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Biomedical subjects

S Imamura

Publications and source records attributed to S Imamura.

At least 415 records · Page 23Linked to original sources
PubMed1986

Antioxidant action of antimalarials.

The effects of antimalarials, chloroquine and quinacrine, on the generation of reactive oxygen species were examined both in polymorphonuclear leucocytes and in the xanthine-xanthine oxidase system. Antimalarials showed inhibitory effects on the production of reactive oxygen species probably by affecting cell functions, such as membrane phospholipid methylation. It is suggested that antimalarial agents can work as antioxidants at the site of inflammation protecting against auto-oxidative tissue damage with resultant anti-inflammatory effects.

Cells, Cultured↗
PubMed1986

Prurigo pigmentosa: a possible mechanism of action of sulfonamides.

The patient described here had all the clinical features (itchy red papules and reticular pigmentation) as well as the histological findings (lichenoid tissue reactions) of prurigo pigmentosa, a little-known disorder of unknown etiology, and responded well to sulfamethoxazole treatment. In order to investigate the mode of action of this drug and thus the underlying pathogenesis of this dermatosis, the effect of sulfamethoxazole on the production of oxygen intermediates (OIs) was examined both in the cell-mediated system and in the xanthine-xanthine oxidase system. It was found that therapeutic doses of the drug significantly reduced the hydroxyl radical levels, one of the most potent oxidants that might cause tissue injury. These findings suggest the possibility that OIs produced by infiltrated cells are involved in the inflammatory process of prurigo pigmentosa and that sulfonamides exert their anti-inflammatory effects by affecting OI generation which results in protection against lichenoid tissue reaction.

Administration, Oral↗
PubMed1986

Penis tuberculides: papulonecrotic tuberculides on the glans penis.

Two cases of penis tuberculides are described. Although this disease once used to be comparatively common in Japan, the number of people affected by the disease has recently decreased as the prevalence of tuberculosis has fallen. However, we can still find a few cases in the Japanese literature every year. Outside Japan, we can hardly find reports of this disease, except for a few cases reported under the title of 'Papulonecrotic tuberculides on the penis' from Northern European countries. In addition to reporting 2 cases, we summarize clinical features of this disease. Racial predisposition or endemic factors may be related to the tuberculides in such a special site.

Antitubercular Agents↗
PubMed1986

Erythema multiforme: a possible pathogenetic role of increased reactive oxygen species.

Recently, it has been suggested that reactive oxygen species (ROS) produced by activated polymorphonuclear leukocytes (PMNs) exert auto-oxidative tissue damage at the site of inflammation. In the present study, a possible role of ROS in the pathogenesis of erythema multiforme (EM) was investigated by determining the capacity of the sera from patients for generating ROS from PMNs. Significantly increased hydroxyl radical production was observed, which is one of the most potent ROS capable of causing tissue damage. This change was not observed when PMNs were incubated with sera from patients with bullous pemphigoid (BP) or inflammatory acne, indicating that this finding was not a common feature of immunologically mediated and/or inflammatory cutaneous disorders. Elevated C1q activities and depositions of immunoreactants in the blood vessels were also noticed in some patients. These findings suggest that ROS generated by PMNs are involved in the formation of cutaneous lesions of EM and that immune complexes (ICs) may provide an important mechanism in PMN activation.

Adult↗
PubMed1986

Decreased NK activity of nude mice receiving long-term ultraviolet irradiation: in relation to tumor induction.

We have serially evaluated the basal and poly I: C-enhanced NK activity of BALB/c X C57BL/6 F1 nude mice (CB6F1-nu/nu) receiving repeated ultraviolet (UV) exposures with the interval of 2-5 weeks until overt skin tumor(s) developed. Chronic UV exposure induced a dose dependent suppression of basal splenic NK activity. The latent period between the initial UV treatment and the appearance of the first overt skin tumor was 19 weeks. After that time, incidence of tumor development gradually increased until it became 69% at the last inspection (27th week). 89% of the tumors inspected were fibrosarcoma and the remaining revealed squamous cell carcinoma. The UV-induced suppression of NK activity was restored by poly I:C treatment before the tumor appearance; however, this restorative effect was significantly reduced thereafter.

