Clinicopathological significance of EZH2 mRNA expression in patients with hepatocellular carcinoma

Enhancer of zeste homologue 2 (EZH2), a member of the polycomb group protein family, plays a crucial role in the regulation of embryonic development and has been associated with the regulation of the cell cycle. Recently, several studies have shown that EZH2 is highly expressed in aggressive tumours, including human breast cancer, prostate cancer, and lymphomas. We thus analysed EZH2 expression using real-time reverse transcription-polymerase chain reaction, and correlated its expression status with various clinicopathological parameters in 66 patients with hepatocellular carcinoma (HCC). We found high expression of EZH2 in human liver cancer cell lines. Furthermore, EZH2 gene-expression levels in tumour tissue specimens (0.34+/-0.52) were significantly higher (P<0.0001) than those in the corresponding nontumour tissue specimens (0.07+/-0.09). The incidence of cancer cell invasion into the portal vein was significantly higher (P<0.001) in the high EZH2 expression group (26 of the 33, 79%) than in the low expression group (13 of the 33, 39%). However, there was no significant difference in the disease-free survival rate between the two groups. The findings of this study indicate that EZH2 mRNA expression was upregulated in human HCC and may play an important role in tumour progression, especially by facilitating portal vein invasion.

Clinical significance of enhancer of zeste homolog 2 expression in colorectal cancer cases

INTRODUCTION

Enhancer of zeste homolog 2 (EZH-2) is a polycomb group (PcG) protein, and the clinical significance of this protein has not yet been determined in colorectal cancer (CRC) cases. Recently, investigations of CRC cases have focused on the interaction between EZH-2 and histone deacetylase-1 (HDAC-1).

PATIENTS AND METHODS

We performed real time RT-PCR to evaluate the expression of EZH-2 mRNA quantitatively in tumour and normal tissue samples from 61 cases of CRC. The expression of HDAC-1 in CRC cases was also examined in order to compare its levels with those of EZH-2.

RESULTS

Among the CRC cases, 32 patients whose tumour tissue showed overexpression of EZH-2 also had a significantly worse prognosis than did 29 patients whose tumour tissue showed low EZH-2 expression (p<0.05). In addition, a significant correlation between EZH-2 and HDAC-1 expression was observed in 61 CRC cases (p<0.05). Moreover, 20 cases of both high EZH-2 and high HDAC-1 expression showed poor prognoses than did 19 cases in which there was low EZH-2 and low HDAC-1 expression (p<0.05).

CONCLUSION

The abundant expression of EZH-2 in CRC cases indicated that EZH-2 may be an oncogene and a prognostic marker for CRC cases. We discovered there was concordant expression of HDAC-1 with EZH-2 in clinical CRC cases, in addition to the fact that higher expression levels of both genes predicted a poor prognosis.

[Ruptured thoracic aortic aneurysm presenting as massive epistaxis; report of a case]

An 80-year-old woman was transported to the emergency room at our hospital by the ambulance, suffering from massive epistaxis. As the patient was hemodynamically stable, otolaryngologist attempted to perform tamponade using nasal packing. However, the patient's condition deteriorated, with the development of dyspnea and a reduction in oxygen saturation to 90%. A chest X-ray performed at this point revealed left lung consolidation and pleural effusion while chest computed tomography (CT) demonstrated that rupture of a descending aortic aneurysm with periaortic hematoma and extension of hemorrhage into the left lower lobe of the lung. Emergency surgery was performed under partial extracorporeal circulation, established by cannulation of the right femoral artery and vein. In addition to the replacement of the descending aorta with a prosthetic conduit, left lower lobectomy was necessary because of severe adhesion to the descending aorta. The postoperative course was largely uncomplicated apart from development of chylothorax, which resolved with a short period of total parenteral nutrition and she was discharged 50 days after surgery.

