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Biomedical subjects

Y Ishida

Publications and source records attributed to Y Ishida.

At least 289 records · Page 16Linked to original sources
PubMed1996

Reduction of 123I-iomazenil uptake in haemodynamically and metabolically impaired brain areas in patients with cerebrovascular disease.

Iomazenil is a specific ligand for central-type benzodiazepine receptors (BZR). In order to determine the clinical significance of the findings of 123I-iomazenil single photon emission tomography (SPET) in cerebrovascular disease (CVD), we compared the cerebral uptake of 123I-iomazenil with oxygen metabolism measured by positron emission tomography (PET). Depending on the severity of the haemodynamic and/or metabolic impairment based on our institutional criteria [a reduction of < 30.6 ml 100g-1 min-1 in cerebral blood flow (CBF) and an increase of > 0.52 in the oxygen extraction fraction (OEF)], the cortical areas were classified into four groups as follows: Group I, normal CBF and OEF; Group II, normal CBF and increased OEF; Group III, reduced CBF and normal OEF; Group IV, reduced CBF and increased OEF. Seven patients (mean age 65 +/- 7 years) with CVD underwent both PET and 123I-iomazenil SPET within 8 days. The ratios of the mean counts in 14 regions of interest in the cerebral cortices to those in the cerebellar cortices (R/C ratios) were compared with the cerebral metabolic rate of oxygen (CMRO2). The R/C ratios of Group IV were lower than those of Group I (P < 0.005). The R/C ratios correlated with CMRO2 in Group III (r = 0.577, P < 0.01) and in Group IV (r = 0.707, P < 0.005), but not in Groups I or II. These results suggests that reduced uptake in 123I-iomazenil SPET reflects oxidative hypometabolism causing neuronal damage in haemodynamically and metabolically impaired areas in patients with CVD. This information may be valuable when deciding therapeutic approaches.

Aged↗
PubMed1996

Vasoreactive effect of acetazolamide as a function of time with sequential PET 15O-water measurement.

The accurate assessment of vascular flow reserve is crucial for the evaluation of risk among patients with cerebrovascular disease. In six patients with unilateral occlusion of the internal carotid artery and one patient with unilateral occlusion of the middle cerebral artery (mean +/- S.D. age = 68 +/- 3 years), we measured cerebral blood flow (CBF) after the administration of 940 MBq 15O-water using a remotely controlled power injector. Studies were performed at rest, after 10 min, and then 10, 20 and 30 min after the administration of 1 mg acetazolamide to evaluate the vasoreactive effect, as reflected by an increase in CBF. Sixteen regions of interest (ROIs) were drawn over the CBF images. These ROIs were as follows in each hemisphere: Area I, four areas in the cortical middle cerebral arterial territory (superior frontal, frontal, temporal and parietal areas); Area II, four areas of the deep middle cerebral and vertebral arterial territory (occipital area, basal ganglia, thalamus and cerebellum). Taking normalized resting CBF to be 100%, the mean CBF measured 10, 20 and 30 min post-injection using sequential positron emission tomography was as follows: Area I, 141.4 +/- 16.3, 127.7 +/- 15.3 and 128.2 +/- 17.4% for non-occluded sites and 116.3 +/- 22.8, 112.7 +/- 16.4 and 114.9 +/- 17.1% for occluded sites; Area II, 143.4 +/- 14.5, 126.2 +/- 10.4 and 125.0 +/- 12.9% for non-occluded sites and 141.9 +/- 28.9, 126.0 +/- 20.5 and 124.1 +/- 17.1% for occluded sites. A significant difference in mean CBF was noted between the non-occluded and occluded sites in Area I, the most marked difference of 25.1% being observed 10 min after the administration of the acetazolamide. We conclude that for an accurate assessment of vascular reserve in patients with cerebrovascular disease, CBF should be measured 10 min post-administration of the acetazolamide.

Acetazolamide↗
PubMed1996

Aeropyrum pernix gen. nov., sp. nov., a novel aerobic hyperthermophilic archaeon growing at temperatures up to 100 degrees C.

