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Biomedical subjects

T Horio

Publications and source records attributed to T Horio.

At least 307 records · Page 17Linked to original sources
PubMed1979

Extracellular hydrogenase from photosynthetic bacterium, Rhodospirillum rubrum.

With Rhodospirillum rubrum, hydrogenase was found to exist partly as an extracellular enzyme in the culture medium. After 4-day cultivation, the total activity and the specific activity of the enzyme in the medium were about 10 times and 230 times as high as those in the crude extract obtained from disrupted cells. The time course for the production of hydrogenase during cultivation was studied.

Hydrogen↗
PubMed1979

Disintegration of Rhodospirillum rubrum chromatophore membrane into photoreaction units, reaction centers, and ubiquinone-10 protein with mixture of cholate and deoxycholate.

1. The membrane of Rhodospirillum rubrum chromatophores was disintegrated with mild detergents (cholate and deoxycholate) in order to study the spatial arrangement of the functional proteins in the photochemical apparatus and the electron transport system in the membrane. 2. The components solubilized from the membrane by a mixture of cholate and deoxycholate (C-DOC) were separated into four fractions by molecular-sieve chromatography in the presence of C-DOC; they were designated as F1, F2, F3, and F4 in the order of elution. The fractions were further purified by repeated molecular-sieve chromatography in the presence of C-DOC until each fraction was chromatographically homogeneous. 3. F1 appeared to be conjugated forms of F2. 4. The purified F2 was composed of a rigid complex having a weight of 7 X 10(5) daltons, containing approximately 10 different kinds of protein species with molecular weights of 3.8 X 10(4), 3.6 X 10(4), 3.5 X 10(4), 2.8 X 10(4), 2.7 X 10(4), 2.6 X 10(4), 1.3 X 10(4), 1.2 X 10(4), 1.1 X 10(4), and 1.0 X 10(4). The complex contained 33 bacteriochlorophylls, 4 iron atoms, and 90 phosphates, but no cytochrome, ubiquinone, or phospholipid. It showed the same reaction center activity as chromatophores, indicating that the complex was a unit of the photochemical apparatus (photoreaction unit). Each chromatophore of average size was estimated to possess about 24 photoreaction units. 5. The purified F3 showed an absorbance spectrum characteristic of reaction centers, and contained 3.4 bacteriochlorophylls, 2.0 bacteriopheophytins, and 1.9 acid-labile iron atoms, but no cytochrome or ubiquinone (C-DOC reaction center). It had a weight of 1.2 X 10(5) daltons, and the main components were 4 protein species with molecular weights of 2.8 X 10(4), 2.7 X 10(4), 2.6 X 10(4), and 1.0 X 10(4). 6. The purified F4 showed a molecular weight of about 11,000, and contained one mole of ubiquinone-10 per mole (ubiquinone-10 protein). 7. The reaction center activity of C-DOC reaction centers was stimulated by ubiquinone-10 protein. In addition, the reaction center oxidized reduced cytochrome c2 in the light, provided that ubiquinone-10 protein was present (photo-oxidase activity).

Bacterial Chromatophores↗
PubMed1979

Hydrophobic-ionic chromatography. Its application to purification of porcine pancreas enzymes.

