Biomedical subjects

N Fujii

Publications and source records attributed to N Fujii.

At least 433 records · Page 24Linked to original sources

PubMed1989

Effect of synthetic physalaemin on splanchnic circulation in dogs.

Physalaemin has been reported as one of the most potent vasodilator and hypotensive peptides (1-4). In spite of these studies, however, the effect of the peptide on splanchnic circulation is not known precisely. In the present study, the effect of synthetic physalaemin on superior mesenteric arterial blood flow, portal venous blood flow and pancreatic capillary blood flow was investigated in dogs. Dose dependent increases of superior mesenteric arterial blood flow and portal venous blood flow were induced in response to physalaemin (0.1-10.0 ng/kg). Superior mesenteric arterial blood flow and portal venous blood flow attained maximal increases of 77 +/- 8.9% and 70 +/- 8.6%, respectively, at a dose of 5 ng/kg. Physalaemin caused a dose-related decrease in systemic arterial blood pressure. Pancreatic capillary blood flow did not show significant change with the administration of physalaemin. These data suggest that physalaemin may play some physiological roles in the regulation of splanchnic circulation.

Amino Acid Sequence↗

PubMed1989

Effects of human PTH-related peptide and human PTH on cyclic AMP production and cytosolic free calcium in an osteoblastic cell clone.

Recently, human parathyroid hormone-related peptide (hPTHrP) has been purified and its amino acid sequence determined. Within the amino-terminal 13 residues of hPTHrP, 8 amino acids were found homologous between hPTHrP and human PTH (hPTH). This peptide was reported to stimulate cyclic AMP (cAMP) production in osteoblastic cell lines (UMR106 and ROS17/2.8). However, whether or not this peptide affects another second messenger, i.e., cytosolic free calcium ([Ca2+]i), in osteoblasts has not yet been determined. Therefore, in the present study, we examined the effects of synthetic amino-terminal fragments of hPTHrP (Tyr40hPTHrP1-40 and hPTHrP1-34) on intracellular cAMP production and [Ca2+]i in an osteoblastic cell line (MC3T3-E1) and compared them with those of hPTH1-34. Human PTHrP1-34, Tyr40hPTHrP1-40 and hPTH1-34 stimulated cAMP production in an equipotent manner at concentrations ranging from 2.5 x 10(-10) to 1.3 x 10(-6) M. Human PTH1-34 at concentrations from 2.5 x 10(-7) to 1.3 x 10(-6) M significantly (P less than 0.05) increased [Ca2+]i, but hPTHrP1-34 and Tyr40hPTHrP1-40 at the same concentrations did not. These results suggest a different receptor-mediated mechanism for [Ca2+]i increase between hPTHrP and hPTH, although these two peptides appear to share the same receptor site(s) which is coupled to the cAMP system in MC3T3-E1.

Animals↗

PubMed1989

Regulation of serum glycosaminoglycan sulfotransferase activities: inhibition by sulfated glycosaminoglycans and activation by polyamines and basic peptides including a polylysine-containing segment of the c-Ki-ras 2 protein.

The regulatory mechanisms for the glycosaminoglycan sulfotransferases in fetal calf serum were investigated. The enzymes examined were those which transfer sulfate from 3'-phosphoadenosine 5'-phosphosulfate to 1) position 6 of the internal N-acetylgalactosamine units of chondroitin, 2) position 6 of galactose units of keratan sulfate, and 3) position 2 (an amino group) of glucosamine units of heparan sulfate. The former two enzymes were activated by spermidine, spermine, protamine, and poly L-lysine. All the enzymes were strongly inhibited by heparin and dextran sulfate, whereas only the chondroitin 6-O-sulfotransferase was inhibited by sulfated galactosaminoglycans. The inhibition of this enzyme by the sulfated glycosaminoglycans was abolished by polylysine, indicating that the activation by polylysine is partly due to the neutralization of endogenous acidic inhibitors, including sulfated glycosaminoglycans. Affinity chromatographic studies demonstrated that heparin specifically binds to the three enzymes, which have anionic isoelectric points, and that chondroitin 6-sulfate, spermine, and polylysine bind to the former two enzymes under physiological conditions. Thus, the activation by spermine and polylysine as well as the inhibition by sulfated glycosaminoglycans also appears to occur through their binding to the enzymes. Studies with synthetic lysine oligomers and an affinity-purified (approximately 700-fold) fraction containing the former two enzymes indicated that the pentamer is the minimum unit required for the activation. A synthetic peptide, containing six consecutive lysines at the carboxy terminus of the human c-Ki-ras 2 protein, also regulated the two enzyme activities at micromolar concentrations. The possible physiological implications of the observed effects of these regulatory substances on the glycosaminoglycan sulfotransferases are discussed in relation to glycosaminoglycan synthesis during the proliferation, differentiation, and transformation of cells. The possibility of sulfated glycosaminoglycans being enzyme regulators is also discussed.

