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Biomedical subjects

A Hara

Publications and source records attributed to A Hara.

At least 559 records · Page 31Linked to original sources
PubMed1984

Abnormalities of glycosphingolipids in mucopolysaccharidosis type III B.

Glycosphingolipids from brain, liver, and spleen of a patient with mucopolysaccharidosis type III B were quantitatively analyzed. Neutral glycosphingolipids containing glucosylceramide, lactosylceramide, globotriaosylceramide, globotetraosylceramide, and gangliotriaosylceramide were increased in the brain, while the contents of galactosylceramide and galactosylceramide I3-sulfate were decreased. The total ganglioside levels were low in the grey matter (522 micrograms N-acetylneuraminic acid/g) and high in the white matter (342 micrograms N-acetylneuraminic acid/g), when compared with the normal values (744-918 micrograms/g in grey matter and 80-180 micrograms/g in white matter). The ganglioside compositions were characterized by a high proportion of II3-N-acetylneuraminosylgangliotriaosylceramide (GM2), II3-N-acetylneuraminosyllactosylceramide (GM3), and II3-(N-acetylneuraminosyl)2lactosylceramide (GD3). An unusual band of protein in place of an ordinary band of Wolfgram protein was detected as a major band by sodium dodecylsulfate-polyacrylamide gel electrophoresis. The low levels of 4-eicosasphingenine in the brain gangliosides indicated that the disturbance of the sphingolipid metabolism already began at age 3 at the latest and that the brain remained immature. These abnormal glycosphingolipids and protein as well as the accumulation of heparan sulfate explain in part the severe progressive mental retardation which is most characteristic of the mucopolysaccharidosis III B. Abnormalities of glycosphingolipids in the liver and spleen are also found.

Acetylglucosaminidase↗
PubMed1983

Isolation and characterization of multiforms of aldehyde reductase in chicken kidney.

Three multiforms of NADPH-dependent aldehyde reductase have been purified to homogeneity from chicken kidney. The enzymes were monomeric proteins with similar molecular weights around 39 000 but with different pI values. Two of them exhibited, almost the same heat stability, a broad optimal pH of 6-6.5 and preference for NADPH as a cofactor. They were high-Km aldehyde reductases which reduced various aldehydes, hexonates, alpha-diketones, xylose, glucuronolactone and ethyl acetoacetate, and which were inhibited to similar degrees by heavy metal ions, organic acids, p-chloromercuribenzoate, indomethacin and phenobarbital. The third aldehyde reductase was distinct from the other two enzymes in its heat lability, sharp acidic pH optimum of 6.0, and dual cofactor specificity. The enzyme showed low Km values for the above-mentioned substrates except hexonates and 4-carboxybenzaldehyde, and it specifically reduced lauryl aldehyde, acetoin and ketosteroids. This enzyme was less sensitive to the above-mentioned inhibitors than the high-Km aldehyde reductases, but the enzyme was moderately inhibited by chlorpromazine and was activated about 1.5 times by the addition of sulfate ions. It was demonstrated using antibodies against one of the high-Km forms and the low-Km form of aldehyde reductase that the two high-Km forms were immunologically identical with each other but not with the low-Km form, and that the high-Km and low-Km forms were widely distributed in various tissues of chicken.

Alcohol Oxidoreductases↗
PubMed1983

Guanosine 5'-triphosphate, 3'-diphosphate 5'-phosphohydrolase. Purification and substrate specificity.

