Search PubMed⌕ Search

Biomedical subjects

T Horio

Publications and source records attributed to T Horio.

At least 253 records · Page 14Linked to original sources
PubMed1984

Production and inhibition of solar urticaria by visible light exposure.

The mechanisms of production and inhibition of solar urticaria were investigated in two patients whose eruptions were induced by wavelengths ranging from approximately 400 to 500 nm. They developed urticarial reactions to their own sera, which had been exposed previously to light in vitro. The exposure of skin to light from which activating wavelengths were eliminated with a glass filter (O-55), immediately after the exposure to urticaria-eliciting light, significantly inhibited the development of urticaria. The irradiation with the filtered light prior to the exposure of urticaria-eliciting light revealed no inhibitory effect. The simultaneous exposure of action and inhibition spectra seemed to suppress urticaria formation. The exposure of the inhibition spectrum did not affect wheal formation produced by histamine and a histamine-releasing agent. The photosensitizer produced by the action spectrum may be inactivated by the inhibition spectrum, or the interaction between photosensitizer and antibody may be blocked by the irradiation with the inhibition spectrum.

Adult↗
PubMed1984

Reconstruction of photosynthetic, cyclic electron transport system from photoreaction unit, ubiquinone-10 protein, cytochrome c2 and polar lipids purified from Rhodospirillum rubrum.

It was previously reported that in chromatophores of Rhodospirillum rubrum, reaction center, which consists of three kinds of protein (Mm, about 78K), is a small fragment of a large protein complex (PRU; photoreaction unit), which contains six other kinds of protein including light-harvesting bacteriochlorophyll protein, has Mm of about 700K and is free of phospholipid [J. Biochem. 86, 1211-1224 (1979); 94, 1815-1826 (1983(]. In the present study, the photosynthetic, cyclic electron transport system sensitive to antimycin A was effectively reconstructed by incubating 60 nM PRU (which contained 1 mol of reaction center and 2 mol of ubiquinone-10 per mol) with 300 nM each of oxidized ubiquinone-10 protein, reduced cytochrome c2 and lipoamino acid (which were all purified from Rhodospirillum rubrum) in the presence of low concentrations of cholate and deoxycholate (pH 8.0). In the light, the cytochrome was oxidized while the quinone was reduced. The oxidation and reduction each progressed rapidly at first, then slowly, reaching maxima (steady states) 1-2 min after the light had been turned on. At the steady states, 30% of the cytochrome was oxidized while 11% of the total quinone was reduced. When the light was turned off, the original oxidation-reduction states of the cytochrome and quinone were restored at rapid rates initially then at slow rates. Antimycin A stimulated the slow rates in the light-on state and depressed them in the light-off state, but did not influence the fast rates. Ubiquinone-10 protein was required for the antibiotic-sensitive, slow oxidation reactions. This indicates that the slow rates were due to cyclic electron transport. Cytochrome c2 was tightly bound to PRU at a molar ratio of 1:1. This cytochrome as well as the quinone bound to PRU was responsible for the fast rates. PRU had other sites able to bind cytochrome c2 and ubiquinone-10 protein with Km of 0.4 and 0.1 microM, respectively. Of the polar lipids tested, lipoamino acid was the most effective for reconstruction, and its effect was maximal at 300 nM, which is far below its critical micelle concentration.

Bacterial Proteins↗
PubMed1984

Alterations in lectin binding to the epidermis following treatment with 8-methoxypsoralen plus long-wave ultraviolet radiation.

