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H Kitagawa

Publications and source records attributed to H Kitagawa.

At least 199 records · Page 11Linked to original sources
PubMed1996

Elevation of either axoplasmic norepinephrine or sodium level induced release of norepinephrine from cardiac sympathetic nerve terminals.

Using dialysis technique, prominent accumulation of norepinephrine (NE) in the myocardial interstitial space was observed under two different conditions: (1) local administration of a monoamine oxidase inhibitor (pargyline, 1, 10 mM), (2) local administration of a Na, K-ATPase inhibitor (ouabain, 10, 100 microM). Further, pretreatment with a vesicle uptake inhibitor (reserpine, 10 microM) augmented these responses. Either condition independently caused endogenous NE release and a brisk increase in dialysate NE levels might occur as a consequence of non-exocytotic release of NE.

Animals↗
PubMed1996

The burst firing in the layer III and V pyramidal neurons of the cat sensorimotor cortex in vitro.

We identified the burst and single-spiking cells, and the repetitive bursting cells in layers III and V of the cat sensorimotor cortex with intracellular recording and staining techniques. Both types of the bursting cells were found in 22.7% of the recorded layer V neurons and in 23.1% of the recorded neurons in layer III. The bursting cells were characterized by the prominent afterdepolarization (ADP) which was usually reaching the threshold depolarization. Intracellular staining revealed that the morphology of the bursting cells was not so different from that of the regular-spiking cells in the cat.

Adenosine Diphosphate↗
PubMed1996

Direct and indirect activation of human corticospinal neurons by transcranial magnetic and electrical stimulation.

Corticospinal volleys and surface electromyographic (EMG) responses evoked by magnetic and electrical transcranial stimulation were recorded simultaneously in three conscious human subjects. For magnetic stimulation, the figure-of-eight coil was held on the hand motor area either with the induced current through the brain flowing in a postero-anterior direction (P-A stimulation) or in a latero-medial direction (L-M stimulation). For electrical stimulation, the anode was placed 7 cm lateral to the vertex and cathode at the vertex (anodal stimulation). The P-A stimulation that was generally used preferentially evoked I waves, whereas the L-M and anodal stimulation preferentially evoked D wave. The results suggested that the mode of activation by transcranial magnetic stimulation altered, depending on its current direction, and the difference between P-M magnetic and electrical stimulation can be explained by the context of the D and I hypothesis.

Aged↗
PubMed1996

Molecular cloning of a developmentally regulated N-acetylgalactosamine alpha2,6-sialyltransferase specific for sialylated glycoconjugates.

A cDNA encoding a novel sialyltransferase has been isolated employing the polymerase chain reaction using degenerate primers to conserved regions of the sialylmotif that is present in all eukaryotic members of the sialyltransferase gene family examined to date. The cDNA sequence revealed an open reading frame coding for 305 amino acids, making it the shortest sialyltransferase cloned to date. This open reading frame predicts all the characteristic structural features of other sialyltransferases including a type II membrane protein topology and both sialylmotifs, one centrally located and the second in the carboxyl-terminal portion of the cDNA. When compared with all other sialyltransferase cDNAs, the predicted amino acid sequence displays the lowest homology in the sialyltransferase gene family. Northern analysis shows this sialyltransferase to be developmentally regulated in brain with expression persisting through adulthood in spleen, kidney, and lung. Stable transfection of the full-length cDNA in the human kidney carcinoma cell line 293 produced an active sialyltransferase with marked specificity for the sialoside, Neu5Ac-alpha2,3Gal-beta1,3GalNAc and glycoconjugates carrying the same sequence such as G(M1b) and fetuin. The disialylated tetrasaccharide formed by reacting the sialyltransferase with the aforementioned sialoside was analyzed by one- and two-dimensional 1H and 13C NMR spectroscopy and was shown to be the Neu5Ac-alpha2,3Gal-beta1,3(Neu5Ac-alpha2,6)GalNAc sialoside. This indicates that the enzyme is a GalNAc alpha-2,6-sialyltransferase. Since two other ST6GalNAc sialyltransferase cDNAs have been isolated, this sialyltransferase has been designated ST6GalNAc III. Of these three, ST6GalNAc III displays the most restricted acceptor specificity and is the only sialyltransferase cloned to date capable of forming the developmentally regulated ganglioside G(D1alpha) from G(M1b).

Amino Acid Sequence↗
PubMed1996

Developmental changes in serum UDP-GlcA:chondroitin glucuronyltransferase activity.

