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Biomedical subjects

M Iwamoto

Publications and source records attributed to M Iwamoto.

At least 307 records · Page 17Linked to original sources
PubMed1989

Interleukin 1: a regulator of chondrocyte proliferation.

Human interleukin 1 beta (IL-1 beta), at low concentrations (0.3-1 ng/ml), decreased by 95% the efficiency of colony formation in soft agar by rabbit articular chondrocytes. Furthermore, interleukin 1 (IL-1) suppressed by 50-60% the incorporation of [3H]thymidine into DNA in high density chondrocyte cultures on plastic dishes in the presence of 10% serum or fibroblast growth factor, although it increased twofold this incorporation in 0.3% serum alone. This suggests that IL-1 directly inhibits mitogenic response of differentiated chondrocytes to growth factors. In contrast, IL-1 stimulated [3H]thymidine incorporation into DNA in rabbit fibroblasts in the presence of growth factors. The selective suppression of chondrocyte replication by IL-1 may play an important role in cartilage destruction associated with chronic inflammatory joint diseases.

Animals↗
PubMed1989

[A case of sepsis and meningitis due to capsule-deficient Cryptococcus neoformans with SIADH].

Capsule-deficient Cryptococcus neoformans (CN-CD) infection is very rare. The authors recently experienced the case of CN-CD infection with the complication of the syndrome of inappropriate antidiuretic hormone secretion (SIADH) in a 83 year old woman. She was admitted to our hospital with the complaints of fever and general fatigue on June 10, 1987. At the time of admission, there were no abnormal findings except a mildly lowered consciousness level on physical examination, there were no abnormal neurological finding nor meningeal signs. Laboratory data revealed a mild leukocytosis and hyponatremia. Chest X-P showed a few small nodular shadows scattered in both lungs. Antibiotics therapy was of no help and hyponatremia became worse. Then with the suspicion of SIADH, Demeclocycline was administered and limitation of water intake was decreased and hyponatremia improvement was used. Yeast-like fungi was detected in the venous blood culture and in the cerebrospinal fluid (cell count: 252/3) CN-CD by India-ink preparation and bacteriological nature were determined. We made a diagnosis of sepsis and meningitis by CN-CD accompanied with SIADH. In spite of Miconazole administration intravenously and intrathecally, she died 2 months after admission. The minimal inhibitory concentration (micrograms/ml) of antibiotics against the isolated CN-CD was as follows: Amphotericin B: 0.78, 5-PC: 1.56, Miconazole less than or equal to 0.05, Nystatin: 25, Ketoconazole: 0.78.

Aged↗
PubMed1989

Reevaluation of nonstress test by umbilical venous blood profile using cordocentesis.

Fetal blood sampling by cordocentesis was performed in 85 cases of fetuses with either nonimmune hydrops fetalis, anomalies, intrauterine growth retardation, maternal immunological disorders, Rh incompatibility, hydronephrosis, polyhydramnios, maternal preeclampsia or fetal tumor. Fetal heart rate monitoring was also recorded before cordocentesis. We evaluated the usefulness of the nonstress test (NST) with regard to fetal hematologic gas profiles including pH, pO2 and pCO2. When the acceleration was classified into reactive and nonreactive group, pH and pO2 were significantly higher in the reactive group than in the nonreactive group. pCO2 was significantly lower in the former than the latter. However, the sensitivity and specificity of the reactive NST predicting fetal umbilical venous pO2 over 20 mm Hg was 79.7 and 68.7%, respectively. The false-positive rate of nonreactive NST predicting hypoxemia below 20 mm Hg pO2 was 44%. As a consequence, we cannot always rely on the NST, and should perform fetal blood sampling to assess fetal condition for further management.

Carbon Dioxide↗
PubMed1989

Phosphatase-inhibitory activity and activation of murine macrophages by new 5'-nucleotidase inhibitors, NPF-86IA, NPF-86IB, NPF-86IIA and NPF-86IIB.

New 5'-nucleotidase-inhibitory polyphenols named NPF-86IA, NPF-86IB, NPF-86IIA and NPF-86IIB were isolated from the seeds of Areca catechu L. The ability of the inhibitors to precipitate gelatin was investigated by microturbidimetry. These inhibitors produced weak turbidity. As 5'-nucleotidase is a kind of phosphatase, we examined the effects of these inhibitors on alkaline and acidic phosphatases. While they showed moderate inhibitory effects on the activity of acidic phosphatases, they did not have any significant effect on the activity of alkaline phosphatase. Therefore, they showed a higher inhibitory effect on the 5'-nucleotidase than the other phosphatases, Murine macrophages were directly stimulated by the 5'-nucleotidase inhibitors.

5'-Nucleotidase↗
PubMed1989

Vascular dilatory action of the Chinese crude drug. II. Effects of scoparone on calcium mobilization.

