Relationship between EEG dimensional complexity and neuropsychological findings in Alzheimer's disease

The aim of the present study was to examine the region-specific correlations between electroencephalography (EEG) dimensional complexity (DC), a measure of non-linear dynamics, and neuropsychological performance in 25 right-handed patients with Alzheimer's disease (AD). Electroencephalography recording sites were according to the international 10-20 system. Neuropsychological tests included Wechelor Adult Intelligence Scale-Revised (WAIS-R) (Full-scale Intelligence Quotient (FIQ), Verbal Intelligence Quotient (VIQ), Performance Intelligent Quotient (PIQ)); Mini-Mental State Examination; Raven's Coloured Progressive Matrices (RCPM); Rey Auditory-Verbal Learning Test (RAVLT); seven word pairs-revised Miyake Paired-Associate Word Learning Test; Benton Visual Retention Test; and Rey Complex Figure Test. A partial correlational analysis was carried out, controlling for age and sex (P< 0.005). The FIQ, VIQ and RCPM scores were found to be significantly correlated with DC at the F3, C3 and T3 electrodes. Significant correlations were also found between RAVLT scores and DC at the C3, P3 and T5 electrodes. The study on AD indicated region-specific correlations between DC and neuropsychological performance: one between the DC value in the left frontal, central and mid-temporal areas and intellectual function; and another between the DC value in the left central, parietal and post-temporal areas and verbal memory. Dimensional complexity would therefore seem to be a useful indicator for the assessment of neuropsychological deficits in AD.

Identification and characterization of human Wee1B, a new member of the Wee1 family of Cdk-inhibitory kinases

BACKGROUND

In eukaryotic cells, the kinase activity of the mitosis-promoting complex composed of cyclin B and Cdc2 (Cdk1) is negatively regulated by the phosphorylation of Cdk1 on threonine or tyrosine residues within its ATP binding domain.

RESULTS

We identified human Wee1B by searching a sequence database. The predicted human Wee1B protein comprises 561 amino acids. Northern blot analysis revealed that human Wee1B mRNA is particularly abundant in testis. Interestingly, RT-PCR using early embryos revealed that the Wee1B product was readily detectable at the mature oocyte, but abruptly disappeared at embryonic day 2.5, suggesting that the amount of Wee1B mRNA is dependent on the maternal expression. GFP-Wee1B showed a predominantly nuclear localization in HeLa cells. Human Wee1B was able to rescue the lethal phenotype of the fission yeast wee1-50Deltamik1 mutant, and over-expression of the human protein in these cells resulted in cell elongation as a result of arrest of the cell cycle at the G2-M transition. Recombinant Wee1B effectively phosphorylated cyclin B-associated Cdk1 on tyrosine-15, resulting in an inactivation of the kinase activity of Cdk1.

CONCLUSION

We identified human Wee1B as a novel Cdk1-inhibitory kinase. The identification of this new member of the Wee1 family suggests that inhibition of Cdk1 is mediated at multiple levels in mammals.

The binding site of transcription factor YY1 is required for intramolecular recombination between terminally repeated sequences of linear replicative hepatitis B virus DNA

In the replication cycle of hepadnavirus DNA, the double-stranded linear form of viral DNA is generated as a minor replicative intermediate, which is efficiently converted to covalently closed circular DNA (cccDNA) by intramolecular recombination (W. Yang and J. Summers, J. Virol. 69:4029-4036, 1995). We previously found a binding site of transcription factor Yin and Yang 1 (YY1) in one terminal region of the double-stranded linear replicative hepatitis B virus (HBV) DNA (M. Nakanishi-Matsui, Y. Hayashi, Y. Kitamura, and K. Koike, J. Virol. 74:5562-5568, 2000). However, it is not known whether the YY1-binding site is required for the intramolecular recombination of HBV DNA. In this study, we established an HBV-producing system in which the cccDNA appeared to be generated from the transfected linear DNA or the linear replicative DNA by nonhomologous end joining (NHEJ) or by both NHEJ and homologous recombination between terminally repeated sequences, respectively. When the YY1-binding site in the terminal region of transfected linear viral DNA was mutated, the cccDNA was generated merely by NHEJ. Results suggest that the YY1-binding site in the terminal region of linear replicative HBV DNA is required for intramolecular recombination between terminally repeated sequences.

Gene transfection activities of amphiphilic steroid-polyamine conjugates

The design and evaluation of a novel potent class of DNA delivery agents based on steroid-polyamine conjugates bearing a flexible linker are reported. The hydrophobic regions are based on steroids, i.e. chlolestane and lithocholic acid motifs. The linker, which couples a hydrophobic steroid and a hydrophilic polyamine, in this study can be regarded as a two-atom extension of the conventional carbamate linker. We found that the gene transfection activity of the steroid-polyamine conjugates is influenced by the polyamine chain length and steroid structure. Molecular modeling of the relevant amphiphilic molecules revealed low-energy structures in which the polyamine chains are folded rather than stretched. This work suggests a significant effect of space-filling, i.e. the shape and orientation of the hydrophilic and hydrophobic regions, upon the efficiency of gene transfection.

Facilitatory roles of novel compounds designed from cyclopentenone prostaglandins on neurite outgrowth-promoting activities of nerve growth factor

Cyclopentenone prostaglandins (PGs) are known to arrest the cell cycle at the G(1) phase in vitro and to suppress tumor growth in vivo. However, their effects on neurons are unclear. Here, we report that some cyclopentenone PGs function as neurite outgrowth-promoting factors. They promoted neurite outgrowth from PC12 cells and from dorsal root ganglion explants but only in the presence of nerve growth factor (NGF). We refer to these PGs as neurite outgrowth-promoting PGs (NEPPs). Through study of the structure-function relationship of NEPP1-10 and related compounds, we found that the cross-conjugated dienone moiety of NEPPs was essential for promoting neurite outgrowth, and NEPP10 was concluded to be the best candidate for drug development. We also investigated the intracellular mechanism of the promotion by NEPPs and obtained evidence that immunoglobulin heavy chain binding protein/glucose-regulated protein 78 (BiP/GRP78) plays a role in the promotion, based on the following observations: Antisense nucleotides for BiP/GRP78 gene blocked the promotion of neurite outgrowth; BiP/GRP78 protein level increased in response to NEPPs; and overexpression of BiP/GRP78 protein by adenoviral gene transfer promoted the neurite outgrowth by NGF.

