Optical detection of dendritic spike initiation in hippocampal CA1 pyramidal neurons

Previous studies have shown that spikes can be generated in the dendrites of CA1 pyramidal neurons. Some have suggested that, in response to synaptic inputs, spikes are initiated near the soma and propagate back into the dendrites, but some recent studies have shown that intense synaptic inputs initiate spikes in the dendrite. Here, we report the optical detection of spike propagation along the apical dendrites of hippocampal pyramidal neurons. Rat hippocampal slices were stained with the fluorescent voltage-sensitive dye, JPW1114, and optical signals monitored using a 16 x 16 photodiode array system at a frame rate of 4 kHz. A stimulating electrode was placed at the boundary between the stratum (str.) lacnosum-moleculare and the str. radiatum to stimulate the Schaffer collateral, and fast and slow signal components were detected in the dendritic and somatic regions. By comparing the optical signals with whole-cell recordings, we confirmed that the fast component was due to a population of dendritic spikes in pyramidal neurons. The fast component appeared in dendritic locations near the input sites in response to synaptic activation, and signal onset at the soma was delayed by a few milliseconds compared with that at the input sites. Local perfusion of a Na(+) channel blocker near the soma eliminated the fast component at the soma, but had no effect on the fast component at the input sites. Our results indicate that dendritic spikes can be initiated in dendrites near the input site and propagate orthodromically toward the proximal dendrites and the soma.

Inhibition of CD44v9 upregulates the invasion ability of oral squamous cell carcinoma cells

The aim of the present study has been to determine the role of CD44v9 in the metastatic process of oral squamous cell carcinoma (OSCC). We have examined the expression intensity of CD44v9 in four OSCC cell lines, and using cell culture insert investigated the invasion ability of the cells expressing CD44v9 at higher levels (HSC-2, HSC-3), and the cells expressing this protein at lower levels (HSC-4, KB) with or without the treatment with an anti-CD44v9 antibody. In the highly expressing cells, the addition of anti-CD44v9 antibody enhanced their invasion ability, whereas it showed no effect on the invasion ability of the weakly expressing cells. These results suggest that the reduction of CD44v9 expression may weaken cell-to-cell adhesion in OSCC and make the tumor cells detach easily from their nests, resulting in the enhancement of their invasion ability. It may ultimately promote the establishment of a metastatic lesion.

Extracellular carbohydrate-signal triggering camp-dependent protein kinase-dependent neuronal actin-reorganization

Cell surface glycoconjugates are thought to mediate cell-cell recognition and to play roles in neuronal development and functions. We demonstrated here that exposure of neuronal cells to nanomolar levels of glyco-chains with an N-acetylgalactosamine (GalNAc) residue at the non-reducing termini (GalNAc-S) such as GalNAcbeta4(Neu5Acalpha3)Galbeta4GlcCer (GM2) ganglioside, its oligosaccharide portion, GalNAcbeta4Galbeta4GlcCer (Gg(3)) Cer, GalNAcalpha3GalNAcbeta3Galalpha4Galbeta4GlcCer (Gb(5)) Cer (Forssman hapten) and alpha1-4 linked oligomers of GalNAc, induced a rapid and transient activation of cAMP-dependent protein kinase (PKA) in subplasmalemma. The treatment was accompanied by peripheral actin polymerization and filopodia formation in NG108-15 cells and primary cultured hippocampal neurons, but not in glial cells. A cAMP-dependent protein kinase (PKA) selective inhibitor and an adenylate cyclase inhibitor blocked both PKA activation and the subsequent filopodia formation. A small GTPase cdc42 was a potential downstream target of GalNAc-S-activated PKA. These results suggest that extracellular GalNAc-S serve as potential regulators of the filopodia formation in neuronal cells by triggering the activation of PKA followed by cdc42 up-regulation via a cell surface receptor-like component. Filopodia formation induced by GalNAc-S may have a physiological relevance because long-term exposure to GalNAc-S enhanced F-actin-rich dendrite generation of primary cultured hippocampal neurons, and PKA-dependent dendritic outgrowth and branch formation of primary cultured cerebellar Purkinje neurons, in which actin isoforms were localized to motile structures in dendrites. These findings provide evidence for a novel GalNAc/PKA-signaling cascade in regulating some neuronal maturation.

Optical monitoring of synaptic summation along the dendrites of CA1 pyramidal neurons

The primary function of neurons is to integrate synaptic inputs and to transmit the results to other cells. Recent studies with somatic whole-cell recordings have shown that separate excitatory inputs to hippocampal or cortical pyramidal neurons are summated non-linearly. In the present study, we examined how postsynaptic potentials (PSPs) are summated along the dendrites employing fast optical voltage imaging techniques. Rat hippocampal slices were stained with a fluorescent voltage-sensitive dye (JPW1114) and optical signals were monitored with a 16 x 16 photodiode array system. Two independent input pathways were stimulated individually or in pairs through glass electrodes such that different locations of the dendrites received separate synaptic inputs. We found that (1) the summation of PSPs was sub-linear along the entirety of dendrites, (2) the blockade of GABA(A) receptors suppressed sub-linearity and (3) further blockade of GABA(B) receptors suppressed sub-linearity of the summation of separate inputs on apical dendrites. Our study demonstrates that pyramidal neurons integrate PSPs linearly along the entirety of dendrites; moreover, GABAergic inputs are responsible for maintaining sub-linear summation in CA1 pyramidal neurons.

A study of L-leucine, L-phenylalanine and L-alanine transport in the perfused rat mammary gland: possible involvement of LAT1 and LAT2

The transport of L-leucine, L-phenylalanine and L-alanine by the perfused lactating rat mammary gland has been examined using a rapid, paired-tracer dilution technique. The clearances of all three amino acids by the mammary gland consisted of a rising phase followed by a rapid fall-off, respectively, reflecting influx and efflux of the radiotracers. The peak clearance of L-leucine was inhibited by BCH (65%) and D-leucine (58%) but not by L-proline. The inhibition of L-leucine clearance by BCH and D-leucine was not additive. L-leucine inhibited the peak clearance of radiolabelled L-leucine by 78%. BCH also inhibited the peak clearance of L-phenylalanine (66%) and L-alanine (33%) by the perfused mammary gland. Lactating rat mammary tissue was found to express both LAT1 and LAT2 mRNA. The results suggest that system L is situated in the basolateral aspect of the lactating rat mammary epithelium and thus probably plays a central role in neutral amino acid uptake from blood. The finding that L-alanine uptake by the gland was inhibited by BCH suggests that LAT2 may make a significant contribution to neutral amino acid uptake by the mammary epithelium.

