Lifetime measurement of the first 2(+) state in 122,124,126Ba.
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Journal Article↗
Biomedical subjects
S Ichikawa
Publications and source records attributed to S Ichikawa.
Purification of acetyl coenzyme A: deacetylacephalosporin C O-acetyltransferase from Acremonium chrysogenum.
Acetyl CoA: deacetylcephalosporin C O-acetyltransferase, which catalyzes the final step of the biosynthetic pathway to cephalosporin C, was stabilized by a buffer solution containing 7-aminocephalosporanic acid and purified over 1300-fold from Acremonium chrysogenum. The purified enzyme has a molecular weight of 55,000 as measured by gel filtration. SDS-polyacrylamide gel electrophoresis showed two subunit bands corresponding to molecular weights of 27,000 and 14,000. The enzyme has an isoelectoric point at pH 4.0 and optimum activity at pH 7.5.
Acetyltransferases↗
Role of norepinephrine in the lack of reflex tachycardia after angiotensin converting enzyme inhibitor treatment.
Angiotensin converting enzyme inhibitors decrease blood pressure without causing reflex tachycardia in hypertensives, but do not always do so in normotensives. To investigate this phenomenon, hemodynamic changes in normotensive rabbits receiving a subpressor dose of norepinephrine were studied following captopril or diltiazem treatment. We also investigated the effect of captopril on baroreceptor reflex in relation to norepinephrine infusion; the baroreflex sensitivity was determined by the relationship between mean arterial pressure and pulse interval receiving graded doses of phenylephrine. Captopril infusion decreased mean arterial pressure and pulse interval from 84 +/- 4 to 74 +/- 5 mmHg and 244 +/- 7.4 to 216 +/- 7.6 msec, respectively. In contrast, in rabbits receiving a norepinephrine infusion captopril lowered mean arterial pressure to the same extent (92 +/- 5 to 76 +/- 3 mmHg, p less than 0.05) without producing reflex tachycardia. When diltiazem was administered, reflex tachycardia occurred in rabbits both with and without a norepinephrine infusion. There was no difference in the baroreflex sensitivity between rabbits receiving norepinephrine with and without captopril treatment. However, the baroreflex curve showed a slight shift to lower pressures after norepinephrine infusion in the rabbits receiving captopril. These results suggest that elevating circulating norepinephrine might be involved in preventing reflex tachycardia after captopril.
Animals↗
Structure and distribution of the lymphatic vessels in the parietal pleura of the monkey as studied by enzyme-histochemistry and by light and electron microscopy.
The entire distribution of lymphatics in whole mount preparations of the Japanese monkey was studied using the enzyme-histochemical technique reported by KATO et al. (1990, 1991). In this staining, the lymphatic endothelium was colored dark brown by its positive 5'-nucleotidase activity, while most blood vessels (especially arterioles) were colored blue due to their positive alkaline phosphatase reaction. The whole mount preparations of the pleura treated enzyme-histochemically clearly indicated the distribution, branching patterns and running courses of lymphatic vessels. They revealed numerous short blind-ending knobs which represented the initial portions of lymphatics. These knobs were seen near the surface of the parietal pleura along its entire extent. In the costal and diaphragmatic pleura, the lymphatics ran parallel to the intercostal muscle fibers, but perpendicular to the tendinous and muscular fibers of the diaphragm; they formed ladders, independent of the courses of blood vessels. In the mediastinal pleura, lymphatic vessels showed a tree-like branching accompanying blood vessels. Under the light microscope, toluidine-blue stained semithin sections revealed the initial part of lymphatics as a small irregularly outlined cavity (7-10 microns in diameter) surrounded by a dense connective tissue. This lymphatic dilation was sometimes located close to a thin mesothelial layer. Such a structure suggesting a "stoma" was seen near the attachment of the muscular diaphragm to the sternum and along the borders of the ribs. Transmission electron microscopy revealed an occasional interruption in the mesothelium. This stoma continued to a submesothelial cavity whose base comprised an attenuated endothelium of an extended lymphatic vessel.