Bovine, rat, and chicken UDP-GlcA:chondroitin glucuronyltransferase activities in sera during prenatal and postnatal development were systematically measured with polymeric chondroitin as an exogenous acceptor and with UDP-[14C]GlcA as a donor. The results indicated that the activity changed markedly with development in all species examined. Specifically, the activity was the highest at the middle prenatal stage in the bovine and chicken sera and at the late prenatal stage in the rat serum, and it decreased sharply thereafter in all three species. Although the origin of the serum enzyme has not yet been determined, these changes may reflect developmentally regulated biosynthesis of chondroitin sulfate and also suggest that the glucuronyltransferase could be a regulatory enzyme controlling the expression of chondroitin sulfate.

Animals↗
PubMed1996

Genomic organization and chromosomal mapping of the Gal beta 1,3GalNAc/Gal beta 1,4GlcNAc alpha 2,3-sialyltransferase.

In this report we describe the chromosome mapping and genomic organization of the human Gal beta 1,3GalNAc/Gal beta 1,4GlcNAc alpha 2,3-sialyltransferase gene. The gene is localized to human chromosome 11(q23-q24) by in situ hybridization of metaphase chromosomes. It spans more than 25 kilobases of human genomic DNA and is distributed over 14 exons that range in size from 61 to 679 base pairs. Previous characterization of cDNAs encoding the Gal beta 1,3GalNAc/Gal beta 1,4GlcNAc alpha 2,3-sialyltransferase revealed that the gene produces at least three transcripts in human placenta, which code for identical protein sequences except at the 5' ends (Kitagawa, H., and Paulson, J. C. (1994a) J. Biol. Chem. 269, 1394-1401). Repeated screening for clones that contain the 5' end of the cDNA has identified two additional distinct mRNAs that are expressed in human placenta. Comparison of the genomic DNA sequence with that of the five different mRNAs indicates that these transcripts are produced by a combination of alternative splicing and alternative promoter utilization. Northern analysis indicated that one of them is specifically expressed in placenta, testis, and ovary, indicating that its expression is independently regulated from the others.

Alternative Splicing↗
PubMed1996

Prostaglandin E2 production by endogenous secretion of interleukin-1 in decidual cells obtained before and after the labor.

Previous reports revealed that interleukin-1 (IL-1) was involved in the process of premature labor in the cases with intrauterine infection. However, the roles of the cytokine in normal spontaneous labor remain uncertain. The present studies aimed at determining the involvement of the cytokine in prostaglandin (PG)E2 production during labor by the third trimester decidual cells. The cells were obtained at the time of normal spontaneous delivery (NVD) and elective cesarean section (ECS). The NVD cells produced significantly more amount of PGE2 than the ECS cells and the both cells responded to the addition of IL-1 beta to increase PGE2 production. A specific inhibitor of cyclooxygenase-2 (COX-2), NS398, decreased basal PGE2 production and inhibited the stimulatory effect of IL-1 beta in a dose dependent manner in NVD cells. The NVD cells secreted more amount of IL-1 beta than the ECS cells and contained more amount of preprocessed 31kD IL-1 beta inside the cells. The addition of recombinant soluble human IL-1 receptor (type I) not only blocked the effect of IL-1 beta on PG secretion, but significantly reduced the basal production of PGE2 by NVD cells. These results indicate that decidual PG production depends upon COX-2 after the onset of labor. Besides it seems likely that endogenously produced IL-1 beta may be involved in autocrine or paracrine fashion in inducing COX-2 after the onset of labor.

Blotting, Western↗
PubMed1996

Expression of 16 kDa proteolipid of vacuolar-type H(+)-ATPase in human pancreatic cancer.

Recent studies have shown that bafilomycin A1-sensitive vacuolar-type H(+)-ATPase (V-ATPase) plays important roles in cell growth and differentiation. However, there is no published study that has focused on the expression of V-ATPase in human tumour tissues. This study was designed to examine the mRNA and protein levels for the 16 kilodalton (kDa) proteolipid of V-ATPase in human pancreatic carcinoma tissues. We first investigated the mRNA level for V-ATPase in six cases of invasive pancreatic cancers and two normal pancreases, using reverse transcription-polymerase chain reaction technique. Then, we examined immunohistochemically the level of V-ATPase protein in 49 pancreatic cancers and ten benign cystic neoplasms of the pancreas, using antisera raised against the 16 kDa proteolipid. There was a notable difference in the level of V-ATPase mRNA between normal and pancreatic carcinoma tissues, with no evident difference in the expression of the beta-actin gene. Immunohistochemically, 42 out of 46 invasive ductal cancers (92%) displayed a mild to marked immunoreactivity for V-ATPase in the cytoplasm, whereas neither non-invasive ductal cancers nor benign cystic neoplasms expressed detectable immunoreactive proteins. These findings suggest that the overexpression of V-ATPase protein is characteristic of invasive pancreatic tumours. V-ATPase may play some crucial roles in tumour progression.

