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Biomedical subjects

H Otani

Publications and source records attributed to H Otani.

At least 91 records · Page 5Linked to original sources
PubMed1999

Myogenic determination and differentiation of the mouse palatal muscle in relation to the developing mandibular nerve.

The vertebrate palatal muscles are derived from the cranial paraxial mesoderm and start myogenesis by the expression of myogenic regulatory factors (MRFs). Predetermined myogenic cells migrate from the cranial paraxial mesoderm into the branchial arches, followed by myogenic differentiation. The objective of this study was to elucidate whether the determination, migration, and differentiation of myogenic cells during the myogenesis of the palatal muscles, particularly the tensor veli palatini (TVP), are related to the extending mandibular nerve in mouse embryos. By immunohistochemical staining at embryonic day (E) 9.5, MyoD1 and myogenin have been expressed in the mandibular arch, into which the mandibular nerve had not yet extended. At E11.5, these myogenic cells encircled the extending mandibular nerve and were distributed from the distal and lateral to the trigeminal ganglion and into the mandibular arch to form the muscle plate, a girdle-like structure. By E12.5, these myogenic cells lost their girdle-like pattern, vacated the trunk area of the mandibular nerve, and were separated into several incompletely divided masses encircling the collateral branches of the mandibular nerve. The TVP started differentiation at E13.5 with the appearance of myofilaments and acetylcholinesterase (AchE), whereas the other palatal muscles began differentiation at E14.5. We defined the differentiation process of mouse palatal muscles into five stages based on the present findings. These results suggest that the determination and initial migration of the palatal myogenic cells into the mandibular arch occur before the mandibular nerve extends out of the trigeminal ganglion, whereas the myogenic cells migrating into the final sites of differentiation intimately relate to the extending nerve.

Acetylcholinesterase↗
PubMed1999

The vascular endothelial growth factor/fms-like tyrosine kinase system in human ovary during the menstrual cycle and early pregnancy.

In human ovaries, angiogenesis is known to be associated with the development of follicles and the formation of the corpus luteum (CL). A complex vascular network is formed within the thecal cell layer during follicular growth, and rapid neovascularization occurs toward the granulosa cell layer after ovulation. Vascular endothelial growth factor (VEGF) is a multifunctional cytokine, stimulating endothelial cell growth and enhancing microvascular permeability. A specific receptor for VEGF, fms-like tyrosine kinase (Flt-1), is expressed in vascular endothelial cells that mediates the action of VEGF. We examined the localization and expression of VEGF and Flt-1, using an immunohistochemical technique and RT-PCR analysis, in human follicles and corpora lutea during the normal menstrual cycle and early pregnancy. We measured concentrations of VEGF in extracts of human CL using an enzyme-linked immunosorbent assay during the luteal phase and early pregnancy. Immunostaining for VEGF was observed in granulosa cells from small antral follicles to preovulatory follicles. The staining was detected in thecal cells from medium-sized to preovulatory follicles. The intensity of the staining was gradually increased as a follicle grew. Flt-1 was localized in granulosa and thecal cells of preovulatory follicles as well as in endothelial cells. In the human CL, the intense staining for VEGF was observed in granulosa and thecal lutein cells, especially in the midluteal phase. The immunostaining for Flt-1 was faint in endothelial cells in the CL, whereas it was distinct in granulosa and thecal lutein cells. The concentrations of VEGF in lutein extracts were high in the early and midluteal phases and tended to decrease toward the late luteal phase. During early pregnancy, a measurable amount of VEGF was detected. RT-PCR analysis demonstrated that messenger ribonucleic acids encoding VEGF121, VEGF165, and Flt-1 were expressed in the CL. These results suggest that VEGF might have an autocrine role in the ovulatory process and luteal function as well as a paracrine role in angiogenesis.

Adult↗
PubMed1999

Hypermnesia: the role of multiple retrieval cues.