Intracelluar dynamics of a high affinity NGF receptor TrkA in PC12 cell

A high affinity nerve growth factor (NGF) receptor, tropomyosin-receptor kinase (TrkA), is visualized by expression of TrkA conjugated with cyan fluorescent protein (CFP) in PC12 cells. TrkA was distributed on the plasma membrane of PC12 cells almost uniformly in both differentiated cells and undifferentiated cells. NGF induced differentiation of PC12 cells transfected with TrkA-CFP normally as wild cells without transfection and the expression of TrkA was observed on the entire cell membrane which surrounds the cell body, axons and growth cones. Interestingly, TrkA-CFP was also present on the membrane of filopodia sticking out from the axon and growth cone. In the axonal region, transporting vesicles of TrkA with diameters ranging from 0.5 to 1.5 microm were observed. Some of these vesicles showed net directional movement along the axon in both directions, anterograde and retrograde. The mean velocity of anterograde and retrograde transport was 0.2+/-0.03 and 0.3+/-0.05 microm/s (mean+/-S.E.), respectively. Some vesicles moving anterogradely changed their direction occasionally although the net transport was anterograde. On the other hand, vesicles moving retrogradely seldom switched their direction in spite of occasional stops. These results demonstrated that the behavior of TrkA transporting vesicles in axons of PC12 cells was similar to that observed in the primary culture of sympathetic or sensory neuron. Therefore, it is suggested that the PC12 cell transfected with fluorescent protein-conjugated TrkA is a useful model for studying the signal transduction of NGF.

Leukotoxin, 9,10-epoxy-12-octadecenoate, causes pulmonary vasodilation by stimulation of vascular eNOS and iNOS

We have previously reported that leukotoxin, 9,10-epoxy-12-octadecenoate (Lx) dilates rat pulmonary arteries by means of nitric oxide synthase (NOS) activation. In this study, we investigated if Lx stimulates constitutive and/or inducible NOS. We studied the effect of the NOS inhibitors, N(G)-monomethyl-L-arginine and aminoguanidine, as well as endothelium denudation on Lx-induced rat pulmonary arterial dilation and that of aminoguanidine on Lx-induced endothelium denuded lipopolysaccharide (LPS)-treated rat pulmonary arterial dilation and tissue cGMP content. Furthermore, we assessed the effect of aminoguanidine, an inducible NOS (iNOS) inhibitor, on the cGMP content increase induced by Lx in LPS-treated human pulmonary artery smooth muscle cells (HPASMC). The NOS inhibitors and endothelium denudation significantly attenuated Lx-induced vasodilation. Aminoguanidine also significantly attenuated Lx-induced vasodilation in LPS-treated rat denuded pulmonary arteries, and attenuated Lx-induced cGMP content increase in denuded pulmonary arterial rings from LPS-treated rats and in LPS-treated HPASMC. These results suggest that Lx causes pulmonary vasodilation by stimulation of vascular endothelial NOS (eNOS) and iNOS.

Growth inhibition of human leukemia HL-60 cells by an antisense phosphodiester oligonucleotide encapsulated into fusogenic liposomes

We report here the antisense effect of phosphodiester oligodeoxynucleotide (D-ODN) using fusogenic liposomes (FL) as its carrier. FL has envelope proteins of the Sendai virus within its membrane and introduces its contents directly and efficiently into cytosol by means of the virus-cell fusion mechanism. Using antisense (AS) D-ODN 15-mer complementary to the c-myc proto-oncogene mRNA, including the translation initiation codon site, we analyzed the growth of HL-60 cells by [3H]-thymidine uptake. AS-ODNs encapsulated in FL inhibited the growth by about 70% that of the control HL-60 cells at 2.48 microM. In contrast, sense and scramble D-ODNs encapsulated in FL showed no effect of the growth of HL-60 cells at the same concentration. Even at 50 microM, free form D-ODNs did not show any effect. These results suggest that FL is potentially a useful delivery vehicle for oligonucleotide-based therapeutics, and that D-ODN may be a likely candidate for oligodeoxynucleotides when an efficient delivery system is used.

Validity of brief intelligence tests for patients with Alzheimer's disease

The validity of two kinds of brief intelligence tests for patients with Alzheimer's disease (AD) was investigated. In study 1, five short forms of the Japanese Wechsler Adult Intelligence Scale-Revised (JWAIS-R) were administered to 102 AD patients. The results showed that the intra-class correlation coefficients (ICC) between IQ estimated with the short forms and those obtained by administration of the full JWAIS-R were satisfactory, ranging from 0.82 to 0.98, and that the abbreviated forms took a shorter time to execute. In study 2, the Raven's Coloured Progressive Matrices (RCPM) and the Mini-Mental State Examination (MMSE) were administered to 67 AD patients. The ICC between the IQ estimated with these tests and the full-scale IQ of the JWAIS-R were both acceptable at 0.57, and each test could be carried out in a very short time. It was concluded that these brief tests, particularly the WAIS-R short forms, are highly practical for quick measurement of intelligence in AD patients, although they have their respective limitations.

Hormone binding induces rapid proteasome-mediated degradation of thyroid hormone receptors

The thyroid hormone 3,3',5-triiodo-l-thyronine (T3) is essential for growth, differentiation, and development. Its biological activities are mediated by T3 nuclear receptors (TRs). At present, how T3 regulates TR proteins and the resulting functional consequences are still unknown. Immunofluorescence analyses of endogenous TR in the growth hormone-producing GC cells showed that the T3-induced rapid degradation of TR was specifically blocked by lactacystin, a selective inhibitor of the ubiquitin-proteasome degradation pathway. Immunoblots demonstrated that the transfected TRbeta1 was ubiquitinated and that the ubiquitination was T3 independent. Studies with a series of truncated TRbeta1 showed that the hormone-binding domain was sufficient for the T3-induced rapid degradation of TRbeta1 by the proteasome degradation pathway. T3 also induced rapid degradation of TRbeta2 and TRalpha1. In contrast, the stability of the non-T3-binding TRalpha2 and naturally occurring TRbeta1 mutants that do not bind T3 was not affected by T3 treatment, indicating that hormone binding to receptor was essential for the degradation of the wild-type receptors. In the presence of proteasome protease inhibitors, the levels of both total and ubiquitinated TRbeta1 protein increased, yet T3-dependent transcriptional activation and the expression of the growth hormone gene were diminished, suggesting that proteasome-mediated degradation played a novel role in modulating transcriptional activation by TR. The present study reveals a role of T3 in modulating the functions of TR by regulating its receptor level via the ubiquitin-proteasome degradation pathway.

Simultaneous process of embossing and poling at elevated temperatures: a simple technique for nonlinear grating formation in polymer films

A simple technique for fabrication of nonlinear gratings in polymer films, based on simultaneous embossing and poling, is proposed and demonstrated. A master grating consisting of a metal electrode with a dielectric die was fabricated and used for repeated embossing of the grating structures into nonlinear optical polymers at elevated temperatures. At the same time, we applied high voltage to the polymer films to induce second-order nonlinearity. The grating profile and the nonlinearity were estimated, as well as the mass productivity of nonlinear gratings.

