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Biomedical subjects

M Terada

Publications and source records attributed to M Terada.

At least 379 records · Page 21Linked to original sources
PubMed1991

Detection of frequent p53 gene mutations in primary gastric cancer by cell sorting and polymerase chain reaction single-strand conformation polymorphism analysis.

Mutations of the p53 gene were investigated after tumor cell enrichment by cell sorting based on differences in DNA content and polymerase chain reaction single-strand conformation polymorphism analysis in 24 surgical specimens of primary gastric cancer. p53 mutations were detected in exons 4-8 in 64% (9 of 14) of aneuploid tumors but in none of 10 diploid tumors examined. Four of five tumors containing two or three aneuploid subpopulations showed the presence of p53 gene mutations. No correlation was found between the presence of p53 mutations and the degree of histological differentiation of tumors. These findings suggest that p53 gene mutations are related to DNA ploidy alterations as relatively late events of carcinogenesis in gastric cancer. The present method is highly sensitive for detection of genetic abnormalities and is applicable even when various kinds of nontumorous cells are present in tumor samples.

Base Sequence↗
PubMed1991

Structural analysis of a mature hst-1 protein with transforming growth factor activity.

A recombinant hst-1 protein produced in silkworm cells by a recombinant baculovirus, previously shown to be a potent mitogen for NIH3T3 cells and human endothelial cells, also stimulated anchorage-independent growth of NRK-49F cells. Amino acid sequence analysis revealed that the amino-terminal sequence with 58 amino acids was cleaved off in silkworm cells. These results indicated that the mature hst-1 protein consisting of 148 amino acids had transforming growth factor activity.

Amino Acid Sequence↗
PubMed1991

Molecular cloning and characterization of a new subtype of human papillomavirus 6 DNA.

A new subtype of human papillomavirus (HPV) 6 was molecularly cloned from a laryngeal papilloma specimen. The DNA of this isolate showed a strong hybridization signal with HPV 6b DNA under stringent conditions. Comparison of restriction enzyme fragment patterns of this HPV DNA with HPV 6b DNA revealed that this DNA is not identical to HPV 6b DNA. Thus, it represents a new subtype of HPV 6 DNA, which we have tentatively designated as HPV 6e DNA. A map of the physical structure of HPV 6e was also established.

Adolescent↗
PubMed1991

Hashimoto's thyroiditis presenting with severe pressure symptoms--a case report.

A extremely rare case of Hashimoto's thyroiditis presenting with pressure symptoms is described herein. A 50 year old Japanese woman was referred to our department with swelling of the anterior neck, facial edema and recent heavy snoring. Oto-rhinolaryngological examinations revealed no movement of the bilateral vocal cords, severe laryngeal edema and diffuse edema of the tongue and pharynx. These findings had apparently been induced by compression of the bilateral recurrent nerves and internal jugular veins by an enlarged thyroid gland. The results of thyroid function and autoimmune tests were compatible with a diagnosis of Hashimoto's disease and thus, total thyroidectomy with a tracheostomy was performed uneventfully. The resected specimen weighed 168 grams and was confirmed histologically to be Hashimoto's disease. Following her operation, all the above symptoms disappeared and 4 months later, the patient is well and asymptomatic.

Cranial Nerve Diseases↗
PubMed1991

Resistance to anticancer drugs in NIH3T3 cells transfected with c-myc and/or c-H-ras genes.

NIH3T3 cells transfected with c-H-ras and/or c-myc genes were examined for differences in drug sensitivity. The five transfectants used were N8, NIH3T3-nm-1, pT22-3-nm-2, pP1-4 and pT22-3. They were transfected with pKOneo alone, pKOneo and c-myc, pKOneo and c-myc plus activated c-H-ras, normal c-H-ras and activated c-H-ras genes, respectively. The IC50s of cisplatin, 4-hydroperoxycyclophosphamide, adriamycin, melphalan, and CPT-11 were significantly higher for NIH3T3-nm-1 abd pT22-3-nm-2 than for the parental NIH3T3 and N8 cells. Transfection with normal and activated C-H-ras oncogenes only led to increases in the IC50s of alkylating agents. There was no significant difference between the IC50s of N8 and those of NIH3T3 parental cells to any of these anticancer agents. These results strongly suggest that the expression of the c-myc gene plays a role in the acquisition of drug resistance. The c-myc gene may therefore provide us with an important clue in determining the mechanism of drug resistance.

