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Biomedical subjects

S Kato

Publications and source records attributed to S Kato.

At least 1,189 records · Page 66Linked to original sources
PubMed1990

Synthesis and processing of a gp28/32 membrane glycoprotein induced by Marek's disease virus serotype 2.

The post-translational events leading from the precursor to the processed forms of a glycoprotein with an Mr of 28K to 32K (gp27/32) of Marek's disease virus (MDV) serotype 2 were examined with pulse-chase experiments and treatment with tunicamycin and monensin. Cell-free translation of infected cell mRNA followed by immunoprecipitation analysis suggested that a polypeptide with a size of 22K is the initial precursor. Experiments with endo-beta-N-acetylglucosaminidase H and endo-beta-N-acetylglucosaminidase F indicated that gp28/32 contains mostly N-linked oligosaccharides of the complex type. These studies showed that 22K, the initial product, is then processed through intermediates to the 28K to 32K form.

Electrophoresis, Polyacrylamide Gel↗
PubMed1990

Psoriatic arthritis of the hands in seven adults.

Psoriatic arthritis is defined as an association of psoriasis with an arthropathy characterized mainly by osteolytic changes in the X-ray. To assess its frequency among Japanese psoriatic patients and to characterize their signs and symptoms, we examined 51 patients (37 males, 14 females) for arthropathy of the fingers. Seven patients (5 males, 2 females) had abnormal X-ray findings of the hands. They were compared with psoriatic patients without arthritis epidemiologically, clinically, and hematologically. Metacarpal indices were also measured and compared with the results from rheumatic arthritis patients and controls.

Adult↗
PubMed1990

Eosinophilic polymyositis induced by tranilast.

A 38-year-old man with asthma developed eosinophilic polymyositis following the administration of Tranilast, an antiasthmatic agent. Low grade fever, erythematous rashes on the entire body, dysphagia, blood eosinophilia, elevations of serum creatine phosphokinase and myoglobin levels, and inverted T waves in the electrocardiogram were noted. A muscle biopsy showed focal degeneration of muscle fibers with an infiltrate of eosinophils and lymphocytes. A rechallenge with Tranilast resulted in erythema formation, blood eosinophilia, and elevations of some serum muscle enzymes and myoglobin levels. Tranilast was considered to be the causative agent. This is the first reported case of Tranilast-induced eosinophilic polymyositis.

Asthma↗
PubMed1990

Hemangiopericytoma: characteristic features observed by magnetic resonance imaging and angiography.

Hemangiopericytoma is a rare vascular tumor which may originate wherever there are capillaries. We report a case of this tumor occurring in a 79-year-old Japanese man, which originated from the subcutaneous tissues of the left upper arm and reached a size of 6 x 5 x 4 cm. Histopathological and electron microscopical findings were compatible with those of benign-type hemangiopericytoma. Magnetic resonance imaging showed the most intense signal on proton density images. Angiography showed the characteristic tumor feeder artery forming a pedicle which entered the tumor and branched radially and a dense, uniform, well-demarcated, oval tumor stain. These images were helpful in performing proper operative treatment without noteworthy bleeding. These modern modalities are excellent non-invasive treatment without diagnostic procedures for the vascular tumors of soft tissues in dermatology.

Aged↗
PubMed1990

DNA adducts formed by 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline in rat liver: dose-response on chronic administration.

The effect of administration of 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) at various doses on DNA adduct formation in male rats was examined by 32P-postlabeling analysis. Administration of MeIQx in the diet at 0.4 ppm, 4 ppm, 40 ppm and 400 ppm for one week resulted in the formations of 0.04, 0.28, 3.34 and 39.0 adducts per 10(7) nucleotides in rat liver cells. Continuous administration of 400 ppm of MeIQx in the diet for 61 weeks to rats induced hepatocellular carcinomas in all rats. The carcinogenicity of MeIQx at doses of 40 ppm or less is not known yet, but the above results show a linear relationship between the level of MeIQx administered and the adduct level. In rats treated with low doses of 0.4, 4 and 40 ppm of MeIQx, adduct levels increased linearly with time of treatment, the levels in week 12 being two to three times those in week 1. In contrast, on treatment with 400 ppm of MeIQx, the adduct level in the liver increased until week 4, when it was 110 adducts per 10(7) nucleotides, and then remained constant for the next 8 weeks. Induction of the multidrug-resistance gene was suggested to be involved in development of this plateau level.

Animals↗
PubMed1990

Ubiquitinated eosinophilic granules in the inferior olivary nucleus.

Ubiquitinated intracytoplasmic eosinophilic granules were found in the inferior olivary neurons of 99 normal individuals. The granules, ranging from 1 to 8 microns in diameter, were round and appeared in groups. Their number increased significantly with ageing. The frequency of the granules in 12 patients with Alzheimer's disease or spinocerebellar degeneration did not differ from that in normal subjects. The ubiquitinated eosinophilic granules can be considered to represent age-related changes in the inferior olivary neurons.

Adult↗
PubMed1990

Peroxidase activity in benign nodular lesions and carcinoma in the rat thyroid induced by N-nitrosobis (2-hydroxypropyl) amine and phenobarbital.

