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N Kanayama

Publications and source records attributed to N Kanayama.

At least 37 records · Page 2Linked to original sources
PubMed2000

Pharmacologic doses of interleukin 8 suppositories induce follicular maturation in rabbits.

Interleukin 8 (IL-8) is a neutrophil chemoattractant/activating factor that plays a role in the ovarian physiology leads to investigate the effects of IL-8 on follicular maturation. Experiments were conducted using suppositories containing 100 ng, 200 ng, 400 ng IL-8, 500 microl Witepsol-base (control), human menopausal gonadotropin (im) and conjugate of fluorescein isithiocyanate-labelled IL-8. The levels of IL-8 in ovarian fluid were also measured. Histology of ovaries treated with 200 ng IL-8 showed large antral follicles filled with follicular fluid. The theca layer was divided into an interna and an externa with large extracellular spaces. The granulosa cells were loosened and appeared to be detaching from the granulosa layer. Neutrophils were localized predominantly in the theca and medulla (P<0.0001, P<0.004), and relative collagen concentration was significantly decreased in ovaries of 200 ng IL-8 (P<0.0001) compared with controls. The IL-8 was detected in ovarian fluid after 6 h (P<0.0001), 12 h (P<0.001), and 18 h (P<0.01) compared with 0 h. Fluorescein isithiocyanate-labelled IL-8 conjugate was seen in the follicular wall and endometrium. We conclude that pharmacological dosage of exogenous IL-8 exerts an effect on follicular maturation through granulocyte chemotaxis and activation.

Animals↗
PubMed2000

Increased concentrations of plasma neuropeptide Y in patients with eclampsia and preeclampsia.

OBJECTIVE: Epinephrine and norepinephrine are associated with the hyperstimulation of the sympathetic nervous system. Neuropeptide Y is a potent vasoconstrictive substance that is released in response to sympathetic nerve stimulation. STUDY DESIGN: The concentrations of plasma neuropeptide Y in pregnant patients with eclampsia (n = 8), preeclampsia (n = 8), and normotension (n = 8) were measured by radioimmunoassay on admission and 6 days after delivery. Correlations between plasma concentration of neuropeptide Y and mean arterial blood pressure were also evaluated in these patients on admission and 6 days after delivery. RESULTS: The plasma level of neuropeptide Y in women with eclampsia (P <.001) and preeclampsia (P <.003) was found to be significantly elevated with respect to that in normotensive pregnant women. At 6 days after delivery the concentration of plasma neuropeptide Y was significantly decreased in women with eclampsia, women with preeclampsia, and women with normotensive pregnancies compared with the value measured on admission (P <.0001, P <.0001, and P <.002, respectively). At admission the plasma neuropeptide Y level was positively correlated with mean arterial blood pressure in women with eclampsia and preeclampsia. However, no significant correlations were observed between plasma neuropeptide Y concentration and mean arterial blood pressure both at admission and 6 days after delivery in normotensive pregnant women and 6 days after delivery in women with eclampsia and preeclampsia. CONCLUSION: We have concluded that the level of neuropeptide Y in plasma is increased in women with eclampsia and preeclampsia. Elevated plasma neuropeptide Y levels may play a key role in the development of eclampsia and preeclampsia.

Adult↗
PubMed2000

Prevention of collagen-induced arthritis in DBA/1 mice by oral administration of AZ-9, a bacterial polysaccharide from Klebsiella oxytoca.

Collagen-induced arthritis (CIA) is an excellent model of rheumatoid arthritis (RA) in humans that is induced in DBA/1 mice immunized with bovine type II collagen (CII). Here, we report that the induction of CIA was effectively suppressed by oral administration of AZ-9, a purified polysaccharide with the average molecular weight of approximately 200 kDa that was produced by a soil bacterium, Klebsiella oxytoca. When AZ-9 was administered at 125-250 mg/kg/day orally for 9 consecutive days after immunization with CII followed by its administration every 3 days, resulted in a marked reduction of the incidence and the severity of CIA. The serum level of anti-CII IgG2a and the production of IFN-gamma and IL-12 in the draining lymph node (LN) cells were significantly lower in AZ-9-administered mice than the untreated control. These findings suggest that orally administered AZ-9 suppressed CIA through attenuating a Th1-type response to CII. AZ-9 could be fragmented into smaller molecules (3-4 kDa) without losing its suppressive activity.

