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Biomedical subjects

H Koide

Publications and source records attributed to H Koide.

At least 271 records · Page 15Linked to original sources
PubMed1988

Aminotransferase activity in the liver of diabetic mice.

Enzyme activity in the livers of mice was studied in examining the metabolic disturbances of diabetes. Spontaneously non-obese diabetic (NOD) mice, mice with alloxan-induced diabetes (Allo), and control ICR mice were used. As NOD mice undergo a spontaneous pathogenic process over time, younger and older NOD mice were compared (non-diabetic and diabetic) as were control ICR mice. Two liver enzymes became more active with age, aspartate aminotransferase (AST) and alanine aminotransferase (ALT). AST activity increased more in the hyperglycemic mice, i.e., the diabetic NOD and the Allo mice, than in the normoglycemic group, i.e., the ICR and non-diabetic NOD mice. Abnormally high AST activity was seen in the cytosolic fraction of the liver but not in the mitochondrial fraction. The changes in enzyme activity in diabetic mice were independent of any age-associated changes. The higher AST levels in diabetic mice are thought to be consistent with their greater need for gluconeogenic substrate. AST showed a more notably higher increase than did ALT in this study, and lactate dehydrogenase showed no significant changes.

Aging↗
PubMed1988

Biosynthesis of a protein containing a nonprotein amino acid by Escherichia coli: L-2-aminohexanoic acid at position 21 in human epidermal growth factor.

Endeavoring to develop a method to biosynthesize proteins substituted with nonprotein amino acids, we attempted the incorporation of L-2-aminohexanoic acid (Ahx) into human epidermal growth factor (hEGF). Escherichia coli YK537 strain harboring plasmid pTA1522, which has the phoA promoter-phoA signal peptide-hEGF gene, was used. Cells were cultured first in high-phosphate medium and then, for induction of the hEGF-encoding gene, transferred to low-phosphate medium containing Ahx (0.25 mg/ml). hEGF and Ahx-substituted hEGF, [Ahx21]hEGF, secreted into the periplasm were recovered. After treatment with H2O2, [Ahx21]-hEGF was clearly separated from methionine-oxidized hEGF by one-step reverse-phase HPLC. Substitution of the methionine residue of hEGF with Ahx was confirmed by the amino acid analysis of [Ahx21]hEGF. The three biological activities of [Ahx21]hEGF were the same as those of hEGF. From the successful production of [Ahx21]hEGF, a basic strategy was established for preparing proteins substituted with nonprotein amino acid (alloprotein). Induction of the phoA promoter of pho regulon and secretion of the product to the periplasm may depress heat shock-like responses and subsequent hydrolysis of the product by cytoplasmic protease.

Aminocaproates↗
PubMed1988

Analysis of ras gene expression in stomach cancer by anti-ras p21 monoclonal antibodies.

Using anti-ras p21 monoclonal antibodies, RASK-3, which reacts with all of Ki-, N-, and Ha-ras p21, we examined by immunohistochemistry the expression of p21 in human gastric cancer (80 cases) and benign gastric lesions (32 cases). Ten percent formalin fixed tissues were studied. Ras p21 was positive in 51 cases (64%) out of 80 cases and partially positive in 12 cases (15%) at the cancerous areas. Ras p21 was partially positive in 7 cases (9%) at the noncancer areas of the same slides. Intestinal metaplasia and normal parietal cells were also often positive. In the study of 32 cases of benign stomach lesions, 2 out of 3 cases of atypical hyperplasia (ATP) and 3 out of 11 cases of stomach ulcer with regenerating epithelials were positive. Ras p21 was more dominantly expressed in the well-differentiated type of stomach cancer than the poorly differentiated type. Expression of ras p21, however, was not correlated either with the grades of cancer invasion or with the types of cancer infiltration.

Antibodies, Monoclonal↗
PubMed1988

Value and limitation of stress thallium-201 single photon emission computed tomography: comparison with nitrogen-13 ammonia positron tomography.