A novel aerobic hyperthermophilic archaeon was isolated from a coastal solfataric vent at Kodakara-Jima Island, Japan. The new isolate, strain K1, is the first strictly aerobic organism growing at temperatures up to 100 degrees C. It grows optimally at 90 to 95 degrees C, pH 7.0, and a salinity of 3.5%. The cells are spherical shaped and 0.8 to 1.2 microns in diameter. Various proteinaceous complex compounds served as substrates during aerobic growth. Thiosulfate stimulates growth without producing H2S. The core lipids consist solely of C25-isopranyl archaeol (glycerol diether). The G + C content of the genomic DNA is 67 mol%. Phylogenetic analysis based on 16S rRNA sequence indicates that strain K1 is a new member of Crenarchaeota. On the basis of our results, the name Aeropyrum pernix gen. nov., sp. nov. is proposed (type strain: K1; JCM 9820).

Archaea↗
PubMed1996

Rhodothermus obamensis sp. nov., a modern lineage of extremely thermophilic marine bacteria.

A novel extremely thermophilic bacterium was isolated from a shallow marine hydrothermal vent environment (depth, 22 m) in Tachibana Bay, Nagasaki Prefecture, Japan. The cells of this organism were gram-negative rods. Growth occurred at temperatures between 50 and 85 degrees C (optimum temperature, 80 degrees C; doubling time at optimum temperature, 90 min), at pH 5.5 and 9.0 (optimum pH, 7.0), and in the presence of 1 and 5% NaCl (optimum NaCl concentration, 3%). The new isolate was an aerobic heterotroph which utilized the following compounds as sole energy and carbon sources: yeast extract, peptone, starch, casein, Casamino Acids, a variety of sugars, some carboxylic acids, and amino acids. As determined by a sequence analysis of the 16S rRNA, the new isolate belongs to the genus Rhodothermus and represents a modern lineage of extreme thermophiles within the domain Bacteria. On the basis of the physiological and molecular properties of the new isolate, we describe a new species, Rhodothermus obamensis. The type strain of R. obamensis is strain OKD7 (= JCM 9785).

Base Sequence↗
PubMed1996

Change of immunological parameters in the clinical course of a myasthenia gravis patient with chronic graft-versus-host disease.

The change in immunological parameters was studied during the clinical course of a myasthenia gravis (MG) patient with chronic graft-versus-host disease (GVHD), which developed after bone marrow transplantation from an HLA-identical donor. Anti-acetylcholine receptor antibody gradually decreased in the patient treated with immunosuppressive agents, but was not detected in the donor. Lymphocyte numbers were low just before the onset of MG, increased abruptly within several days and then gradually decreased with treatment. The percentage of CD3+ and CD19+ lymphocytes was higher at onset than before, the percentage of CD4+ cells was higher at onset and gradually decreased with treatment, while CD8+ cells showed the lowest level just before onset and gradually increased during the clinical course. CD4+/CD45RA- cells also showed the highest levels at onset and a gradual decrease with treatment. Cellular, as well as humoral immune responses, might be associated with the pathogenesis of MG with chronic GVHD.

Child↗
PubMed1996

Diurnal heart rate variability in healthy subjects: effects of aging and sex difference.

To study the effects of aging and gender, circadian profiles of heart rate variability were evaluated for 105 healthy volunteers by frequency domain analysis of a Holter electrocardiogram record. The low-frequency (LF) component representing cardiac beta-adrenergic function showed high values for the 0800-1200 period in male subjects and the 1200-2400 period in female subjects. The high-frequency (HF) component representing parasympathetic function showed a peak for the 0000-0600 period in both male and female subjects independent of age. Male subjects showed significantly higher %LF [LF/(LF + HF) x 100] than female subjects. LF showed consistently highly significant correlation with age. These basic findings can help elucidate the diurnal profile of cardiac nerve function and how it is affected by aging and sex difference.

Adult↗
PubMed1996

Lactate production of mammalian intestinal and vascular smooth muscles under aerobic and hypoxic conditions.

Lactate liberation from thoracic aortas and intestinal smooth muscles of the guinea pig, rabbit and rat, as well as coronary arteries of the dog were determined'under aerobic and hypoxic conditions (95% N2 instead of O2). In all smooth muscles tested, the lactate liberation was inhibited in the presence of oxygen, being known as the Pasteur effect. The rates of lactate release from guinea pig aortas and taenia caeci under hypoxia were approximately 10 times greater than those under aerobic conditions. The rate of lactate release from other smooth muscles tested were 3-4 times greater under hypoxic than aerobic conditions. The extent of Pasteur effect was not affected by a removal of adventitial layer from the rabbit aorta nor by the different size of the dog coronary arteries. These results suggest that taenia caeci and aortas of the guinea pig intrinsically possess a strong regulatory system in the glycolytic activity, being highly sensitive to the presence of oxygen.

