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N Katagiri

Publications and source records attributed to N Katagiri.

At least 19 recordsLinked to original sources
PubMed2002

A novel beta-N-acetylglucosaminidase of Clostridium paraputrificum M-21 with high activity on chitobiose.

A beta- N-acetylglucosaminidase gene ( nag3A) from Clostridium paraputrificum M-21 was cloned in Escherichia coli. The nag3A gene consists of an open reading frame of 1,239-bp, encoding 413 amino acids with a deduced molecular weight of 45,531 Da. Nag3A is a single domain enzyme containing a family 3 glycoside hydrolase catalytic domain. Nag3A was purified from recombinant E. coli and characterized. The enzyme hydrolyzed chitooligomers such as di- N-acetylchitobiose, tri- N-acetylchitotriose, tetra- N-acetylchitotetraose, penta- N-acetylchitopentaose, hexa- N-acetylchitohexaose, ball-milled chitin, and synthetic substrates such as 4-methylumbelliferyl N-acetyl beta- D-glucosaminide [4-MU-(GlcNAc)], but had no activity at all against p-nitrophenyl-beta- D-glucoside, p-nitrophenyl-beta- D-xyloside, or p-nitrophenyl-beta- D-galactosamine. The enzyme was optimally active at 50 degrees C and pH 7.0, and the apparent K(m) and V(max) values for 4-MU-(GlcNAc) were 7.9 micro M and 21.8 micro mol min(-1) mg protein(-1), respectively. SDS-PAGE, zymogram, and immunological analyses suggested that this enzyme is induced by ball-milled chitin.

Acetylglucosaminidase↗
PubMed2001

Demonstration of a rhodopsin-retinochrome system in the stalk eye of a marine gastropod, Onchidium, by immunohistochemistry.

The stalk eye of Onchidium sp. (Gastropoda, Mollusca) is the principal photoreceptor in a multiple photoreceptive system that consists of the stalk and dorsal eyes, dermal photoreceptor cells, and photosensitive neurons. To examine the localization of photopigments, the stalk eyes were immunostained with specific antibodies to rhodopsin, retinochrome, and retinal-binding protein (RALBP), which had been generated against squid retinal proteins. The retina of the stalk eye was divided into villous, pigmented, somatic, and neural layers. It was comprised mainly of two types of visual and pigmented supportive cells. The type 1 visual (VC1) cell was characterized by well-developed microvilli on its apical protrusion and photic vesicles in the cytoplasm. The photic vesicles were specifically blackened by prolonged osmification. The type 2 visual (VC2) cell had less numerous, shorter microvilli on its concave apical surface and lacked photic vesicles. The anti-squid rhodopsin antiserum was localized specifically to the villous layer that corresponded to the VC1 microvilli. With the anti-retinochrome peptide antibody, the somatic layer showed specific but patchy, positive staining that corresponded to the cytoplasm of the VC1 cells. Because the photic vesicles are known to contain retinochrome, these results indicate that this retinochrome is localized in the VC1 cytoplasm. Anti-RALBP antibody stained the supranuclear cytoplasm to the distal cytoplasm of VC1 cells. This is the first demonstration of the localization of RALBP in the Gastropoda Onchidium stalk eye. In squid retina that were immunostained as positive controls, the anti-rhodopsin antibody stained rhabdomeric microvilli, the anti-retinochrome antibody stained the inner segment and the basal region of the outer segment, and the anti-RALBP antibody stained the outer and inner segments, respectively. These results suggest that the rhodopsin-retinochrome system that has been established in cephalopod eyes is present in the Onchidium stalk eye.

Animals↗
PubMed2001

Redistribution in I-123 N-isopropyl-p iodoamphetamine single-photon emission computed tomography in cerebrovascular disease and the effects of rehabilitation.

