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Biomedical subjects

K Kajiwara

Publications and source records attributed to K Kajiwara.

At least 127 records · Page 7Linked to original sources
PubMed1991

Major histocompatibility complex expression in brain of rats with graft-versus-host disease.

In a healthy state, the central nervous system (CNS) is believed to be an immunologically privileged site, which does not participate in the immune reactions of the rest of the body, and in which identifiable components of the immune system are rare or non-existent. In this study, an immunohistochemical examination of the CNS of F1 hybrid rats following induction of graft-versus-host disease (GVHD) was carried out to determine whether specific immune reactions in the normal CNS could occur during a systemic immune reaction. The results revealed extensive parenchymal and vascular expression of class I and II major histocompatibility complex (MHC) encoded cell surface molecules. The strongest expressors of class I and II molecules were endothelial cells and parenchymal cells, respectively, the latter being apparently activated microglia, in the cerebrum and cerebellum of rats with GVHD. In addition, occasional scattered lymphocytes were detected in the CNS of GVHD rats without blood-brain barrier disruption. Thus, evidence was obtained for the presence of immune responses such as MHC antigen expression and lymphocyte infiltration in the CNS during a strong systemic immune response such as GVHD, microglia and endothelial cells apparently playing an important role.

Animals↗
PubMed1991

Purification and characterization of Streptomyces griseus metalloendopeptidases I and II.

Two metalloendopeptidases, designated as Streptomyces griseus metalloendopeptidases I and II (SGMPI and SGMPII), were isolated from a commercial Pronase P by a method including affinity chromatography on carbobenzoxy-L-alaninyl-triethylenetetraminyl-Sepharose (Z-Ala-T-Sepharose). The two enzymes differed from each other in behavior on ion-exchange chromatography but showed the same amino-terminal sequence at least up to the 20th residue. Their molecular weights were both estimated to be 37,000 by SDS-polyacrylamide gel electrophoresis. Elemental and amino acid composition analyses indicated that both of them contained about 1 g atom of zinc and one cystine residue per mol of protein. Cleavage specificities of the two enzymes toward synthetic peptide-substrates were very similar to those observed with thermolysin. EDTA, o-phenanthroline, and phosphoramidon strongly inhibited these enzymes, while typical serine-protease inhibitors and cysteine-protease inhibitors had no effect. The findings clearly indicate that SGMPI and SGMPII can be classified into the family of zinc-endopeptidases. It was unexpectedly found, however, that these metalloendopeptidases were strongly inhibited by protein serine-protease inhibitors produced by Streptomycetes, such as Streptomyces subtilisin inhibitor (SSI), alkaline protease inhibitor-2c' (API-2c'), and plasminostreptin (PS).

Amino Acids↗
PubMed1991

Application of bimane-peptide substrates to spectrofluorometric assays of metalloendopeptidases.

A spectrofluorometric method for sensitive determination of metalloendopeptidase activity has been developed by using a bimane-peptide containing a tryptophan residue, i.e. 1,7-dioxo-2,5,6-trimethyl-1H,7H-pyrazolo[1,2-alpha]pyrazol-3-yl-methyl- thiomethylcarbonyl-phenylalanyl-tryptophanyl-leucine (Bim-SCH2CO-Phe-Trp-Leu-OH). Such an "intramolecularly quenched" substrate was originally designed for a sensitive assay of angiotensin I converting enzyme (ACE) [Sato, E. et al. (1989) Chem. Pharm. Bull. 37, 145-147]. All the typical metalloendopeptidases tested, such as thermolysin, Pseudomonas aeruginosa (Ps.) elastase, Streptomyces griseus metalloendopeptidases I and II (SGMPI and SGMPII), and alkinonase A, a metalloendopeptidase from Streptomyces violaceorectus, cleaved this substrate strictly at a Phe-Trp bond, leading to a marked increase in fluorescence. Kinetic parameters of the enzymatic hydrolyses of five kinds of analogous bimane substrates were compared to examine how the nature of neighboring amino acid residues on either side of the cleavable bond affects the catalytic efficiency of each of the metalloendopeptidases. Bim-SCH2CO-Phe-Trp-Leu-OH was most efficiently hydrolyzed by all of these enzymes. The use of this substrate made it possible to determine minute amounts of metalloendopeptidases, especially those originating from Streptomycetes (for example, as little as 10 fmol of SGMPII).

Amino Acid Sequence↗
PubMed1991

Interactions of Streptomyces serine-protease inhibitors with Streptomyces griseus metalloendopeptidase II.