Further experiments were conducted to examine the effect of scoparone (6,7-dimethoxycoumarin), a coumarin derivative found in the Chinese crude drug "Capillaris Flos," on calcium mobilization. Scoparone does not affect Ca2+ influx through the voltage-dependent channel due to membrane depolarization. Its inhibitory action may be dependent not only on the inhibition of Ca2+ release from sarcoplasmic reticulum but also on the inhibition of extracellular Ca2+ influx through the receptor-operated channel.

Animals↗
PubMed1989

[A study of the state-trait anxiety inventory (STAI) and its application to noise stress].

By using the STAI developed by Spielberger et al. we have investigated the validity and reliability of two scales, that is, State Anxiety (A-State) and Trait Anxiety (A-Trait), and at the same time have examined them under various conditions. The results obtained are as follows: 1) As a result of factor analysis concerning 40 items of the STAI used in this research, we have confirmed that both A-State and A-Trait have independent factor structures of their own, and that the items of the scales also carry their own validity. 2) After due consideration of the test-retest reliability of the two scales, we have found that A-Trait has rather high stability. Moreover, we have noticed that Cronbach's alpha coefficients, which show the reliability of the two scales, are high. In consequence, we have confirmed the high reliability of the two scales. 3) In comparing the scores of A-State and A-Trait obtained from young healthy people with those from healthy aged people, we have noticed that the aged get low scores on each of the two scales, and that each score distribution shows an excellent fit to the normal one. 4) We have found that A-State scores go up significantly when people are in a condition of emotional stress, but that there is not any change of A-Trait scores. 5) We have observed a significant increase of A-State scores at each noise level over 75 dB(A).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1989

Alteration of FHR pattern and cerebral metabolic rate of glucose of the fetus measured by positron emission tomography during progress of acidemia. The significance of overshoot acceleration in FHR.

In order to investigate the significance of overshoot acceleration in FHR with acidosis induced by serial cord compression, cerebral glucose metabolic rate (CMRglc) was measured in four chronically instrumented fetuses before cord compression and immediately after appearance of the overshoot acceleration in FHR. The investigation of CMRglc was carried out using positron emission tomography to assess accumulation of cyclotron-produced F18-FDG in the fetal brain. CMRglc in the fetal brain in the nonacidemic condition was 1.73 mg/100 g/min. In acidemia, with fetal arterial pH near 7.15 in which FHR showed the characteristic pattern with overshoot acceleration, CMRglc was significantly decreased to 0.73 mg/100 g/min. We concluded that, to avoid neuronal damage, it is necessary to intervene when the fetal condition deteriorates to the extent that overshoot acceleration in FHR occurs.

Acidosis↗
PubMed1989

[Lymphoepithelial cyst of the upper neck: report of a case].

A case of lymphoepithelial cyst of the upper neck is presented. The patient was a 77-year-old woman. After her lesion was extirpated under clinical diagnosis of salivary gland tumor, identified as lymphoepithelial cyst (so-called branchial cyst). Histopathologically salivary gland was observed in the cyst wall composed of lymphoid tissue and was demonstrated highly active amylase-enzyme (S type) in the cyst fluid. These findings are convicted that our case originates ductal epithelium entrapped in cervical lymph node (inclusion theory of Bhaskar).

Aged↗
PubMed1989

[A case of acute myeloblastic leukemia associated with multiple intracerebral hematomas].

A case of acute myeloblastic leukemia associated with multiple intracerebral hematomas is presented. A 19-year-old woman with a two week's history of mild fever suddenly lost consciousness, and was afflicted right severe hemiparesis, left mild hemiparesis and motor aphasia. A CT scan revealed bilateral thalamic hyperdense lesions and paraventricular small hematoma in the right hemisphere. Hematology showed marked leukocytosis (450,000/mm3), mild anemia and no coagulopathy including disseminated intravascular coagulation syndrome. Cytology showed myeloblasts with positive stain in peroxidase and negative in esterase both in cerebrospinal fluid and blood. These findings indicated M 1 type, myeloblastic leukemia without maturation, according to FAB (French-American-British Co-operative group) classification. CT scan on the second day demonstrated expansion of the hematoma in the right thalamus, and nine brand-new small hematomas in different locations. The patient deteriorated into brain death soon after this examination. The pathology of this case was supposed to be "hyperleukocytosis", which is defined as a leukocyte count greater than 100,000/mm3. Severe leukostasis due both to dense leukocytes and lack of mobility of the myeloblast brought about an increase in permeability because of local impairment of nutrition to the walls of the vessels. As a result, the following histological changes occurred: 1) cellular exudation into Virchow-Robin space, 2) the appearance of leukemic nodule, admixtures of leukemic cells and erythrocytes, 3) mechanical compression of the capillaries and venules by the enlarging mass of the leukemic nodules. CT scan showed these characteristics as follows: 1) multiplicity, 2) small-size, 3) cerebral hemisphere, especially in white matter.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Protease-nicked theta-toxin of Clostridium perfringens, a new membrane probe with no cytolytic effect, reveals two classes of cholesterol as toxin-binding sites on sheep erythrocytes.

