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H Okamoto

Publications and source records attributed to H Okamoto.

At least 73 records · Page 4Linked to original sources
PubMed2003

Effects of G-protein-specific antibodies and G beta gamma subunits on the muscarinic receptor-operated cation current in guinea-pig ileal smooth muscle cells.

(1) The effects on the whole-cell carbachol-induced muscarinic cationic current (mIcat) of antibodies against the alpha-subunits of various G proteins, as well as the effect of a Gbetagamma subunit, were studied in single guinea-pig ileal smooth muscle cells voltage-clamped at -50 mV. Ionized intracellular calcium concentration, [Ca(2+)](i), was clamped at 100 nM using a 1,2-bis(2-aminophenoxyl-ethane-N,N,N',N'-tetraacetic acid)/Ca(2+) mixture. (2) Application of ascending concentrations of carbachol (1-300 micro M) activated mIcat (mean amplitude 0.83 nA at 300 micro M carbachol; EC(50) 8 micro M; Hill slope 1.0). A 20 min or longer intracellular application via the pipette solution of G(i3)/G(o) or G(o) antibodies resulted in about a 70% depression of the maximum response without change in the EC(50) value. In contrast, antibodies against alpha-subunits of G(i1), G(i1)/G(i2), G(i3), G(q)/G(11) or G(s) protein over a similar or longer period did not significantly reduce mIcat. Antibodies to common Gbeta or infusion of the Gbetagamma subunit itself had no effect on mIcat. (3) If cells were exposed briefly to carbachol (50 or 100 micro M) at early times (<3 min) after infusion of antibodies to Galpha(i3)/Galpha(o) or to Galpha(o) had begun, carbachol responses remained unchanged even after 20-60 min; that is, the depression of mIcat by these antibodies was prevented. (4) These data show that Galpha(o) protein couples the muscarinic receptor to the cationic channel in guinea-pig ileal longitudinal smooth muscle and that Gbetagamma is not involved. They also show that prior activation of the muscarinic receptor presumably causes a long-lasting postactivation change of the G protein, which is not reflected in mIcat, but acts to hinder antibody binding.

Animals↗
PubMed2003

Bypass balloon pumping: a newly developed device for mechanical circulatory support in heart failure.

Various types of assist devices have been developed for severe heart failures. Among them, intra-aortic balloon pumping (IABP) has achieved popularity, mainly in the treatment of patients with either severe cardiac infarction or low cardiac output syndrome (LOS) after open-heart surgery. However, IABP has a limitation in that although it acts as a pressure support, it cannot directly support flow volume. In cases of severe pump failure, stronger pump support would be required. However, there is a limit in the clinical use of temporary mechanical support using a pump because of the costs of the expensive equipment. With this in mind, we came up with a new idea in which the motion of a balloon in IABP system is converted into a power source for creating a one-way stream. In order to realize our idea, we made a J-shaped sample model of pulsating chamber incorporating two ball valves. In the hydrodynamic experiment using our new device, flows over 2500 ml/min (Max. 3475 ml/min) were obtained. The percent changes in parameters such as TTI, DPTI and bypass flows obtained by the experiment of left ventricular bypass have demonstrated that our assist system is effective for reducing cardiac work.

Animals↗
PubMed2003

[Sequential bypass grafting with arterial grafts can be functioned? Assessment of evaluation for function of sequential bypass grafting from theoretical model].

As total arterial revascularization in coronary artery bypass grafting (CABG) has been recommended, a sequential bypass technique using arterial grafts has been induced. We evaluate whether a sequential bypass graft can be functioned or not by using a simple simulation model for coronary circulation analogous to the electrical circuit based on Ohm law. The ratio of flow between graft and native coronary artery was determined by the severity of stenosis in the bypassed vessels and the graft diameter. In selection for sequential bypass technique, these factors should be taken into consideration.

Arteries↗
PubMed2003

Emergency CT scan for the diagnosis of superior mesenteric artery embolism. Report of 2 cases.

Two patients with superior mesenteric artery embolism are presented. In both cases, contrast-enhanced computed tomography (CT) demonstrated enhancement of the superior mesenteric artery roots and non-enhanced filling defect in the more distal part of the artery. Immediate extraction of the embolus saved 1 patient but massive bowel resection was necessary in another. Mesenteric arteriography has been the golden standard for the diagnosis of mesenteric occlusion, but it is usually time-consuming and not universally available. On the other hand, CT equipment is in widespread use and the examination can be performed much more easily. Patients with unexplained acute abdominal pain should undergo CT examination and be screened for mesenteric arterial occlusion.