Amplification and over-expression of the AIB1 nuclear receptor co-activator gene in primary gastric cancers

Our analysis of chromosomal aberrations in primary gastric cancers using comparative genomic hybridization has revealed novel, high and frequent copy number increases in the long arm of chromosome 20, indicating that this region contains novel amplified genes involved in gastric cancer progression. AIB1, a member of the steroid receptor co-activator-1 family, has been cloned on 20q12 as a candidate target gene for this amplification in human breast cancers. In this study, we examined the numbers of AIB1 copies as well as their expression and relation to clinico-pathological features in 72 primary gastric cancers. AIB1 amplification was observed in 7% and over-expression in 40% of the specimens. AIB1 amplification always coincided with its over-expression, but several cases showed AIB1 over-expression without amplification, suggesting that expression of AIB1 is regulated not only by gene amplification but also by other mechanisms, such as transcriptional activation, in human gastric cancer. Gastric cancers with AIB1 amplification showed extensive lymph node metastases, liver metastases and poorer prognosis compared to those without amplification. Our results suggest that amplification and over-expression of AIB1 are likely to increase the number of malignant phenotypes of gastric cancers and that it can be expected to be useful as a marker of poor prognosis.

Synthesis of S-adenosyl-L-homocysteine hydrolase inhibitors and their biological activities

Several nucleosides have been prepared as a possible inhibitor of human S-adenosyl-L-homocysteine (SAH) hydrolase for the development of anti-viral agents. Recently, SAH hydrolase has been considered as an attractive target for parasite chemotherapy for malaria. We report synthesis of several nucleosides including carbocyclic nucleosides and their inhibitory activities against recombinant malaria and human SAH hydrolases.

Aberrant cell cycle checkpoint function and early embryonic death in Chk1(-/-) mice

The recent discovery of checkpoint kinases has suggested the conservation of checkpoint mechanisms between yeast and mammals. In yeast, the protein kinase Chk1 is thought to mediate signaling associated with the DNA damage checkpoint of the cell cycle. However, the function of Chk1 in mammals has remained unknown. Targeted disruption of Chk1 in mice showed that Chk1(-/-) embryos exhibit gross morphologic abnormalities in nuclei as early as the blastocyst stage. In culture, Chk1(-/-) blastocysts showed a severe defect in outgrowth of the inner cell mass and died of apoptosis. DNA replication block and DNA damage failed to arrest the cell cycle before initiation of mitosis in Chk1(-/-) embryos. These results may indicate that Chk1 is indispensable for cell proliferation and survival through maintaining the G(2) checkpoint in mammals.

Identification and characterization of cell lines with a defect in a post-adsorption stage of Sendai virus-mediated membrane fusion

In the early stage of infection, Sendai virus delivers its genome into the cytoplasm by fusing the viral envelope with the cell membrane. Although the adsorption of virus particles to cell surface receptors has been characterized in detail, the ensuing complex process that leads to the fusion between the lipid bilayers remains mostly obscure. In the present study, we identified and characterized cell lines with a defect in the Sendai virus-mediated membrane fusion, using fusion-mediated delivery of fragment A of diphtheria toxin as an index. These cells, persistently infected with the temperature-sensitive variant Sendai virus, had primary viral receptors indistinguishable in number and affinity from those of parental susceptible cells. However, they proved to be thoroughly defective in the Sendai virus-mediated membrane fusion. We also found that viral HN protein expressed in the defective cells was responsible for the interference with membrane fusion. These results suggested the presence of a previously uncharacterized, HN-dependent intermediate stage in the Sendai virus-mediated membrane fusion.

Mechanisms of antiapoptotic effects of estrogens in nigral dopaminergic neurons

Parkinson's disease is characterized by the mesencephalic dopaminergic neuronal loss, possibly by apoptosis, and the prevalence is higher in males than in females. The estrogen receptor (ER) subtype in the mesencephalon is exclusively ER beta, a recently cloned novel subtype. Bound with estradiol, it enhances gene transcription through the estrogen response element (ERE) or inhibits it through the activator protein-1 (AP-1) site. We demonstrated that 17beta-estradiol provided protection against nigral neuronal apoptosis caused by exposure to either bleomycin sulfate (BLM) or buthionine sulfoximine (BSO). BLM and BSO-induced nigral apoptosis was blocked by inhibitors for caspase-3 or c-Jun/AP-1. The antiapoptotic effect by estradiol was blocked by ICI 182,780, an antagonist for ER, but not by a synthesized peptide that inhibits binding of the ER to the ERE. Estradiol had no effects on caspase-3 activation and c-Jun NH(2)-terminal kinase (JNK), which were activated by BLM. It also suppressed apoptosis by serum deprivation, which was independent of caspase-3 activation. Therefore, the antiapoptotic neuroprotection by estradiol is mediated by transcription through AP-1 site downstream from JNK and caspase-3 activation. Furthermore, 17alpha-estradiol, a stereoisomer without female hormone activity, also provided an antiapoptotic effect. Therefore, the antiapoptotic effect is independent of female hormone activity.

The association of transforming growth factor-beta 1 with myometrial invasion of endometrial carcinomas through effects on matrix metalloproteinase

OBJECTIVE

The association of transforming growth factor-beta 1 (TGF-beta 1) with a matrix metalloproteinase (MMP) and a tissue inhibitor of metalloproteinase (TIMP), as well as myometrial invasion of endometrial cancer was studied.

METHODS

The effects of TGF-beta 1 on cellular invasiveness, gelatinase activity, and expression of TIMP-1 were examined in 2 endometrial adenocarcinoma cell lines, KLE and Ishikawa. Plasma was obtained from 8 endometrial cancer patients with Stage-Ia disease, from 6 with Stage-Ib disease, and from 4 with Stage-Ic disease, and the levels of TGF-beta 1 were measured by enzyme immunoassays. The immunohistochemical expression of MMP-9, TIMP-1, TGF-beta 1, and TGF-beta receptor Type I in tumor tissue from the same patients also was detected.

RESULTS

Invasiveness, gelatinase activity, and the expression of TIMP-1 were higher in KLE cells than in Ishikawa cells, and they were increased by treatment with rTGF-beta 1. The expression of TGF-beta receptor Type I was higher in KLE cells than in Ishikawa cells, which were unresponsive to exogenous TGF-beta 1. The plasma levels of TGF-beta 1 were greater in Stage-Ib and Stage-Ic patients than in Stage-Ia patients. MMP-9 and TGF-beta receptor Type I were expressed mainly in tumor cells, while TIMP-1 and TGF-beta 1 were localized in both tumor epithelial cells and stromal cells. MMP-9 and TIMP-1 were expressed only in Stage-Ib and Stage-Ic patients, although TGF-beta 1 and TGF-beta receptor Type I were ubiquitous.