A nicked theta-toxin (C theta), obtained by limited proteolysis with subtilisin Carlsberg, causes almost no hemolysis while it retains a nearly intact cholesterol binding site below 20 degrees C. Neither electron microscopic evidence for the formation of arc- and ring-shaped structures on the membrane nor toxin-stimulated influx of extracellular Ca2+ are detected in C theta-treated cells below 20 degrees C. Thus, event(s) in the lytic process are responsible for the temperature dependency of hemolysis, which is also supported by the observation that C theta requires higher Arrhenius activation energy for hemolysis than the native toxin. Using C theta as a probe due to its high affinity for membrane cholesterol without causing any obvious membrane changes, we demonstrated the possible existence of high- and low-affinity sites for theta-toxin on sheep erythrocytes. Both binding sites disappear by simultaneous treatment of the cells with sublytic doses of digitonin. Furthermore, C theta binds only to cholesterol among the chloroform/methanol-extractable, lipid components of sheep and human erythrocytes but not to the protein components derived from them. These results strongly suggest that cholesterol is an essential component of the both high- and low-affinity sites, and also imply that the modes of existence of cholesterol in the red cell membrane are heterogeneous.

Animals↗
PubMed1988

Binding site of alpha 2-plasmin inhibitor to plasminogen.

Peptide T-11, a carboxyl terminal tryptic fragment of alpha 2-plasmin inhibitor, inhibits the reversible first step of the reaction between plasmin and alpha 2-plasmin inhibitor. To elucidate which amino-acid residues played a important role in the inhibitory activity of peptide T-11, we prepared the various synthetic derivatives of peptide T-11 and determined the peptide concentration that inhibited the apparent rate constant of the reaction between plasmin and alpha 2-plasmin inhibitor by 50% (IC50). Peptide III, which lacked the residues Gly-1 to Pro-7 of peptide I (peptide T-11), had a strong inhibitory activity, like peptide I (IC50: peptide I, 7 microM; peptide III, 13 microM). The peptides that lacked the Leu-9 and Lys-10 or Lys-26 of peptide III showed much weaker activity, and the loss or amidation of the C-terminal lysine of peptide III also markedly reduced the inhibitory activity. Peptide III competitively inhibited the binding of [14C]tranexamic acid to kringle 1 + 2 + 3 (K1-3) and kringle 4 (K4) in a binding assay performed by the gel-diffusion method. The respective dissociation constants (Kd) of peptide III for K1-3 and K4 were 0.85 microM and 35.2 microM. These data suggest that the amino residue of Lys-10 and the carboxylic acid of Lys-26 in peptide T-11 play crucial roles in the ionic binding of alpha 2-plasmin inhibitor to the tranexamic acid-binding site (lysine-binding site) of plasminogen. Peptide T-11: H-G-D-K-L-F-G-P-D-L-K-L-V-P-P-M-E-E-D-Y-P-Q-F-G-S-P-K-OH.

Amino Acid Sequence↗
PubMed1988

Terminal differentiation and calcification in rabbit chondrocyte cultures grown in centrifuge tubes: regulation by transforming growth factor beta and serum factors.

Rabbit chondrocyte cultures on plastic dishes are capable of depositing a cartilaginous matrix, although the matrix does not calcify unless high levels of phosphate are added to the medium. In the present study, we cultivated a pelleted mass of rabbit growth-plate chondrocytes in the presence of Eagle's minimum essential medium supplemented with 10% fetal bovine serum and 50 micrograms of ascorbic acid per ml in a plastic centrifuge tube. These cells proliferated for several generations and then reorganized into a cartilage-like tissue that calcified without additional phosphate. The deposition of minerals was observed only after synthesis of a short-chain collagen and alkaline phosphatase. Serum factors were required for the increases in alkaline phosphatase and calcium contents. 5-Bromo-2'-deoxyuridine abolished the increases in uronic acid, alkaline phosphatase, and calcium contents. Transforming growth factor beta, at very low concentrations, suppressed the expression of the mineralization-related phenotype by chondrocytes. These results suggest that cartilage-matrix calcification can be controlled by growth factor(s) and that chondrocytes induce the mineralization of extracellular matrix when terminal differentiation is permitted in the absence of an artificial substrate.

Alkaline Phosphatase↗
PubMed1988

Chemotaxis for methamphetamine in Escherichia coli.

Escherichia coli showed the chemotactic response for methamphetamine, a biogenic stimulative amine. The response was qualitatively detected by using a paper disk filter. The quantitative assay showed that E. coli responded to methamphetamine at 10(-5) M or more.

Chemotaxis↗