The regulatory nucleotide guanosine 5'-diphosphate, 3'-diphosphate (ppGpp) and its precursor guanosine 5'-triphosphate, 3'-diphosphate (pppGpp) are accumulated during stringent response in bacterial cells. The enzyme pppGpp-5'-phosphohydrolase, which catalyzes the conversion of pppGpp to ppGpp, was partially purified from Escherichia coli. It has Mr = 140,000 and an apparent Km of 0.11 mM for pppGpp. It requires Mg2+ and a monovalent cation. NH4+ is preferred over K+, while Na+ is inactive. The enzyme does not hydrolyze GTP, ATP, pppApp, or ppGpp. It is also not effectively inhibited by these nucleotides. pppGpp-5'-phosphohydrolase hydrolyzes the 3'-monophosphate analog pppGp equally well (apparent Km of 0.13 mM), yielding the recently identified MS III nucleotide (ppGp). pppGpp-5'-phosphohydrolase does not have RNA 5'-terminal gamma-phosphatase activity; however, 5'-terminal phosphates are released by pppGpp-5'-phosphohydrolase when the GTP-terminated RNA chains are first converted into oligonucleotides by RNase A treatment. pppGpp-5'-phosphohydrolase was found to actively hydrolyze the dinucleotide fragment pppGpNp but exhibited very low activity toward longer chain fragments. The 3'-unphosphorylated dinucleotide pppGpN was, however, not hydrolyzed. The ability of pppGpp-5'-phosphohydrolase to hydrolyze pppGpp, pppGp, and pppGpNp, but not pppG and pppGpN, indicates that pppGpp-5'-phosphohydrolase is rather nonspecific toward the 3'-OH substitutions of the substrates although a free, unsubstituted phosphate group at the 3'-OH position is essential.

Cations, Monovalent↗
PubMed1983

Affinity separation of an acid phosphatase from rat tissues and Gaucher spleen with immobilized Cibacron Blue.

An acid phosphatase species which was activated by Fe2+ was determined to be partially soluble but mainly particulate in rat spleen. The particulate enzyme could be extracted into 1 M KCl. This enzyme bound to Cibacron Blue-immobilized Sepharose (Blue-Sepharose) and was desorbed by 2 M KCl with a good yield, while the other acid phosphatases in rat spleen did not adsorb on Blue-Sepharose. The enzymes eluted on Blue-Sepharose chromatography of both the soluble and particulate fractions were electrophoretically identical. The enzyme hydrolyzed aryl monophosphates, phosphoproteins, and nucleoside di- and triphosphates. The activity for the three kinds of substrate was similarly activated by Fe2+, ascorbic acid and cysteine, and inhibited by molybdate, Cu2+ and F-. Cibacron Blue inhibited the enzyme competitively with respect to a substrate, p-nitrophenyl phosphate, but kinetic analysis suggested that more than one dye molecule binds to the enzyme. The Blue-Sepharose technique could be applied not only to quantitative separation of acid phosphatases similar to the spleen enzyme from bone and epidermis of rat, but also to that of a tartrate-resistant acid phosphatase from human spleen with Gaucher's disease.

Acid Phosphatase↗
PubMed1983

Electrophysiologic testing of visual functions for vitrectomy candidates. I. Results in eyes with known fundus diseases.

A combination of various electrophysiologic tests--simultaneous recording of VER and ERG, EER, and single-flash ERG--is proposed to assess visual function in eyes being considered for vitrectomy. To establish the validity of the method, eyes of normal subjects and of some patients with clear media and types of ocular pathology often associated with opaque vitreous were tested. A higher stimulus threshold for VER than for ERG recorded simultaneously can be used to diagnose severe optic atrophy in eyes with opaque media. EER reflected the status of the retinal circulation and the function of the optic nerve, rather than the extent of the tractional retinal detachment in diabetic retinopathy. As electrical stimulation to the retina is little affected by opaque media, the EER can be a useful test in massive vitreous hemorrhage, diabetic retinopathy, and rhegmatogenous retinal detachment. Single-flash ERG was compared with ERG recorded with the response-summation technique. The b/a wave amplitude ratio in single-flash ERG was useful in assessing the middle layer of the retina in opaque media, whereas the latter technique, though useful when recorded simultaneously with VER, distorts the shape of the responses in such a way as to simulate the findings in retinal ischemia.

Diabetic Retinopathy↗
PubMed1983

Effect of a conjugate of daunomycin and purified polyclonal or monoclonal antibodies to rat alpha-fetoprotein on the growth of alpha-fetoprotein-producing tumor cells.

