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Biomedical subjects

H Hirata

Publications and source records attributed to H Hirata.

At least 235 records · Page 13Linked to original sources
PubMed1988

Temporally dependent changes in response properties of dorsal horn neurons after dorsolateral funiculus lesions.

Previous studies in this laboratory have shown 1) that 19% of L6 and L7 dorsal horn cells in normal cats respond only with excitatory postsynaptic potentials (EPSPs) to sural nerve stimulation, and 2) that the distribution of dorsal horn neurons responding with impulses to sural nerve stimulation is increased in cats with chronic lateral funiculus lesions. The present study was undertaken to determine whether strengthening of subliminal sural nerve projections could account for the changes seen after lateral funiculus lesions and to explore the nature of these changes in greater detail. Ipsilateral L6 and L7 dorsal horn cells of cats with T12 dorsolateral funiculus (DLF) lesions were studied electrophysiologically at less than 1-30 days postoperatively (DPO) and were compared with similar cells recorded in normal cats. The major results were as follows. 1. Responsiveness to peripheral stimulation was depressed for up to 3 DPO following the lesions. 2. The percentage of L6 and L7 dorsal horn cells showing spontaneous activity was elevated at 3 DPO and declined to normal levels by 28 DPO. 3. The percentage of cells that responded to sural nerve stimulation increased over 3-30 DPO and was significantly greater than normal at 28-30 DPO. The increase in the percentage of cells giving impulses to sural nerve stimulation at 28-30 DPO was similar to the percentage of cells with subliminal responses to sural nerve stimulation in normal cats. A subpopulation of identified postsynaptic dorsal column neurons also showed a significant increase in the percentage that responded to sural nerve stimulation after DLF lesions. 4. The percentage of cells that had a cutaneous receptive field (RF) overlapping the region of skin innervated by the sural nerve also increased over time and was significantly greater than normal at 28-30 DPO. 5. Median low-threshold or high-threshold RF areas were not significantly greater than normal ipsilateral to DLF lesions at any survival time. 6. The proportions of low-threshold (LT), high-threshold (HT), and multireceptive (MR) cells were not significantly different from normal at any survival time from less than 1 to 30 DPO.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1988

Factor I (C3b inactivator) polymorphism among five populations in Eurasia.

Factor I (C3b inactivator) polymorphism in the Japanese (in Western and Southern Japan), Taiwanese, Nepalese and French was studied using isoelectric focusing on polyacrylamide gels. The exposure of passively blotted nitrocellulose membranes to glutaraldehyde vapor facilitated the subsequent immunodetection of a low concentration of factor I and permitted the reliable identification of the three phenotypes determined by two codominant alleles FI*A and FI*B. The data indicated a west-to-east genocline, ranging from France to Western Japan, in which FI*A changed from 0.006 to 0.120.

Alleles↗
PubMed1988

[Improved survival rates in Hodgkin's disease].

Results of treatment of 25 Hodgkin's disease patients at Kyushu University Hospital from 1981 to 1985 were reviewed. Total nodal irradiation or MOPP chemotherapy was used mainly. The actuarial 5-year survival rate, 87.2%, was significantly better than the 41.0% of 61 patients treated between 1966 and 1980 (P less than 0.01). However, 12 of the 24 patients in remission eventually relapsed. To further improve the survival rates of patients with Hodgkin's disease, technical improvements in total nodal irradiation and altering Adriamycin-containing chemotherapy protocol from MOPP chemotherapy are advisable.

Adult↗
PubMed1988

Synergistic therapeutic effect of combination therapy with OK-432 and interferon-alpha or -gamma on Meth-A ascites tumor in BALB/c mice.