We performed N-isopropyl-p (I-123) iodoamphetamine (IMP) single-photon emission computed tomography (SPECT) on 28 patients with severe cerebrovascular disease before rehabilitation, and compared the degree of redistribution and the assessment of activities of daily living (ADL). We calculated a redistribution (RD) ratio in the central and peripheral parts of the lesions: RD ratio (c) and RD ratio (p). We classified the patients into four groups based on the degree of redistribution: complete: both RD ratio (c) and (p) > or = 75; peripheral: RD ratio (c) < 75, RD ratio (p) > or = 75; incomplete: both RD ratio (c) and (p) < 75 and at least one of RD ratio (c) or (p) > or = 25; no redistribution: both RD ratio (c) and (p) < 25. We assessed the ADL using the modified Barthel index (BI). deltaBI was defined as BI after rehabilitation-BI before rehabilitation (BIpost-BIpre). The deltaBI of the four groups were as follows: complete-redistribution group (40.8 +/- 22.8), peripheral-redistribution group (40.0 +/- 15.8), incomplete-redistribution group (27.2 +/- 22.6), no-redistribution group (8.8 +/- 12.3). The deltaBI of the complete and peripheral redistribution groups were significantly higher than that of the no-redistribution group. However, deltaBI was almost the same in the complete- and peripheral-redistribution groups. This suggests that the effect of rehabilitation might be closely related to the viability of the peripheral part of the lesion.

Activities of Daily Living↗
PubMed2000

Preprimed artificial lung for emergency use.

We investigated the possibility of preprimed storage of an artificial lung (AL), aiming at facilitating its emergency use. Test ALs, consisting of a special microporous hollow fiber membrane made of polyolefin in which direct blood-gas contact was completely eliminated, were preprimed with saline solution, sterilized by gamma-ray irradiation, and evaluated after 1-3 months of storage at room temperature. A small amount of bubble was noted in the priming solution after storage in some ALs, which most likely originated from the air dissolved in the priming solution or persisted in the liquid compartment at priming. Although the preprimed solution contained several polyolefin-breakdown products due to irradiation, including ethyl alcohol, n- and t-butyl alcohol, acetone, and carbon dioxide, the levels of these substances were at concentrations known to be not toxic. Endotoxin concentration was negligible. In SEM observation, no perceptible microstructural change was observed in the hollow fibers after preprimed storage. Maximum tensile stress and ultimate elongation of the hollow fiber in the test ALs were reduced by approximately 20% and 3%, respectively, from those of the control AL. The influence of preprimed storage on gas-exchange function was examined in a venoarterial bypass animal study using a goat. Oxygen transfer function was well preserved whereas carbon dioxide removal function was slightly lowered according to the storage term in the stored ALs compared with those of a nonpreprimed control AL. On the basis of these results, we conclude that preprimed storage of the AL with gamma-ray sterilization is basically feasible and realistic.

1-Butanol↗
PubMed1999

Early postmenopausal bone loss is prevented by estrogen and partially by 1alpha-OH-vitamin D3: therapeutic effects of estrogen and/or 1alpha-OH-vitamin D3.

