PubMed Health⌕ Search

Biomedical subjects

K Abe

Publications and source records attributed to K Abe.

At least 19 recordsLinked to original sources
PubMed1992

Different thresholds of HSP70 and HSC70 heat shock mRNA induction in post-ischemic gerbil brain.

Thresholds of induction of heat shock protein (HSP) 70 and heat shock cognate protein (HSC) 70 mRNAs after transient global ischemia in gerbil brain were investigated by in situ hybridization using cloned cDNA probes selective for each mRNA species. In sham control brain, HSP70 mRNA was little present, while HSC70 mRNA was present in most cell populations. A 0.5-min occlusion of bilateral common carotid arteries did not affect the amount of HSP70 and HSC70 mRNAs. The selective induction of HSC70 mRNA was observed in dentate granule cells at 1 h, and in most cells of hippocampus especially dentate gyrus at 3 h after 1 min of ischemia when induction of HSP70 mRNA was not evident in the identical brain. The selective induction diminished by 2 days. However, after 2 min of ischemia, HSP70 and HSC70 mRNAs were induced together in hippocampal cells from 1 h of the reperfusion, and the co-induction prolonged in CA1 cells until 2 days. Body temperatures monitored at rectum increased after the reperfusion with a peak at 30 min. The degree of increase of the body temperature was significantly higher in the case after 2-min ischemia than in the cases after 0.5- and 1-min ischemia. Although HSP70 and HSC70 mRNAs are generally co-induced in stressful conditions, our results suggest the different thresholds of the induction between HSP70 and HSC70 mRNAs after transient brain ischemia. The selective induction of HSC70 mRNA which is not accompanied by the induction of HSP70 mRNA may relate to the differences of the duration of ischemia and the degree of the increase of body temperature after ischemia.

Animals↗
PubMed1992

[Mechanism of renin release and cellular action of angiotensin II].

Renin-angiotensin (RA) system plays an important role in cardiovascular homeostasis. Here, we have described the recent progress in our study of renin release as well as the cellular action of angiotensin II. (1) Microdissection of an isolated afferent artery with or without macula densa (MD) has revealed that renin release is regulated by NaCl exposure to MD. Furosemide, prostaglandins (PGE2 and PGI2) and adenosine modulate its function. (2) Angiotensin (ang) II increases cytosolic free calcium and induces the formation of inositolphosphates in vascular smooth muscle cells. Deduced protein structure of ang II receptor (AT1-R) cDNA has indicated the presumed link of AT1-R with phospholipase C. Through the cellular action, ang II has been reported to regulate gene expression.

Adenosine↗
PubMed1992

Ras (CXXX) and Rab (CC/CXC) prenylation signal sequences are unique and functionally distinct.

Rab proteins typically lack the consensus carboxyl-terminal CXXX motif that signals isoprenoid modification of Ras and other isoprenylated proteins and, instead, terminate in either CC or CXC sequences (C = cysteine, X = any amino acid). To compare the functional relationship between the Ras CXXX and the Rab CC/CXC motifs, we have generated chimeric Ras proteins terminating in Rab carboxyl-terminal CC or CXC sequences. These mutant Ras proteins were not isoprenylated in vitro or in vivo, demonstrating that the CC and CXC sequences alone are not sufficient to replace a CXXX sequence to signal Ras isoprenoid modification. Surprisingly, chimeric Ras/Rab proteins terminating in significant lengths of carboxyl-terminal sequences from Rab1b (7-139 residues), Rab2 (5-151 residues), or Rab3a (12 residues) were also not isoprenylated. These results demonstrate that the sequence requirements for isoprenoid modification of Rab proteins are more complex than the simple tetrapeptide CXXX sequence for isoprenoid modification of Ras proteins and suggest that the Rab geranylgeranyl transferase(s) requires recognition of protein conformation to signal the addition of geranylgeranyl groups. Finally, competition studies demonstrate that a common geranylgeranyl transferase activity is responsible for the modification of Rab proteins terminating in CC or CXC motifs.

3T3 Cells↗
PubMed1992

Effects of glycine and structurally related amino acids on generation of long-term potentiation in rat hippocampal slices.