Aged↗
PubMed2002

Autoimmunity to CD38 and GAD in Type I and Type II diabetes: CD38 and HLA genotypes and clinical phenotypes.

AIMS/HYPOTHESIS: Autoantibodies against CD 38 have been found in some patients with Type II (non-insulin-dependent) diabetes mellitus and have been shown to stimulate insulin secretion by cultured human islets. We tested whether this new form of autoimmunity, (i). overlaps with anti-GAD autoimmunity, (ii). identifies an insulin-deficient phenotype, (iii). is under the influence of genetic factors. METHODS: We screened 496 adults by immuno-blot analysis in the Botnia Study (298 with Type II and 98 with Type I (insulin-dependent) diabetes mellitus, 100 non-diabetic control subjects). RESULTS: CD 38-autoantibodies were found in 8.4% of Type II diabetic patients ( p<0.003 vs 0% of control subjects), particularly in anti-GAD positive (14% vs 6% of anti-GAD negative, p=0.0004). CD 38 ab were also found in 4% of Type I diabetic patients; in the whole study group, 59% of anti- CD 38 positive had DQB1*02 compared with 38% of anti-CD 38 negative ( p=0.04). On the OGTT, beta-cell function (as the ratio of insulin-to-glucose areas) was impaired ( p=0.02) only in association with anti-GAD positivity (3.2+/-3.1 U/mol, mean +/- SD) but not in anti- CD 38 positive patients (5.6+/-2.9) as compared with patients free of autoimmunity (4.5+/-4.6, p=NS). In 44 Type II diabetic patients (22 negative and 22 positive for anti- CD 38), no mutations were detected in any of the 8 exons, 5' end of intron 1 or the 5' and 3' untranslated regions of the CD 38 gene. The previously described missense mutation (Arg140Trp) in exon 3 was not found in this cohort. There was no association between the PvUII polymorphism and clinical phenotype. CONCLUSION: Anti-CD 38 autoimmunity identifies a clinical phenotype similar to non-autoimmune Type II diabetes, with relative preserved beta-cell function and weak genetic influence.

ADP-ribosyl Cyclase↗
PubMed2002

Hand-assisted laparoscopic hepatic resection.

Thanks to recent advances, performance of liver resection is now possible using laparoscopic procedures. However, still there are some difficulties to overcome. The hand-assisted method lends safety and reliability to the laparoscopic procedure. A 54-year-old man diagnosed with hepatocellular carcinoma (HCC) was referred for hepatectomy. Angiography with computed tomography (CT) scans revealed a 2-cm hepatocellular carcinoma (HCC) at segment V, close to the gallbladder. A hand-assisted laparoscopic hepatic resection was performed. Four 10-mm trocars, one for wall lifting and three for working, were placed in the upper abdomen. A small incision was added at the right side of umbilicus, and the operator's left hand was inserted through it. A microwave tissue coagulator and laparoscopic ultrasonic dissector were used for liver resection. Total operation time was 162 min; blood loss was 20 g. The postoperative course was uneventful, and the postoperative hospital stay was 7 days. We thus demonstrated that laparoscopic liver resection is safer and easier when the hand of the operator can be inserted into the abdomen. The small incision does not greatly diminish the benefits that accrue from minimally invasive laparoscopic surgery. The hand-assisted procedure allows better access to the tumor. In addition, hand assistance restores the sense of touch to the operator and is an effective means of controlling sudden and unexpected bleeding.

Angiography↗
PubMed2002

Tuning of electronic structures of quasi-one-dimensional bromo-bridged Ni(III) complexes with strong electron-correlation by doping of Co(III) ions, [Ni(1-x)Co(x)(Chxn)(2)Br]Br(2).