CONCLUSIONS

Myometrial invasion of endometrial cancers involves an increase in gelatinase activity, regulated to some extent by TGF-beta 1 in an autocrine or paracrine fashion.

Monosialoganglioside containing cationic liposomes with a cationic cholesterol derivative promote the efficiency of gene transfection in mammalian culture cells

We have studied the effects of monosialoganglioside (GM1)-containing cationic liposomes with a cationic cholesterol on the liposome-mediated gene transfection into mammalian culture cells. The results showed that both cationic liposomes with either a cationic cholesterol derivative of a hydrophobic amino head group (I) and a hydrophilic amino head group (II) promoted the transfection of luciferase plasmids (pGL3) into HeLa and CHO-K1 cells more than the control cationic liposomes without GM1. In addition, we found that cationic liposomes with a cationic cholesterol derivative (II) were about ten times as effective as that by commercially available cationic liposome Lipofectin. Confocal fluorescence microscopy showed that the liposome/DNA complex was transferred more efficiently into the target cells by the GM1-containing liposomes than by the liposomes without GM1. In proportion to the above results, free antisense DNAs were also more efficiently transferred into the nucleus of the target cells by the GM1-containing liposomes. When there was 100 mM galactose in the transfection medium, the luciferase activity by the GM1-containing liposomes was reduced to the level of the control liposomes. The results suggest that GM1-containing cationic liposomes with a cationic cholesterol derivative of a hydrophobic amino head group or a hydrophilic amino head group should significantly increase the transfection efficiency of plasmid DNAs and antisense DNAs by galactose receptor-mediated endocytosis. This means that the GM1-containing liposomes described here should be very promising for gene transfection in vitro.

Atomic force microscopy to study the effects of ITIM-bearing FcgammaRIIB on the activation of RBL-2H3 cells

We have studied here the effects of ITIM-bearing FcgammaRIIB2 on the FcvarepsilonRI-dependent activation of rat basophilic leukemia (RBL-2H3) cells by atomic force microscopy (AFM). AFM images showed that ruffling and degranulation of RBL-2H3 cells were significantly reduced but the cell spreading was not by the co-clustering of FcgammaRIIB2 and FcvarepsilonRI. From the results it was shown that the co-clustering of ITIM-bearing negative co-receptors in a single RBL cell hardly induce the degranulation though the [Ca(2+)](i) increased transiently in the cell. This suggested that secretory responses and the membrane ruffling which were induced by the crosslinkng of FcgammaRII should be negatively controlled by the co-clustering of FcgammaRII.

Fusogenic liposomes efficiently deliver exogenous antigen through the cytoplasm into the MHC class I processing pathway

Exogenous soluble proteins enter the endosomal pathway by endocytosis and are presented in association with MHC class II rather than class I. In contrast, the delivery of exogenous protein antigens (Ag) into the cytosol generates MHC class I-restricted cytotoxic T lymphocytes (CTL) responses. Although several immunization approaches, such as the utilization of liposomes, have induced the in vivo priming of MHC class I-restricted CTL responses to protein Ag, it remains unclear whether this priming results from the direct delivery of protein Ag to the cytosol. Here we report that fusogenic liposomes (FL), which are prepared by fusing simple liposomes with Sendai virus particles, can deliver the encapsulated soluble protein directly into the cytosol of cells cultured concurrently and introduce it into the conventional MHC class I Ag presentation pathway. Moreover, a single immunization with ovalbumin (OVA) encapsulated in FL but not in simple liposomes results in the potent priming of OVA-specific CTL. Thus, FL function as an efficient tool for the delivery of CTL vaccines.

Induction of KAI-1 expression in metastatic cancer cells by phorbol esters

KAI-1 is a tumor suppressor gene whose down-regulation has been shown to be associated with the development of metastases of cancer cells. Here, we demonstrated that KAI-1 expression was induced by activating protein kinase C even in metastatic prostate cancer cell lines in which its expression was significantly down-regulated. KAI-1 expression was enhanced in a dose-dependent manner by PMA, and its induction is at least in part due to transcriptional activation. Pretreatment with calphostin C abrogated its induction by PMA. Our findings may provide useful information for developing a novel drug capable of inducing KAI-1 expression and thereby inhibiting metastasis.

Genomic alterations in primary gastric cancers analyzed by comparative genomic hybridization and clinicopathological factors

BACKGROUND/AIMS

Genetic changes during the oncogenesis and progression of gastric cancer remain unclear. The aim of our study was to analyze chromosomal aberrations in primary gastric cancers.

METHODOLOGY

Using comparative genomic hybridization, we screened 47 primary gastric cancers for changes in the number of copies of DNA sequences.

RESULTS

Gains of chromosome arms 20q (55%), 20p (36%), 17q (32%), 19q (30%) and 16p (30%), and losses of chromosome arms 4q (40%), 17p (40%), 5q (38%), 18q (30%) and 4p (28%) were detected most frequently. In addition, a high level of amplification was observed at 3q21 (2%), 6p21 (4%), 7q31 (6%), 8q23-24 (2%), 19q12-13 (2%), and 20q13 (2%). Among these alterations, the gain of 20q was the most frequent change. We then compared these changes with clinicopathological factors and identified signet ring cell carcinomas in 6 cases. Our study demonstrated no amplification of chromosome 20q in signet ring cell carcinoma in contrast to that in the other histologic types of gastric cancer.

CONCLUSIONS

Our findings may be related to the morphologic and clinical features of signet ring cell carcinoma, and several oncogenes mapped on 20q may play an important role as determinants of the clinical and histologic features of gastric cancer.

Rat basophilic leukemia cells express syntaxin-3 and VAMP-7 in granule membranes

In neuronal cells, it is generally agreed that SNARE proteins underlie the release of neurotransmitter. It is controversial, however, whether they also work functionally in the degranulation of RBL-2H3 cells because the expression of SNARE proteins has not been confirmed and the degranulation is not inhibited by tetanus toxin which cleaves one of SNARE proteins, VAMP-2. We investigated the expression and the localization of SNARE proteins including VAMP-7 which is insensitive to tetanus toxin. RT-PCR analysis showed the existence of SNARE proteins, including syntaxin-2, -3, -4, SNAP-23, VAMP-2, and VAMP-7. Experiments using GFP-conjugated proteins revealed that VAMP-7 was localized only in granule membranes, whereas syntaxin-3 was in both the plasma and granule membranes. Upon antigen stimulation, these proteins in granule membranes moved to the cell surface due to the fusion of granules with the plasma membrane. The results suggest the involvement of SNARE proteins in the degranulation of RBL-2H3 cells.