Animals↗

PubMed1989

Immuno-affinity purification of specific antibodies against human gastrin releasing peptide (h-GRP) by the h-GRP(1-8)-linked polydimethylacrylamide resin.

A new method for immuno-affinity purification of specific antibodies against human gastrin releasing peptide(h-GRP) was developed. The antiserum GP(No. 6201) elicited by h-GRP-BSA conjugate was heterogeneous and reacted not only with h-GRP and its fragments but also partially with other structurally related peptides, such as other GRPs (porcine, canine, and chicken), bombesin, and neuromedin-C. To obtain specific antibodies against human GRP, antiserum GP was purified by column chromatography on the amino-terminal octapeptide h-GRP(1-8)-linked polydimethylacrylamide resin. The antibody thus obtained was highly specific to amino-terminal sequence of h-GRP and hardly reacted with other GRPs (porcine, canine and chicken), bombesin, and even carboxy-terminal h-GRP fragments in ELISA.

Acrylamides↗

PubMed1989

Binding of Clostridium botulinum type C neurotoxin to different neuroblastoma cell lines.

Binding of type C neurotoxin (C1 toxin) from Clostridium botulinum (strain Stockholm) to neuroblastoma cell lines was studied by using biotinylated anti-toxin antibody and avidin-biotinylated peroxidase complex. The neurotoxin bound with high efficiency to mouse neuroblastoma (NS-20Y and NIE-115) cells and to hybridomas of rat glioblastoma and mouse neuroblastoma (NG108-C15) cells. The toxin bound little to human neuroblastoma, rat astrocytoma, and nonneural cell lines. Binding of the neurotoxin to NG108-C15 cells was inhibited by gangliosides (GT1b and GM1) and by monoclonal antibodies (CA-12 and C-9), although inhibition was not complete. Sequential preincubation of C1 toxin with GT1b and CA-12 caused complete inhibition. A Scatchard plot of binding of 125I-labeled C1 toxin to NG108-C15 cells showed a hyperbolic curve. Monoclonal antibody CA-12 but not C-9 neutralized the lethal activity of the toxin toward mice. Only C-9 clearly inhibited toxin binding to GT1b. These results suggest that NG108-C15 cells have at least two kinds of receptors for C1 toxin. From the results of binding tests with neuraminidase-, pronase-, and trypsin-treated NG108-C15 cells, the chemical nature of the high-affinity site was presumed to be a glycoprotein containing sialic acid. GT1b may have an important role in low-affinity sites.

Animals↗

PubMed1989

Studies on peptides. CLXVII. Solid-phase syntheses and immunological properties of fragment peptides related to human malaria circumsporozoite protein.

A glycine-linked tetramer of Asn-Ala-Asn-Pro, a tandem repeated sequence of malaria circumsporozoite (CS) protein, was synthesized by the Boc-based solid phase method, followed by deprotection with 1 M trimethylsilyl trifluoromethanesulfonate-thioanisole in trifluoroacetic acid. In addition, three tetramer-related peptides were similarly synthesized, i.e., a 34-residue peptide [linked with TH, a proposed T-cell epitope of CS, at the C-terminus of the tetramer], a 46-residue peptide and a 59-residue peptide [linked with HA or HA', two proposed T-cell epitopes of influenza hemagglutinin protein, at the N-terminus of the above 34-residue peptide]. Their immunological properties were examined by enzyme-linked immunosorbent assay, for which three different congenic strains of mouse were used to raise the specific antibodies. Despite conjugation of T-cell epitopes to the tetramer, the mice of low-responder strains to the tetramer failed to produce any antibody specific to the tetramer. However, with the aid of recombinant interleukin 2 as an adjuvant, the low-responder mice produced antibody with relatively high titers.