The effects of glycine and structurally related amino acids, serine, alanine and valine, on generation of long-term potentiation (LTP) of evoked potentials were investigated in the CA1, CA3 and dentate regions of rat hippocampal slices. In the Schaffer collateral-CA1 pyramidal cell synapses and in the perforant path-dentate granule cell synapses, glycine (5 x 10(-4) M) significantly enhanced the short-term potentiation (STP) induced by subthreshold tetanic stimulation, without affecting baseline responses. The effects of glycine resulted in generation of LTP in both synapses. On the other hand, glycine did not influence STP induced by subthreshold tetanus in the mossy fiber-CA3 pyramidal cell synapses. These results suggest that exogenous glycine can facilitate the generation of LTP in the CA1 region and in the dentate gyrus but not in the CA3 region. In the CA1 region and the dentate gyrus, D- and L-serine and D-alanine (10(-3) M) also showed the LTP-facilitating effects in a similar manner to glycine, but D- and L-valine had no effect on LTP generation. Furthermore, glycine and D-serine, but not L-valine, enhanced NMDA receptor-mediated synaptic responses in the absence of extracellular Mg2+. Together, these results make it probable that exogenously applied glycine and related amino acids facilitate the generation of LTP in the CA1 and dentate region by activating the glycine modulatory sites associated with NMDA receptors.

Alanine↗
PubMed1992

Selective enhancement by basic fibroblast growth factor of NMDA receptor-mediated increase of intracellular Ca2+ concentration in hippocampal neurons.

The short-term effect of bFGF on intracellular Ca2+ concentration ([Ca2+]i) of hippocampal neurons was investigated using dissociated cell cultures. Changes in [Ca2+]i were measured by microfluorometrically monitoring the fluorescence intensities from individual neurons loaded with fura-2. Perfusion of bFGF (20 ng/ml) alone did not affect the basal level of [Ca2+]i in hippocampal neurons, but clearly enhanced the [Ca2+]i increase induced by NMDA. Quisqualate or KCl-induced [Ca2+]i increase was not influenced by bFGF. These results suggest that bFGF selectively enhances the NMDA receptor-mediated response in hippocampal neurons.

Animals↗
PubMed1992

Corn kernel cysteine proteinase inhibitor as a novel cystatin superfamily member of plant origin. Molecular cloning and expression studies.

A full-length cDNA clone for a cysteine proteinase inhibitor (cystatin) was isolated from a lambda gt10 cDNA library of immature corn kernels by screening with a mixture of cDNA inserts for oryzacystatins I and II. The cDNA clone spans 960 base pairs, encoding a 135-amino-acid protein containing a signal peptide fragment. The protein, named corn cystatin I, is considered to be a member of the cystatin superfamily, since it contains the commonly conserved Gln-Val-Val-Ala-Gly region that exists in most known cystatins as a probable binding site and is significantly similar to other cystatins in its overall amino acid sequence. Corn cystatin I expressed in Escherichia coli showed a strong papain-inhibitory activity. Northern blot analysis showed that the amount of mRNA for corn cystatin I reaches a maximum 2 weeks after flowering and then decreases gradually.

Amino Acid Sequence↗
PubMed1992

Primary culture of postnatal rat hypothalamic neurons in astrocyte-conditioned medium.

Mature functional hypothalamic neurons of male and female rats (21-day postnatal) were successfully cultured without attachment to non-neuronal cells in serum-free astrocyte-conditioned medium (ACM). A novel cell-collecting method was designed for these vulnerable cells by allowing the dissociated cell suspension to stand in a vertically held, wide-tipped syringe so that the cells were concentrated near the lower liquid surface, from which position they could be easily dropped into the medium, leaving most of the small debris in the syringe. This method made it possible to study statistically the survival of cultured neurons. It was impossible to collect many viable cells by the commonly used dissociating technique for fetal rat brain. However, neuron-like cells with a few processes could be isolated from sliced hypothalamic tissues by means of enzymatic and mechanical treatments. The original processes disappeared within 1-2 days and some new processes were generated after 2-3 days in vitro; the cells survived for 28 days in vitro. The cells were identified as neurons by the immunostaining method for microtubule-associated protein 2 (MAP2) and neurofilament (NF). Such neurons were obtained from every site of hypothalamic tissue sampled. These phenomena were not observed in chemically-defined medium (CDM), CDM supplemented with basic fibroblast growth factor (bFGF), epidermal growth factor (EGF) or nerve growth factor (NGF).

Animals↗
PubMed1992

Effects of baicalein and alpha-tocopherol on lipid peroxidation, free radical scavenging activity and 12-O-tetradecanoylphorbol acetate-induced ear edema.

The effects of baicalein, a flavonoid, and alpha-tocopherol (vitamin E) on lipid peroxidation in rat forebrain homogenates, on free radical scavenging action against diphenyl-p-picrylhydrazyl (DPPH), and on 12-O-tetradecanoylphorbol acetate (TPA)-induced ear edema in mice were studied. Baicalein inhibited lipid peroxidation in forebrain homogenates, DPPH-induced free radical and TPA-induced ear edema as potently as did quercetin and nordihydroguaiaretic acid (NDGA), a lipoxygenase inhibitor, and more potently than BW755C, a mixed cyclooxygenase and lipoxygenase inhibitor. Lipid peroxidation in forebrain homogenates, DPPH-induced free radical and TPA-induced ear edema were also inhibited by alpha-tocopherol. Flavone showed no reaction. These results suggest that lipid peroxidation may play an important role in the pathogenesis of TPA-induced ear edema in mice.