Streptomyces griseus metalloendopeptidase II (SGMPII) was shown to form tight complexes with several Streptomyces protein inhibitors which had been believed to be specific to serine proteases, such as Streptomyces subtilisin inhibitor (SSI), plasminostreptin (PS), and alkaline protease inhibitor-2c' (API-2c'), as well as with Streptomyces metalloprotease inhibitor (SMPI). The dissociation constants of complexes between SGMPII and these inhibitors were successfully determined by using a novel fluorogenic bimane-peptide substrate. The values ranged from nM to pM. The results of studies by gel chromatographic and enzymatic analyses indicated that SGMPII is liberated from the complex with SSI by the addition of subtilisin BPN'. SGMPII and subtilisin BPN' proved, therefore, to interact with SSI in a competitive manner, despite the difference in the chemical nature of their active sites.

Base Sequence↗
PubMed1991

Mild hypothermia ameliorates ubiquitin synthesis and prevents delayed neuronal death in the gerbil hippocampus.

BACKGROUND AND PURPOSE: The purpose of the present study is to determine the effect of mild hypothermia on the synthesis of ubiquitin, an important protein for maintenance of cell viability, in the hippocampal neurons following transient cerebral ischemia. METHODS: Transient ischemia was induced by occluding both common carotid arteries for 5 minutes. In experiment 1, the animals were divided into four groups according to the rectal and scalp temperatures during ischemia: the normothermia group and the graded hypothermia A, B, and C groups (n = 9 per group). CA1 neuronal density was assessed at 7 days after ischemia. In experiment 2, the animals were divided into two groups designated the normothermia and the hypothermia groups (n = 6 per group). The presence of ubiquitin was examined by immunohistochemistry at 6, 24, and 48 hours after transient ischemia in various regions of the hippocampus. RESULTS: In experiment 1, the mean +/- SEM neuronal density per millimeter was 12 +/- 1 in the normothermia group and 126 +/- 25, 225 +/- 10, and 214 +/- 9 in hypothermia groups A, B, and C, respectively. Mild hypothermia in groups B and C, in which the brain temperature was below 33 degrees C, ameliorated markedly the extent of ischemic neuronal damage in the CA1 sector (p less than 0.01). In experiment 2, ubiquitin immunoreactivity had disappeared in all regions of the hippocampus at 6 hours after ischemia and showed no subsequent recovery in the CA1 pyramidal neurons under normothermic conditions. Under hypothermic conditions, however, it had recovered significantly in the CA1 pyramidal neurons at 24 and 48 hours after ischemia (p less than 0.01). CONCLUSIONS: We conclude that mild hypothermia, in which the brain temperature is below 33 degrees C, markedly improves the ischemic delayed neuronal damage in the CA1 sector, and that increased ubiquitin synthesis and protein ubiquitination could be one essential part of the protective mechanism afforded by mild hypothermia against delayed neuronal death.

Animals↗
PubMed1991

An artificial endocrine pancreas--problems awaiting solution for long-term clinical applications of a glucose sensor.

The artificial endocrine pancreas is a feedback controlled system regulating insulin delivery on a minute-by-minute basis according to measured blood glucose levels. The bedside-type artificial endocrine pancreas has been proven to be useful not only as a therapeutic tool for diabetic patients but also as an elegant research tool for investigating the pathophysiology of the disease. Recently, a wearable-type, closed-loop system has been developed, of which the breakthrough was the establishment of a needle-type glucose sensor. However, for the long-term clinical use of needle-type glucose sensors, several obstacles remain to be solved, such as oxygen dependency, biocompatibility of the membrane, etc. The most promising method for the non-invasive determination of blood glucose is infrared spectroscopy. The trend in the development of a closed-loop glycemic control system which enables perfectly physiological glycemic regulation on a long-term basis is directed to an implantable device. Much research is being conducted to realize such devices.

Alginates↗
PubMed1991

[A study on hepatic arterial infusion for metastatic liver tumor].

This study was designed to evaluate whether hepatic arterial infusion is effective in terms of response rate and survival time of patients with unresectable liver metastasis from colorectal and gastric cancer. In 19 patients with liver metastasis from colorectal cancer, one patient had a CR, 3 had a PR or MR and the remainder showed NC or PD, with an overall response rate of 16.7%. The response rate was higher in men than in women as well as in patients with metachronous liver metastasis. The dose schedules showed no effectiveness in patients with histologically well-differentiated adenocarcinoma. However, there was a statistical difference in survival time according to the response. The overall response rate in 7 patients with liver metastasis from gastric cancer was 42.9% with one patient achieving CR, 2 patients PR and the others PD. As a result, hepatic arterial infusion of antitumor regimen was an effective method for inoperable metastatic liver cancer.

