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Biomedical subjects

K Kikuchi

Publications and source records attributed to K Kikuchi.

At least 739 records · Page 41Linked to original sources
PubMed1993

Demonstration of selective protein complexes of p53 with 73 kDa heat shock cognate protein, but not with 72 kDa heat shock protein in human tumor cells.

It has been demonstrated that p53, especially, mutant p53 (mp53), makes protein complexes with major heat shock proteins hsp72/hsc73. However, there is no direct evidence showing whether hsp72 or hsc73 could bind preferentially to p53. In the present study, using TYKnu human ovarial carcinoma cells and monoclonal antibodies reacting specifically to hsp72/hsc73, we were able to find the selective protein complex formation with p53, presumably mp53, and hsc73, but not in the case of p53 and hsp72. The p53-hsc73 protein complexes dissociate with the addition of ATP, indicating that the dissociation is dependent upon the ATP-hydrolysis. These data suggest that hsc73 rather than hsp72 plays an important role in the yet undefined mechanism of disregulated cell growth control by mp53.

Adenosine Triphosphate↗
PubMed1993

IL-2 induces transient and specific decrease in cytosolic protein phosphatase PP1 activity in murine T cell lines.

In the IL-2-dependent murine cytotoxic T cell line CTLL-2, IL-2 induced a rapid and transient decrease in Co(2+)-trypsin-treated activity of protein phosphatase PP1. The PP1 activity declined to a minimum level, being 70% of control value, in 20 min after the addition of IL-2 but recovered to the control level within 45 min. The decrease of PP1 activity was dependent on IL-2 concentration and occurred specifically in cytosolic fraction. Similar alteration was observed in IL-2 sensitive murine T-lymphoblasts. Neither activity of protein phosphatase PP2A nor PP2C showed alteration during the IL-2 stimulation. These results suggest that PP1 plays an important role in early events of the intracellular growth signaling from the IL-2 receptor.

Animals↗
PubMed1993

Detection of nitric oxide production from a perfused organ by a luminol-H2O2 system.

Nitric oxide, thought to be the endothelium-derived relaxing factor (EDRF), is involved in intra- and intercellular signalling in various tissues. A system for the continuous detection of NO in the picomolar range from a perfused organ is described. The detection is based upon the chemiluminescence reaction between NO and the luminol (5-amino-2,3-dihydro-1,4-phthalazinedione)-H2O2 system. The chemiluminescence is due to the formation of peroxynitrite from NO and H2O2. The luminol-H2O2 system is specifically reactive to NO, so that other nitrogen-containing compounds, (organic nitrite, organic nitrate, and thio-nitroso compounds) or endothelium-derived compounds do not interfere. The limit of determination was approximately 100 fM. This system has been used to measure continuous NO release from isolated perfused rat kidney and the simultaneous changes of perfusion pressure. In Wistar rats basal NO release was 85 +/- 11 fmol/min-1 (g of kidney weight)-1 (39 pM in the perfusate), and acetylcholine increased NO release dose dependently with a concomitant pressure reduction. The changes in NO release were always associated with mirror image changes in the perfusion pressure. Simple pressure reduction did not interfere with the chemiluminescence. Precise titration data as well as results of some preliminary experiments using this method are presented.

Animals↗
PubMed1993

Analysis of T-cell receptor V region gene usage of cytotoxic T-lymphocytes and tumor-infiltrating lymphocytes derived from human autologous gastric signet ring cell carcinomas.

To determine the T-cell receptor (TCR) V alpha/V beta gene usage of the human autologous gastric tumor-specific cytotoxic T-lymphocytes (CTLs), we first established two pairs of tumor cell lines, HST2 and SSTW, from the malignant peritoneal effusions of signet ring cell carcinomas and their peripheral blood lymphocyte-derived tumor-specific CD8-positive CTL lines, TcHST2 and TcSSTW. TCR V alpha/V beta gene usage from these CTL was examined using the reversely transcribed-polymerase chain reaction method, demonstrating that the V alpha 7, V alpha 12, and V beta 20 transcripts were commonly detected. The fact that repeated antigenic stimulation by mixed lymphocyte-autologous tumor cell cultures brought about the specific cytolysis and the restricted TCR usage of TCR V alpha 7, V alpha 12, and V beta 20 strongly suggests that these TCR V region products participated in T-cell-cancer interaction. This restricted TCR V gene usage in the gastric signet ring cell carcinomas led us to examine further the frequency of TCR V alpha/V beta usage in 11 cases of in vivo tumor-infiltrating lymphocytes with this particular type of tumor. The data showed that V alpha 7, V alpha 12, V beta 6, and V beta 20 were also predominantly expressed among these tumor-infiltrating lymphocytes in vivo. However, it seemed that T-cells with these TCR V region products are not specific for the gastric signet ring cell carcinomas, since they also frequently infiltrate into noncancerous lesions, such as peptic ulcers. These data may suggest that T-cells with certain TCR V alpha/V beta products could preferentially infiltrate into the stomach tissue, while some of these T-cells may be cytotoxic to the neoplastic autologous tumor cells.

