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Biomedical subjects

Y Fujisawa

Publications and source records attributed to Y Fujisawa.

At least 19 recordsLinked to original sources
PubMed1992

Myristoylation-dependent membrane targeting and release of the HTLV-I Gag precursor, Pr53gag, in yeast.

The unprocessed HTLV-I Gag precursor, Pr53gag, was synthesized in yeast, Saccharomyces cerevisiae. The synthesized Pr53gag was myristoylated, associated with the cellular membrane, and released into the culture medium. The released Pr53gag was pelleted by centrifugation at 100,000 x g for 2 h. Conversion of Gly2 to Ala allowed synthesis of a non-myristoylated soluble Pr53gag which was not released into the culture medium. These results suggest that the release of the HTLV-I Gag precursors Pr53gag, occurs in yeast in a myristoylation-dependent manner.

Amino Acid Sequence↗
PubMed1992

Requirement of N- and C-terminal regions for enzymatic activity of human T-cell leukemia virus type I protease.

The requirement of N- and C-terminal regions for the enzymatic activity of human T-cell leukemia virus type I (HTLV-I) protease was investigated using a series of deletion mutants. The activity was analyzed by autoprocessing of the protease itself or by processing of the gag p53 precursor. The deletional analyses indicated that Asp38-Gly152 with an additional Met-Pro sequence at the N-terminus was probably sufficient for the enzymatic activity, although the mature HTLV-I protease consists of Pro33-Leu157. A molecular model of HTLV-I protease, which was constructed by comparison with the structure of Rous sarcoma virus protease, predicted that Pro33-Leu37 and Gly143-Leu147 would form a beta-sheet. Our experimental results and the model structure suggest that (a) five amino acids in the N-terminal region (Pro33-Leu37), which are thought to be involved in the beta-sheet, are not crucial for the enzymatic activity; (b) Pro153-Leu157 is not necessary but Pro148-Gly152 is important for the enzymatic activity, in addition to Gly143-Leu147 involved in the beta-sheet.

Amino Acid Sequence↗
PubMed1992

Hepatitis B virus envelope L protein particles. Synthesis and assembly in Saccharomyces cerevisiae, purification and characterization.

The hepatitis B virus envelope gene encodes three transmembrane proteins in frame; S, the product of S gene; M, the product of M (pre-S2 + S) gene; and L, the product of L (pre-S1 + pre-S2 + S) gene. Unlike the S and M proteins, attempts to efficiently synthesize L proteins and assemble them into L protein particles in various eukaryotic cells have been unsuccessful, probably because of the presence of the pre-S1 peptide with an unknown function which appears to be inhibitory to the host secretory apparatus. To investigate the role of the pre-S1 peptide, we constructed an L gene fused with a synthetic gene for chicken-lysozyme signal peptide (C-SIG) at the 5'-terminal and placed the resultant gene under the control of the yeast glyceraldehyde-3-phosphate dehydrogenase gene promoter. After the fused-C-SIG peptide was correctly processed by the yeast secretory apparatus, a yeast transformant synthesized a protein with a molecular mass of approximately 52 kDa at a level of 42% of the total soluble protein. Electron micrographic observation showed that the gene products assembled into 23-nm spherical and filamentous particles. The pre-S peptide of the gene product was deposited into the endoplasmic reticulum (ER) lumen and well-glycosylated. It seemed that the gene products were accumulated as particles in certain specific membrane structures of the yeast secretory apparatus. Moreover, both the amount of mRNAs specific for the L gene and the in vivo stability of the synthesized L proteins did not change significantly by the addition of the C-SIG gene. These findings indicated that, if the pre-S1 peptide penetrates the ER membrane efficiently, the L proteins can be synthesized cotranslationally, translocate across the ER membrane with its S region, and then assemble by themselves into the particle form. Therefore, the pre-S1 peptide may involve weak or reduced signal peptide activity for recognition by the secretory apparatus and/or for the transport of the pre-S peptide into the ER lumen.

Amino Acid Sequence↗
PubMed1992

Identification of polymerized-albumin receptor domain in the pre-S2 region of hepatitis B virus surface antigen M protein.

The pre-S2-coding region in the hepatitis B virus surface antigen M (P31; pre-S2 + S) protein gene was modified to identify a polymerized-albumin receptor (PAR) domain by deleting restriction fragments or performing site-directed mutagenesis. The modified M protein genes (M-P31x; x = d, e, f, h and i) were cloned into the yeast generalized-expression vector pGLD 906-1 and expressed in Saccharomyces cerevisiae under the control of yeast glyceraldehyde-3-phosphate dehydrogenase gene promoter. The PAR activities of these gene products suggested that the PAR domain is located in the hydrophilic and highly conserved domain in the pre-S2 region (around Leu12 approximately Tyr21). Antibodies specific for a pre-S2 peptide (Phe8 approximately Pro34, subtype adr), which covers the PAR domain, were purified from sera of rabbits immunized with yeast-derived M protein particles having a natural PAR domain. Immune electron microscopy showed that the purified antibodies could aggregate HBV particles. Therefore, it was speculated that the PAR domain overlapped with the dominant virus-neutralizing and virus-protecting epitopes.