Esophageal perforation caused by a press through pack

A 73-year-old woman complaining of sudden hoarseness visited our hospital 17 days after the onset. The upper gastrointestinal contrast study showed a shallow ulcer crater with moderate bulging in the upper thoracic esophagus. Endoscope and computed tomography revealed an esophageal foreign body, a Press Through Pack (PTP), in the esophageal ulcer. The PTP could be removed endoscopically. Two months after extraction of the PTP, the patient was taking normal food orally and was discharged. The esophageal perforation, looking like a diverticle, was still present more than 1 year after the onset.

Cyclic AMP specific phosphodiesterase activity and colon cancer cell motility

To investigate mechanisms for regulation of intracellular cAMP involved in cancer cell invasion, phosphodiesterase (PDE) activity in a colon cancer cell line, DLD-1, was studied. Activities of PDE 2, 4, and 5 were detected in DLD-1 cells by pharmacological approach. Specific and cell permeable inhibitors for those PDEs were used to determine which PDE is responsible for cAMP turnover involved in cancer cell motility. Treatment of DLD-1 cells with rolipram and Ro-20-1724 inhibitors for PDE 4, elevated intracellular cAMP contents three to five times of control. EHNA, an inhibitor for PDE 2, and zaprinast. an inhibitor for PDE 5, did not affect cAMP levels. To assess cellular motility, we utilized chemotaxis assay. EHNA and zaprinast did not suppress serum-induced chemotaxis. In contrast, rolipram and Ro-20-1724, suppressed chemotaxis in a dose dependent fashion. These suggest that PDE 4 plays a critical role in regulating intracellular cAMP levels of colon cancer cells and is involved in cancer invasion. PDE 4 can be a novel target of anti-invasion drug.

Study on PDGF receptor beta pathway in glomerular formation in neonate mice

The assembly of vascular endothelial cells (ECs) and smooth muscle cells is a critical event in the development of the cardiovascular system. Although the role of ECs in this event has been studied intensively, the cross-talk between the two cell components remains poorly understood. In this study, we blocked platelet-derived growth factor receptor (PDGFR) pathways in mice by antagonistic rat monoclonal antibody APB5 against murine PDGFR-beta and examined glomerular capillary formation.

Possible involvement of p38 mitogen-activated protein kinase in decidual function in parturition

We designed the present study to elucidate the molecular mechanism for parturition, focusing on p38 mitogen-activated protein kinase (p38). The kinase activity of p38 in mouse uterus was gestation stage-dependent, and was markedly increased on day 19 of gestation and during labor. Immunohistochemical examination with anti-phospho p38 antibody revealed that activated p38 was predominantly localized in decidual stromal cells stained with anti-prolactin antibody. In human primary cultured decidual cells, a p38 inhibitor, SB202190, significantly inhibited both prostaglandin F(2alpha) production and COX-2 expression induced by stimulation with IL-1beta. These results suggest that the p38 signaling pathway is involved in decidual function at the late stage of gestation and may contribute to parturition.

Bradykinin and angiotensin II-induced [Ca2+]i rise in cultured rat pituitary folliculo-stellate cells

Folliculo-stellate cells of the anterior pituitary are thought to modulate pituitary hormone secretion through a paracrine mechanism. Angiotensin II and pituitary adenylate cyclase-activating polypeptide (PACAP) have previously been shown to increase the intracellular Ca2+ concentration ([Ca2+]i) of these cells. In the present study, we examined the effects of various peptides such as bradykinin, angiotensin II, endothelin-1, PACAP, galanin and neurotensin by Ca2+-imaging of folliculo-stellate cells in primary culture. Bradykinin and angiotensin II increased [Ca2+]i in folliculo-stellate cells. Both responses were completely suppressed by thapsigargin and were significantly suppressed by the phospholipase C inhibitor, U-73122. Ryanodine did not significantly modify the responses. A B2 antagonist and angiotensin II receptor antagonist inhibited the response induced by bradykinin and angiotensin II, respectively. Endothelin-1 and PACAP increased [Ca2+]i in fewer than 50% of folliculo-stellate cells but galanin and neurotensin did not influence [Ca2+]i in any of the folliculo-stellate cells tested. These results indicate that bradykinin and angiotensin II increase [Ca2+]i in folliculo-stellate cells by activating phospholipase C through B2 receptor and AT1 receptor, respectively, and that endothelin-1 and PACAP also increase [Ca2+]i in some folliculo-stellate cells.