Changes in expression and function of syncytin and its receptor, amino acid transport system B(0) (ASCT2), in human placental choriocarcinoma BeWo cells during syncytialization

Relative abundance of mRNAs encoding syncytin and its receptor, amino acid transport system B(0), and activity of amino acid transport thought to be through this system have been studied in parallel in a cell model of syncytialization (BeWo cell following forskolin treatment). Relative mRNA abundance (determined by reverse transcription-polymerase chain reaction) for syncytin showed stimulation by forskolin. In contrast, the level of amino acid transporter B(0) mRNA expression was lower in forskolin treated cells. Na(+)-dependent alpha-(methylamino)isobutyric acid insensitive L -alanine transport was similarly decreased significantly in cells treated with forskolin suggesting that there is modulation of cell surface expression of the syncytin receptor associated with syncytialization.

GABAergic control of synaptic summation in hippocampal CA1 pyramidal neurons

The primary function of neurons is to integrate synaptic inputs and to transmit the results to other cells. It was shown previously that separate excitatory inputs to hippocampal pyramidal neurons are summated nonlinearly. In the hippocampus, responses of pyramidal neurons are influenced by GABAergic inputs in feed-forward or feedback manner, and also by oscillatory network activities. It is likely that these GABAergic inputs regulate the way synaptic inputs are summated. To examine the roles of GABAergic inputs on synaptic summation, we made whole-cell recordings from the cell bodies of CA1 pyramidal neurons in rat hippocampal slices while stimulating two independent input pathways with short interstimulus intervals, and examined the manner by which postsynaptic potentials were summated. We found that: 1) the summation of the perforant pathway and the Schaffer collateral pathway inputs was sublinear when the interval between two inputs was shorter than 30 ms, 2) the blockade of GABA(A) receptors partially suppressed the sublinearity, and 3) further blockade of GABA(B) receptors removed the sublinearity totally. We also found that 4) the summation was superlinear under the concomitant blockade of GABA(A) and GABA(B) receptors when the two inputs arrived with no delay. Thus our study demonstrates that GABAergic inputs are responsible for keeping the summation of two separate inputs on CA1 pyramidal neurons sublinear.

Establishment of human cementifying fibroma cell lines by transfection with temperature-sensitive simian virus-40 T-antigen gene and hTERT gene

Human cementifying fibroma (HCF) is a benign fibro-osseous neoplasm of periodontal ligament (PDL) origin containing varying amounts of mineralized material resembling cementum. In the present study, we established cell lines from HCF, which were detected in the mandible of a 54-year-old Japanese man. To obtain immortalized cell clones, we undertook transfection with temperature-sensitive simian virus-40 (SV40) T-antigen and hTERT into HCF cells. Cells transfected with SV40 T-antigen entered "crisis" state between passages 22 and 35, but activation of telomerase by transfection with hTERT in the SV40-transformed HCF cells resulted in bypass of the crisis and maintenance over passage 200. HCF cell lines decreased the expression of SV40 T-antigen and the activity of cell proliferation at a nonpermissive temperature (39 degrees C) in comparison with that at a permissive temperature (33 degrees C). High activities of alkaline phosphatase and mineralization and the expression of type I collagen, osteocalcin, osteopontin, and bone sialoprotein by reverse transcription-polymerase chain reaction (RT-PCR) were observed in HCF cells at 39 degrees C. Overall, these findings suggest that: (i) HCF cell lines may represent a novel in vitro human cell model for the study of the regulatory mechanism of differentiation and proliferation of the human PDL; and (ii) transfection of plasmids encoding the temperature-sensitive SV40 T-antigen gene and hTERT gene may be useful for obtaining immortalized cell lines from benign human tumor and, probably, nonneoplastic human tissues.

Oxidized low-density lipoprotein-binding specificity of Asp-hemolysin from Aspergillus fumigatus

Oxidized low-density lipoprotein (Ox-LDL) is known to be involved in the generation and progression of atherosclerosis. Ox-LDL has a number of potentially atherogenic effects on vascular cells, including the uncontrolled uptake by scavenger receptors. We have previously shown that Asp-hemolysin binds to Ox-LDL in a concentration-dependent manner. The present study was undertaken to clarify the binding specificity of Asp-hemolysin to Ox-LDL. We examined the binding specificity of Asp-hemolysin to Ox-LDL using several modified lipoproteins and scavenger receptor ligands. Asp-hemolysin bound to Ox-LDL with shorter LDL oxidation times. However, Asp-hemolysin did not bind to the acetylated LDL. The native high-density lipoprotein (n-HDL) and modified HDL (e.g., acetylated HDL, oxidized HDL) also had no Asp-hemolysin binding. Furthermore, inhibitors of the scavenger receptor binding, including maleylated BSA, polyinosinic acid, dextran sulfate and fucoidin, had no effect on the binding of Ox-LDL to Asp-hemolysin. Surface plasmon resonance studies revealed that Ox-LDL binds with high affinity (K(D)=0.63 microg/ml) to Asp-hemolysin. We concluded that Asp-hemolysin is a specific binding protein with a high affinity for Ox-LDL, and its binding specificity is distinct from any receptor for Ox-LDL. The present studies suggest that Asp-hemolysin may bind to Ox-LDL using a mechanism different from the scavenger receptors.

Transient occurrence of 27 kDa heat-shock protein in the terminal tubule cells during postnatal development of the rat submandibular gland

It has been suggested that the 27 kDa heat-shock protein (Hsp27) plays a role at crucial cellular checkpoints for proliferation, apoptosis, and differentiation. We examined the immunolocalization of Hsp27 in the rat submandibular gland during postnatal development, wherein acinar cells proliferate and differentiate at earlier postnatal periods. At 2 weeks of age, weak Hsp27 immunoreactivity was distributed diffusely over all gland components. At 3 weeks, Hsp27 immunoreactivity disappeared in most parts of the acini and ducts, but was intensely accumulated in a small cell population located in the acinar center. This population was composed mostly of terminal tubule (TT) type I cells. At 4 weeks, the Hsp27-immunopositive cell population in the acinar center was composed primarily of immature (type II) acinar cells, partly of immature (granulated) intercalated duct (ID) cells, and occasionally of apoptotic cells. After 5 weeks, all acinar components became mature and were no longer immunoreactive for Hsp27. When acinar cell differentiation was accelerated by administration of isoproterenol to 3-week-old rats for 7 days, the number of Hsp27-positive cells was significantly lower than in the control gland at 4 weeks, confirming that Hsp27 expression is downregulated in mature acinar cells. These results suggest that at around 3-4 weeks in postnatal development, the centroacinar TT cells stop proliferating and begin to differentiate into acinar and ID cells, and occasionally undergo apoptosis. Hsp27 is transiently expressed in the centroacinar TT cells during this critical period, and thus may play a role in their differentiation into the immediate descendants.

