Macrophage migration inhibitory factor and DJ-1 in gastric cancer: differences between high-incidence and low-incidence areas

BACKGROUND

There is a need for sensitive and specific blood-borne markers for the detection of gastric cancer. Raised serum macrophage inhibitory factor (MIF) levels have been proposed as a marker for gastric cancer diagnosis but, to date, studies have only encompassed patients from high-incidence areas.

METHODS

We have compared the serum concentration of MIF in a large cohort of UK and Japanese gastric cancer patients, together with appropriate control subjects (age and gender matched). Carcinoembryonic antigen and H. pylori IgG were also measured, as was DJ-1, a novel candidate protein biomarker identified by analysis of gastric cancer cell line secretomes.

RESULTS

Marked elevations of the serum concentration of MIF and DJ-1 were seen in Japanese patients with gastric cancer compared with Japanese controls, a trend not seen in the UK cohort. These results could not be accounted for by differences in age, disease stage or H. pylori status.

CONCLUSION

In regions of high, but not low incidence of gastric cancer, both MIF and DJ-1 have elevated serum concentrations in gastric cancer patients, compared with controls. This suggests that differing mechanisms of disease pathogenesis may be at play in high- and low-incidence regions.

Discovery of a tumor-specific biomarker for gastric cancer using proteomic analysis in tissue and serum

e15582

Background: Gastric cancer is curable at an early stage. However, most cases are diagnosed at an advanced stage because of the lack of screening programs. Therefore, for early detection, there is a need for serum biomarkers to be identified. Methods: We explored surface-enhanced laser desorption/ionization time-of-flight mass spectrometry to elucidate potential protein biomarkers of gastric cancer. Twenty-one resected gastric cancer samples were compared with matched adjacent normal mucosa samples. Serum from patients with gastric cancer (n=51) was compared with patients with benign gastric diseases (n=29). Samples were analyzed on Cu2+-loaded IMAC protein chips via surface-enhanced laser desorption /ionization time-of-flight mass spectrometry. Results: Comparisons of surface-enhanced laser desorption /ionization time-of-flight mass spectrometry spectra of 21 gastric cancer tissue extracts with paired adjacent normal mucosa showed a total of 56 differentially expressed protein peaks (p<0.05; Wilcoxon test). Twenty-two were up-regulated in gastric cancer tissue, whereas 34 were down-regulated. The surface- enhanced laser desorption /ionization time-of-flight mass spectrometry spectra of serum contained 130 peaks, of which 67 were significantly associated with gastric cancer (p<0.05; Wilcoxon test). We found five proteomic features (mass charge values of 2273, 3143, 3372, 3444, 3485) that were significantly up-regulated in both gastric cancer tissue and serum from gastric cancer patients. The peak intensities of tumor-specific proteomic features were used to develop a linear regression model for calculating a diagnostic index. The area under the receiver operating characteristic curve of the corresponding diagnostic index was 0.87. Conclusions: Serum biomarker panels associated with tumor tissue are capable of distinguishing gastric cancer patients from non-cancer ones.

No significant financial relationships to disclose.

Macrophage migration inhibitory factor and long-term survival in gastric cancer

e15525

Background: Our study aimed to evaluate whether pretherapeutic serum macrophage migration inhibitory factor (MIF) is an independent factor predicting long-term survival in gastric cancer. Gastric cancer is the second leading cause of cancer-related deaths worldwide, but no satisfactory tumor marker exists. We recently found serum MIF expression was progressively increased in gastric cancer. Methods: One hundred five patients, 73 men and 32 women, mean (±SD) age 63±14 years, with histologically proven gastric adenocarcinoma were included in the study. Pretherapeutic serum was collected and MIF assayed using a commercially available enzyme-linked immunosorbent assay kit. Results: Ninety-three percent of patients received curative surgery. Mean follow up was 53.5±28.3 months, and five-year survival was 65.3 percent. The mean pretherapeutic level of MIF was 72.9ng/ml (range, 2.6 to 852.1). There were no significant correlations between serum MIF level and histopathological findings (Wilcoxon test). Mean pretherapeutic levels of carcinoembryonic antigen, C-reactive protein, and albumin were 27.5ng/ml (range, 0.1 to 778 ng/ml), 0.67mg/dl (range, 0.2 to 7.82mg/dl), and 3.6g/dl (range, 2.4 to 4.4g/dl), respectively. By multivariate analysis, serum MIF was found to be an independent factor predicting long-term survival (Odds ratio, 2.84; 95% C.I. 1.27–6.68). The five-year survival rate for patients with an MIF serum level greater than 23ng/ml was 55 percent, and that for patients with an MIF serum level less than 23ng/ml was 75 percent (p=0.03; log rank test). Conclusions: The serum level of MIF is a potentially valuable pretherapeutic prognostic factor in patients with gastric cancer.

No significant financial relationships to disclose.

Fundamental role of nitric oxide in neuritogenesis of PC12h cells

1 We investigated the neuritogenic action of nitric oxide (NO)-generating agents and their mechanisms of action in a subclone of rat pheochromocytoma, PC12h cells. 2 NO donors such as sodium nitroprusside (SNP, 0.05-1 microM), NOR1 (5-100 microM), NOR2 (5-20 microM), NOR3 (5-20 microM), NOR4 (5-100 microM), or S-nitroso-N-acetyl-DL-penicillamine (SNAP, 10-100 microM) significantly induced neurite outgrowth. 3 NOR4-induced neurite outgrowth was accompanied by expression of neurofilament 200 kDa subunit (NF200) protein, an axonal marker, and was significantly inhibited by an NO scavenger, a soluble GC inhibitor, and a PKG inhibitor: 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazole-1-oxyl-3-oxide (carboxy-PTIO, 20-100 microM), 1H-[1,2,4]oxadiazolo[4,3-a] quinoxalin-1-one (ODQ, 100 microM) and KT5823 (0.2-1 microM), respectively. 4 The intracellular cGMP concentration of cells was markedly increased by treatment with NOR4 (100 microM). 5 A mitogen-activated protein kinase (MAPK) kinase inhibitor, PD98059 (10-50 microM), abolished the NOR4-induced neurite outgrowth. In agreement with this observation, NOR4 did phosphorylate extracellular signal-regulated kinase (ERK) 1 and 2, substrates of MAPK kinase. 6 A membrane-permeable cGMP analog, 8-Br-cGMP (1 mM) also induced significant neurite outgrowth. The 8-Br-cGMP-induced neurite outgrowth was almost completely inhibited by both KT5823 (0.5 microM) and PD98059 (50 microM). Moreover, sustained ERK phosphorylation was observed in the 8-Br-cGMP-treated PC12h cells. 7 These results suggest that NO itself has the ability to induce neurite outgrowth and that NO-induced ERK activation involves the NO-cGMP-PKG signaling pathway in PC12h cells.