Estimation of anti-platelet drugs on human platelet aggregation with a novel whole blood aggregometer by a screen filtration pressure method

1. The effects of anti-platelet drugs on human whole blood aggregation were evaluated using a novel whole blood aggregometer by a screen filtration pressure (SFP) method. 2. The SFP whole blood aggregometer was found to successfully detect whole blood aggregation induced by ADP, collagen and TRAP by measuring the SFP of blood samples. The platelet aggregation threshold index (PATI), the concentration of agonist required with an inducing pressure rate of 50%, varied time-dependently after collection of blood. High values for ADP and collagen were noted immediately after blood collection, suggesting low aggregation activity of platelets, and gradually increase thereafter. 3. Cilostazol (phosphodiesterase 3 inhibitor), dipyridamole, aspirin and tirofiban all inhibited whole blood aggregation in vitro. Inhibitory effects of cilostazol and dipyridamole, but not tirofiban, were markedly enhanced 6 or 7 fold by long pre-incubation (60 min), compared with short pre-incubation (2 min). Such enhancement was only observed with ADP- and not collagen-induced whole blood aggregation. A similar phenomenon was also observed for aggregation with platelet rich plasma (PRP). Cilostazol inhibition of ADP-induced platelet aggregation was more potent with PRP than whole blood (PATI(200)=3.80+/-0.95 microM for whole blood; 2.04+/-0.61 microM for PRP). Inhibitory effects of dipyridamole were attenuated in PRP without erythrocytes. 4. These results demonstrate that the SFP aggregometer can sensitively detect anti-platelet aggregatory effects of various kinds of drugs. So that it is a useful tool for evaluation of anti-platelet drugs.

Augmentation of the pharmacological action of corydalis tuber by saussurea root in isolated mouse ileum

To understand the meaning of blending crude drugs in Chinese medicinal prescriptions, the influence of Saussurea root on the pharmacological action of Corydalis tuber was examined. Saussurea root increased the depression of acetylcholine-induced contraction caused by the hot water extract solution of Corydalis tuber in mouse ileum at low dosage, which showed no direct influence on acetylcholine. Dehydrocostuslactone in Saussurea root was characterized as the component having increasing activity and the relationship between the concentration of acetylcholine and the variation in the contraction depressed by Corydalis tuber alone or a mixture of the Corydalis tuber and dehydrocostuslactone was investigated for clarification of the mode of action.

Functional blockade of platelet-derived growth factor receptor-beta but not of receptor-alpha prevents vascular smooth muscle cell accumulation in fibrous cap lesions in apolipoprotein E-deficient mice

BACKGROUND

The vascular smooth muscle cell (VSMC) is the central cell component involved in the fibroproliferative response in atherogenesis. As the lesion advances, VSMCs migrate from the media into the subendothelial space, thereby forming fibrous plaque lesions. Platelet-derived growth factor (PDGF) has been known to be a potent chemoattractant and mitogen for SMCs, but the pathophysiological role of the 2 PDGF receptors, receptor-alpha (PDGFR-alpha) and receptor-beta (PDGFR-beta) in atherogenesis is poorly understood. To clarify this problem, we prepared antagonistic rat monoclonal antibodies, APA5 and APB5, against murine PDGFR-alpha and PDGFR-beta, respectively.

METHODS AND RESULTS

Apolipoprotein E-deficient mice were fed a high-fat diet containing 0.3% cholesterol from 6 weeks of age and subjected to injection with 1 mg/d IP of either antibody from 12 to 18 weeks every other day. In the mice injected with APB5, the aortic atherosclerotic lesion size and the number of intimal VSMCs were reduced by 67% and 80%, respectively, compared with the control mice injected with irrelevant rat IgG. In contrast, the mice that received APA5 showed only minimal reduction of lesion size, and a large number of VSMCs were observed in the intima. In the intima of advanced lesions, APB5 immunolabeled VSMCs, whereas APA5 could detect VSMCs mainly in the media.