Functional and molecular characterization of a peptide transporter in the rat PC12 neuroendocrine cell line

We have studied functional properties of peptide transport in the pheochromocytoma neuroendocrine cell line from rat. The neutral peptide D-Phe-L-Ala (resistant to hydrolysis) is a good substrate for uptake into these cells. Transport is substantially inhibited by diethylpyrocarbonate pretreatment and is stimulated by external acidification. It is sodium-independent and, unexpectedly, insensitive to membrane potential. Peptide uptake is inhibited by a wide variety of other di- and tripeptides but not by amino acids. The neuropeptide kyotorphin (opioid dipeptide (L-Tyr-L-Arg)) inhibits uptake of labelled peptide and trans-stimulates efflux showing that it is a transported substrate. These findings are discussed in relation to the molecular basis and physiological role of this transport system.

Establishment of CHO cell lines expressing four N-methyl-D-aspartate receptor subtypes and characterization of a novel antagonist PPDC

To develop an assay system that allows the N-methyl-D-aspartate (NMDA) receptor subtype-selective antagonistic potency of drugs, we have established Chinese hamster ovary cell lines expressing the four NMDA receptor subtypes (GluRepsilon1/zeta1-GluRepsilon4/zeta1) heat-indelibly. Using these clonal cells, we found that a novel antagonist, (1S,2R)-1-phenyl-2[(S)-1-aminopropyl]-N,N-diethylcyclopropanecarboxamide, was less selective for the GluRepsilon1/zeta1: the IC(50) values for the GluRepsilon1/zeta1-GluRepsilon4/zeta1 were 41.7, 13.3, 12.6 and 11.5 microM, respectively, while two well-known antagonists, DL-2-amino-5-phosphonovaleric acid and ifenprodil, showed the known potency and selectivity for each subtype. Thus, the established clonal cells are of use in characterizing the pharmacological properties of drugs that act on NMDA receptors.

Analysis of codon usage diversity of bacterial genes with a self-organizing map (SOM): characterization of horizontally transferred genes with emphasis on the E. coli O157 genome

With increases in the amounts of available DNA sequence data, it has become increasingly important to develop tools for comprehensive systematic analysis and comparison of species-specific characteristics of protein-coding sequences for a wide variety of genomes. In the present study, we used a novel neural-network algorithm, a self-organizing map (SOM), to efficiently and comprehensively analyze codon usage in approximately 60,000 genes from 29 bacterial species simultaneously. This SOM makes it possible to cluster and visualize genes of individual species separately at a much higher resolution than can be obtained with principal component analysis. The organization of the SOM can be explained by the genome G+C% and tRNA compositions of the individual species. We used SOM to examine codon usage heterogeneity in the E. coli O157 genome, which contains 'O157-unique segments' (O-islands), and showed that SOM is a powerful tool for characterization of horizontally transferred genes.

Codon usage and tRNA genes in eukaryotes: correlation of codon usage diversity with translation efficiency and with CG-dinucleotide usage as assessed by multivariate analysis

The species-specific diversity of codon usage in five eukaryotes (Schizosaccharomyces pombe, Caenorhabditis elegans, Drosophila melanogaster, Xenopus laevis, and Homo sapiens) was investigated with principal component analysis. Optimal codons for translation were predicted on the basis of tRNA-gene copy numbers. Highly expressed genes, such as those encoding ribosomal proteins and histones in S. pombe, C. elegans, and D. melanogaster, have biased patterns of codon usage which have been observed in a wide range of unicellular organisms. In S. pombe and C. elegans, codons contributing positively to the principal component with the largest variance (Z1-parameter) corresponded to the optimal codons which were predicted on the basis of tRNA gene numbers. In D. melanogaster, this correlation was less evident, and the codons contributing positively to the Z1-parameter corresponded primarily to codons with a C or G in the codon third position. In X. laevis and H. sapiens, codon usage in the genes encoding ribosomal proteins and histones was not significantly biased, suggesting that the primary factor influencing codon-usage diversity in these species is not translation efficiency. Codon-usage diversity in these species is known to reflect primarily isochore structures. In the present study, the second additional factor was explained by the level of use of codons containing CG-dinucleotides, and this is discussed with respect to transcription regulation via methylation of CG-dinucleotides, which is observed in mammalian genomes.

High expression of S-phase kinase-interacting protein 2, human F-box protein, correlates with poor prognosis in oral squamous cell carcinomas

Reduced expression of p27(Kip1), a cyclin-dependent kinase (Cdk) inhibitor, is frequently found in various cancers, including oral squamous cell carcinoma (OSCC), and is attributable to an enhancement of its degradation. Skp2, an F-box protein necessary for DNA replication, is required for the ubiquitinylation and subsequent degradation of p27(Kip1). In the present study, we examined the expression of Skp2 and its correlation with the expression of p27(Kip1) protein or p27(Kip1) degradation in OSCC. Using immunohistochemistry, we found that high expression of Skp2 was present in 49% of OSCCs and only 20% of epithelial dysplasias. Significantly, high expression of Skp2 was correlated with poor prognosis of OSCC patients. We also found an inverse correlation between the expression of Skp2 and p27 by immunohistochemical analysis. A similar correlation was observed in OSCC cell lines and OSCC tissues by Western blot analysis. Interestingly, OSCC tissues with Skp2 expression had high p27(Kip1) degradation activity. These findings indicate that (a) Skp2 may play an important role for the development of OSCC, (b) Skp2 can be a novel target for OSCC treatment as well as a strong prognostic marker, and (c) the reduction in p27(Kip1) protein may be brought about by enhancement of its degradation mediated by increased levels of Skp2 protein.

Functional expression of alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptors precedes the development of cholinergic phenotype in embryonic rat septal cells in culture

We examined the development of cholinergic neuronal functions and alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) responses in cultured embryonic rat septal cells. Choline acetyltransferase activity was increased from 4 to 6 days in culture and reached a plateau at day 8. Acetylcholine release was increased from 6 to 8 days in culture. AMPA-induced increase in intracellular Ca(2+) level was observed at 3 days in culture and most of the AMPA-responsive cells coincided with high-K(+) responsive cells. These results suggest that cholinergic neurons develop their neuronal functions about 8 days under cultured conditions, and functional expression of AMPA receptors precedes the cholinergic functional development.