Differences in neuritogenic response to nitric oxide in PC12 and PC12h cells

We have demonstrated that a natural iridoid compound, genipin, induces neurite outgrowth through the nitric oxide (NO)-cGMP-protein kinase G signaling pathway in PC12h cells. PC12 cells, the parental cell line of PC12h cells, have been shown to carry out neurite extension that accompanies NO production in response to nerve growth factor (NGF). This neurite outgrowth was significantly inhibited by NG-nitro-L-arginine methyl ester (L-NAME), an NO synthase inhibitor, in both PC12 and PC12h cells, suggesting that the neuritogenesis is NO-dependent in both cells. In this report, we investigated whether genipin also induces neurite outgrowth in PC12 cells in order to determine the NO-dependent neurotrophic action of genipin in more than just one cell type. Genipin induced marked neurite outgrowth in PC12h cells but not in PC12 cells. The genipin-induced neurite outgrowth was significantly inhibited by L-NAME in PC12h cells. An NO donor, NOR4, also significantly induced neurite outgrowth in a concentration-dependent manner in PC12h cells but not in PC12 cells. On the other hand, NGF-primed PC12 cells exhibited significant neurite extension, which was inhibited by L-NAME, in response to genipin. Interestingly, NGF-primed PC12 cells responded to NOR4 extending neurites and expressed detectable neuronal NO synthase protein which is not detected in naive PC12 cells. These results suggest that genipin exerts a neuritogenic action on neuronal cells which are responsive to NO itself. Furthermore, the results also suggest that PC12h cells are more suitable for the study of NO-dependent neuronal function than PC12 cells which were not responsive to NO.

Cyclic GMP-dependent neurite outgrowth by genipin and nerve growth factor in PC12h cells

We have demonstrated previously that a natural iridoid compound, genipin, induced neuritogenesis through activation of nitric oxide synthase (NOS) and mitogen-activated protein kinase (MAPK) in PC12h cells. In this paper, we investigated whether cyclic GMP (cGMP) and cGMP-dependent protein kinase (PKG) are involved in the neuritogenesis as a result of NOS activation. Furthermore, we also investigated the relationship between cGMP and MAPK activation in the signaling pathway. The genipin-induced neuritogenesis accompanied by induction of neurofilament was significantly inhibited by 1H-[1,2,4]oxadiazolo[4,3-a] quinoxalin-1-one (ODQ) and KT5823, inhibitors of soluble guanylate cyclase and PKG, respectively. Genipin-induced MAPK phosphorylation was also abolished by ODQ. These inhibitory effects of ODQ were similar to those observed for nerve growth factor (NGF)-induced neurite outgrowth and MAPK phosphorylation. The membrane-permeable cGMP analog, 8-Bromo-cGMP, had prominent neuritogenic activity, which was completely inhibited by a MAPK kinase inhibitor, PD98059. These results suggest that the soluble guanylate cyclase-PKG signaling pathway is important for MAPK activation by genipin as well as NGF during neuritogenesis in PC12h cells.

Somatic embryogenesis and plant regeneration from immature zygotic embryos of Cryptomeria japonica D. Don

This report describes the successful plant regeneration via somatic embryogenesis from immature zygotic embryos of Cryptomeria japonica D. Don. For the induction of embryogenic tissue, we determined that the optimal medium contained N6-benzyladenine and 2,4-dichlorophenoxyacetic acid. Immature zygotic embryos that were collected at the end of June yielded embryogenic tissue at the highest frequency. Embryogenic tissues that had proliferated in liquid medium included small and loosely packed cells and elongating or elongated cells. We used ten cell lines to determine the optimal medium for the development of somatic embryos. Induced somatic embryos germinated with synchronous sprouting of cotyledons, hypocotyls and roots. Gibberellin A3 in the germination medium had a positive effect on both the elongation of hypocotyls and the survival of seedlings. The frequencies of induction and germination of somatic embryos differed among the cell lines examined. Most of the seedlings grew normally. This system of somatic embryogenesis required 4-5 months for the regeneration of C. japonica plantlets from immature zygotic embryos.

Propentofylline protects beta-amyloid protein-induced apoptosis in cultured rat hippocampal neurons

beta-Amyloid protein 1-42 (beta42) can induce apoptosis in the cultured hippocampal neurons, suggesting that it plays an important role in causing neurodegeneration in Alzheimer's disease. Recently, propentofylline, a synthetic xanthine derivative, has been reported to depress ischemic degeneration of hippocampal neurons in gerbils. The present study investigated whether or not propentofylline affected the beta42-induced apoptosis of hippocampal neurons, and if so, which type of signaling machinery works in the neuroprotective action of propentofylline. Addition of propentofylline markedly attenuated the beta42-induced cell death of rat hippocampal neurons. The amyloid protein certainly induced apoptosis in the cultured hippocampal cells revealed by nuclear condensation, caspase-3 activation and an increase of Bax. Intriguingly, propentofylline blocked both the apoptotic features induced by beta42 and further induced an anti-apoptotic protein, Bcl-2, during a short time of incubation. The neuroprotective action of propentofylline was comparably replaced with dibutyryl cAMP (dbcAMP) and was completely suppressed by a low concentration of specific protein kinase A (PKA) inhibitor. Taken altogether, the data strongly suggest that the protection of propentofylline on the beta42-induced neurotoxicity is caused by enhancing anti-apoptotic action through cAMP-PKA system. Propentofylline as a therapeutic agent to Alzheimer's disease is discussed.

[Studies on the cytological function of the biomembrane and the neurons]

Na(+)-dependent and -independent transport sites were elucidated for glycine and L-leucine, respectively, in Chang liver cells, a human culture cell line. Findings of acceleration of the L-leucine uptake by the cells in the acidic medium and synchronized acidification within the cell membrane vesicles with the uptake by them all suggested contransport of L-leucine and proton and the uptake of L-leucine dependent on the inward proton gradient in Chang liver cells. Cotransport of L-leucine and proton was also demonstrated in human peripheral lymphocytes and accelerated by the addition of concanavalin A, probably accompanied by membrane hyperpolarization. It was shown that the Na(+)-gradient-dependent uptake of glycine can be regulated by insulin and 17 beta-estradiol in the rat uterus and by Ca(2+)-calmodulin and membrane potential in Chang liver cells. D-Aspartate uptake as a model of glutamate transport was characterized in rat hippocampal slices and found to consist of Na(+)-dependent (higher-affinity) and -independent (lower-affinity) components. The vulnerability of hippocampal neurons to the Alzheimer beta-amyloid protein was confirmed in vitro with primary cultured rat hippocampal neurons in the presence of the amyloid protein beta 1-42 or its core fragments. The toxicity of the amyloid protein could be blocked by the addition of insulin and several other growth factors to the medium. The addition of genipin, a plant-derived iridoid, was demonstrated to prevent the toxicity of a synthetic fragment of beta 1-42, beta 25-35. Genipin had a neuritogenic activity in PC12h cells, a rat pheochromocytoma cell line, an activity extremely sensitive to inhibitors of the nitrogen oxide (NO) synthase and soluble guanylate cyclase and an NO scavenger. It was also demonstrated in PC12h cells that the activation of the MAP kinase cascade was essential for the neuritogenesis of genipin. These properties of genipin are very comparable to those of nerve growth factor in the cells. It is considered likely that various useful, neurotrophic substances and their extracts will be found in plants in future.

Neuritogenesis of herbal (+)- and (-)-syringaresinols separated by chiral HPLC in PC12h and Neuro2a cells

Syringaresinol isolated from Epimedium koreanum NAKA1 and Magnolia officinalis REHD. et WILS. was subjected to optical resolution by chiral HPLC to give (+)- and (-)-enantiomers. The two syringaresinol enantiomers, as well as a mixture of their glucosides, showed dose-dependent neuritogenesis in a concentration range from 0.24 to 24 microM in PC12h cells.