A total of 79 Japanese women who were within 5 years of menopause were randomly assigned 1alpha-hydroxyvitamin D3 [1alpha(OH)D3] 1.0 microg/day, conjugated estrogens 0.625 mg/day, a combination of both, or control (no treatment). Lumbar spine and proximal femur bone mineral density (BMD) and biochemical indices were monitored over 2 years. In the 1alpha(OH)D3-treated group, there was a nonsignificant decrease in lumbar spine BMD compared with controls, and no significant loss in the femoral neck compared with controls. In the estrogen-treated group, there was a nonsignificant increase in spine BMD (+2.17% in the first year and +1.71% in the second year), and no loss in femoral neck BMD. The combination of conjugated estrogens +1alpha(OH)D3 was more effective in increasing BMD in the spine (+3. 68% in the first year and +3.63% in the second year) and femur (+2. 56% in the first year and +4.44% in the second year) BMD. There was a significant difference in lumbar spine BMD in both the first and second years between the combination-treated group and the 1alpha(OH)D3-treated and control groups (P < 0.01). Serum osteocalcin (OC) significantly decreased in the combination-treated group (-23.8% in the first year) and the estrogen-treated group (-37. 6% and -41.2% at 6 and 18 months, respectively), and serum alkaline phosphatase (Alp) decreased significantly in the first year in the combination-treated (-31.5%), estrogen-treated (-27.3%), and 1alpha(OH)D3-treated (-7.9%) groups, whereas serum OC increased (+45. 4% in the first year) in women without treatment. The results of this study indicate that early postmenopausal bone loss in the femoral neck is prevented by conjugated estrogens, 1alpha(OH)D3, or both, whereas bone loss in the spine is not prevented by 1alpha(OH)D3. Estrogen proves effective in preventing early postmenopausal bone loss by markedly inhibiting bone turnover. Moreover, a synergistic bone-sparing effect can be expected when estrogen is administered concomitantly with 1alpha(OH)D3 rather than when used alone.

Adult↗
PubMed1999

Synthesis of carbocyclic nucleosides bearing a cyclopropane ring.

A carbocyclic cyclopropane fused nucleoside, 9-(c-4-hydroxymethylbicyclo[3.1.0]hex-r-2-yl)-9H-adenine, has been efficiently synthesized from 2-azabicyclo-[2.2.1]hex-5-en-3-one (ABH) in 6 steps, namely cyclopropanation, -reductive amide cleavage (RAC) reaction and adenine ring construction.

Antiviral Agents↗
PubMed1999

Low-dose GnRH agonist therapy for the management of endometriosis.

OBJECTIVE: In order to examine whether treatment with a GnRH agonist alone can maintain estrogen levels within the "estrogen window" that inhibits endometriosis without influencing bone-mineral density, we studied the effects of GnRH agonist therapy and changes in bone-mineral density. METHODS: Buserelin acetate nasal spray was administered 3 times a day for 8 weeks (daily dose, 900 micrograms) to 21 women with endometriosis. The drug was then given twice a day for 16 weeks (daily dose, 600 micrograms). The total duration of treatment was 24 weeks. The bone-mineral density of the lumbar vertebrae was measured by dual-energy X-ray absorptiometry before treatment (baseline), at the end of treatment, and 24 weeks after the end of treatment. RESULTS: The bone-mineral density of the lumbar vertebrae at the end of treatment was 2.44% +/- 0.46% (mean +/- standard error) lower than the baseline value. The value at 24 weeks after the end of treatment was 1.10% +/- 0.64% lower than the baseline value. More than 80% of the patients had serum-estradiol levels of 45 pg/ml or less. During treatment, more than 90% of the patients had serum-estradiol levels of 60 pg/ml or less. Genital bleeding was inhibited in 90% of the patients. After 8 weeks of treatment, the clinical symptoms improved in 75% of the patients; such improvement persisted for the duration of the treatment. CONCLUSION: Decreasing the dose of GnRH agonist during treatment can minimize the loss of bone-mineral density without lessening the beneficial effects on endometriosis. This technique might be useful in the management of endometriosis.

Abdominal Pain↗
PubMed1998

Reduction of glycogen in eggs of the silkworm, Bombyx mori, by use of a trehalase inhibitor, trehazolin, and diapause induction in glycogen-reduced eggs.