The alterations in lectin fluorescence stainings to the epidermis were examined in guinea pig skin treated with topical application of a 1% 8-methoxypsoralen (8-MOP) solution plus long-wave ultraviolet (UVA) radiation (1.5-3.5 J/cm2) (PUVA). Serial biopsy specimens taken up to 21 days postirradiation were stained with 8 commercially available lectins labeled with either fluorescein isothiocyanate (FITC) or biotin (followed by avidin D-FITC): Bandeiraea simplicifolia agglutinin I (BSA), concanavalin A (Con-A), Dolichos biflorus agglutinin (DBA), peanut agglutinin (PNA), Ricinus communis agglutinin I (RCA), soybean agglutinin (SBA), Ulex europeus agglutinin I (UEA), and wheat germ agglutinin (WGA). In normal guinea pig skin UEA staining was absent. Following PUVA treatment, UEA and DBA stainings became apparent or stronger in intensity after days 7-14 (UEA) and days 4-7 (DBA), respectively, and returned to negative or weak by days 14-21. Stainings with Con-A, SBA, and WGA gave remarkable decreases in intensity after days 2-4 and recovered to the baseline by days 7-14. Intensity of BSA, PNA, and RCA stainings was decreased to a lesser degree than the other lectins. Such changes were not produced by application of 8-MOP, UVA radiation (less than 10 J/cm2), UVB radiation (900-2700 mJ/cm2), or tape stripping. These results suggest that PUVA treatment perturbs the composition or organization of epidermal cell surface glycoconjugates to induce alterations in lectin stainings.

Animals↗
PubMed1984

Role of oxygen intermediates in UV-induced epidermal cell injury.

To investigate the role of oxygen intermediates (OIs) in sunburn cell (SC) formation and development of UV-inflammation in vivo, groups of mice were injected intravenously with OI scavengers, including bovine blood superoxide dismutase (SOD), bovine liver catalase, L-histidine, D-mannitol, and saline (controls) before and/or after UV irradiation with sunlamp tubes (mainly 280-320 nm; 300 mJ/cm2; UVR). Ear thickness was measured before and 6 and 24 h after UVR. Ears were removed 24 h after UVR and the number of SCs per unit length of ear epidermis was counted using hematoxylineosin stained sections. The number of SCs was significantly decreased (p less than 0.02) by a single injection of SOD (10-30 units/g body weight) given either just before or immediately after (less than 15 min) UVR, while SC formation was no longer suppressed by injections given more than 2 h before or after UVR. Four repeated injections of SOD (10 units/g) also reduced SC counts but did not significantly alter ear-swelling responses (ESR). Neither SC counts nor ESR were remarkably suppressed by 4 injections of any of the other active OI scavengers, inactivated SOD, or bovine serum albumin. A single injection of diethyldithiocarbamate, an SOD inactivator, significantly augmented SC formation (p less than 0.05), but did not change ESR. These findings suggest that OIs generated by UVR participate in SC formation but are not apparently involved in UV-edema.

Animals↗
PubMed1983

Potassium iodide in erythema nodosum and other erythematous dermatoses.

Potassium iodide therapy has a history of more than 150 years. It has been tried in many diseases in the past. However, with the development of modern medications indications for potassium iodide therapy are very limited. It is well known that potassium iodide is the drug of choice for sporotrichosis. Subacute nodular migratory panniculitis and erythema nodosum have also been treated successfully with this drug.

Erythema Multiforme↗
PubMed1983

Action of chlorophyllase purified from rye seedlings on light-harvesting bacteriochlorophyll of chromatophores and spheroplasts from Rhodospirillum rubrum.

1. The chlorophyllase [EC 3.1.1.14] purified from greened rye seedlings hydrolyzed the bacteriochlorophyll isolated from Rhodospirillum rubrum, but not the pigment bound to the membrane of chromatophores or spheroplasts from the bacterium. 2. Acetone, if added at such concentrations that the bound bacteriochlorophyll would not be solubilized, enabled the enzyme to hydrolyze the bound pigment. The acetone concentrations required for half the maximum hydrolysis rates were 16% with chromatophores and 7% with spheroplasts. 3. The enzymic hydrolysis of the bound bacteriochlorophyll in the presence of acetone removed bacteriochlorophyllide from the membrane, leaving its esterifying alcohol, possibly all-trans-geranylgeraniol, in situ. 4. Washing of chromatophores with 30% acetone removed about 10% of the bound bacteriochlorophyll. The bound pigment remaining after washing was not hydrolyzed by the enzyme unless acetone was added. 5. It seems possible that light-harvesting bacteriochlorophyll was mostly, if not all, bound to the inner surface of chromatophores (the outer surface of spheroplasts), having its esterifying alcohol residue buried in the membrane and its porphyrin residue emerging from the membrane into the inside solution; thus, chlorophyllase could not make contact with the ester linkage between the esterifying alcohol and porphyrin moieties of the pigment unless the esterifying alcohol residue was partly exposed.

