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Biomedical subjects

H Kurihara

Publications and source records attributed to H Kurihara.

At least 181 records · Page 10Linked to original sources

Clinicohistological study of oligodendroglioma and oligoastrocytoma.

The clinical and histological characteristics of oligodendroglioma and oligoastrocytoma were investigated in patients, mainly adults with supratentorial tumors, who were treated with surgery and radiotherapy, and with chemotherapy for recurrent, anaplastic tumors, or both. The median survival time was 13.2 years for oligodendroglioma (four patients), 12.7 years for anaplastic oligodendroglioma (five patients), 13.5 years for oligoastrocytoma (seven patients), and 4.8 years for anaplastic oligoastrocytoma (four patients). Two of three recurrent oligodendrogliomas and two of two recurrent oligoastrocytomas showed malignant transformation. Minigemistocytes were sometimes recognized in recurrent tumors and had a sinister prognosis. Oligodendroglioma and oligoastrocytoma may transform into each other at recurrence.

Adolescent↗

Physiological role of brain endothelin in the central autonomic control: from neuron to knockout mouse.

Although endothelin (ET) was discovered as a potent vascular endothelium-derived constricting peptide, its presumed physiological and pathophysiological roles are now considered much more diverse than originally though. Endothelin in the brain is thought to be deeply involved in the central autonomic control and consequent cardiorespiratory homeostasis, possibly as a neuromodulator or a hormone that functions locally in an autocrine/paracrine manner or widely through delivery by the cerebrospinal fluid (CSF). This notion is based on the following lines of evidence. (1) Mature ET, its precursors, converting enzymes, and receptors all are detected at strategic sites in the central nervous system (CNS), especially those controlling the autonomic functions. (2) The ET is present in the CSF at concentrations higher than in the plasma. (3) There is a topographical correspondence of ET and its receptors in the CNS. (4) The ET is released by primary cultures of hypothalamic neurons. (5) When ET binds to its receptors, intracellular calcium channels. (6) An intracerebroventricular or topical application of ET to CNS sites elicits a pattern of cardiorespiratory changes accompanied by responses of vasomotor and respiratory neurons. (7) Recently generated knockout mice with disrupted genes encoding ET-1 exhibited, along with malformations in a subset of the tissues of neural crest cell lineage, cardiorespiratory abnormalities including elevation of arterial pressure, sympathetic overactivity, and impairment of the respiratory reflex. Definitive evidence is expected from thorough analyses of knockout mice by applying conventional experimental methods.

Amino Acid Sequence↗

Simple in-office closure of small intractable tympanic membrane perforations after myringoplasty.

Perforations produced following myringoplasty are very difficult to close by ordinary cautery or patching even if they are small. Therefore we decided to close these intractable perforations with a skin graft from the cartilaginous ear canal. Our method is an in-office operation under local anesthesia. After the removal of epithelium from around the perforation a skin graft was placed by the over-lay method. A total of 11 patients were treated, of which 81.8% (9/11) demonstrated successful closure in the initial surgery and two re-perforations were successfully closed by a second and third operation, respectively. The technique used in this surgery is relatively easy and appropriate for in-office operations. The method's advantages include decreased invasiveness with minimal anesthesia and no requirement for ear canal packing or fixatives, and cosmetic benefit. This method also can be applied to perforations caused by chronic otitis media, traumatic perforations, and perforations after inserting tubes.

Adolescent↗

Persistent multiple climbing fiber innervation of cerebellar Purkinje cells in mice lacking mGluR1.

Most of the cerebellar Purkinje cells (PCs) of an adult animal are innervated individually by a single climbing fiber (CF) that forms strong excitatory synapses with the PCs. This one-to-one relationship between a PC and a CF is a consequence of a developmentally regulated regression of the innervation of PCs by CFs. We found that, in mice deficient in the type 1 metabotropic glutamate receptor (mGluR1), the regression of supernumerary CFs ceases by the end of the second postnatal week, which is about one week earlier than in normal mice. Consequently, about one third of PCs in the mGluR1 mutant mice are innervated by multiple CFs in adulthood. We conclude that the regression of CFs normally occurs in two developmental phases and that mGluR1 plays a crucial role in the second phase.