Animals↗
PubMed1985

[Development of two assay systems of desialylated hCG specific for O-serine or N-asparagine linked carbohydrate chain and their clinical application].

Two specific and sensitive assays have been developed for the measurement of as-hCG in this study. These assay systems are immunoradiometric assays which utilize peanut lectin, Arachis hypogaea (PNA) or caster bean lectin, Ricin communis agglutinin (RCA-I), to selectively extract as-hCG and then directly quantify with purified and radiolabeled antiserum against hCG beta COOH terminal peptide (beta-CTP). PNA is highly specific for the terminal carbohydrate linkage Gal beta-(1----3)-GalNAc which is only exposed in hCG when the O-serine linked oligosaccharide of its unique beta-CTP region are desialylated. RCA-I is also specific for the terminal carbohydrate beta-D-Galp., especially the linkage of Gal beta-(1----4)-GlcNAc, which is exposed in hCG when the N-asparagine linked oligosaccharide of its alpha and beta subunits are desialylated. The assays (PNA-R525 and RCA-I-R525) are capable of reliably and accurately measuring as little as 0.01 and 0.002 pmoles as-hCG/ml without interference from hCG, respectively (crossreactivity: 0.1% and 0.03%). The urine concentrates of a patient with choriocarcinoma and a normal pregnant woman were fractionated by Sephadex G-100 gel filtration and total hCG and as-hCG levels were measured. When the fractions were analysed by beta-CTP RIA, there were two peaks of immunoreactive hCG in the urine of a patient with choriocarcinoma. The bigger molecular fractions were hCG of native size, and 16% of which was desialylated. The smaller molecular fraction was beta-CTP, and practically all of that was desialylated. Whereas, beta-CTP could not be observed, and only 1.5% of hCG of native size was desialylated in the urine of a normal pregnant woman. Although the absolute levels of as-hCG in the urine specimens increased as total hCG increased, the proportion of as-hCG decreased as total hCG concentration increased. The proportion of as-hCG in urine specimens from choriocarcinoma patients was higher than specimens from patients with hydatidiform mole (including invasive mole) in both these lectin immunoradiometric assay (LIRMA) systems. Also, the proportion of as-hCG in urine specimens from molar patients was higher than those from normal pregnant women using PNA as extracting reagent. Whereas, when RCA-I was used, there was no significant difference between specimens from molar patients and those from normal pregnant women.(ABSTRACT TRUNCATED AT 400 WORDS)

Asialoglycoproteins↗
PubMed1985

Characterization and comparison of two forms of human chorionic gonadotropin from hydatidiform moles with low and high immunoreactivity.

Two glycoproteins (LM-hCG and HM-hCG) with gonadotropic activity were purified from the chorionic tissue of patients with hydatidiform mole with low and high urinary human chorionic gonadotropin levels and were compared to each other. The immunologic, biologic, and physicochemical properties of the two preparations were very similar. Also, the quantities of LM-hCG and HM-hCG recovered from molar tissue from the two types of patients were similar. However, the molar tissue from patients who excreted high levels of human chorionic gonadotropin immunoreactivity also contained other molecular forms with apparent human chorionic gonadotropin immunoreactivity tissues from patients who excreted low levels did not. These latter molecular forms may account for the differences in the levels of human chorionic gonadotropin immunoreactivity excreted by the two types of patients.

Amino Acids↗
PubMed1985

Colloid body formation in bullous pemphigoid.

Thirty-eight biopsy specimens from 18 cases of bullous pemphigoid (BP) were observed using direct immunofluorescence (IF) techniques with fluorescein isothiocyanate (FITC)-labelled antisera against human serum factors. In addition to deposits of immunoglobulins and serum components at the basement-membrane zone (BMZ), 15 specimens from eight cases displayed homogeneous and globular fluorescent bodies in the uppermost dermis and/or the blisters when FITC-labelled antisera to human IgM and other serum factors were used. Using immunoperoxidase staining, haematoxylin/eosin (HE) and periodic acid-Schiff (PAS) staining, these immunoglobulin and/or complement-positive cell-sized bodies were shown to be slightly eosinophilic and PAS positive. Electron microscopy revealed entangled networks of microfilaments approximately 7-8 nm in diameter. These homogeneous, fibrillar bodies were histologically, immunohistologically and ultrastructurally indistinguishable from the colloid bodies found in lesional skins of lichen planus, lupus erythematosus, dermatomyositis and several other dermatoses. In BP, degenerated keratinocytes adjacent to the blister roof, may, after undergoing a filamentous change, drop off into the dermis and subsequently form homogeneous, fibrillar bodies in the uppermost dermis when reepithelization is completed.