5'-Nucleotidase↗
Primary angiosarcoma of the right atrium detected by magnetic resonance imaging.
A 20-year-old woman with a primary angiosarcoma of the right atrium is reported. The patient had a cardiorespiratory arrest due to cardiac tamponade with bloody pericardial effusion. Magnetic resonance imaging (MRI) revealed a tumor, which was corroborated by selective coronary angiography. Open-heart surgery was performed. The tumor relapsed however, and she died four months after operation. The tumor was undetectable by echocardiography, but MRI demonstrated a heterogeneous mass with focal areas of high- and low-signal intensity in the right atrium, suggesting that MRI may allow characterization of cardiac tumors.
Adult↗
Close association of peptidergic nerves with lymphocytes in canine and monkey ileal villi.
Intimate association of peptidergic nerves with lymphocytes of canine and monkey ileal villi was demonstrated by immunohistochemistry and transmission electron microscopy. A swollen, presumably terminal, portion of nerves containing large cored vesicles and small clear vesicles was in direct contact with a lymphocyte. The apposing membranes of the nerve and lymphocyte were thickened and darkened, being separated by a narrow uniform space. The lymphocyte-associated nerves contained immunoreactivity for substance P(SP), calcitonin gene-related peptide (CGRP) or vasoactive intestinal polypeptide (VIP), localized in large-cored vessels. These result support the hypothesis that peptidergic nerves may play a regulatory role in mucosal immune responses.
Animals↗
Hepatitis virus infection (HBV and HCV) in eleven Japanese hemodialysis units.
To evaluate hepatitis C virus (HCV) and hepatitis B virus (HBV) infection in hemodialysis (HD) units, serum samples from 607 HD patients and 150 staff members at 11 HD units in Japan were collected, and were compared with those from 704 ordinary blood donors as a control. Serum samples subjected to a first generation ELISA for antibody to HCV (anti-C100-3) and were tested by ELISA for HB surface antigen (HBs-Ag), antibody to HBs-Ag, and antibody to HB core antigen (anti-HBc) as HBV markers. We also tested for HCV infection with a second generation ELISA (for antibodies to C22-3, C33c, and C100-3) in 120 HD patients and 30 staff members at 2 selected HD units. Of 607 HD patients, 104 (17%) were positive for anti-C100-3 and 221 (36%) for HBV markers, indicating a much higher prevalence of HCV and HBV infection among HD patients than among ordinary blood donors (0.9% and 18%, respectively). Of 159 patients without a history of blood transfusion, 17 (11%) were positive for anti-C100-3, showing that HCV infection can be acquired without transfusion. The incidence of anti-C100-3 varied from 0% to 53% at different HD units, and HBV markers varied from 17% to 50%. Our study detected a high prevalence of co-infection with HBV and HCV, suggesting that HCV infection may contribute to chronic liver dysfunction in HD patients. Out of 150 staff members, 3 (2%) were positive for anti-C100-3, whereas 25 (17%) were positive for anti-HBc (indicating prior HBV infection).(ABSTRACT TRUNCATED AT 250 WORDS)
Enzyme-Linked Immunosorbent Assay↗
[Continuous measurement of blood pressure variation during Kraepelin's arithmetic test and its significance in hypertensive patients].
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Adult↗
Expression of mouse tyrosine hydroxylase in Escherichia coli.
Enzymatically active mouse tyrosine hydroxylase (TH) was successfully expressed at a high level in Escherichia coli using a T7 RNA polymerase directed expression system. The specific activity of mouse TH in E. coli cell lysate was 7.5 nmol/mg protein/min. Kinetic characteristics of recombinant TH were examined. Km for tyrosine and (6R)-tetrahydrobiopterin (6R-BH4) cofactor were determined to be 7.2 microM (420 microM 6R-BH4), 19 microM [( 6R-BH4] less than 55 microM, 20 microM tyrosine) and 54 microM [( 6R-BH4] greater than 55 microM, 20 microM tyrosine), respectively. These were in good agreement with previously reported values for this enzyme.
