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Biomedical subjects

M Ohshima

Publications and source records attributed to M Ohshima.

At least 91 records · Page 5Linked to original sources
PubMed1991

Analysis of Moloney murine leukemia virus revertants mutated at the gag-pol junction.

Among Moloney murine leukemia viruses (Mo-MuLVs) having stop codons other than UAG at the gag-pol junction, Mo-MuLV with UAA, but not with UGA, had a replication disadvantage. Mo-MuLV with a glutamine codon (CAG) at the junction did not replicate. A revertant of this virus consisted of the original virus and a virus with a deletion of the pol region. Protease and Pr65gag encoded by their respective genomes complemented each other.

3T3 Cells↗
PubMed1991

Immunohistochemical detection of estrogen receptors in paraffin sections of human thyroid tissues.

The optimal demonstration of estrogen receptor binding in thyroid tissues was made under conditions of 10% protease in 50 mM Tris-HCl buffer (pH 7.6) for 10 min as the pretreatment digestion step, incubation of primary antibody (ER-ICA monoclonal kit; Abbott Laboratories) at 37 degrees C for 2 h and incubation of secondary antibody (ABC kit; Vector) at 37 degrees C for 40 min. Thyroid tissues used for assessing the reaction were 17 cases of goiter, 25 adenoma cases, 27 cases of papillary carcinoma, 14 cases of follicular carcinoma and 10 latent cancer cases. Incidences of positive estrogen receptor reaction were 22% (11/51) for all thyroid cancers, 20% (5/25) for the thyroid adenomas and 59% (10/17) for goiters. 15% (4/27) of papillary carcinomas, 21% (3/14) of follicular carcinomas and 40% (4/10) of latent cancers proved positive, the estrogen receptor reaction being limited to the nuclei of thyroid follicular/papillary type cells.

Deoxyribonucleases↗
PubMed1991

CT findings of endobronchial metastasis.

One hundred and sixty-one patients with pulmonary metastases were studied with CT. Six of them proved to have endobronchial (intraluminal) metastatic lesions by bronchoscopy. Retrospective analysis of the CT studies showed obstruction and/or narrowing of the bronchi in 5 cases while no lesion was observed in one patient. Although CT can not always demonstrate intraluminal lesions, it should be performed when an endobronchial metastasis from extrathoracic malignancy is seen by bronchoscopy because it will show hilar or mediastinal lymphadenopathy, or single or multiple pulmonary metastases other than the endobronchial lesion.

Adult↗
PubMed1990

Binding of thyroid hormones to human hemoglobin and localization of the binding site.

Radiolabeled thyroid hormones were allowed to bind to erythrocyte cytosol and the complex was fractionated by Sephadex G-100 or by high-performance liquid chromatography (HPLC). On Sephadex G-100, four radioactive peaks (P1-P4) were obtained, whereas HPLC gave only three radioactive peaks (P1-P3). Chromatographic studies with human adult Hb and non-Hb cytosol protein fractions, which had been reacted with radiolabeled thyroid hormones, and immune precipitation with specific antisera for the hormones, confirmed that the first peak of Sephadex G-100 radioactivity was a mixture of Hb and non-Hb proteins, while the second peak was Hb. The third peak was free 125I and the fourth peak was unbound 125I-T3 or 125I-T4. The third peak of HPLC was confirmed to be a mixture of free 125I and unbound radiolabeled thyroid hormones. Scatchard analysis of the interaction between T4 and apo-Hb, and the alpha- and beta-chains of human Hb suggested the presence of the specific binding site(s) for the hormone. Interaction between T4 and synthesized peptides, which constitute the heme pocket of the beta-chain of Hb (beta 61-75, beta 71-85, beta 81-95), indicated that the T4 binding site of Hb resides within the heme-binding cavity. It is concluded that human erythrocyte cytosol does not contain "receptor" for thyroid hormones and cannot be a model for studying functions of cytosol "receptor" for the hormones; rather, it contains binding protein with large binding capacity, including Hb and non-Hb proteins, which possibly constitute a large reservoir for the hormone in blood.

Binding Sites↗
PubMed1990

Analysis of stress-induced or salicylic acid-induced expression of the pathogenesis-related 1a protein gene in transgenic tobacco.