CONCLUSIONS

These results indicate that PDGFR-beta plays a significant role in formation of fibrous atherosclerotic lesions and that regulation of the signal transduction through PDGFR-beta could affect atherogenesis in mice.

Electroporation-mediated PDGF receptor-IgG chimera gene transfer ameliorates experimental glomerulonephritis

BACKGROUND

Mesangial cell proliferation and phenotypic alteration occur in an early phase of glomerular injury and precede increased extracellular matrix accumulation. A critical growth factor responsible for mesangial proliferation is platelet-derived growth factor (PDGF), which has proved to be a potent mitogen.

METHODS

We generated a chimeric cDNA encoding an extracellular domain of the beta-PDGF receptor fused with IgG-Fc, termed PDGFR/Fc, and examined the feasibility of gene therapy targeting PDGF using PDGFR/Fc.

RESULTS

Chimeric PDGFR/Fc molecule completely inhibited the tyrosine phosphorylation of beta-PDGF receptors and cellular proliferation induced by PDGF in vitro. We then introduced the PDGFR/Fc expression vector into the muscle of anti-Thy-1 model of glomerulonephritic rats by electroporation. The plasma concentration of chimeric PDGFR/Fc levels was 244.4 +/- 89.8 ng/mL four days after transfection. On day 5, PDGFR/Fc gene transfer significantly reduced the number of PCNA-positive cells and glomerular cell numbers by 59.6 and 23.2%, respectively. Northern blot analysis demonstrated that glomerular mRNA levels of alpha-smooth muscle action, transforming growth factor-beta 1, and type I collagen were also suppressed on days 5 and 7 by the PDGFR/Fc transfection. There was a significant reduction in the matrix score of the transfected nephritic rats (2.91 +/- 0.75 and 2.06 +/- 0.95; disease control group vs. treated group, P < 0.001).

CONCLUSION

These results suggest that gene therapy by the manipulation of PDGF action using electroporation-mediated PDGFR/Fc gene transfer to the skeletal muscle might be a useful treatment for mesangioproliferative glomerulonephritis.

dlk inhibits stem cell factor-induced colony formation of murine hematopoietic progenitors: Hes-1-independent effect

Delta-like (dlk) is a family of transmembrane proteins containing epidermal growth factor-like repeat motifs homologous to the notch/delta/serrate family. Recent studies suggest that dlk is a negative regulator of adipocyte differentiation, a promoting factor of cobblestone area colony formation, and a molecule which influences stromal cell-pre-B cell interactions and augments cellularity of developing thymocytes. However, the role of dlk in regulating the growth and differentiation of hematopoietic progenitors remains unclear. In the present study, we examined the effect of dlk on the proliferation of murine hematopoietic progenitors by hematopoietic growth factors. Soluble dlk-IgG Fc chimeric protein completely inhibited the colony formation of lineage-marker negative (Lin-) bone marrow cells by GM-CSF, G-CSF, or macrophage-CSF (M-CSF) in the presence of stem cell factor (SCF). However, dlk failed to inhibit the colony formation of Lin- bone marrow cells by CSF, as described above, or M-CSF plus interleukin 3. Furthermore, dlk failed to inhibit the colony formation of Hes-1-null fetal liver cells by M-CSF in the presence of SCF. These findings suggest that dlk is an important regulator of hematopoietic progenitor proliferation. Depending on the presence of SCF, dlk may act as a growth inhibitor, although dlk signaling does not mediate Hes-1 transcription factor.

Population pharmacokinetic modeling and model validation of a spicamycin derivative, KRN5500, in phase 1 study

PURPOSE

KRN5500, a novel spicamycin derivative, shows the greatest activity against a human tumor xenograft model and the highest therapeutic index among spicamycin derivatives. KRN5500 is currently under clinical development in Japan and the United States. The objective of this study was to develop a population pharmacokinetic model that describes the KRN5500 plasma concentration versus time data.