Bacterial Chromatophores↗
PubMed1983

Structure of the extracellular ferredoxin from Rhodospirillum rubrum: close similarity to clostridial ferredoxins.

The amino acid sequence of an [8Fe-8S] ferredoxin isolated from the culture medium of Rhodospirillum rubrum, a photosynthetic purple non-sulfur bacterium, was determined by a combination of various conventional procedures. The sequence was A-Y-K-I-E-E-T-C-I-S-C-G-A-C-A-A-E-C-P-V-N-A-I-E-Q-G-D-T-I-F-V-V-N-A-D-T-C-I-D-C - G-N-C-A-N-V-C-P-V-G-A-P-V-A-E (55 amino acid residues). It lacked methionine, leucine, histidine, arginine, and tryptophan. The molecular weight was calculated to be 5,568 excluding iron and sulfur atoms. The distribution of 8 cysteine residues was exactly the same as that of clostridial-type ferredoxin, suggesting retention of the duplication of the bacterial ancestral ferredoxin gene. The extracellular ferredoxin of R. rubrum was compared with other ferredoxins observed in closely related photosynthetic bacteria and the evolutionary significance of this ferredoxin is discussed.

Amino Acid Sequence↗
PubMed1983

Chemical nature of protein complex of photoreaction unit including reaction center in chromatophores of photosynthetic bacterium, Rhodospirillum rubrum, as detected by successive dissociation method.

Reaction center of chromatophores of Rhodospirillum rubrum consists of three kinds of protein, H-, M-, and L-subunit, and is bound with many other kinds of protein to form a larger protein complex (PRU; photoreaction unit), which contains all the bacteriochlorophyll. In the present study, purified PRU was dissociated in a stepwise manner in the presence of various mixtures of lithium dodecyl sulfate, sodium cholate and/or sodium deoxycholate, and separated into five, smaller protein complexes (PL1, PL2, PL3, PL4, and PL4') by high-speed molecular-sieve chromatography. The protein complexes were analyzed for molecular mass (Mm), protein composition, and molecular weights of the constituent proteins by the chromatography described above and by lithium or sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The results suggest that PRU consisted of 1 molecule each of 40K, 39K, 31K (H-subunit), 25K (M-subunit), and 22K (L-subunit), about 12 molecules each of 12K (light-harvesting bacteriochlorophyll-protein) and 11K, and about 6 molecules each of 10K and 9K (the protein nomenclature refers to the apparent molecular weights); the measured and calculated Mm values were 650K and 547K, respectively. The compositions of the other protein complexes were as follows. PL1 = PRU-10K-9K (measured & calculated Mm, 520K & 409K); PL2 = PL1-39K (340K & 267K); PL3 = PL2-40K (160K & 147K); PL4 = PL3-31K-25K (90K & 82K); PL4' = 31K + 25K + 22K (inactivated reaction center) (90K & 78K). The molar ratios of 12K and 11K to 25K were lower in the dissociated protein complexes than in PRU, and they differed from one complex to another. The locations of the constituent proteins in PRU are discussed.

Bacterial Chromatophores↗
PubMed1983

Immunologic unresponsiveness induced by topical application of hapten to PUVA-treated skin in guinea pigs.