Adenocarcinoma↗
PubMed1996

Inhibition of 5-lipoxygenase promotes the regeneration of the liver after partial hepatectomy in normal and icteric rats.

The role of leukotriene (LT) on liver regeneration after hepatectomy is still unknown. LTB4 stagnates in the liver with obstructive jaundice, because LTB4 is excreted in the bile; therefore, LTB4 may have an effect on liver regeneration after hepatectomy with obstructive jaundice. Release of obstructive jaundice and simultaneous 70% hepatectomy was performed in rats to study the effect of 5-lipoxygenase inhibitor (AA-861) on liver regeneration. Group 1 underwent hepatectomy with administration of 0.1 mL dimethyl sulfoxide (DMSO), group 2 underwent hepatectomy with administration of AA-861 (20 mg/kg/d) dissolved in 0.1 mL DMSO, group 3 underwent hepatectomy with administration of AA-861 (40 mg/kg/d) dissolved in 0.1 mL DMSO, group 4 underwent release of obstructive jaundice and hepatectomy with administration of 0.1 mL DMSO, and group 5 underwent relief of obstructive jaundice and hepatectomy with administration of AA-861 (20 mg/kg/d). DMSO or AA-861 was administered 24 hours before, during, and 24 hours after hepatectomy in each group. Whole blood LTB4 and serum alanine aminotransferase (ALT), total bilirubin, and bromodeoxyuridine labeling index (LI) were measured before and after hepatectomy. The LTB4 level increased during obstructive jaundice and after hepatectomy. LTB4 and serum ALT levels were significantly lower after hepatectomy in the rats that were administered AA-861, and a significantly higher LI was observed at 24 hours after hepatectomy in rats receiving AA-861. Inhibition of 5-lipoxygenase promotes liver regeneration and decreases hepatocyte injury after hepatectomy associated with obstructive jaundice.

Alanine Transaminase↗
PubMed1996

Gestational changes in nitric oxide synthase activity in the rat placenta.

OBJECTIVE: To assess the importance of nitric oxide (NO) generated in the placenta on pregnancy, nitric oxide synthase (NOS) activities were measured in the rat placentas of different gestational ages. MATERIALS AND METHODS: NOS activity was determined by [3H] L-arginine to [3H]-citrulline conversion assay on rat placenta of day 5, 10, 15 and 21 of gestation. RESULTS: NOS activity distributed both in the soluble and particulate fractions. Inhibition of NOS activity by L-arginine analogs confirmed the substrate specificity. The requirement of calcium/calmodulin for the maximal activity indicated that the rat placenta NOS was of a constitutive calcium/calmodulin dependent isoform. The activities in both fractions were higher in the earlier gestational age placentas, decreasing with progression of gestation, and the lowest in the term placentas. CONCLUSION: Although NOS activity was detected in the placenta throughout gestation, it was highest in the early gestational age placenta, suggesting a possible significant role of NO in early gestation.

Animals↗
PubMed1996

Effect of substrate on indirect immunofluorescence test for canine pemphigus foliaceus.

The effect of substrate on indirect immunofluorescence (IIF) tests for the detection of circulating autoantibodies was studied by examining sera from 14 canine pemphigus foliaceus patients, six sera with non-pemphigus dermatoses and ten normal dog sera against five different substrates from three species. These substrates included bovine esophagus, bovine nose, bovine tongue, monkey esophagus, and canine nose skin. Nine out of 14 (64.3%) sera from patients with canine pemphigus foliaceus showed intercellular space staining by indirect immunofluorescence using bovine esophagus as substrate. However, sera from nonpemphigus dermatoses and normal dog did not react with bovine esophagus. In other substrates, only bovine tongue showed 1/8 (12.5%) positive reaction at the intercellular space by sera from canine pemphigus foliaceus. Dog nose skin showed the intercellular space staining against ten of ten (100%) normal dog serum. Monkey esophagus showed the fluorescent deposit at the intercellular space in four of nine (44.4%) of pemphigus foliacues dog sera, however, four of ten (40%) of normal dog sera revealed nonspecificity intercellular staining. These results indicate that the sensitivity and the specifity of IIF test in canine pemphigus foliaceus depend on the substrate. The best substrate for detecting circulating autoantibody in canine pemphigus foliaceus patients among five different substrates was bovine esophagus because of its sensitivity and high specificity. The diagnosis of canine pemphigus foliaceus should be made on the basis of a combination of clinical signs, histopathology, direct immunofluorescence, and the detection of circulating autoantibody.