Nodular lesions induced by N-nitrosobis (2-hydroxypropyl) amine (BHP) and phenobarbital (Pb) in F344 rat thyroid were histologically divided into 2 categories, benign lesions and carcinoma. Benign lesions were subclassified into 3 types mainly based on histological characteristics and localization of peroxidase (PO). The type 1 lesion showed localization of PO almost identical with that of the group 1 rat thyroid. Type 2 was characterized by an intense reaction product of PO in the cytoplasm but a weak one on the surface of the microvilli, and type 3 exhibited localization of PO opposite to that of type 2. Carcinoma proliferated in papillary, follicular and poorly differentiated patterns and developed as de novo carcinoma with the highest incidence, although a considerable number of carcinomas coexisted with benign type 3 lesions. A majority of these carcinomas lacked the reaction product for PO. These results suggest that benign nodular lesions, especially types 2 and 3, show hyperactivity of PO synthesis reflecting their response to excessively secreted TSH, whereas carcinoma is autonomous, because of marked inhibition of PO synthesis even in the presence of TSH hypersecretion.

Animals↗
PubMed1990

Effects of dietary iodine on chemical induction of thyroid carcinoma.

Effects of dietary iodine on the induction of thyroid carcinoma using N-nitrosobis(2-hydroxypropyl)amine (BHP) were studied. Male Wistar rats were fed with an iodine-adequate diet (IAD group), an iodine-rich diet (IRD group) and an iodine-deficient diet (IDD group), respectively, until the time of sacrifice. From the 2nd experimental month, animals were injected with BHP once a week for 10 weeks. In the IAD and IRD groups, benign nodules and papillary carcinoma were found. The incidence of rats with benign nodules was 100% in both groups and animals with papillary carcinoma in the IAD and IRD groups comprised 33% and 29%, respectively. The area of the thyroid gland occupied by nodular lesions was much narrower in the IRD group than in the IAD group. In the IDD group, the thyroid showed marked enlargement due to multiple nodular proliferation of follicle cells. The incidence of rats with carcinoma was 100%, and not only papillary but also follicular carcinoma and one pulmonary metastasis were found. As the iodine content of the diet decreased, the nodular lesions increased in width and number, and the incidence of carcinoma in rats became higher. These effects of dietary iodine are probably related to the goitrogenic and/or promoting effects of TSH.

Administration, Oral↗
PubMed1990

Effects of monensin on subcellular structure, thyroglobulin secretion and peroxidase activity of cultured thyroid cells obtained from patients with hyperthyroidism.

The effects of monensin on subcellular structure, release of thyroglobulin (TG) and peroxidase (PO) activity were investigated using primary cultures of thyroid cells obtained from patients with Basedow's disease (Basedow's cells). TG concentration in the culture medium was measured by a sandwich enzyme immunoassay and the amount of TG in cultured cells was measured with an identical sandwich enzyme immunoassay after lysis of the cells with Triton X-100. PO activity of cultured cells was measured by a biochemical method. Addition of TSH (10 mU/ml/day) to the culture medium increased the synthesis and release of TG. When monensin (1 micron/l) was added to the medium on the last day of a 3-day incubation with TSH, the Golgi complex showed vacuolative change ultrastructurally, and the amount of intracellular TG was increased, whereas the amount of TG in the culture medium and PO activity became lower than those in the control group. These results suggest that in cultured Basedow's cells, TG is secreted through the Golgi complex, and that the activity of PO is elevated after processing in the Golgi complex.

Cells, Cultured↗
PubMed1990

Dopamine release via protein kinase C activation in the fish retina.

Calcium-dependent phospholipid-sensitive protein kinase [protein kinase C (PKC)] was partially purified from the carp (Cyprinus carpio) retina through DE 52 ion exchange and Cellulofine gel filtration chromatography. The phorbol ester 12-O-tetradecanoylphorbol 13-acetate (TPA) activated PKC in the nanomolar range. A major 38-kDa protein in the retinal supernatants (105,000 g) was phosphorylated in vitro by PKC during a short period (3 min). Other phosphoproteins also appeared during a further prolonged period (greater than 15 min). Rod-bipolar and dopamine (DA) interplexiform cells in the fish retina were immunoreactive to a monoclonal antibody to PKC (alpha/beta-subtype). The PKC antibody recognized a 78-kDa native PKC enzyme by means of an immunoblotting method. Subsequently, the effects of two kinds of PKC activators were investigated on [3H]DA release from retinal cell fractions containing DA cells that had been preloaded with [3H]DA. A phorbol ester (TPA) induced a calcium- and dose-dependent [3H]DA release during a short period (2 min), with the minimal effective dose being approximately 1 nM. Other phorbols having no tumor-promoting activity, such as 4 beta-phorbol and 4 alpha-phorbol 12,13-didecanoate, were ineffective on [3H]DA release. A synthetic diacylglycerol [1-oleoyl-2-acetylglycerol (OAG)], which is an endogenous PKC activator, was also able to induce a significant release of [3H]DA. Furthermore, TPA was found to release endogenous DA from isolated fish retina by a highly sensitive HPLC with electrochemical detection method. The OAG- or TPA-induced [3H]DA or DA release was completely blocked by inhibitors of PKC, such as 1-(5-isoquinolinesulfonyl)-2-methylpiperazine (H7) and staurosporine.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acids↗