Animals↗
PubMed1991

Shaking HIV-1 infected cells indicates novel behavior of MN strain.

The shaking method of harvesting human immunodeficiency virus type 1 (HIV-1) is a powerful method of obtaining high titer, highly infective virus solutions. In this method infected cells are suspended in a small volume of liquid and the mixture is shaken. Viral infectivity, measured by tissue culture infective dose (TCID50) studies, rises faster than virus titer, as measured by reverse transcriptase levels. It is postulated that this disproportionate increase in infectivity results from improved infectivity for the virus particles obtained from shaking the infected cells. Of the five strains of HIV-1 studied (IIIB, AL1212, 906, RJ4029, and MN), one strain, MN, behaved differently than the others. Upon shaking, its virus titer increased 18-fold, as opposed to the 5-10 fold increase demonstrated by the other strains. These results may indicate that MN virions are retained more on the surface of the infected cells, rather than budding off into the surrounding medium, than other HIV-1 strains. In support of this theory it was found that ratios of immunofluorescence assay scores to reverse transcriptase levels were higher for MN than for other strains.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Newly established uterine cervical carcinoma cell line with co-amplification of human papillomavirus DNA and c-myc gene.

A new human tumor cell line, NCC-c-CX-1 (CX-1), was established from a uterine cervical cancer xenografted in nude mice. This cell line harbored approximately 50 to 100 copies of human papillomavirus (HPV) type 18 DNA per haploid genome, and contained about 16-fold-amplified c-myc gene with rearrangement. These genomic alterations found in CX-1 cells were also present in both primary tumor and xenografted tumor. Histopathologically, original and xenografted tumors were poorly differentiated cancer and were characterized by neuroendocrine features such as positive neuron-specific enolase and chromogranin A by immunohistochemistry and abundant neurosecretory-type granules in the cytoplasm by electron microscopy. However, the established cell line had lost the neuroendocrine features. This cervical cancer cell line may be a useful model for studying cervical carcinogenesis, especially the interaction between HPV and c-myc oncogene.

Adult↗
PubMed1991

Point mutation of c-Ki-ras oncogene in gastric adenoma and adenocarcinoma with tubular differentiation.

The presence of point mutation at codons 12, 13 and 61 of the c-Ki-ras oncogene was investigated in 7 cases of gastric adenoma and 35 cases of gastric adenocarcinoma using DNA samples from formalin-fixed and paraffin-embedded tissues. Oligonucleotides encompassing the three codons were amplified by using the polymerase chain reaction (PCR), and then examined for point mutation by the selective oligonucleotide hybridization technique. Point mutation was detected in three of the 7 adenomas (43%) and three of the 35 carcinomas (9%). All the gastric adenomas showed the histology of tubular adenoma, being very similar to that of colonic adenoma. The 35 cases of gastric adenocarcinoma were classified into 17 cases of differentiated type and 18 cases of undifferentiated type including signet-ring cell carcinoma. The point mutation of c-Ki-ras oncogene was detected only in the differentiated type (3/17, 18%), and there was no case with point mutation in the undifferentiated type. These results suggest that the genetic mechanism of carcinogenesis differs between the differentiated type and the undifferentiated type of gastric adenocarcinoma, and also that c-Ki-ras activation is possibly involved in a relatively early step of the "adenoma-carcinoma sequence," which leads to the development of a portion of differentiated adenocarcinomas in the stomach.

Adenocarcinoma↗
PubMed1991

Purification and characterization of human papillomavirus type 16 E7 protein with preferential binding capacity to the underphosphorylated form of retinoblastoma gene product.