METHODS

Data were collected from 18 patients entered in a phase 1 study. These patients received KRN5500 3-21 mg/m2 as a 2-h infusion. A total of 219 concentration measurements were available. The data were analyzed using the nonlinear mixed effect model (NONMEM) program. In addition, the basic and final population pharmacokinetic models were evaluated using bootstrapping resampling.

RESULTS

The basic model selected was a two-compartment model with a combination of additive and constant coefficient of variation error models. The basic model fitted well not only the original data, but also 100 bootstrap replicates generated from the original data set. With regard to the effect of covariates selected by generalized additive modeling analysis, gender (SEX) and performance status were found to be possible determinants of the volume of central compartment by NONMEM analysis. The final regression model for V1 was V1 = theta V1 (1--SEX x theta SEX), where V1 is the typical population value of the volume of central compartment, and SEX = 0 if the patient is male, otherwise SEX = 1. The final model was fitted to the 200 bootstrapped samples. The mean parameter estimates were within 15% of those obtained with the original data set.

CONCLUSIONS

The KRN5500 plasma concentration versus time data obtained from the phase 1 study were well described by the population pharmacokinetic model. Further evaluation by bootstrapping showed that the population pharmacokinetic model was stable.

Characterization of whole blood aggregation with a new type of aggregometer by a screen filtration pressure method

A new type of platelet aggregometer of whole blood, based on the screen filtration pressure method, has been developed and characterized. It measures resistance of flow of whole blood samples through a screen of microsieve with 30-microm(2) openings and provides pressure rate as an index of platelet aggregation. On optical microscopic observation, platelet aggregates, but not fibrin fibers, were found to be trapped on microsieves, and the pressure rate and protein amounts on microsieves are correlated. The aggregometer showed good reproducibility for investigations performed on different days. The time course of pressure rates indicated a bell curve change, where the pressure rate was very low immediately after blood collection and gradually increased up to 60 min thereafter. Use of the aggregometer was able to confirm that orally administered aspirin inhibits ADP- and collagen-induced whole blood aggregation as well as platelet aggregation. The results suggest that this platelet aggregometer might be useful in research and clinical diagnosis of thrombotic diseases.

Immunolocalization of p38 MAP kinase in mouse brain

p38 has been implicated to play a critical role in regulating apoptosis in PC12 and cerebellar granule cells, and is inactivated in cultured fetal neurons in response to insulin. Though p38 is activated in microglia after ischemia, the physiological functions of p38 in the brain are not well understood. As a first step to elucidate the physiological functions of p38 in the central nervous system, we raised a polyclonal antibody against p38 and performed immunohistochemical examination to demonstrate the localization of p38 in mouse brain. Strong p38 immunoreactivity was apparent in fiber bundles including the olfactory tract, anterior commissure, corpus callosum, cingulum, internal capsule, stria terminalis, fimbria and alveus hippocampi, fornix, stria medullaris, optic chiasm and optic tract. Although similar regions were stained with both anti-p38 and anti-neurofilament antibodies, intense p38 immunoreactivity was often observed in myelin sheath-like structures but not in axons. This is the first demonstration of the localization of p38 in the central nervous system and provides an anatomical basis for understanding physiological roles of p38.

Activation of p38 mitogen-activated protein kinase is crucial in osteoclastogenesis induced by tumor necrosis factor

Tumor necrosis factor (TNF) induces osteoclast differentiation from bone marrow cells in the presence of macrophage colony-stimulating factor. Treatment of bone marrow cells with SB203580 but not PD98059 inhibited TNF-induced osteoclast differentiation. In RAW264 cells which differentiate into osteoclast-like multinucleated cells by TNF treatment alone, activation of p38 mitogen-activated protein (MAP) kinase induced by murine TNF was comparable to and independent of the receptor activator of necrosis factor-kappaB ligand. Moreover, the number of multinucleated osteoclasts induced by TNF in bone marrow cell cultures derived from p38 MAP kinase gene deficient mice was significantly less than that from control mice. These results indicate that the p38 MAP kinase pathway plays a crucial role in TNF-mediated osteoclast differentiation.