The cis-acting elements for regulating gene expression of the tobacco pathogenesis-related 1a protein gene were analyzed in transgenic plants. The 5'-flanking 2.4-kilobase fragment from the pathogenesis-related 1a protein gene was joined to the bacterial beta-glucuronidase gene and introduced into tobacco cells by Agrobacterium-mediated gene transfer. Promoter activity was monitored by quantitative and histochemical assay of beta-glucuronidase activity in leaves of regenerated transgenic plants. The level of beta-glucuronidase activity was clearly increased by treatment with salicylic acid, by cutting stress, and by local lesion formation caused by tobacco mosaic virus infection. Cytochemical studies of the induced beta-glucuronidase activity revealed tissue-specific and developmentally regulated expression of the pathogenesis-related 1a gene after stress or chemical treatment and after pathogen attack. To identify the cis-acting element more precisely, a series of 5'-deleted chimeric genes was constructed and transformed into tobacco plants. Transgenic plants with a 0.3-kilobase fragment of the 5'-flanking region of the pathogenesis-related 1a gene had the same qualitative response as those with the 2.4-kilobase fragment upon treatment with salicylic acid or infection with TMV. Thus, the 0.3-kilobase DNA sequence fragment was sufficient to allow the regulated expression of the pathogenesis-related 1a gene.

Base Sequence↗
PubMed1990

Production of monoclonal antibody against human prostatic adenocarcinoma and its immunohistochemical properties.

We have generated a monoclonal antibody against prostatic adenocarcinoma, PC-Ab (IgM) was derived from a fusion using the fresh prostatic tissue of adenocarcinoma as the immunogen. Initial screening was performed by enzyme-linked immunosorbent assay (ELISA) on the soluble fraction of the immunogen. The specific analysis was performed by the avidin-biotin-complex immunoperoxidase method on paraffin-embedded sections of normal, benign and malignant neoplastic tissues from the prostate and various organs. PC-Ab reacted with well differentiated adenocarcinoma (83.3%), moderately differentiated adenocarcinoma (92.2%), and poorly differentiated adenocarcinoma (90.2%), respectively. According to classification by stage, the reaction rates with stage T0, T1, T2, T3 and T4 were 77.3%, 80.0%, 95.2%, 91.3% and 92.9%, respectively but no significant differences in the stages were seen among these groups. PC-Ab reacted with the epithelium of the normal prostate and benign prostatic adenoma, and human fetal tissues. Molecular weight and isoelectric point of the antigen recognized by this PC-Ab was estimated to be 57,000 daltons and 7.0, respectively. These results indicate that PC-Ab reacts with the antigen associated with human prostatic adenocarcinoma.

Adenocarcinoma↗
PubMed1990

[Legionellosis].

Although increasing attention is being given to Legionella pneumonia in Japan, reports of solitary onset of this disease are scant in Japan. The patient, from whom L. dumoffii was isolated, was a 59-year-old male with no underlying disease. He visited our hospital because of fever and cough, and was admitted to our department for X-ray findings consistent with pneumonia. After admission, pulmonary lesions spread rapidly, and based on the suspicion of Legionella pneumonia, drugs such as EM, RFP and MINO were used. However, the patient died on the 26th hospital day. L. dumoffii was isolated from specimens obtained by airway aspiration before death and specimens of lung abscess and airway discharge obtained during autopsy (7 specimens in total). In addition, the L. dumoffii antibody titer in the serum became elevated. This is the first case of L. dumoffii pneumonia reported in Japan. The other case was in an 81-year-old male with underlying disease. He was admitted urgently with suspected pneumonia but died on the following day. L. pneumophila serogroup 5 was isolated from autopsied lung tissue. Fatality is high for this disease, making early diagnosis and treatment with appropriate antibiotics essential. Physicians should bear in mind the possibility of this disease and request the necessary laboratory tests in suspected cases without delay.

Aged↗
PubMed1989

Greater inhibitory effects for testosterone than castration in rat thyroid tumorigenesis initiated by N-bis(2-hydroxypropyl)nitrosamine.

The effects of testosterone and castration on thyroid tumorigenesis subsequent to initiation by N-bis(2-hydroxypropyl)nitrosamine (DHPN) were investigated in male Wistar rats. Following 2 weekly i.p. injections of DHPN at the dose of 210 mg/100 g body weight, testosterone was administered in the diet at concentrations of 0.15% or 0.03% for 28 weeks. Castration was performed on a separate group of animals 1 week after the final injection of DHPN. The incidence of thyroid adenomas and carcinomas were 69% (9/13) and 15% (2/13), respectively, in rats treated with DHPN alone, 0% (0/15) and 6% (1/15) in rats treated with DHPN and 0.15% testosterone, 13% (2/15) and 13% (2/15) in rats treated with DHPN and 0.03% testosterone and 33% (5/15) and 33% (5/15) in the castrated animals initiated by DHPN. The reduction in adenoma development associated with testosterone treatment was significant at both concentrations. In contrast, only a tendency for decrease of thyroid tumor incidence was observed in rats castrated.