Aging↗

Calmodulin purified from human and porcine thyroids inhibits thyrotropin binding to porcine thyroid cells.

A thyrotropin (TSH) binding inhibiting protein (TBIP) that inhibits TSH binding to the TSH receptor, as determined by the TSH receptor assay, was purified from human and porcine thyroid. The soluble fraction (100,000 x g supernatant of Graves' thyroid homogenate) was precipitated with ammonium sulfate between 1.75 to 2.5 mol/L. TBIP was eluted by 0.5 mol/L sodium chloride (NaCl) containing 20 mmol/L Tris buffer, pH 7.5 from a Q-sepharose column. The unbound fraction from concanavalin A (Con A) and blue-sepharose was gel-filtered using sephadex G-100, and finally purified by Resource Q column chromatography. Purified TBIP was confirmed as a single protein band of 17 kDa. The TBI activity in the purified TBIP was significantly decreased by either etnylene glycol tetraacetate (EGTA) (1 mmol/L) or antibody to calmodulin (CaM) in the TSH receptor assay. The TBIP was confirmed immunologically as CaM by the Ouchterlony method using antibody for CaM. These findings demonstrated that the TBIP purified from human and porcine thyroids was, in fact, CaM. We examined the effects of TBIP purified from human thyroid on bovine TSH (bTSH) or thyroid stimulating antibody (TSAb)-stimulated cyclic adenosine monophosphate (cAMP) production in porcine thyroid cells (PTC). TBIP itself did not increase basal levels of cAMP production, but inhibited bTSH (100 mU/L)-stimulated cAMP production. However, TBIP did not inhibit cAMP production stimulated by TSAb-IgG and various thyroid stimulators (GTPgammaS, forskolin and pituitary adenylate cyclase-activating polypeptide [PACAP, 27 and 38 amino acids]). Authentic CaM purified from bovine brain behaved in a manner similar to that of TBIP. These data showed that CaM differentially affects thyroid stimulation by TSH and TSAb in intact thyroid cell experiments.

Animals↗

Effective cross-circulation technique of venoarterial bypass for differential hypoxia condition.

We examined a new technique of cross-circulation (CC) venoarterial bypass (VAB) with femoral arterial perfusion and superior vena cava drainage through a long femoral venous cannula. Six adult mongrel dogs weighing 15 to 20 kg underwent the CC-VAB with oxygenation after introduction of respiratory failure (RF). The flow of the CC-VAB was maintained at half the level of the control cardiac output, and the hemodynamic parameters were monitored. To evaluate hypoxia in the upper body, the arterial partial pressure of oxygen (PaO2 [mm Hg]) in the carotid artery and the venous saturation of oxygen (SvO2 [%]) in the pulmonary artery were measured during control, RF, standard VAB, and CC-VAB conditions. The PaO2 decreased significantly after the introduction of RF (41.7 +/- 12.4), and it returned to normal levels only after CC-VAB (151.2 +/- 24.5, p < 0.05). The SvO2 during CC-VAB (98.6 +/- 2.1) was significantly higher than that during VAB without CC (53.5 +/- 3.4, p < 0.05). These results suggest that this cross-circulation technique could be applied to patients with differential hypoxia during femoral VAB with oxygenation or percutaneous cardiopulmonary support (PCPS).

Analysis of Variance↗

Significant left ventricular unloading with transaortic catheter venting during venoarterial bypass.