Involvement of p38 mitogen-activated protein kinase signaling pathway in osteoclastogenesis mediated by receptor activator of NF-kappa B ligand (RANKL)

The receptor activator of NF-kappaB ligand (RANKL) induces osteoclast differentiation from bone marrow cells in the presence of macrophage colony-stimulating factor. We found that treatment of bone marrow cells with SB203580 inhibited osteoclast differentiation via inhibition of the RANKL-mediated signaling pathway. To elucidate the role of p38 mitogen-activated protein (MAP) kinase pathway in osteoclastogenesis, we employed RAW264 cells which could differentiate into osteoclast-like cells following treatment with RANKL. In a dose-dependent manner, SB203580 but not PD98059, inhibited RANKL-induced differentiation. Among three MAP kinase families tested, this inhibition profile coincided only with the activation of p38 MAP kinase. Expression in RAW264 cells of the dominant negative form of either p38alpha MAP kinase or MAP kinase kinase (MKK) 6 significantly inhibited RANKL-induced differentiation of the cells. These results indicate that activation of the p38 MAP kinase pathway plays an important role in RANKL-induced osteoclast differentiation of precursor bone marrow cells.

Cilostazol, a selective type III phosphodiesterase inhibitor, decreases triglyceride and increases HDL cholesterol levels by increasing lipoprotein lipase activity in rats

Cilostazol, a selective type III phosphodiesterase inhibitor, has antiplatelet and vasodilating effects. In this study, the effects of cilostazol on lipid metabolism and lipoprotein lipase (LPL) activity were studied in rats. Cilostazol was administered orally at doses of 30 or 100 mg/kg twice a day for 1-2 weeks to rats. Cilostazol decreased the serum triglyceride level in normolipidemic rats. The serum triglyceride level was reduced and HDL cholesterol level was increased by cilostazol in streptozotocin (STZ)-induced diabetic rats. The disappearance of exogenous triglyceride was accelerated by cilostazol in normolipidemic rats. Cilostazol increased post-heparin plasma LPL activity but had no effect on hepatic triglyceride lipase activity in STZ-induced diabetic rats. Cilostazol also increased LPL activity in the heart in STZ-induced diabetic rats. These findings suggest that an increase in LPL activity is responsible for the serum triglyceride lowering and HDL cholesterol elevating effects of cilostazol in rats.

Nuclear transfer in cattle using colostrum-derived mammary gland epithelial cells and ear-derived fibroblast cells

To assess the developmental potential of nuclear transfer embryos in cattle using mammary gland epithelial (MGE) cells derived from the colostrum, we compared the effectiveness of cloning using those cells and fibroblast cells derived from the ear. The fusion rate of the enucleated oocytes with fibroblast cells (75 +/- 4%) was significantly higher than that with MGE cells (56 +/- 7%, P<0.05). There were no significant differences in the cleavage rate (85 +/- 3% vs. 91+/- 2%) or in the developmental rate to the blastocyst stage (35 +/- 6% vs. 35 +/- 5%) using MGE cells vs. fibroblast cells as donor nuclei (P>0.05). After transfer of blastocysts derived from nuclear transfer embryos produced using MGE cells and fibroblast cells, 13% (4/31) and 16% (6/37) of recipient heifers were pregnant on Day 42 as assessed by ultrasonography, respectively. Two of the 4 and 4 of the 6 recipients of embryos with MGE cell- and fibroblast cell-derived nuclei, respectively, aborted within 150 days of pregnancy. Four live female calves were obtained from MGE cells or fibroblast cells. However, one died from internal hemorrhage of the arteria umbilicalis. The other three calves were normal and healthy. There were no differences in the pregnancy rate or calving rate when using MGE cells vs. fibroblast cells. Microsatellite DNA analyses confirmed that the cloned calves were genetically identical to the donor cows and different from the recipient heifers. We conclude that colostrum-derived MGE cells have the developmental potential to term by nuclear transfer, and the efficiency of development of those cloned embryos was the same as that of embryos obtained using fibroblast cells as donor nuclei, although there was a significant difference in the fusion rate. This method using MGE cells derived from colostrum, which is obtained easily and safely from live adult cows, is more advantageous for cloning with somatic cells.