A synergistic therapeutic effect on Meth-A ascites tumor was obtained in BALB/c mice by the simultaneous i.p. injection of OK-432 and interferon alpha A/D (IFN-alpha). BALB/c mice that were cured of their Meth-A tumors showed significant tumor-specific rechallenge resistance. Combined therapeutic effect was significantly weaker in nude mice than in haired mice. The stimulation of host T-cell immunity was indicated to be crucially important for obtaining cured mice. Natural killer activity of peritoneal exudate cells was enhanced and peaked on day 1 with IFN-alpha, on day 3 with OK-432, and was sustained for up to 5 days with combination therapy. Macrophage activity assayed by in vivo resistance to the challenge of Listeria monocytogenes was stronger in order of OK-432 greater than OK-432 + IFN-alpha greater than IFN-alpha. Cytotoxic T-lymphocyte activity induced by immunization with the allogeneic tumor was enhanced most strongly by OK-432 plus IFN-alpha treatment. Each of the agents had tumor inhibitory activity on the growth of Meth-A cells in vitro, and there was a slight additive effect when two agents were used together. These findings suggest that the synergistic therapeutic effect of OK-432 plus IFN-alpha treatment on Meth-A ascites tumor was partly due to the direct antitumor activity of these two agents, but was also due in part to the beneficial antitumor immune responses that were induced. A similar synergism on Meth-A tumor was also observed by OK-432 plus interferon gamma treatment. However, this combination therapy was not effective on MH-134 ascites tumor in C3H mice.

Animals↗
PubMed1987

Reconstitution of the proton translocating ATPase from bovine heart mitochondria into planar phospholipid bilayer membranes.

Proton translocating ATPase (F0F1) from bovine heart mitochondria was reconstituted into planar phospholipid bilayers, and its electrogenicity was directly demonstrated. The F0F1 ATPase was solubilized using 3-[(3-cholamidopropyl)-dimethylammonio]-1-propanesulfonic acid (CHAPS) as a detergent followed by sucrose density gradient centrifugation according to the method originally described by McEnery et al. for rat liver mitochondria (McEnery et al. (1986) J. Biol. Chem. 259, 4642-4651), with minor modifications. The purified ATPase was reconstituted into proteoliposomes and then reconstituted into planar phospholipid bilayers by the modified fusion method (Hirata et al. (1986) J. Biol. Chem. 261, 9839-9843). A short-circuit current of up to 0.4 pA was induced by adding ATP, and this current was suppressed by the F1 ATPase inhibitor NaN3 or by a specific mitochondrial F0 inhibitor, oligomycin. The direction of the current corresponded to the flow of positive charges from the F1 side to the F0 side. All these facts clearly demonstrate that the mitochondrial F0F1 ATPase was successfully reconstituted into planar phospholipid bilayers, and the current was generated by the ATPase.

Adenosine Triphosphate↗
PubMed1987

[Immunobiological studies of interferon-alpha A/D in comparison with a streptococcal preparation, OK-432].

In order to clarify the characteristics of interferon-alpha A/D (IFN-alpha) as a biological response modifier (BRM), several immunobiological activities were compared with OK-432. 1) Both IFN-alpha and OK-432 inhibited the multiplication of Meth-A cells in vitro. 2) IFN-alpha (2 X 10(5) IU, ip) augmented the NK activity of peritoneal exudate cells (PEC) and spleen cells, and the peak of NK activity was observed 1 day after injection. OK-432 (1 KE, ip) augmented the NK activity of PEC, but not of spleen cells, and the peak was 3 days after. 3) Macrophage activating activity was more potent with OK-432 (1 KE) than IFN-alpha (2 X 10(5) IU). 4) Induction of CTL against alloantigens was augmented by IFN-alpha and OK-432. 5) By the combination of IFN-alpha with OK-432, a synergistic antitumor effect was obtained against Meth-A ascites tumor. Immunobiological effects of IFN-alpha seemed to be somewhat different from those of OK-432. Therefore, the combination of the two agents might cause a synergistic antitumor effect.

Animals↗
PubMed1987

[Factors influencing the response of normal tissue to radiation].

The dose modifying effects of the age, anatomic location of the normal tissue, positioning of animal during irradiation, preliminary treatment, number of fractions and time interval between doses on response of the normal tissues to radiation were studied, using various kinds of response of mouse hind legs such as early skin reaction, epilation, skin contraction, ulcer formation, leg contraction and growth retardation of femur. The dose modifying factors varied with the kinds and the levels of injuries, meaning that it is very important to define what the critical normal tissue is and its end point first of all, when we discuss the dose modifying factors with respect to the therapeutic gain factors.

