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Biomedical subjects

K Ishimaru

Publications and source records attributed to K Ishimaru.

At least 37 records · Page 2Linked to original sources
PubMed1996

Identification of novel lymphoid tissues in murine intestinal mucosa where clusters of c-kit+ IL-7R+ Thy1+ lympho-hemopoietic progenitors develop.

We have revealed that about one and a half thousand tiny clusters, filled with one thousand closely packed lymphocytes, can be found throughout the murine small and large intestinal mucosa. They are located in crypt lamina propria (cryptopatches; CP) and can be first detected at 14-17 d after birth. A large fraction of lymphocytes in CP expresses c-kit, IL-7R, Thy1 and a lymphocyte function-associated antigen, LFA-1, whereas most of them remain CD3-, TCR alpha beta-, TCR gamma delta-, sIgM-, and B220-. The population size of IL-2R alpha+, HSA+ and Pgp-1+ subsets is variable (20-50%) and the composition of CD8+, Ly-1+, and CD4+ subsets is smaller but also variable (3-20%). In the small intestine, CP do not contain cells undergoing apoptosis nor cells bearing RAG-1 molecules, but do contain dendritic stromal cells bearing CD11c/CD18 molecules. The frequency of DNA replicating cells in CP is higher than that in Peyer's patches (PP), is lower than that in the thymic cortex and is almost comparable with that in the thymic medulla. The numbers of CP remain the same in aged mice (> 114 wk) but double after estrogen treatment even though the thymi are attenuated sharply in both conditions. Thus, with respect to histogenesis, lymphocyte composition and tissue level of cellular behavior, neither PP, isolated lymphoid follicles, peripheral LNs, nor thymus are identical with CP. Finally, CP are virtually absent in lamina propria of IL-7R-deficient mice that display a profound reduction in thymic and peripheral lymphoid cellularity. By contrast, CP are present in germ-free mice and in athymic (nu/nu), SCID, TCR beta x delta-/-, RAG-2-/-, PP-deficient (aly/aly), stem cell factor (Sl/Sld) and c-kit (W/Wv) mutant mice. Taking all of these results together, CP are the first identification of gut-associated murine lymphoid tissues where the generation of IL-7-dependent lympho-hematopoietic progenitors for T and/or B cell descendants may start to take place at the age of commencement of weaning.

Animals↗
PubMed1996

Large-scale perfusion culture process for suspended mammalian cells that uses a centrifuge with multiple settling zones.

A high-cell-density perfusion culture process, using a novel centrifuge, was developed. The centrifuge has spiral multiple settling zones to separate cells from culture medium. Because of the multiple zones, the separation area can be efficiently increased without enlarging the diameter of the centrifuge. The centrifuge used in this study had a separation capacity of 2600 ml culture medium min -1 at 100 g of the centrifugal force. A new cell separation and withdrawal method was also developed. The cells separated in the centrifuge can be withdrawn easily from the centrifuge with no cell clogging by feeding a liquid carrier such as a perfluorocarbon into the centrifuge and pushing the cells out with the liquid carrier. By this culture process, monoclonal antibodies were produced with mouse-human hybridoma X87X at a cell density of about 8 x 10(6) cells ml -1 for 25 days. This centrifuge culture shows promise as a large-scale perfusion culture process. (Himmelfarb et al. 1969; Feder and Tolbert 1983) usually have the problem of filter clogging, and perfusion culture processes with gravitational cell settling (Tokashiki and Arai 1989) are limited in scale-up because of low separation efficiency. Recently centrifugal separation of cells from culture medium has been used for perfusion culture processes (Hamamoto et al. 1989; Tokashiki et al. 1990; Apelman 1992; Jäger 1992). This process essentially has a high separation efficiency and can avoid further operational problems, such as filter clogging, by the type of filtration. To investigate the scale-up feasibility of the centrifuge culture system, we have developed a new type of centrifuge with four layers of spiral cell-settling zones to increase the separation area, and a novel cell separation and withdrawal method using a perfluorocarbon.