Antigens, Surface↗

PubMed1989

Immuno-affinity purification of specific antibodies against vasoactive intestinal polypeptide (VIP) on VIP (1-10)-linked polydimethylacrylamide resin.

A novel method for immuno-affinity purification of specific antibodies against amino-terminal (N-terminal) porcine vasoactive intestinal polypeptide (p-VIP) was developed. The antiserum VP (No. 6203) elicited by p-VIP-immunoglobulin G (IgG) conjugate was heterogenous and reacted not only with the N-terminal fragments of p-VIP but also with carboxy-terminal (C-terminal) fragments. To obtain specific antibodies against the N-terminal fragment of p-VIP, antiserum VP was purified by column chromatography on N-terminal decapeptide (p-VIP 1-10)-linked polydimethylacrylamide resin. The antibody thus obtained was highly specific to the N-terminal sequence of p-VIP and hardly reacted with the C-terminal fragments of VIP in enzyme-linked immunosorbent assay.

Antibodies↗

PubMed1989

1H-NMR studies of calmodulin: the character of the calcium binding sites.

The effects of various divalent cations on the Ca2+-binding sites of calmodulin were observed by 400 MHz 1H-NMR. The first and second Ca ions bound to sites III and IV (stage I), while the third and fourth bound to sites I and II (stage II). Zn2+, Hg2+ and Mn2+ bound to the first and third Ca2+-binding sites, but not to the second and fourth. Zn2+, Hg2+ or Mn2+ could bind to the first Ca2+-binding site by themselves and could bind to the third site only after the conformational change which occurs when two Ca2+ ions bind to first and second sites. Although Mg2+ did not bind to the first, second or fourth Ca2+-binding sites, it did bind to the third site. These results suggest that the order of Ca2+-binding and the order of affinity of the binding sites are not parallel; the first and third Ca2+-binding sites have high Ca2+-affinity, with the third being highest, whereas the second and fourth sites are of lower affinity. Also, we suggest in this study that the first and second sites are exposed on the surface of the protein, while the third and fourth ones are buried in the interior; the latter are exposed by the conformational change accompanying the binding of calcium to the first and second sites. Furthermore, the form of the interface by which calmodulin binds to target enzyme was altered slowly and continuously by the calcium-induced conformational change. The target enzyme was chosen and bound selectively to calmodulin among various enzymes by each interface form.

Animals↗

PubMed1989

Biological effects of lipopolysaccharide from Achromobacter stenohalis on lymphocytes and macrophages.

The immunopotentiating activities of lipopolysaccharide from Achromobacter stenohalis (A-LPS) were examined. A-LPS was structurally atypical and gave no endotoxin shock in A-LPS-inoculated mice. Analysis in vitro showed that A-LPS was a potent activator of both macrophages and B-lymphocytes. After macrophage stimulation with A-LPS, interleukin-1 (IL-1) secretion, interferon (IFN) production and chemiluminescence (CL) response were induced. A-LPS was a potent mitogen for spleen lymphocytes. However, induction of interleukin-2 (IL-2) secretion in T lymphocytes was not observed. These activities of A-LPS were similar to or higher than that of enterobacterial LPS.

Alcaligenes↗

PubMed1989

Comparative effects of mammalian pancreastatins on the pancreatic exocrine secretion.

We have reported that porcine pancreastatin inhibits cholecystokinin (CCK)-stimulated pancreatic exocrine secretion in conscious rats. In the present study, the effects of mammalian pancreastatins on exocrine pancreatic functions in rats were compared using synthetic pancreastatins (porcine, bovine, human, and rat). Rats were prepared with cannulae draining pure pancreatic juice and bile separately and a duodenal cannula to return bile-pancreatic juice to the intestine and with a jugular vein cannula. After 90-min basal collection of pancreatic juice, CCK-8 (100 pmol/(kg.h] was infused for 3 h with or without pancreastatins (100 pmol/(kg.h]. All pancreastatins significantly inhibited protein output at an equivalent molar potency. These results suggest that mammalian pancreastatins have the same biological activity of a comparable magnitude and exert a similar biological action on the exocrine pancreas.