NAK is an IkappaB kinase-activating kinase

Phosphorylation of IkappaB by the IkappaB kinase (IKK) complex is a critical step leading to IkappaB degradation and activation of transcription factor NF-kappaB. The IKK complex contains two catalytic subunits, IKKalpha and IKKbeta, the latter being indispensable for NF-kappaB activation by pro-inflammatory cytokines. Although IKK is activated by phosphorylation of the IKKbeta activation loop, the physiological IKK kinases that mediate responses to extracellular stimuli remain obscure. Here we describe an IKK-related kinase, named NAK (NF-kappaB-activating kinase), that can activate IKK through direct phosphorylation. NAK induces IkappaB degradation and NF-kappaB activity through IKKbeta. Endogenous NAK is activated by phorbol ester tumour promoters and growth factors, whereas catalytically inactive NAK specifically inhibits activation of NF-kappaB by protein kinase C-epsilon (PKCepsilon). Thus, NAK is an IKK kinase that may mediate IKK and NF-kappaB activation in response to growth factors that stimulate PKCepsilon activity.

p27Kip1 expression by contact inhibition as a prognostic index of human glioma

The clinical manifestations of human glioma are known to be diverse, ranging from aggressive growth and invasion to apparent dormancy; however, the molecular mechanism underlying this diversity has been largely unexplored. In the present study, we characterized four human glioma cell lines, T98G, A172, U251, and NAC6, each of which has distinct growth properties. A172 and U251 cells continue to grow after confluency, whereas the growth of T98G and NAC6 cells is contact inhibited. Northern and western blot analyses revealed that at high cell density, the expression of p27Kip1 cyclin-dependent kinase inhibitor was dramatically enhanced at both the RNA and the protein levels in T98G and NAC6 cells but not in A172 or U251. These facts together with the finding that overexpression of p27Kip1 caused G1 arrest in A172 and T98G cells suggest that the induction of p27Kip1 represents an important determinant of growth at high cell density. Immunohistochemical analyses of 42 primary gliomas revealed an inverse correlation between the level of p27 protein and the Ki-67 proliferative index. Kaplan-Meier plots demonstrated that a low level of p27 in tumors is associated with decreased overall survival. Thus, disrupted regulation of p27 expression at high cell density may play an important role in determining the clinical behavior of human gliomas as well as the prognosis for glioma patients.

Development of a kinetic assay for band 5b tartrate-resistant acid phosphatase activity in serum

BACKGROUND

Band 5 tartrate-resistant acid phosphatase (TrACP; EC 3. 1.3.2) consists of two isoenzymes, bands 5a and 5b, of which band 5b TrACP is considered to be derived from bone. However, no kinetic method for the specific measurement of band 5b TrACP in serum is available. Our aim was to develop a kinetic assay method for the specific measurement of band 5b TrACP in serum.

METHODS

Band 5b TrACP was measured kinetically in serum as tartrate-resistant fluoride-sensitive heparin-resistant ACP with 2, 6-dichloro-4-acetylphenyl phosphate as substrate at pH 6.6.

RESULTS

Heparin inhibited band 5a TrACP but had no effect on band 5b TrACP in serum or in bone extract. The presence of EDTA or ascorbic acid had no effect, but dithiothreitol inhibited enzyme activity. The within-run (n = 20) and between-run (n = 20) CVs of band 5b TrACP activity were 3.3-5.8% and 5.0-7.3%, respectively. The mean +/- SD values of band 5b TrACP activity in males (n = 25) and females (n = 57) 20-29 years of age by this method were 8.0 +/- 2.2 U/L and 6.4 +/- 1.8 U/L, respectively. The band 5b TrACP value was significantly higher in females >50 years of age compared with the younger subjects (20-29 years). The highest band 5b TrACP values were among children younger than 15 years.

CONCLUSIONS

This kinetic assay is a simple and specific method for the measurement of band 5b TrACP in serum samples and is useful in the evaluation of bone turnover activity.

Semantic priming in patients with Alzheimer and semantic dementia

Semantic priming for pairs of words having semantic relation (members of the same category) but not associative relation was tested in four patients with mild Alzheimer-type dementia (AD), three patients with semantic dementia (SD) and three normal controls. Priming effects were exhibited by all the AD patients and normal controls but by none of the SD patients. The facilitation did not differ depending on whether words were written in kanji or kana. The nature of semantic deficits in AD and SD is discussed.

Neuroprotective mechanism of glial cell line-derived neurotrophic factor in mesencephalic neurons

Glial cell line-derived neurotrophic factor (GDNF) provides neuroprotection, but its neuroprotective mechanism has not been resolved. We investigated the neuroprotective mechanism of GDNF using primary culture of the rat mesencephalon. Bleomycin sulfate (BLM) and L-buthionine-[S,R]-sulfoximine (BSO) caused apoptosis in both dopaminergic and nondopaminergic neurons, as revealed by the presence of chromatin condensation, and positive staining by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end-labeling (TUNEL). GDNF preincubation blocked the neurotoxicity and reduced the number of the TUNEL-positive cells caused by BLM and BSO exposure. In contrast, GDNF did not provide neuroprotection against glutamate toxicity, which was not accompanied by these apoptotic features. The neuroprotection was mediated by phosphatidylinositol 3-kinase, an effector downstream from c-Ret, because it was blocked by LY294002. GDNF pretreatment caused up-regulation of Bcl-2 and Bcl-x. Furthermore, GDNF suppressed oxygen radical accumulation caused by BLM. Apoptosis induced by BLM and BSO was blocked by a caspase-3 inhibitor. Caspase-3 activity was elevated by BLM and suppressed by GDNF pretreatment. These findings indicate that GDNF has no effect on necrosis but exerts protection against apoptosis by activation of phosphatidylinositol 3-kinase and the subsequent up-regulation of Bcl-2 and Bcl-x, which suppresses accumulation of oxygen radicals followed by caspase-3 activation.

[Two cases of lung metastasis of malignant melanoma]

We report 2 cases of lung metastasis of malignant melanoma. Patient 1 was a 71-year-old woman who had undergone an operation for enucleation of her left eye 13 years earlier. Chest magnetic resonance imaging (MRI) demonstrated intermediate intensity including partially high intensity on T 1 weighted images, and high intensity including partially low intensity on T 2 weighted images. Microscopic findings from a transbronchial lung biopsy specimen disclosed melanotic melanoma. Patient 2 was a 54-year-old man who had undergone surgery for malignant melanoma in the left upper arm 4 years earlier. Chest MRI films demonstrated low intensity on T 1 weighted images, and high intensity on T 2 weighted images. Microscopic findings from specimens of the primary lesion in the left upper arm revealed melanotic melanoma, but the findings from the lower right lobectomy disclosed amelanotic melanoma. It has been reported that MRI is useful in the diagnosis of malignant melanoma, and that melanin content reflects MRI signal intensity. The MRI findings were consistent with the histopathologic findings in each of the 2 cases we reported.