1. All the porcine pancreas enzymes tested, regardless of their pI's were adsorbed on Amberlite CG-50 (a weakly acidic cation exchange resin) at pH 4, where the ion-exchange group (carboxyl group) is not dissociated. The adsorption is hardly influenced by ionic strength. 2. At pH 4, the adsorbed enzymes were partially eluted by organic solvents such as 50% propanol. 3. The adsorbed enzymes were effectively eluted by increasing the pH from 4 to 6. Trypsin (pI 10.5) was eluted before carboxypeptidase A (pI 4.5 AND 5.3) WITH 0.5 M acetate buffer, whereas the former enzyme was eluted after the latter enzyme with 0.2 M 3,3-dimethyl glutarate buffer. However, with either buffer, the elution order of enzymes was not always the same as the order of the pI's. 4. By a single Amberlite CG-50 column chromatography of porcine pancreas extracts, kallikrein, carboxypeptidase B, deoxyribonuclease, carboxypeptidase A, and trypsin were purified 100-fold, 16-fmately 13%. The purification procedures included treatment with protamine, ammonium sulfate fractionation, treatment with acid, DE-32 cellulose column chromatography, gel filtration on Sephadex G-100, preparative polyacrylamide gel electrophoresis, and affinity chromatography on 5' AMP-Sepharose 4B. The last procedure, affinity chromatography on 5' AMP-Sepharose 4B, was useful for the removal of other dehydrogenases. The enzyme which was homogeneous, as shown by polyacrylamide gel electrophoresis, had a molecular weight of about 92,000. The optimum pH was at 10.0 and isoelectric point at 5.2. The enzyme accepted both L-fucose and D-arabinose as substrate, but was specific for NAD+ as coenzyme. Km values were 0.15 mM, 1.4 mM, and 0.07 mM for L-fucose, D-arabinose, and NAD+, respectively. A single enzyme catalyzed the oxidation of L-fucose and D-arabinose, which had the same configurations of hydroxyl groups from C-2 to C-4. The reaction products obtained with L-fucose as substrate were L-fucono-lactone and L-fuconic acid. The L-fucono-lactone was an immediate product of oxidation and was hydrolyzed to L-fuconic acid spontaneously. This reaction was irreversible. Therefore, it is likely that L-fucose dehydrogenase is involved in the initial step of the catabolic pathway of L-fucose in rabbit liver.

Amylases↗
PubMed1979

Photosensitivity reaction to dibucaine. Case report and experimental induction.

In a 13-year-old girl, photoallergic dermatitis was caused by dibucaine hydrochloride, which was used as a local anesthetic in the treatment of her dental caries. The action spectrum for the photosensitivity reaction was in the long-wave ultraviolet (UVA) range. Spectrophotometrically, dibucaine absorbed UVA up to 380 nm, and in the vitro irradiated chemical showed an altered absorption spectrum. The agent is fluorescent under UVA light. The allergic photocontact sensitization could be experimentally induced in guinea pigs. The chemical properties and high sensitization rate of experimental induction suggested that dibucaine may be a potent photosensitizing chemical. Dibucaine should be included in routine photopatch test materials.

Adolescent↗
PubMed1979

Linear melorheostotic scleroderma with hypertrichosis.

On the basis of clinical features and histological findings, cutaneous manifestations of linear melorheostotic scleroderma are apparently derived from a localized proliferative disorder and are not secondary to bone changes. If the hypertrichosis has the same origin as the osteocutaneous changes, melorheostosis may represent a congenital disorder with both ectodermic and mesodermic components.

Adult↗
PubMed1978

Successive purification of several enzymes having affinities for phosphoric groups of substrates by affinity chromatography on P-cellulose.

Glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, glutathione reductase and pyruvate kinase of Candida utilis and baker's yeast, when in anionic form, were adsorbed on a cation exchanger, P-cellulose, due to affinities similar to those for the phosphoric groups of their respective substrates; thus, glucose-6-phosphate dehydrogenase was readily eluted by either NADP+ or NADPH, glutathione reductase by NADPH, 6-phosphogluconate dehydrogenase by 6-phosphogluconate, and pyruvate kinase by either ATP or ADP. This type of chromatography may be called "affinity-adsorption-elution chromatography"; the main principle is different from that of so-called affinity-elution chromatography. Based on these findings, a large-scale procedure suitable for successive purification of several enzymes having affinities for the phosphoric groups of their substrates was devised. As an example, glucose-6-phosphate dehydrogenase was highly purified from baker's yeast and crystallized.

Candida↗
PubMed1978

Complete stabilization of water-soluble hydrogenase from Rhodospirillum rubrum under air atmosphere with a high concentration of chloride ions.

Hydrogenase was easily solubilized from light-grown cells of R. rubrum with 10 mM Na ethylenediaminetetraacetate. The enzyme thus obtained was so stable that loss of its activity was undetectable during storage at room temperature for 6 months under air atmosphere, provided that NaCl, KCl or CsCl was present at greater than or equal to 0.7 M.

Aerobiosis↗
PubMed1978

Photocontact dermatitis from P-aminobenzoic acid.