Insufficient unloading of the left ventricle with blood stagnation is a main cause of unsuccessful left ventricular (LV) recovery during percutaneous cardiopulmonary support (PCPS). The purpose of this investigation was to evaluate the effectiveness of transaortic catheter venting (TACV) for LV unloading. Six adult mongrel dogs (mean weight 16.3 kg, range 14-20 kg) underwent venoarterial bypass (VAB) with TACV. Bypass flow ranged from 0.8-1.2 L/min, and TACV flow ranged from 160-240 ml/min. In addition to monitoring the standard hemodynamic parameters, the slope of the LV end-systolic pressure-volume relation (Emax) during transient occlusion of the inferior vena cava, the slope of the LV end-systolic pressure-stroke-volume relation (Ea), the stroke work (SW), the LV pressure-volume area (PVA), and the slope of the SW end-diastolic volume relation, the preload recruitable stroke work (PRSW) were assessed by means of a microtip manometer and a conductance catheter. The LV contractility (Emax) and aortic elastance (Ea) were equivalent in the 2 groups with or without TACV (7.7 +/- 1.1 versus 8.4 +/- 1.5 mm Hg/ml and 8.2 +/- 1.4 versus 7.6 +/- 1.3 mm Hg/ml). Comparing the measurements for the baseline to those for VAB with TACV, the SW was significantly reduced, and the PVA/SW was increased by TACV (1,685 +/- 309 versus 867 +/- 188 x 10(-4) J, p < 0.05 and 1.32 +/- 0.03 versus 1.58 +/- 0.11, p < 0.05, respectively). Furthermore, the PRSW was gradually decreased from the baseline value to the value resulting from VAB with TACV (75 +/- 8 versus 44 +/- 3 x 10(-4) J/ml, p < 0.01). In comparison, the percent reduction of SW between VAB and VAB with TACV tended to be increased by TACV (23.2 +/- 7.2% versus 46.9 +/- 7.7%, p = 0.05). These results suggest that TACV might reduce LV work (SW and PRSW) and might increase the LV energetic charge. In conclusion, TACV would be an adjunctive technique to VAB or PCPS for patients with LV failure.

Angioplasty, Balloon, Coronary↗

Assessment of in vitro interleukin-2-producing capacity of peripheral blood lymphocytes from patients with periodontitis.

In this cross-sectional study, we assessed the in vitro interleukin-2 (IL-2) producing capacity of peripheral blood mononuclear cells (PBMC) and lymphocytes from patients with different forms of periodontitis. 45 patients (12 with localised early onset periodontitis (LEOP), 20 with generalised early onset periodontitis (GEOP), and 13 with adult periodontitis (AP), and 20 periodontally healthy subjects (HS), participated in this study. PBMC and lymphocytes were isolated from the subjects and their cells were stimulated with an anti-CD3 monoclonal antibody (anti-CD3 MoAb) and the secreted IL-2 levels in the culture were bioassayed. No significant differences could be found in IL-2 producing activity of PBMC between the patients and HS group. There was wide interindividual variation and high and low "IL-2 producers" were noted. We found a LEOP patient who was a high producer of IL-2 (> mean + 8 SD) and 2 LEOP patients and a HS who were low producers of IL-2 (< mean - 1.5 SD) with their lymphocytes. Incidentally, the HS became a LEOP patient during 2 years after this study. The low IL-2 producing activity of their PBMC and lymphocytes against anti-CD3 MoAb could not be overcome by stimulation with phorbol myristate acetate and ionomycin. Thus, we found high and low IL-2 producing capacity by PBMC and lymphocytes in certain subjects and these subjects may be useful models in assessing the role of systemic IL-2 productivity associated with their progression of periodontal disease.

Adolescent↗

Fecal microflora in a patient with short-bowel syndrome and identification of dominant lactobacilli.

Fecal microflora and lactate concentrations in blood and feces obtained from a patient (a 5 year-old boy) with short-bowel syndrome (SBS) were compared during acidosis to results for the normal condition (no SBS symptoms). The taxonomical position of the lactobacilli found predominantly in the feces sample obtained 2 days before the fifth attack was also studied. The D-lactate level in serum obtained 1 day after the fourth attack was 10-fold higher than that for the normal condition, although there was not a great difference in L-lactate levels. D-Lactate (3.91 mM) and L-lactate (2.86 mM) were also detected in the feces samples collected 2 days before the fifth attack, while no lactate was detected in the feces sample for the normal condition. The counts of total fecal bacteria, especially anaerobic bacteria such as members of the family Bacteroidaceae, were found to be low. The counts of lactobacilli and the total population of lactobacilli relative to total fecal bacteria in the feces 2 days before the fifth attack (40.4%) were extremely high. In this case, a majority of the lactobacilli were D-lactate producers as determined by homolactic fermentation. These lactobacilli were identified as Lactobacillus delbrueckii subsp. lactis. The percentages of bifidobacteria relative to total fecal bacteria in feces samples obtained both 2 days before the fifth attack (50.9%) and for normal condition (61.9%) were also high, although these bacteria were L-lactate producers. In the feces samples for the normal condition, the D-lactate producers decreased to less than 10(9) per g, while the counts of L- or DL-lactate producers were 100-fold higher than the numbers in feces samples obtained 2 days before the fifth attack. These results suggested that an increase in the level of D-lactate producers, such as L. delbrueckii subsp. lactis, in the colon may be associated with the clinical expression of metabolic acidosis.