Administration, Oral↗
PubMed2000

Selective augmenting effects of nitric oxide on antigen-specific IgE response in mice.

Here, we report the enhancing effects of nitric oxide (NO) on an IgE antibody response in mice. Anti-trinitrophenyl (TNP) IgE production induced in vitro in TNP keyhole limpet hemocyanin (KLH)-primed spleen cells was inhibited by approximately 70% when an NO synthase (NOS) inhibitor, L-N(G)-monomethyl-L-arginine, was added at 10(-7)-10(-6) M to the lymphocyte culture. On the other hand, addition of NO-generating agents to the culture resulted in a marked enhancement of the IgE production. In contrast, anti-TNP IgM and IgG1 responses were affected only marginally when the IgE production was either suppressed or augmented by these agents. NO did not directly augment IgE class switching in normal B cells stimulated with lipopolysaccharide and interleukin (IL)-4. NO-mediated augmentation of the IgE response is considered to be of a physiological significance because administration of aminoguanidine (AG), an inhibitor of inducible NOS, to immunized mice resulted in a preferential suppression of anti-TNP IgE production in vivo. This may be explained by the observation that AG-administration increased interferon-gamma expression without changing that of IL-4 in the immunized mice. Taken together, these observations suggest a pathophysiological role of NO in the development of IgE-mediated allergic diseases.

Animals↗
PubMed2000

Prenatal and peripartum management of congenital afibrinogenaemia.

We experienced three cases and four successful deliveries with congenital afibrinogenaemia and propose the following guidelines for the prenatal and peripartum management: (i) genital bleeding usually begins at 5 weeks' gestation and spontaneous abortion always occurs at 6-8 weeks' gestation without fibrinogen infusion; (ii) the fibrinogen level must be at least 0.60 g/l and, if possible, higher than 1.0 g/l during the pregnancy; (iii) the necessary amounts of fibrinogen increase as the pregnancy progresses and the preterm labour occurs; (iv) the fibrinogen level under the continuous infusion of fibrinogen during labour must be at least 1.5 g/l and, if possible, higher than 2.0 g/l to prevent placental abruption; (v) the puerperium is usually uneventful with a reduced dose of fibrinogen infusion.

Abortion, Spontaneous↗
PubMed2000

p57(Kip2) regulates the proper development of labyrinthine and spongiotrophoblasts.

The cyclin-dependent kinase (cdk) inhibitor, p57 (Kip2) is a tumour suppressor candidate and a paternally-imprinted gene. In humans, the p57(Kip2) gene is located on chromosome 11p15.5, a region implicated in both sporadic cancers and Beckwith-Wiedemann syndrome. From analysis of p57(Kip2)-deficient mice, we demonstrate the relationship between trophoblastic abnormalities and p57(Kip2). Both p57(Kip2) null ((-/-)) embryos and heterozygous embryos with a maternally-derived mutated allele ((+*/-)) displayed placentomegaly, as well as dysplasia of labyrinthine and spongiotrophoblasts. The number of labyrinthine trophoblasts of homozygous embryos was twice that in wild-type embryos. When we measured kinase activities of cdk in total placenta lysates by the immuno complex kinase assay, there were no differences among the genotypes. These results show that p57(Kip2) may function in the proper development of labyrinthine and spongiotrophoblasts by pathways that are not involved with regulation of cdk activities. It is, therefore, suggested that p57(Kip2) protein might have an unknown role.

Animals↗
PubMed2000

An n-alkane-responsive promoter element found in the gene encoding the peroxisomal protein of Candida tropicalis does not contain a C(6) zinc cluster DNA-binding motif.

When an asporogenic diploid yeast, Candida tropicalis, is cultivated on n-alkane, the expression of the genes encoding enzymes of the peroxisomal beta-oxidation pathway is highly induced. An upstream activation sequence (UAS) which can induce transcription in response to n-alkane (UAS(ALK)) was identified on the promoter region of the peroxisomal 3-ketoacyl coenzyme A (CoA) thiolase gene of C. tropicalis (CT-T3A). The 29-bp region (from -289 to -261) present upstream of the TATA sequence was sufficient to induce n-alkane-dependent expression of a reporter gene. Besides n-alkane, UAS(ALK)-dependent gene expression also occurred in the cells grown on oleic acid. Several kinds of mutant UAS(ALK) were constructed and tested for their UAS activity. It was clarified that the important nucleotides for UAS(ALK) activity were located within 10-bp region from -273 to -264 (5'-TCCTGCACAC-3'). This region did not contain a CGG triplet and therefore differed from the sequence of the oleate-response element (ORE), which is a UAS found on the promoter region of 3-ketoacyl-CoA thiolase gene of Saccharomyces cerevisiae. Similar sequences to UAS(ALK) were also found on several peroxisomal enzyme-encoding genes of C. tropicalis.