Adenocarcinoma, Mucinous↗
PubMed1993

Protein interaction of retinoblastoma gene product pRb110 with M(r) 73,000 heat shock cognate protein.

Both the tumor suppressor gene products, the retinoblastoma sensitivity gene product pRb110 and p53, are found in oligomer complexes with the oncogene products of the DNA tumor viruses. It has been demonstrated that p53 binds to the M(r) 70,000 heat shock protein family. However, the protein association of pRb110 with the M(r) 70,000 heat shock protein family is not yet known. We analyzed the immunoprecipitates made with TYK-nu human ovarial carcinoma cell lysate and anti-pRb110 or anti-heat shock protein monoclonal antibodies. In this paper, we demonstrate that pRb110 is associated with the M(r) 73,000 heat shock cognate protein, but not with the M(r) 72,000 heat shock protein. This selective protein association was also detected in HeLa cervical carcinoma cells. Furthermore, the protein complexes of the M(r) 73,000 heat shock cognate protein and pRb110 were dissociated with the presence of ATP, but not with ADP and the nonhydrolyzable ATP analogue, ATP gamma S. This indicates that the dissociation is dependent on the ATP hydrolysis. These data may suggest an as yet undefined important role of M(r) 73,000 heat shock cognate protein in the cell growth control in collaboration with pRb110.

Adenosine Triphosphate↗
PubMed1993

Antihistone antibodies in patients with localized scleroderma.

OBJECTIVE: To study the prevalence and antigen specificity of antihistone antibodies (AHA) in localized scleroderma. METHODS: Forty-nine serum samples from patients with localized scleroderma were examined by an enzyme-linked immunosorbent assay (ELISA) and by immunoblotting. RESULTS: By ELISA, AHA were demonstrated in 47% (23 of 49) of patients with localized scleroderma and in 87% (13 of 15) of patients with generalized morphea. Immunoblotting revealed that the predominant antigens were histones H1 and H3. The presence of AHA correlated with that of anti-single-stranded DNA antibody. CONCLUSION: Some of the major antigens for antinuclear antibodies in patients with localized scleroderma are histones.

Adolescent↗
PubMed1993

Establishment of apoptosis-inducing monoclonal antibody 2D1 and 2D1-resistant variants of human T cell lines.

A monoclonal antibody (mAb), 2D1(IgM), was identified for its anti-proliferative effect on human T leukemia cell line, SUP-T13. The cells bound with 2D1 showed DNA ladder patterns of oligonucleosomes, demonstrating apoptosis. Peripheral mononuclear cells activated by phytohemagglutinin or OKT3 induced expression of 2D1 antigen and were growth-inhibited by the antibodies. Among the cell lines tested, T cell lines tended to be growth-inhibited by the antibodies. Epstein-Barr virus-transformed B cells were reactive with 2D1, but were not growth-inhibited by the antibodies. We established stable 2D1-resistant variants LAC2D1R and JKT2D1R from the original SUP-T13 and Jurkat T cell lines, respectively. These variant cells demonstrated phenotypes identical to the original cells, including reactivity to 2D1 and expression of cytoplasmic Bc1-2 protein. The 2D1-resistant cells were as sensitive as the original cells to the other apoptosis-inducing stimuli, such as gamma-irradiation or calcium ionophore A23187. However, the 2D1-resistant variants were also insensitive to anti-Fas, another apoptosis-inducing mAb. Binding of 2D1 was blocked by anti-Fas mAb, suggesting that 2D1 reacts with an epitope of human Fas molecules. The present results demonstrate that a 2D1-reactive, but not 2D1-sensitive, population may exist in highly 2D1-sensitive human leukemia T cells and that pairs of 2D1-sensitive and 2D1-resistant cells are useful in the biochemical analysis of Fas-mediated apoptosis in human T cells.

