Biomedical subjects

M Asahi

Publications and source records attributed to M Asahi.

At least 91 records · Page 5Linked to original sources

PubMed1994

A case of cutaneous infection by Exophiala jeanselmei.

A case of cutaneous infection by Exophiala jeanselmei is reported. The patient was a 45-year-old Japanese female. Her skin eruption consisted of a group of erythematous papules on her left cheek to which corticosteroid had been topically applied for nearly 10 years. Histopathologically, a granuloma formation was noted in the dermis within which were many brown spores. The isolated fungus was identified as Exophiala jeanselmei.

Dermatomycoses↗

PubMed1993

Activation of protein-tyrosine kinase p72syk with concanavalin A in polymorphonuclear neutrophils.

We studied the abundance, subcellular distribution of a non-receptor protein-tyrosine kinase p72syk (Taniguchi, T., Kobayashi, T., Kondo, J., Takahashi, K., Nakamura, H., Suzuki, J., Nagai, K., Yamada, T., Nakamura, S., and Yamamura, H. (1991) J. Biol. Chem. 266, 15790-15796) in porcine polymorphonuclear neutrophils and the activation upon the stimulation with concanavalin A. The abundance was about 0.1% of total proteins and mainly distributed in the particulate fraction. Upon concanavalin A stimulation, the activity of p72syk increased within 30 s, attained to the maximum level at 1 min, and then returned to the basal level within 6 min. This activation was observed in a dose-dependent manner and abrogated by simultaneous addition of methyl alpha-mannopyranoside. When both extra- and intracellular Ca2+ were depleted, the activation of p72syk was still persistent; in contrast, the deactivation process was completely abrogated even at 6 min after stimulation. The replenishment of Ca2+ in the presence of A23187 resulted in a similar deactivation pattern as seen in the Ca(2+)-rich condition. In addition, genistein and herbimycin A, potent protein-tyrosine-kinase inhibitors, were capable of reducing concanavalin A-evoked p72syk activation and Ca2+ mobilization as well as the aggregation and lysozyme release. Furthermore, A23187-induced Ca2+ accumulation in inhibitor-treated cells resulted in the restoration of those cellular responses. These lines of evidence suggest that p72syk is activated with concanavalin A in a Ca(2+)-independent manner, participating in a mechanism of Ca2+ recruitment, and negatively regulated by a feedback mechanism through Ca2+ in neutrophils.

Animals↗

PubMed1993

[Clinical features and pathogenesis of Yusho (PCB poisoning)].

The occurrence and progress of Yusho (PCB mass poisoning) is briefly described. Various investigative studies on Yusho are also briefly reviewed. Yusho occurred in the northern district of Kyushu Island in 1968. A specific product of rice oil used for food was accidentally contaminated with PCB during its manufacturing process and consequently, the customers who ate it showed severe intoxication symptoms. Major clinical symptoms of Yusho were acneiform eruptions and circumscribed pigmentation. These skin and mucous membrane eruptions, because of their appearance, caused severe mental suffering for the patients. The government-authorized patients amounted to 1,860. These symptoms have gradually declined with the passing of years and presently the principal clinical problems are only various subjective complaints. At first, it was naturally thought that the causative agent of Yusho was PCB (Kanechlor 400) itself. However, it was found later that the causative rice oil contained PCDF (polychlorodibenzofuran) and PCQ (polychloroquaterphenyl) which were proved to be formed during the heating process used in the deodorization of the oil. PCDFs show, in animal studies, a high toxicity and therefore its role for the pathogenesis of Yusho is seriously evaluated in spite of its rather small contaminating amount. On the other hand, PCQs are recognized as the specific marker of Yusho, since almost no PCQ is a general environmental pollution substance.

Animals↗

PubMed1993

Protein-tyrosine kinase p72syk is activated by thrombin and is negatively regulated through Ca2+ mobilization in platelets.