Amino Acid Sequence↗
PubMed1992

The FMRFamide-related decapeptide of Mytilus contains a D-amino acid residue.

1. An FMRFamide-related decapeptide isolated from the anterior byssus retractor muscle (ABRM) of the bivalve mollusc, Mytilus edulis, was shown to have D-Leu as the second amino acid residue. 2. The excitatory effects of the peptide (Mytilus-FFRFamide) on the ABRM were not changed appreciably by substituting an L-Leu residue for the D-Leu residue.

Animals↗
PubMed1992

Regional hemodynamic effects of betaxolol, a new selective beta 1-blocker, and atenolol in conscious spontaneously hypertensive rats.

Betaxolol is a new beta-blocker that has been reported to have beta 1-selectivity, and it is devoid of both membrane stabilizing action and intrinsic sympathomimetic action. The effects of betaxolol on systemic and regional hemodynamics were examined in conscious spontaneously hypertensive rats (SHR) by a microsphere method and compared with the effects of atenolol. A single oral administration of betaxolol at 1 and 10 mg/kg decreased the mean arterial pressure in a dose-dependent manner. At the same doses, atenolol also showed a similar but weak hypotensive effect. Both of these drugs at the high dose decreased cardiac output and heart rate and at the low dose, did not. Total peripheral resistance decreased by only betaxolol at the low dose. Betaxolol showed a tendency to normalize the hemodynamic abnormalities which were observed in the kidney, spleen and gastrointestinal tract of SHR, while atenolol did not. It should be noted that betaxolol increased the flow rate in the kidney, which may be explained by its direct vasodilatory action on renal blood vessels. In conclusion, betaxolol showed an antihypertensive action at the doses of 1 and 10 mg/kg, exhibited the characteristics of a beta 1-blocker and produced preferable effects on regional hemodynamics in SHR.

Animals↗
PubMed1992

[Antiandrogen therapy of benign prostatic hypertrophy: clinical effects of allylestrenol evaluated by transrectal ultrasonographic measurement].

A multicenter trial was carried out on 100 patients with benign prostatic hypertrophy to elucidate the efficacy of anti-androgen therapy with allylestrenol (AE). AE was administered at a daily dose of 50 mg for 16 weeks to the patients and its efficacy was evaluated with subjective symptom scores, residual urine volume and uroflow rates. The effects of AE on prostatic volume and morphology were evaluated using transrectal ultrasound. Of these patients 65 completed the protocol, and only three patients withdrew from the study owing to side effects. Very modest adverse effects on sexual performance were seen in one patient. In this study, significant beneficial effects of AE on symptom scores, residual urine, maximum flow rate, and prostate size were demonstrated. However, volumetric reduction was not associated with urodynamic improvement. Prostatic shape was not changed throughout the study. These findings suggest that allylestrenol can be used as an alternative to prostatectomy in patients who are at high risk for surgery.

Aged↗
PubMed1992

[Pharmacokinetics and clinical studies of panipenem/betamipron in the pediatric field].

Panipenem/betamipron (PAPM/BP) is a mixture of panipenem (PAPM), carbapenem antibiotic, and betamipron (BP), N-benzoyl-beta-alanine. The adverse reaction to PAPM of the kidney is reduced by the addition of BP to PAPM which inhibits the anion transport in the kidney tubules. We studied the pharmacokinetics and the clinical efficacies of PAPM/BP in children and we evaluated the antibacterial activities of PAPM by determining MIC values of PAPM in vitro against organisms isolated in our children's hospital from January to December, 1990. 1. Pharmacokinetics 10 mg/kg of PAPM/BP (10 mg PAPM/10 mg BP) was administered intravenously by drip infusion to 7 children. The mean blood concentration of PAPM was 14.8 micrograms/ml at the peak, and the mean half life was 0.9 hours in blood. PAPM was not detected in blood 3 hours after the time when the peak values were attained. 2. Clinical studies 10 mg/kg of PAPM/BP was administered intravenously 3 times a day to 18 cases including 15 of respiratory infections, 2 of otitis media and 1 of sepsis. The clinical efficacies of PAPM/BP were excellent or good in 17 out of the 18 cases. All causative organisms isolated in 5 cases, Methicillin-sensitive Staphylococcus aureus (MSSA) (1 case), Streptococcus pneumoniae (1), Haemophilus influenzae (2) and Branhamella catarrhalis (1) were eradicated in a few days upon the administrations of PAPM/BP. No adverse reactions due to PAPM/BP were observed, but a slight elevation of platelet counts in blood was observed in 1 case, which was normalized soon after the end of the treatment. 3. Antibacterial activities in vitro(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
PubMed1991

Expression of human T-cell leukemia virus type I protease in Escherichia coli.