Alopecia↗
PubMed1987

[Brachytherapy--carcinoma of the tongue].

In a review of 193 patients with carcinoma of the tongue who underwent interstitial radiotherapy in our hospital from November 1978 to 1986, 5 year actuarial local control rate were 97%, 87%, 58% and 77% for T1, T2, T3 and T4 respectively. Mucosal ulcers with tissue defects and bone exposure of the mandible occurred in 5 years after the treatments, 6%, 22%, 44%, and 100% for T1, T2, T3 and T4, respectively. Therapeutic ratio was 1 in patients with T1 who underwent interstitial radiotherapy (70 Gy/7 days) alone while it was less than 1 in those with T2 or more. Therapeutic gain factor was less than 1 in patients with combined external radiotherapy.

Adult↗
PubMed1986

Direct measurement of the electrogenicity of the H+-ATPase from thermophilic bacterium PS3 reconstituted in planar phospholipid bilayers.

The proton-translocating ATPase of the thermophilic bacterium PS3 was incorporated into a planar phospholipid bilayer, and its electrogenicity was directly demonstrated. The enzyme (TF0F1) consists of a catalytic portion, F1, and a membrane-integrated portion, Fo. A short-circuit current of up to 1 nA/cm2 was generated upon the addition of ATP, and the direction of the current indicated the flow of positive charges from the TF1 side to the TF0 side. The generation of the electric current was progressively suppressed by the presence of an inhibitor of TF1 such as NaN3 or adenyl-5'-yl imidodiphosphate. An open-circuit membrane potential of 40-120 mV was also demonstrated (more negative on the TF1 side), which was inhibited by NaN3. Furthermore, an applied voltage of -180 mV (TF1 side negative) was sufficient to prevent the generation of electric current dependent on ATP hydrolysis, which indicated that the electrogenicity of TF0F1 is some 180 mV under the conditions studied. From these results it was tentatively concluded that the number of protons transported across the bilayer/mol of ATP is more than 3.

Adenosine Diphosphate↗
PubMed1986

Killer toxin from Hansenula mrakii selectively inhibits cell wall synthesis in a sensitive yeast.

Hansenula mrakii secretes extracellularly a killer toxin which kills sensitive Saccharomyces cerevisiae. In protoplasts of this yeast, the killer toxin selectively inhibited the synthesis of alkali-insoluble acid-insoluble polysaccharides consisting mainly of beta-glucan, but did not inhibit either the synthesis of other cell wall polysaccharides, such as mannan, chitin and alkali-insoluble acid-soluble polysaccharides, or the synthesis of protein. Consistent with these results, the toxin was inhibitory to the beta-(1,3)-glucan synthetase activity of a cell-free extract from sensitive S. cerevisiae.

Cell Wall↗
PubMed1986

Preparation of anti-bovine and porcine mu chain sera.

Absorption of anti-L chain antibodies contained in anti-IgM sera immunized with purified bovine and porcine IgM was undertaken by affinity chromatography on a column of Sepharose 4B, coupled with the normal follicular fluids of the respective species as an immunosorbent. Anti-L chain antibodies in both anti-IgM sera were completely absorbed without incurring reduction of the antibody titer, and anti-bovine and anti-porcine mu chain sera were prepared.

Animals↗
PubMed1986

Anion transport in astrocytes.

We have examined the question of anion-transport systems in glia using primary astrocyte cultures prepared from neonatal rat brains. These studies show that these cells have exchange or cotransport systems for Cl- that appear to be electrically neutral, that is, SITS-sensitive Cl-/Cl- or Cl-/HCO3- anion exchange, and furosemide- and bumetanide-sensitive Na+ + K+ + 2Cl- cotransport. These inhibitors inhibit a major component of the total 36Cl- flux and the remaining Cl- flux may be conductive; however, this conductive flux makes a small contribution to Em relative to K+, since large changes in [Cl-]o do not usually affect Em, which is predominantly a K+ diffusion potential. We have also found an alpha-receptor-mediated depolarization that is affected by imposed changes in Ecl. The alpha-receptor-mediated depolarization seen at normal [Cl-]o could be partially due to increased Cl- conductance because [Cl-]i appears to be several-fold higher than it would be if it were in equilibrium with the membrane potential.