A new trehalase inhibitor, trehazolin, caused a potent inhibition of ovary trehalase in the silkworm, Bombyx mori. A single injection of trehazolin into pupae (40&mgr;g/animal) did not interfere with the accumulation of proteins and lipids, but markedly reduced glycogen content in eggs accompanied by a remarkable increase in hemolymph trehalose levels. The most potent effect of trehazolin was expressed in eggs that developed at the mid-stage of pupal-adult development. In these eggs glycogen content was reduced to a trace level, less than 3% of that of the control. The reduced glycogen content was almost restored to the control level by injection of glucose but not by trehalose. Trehazolin treatment influenced oviposition and larval hatching, whereas embryogenesis went on normally in glycogen-reduced eggs. Injection of synthetic diapause hormone into non-diapause type hosts induced an incidence of 45% diapause in the eggs and increased their glycogen content. Surprisingly, injection of trehazolin never affected diapause induction by the hormone, despite considerably reduced glycogen content in these eggs. Thus, our findings provide a new method for production of eggs containing various amounts of glycogen, and a novel system for analyzing diapause-associated metabolism besides the well-known glycogen-sorbitol metabolism.

Journal Article↗
PubMed1998

Case of acrania associated with congenital medulloblastoma.

A case of acrania associated with medulloblastoma, agenesis of the cerebellum, and nasoshizis, is reported. The diagnosis of acrania was made at the 20th gestational week by sonographic examination. To our knowledge, this is the first report of fetal acrania associated with congenital brain tumor.

Abortion, Induced↗
PubMed1997

A simple method for purification of adult pig pancreatic endocrine cells.

Adult pig pancreatic endocrine cells were harvested by autodigestion without added enzymes. The isolated, crude cells were purified by mono-poly resolving medium (MPRM). The purity of the harvested cells was determined by dithizone staining and the number of pancreatic endocrine cells was counted. A large number of the cells were stained red with dithizone and showed a high viability and a good insulin secretory response to glucose stimulation. The average number of cells purified by MPRM was 3.40 +/- 1.32 x 10(5) cells/g pancreas and the number of dithizone-stained cells was 2.81 +/- 1.09 x 10(5) cells/g pancreas. The insulin secretion from the pancreatic endocrine cells was maintained throughout a 40-day observation period and high glucose stimulation induced an increase in insulin secretion from the cultured cells. In the cells purified by MPRM, light and electron microscopic studies showed the cells to be typical pancreatic endocrine cells. The present purification method using MPRM allowed us quickly to obtain a large amount of adult pig pancreatic endocrine cells from the unpurified preparations. It is thought to be useful for transplantation and biochemical or biological studies of adult pig pancreatic endocrine cells.

Animals↗
PubMed1995

Correlation of brightening with cumulative enzyme activity related to lignin biodegradation during biobleaching of kraft pulp by white rot fungi in the solid-state fermentation system.

Biobleaching of hardwood unbleached kraft pulp (UKP) by Phanerochaete chrysosporium and Trametes versicolor was studied in the solid-state fermentation system with different culture media. In this fermentation system with low-nitrogen and high-carbon culture medium, pulp brightness increased by 15 and 30 points after 5 days of treatment with T. versicolor and P. chrysosporium, respectively, and the pulp kappa number decreased with increasing brightness. A comparison of manganese peroxidase (MnP), lignin peroxidase (LiP), and laccase activities assayed by using fungus-treated pulp and the filtrate after homogenizing the fungus-treated pulp in buffer solution indicated that enzymes secreted from fungi were adsorbed onto the UKP and that assays of these enzyme activities should be carried out with the treated pulp. Time course studies of brightness increase and MnP activity during treatment with P. chrysosporium suggested that it was difficult to correlate them on the basis of data obtained on a certain day of incubation, because the MnP activity fluctuated dramatically during the treatment time. When brightness increase and cumulative MnP, LiP, and laccase activities were determined, a linear relationship between brightness increase and cumulative MnP activity was found in the solid-state fermentation system with both P. chrysosporium and T. versicolor. This result suggests that MnP is involved in brightening of UKP by white rot fungi.

Basidiomycota↗
PubMed1995

Synthesis of carbocyclic nucleoside precursors from bicyclo[2.2.1]hept-5-enes using a novel reductive C-C bond cleavage reaction.