Tryptophan degradation by human placental indoleamine 2,3-dioxygenase regulates lymphocyte proliferation

1. The physiological importance of human placental indoleamine 2,3-dioxygenase (EC 1.13.11.42), the first and rate-limiting enzyme in tryptophan metabolism, in regulating feto-maternal immunology has been studied. 2. Concentrations were measured in placental villous explant conditioned media of 14 amino acids that are known to be required for lymphocyte proliferation. In the absence of interferon-gamma only tryptophan and threonine were significantly lowered; in the presence of interferon-gamma (known to stimulate indoleamine 2,3-dioxygenase) tryptophan but not threonine depletion was much greater. 3. Peripheral blood mononuclear cell proliferation determined by measuring thymidine incorporation into DNA following culture in the medium previously conditioned by culture of villous explants was markedly reduced when placental indoleamine 2,3-dioxygenase was stimulated with interferon-gamma. Inhibition of placental indoleamine 2,3-dioxygenase by 1-methyl-tryptophan prevented inhibition of thymidine incorporation. Supplementation of the conditioned medium with tryptophan but no other amino acid completely reversed the inhibition of thymidine incorporation. 4. Flow cytometric analysis showed that CD4-positive T lymphocyte division was specifically suppressed by indoleamine 2,3-dioxygenase-mediated tryptophan depletion. This inhibition of T cell proliferation was due to arrest of cell cycle progression. 5. To study the mechanism of tryptophan sensing we examined the ability of 11 L-tryptophan analogues to support lymphocyte proliferation. Only L-tryptophan methyl and ethyl esters were able to stimulate proliferation in tryptophan-free media. Since both of these molecules are readily degraded to tryptophan by intracellular esterases this suggests that the tryptophan sensor is intracellular. 6. Our results show that mechanisms are present in the human placenta which are able to regulate cellular proliferation of the maternal immune system. This mechanism is dependent both on placental indoleamine 2,3-dioxygenase-mediated tryptophan degradation and on tryptophan sensing systems within lymphocytes.

Dendritic attenuation of synaptic potentials in the CA1 region of rat hippocampal slices detected with an optical method

We directly measured fast excitatory postsynaptic potentials (EPSPs) along the dendrites of hippocampal CA1 pyramidal neurons by employing an optical method to study how synaptic potentials spread along the dendrites. Rat hippocampal slices were stained with a fluorescent voltage-sensitive dye JPW1114 and optical signals were monitored with a 16 x 16 photodiode array system. A stimulating electrode was placed either at stratum lacunosum moleculare to activate perforant fibers that make synaptic contacts to the distal apical dendrites or at stratum oriens to induce EPSPs at the basal dendrites of CA1 pyramidal cells. CNQX-sensitive components of the optical signals, which were assumed to be population EPSPs, were isolated. Propagation and attenuation of the CNQX components were successfully observed with the optical method. At the cell body layer, the peak of the CNQX-sensitive component was delayed by 17.08 +/- 1.64 ms from the input sites. Additionally we performed a simulation study to estimate the passive membrane parameters of the apical dendrites. Estimated apparent specific internal axial resistance (Ri) following stratum lacunosum moleculare stimulation was 76.0 +/- 4.2 Omega.cm and apparent specific membrane resistance (Rm) was 27.8 +/- 2.1 kOmega.cm2 (assuming the specific membrane capacitance of dendrites Cm = 1.6 microF/cm2). These values are comparable to those previously reported. When synaptic inputs were applied at stratum oriens, these apparent passive membrane parameters were different (high Ri and low Rm), suggesting that nonuniform dendritic membrane conductance or voltage-dependent conductances which are active near the resting potential may contribute to the measured passive membrane properties.

Cytokine expression in rat molar gingival periodontal tissues after topical application of lipopolysaccharide

It is well known that proinflammatory cytokines produced by host cells play an important role in periodontal tissue destruction. However, the localization of the cytokines in in vivo periodontal tissues during development of periodontal disease has not been determined. Immunohistochemical expression of proinflammatory cytokines including IL-1alpha, IL-1beta, and TNF-alpha was examined at 1 and 3 h, and 1, 2, 3, and 7 days after topical application of lipopolysaccharide (LPS; 5 mg/ml in physiological saline) from E. coli into the rat molar gingival sulcus. In the normal periodontal tissues, a small number of cytokine-positive epithelial cells were seen in the junctional epithelium (JE), oral sulcular and oral gingival epithelium, in addition to macrophages infiltrating in the subjunctional epithelial area and osteoblasts lining the alveolar bone surface. Epithelial remnants of Malassez existing throughout periodontal ligament were intensely positive for IL-1beta but negative for the other two cytokines. At 3 h after the LPS treatment, almost all cells in the JE were strongly positive for the cytokines examined. In addition, several cytokine-positive cells, including neutrophils, macrophages, and fibroblasts, were seen in the subjunctional epithelial connective tissue. At day 2, expression of the cytokines in the JE gradually decreased, while cytokine-positive cells in the connective tissue increased in number. Positive staining of the cytokines was seen in osteoclasts and preosteoclasts which appeared along the alveolar bone margin in this period. The number of cytokine-positive cells decreased by day 7. These findings indicate that, in addition to macrophages, neutrophils, and fibroblasts, the JE cells are a potent source of TNF-alpha, IL-1alpha, and IL-1beta reacting to LPS application, and suggest that JE cells may play an important role in the first line of defense against LPS challenge, and the proinflammatory cytokines transiently produced by various host cells may be involved in the initiation of inflammation and subsequent periodontal tissue destruction.

Erythrocyte creatine as a marker of excessive erythrocyte destruction due to hypersplenism in patients with liver cirrhosis

OBJECTIVE

Erythrocyte creatine is a sensitive marker of erythrocyte age, and can be used to detect slight and continuous hemolysis. Excessive blood cell destruction caused by increased spleen function is important evidence of hypersplenism. This study evaluates the usefulness of erythrocyte creatine as a sensitive marker of excessive erythrocyte destruction due to hypersplenism in patients with liver cirrhosis.

DESIGN AND METHOD

Erythrocyte creatine was determined by an enzymatic method in 50 patients with postnecrotic liver cirrhosis and 50 healthy controls. The spleen size was measured by ultrasonography and expressed as a spleen index.

RESULTS

The patients with splenomegaly showed significantly higher erythrocyte creatine than those without splenomegaly (p < 0.005) and healthy controls (p < 0.001), but there was no significant difference in erythrocyte creatine between healthy controls and those without splenomegaly. Fourteen (93%) of the 15 patients with abnormally high erythrocyte creatine (> 1.8 micromol/g hemoglobin) had splenomegaly. There were no significant differences in reticulocyte count between healthy controls and the patients with and without splenomegaly. Erythrocyte creatine showed good correlations with spleen index (r = 0.67; p < 0.001) and reticulocytes (r = 0.63; p < 0.001).

CONCLUSIONS

Erythrocyte creatine can be used for predicting erythropoietic status and estimating hypersplenism in patients with liver cirrhosis.

Successful hyperbaric oxygen treatment of life-threatening hemorrhagic cystitis after allogeneic bone marrow transplantation

Hemorrhagic cystitis (HC) is a major cause of morbidity after allogeneic bone marrow transplantation (BMT). Many therapies have been investigated to prevent or treat HC, but effective treatment for HC is still limited. While the efficacy of hyperbaric oxygen therapy has been established for HC due to chemotherapy and/or radiation therapy, its role in HC occurring after allogeneic BMT has yet to be defined. We report two cases of life-threatening late-onset HC after allogeneic BMT in children, which resolved after treatment with hyperbaric oxygen.