Pretreatment by topical application of 8-methoxypsoralen and subsequent exposure to long-wave ultraviolet light (PUVA) on the induction site of contact sensitization to dinitrochlorobenzene (DNCB) significantly diminished the challenge reactions in guinea pigs. A single treatment with PUVA in a small area was enough to exhibit such an effect. Furthermore, the animals that had been first exposed to DNCB through PUVA-treated skin failed to become sensitized to the subsequent sensitization regimen of the same hapten even through previously untreated skin. The unresponsiveness in these animals was hapten-specific, since their capacity to become sensitized to an unrelated hapten, oxasolon, was not impaired. The intraperitoneal administration of cyclophosphamide at a dose of 200 mg/kg shortly before contact sensitization reversed the unresponsiveness in tolerant animals. These findings suggest that tolerance in these animals is a specific immunologic unresponsiveness mediated by suppressor cells.

Animals↗
PubMed1983

The alterations of keratinocyte surface and basement membrane markers by treatment with 8-methoxypsoralen plus long-wave ultraviolet light.

The alterations of keratinocyte surface and basement membrane markers by treatment with 8-methoxypsoralen (8-MOP) plus long-wave ultraviolet (UVA) light (PUVA) were examined in guinea pig skin using immunofluorescence (IF) microscopy. Following a single PUVA treatment (UVA doses: 1.8 - 7.2 J/cm2), reactivity with pemphigus and pemphigoid sera, rabbit anti-guinea pig epidermal cell serum, and fluorescein-conjugated concanavalin A was decreased in intensity in a dose-dependent fashion. Fluorescence became distinctly less pronounced by day 2 postirradiation and recovered between days 6-10. IF with rabbit antiglomerular basement membrane antibodies, which cross-reacted with the basement membrane of the skin, apparently was unaltered within this energy dose range. 8-MOP or UVA alone did not change the reactivity with any reagent. These results suggest that PUVA treatment affects keratinocyte membrane markers and pemphigoid antigens but not some of the basement membrane antigens.

Animals↗
PubMed1983

Topical 8-methoxypsoralen photochemotherapy of psoriasis: a clinical study.

Topical psoralen plus UV-A irradiation (topical PUVA) was re-evaluated with regard to the timing of UV-A exposure. Symmetrical lesions of fifteen patients with psoriasis were treated with topical PUVA. One side was exposed to UV-A 2 h after topical application of I% 8-methoxypsoralen (2-h interval therapy), while the other side was exposed to the same dose of UV-A within 5 min of the topical application (non-interval therapy). Both regimens were effective. The non-interval therapy was preferred in one case, the 2-hour interval was preferred in three cases, and there was no clear difference in the other eleven cases. There was less tendency to burning with the non-interval therapy, and our study suggests that this is a useful regimen in the out-patient treatment of psoriasis.

Administration, Topical↗
PubMed1983

Spectrophotometric method for selective assay of the five isoenzymes of human lactate dehydrogenase, based on their different stabilities at alkaline pH.

After preincubation of human lactate dehydrogenase (EC 1.1.1.27) isoenzymes 1 through 5 with lactate at pH 9.4, 9.8, 10.25, and 10.6 at 30 degrees C for 10 min, the reduction of NAD+ was measured at the same pH values and temperature during the interval 1-2 min after adding the coenzyme. Relative to the reference activities measured at pH 8.7 by the method of Buhl et al. (Clin Chem 23: 1289-1295, 1977), the respective activities of isoenzymes 1 through 5 thus measured were 111, 104, 96, 68, and 0% at pH 9.4; 123, 108, 88, 0, and 0% at pH 9.8; 140, 100, 0, 0, and 0% at pH 10.25; and 138, 0, 0, 0, and 0% at pH 10.6. These relations allow selective assay of the respective isoenzymes in samples containing mixtures of them. Optimal conditions for such selective assay at 37 degrees C are reported.

Electrophoresis↗