Antibodies, Monoclonal↗
PubMed1993

Multifactorial regulation of IGF-I gene expression.

Insulin-like growth factor-I (IGF-I) is a highly conserved 70-residue circulating peptide with diverse biological effects. In mammals IGF-I is an essential mediator of normal postnatal growth and its expression is influenced by hormonal, nutritional, tissue-specific, and developmental factors. Recent studies have demonstrated that the IGF-I gene is more complicated than might have been predicted from its simple protein sequence. In rats and in humans the single-copy six-exon gene is transcribed by adjacent promoters into nascent RNAs with different 5' leader sequences that undergo both alternative RNA splicing and differential polyadenylation to yield multiple mature transcripts. These observations suggest that trophic agents may modulate expression of IGF-I at any of several nodal points. In this report we review several of the mechanisms responsible for regulating production of IGF-I in the rat. During neonatal development IGF-I gene transcription is progressively activated, leading to a rise in both hepatic IGF-I mRNA and in serum IGF-I. The induction of IGF-I expression is limited to mRNAs directed by promoter 1, the more 5' of two rat IGF-I gene promoters, and precedes the ontogenic appearance of liver growth hormone (GH) receptors, indicating that mechanisms independent of GH activate IGF-I expression during early postnatal life. By contrast, in adult GH-deficient rats, a single intraperitoneal injection of GH causes a prompt rise in IGF-I gene transcription that is mediated equivalently by promoters 1 and 2.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1993

A cell-type-specific transcription enhancer of type 16 human papillomavirus (HPV 16)-P97 promoter is defined with HPV-associated cellular events in human epithelial cell lines.

Expression of the early genes of human papillomavirus type 16 (HPV16) is known to be highly restricted to epithelial cells. This report describes the molecular basis of HPV16 epitheliotropism at the transcriptional level. A series of 5'-end deletion mutants of the long control region (LCR) located upstream of the HPV16 early genes were tested in a transient expression assay using various human epithelial and fibroblastic cell lines. The specific region termed the cell-type-dependent regulatory element (CTRE) was found to function as an enhancer in some of HPV-associated human epithelial cell lines, but not at all in HPV-free human epithelial cell lines. No LCR-associated enhancer activity was detectable in fibroblastic cell lines. The CTRE was mapped at a distinct region upstream from the previously proposed proximal keratinocyte dependent enhancer (KD). The CTRE augmented transcription initiated from the autologous P97 promoter as well as from a heterologous promoter in a orientation-independent manner. Within the CTRE, there are three copies of the consensus nuclear factor-1 (NF1) binding site. Using CTRE containing mutations in each of the NF1-sites, it was demonstrated that all of these NF1-sites were necessary for a full enhancer activity in the HPV-associated human epithelial cell line. This suggests that the CTRE plays a critical role in the cell-type specific expression of HPV16-early gene at the level of transcriptional regulation.

Animals↗
PubMed1993

Pharmacokinetics and beta-blocking effects of transdermal timolol.

The pharmacokinetic profiles of transdermal timolol 6 and 24 mg (as 5 and 20% w/v patches) was studied in four healthy young volunteers. To assess its bioavailability, the pharmacokinetics of an IV infusion of timolol maleate 5 mg was also determined in the same subjects. When the 20% (w/v) timolol patch was applied, the mean bioavailability was 74.4%. Plasma timolol concentrations were below the detection limit when a 5% patch was applied to the same skin area in all four subjects, except for one in whom the bioavailability was 23.6%. Weak erythema developed at the application site in all of the volunteers after application of the 20% (w/v) patch. However, erythema did not develop in any volunteer when the 5% patch was applied. The beta-blocking effect was determined by exercise testing. Similar plasma levels generated similar changes in exercise-induced heart rate after the transdermal and intravenous administration of timolol.

Administration, Cutaneous↗
PubMed1993

Gastric acid inhibits antral phase III activity in duodenal ulcer patients.