Effect of polyacetylenes on the neurite outgrowth of neuronal culture cells and scopolamine-induced memory impairment in mice

Polyacetylenic alcohols and their linoleates isolated from Panax ginseng C. A. MEYER and Cirsium japonicum DC., of which the lipophilic extracts had been found to affect the neuritogenesis of cultured paraneurons, were demonstrated to have a significant neuritogenic effect on PC12h and Neuro2a cells. Panaxynol and the acetylenic triol in particular were highly efficient at concentrations > or = 2 microm. Panaxynol (20 mg/kg/d, i.p., for 3 d) was confirmed to improve scopolamine-induced memory deficit in mice (Y-maze task). It is suggested that the promotion of neuritogenesis in cultured paraneurons by the addition of panaxynol is related its ability to improve memory deficits in animals.

Prevention of the neurotoxicity of the amyloid beta protein by genipin

Genipin, which was shown in our previous investigation to have prominent neuritogenic activity in paraneurons such as PC12h cells, was studied to determine whether it could prevent the toxicity of Alzheimer's amyloid beta protein (Abeta) in cultured hippocampal neurons. Increased release of lactate dehydrogenase from hippocampal neurons after 2 d of Abeta25-35 administration was prevented dose dependently by the addition of genipin 20-40 microm. Morphological observations and trypan blue staining of cells confirmed the protection of hippocampal neurons from Abeta toxicity by genipin. Geniposide had less effect in preventing Abeta toxicity.

Activation of the mitogen-activated protein kinase cascade through nitric oxide synthesis as a mechanism of neuritogenic effect of genipin in PC12h cells

Prominent neurite outgrowth induced by genipin, a plant-derived iridoid, was substantially inhibited by addition of NG-nitro-L-arginine methyl ester (L-NAME), a nitric oxide (NO) synthase (NOS) inhibitor, and carboxy-PTIO, an NO scavenger, in PC12h cells. Increases of the NADPH-diaphorase activity and neuronal and inducible NOS proteins in cells preceded the neurite outgrowth after addition of genipin to medium. NO donors could induce the neurite outgrowth dose-dependently in the cells. On the other hand, an inhibitor of soluble guanylate cyclase (SGC), which is known to be a stimulatory target of NO, abolished greatly the genipin-induced neurite outgrowth. Addition of extracellular signal-regulated kinase (ERK) kinase inhibitors could almost completely abolish the neurite induction. L-NAME remarkably depressed genipin-stimulated phosphorylation of ERK-1 and -2. A neuritogenic effect of nerve growth factor (NGF) in PC12h cells was also remarkably inhibited by the NOS inhibitor, NO scavenger and SGC inhibitor. These findings suggest that induced NO production followed by cyclic GMP-mediated stimulation of the mitogen-activated protein kinase (MAPK) cascade is implicated in the neuritogenesis by genipin and NGF in PC12h cells.

Analysis of Mn(2+)/Ca(2+) influx and release during Ca(2+) oscillations in mouse eggs injected with sperm extract

Repetitive Ca(2+) release from the endoplasmic reticulum (ER) is necessary for activation of mammalian eggs. Influx and release of Mn(2+) and Ca(2+) during Ca(2+) oscillations induced by injection of sperm extract (SE) into mouse eggs were investigated by Mn(2+)-quenching of intracellular Fura-2 after adding Mn(2+) to external medium. Mn(2+)/Ca(2+) influx was detected at the resting state. A marked Mn(2+)/Ca(2+) influx occurred during the first Ca(2+) release upon SE injection, and persistently facilitated Mn(2+)/Ca(2+) influx was observed during steady Ca(2+) oscillations. As intracellular Mn(2+) concentration ([Mn(2+)](i)) increased progressively, periodic [Mn(2+)](i) rises appeared, corresponding to each Ca(2+)transient but taking a slower time course. A numerical simulation based on continuous Mn(2+)/Ca(2+) influx-extrusion across the plasma membrane and release-uptake across the ER membrane in a competitive manner mimicked well the Mn(2+) oscillations calculated from experimental data, strongly suggesting that repetitive Mn(2+) release develops after Mn(2+) entry and uptake into the ER. In other experiments, a marked Mn(2+) influx occurred upon Mn(2+) addition to Ca(2+)-free medium after depletion of the ER using an ER Ca(2+) pump inhibitor plus repeated injection of inositol 1,4,5-trisphosphate (InsP(3)). No significant increase in Mn(2+) influx was induced by injection of SE, InsP(3), or Ca(2+), when Ca(2+) release was prevented by pre-injection of an antibody against the InsP(3) receptor. We concluded that Ca(2+) influx is activated during the initial large Ca(2+)release possibly by a capacitative mechanism and kept facilitated during steady Ca(2+) oscillations. The finding that repetitive Mn(2+) release is caused by continuous Mn(2+) entry suggests that continuous Ca(2+) influx may play a critical role in refilling the ER and, thereby, maintaining Ca(2+)oscillations in mammalian fertilization.

The clinical impact of warmed insufflation carbon dioxide gas for laparoscopic cholecystectomy

BACKGROUND

Reports suggest that the insufflation of cold gas to produce a pneumoperitoneum for laparoscopic surgery can lead to an intraoperative decrease in core body temperature and increased postoperative pain.

METHODS

In a randomized controlled trial with 20 patients undergoing laparoscopic cholecystectomy, the effect of insufflation using carbon dioxide gas warmed to 37 degrees C (group W) was compared with insufflation using room-temperature cold (21 degrees C) gas (group C). Intraoperative body core and intra-abdominal temperatures were determined at the beginning and end of surgery. Postoperative pain intensity was evaluated using a visual analog scale and recording the consumption of analgesics.

RESULTS

There were no significant group-specific differences during the operation, neither in body temperature (group W: 36.1 +/- 0.4 degrees C vs group C: 35.7 +/- 0.6 degrees C) nor in intra-abdominal temperature (group W: 35.9 +/- 0.3 degrees C vs group C: 35.6 +/- 0. 6 degrees C). Postoperatively, the two groups did not differ in pain susceptibility and need of analgesics.

CONCLUSION

The use of carbon dioxide gas warmed to body temperature to produce a pneumoperitoneum during short-term laparoscopic surgery has no clinically important effect.

Flavonol glycosides from Epimedium sagittatum and their neurite outgrowth activity on PC12h cells

The MeOH extract of Epimedium sagittatum was found to show neurite outgrowth activity on cultured PC12h cells. Bioassay-guided fractionation of the MeOH extract yielded six prenylated flavonol glycosides, ikarisoside A (1), icarisid II (2), epimedoside A (3), icariin (4), epimedin B (5), and epimedokoreanoside-I (6) as the active ingredients.

Evaluation of neurotoxicity of alzheimer's amyloid beta protein (beta42) in cultured hippocampal cells and its prevention by propentofylline

Neurotoxicity of beta42 (20 microM) in cultured rat hippocampal neurons was evaluated by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction and lactate dehydrogenase (LDH) release methods as quantitative assays of cell death, and both methods indicated that propentofylline (PPF) had the ability to protect the neurons against the toxicity, although these two assay methods revealed different mechanisms for the toxic effect of beta42. Promotion of the active exocytotic system of the cells was suggested after treatment with beta42 in the MTT assay and in determination of 9-aminoacridine (AA) excretion from the preloaded cells after 24-h treatment with beta42. The promotion of AA exocytosis was blocked by the addition of PPF (20 microg/ml). The preventive effect of PPF on the neurotoxicity of beta42 has been proposed to be caused by elevation of the intracellular level of cAMP as a result of depression of the hydrolytic activity of cells.

