PubMed Health⌕ Search

Biomedical subjects

Y Kajiwara

Publications and source records attributed to Y Kajiwara.

At least 19 recordsLinked to original sources
PubMed2003

p16 Gene transfer increases cell killing with abnormal nucleation after ionising radiation in glioma cells.

It is well established that cells synchronised at the G1-S phase are highly radiosensitive. In this study, p16-null human glioma cell lines were induced into G1 cell cycle arrest by adenovirus-mediated p16 gene transfer, and examined for radiation-induced cell killing. Clonogenic analysis and trypan blue extraction test showed that the p16 gene transfer enhanced radiation-induced cell killing in p16-null glioma cell lines. TUNEL assays and pulse-field gel electrophoresis confirmed that the radiation-induced cell killing of p16-transfected cells could be caused by a nonapoptotic mechanism. Gimsa staining demonstrated that irradiation alone or Ax-mock infection plus irradiation results in a slight increase in the frequency of cells with abnormal nucleus, compared to unirradiated uninfected or Ax-mock infected cells. However, Ax-hp16 or Ax-hp21 infection alone modestly increased the frequency of cells with abnormal nucleus (especially bi- and multinucleation), and 4-Gy irradiation of Ax-hp16 or Ax-hp21 infected cells substantially enhanced this frequency. These results suggest that there exists some unknown interaction between radiation and p16 in cytoplasm/membranes, which decreases cytokinesis and promotes abnormal nucleation. Thus, p16 expression prevented radiation-induced apoptosis by promoting abnormal nucleation, thereby leading to another mode of cell death.

Adenoviridae↗
PubMed2002

Detection of a pineoblastoma with large central cyst in a young child.

THE PATIENT: We present the very rare case of a pineoblastoma with large central cyst in a 7-year-old boy who presented with a short history of gradually worsening headache and upward gaze palsy. IMAGING INVESTIGATIONS: On CT and MRI studies, it was seen as a peripherally calcified, irregularly shaped mass with heterogeneous low signal intensity on T1-weighted images and ringed enhancement after gadolinium administration; there was homogeneous high signal intensity on T1-weighted images. DISCUSSION: We discuss differential diagnosis for several types of cystic tumors in the pineal region, including pineoblastomas.

Brain Diseases↗
PubMed2001

Calcium-bindings of wild type and mutant troponin Cs of Caenorhabditis elegans.

Apparent Ca(2+)-binding constant (K(app)) of Caenorhabditis elegans troponin C (CeTnC) was determined by a fluorescence titration method. The K(app) of the N-domain Ca(2+)-binding site of CeTnC was 7.9+/-1.6 x 10(5) M(-1) and that of the C-domain site was 1.2+/-0.6 x 10(6) M(-1), respectively. Mg(2+)-dependence of the K(app) showed that both Ca(2+)-binding sites did not bind competitively Mg(2+). The Ca(2+) dissociation rate constant (k(off)) of CeTnC was determined by the fluorescence stopped-flow method. The k(off) of the N-domain Ca(2+)-binding site of CeTnC was 703+/-208 s(-1) and that of the C-domain site was 286+/-33 s(-1), respectively. From these values we could calculate the Ca(2+)-binding rate constant (k(on)) as to be 5.6+/-2.8 x 10(8) M(-1) s(-1) for the N-domain site and 3.4+/-2.1 x 10(8) M(-1) s(-1) for the C-domain site, respectively. These results mean that all Ca(2+)-binding sites of CeTnC are low affinity, fast dissociating and Ca(2+)-specific sites. Evolutional function of TnC between vertebrate and invertebrate and biological functions of wild type and mutant CeTnCs are discussed.

Aminoquinolines↗
PubMed2001

Total synthesis of natural dysidiolide.

Dysidiolide (1), a novel sesterterpenoid previously isolated from the Caribbean sponge Dysidea etheria de Laubenfels, inhibits the action of the protein phosphatase, cdc25A. The authors establish a novel total synthesis of natural dysidiolide (1) using intramolecular Diels-Alder reaction as the key step from optically active cyclohexenone 3. Decalin, the core structure of 1, was constructed by intramolecular Diels-Alder reaction of the diene ester generated by elimination of the phenyl sulfoxide group from sulfoxide ester 6 prepared from cyclohexenone 3. Diastereoselective methylation at C-7, alkylation at C-6, and deoxygenation of C-12 and C-24 positions gave the fully substituted bicyclic core of 1. The two side chains of the bicyclic core were further extended so as to afford natural dysidiolide (1). The total yield of this synthesis exceeds that of previous syntheses of 1.