Adenocarcinoma↗
PubMed1991

[Quantification of wallerian degeneration of the pyramidal tract in the capsular region by magnetic resonance imaging].

Using magnetic resonance imaging, we studied 23 patients with motor deficit associated with cerebrovascular disease of the internal capsule. According to the severity of the motor deficits, 23 patients were divided into three groups (severe group...9, moderately severe group...8, mild group...6). A coronal T2-weighted image was obtained along a straight line between the front edge of the medulla and the deepest point of the interpeduncular cistern in a midsagittal T1-weighted image. It was revealed that wallerian degeneration extended continuously from part of the internal capsule down to the pons or medulla or the decussation in all patients. The area of wallerian degeneration in the pons and the area of half the pons were calculated from the coronal T2-weighted image. Moreover, the wallerian index was calculated as: (area of wallerian degeneration in pons divided by area of half the pons) X 100. Values of the wallerian index +/- SD were 26.4 +/- 5.1 in the severe group, 19.2 +/- 5.6 in the moderately severe group, and 10.0 +/- 5.4 in the mild group. There were significant differences among the three groups. We concluded that the area of wallerian degeneration was related to the severity of motor deficits.

Adult↗
PubMed1990

Dynamic mechanism of the self-assembly process of tobacco mosaic virus protein studied by rapid temperature-jump small-angle X-ray scattering using synchrotron radiation.

The self-assembly process of tobacco mosaic virus protein (TMVP) was observed by rapid temperature-jump time-resolved solution X-ray small-angle scattering using synchrotron radiation. The temperature-jump device used for the X-ray measurements is rapid enough to cope with even the fastest-assembling process of TMVP, and accumulates data of reasonable signal-to-noise ratios with a minimum total counting time of 7.5 seconds. The measurements suggested that the 20 S disk of TMVP polymerized to stacked disks (short rods). The time to complete stacking varied from approximately 25 seconds to approximately 1200 seconds, depending on the solution condition and magnitude of the temperature gap. Higher protein concentration, ionic strength and temperature favoured faster association. The results were analysed in terms of a set of kinetic equations that describe the two-stage aggregation of TMVP with an equilibrium constant K1, and two rate constants k+2 and k-2 for association and dissociation of disks, respectively. The consistency of the analysis suggests that the TMVP assembly proceeds in two steps of: (1) the aggregation of A-proteins into double-layered disks; and (2) the stacking of double-layered disks. The kinetic analysis indicated that the stacking belongs to the lowest range of protein-protein interaction system.

Capsid Proteins↗
PubMed1990

[Aspects of parasternal lymphnode dissection in radical mastectomy for breast cancer].

In order to clarify the surgical aspects for parasternal lymphnode dissection to improve prognosis in patients with breast cancer, we have retrospectively investigated a total of 319 patients with breast cancer who underwent radical mastectomy with parasternal lymphnode dissection. During the 13 years from 1974 to 1986, 418 patients with breast cancer underwent radical mastectomy. Of these, 319 underwent combined dissection of the parasternal lymphnodes. Among these 319 cases, 36 (11.3%) showed pathologically-confirmed positive lymphnode metastasis. In those cases involving a tumor of diameter greater than 5 cm and more than 4 positive metastatic axillar lymphnodes, then the positive parasternal lymphnode metastasis was higher than 30%. The 5-year survival rate was 88.9% for negative parasternal lymphnode metastasis and 44.7% for positive cases (p less than 0.01 logrank test). The standard adjuvant chemotherapy, chemo-endocrine therapy and radiation therapy, each did not significantly affect or improve prognosis. We conclude that parasternal lymphnode positivity is an important factor in radical mastectomy affecting prognosis and a more powerful adjuvant chemotherapy must be developed to improve prognosis.

Breast Neoplasms↗
PubMed1990

Lymphocyte infiltration into normal rat brain following hyperosmotic blood-brain barrier opening.

An investigation was conducted to determine whether lymphocytes were able to infiltrate into the brain parenchyma of normal rats in which hyperosmotic opening of the blood-brain barrier (BBB) had been created by internal carotid infusion of filtered 20% mannitol. Various numbers (1 x 10(6) to 3 x 10(8] of autologous lymphocytes were injected into the internal carotid artery, or via a tail vein, after BBB opening. Lymphocytes were detectable in the brain of rats subjected to high-grade BBB opening and injected with a high number of lymphocytes. Subsets of lymphocytes were examined by immunohistochemical staining using OX19, W3/25 and OX8 monoclonal antibodies. There was no remarkable difference in number between W3/25- and OX8-positive cells. From these results it was suggested that the intensity of BBB opening and the number of lymphocytes flowing in brain vessels are related to the passage of lymphocytes through the BBB.