Activation of platelets by thrombin results in a dramatic increase in tyrosine phosphorylation on multiple cellular proteins (Ferrell, J. E., and Martin, G. S. (1988) Mol. Cell. Biol. 8, 3603-3610; Golden, A., and Brugge, J. S. (1989) Proc. Natl. Acad. Sci. U. S. A. 86, 901-905; Nakamura, S., and Yamamura, H. (1989) J. Biol. Chem. 264, 7089-7091). However, none of the responsible protein-tyrosine kinase has been reported so far. We report here that p72syk, one of the non-receptor-type protein-tyrosine kinases, is activated following thrombin stimulation in blood platelets. Washed porcine platelets were stimulated by thrombin, and the activation of p72syk was assessed in an immunoprecipitation kinase assay. The activity of p72syk increased within 5 s, reached a maximum at 10 s, and decreased to a basal level within 60 s after 0.5 unit/ml thrombin stimulation. The amount of immunoprecipitated p72syk was not altered throughout the time course. This activation was greatly enhanced in a dose-dependent manner and was completely canceled by the pretreatment of platelet suspension with hirudin, a specific antagonist of thrombin. In the Ca(2+)-depleted condition both extra- and intracellularly, the activation of p72syk was still persistent; in contrast, the deactivation process was completely abrogated even at 120 s after thrombin stimulation. In addition, the replenishment of Ca2+ resulted in a similar deactivation pattern as seen in the Ca(2+)-rich condition. Furthermore, this deactivation was also canceled by the pretreatment of platelets with W7, a calmodulin antagonist, as well as ML9, a myosin-light-chain kinase inhibitor. These results indicate that p72syk can be a responsible enzyme to the protein-tyrosine phosphorylation events following the platelet activation by thrombin and may be negatively regulated by Ca2+ in a calmodulin-dependent manner, inter alia myosin light-chain kinase, in thrombin-stimulated platelets.

Animals↗

PubMed1993

A combined occurrence of neuroendocrine carcinoma of the skin and a benign appendageal neoplasm.

A 76-year-old Japanese male presented with a subcutaneous nodule in the dorsal cubital region of the right arm. The center of the nodule showed typical features of neuroendocrine carcinoma of the skin. The peripheral portion showed epithelial islands of squamoid cells with horn cysts suggestive of benign appendageal tumor with pilar differentiation. The coexistence of two skin neoplasms in the same lesion would suggest that both tumors developed from common pluripotential stem cell.

Aged↗

PubMed1993

A unique case of apocrine carcinoma on the male pubic skin: histopathologic and ultrastructural observations.

We report a case of cutaneous adenocarcinoma on the pubic region of a 56-year-old male. The exophytic tumor showed solid, ductal, and glandular patterns with decapitation secretion and mucinous carcinoma-like nests. Despite the exophytic nature of the lesion, an invasive growth pattern into the deep dermis and subcutaneous fat was seen. An additional characteristic of this tumor was the presence of Paget's phenomenon. From these findings, we conclude that this tumor is an apocrine adenocarcinoma having an unusual clinical appearance and unique histopathological features which have some similarities to apocrine carcinoma of the breast and some to syringocystadenoma papilliferum and nipple adenomatosis.

Adenocarcinoma↗

PubMed1993

Thoracic mobile neurinoma. Case report.

The authors report a rare case of intraspinal thoracic mobile neurinoma in a 51-year-old man. The clinical symptoms, especially thoracoabdominal discomfort, changed remarkably according to the patient's posture. Magnetic resonance images demonstrated that the level of the caudal end of the tumor varied between T4-5 and T9-10 with changes in the patient's position. Intraoperative myelography was useful in identifying the tumor location and choosing the level of the laminectomy.

Humans↗

PubMed1993

[Dermatological findings in the annual examination of the patients with Yusho in 1991-1992].

We reported the skin symptoms and PCB concentrations of the patients with Yusho in the 1991 and 1992 annual examinations. We also reported the alteration of the skin symptoms in 20 patients followed up for 16 years (1977-1992). Most of the patients examined in 1991-1992 showed low score of skin symptoms which are the same as those in recent 7 years. Approximately 30% of the patients still have comedones and/or acneiform eruptions in 1991-1992. Pattern and concentrations of PCB in the patients have not remarkably changed in recent 5 years.

Female↗

PubMed1993

[Long-term follow up of trigeminal neuralgic patients treated by retrogasserian rhizotomy or by microvascular decompression].