Acidosis, Lactic↗

Characterization of Bacteroides forsythus isolates.

Fifteen Bacteroides forsythus strains freshly isolated from patients with periodontitis were used together with three collection strains and one type strain for characterization of growth on various media; determination of enzymatic profiles, antibiotic susceptibility profiles, 16S rRNA ribotypes, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) outer membrane protein profiles, and pathogenicity; and gas chromatography analysis by using a wound chamber model in rabbits. All strains were stimulated by N-acetylmuramic acid, while one strain needed a further supplement such as yeast extract for optimal growth. All strains showed trypsin-like activity. While 10 different ribotypes were found, the SDS-PAGE profiles revealed similar patterns for all strains. All strains were sensitive to penicillin G (MICs, <0.5 microg/ml), ampicillin (MICs, <1.0 microg/ml), amoxicillin (MICs, <0.38 microg/ml), metronidazole (MICs, <0.005 microg/ml), tetracycline (MICs, <0.19 microg/ml), doxycycline (MICs, 0.05 microg/ml), erythromycin (MICs, <0.4 microg/ml), and clindamycin (MICs, <0.016 microg/ml), while they were less sensitive to ciprofloxacin (MICs, <4 microg/ml). B. forsythus did not cause abscess formation by monoinoculation. B. forsythus coinoculated with Fusobacterium nucleatum ATCC 10953 caused abscess formation in 75% of rabbits, while it caused abscess formation in 100% of rabbits when it was coinoculated with Porphyromonas gingivalis FDC 381. In the case of the latter combination, four of six rabbits died of sepsis after 6 to 7 days, and P. gingivalis and B. forsythus were recovered from the heart blood at a proportion of 10:1. B. forsythus strains were highly virulent and invasive in combination with P. gingivalis.

Abscess↗

Slit diaphragm-reactive nephritogenic MAb 5-1-6 alters expression of ZO-1 in rat podocytes.

Monoclonal antibody (MAb) 5-1-6 identifies a 51-kDa protein (p51) on rat podocyte foot processes and causes severe complement- and leukocyte-independent proteinuria when injected into rats. In the studies reported here, we used various immunohistological techniques to define the precise location of p51 and its relationship to ZO-1, a known component of the podocyte slit diaphragm in adult rat glomeruli. Our results demonstrate that p51 and ZO-1 lie close to each other on opposite sides of the podocyte plasma membrane at the point of insertion of the slit diaphragm: ZO-1 on the cytoplasmic face and p51 on the slit diaphragm and adjoining outer leaflet of the plasma membrane bordering the filtration slits. In addition to their geographic proximity, there appears to be a relationship between p51 and ZO-1. After MAb 5-1-6 injection, there was a progressive decline in stainable ZO-1 in the podocytes of heavily proteinuric rats. In addition, Western blot analysis of glomerular lysates showed that the decline in staining was due to a loss of immunoreactive ZO-1 rather than redistribution or diffusion of the protein. Simultaneously, the distribution of glomerular-bound MAb 5-1-6 became more clumped, apparently because of partial endocytosis into a lysosomal compartment, while the slit diaphragms remained morphologically intact. These findings suggest that MAb 5-1-6 alters the molecular composition of the slit diaphragm and thereby affects the glomerular permeability barrier.

Animals↗

Dual effects of lisinopril on puromycin aminonucleoside nephrosis in unilaterally nephrectomized rats.

