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Biomedical subjects

T Higuchi

Publications and source records attributed to T Higuchi.

At least 181 records · Page 10Linked to original sources
PubMed2000

Oxytocin receptor gene expression in rat uterus: regulation by ovarian steroids.

The present study was designed to investigate a possible role for ovarian steroids in the regulation of rat uterine oxytocin receptor (OTR) mRNA expression before labour. By using a competitive RT-PCR system, we have previously reported that parturition was associated with high levels of uterine OTR mRNA in all the animals examined. On the other hand, near term, some rats showed high OTR mRNA levels while others did not. We therefore examined the changes in OTR mRNA expression before and during prostaglandin F(2)(alpha) (PGF(2)(alpha))-induced parturition; a paradigm adopted to reduce the variation in the onset of parturition. Injection of PGF(2)(alpha) on day 18 of pregnancy significantly increased OTR mRNA expression in all the rats within 24 h of treatment, suggesting that the variation in OTR mRNA levels during spontaneous parturition may be due to the difference in the timing of the onset of parturition. The increase in OTR mRNA was significantly abolished by injection of the anti-oestrogen compound, tamoxifen. The stimulatory action of oestrogen on OTR mRNA expression was then examined in the presence or absence of ovarian factors. Pregnant rats were ovariectomized (OVX) or sham-operated on day 18 of pregnancy and either oestrogen or vehicle was administered 6 h after the surgical operation. Oestrogen increased OTR mRNA significantly in OVX rats 18 h after administration compared with sham-operated animals. Moreover, ovariectomy alone on day 18 of pregnancy increased OTR mRNA expression to a level which reached statistical significance 24 h after the operation. In addition, oestrogen treatment increased OTR mRNA levels in OVX virgin rats in which progesterone tubes were implanted for 1 week and removed 6 h before oestrogen injection. The stimulatory effect of oestrogen was not observed in rats in which the progesterone tubes were implanted for 1 week and not removed. These results suggest that the decline of progesterone is necessary for the expression of the stimulatory effects of oestrogen on uterine OTR mRNA.

Analysis of Variance↗
PubMed2000

Evaluation of nasotracheal aspiration as a diagnostic tool for Rhodococcus equi pneumonia in foals.

The reliability of preparing bacteriological cultures from nasotracheal aspirates of foals routinely in order to diagnose R. equi pneumonia in foals was studied by isolating Rhodococcus equi from specimens obtained from 96 foals by nasotracheal aspiration with a silicon catheter. Results were compared with specimens obtained from 21 foals by transtracheal aspiration (percutaneous tracheal puncture). These 117 foals showed clinical signs of respiratory tract infection at sampling. R. equi was isolated from 14 of 21 (66.7%) specimens by transtracheal aspiration and from 59 of 96 (61.4%) specimens by nasotracheal aspiration, 649 of 655 isolates (99.1%) from the 73 positive specimens were virulent R. equi, and the culture-positive foals were diagnosed as having R. equi pneumonia. To assess the contamination of aspirates by organisms from the nasopharynx, the results of R. equi isolation from nasal swabs obtained from 56 of the 96 foals were compared to those obtained by nasotracheal aspiration from the same foals. R. equi was isolated from 2 of the 56 nasal swabs: one from a tracheal aspirate was positive, and the other was not. These results suggest that the nasotracheal aspiration technique, which is noninvasive and not associated with complications, could be used as an alternative to the transtracheal aspiration method, especially for the diagnosis of R. equi pneumonia in foals.

Actinomycetales Infections↗
PubMed2000

[Measurement of myocardial blood flow increase rate at exercise with 99mTc-tetrofosmin radionuclide angiography].

UNLABELLED: We developed new method to calculate myocardial blood flow increase rate at exercise (MBF-IR) with 99mTc-tetrofosmin (TF) radionuclide (RN) angiography and myocardial perfusion SPECT and assessed its feasibility using clinical data. METHOD: Fifteen patients who were suspected to have coronary artery disease underwent TF RN angiography and SPECT at exercise and at rest. Seven patients had coronary stenosis and eight patients had no significant coronary stenosis in coronary angiography. MBF-IRs were calculated by the following equation: [formula: see text] where Cr = regional myocardial count at rest, Ce = regional myocardial count at exercise [formula: see text] = the area under ventricular time activity curve at rest and [formula: see text] = the area under ventricular time activity curve at exercise. RESULT: Rate pressure product (RPP) was similar in patients with and without coronary stenosis (24,509 +/- 6701.9 vs. 27,196 +/- 4862.4, p = 0.39). MBF-IR was 1.88 +/- 0.73 in the area covered by stenosed coronary artery, 2.53 +/- 0.75 in unstenosed coronary artery in patients who have significant coronary stenosis and 2.97 +/- 0.77 in normal coronary patients. MBF-IRs in the area covered by stenosed coronary arteries were significantly smaller than that of normal coronary artery patient (p = 0.037). Interobserver and intraobserber reproducibility were good (r = 0.96, 0.95 respectively). There was strong positive correlation between MBF-IR and RPP in normal patients (r = 0.69, p = 0.0018), suggesting MBF increase depends on the cardiac workload. CONCLUSION: MBF-IR can be estimated by the combination of TF RN angiography and SPECT at exercise and at rest.