Animals↗
PubMed1989

A case of gallbladder cancer manifesting chylous ascites and chylothorax.

A case of gallbladder cancer manifesting both chylous ascites and chylothorax was reported. A 66-year-old man was hospitalized with milky ascites. The patient was diagnosed as having gallbladder cancer based on findings of endoscopic retrograde cholangiopancreatography (ERCP) and celiac angiography. The diagnosis of chylous ascites was confirmed by the presence of microscopically visible free fat and the biochemical analysis of the fluid. The patient also gradually developed chylous thoracic effusion. Autopsy revealed lymphogenous metastasis in multiple retroperitoneal and mediastinal nodes. Chylothorax and chyloperitoneum are relatively rare. Only five cases have been reported in Japan that manifested both conditions.

Adenocarcinoma↗
PubMed1989

Promoting effect of 2,4-diaminoanisole sulfate on rat thyroid carcinogenesis.

Two experiments were conducted to examine the effects of 2,4-diaminoanisole sulfate (2,4-DAAS) on thyroid function and carcinogenesis in male Wistar rats. In experiment 1, feeding with 2,4-DAAS resulted in significantly elevated levels of thyroid stimulating hormone (TSH), reduced thyroxine (T4) and triiodothyronine (T3) in the serum, although the latter had almost recovered to normal levels by week 6. However, skin application did not affect serum levels. In experiment 2, administration of 0.5% 2,4-DAAS in the diet for 19 weeks, a week after a single 210 mg/100 g body weight i.p. injection of N-bis(2-hydroxypropyl)nitrosamine (DHPN), significantly increased the incidence and numbers of preneoplastic lesions (focal hyperplasia), adenomas and carcinomas developing in the thyroid gland. Histologically, brown pigment was usually observed within follicular epithelial cells in non-tumorous regions, but not in the tumors themselves.

Adenoma↗
PubMed1989

Gene amplification and overexpression of EGF receptor in squamous cell carcinomas of the head and neck.

Tumours of the head and neck were examined for gene amplification and expression of the epidermal growth factor (EGF) receptor by Southern blot and Western blot analyses. The EGF receptor gene was found to be amplified in four (19%) of 21 squamous cell carcinomas. The EGF receptor was overexpressed in eight (53%) of 15 squamous cell carcinomas examined, including all four tumours showing gene amplification. No amplification or overexpression of the EGF receptor gene was detected in any of nine malignant or eight benign tumours of other types of the head and neck. The tumours showing amplification and/or overexpression of the EGF receptor gene (8/15) were all identified histologically as well differentiated squamous cell carcinomas, whereas none of the histologically less differentiated squamous cell carcinomas (0/9) showed amplification and/or overexpression of the EGF receptor gene. Within our sample set, no correlation was evident between amplification and/or overexpression and the clinical stage or tumour site. Our results support the possible involvement of gene amplification and overexpression of the EGF receptor in a subclass of squamous cell carcinomas of the head and neck.

Adult↗
PubMed1989

Promotion by sodium barbital of renal cortical and transitional cell tumors, but not intestinal tumors, in F344 rats given methyl(acetoxymethyl)nitrosamine, and lack of effect of phenobarbital, amobarbital, or barbituric acid on development of either renal or intestinal tumors.

Comparative effects of four barbiturates, phenobarbital (PB), amobarbital (AB), sodium barbital (NaBB), and barbituric acid (BA) on the development of neoplasms in the intestinal tract and other organs were investigated in rats following initiation with methyl(acetoxymethyl)nitrosamine (DMN-OAc). Four-week-old F344/NCr male rats were given a single i.p. injection of 0.05 nmol DMN.OAc in 5 ml sterile phosphate buffered saline/kg body weight. Two weeks after DMN.OAc treatment, the animals were provided with either tap water or drinking water containing 500 p.p.m. of PB, NaBB, AB, or BA for the remaining experimental period. Control groups received a single i.p. injection of 5 ml of sterile phosphate buffer/kg body weight and 2 weeks later were given either tap water or drinking water containing 500 p.p.m. of one of the barbiturates listed above. Rats were killed at 52 weeks or 80 weeks after DMN.OAc injection. DMN.OAc induced multiple intestinal tumors that occurred mostly in the mucosa of the small intestine, especially the terminal ileum. None of the barbiturates had any effect on either incidence or multiplicity of intestinal tumors. PB significantly enhanced the development of hepatocellular tumors as well as thyroid follicular cell neoplasms in DMN.OAc initiated rats, while the subsequent administration of NaBB, but not other barbiturates, resulted in the development of renal cortical and pelvic transitional cell tumors. This is the first demonstration of promotion of carcinogenesis in renal pelvic transitional epithelium, a cell type not previously recognized as vulnerable to initiation by DMN.OAc given i.p. NaBB without prior administration of DMN.OAc induced severe nephropathy and focal hyperplasia of both renal cortical tubular and pelvic transitional cell epithelium. No such effects were observed with either PB, AB, or BA. Our results failed to confirm the earlier findings of others that intestinal epithelial carcinogenesis could be promoted by continuous oral administration of NaBB. However, these results strongly support and extend our previous conclusions that some barbiturates have broad organ specificities and promote epithelial carcinogenesis in more than one organ and tissue.