Aerobiosis↗
PubMed1996

VLDL triglyceride kinetics in Wistar fatty rats, an animal model of NIDDM: effects of dietary fructose alone or in combination with pioglitazone.

The effects of dietary fructose alone or in combination with a new oral agent, pioglitazone, on VLDL-triglyceride (TG) turnover were studied in genetically obese Wistar fatty rats characterized by hyperinsulinemia (7,488 +/- 954 pmol/l), hyperglycemia, (22.5 +/- 1.4 mmol/l), and hypertriglyceridemia (4.39 +/- 0.54 mmol/l). They had an increased hepatic TG production (16.2 +/- 0.1 micromol/min; lean rats, 5.4 +/- 0.3 micromol/min) as well as a longer half-life of VLDL-TG from lean donors (8.8 +/- 1.4 min, lean recipients; 2.3 +/- 0.9 min). In addition, in lean recipients, the half-life of VLDL-TG from fatty donors was longer than that from lean donors (4.80 +/- 0.56 vs. 3.14 +/- 0.23 min). Although feeding fructose into fatty rats did not change plasma glucose and insulin levels, it produced a twofold increase in TG levels (8.74 +/- 1.15 mmol/l). This was associated with a 1.7-fold increase in TG production to 27.5 +/- 1.2 micromol/min, while no significant change was found in the half-life of lean VLDL-TG in fructose-fed fatty recipients (10.9 +/- 2.4 min) or in that of VLDL-TG from fructose-fed fatty donors in lean recipients (4.46 +/- 0.76 min). Daily administration of pioglitazone (3 mg/kg body weight) in fructose-fed fatty rats ameliorated glycemia and triglyceridemia to the level of lean rats (8.1 +/- 0.7 and 1.18 +/- 0.05 mmol/l, respectively) and insulinemia to a lesser extent (2,712 +/- 78 pmol/l). A fall in TG levels was associated with improvement of an impairment in the ability of fructose-fed fatty rats to remove lean VLDL-TG (half-fife: 2.6 +/- 0.6 min). Pioglitazone, however, produced no change in TG production (25.9 +/- 2.7 micromol/min), the half-life of VLDL-TG from fructose-fed fatty donors in lean recipients (4.17 +/- 0.38 min), or the activity of lipoprotein lipase and hepatic lipase in postheparin plasma. We conclude that in Wistar fatty rats 1) hypertriglyceridemia is attributed to TG overproduction and impaired TG catabolism, and the latter is due to changes in both VLDL, such that they are less able to be removed, and changes in the nature of Wistar fatty rats, such that they are less able to remove VLDL-TG; 2) fructose further increases hepatic TG production with a resultant deterioration in hypertriglyceridemia; 3) pioglitazone normalizes TG levels by altering the physiology of the Wistar fatty rats in a manner that increases their ability to remove VLDL-TG from the circulation.

Animals↗
PubMed1996

[Infection in elderly leukemic patients].

Febrile episodes occurring in 29 elderly patients (mean age 75 years) with leukemia, from 1988 to 1993, were reviewed. A febrile episode was defined as a temperature of 38 degrees C or greater for at least 6 hours. The number of febrile episodes was 64. The average was 2.2 febrile episodes per patient. Seventy-two percent of febrile episodes occurred when the patients had neutropenia below 100/microliters, while 16% occurred with neutropenia of 101/microliters to 500/microliters. Causative microorganisms were identified in 48% of total febrile episodes. The most common infectious site was the urinary tract which accounted for 25% of total episodes. Pneumonia and septicemia accounted for 22% of total episodes, respectively. Gram-positive cocci were responsible for 66% of microbiologically documented febrile episodes, while 21% were caused by gram-negative bacilli. Gram-positive cocci, particularly staphylococcus aureus, coagulae-negative staphylococcus and enterococci increased compared with a decade ago in our department. Granulocyte colony-stimulating factor (G-CSF) was used 12 times for infection. No significant difference in fever amelioration was seen between G-CSF and non-G-CFS cases.

Aged↗
PubMed1996

Long-term follow-up review of suspension laminotomy for cervical compression myelopathy.