Human T-cell leukemia virus type I (HTLV-I) genome is believed to encode its own protease, although the protease has not yet been detected. To identify the HTLV-I protease, an in-frame gag (3' portion)-prt region was expressed in Escherichia coli. The 14-kDa product was detected using antisera against a synthetic peptide mimicking the fragment of HTLV-I protease, although the molecular weight of the primary translational product was 27,000. A cell extract had a proteolytic activity to cleave a synthetic peptide substrate containing the cleavage site of gag p19/p24 at the correct site in vitro. Replacement of the putative active site Asp-64 with Gly abolished both in vivo processing activity and in vitro proteolytic activity. These results suggest that the 14-kDa product is the mature enzymatically active HTLV-I protease generated through posttranslational autoprocessing in E. coli.

Amino Acid Sequence↗
PubMed1991

Increased insulin levels after OGTT load in peripheral blood and cerebrospinal fluid of patients with dementia of Alzheimer type.

An investigation was carried out to determine whether a disturbance of glycometabolism is associated with dementia of Alzheimer type (AD). The first part of the study was carried out on 108 AD patients and 57 normal controls (NCs). Neither the plasma level of insulin nor that of glucose differed significantly between the two groups before the oral glucose tolerance test (OGTT), whereas there was a significantly greater increase of the plasma insulin in the AD group than in the NC group after the OGTT. The second part of the study was carried out on 54 AD patients, 44 patients with vascular dementia (VD), and 26 NCs. Early in the morning after overnight fasting, there was no significant difference in the fasting plasma level of either glucose or insulin, or the cerebrospinal fluid (CSF) level of glucose, among the three groups, However, the CSF level of insulin was significantly higher in the AD group than in the other two groups. These results suggest that an abnormally high level of insulin, not only in the peripheral blood after OGTT load but also in the CSF after fasting, may be associated with the pathology of AD.

Aged↗
PubMed1991

A novel strategy for converting recombinant viral protein into high immunogenic antigen.

Interleukin 2 (IL-2) is a lymphokine promoting immune response and therefore has been investigated as an immunological adjuvant. In order to enhance the immunogenicity of recombinant viral protein, herpes simplex virus type 1 (HSV-1) glycoprotein D (gD), we genetically created a fusion protein consisting of gD and human IL-2. The fusion protein, without any other adjuvants, induced high antibody responses and cell-mediated immunity to HSV-1 in mice. Mice immunized with the fusion protein were protected against HSV-1 infection. The results indicate that IL-2-fusing can provide a means for converting a weak immunogenic protein into a high immunogenic antigen, and the strategy would be widely applicable to the other antigens for pathogens.

Adjuvants, Immunologic↗
PubMed1991

Induction of protection level of anti-pre-S2 antibodies in humans immunized with a novel hepatitis B vaccine consisting of M (pre-S2 + S) protein particles (a third generation vaccine).

An enzyme-linked immunosorbent assay (ELISA) for anti-pre-S2 antibodies was developed by the use of both recombinant yeast-derived S and M (pre-S2 + S) protein particles as antigens. By this ELISA was determined the amount of both human and chimpanzee anti-pre-S2 antibodies produced by a new type of yeast-derived hepatitis B (HB) vaccine (TGP-943, subtype adr), which consists of modified M protein particles. In seven randomly selected human individuals who were vaccinated intramuscularly with 10 micrograms (as a protein) TGP-943 three times (0, 4th and 24th week), a detectable level of anti-pre-S2 antibodies was found to be rapidly elicited at 4th or 8th week after the first vaccination. The protective level of anti-pre-S2 antibodies in humans was tentatively assessed by comparing the anti-pre-S2 antibody titres in the vaccinated human individuals with that in chimpanzees which produced only anti-pre-S2 antibodies to tolerate well against the challenge by 1000 chimpanzee infectious units of HBV (subtype ayw). From this assessment, it was speculated that all human individuals tested had already acquired the protective level of anti-pre-S2 antibodies at 4th or 8th week after the first vaccination with TGP-943.

Animals↗
PubMed1991

Effects of the neuropeptide APGW-amide and related compounds on molluscan muscles--GW-amide shows potent modulatory effects.

