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Biomedical subjects

T Uchida

Publications and source records attributed to T Uchida.

At least 1,225 records · Page 68Linked to original sources
PubMed1982

[Study on right and left atrial dynamics in chronic constrictive pericarditis by esophageal echocardiography].

In 9 normal subjects (N) and 4 patients with chronic constrictive pericarditis (CP) with normal sinus rhythm, esophageal echocardiography was performed to obtain simultaneous echograms of the right atrial free wall and the interatrial septum, and both atrial dynamics were evaluated. In spite of increased mean right atrial and mean pulmonary arterial wedge pressures in CP, there were no significant differences in left, right and total atrial end-diastolic dimensions between N and CP. This indicates that there is a decrease in compliance of atrio-pericardial system in CP. Atrial shortening of both atria during active atria contraction was decreased in CP, while there was no significant difference in atrial dimension measured at the beginning of the active atrial shortening between N and CP. This impaired pump function might be due to increased ventricular late-diastolic pressure or organic change in the atrial muscle. The passive enlargement of both atria was impaired during atrial filling phase in CP. Thus, it was concluded that in CP the active shortening and passive enlargement of the right and left atria are decreased, and the atria tend to be a conduit.

Adult↗
PubMed1982

[Diagnosis of right atrial infarction by esophageal echocardiography].

Atrial infarction is rare and its ante mortem diagnosis is difficult by electrocardiography. There has been no report concerning the diagnosis of atrial infarction by echocardiography because it is difficult to observe atrial motion by conventional echocardiography. This report deals with a case of probable right atrial infarction diagnosed by esophageal echocardiography. A 50-year-old man was admitted to our hospital under the diagnosis of acute infero-posterior myocardial infarction. Swan-Ganz catheterization data revealed dip and plateau pattern with elevated right atrial pressure suggesting complicated right ventricular infarction. In the esophageal echocardiograms recorded one month later, the motion of the right atrial anterior wall was akinetic and right atrial dimension did not change during both atrial contraction phase and atrial filling phase. These findings suggest impairment of pump function and reservoir function of the right atrium. Amplitudes of the interatrial septum during atrial filling phase and atrial contraction phase were in the lower limit of normal range. Total occlusion of the right coronary artery was proven by coronary arteriography. Hypokinesis of the upper right atrial appendage was suspected by right atriography and maximal right atrial volume was as large as 116 ml. In the right atrial volume curve by cardiac scintigraphy, fractional emptying was as low as 28%. The patient had an uneventful recovery and returned to full-time works, so that pathological diagnosis was not obtained, but the clinical diagnosis of right atrial infarction was strongly suspected by the clinical findings mentioned above. It was concluded that the esophageal echocardiography is mandatory to observe atrial wall motion abnormality whenever atrial infarction is suspected.

Echocardiography↗
PubMed1981

Plant prolyl hydroxylase recognizes poly(L-proline) II helix.

Substrate specificity of a prolyl hydroxylase from Vinca rosea suspension-cultured cells was studied using synthetic oligo(L-proline)s and their t-butyloxycarbonyl derivatives (Pron and Boc-Pron; n = 2-8) as peptidyl substrates. All peptides with a residual number of 5 or greater served as substrates in the enzyme reaction at 30 degrees C, after the preincubation of the enzyme and peptides at 0 degrees C prior to addition of cofactors and cosubstrate. Under the same conditions, the hydroxylation of Pro5 reached a plateau within 10 min, but that of Boc-Pro8 and poly(L-proline) increased linearly up to 40 min. If the preincubation temperature was raised to 30 degrees C, only Pro5 among the peptides was unable to serve as a substrate. The optimum temperature of the enzyme was 30 degrees C toward Boc-Pro8 and poly(L-proline) but it decreased to 15 degrees C using Pro5. These data suggest that the enzyme can bind Pro5 only at low temperature. Poly(L-proline) and Boc-Pron (n greater than or equal to 5) in aqueous solution are known to have a left-handed helical structure (poly(L-proline) II helix). Moreover, Pro5 was indicated as forming this helix below 10 degrees C. Accordingly, the enzyme recognizes the poly(L-proline) II helix, that is, the secondary structure of a substrate rather than the primary structure.

Circular Dichroism↗
PubMed1981

Immunoperoxidase study of alkaline phosphatase in testicular tumor.