Cdk4 activation is dependent on the subunit rearrangement in the complexes

Although several factors have been implicated in the regulation of Cdk4 activity, little is known regarding the contributions of cyclin-dependent kinase inhibitors (CKIs) in Cdk4 activation in the mid G1 phase. Using a mouse macrophage cell line (Bac1.2F5), we found that most of Cdk4 bound to p15 when cells were in a quiescent state. Following CSF-1 stimulation, Cdk4 bound to cyclin D1 and then to p21, concomitant with the dissociation of p15 from the complexes. The activation of Cdk4 correlated well with p21 binding to the complexes, and the majority of active Cdk4 complexes contained p21. During regeneration of mouse liver after partial hepatectomy, Cdk4 activity coincided precisely with ternary complex formation of cyclin D1/Cdk4/p21. Using the baculovirus expression system, we succeeded in reconstituting a capacity for Cdk4 activation in insect cells, forming an active cyclin D1/Cdk4/p21 ternary complex. Taken together, it is suggested that p21 and cyclin D1 act cooperatively as activators of Cdk4 through the release of CKIs of the INK4 family.

Aberrant expression of p27(Kip1) is associated with malignant transformation of the rat urinary bladder epithelium

Alteration in cell cycle regulators is considered to play an important role in carcinogenesis. In order to cast light on changes in reversible hyperplastic and irreversible tumorigenic lesions in the rat urinary bladder, expression of p27(Kip1), cyclin D1 and cyclin E proteins was sequentially compared. In the first study, 3% uracil was fed for 4 weeks to cause urinary calculi and consequent hyperplasia and papillomatosis, both regressing after withdrawal of the insult. Compared with normal bladder epithelium, in papillomatosis at week 4, the BrdU index and immunohistochemical positivities for cyclin D1 and cyclin E were significantly elevated, whereas values for p27(Kip1) tended to be reduced. One week after withdrawal of uracil, the BrdU index and positivities for cyclin D1 and cyclin E were decreased to below the control levels, while positivity for p27(Kip1) was dramatically increased, with a strong staining intensity. In a second study, rats were initiated with a bladder carcinogen, N-butyl-N-(4-hydroxybutyl)nitrosamine for 4 weeks, then fed 3% uracil for 8 weeks. During this latter period, expression of cyclin D1, cyclin E and p27(Kip1) in hyperplastic urothelium were comparable with those in the first study. One week after withdrawal of uracil, most urothelial lesions regressed, showing high p27(Kip1) and low cyclin D1 and cyclin E staining. Two weeks after uracil withdrawal, transitional cell carcinomas, with a low p27(Kip1) and high cyclin D1 and cyclin E staining pattern, could be easily distinguished from surrounding regressing epithelium. These data indicate that during regression of papillomatosis after cessation of a proliferative stimulus, expression of p27(Kip1)is elevated, accompanied by a lowering of cyclin D1 and cyclin E. In irreversible tumorous bladder lesions, on the other hand, persistent low expression of p27(Kip1) and elevated cyclin D1 and cyclin E are characteristic.

On using the CAM concept for parametric curve extraction

In this correspondence, a parallel algorithm, in order to extract parametric curves from a two-dimensional (2-D) image space, is proposed. It is based on the Hough transform (HT) and uses the content addressable memory (CAM) as the main processor. A set of simulated results for circular shape extraction are presented in order to demonstrate its merit. Hence, voting, thresholding, and three-dimensional (3-D) peak extraction are efficiently performed within the CAM. In addition, and in order to reduce the quantization errors, a weighted AT algorithm (WHT), which uses a weighted voting is proposed. Experimental results indicate that a real-time shape extraction for an image 256/spl times/256 can be achieved within a small amount of hardware. Therefore, CAM-based HT can be considered as a promising attraction for next generation pattern recognition platforms.

Transforming growth factor-beta1 stimulates contraction of human glioblastoma cell-mediated collagen lattice through enhanced alpha2 integrin expression

Rapid invasiveness is a feature of the highly malignant glioblastoma tumor and is closely related to patient prognosis. The interaction between extracellular matrix (ECM) and cell surface receptors such as integrin heterodimers play a key role in the process of tumor invasion. We investigated the effects of transforming growth factor-beta1 (TGF-beta1), which is a mitogenic factor for glial cells, on integrin expression in T98G human glioblastoma cells using an in vitro model 3-dimensional collagen lattice. Exogenously applied TGF-beta1 dose-dependently enhanced collagen lattice contraction. Among the inhibitory antibodies tested against alpha integrin subunits, the anti-alpha2 antibody, P1-E6, alone prevented the enhanced contractile response by TGF-beta1, whereas any alpha integrin antibody (including P1-E6) had little effect on lattice contraction when cultured without TGF-beta1. RT-PCR analysis revealed that TGF-beta1 strongly increased alpha2 integrin transcript level. Furthermore, pretreatment with antisense phosphorothioate oligodeoxynucleotides against human alpha2 integrin using hemagglutinating virus of Japan (HVJ) liposome-mediated transfer prevented the effects of TGF-beta1 and also reduced the lattice contraction even in the absence of TGF-beta1. This data indicates that increased expression of alpha2 integrin is responsive to enhanced collagen lattice contraction by TGF-beta1. We suggest that TGF-beta1 exerts its effects on the invasive property of glioblastoma cells via upregulation of the alpha2 integrin subunit expression.

Complex mechanisms underlying impaired activation of Cdk4 and Cdk2 in replicative senescence: roles of p16, p21, and cyclin D1

Numerous changes in gene expression are known to occur during replicative senescence, including changes in genes involved in the cell cycle control. In the present study, we have found a severe impairment in the activation of Cdk2 and Cdk4 in response to mitogens in senescent human fibroblasts and determined the molecular basis for this. Although Cdk4 protein was constitutively expressed in senescent cells at the same level as in early-passage young cells, it was found to be complexed with a distinct set of Cdk inhibitors. Cdk4 derived from early passage quiescent cells was effectively activated by incubation with cyclin D1 and Cdk-activating kinase (CAK) in vitro, whereas Cdk4 from senescent cells was not. Cdk2 protein was dramatically decreased in senescent cells and complexed primarily with cyclin D1 and p21. This cyclin D1-bound Cdk2 was not activated by CAK either in vivo or in vitro, implicating cyclin D1 as an inhibitor of Cdk2 activation. Thus, one of the underlying molecular events involved in replicative senescence is the impaired activation of Cdk4 and Cdk2 due to increased binding of p16 to Cdk4 and increased association of Cdk2 with cyclin D1 and p21.