4-Butyrolactone↗
PubMed2001

The bZIP-like motif of hnRNP C directs the nuclear accumulation of pre-mRNA and lethality in yeast.

The hnRNP C protein tetramer cooperatively binds 230 nt increments of pre-mRNA in vitro in a salt-resistant manner and is located along the length of vertebrate transcripts in vivo. Based on these and other findings it has been suggested that hnRNP C functions as a chaperonin to maintain long lengths of RNA topologically single-stranded and accessible to splicing factors. We report here that human C protein is lethal when expressed in the yeast Saccharomyces cerevisiae. Through a series of fluorescent immunolocalization studies, lethality was observed to be associated with the rapid nuclear accumulation of both C protein and yeast pre-mRNA. Studies using various protein constructs and the two hybrid assay reveal that these events are dependent on the basic 40 residue high-affinity RNA binding domain and its contiguous leucine zipper-like motif (the bZLM, residues 140-214). Additionally, equilibrium binding studies have shown that the bZLM is the determinant of C protein's salt-resistant RNA binding mode. Taken together, these findings further distinguish the bZIP-like domain as the major determinant of C protein's high-affinity interaction with RNA, oligomerization, and its highly cooperative RNA binding activity. Finally, these findings indicate that yeast and vertebrates may possess a conserved mechanism for general import of RNP although a true homolog to vertebrate C protein appears not to exist in yeast. Lethality is likely due to the absence in yeast of specific mechanisms for the removal of human C protein from nascent transcripts.

Active Transport, Cell Nucleus↗
PubMed2000

Herniation through both Winslow's foramen and a lesser omental defect: report of a case.

The herniation of small bowel through Winslow's foramen is a rare type of internal hernia which can cause ileus; however, a hernia traversing the lesser sac is even more unusual. To the best of our knowledge, only 25 cases of herniation through Winslow's foramen and 10 cases of lesser sac hernia have been reported in the Japanese literature. We describe herein the case of a 33-year-old man who presented to our hospital complaining of abdominal pain in whom a plain abdominal radiograph revealed small bowel gas with air-fluid levels, suggesting ileus. Following admission, an ileus tube was inserted, but the intestinal shadow did not improve and surgery was performed based on suspicion of an internal hernia. Approximately 100 cm of ileum was found to have herniated through a defect in the lesser omentum after passing through Winslow's foramen. Since the herniated bowel was viable, manual reduction without resection was performed. The patient had a satisfactory postoperative course, and was discharged on postoperative day 11. There are many unknown aspects surrounding the etiology of Winslow's foramen hernia and lesser sac hernia, and although internal hernia is a rare cause of ileus, its possibility should be kept in mind.

Adult↗
PubMed2000

Vitamin K contents in liver tissue of hepatocellular carcinoma patients.

Serum protein induced in vitamin K absence-II (PIVKA-II) is used as a tumor marker because it increases at a notably higher rate in patients with hepatocellular carcinoma. To clarify the mechanism causing the elevation of serum PIVKA-II, we measured the contents of vitamins K1 (phylloquinone, PK) and K2 (menaquinone, MK) (MK-4, MK-5, MK-6, MK-7, MK-8, MK-9, MK-10) in liver tissue resected from 21 hepatic cancer patients (12 patients with hepatocellular carcinoma and 9 patients with metastatic hepatic cancer), using HPLC combined with coulometric reduction and fluorometric detection. In the cancerous tissue of hepatocellular carcinoma patients, PK, MK-7, MK-8, and MK-10 were significantly lower than that found in the noncancerous tissue. Furthermore, MK-6, MK-7, MK-8, and MK-10 in the cancerous tissue of hepatocellular carcinoma patients were significantly lower than that in the cancerous tissue of metastatic hepatic cancer patients. These data suggested that one of the mechanisms of the elevation of serum PIVKA-II levels in hepatocellular carcinoma patients is a vitamin K deficiency in the local cancerous tissue.

Aged↗
PubMed2000

Antithrombin therapy for severe preeclampsia: results of a double-blind, randomized, placebo-controlled trial. BI51.017 Study Group.

