeasts tested, but produced a 20 kb fragment in the case of AB972. All S. cerevisiae strains not employed in saké brewing were the same as AB972 in these respects. S. paradoxus had one NotI site in chromosome VI, while S. bayanus had two, one of which is possibly common to both species. The SfiI site mentioned above was present in chromosome VI of all species, while that of S. bayanus and S. paradoxus each had a second site distinct from the other. Chromosome VI of S. pastorianus was not distinguishable from that of S. bayanus.

Primary cancer of the small intestine and mutational analysis of the K-ras and p53 genes

A 69-year-old woman was admitted to Hokuso Shiroi Hospital because of recurrent pain in the lower right side of the abdomen. Small-intestinal cancer was strongly suspected after fluoroscopy of the small intestine. Laparotomy showed advanced cancer of the ileum, of complete annular constrictive type, 9.5 x 5cm in size. Histologically it was moderately differentiated tubular adenocarcinoma. Neither visceral nor nodal metastases were found, and the patient has been well for the 20 months since surgery. The strong resemblance between the epidemiological characteristics of small-intestinal cancers and colorectal cancers prompted us to investigate the carcinogenetic mechanisms at the molecular level. A point mutation at codon 12 of the K-ras gene was found, while no alterations were noted in the p53 gene, whose mutations are frequent in colon cancers. The carcinogenetic mechanisms of the small-intestinal cancer we experienced may thus differ from those of colon cancers.