Agrobacterium tumefaciens-mediated transformation of Robinia pseudoacacia

ROBINIA PSEUDOACACIA: (black locust) plants were regenerated after co-cultivation of stem and leaf segments with Agrobacterium tumefaciens strain GV3101 (pMP90) that harbored a binary vector that included genes for β-glucuronidase (GUS) and hygromycin phosphotransferase. Successful transformation was confirmed by the ability of stem and leaf segments to produce calli in the presence of hygromycin, by histochemical and fluorometric assays of GUS activity in plant tissues, and by Southern blotting analysis. In this transformation system, about 2 months were required for regeneration of transgenic plants from stem and leaf segments. The frequency of transformation from stem segments was approximately 24%, and the morphology of regenerated plants resembled that of the original parental strain.

Spatiotemporal analysis of Ca(2+) waves in relation to the sperm entry site and animal-vegetal axis during Ca(2+) oscillations in fertilized mouse eggs

Fertilized mouse eggs exhibit repetitive rises in intracellular Ca(2+) concentration ([Ca(2+)](i)) necessary for egg activation. Precise spatiotemporal dynamics of each [Ca(2+)](i) rise were investigated by high-speed Ca(2+) imaging during early development of monospermic eggs. Every [Ca(2+)](i) rise involved a Ca(2+) wave. In the first Ca(2+) transient, [Ca(2+)](i) increased in two steps separated by a "shoulder" point, suggesting two distinct Ca(2+) release mechanisms. The first step was a Ca(2+) wave that propagated from the sperm-fusion site to its antipode in 4-5 s (velocity, approximately 20 microm/s in most eggs). The second step from the shoulder to the peak was a nearly uniform [Ca(2+)](i) rise of 12-15 s. A slight cytoplasmic movement followed the Ca(2+) wave in the same direction and recovered in 25-35 s. These characteristics changed as follows, as Ca(2+) oscillations progressed during the second meiosis up to their cessation at the stage of pronuclei formation ( approximately 3 h after fertilization). (1) The duration of Ca(2+) transients became shorter. (2) The shoulder point shifted to higher levels and the first step occupied most of the rising phase. (3) The rate of [Ca(2+)](i) rise became greater and wave speeds increased up to 80-100 microm/s or more. (4) The transient cytoplasmic movement always resulted from the Ca(2+) wave, although its displacement became smaller. (5) The Ca(2+) wave initiation site was freed from the sperm-fusion or -entry site and eventually localized in the cortex of the vegetal hemisphere. Since the shift of the wave initiation site to the vegetal cortex is observed in fertilized eggs of nemertean worms and ascidians, this might be an evolutionarily conserved feature.

Activated Rac1 selectively up-regulates the expression of integrin alpha6beta4 and induces cell adhesion and membrane ruffles of nonadherent colon cancer Colo201 cells

Functions of small GTPases in integrin expression were investigated when the interaction of nonadherent human colon carcinoma 201 cells with the extracellular matrix (ECM) was examined. By transfection of the constitutively active form of a small GTPase Rac1, Rac V12, adhesion of cells to the ECM increased with concomitant cell spreading and formation of membrane ruffles. Activated Cdc42 and Cdc42 V12, but not wild-type Rac1, Cdc42, or RhoA, also induced the adhesion and spreading of Colo201 cells. This adhesion is integrin beta4 dependent since an antibody for integrin beta4 inhibited the RacV12-dependent cell adhesion and numbers of adhesive cells on laminin-coated plates exceeded those on collagen- and fibronectin-coated plates. By immunofluorescence, in addition to clustering of integrin molecules, expression of integrin alpha6beta4 on the cell surface of Rac V12- and Cdc42 V12-expressing cells was selectively up-regulated without an increase in biosynthesis of alpha6beta4 integrin. Treatment of Rac V12-expressing cells with wortmannin or LY294002, specific inhibitors of phosphoinositide 3-OH kinase, decreased the up-regulated alpha6beta4 and cell adhesion. In light of this evidence, we propose that the regulation of integrin alpha6beta4 expression induced by Rac1 and Cdc42 may play an important role in cell adhesion and tumorigenesis of colon carcinoma cells.

Spatiotemporal analysis of [Ca2+]i rises in mouse eggs after intracytoplasmic sperm injection (ICSI)

Intracytoplasmic sperm injection (ICSI) into mammalian eggs induces repetitive rises in intracellular Ca2+ concentration ([Ca2+]i) which are the pivotal signal in fertilization. Spatiotemporal aspects of [Ca2+]i rises following ICSI into the periphery of mouse eggs were investigated with high-speed confocal microscopy. The first Ca2+ response was generated 25-30 min after ICSI, when [Ca2+]i increased slowly and reached a certain level. The [Ca2+]i rise occurred synchronously over the ooplasm, attained the peak in 40-70 s, and lasted for 5-7 min. Succeeding Ca2+ responses occurred at intervals of 20-30 min, associated with the faster rate of [Ca2+]i rise and the shorter duration as Ca2+ oscillations progressed. The [Ca2+]i rises took the form of a wave that started from an arbitrary cortical region, but not from the vicinity of the injected sperm head. The Ca2+ wave became more pronounced and propagated across the egg faster in the later Ca2+ responses. An artifactual [Ca2+]i rise was inevitably produced during the ICSI procedure. The larger artifact affected the subsequent first Ca2+ response, resulting in the faster [Ca2+]i rise (time to peak, 10-20 s), slight spatial heterogeneity of [Ca2+]i rise in the ooplasm (but not a wave) and the shorter duration (3-4 min). The artifact slightly affected the amplitude of the second Ca2+ response, but little affected the later Ca2+ responses. It is suggested that the factor(s) that leaked out of the injected spermatozoon diffuses to a wide area and sensitizes Ca2+ channels of the endoplasmic reticulum to induce Ca2+ release synchronously over the ooplasm. The enhanced sensitization leads to propagating Ca2+ release initiated from the cortex that is more sensitive to the sperm factor.

Spatiotemporal dynamics of the [Ca2+]i rise induced by microinjection of sperm extract into mouse eggs: preferential induction of a Ca2+ wave from the cortex mediated by the inositol 1,4,5-trisphosphate receptor

Hamster sperm extract (SE) possessing Ca2+ oscillation-inducing activity was microinjected into the peripheral or central region of mouse eggs, and the first increase in intracellular Ca2+ concentration ([Ca2+]i), together with the spread of fluorescence-labeled SE in the ooplasm, was investigated by imaging with confocal microscopy. Injection into the periphery always induced a Ca2+ wave that started from the injection site after a delay of 5 to 30 s depending on the concentration of SE. The diluted SE caused a wave of two-step [Ca2+]i rises, which was always observed at fertilization. Injection into the center could induce a radial Ca2+ wave with relatively high dose of SE, but lower dose of SE caused a [Ca2+]i rise after a longer delay which was initiated synchronously over the ooplasm or was preceded in a peripheral area. Injection of diluted SE remarkably prolonged the delay time and reduced the rate of [Ca2+]i rise. The critical concentration of SE needed to induce [Ca2+]i rise was significantly lower in the periphery. These results indicate that the sensitivity to SE is higher in the cortex. SE-induced [Ca2+]i rises were blocked by an antibody against the type 1 inositol 1,4,5-trisphosphate receptor (InsP3R). The cortex was substantially more sensitive to injected InsP3 induction of Ca2+ release than the center. It is suggested that the cortex of mouse eggs may involve a functionally specialized organization of InsP3Rs and Ca2+ pools in which a cytosolic sperm factor(s) could act upon sperm-egg fusion to cause Ca2+ release, leading to the Ca2+ wave at fertilization.