We demonstrate that encoding multiple cues enhances hypermnesia. College students were presented with 36 (Experiment 1) or 60 (Experiments 2 and 3) sets of words and were asked to encode the sets under single- or multiple-cue conditions. In the single-cue conditions, each set consisted of a cue and a target. In the multiple-cue conditions, each set consisted of three cues and a target. Following the presentation of the word sets, the participants received either three cued recall tests (Experiments 1 and 2) or three free recall tests (Experiment 3). With this manipulation, we observed greater hypermnesia in the multiple-cue conditions than in the single-cue conditions. Furthermore, the greater hypermnesic recall resulted from increased reminiscence rather than reduced intertest forgetting. The present findings support the hypothesis that the availability of multiple retrieval cues plays an important role in hypermnesia.

Adult↗
PubMed1999

Effect of vitamin E on lipid metabolism and atherosclerosis in ESRD patients.

BACKGROUND: Oxidative stress is enhanced in patients with end-stage renal disease (ESRD) undergoing hemodialysis (HD). Bioincompatibility represents an important source of reactive oxygen species. HD patients exhibit altered anti-oxidative defences and anti-oxidative vitamins such as vitamin E and C are altered in uremia. Frequently, HD patients also suffer from atherosclerotic cardiac disease. We have previously reported that low density lipoprotein (LDL) of HD patients is rich in malondialdehyde (MDA), an end product of lipid peroxidation. MDA rich LDL is thought to be an atherogenic lipoprotein due to its enhancement of macrophage foam cell formation. METHODS: We conducted a controlled study for two years comparing the effects of a vitamin E coated cellulose membrane dialyzer and an ordinary cellulose membrane dialyzer on lipid metabolism and the progress of atherosclerosis. LDL-MDA and oxidized LDL (ox-LDL) were measured in HD patients using these two types of dialyzers. Plasma vitamin E and lipid concentrations were also evaluated. The aortic calcification index (ACI) was evaluated by CT scan to assess the progress of atherosclerosis before and for every year after treatment. RESULTS: Use of a vitamin E coated cellulose membrane dialyzer for six months, one year and two years resulted in a significant reduction in LDL-MDA and ox-LDL compared to the ordinary cellulose membrane dialyzer. Treatment with a vitamin E-coated dialyzer significantly reduced the percentage increase in ACI after 24 months compared to the control. There were no significant changes in plasma vitamin E and lipid concentrations between the two groups. CONCLUSIONS: These results suggest that the oxidative stress could be one of the stimulating factors of abnormal lipid metabolism and atherosclerosis in ESRD patients.

Aged↗
PubMed1999

Involvement of MCP-1 and M-CSF in glomerular foam cell formation in ExHC rats.

BACKGROUND: An increase in glomerular macrophages (MO) is considered a potential effector mechanism by which hypercholesterolemia exacerbates glomerular injury. To investigate the mechanism underlying recruitment of MO into glomeruli, the expression of glomerular monocyte chemoattractant protein-1 (MCP-1) and macrophage colony-stimulating factor (M-CSF) mRNA were examined using a lipid-induced glomerular injury rat model. METHODS: Eight-week-old male ExHC rats, a strain susceptible to hyperlipidemia, were divided into the following 4 groups: a control group (C), a high cholesterol diet group (HH), a high cholesterol diet/standard diet group (HN), which were fed a high cholesterol diet for the first 4 weeks and a standard diet for the following 4 weeks, and a probucol-treatment group (PT). Both MCP-1 and M-CSF mRNA expression in glomeruli were analyzed using the RT-PCR method. An additional experimental group (M) fed a high cholesterol diet was administered M-CSF daily for 4 weeks. RESULTS: The expression of MCP-1 mRNA in glomeruli increased accompanied by an increased total serum cholesterol level in HH and HN. However, M-CSF mRNA expression was significantly suppressed at 1 or 2 weeks and gradually increased to almost basal levels. In the PT group, MCP-1 mRNA expression was suppressed. The early suppression of M-CSF mRNA expression was inhibited in PT. Renal histology showed a significant increase in foam cells in glomeruli in HH and HN rats at 4 weeks. HH rats showed increased and expanded foam cells at 8 weeks. In HN rats, however, foam cells decreased significantly after the transfer to a standard diet from a high cholesterol diet. The MCP-1 mRNA expression was suppressed after the transfer. In the PT group, foam cell formation was also suppressed. Foam cells were identified as MO. M-CSF-treatment significantly suppressed foam cell formation in glomeruli when compared with the untreated group levels. CONCLUSION: These findings suggest that hypercholesterolemia stimulated the expression of MCP-1 in glomeruli and attracted the MO into glomeruli. They also suggest that the reduction of hypercholesterolemia after the change in diet or treatment with probucol suppressed glomerular injury by suppressing the glomerular MCP-1 expression. M-CSF may suppress the recruitment of MO into glomeruli and foam cell formation at an early stage of hypercholesterolemia-induced glomerular injury.