Amino Acid Sequence↗

PubMed1989

[Surgical treatment of rheumatic tricuspid valve disease].

The rheumatic tricuspid valve is relatively rare in this country. We report the study on surgical treatment of 27 patients with rheumatic tricuspid valve. Surgical procedure on 7 cases out of them was tricuspid valve replacement (TVR) with bioprosthesis and tricuspid valvuloplasty (TVP) was performed in the remaining 20 cases. There were two operative deaths in TVR group, however, there were no major complications, such as thrombosed valve, the valve dysfunction or prosthetic valve endocarditis in the remaining five cases after the operation. The method of TVP in twenty cases consisted of two Kay's TAPs, six tricuspid commissurotomies (OTC), ten OTC with Key's TAPs and two OTC with DeVega's TAPs. Doppler cardiography (DCG) revealed residual tricuspid regurgitation (TR) more than 3/4 degrees in 7 cases of TVP group immediately after operation. Moreover, the increment of residual TR was seen in 7 cases during the following period and TVR was performed in 3 cases out of these 7 cases. In conclusion, it is suggested that TVR may be preferred to TVP for the rheumatic tricuspid valve because of severe residual TR in many cases of TVP group.

Bioprosthesis↗

PubMed1989

[Report of a case of iatrogenic pseudoaneurysm of right subclavian artery].

A case of iatrogenic right subclavian artery pseudoaneurysm which had disappeared spontaneously without surgical procedure, was presented. Among several diagnostic imaging modalities, ultrasonic color doppler method was considered most useful to visualize the anatomy and hemodynamics of the artery and the aneurysm.

Aged↗

PubMed1989

[Results of tricuspid valve replacement using xenograft bioprostheses].

Thirty-two cases of tricuspid valve replacement were done with bioprostheses during the period from 1979 to 1986 at our institution. In these cases there were 19 cases of acquired valvular diseases, 10 cases of congenital types of heart diseases and other 2 cases were another genesis. Seven different kinds of bioprostheses were utilized: 30 were bovine pericardial xenografts and 2 were porcine xenografts. In postoperative hemodynamic study, right ventricular end-diastolic pressure and right atrial pressure significantly decreased after tricuspid valve replacement. RV ejection fraction were reduced but there was no statistic significance when compared to the preoperative data. There were 5 patients who showed postoperative atrio-ventricular block and two of them needed permanent pacemaker implantation. Six patients died in postoperative period and other 3 died in late follow-up period. However, these was no mortality directly related to prosthetic valvular failure. In follow-up study, there was no episode of valve thrombosis nor pulmonary embolism. Prosthetic endocarditis was not encountered during this observation period. One patient showed mild degree of tricuspid regurgitation who had severe pulmonary hypertension even after the operation. Based on our experience, we concluded that the bovine pericardial xenograft may be the best choice for the TVR because of its anti-thrombogenicity. However, mechanical valve will be better choice for the patients who are complicated with severe pulmonary hypertension.

Adult↗

PubMed1988

Interaction of human parathyroid hormone-related peptide with parathyroid hormone receptors in clonal rat osteosarcoma cells.