A novel human gene encoding HECT domain and RCC1-like repeats interacts with cyclins and is potentially regulated by the tumor suppressor proteins

Cyclin E-Cdk2 is an evolutionary conserved cyclin-dependent kinase (CDK) complex that drives the G1 to S phase transition of the cell cycle. A novel cDNA encoding a HECT family protein also containing RCC1-like repeats was isolated by a yeast two-hybrid screening using both cyclin E and its inhibitor p21. The protein product of this cDNA, Ceb1, interacts with various cyclin subunits of CDKs in mammalian cells. Expression of Ceb1 is specifically detected in testis and ovary and is highly elevated when the functions of the tumor suppressor proteins, p53 and RB, are compromised by mutations or viral oncoproteins. The present results suggest that Ceb1 may play a critical role when its expression and the CDK activity are upregulated by inactivation of p53 and RB.

Phorbol ester inhibits DNA damage-induced apoptosis in U937 cells through activation of protein kinase C

The effects of phorbol 12-myristate 13-acetate (PMA) on DNA damage-induced apoptosis were examined in promyelocytic leukemia cells, U937, in comparison with other differentiation-inducing agents to clarify the role of protein kinase C (PKC) vis-a-vis cellular differentiation in apoptosis. The apoptosis of U937 cells was observed at as early as 1-1.5 h following UV irradiation, with most cells being in apoptotic state at 3 h. Pretreatment with PMA for as short as 5 min was sufficient to inhibit apoptosis induced by UV irradiation, whereas apparent changes in cell cycle distributions and expression of differentiation markers by PMA were not observed until 12 h and 48 h, respectively. The inhibition of apoptosis by PMA was completely abolished by the pretreatment with calphostin C, a PKC inhibitor, and 4 alpha-phorbor 12,13-didecanoate, which is unable to activate PKC, did not protect U937 cells against apoptosis induced by UV irradiation. Other differentiation inducers, such as cyclic AMP and active vitamin D3, did not affect the UV-induced apoptosis of U937 cells. Taken together, it was suggested that PMA inhibits DNA damage-induced apoptosis through the activation of PKC rather than as a result of differentiation of U937 cells.

Bowel perforation during chemotherapy for non-hodgkin's lymphoma

Bowel perforation in patients with primary malignant lymphoma usually occurs at the site of tumor. A 78 year-old man underwent chemotherapy for malignant lymphoma. He presented with abdominal pain. An emergency operation was performed under a diagnosis of panperitonitis. At laparotomy, an anal-side perforation approximately 20 cm from the Treiz ligament was observed. Drainage and partial resection of the jejunum was performed. Histopathologic examination demonstrated that there was no characteristic finding of malignant lymphoma around the perforation site in the case. Perforation of the small intestine is one of the most critical complications during the chemotherapy for malignant lymphoma. In cases of chemotherapy for malignant lymphoma, especially systemic administration, we should keep in mind the possibility of perforation of the small intestine. Fortunately, emergency surgery saved the patient presented in this report. Early diagnosis and treatment are important to improve prognosis of bowel perforation in patients with primary malignant lymphoma.

Role of human Cds1 (Chk2) kinase in DNA damage checkpoint and its regulation by p53

In response to DNA damage, mammalian cells adopt checkpoint regulation, by phosphorylation and stabilization of p53, to delay cell cycle progression. However, most cancer cells that lack functional p53 retain an unknown checkpoint mechanism(s) by which cells are arrested at the G(2)/M phase. Here we demonstrate that a human homolog of Cds1/Rad53 kinase (hCds1) is rapidly phosphorylated and activated in response to DNA damage not only in normal cells but in cancer cells lacking functional p53. A survey of various cancer cell lines revealed that the expression level of hCds1 mRNA is inversely related to the presence of functional p53. In addition, transfection of normal human fibroblasts with SV40 T antigen or human papilloma viruses E6 or E7 causes a marked induction of hCds1 mRNA, and the introduction of functional p53 into SV40 T antigen- and E6-, but not E7-, transfected cells decreases the hCds1 level, suggesting that p53 negatively regulates the expression of hCds1. In cells without functional ataxia telangiectasia mutated (ATM) protein, phosphorylation and activation of hCds1 were observed in response to DNA damage induced by UV but not by ionizing irradiation. These results suggest that hCds1 is activated through an ATM-dependent as well as -independent pathway and that it may complement the function of p53 in DNA damage checkpoints in mammalian cells.

Characterization of the human dihydropyrimidinase-related protein 2 (DRP-2) gene

The genes within the dihydropyrimidinase-related protein (DRP) family, were originally identified in humans by their homology to dihydropyrimidinase (DHP). Four members of this gene family, DRP-1, -2, -3 and -4, are expressed mainly in the fetal and neonatal brains of mammals and chickens, and have been implicated as intracellular signal transducers in the development of the nervous system. We isolated the human DRP-2 gene, and determined its transcriptional start site and exon/intron organization. The gene spanned more than 62 kb, and contained 14 exons with lengths ranging from 62 bp to 2606 bp. The transcriptional start site was determined by an RNase protection assay and 5' rapid amplification of cDNA ends (RACE), and a highly GC-rich promoter was identified that contained possible regulatory elements such as a TATA box, CAAT box and three GC boxes. Comparison of the phase and position of intron insertions within the human DRP-2 gene with those within DRP-1, DHP and two Caenorhabditis elegans DRP/DHP homologs, indicated that DRPs are more conserved in their exon/intron organization than DHP.

Helicobacter pylori and mucosal atrophy in patients with gastric cancer: a special study regarding the methods for detecting Helicobacter pylori

We assessed the sensitivities of several methods for detecting Helicobacter pylori (culture, histology, rapid urease test, and serology), and evaluated the H. pylori positivity considering the degree of atrophy in the background mucosa in 202 gastric cancer patients and 101 controls. The positivity of H. pylori determined by culture (81%) was significantly higher than that determined by serology (62%) in gastric cancer patients (P < 0.001). The positivities of H. pylori determined by biopsy and/or serology in intestinal (84%) and diffuse (95%) types of gastric cancer were higher than that observed in controls (54%) (P < 0.001). Intestinal-type gastric cancer tended to occur in the atrophic mucosa, in which H. pylori positivity was not different from that in controls after adjusting for the degree of atrophy, whereas diffuse-type gastric cancer was observed more often in the nonatrophic mucosa, in which H. pylori positivity was higher than that in controls even after adjusting for the degree of atrophy.