Animals↗
PubMed1999

Renal expression of insulin-like growth factor-l in acute renal failure: a preliminary report.

Renal expression of insulin-like growth factor-I (IGF-I) was examined in the specimens obtained at renal biopsy from five patients with acute renal failure (ARF) at the recovering phase. IGF-I peptide and mRNA were demonstrated in the cytoplasm of the epithelial cells of focal proximal tubules in four patients in whom renal function had been ameliorating. The stainings of IGF-I peptide and mRNA were intense in patients with favorable prognosis. Either IGF-I immunoreactivity or mRNA was not detected in the renal tissues in five cases with chronic renal insufficiency and four patients with renal carcinoma. Our preliminary findings suggest that IGF-I is locally produced in the kidney during the recovery period of ARF and might play roles in the repair processes, and extend the experimental observations in animal models into human pathophysiology.

Acute Kidney Injury↗
PubMed1999

[Vitamin E disturbances in chronic renal failure].

Plasma levels of alpha-tocopherol (vitamin E) in chronic renal insufficiency (CRI) patients may be decreased, normal or elevated. However, an abnormal distribution of vitamin E in each lipoprotein has been reported. In comparison to control subject low-density lipoprotein (LDL), patient LDL contained less vitamin E. On the contrary, malondialdehyde (MDA) in patient LDL was enhanced. According to the evaluation of the susceptibility of LDL to in vitro oxidation and the rate of lipid peroxidation by fluorescence development during copper exposure, the susceptibility of patient LDL was enhanced, suggesting a possible relationship between excessive LDL peroxidation and accelerated atherosclerosis. In a clinical small uncontrolled trial, the increments of an aortic calcification index estimated by CT scan in patients treated with vitamin E were suppressed compared to those treated without vitamin E, suggesting that vitamin E might prevent the progress of atherosclerosis in CRI patients.

Humans↗
PubMed1998

Rac1 is required for the formation of three germ layers during gastrulation.

The Rac1, a member of the Rho family proteins, regulates actin organization of cytoskeleton and cell adhesion. We used genetic analysis to elucidate the role of Rac1 in mouse embryonic development. The rac1 deficient embryos showed numerous cell deaths in the space between the embryonic ectoderm and endoderm at the primitive streak stage. Investigation of the primary epiblast culture isolated from rac1 deficient embryos indicated that Rac1 is involved in lamellipodia formation, cell adhesion and cell migration in vivo. These results suggest that Rac1-mediated cell adhesion is essential for the formation of three germ layers during gastrulation.

Animals↗
PubMed1998

Cytoplasmic terminus domains of Kir6.x confer different nucleotide-dependent gating on the ATP-sensitive K+ channel.