Animals↗
PubMed1990

Nucleolar organizer regions in meningioma.

Seventy-eight cases of meningioma and related tumors were examined independently using a simple and reproducible argyrophilic method for the demonstration of nucleolar organizer regions (AgNORs) and staining with bromodeoxyuridine monoclonal antibody. The mean number of AgNORs per cell and the bromodeoxyuridine labeling index were shown to be linearly related (r = 0.84, P less than 0.001). The mean AgNOR number was 2.99 for meningeal sarcoma, 2.29 for anaplastic meningioma, 2.08 for hemangiopericytic meningioma. 1.72 for recurrent meningioma without atypical histological findings, and 1.52 for nonrecurrent meningioma. We noted that the mean number of AgNORs reflected the cellular kinetics of a tumor and was related to histological grade and clinical behavior.

Bromodeoxyuridine↗
PubMed1990

Silver colloid staining technique for analysis of glioma malignancy.

A silver colloid staining technique for identifying nucleolar organizer region-associated proteins (Ag-NOR's) was applied to 51 human gliomas. These comprised 20 glioblastomas multiforme, 15 anaplastic astrocytomas, and 16 astrocytomas, in which the mean numbers of Ag-NOR's per cell (+/- standard error of the mean) were 2.51 +/- 0.12, 2.01 +/- 0.10, and 1.76 +/- 0.06, respectively. Significant differences among these were recognized, and the mean number of Ag-NOR's paralleled the degree of histopathological malignancy. In 16 cases, studies were performed of the number of Ag-NOR's and the S-phase fraction by in vitro labeling using antibromodeoxyuridine monoclonal antibody. A linear relationship was demonstrated between these two factors (r = 0.857, p less than 0.001), although some scatter was seen. In 32 adult patients, the correlation between the number of Ag-NOR's and the prognosis was estimated. The results demonstrated that the group containing patients with less than 1.80 Ag-NOR's per cell had a better prognosis than the group with 1.80 Ag-NOR's or more. Thus, the number of Ag-NOR's reflected the degree of histopathological malignancy, S-phase fraction, and prognosis. Silver colloid staining for Ag-NOR's is a simple, rapid, and reproducible method for estimating the proliferative potential of human gliomas without requiring a complicated technique.

Astrocytoma↗
PubMed1990

Correlation of in vitro bromodeoxyuridine labeling index and DNA aneuploidy with survival or recurrence in brain-tumor patients.

There are no previous reports correlating the in vitro bromodeoxyuridine (BUdR) labeling index (LI) with the clinical outcome in patients with brain tumors. The reliability of the LI as a predictor of patient survival or recurrence was examined in this study of 66 human brain tumors (19 gliomas, 18 meningiomas, and 29 others). Anti-BUdR staining was performed on surgically extirpated tumor tissue that had been treated with BUdR as previously described. Correlation of the BUdR LI with patient survival or tumor recurrence rate was carried out by the method of Kaplan and Meier. Deoxyribonucleic acid (DNA) aneuploidy was estimated in 52 cases. The results of this study indicate that BUdR LI values correlated well with the clinical course of patients with brain tumor. In comparison with patients with higher LI's, there was both a significantly higher survival rate for tumors other than meningiomas and a higher recurrence-free rate for meningiomas in patients with LI's of less than 4% and 1%, respectively. Although there was a tendency for patients without tumor aneuploidy to show better survival data than the others, no statistical difference was observed. These results suggest that the in vitro BUdR labeling method is reliable for prediction of a patient's prognosis, whereas prognosis on the basis of DNA aneuploidy alone is uncertain.

Adolescent↗
PubMed1990

[Brush cytology for the evaluation of dry-eye].

A special brush was developed for collection of conjunctival cells with better integrity of the harvested specimens. Using this brush, cells were collected from temporal bulbar conjunctiva of 20 normal eyes and 40 eyes with dry-eye, and were stained by the modified Papanicolau method, Keratinized cells (K) and goblet cells (G) were classified into 5 categories, from (-) to ( ) according to the numbers of the cells observed. Normal eyes were categorized as K (-):16, K(+/-):4, G (+):2, G(++):18, Eyes with dry-eye were K (-):3, K (+/-):8, K (+) 13, K (++):11, K ( ):5, and G (-):7, G (+/-):7, G (+):22, G (++):4. Clinical severity and the rose Bengal score corresponded to these categories. This technique can detect cytological changes in conjunctival cells in terms of shape and quality of staining. Eyes with dry-eye could be evaluated in relation to the numbers of keratinized cells and goblet cells.

Adult↗