Adenoma↗
PubMed1989

Evaluation of the peri-implant membrane induced around ceramic dental implants in dogs: a transmission electron microscopic study.

A description of the supporting tissues of single-crystal sapphire implants which had functioned for twelve months is reported. The tissue was recovered at autopsy. The peri-implant membrane was formed by the action of mastication forces on the implants and consisted of three non-mineralized connective tissue layers. Layer I was composed of collagen fibers. These fibers were oriented parallel to the implant surface. Layer II lacked collagen fibers. This layer was composed of connective tissue materials. Layer III was covered by osteoclasts or osteoblasts. This layer was composed of collagen fibers which radiated to the bone surface. The collagen fiber bundles did not run from the implant fibers to the bone fibers. This peri-implant membrane formed only a hammock-like supporting mechanism. These findings suggest that the implant had been encapsulated by the peri-implant membrane, which failed to distribute masticulation stress to the peripheral tissues. One year after implantation of single-crystal implants, the tissue-implants interface was observed. Non-mineralized connective tissue layers (a "peri-implant membrane") existed at all implant interfaces. The origin of this structure and the role of a peri-implant membrane are discussed.

Aluminum Oxide↗
PubMed1989

[ATP and ADP of platelets in chronic myeloproliferative disorders and multiple myeloma].

The content of platelet adenine nucleotide in chronic myeloproliferative disorders (CMPD) and multiple myeloma (MM) was measured by a luciferin-luciferase method by Holmsen and Weiss. The release of ATP and ADP from platelet during aggregation induced by collagen and epinephrine were analyzed. The total 42 investigated cases consisted of 11 cases of polycythemia vera (PV), 7 cases of essential thrombocythemia (ET), 7 cases of chronic myeloid leukemia (CML), 9 cases of blastic crisis of CML (BC-CML), and 8 cases of multiple myeloma (MM). The healthy control was 19 cases. In CMPD and MM, the amount of ATP was normal in spite of decrease of ADP; therefore, the ratio of ATP/ADP increased. On the other hand, the ATP significantly increased in BC-CML. MM revealed a remarkable increase of ATP release due to the aggregation by collagen and epinephrine. The maximal rate of aggregation of collagen and epinephrine using Lumi-aggregometer indicated a positive relationship with the ATP release by the Holmsen and Weiss' method. The platelet volume in CMPD increased showing correlation with ATP content and not with ADP. In conclusion, CMPD and MM are regarded as acquired qualitative disorders of platelets or secondary storage pool diseases from the view points of the abnormalities in ATP, ADP contents and their release. However, BC-CML and MM revealed some different change from that of CMPD.

Adenosine Diphosphate↗
PubMed1989

Effects of postnatal administration of tumour-promoting barbiturates on the development of tumours initiated by prenatal exposure of fetal rats and mice to N-alkylnitrosoureas.

Prenatal administration of chemical carcinogens followed by postnatal application of tumour promoters can result in tumour formation at sites where no tumours would occur in the absence of promotion. Three different epithelia in mice and rats have been shown to be susceptible to transplacental initiation by N-nitroso compounds or polynuclear aromatic hydrocarbons, yielding potentially neoplastic cells in fetal tissues which can remain latent indefinitely until stimulated to proliferate by postnatal exposure to a promoting agent. These include epidermal squamous epithelium in mice, renal cortical epithelium in mice, and thyroid follicular epithelium in both mice and rats. The fact that effective promoters of carcinogenesis in nonsquamous epithelia include drugs such as phenobarbital that are administered to humans in high doses for prolonged periods suggests that prenatal initiation followed by postnatal promotion may pose significant risks for humans, and should be considered in designing epidemiological searches for etiological factors that contribute to the incidence of epithelial tumours in man.

Aging↗