Animals↗
PubMed1992

Effects of epidermal growth factor and basic fibroblast growth factor on generation of long-term potentiation in the dentate gyrus of fimbria-fornix-lesioned rats.

The effects of epidermal growth factor (EGF) and basic fibroblast growth factor (bFGF) on long-term potentiation (LTP) in the dentate gyrus in vivo were investigated in fimbria-fornix (FF)-lesioned rats. Transection of FF resulted in decreased frequency of LTP generation. Intracerebroventricular injection of EGF (50 ng) and bFGF (50 ng) significantly facilitated LTP generation in the FF-lesioned rats. These results suggest that EGF and bFGF can promote the hippocampal LTP impaired by loss of subcortical afferents.

Analysis of Variance↗
PubMed1992

Spermine facilitates the generation of long-term potentiation of evoked potential in the dentate gyrus of anesthetized rats.

The effects of the polyamines, spermine, spermidine and putrescine, on long-term potentiation (LTP) of evoked potential were investigated in the dentate gyrus of anesthetized rats. Injection of 5 nmol spermine into the lateral ventricle did not influence the basal amplitude of the population spike, but significantly enhanced the potentiation induced by subthreshold tetanic stimulation (20 pulses at 60 Hz). The effect of spermine resulted in facilitation of LTP generation. Injection of the same dose of spermidine or putrescine affected neither the basal response nor the potentiation induced by subthreshold tetanus at all, indicating that the LTP-facilitating effect is specific to spermine. Furthermore, the LTP-facilitating effect of spermine was dose-dependent in the range of 0.5-50 nmol. When 5 nmol ifenprodil, an antagonist at the polyamine site of the NMDA receptor channel complex, was concomitantly injected, spermine could not facilitate the generation of LTP. Since injection of ifenprodil alone did not influence the generation of LTP, it is probable that ifenprodil specifically blocks the effect of spermine. These results suggest that spermine facilitates the generation of hippocampal LTP, probably through an ifenprodil-sensitive polyamine site associated with the NMDA receptor.

Adrenergic alpha-Antagonists↗
PubMed1992

Distributions of heat shock protein (HSP) 70 and heat shock cognate protein (HSC) 70 mRNAs after transient focal ischemia in rat brain.

The distribution of heat shock protein (HSP) 70 and heat shock cognate protein (HSC) 70 mRNA after 30 min of middle cerebral artery (MCA) occlusion was investigated in rat brain by in situ hybridization using cloned cDNA probes selective for the mRNAs. While HSP70 mRNA was hardly present at caudate and dorsal hippocampal levels of the sham brain this mRNA was greatly induced in cells of the MCA territory 1 h after reperfusion. Although the maximum amount of induced HSP70 mRNA in the caudate was much smaller than that in the cortex the maximum induction in the caudate (3 h) preceded that in the cortex (8 h). In contrast to the case of HSP70 mRNA, HSC70 mRNA was present in most cells of the sham brain, and was especially dense in hippocampal CA3 cells. Further induction of HSC70 mRNA was observed after reperfusion in the same cell populations, as in the case of HSP70 mRNA. HSC70 mRNA levels were significantly reduced in the caudate at 8 h when small amounts of HSP70 mRNA were still elevated. In the ipsilateral granule cells of the dentate gyrus and hippocampal CA3 cells a slight but significant induction of HSC70 mRNA was observed from 1 h to 1 day, while obvious induction of HSP70 mRNA never occurred. All the induced signals of HSP70 and HSC70 mRNA were diminished or returned to the sham level by 7 days, except for HSC70 mRNA in the caudate. These results are the first observations of the distribution of HSP70 and HSC70 mRNA after transient focal ischemia of rat brain.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Epidermal growth factor selectively enhances NMDA receptor-mediated increase of intracellular Ca2+ concentration in rat hippocampal neurons.

We have previously reported that recombinant human epidermal growth factor (hEGF) facilitates induction of hippocampal long-term potentiation (LTP). In order to clarify the mechanism underlying the LTP-facilitating effect of hEGF, the influence of hEGF on intracellular Ca2+ concentration ([Ca2+]i) of hippocampal neurons was investigated using dissociated cell cultures. Changes in [Ca2+]i were measured by microfluorometrically monitoring the fluorescence intensities from individual neurons loaded with fura-2. Application of hEGF (0.6-20 ng/ml) alone did not affect the basal level of [Ca2+]i in cultured hippocampal neurons, but significantly enhanced the [Ca2+]i increase induced by L-glutamate (3 x 10(-6) M). The N-methyl-D-aspartate (NMDA) (10(-5) and 3 x 10(-5) M)-induced [Ca2+]i increase was also enhanced by hEGF, but the quisqualate (10(-7) and 3 x 10(-7) M)-induced response was not affected by the presence of hEGF. These results suggest that hEGF selectively enhances the NMDA receptor-mediated responses in hippocampal neurons. This action of hEGF may underlie the facilitation of hippocampal LTP.