Animals↗
PubMed1986

Structure of a beta-galactosidase gene of Bacillus stearothermophilus.

The nucleotide sequence of the bgaB gene, which encodes the thermostable beta-galactosidase I of Bacillus stearothermophilus, and its flanking region was determined. A 2,016-base-pair open reading frame observed was concluded to be for beta-galactosidase I (Mr 78,051) from observations that the amino acid composition of the enzyme and the sequence of 14 amino acids from the amino-terminus of the enzyme coincided with those deduced from this open frame. A 107-base-pair HaeIII-AluI fragment just upstream of the estimated Shine-Dalgarno sequence of the bgaB gene had promoter activity toward cat-86 (chloramphenicol acetyltransferase gene) and produced the enzyme at a level equivalent to 7% of the total cellular protein of B. subtilis. From the base sequence of this DNA region and the transcriptional start site determined by S1 nuclease mapping, the -35 and -10 sequences are estimated to be TTGACA and TAATTT, respectively, which are similar to the consensus sequence of B. subtilis sigma 43 RNA polymerase.

Amino Acid Sequence↗
PubMed1986

Structurally abnormal insulin in a diabetic patient. Characterization of the mutant insulin A3 (Val----Leu) isolated from the pancreas.

We have recently identified a diabetic patient with marked fasting hyperinsulinemia. Family study revealed that the abnormality was an autosomal dominant trait. High-performance liquid chromatography (HPLC) profile of the patient's serum insulin showed that she had an abnormal insulin in addition to a normal insulin. We have purified her insulin(s) from the specimen of her pancreas, which was biopsied during an operation of cholelithiasis. Insulin was also immunologically purified from the serum of her portal vein. The reverse-phase HPLC analysis revealed that the ratios of normal to abnormal insulin in the pancreas, portal vein, and peripheral vein were 5:4, 4:5, and 1:7, respectively. Radioreceptor assay for insulin using guinea pig kidney membrane revealed that the binding activities of the normal component insulin, the abnormal component insulin and her pancreatic insulin containing both components were 100, 5, and 50% of standard human insulin, respectively. The biological activities of the normal component, the abnormal component and her pancreatic insulin to stimulate glucose oxidation in rat adipocytes were found to be 100, 8, and 60% of standard human insulin, respectively. Analysis of amino acid sequences of the abnormal insulin purified from her pancreas strongly suggested the substitution of leucine for valine at the third position of the A chain, A3 (Val----Leu).

Adolescent↗
PubMed1986

[Differences in the immunostimulatory activity and antitumor therapeutic effect of OK-432 and N-CWS].

Immunobiological activities of OK-432 and N-CWS were studied in BALB/c-Meth-A and C3H-MH 134 systems. Peritoneal exudate cells obtained from mice injected i.p. with OK-432 or N-CWS showed stronger in vitro cytotoxicity against Meth-A and YAC-1 cells than did those from non-treated mice. Spleen cells from OK-432 or N-CWS-treated mice exhibited lower Con A mitogenic response in comparison with those from non-treated mice. When Meth-A or MH-134 tumor cells were admixed with OK-432 or N-CWS, the intradermally inoculated tumor cells showed no or slower growth than did those admixed with saline only. There were no significant differences in all the above mentioned activities between OK-432 and N-CWS, and there was no difference in the direct tumor inhibitory activity of the two agents in vitro. However, the administration of N-CWS had no therapeutic effect against i.p.-inoculated tumor cells while OK-432 showed a strong therapeutic effect by the same treatment schedule. Further studies are required to clarify the mechanisms responsible for the difference in the therapeutic effect of the two agents.

Animals↗