Indirect immunoperoxidase staining was carried out on human testicular tumors using monospecific antibodies against placental (Regan) and intestinal isoenzymes of alkaline phosphatase (ALPase). The very high incidence of seminoma (approximately 90%) revealed positive staining of placental ALPase mainly on the cell membrane of tumor cells, whereas none of the seminoma showed presence of intestinal isoenzyme. Placental isoenzyme was not recognized in any embryonal carcinoma and interstitial cell tumor. The epithelial cells of the glandular elements of teratoma occasionally exhibited strong staining for intestinal ALPase and weak staining for placental ALPase. The appearance of Regan isoenzyme in seminomas might be considered possible conversion of hepatic to placental isoenzyme, a consequence of malignant transformation of spermatogenic cells. Regan isoenzyme appears to be a new tumor marker for seminoma and the frequent identification of Regan isoenzyme in seminoma may disclose a unique biologic characteristic of this germinal tumor.

Adult↗
PubMed1981

Immunohistochemical localization of galactocerebroside in kidney, liver, and lung of golden hamster.

Localization of galactocerebroside in kidney, liver, and lung of hamster was studied by the immunoperoxidase method using an affinity-purified specific antibody. Epithelial cells of the following anatomical sites were labelled with the antibody: distal tubuli, ascending limbs of Henle's loops, and collecting tubuli in kidney; periportal bile ducts and hepatic parenchyma in liver; bronchioli and alveoli in lung. The existence of galactocerebroside in these 3 organs was also confirmed by chemical analysis.

Animals↗
PubMed1981

Gonadotropin and alkaline phosphatase producing occult gastric carcinoma with widespread metastasis of generalized bone.

A case is reported of a small primary occult gastric adenocarcinoma occurring in a 57-year-old man revealing widespread metastasis to generalized bone, and associated with high serum level of circulating human chorionic gonadotropin (hCG), carcinoembryonic antigen (CEA), and alkaline phosphatase (ALPase). The primary site of metastatic bone tumor was not clear until autopsy. Microscopic examination of the gastric primary revealed moderately differentiated tubular adenocarcinoma admixed with numerous signet-ring carcinoma cells without conspicuous trophoblastic differentiation. The elaboration of hCG and intestinal and placental isoenzyme of ALPase by carcinoma cells themselves was confirmed by the indirect immunoperoxidase method. The present case may be interesting because of unusual metastasis and simultaneous production of hCG, CEA, and intestinal and placental ALPase isoenzymes.

Adenocarcinoma↗
PubMed1981

Substrate specificity of alpha-L-arabinofuranosidase from plant scopolia japonica calluses and a suggestion with reference to the structure of beet araban.

Substrate specificity of alpha-L-arabinofuranosidase from plant Scopolia japonica was examined using three kinds of arabinodisaccharides prepared from natural sources of synthetically. This enzyme hydrolyzed arabinofuranosyl-arabinoses which had either an alpha-(1 leads to 3) or a alpha-(1 leads to 5) linkage, but hydrolyzed arabinopyranosyl-arabinose having a alpha-(1 leads to 5) linkage to a lesser degree. alpha-L-Arabinofuranosidase (alpha-L-arabinofuranoside arabinofuranohydrolase, EC 3.2.1.55), which was shown by us to be an exo-enzyme, degraded beet araban incompletely. Arabinose oligomers and galactose-containing fragments, isolated following acid hydrolysis of araban, were both incompletely degraded by the enzyme. The reasons for the incomplete degradation were explained by the novel finding of (1 leads to 2) linkages and arabinopyranosides and the inclusion of trace amounts of galactose into the carbohydrate chain of araban. This enzyme was practically non-reacting with the hydroxyprolyl-arabinose linkage of glycopeptides from plant cell walls.

Carbohydrate Conformation↗
PubMed1981

Evidence for guanylate cyclase activity associated with hemagglutinating virus of Japan (Sendai virus).

Purified virions of HVJ (Sendai virus) were found to contain a guanylate cyclase activity that converts GTP to cyclic GMP. Activities of adenylate cyclase and 5'-nucleotidase which are frequently used as marker enzymes of cell membranes were not detected in the virus. Guanylate cyclase and virion-associated activities, neuraminidase and hemagglutinin, were co-purified during a purification of virions. Guanylate cyclase activity was not detected without disruption of the virions with a detergent, Triton X-100 or Nonident P-40. Treatment of intact HVJ with a proteolytic enzyme, trypsin or chymotrypsin, destroyed both neuraminidase and hemagglutinin; however, most of the guanylate cyclase ws retained. Guanylate cyclase activity was found in fractions containing nucleocapsids after sucrose density gradient centrifugation of disrupted virions. These results indicated that the enzyme was tightly bound to cores of HVJ and, therefore, its presence could not be explained by binding of host cell enzyme to the surface of virions. Properties of the virus-derived enzyme and particulate fractions of host cell homogenates were similar. Antiserum against nucleocapsids of HVJ inhibited guanylate cyclase activity of HVJ and particulate fractions of cells such as chorioallantoic membrane and rat liver, while soluble guanylate cyclase was not inhibited by antiserum. The biological significance and origin of guanylate cyclase found in HVJ are obscure and await further study.