Structure and transcriptional regulation of the mouse ferrochelatase gene

Ferrochelatase (EC.4.99.1.1), the final step in the biosynthesis of heme, is widely expressed in various tissues and is induced in erythroid cells. We determined the structure of the mouse ferrochelatase gene after isolation and characterization of lambda phage clones mapping discrete regions of the cDNA. The gene spans about 25 kb and consists of 11 exons. The exon/intron boundary sequences conform to consensus acceptor (GTn)/donor (nAG) sequences, and exons in the gene encode functional protein domains. The promoter region contains multiple Sp1 sites, a CACCC box and GATA-1 binding sites. Function analysis of the promoter by transient transfection assay demonstrated that one Sp1 binding site located at -37/-32 is essential for basic expression of the ferrochelatase gene in both mouse erythroleukemia (MEL) and non-erythroid EL4 cells. In addition, the region (-66/-51) containing a CACCC box and the neighboring GC box partly contributes to the inducible activity of the reporter in MEL cells upon induction with dimethylsulfoxide. It appears that at least two promoter regions of the mouse ferrochelatase gene function in basic and inducible expression.

Injection of sperm extract mimics spatiotemporal dynamics of Ca2+ responses and progression of meiosis at fertilization of ascidian oocytes

Sperm extract (SE) of the ascidian, Ciona savignyi, injected into oocytes induced repetitive intracellular Ca2+ increases with kinetics consistent with those at fertilization and caused reinitiation and progression of meiosis as in fertilized oocytes with the formation of polar bodies. The Ca2+ response comprised two sets of Ca2+ oscillations separated by 5 minutes and correlated with the first and second meiotic metaphase. The effects of SE were dose dependent and the critical dose corresponded roughly to a single spermatozoon. In the first Ca2+ transient observed by confocal microscopy, a Ca2+ wave started from the SE injection site at the peripheral region of the oocyte and propagated across the ooplasm. The similar wave was produced by injection at the central region, starting from an arbitrary cortical area after 30 seconds, probably after SE had diffused to the cortex. The sensitivity to SE is thought to be preferentially higher in the cortex. The effective component of SE was heat-unstable, and its molecular weight was estimated as in the range between 10x10(4)and 3x10(4) using membrane filters. These results suggest that, in ascidian fertilization, a cytosolic sperm protein factor is introduced to the oocyte cortex and induces Ca2+ waves and thereby meiotic resumption, leading to cell-cycle-correlated Ca2+ oscillations.

Rapid adhesion and spread of non-adherent colon cancer Colo201 cells induced by the protein kinase inhibitors, K252a and KT5720 and suppression of the adhesion by the immunosuppressants FK506 and cyclosporin A

We examined alterations in cell morphology and expression of adhesion molecules in response to a general protein kinase inhibitor K252a treatment of non-adherent colon adenocarcinoma Colo201 cells. K252a induced rapid cell adhesion and spreading with concomitant formation of actin stress fibers. A protein kinase A inhibitor KT5720 also induced cell adhesion, but the rate of spread was slower than that seen with K252a. These adhesions were mediated by integrin molecules since cell adhesion required Mg2+, Mn2+ or Ca2+, and was inhibited by monoclonal antibodies for integrins alpha2 and beta1. Indirect immunofluorescence microscopic observations revealed that integrin alpha2 and beta1 molecules in K252a-treated cells were concentrated at sites of focal adhesion, but expressions of integrin molecules were not modulated. Tyrosine phosphorylation of focal adhesion kinase (FAK) and paxillin increased during K252a- or KT5720-induced cell adhesion. Immunosuppressants FK506 and cyclosporin A suppressed the K252a-induced cell adhesion and abolished tyrosine phosphorylation of cellular proteins including FAK and paxillin. Furthermore, W7 and calmidazolium, inhibitors of calmodulin, also inhibited the cell adhesion. Based on findings that FK506 and cyclosporin A are inhibitors of the calcium calmodulin-dependent protein phosphatase, calcineurin, this phosphatase may regulate integrin-dependent cell adhesion and spread of Colo201 cells. This Colo201 cell model provides a pertinent system for studying molecules involved in signal transduction pathways and can shed light on mechanisms of metastasis and invasion of colon carcinoma cells.

[An experiment in a new method of nursing education--the problem-based learning for prenatal nursing]

At the opening of lectures in 1995 on the Science of maternity Nursing in the Special Subjects of Nursing, a problem-based learning was tried as a new educating method in the unit of "Prenatal Nursing." In the present paper, reviewing the introduction/implementation of the method, subjects in the future are described. This process contained two major flows, one was the training of tutors in problem-based learning, including participating the workshop held at McMaster University, and the other was the preparation for the class at the introduction of the new educational method, such as the overall subject composition and the development of teaching materials of prenatal nursing and resources, etc. according to the procedures of the problem-based learning. As the results of the actual implementation, various different reactions in comparison with the lecture method were observed both in tutors and students. As the subjects hereafter, the following three points have been clearly elucidated, that is, in order to proceed the problem-based learning under the present condition that it is not in the comprehensive curriculum, to prevent the overload and conflict in the student learning, considering and adjusting the relationship with contents and methods of concurrent subjects and units, to establish the system for tutorial assessment and evaluation, and to insure tutors and fulfill their training system.

Sperm-induced local [Ca2+]i rise separated from the Ca2+ wave in sea urchin eggs in the presence of a gamete fusion inhibitor, jaspisin

An increase in intracellular Ca2+ concentration ([Ca2+]i) at a focal plane was recorded simultaneously with sperm-egg binding and membrane current upon insemination of sea urchin Hemicentrotus pulcherrimus eggs. No change in current and [Ca2+]i occurred in the presence of jaspisin, a novel substance that inhibits metallo-endoproteinase and sperm-egg membrane fusion (S. Ikegami, H. Kobayashi, Y. Myotoishi, S. Ohta and K. H. Kato (1994) J. Biol. Chem. 269, 23262–23267). With low doses of jaspisin, a spermatozoon first produced a step inward current (I(on)) as an indication of gamete membrane fusion and then induced a local [Ca2+]i rise at the site of sperm attachment 6–10 seconds after I(on). The sperm, however, soon detached from the egg. Increasing inward current was abruptly cut off (I(off)) within 9–15 seconds and the local [Ca2+]i rise began to decline 1–3 seconds after I(off). In most cases, no further responses or an elevation of fertilization envelope (FE) occurred. In some cases, [Ca2+]i at the sperm attachment site increased again even after the sperm detached and triggered a Ca2+ wave which caused an activation current and FE formation. This recording of a gamete membrane-fusion-induced local [Ca2+]i rise, separated from the Ca2+ wave, is a key phenomenon for elucidating the initial sperm stimulation of the egg at fertilization.