A double-blind, randomized, placebo-controlled trial was conducted to evaluate whether treatment with Antithrombin (AT) concentrates improved the clinical and perinatal outcome in patients with severe preeclampsia. Severe preeclamptic patients (24 to 35 weeks of gestation. Gestosis Index (GI) > or = 6 points) were randomized into two groups: 66 received AT and 67 received placebo. There were no statistical differences in the clinical profiles of the two groups. Study drugs were given intravenously once daily for 7 consecutive days. Maternal symptoms were evaluated from the difference of GI between before and after treatment, and fetal findings were evaluated from the changes of the biophysical profile score and the estimated fetal weight gain. Improvement was significantly greater in the AT group for both the GI (p = 0.020) and the estimated fetal weight gain (p = 0.029). The improvement of coagulation parameters was also evaluated. The D-dimer levels increased significantly in the placebo group (p = 0.026), but did not change in the AT group. Gestation was significantly prolonged (p = 0.007), and the number of low-birth weight infants was significantly smaller (p = 0.011) in the AT group. No adverse events related to AT were observed. It is revealed that AT concentrate therapy for preeclampsia is effective and safe, leading to an improved perinatal outcome.

Acute Disease↗
PubMed1999

Effects on reproduction and fetal development of female rats treated subcutaneously with a surfactant, polyoxyethylene(10)nonylphenyl ether(NP-10), for 15 weeks.

A surfactant NP-10 was administered subcutaneously to 7-week-old Jcl:Wistar female rats at dose levels of 2 and 20 mg/kg/day for 15 weeks to assess its effects on their reproductive ability and fetal development, and on the growth, behavior and functions of the offspring they delivered. In the general condition of the F0 dams, changes that were considered to be the local irritation effect of the test substance, such as scab formation and loss of hair at the test substance administration site in the 2 and 20 mg/kg groups and induration of the skin at the test substance administration site in the 20 mg/kg group were observed. Whitish changes of the subcutis were detected at the test substance administration site in the 2 and 20 mg/kg groups and adhesion of abdominal organs in the 20 mg/kg group in the necropsy findings. In addition, an increase was observed in body weight and in food consumption in the 20 mg/kg group. The reproductive ability test failed to reveal any evidence of an effect that could be ascribed to the test substance. The observations at cesarean section or external, visceral and skeletal examinations revealed no effects attributable to the test substance in the F1 fetuses. The observations on the day of birth and during the period of lactation, external examination, physical development test, general condition, body weight and necropsy findings for F1 and F2 offspring and reflex test, open-field test, water-maze test, organ weight and reproductive ability test performed on the F1 offspring failed to reveal any evidence that could be ascribed to the test substance. These results indicate that under the conditions of this study, NP-10 had no effect on the reproductive ability of females or the fetal development or growth, behavior and functions of their offspring.

Abnormalities, Drug-Induced↗
PubMed1999

[A case of chordoid meningioma].

Chordoid meningioma is a very rare variant, especially in adults. We report an adult case of chordoid meningioma. A 52-year-old man was admitted to our hospital due to right hemiparesis. MRI revealed a left temporal convexity mass that showed two structures; the cerebral layer was shown as an isointensity area on T1WI and T2WI, and the dural layer seemed relatively hypointense on T1WI and hyperintense on T2WI. The tumor was well enhanced with gadolinium, especially on the dural side. A left external carotid arteriogram showed tumor stains with feeding vessels from the left middle meningeal artery. The tumor was totally removed via fronto-temporal craniotomy. Histological examination of the surgical specimen revealed two different structural components, meningothelial meningioma on the cerebral side, and chordoid meningioma on the dural side, consisting of clustering spindled cells and partly vacuolated ones in the mucoid stroma. In immunohistochemical examination, tumor cells showed positive staining for vimentin and epithelial membrane antigen (EMA), and negative for cytokeratin. From the above findings, this case was diagnosed as chordoid meningioma in an adult, a very rare variant of meningioma.

Chordoma↗
PubMed1998

T cell proliferation-augmenting activities of the gene 3 protein derived from a phage library clone with CD80-binding activity.

We have isolated a phage clone, F2, by panning a phage library with a CTLA4-conformation recognizing mAb (anti-CTLA4 mAb). The unique sequence of 15 amino acids with an internal disulfide bond was inserted in the gene 3 proteins of F2 phage clone (F2-g3p). We show here that 1) F2-g3p was recognized with anti-CTLA4 mAb but not with anti-CD28 mAb, and 2) F2-g3p bound to CD80 but not to CD86. The surface plasmon resonance analysis showed that F2-g3p strongly bound CD80. F2-g3p inhibited the binding of CTLA4 to CD80 but not to CD86. In contrast, F2-g3p weakly inhibited the binding of CD28 with CD80. When hen egg lysozyme (HEL)-primed lymph node cells were stimulated with HEL in the presence of F2-g3p in vitro, cell proliferation was highly potentiated. In the absence of antigenic stimulation, F2-g3p induced no T cell proliferation, indicating the costimulatory nature of F2-g3p. The T cell-augmenting activity of the F2 clone was eliminated when the F2 clone was preincubated with CD80-Ig before the addition to the cultures, indicating the involvement of CD80-binding in the F2-g3p-mediated immunopotentiation. Thus, the F2 motif conferred CD80-binding activity and an immunoregulatory function to the g3p.