Aged↗
PubMed2000

Regional cerebral blood flow in the patients with depressive disorders.

Regional Cerebral blood flow (rCBF) and metabolism in major depression have been studied intently. Those studies are expected to reveal the mechanisms of the mood disorders, and also to give us valuable informations that the specific brain regions participating mood regulation. However, the data still have been inconsistent. In the present study we measured rCBF in patients with major depression and depressive state using xenon-CT CBF method. There is a tendencies that the rCBF values of normal control is the highest, and those of major depression is the lowest in most of the regions. The rCBF values in the patients with major depression are significantly lower than those in normal control in the right anterior frontal cortex, temporal cortex, putamen and thalamus. We also measured rCBF before and 90 minutes after giving calcium antagonist nilvadipine (4 mg, p.o.) in those subject. There is a tendency that nilvadipine increased in rCBF in normal control, however, it decreased in rCBF in major depression.

Adult↗
PubMed2000

Thrombopoietin enhances neutrophil production by bone marrow hematopoietic progenitors with the aid of stem cell factor in congenital neutropenia.

We examined the effects of granulocyte colony-stimulating factor (G-CSF), stem cell factor (SCF), and thrombopoietin (TPO), alone or in combination, on the generation of neutrophils by bone marrow (BM) cells from three patients with severe congenital neutropenia (SCN) through the use of a serum-deprived liquid culture system. Synergistic effects of G-CSF and SCF on the neutrophil production by BM CD34+CD38+c-kit+ cells were observed in SCN patients as well as in normal controls. The addition of TPO to the culture containing G-CSF and SCF further augmented the growth of neutrophils in the two groups. Single-cell culture experiments revealed that the three-factor combination caused increases in both the number and size of neutrophil colonies compared with G-CSF + SCF in normal BM cells, whereas only a significant increment in the colony size was observed in SCN patients. Even in the presence of SCF or SCF + TPO, the concentrations of G-CSF necessary for the substantial production of neutrophils by CD34+CD38+c-kit+ cells were higher in two patients compared with the levels obtained by normal control cells. In addition, TPO did not accelerate the maturation of neutrophilic cells supported by G-CSF + SCF. When BM CD34+CD38-c-kit+ cells were targeted, the addition of TPO to the culture containing G-CSF and SCF was required for significant neutrophil colony growth in the two groups. These results suggest that TPO enhances the G-CSF-dependent neutrophil production with the aid of SCF in this disorder.

ADP-ribosyl Cyclase↗
PubMed2000

Localization of thrombomodulin in the anterior segment of the human eye.

PURPOSE: To localize thrombomodulin (TM) in the anterior segment of the human eye. TM is a vascular endothelial cell surface glycoprotein that acts as a cofactor for the thrombin-catalyzed activation of the anticoagulant protease zymogen, protein C. METHODS: Immunohistochemical methods were used to detect TM expression in corneal epithelial cells, the lens epithelial cells, and other cells in the anterior segment of the eye. The expression of TM was also examined in cultured human corneal epithelial cells. RESULTS: TM was expressed in corneal epithelial cells, corneal endothelial cells, and nonpigmented ciliary epithelial cells, which are in direct contact with the aqueous humor. TM was also expressed in cultured corneal epithelial cells and showed cofactor activity. The amount of the antigen in the cultured corneal cells was approximately one tenth of that in human umbilical vein endothelial cells, but its specific cofactor activity (75%) was comparable to that of TM in human umbilical vein endothelial cells. The trabecular meshwork and endothelial cells lining Schlemm's canal also showed positive staining for TM. CONCLUSIONS: The TM in the cells that are in contact with the aqueous humor appears to be involved in maintaining the fluidity of the aqueous humor. In contrast, TM in cells that are not in contact with the aqueous humor may function in regulating cell proliferation and/or differentiation.

Adult↗
PubMed2000

Verotoxin-1 induces tissue factor expression in human umbilical vein endothelial cells through activation of NF-kappaB/Rel and AP-1.