Animals↗
Primary structure of mouse tyrosine hydroxylase deduced from its cDNA.
The cDNAs for tyrosine hydroxylase were cloned from a mouse brain cDNA library by plaque hybridization. Since the longest cDNA clone lacked approximately 150 bp sequence of its N-terminal region, additional 5' region was obtained using polymerase chain reaction. Nucleotide sequence determination of cDNAs revealed that mouse tyrosine hydroxylase m-RNA encodes 498 amino acids with a calculated molecular mass of 55,990. The amino acid sequence of mouse tyrosine hydroxylase is highly homologous to rat (97%) and human (92%) enzymes.
Amino Acid Sequence↗
Stimulation of human peripheral blood polymorphonuclear cell iodination by lignin-related substances.
Lignin is a heterogenous natural product composed of phenylpropane units and is usually associated with hemicellulose in its native state. Until now little attention has been paid to the potential therapeutic utility of lignified products. Natural lignified products are demonstrated in the present study to stimulate iodination significantly (incorporation of radioactive iodine into an acid-insoluble fraction) of human peripheral blood polymorphonuclear cells (PMN). This stimulation was significantly inhibited in the presence of myeloperoxidase inhibitors. These materials were almost completely deprived of their stimulation capacity by treatment with NaCIO2, but this capacity was not affected by severe treatment with H2SO4 or trifluoroacetic acid. Similar stimulating activity by chemically defined tannin-related polyphenolic compounds was observed. Degradation products or component units of lignin, and natural antitumor polysaccharides and their chemically modified derivatives (introduced with negatively or positively charged groups) and polysialoglycoproteins had little or no activity. The results indicate the importance of a polymerized phenolic structure for the stimulation of PMN iodination. Possible physiological relevance of the stimulation of iodination by lignified substances is discussed.
Antineoplastic Agents↗
Regulation of de novo and salvage pathways in chemotherapy.
An overview was presented of our approach of inhibition of de novo and salvage pathways in pyrimidine and purine metabolism. 1. Combination of acivicin, an inhibitor of de novo biosynthesis, and dipyridamole, a transport inhibitor, provided synergistic cytotoxicity in hepatoma and colon carcinoma cells. 2. AZT, a competitive inhibitor of the salvage enzyme, thymidine kinase, and 5-FU or MTX provided synergistic cytotoxicity in hepatoma 3924A. In human colon carcinoma HT-29 cells AZT and methotrexate yielded synergistic cytotoxicity and thymidine and hypoxanthine together provided protection from the action of these drugs. 3. These observations are significant because in rat hepatoma 3924A and in human cell lines HT-29, HL-60 and K562 thymidine kinase activity was 16- to 67-fold higher than that of dTMP synthase. Therefore, inhibition of dTMP synthase activity alone may provide poor responses because the salvage pathways can circumvent this block. 4. In leukemic patients treated with tiazofurin, an inhibitor of IMP dehydrogenase, the rate-limiting enzyme of GTP biosynthesis, and with allopurinol, which inhibits GPRT activity through raising plasma hypoxanthine levels, synergistic therapeutic results were obtained. The responses in sensitive patients entailed a decrease in IMP dehydrogenase activity and GTP concentration in leukemic cells and down-regulation of the ras and myc oncogenes. The down-regulation of the ras oncogene by tiazofurin through the decrease of GTP concentration has now been shown in K562, HL-60 and hepatoma cells and in patients with chronic granulocytic leukemia in blast crisis. Tiazofurin may be useful in studies on selective depression of the expression of the ras oncogene. 5. In 27 consecutive patients 50% responded positively to tiazofurin treatment. From this group, 10 out of 12 patients (83%) with chronic granulocytic leukemia in blast crisis responded to tiazofurin treatment.