Animals↗
PubMed1995

Two flavone 2'-glucosides from Scutellaria baicalensis.

Two new flavone glucosides, 5,2',6'-trihydroxy-6,7,8-trimethoxyflavone 2'-O-glucoside and 5,2',6'-trihydroxy-6,7-dimethoxyflavone 2'-O-glucoside were isolated from the aqueous methanol extract of the roots of Scutellaria baicalensis. From the extract, seven phenolics, 5,7,2',6'-terahydroxyflavone, 5,7,2',5'-tetrahydroxy-8,6'-dimethoxyflavone, skullcapflavone II, baicalin, baicalin methyl ester, wogonin 7-glucuronide and 3,5,7,2',6'-pentahydroxyflavanone were also isolated.

Flavonoids↗
PubMed1995

Properties of poly(3-hydroxybutyrate) depolymerase from a marine bacterium, Alcaligenes faecalis AE122.

Alcaligenes faecalis AE122 that used poly(3-hydroxybutyrate) (PHB) as a sole source of carbon was newly isolated from a coastal seawater sample. The strain required seawater for growth on PHB as well as in a nutrient broth, in which seawater could be replaced by an appropriate concentration of NaCl. PHB depolymerase was purified to homogeneity from the culture supernatant of A. faecalis AE122 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The enzyme consisted of a monomer subunit with a molecular mass of 95.5 kDa. The N-terminal amino acid sequence was GAWQNNLAGGFNKV. The dimeric and trimeric esters of 3-hydroxybutyrate were the main hydrolysis products of the purified enzyme. The enzyme was most active at pH 9.0 and 55 degrees C and was inhibited by phenylmethylsulfonyl fluoride. Several cations in seawater greatly enhanced the enzyme activity.

Alcaligenes↗
PubMed1995

[Therapeutic effect of a mineralocorticoid in patients with hyponatremia of central origin].

Patients with hyponatremia of central origin were treated with a mineralocorticoid, and the therapeutic effect assessed. The subjects of this study were 14 patients (5 with subarachnoid hemorrhage, 2 with hypertensive intracerebral hemorrhage and 7 with head injury) who developed hyponatremia as a complication during their hospital stay for treatment of their intracranial lesions between March 1993 and April 1994. Hyponatremia of central origin was defined as serum Na+ levels below 135 mEq/l for at least two consecutive days with no other discernible etiology. The mineralocorticoid used was fludrocortisone acetate, and as a rule administration was started the day after the onset of hyponatremia. The mean interval until the onset of hyponatremia was 7.5 days, and the mean minimum serum sodium level was 125.7 mEq/l. The dose of fludrocortisone was 0.3 congruent to 0.6 mg/day, the mean period of administration 5.8 days, and route was via a stomach tube in 3 cases and by mouth in 11 cases. The therapeutic effect was good (improvement within 5 days) in 11 cases and fair (improvement in 5 to 8 days) in 3 cases. None of the patients manifested side effects. All of the patients had lower urinary sodium excretion than before administration, with the mean rate of decrease of 66.9%. Mineralocorticoids, which suppress natriuresis, are safe and effective in the treatment of hyponatremia of central origin. It appears that mineralocorticoid therapy may be aggressively tried in severe cases in which NaCl loading is ineffective.

Adult↗
PubMed1994

Angiogenic activity of the recombinant hst-1 protein.

The hst-1 transforming gene encodes a protein which belongs to the FGF family of growth factors. We showed previously that a human hst-1 protein produced in silkworm cells has in vitro mitogenic activity to vascular endothelial cells. Here we report effective synthesis of an unfused human hst-1 protein in E. coli and a potent in vivo angiogenic activity of this hst-1 protein by two in vivo assays for angiogenesis, chick chorioallantoic membrane assay and rat cornea assay. The NIH3T3 transformant transfected with the hst-1 gene appeared to develop a highly-vascularized tumor on nude mice. These data showed that the hst-1 protein has an angiogenic activity in vivo as well as in vitro.