Synthetic peptides corresponding to the amino-terminal region of the human parathyroid hormone-related peptide (hPTHrp) were used to characterize the interaction of hPTHrp with parathyroid hormone (PTH) receptors in clonal rat osteosarcoma cells (ROS 17/2.8). Both hPTHrp-(1-34) and [Tyr40]hPTHrp-(1-40) showed full agonist activity in stimulating cyclic AMP accumulation in ROS cells; human PTHrp-(1-34) was approximately 2.5-fold as potent as hPTH-(1-34). Both [Tyr-40]hPTHrp-(3-40) and hPTH-(3-34) inhibited the cyclic AMP increase induced by either hPTHrp or PTH with parallel dose-inhibition curves. Binding to intact ROS cells of a 125I-labeled [Tyr40]hPTHrp-(1-40) (125I-[Tyr40]hPTHrp-(1-40)) which retains full biological activity was time- and temperature-dependent and reversible. Binding of 125I-[Tyr40]hPTHrp-(1-40) and 125I-labeled [Nle8, Nle18, Tyr34]bovine PTH-(1-34)NH2 to ROS cells was competed for, to the same extent and with the comparable potency, by either unlabeled hPTHrp or PTH peptides. The binding capacity and affinity of receptors in ROS cells were strikingly similar for hPTHrp and PTH. Affinity cross-linking with either radioligand resulted in high affinity, specific labeling of an apparently identical macromolecule centering at Mr = 80,000, which was detected in sodium dodecyl sulfate-polyacrylamide gel electrophoresis in both reducing and nonreducing conditions. The data indicate that hPTHrp and PTH, their amino-terminal fragments at least, interact with the identical receptors with regard to affinity, capacity, specificity, and physicochemical characteristics in osteoblastic ROS 17/2.8 cells.

Animals↗

PubMed1988

Bioactivity of synthetic human pancreastatin on exocrine pancreas.

A biological activities of synthetic human pancreastatin (1-52) and its C-terminal fragment (24-52) were evaluated for the first time in the conscious rats. Both pancreastatins inhibited CCK-stimulated pancreatic secretion in a range of 20-200 pmol/kg/h with the same potency, indicating that the C-terminal portion of this peptide has a full biological activity. The relative molar potency of this substance compared to that of porcine pancreastatin was equivalent. This study suggests that human pancreastatin has the same biological activity as that of porcine, and plays a biological action in the exocrine pancreas.

Animals↗

PubMed1988

Human parathyroid hormone related protein fragment-(1-34) had glucose-6-phosphate dehydrogenase activity on distal convoluted tubules in cytochemical bioassay.

In the present study, the action of parathyroid hormone related protein (PTHrP) on glucose-6-phosphate dehydrogenase (G6PD) activity of the distal convoluted tubules was examined utilizing cytochemical bioassay (CBA). Recently full amino acid residues of human PTHrP (hPTHrP), one of the causative agents of HHM, was identified based on the cDNA clone using BEN cells. We synthesized hPTHrP-(1-34) and examined the effect of this protein on G6PD activities on the distal convoluted tubules, and compared its bioactivity to that of human parathyroid hormone (hPTH)-(1-84). hPTHrP-(1-34) stimulated G6PD activity in a log linear fashion with equivalent activity to that of hPTH-(1-84) on a molar basis. Conclusively, we found that PTHrP act on distal convoluted tubules similar to hPTH.

Animals↗

PubMed1988

Role of sulphated tyrosine residue in influencing the biologic activity of human cholecystokinin-33.

To evaluate the role of the sulphated tyrosine residue in position 27 in human cholecystokinin-33, parallel bioassay of the sulphated form of human cholecystokinin-33 and the unsulphated form of human cholecystokinin-33 was performed on the pancreatic protein secretion. Both peptides increased the protein output in a dose-related manner. However, the sulphated form possessed a considerably higher activity than the sulphated form. The relative potency of the unsulphated human cholecystokinin-33 compared to that of the sulphated human cholecystokinin-33 (taken as 1.0) was 0.08. From the results, it was suggested that the sulphated tyrosine may play an important role in controlling the activity of the longer molecular forms as well as that of the smaller forms of cholecystokinin.

Animals↗

PubMed1988

Effect of synthetic human cholecystokinin-33 on exocrine pancreas.

Synthetic human cholecystokinin-33 was first evaluated with respect to the biological activity on the pancreatic protein secretion. Human cholecystokinin-33 increased pancreatic protein secretion in a dose-related manner. The relative molar potency of this substance compared to that of synthetic cholecystokinin-8 (taken as 1.0) was 0.92. This study supports the concept that longer molecular forms of cholecystokinin are quantitatively important mediators of biological action of cholecystokinin on the pancreas.

Animals↗