Abatacept↗
PubMed1998

Natural course of HGV infection in haemophiliacs.

The natural course of hepatitis G virus (HGV) infection was clarified in 70 haemophiliacs by testing for HGV RNA and antibodies against HGV envelope protein (anti-E2). None of 12 patients treated with only virus-inactivated coagulation factors were infected with HGV. Of 58 patients who received non-inactivated products, 28 (48%) were positive for HGV RNA and/or anti-E2. Of 16 patients with anti-E2, 14 were negative for the viral RNA, and had recovered from HGV infections. HCV antibodies were detected in 59 patients, and eight patients were successively negative for HCV RNA. Thus, the recovery rate of HGV infection (14/28, 50%) was higher than that of HCV (8/59, 14%) (P<0.001). Longitudinal study revealed that anti-E2 developed either during viraemia or some years after seronegativity for HGV RNA. Hence the antibody response itself seemed not to play a major role in the clearance of HGV though anti-E2 was associated with the clearance of HGV RNA. In conclusion, HGV and HCV are prevalent in patients treated with unsterilized coagulation factor concentrates. However, in contrast to HCV, spontaneous recovery is frequently observed in HGV infections.

Adolescent↗
PubMed1998

Effects of oral hyposensitization with recombinant Der f2 on immediate airway constriction in a murine allergic model.

Recombinant Der f2 (rDer f2) has recently been developed as a promising allergen for the diagnosis and immunotherapy of house-dust mite allergy, and studies in immunology. The aim of the present study was to evaluate whether oral administration of rDer f2 could suppress an immediate allergic reaction in mice sensitized with mite allergen. We developed a murine allergic model that showed bronchoconstriction after inhalation of rDer f2, and studied the effect of oral administration of rDer f2 on the reaction. Seven week old male A/J mice were intranasally immunized with rDer f2 12 times. Sensitized mice showed anti-rDer f2 immunoglobulin (Ig)E production and immediate airway constriction after inhalation of 10 mg.mL(-1) of rDer f2, as determined by the Konzett-Rössler method. Immunized animals were divided into three groups, and fed phosphate-buffered saline (PBS), 0.1 mg.day(-1), or 1 mg.day(-1) of rDer f2 for 4 weeks, respectively. Seven days after the last feeding, the mice were examined for their immediate response. Animals fed with 1 mg.day(-1) rDer f2 showed significantly reduced bronchoconstriction after inhalation of both 2 mg.mL(-1) and 10 mg.mL(-1) of rDer f2 compared with PBS-fed mice. Similar results were obtained when we examined mice 10 weeks after the last feeding. Reactions in the 0.1 mg.day(-1) rDer f2-fed group also tended to decrease in comparison with PBS-fed animals. Plasma anti-rDer f2 IgE, IgG1, IgG2a, and IgG2b levels were not changed by feeding with rDer f2. We conclude that recombinant Der f2 exhibits both sensitizing and hyposensitizing activities in mice. rDer f2 may be useful in immunotherapy and diagnosis of house-dust mite allergy.

Administration, Oral↗
PubMed1998

[Differentiation between benign and malignant breast lesions using fat-suppressed dynamic MR imaging].

PURPOSE: To assess the value and problems of fat-suppressed dynamic MR imaging in differentiating between benign and malignant lesions. MATERIALS AND METHODS: In twenty-nine patients who underwent excisional biopsy or surgical resection, fat-suppressed dynamic MR imaging was performed with a 0.5 T superconducting magnet. Pre-and postcontrast 3D-spoiled gradient echo sequences were employed with fat suppression. We calculated and evaluated the contrast-to-noise ratio (CNR) and contrast enhancement ratio (CER) at each contrast determination time (CDT), which is the intermediate time in the scan. RESULTS: Time intensity curves of CNR showed no statistically significant difference between cancers and other benign lesions. The difference in CER between malignant and benign disease was highly significant (P = .006) at CDT 45 sec., but there was great overlap in the time intensity curve of CER after CDT 45 sec. CONCLUSION: When we attempt to differentiate malignant from benign breast lesions by dynamic MR imaging, comparison of CNR is impertinent, and we should evaluate the differential diagnosis of cancer versus benign lesions by means of CER at CDT points of about 45 sec.