Monoclonal antibodies to rat alpha-fetoprotein (AFP) were produced by hybridization of mouse myeloma cells with spleen cells from mice immunized with rat AFP. The monoclonal antibodies as well as horse anti-rat AFP antibodies were coupled via a dextran bridge to daunomycin. Both types of conjugates were tested for their antitumor activity in vitro and in vivo. They were equally cytotoxic to the rat AH66 hepatoma cell line in culture. Rats challenged with hepatoma cells were treated with the conjugates by either intraperitoneal or intravenous injection. Daunomycin conjugates with horse-anti-AFP and monoclonal mouse anti-AFP were capable of delaying the tumor development more efficiently than were the controls of antibodies or free drug, mixtures of drug with antibodies, and a conjugate of drug and normal Ig. The specific conjugates were considerably more effective when the treatments were given intravenously. The specific conjugates produced 60% long-term survival, whereas the controls only slightly delayed tumor development.

Animals↗
PubMed1983

Generation mechanism of the negative endocochlear potential during early stage of anoxia.

To investigate the generation mechanism of the -EP in anoxic cochlea, the perilymphatic space was perfused with solution of various K+ concentrations in 38 guinea pigs when the -EP was maximally reduced by anoxia. Although the perfusion of scala tympani and vestibuli with Ringer-Locke solution or that of scala vestibuli with 154 mM K+ solution did not have any effect upon the -EP, the potential was elevated to 0 mV when the scala tympani was perfused with 154 mM K+ solution. Furthermore, the elevation of the potential was less remarkable when the K+ concentration in perfusate was reduced. The level of the potential during perfusion was closely related to K+ concentration in perfusates. The present results strongly suggest that the -EP is the result of the K+ diffusion potential and this diffusion mechanism is performed through the organ of Corti.

Animals↗
PubMed1983

Studies on the molecular weight of active and inactive renins in essential hypertension.

The molecular weight (MW) of active renin (AR) and inactive renin (IR) was investigated in individual plasma samples from 15 essential hypertensive and 5 normal subjects. The patients with essential hypertension were classified into 3 subgroups: low plasma renin activity (PRA), normal PRA and high PRA. The MW of AR and IR was estimated by Sephadex G-100 gel filtration. IR in the eluates was activated with trypsin. Plasma renin activity and renin activity in eluates were measured by radioimmunoassay of angiotensin I. At least 3 sizes of AR (MW: 48,000, 53,000 and 57,000) and 2 sizes of IR (MW: 53,000 and 57,000) were discovered, and the MW of AR was less than or equal to the MW of IR. The larger AR was predominant in the low PRA group and the smaller one in the high PRA group. This was also true for IR. This relation was also observed in the 2 types (high renin and low renin) of pooled plasma. In high renin pooled plasma the MW of AR and IR was about 48,000 and 54,000, respectively, while both were about 56,000 in low renin pooled plasma. It appears that the larger type of AR and IR remains in the circulation in the suppressed renin state, and that the smaller type of renins enters into the circulation when the secretion of renins is enhanced.

Enzyme Precursors↗
PubMed1983

The effect of maternal antigenic stimulation upon the active immune responsiveness of their offspring.

Pregnant mice were stimulated by sheep erythrocytes (SRBC) and the active immune responses of their offspring were investigated. The offspring whose mothers were stimulated with SRBC did not develop either IgM or IgG plaque-forming cell (PFC) target cells. From the dose response of pregnant mice for inducing suppression, enough doses (10(8)-10(10) cells of SRBC) for inducing primary anti-SRBC PFC could establish suppression in the young. Both intravenous and intraperitoneal administration of SRBC induced almost complete suppression of the specific PFC response (98.6-95.2%), but only partial suppression (57.8%) was induced by subcutaneous injection. For suppression to take place, female mice had to be injected with SRBC from 2 days before fertilization to day 16 of gestation. Suppression of the PFC response was not obtained when SRBC were given 3 days before fertilization or just 24 hr before delivery. This suppressive effect on the PFC response persisted until the 15th week after birth. In these newborn mice, detectable amounts of specific anti-SRBC antibodies were found. After exchanging mothers and newborns, the stimulated newborns fostered by normal mothers were still unresponsive following antigenic stimulation, even though a specific antibody from the mother was not detected. However, normal newborns nursed by stimulated mothers could respond to SRBC injection, no matter how the specific antibodies were transferred. Possible mechanisms of immunosuppression of the PFC response by antibody transmitted by the mother to her offspring are discussed.