The diagnostic value of exercise 201Tl single photon emission computed tomography (SPECT) for assessing coronary artery disease (CAD) was comparatively evaluated with exercise [13N] ammonia positron emission tomography (PET). Fifty-one patients underwent both stress-delayed SPECT imaging using a rotational gamma camera and stress-rest PET imaging using a high resolution PET camera. Of 48 CAD patients, SPECT showed abnormal perfusion in 46 patients (96%), while PET detected perfusion abnormalities in 47 (98%). The sensitivity for detecting disease in individual coronary arteries (greater than 50% stenosis) was also similar for SPECT (81%) and PET (88%). When their interpretations were classified as normal, transient defect, and fixed defect in 765 myocardial segments, SPECT and PET findings were concordant in 606 segments (79%). However, 66 segments showed a fixed defect by SPECT but a transient defect by PET, whereas there were only nine segments showing a transient defect by SPECT and a fixed defect by PET. PET identified transient defects in 34% of the myocardial segments showing a fixed defect by SPECT. We conclude that both stress SPECT and PET showed high and similar sensitivities for detecting CAD and individual stenosed vessels. Since stress-delayed SPECT with single tracer injection detected fewer transient defects, it may underestimate the presence of myocardial ischemia, compared with high resolution PET imaging with two tracer injections.

Adult↗
PubMed1988

Monoclonal antibodies against laminin A chain and B chain in the human and mouse kidneys.

Three monoclonal antibodies against laminin A and B chains derived from mouse EHS sarcoma were isolated and designated Lam 1, Lam 2, and Lam 3. Lam 1 recognized laminin A and B chains, whereas Lam 2 and Lam 3 reacted with only A chain. By using the immunofluorescence method, three monoclonal antibodies equally stained the human skin basement membrane and Descemet's membrane of cornea. In the kidney, however, these monoclonal antibodies showed the different distribution; Lam 1 stained the glomerular basement membrane, the mesangium, Bowman's capsule, and the tubular basement membrane in the mouse kidney. In the human kidney, Lam 1 stained the mesangium very slightly bud did not stain the glomerular basement membrane. Both Lam 2 and Lam 3 stained the mesangium, Bowman's capsule, and proximal tubular basement membrane in the mouse kidney. In the human kidney, however, Lam 2 stained the mesangium and slightly stained the glomerular basement membrane, although Lam 3 stained only the mesangium. Oxidation of the kidney sections by sodium periodate changed the staining pattern of Lam 2 and Lam 3 in the human kidney, whereas it did not change the staining pattern of Lam 2 and Lam 3 in the mouse kidney.

Animals↗
PubMed1987

Detection of coronary artery disease with 13N-ammonia and high-resolution positron-emission computed tomography.

In order to evaluate the detectability of coronary artery disease (CAD) with positron-emission computed tomography (PET), we performed 13N-ammonia myocardial PET scanning at rest and with exercise loading in 20 normal subjects and 40 patients with CAD, by means of a high-resolution, multi-slice, whole-body PET scanner. Myocardial PET scanning was performed 3 minutes after injection of 13N-ammonia at rest and during exercise. The circumferential profile analysis of resting PET images revealed regional hypoperfusion in 96% of CAD patients with previous myocardial infarction and in 29% of those without infarction. Exercise PET studies showed high sensitivity (93%) in detecting CAD without myocardial infarction, whereas no abnormal hypoperfusion was detected in normal subjects. Segmental analysis of regional myocardial perfusion with exercise stress identified 67 of 75 stenosed vessels (89%). We conclude that 13N-ammonia myocardial PET with exercise loading provides high-quality tomographic images of regional myocardial perfusion and is a valuable technique for detecting CAD.

Adult↗
PubMed1987

Noninvasive method to assess cor pulmonale in patients with chronic obstructive pulmonary disease.

In our study of 15 patients with chronic obstructive pulmonary disease, we performed myocardial perfusion single-photon-emission computerized tomography (SPECT) with thallium-201 to quantitatively assess right ventricular hypertrophy. On the SPECT images, we determined the ratio of activity in the right-to-left ventricular wall as the thallium score. Right ventricular ejection fraction (RVEF) was measured by multigated equilibrium radionuclide ventriculography with krypton-81m. Both the thallium scores and RVEF values correlated well with pulmonary arterial pressure (r = 0.65 and r = -0.86, respectively) and permitted the structural and functional assessment of cor pulmonale. When the patients were classified according to the thallium scores and RVEF values, those who had both a high thallium score and reduced RVEF had a significantly high pulmonary arterial pressure and vice versa. The combined evaluation of the thallium score and RVEF enabled accurate noninvasive assessment of cor pulmonale.