[Report on occupational health and safety practice, level 4]

Recently, because international standardization systems have been set up in many fields, it is necessary for Japanese companies to employ persons who have specific knowledge and techniques in regards to occupational health and safety. In this paper, therefore, we discuss Occupational Health and Safety Practice, Level 4, and try to compare it with Japanese licences. The standard was developed by the Occupational Health and Safety Lead Body (OHSLB) in England. This standard is intended for occupational health and safety practitioners working in general health and safety. We conclude that the training system for occupational health and safety practitioners in Japan must be developed more fully.

Non-peptidic inhibitors of human neutrophil elastase: the design and synthesis of sulfonanilide-containing inhibitors

A novel series of pivaloyloxy benzene derivatives has been identified as potent and selective human neutrophil elastase (HNE) inhibitors. Convergent syntheses were developed in order to identify the inhibitors which are intravenously effective in an animal model. A compound of particular interest is the sulfonanilide-containing analogues. Structure-activity relationships are discussed. Structural requirements for metabolic stabilization are also discussed.

Neuritogenic effect of natural iridoid compounds on PC12h cells and its possible relation to signaling protein kinases

We examined effect of iridoid glucosides, aucubin, catalpol, geniposide and gardenoside, and their enzymic hydrolysates on neurite outgrowth of PC12h cells. Except for aucubin, these glucosides induced neurite outgrowth at 0.1 microgram/ml and above in medium after 3 d of treatment. Hydrolysates of the four glucosides all caused neuritogenesis. Geniposide hydrolysate enhanced responses of cells to carbachol and KCl-induced depolarization in terms of cytoplasmic free-calcium concentration. The aglucone of geniposide, genipin, also promoted neurite outgrowth in a dose-dependent manner (ED50 = 0.7 microM). The neuritogenic effect of genipin was partially or considerably inhibited in the presence of H-89 and genistein. All the results presented suggest that certain iridoid compounds can induce neuronal differentiation in PC12h cells through activation of components of the intracellular signal transduction pathway.

A cyclic AMP analog and high potassium prevent the death of cultured septal cholinergic neurons after nerve growth factor withdrawal

Survival, following the addition of a cAMP analog and high K+ to the medium, of cultured fetal septal cholinergic neurons was examined after nerve growth factor (NGF) deprivation. The number of acetylcholinesterase positive cells, which had progressively grown during 11-13 d of culture with NGF (50 ng/ml), was greatly reduced following 5 d of extended culture without NGF (55% of that with NGF). The degeneration of the cholinergic neurons was markedly reduced by addition of dibutyryl cAMP (dbcAMP, 1 mM), forskolin (10 microM) or KCl (15 mM) to the medium. K252b, which blocks the survival of NGF, had no effect on the action of dbcAMP. H-8 and nifedipine inhibited the survival of dbcAMP and high KCl, respectively. These results suggest that NGF, dbcAMP and high K+ promote the survival of septal cholinergic neurons acting via the receptor tyrosine kinase, protein kinase A and a Ca(2+)-dependent mechanism, respectively.

Effect on sperm-induced activation current and increase of cytosolic Ca2+ by agents that modify the mobilization of [Ca2+]i. I. Heparin and pentosan polysulfate

The mechanism of the elevation of intracellular free Ca2+ ([Ca2+]i) induced by a single sperm in eggs of the sea urchin Lytechinus variegatus was investigated. Simultaneous measurements of [Ca2+]i, and of the activation current, were carried out on eggs microinjected with Ca Green-1 or Ca Green dextran, and voltage clamped at -20 mV. The microinjection of 0.5 to 1.0 mg/ml heparin (MW 6000) or pentosan polysulfate (MW 3000), final intracellular concentration, causes a concentration-dependent inhibition in all parameters of the sperm-induced elevation of [Ca2+]i and the phase 2 calcium-activated cation current (Ip). For each: (1) the onset is delayed; (2) the rate of change is slowed; and (3) the peak amplitude attained is diminished. In some experiments at the higher concentrations, the microinjected polysulfates cause the complete suppression of the sperm-induced elevation of [Ca2+]i and Ip. The entry of multiple sperm overcomes the inhibitory effects of the polysulfates. Our data suggest that inositol 1,4,5-trisphosphate is the primary mechanism responsible for the sperm-induced release of Ca2+ from intracellular stores.

[Systemic-pulmonary artery shunt using Golaski graft: trial for measurement of the shunt flow]

For the systemic-pulmonary artery shunt operation, the modified Blalock-Taussig shunt was the first choice for procedure in our institution. Since 1990, Golaski knitted Dacron graft (4 or 5 mm in diameter) was used for the prosthesis. Ex-vivo flow calibration of the electromagnetic flow meter (Nihon Koden, MFV-3100) to Golaski graft showed good correlation between the real flow and value measured by the electromagnetic flow meter. Shunt flow was measured in the consecutive clinical fifteen cases. The shunt flow per body surface area of the patient who required additional shunt operation was 721 ml/min/m2 and one patient in whom the congestive heart failure developed after the shunt operation, had the shunt flow of 3,022 ml/min/m2. The adequate shunt flow in these cases was ranged from 745 to 2,820 ml/min/m2 (mean +/- 1 SD, 1,490 +/- 587.8). Therefore we performed the systemic-pulmonary artery shunt operation using Golaski graft to get the shunt flow of 1,000 ml/min/m2 (approximately a third of cardiac index) for the guide of good results.

Promotion of neuronal differentiation of PC12h cells by natural lignans and iridoids

We studied the effect of (+)- and (-)-syringaresinol, (+)-syringaresinol glucosides, syringin, aucubin and catalpol on neurite outgrowth of a cultured cell line of paraneuron, PC12h cells. Of these compounds, (+)-syringaresinol diglucoside and partly glucosidase-hydrolyzed aucubin were found to be the most potent in promotion of the neurite outgrowth and stimulated responses to a high concentration of KCl and to carbachol in the cells, as observed by increase of the concentration of cytosolic free calcium. It is suggested that some of these herb-derived compounds can induce neuronal differentiation in PC12h cells.

[A case of acute idiopathic mediastinitis that responded rapidly to treatment]

A 50-year-old man had a feeling of a foreign substance such as fish bone in his throat at breakfast. The feeling gradually changed to retrosternal pain and pain on swallowing, so he went to hospital, but the results of all examinations were normal. The next day he was referred to our emergency center because of the increasing pain and disturbance in swallowing. On admission he had a fever of 37.9 degrees C, a WBC of 35,000 cells/mm3, and a CRP level of 18.3 mg/dl. There was no widening of the mediastinum visible on the chest radiograph, but on the chest CT a tumorous shadow was seen around the esophagus from the cervical to the gastric portion, and was suspected to be an abscess. Some antibiotics were given, based on the diagnosis of acute mediastinitis. The pain gradually subsided, and the tumorous shadow was obscured, without mediastinal drainage. Prompt therapy resulted in rapid improvement, and the patient was discharged on hospital day 23.

Hypersensitivity pneumonitis induced by inhalation of mushroom (Pholiota nameko) spores

We describe the hypersensitivity pneumonitis of a 49-year-old woman who had been cultivating the edible mushroom 'Pholiota nameko' for three years. Her clinical manifestations and laboratory findings including transbronchial lung biopsy (TBLB) and bronchoalveolar lavage fluid (BALF) were consistent with those of other forms of hypersensitivity pneumonitis. Counter-immunoelectrophoresis determined the causative antigen to be the spores of Pholiota nameko. The indoor cultivation method appeared to play a major role in the occurrence of the hypersensitivity pneumonitis.