We have succeeded in synthesizing the Ni(III) complexes doped by Co(III) ions, [Ni(1-x)Co(x)(chxn)(2)Br]Br(2) (x = 0, 0.043, 0.093, and 0.118) by using an electrochemical oxidation method. The single-crystal reflectance spectrum of x = 0.118 shows an intense CT band about 0.5 eV, which is lower than that of [Ni(chxn)(2)Br]Br(2) (1.3 eV). The single-crystal electrical conductivities at room temperature of these compounds increase with increase of the amounts of doping of Co(III) ions. In the ESR spectra, peak-to-peak line widths DeltaH(pp) at room temperature change about 600 G in [Ni(chxn)(2)Br]Br(2) to 200 G in x = 0.118. Such a large x dependence of DeltaH(pp) seems to be ascribed to the increasing contribution from the increasing Curie spins which have smaller line width. Therefore, we have tuned the electronic structures of quasi-one-dimensional bromo-bridged Ni(III) complexes with strong electron correlations by doping of Co(III) ions.

Journal Article↗
PubMed2002

Ultrafast optical switching from an ionic to a neutral state in tetrathiafulvalene-p-chloranil (TTF-CA) observed in femtosecond reflection spectroscopy.

Ultrafast optical switching from an ionic ( I) to a neutral ( N) state in TTF-CA was observed in femtosecond reflection spectroscopy. Charge transfer excitation in the I phase produces N donor ( D0) acceptor ( A0) strings within 2 ps. These initial N states decay with a lifetime of 300 ps at 4 K, but rather multiply leading to macroscopic I-N conversion within 20 ps at 77 K just below the N-I transition temperature T(NI). Near T(NI), we also found the evidence for the coherent motion of the macroscopic N-I domain boundary with a period of 85 ps.

Journal Article↗
PubMed2002

Analysis of the entire genomes of thirteen TT virus variants classifiable into the fourth and fifth genetic groups, isolated from viremic infants.

TT virus (TTV) DNA in serum samples obtained from 24 TTV-infected infants was amplified by polymerase chain reaction (PCR) with inverse primers derived from the untranslated region. The amplified PCR products were molecularly cloned; six clones each were analyzed. Seventy-six (53%) of the 144 TTV clones were classified into group 4 (YONBAN isolates), and 22 (15%) into a novel genetic group (group 5). The TTV clones in group 4 were classified into 9 types, and those in group 5 into 4 types. The entire nucleotide sequence of one representative clone each from the 13 types were determined; they comprised 3570-3770 nucleotides, and had poor homology to TTVs of groups 1-3 (TA278, PMV and SANBAN isolates). A phylogenetic tree based on the entire nucleotide sequence of open reading frame 1 confirmed the presence of five distinct clusters separated by a bootstrap value of 100%. Analysis of 13 TTV variants demonstrated preservation of the genomic organization and transcription profile in all TTV groups. TTV group 4 was detected in 54% or 72% of 7-to-12-month-old infants in Japan and China, respectively, which is comparable with that among adults in the respective country, indicating early and frequent acquisition of this TTV group in infancy.

Adult↗
PubMed2002

Intrathecal fentanyl/meperidine combined with low-dose epidural bupivacaine for Cesarean section in a patient with advanced Krukenberg tumors.

This case report demonstrates the anesthetic management of a 41-year-old primiparous parturient with massive ascites due to advanced Krukenberg tumors, undergoing Cesarean section. We chose a combined intrathecal-epidural technique, using intrathecal hypobaric fentanyl and hyperbaric meperidine, and a low dose of epidural bupivacaine in order to avoid hemodynamic instability in this critically ill patient. Surgery was carried out without difficulty under adequate regional anesthesia. The blood pressure was maintained with low doses of phenylephrine and dopamine. Opioid-related complications such as nausea-vomiting, pruritus, drowsiness, and respiratory depression were not observed in this patient. Therefore, intrathecal opioids combined with a low dose of epidural local anesthetics for Cesarean section is suitable for critically ill patients with malignant abdominal tumors, such as a Krukenberg tumor, complicated by massive ascites.

Adjuvants, Anesthesia↗
PubMed2002

Continuous spinal analgesia for labor and delivery in a parturient with hypertrophic obstructive cardiomyopathy.

Induction of labor under analgesia was planned for a 30-year-old-primiparous patient with hypertrophic obstructive cardiomyopathy (HOCM), as her fetal evaluation revealed intrauterine growth restriction at 38 weeks' gestation. However, regional analgesia during labor may present a potential risk for hemodynamic instability in patients with HOCM due to the possibility of a sympathetic block, as a result of vasodilation associated with the administration of local anesthesia. This case report demonstrates the successful management of the patient with analgesia provided by a continuous spinal catheter dosed with a continuous infusion of fentanyl and supplemental meperidine. Fetal surveillance monitoring included fetal pulse oximetry in addition to conventional cardiotocography, on the basis of which cesarean section was avoided.