This study compared the long-term outcome of cervical spondylotic myelopathy (CSM) with that of the ossification of the posterior longitudinal ligament of the cervical spine (OPLL) after suspension laminotomy, which was developed in the authors' clinic. Seventy-six patients who received follow-up care for more than 5 years were available for analysis. The duration of the follow-up period averaged 97.8 months (range 61-160 months). Radiological and neurological analyses were performed in these 76 patients (50 with CSM and 26 with OPLL). There were no differences in sex, age, follow-up period, and preoperative neurological status between the two groups. In the quantitative study of the dural configuration, 43 patients (86%) with CSM and 17 patients (65.4%) with OPLL attained complete decompression 1 month after surgery. At long-term follow-up review, complete decompression was maintained in 42 patients (84%) with CSM but in only seven patients (26.9%) with OPLL. The neurological evaluation improved markedly at early follow up in both groups but declined insignificantly at the last follow-up review, particularly in the OPLL group. Of 12 patients (24%) with CSM and 10 patients (38.5%) with OPLL whose neurological recovery grades later deteriorated, four (8%) with CSM and nine (34.6%) with OPLL demonstrated reconstriction causing spinal cord compression at long-term follow-up review. For the remaining eight patients (16%) with CSM, who were older than 70 years on average at last follow-up review, no radiological explanation was found. These long-term results indicate that OPLL does not resolve as well as CSM after suspension laminotomy; they both may have late deterioration due to reconstriction that occurs occasionally in CSM and frequently in OPLL.

Adult↗
PubMed1996

[A case of huge renal angiomyolipoma calculated doubling time].

A 32-year-old man was admitted with a sudden onset of severe left flank pain. The abdominal and MRI showed bilateral renal tumors with left perirenal hematoma. Selective right renal biopsy under the guidance of ultrasonography revealed that right renal tumor was angiomyolipoma (AML). After performing left renal embolization of the left renal artery, left was performed. The histology of the excised specimen was also AML. This patient had visited to the other clinics in 1985 and in 1988, and was examined by CT. Accordingly, doubling time of this tumor was calculated by ellipsoid method. Doubling time in 1985-1988 was days, and that in 1988-1995 was 675 days. Growth change of left renal AML did not show curve.

Adult↗
PubMed1996

Maladaptation of vascular response in frontal area of patients with orthostatic hypotension.

UNLABELLED: To clarify the relationship between abnormalities in cerebral blood flow (CBF) and in blood pressure regulation, we performed 99mTc-HMPAO brain SPECT in association with measurement of plasma norepinephrine and blood pressure in both the upright and supine positions. METHODS: We studied six patients with orthostatic hypotension and six normal patients. No patient had any significant stenosis of the carotid arteries on echocardiography-Doppler ultrasound and no abnormalities on brain MRI or CT. Changes in systolic blood pressure were monitored during the upright test, and 8-ml blood samples were taken at baseline and at 1 and 5 min after the upright position. RESULTS: Systolic blood pressure decreased by a mean of 38 +/- 10 and 9 +/- 3 mmHg in the orthostatic hypotension and normal groups, respectively. Compared with baseline values, plasma norepinephrine levels at 1 and 5 min after the upright test did not increase in the orthostatic hypotension group but did increase significantly in the normal group. In the orthostatic hypotension group, 99mTc-HMPAO brain SPECT showed postural cerebral hypoperfusion in the bilateral frontal areas, of which the mean count ratio of the frontal-to-cerebellar area between the upright and supine positions significantly changed from 0.871 +/- 0.029 to 0.942 +/- 0.067 and from 0.881 +/- 0.035 to 0.954 +/- 0.073 in the right and left areas, respectively. No postural change in CBF was evident in other areas in the orthostatic hypotension group. In the normal group, there were no such changes in CBF, blood pressure and plasma norepinephrine levels during the upright test. CONCLUSION: Postural cerebral hypoperfusion in the frontal areas in the orthostatic hypotension group might relate to maladaptation of the vascular response during the upright test.

Blood Pressure↗
PubMed1996

Determination of S-phase cells by in situ hybridization for histone H3 mRNA in hepatocellular carcinoma: correlation with histologic grade and other cell proliferative markers.

