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Biomedical subjects

A Shirahata

Publications and source records attributed to A Shirahata.

At least 109 records · Page 6Linked to original sources
PubMed1992

Protein C and protein S deficiency in thalassemic patients.

To investigate the status of the protein C-protein S anticoagulant pathway in thalassemic patients, we measured protein C and protein S levels of plasma of 30 adults and 18 children with beta-thalassemia/HbE disease, beta-thalassemia major and HbE disease. Mean +/- 1 SD values of protein C, protein S and other coagulant proteins produced by the liver were as follows: protein C 50.4 +/- 17.2%; protein S 58.8 +/- 25.5%; antithrombin III 78.1 +/- 12.8%; PLG 86.4 +/- 18.4%; prothrombin 71.0 +/- 13.1%; factor VII 72.7 +/- 21.5%; and factor X 79.2 +/- 15.6%. Protein C and protein S levels of thalassemic patients were significantly lower than those of other coagulant proteins produced by the liver. Decrease in protein C level was stronger than that of proteins S. gamma-Carboxylated protein C levels of splenectomized patients were significantly lower than those of nonsplenectomized patients. Severe decrease of protein C and protein S may be responsible for occurrence of thrombosis in thalassemic patients.

Adolescent↗
PubMed1992

[Benefits and problems of home infusion therapy].

A survey was performed to clarify the benefits and problems of home infusion therapy because 8 years had passed since this type of treatment was officially approved in Japan. Questionnaires were sent to hemophiliacs and the physicians in charge of hemophiliacs in the Kyushu district. The main results obtained from analysis of responses concerning 197 patients were as follows. 1) Out of 197, 140 patients were on home therapy programs. 2) The number of bleeding episodes was increased in 6.8%, decreased in 51.1% and unchanged in 42.1% of patients after the start of home infusion therapy programs. 3) The severity of bleeding symptoms was reduced in 92.9% of patients after the start of these programs. 4) After the start of home infusion therapy programs, the amount of blood products administered increased in 24.4%, decreased in 20.6% and was unchanged in 55.0%. 5) Complications such as abdominal pain, headache, ulticaria, itching, shivering, fever and discomfort were reported from 19 hemophiliacs. Only one of them visited the hospital due to severe abdominal pain which appeared immediately after home infusion of blood product. 6) It was indicated that better education or re-education of home infusion therapy is necessary for hemophiliacs and/or their families who are on home infusion therapy programs, because half of them had not received proper education concerning home infusion.

Blood Substitutes↗
PubMed1991

Putrescine or spermidine binding site of aminopropyltransferases and competitive inhibitors.

A model of the active site of aminopropyltransferases was proposed based on the study of a number of monoamino and diamino compounds as potential inhibitors and substrates, respectively, of spermidine synthase purified from pig liver. The active site seems to have a relatively large hydrophobic cavity adjacent to a negatively charged site, to which a protonated amino group of putrescine binds, with another amino group of putrescine being situated in the hydrophobic cavity as a free form to be aminopropylated by decarboxylated S-adenosylmethionine. On the basis of the above-mentioned model, another modified one was proposed for spermine synthase, and several compounds mentioned model, another modified one was proposed for spermine synthase, and several compounds designed according to the modified model were found to potently inhibit spermine synthase, purified from rat brain, in competition with spermidine. The newly developed inhibitors were about two orders of magnitude more potent in vitro than a known inhibitor of spermine synthase, dimethyl(5'-adenosyl)sulfonium perchlorate.

Animals↗
PubMed1991

Polyamine-linked sepharoses: preparation and application to mammalian spermine synthase.

Seven different polyamine-linked Sepharose derivatives were prepared for the affinity chromatography of spermidine and spermine binding macromolecules: Spermine synthase from rat and hog brain was used as a model protein with a spermidine binding site. Comparative studies of the affinities of the enzymes for the seven matrixes suggested that two negative charges, three to four methylene groups apart, should be present at the decarboxylated S-adenosylmethionine binding site and should improve the binding of the enzyme to the Sepharose derivative. Two negative charges at the spermidine binding site would be expected to do the same. Three affinity matrixes linked with 1,17-diamino-4,9,14-triazaheptadecane, 1,21-diamino-4,9,13,18-tetraazaheneicosane, and 5-spermine carboxylic acid, respectively, had an affinity for spermine synthases higher than that of spermine-Sepharose, which has been used for the purification of spermine synthase. The first of these matrixes was used and proved to be effective for the purification.

Animals↗
PubMed1991

[Plasma levels of antithrombin III, thrombin-antithrombin III complex, alpha 2 plasmin inhibitor and plasmin alpha 2 plasmin inhibitor complex in normal and sick newborn infants].