Aged↗
PubMed1985

Histamine metabolism in skin of MRL/l mice.

Of several murine autoimmune models, MRL/Mp-lpr/lpr (MRL/l) mice are the most attractive from a dermatopathological point of view, because their skin lesions resemble the erythematous lesions of systemic lupus erythematosus (SLE). In order to clarify the pathogenesis of lupus dermatoses, histamine and its metabolizing activities in the skin of MRL/l mice were investigated. The specific activities of histamine-N-methyltransferase (HMT) in the skin of MRL/l mice were significantly lower than those in the skin of control mice i.e., MRL/Mp-+/+ (MRL/n), C57BL/6J, and BALB/c mice. In the dorsal lesional skin of MRL/l mice, HMT activities were markedly lower than those in normal abdominal skin. In addition, age-related analysis of HMT levels in the dorsal skin of MRL/l mice revealed that HMT activities reached their maximum at the age of 2 or 3 months and then decreased at 4 or 5 months when skin manifestation appeared: however, HMT activities in the abdominal skin increased almost linearly with age. There were no significant differences in histamine content in these mice, and diamine-oxidase activities were not detected in any skin specimens. From these results, it is suggested that impaired histamine metabolism is a particular biochemical feature of the skin of MRL/l mice.

Age Factors↗
PubMed1985

Impaired histamine metabolism in the Arthus reaction induced in guinea-pig skin.

The activities of two histamine-metabolizing enzymes, histamine-N-methyltransferase (HMT) and diamine oxidase (DAO), were examined in various types of experimentally induced cutaneous inflammations in guinea pigs. In intact guinea-pig skin, the specific activities of HMT and DAO were 24.8 +/- 1.7 pmol/min per milligram of protein or 0.930 +/- 0.097 pmol/min per milligram of the wet weight of skin specimen, and 6.0 +/- 0.7 pmol/min per milligram of protein or 0.189 +/- 0.011 pmol/min per milligram of the wet weight, respectively. Both enzyme activities were markedly reduced in skin lesions of the Arthus reaction (P less than 0.005), while those in dinitrochlorobenzene allergic dermatitis, croton-oil dermatitis, and the intact areas in Arthus-reaction-induced animals were almost within the normal limits. The activity of HMT decreased linearly with time from the onset of the Arthus reaction, reaching about 20% of the control activity at 48 h; the activity of DAO decreased even from the early stages of the reaction, and this decrease continued throughout first 48 h of the reaction. These results suggest that impaired histamine metabolism in the skin lesions of the reaction plays a distinct role in the formation and development of the Arthus reaction.

Amine Oxidase (Copper-Containing)↗
PubMed1985

The Langerhans cell granule is an adsorptive endocytic organelle.

The role of Langerhans cell granules (LCG) in adsorptive endocytosis was studied by using concanavalin A (Con A) and heterologous anti-epidermal cell serum (AES) as ligands. Isolated epidermal cells were obtained by trypsinization of guinea pig skin fragments and exposed to ferritin-conjugated Con A or AES followed by ferritin-conjugated second antibody at 37 degrees C for various times up to 30 min. Langerhans cells among the treated epidermal cells were observed by electron microscopy. Shortly after the incubation, a few LCG in the cell periphery were filled with ferritin particles in the bulb portion. After prolonged incubation, ferritin-containing LCG increased in number and seemed to move to the juxtanuclear area. The granules were derived from plasma membrane invaginations that collected ferritin particles in a saclike extension at the end. Some of these invaginations were apparently of coated pit origin. The contents in the bulb of LCG seemed to be delivered finally to intracellular degradation compartments. Our findings clearly demonstrate that LCG are an adsorptive endocytic organelle.

Adsorption↗