Animals↗
PubMed1994

Crystallization and preliminary crystallographic data of the alpha-amylase inhibitors, Haim I and Paim I.

Two proteins that act as alpha-amylase inhibitors, Haim I and Paim I, were crystallized and preliminary X-ray diffraction studies on them were carried out. We also sequenced Haim I prepared from Streptomyces griseosporeus YM-25 and confirmed that it is composed of 78 amino acid residues. Crystals of Haim I were grown from ammonium sulfate solution mixed with ethanol by the vapor diffusion technique. The crystals grew as hexagonal bipyramids and diffracted X-rays beyond 2.0 A resolution. They belong to the space group P6(1)22 (or P6(5)22) with unit cell dimensions of a = b = 36.7 A, c = 192.4 A, and contain one molecule per asymmetric unit. Paim I, a protein of 39 amino acid residues produced by Streptomyces corchorusii, was crystallized under similar conditions to Haim I. The crystals diffracted X-rays beyond 2.5 A. They belong to the space group P4(1)2(1)2 (or P4(3)2(1)2) with unit cell dimensions of a = b = 65.4 A, c = 96.1 A, and contain three molecules per asymmetric unit.

Amino Acid Sequence↗
PubMed1994

[A case of benign intracranial hypertension associated with systemic lupus erythematosus (SLE) showing diffuse white matter lesions on MRI].

We describe a 35-year-old woman with benign intracranial hypertension (BIH) secondary to systemic lupus erythematosus (SLE). She had low grade fever and skin eruptions, but neurological examination revealed no abnormal findings. Antinuclear and anti ds-DNA antibodies were positive, and complements were decreased. MRI demonstrated diffuse hyperintense white matter lesions on T2-weighted imaging. Mild bilateral papilledemas developed in the fundi, when her headache was exacerbated. The cerebrospinal fluid (CSF) pressure was 550 mmH2O. Cerebral angiography showed no cerebral sinus thrombosis. She was diagnosed as BIH secondary to SLE. Since RI cisternography revealed remarkably delayed absorption of the CSF, it was speculated that the CSF absorption by arachnoid villi would be probably disturbed in association with some autoimmune mechanisms by SLE. The subsequent rise of intraventricular pressure may result in retrograde transependymal flow of the CSF and the diffuse hyperintense white matter lesions on MRI.

Adult↗
PubMed1993

[Phenylketonuria with adult-onset neurological manifestation].

We report a male patient with phenylketonuria (PKU) who developed multisystem neurological manifestation in his fourth decade. He was born in 1957 when a neonatal mass screening had not been available. His neuropsychological development was entirely normal and he was a good athlete during his high school days. He was in good health until the age of 32, when his vision was blurred. In four months his gait progressively deteriorated to bind him to a wheel chair. On physical examination he had red hair and gray eyes. IQ was 68. Visual field showed concentric narrowing and his visual acuity was 0.2/0.3 (2.0/2.0). The limbs were spastic and weakened. He complained of pain in the extremities. He suffered from pollakisuria. Routine blood tests and CSF findings were normal. He was also found to be normal in peripheral nerve conduction studies and central conduction studies of SEP and VEP. EEG showed diffuse slowing in background activities. T2-weighted MRI of the head revealed widespread high-intensity areas in the deep white matter especially in bilateral occipital lobes. Serum aminogram disclosed the remarkably elevated phenylalanine (Phe) level to 1663 nmol/ml (normal range 50-90) and reduced tyrosine. Urinary secretion of endogenous tetrahydroxy-biopterin (BH4; coenzyme of Phe hydroxylase) remained in a normal range, and oral administration of 100 mg/kg of BH4 failed to normalize the serum Phe level. Despite a strict dietary control (oral intake of Phe less than 0.5 g/day), the serum Phe level remained high around 500 nmol/ml and his neurological deficits still deteriorated.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Effect of calcium antagonists on postischemic protein biosynthesis in gerbil brain.

