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Biomedical subjects

H Tachikawa

Publications and source records attributed to H Tachikawa.

At least 55 records · Page 3Linked to original sources

A novel beta-galactoside-binding lectin in cultured murine lymphocytic leukemia cells.

Using affinity chromatography on lactosyl-Sepharose, a beta-galactoside-binding protein of 38 kDa was detected in mouse L1210 lymphocytic leukemia cells. Immunoblotting analysis revealed that it is distinct from any known larger molecular weight galectin. The partial amino acid sequences of the 38 kDa protein indicated that it is a novel member of the galectin family. This 38 kDa lectin is expressed in lymphocytic cell lines but not macrophage-like cell lines.

Amino Acid Sequence↗

Characterization of ficolins as novel elastin-binding proteins and molecular cloning of human ficolin-1.

A novel elastin-binding protein, EBP-37, was recently identified and purified from human plasma. Its partial amino acid sequences showed significant homology to porcine ficolins, which were originally purified from porcine uterus membranes as multimeric proteins with fibrinogen- and collagen-like domains. Here we report the presence of ficolins in an elastin-binding fraction of porcine plasma and the direct binding of recombinant porcine ficolin-alpha to elastin. In addition, a cDNA encoding a human counterpart of porcine ficolins that is composed of 319 amino acids and is different from EBP-37 was cloned and named human ficolin-1. Northern blotting of various human tissues revealed that human ficolin-1 mRNA is highly expressed in peripheral blood leukocytes. These data suggested that there are at least two kinds of ficolin-related proteins in both pig and human, and they may function as plasma proteins with elastin-binding activities.

Amino Acid Sequence↗

Synergistic renal protection by combining alkaline-diuresis with lipid peroxidation inhibitors in rhabdomyolysis: possible interaction between oxidant and non-oxidant mechanisms.

BACKGROUND AND PURPOSE: Heme-proteins, besides causing renal tubular obstruction, may contribute to rhabdomyolysis-induced renal injury through a heme-iron-mediated lipid peroxidation process. In the present study, we compared the combined therapy of a lipid peroxidation inhibitor, 21-aminosteroid (21-AS) and fluid-alkaline-mannitol (FAM) diuresis with either of them alone to determine the efficacy of the combination therapy and to delineate the roles of lipid peroxidation and cast formation. METHODS AND RESULTS: Employing Raman spectroscopy, we confirmed in vitro the ability of 21-AS to inhibit iron-induced fatty acid peroxidation. 21-AS was then administered to rats developing renal failure from glycerol-induced rhabdomyolysis. Although 21-AS inhibited rhabdomyolysis-induced plasma and renal lipid peroxidation, renal protection was incomplete. Administration of FAM to inhibit cast formation afforded a better renal protection. However, when these therapies were combined to inhibit both lipid peroxidation and cast formation, there was a synergistic renal functional protection. This was accompanied by a maximum inhibition of renal and plasma lipid peroxidation, as well as, renal tubular necrosis and cast formation. Compared to combination therapy, FAM therapy alone, despite identical volume, was accompanied by a higher tubular necrosis and cast formation. CONCLUSIONS: That combining a lipid peroxidation inhibitor with fluid-alkaline diuresis in rhabdomyolysis further lowers renal lipid peroxidation, tubular necrosis and cast formation and synergistically limits renal dysfunction (i) supports a role for lipid peroxidation in the pathophysiology of rhabdomyolysis ARF, (ii) underscores the role of the intratubular heme retention, a cause for tubular obstruction as well as a source for prodigious amount of iron, likely involved in the lipid peroxidation, and (iii) raises the possibility of interactions between non-oxidant and oxidant mechanisms.

Acute Kidney Injury↗

Isolation and characterization of a yeast gene, MPD1, the overexpression of which suppresses inviability caused by protein disulfide isomerase depletion.

MPD1, a yeast gene the overexpression of which suppresses the inviability caused by the loss of protein disulfide isomerase (PDI) was isolated and characterized. The MPD1 gene product retained a single disulfide isomerase active site sequence (APWCGHCK), an N-terminal putative signal sequence, and a C-terminal endoplasmic reticulum (ER) retention signal, and was a novel member of the PDI family. The gene product, identified in yeast extract, contained core size carbohydrates. MPD1 was not essential for growth, but overexpression of the gene suppressed the maturation defect of carboxypeptidase Y caused by PDI1 deletion, indicative of the related function to PDI in the yeast ER.

Amino Acid Sequence↗

EBP-37, a new elastin-binding protein in human plasma: structural similarity to ficolins, transforming growth factor-beta 1-binding proteins.