This study examined the effect of verotoxin-1 (VT-1), which is released from Escherichia coli O157:H7, on endothelial expression of tissue factor (TF), a cofactor required to initiate blood coagulation. In order to elucidate the molecular basis for development of hemolytic uremic syndrome (HUS) in patients infected with E. coli O157:H7, human umbilical vein endothelial cells (HUVECs) were exposed to purified VT-1. VT-1 increased both TF activity and TF mRNA in HUVECs without loss of cell viability in a time- and dose-dependent manner from 0.1 to 10 ng/ml VT-1. Nuclear proteins extracted from VT-1-stimulated HUVECs bound to the consensus NF-kappaB/Rel and AP-1 binding oligonucleotides in a dose-dependent manner within 2 h after the stimulation in electrophoretic mobility shift assays (EMSA). Nuclear proteins from VT-1-stimulated HUVECs formed two complexes with the NF-kappaB/Rel binding motif in the human TF promoter (TF-kappaB motif). The supershift assays, using antibodies for human p65, p50 or c-Rel, indicated that the lower complex was composed of p65/p50 and the higher complex was a p65 homo- or hetero-dimer with the Rel family, except c-Rel. The human TF promoter contains two AP-1 binding sites, the proximal and distal AP-1 binding sites. The supershift assays indicated that AP-1 containing mainly c-Jun and JunD, positively bound to the proximal AP-1 motif of TF (TF-AP-1). The distal TF-AP-1 motif did not show positive binding with nuclear proteins from VT-1-stimulated HUVECs. Pretreatment of HUVECs with curcumin, an inhibitor of NF-kappaB/Rel activation, synthesis of c-Jun mRNA and binding of activated AP- I with AP-binding oligonucleotide, prevented the VT-1 induced increase in TF mRNA and activity in VT-1-stimulated HUVECs. Curcumin also inhibited NF-kappaB and AP-1 binding to TF-kappaB and proximal TF-AP-1 oligonucleotides, respectively, in a dose-dependent manner. The present work suggests that both the NF-kappaB/Rel and AP-1 activated in endothelial cells by stimulation with VT-1 binds to the TF-kappaB and proximal AP-1 binding sites, respectively, of the TF promoter.

Cells, Cultured↗
PubMed2000

[Enteral nutrition for gastrointestinal disease in home care].

We report 5 patients given enteral feeding in order to continue its nutritional supportive care of our hospital. In patients 1, 2, and 3 who were malnourished, enteral nutrition was provided due to poor oral intakes after surgical treatment. In patients 4 and 5, enteral feedings were made via the proximal jejunum in order to bypass the duodenum, for nutrients in the duodenum enhanced their biliary infection or chronic pancreatitis, respectively. All patients' nutritional status was satisfactory, but two of five patients could not be discharged from the hospital. The reason was that the patients and their families wanted to continue the hospital care in spite of the improvement in the clinical problem. They had no help at home to care for the patient. We conclude that enteral nutrition is very useful for gastrointestinal disease, but that social problems affect home care with enteral nutrition.

Aged↗
PubMed1999

Central administration of prolactin-releasing peptide stimulates oxytocin release in rats.

The prolactin-releasing peptide (PrRP) is a novel hypothalamic peptide that has been purified as a ligand of an orphan receptor which is expressed in pituitary cells, and is known to stimulate prolactin release both in vitro and in vivo. We previously determined the immunocytochemical localization of PrRP neurons in the rat brain and our results suggest that PrRP takes part in a variety of brain functions. Additionally, in rats we have demonstrated the synaptic contact of PrRP neurons with oxytocin cell bodies in the paraventricular hypothalamic nucleus (PVH) and supraoptic nucleus (SON). This observation indicates that PrRP may regulate oxytocin secretion. In the present study, we performed intra-cerebroventricular administration of PrRP to conscious rats, and examined the effect of PrRP on the plasma levels of oxytocin and vasopressin. Our results show that central administration of PrRP increased the plasma oxytocin and vasopressin levels in female rats, but in male rats only oxytocin was increased. These results suggest that the PrRP acts as a neuro-modulator of the function of magnocellular neurons, especially oxytocin neurons, in the brain.

Animals↗
PubMed1999

ASC, a novel 22-kDa protein, aggregates during apoptosis of human promyelocytic leukemia HL-60 cells.

The cytoskeletal and/or nuclear matrix molecules responsible for morphological changes associated with apoptosis were identified using monoclonal antibodies (mAbs). We developed mAbs against Triton X-100-insoluble components of HL-60 cells pretreated with all-trans retinoic acid. In particular, one mAb recognized a 22-kDa protein that exhibited intriguing behavior by forming an aggregate and appearing as a speck during apoptosis induced by retinoic acid and other anti-tumor drugs. Cloning and sequencing of its cDNA revealed that this protein comprises 195 amino acids and that its C-terminal half has a caspase recruitment domain (CARD) motif, characteristic of numerous proteins involved in apoptotic signaling. We referred to this protein as ASC (apoptosis-associated speck-like protein containing a CARD). The ASC gene was mapped on chromosome 16p11.2-12. The antisense oligonucleotides of ASC were found to reduce the expression of ASC, and consequently, etoposide-mediated apoptosis of HL-60 cells was suppressed. Our results indicate that ASC is a novel member of the CARD-containing adaptor protein family.