Adolescent↗
PubMed1997

Inhibition of airway inflammation in rDer f 2-sensitized mice by oral administration of recombinant der f 2.

Recombinant Der f 2 (rDer f 2) is a promising new allergen expected to improve the diagnosis and immunotherapy of house dust mite allergy and to further immunological studies. To evaluate the hyposensitizing activity of rDer f 2 to mite allergy, we examined the effect of its oral administration on allergic inflammation in A/J mice immunized with mite allergens. A/J mice immunized with rDer f 2 alone or rDer f 2 + crude mite extract were orally given 0 (control), 0.01, 0.1, or 1 mg/day of rDer f 2 for 4 weeks, followed by an antigen inhalation challenge. Twenty-four hours after rDer f 2 inhalation, control animals experienced severe leukocyte influx into the airway. The infiltrating cells were mainly neutrophils, with some eosinophils and lymphocytes. The concentrations of IL4, IFNgamma, and soluble ICAM-1 in the bronchial alveolar lavage fluid increased twofold compared with values before rDer f 2 inhalation. In contrast, inflammation was significantly suppressed in mice given 1 mg/day of rDer f 2 orally for 4 weeks and partially suppressed in those fed 0.1 mg/day of the antigen. Plasma anti-rDer f 2 antibody levels were unchanged by oral rDer f 2 treatment. Mite extract inhalation challenge provoked neutophilia in rDer f 2 + mite-sensitized control mice, and this allergic reaction tended to decrease in sensitized mice fed 1 mg/day of rDer f 2 orally for 4 weeks. We conclude that rDer f 2 has hyposensitizing activities and may be useful in immunotherapy for house dust mite allergy.

Administration, Oral↗
PubMed1997

Improvement of carcinogen detection in the BALB/3T3 cell transformation assay by using a rich basal medium supplemented with low concentration of serum and some growth factors.

To improve the detection sensitivity and reproducibility of the transformation assay using BALB/3T3 cells, we scrutinized a new assay method in which the cells were replated in a medium containing a low concentration of serum after carcinogen treatment. Dulbecco's modified Eagle's medium plus Ham F12 (DME.F12) supplemented with a mixture of insulin, transferrin, ethanolamine and sodium selenite (ITES) and a low concentration of fetal calf serum (FCS) caused transformation at a high frequency with a high reproducibility. The transformation frequency in the culture treated with N-methyl-N'-nitro-N-nitrosoguanidine was the highest in DME.F12 medium containing ITES and 2% FCS, and it decreased at either a lower or higher FCS concentration. Moreover, the transformation frequency was not markedly influenced by the difference in lot of FCS, probably due to reduction in FCS concentration. According to the present method, the transformation frequency was 2-times higher and transformed foci appeared much earlier than by the method using the original medium. Next, we examined some geno- and non-genotoxic carcinogens, and some genotoxic non-carcinogens to confirm the availability of this method for predicting potential carcinogens. This method could precisely identify not only genotoxic carcinogens but also non-genotoxic carcinogens and genotoxic non-carcinogens. In conclusion, these findings suggest that this method is useful for detection of chemical carcinogens because it provides high sensitivity, high reproducibility and accurate predictivity, without the requirement of 12-O-tetradecanoylphorbol 13-acetate as a promoter, making it harmless to examiner.

3T3 Cells↗
PubMed1997

Pathology of chronic hepatitis C in children. Child Liver Study Group of Japan.

Limited information is available regarding the histology of hepatitis C virus infection in children. The aim of this study was to determine the histological pattern of chronic hepatitis C (CHC) in children, and liver biopsy specimens from 109 pediatric patients with CHC were examined. Each biopsy specimen was evaluated based on a numerical scoring system for the stage of fibrosis (1-4), the grade of portal/periportal necroinflammation (0-4), the grade of lobular necroinflammation (0-4), and their sum (final grade). The histological lesions considered to be characteristic of chronic hepatitis were also evaluated. None of the children had liver cirrhosis, and 105 cases (97%) were stage 1 or 2. Only 4 children were stage 3. Two of these 4 cases showed hemosiderosis. A significant correlation was observed between the staging score and the final grade in the pediatric patients (r = .59; P < .0001). The histological characteristics of adult CHC, such as lymphoid aggregate, bile duct injury, and fatty changes, were also observed in the children. In conclusion, the majority of children with CHC presented with mild fibrosis, but a few showed CHC with lobular distortion and hemosiderosis. Frequent blood transfusion may aggravate hepatic lesions in pediatric CHC.

Adolescent↗