In order to study the elastin-binding factors in blood, human plasma was applied to an alpha-elastin-Sepharose column. The column-binding fraction contained a 37-kDa protein, which was tentatively named EBP-37. Partial amino acid sequences of EBP-37 were determined. It had collagenous and non-collagenous domains. Homology searches of the sequences revealed that the protein is very similar but not identical to ficolins, transforming growth factor-beta 1 (TGF-beta 1)-binding proteins from porcine uterus membranes. Direct interaction of EBP-37 with elastin was confirmed by demonstrating the binding of the isolated EBP-37 to alpha-elastin on a nitrocellulose membrane using the EBP-37-specific antiserum. The existence of oligomers and multimers crosslinked by disulfide bonds was demonstrated by immunoblot analysis. Possible functions of EBP-37 are discussed.

Amino Acid Sequence↗

Quality of peptic ulcer healing induced by lansoprazole and roxatidine.

This study reports preliminary results of a controlled, multicenter trial on the quality of ulcer healing induced by lansoprazole (LPZ) or roxatidine (R) in gastric ulcer (GU) or duodenal ulcer (DU) patients. Group A received LPZ 30 mg q.d. and group B received R 75 mg b.i.d. All drugs were given for 8 weeks in GU and for 6 weeks in DU. Endoscopy and gastric biopsy were performed to detect Helicobacter pylori before and on completion of treatment. The healing rates of groups A and B were 100 and 69.2%, respectively, in GU and 100 and 70.0%, respectively, in DU. This difference (p < 0.01) was significant between the two groups in GU. There was no significant difference between the two groups in the S2 stage shift rate in GU and DU. The H. pylori clearance rates of groups A and B were 33.3 and 20.0%, respectively, in GU and 62.5 and 33.3%, respectively, in DU. The differences in treatment response (healing rates and S2 shift rates) between the LPZ group and the R group may be related to the differences in suppression of acid secretion and in bactericidal effects on H. pylori.

2-Pyridinylmethylsulfinylbenzimidazoles↗

Excessive food aversion, compulsive exercise and decreased height gain due to fear of obesity in a prepubertal girl.

A case of a 7-year-old girl with a remarkable food aversion and excessive weight reduction caused by fear of obesity, which has been demonstrated in pubertal girls with symptoms partly similar to anorexia nervosa, is reported. Although the patient's weight was reduced to the upper limits of the normal range with diet and exercise, she reduced her food intake more strictly and did not at all eat food consisting of carbohydrates. Exercise was performed longer than before. Her weight continued to decrease and height velocity lowered from 6.0 to 4.1 cm/year (mean +/- SD of the age-matched normal girls: 5.5 +/- 0.74 cm/year). Her eating behavior was normalized without specific psychotherapy for anorexia nervosa. It is suggested that food aversion with weight loss and decrease in height gain due to fear of obesity may occur in prepubertal children as well as in adolescent girls.

Anorexia Nervosa↗

Calcium binding fraction detected from the brush border membrane during intestinal calcium absorption in the rat.

A fraction which had calcium binding activity was detected from the brush border membrane during intestinal calcium absorption in the rat. In situ duodenal loop experiment showed that 45Ca activity in mucosal homogenate, detergent-solubilized whole particulate fraction and detergent-solubilized brush border membrane was maximal at 30 min after the radioactive calcium solution was injected in the loop. The calcium radioactivities did not co-precipitate with anti-IMCal (integral membrane calcium binding protein) antibody. Gel permeation HPLC showed three calcium peaks from both solubilized whole particulate fraction and brush border membrane. In vitro calcium binding assay using the solubilized brush border membrane from the pylorus to proximal ileum showed the existence of specific binding sites with a dissociation constant of 2.19 +/- 0.27 mM (mean +/- SE) while the number of binding sites was 3.4 +/- 0.4 nmol/mg of protein. After in vitro binding, the solubilized brush border membrane was analyzed by gel filtration chromatography. Two calcium peaks, apparently 200 and 1 kDa, were separated and the former peak seemed to be the specific binding fraction but did not contain IMCal. This fraction may bind luminal calcium during intestinal calcium absorption.

Animals↗

Enzyme-based bilayer conducting polymer electrodes consisting of polymetallophthalocyanines and polypyrrole-glucose oxidase thin films.

Bilayer conducting polymer electrodes, which consist of a polymetallophthalocyanine (PMePc) and polypyrrole incorporating glucose oxidase (PPy-GOx), were prepared on the glassy-carbon electrode by the successive electrochemical deposition of two different polymers. The bilayer film electrodes showed catalytic behavior, which included an enhanced amperometric response current with the substrate and a significantly shifted oxidation potential (approximately 700 mV) of the response current. The bilayer electrodes also showed a fast response time and good stability with the substrate. A bilayer microelectrode, which was prepared by using both PCuPc and PPy-GOx polymer films, also showed a good amperometric response with the substrate.

Electrochemistry↗

[Purification and characterization of the membrane associated calmodulin from the human placenta].