1. In order to investigate the structural basis for the nucleotide-dependent gating of ATP-sensitive K+ channels (KATP), Kir6.1 (uKATP-1), Kir6.2 (BIR1) and chimeric channels were co-expressed with a common subtype of sulphonylurea receptor, SUR1, in COS7 cells. Representing the amino terminal domain-transmembrane domain-carboxyl-terminal domain of Kir6.1 as 1-1-1 and of Kir6.2 as 2-2-2, chimeric Kir6.x channels were constructed by swapping the amino and/or carboxyl terminal domains between Kir6.1 and Kir6.2 to give the chimeric x-1-x channels 1-1-2, 2-1-1 and 2-1-2, and the chimeric x-2-x channels 2-2-1, 1-2-2 and 1-2-1. 2. Inside-out patch clamp experiments revealed that both wild-type Kir6.1 and Kir6.2 formed inwardly rectifying K+ channels. Single-channel conductances were 36.3 and 66.1 pS, respectively. Chimeric x-1-x channels, whose transmembrane domain was that of Kir6.1, showed similar ion-pore properties to wild-type Kir6.1. Likewise, chimeric x-2-x channels had similar ion-pore properties to wild-type Kir6.2. 3. Wild-type Kir6.1 and Kir6.2 possessed distinct gating properties towards intracellular nucleotides. The activity of Kir6.1 was entirely dependent on Mg2+ and nucleotide diphosphates (NDPs) such as UDP. In contrast, Kir6.2 was activated upon excision of patch membrane. When Kir6.2 underwent rundown, UDP reactivated the channel. 4. In order to eliminate UDP dependence from Kir6.1, it was necessary to replace both N- and C-termini; chimera 2-1-2 opened in UDP-free conditions. With Kir6.2, substitution of the N-terminus with that of Kir6.1 conferred UDP dependence on chimeras 1-2-2 and 1-2-1. Chimera 2-2-1 opened in UDP-free conditions, but UDP potentiated the channel activity by > 20-fold. 5. The kinetics of UDP-dependent activation were significantly different between Kir6.1 and Kir6.2. Kir6.1 maximally activated by UDP was sensitive to intracellular ATP, although its ATP sensitivity was significantly lower than that of Kir6.2 measured in identical conditions. The kinetics of UDP-dependent activation and ATP sensitivity could be transferred between Kir6.1 and Kir6.2 only when both N- and C-termini were replaced. We therefore concluded that nucleotide-dependent gating was regulated by the N- and C-terminal domains irrespective of the transmembrane domains.

Adenosine Triphosphate↗
PubMed1998

Cystic fibrosis transmembrane conductance regulator mediates sulphonylurea block of the inwardly rectifying K+ channel Kir6.1.

1. Recombinant ATP-sensitive K+ channels (KATP channels) were heterologously expressed in the NIH3T3 mouse cell line, and the electrophysiological properties were studied using patch-clamp techniques. 2. The NIH3T3 cell lines transfected with the inwardly rectifying K+ channel Kir6.1 alone or with both Kir6.1 and cystic fibrosis transmembrane conductance regulator (CFTR) exhibited time-independent K+ currents with weak inward rectification. In contrast, no measurable K+ conductance was observed in mock-transfected cells or in cells transfected with CFTR alone. Regardless of co-transfection with Kir6.1, the transfection with CFTR produced a Cl- conductance that was activated by cell dialysis with cAMP (1 mM). The conductance was reversibly suppressed by glibenclamide (30 microM). 3. Whole-cell currents at +60 mV were blocked in a concentration-dependent manner by Ba2+ ions with similar IC50 values: 89.3 +/- 23.3 microM (Kir6.1 alone) and 67.3 +/- 24.9 microM (Kir6.1-CFTR). 4. The currents recorded from Kir6. 1-transfected cells were not affected by glibenclamide, whereas glibenclamide did inhibit the conductance expressed in cells co-transfected with CFTR (IC50 = 35.9 +/- 6.6 microM). 5. In the cell-attached mode with a 150 mM K+ pipette solution, both Kir6.1- and Kir6.1-CFTR-transfected cells displayed a class of K+ channels showing weak inward rectification and a slope conductance of 50.7 +/- 1.0 and 52.4 +/- 4.9 pS, respectively. 6. In the inside-out mode, the single-channel currents recorded from both types of cells were not inhibited by intracellular ATP (1 mM). However, glibenclamide was found to block the single-channel activities in the co-transfected cells.

3T3 Cells↗
PubMed1998

[One stage operation for aneurysm of the diverticulum of the ductus arteriosus and coronary artery bypass grafting].