Association of structural polymorphisms in the human period3 gene with delayed sleep phase syndrome

Recent progress in biological clock research has facilitated genetic analysis of circadian rhythm sleep disorders, such as delayed sleep phase syndrome (DSPS) and non-24-h sleep-wake syndrome (N-24). We analyzed the human period3 (hPer3) gene, one of the human homologs of the Drosophila clock-gene period (Per), as a possible candidate for rhythm disorder susceptibility. All of the coding exons in the hPer3 gene were screened for polymorphisms by a PCR-based strategy using genomic DNA samples from sleep disorder patients and control subjects. We identified six sequence variations with amino acid changes, of which five were common and predicted four haplotypes of the hPer3 gene. One of the haplotypes was significantly associated with DSPS (Bonferroni's corrected P = 0.037; odds ratio = 7.79; 95% CI 1.59-38.3) in our study population. Our results suggest that structural polymorphisms in the hPer3 gene may be implicated in the pathogenesis of DSPS.

[Cytotoxic activity and cytokine gene induction of Asp-hemolysin to vascular endothelial cells]

We examined the effects of Asp-hemolysin from Aspergillus fumigatus Fresenius-Muramatsu strain on the viability and cytokine gene expression of human umbilical vein endothelial cells (HUVEC). The cell viability of HUVEC was reduced to 50% by 100 micrograms/ml of Asp-hemolysin. However, lower concentration of Asp-hemolysin (< 30 micrograms/ml) had no effect on the cell viability. The mRNA expression of such cytokines as tumor necrosis factor-alpha (TNF-alpha), interleukin (IL)-1 beta, IL-6, IL-8 and granulocyte-macrophage colony stimulating factor (GM-CSF) were also observed in HUVEC cultured with 30 micrograms/ml of Asp-hemolysin.

[Effects of low density lipoprotein and oxidized low density lipoprotein on the cytotoxic activity of Asp-hemolysin to murine macrophages]

We examined the effects of human low density lipoprotein (LDL) and oxidized LDL (Ox-LDL) on the cytotoxic activity of Asp-hemolysin from Aspergillus fumigatus Fresenius-Muramatsu strain to mouse peritoneal macrophages (M phi). The inhibitory effects of LDL and Ox-LDL on the cytotoxic activity of Asp-hemolysin to M phi increased in a dose-dependent manner, and the effect of Ox-LDL was greater than the inhibitory effect of LDL. Furthermore, the binding of Asp-hemolysin to LDL or Ox-LDL was observed by western blot analysis of the culture medium. These results suggest that the inhibition by LDL or Ox-LDL on the cytotoxic activity of Asp-hemolysin to M phi was due to the binding of LDL or Ox-LDL to Asp-hemolysin in the culture medium.

Visualization of oxygen-concentration-dependent production of nitric oxide in rat hippocampal slices during aglycemia

Our novel fluorescent indicator, DAF-FM, permits the bioimaging of nitric oxide (NO) in living cells with high resolution in space and time, with stable intensity above pH 5.8. A membrane-permeable derivative, DAF-FM DA, was applied to imaging of NO generated in rat hippocampal slices by exposure to an aglycemic medium. NO production was observed mainly in the CA1 area, and was dependent on the concentration of O(2). During exposure to an anoxic-aglycemic medium, NO was hardly produced, while marked elevation of intracellular Ca(2+) was observed. Production of NO increased sharply as soon as the perfusate was changed to the normal medium. These results suggest that NO synthase is activated after reperfusion rather than during ischemia.

Characterisation of L-tryptophan transporters in human placenta: a comparison of brush border and basal membrane vesicles

The mechanisms responsible for L-tryptophan transport at both the maternal- and fetal-facing surfaces of the term placenta have been determined in isolated membrane vesicles as part of a study on placental indoleamine 2,3-dioxygenase, the L-tryptophan-catabolising enzyme recently shown to regulate feto-maternal immunology. Brush border vesicle uptake of L-tryptophan is substantially into an osmotically active space. It is sodium independent and N-ethylmaleimide sensitive. Uptake of L-tryptophan, which is markedly stereospecific, has a Km of 26.3 microM and Vmax of 1.72 pmol (mg protein)(-1) s(-1) and is completely abolished by the L-system-specific substrate 2-aminobicyclo-(2,2,1)-heptane-2-carboxylic acid (BCH). These findings are in keeping with L-tryptophan transport being exclusively via system L (induced by the heterodimeric heavy chain of CD98 and system L-amino acid transporter-1 (LAT-1)). 1-Methyl-tryptophan (which is a known competitive inhibitor of indoleamine 2,3-dioxygenase) is a competitive inhibitor of L-tryptophan flux through this transport system (Ki = 113 microM). Basal membrane transport of L-tryptophan is more complex. Uptake is slower than at the brush border and although, as in the brush border, uptake is sodium independent, it is less sensitive to N-ethylmaleimide. There is clear evidence that two systems contribute to basal membrane transport since BCH is (in sodium-free media) only a partial inhibitor whereas L-histidine and L-cysteine are fully effective. The simplest explanation of these and other findings is that the basal membrane possesses two systems, one of which is similar to that induced by the heavy chain of CD98 and system L-amino acid transporter-2 (LAT-2). The other appears to be system y+L since in the presence of BCH inhibition by L-leucine but not by L-lysine is sodium dependent. These findings suggest the existence of non-identical carrier-mediated transport systems for L-tryptophan in brush border and basal membranes. This asymmetry may explain net transplacental transfer of this amino acid.

The role of L-tryptophan transport in L-tryptophan degradation by indoleamine 2,3-dioxygenase in human placental explants

The physiological importance of L-tryptophan transport for placental indoleamine 2,3-dioxygenase-mediated degradation of L-tryptophan has been studied using human placental chorionic villous explants. L-Tryptophan influx into villous explants is supported exclusively by transport system L and is substantially inhibited by the L-system-specific substrate 2-aminobicyclo-(2,2,1)-heptane-2-carboxylic acid (BCH) and also by 1-methyl-tryptophan which is also an inhibitor of indoleamine 2,3-dioxygenase. L-Tryptophan influx is enhanced 2.3-fold following in vitro culture of the villous explant. Interferon-gamma, which increases villous explant indoleamine 2,3-dioxygenase expression, has no effect on L-tryptophan influx. In explants both BCH and 1-methyl-tryptophan inhibit indoleamine 2,3-dioxygenase-mediated L-tryptophan degradation. This also applies when L-tryptophan degradation has been stimulated by interferon-gamma. These findings show transport of L-tryptophan into the trophoblast to be a rate-limiting step for indoleamine 2,3-dioxygenase-mediated L-tryptophan degradation and therefore for the normal physiology of mammalian pregnancy.