Moderate inhibition of mutagenicity and carcinogenicity of benzo[a]pyrene, 1,6-dinitropyrene and 3,9-dinitrofluoranthene by Chinese medicinal herbs

The activity of six Chinese medicinal herbs against the environmental mutagens and carcinogens benzo[a]pyrene (B[a]P), 1,6-dinitropyrene (1,6-diNP) and 3,9-dinitrofluoranthene (3,9-diNF) was determined. Samples of Prunella spica, Rheum palmatum, Polygonum multiflorum, Agrimonia pilosa, Ephedra sinica and Teitoutou were tested in an in vitro system. Antimutagenic activity against B[a]P was marked in the presence of extracts (boiled for 2 h in a water bath) whereas that against 1,6-diNP and 3,9-diNF varied from 20 to 86%. The differences in inhibition might be due to inactivation of metabolic enzymes. An extract of P. multiflorum was divided into ether, ethyl acetate and water soluble fractions, which were tested for antimutagenic activity against B[a]P. The antimutagenic action of the ethyl acetate soluble fraction was substantial and dose-dependent. Tannins and related compounds were the major components of the extract, of which epigallocatechin, epigallocatechin gallate, epicatechin gallate and tannic acid strongly inhibited the mutagenicity of B[a]P (2.5 micrograms/plate) in Salmonella typhimurium TA98 with S9 mix. To confirm the results of the in vitro test system, F344/DuCrj male rats were given a subcutaneous injection of B[a]P. Thereafter, they received water extracts of the six Chinese medicinal herbs for 50 weeks and were examined for tumors. The P. multiflorum extract significantly reduced the tumor incidence.

Inhibition of the nerve growth factor-induced neurite outgrowth by specific tyrosine kinase and phospholipase inhibitors

The effects of nerve growth factor (NGF) on PC12h cells have been studied with reference to the relationship between neurite outgrowth and the activities of the enzymes involved in signal transduction in the early stage of NGF action. Pretreatment of cells with selective inhibitors of tyrosine kinase (ST638 and genistein) and phospholipases C (neomycin B) and A2 (p-Bromophenacyl bromide; BPB and indomethacin) depress neurite outgrowth following 60 min treatment with NGF (0.1 microgram/ml). The inhibitor of intracellular calcium mobilization, TMB-8, also significantly depresses the NGF-induced neurite outgrowth. Arachidonic acid release, induced by NGF, from the cell lipids is reduced following previous inhibition of above mentioned enzymes. Based on these results, it is suggested that NGF requires tyrosine kinase in its early stage of action (within 60 min) in PC12h cells, phospholipases C and A2 to release Ca2+ from intracellular stores and arachidonate from cellular phospholipids, in order to induce neurite outgrowth.

Toxic effect of a beta-amyloid peptide (beta 22-35) on the hippocampal neuron and its prevention

A synthetic truncated beta-amyloid peptide, beta 22-35, was shown to have a cytotoxic effect on cultured neurons from the rat hippocampus in serum-free medium. The peptide formed aggregates and typical amyloid fibrils resembling those of the beta-amyloid protein (AP) in neutral buffer solution and showed characteristic staining with Congo red and thioflavin-S. The neurotoxicity of beta 22-35 was suppressed by addition of calf serum, dibutyryl cAMP or insulin to culture medium, but not by addition of NGF or substance P. beta 22-35 had no effect on the glial cells. These results suggest that the AP can induce neurotoxicity in the hippocampal cells in vitro and the toxicity may involve a disorder in the intracellular signal transduction.

[A case of interstitial pneumonitis associated with polymyositis complicated by renal cell carcinoma]

A 55-year-old woman was referred to the department of urology in our hospital with left renal tumor, discovered during examinations at another hospital for fever and dyspnea on exertion. Because surgery was difficult due to severe hypoxemia, pulmonary function impairment (restrictive) and bilateral diffuse interstitial shadows on chest X-ray film, the patient was referred to our department. Interstitial pneumonitis was found on transbronchial lung biopsy, and serum GOT, LDH and CPK values were elevated. These symptoms and abnormalities of laboratory data were improved by administration of prednisolone 60 mg/day, and left nephrectomy was performed without any complications. Pathological examination of the surgical specimen showed clear cell carcinoma (Grawitz). Steroid therapy was tapered off and her clinical course was good. Six months after surgery, the patient developed a recurrence of fever, which was not responsive to antibiotics. Polymyositis was diagnosed on the basis of elevated serum GOT, LDH and CPK, electromyogram and muscle biopsy findings and positive anti-Jo-1 antibody. Polymyositis/dermatomyositis is sometimes associated with interstitial pneumonitis or malignant neoplasms, but rarely with both simultaneously. Moreover, renal cell carcinoma is very rare among the malignant neoplasms associated with polymyositis/dermatomyositis, and we therefore report this unusual case.

Characterization of D-aspartic acid uptake by rat hippocampal slices and effect of ischemic conditions

The cellular uptake of D-aspartic acid (D-Asp) as a model compound for glutamic acid transport was studied in rat hippocampal slices. D-Asp is accumulated by both Na(+)-dependent and Na(+)-independent processes in hippocampal slices, and both processes are dependent on temperature. The Na(+)-dependent uptake is assumed to be high in affinity (apparent Km = 0.17 mM), but low in capacity, whereas the Na(+)-independent uptake is much lower in affinity (Km = 2.86 mM), but higher in capacity. L-Aspartic acid, L-glutamic acid, dihydrokainic acid, and threo-3-hydroxy-DL-aspartic acid markedly inhibited the uptake of D-Asp with Na+ in the medium, whereas D-glutamic acid, glycine, and L-lysine had no significant effect. The Na(+)-dependent uptake of D-Asp was significantly reduced under "hypoglycemic," "anoxic," and "ischemic" conditions, whereas the Na(+)-independent uptake was unaffected. Metabolic inhibitors such as NaCN and ICH2COOH significantly inhibited the Na(+)-dependent uptake, but not the Na(+)-independent uptake. These results suggest that the Na(+)-dependent component of D-Asp transport in rat hippocampal cells is inactivated under ischemic conditions, whereas the Na(+)-independent component is unaffected.

Separation of X- and Y-chromosome-bearing murine sperm by free-flow electrophoresis: evaluation of separation using PCR

The effectiveness of separation of murine X- and Y-bearing sperm by free-flow electrophoresis was evaluated by the polymerase chain reaction (PCR). The ratio of X- and Y-bearing sperm from cauda epididymis was analyzed before and after free-flow electrophoresis. A Y-chromosome-specific sequence (pY353/B) and an autosomal sequence (myogenin) were used to estimate the ratio between X- and Y-sperm in the separated fractions. Cauda epididymal mice sperm were separated into two peak fractions under the electric field. Each peak fraction contained sperm of normal shape, however, the motility of the sperm was extremely diminished after separation by electrophoresis. DNA was extracted from 10(4) sperm from each fraction and from the unseparated sperm, and Y-chromosome specific PCR was performed. The PCR experiment revealed that fraction No. 16 (the peak near the cathode) was a Y-sperm rich fraction, whereas fraction No. 22 (the peak near the anode) was a Y-sperm poor one. These results suggested that murine X- and Y-sperm could be successfully separated by free-flow electrophoresis. Analysis of the chromosome-specific sequence by PCR was demonstrated to be a direct and adequate method to evaluate the separation of X- and Y-sperm.