Age Factors↗
PubMed1983

[Surgical treatment of renovascular hypertension with special reference to the indications for reconstructive surgery].

Based on the retrospective analysis of 38 cases of renovascular hypertension treated by surgical intervention, the following indications are proposed for arterial reconstructive surgery: younger age of patient, short duration of hypertension, renin-mediated hypertension and extent and functional significance of the obstructing arterial lesion, favorable level of renal function in the affected side, and renal function threatened by advanced progressive vascular disease, surgically correctable lesion, and focal, unilateral renal arterial atherosclerosis without generalized atherosclerosis, good surgical risk, and hypertension not responding to medical treatment. Although the clinical use of the angiotensin I converting enzyme inhibitor and induction of percutaneous transluminal angioplasty can provide a new approach to non-surgical treatment for renovascular hypertension, the long-term use of antihypertensive drugs induces gradual decrease in renal function. Surgical treatment is best reserved for the patient on whom the available data meet the above criteria for vascular surgery.

Adult↗
PubMed1983

Detection of D-erythro and L-threo sphingosine bases in preparative sphingosylphosphorylcholine and its N-acylated derivatives and some evidence of their different chemical configurations.

Sphingosylphosphorylcholine prepared from native sphingomyelin by the Kaller procedure was found to comprise about 70% of the L-threo (2S, 3S) isomer and 30% of the D-erythro (2S, 3R) isomer. This analytical result was obtained by gas-liquid chromatography (GLC) of trimethylsilyl derivatives of N-acetylsphingosines which were prepared by enzymatic hydrolysis of synthetic N-acetylsphingosylphosphorylcholines with Clostridium perfringens phospholipase C. Some other evidence of the different chemical configuration between the erythro and threo isomers of synthetic N-acylated sphingosylphosphorylcholines was also provided by thin layer chromatography (TLC), optical rotatory dispersion (ORD), and fast atom bombardment (FAB) mass spectrometry.

Acylation↗
PubMed1983

Abnormal protein and lipid compositions of the cerebral myelin of a patient with maple syrup urine disease.

Biochemical analyses were performed on the myelin isolated from the brain tissue of a patient with maple syrup urine disease. He was mostly treated by dietary management from day 8 after his birth until he died at 4 years and 5 months of age. It was found that the myelin contained major proteolipid-protein and high molecular weight protein and a very minor basic protein. The lipid composition of the myelin showed a marked decrease in phosphatidylethanolamine, but there was no remarkable reduction of cerebroside and sulfatide as well as other phospholipids in the myelin. Although the ganglioside composition of the myelin indicated that GM1 was a major ganglioside just like in the normal myelin, the myelin had an abnormal composition of an higher proportion of GD3 and a lower proportion of GM4, GD1b and GT1b. However, overall fatty acid compositions of the myelin lipids seemed rather normal.

Child, Preschool↗
PubMed1983

[Evaluation of correlation between radioactivity and exposure rate of irradiated concrete and stainless steel].

Cylindrical concrete and stainless steel blocks were irradiated one week by the cyclotron of Institute for Nuclear Study of University of Tokyo. Their gamma-ray activities were measured by a high-purity Ge( HPGe ) detector and simultaneously the residual exposure rates were measured by the GM survey-meter. Radionuclides and their gamma-ray activities were obtained by dividing the peak counts of the measured pulse height spectra by the peak efficiencies. For this purpose, the HPGe detector having known sensitive region in good accuracy was used, and its peak efficiency to these cylindrical sources was calculated by the PEAK Monte Carlo code including the self-absorption correction. The residual exposure rates were obtained from the simple analytical calculation by using these gamma-ray activities uniformly distributed in the concrete and stainless steel blocks. The calculated exposure rates showed very good agreement with those measured by the GM survey-meter. From this comparison, the relationship between gamma-ray activities and residual exposure rates were evaluated in good accuracy for these volume samples.

Gamma Rays↗