Animals↗
PubMed1996

Attenuation of human chorionic gonadotropin release by nitric oxide in choriocarcinoma cell lines.

Nitric oxide (NO) is involved in the regulation of endocrine functions, but only a few studies have been reported about its role in placental hormone secretion. We investigated whether NO has any function in the release of human chorionic gonadotropin (hCG) in two different choriocarcinoma cell lines, JEG-3 and BeWo. First, nitric oxide synthase (NOS) was characterized in the choriocarcinoma cells. NOS activity was localized mainly in the particulate fraction and depended on calcium/calmodulin. Activity was inhibited by the presence of the L-arginine analog, NG-monomethyl-L-arginine (L-NMMA; 1 x 10(-4) M). Western blot analysis showed that the choriocarcinoma cells contained an endothelial isoform of NOS. The NO donor, sodium nitroprusside (SNP; 1 x 10(-5) and 1 x 10(-4) M), significantly inhibited hCG secretion in both choriocarcinoma cell lines. The suppression of hCG release by SNP (1 x 10(-5) M) was blocked by the addition of an NO scavenger, hemoglobin (1 x 10(-6) M). L-Arginine (1 x 10(-2) M), a NOS substrate, inhibited basal hCG secretion in JEG-3 cells. Incubation of the cells with L-NMMA (1 x 10(-4) and 1 x 10(-3) M) significantly increased hCG release. Exposure of both cell lines to increasing concentrations of a cyclic GMP analog (8-bromo-cyclic GMP; 1 x 10(-4) to 1 x 10(-2) M) caused a dose-dependent inhibition of hCG release. Cyclic GMP accumulation in response to SNP (1 x 10(-4) M), however, was not detected in either JEG-3 or BeWo cells. These data demonstrated that the endothelial isoform of NOS and a functional L-arginine-NO pathway are present in the choriocarcinoma cell lines. In addition, these findings support the hypothesis that NO produced in these cell lines is involved in the regulation of hCG secretion. We assume that although cyclic GMP is likely to play a role as a second messenger, a cyclic GMP-independent pathway cannot be excluded as a possible physiological mechanism in the attenuation of hCG release by NO.

8-Bromo Cyclic Adenosine Monophosphate↗
PubMed1996

The innervation of the chromaffin cells in the head kidney of the carp, Cyprinus carpio; regional differences of the connections between nerve endings and chromaffin cells.

Nerve fibres and their connections with chromaffin cells in the carp head kidney were studied by light and electron microscopy. Some nerve bundles entered the head kidney from the dorsal aspect along veins. Many unmyelinated axons emerged from the nerve bundles to invade the clusters of chromaffin cells, the distribution of which was restricted to the neighbourhood of the venous trunks and their tributaries. Most of the nerve endings were attached to a chromaffin cell by synaptic junctions and were generally invaginated into the cell. Some nerve endings were flattened in shape and connected with two chromaffin cells. Occasional exocytotic figures of synaptic vesicles opening into the intercellular space, or synaptic junctions along the course of the nerve fibre were observed. The percentage of the chromaffin cells supplied by nerve endings in the head kidney as a whole was similar to that in primitive amphibians. The distribution of the chromaffin cells and the frequency of their innervation suggest that carp chromaffin cells are phylogenetically similar to those of amphibians. The frequencies of synaptic connections in the carp head kidney showed regional differences. The number in dorsal portion was significantly higher than that in two ventral portions. It is suggested that chromaffin cells in the head kidney are separable into two populations: one (in the dorsal portion) shows closer and the other (in the ventral portions) less contact with nerve fibres. The fine structure of the nerve endings indicates that catecholamine secretion of carp chromaffin cells is partially modulated by nerve fibres (probably preganglionic cholinergic fibres). However, the low frequency of synaptic connections on the chromaffin cells and their distribution suggest that carp chromaffin cells are mainly modulated by the endocrine system via the bloodstream.

Animals↗
PubMed1996

[A reused suction catheter was broken and produced a tracheobronchial foreign body].