Adult↗
PubMed2002

Chronic actinic dermatitis developed during phototherapy for psoriasis.

A patient with psoriasis vulgaris had been successfully treated with PUVA and UVB therapy. During maintenance phototherapy, he suddenly became photosensitive and developed eczematous eruption. Minimal response doses to UVB and UVA were extremely low--1.09 mJ/cm2 and 0.3 J/cm2, respectively. No chemical substances were identified as the responsible photosensitizer. The condition was diagnosed as chronic actinic dermatitis (CAD). PUVA therapy was unsatisfactory because it was not possible to administer an adequate dose of UVA. Oral cyclosporine, topical corticosteroid and sunscreen were used with beneficial therapeutic effects on psoriasis and CAD. As far as we know, the development of CAD during phototherapy has not been previously reported.

Chronic Disease↗
PubMed2002

Muscarinic agonist potencies at three different effector systems linked to the M(2) or M(3) receptor in longitudinal smooth muscle of guinea-pig small intestine.

1. The abilities of muscarinic agonists (arecoline, bethanechol, carbachol, McN-A343, methacholine, pilocarpine) to inhibit isoprenaline-induced cyclic AMP production in chopped fragments (via M(2) receptors), and to evoke cationic current (I(cat)) (via M(2) receptors) or calcium store release (via M3 receptors) in enzyme-dispersed, single voltage-clamped cells from longitudinal smooth muscle of the guinea-pig small intestine were examined. 2. All muscarinic agonists (1 - 300 microM) examined inhibited isoprenaline (1 microM)-induced accumulation of cyclic AMP, the IC(50) varying from 52 to 248 microM. However, their relative potencies to evoke this M(2) effect were not significantly correlated with their ability to evoke I(cat), also a M(2) effect, whether or not calcium stores were depleted; pilocarpine and McN-A343 inhibited the I(cat) response to carbachol. 3. Muscarinic agonists (concentration 300 or 1000 microM), except pilocarpine and McN-A343 which were ineffective, evoked Ca(2+)-activated K(+) current (I(K-Ca)) resulting from Ca(2+) store release (M(3) effect). Their effectiveness was tested by estimating residual stored calcium by subsequent application of caffeine (10 mM). The relative potencies to evoke Ca(2+) store release (M(3)) and for I(cat) activation (M(2)) were closely correlated (P<0.001). 4. These data might be explained if M(2)-mediated adenylyl cyclase inhibition and I(cat) activation involve different G proteins, or involve different populations of M(2) receptors. The observed correlation of agonist potency between I(cat) activation and Ca(2+) store release supports the proposal (Zholos & Bolton, 1997) that M(3) activation can potentiate M(2)-cationic channel coupling through Ca(2+)-independent mechanisms.

Animals↗
PubMed2002

CD161+ T (NT) cells exist predominantly in human intestinal epithelium as well as in liver.

It has been reported that human CD161 (NKR-P1A)+ T cells are counterparts of murine natural T (NT) cells and predominantly accumulate in the liver. However, NT cells in the human intestine have not been well analysed. The aim of this study was to assess the existence of NT cells in human intestinal epithelium and determine their phenotypical characterization. Intra-epithelial lymphocytes (IEL) were isolated from surgical specimens (jejunum, ileum and colon). The surface phenotype of IEL was analysed using a FACScan and compared with that of mononuclear cells (MNC) from other organs. CD161+ T cells were abundant in human intestinal epithelium as well as the liver. The majority of CD161+ T cells in IEL were CD8+ cells. About 50% of CD161+ T cells in hepatic lymphocytes (HL) expressed CD56, whereas only 14% of CD161+ T cells in IEL expressed CD56. The jejunum showed the greatest abundance of CD161+ T cells among the intestinal regions investigated. These results suggest that CD161+ T (NT) cells predominantly exist in human intestinal epithelium and may play an important role in local immunity.

Antigens, Surface↗
PubMed2002

Anabolic effects of recombinant human parathyroid hormone (1 - 84) and synthetic human parathyroid hormone (1 - 34) on the mandibles of osteopenic ovariectomized rats with maxillary molar extraction.