BACKGROUND AND PURPOSE: Prolonged inhibition of protein synthesis precedes delayed neuronal death in the CA1 sector of the hippocampus after transient cerebral ischemia. Organic calcium antagonists have been recommended for alleviation of ischemic neuronal damage. The present study was undertaken to investigate whether these drugs improve the recovery of protein biosynthesis after interruption of cerebral blood flow. METHODS: Cerebral protein synthesis was measured biochemically and autoradiographically in gerbils submitted to 5 minutes of bilateral occlusion of the common carotid arteries followed by 2 hours or 2 days of recirculation. Flunarizine (25 mg/kg) or nimodipine (1.5 mg/kg) were applied intraperitoneally shortly after ischemia. RESULTS: Treatment with either calcium antagonist did not markedly influence postischemic recovery of protein synthesis in the resistant regions of the brain and did not prevent the persisting inhibition in the vulnerable stratum pyramidale of the CA1 sector of the hippocampus. CONCLUSIONS: The postischemic application of the organic calcium antagonists nimodipine and flunarizine does not promote postischemic recovery of protein synthesis. The beneficial effects of these drugs must, therefore, be based on other mechanisms.

Amino Acids↗
PubMed1992

Enzymatic synthesis of 2-chloro-4-nitrophenyl 4,6-O-3-ketobutylidene beta-maltopentaoside, a substrate for alpha-amylase.

A transglycosylation reaction with 2-chloro-4-nitrophenyl beta-maltoside as an acceptor was done with 4,6-O-3-ketobutylidene maltopentaose and Bacillus macerans cyclodextrin glucanotransferase in an aqueous solution containing 50% n-propanol, and there were two main transglycosylation products. They were identified as 2-chloro-4-nitrophenyl 4,6-O-3-ketobutylidene beta-maltopentaoside and 2-chloro-4-nitrophenyl 4,6-O-3-ketobutylidene beta-maltohexaoside, and their yields were 30% and 21% respectively on the basis of the decrease of 4,6-O-3-ketobutylidene maltopentaose. For the production of 2-chloro-4-nitrophenyl 4,6-O-3-ketobutylidene beta-maltopentaoside at high substrates concentrations, the addition of n-propanol in this reaction not only increased the solubility of 2-chloro-4-nitrophenyl beta-maltoside sufficiently but also suppressed side reactions.

1-Propanol↗
PubMed1991

Two cDNAs encoding novel human FGF receptor.

Two types of cDNAs encoding novel human FGF receptors were isolated. These two cDNAs were found to be closely related to the oncogene bek. Products from these genes were membrane-bound when their cDNAs were transiently expressed in COS cells, whereas products from the regions coding extracellular domains were free of membrane attachment and found in the culture medium.

Amino Acid Sequence↗
PubMed1991

Determination of alpha-amylase using a new blocked substrate (3-ketobutylidene beta-2-chloro-4-nitrophenyl-maltopentaoside).

A new substrate, 3-ketobutylidene beta-2-chloro-4-nitrophenylmaltopentaoside (3KB-CNPG5), was used for the determination of alpha-amylase (EC 3.2.1.1) in serum and urine. Under this alpha-amylase assay condition, 3KB-CNPG5 is resistant to glucoamylase and alpha-glucosidase, which are auxiliary enzymes, because the 4- and 6-positions of the non-reducing-end glucose residue are modified by the 3-ketobutylidene group. The assay using 3KB-CNPG5 for alpha-amylase activity is a highly sensitive method that uses 2-chloro-4-nitrophenol (CNP) as an aglycone, and is a stable method for determination of alpha-amylase activity in biological fluids.

Chromatography, High Pressure Liquid↗
PubMed1991

A monoclonal antibody to scopolamine and its use for competitive enzyme-linked immunosorbent assay.