Acetyl-CoA C-Acyltransferase↗
PubMed2000

Immunohistochemical study of annexin V expression in placentae of preeclampsia.

We investigated the clinical significance of annexin V in the placentae with preeclampsia and found: (1) annexin V was detected on trophoblasts in the placentae and the staining intensity of annexin V in the placentae from such patients was reduced when compared to normal placentae; (2) as expression of annexin V was reduced, the gestosis index from patients with preeclampsia was elevated and the standard deviation value in the infant's standard weight was decreased; plasma level of the fibrin degradation products and thrombin-antithrombin III complex from patients were elevated as the expression of anexin V was reduced. These results suggest that the reduced expression of annexin V in the placentae from patients with preeclampsia may lead to a hypercoagulable state in the intervillous space and may be associated with the development of intrauterine growth restriction.

Annexin A5↗
PubMed2000

Genetic evaluation of peroxisomal and cytosolic acetoacetyl-CoA thiolase isozymes in n-alkane-assimilating diploid yeast, Candida tropicalis.

The n-alkane-assimilating diploid yeast, Candida tropicalis, possesses two acetoacetyl-CoA thiolase (Thiolase I) isozymes encoded by one allele: peroxisomal and cytosolic Thiolase Is encoded by both CT-T1A and CT-T1B. To clarify the function of peroxisomal and cytosolic Thiolase Is, the site-directed mutation leading Thiolase I delta C6 without a putative C-terminal peroxisomal targeting signal was introduced on CT-T1A locus in the ct-t1b delta-null mutant. The C-terminus-truncated Thiolase I was active and solely present in the cytosol. Although the ct-t1a delta/t1b delta-null mutants showed mevalonate auxotrophy, the mutants having the C-terminus-truncated Thiolase I did not require mevalonate for growth, as did the strains having cytosolic Thiolase I. These results demonstrate that the presence of Thiolase I in the cytoplasm is indispensable for the sterol synthesis in this yeast. It is of greater interest that peroxisomal and cytosolic Thiolase I isozymes, products of the same genes, play different roles in the respective compartments, although further investigations will be necessary to analyze how to be sorted into peroxisomes and the cytosol.

Acetyl-CoA C-Acetyltransferase↗
PubMed1999

Biochemical characterization and expression analysis of neural thrombospondin-1-like proteins NELL1 and NELL2.

Two closely related genes coding for NELL proteins (NELL1 and NELL2) have been cloned by the yeast two-hybrid screening of a rat brain cDNA library with the regulatory domain of protein kinase C betaI (PKCbetaI) as bait. The rat NELL proteins show about 55% identity with each other and contain several protein motifs assigned to a secretion signal peptide, an NH(2)-terminal thrombospondin-1 (TSP-1)-like module, five von Willebrand factor C domains, and six epidermal growth factor-like domains; the NELL proteins share many protein motifs with TSP-1. The NELL proteins expressed in COS-7 cells are homotrimeric glycoproteins and possess heparin-binding activity. Furthermore, while NELL1 and NELL2 show distinct subcellular localization in cytoplasm, they both are partially secreted into the culture medium of COS-7 cells. Although the NELL1 mRNA is faintly expressed in adult neural cells, the NELL2 mRNA is expressed abundantly, particularly in the pyramidal cells of rat hippocampus, showing neuronal high plasticity. During mouse embryogenesis, expression of the NELL2 mRNA is initiated 7-11 days postcoitum, simultaneously with neural plate formation. These results strongly suggest that the NELL2 protein, similar to but not identical with TSP-1, is involved in the growth and differentiation of neural cells. Additionally, the NELL1 and NELL2 mRNAs were found to be expressed abundantly in Burkitt's lymphoma Raji cells and colorectal adenocarcinoma SW480 cells, respectively. Thus, it is likely that the NELL proteins also participate in the growth, differentiation, and oncogenesis of cancer cell lines.