Amino Acid Sequence↗
PubMed1999

Fluorescent Indicators for Imaging Nitric Oxide Production.

The membrane-permeating indicator DAF-FM DA is transformed by intracellular esterases into the highly water-soluble dye DAF-FM, which traps NO produced by NO synthase (NOS) to yield a highly fluorescent triazole compound in cells (see schematic diagram). Monitoring with a fluorescence microscope should allow direct identification of intracellular production and location of NO.

Journal Article↗
PubMed1999

Novel Fluorescent Probes for Singlet Oxygen.

The first fluorescent chemical traps for (1)O(2) have been developed. DPAXs react specifically with (1)O(2) to yield the corresponding endoperoxides, DPAX-EPs (see scheme; X = H, Cl, F). DPAXs scarcely fluoresce, while DPAX-EPs are strongly fluorescent. Since the fluorescence of these probes is unaffected by H(2)O(2), superoxide, and nitric oxide, they are useful for the selective detection of (1)O(2) in biological systems.

Journal Article↗
PubMed1999

Sequence analysis of Stx2-converting phage VT2-Sa shows a great divergence in early regulation and replication regions.

In enterohemorrhagic Escherichia coli, Shiga toxin is produced by lysogenic prophages. We have isolated the prophage VT2-Sa that is responsible for production of Shiga toxin type 2 protein, and determined the complete nucleotide sequence of this phage DNA. The entire DNA sequence consisted of 60,942 bp, exhibiting marked similarity to the 933W phage genome. However, several differences were observed in the immunity and replication regions, where cI, cII, cIII, N, cro, O, and P genes were present: Predicted amino acid sequences of N, cI, cro, O and P in the VT2-Sa genome did not show significant similarity to the counterparts of the 933W genome; however its cI showed higher similarity to lambda. Furthermore, O and P closely resembled those of phage HK022. These observations suggest that the various degrees of homology observed in the immunity and replication regions of VT2-Sa could have resulted from frequent recombination events among the lambdoid phages, and that these regions play a key role as a functional unit for phage propagation in competition with other lambdoid phages.

Amino Acid Sequence↗
PubMed1999

Increased expression of zif268 mRNA in rat retrosplenial cortex following administration of phencyclidine.

Phencyclidine (PCP) has been shown to cause neurotoxicity in rat retrosplenial cortex following a single administration, although the precise mechanism underlying PCP-induced neurotoxicity is unclear. Using in situ hybridization and immunohistochemistry, we studied the effects of PCP on expression of immediate early gene zif268 mRNA and zif268 protein in the rat brain. High constitutive levels of zif268 mRNA and zif268 immunoreactivity were observed in the brain of control rats. Administration of PCP (12.5, 25 or 50 mg/kg, i.p., 6 h) caused marked induction of zif268 mRNA in the rat retrosplenial cortex, in a dose-dependent manner. However, the basal levels of zif268 mRNA in the other regions of cerebral cortex were decreased by administration of PCP. Emulsion-autoradiographical study suggested that marked expression of zif268 mRNA was observed in the layers III and IV of retrosplenial cortex where the neurotoxicity of PCP was detected. Furthermore, zif268 immunoreactivity in the layer IV of retrosplenial cortex was not changed by administration of PCP (25 mg/kg, i.p., 5 h), but that in the other layers of retrosplenial cortex was reduced by PCP. These results suggest that immediate early gene zif268 may, in part, play a role in the neurotoxicity of NMDA receptor antagonists such as PCP.

Animals↗
PubMed1999

Identification of a novel splice variant of heat shock cognate protein 70 after chronic antidepressant treatment in rat frontal cortex.

In this study, we identified a novel splice variant of 70-kDa heat shock cognate protein (HSC70), while screening differentially expressed molecules in rat brain after chronic antidepressant treatment. This clone, named HSC49, lacked 470 bp of nucleotides of rat HSC70. HSC49 encoded 442 amino acid residues with a calculated molecular mass of 48.6 kDa. DNA sequence analysis revealed that HSC49 lacked the entire Exon 7 and Exon 8 of the HSC70 gene. Chronic treatment with antidepressant, imipramine or sertraline, induced a 38.5 or 22.5% increase in mRNA levels in rat frontal cortex, respectively, when compared to controls. Western blot analysis also revealed that the protein expression of HSC49 was increased after antidepressant treatment. Our data suggest that HSC49 may be one of the common molecules induced after chronic antidepressant treatment.

Alternative Splicing↗