Antimetabolites, Antineoplastic↗
Effect of saline infusion on urinary calcium excretion in essential hypertension.
Urinary excretion of sodium and calcium was examined in hypertensive (n = 8) and normotensive (n = 7) subjects following infusion of 2% saline at a rate of 11 mL/min for 90 min. The urinary sodium excretion was 204 +/- 38 (mean +/- SEM) muEq/min in normotensives and 233 +/- 28 muEq/min in hypertensives before infusion of saline and increased maximally to 499 +/- 114 muEq/min (P less than .05) and to 928 +/- 68 muEq/min (P less than .01), respectively, after saline infusion. In normotensives, urinary calcium excretion did not change significantly; however, in hypertensives excretion increased markedly (P less than .01) from 6.1 +/- 0.7 muEq/min to 12.3 +/- 1.6 muEq/min. Plasma atrial natriuretic peptide (ANP) levels increased significantly (P less than .05) in both groups. Serum ionized calcium and plasma parathyroid hormone (PTH) levels did not change significantly. The increments of urinary sodium and calcium and of plasma ANP, as well as the preinfusion plasma PTH level, were significantly (P less than .05) higher in hypertensives than in normotensives. The present study showed that exaggerated natriuresis was accompanied by hypercalcinuria and an enhanced rise in plasma ANP in hypertensives. Basal levels of plasma PTH were elevated in hypertensives. The calcium deficiency may be attributable to a close relationship between urinary sodium and calcium, and causally related to the disturbance of sodium and volume homeostasis in hypertension, which results in exaggerated natriuresis.
Adult↗
Human gnathostomiasis.
Two patients became infested with Gnathostoma nipponicum after eating raw loach-fish they had caught in a rice field in central Japan. A fragment of Gnathostoma was found in a biopsy from one of them. The sera of both patients reacted with Gnathostoma antigen using indirect immunofluorescence. Scanning electron microscopy was performed on blocks of the paraffin-embedded parasite sample and the viscera of a fish from the same rice field. The risk of eating raw freshwater fish is discussed.
Animals↗
Somatic mutation frequencies in the stamen hairs of Tradescantia grown in soil samples from the Bikini Island.
Somatic pink mutation frequencies in the stamen hairs of Tradescantia BNL 02 clone grown for 76 days in two soil samples taken from the Bikini Island (where a hydrogen bomb explosion test had been conducted in 1954) were investigated. A significantly high mutation frequency (2.58 +/- 0.17 pink mutant events per 10(3) hairs or 1.34 +/- 0.09 pink mutant events per 10(4) hair-cell divisions) was observed for the plant grown in one of the two Bikini soil samples, as compared to the control plants (1.70 +/- 0.14 or 0.88 +/- 0.07, respectively) grown in the field soil of Saitama University. The soil sample which caused the significant increase in mutation frequency contained 6,880 +/- 330 mBq/g 137Cs, 62.5 +/- 4.4 mBq/g 60Co, and some other nuclides; a 150 microR/hr exposure rate being measured on the surface of the soil sample. The effective cumulative external exposures measured for the inflorescences of the plant grown in this soil sample averaged at most 60.8 mR, being too small to explain the significant elevation in mutation frequency observed. On the other hand, internal exposure due to uptake of radioactive nuclides was estimated to be 125 mrad (1.25 mGy) as an accumulated effective dose, mainly based on a gamma-spectrometrical analysis. However, it seemed highly likely that this value of internal exposure was a considerable underestimate, and the internal exposure was considered to be more significant than the external exposure.
Micronesia↗
Immunohistochemical demonstration of peptidergic nerve fibers associated with the central lacteal lymphatics in the duodenal villi of dogs.