Animals↗
PubMed1992

An iatrogenic foreign body (dental bur) in the maxillary antrum: a report of two cases.

Two cases of foreign bodies of the antrum are reported. One was a turbine bur which presumably entered through an oro-antral fistula after a tooth extraction. The other was also a turbine bur where the mode of entry was not clear (lack of oro-antral fistula), but it presumably entered through the socket of the extracted tooth. The mucosa of the antrum appeared normal in spite of the lengthy presence of the foreign body.

Adult↗
PubMed1992

Involvement of glycine site associated with the NMDA receptor in hippocampal long-term potentiation and acquisition of spatial memory in rats.

The effects of 7-chlorokynurenic acid (7-Cl-Kyn), a selective antagonist at the glycine site associated with the N-methyl-D-aspartate (NMDA) receptor, on hippocampal long-term potentiation (LTP) and behavioral performances in a spatial learning task were investigated. Extracellular recordings of evoked potential (population spike) were made in rat hippocampal slices. Perfusion of 7-Cl-Kyn (10(-5) M) inhibited the induction of LTP following a tetanic stimulation (51 or 101 pulses at 100 Hz) both in the Schaffer/commissural-CA1 pyramidal cell synapses and in the perforant path-dentate granule cell synapses. Acquisition of a spatial memory in the Morris water maze was examined using rats chronically cannulated for application of drugs. The intact and vehicle-injected rats learned easily to escape onto a hidden platform with short latencies, while the rats given an injection of 7-Cl-Kyn (10(-8) mol/brain, i.c.v.) prior to every session took a longer time and a longer path to escape even after all 5 sessions of trials. Injection of 7-Cl-Kyn did not affect the swimming speed, an index of swimming ability. This is the first report providing direct evidence that endogenous glycine supports the processes of learning and memory.

Animals↗
PubMed1992

Lithium chloride stimulates catecholamine synthesis and secretion in cultured bovine adrenal medullary cells.

We examined the effects of lithium treatment on the synthesis and secretion of catecholamines in cultured bovine adrenal medullary cells. The treatment of cells with lithium (0.5-4 mmol/L) for 7 days caused an increase in basal and carbachol-stimulated synthesis of 14C-catecholamines from [14C]-tyrosine but not from [14C]-DOPA. Lithium treatment (4 mmol/L, 7 days) increased the activity of tyrosine hydroxylase in the cells. Lithium treatment (2-4 mmol/L, 7 days) also enhanced the secretion of catecholamines caused by carbachol, although the carbachol-induced influx of 45Ca2+ was reduced. Lithium (4 mmol/L, 7 days) potentiated the secretion of catecholamines evoked by the Ca2+ (1 mumol/L) from cells that were permeabilized by digitonin. The activity of protein kinase C in a soluble fraction was increased in lithium-treated cells (4 mmol/L, 7 days). These results demonstrate that lithium treatment increases the synthesis and secretion of catecholamines and the activity of protein kinase C in cultured adrenal medullary cells.

Adrenal Medulla↗
PubMed1992

Inhibitory effect of oryzacystatins and a truncation mutant on the replication of poliovirus in infected Vero cells.

Poliovirus, a picornavirus family member, requires the processing of its poly-protein by its own cysteine proteinase for replication. Oryzacystatin-I and oryzacystatin-II, proteinaceous cysteine proteinase inhibitors (cystatins) of rice seed origin, were found to inhibit the replication of poliovirus effectively in infected Vero cells in vitro. Truncated oryzacystatin-I, which lacks the NH2-terminal 25 amino acid residues of the intact protein, is an even more effective inhibitor, eliciting its effect at concentrations of less than 0.25 nmol/ml. The low molecular weight cysteine proteinase inhibitors, E-64, E-64C and loxistatin, showed no anti-viral effect at any concentration investigated.

Animals↗
PubMed1992

Molecular cloning of curculin, a novel taste-modifying protein with a sweet taste.

cDNA clones for curculin, a novel taste-modifying protein, were isolated and sequenced. The encoded prepro-curculin was composed of 158 amino acid residues including a signal sequence of 22 residues and a carboxy-terminal extension peptide of 22 residues. Northern blot analysis showed that the mRNA for curculin was first detected in Curculigo latifolia fruits at 2 weeks after pollination and remained at a constant level for the following 4 weeks.

Amino Acid Sequence↗