Extracellular pH modulates N-methyl-D-aspartate receptor-mediated neurotoxicity and calcium accumulation in rat cortical cultures

The effect of extracellular pH (pHo) on the excitotoxicity of N-methyl-D-aspartate (NMDA) in cultured rat cortical cells was studied. Treatment of cells with 500 microM NMDA for 15 min at various pH's in a range from 6.5 to 8.0 progressively enhanced staining with Trypan blue and release of lactate dehydrogenase with increased pH after 18 h of culture following treatment. The cytotoxic effect of high concentration of K+ (40 mM) or veratridine (10 microM) was also directly related to the increase in pHo. Free calcium accumulation in cells on addition of NMDA increased parallel to pHo. Changes in intracellular pH were estimated to be minor compared with extracellular changes. Specific NMDA antagonists could block both the NMDA- and membrane depolarization-induced neurotoxicity and calcium accumulation completely. These results suggest that the proton concentration outside of cells attenuates NMDA-induced neurotoxicity by blocking calcium accumulation.

Characterization of the uptake of adenosine by cultured rat hippocampal cells and inhibition of the uptake by xanthine derivatives

Hippocampal cells were cultured in 24-well culture plates with enriched populations of neuron or glial cells. The [3H]adenosine uptake by 7-10-day cultures of these cells was dependent on temperature, but independent of extracellular Na+. The uptake of adenosine (10 microM) for 15 s was greatly blocked by addition of 100 microM dipyridamole, 50-200 microM propentofylline or 50 microM of 2-chloroadenosine or nitrobenzylthioinosine in both cells and by 100 microM pentoxifylline in neuron. Either caffeine or theophylline (50 microM each) had no effect on the uptake by these cells. Inhibition of the adenosine uptake by propentofylline was demonstrated to be competitive in both cells.

Propagation of transient Ca2+ increase in sea urchin eggs upon fertilization and its regulation by microinjecting EGTA solution

Upon fertilization, the concentration of intracellular Ca2+ (Cai) in sea urchin eggs increased up to 3 microM when measured with fura-2, a fluorescent Ca indicator and the increase in Cai traversed from the sperm entry point as a wave over the entire egg at the mean propagation velocities of 5.0 microns/sec in C. japonicus egg and 5.3 microns/sec in H. pulcherrimus egg. However, the velocity was not uniform; i.e., it was rapid in the vicinity of the sperm entry point and the opposite point, but slow in the central region of the egg. Microinjecting a Ca-EGTA buffer and an IP3 solution into the C. japonicus egg induced the transient Cai increase more rapidly than that upon fertilization, due perhaps to the diffusion of the injectates. In order to investigate Ca2+ release during Cai increase upon fertilization, EGTA solutions were microinjected into unfertilized or fertilizing eggs. Microinjecting 100 mM EGTA (final concentration of 1 mM) not only suppressed the transient Cai increase, but also reduced the increased Cai rapidly, and never induced egg activation after insemination, whereas 10 mM EGTA (final concentration of 0.1 mM) did not significantly affect the Cai increase or the activation. Ca2+ released upon fertilization was estimated to be 150-170 microM in the egg cytoplasm from the amount of microinjected EGTA and fura-2. It was concluded that although more than 150 microM of Ca2+ was released intracellularly upon fertilization, Cai increased to only a few microM because most of the released Ca2+ was sequestered by intracellular Ca2+ binding substances.

Fluorescence characteristics of peroxidation products in porcine intestinal brush-border membranes

Treatment of the porcine intestinal brush-border membranes with 100 microM ascorbic acid and 10 microM Fe2+ in the presence of various concentrations of tert-butyl hydroperoxide (t-BuOOH) resulted in a marked fluorescence development at 430 nm, depending on the hydroperoxide concentration. This fluorescence formation was closely related to lipid peroxidation of the membranes as assessed by formation of conjugated diene. However there is no linear relation between thiobarbituric acid-reactive substances (TBARS) and fluorescence formation. On the other hand, fluorescence formation in the membranes by treatment with ascorbic acid/Fe2+ or t-BuOOH alone was negligible. The results with antioxidants and radical scavengers suggest that ascorbic acid/Fe2+/t-BuOOH-induced lipid peroxidation of the membranes is mainly due to t-butoxyl and/or t-butyl peroxy radicals. Most TBARS produced during the peroxidation reaction were released from the membranes, but fluorescent products remained in the membrane components. The fluorescence properties of products formed by lipid peroxidation of the membranes were compared with those of products derived from the interaction of malondialdehyde (MDA) or acetaldehyde with the membranes. The fluorescence products in the acetaldehyde-modified membranes also exhibited the emission maximum at 430 nm, while the emission maximum of MDA-modified membranes was 470 nm. The fluorescence intensity of MDA-modified membranes was markedly decreased by treatment with 10 mM NaBH4 but that of the peroxidized or acetaldehyde-modified membranes was enhanced by about two-fold with the treatment. In addition, a pH dependence profile revealed that the fluorescence intensity of the peroxidized or acetaldehyde-modified membranes decreases with increasing pH of the medium, whereas that of MDA-modified ones did not change over the pH range from 5.4 to 8.0. On the basis of these results, the fluorescence properties of products formed in the intestinal brush-border membranes by lipid peroxidation are discussed.

Reconstitution of the L-leucine-H+ cotransporter of the plasma membrane from Chang liver cells into proteoliposomes

L-Leucine is cotransported with H+ in the plasma membrane of Chang liver cells (Mitsumoto, Y. et al. (1986) J. Biol. Chem. 261, 4549). The leucine transport system was solubilized from the plasma membrane of the cells with ocytl glucoside and reconstituted in proteoliposomes prepared by a rapid dilution of a mixture of the solubilized proteins, octyl glucoside and liposomes. The proteoliposomes exhibited H(+)-gradient and electrical potential-stimulated leucine uptake. The H(+)-gradient-stimulated leucine uptake could be completely inhibited by carbonyl cyanide p-trifluoro-methoxyphenylhydrazone (FCCP) and 2-aminobicyclo[2,2,1]heptane-2-carboxylic acid (BCH). The stimulatory effect of H+ gradient on leucine uptake was shown to be mainly due to decrease of the Km, but not to change of the Vmax, of the transport kinetics. These results suggest that the leucine-H+ cotransporter is solubilized and reconstituted into proteoliposomes.

Protection by ethanol of cortical neurons from N-methyl-D-aspartate-induced neurotoxicity is associated with blocking calcium influx

Effect of ethanol on N-methyl-D-aspartate (NMDA)-induced neurotoxicity in rat dissociated cortical cells (8-12 day cultures) was studied. Treatment of cells with NMDA (50 and 500 microM) for 15 min caused cytotoxic effects on the cells, as examined by microscopic observations and lactate dehydrogenase release from cells 18 h after the treatment. Ca2+ is essential for these effects in medium during treatment. Presence of ethanol (50-300 mM) simultaneously with NMDA protected cells from the cytotoxicity depending on the concentration of ethanol. Calcium accumulation in cells on addition of NMDA, as monitored by fluorescence ratio (F405/F485) of Indo-1-preloaded cortical cells, was also decreased depending on the concentration of added ethanol. APV (200 microM) and ketamine (100 microM) blocked both the cytotoxicity and cellular calcium accumulation due to NMDA. These results suggest that ethanol effects its protection of neurons from NMDA-induced cytotoxicity by blocking the receptor-mediated calcium influx.