The protein with the most predominant Ca2+ binding activity in membrane fractions of the human placenta was purified to electrophoretical homogeneity. This protein was identified as the membrane bound form of calmodulin based on the immunological cross reactivity and a number of biochemical properties. The membrane fraction of the human placenta contained 8.3% of the total cellular calmodulin activity. Approximately 2/3 of the membrane associated calmodulin was extracted by incubation with a Ca2+ chelating agent, EGTA, suggesting that this form of calmodulin is bound reversibly to membrane proteins in a Ca2+ dependent manner. However, the rest of the membrane associated calmodulin could not be extracted by EGTA treatment. The EGTA nonextractable calmodulin appears to be embedded in the membrane matrix.

Calcium-Binding Proteins↗

Glycosylation site binding protein and protein disulfide isomerase are identical and essential for cell viability in yeast.

Glycosylation site binding protein (GSBP) has been shown to be identical to protein disulfide isomerase (PDI; EC 5.3.4.1) in a variety of multicellular organisms. We have utilized immunological and biochemical techniques to determine if GSBP and PDI are identical in yeast. Antiserum prepared against yeast GSBP identified in microsomes by its ability to be labeled with a peptide photoaffinity probe was found to recognize PDI purified from yeast. Moreover, this purified yeast PDI was found to be specifically labeled by the photoaffinity probe originally used to identify GSBP in a variety of eukaryotes. On the basis of these observations, we conclude that yeast GSBP and PDI are the same protein. The structure of the yeast PDI gene revealed a product with sequence similarity to higher eukaryotic PDI/GSBP. Disruption of this gene in yeast resulted in a recessive lethal mutation, indicating that PDI/GSBP is required for cell viability.

Affinity Labels↗

Variceal bleeding after endoscopic injection sclerotherapy: an analysis of 108 subjects undergoing endoscopic injection sclerotherapy.

Among 108 cases of endoscopic injection sclerotherapy (EIS) performed from January 1984 through September 1989, post-EIS variceal bleeding occurred in 38 case (35%). Death was significantly more frequent among the post-EIS bleeders than non-bleeders (55% v. 27%). Background factors were analyzed for failure to prevent bleeding. The curve of the cumulative non-bleeding rate following emergency EIS (21 cases) was significantly lower (P less than 0.01) than that following elective EIS (22 cases), and there was more frequent rebleeding (13/21 v. 7/22) within a shorter mean period of time (4.9 months v. 14.1 months) in the former; association of hepatocellular carcinoma was also more frequent (13/21 v. 3/22). Continuation of drinking showed no difference between post-EIS bleeders (5/38) and non-bleeders (9/70). After complete variceal eradication the curve of the cumulative non-bleeding rate was significantly higher than after incomplete eradication (P less than 0.001). Following prophylactic EIS (65 cases) there was significantly less frequent bleeding (P less than 0.01) than following EIS performed after variceal rupture (43 cases). The risk of variceal bleeding after EIS can be minimized by complete eradication of varices at the initial EIS. Prophylactic EIS was suggested to contribute to reducing the frequency of post-EIS bleeding.

Emergencies↗

Development of an integrated filing system for endoscopic images.

A new integrated filing system for endoscopic images has been developed, comprising a main image filing system and subsystems located at different stations. A hybrid filing system made up of both digital and analog filing devices was introduced to construct this system that combines the merits of the two filing methods. Each subsystem provided with a video processor, is equipped with a digital filing device, and routine images were recorded in the analog image filing device of the main system. The use of a multi-input adapter enabled simultaneous input of analog images from up to 8 video processors. Recorded magneto-optical disks make it possible to recall the digital images at any station in the hospital; the disks are copied without image degradation and also utilised for image processing. This system promises reliable storage and integrated, efficient management of endoscopic information. It also costs less to install than the so-called PACS (picture archiving and communication system), which connects all the stations of the hospital using optical fiber cables.

Analog-Digital Conversion↗

Molecular structure of a yeast gene, PDI1, encoding protein disulfide isomerase that is essential for cell growth.

A genomic DNA clone for protein disulfide isomerase (PDI) of Saccharomyces cerevisiae was isolated by hybridization with synthesized oligonucleotide probes based on a partial amino acid sequence of yeast PDI. The introduction of a multiple copy plasmid carrying this fragment into yeast caused a tenfold increase in PDI specific activity and in the amount of PDI antigen in the extract. The gene on this fragment was named PDI1. The nucleotide sequence of the gene predicts a polypeptide of 522 amino acids with about 30% identity to mammalian PDIs. The predicted amino acid sequence contains an N-terminal signal peptide-like sequence, the C-terminal putative endoplasmic reticulum retention signal of yeast (HDEL), and two putative active site sequences of PDI (WCGHCK). The predicted polypeptide is acidic and contains five putative glycosylation sites, consistent with the molecular properties of the purified yeast PDI [T. Mizunaga et al. (1990) J. Biochem. 108, 846-851]. The PDI1 gene was mapped on chromosome III. A gene disruption experiment revealed that the PDI1 gene is essential for cell growth.

Amino Acid Sequence↗