Low-threshold potassium channels and a low-threshold calcium channel regulate Ca2+ spike firing in the dendrites of cerebellar Purkinje neurons: a modeling study

Various types of voltage-gated ion channels are distributed along the dendrites of neurons in the central nervous system. We have recently shown experimentally that the dendrites of cerebellar Purkinje neurons contain low-threshold voltage-gated Ca(2+) channels and low-threshold voltage-gated K+ channels. Although we found that these channels are involved in regulating the onset of Ca(2+)-dependent action potentials in the dendrites, we were unable to identify which of the known types of low-threshold Ca2+ channels and K+ channels were responsible, since there was no reliable method of discriminating between them. Here, we have built a detailed compartmental model of a Purkinje neuron by incorporating two types of low-threshold Ca2+ channel (T-type and class-E, or R-type) and two types of low-threshold K+ channel (A-type and D-type), in addition to another eight voltage-gated channel types, using a compartmental model neuron simulator. The model reproduces the basic features of the depolarization-induced responses of Purkinje neurons, such as fast Na+ spikes in the soma, Ca2+ spikes in the dendrites, the slow onset of Ca2+ spikes, repetitive Ca2+ spikes in the presence of TTX, the marked shortening of Ca2+ spike onset in the presence of 4-aminopydridine, and the longer Ca2+ spike onset in the presence of Ni2+. Our model shows that the D-type K+ channel and the class-E Ca2+ channel regulate the onset of depolarization-induced Ca2+ spikes in Purkinje neurons. These channels might be involved in integrating synaptic inputs in Purkinje neurons.

Real-time, two-dimensional visualization of ischaemia-induced glutamate release from hippocampal slices

The involvement of excitatory amino acid (EAA) toxicity in ischaemia-induced neuronal cell death has long been suggested. However, in the hippocampus, the brain site most vulnerable to ischaemia, the detailed spatial and temporal patterns of EAA release are not yet known. To address this issue, we have developed a novel strategy for the continuous, real-time, two-dimensional monitoring of EAA release from brain slices. As EAA detector, we used a cell line transformed with the N-methyl-D-aspartate (NMDA) receptor, which is exclusively activated by EAAs, leading to an increase in the intracellular Ca(2+) level. Combined with a calcium imaging technique, the use of this cell line allowed the temporal and regional analysis of EAA release from a brain slice placed directly on top of the clonal cells in a culture dish. Using this strategy, we demonstrated ischaemia-induced EAA release in rat hippocampal slices. Increased EAA release was seen initially in the CA1 region, about 3 min after the beginning of ischaemia, then in the CA3 region and dentate gyrus, and, finally, throughout the hippocampal slice. Regional differences in extracellular EAA levels were also seen, with more EAA being released from the CA1 region than from the middle dentate gyrus. The present results are especially interesting as neurons in the CA1 region are more vulnerable to ischaemia than those in the CA3 region and dentate gyrus.

Flow cytometric analysis of hemetopoietic progenitor cells in peripheral blood stem cell harvest from patients with CD34 positive acute leukemia

We analyzed CD34 positive cells in peripheral blood stem cell harvest (PBSCH) using flow cytometry. PBSCH from CD34 positive acute myelogeous leukemia (AML-M2) patient contained 1.87% CD34 positive cells, of which 1.21% was represented by MRD.PBSCH from CD34 positive acute lymphoblast leukemia (ALL) patient contained 3.14% CD34 positive cells, of which 0.11% was accounted for by minimal residual disease (MRD). If PBSCH from CD34 positive acute leukemia patient is analyzed for CD34 monoclonal antibody alone, the presence of CD34 positive MRD may escape attention so that CD34 positive hematopoietic progenitor cells may be overestimated. To avoid this risk, it is necessary to analyze PBSCH using both CD34 monoclonal antibody and characteristic markers of leukemia cells that were found pre-treatment.

Peripheral ameloblastoma: biological profile based on 160 cases from the literature

The present profile of the peripheral ameloblastoma (PA) is based on a literature survey of 160 published tumour cases. The PA is an exophytic growth localized to the soft tissues overlying the tooth-bearing areas of the jaws, the initial diagnosis often being fibrous epulis. In most cases there is no radiological evidence of bone involvement, but a superficial bone erosion--known as cupping or saucerization--may be detected at operation. The PA accounts for 2-10% of all ameloblastomas. The overall average age is 52.1 years, slightly higher for males (52.9 years) than for females (50.6 years). Thus, the PA occurs at a significantly higher age than the intraosseous ameloblastoma (IA; 37.4 years). The male/female ratio amounts to 1.9:1, as opposed to 1.2:1 for the IA. The male/female ratio for the Japanese cases included in this survey is 2.5:1 as opposed to that of non-Japanese cases 1.4:1. As to the location of PA, the maxilla/mandible ratio is 1:2.6. The mandibular premolar region accounts for 32.6% of all sites. Five extra-gingival lesions have been reported under the term PA. As these cases most likely represent salivary gland tumours, they are not accepted under the diagnosis of PA. The odontogenic gingival epithelial hamartoma shows clinical, histological and behavioural features almost identical to the PA, and it is discussed whether this lesion and the PA should be considered one and the same entity. Pathogenetically, two major sources are discussed: remnants of the dental lamina and the oral surface epithelium. Histologically, the PA consists of proliferating odontogenic epithelium exhibiting the same histomorphological cell types and patterns as seen in the IA. The stroma is that of a mature, fibrous connective tissue. The indolent biological behaviour dictates a conservative therapeutical approach. It is discussed whether PA is a true neoplastic counterpart of the IA or rather an odontogenic hamartomatous lesion. Six cases of malignant PA have been reported.

Diurnal fluctuation of sleep propensity and hormonal secretion across the menstrual cycle

BACKGROUND

The fact that most women experience sleep changes across the menstrual cycle is thought to be associated with changes in circadian rhythms; however, few studies have investigated this relationship.

METHODS

We applied an ultrashort sleep-wake schedule to eight healthy women and studied diurnal fluctuations in sleep propensity, sleepiness, rectal temperature, and serum concentrations of melatonin, thyroid-stimulating hormone, and cortisol in the follicular and luteal phases.

RESULTS

In the luteal phase, amplitude of core body temperature, total melatonin secretions, and amplitudes of TSH and cortisol rhythms were significantly decreased, whereas sleepiness and occurrence of slow-wave sleep during the daytime were significantly increased. Differences in the amount of daytime slow-wave sleep across the menstrual cycle were positively correlated with differences in the daily mean rectal temperature.

CONCLUSIONS

The findings suggest that the amplitude of circadian oscillation may be dampened in the luteal phase. Increased daytime sleepiness in the luteal phase may be associated with increased daytime slow-wave sleep, due possibly to changes in thermoregulation in the luteal phase.