Immunohistochemical demonstration was made of the peptidergic nerves distributed in the central lacteal lymphatics of the canine duodenal villi. The central lacteal-associating nerve fibers were predominantly immunoreactive for both substance P (SP) and calcitonin gene-related peptide (CGRP). Observation of doubly immunostained sections evidenced that both peptides were located in one and the same nerve fibers. The SP/CGRP-immunoreactive fibers were concentrated in the intermediate portion of the villus height. Ultrastructurally, the SP/CGRP-immunoreactive nerve fibers ran closely beneath the endothelial cells of the lacteal, some of them penetrating into the cytoplasm with knob-like swellings. The immunoreactive products were localized to large-cored vesicles in the sub- and intra-endothelial nerves. The occurrence of SP and CGRP in the nerve fibers distributed in the central lacteals which lack smooth muscles implies that these nerves may be sensory in nature. A mechanoreceptive function of the nerves is proposed on the basis of their peculiar knob-like projection into the lacteal endothelium.
Animals↗
Peptidergic nerve terminals associated with the central lacteal lymphatics in the ileal villi of dogs.
Nerve fibers in the villi of the canine ileum were studied with special reference to their relation to the central lacteal. Immunohistochemically demonstrable nerve fibers containing substance P (SP) and calcitonin gene-related peptide (CGRP) were rather more numerous in the villi of the ileum than in those of the duodenum, as observed in our previous study (Ichikawa et al., 1991). They were distributed beneath the epithelium and associated with smooth muscle fibers. Besides these localizations, immunoreactive fibers were gathered, especially at the middle of the height of the villus, close to the endothelial cells of the central lacteal. This particular distribution of nerves was more evident in the ileum than in the duodenum. Electron microscope observation indicated beaded fibers containing large cored (peptidergic) and small clear vesicles coursing closely under the lacteal endothelium, partly intercalated by a basement membrane and partly in direct contact. The nerve fibers often penetrated the endothelial cell, being directly surrounded by its cytoplasm. Although the above-described findings essentially coincide with our previous observations in canine duodenum (Ichikawa et al., 1991), the present study in the ileum demonstrated occasional nerve fibers protruding into the lacteal lumen with a knob-like swelling. It is suggested that the SP and CGRP-containing nerves in problem might be sensory in nature, possibly monitoring mechanical information from the lumen and wall of the central lacteal. At the same time, these nerves are suggested to be secretory in nature, releasing the peptides to exert unknown effects upon the lacteal wall and its vicinity, presumably in response to luminal and mural stimuli.
Animals↗
HLA typing using IL-2 activated T lymphocytes: usefulness in pediatric candidates for allogeneic bone marrow transplantation.
Following a preliminary study in healthy blood donors, we have performed serological HLA-A, B, C, DR and DQ typing using recombinant IL-2 activated T lymphocytes (IL-2.aTLs) in pediatric candidates for allogeneic bone marrow transplantation. In such patients, it is often difficult to obtain the quantity of lymphocytes required for HLA typing, particularly for class II typing using B lymphocytes, considering the timing of sampling and the volume of blood to be collected. Peripheral blood mononuclear cells (PBMCs) were activated and expanded with IL-2 until a sufficient number of IL-2.aTLs of good viability were available for the typing. In the first 10 cases, analyses of surface markers (CD2, CD20, CD25, CD36, HLA-DR and HLA-DQ, CD2/HLA-DR: two color) of IL-2.aTLs were done using flow cytometry at the time of HLA typing and indicated that IL-2.aTLs expressed HLA-DR and DQ antigens sufficient for evaluation. A small number (less than 10(6] of fresh or cryopreserved PBMCs, even those containing leukemic blast cells, were sufficient to induce and expand IL-2.aTLs for HLA typing. To date we have been able to successfully HLA-A, B, C, DR and DQ type 20/20 pediatric candidates. The HLA antigens identified on the patients' IL-2.aTLs were confirmed by a family study.
Adolescent↗