The authors studied the long-term follow up of trigeminal neuralgic patients treated by retrogasserian rhizotomy with anhydrous glycerol injection (GI) or by microvascular decompression (MVD) and compared the satisfaction rates between them. Since 1983, 67 patients had been treated either by GI or MVD. The authors analyzed the results of the treatment by the method of questionnaire. Fifty-two patients of these 67 answered the questions, on which the present analysis was based. GI group consisted of 27 patients and MVD group 29 patients. The average follow-up period was 30.9 months in GI group (maximum follow-up: 84 months) and 50.9 months in MVD group (maximum follow-up: 95 months), respectively. The technique of GI used was Härtel's method with cisternography of Meckel's cave. The operations of MVD were performed by J.H. and A.K.. One patient out of 29 failed to be treated by MVD and two recurred within one year. On the other hand, 2 patients out of 27 failed to be treated by GI and 11 recurred. The recurrence was seen earlier in patients who had undergone GI, while one patient recurred the neuralgia at 76 months later. The recurrence rate in patients treated by MVD is 7.0% at 95 months, while that by GI is 49.0% at 84 months based on Kaplan-Meier survival analysis. The pathogenesis of trigeminal neuralgia is speculated to be an emphatic conduction caused by segmental demyelination and artificial synapse formation at the junction of central and peripheral myelin. The factors of this demyelination may be multiple sclerosis, basilar impression, aneurysm, arteriovenous malformation, atheroscleroses and natural aging.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1993

[Dumbbell cervical neurinomas with subcutaneous extension: report of two cases].

Two cases of dumbbell cervical neurinomas with massive subcutaneous extension were reported. The first case was A 30-year-old woman who was admitted to our hospital because she had been aware of a left lateral cervical subcutaneous mass and was suffering from shoulder dullness. On admission, neurological examination revealed hypesthesia to touch and pain in the segmental area of C4, and hyperreflexia in the left biceps and patellar tendon reflexes. Plain X-ray showed enlargement of the left C3/4 intervertebral foramen. CT scan, post-myelogram CT and MRI demonstrated a dumbbell shaped tumor at the level of C3-4. Angiogram showed an anterior shift of the left vertebral artery (VA) and tumor stain. Temporary occlusion of the left VA by a balloon catheter was performed leaving no neurological deficits. The second case was a 36-year-old woman who had been aware of a left lateral cervical subcutaneous mass. She complained of shoulder pain and finger clumsiness. On admission, neurological examination revealed weakness of the left deltoid muscle, hypesthesia in the segmental area of C3-4 and exaggeration of all deep tendon reflexes in the left-side extremities. Plain X-ray showed enlargement of the C2/3, C3/4 and C4/5 intervertebral foramina. CT scan, post myelogram CT and MRI demonstrated a dumbbell shaped tumor at the level of C2-5. Angiogram showed an anteromedial shift of the left VA and tumor stain. Temporary occlusion test of the left VA by a balloon catheter was performed with negative results. In each case two-stage operations were undertaken with excellent results.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1992

Thrombin-induced human platelet aggregation is inhibited by protein-tyrosine kinase inhibitors, ST638 and genistein.

We have investigated the involvement of protein-tyrosine kinases in thrombin-induced aggregation of human platelets, using ST638 and genistein which are known inhibitors of protein-tyrosine kinase. Preincubation of platelets with 50 microM of ST638 or 25 micrograms/ml of genistein completely blocked the platelet aggregation induced with 0.05 unit/ml of thrombin. The increase of protein-tyrosine phosphorylation bands (135-, 124-, 76-, 64-, and 60-kDa) induced with thrombin was also inhibited by these inhibitors in a dose-dependent manner. These inhibitors also blocked the platelet aggregation and protein-tyrosine phosphorylation induced with thrombin in aspirin-treated platelets. Increase of the intracellular Ca2+ concentration induced by thrombin was also inhibited by higher concentrations of genistein. These results suggest that the protein-tyrosine phosphorylation plays a certain role in platelet activation having some relation to the intracellular Ca2+ concentration.

Amino Acid Sequence↗

PubMed1992

Protein-tyrosine kinase p72syk is activated by wheat germ agglutinin in platelets.

We previously reported a molecular cloning of porcine gene syk encoding a non-receptor type 72-kDa protein-tyrosine kinase (Taniguchi et al. (1991) J. Biol. Chem. 266, 15790-15796). In this study, we have demonstrated that p72syk is expressed in porcine platelets at 0.1-0.2% of total protein and that the lectin wheat germ agglutinin induces an activation of p72syk against both auto- and exogenous-substrate-phosphorylation in porcine platelets. The activation of p72syk was abrogated by the coexistence of N-acetyl-D-glucosamine with wheat germ agglutinin. These data suggest that p72syk is a candidate of responsible protein-tyrosine kinase for platelet activation and that cell surface glycoprotein is involved in the activation of p72syk in platelets.

Acetylglucosamine↗

PubMed1992

A histopathological and ultrastructural study of eccrine porocarcinoma with special reference to its subtypes.