A hybridoma clone producing a monoclonal antibody (SC78.H81) against scopolamine was established. The monoclonal antibody was an IgG1 (k) antibody with high affinity (1.6 x 10(9) M-1 for methylscopolamine). The monoclonal antibody was cross-reactive with methylscopolamine and butylscopolamine, and showed weak cross-reactivity with 6 beta- and 7 beta-hydroxyhyoscyamine. The cross-reaction with L-hyoscyamine, atropine, scopine and DL-tropic acid was very weak. A competitive enzyme-linked immunosorbent assay using SC78.H81 was established to quantify scopolamine. The sensitivity of the assay allowed detection of 20 pg assay-1 (0.2 ng ml-1) of scopolamine. The assay was applied to the estimation of scopolamine content in hairy root cultures of a Duboisia hybrid.

Antibodies, Monoclonal↗
PubMed1990

High density culture of hybridoma cells using a perfusion culture vessel with an external centrifuge.

The influence of centrifugal force on the growth of cells was examined by exposing the cells of the mouse-human hybridoma X87 line to centrifugal force (100-500 G) for ten minutes twice a day and comparing the static culture with that of unexposed cells. In this experiment, both cell proliferation and specific antibody productivity were independent of the centrifugal effect, and gave the same results as in the case of no exposure to centrifugal force. High density cultivation of the mouse-human hybridoma X87 line was obtained by a perfusion system where the cells were separated from the culture medium by continuous centrifugation. In the serum-free culture, the maximum viable cell density exceeded 10(7) cells/ml, and monoclonal antibody was stably produced for 37 days. The results in this culture were equivalent to those obtained by intermittent centrifugal cell separation from the culture medium, and separation by gravitational settlement.

Animals↗
PubMed1989

[A comparative study between cefodizime (CDZM) and cefotaxime (CTX) in respiratory tract infections].

The clinical efficacy and safety of Cefodizime (CDZM), a new cephem antibiotic, was objectively compared with that of Cefotaxime (CTX) in patients with respiratory infections under a well-controlled comparative study. Patients were administered CDZM or CTX by drip infusion b.i.d. for 14 days in principle at a daily dose of two grams. The parameters assessed were clinical efficacy, safety and clinical usefulness. The following results were obtained: 1. On the basis of committee judgement the clinical efficacy rate was 78.1% (125/160) for the CDZM group, 82.7% (124/150) for the CTX group, and no significant difference was observed between the two drug groups. On the other hand, on the basis of judgement by physicians in charge, the clinical efficacy rate was 83.1% (133/160) for the CDZM group, 83.9% (125/149) for the CTX group, and no significant difference was observed between the two groups. 2. The corresponding figures for patients with pneumonia and pulmonary suppuration were 82.4% (70/85) for the CDZM group, 79.7% (59/74) for the CTX group and no significant difference was observed according to the committee judgement. The judgement by physicians in charge also revealed 83.5% (71/85) for the CDZM group and 82.2% (60/73) for the CTX group. No significant difference was noted between the two groups. While, the committee judgement for the clinical efficacy in patients with chronic respiratory tract infections showed 73.3% (55/75) for the CDZM group, 85.5% (65/76) for the CTX group, and no significant difference was observed between the two drug groups. The corresponding figures were 82.7% (62/75) for the CDZM group, 85.5% (65/76) for the CTX group, and no significant difference was observed between the two drug groups on the judgement by physicians in charge. Furthermore, the clinical efficacy of both drugs on chronic respiratory tract infections was assessed according to "Criteria for Evaluation of Clinical Efficacy of Chemotherapeutics on Chronic Respiratory Tract Infection". It was 76.8% (53/69) for the CDZM group, 76.3% (58/76) for the CTX group, and no significant difference was observed between the two groups. 3. The bacteriological eradication rate of causative pathogens was 92.4% out of 66 patients treated with CDZM and 95.5% out of 67 patients treated with CTX in whom judgement was possible. No significant difference was observed between the two drug groups. 4. The adverse reactions occurred in 4 (2.2%) patients for the CDZM group and 8 (4.5%) patients for the CTX group respectively, with no significant inter-group difference in frequency of these reactions for all cases.(ABSTRACT TRUNCATED AT 400 WORDS)

Anti-Bacterial Agents↗