Amino Acid Sequence↗
PubMed1999

Induction of preeclampsia like phenomena by stimulation of sympathetic nerve with cold and fasting stress.

The purpose of this study was to examine the effect of cold-stress, fasting stress and cold plus fasting stress on the sympathetic nerve activity. Pregnant and nonpregnant rats were kept in cold environment (0 degrees C), or fasting condition (12 h), and cold plus fasting condition for 2 weeks. Their plasma corticotrophin releasing factor (CRF), catecholamines, insulin levels, and platelets were measured, and histological examinations were performed. In cold plus fasting stress rats, a significant increased CRF, epinephrine (E), norepinephrine (NE), and insulin levels with decreased platelet count (P<0.0001) were observed compared with control. Histological study revealed that diffused enlarged glomeruli with fibrin deposition in the kidney, hemostasis, ischemic necrosis and fibrin deposition in liver and swelling along with hemorrhagic necrosis in adrenal gland of cold plus fasting stress rats. The biochemical and histological changes in cold plus fasting, cold-stressed or fasting rats were similar to human preeclampsia. The findings observed in cold plus fasting stress rats were more pronounced either than cold-stressed or fasting group. These results demonstrate that cold plus fasting stress is an intense stimulator of sympathetic nervous system than either cold stress or fasting.

Adrenal Glands↗
PubMed1999

The impact of vasoactive peptides on nitric oxide production in cultured sympathetic neurons.

The concentration of nitric oxide was found to be decreased in a hypersympathetic condition. We carried out experiments on cultured sympathetic neurons from 12-14-days-old chick embryos to investigate the role of vasoactive peptides and amine on nitric oxide production. Stimulation of cultured neurons with endothelin-1, norepinephrine and angiotensin-II initially increases nitric oxide production and subsequently decreases it in a dose-dependent manner (P<0.05, n = 7). Stimulation of Fura-2 acetoxymethyl ester-loaded neurons with endothelin-1, norepinephrine and angiotensin-II increases the calcium influx (within 30-90 s) and it is then restored to the initial level (P<0.05, n = 7). An additional observation was that specific stimulator L-arginine significantly increases the nitric oxide release and calcium influx into the cells, whereas N(W)-nitro-L-arginine methyl ester blunts nitric oxide release dose dependently (P<0.05, n = 7) and does not change the calcium concentration in the cells. We propose that vasoactive peptides and amines inhibit nitric oxide production in the cultured sympathetic neuron by regulation of intracellular calcium concentration.

Angiotensin II↗
PubMed1999

Chronic local cold stress to the soles induces hypertension in rats.

The purpose of this study was to determine whether cold-stress stimulation to the soles of paws produces continuous hypertension in rats. Wistar-Kyoto rats were kept in cages with a 0 degrees C floor and 23 degrees C room temperature (cold-stressed group, n = 10) or in cages with 23 degrees C floor and 23 degrees C room temperature (control group, n = 10). BP and levels of plasma catecholamines, serum glucose, and serum insulin were measured, and the histologic characteristics of the kidney and adrenal gland were studied in all groups. After a week of localized cold-stress, BP of the experimental rats were significantly increased over those of the control rats. Significant increases were also seen in plasma epinephrine and norepinephrine, as well as serum insulin concentrations in the rats that underwent localized cold stimulation; these changes were not observed in the control rats. Fibrinoid deposition in the kidney and the intensity of neuropeptide Y-staining in the adrenal medulla were increased in the localized cold-stressed group compared with the control group. We conclude that chronic local cold stimulation to the soles is a new model of experimental hypertension.

Adrenal Glands↗
PubMed1999

Construction of an autonomously replicating plasmid in n-alkane-assimilating yeast, Candida tropicalis.

A transformation system using the autonomously replicating plasmid in the n-alkane-assimilating and asporogenic diploid yeast, Candida tropicalis, was developed. For the cloning of a DNA fragment containing a potential autonomously replicating sequence (ARS) from the genomic DNA of C. tropicalis, the ura3 mutant obtained using ethylmethane sulfonate as the host and the URA3 gene amplified by PCR using the C. tropicalis genomic DNA as a selectable marker were prepared. Comparison of ARSs among yeasts revealed that the consensus sequence found in S. cerevisiae was also present in C. tropicalis. The autonomously replicating plasmid containing the putative ARS as the shuttle vector, capable of replicating in both E. coli and C. tropicalis, was first constructed. The transformation system using this plasmid, in addition to the integrative transformation system, will be applicable to genetic studies of C. tropicalis.