Both bleeding and thrombosis are commonly seen in newborn infants because of their imbalance of coagulation and fibrinolysis system. In order to clarify some aspects of the hemostatic characteristics during neonatal period, we measured the levels of antithrombin-III (AT-III), thrombin AT-III complex (TAT), alpha 2-plasmin inhibitor (alpha 2PI) and plasmin alpha 2PI complex (PIC) in 137 normal and sick newborn infants. The results were as follows 1) AT-III levels in normal neonates were significantly low as compared with them in normal adults, and further lower levels were found in sick neonates. 2) TAT levels in sick neonates were significantly higher than those in either normal neonates and adults. In sick neonates, the incidence of abnormally high TAT values increased with DIC score points. 3) No significant difference of alpha 2PI level was seen between normal term neonates and adults. However, alpha 2PI levels in sick neonates were significantly low as compared with them in normal term neonates and adults. 4) PIC levels in either normal and sick infants were significantly higher than those in adults, but there was no significant difference in PIC levels between normal and sick newborn infants.

Antifibrinolytic Agents↗
PubMed1990

Spermine-like functions of N1, N12-bis(ethyl)spermine: stimulation of protein synthesis and cell growth and inhibition of gastric ulceration.

The spermine analogue N1, N12-bis(ethyl)spermine (BESPM) could mimic the functions of spermine in the following aspects: 1) BESPM could stimulate globin and ornithine decarboxylase synthesis in a rabbit reticulocyte cell-free system; 2) the addition of BESPM to the culture medium could recover cell growth of polyamine-deficient bovine lymphocytes; 3) spermidine uptake by bovine lymphocytes was inhibited by BESPM and spermine to a comparable degree; and 4) stress-induced gastric ulceration was inhibited by subcutaneous administration of BESPM. Since BESPM was less toxic than spermine for mice, BESPM or its derivatives may be useful for diseases which can be cured by polyamines.

Animals↗
PubMed1990

Blood coagulation findings and the efficacy of factor XIII concentrate in premature infants with intracranial hemorrhages.

Coagulation findings were examined in 55 cases of neonatal intracranial hemorrhages (ICH). Marked decreases of the platelet count, fibrinogen, factor XIII (F XIII) activity, were observed in these cases. However, the relatively mild increases in the alpha 2-plasmin inhibitor activity, alpha 2-plasmin inhibitor.plasmin complex and fibrin/fibrinogen degradation products level were observed and only about one third of the cases showed abnormal values. In consideration of these coagulation findings, fifty-eight cases of premature infants were randomly divided into a treated group with a F XIII concentrate and a non-treated group. Thirty cases were administered within 6 hours after delivery to investigate the preventive effects against intraventricular hemorrhages (IVH). Compared in frequencies between both groups limited to the cases with a high risk of IVH, the frequency in the treated group was two out of 13 (15.4%), significantly low (p less than 0.05), while it was six out of eight cases (75.0%) in the non-treated group. From these results it was concluded that a F XIII concentrate is effective in the prophylaxis of IVH in premature infants.

Blood Coagulation Tests↗
PubMed1989

[Successful treatment of an infant with fulminant hepatitis by factor VII concentrate].

A 2-month-old boy was admitted to our hospital because of poor sucking and jaundice. There were no abnormalities during the whole period of pregnancy and at birth. His mother was a HBeAb positive HBsAg carrier, but prophylactic maneuver such as anti-HB immunoglobulin and HB vaccine was not performed on him at birth. Physical examination on admission revealed mild disturbance of consciousness. The laboratory findings showed marked increments of serum bilirubin, GOT, GPT, and NH3, and prolongation of prothrombin time, activated partial thromboplastin time and hepaplastin test. Thus, he was diagnosed as fulminant hepatitis and treated with exchange transfusion once or twice a day. Biochemical data improved gradually, but hypocoagulable states remained unchanged. At that time we decided to use Factor VII concentrate, because we found that, among several coagulation factors, factor VII activity decreased most rapidly after exchange transfusion. The alternate therapy of exchange transfusion and Factor VII concentrate improved his coagulation abnormality without any side effects. Our experience suggests that the combination therapy of exchange transfusion and Factor VII concentrate may be useful for management of fulminant hepatitis, particularly for uncontrollable coagulopathy.

Acute Disease↗
PubMed1988

Regulation of mammalian S-adenosylmethionine decarboxylase.