Basic helix-loop-helix transcription factors regulate the neuroendocrine differentiation of fetal mouse pulmonary epithelium

To clarify the mechanisms that regulate neuroendocrine differentiation of fetal lung epithelia, we have studied the expression of the mammalian homologs of achaete-scute complex (Mash1) (Ascl1 - Mouse Genome Informatics); hairy and enhancer of split1 (Hes1); and the expression of Notch/Notch-ligand system in the fetal and adult mouse lungs, and in the lungs of Mash1- or Hes1-deficient mice. Immunohistochemical studies revealed that Mash1-positive cells seemed to belong to pulmonary neuroendocrine cells (PNEC) and their precursors. In mice deficient for Mash1, no PNEC were detected. Hes1-positive cells belong to non-neuroendocrine cells. In the mice deficient in Hes1, in which Mash1 mRNA was upregulated, PNEC appeared precociously, and the number of PNEC was markedly increased. NeuroD (Neurod1 - Mouse Genome Informatics) expression in the lung was detected in the adult, and was enhanced in the fetal lungs of Hes1-null mice. Expression of Notch1, Notch2, Notch3 and Notch4 mRNAs in the mouse lung increased with age, and Notch1 mRNA was expressed in a Hes1-dependent manner. Notch1, Notch2 and Notch3 were immunohistochemically detected in non-neuroendocrine cells. Moreover, analyses of the lungs from the gene-targeted mice suggested that expression of Delta-like 1 (Dll1 - Mouse Genome Informatics) mRNA depends on Mash1. Thus, the neuroendocrine differentiation depends on basic helix-loop-helix factors, and Notch/Notch-ligand pathways may be involved in determining the cell differentiation fate in fetal airway epithelium.

Responses of tracheobronchial receptors to inhaled furosemide in anesthetized rats

Inhalation of furosemide, a loop diuretic, has shown favorable effects on experimentally induced cough, bronchoconstriction, and dyspnea. The effect of inhaled furosemide on tracheobronchial receptors was studied in anesthetized, spontaneously breathing rats. Single unit or pauci unit activity was recorded from the right vagus nerve. Tracheobronchial receptors were classified into slowly and rapidly adapting receptors (SARs and RARs, respectively), based on their adaptation index (AI), which was derived from the decrease in spike frequency (sf) over 2 s, expressed as a percentage of the peak firing rate. There were 43 SARs (AI </= 25%) and eight RARs (AI >/= 50%). Inhalation of furosemide (n = 29) increased the slope of airway pressure (Paw) versus sf of SARs from 8.6 to 14.8 Hz/cm H(2)O with an increase in sf at Paw = 0 cm H(2)O from 18.0 to 49.5 Hz, resulting in an upward shift of the line. Neither inhalation of vehicle (n = 9) nor intravenous injection of furosemide (n = 5) changed this relationship. In addition, inhalation of furosemide attenuated the activity of RARs. These findings indicate that SARs are sensitized and RARs desensitized by inhalation of furosemide. We discuss possible mechanisms for this, and its relevance to clinical problems of dyspnea, bronchoconstriction, and cough.

Annexin XI may be involved in Ca2+ - or GTP-gammaS-induced insulin secretion in the pancreatic beta-cell

The aim of this study was to investigate possible involvement of annexin XI in the insulin secretory machinery. In fluorescence immunocytochemistry, annexin XI was found in the cytoplasm of pancreatic endocrine cells and a pancreatic beta-cell line, MIN6, in a granular pattern. MIN6 cells also possessed weak and diffused annexin XI immunoreactivity in the cytoplasm. Immunoelectron microscopy revealed annexin XI in the insulin granules. Insulin secretion from streptolysin-O-permeabilized MIN6 cells was inhibited by anti-annexin XI antibody, when the release was stimulated by either Ca2+ or GTP-gammaS, but not by a protein kinase C-activating phorbol ester. Inhibition of insulin release by anti-annexin XI antibody was reproduced in permeabilized rat islets. These findings suggest that annexin XI may be involved in the regulation of insulin secretion from the pancreatic beta-cells.