Cell proliferation has a crucial importance in biologic potentialities of tumor cells. Several methods to measure S-phase fraction in tumor samples have been developed, with considerable limitations in practical applications. Histones are nucleosomal proteins that are responsible for packaging chromosomal DNA into nucleosomes. The expression of histone genes is a fundamental step constituting the process of cell proliferation. Because histone H3 mRNA accumulates in the cytoplasm during S-phase, and then decreases as cells approach G2-phase, demonstration of histone H3 mRNA expression in a tumor cell population may represent responsible S-phase fraction. Thus, we have assessed S-phase fraction by nonisotopic in situ hybridization for histone H3 mRNA in paraffin sections of hepatocellular carcinomas (HCCs); then, we compared this with the histologic grades and other cell proliferative markers. In contrast to radioisotopic detection, signals were distinctly visualized, and quantitation of the stained-cells was easily carried out. Histone H3 labeling index (LI) significantly correlated with other cell proliferative markers, including Ki-67 (MIB-1) and PCNA immunostainings, and mitotic index. In addition, a statistically significant correlation was seen between histone H3 LI and histologic grades of differentiation, i.e., histone H3 LI being higher in less-differentiated HCCs. Furthermore, histone H3 LI/Ki-67 LI ratio was significantly higher in the moderately and poorly differentiated subtypes (including one case of the undifferentiated subtype) than in well-differentiated HCCs. By using this nonisotopic in situ hybridization technique, it becomes possible to assess rapidly, retrospectively, safety, and easily a malignant potentiality of HCCs in paraffin-embedded tissues.

Adult↗
PubMed1996

[Interleukin-3 therapy in patients with aplastic anemia refractory to prior therapies].

A therapeutic trial of interleukin-3 (IL-3) was carried out in four patients with aplastic anemia refractory to the prior therapies. Daily subcutaneous doses of 2.5, 5.0 or 7.5 micrograms/kg was given for 7 or 14 days. In a patient who had co- and immediate boost-administration of granulocyte colony-stimulating factor (G-CSF) and/or erythropoietin (Epo) and another who had sequential administration of G-CSF and Epo two weeks after IL-3, definite hematological response was obtained during the course after IL-3. In one patient, moderate to severe side effects consisting of facial edema, conjunctival bleeding, chills and fever, were observed after two days' administration of IL-3. Co- or sequential administration of other hemopoietic factor(s) may be essential in IL-3 therapy for aplastic anemia.

Adult↗
PubMed1996

[The production of high sensitive anti-myeloperoxidase monoclonal antibodies and their sensitivity and specificity].

We produced anti-myeloperoxidase(MPO) monoclonal antibodies(moAb) to detect MPO sensitivity in leukemic cells by visual light microscopy. We got seven kinds of moAbs which showed different properties to MPO. These antibodies reacted to MPO in immature and mature neutrophils, monocytes and HL-60(human myeloid leukemic cell line) by immunochemical detection using the avidin-biotin complex(ABC) staining method, but the amounts of immune complex products were significantly different at each moAb. MPO2, MPO4, MPO9 and MPO13 moAbs blocked MPO activities but MPO5 showed no such inhibition. Most of the moAbs reacted to 59kD MPO moAb using the western blotting method, while MPO4 and MPO5 reacted to both 81kD and 89kD MPO precursors. This data suggests that these moAbs are useful to demonstrate a small amount of MPO in leukemic cells.

Antibodies, Monoclonal↗
PubMed1996

[Evaluation of remote effect to supratentorial areas in cerebellar infarction: a semiquantitative analysis using 99mTc-HM-PAO SPECT].

We studied 18 patients with unilateral cerebellar infarction to investigate its remote effect to the supratentorial areas with 99mTc-HM-PAO SPECT. Asymmetry indexes (AI) were calculated in the cerebellum and in seven supratentorial areas (thalamus, basal ganglia, superior and inferior frontal areas, temporal area, parietal area and occipital area). Mean AIs of supratentorial areas ranged from -0.64 +/- 2.74% to +1.04 +/- 2.03%. In cerebellar infarction of acute or subacute phase, the mean AI showed larger values (+1.13%) than that of chronic phase (+0.21%), but this difference did not reach statistical significance. There was no significant difference among supratentorial AIs grouped according to cerebellar infarction size. There was also no significant correlation among AIs of cerebellar and the supratentorial areas (r = -0.32 to +0.38). Crossed hemispheric hypoperfusion is thought to be related to the interruption of cerebellocortical tracts. We concluded that the detection of the remote effect to supratentorial areas in cerebellar infarction was difficult with 99mTc-HM-PAO SPECT.

Adult↗