Aneurysm of the diverticulum of the ductus arteriosus in the adult is rare. One stage operation for aneurysm of the diverticulum of the ductus arteriosis and coronary artery bypass grafting (CABG) is reported. A 61-year-old man was admitted for diagnosis of thoracic aneurysm on chest X-ray and CT. Chest CT scan showed an aneurysm above the left main pulmonary artery. An aortography showed the left vertebral artery originated directly from the aortic arch and a saccular aneurysm arising from the aortic isthmus and lesser curvature of the aortic arch. Coronary arteriography showed 75% stenosis at the right coronary artery (seg. #1) and 75% stenosis at the left anterior descending artery. Operation was performed through a median sternotomy. The aneurysm of 6 to 3 cm was located between the aortic isthmus and left pulmonary artery. Ascending aorta and right atrium were used to institute cardiopulmonary bypass (CPB). CABG (LITA to #7, SVG to #4 PD) was performed. Arterial cannulation was then switched to the left femoral artery. The proximal aorta was cross-clamped between the left vertebral artery and the left subclavian artery under the partial CPB, and the distal aorta was occluded with a occulusive balloon catheter via the right femoral artery. The selective left axillar artery cannulation was performed to perfuse LITA. The aneurysm was resected and closed with a patch. His post-operative course was uneventful.

Aortic Aneurysm↗
PubMed1998

A novel Drosophila nuclear protein serine/threonine kinase expressed in the germline during its establishment.

Nuclear protein kinases are believed to play important roles in regulating gene expression. We report here the identification and developmental expression of Dmnk (Drosophila maternal nuclear kinase), a Drosophila gene encoding a putative nuclear protein serine/threonine kinase with no apparent homology to previously identified protein kinases and located at 38B on the second chromosome. Dmnk mRNAs are transcribed in nurse cells and are subsequently localized in the anterior of oocytes during oogenesis, in a manner similar to several maternal transcripts regulating oogenesis and early embryogenesis. At early cleavage-stages Dmnk transcripts are transiently present throughout the embryo, but become restricted to the posterior pole and then to the newly-formed primordial germ cells (pole cells) by the blastoderm stage. The transcripts are sustained in the pole cells during gastrulation until they pass through the midgut pocket wall into the body cavity. Immunostaining with specific antibodies revealed that Dmnk proteins are localized to the nuclei in a speckled pattern. Dmnk proteins become detectable in both somatic and germ line cell nuclei upon their arrival at the periplasm of the syncytial embryo, but then disappear from the somatic cell nuclei. Consistent with mRNA expression, Dmnk proteins in pole cell nuclei are sustained during gastrulation. Taken together, Dmnk represents a novel class of nuclear protein kinases and the dynamic expression of Dmnk suggests a role in germ line establishment. The results are discussed in the light of recent findings concerning germ line establishment in Caenorhabditis and Drosophila.

Alternative Splicing↗
PubMed1998

Identification of a phosphopeptide in bovine alpha s1-casein digest as a factor influencing proliferation and immunoglobulin production in lymphocyte cultures.

Digestion of bovine alpha s1-casein with bovine trypsin produced peptide(s) with an inhibitory effect on concanavalin A-induced proliferation of mouse spleen cells. One of these peptides was isolated from the alpha s1-casein digest following ultrafiltration, hydroxyapatite chromatography and reversed-phase HPLC, and amino acid composition and sequence analyses showed it to be sequence 59-79 from the phosphoserine-rich region of alpha s1-casein. The isolated peptide significantly inhibited the concanavalin A-induced proliferation of mouse spleen cells and rabbit Peyer's patch cells, whereas it enhanced the lipopolysaccharide- and phytohaemagglutinin-induced proliferation of both cells. The peptide displayed mitogenic activity in the cell cultures without the commercial mitogen, and significantly enhanced immunoglobulin production. Moreover, residues 1-25 from the phosphoserine-rich region of bovine beta-casein had a similar effect on the proliferation of mouse spleen cells and rabbit Peyer's patch cells stimulated or not stimulated by the commercial mitogen. These results indicate that caseinophosphopeptides may act as a humoral immunostimulator in cell cultures.

Amino Acid Sequence↗
PubMed1998

Hypermnesia for prose.