9-[(2'S,3'S)-3'-formyl-2',3'-dihydroxypropyl]adenine: a facile affinity-labeling probe of human S-adenosyl-L-homocysteine hydrolase

Treatment of human recombinant S-adenosyl-L-homocysteine (SAH) hydrolase with 9-[(2'S,3'S)-3'-formyl-2',3'-dihydroxypropyl]adenine (FDHPA) caused irreversible inactivation in a time- and concentration-dependent manner (Ki = 8.8 microM, k(inact) = 0.09 min(-1)). FDHPA behaved as a facile affinity-labeling probe of SAH hydrolase.

Direct interaction of p21 cyclin-dependent kinase inhibitor with the retinoblastoma tumor suppressor protein

The p21CKI forms a physical complex with the retinoblastoma protein (pRb) both in vitro and in vivo. The A/B pocket region of pRb and the N-terminal region of p21 were indispensable for this interaction. Among p21 family members, p57, but not p27, associated with pRb. Overexpression of cyclin D1, Cdk4, and E2F1 in the cells expressing pRb and p21 did not perturb the interaction between p21 and pRb. Coexpression of p21 in cells expressing pRb, cyclin D1, and Cdk4 prevented pRb hyperphosphorylation by cyclin D1/Cdk4. On the other hand, hyperphosphorylation of pRb by an excess amount of cyclin/Cdk disrupted pRb/p21 complex formation in vitro. These findings suggest that pRb may be dynamically regulated by the relative binding and activities of p21 and Cdks.

Direct neurite-mast cell communication in vitro occurs via the neuropeptide substance P

Communication between nerves and mast cells is a prototypic demonstration of neuroimmune interaction. However, whether mast cell activation occurs as a direct response to neuronal activation or requires an intermediary cell is unclear. Addressing this issue, we used an in vitro coculture approach comprising cultured murine superior cervical ganglia and rat leukemia basophilic cells (RBLs; possesses properties of mucosal-type mast cells). Following loading with the calcium fluorophore, Fluo-3, neurite-RBL units (separated by <50 nm) were examined by confocal laser scanning microscopy. Addition of bradykinin, or scorpion venom, dose-dependently elicited neurite activation (i.e., Ca2+ mobilization) and, after a lag period, RBL Ca2+ mobilization. Neither bradykinin nor scorpion venom had any direct effect on the RBLs in the absence of neurites. Addition of a neutralizing substance P Ab or a neurokinin (NK)-1 receptor antagonist, but not an NK-2 receptor antagonist, dose-dependently prevented the RBL activation that resulted as a consequence of neural activation by either bradykinin or scorpion venom. These data illustrate that nerve-mast cell cross-talk can occur in the absence of an intermediary transducing cell and that the neuropeptide substance P, operating via NK-1 receptors, is an important mediator of this communication. Our findings have implications for the neuroimmune signaling cascades that are likely to occur during airways inflammation, intestinal hypersensitivity, and other conditions in which mast cells feature.

Atomic force microscopy to study the degranulation in rat peritoneal mast cells after activation

We have studied the degranulation in rat peritoneal mast cells by atomic force microscopy (AFM). Although AFM has advantages close to electron microscopy (EM) in spatial resolution, visualization of surface topography in peritoneal mast cells has not been reported yet. In the present paper we have succeeded in visualizing the degranulation process of rat peritoneal mast cells by AFM. AFM images showed that secretory granules were about 1 microm in diameter and that they were densely packed in the cytoplasm surrounding the nucleus. After stimulation with compound 48/80 (5 microg/ml), the packed granules began to loosen through formation of irregular cracks, as if polymerization of actin filaments was changed; 3 min after stimulation with compound 48/80 at 37 degrees C, the packed granules were completely loosened and the nucleus was no longer covered by the granules. In addition, AFM images showed clear fringes at the edges of the spreading cells. The fringes were 30-50 nm in height and there existed many small matrixes which were secreted to the outside of the cell. The matrixes were about 80 nm in diameter and 40 nm in height. These kinds of secretory matrixes were observed here first by AFM.

Direct Neurite-Mast Cell Communication In Vitro Occurs Via the Neuropeptide Substance P

Communication between nerves and mast cells is a prototypic demonstration of neuroimmune interaction. However, whether mast cell activation occurs as a direct response to neuronal activation or requires an intermediary cell is unclear. Addressing this issue, we used an in vitro coculture approach comprising cultured murine superior cervical ganglia and rat leukemia basophilic cells (RBLs; possesses properties of mucosal-type mast cells). Following loading with the calcium fluorophore, Fluo-3, neurite-RBL units (separated by &lt;50 nm) were examined by confocal laser scanning microscopy. Addition of bradykinin, or scorpion venom, dose-dependently elicited neurite activation (i.e., Ca2+ mobilization) and, after a lag period, RBL Ca2+ mobilization. Neither bradykinin nor scorpion venom had any direct effect on the RBLs in the absence of neurites. Addition of a neutralizing substance P Ab or a neurokinin (NK)-1 receptor antagonist, but not an NK-2 receptor antagonist, dose-dependently prevented the RBL activation that resulted as a consequence of neural activation by either bradykinin or scorpion venom. These data illustrate that nerve-mast cell cross-talk can occur in the absence of an intermediary transducing cell and that the neuropeptide substance P, operating via NK-1 receptors, is an important mediator of this communication. Our findings have implications for the neuroimmune signaling cascades that are likely to occur during airways inflammation, intestinal hypersensitivity, and other conditions in which mast cells feature.

Infrequent activation of mitogen-activated protein kinase in human colon cancers

BACKGROUND/AIMS

Mitogen-activated protein kinase (MAPK) is a downstream factor of the Ras-Raf-MAPK cascade and it is now considered to be a key molecule in signaling processes stimulated by growth factors and differentiation inducers.

METHODOLOGY

We examined MAPK activity in 21 advanced colon cancers to investigate whether the MAPK cascade might play a role in the progression of colon cancers.

RESULTS

MAPK activation (3.9-10.1-fold) was observed in 4 of 21 cases (18%), but 3 cases (75%, 3 of 4 cases) showed MAPK activation without ras mutation, thus suggesting that MAPK activation did not correlate with the presence of Ki-ras mutations in these cases. Other kinds of oncogene activation would be involved to MAPK activation in human colon cancers. In other cases MAPK activation was not detected or partly down-regulated.

CONCLUSIONS

These findings suggest that positive and negative regulation of MAPK activity are associated with loss of normal growth control and may be involved in carcinogenesis of colon cancers.