In rodent osteoporosis models such as ovariectomized (OVX) rats, intermittently administered human parathyroid hormone (hPTH) has an anabolic effect in vertebrae and long bones. In the present experiments, subcutaneously injected hPTH(1 - 34) or hPTH(1 - 84) dose- and time-dependently increased bone mineral density (BMD) as measured by dual energy X-ray absorptiometry in mandibles, L2 to L4 vertebrae and femurs of such rats. The highest dose (15.9 nmol/kg, s. c.) of either peptide given four times weekly for 10 weeks completely reversed the effects of overiectomy on BMD. Significant elevation in lumbar BMD after 10 weeks was observed with hPTH(1 - 34) or hPTH(1 - 84) at 1.1 nmol/kg, whereas hPTH(1 - 34) at 1.1 and 4.2 nmol/kg significantly increased BMD of the whole bone and the metaphysis of the femur and the diaphysis of the bone, respectively. In contrast, significant effects of hPTH(1 - 84) administration on BMD increase in the femur were observed at 4.2 and 15.9 nmol/kg in the whole bone and the metaphysis, and in the diaphysis, respectively. Maxillary molar extraction left mandibular BMD in rats with intact ovaries unchanged, but significantly decreased mandibular BMD in OVX rats. Administration of hPTH(1 - 84) for 10 weeks in OVX rats without or with extraction significantly increased BMD in the mandibular molar region at doses of 15.9 and 4.2 nmol/kg, respectively, indicating that efficacy was increased by extraction. A significant BMD increase in the molar region in OVX rats with extraction occurred at only 1.1 nmol/kg of hPTH(1 - 34) and 4.2 nmol/kg of hPTH(1 - 84). Also, BMD of the ramus region was increased by administration of both peptides to a lesser extent than that of the molar region in these rats. Thus, intermittent administration of hPTH, especially hPTH(1 - 34), has an anabolic effect on bone, particularly alveolar bone. Such treatment may increase alveolar bone mass in postmenopausal women with osteoporosis.

Absorptiometry, Photon↗
PubMed2002

[Surgical treatment of traumatic rupture of the bicuspid aortic valve; report of a case].

A 27-year-old man was injured during a motocross game. He was suffered from dyspnea, orthopnea, and hemoptysis. The to-and-fro murmur was noticed 3 days after the accident and then the patient was admitted to our hospital. Echocardiography revealed severe aortic regurgitation. Computerized tomography also showed severe pulmonary contusions. Seventeen days after the accident the aortic valve replacement was performed. The aortic valve was anterior-posterior type bicuspid valve (fusion of right coronary cusp and light coronary cusp) and the tear was detected in the anterior cusp. The postoperative course was uneventful. Rupture of the aortic valve due to a blunt chest trauma is rare and reported in 20 cases previously in Japan. This case is the second report of traumatic rupture of the bicuspid aortic valve.

Adult↗
PubMed2001

Analysis of the complete genome of indigenous swine hepatitis E virus isolated in Japan.

Using reverse transcription-polymerase chain reaction with primers derived from well-conserved genomic areas among all four hepatitis E virus (HEV) genotypes (I-IV), the HEV sequence was identified in serum samples obtained from 3 (3%) out of 95 60- to 90-day-old pigs in Japan and characterized molecularly. In the partial sequence of open reading frame (ORF) 2 of 421 nucleotides, the three swine isolates (swJ570, swJ681, and swJ791) showed the highest similarity of 83-87% to genotype III HEV representing human and swine strains (US1, US2, and swUS1) in the United States. The full-length nucleotide sequence of swJ570 consisted of 7225 nucleotides excluding the poly(A) tail and contained ORF 1 encoding 1703 amino acids (aa), ORF2 encoding 660 aa, and ORF3 encoding 122 aa. The swJ570 strain was most closely related to a Japanese strain (JRA1), which had been obtained from a hepatitis patient who had not traveled outside Japan. The overall nucleotide sequence identity between them was 89% and the deduced amino acid sequence identities of ORF1, ORF2, and ORF3 were 96, 99, and 98%, respectively. These results indicate that a certain proportion of pigs in Japan are HEV-viremic and may act as reservoirs of HEV infection, and that the presence of an indigenous strain(s) of HEV should be taken into consideration for the diagnosis of acute hepatitis in Japan.

3' Untranslated Regions↗