S-Adenosylmethionine decarboxylase is a key enzyme in the biosynthesis of polyamines that is the rate limiting step in the formation of spermidine and spermine. The activity of S-adenosylmethionine decarboxylase is known to be regulated negatively by these polyamines and positively by their precursor, putrescine. A specific antiserum to S-adenosylmethionine decarboxylase was raised by immunizing rabbits with the homogeneous enzyme purified from rat prostate and a specific radioimmunoassay for the protein was set up. Using this radioimmunoassay it was found that a number of inhibitors of other steps in the polyamine biosynthetic pathway lead to increases in the amount of S-adenosylmethionine decarboxylase protein. These changes were caused by both a decreased rate of degradation and an increased rate of synthesis of the protein. The increased synthesis was due to two factors; a rise in the amount of translatable mRNA and an enhanced translation efficiency. The mRNA content of the prostate was substantially increased by treatment for 3 days with alpha-difluoromethylornithine (2% in drinking water). The translation of mRNA for S-adenosylmethionine decarboxylase was studied using a polyamine-depleted reticulocyte lysate supplemented with mRNA from rat prostate and the antiserum to precipitate the proteins corresponding to S-adenosylmethionine decarboxylase. These studies indicated that the enzyme was synthesized as an inactive precursor of Mr 37,000 which was converted to the enzyme sub-unit of Mr 32,000. The conversion of the precursor to the active sub-unit in vitro was increased by putrescine. The precursor could also be detected by immunoblotting of extracts from prostates of rats depleted of putrescine by treatment with the ornithine decarboxylase inhibitor, alpha-difluoromethylornithine. The translation of the S-adenosylmethionine decarboxylase mRNA in the reticulocyte lysates was strongly inhibited by the addition of spermidine or spermine demonstrating that polyamines directly inhibit the synthesis of S-adenosylmethionine decarboxylase. cDNA clones corresponding to S-adenosylmethionine decarboxylase were isolated using prostatic mRNA from polysomes enriched in S-adenosylmethionine decarboxylase by immunopurification. The use of these probes showed that rat ventral prostate contains two S-adenosylmethionine decarboxylase mRNA species of approximately 3.4 and 2.1 kb which differ in the 3' non-translated sequence. The sequence of these cDNAs will enable the amino acid sequence of the precursor to be obtained. This will provide evidence on the origin of the pyruvate prosthetic group of S-adenosylmethionine decarboxylase.(ABSTRACT TRUNCATED AT 400 WORDS)

Adenosylmethionine Decarboxylase↗
PubMed1988

Monospecific antiserum to rat spermidine synthase and its application to rat tissues and several mammals.

Monospecific antiserum to rat spermidine synthase was prepared by immunization of rabbits with purified enzyme protein from rat prostate, and its usefulness for analysis of spermidine synthase protein in not only rat tissues but also several other mammals was demonstrated by Western blotting and immunotitration of the enzyme activity. Application of the antiserum for elucidating the relationship between the enzyme activity and protein in normal rat tissues strongly suggested that marked difference in spermidine synthase activity among rat tissues depends solely on the difference in the amount of enzyme protein. Also, application of the antiserum for analyzing spermidine synthase from liver of mouse, rat, guinea pig, pig, and human, showed that the enzymes had a similar subunit molecular weight of 35,000 and a cross-reactivity with the antiserum, exhibiting almost the same immunoreactivity to mouse enzyme as to rat enzyme. Thus, it was suggested that the antiserum would be useful for further studies of mammalian spermidine synthase from the viewpoints of enzymology and molecular biology.

Animals↗
PubMed1987

DHF characterized by acute type DIC with increased vascular permeability.

Decreases in platelet count, fibrinogen concentration, factor VIII, antithrombin III and alpha 2-antiplasmin activities, increase in FDP-D fraction, and pleural effusion were observed transiently at early fever stage of DHF at grade II, indicating DHF patients had manifestations of the acute type of DIC with increased permeability of vascular wall.

Blood Coagulation Factors↗
PubMed1987

Protection against marked plasma leakage in dengue haemorrhagic fever by infusion of carbazochrome sodium sulfonate (AC-17).

Patients diagnosed clinically as having grade II dengue haemorrhagic fever, and confirmed serologically to have been recently infected by dengue virus were randomly assigned to two groups, to assess suppression of plasma leakage by intravenous administration of carbazochrome sodium sulfonate(AC-17). The double-blind prospective study over three successive epidemic periods included 39 patients in the placebo group, and 38 in the AC-17 group. The effects of the administration were evaluated with respect to pleural effusion of the chest X-ray films. A clear difference between the two groups was found in the numbers of patients with pleural effusion and severity of the pleural effusion thus the administration of AC-17 may be useful in eliminating the risk factors of severe bleeding and shock in dengue haemorrhagic fever.

Adrenochrome↗
PubMed1986

Increased content of mRNA for a precursor of S-adenosylmethionine decarboxylase in rat prostate after treatment with 2-difluoromethylornithine.

Total poly(A)-containing mRNA was isolated from rat ventral prostate and translated in a reticulocyte lysate system. The proteins corresponding to S-adenosylmethionine decarboxylase were precipitated with a specific antiserum to this protein. Two proteins were found; one having an Mr of 32,000, which corresponded to the subunit of this enzyme, and a larger protein of Mr 37,000. Immunopurification of polysomes with the antiserum to S-adenosylmethionine decarboxylase followed by mRNA extraction yielded an mRNA preparation which was 10-30% pure mRNA for S-adenosylmethionine decarboxylase. The translation of this mRNA showed clearly that the protein of Mr 37,000 was a precursor of the Mr 32,000 S-adenosylmethionine decarboxylase subunit. Treatment with 2-difluoromethylornithine, which depletes cellular spermidine and is known to increase the content of S-adenosylmethionine decarboxylase protein, led to a 9-fold increase in the content of its mRNA, but treatment with methylglyoxal bis(guanylhydrazone) did not change the mRNA content.

Adenosylmethionine Decarboxylase↗