Five cases of eccrine porocarcinoma were studied by light and electron microscopy. Histopathologically, these could be classified into two types; the common and the giant cell type. The common type was characterized by almost uniform medium-sized cuboidal tumour cells and a formation of well-developed intracytoplasmic lumina. A broad diversity of histopathological and ultrastructural features was seen in these tumours. The tumours of the giant cell type consisted of mononuclear polygonal cells and bizarre giant cells. This type was considered to be an undifferentiated form of porocarcinoma.

Adenoma, Sweat Gland↗

PubMed1992

Glial cyst of the pineal gland with characteristic computed tomography, magnetic resonance imaging, and pathological findings: report of two cases.

Two cases of glial cyst of the pineal gland are documented. Preoperative computed tomography and magnetic resonance imaging revealed cystic lesions of the pineal region with contrast enhancement of the walls, suggesting neoplastic lesions rather than true cysts. However, the histopathological examination of the resected specimens revealed the presence of glial tissue and normal structure of pineal gland and capsule, characteristics that were consistent with those of glial cysts of the pineal gland. Headache and visual disturbance were resolved after total removal of the cysts.

Adolescent↗

PubMed1992

Sweat gland carcinoma with mucinous and infiltrating duct-like patterns.

We report a rare case of mucinous carcinoma of the skin with mammary infiltrating carcinoma-like patterns. An 82-year-old Japanese male had a gourd-shaped tumor on his scalp. Histopathologically, the posterior portion of the tumor showed small lobules of cuboidal tumor cells with no atypia floating in mucinous lakes. In the anterior portion, there were solid lobules, cords, and strands of anaplastic tumor cells infiltrating into the surrounding stroma. Enzyme- and immunohistochemistry and electron microscopy confirmed the eccrine origin of this tumor. It is suggested that mucinous carcinoma of the skin can occur in association with diverse histological patterns, analogous to mucinous carcinoma of the breast.

Acid Phosphatase↗

PubMed1991

Identification of the phosphorylation sites of H2B histone by a catalytic fragment of p72syk from porcine spleen.

Phosphorylated sites of calf thymus H2B histone were investigated with a catalytic fragment of 72 kDa protein-tyrosine kinase (p72syk). Three of five tyrosine residues in H2B histone can be phosphorylated by this kinase. In this analysis, H2B histone was thoroughly phosphorylated in vitro with [gamma-32P]ATP and the kinase, and then digested with a lysylendopeptidase. The resulting radioactive phosphopeptides were separated by a reverse-phase column on high performance liquid chromatography. Subsequent sequential Edman degradation of the purified phosphopeptides revealed that 40Y, 83Y and 121Y were phosphorylated. 121Y is the major phosphorylated residue in H2B histone. No phosphorylation was detected in 37Y and 42Y. Although the consensus sequence was not defined from these analyses, our data suggest that higher-order structure(s) in addition to primary one may participate in recognition of H2B histone by this protein kinase.

Amino Acid Sequence↗

PubMed1991

Possible endogenous substrate proteins for cytosolic protein-tyrosine kinase from porcine spleen.

1. Endogenous phosphate acceptor proteins by cytosolic protein-tyrosine kinase from porcine spleen (CPTK-40) were studied using subcellular fractions of porcine spleen and supernatant fraction of rat various tissues. 2. At least 13 phosphate acceptor proteins ranging from 94 to 26 kDa were observed in all but mitochondrial subcellular fractions. 3. Among the supernatant fraction of rat tissues, brain, testis and spleen contained many phosphate acceptor proteins. 4. The most heavily phosphorylated band of around 55 kDa which was commonly recognized among various tissues was confirmed as tubulin by the immunoreactivity with anti-tubulin antibody. 5. The results obtained in this paper indicate that CPTK-40 has the potential to catalyze the phosphorylation of numerous endogenous proteins including tubulin.

Animals↗

PubMed1991

Medusa head-like granules in squamous cell carcinoma with differentiation toward a hair follicle structure.

A case of squamous cell carcinoma (SCC) with regional lymph node metastasis in a 69-year-old Japanese man is reported. The tumor was characterized by the proliferation of peripheral basaloid, inner squamoid, and glycogen-rich cells, the presence of trichilemmal keratinization, and the presence of ladder-like, membrane-coating granules. These findings suggested that this tumor differentiates toward a hair-follicle structure. The most interesting feature of this tumor was the presence of medusa head-like granules in the cytoplasm of the clear squamoid cells adjacent to the keratinized cells. We have been unable to find any other studies of these granules in squamous cell carcinoma.

Aged↗