Altered phase relation between sleep timing and core body temperature rhythm in delayed sleep phase syndrome and non-24-hour sleep-wake syndrome in humans

Changes in the phase relation between sleep timing and the circadian pacemaker are suspected to have an etiological significance in circadian rhythm sleep disorders. Simultaneous recordings of rest-activity and rectal temperature in seven sighted delayed sleep phase syndrome (DSPS) patients, seven sighted non-24-h sleep-wake syndrome (non-24) patients, and 14 healthy controls were made for 10-14 days continuously in the subjects' homes. We found that sleep length and the interval from the body temperature (BT) trough to sleep offset were significantly longer in both non-24 and DSPS patients than in the controls, and that the interval between sleep onset and the BT trough was significantly less in the non-24 patients than in the DSPS patients and the controls. We postulate these alterations in phase relation to be associated with phase changes of the circadian pacemaker via different illumination timings.

Reduced expression of CD44 variant 9 is related to lymph node metastasis and poor survival in squamous cell carcinoma of tongue

Expression of CD44v9 was immunohistochemically studied in 120 biopsy specimens from primary squamous cell carcinoma (SCC) of the tongue and correlated with clinicopathological findings of the SCCs. The tumors were classified into three groups according to immunostaining pattern of CD44v9; 53 cases with distinct positivity in all cancer cells except for those in the central part of nests (Group 1, non-reduced group), 42 cases with reduced expression in peripheral cells of nests (Group 2, reduced group), and 25 cases with complete disappearance of the expression in one or more nests (Group 3, negative group). Nineteen of 25 (76%) tumors in Group 3 and 14 of 42 (33%) in Group 2 exhibited lymph node metastasis, compared with only 8 of 53 (15%) in Group 1. The average survival time in Groups 1, 2 and 3 was 4496+/-204, 3866+/-379 and 2719+/-359 days, respectively and became shorter with the reduction of CD44v9 expression. These results suggest that the down-regulation of CD44v9 in SCC of the tongue may relate to the detachment of tumor cells from primary lesions, establishment of lymph node metastasis and consequently the death of patients.

The design of cyclic AMP--recognizing oligopeptides and evaluation of its capability for cyclic AMP recognition using an electrochemical system

A novel 17-mer peptide ligand for cyclic AMP was designed using the amino acid sequences of essential subsites in various cyclic AMP-dependent protein kinase (protein kinase A) families. The Au disk electrode, which was modified with the designed 17-mer oligopeptide, responded to cyclic AMP but virtually did not respond to any other cyclic nucleotides using the ion channel sensor mechanism. On the other hand, a scrambled peptide, which had the same amino acid composition as and had an amino acid sequence different from the 17-mer oligopeptide, did not respond to any nucleotides. This indicates that the designed 17-mer peptide actually acted as a selective ligand for cyclic AMP. This ligand-designing strategy using peptide sequences in target-binding proteins may possibly be extended to the design of peptide ligands for other second messengers.

Two deletion mutations in the hydroxymethylbilane synthase gene in two unrelated Japanese patients with acute intermittent porphyria

Acute intermittent porphyria (AIP) is an autosomal dominant inherited disease caused by a decreased activity of hydroxymethylbilane synthase (HMBS). Regarding the abnormalities of the HMBS gene, many different mutations have been reported worldwide; however, few families from Japan have been studied. In this work, we investigated the presence of mutations in two unrelated Japanese patients with AIP. Mutational analysis was performed using the polymerase chain reaction-single strand conformation polymorphism (SSCP) method, followed by DNA sequencing. Reliable restriction enzyme cleavage assays were also established for the pedigree analyses. Unique SSCP patterns were noted in exons 12 and 15 of the HMBS gene. Sequencing revealed different mutations in each patient: a two-base deletion of CT at nucleotide 730-731 (730delCT), and also a two-base deletion of CA at position 982-983 (982delCA). Both of the deletion mutations lead to truncated proteins with an abnormal C-terminus, which would be expected to decrease the stability and/or activity of HMBS. Using the cleavage assays, we were able to definitively identify gene carriers in the family. This study adds a novel mutation to those that have been previously reported, and emphasizes that molecular analysis would be very useful not only for the identification of asymptomatic gene carriers in the family but also for the detection of ancestral founders in porphyria families.

Evolution of meal patterns and food choices of Japanese-American females born in the United States

OBJECTIVES

To examine trends in meal patterns and food choices across two generations of Japanese-American females born in the USA.

DESIGN

Cross-sectional cohort study.

SETTING

Gardena, a suburb of Los Angeles, California.

SUBJECTS

One-hundred and seventy-six Japanese-American females, participating in a morning exercise class from December 1998 to January 1999.

INTERVENTION

Eighty-eight Nisei (second generation) mothers and their Sansei (third generation) daughters completed a food frequency questionnaire, answering questions regarding meal patterns and consumption frequency of 51 food items.

RESULTS

The Sansei ate fewer meals per day compared with the Nisei. Mean frequencies of takeout foods and eating out were higher in the Sansei vs the Nisei. Mean intake of meats and eggs were similar between the two groups. However, mean consumption of traditional Japanese complement foods including fish, vegetables and legumes was lower in the Sansei vs the Nisei. Intake of more 'Westernized' accessory foods, including salty snacks, regular soft drinks and alcoholic beverages, was higher in the Sansei vs the Nisei.

CONCLUSION

Findings from this study indicate that meal patterns and food choices have changed in succeeding generations of Japanese-American females from traditional fare to a diet containing many complement and accessory foods that are higher in fat, sugar, sodium and calories. Health professionals should be advised to consider the whole diet in making nutrition recommendations to this population as well as providing information to this group on the nutritional benefits of many traditional foods. European Journal of Clinical Nutrition (2000) 54, 665-670.

T-477, a novel Ca(2+)- and Na(+) channel blocker, prevents veratridine-induced neuronal injury

To evaluate the effect of (R)-(+)-2-(4-chlorophenyl)-2, 3-dihydro-4-diethyl aminoacetyl-4H-1,4-benzothiazine hydrochloride (T-477), a novel Na(+)- and Ca(2+) channel blocker, on neuronal injury in vitro, we studied veratridine-induced injury in cultured rat hippocampal neurons. Neurons swelled extensively 10 min after the addition of veratridine, and returned to their initial size within 2 h. Intracellular Na(+) and Ca(2+) concentrations and amino acid release from the cells, in particular, that of glutamate, increased after the treatment with veratridine. Approximately 70% of neurons died within 24 h. T-477 inhibited both veratridine-induced swelling and death in a concentration-dependent manner. Moreover, T-477 concentration dependently reduced the increases in Na(+) and Ca(2+) influx and amino acid release. These results suggest that T-477 prevented the veratridine-induced influx of Na(+) and, thereby, reduced neuronal swelling. This, combined with the effects of T-477 on the inhibition of Ca(2+) influx and glutamate release, possibly by the blockade of Na(+) channels, may be the mechanism by which T-477 protects neurons from death induced by veratridine.