1. Effects of the molluscan neuropeptide APGW-amide and related compounds (the crustacean hormone RPCH, FAPGW-amide, PGW-amide, GW-amide and W-amide) were examined in several kinds of molluscan muscles. 2. All the compounds, except W-amide, showed qualitatively similar modulatory effects on contraction or relaxation of the muscles. The potency order of the compounds was found to be GW-amide greater than or equal to APGW-amide greater than FAPGW-amide greater than RPCH greater than PGW-amide. W-amide showed little or no effect even at 10(-4) M. 3. In the ABRM of Mytilus and the radula retractor muscle of Rapana, the active peptides were suggested to exhibit their modulatory effects by acting on the presynaptic sites in the muscles. 4. Nineteen GW-amide analogues, such as Gly-Trp-OH, Gly-Phe-NH2, D-Ala-Trp-NH2 and N-Gly-tryptamine, were also tested on some of the muscles, but all of them showed little or no effect.

Animals↗
PubMed1991

Arthroscopic meniscal repair with fibrin glue.

Since 1984 we have arthroscopically repaired 40 meniscal tears in 32 patients using fibrin glue in our operative technique. This technique was reported initially in 1985 (Ishimura M, Samma M, Habata T, Fujisawa Y. The use of fibrin glue for fresh knee injury. Cent Jpn Orthop Traumat 1985; 28:1404-8), with a more detailed study published in 1987 [Ishimura M, Samma M, Fujisawa Y, et al. Arthroscopic repair of the meniscus tears with fibrin glue. Arthroscopy (Jpn) 1987;12:31-6]. During the follow-up period, which ranged from 10 months to 6 years and 7 months (mean: 3 years and 8 months), only two patients complained of meniscal symptoms and underwent arthroscopic partial meniscectomy. Twenty patients with 25 repairs underwent repeat arthroscopy at an average of 5.7 months (range: 2 months-1 year and 2 months) after the initial repair. Twenty repairs were rated as good, four as fair, and one as poor by arthroscopic evaluation criteria. At present, the most appropriate use of this arthroscopic meniscal gluing technique is in tears in the posterior segment, which are difficult to suture without arthrotomy. Even a long tear with a stable reduced position can be expected to show good healing. When reduction of the tear is not stable, additional sutures should be used.

Adolescent↗
PubMed1991

Solubilization of steviolbioside and steviolmonoside with gamma-cyclodextrin and its application to selective syntheses of better sweet glycosides from stevioside and rubusoside.

1,4-alpha-Glucosylation at the 13-O-glycosyl moiety of stevioside (S) and rubusoside (RU) results in a significant increase of sweetness. Saponification of the 19-COO-beta-glucosyl linkage of S and RU yielded steviolbioside (SB) (= 13-O-beta-sophorosyl-steviol) and steviolmonoside (SM) (= 13-O-beta-glucosyl-steviol), respectively, both of which are poorly soluble in an acetate buffer. It was found that the solubilities of SM and SB in the buffer solution were remarkably increased in the presence of gamma-cyclodextrin (gamma-CD). SB was solubilized in the buffer solution with the aid of gamma-CD, and the solution was subjected to 1,4-alpha-transglucosylation by using a cyclodextrin glucanotransferase-starch system to give a mixture of products which were glucosylated at the 13-O-glycosyl moiety. This mixture was acetylated, and the acetate was subjected to chemical beta-glucosylation of 19-COOH followed by deacetylation to afford compounds which have superior sweetness to S. In the same way, derivatives with superior sweetness were selectively prepared from RU through SM.

Cyclodextrins↗
PubMed1991

Neurotransmitters and neuromodulators controlling the anterior byssus retractor muscle of Mytilus edulis.

1. The anterior byssus retractor muscle (ABRM) of Mytilus edulis is innervated by at least two kinds of nerves, excitatory and relaxing nerves. The principal neurotransmitters released from these nerves have been shown to be acetylcholine and serotonin, respectively. 2. Some other monoamines, such as dopamine and octopamine, and various peptides, such as FMRFamide-related peptides, Mytilus inhibitory peptides, SCP-related peptides and a catch-relaxing peptide, may also be involved in the regulation of the muscle as neurotransmitters or neuromodulators. 3. The ABRM seems to be typical of invertebrate muscles controlled by multiple neurotransmitters and neuromodulators.

Amino Acid Sequence↗
PubMed1991

A variety of Mytilus inhibitory peptides in the ABRM of Mytilus edulis: isolation and characterization.

1. Five species of Mytilus inhibitory peptides, MIP1-5, were isolated from acetone extracts of the anterior byssus retractor muscle (ABRM) of Mytilus edulis. MIP1 and MIP2 were shown to be S2-MIP and A2-MIP, respectively, first isolated from the pedal ganglia of the animal. 2. All the five peptides had a common C-terminal structure of -Pro-Xaa-Phe-Val-NH2, which was shown to be important for their biological activity. 3. The five MIPs showed similar inhibitory effects on contractions of the ABRM but did not affect catch tension and its relaxation. 4. In addition to the MIPs, catch-relaxing peptide (CARP) was also found in the ABRM.

Amino Acid Sequence↗