Journal Article↗
PubMed1999

A new treatment of severe pre-eclampsia by long-term epidural anaesthesia.

We hypothesised that long term epidural anaesthesia suppresses sympathetic overactivity in pre-eclampsia. Two equal groups of severe pre-eclamptic patients were treated either with long-term epidural anaesthesia (epidural group) or bed rest, diet control, and an antihypertensive drug (control group). After 7 days of epidural block, mean arterial blood pressures decreased, platelet count and serum total protein increased in all cases while proteinuria decreased in four cases. All patients treated with a long-term epidural therapy continued their pregnancies for more than 3 weeks after admission. The infants in the epidural group had 1-min Apgar scores above 8, a body weight of 2240+/-310 g (mean +/- s.d.) and normal neonatal progress. In contrast, the pregnancies of eight patients in the control group were terminated within 2 weeks of admission due to severe pre-eclampsia or foetal distress, the birth weight of the infants was 1590+/-380 g (mean +/- s.d.) and four had neonatal distress. Progressive worsening in the mean arterial pressure, proteinuria, platelet count and serum total protein was found in these patients. Long-term epidural anaesthesia suppresses the sympathetic hyperactivity and thus improves pre-eclamptic condition which may open a new treatment in case of progressive severe pre-eclampsia.

Adult↗
PubMed1999

Annexin V inhibits phosphatidylserine-induced intrauterine growth restriction in mice.

To investigate the role of phosphatidylserine (PS) derived from the activated platelets in placental circulation, we established an artificial PS-induced intrauterine growth restriction (IUGR) model in mice and examined whether annexin V, a PS-binding anticoagulant protein, could prevent the development of IUGR in the animal experiments. The ICR mice were injected in the tail vein on days 8, 11 and 14 of pregnancy with filtered PS/phosphatidylcholine (PC) microvesicles (<0.3 microm in maximal diameter). The microvesicles have a procoagulant activity which was inhibited by annexin V in a dose-dependent fashion. The mice were killed on day 18 of pregnancy and the placental and fetal weights were measured. The placental tissue specimens were examined microscopically. PS/PC vesicles induced significant reductions in fetal weights compared with PC vesicles alone. The placental tissue revealed severe congestion with fibrin depositions although the lung and kidney tissue specimens showed minimal histological changes. PS/PC microvesicles with recombinant annexin V showed no significant reductions in fetal weights in mice with PS/PC vesicles alone. These results suggest that PS from the activated platelets induces IUGR by enhancing the coagulation cascade in the placental circulation and that annexin V from the villous trophoblast prevents the development of IUGR.

Animals↗
PubMed1999

Coagulation/fibrinolysis disorder in patients with severe preeclampsia.

We investigated coagulation/fibrinolysis parameters in 50 patients with severe preeclampsia. The coagulation and clinical indices in patients with severe preeclampsia were 1.595 and 1.414, respectively. These indices show a strong correlation between the clinical status and coagulation/fibrinolysis abnormalities. Among patients with severe preeclampsia, a significant decrease in antithrombin (AT) (p = 0.002) and a significant increase in plasmin inhibitor complex (PIC) (p = 0.002), D-dimer (p < 0.05), and thrombin-antithrombin complex (TAT) (p = 0.001) were observed in cases terminated by cesarean section compared with those cases of vaginal delivery. There was no significant difference in platelet count (Plt), however, deltaPlt (the difference between platelet counts in early gestation and before delivery) was significantly larger (p < 0.05) in cases that ended in cesarean section. Furthermore, among cases terminated by cesarean section, a significant increase in PIC (p < 0.01) was observed when pregnancies were terminated because of maternal factors compared with those terminated because of fetal factors. These results suggest that (1) even in patients with severe preeclampsia, vaginal deliveries can be successful when they display a less hypercoagulable state; (2) a decrease in Plt during pregnancy may be a predictive marker for the termination of pregnancy; and (3) an excessive hypercoagulable state in patients with severe preeclampsia may be associated with the termination of pregnancy, especially when there is an aggravation of maternal factors.

Adult↗