Fourteen patients with duodenal ulcers and eight healthy volunteers were examined to measure interdigestive gastroduodenal motility and plasma motilin. In order to study the effects of gastric acid on the gastroduodenal motility, 20 mg of famotidine was administered intravenously. The motility index of the gastric antrum and the duodenum, as well as the pH in the duodenal bulb were calculated. The duodenal pH was significantly lower and the gastric motility index was significantly weaker before the duodenal interdigestive migrating complex (IMC) in the ulcer patients than in the controls. Motilin levels increased before the duodenal IMC and decreased afterwards in both groups. Famotidine significantly increased the duodenal pH and the gastric motility index before the IMC, but no changes in the motilin level were noted. We conclude that duodenal ulcer patients have duodenal hyperacidity that results from increased inflow from the antrum and antral hypomotility during the gastric IMC and that these changes are normalized by the administration of famotidine. These results suggest that gastric acid inhibits antral contraction during the gastric IMC.

Adult↗
PubMed1993

Modified bifrontal interhemispheric approach to aneurysms of the anterior communicating artery with the use of a trephine craniotomy. A review of personal experience with 25 cases.

A modified microsurgical bifrontal interhemispheric approach (small trephine craniotomy) for clipping of aneurysms of the anterior communicating artery (ACoA) is described. This approach has been used in a series of 23 patients with ACoA and 2 patients with distal anterior cerebral artery aneurysms. Feasibility, indications and problems related to this approach to ACoA aneurysms are assessed. Twenty-one patients (84%) made an excellent or good recovery. The result was poor in an 80-year-old patient who was in grade 3 pre-operatively. Three patients of this series died: one of them was pre-operatively in grade 4 and died from pneumonia; the other two died as consequence of unrelated ailments. Incidence and extent of vasospasm was within the normal range, corresponding to the amount and distribution of subarachnoid blood clots. From our experience it can be concluded that this approach is safe and feasible for patients with ACoA aneurysms graded 1-2 (Hunt-Kosnik's grading system) and evaluated as group 1-2 of Fisher's CT classification. But it is not recommended for patients with larger amounts of subarachnoid blood clots. Advantages of this microapproach to ACoA aneurysms are: a) minimal brain damage, b) adequate visualization and anatomical orientation, c) preservation of the olfactory nerves and the gyrus rectus, d) reduced operative time, e) easy clip application to aneurysms pointing in any direction.

Adult↗
PubMed1993

Acquired growth hormone deficiency due to pituitary stalk transection after head trauma in childhood.

Two patients are reported with growth hormone deficiency due to head trauma in childhood. Although their injuries were outwardly only slight and there was no loss of consciousness and no subsequent neurological deficits, they exhibited gradual growth retardation from the time of the trauma. Provocative endocrinological tests showed growth hormone deficiency and MRI showed transection of the pituitary stalk. These findings suggest that ordinary head trauma, as well as perinatal insult and congenital abnormalities, could be a cause of growth hormone deficiency.

Child↗
PubMed1993

Effect of follicle cells on in vitro fertilization of pig follicular oocytes.

We investigated the effect of cumulus and granulosa cells (follicle cells) on in vitro fertilization of pig follicular oocytes matured in vitro. Oocytes surrounded by cumulus and connected with a piece of parietal granulosa cells (complexes) were matured in vitro for 46hours and were then divided into 4 groups: Group I oocytes were surrounded by expanded cumulus and granulosa cells; Group II oocytes were surrounded by expanded cumulus cells; Group III were denuded oocytes; and Group IV were denuded oocytes with cumulus cells from other complexes. After incubation for 4 hours and 40 minutes with frozen, thawed and preincubated pig epididymal spermatozoa, the oocytes were cultured for 5 hours and 20 minutes. When oocytes were inseminated in the presence of cumulus cells, the penetration rates were higher (92.5% for Group II and 89.5% for Group IV) than when cumulus cells were not used for insemination (Group III, 66.8%) or when oocytes with follicle cells were inseminated (Group I, 72.3%). Denudation of follicle cells before insemination (Group III) decreased the percentage of male pronuclear formation (50.8%) compared with that of oocytes surrounded by follicle cells (66.7% for Group II and 80.2% for Group I). These results support the ability of a moderate number of follicle cells to facilitate sperm penetration of pig follicular oocytes and male pronuclear formation.

Journal Article↗