Adult↗
PubMed1986

Ultrastructural localization of lectin receptors in the monkey retinal photoreceptors and pigment epithelium: application of lectin-gold complexes on thin sections.

The cell surface and intracellular binding sites of two lectins, wheat germ agglutinin (WGA) and Ricinus communis agglutinin-1 (RCA-1), in the monkey retina were investigated at the ultrastructural level by means of post-embedding staining of Lowicryl K4M-embedded specimens with lectin-colloidal gold complexes. Effects of pretreatment with neuraminidase were also studied. The techniques enabled us to detect lectin binding sites in the various intracellular compartments of photoreceptor cells, retinal pigment epithelium (RPE), and interphotoreceptor matrices. Wheat germ agglutinin, which recognizes N-acetylglucosamine and sialic-acid residues, showed a prominent and uniform binding to the disc membranes of rod outer segments (ROS), rod connecting cilia, interphotoreceptor matrices, and RPE microvilli. The intensity of these binding sites was markedly reduced when thin sections were pretreated with neuraminidase, except the labeling of ROS disc membranes. Cones were labeled sparsely. The staining of phagosomes in the RPE cytoplasm did not change after neuraminidase digestion. RCA-1, which recognizes galactose residues, revealed a moderate binding to the ROS disc membranes, with a noticeably greater intensity of binding to the basal region of ROS disc membranes. With neuraminidase treatment heavier binding with RCA-1 occurred in interphotoreceptor matrices, connecting cilia and RPE microvilli, whereas there was no significant alteration in binding to the ROS disc membranes. Phagosomes in the RPE were also labeled with this lectin. The results suggest the presence of sialic acid and galactose as the constituent carbohydrates of glycoconjugates in the interphotoreceptor matrices and RPE microvilli.

Animals↗
PubMed1986

Acute posterior multifocal placoid pigment epitheliopathy associated with diffuse retinal vasculitis and late haemorrhagic macular detachment.

A 20-year-old healthy man suffered rapid loss of bilateral central vision with placoid lesions at the level of the retinal pigment epithelium and choriocapillaris scattered in the posterior pole of the fundus. In addition, acute vasculitis of the retinal veins was remarkable and widespread throughout the posterior pole and midperiphery. These inflammatory signs subsided in several weeks and were succeeded by recovery of the normal visual acuity with residual pigment derangements in the deep retina. Sixteen months after the onset of the disease choroidal neovascular membranes developed in the macular region of the left eye, followed by haemorrhagic macular detachment and marked visual loss. Significant increases in the serum cold agglutinin titre occurred as isolated laboratory findings concurrently with the acute stage of the disease and the late macular complication, though no clinical or other laboratory sign suggested viral infection.

Adult↗
PubMed1986

Purification of antibody against peanut agglutinin-receptors of bovine interphotoreceptor matrix.

From rabbit antiserum against peanut agglutinin (PNA)-receptors of the bovine interphotoreceptor matrix, an antibody was isolated by immunoaffinity chromatography on immobilized PNA-receptors. The antibody reacted with the bovine interphotoreceptor matrix at the molecular weight of 130,000 daltons. Immunohistochemical studies revealed that the antibody was bound not only to the surfaces of the cone photoreceptor cells but also to the surfaces of the rods, suggesting that the antibody purified here may have been formed by the major structure of glycoprotein that is common in the interphotoreceptor matrix around the cones and rods.

Animals↗
PubMed1986

Interpolating scan and oblique-angle tomograms in myocardial PET using nitrogen-13 ammonia.

The effect of low sensitivity areas or gaps between adjacent slices of the multislice positron emission tomography on detection of myocardial perfusion abnormality with 13NH3 was evaluated segmentally in 36 patients with coronary artery disease at rest or during exercise. The detectability of the defects in RCA or LAD region was 80% in single-position scans in stress studies. The false-negative defects were located mainly in the inferior wall, apicoinferior wall, or high anterior wall. When the patients were moved half the slice interval to perform the interpolating scan, and the two sets of images were interlaced with each other, the detectability increased to 88%. The interpolating scan also allowed reconstruction of long-axis and short-axis tomograms in high quality, which further improved the detectability of perfusion defects (100% for RCA or LAD and 75% for LCX lesion) and helped in understanding the anatomic relationships to the coronary artery territories.

Ammonia↗