Electrophoresis, Polyacrylamide Gel↗
PubMed1981

3',5'-Cyclic nucleotide phosphodiesterase activity of the sulphatase A of ox liver.

The sulphatase A (aryl-sulphate sulphohydrolase, EC 3.1.6.1) of ox liver hydrolyses adenosine 3',5'-monophosphate (cyclic AMP) to adenosine 5'-phosphate at an optimum pH of approx. 4.3, close that for the hydrolysis of cerebroside sulphate, a physiological substrate for sulphatase A. The Km is 11.6 mM for cyclic AMP. On polyacrylamide gel electrophoresis sulphatase A migrates as a single protein band which coincides with both the arylsulphatase and phosphodiesterase activities, suggesting that these are due to a single protein. Cyclic AMP competitively inhibits the arylsulphatase activity of sulphatase A, showing that both activities are associated with a single active site on the enzyme. sulphatase A also hydrolyses guanosine 3',5'-monophosphate, but not uridine 3',5'-monophosphate nor adenosine 2',3'-monophosphate.

2',3'-Cyclic-Nucleotide Phosphodiesterases↗
PubMed1981

Methylamine stimulates the action of ricin toxin but inhibits that of diphtheria toxin.

The action of ricin toxin was stimulated by addition of methylamine or some other amines, as shown by measuring the inhibition of protein synthesis of cultured cells by the toxin. Under the same conditions, however, the action of diphtheria toxin was completely inhibited by the amines. In a cell-free protein-synthesizing system, methylamine had no effect on the action of the A chain of ricin toxin and fragment A of diphtheria toxin. Studies on the interactions of 125I-labeled toxins with cells revealed that methylamine did not alter toxin-receptor bindings, but affected the entry of the toxins into the cells. Studies were also made on the effects of methylamine on the actions of two hybrid toxins, formed from a subunit of Wistaria floribunda lectin and fragment A of diphtheria toxin and the A chain of ricin toxin, respectively. Results suggested that the processes of entry of ricin toxin and diphtheria toxin, or at least parts of these processes, are different.

Cell-Free System↗
PubMed1981

A silent period in sural muscle occurring prior to the voluntary forward inclination of the body.

A silent period lasting for 300-500 msec was observed in triceps surae muscle when the subject inclined forward from the normal standing. This silent period preceded 100 msec or more the beginning of the body inclination and was terminated by an abrupt refiring in the midst of the body swing. The silence was not preceded by the increase in activity of the sural muscle itself or any other leg muscles studied. H-reflex in soleus was strongly inhibited or disappeared during the silent period, indicating that the excitability of the spinal motoneurons was greatly decreased during this period. These findings suggest that the silent period was not induced by some reflex activity in the spinal cord, but was caused by the inhibitory activity based on a central program on the spinal motoneurons.

Adult↗
PubMed1981

Fluorospectroscopic studies of various ganglioside and ganglioside--lecithin dispersions. Steady-state and time-resolved fluorescence measurements with 1,6-diphenyl-1,3,5-hexatriene.

Molecular motions of 1,6-diphenyl-1,3,5-hexatriene (DPH) in gangliosides (GM3, GM2, GM1, GD1a, and GD1b), GA1 glycosphingolipid, and dipalmitoyl-sn-glycero-3-phosphorylcholine (DPPC)--ganglioside mixed dispersions were studied by using techniques of steady-state and nano-second time resolved fluorescence measurements in the temperature range of 20--50 degrees C. The total fluorescence decay s(t) was approximated to a best-fit curve of double-exponential decays, and two fluorescence lifetimes were obtained. The values of the shorter fluorescence lifetime in dispersions composed of a single glycosphingolipid component approached those of the longer one on addition of DPPC. The molecular arrangement or microheterogeneity of the hydrocarbon region surrounding DPH molecules changed depending on the ratio of DPPC to ganglioside molecules and on the temperature. The steady-state anisotropy rs in dispersions composed of a single glycosphingolipid component exhibited smooth changes, not abrupt ones, in the temperature range, in contrast to that in DPPC liposomes. In the various glycosphingolipid dispersions studied, the motion of DPH molecules was the most restricted in the GA1 dispersion. Sialic acid linked to the neutral sugar backbone influenced the hydrophobic region and increased the motion of DPH molecules. In the gangliosides tested, the motion of DPH molecules in the hydrophobic region of GM1 ganglioside was found to be the most restricted. These comparative studies indicate that the ultimate and/or penultimate carbohydrate moieties of the neutral sugar backbone of gangliosides and the topographical difference in the locations of the sialic acid linkage influence the integrity of the membranes including the hydrophobic region.

Animals↗