A 6-year-old girl with xeroderma pigmentosum was contact and photocontact sensitized to PABA which had been used as a sunscreening agent. The activating wavelengths for photocontact dermatitis were in long-wave ultraviolet light. The experimental photocontact sensitization was not induced in guinea pigs. Although PABA is the most effective and harmless sunscreening agent for normal skin, it could induce photocontact sensitivity especially in diseased or damaged skin.

4-Aminobenzoic Acid↗
PubMed1978

Photosensitivity due to a fluorouracil derivative.

A photosensitive lichen planus-like eruption developed in a 63-year-old man during postoperative chemotherapy with 1-(2-tetrahydrofuryl)-5-fluorouracil. The action spectrum for the photosensitivity was in the long-wave ultraviolet light (UV-A). The reaction was reproducible on readministration of the drug and exposure to UV-A. At the time of this test, a flare-up phenomenon was observed at previously involved sites. The photopatch test was negative with the drug. Patients taking the drug who had no dermatitis were not sensitive to UV-A. These observations suggest that the photosensitivity that occurred in the patient was possibly photoallergic.

Fluorouracil↗
PubMed1978

Linear unilateral basal cell nevus with comedo-like lesions.

A 20-year-old woman had linear unilateral basal cell nevus with comedo-like lesions. Numerous papules were distributed on the left side of the upper aspect of the trunk in a zosteriform fashion. The indivisual lesions were hemispherical, pearly, and waxy tumors, some of which had central plugs. Histologic examination revealed polymorphous patterns that suggested that the tumor cells differentiated toward the apocrine glands, hair structures, and sebaceous glands. Ultrastructurally, the tumor strands were composed of fairly mature basal cells with well-developed tonofilaments and desmosomes.

Adult↗
PubMed1978

Photoallergic urticaria induced by visible light. Additional cases and further studies.

Four patients with solar urticaria induced by visible light developed an urticarial wheal at the site of injection of their own serum, which previously had been exposed to light in vitro. The in vitro-irradiated patients' sera did not produce the urticarial response in normal control subjects. Direct passive transfer studies with the patients' sera yeilded positive results, while reverse passive transfer studies showed negative results. Based on the experimental data, the patients' conditions might be induced by an allergic mechanism in which a circulating photoallergen appears to be an etiologic factor. One of the patients demonstrated an urticarial reaction at the site of injection of in vitro-irradiated normal serum as well as his own serum. The urticaria formation was blocked by intradermal injection of epinephrine but not by local injection of antihistamines. The repeated exposures to light had a beneficial effect on wheal formation in all cases.

Adult↗
PubMed1977

Resonance Raman study of the pH-dependent and detergent-induced structural alterations in the heme moiety of Rhodospirillum rubrum cytochrome c'.

The resonance Raman spectra and the structures of the heme moiety of Rhodospirillum rubrum cytochrome c' were investigated for its five states characterized by absorption spectra; Types-a and -n of the reduced form and Types-I, -II, and -III of the oxidized form. The frequency of the ligand-sensitive Raman line suggested the coordination of lysine (Nepsilon) at the sixth position of the heme iron of Type-n. The sixth ligand of Type-III was deduced to be either lysine or histidine but would not be methionine. Type-a and Type-II gave the Raman spectra of rather normal high spin type but Type-I was unusual in the sense that the frequencies of the Raman lines associated primarily with methine-bridge CC-stretching vibrations were relatively high in comparison with those of other high spin hemoproteins. Type-I was converted directly to Type-III upon the addition of SDS or 2-propanol but the conversion occurred via Type-II when pH was increased. Structural difference between the high spin hemes of Type-I and Type-II was discussed in detail.

Cytochrome c Group↗
PubMed1977

Solar uticaria. Photoallergen in a patient's serum.

A 45-year-old man had solar urticaria that was activated by visible light. Passive transfer of the reactivity with the patient's serum to the skin of normal recipients was accomplished. Results of reverse passive transfer studies were negative. The patient developed an urticarial wheal at the site of injection of his own serum that had been previously exposed to light in vitro. The experimental data suggested that his condition was attributable to an allergic response. Systemic administration of reserpine was of some therapeutic value, and increasing exposure to natural sunlight was associated with substantial in crease in his tolerance to sunlight. Unfortunately, the possible loss of reactivity that may occur in the natural course of the disease makes substantiation of the therapeutic effects difficult.

Allergens↗