Effects of small dose of brotizolam on P300

Nine healthy men (mean age, 22.2 years) participated in two experimental sessions cross-overed randomly in a double blind manner; one with a placebo and the other with 0.125 mg of brotizolam (BTZ) administered in the morning. Resting electroencephalogram and event-related potential under oddball paradigm was recorded before and 1, 2, 4, 6 and 8 h after the administration. Mean 30-msec bin amplitude from 240 msec to 450 msec after the stimulus was compared between placebo and drug sessions in order to observe P300. Brotizolam reduced the amplitude of P300 at 6 h after administration. It was noted that the effects of BTZ were most marked at Fz.

Melatonin treatment for circadian rhythm sleep disorders

This study investigated the effects of melatonin administration on circadian rhythm sleep disorders, and aimed to clarify clinical characteristics of melatonin responders. The subjects were 46 patients with circadian rhythm sleep disorders: 30 Delayed Sleep Phase Syndrome (DSPS) and 16 non-24 h sleep-wake syndrome (non-24). Patients took 0.3-1.0 mg of melatonin 5, 3 and 1 h before habitual bedtime. Seventeen patients responded to melatonin (12 DSPS, five non-24). Comparison of clinical background between responders and non-responders revealed that the responders were characterized by short total sleep time and later onset age of clinical symptoms.

Proteome analysis of Oncorhynchus species during embryogenesis

To understand the molecular mechanisms underlying normal and abnormal development of two salmonids, masu salmon (Oncorhynchus masou) and rainbow trout (O. mykiss), we used two-dimensional (2-D) electrophoresis to construct a series of 2-D maps during the embryonic period. We identified all visible protein spots on the 2-D map by assigning numbers for masu salmon and rainbow trout, and we determined N-terminal sequences of proteins for one hundred of the spots, that appear at very high concentrations in the whole embryos of masu salmon and rainbow trout. We also characterized embryonic stages according to the periods of appearance of spots. Most of the N-terminal sequences were identical or at least highly similar to partial sequences reported for vitellogenin (Vtg) of O. mykiss. A potential proteolytic processing of Vtg for rainbow trout is discussed in relation to the time of appearance and relative position of Vtg fragments within the complete protein sequence.

A newly designed underwater antenna and its application to underwater radio-telemetry for measuring electroencephalographic activity from the rainbow trout freely swimming in natural environments

A novel underwater antenna (which we named an 'aquaerial') for telemetering the biological signals from freely swimming fish in freshwater natural environments is presented. It is designed for receiving a 90-100 MHz carrier wave and consists of plural unit receiving antennas (UAs). The plural UAs are placed underwater to cover the area where the target fish carrying the transmitter is swimming. The UAs are equally spaced and have a directional coupling amplifier to supply the signals received to the coaxial cable. The optimal length of the UA was found to be 16.5 cm (a half wavelength in water) and optimal spacing was 2 m (one wavelength along coaxial cable) when 95 MHz was used as the carrier frequency. Using this 'aquaerial', long-term monitoring of EEG signals from the olfactory bulb of the rainbow trout (Oncorhynchus mykiss) swimming freely in natural environments was achieved.

Reduced expression of p27(Kip1) correlates with an early stage of cancer invasion in oral squamous cell carcinoma

Down-regulation of p27(Kip1) has been reported to correlate with poor survival of various carcinoma patients including oral squamous cell carcinomas (OSCCs). It is still unclear, however, at what stage of oral carcinogenesis the down-regulation of this protein occurs. In this study, therefore, we evaluated immunoexpression of p27(Kip1) protein in 17 cases of oral epithelial dysplasia and succeeding invasive OSCC in the same patient. We reported here that 88% cases showed high p27(Kip1) expression in dysplastic lesions, whereas 82% cases of succeeding invasive OSCC exhibited reduced expression. The reduction of p27(Kip1) expression was also observed in 16 of 19 (84%) early invasive lesions and well correlated with Ki-67 expression which is good indicator of cell proliferation. We also investigated immunoexpression of p53 protein of which abnormality has been known to occur during the early stage of OSCC development. Overexpression of p53 protein was demonstrated in 29% of dysplastic lesions, 42% of early invasive and 71% of invasive OSCCs. These findings suggest that abnormalities of both p53 and p27(Kip1) are involved in the carcinogenesis of OSCC, but they seem to play their role at different stages of oral cancer development, respectively. Reduced expression of p27(Kip1) may concern the cancer invasion directly or indirectly as well as abnormal proliferation.

Immunohistochemical demonstration of an enamel sheath protein, sheathlin, in odontogenic tumors

Enamel proteins can be useful markers for assessment of the functional differentiation of neoplastic epithelium and the nature of extracellular matrices in odontogenic tumors. In the present study, we examined immunohistochemical localization of sheathlin, a recently cloned enamel sheath protein, in various odontogenic tumors to evaluate functional differentiation of tumor cells and the nature of hyalinous or calcified matrices in odontogenic neoplasms. Distinct immunolocalization of sheathlin was observed in the immature enamel of the tooth germ at the late bell stage. Secretory ameloblasts facing the enamel matrix also showed positive staining in their cytoplasm. Definite localization of sheathlin was demonstrated in the enamel matrix in odontogenic tumors with inductive dental hard tissue formation such as ameloblastic fibroodontomas and odontomas. Immunoexpression of sheathlin was, furthermore, demonstrated in eosinophilic droplets in solid nests of adenomatoid odontogenic tumor (AOT) and ghost cells in the epithelial lining of calcifying odontogenic cyst (COC). In AOT, cells facing the eosinophilic droplets also expressed the protein in their cytoplasm. There was neither intracellular staining for sheathlin in the tumor cells nor extracellular staining in the matrix of ameloblastomas and calcifying epithelial odontogenic tumors. Dentin, dysplastic dentin-like hyaline material and cementum in the tumors examined were negative for sheathlin. These results show that immunodetection of sheathlin is a useful marker for functional differentiation of secretory ameloblasts and enamel matrix, which is often hard to differentiate from other hard tissues in odontogenic tumors. Our findings from the view point of sheathlin expression support that the tumor cells of ameloblastomas do not attain full differentiation into functional ameloblasts. It is very interesting that epithelial cells in odontogenic tumors can differentiate into functional ameloblasts without induction by odontogenic mesenchyme, as shown by immunoexpression of sheathlin in eosinophilic droplets within solid epithelial sheets in AOT and ghost cells in the epithelial lining of COC where inductive participation of mesenchymal cells was most unlikely.