Dimethyl c-4-aminomethylcyclo-pent-2-en-r-1-ylmalonate, an precursor of carbocyclic homo-nucleosides, has been synthesized from the bicyclo-[2.2.1]helpt-5-ene derivative prepared by the Diels-Alder reaction of cyclopentadiene with dimethyl trifluoroacetylaminomethylenemalonate, which is a new dienophile. The synthetic method involves a novel C-C bond cleavage reaction by sodium borohydride.

Borohydrides↗
PubMed1994

Effect of gonadotropin-releasing hormone agonist on the bone mineral density of patients with endometriosis.

OBJECTIVE: To examine changes in bone mineral density (BMD) of patients treated with GnRH agonist (GnRH-a) by dual-energy X-ray absorptiometry and to understand factors related to bone loss. DESIGN: Prospective controlled trial examining BMD during and after GnRH-a therapy every 24 weeks for 18 months in patients with endometriosis compared with nontreated controls. SETTING: Outpatients clinic at a university hospital and its affiliated outpatient clinic. PATIENTS: Twenty-two patients with endometriosis as GnRH-a-treated group, 12 healthy women with normal menstrual cycle, and 7 patients with mild endometriosis as control group. INTERVENTIONS: Patients were treated with a GnRH-a (buserelin acetate) at 900 micrograms/d by nasal spray for 24 weeks. RESULTS: The significance of differences in change-rates at all measured points in both groups was assessed by analysis of variance. The interaction between treatment and period was significant, and only week 24 of the GnRH-a-treated group was significantly lower compared with baseline. The reduction rate of BMD was high in patients 33 years of age or younger compared with those who were 34 years of age or older. According to a multiple-regression model, the most important factor related to bone loss was the post-treatment serum levels of E2. CONCLUSION: At the end of treatment, BMD was significantly lower than that of the control group, and the reduction rate was 3.4%. A factor related to bone loss was degree of ovarian suppression.

Adult↗
PubMed1994

Distribution patterns of Gd-DTPA-enhanced magnetic resonance imaging after intravenous tissue plasminogen activator therapy for acute myocardial infarction.

In patients who received thrombolytic therapy for acute myocardial infarction (AMI), we observed 3 distinct patterns in gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA)-enhanced magnetic resonance (MR) imaging. To clarify the significance of these distribution patterns of Gd-DTPA, 20 consecutive patients underwent Gd-DTPA-enhanced MR imaging 7-10 days after AMI. All of the patients received intravenous recombinant tissue plasminogen activator (IVTPA) within 6 h of onset. Echocardiograms were obtained prior to and serially over 10 days, and interpreted for regional wall motion. Coronary angiograms were obtained the day before discharge. None of the 6 patients with a closed infarct-related artery, and 9 of the 14 patients with an open artery, demonstrated subendocardial enhancement (p < 0.05). All of these latter 9 patients demonstrated a significant improvement in wall motion between days 1 and 10 after AMI. In contrast, only 1 of the 7 patients with transmural enhancement and none of the 4 patients with non-homogeneous enhancement demonstrated improvement of wall motion on day 10 (p < 0.05). We concluded that subendocardial enhancement was a fair prognostic sign for restoration of regional cardiac function in patients who received IVTPA during AMI.

Aged↗
PubMed1993

[Synthetic studies on highly modified nucleosides directed towards creation of anti-HIV agents].

Recent studies on the synthesis of highly modified nucleosides, especially carbocyclic nucleosides, aiming at creating anti-HIV agents have been reviewed. The review includes new methods for the synthesis of carbocyclic C-nucleosides and carbocyclic N-nucleosides including carbocyclic oxetanocin and its analogues developed in our laboratory. Among the carbocyclic nucleosides synthesized, 9-(c-4,t-5-bishydroxymethylcyclopent-2-en-r-1-yl)-9H-adenine (BCA) showed significant anti-HIV activity.

Drug Design↗