Hypermnesia is an improvement in memory that occurs with repeated testing. In the present experiment, hypermnesia was examined with prose materials. Participants were presented with either a fairy tale or an expository passage, followed by 3 free-recall tests. Participants used 1 of 2 encoding strategies (the relational or item-specific processing conditions) to process the material, or they simply read the material (the read-only condition). Recall performance improved across the 3 tests in the relational and item-specific processing conditions. No improvement was found in the read-only condition.

Adult↗
PubMed1998

Photoallergenicity of a fluoroquinolone antibacterial agent with a fluorine substituent at the 8-position in guinea pigs exposed to long-wavelength UV light.

The 8-position of the quinolone ring of balofloxacin (BLFX), one of fluoroquinolones, was replaced with fluorine to obtain the 8-F. When an aqueous solution of bovine serum albumin (BSA) containing the 8-F was exposed to long-wavelength UV light (UVA) at a rate of 2.5 J/cm2, the absorbance of BSA at 300 nm or longer wavelengths increased markedly in comparison to that of native BSA. In addition, when a homogenate of skin tissue from Hartley guinea pigs was exposed to UVA (2.5 J/cm2) in the presence of the 8-F and then injected subcutaneously into guinea pigs, the animals produced IgG class antibody specific to the 8-F and its UVA-irradiation product. No such phenomenon, however, was observed when the parent compound, i.e. , BLFX which possesses a methoxy group at the 8-position, was used instead of the 8-F. In a subsequent experiment, the 8-F was administered either orally or topically to the shaved neck of guinea pigs and then irradiated with UVA (5 J/cm2) once daily for 5 days. When the treated animals were challenged by a combination of UVA irradiation (5 J/cm2) and either an oral or intradermal administration of the 8-F, 2 and 3 of the 5 animals showed redness and erythema on the irradiated area, respectively. However, no change was observed when BLFX was used instead of the 8-F. These results suggest that the introduction of a fluorine substituent to the 8-position of quinoline ring of fluoroquinolones induces photoallergic responses in which the fluoroquinolone or its photo-denatured product(s) act as an allergen.

Animals↗
PubMed1998

Induction of ectopic corticotropic tumor in mouse embryos by exo utero cell transplantation and its effects on the fetal adrenal gland.

To establish an in vivo experimental system for developmental endocrinology research, AtT-20 cells, a corticotropic tumor cell line, were transplanted by exo utero manipulation into mouse embryos on embryonic day 14. The induced tumor secreted ACTH in situ, and the circulating ACTH level was elevated. This was the first model for studying the regulation of ACTH in the mouse fetal adrenal in vivo and the first continuous ACTH treatment model in rodent fetuses. The changes in the adrenal gland from the tumor-induced embryos were analyzed by light microscopic morphometry, immunohistochemistry for steroidogenic enzymes, and electron microscopy. In the treated adrenal, the volume of the inner cortical zone was significantly larger than that in controls. In the inner zone, cell density was decreased, and average cell size was increased, whereas bromodeoxyuridine-incorporation was not increased. The enlarged inner zone cells expressed an enhanced level of cytochrome P45011beta, the corticosterone-synthesizing enzyme, and the serum corticosterone level was increased. Electron microscopy showed an active form of the organelles involved in steroidogenesis. These findings indicate that ACTH stimulates both adrenocortical hypertrophy and steroidogenesis in fetal mice. Potential perspectives of the novel paradigm in this research for molecular developmental endocrine study are discussed.

Adrenal Glands↗
PubMed1998

Primary pulmonary artery sarcoma.

A 66-year-old woman with a history of mitral valve replacement with a Starr-Edwards ball valve 25 years ago was treated for refractory heart failure but died of right heart failure. At autopsy, primary pulmonary artery sarcoma was found in the right ventricular outflow tract, main pulmonary trunk, and bilateral pulmonary artery, and had invaded the aortic arch. The pathohistologic diagnosis was osteosarcoma. Echocardiography, chest computed tomography and right ventriculography performed 1 year before death did not reveal the presence of a tumor in the pulmonary artery. The history of this patient shows that primary pulmonary artery sarcoma grows rapidly, with, in this case, the patient dying within 1 year of its appearance.

Aged↗