The therapeutic effects of angiotensin converting enzyme inhibitor, lisinopril, on puromycin aminonucleoside (PAN)-induced nephrosis were investigated using unilaterally nephrectomized rats. Lisinopril showed potent dual effects on PAN nephrosis. Lisinopril treatment (50 mg/l in drinking water) from day 5 or day 9 reduced urinary protein excretion and suppressed the development of glomerular sclerosis at 8 weeks after PAN injection (150 mg/kg, i.p.), indicating a therapeutic effect on the nephrosis. Recovery of decreased anionic charge sites on the glomerular basement membrane was involved, at least in part, in the therapeutic action of lisinopril against proteinuria. On the other hand, oliguria and progressive azotemia derived from continuous deterioration of the renal function was induced if the treatment of lisinopril was started on the same day as PAN injection. The renal dysfunction induced by simultaneous administration of lisinopril with PAN could be abolished by combination dosing with sarcosine, an angiotensin II (AII)-receptor agonist. These results indicate that lisinopril treatment attenuates proteinuria by ameliorating the anionic charge barrier on the glomerular basement membrane and that it also protects against the development of chronic renal disease with segmental glomerular sclerosis, although AII depletion during the acute nephrotic stage exacerbates the renal damage in PAN nephrosis of unilaterally nephrectomized rats.

Angiotensin-Converting Enzyme Inhibitors↗

Isolation and identification of alpha-glucosidase inhibitors from tochu-cha (Eucommia ulmoides).

alpha-Glucosidase inhibitory activity was found in aqueous methanol extracts of tochu-cha, dried leaves of Eucommia ulmoides (Eucommiaceae). Five active principles against yeast enzyme were isolated and characterized. Among them, quercetin (1, Ki: 8.5 x 10(-6) M) was considered to contribute mostly to the activity of the tochu leaves. In regard to an animal alpha-glucosidase, rat intestinal sucrase activity was also inhibited by 1.

Animals↗

Germ-line contribution of embryonic stem cells in chimeric mice: influence of karyotype and in vitro differentiation ability.

The effect of the karyotype and the ability to differentiate in vitro upon germ-line transmission by A3-1 embryonic stem (ES) cells in chimeric mice were examined. Germ-line transmission was confirmed in ES cells exhibiting 38% and more of the normal karyotype, but no chimeric mice and/or germ-line transmitters were observed regardless of the karyotype when the cystic embryoid body (CEB) was formed on day 8 and later in the suspension culture. Germ-line transmission of the ES cells was not significantly influenced by formation of the simple embryoid body (SEB). Germ-line transmitters were preferentially observed in chimeras when the ES cell contribution to coat color was markedly increased, but this contribution to coat color varied regardless of the karyotype or in vitro differentiation ability. These results suggest that A3-1 ES cells which exhibit CEB at 7 days after suspension culture and approximately 40% of normal karyotype are capable of germ-line transmission in chimeric mice.

Animals↗

Host defensive, immunological, and microbiological observations of an early-onset periodontitis patient with virus-associated hemophagocytic syndrome.

Virus-associated hemophagocytic syndrome (VAHS) is a disorder characterized by benign generalized histiocytic proliferation and marked hemophagocytosis associated with systemic viral infection. An immunodeficiency which includes an extremely decreased leukocyte and platelet count together with abnormalities in the CD4/CD8 ratio are the most common features of VAHS. Here we report an early-onset periodontitis (EOP) patient with VAHS from the standpoint of host-parasite interaction to understand the effect of this systemic disorder which might possibly influence susceptibility to periodontal disease. The patient is a 16-year-old Japanese male clinically diagnosed as having generalized EOP with slight gingival inflammation and moderate bone loss. This patient manifested VAHS at 3 years of age, and then had an unusual 4 recurrences (at 5, 7, 11, and 14 years old). Laboratory tests conducted include: 1) complete blood analyses: 2) peripheral neutrophil functions (chemotaxis, phagocytosis, superoxide production, and adherence); 3) peripheral lymphocyte subpopulations and functions, T-cell proliferative activity and productivity of cytokines (interleukin-2 [IL-2], interferon gamma [IFN-gamma], and tumor necrosis factor alpha [TNF-alpha]); 4) serum cytokine levels (IL-1 beta, IL-2, soluble IL-2 receptor [sIL-2R], IL-4, IL-6, IFN-gamma, and TNF-alpha; 5) serum immunoglobulin G (IgG) antibody titers against periodontopathic bacteria; 6) serological human leukocyte antigen (HLA) typing; and 7) determination of bacterial flora of the periodontal pockets. The results indicated that the patient's neutrophil chemotaxis and random migration were below the normal range. In lymphocyte examinations, T-cell proliferative activity, IL-2, and IFN-gamma productivity were elevated. Serum IFN-gamma level was also significantly higher than normal range. No specific periodontopathic bacteria were predominant in the periodontal pockets, however, the serum IgG titer against Porphyromonas gingivalis was elevated throughout the examination period. It is suggested that VAHS might be a possible risk factor for periodontal disease, and hence may serve as a model in understanding the role of host defense mechanisms in the establishment of inflammatory periodontal disease.