We present a rare case involving a broken suction catheter that became lodged in the tracheobronchial tree. An eight-month-old infant was scheduled for hernioplasty. Following intubation with a 4 French (Fr.) endotracheal tube, a 5 Fr. reused suction catheter was applied for suctioning a moderate amount of secretion. This catheter had been resterilized by ethylene oxide gas (EOG). Insertion of the catheter into the tube was not done smoothly, and we could not obtain any secretion. During the extraction of the suction catheter by force, the catheter broke. The distal fragment (20 cm length) seemed to have been lodged in the tracheobronchial tree. Prior to its removal by bronchoscopy, the endotracheal tube was extubated. Fortunately the remaining part of the catheter come out with the tube. Ten cm of the fractured catheter was included in the tube and 5 cm protruded from the tube. The catheter of smaller diameter is easy to be broken even by weaker force. After resterilization by EOG for once, there was no change in length and force at breaking point. Elongation of the broken catheter (85.5%) was less compared with the new sample (155%). At the breaking point, half of the cross section was very smooth and looked as if it had been cut by a razor, while the other half appeared to have been broken by pulling. The break may have started from the crack which had occurred at the insertion or resterilization. Therefore, we should restrict the reuse of small suction catheters, and should always utilize the catheter of the largest size possible.

Anesthesia, Inhalation↗
PubMed1996

Morphological studies of the hyalocytes in the chicken eye: scanning electron microscopy and inflammatory response after the intravitreous injection of carbon particles.

Hyalocytes in the pecten oculi and ciliary body of adult chickens and their response to Escherichia coli were investigated by transmission and scanning electron microscopy and the inflammatory response following the intravitreous injection of colloidal carbon examined by microscopy. In normal chickens, the hyalocytes were mainly found on the pleats of the pecten oculi and on the ciliary body. There were no hyalocytes on the retina. There is thus a close relationship between the vasculature in the tissues surrounding the vitreous chamber and the distribution of hyalocytes. The hyalocytes, which were predominantly spindle shaped or oval in contour, displayed a ruffled surface with occasional blebs, filopodia and lamellipodia. Flattened hyalocytes with relatively few and short pseudopodia were frequently observed, especially on the ciliary body. Hyalocytes responded quickly to E. coli bacteria which they phagocytosed. The response to colloidal carbon in the vitreous chamber had 3 distinct changes. In the 1st (2 d after carbon injection), the hyalocytes, the resident macrophages, actively ingested the carbon particles without significant leucocyte recruitment. In the 2nd stage (at 7-14 d), a large number of macrophages infiltrated the ciliary body and emigrated into the vitreous chamber. In the 3rd stage (at 30 d), the infiltration by macrophages into the ciliary body was complete. The carbon-laden macrophages disappeared from the vitreous body but accumulated on the pecten oculi and retina. They were exclusively drained through the scleral venous sinus in the iridocorneal angle.

Animals↗
PubMed1996

Cloning and high expression of rabbit FKBP25 in cornea.

Rabbit 25 kDa FK-506/rapamycin binding protein (FKBP25) cDNA was isolated during a screening of rabbit corneal endothelial cDNA library. The cDNA clone was a 955 bp fragment with a 670 bp open reading frame and a 285 bp 3' non-coding region. The cDNA and deduced amino acid sequences were 91.7 and 96.4% identical, respectively, to previously reported human FKBP25B sequences. The lysine-rich region KK(X)7KK(X)26KKKK, which plays an important role in nuclear translocation in rabbit FKBP25, was recognized. Reverse transcription-polymerase chain reaction (RT-PCR) amplification of rabbit FKBP25 and FKBP12 in selected rabbit organs, including total cornea, showed higher expressions in cornea, retina, cerebrum and cerebellum than other compared tissues. RT-PCR amplification in rabbit cultured corneal cells showed expressions in all cultured corneal epithelial, stromal, endothelial, and especially in SV40-adenovirus vector-immortalized epithelial cells. The higher expressions of FKBP25 and FKBP12 suggest significant roles for FKBPs in those tissues.

Amino Acid Sequence↗
PubMed1996

[A new strategy for the therapy of pancreatic cancer by proton pump inhibitor].

Bafilomycin A1 is a specific inhibitor of vacuolar type proton pump (V-ATPase). This study was designed to examine the effect of bafilomycin A1 on the growth of Capan-1 human pancreatic cells which overexpress V-ATPase. Nude mice bearing a xenografted tumor of Capan-1 cell line were treated for 4 weeks with bafilomycin A1 (1.0 mg/kg/day). This treatment inhibited tumor growth, which was significantly reduced as compared with controls after 21 days (p < 0.05). However, there were no significant differences in body weights between groups. Microscopically, a large number of tumor cells in the treated group showed signs of apoptosis. These findings suggest that apoptosis induced by bafilomycin A1 was the event involved in suppression of tumor growth in vivo.

Animals↗