Adolescent↗

Digoxigenin-labeled deoxyribonucleic acid probes for the enumeration of bifidobacteria in fecal samples.

The numbers of bifidobacteria in fecal samples were specifically determined by colony hybridization with the mixture of digoxigenin-labeled DNA probes that were prepared from whole chromosomal DNA of Bifidobacterium longum 6001 and Bifidobacterium adolescentis 6003. These DNA probes strongly hybridized with DNA of B. longum, B. adolescentis, Bifidobacterium breve, Bifidobacterium suis, Bifidobacterium infantis, Bifidobacterium bifidum, Bifidobacterium angulatum, and Bifidobacterium animalis. Detectable positive signals with DNA of Bifidobacterium pseudolongum ssp. pseudolongum, Bifidobacterium catenulatum, and Bifidobacterium thermophilum were also found after hybridization. When dot-blot hybridization was performed with whole cells of 47 reference strains containing 11 species (16 strains) of bifidobacteria, all of the bifidobacteria tested could be specifically detected by using these DNA probes; Lactobacillus fermentum JCM 1173, however, showed a slight nonspecific signal. The counts of bifidobacteria by colony hybridization in the fecal samples of four of the five subjects were the same as the counts that were obtained by the conventional method using BL agar medium. Furthermore, no significant difference existed in the number of bifidobacteria that were determined by either method.

Adult↗

The effect of iodine-based contrast agents on the levels of radiation-induced chromosomal aberrations.

The effects of iodine-based contrast agents on the repair of radiation-induced chromosomal damage were investigated employing peripheral blood from a healthy male donor. The blood samples were irradiated with 0.5-4.0 Gy 137Cs gamma rays. Contrast agents and NaCl solutions of various concentrations were added to the blood within the first 15 min or at 60 min after irradiation, and the samples were subsequently cultured for 45 h at 37 degrees C. Significantly elevated frequencies of chromosomal abnormalities caused by postirradiation treatment with hypertonic contrast agents appeared to increase with increasing hypertonicity. Elevated aberration frequencies were found to be greatest in the samples treated within 15 min of irradiation. The contrast agents had little effect if they were added at 60 min after irradiation, probably because the process of chromosome rejoining had been completed. Isotonic iodine-based contrast agents did not enhance the frequencies of chromosomal aberrations to a significant degree.

Adult↗

[Gene Polymorphism of 5, 10-methylenetetrahydrofolate reductase as a coronary risk factor].

Hyperhomocysteinemia has been identified as a possible risk factor for coronary artery disease. The association of the alanine/valine (A/V) polymorphism of 5, 10-methylenetetrahydrofolate reductase (MTHFR), one of the key enzymes catalyzing re-methylation of homocysteine, with coronary artery disease was examined in 362 Japanese males with a diagnosis of coronary artery disease confirmed with coronary angiography. The A/V polymorphism was analyzed with PCR followed by Hinf I digestion. The screening of 778 male volunteer controls revealed that the frequency of V allele in Japanese was 0.33, comparable to that in the French Canadian population. The VV genotype, which correlates with increased plasma homocysteine levels due to reduced activity and increased thermolability of this enzyme, was significantly more frequent in patients with coronary artery disease (15.7%, n = 362) than in controls (10.2%, n = 778; p = 0.0067). The association of the VV genotype with coronary artery disease was further increased in patients with > or = 99% stenotic lesion (p = 0.0010). In these patients, the frequency of the VV genotype was significantly higher in patients with triple-vessel disease (26%) than in patients with single- or double-vessel disease (15% and 14%, respectively). The fasting plasma homocysteine levels in VV subjects were higher than those in AV or AA subjects. The VV genotype of MTHFR associated with increased plasma homocysteine levels may represent an important genetic risk factor for coronary artery disease, especially with the occurrence of myocardial infarction.

Adult↗