Human papillomavirus type 16 E7 is considered to be a major viral oncoprotein playing an important role(s) in cervical cancers. E7 protein was shown to bind to the protein product of the retinoblastoma gene (RB), while simian virus 40 large T and adenovirus E1A were also shown to possess binding activity to RB protein. The RB protein is a cell cycle regulator that is highly phosphorylated specifically in S, G2, and M, whereas it is underphosphorylated in G0 and G1. Recently, large T was demonstrated to bind preferentially to the underphosphorylated RB protein, which is considered to be an active form restricting cell proliferation. However, it is not known whether E7 can bind to phosphorylated RB protein. We successfully purified large quantities of unfused human papillomavirus type 16 E7 protein expressed in Escherichia coli by using a T7 promoter-T7 RNA polymerase system. The purified E7 protein was demonstrated to bind preferentially to the underphosphorylated RB protein.

Amino Acid Sequence↗
PubMed1991

Chromosomal localization of putative tumor-suppressor genes in several human cancers.

Restriction-fragment-length polymorphism analysis was performed on several different types of human cancers, including carcinoma of the uterine cervix, neuroblastoma, hepatocellular carcinoma, pheochromocytoma, stomach cancer, and small-cell lung carcinoma (SCLC), to determine the chromosomal loci of putative tumor-suppressor genes in each type of tumor because less of heterozygosity (LOH) is supposed to unmask the recessive mutation of tumor-suppressor gene in the remaining allele. Chromosomal loci showing frequent LOH differed among these tumors, suggesting that there are several tumor-suppressor genes in the human genome and that critical genes for the development of each type of tumor are different. In some cases LOH was observed in the early stage of tumor such as chromosome 3p loss in carcinoma of the uterine cervix, and in other cases it was observed only in the advanced stage of tumor such as chromosomes 4 and 16q loss in hepatocellular carcinoma. These results suggest that there are two different types of tumor-suppressor genes: one is the gene whose inactivation is responsible for malignant transformation of a normal cell and the other is the gene whose inactivation is responsible for the progression of a tumor cell. In SCLC, LOH at three different chromosomal loci, 3p, 13q, and 17p, was simultaneously observed in nearly 100% of tumors. It was observed even in stage I tumors and an untreated tumor, and it occurred prior to N-myc amplification. These results may imply that at least six genetic alterations are necessary to convert a normal cell into a fully malignant cancer cell in SCLC.

Alleles↗
PubMed1991

Central effects of yohimbine on copulatory behavior in aged male rats.

It is well known that yohimbine has a history of popular use because of its supposed aphrodisiac properties. The present study was done to determine whether yohimbine can modify the copulatory behavior of aged male rats. Adult male rats of the Wistar-Imamichi strain, 52 weeks of age and weighing 600-650g, were injected intracerebroventricularly with yohimbine hydrochloride (5, 10 micrograms/10 microliters/rat) or vehicle. Each male was then given the opportunity to mate with a receptive female for 30 min after administration of yohimbine or vehicle. Yohimbine produced significant decreases in the latency to initial mounting and significant increases in the number of mountings. However, there was no ejaculation in the yohimbine-and vehicle-treated males. This study is the first to clearly establish an important modulator of sexual arousal for yohimbine in aged male rats.

Aging↗
PubMed1991

Effects of methamphetamine on copulatory behavior in male rats.

Many papers have reported the effect of amphetamine and its close relative, methamphetamine on sexual activity in humans. The effect of these drugs on animal sexual behavior is unknown. The present study was done to determine whether methamphetamine modifies the copulatory behavior of male rats. Sexually experienced rats of the Wistar-Imamichi strain, 10 weeks of age, were singly injected intraperitoneally with methamphetamine hydrochloride at doses of 0, 1, 2 or 4 mg/kg body weight. Tests were initiated at 19: 30 in the dark period. Observations were conducted for 90 min. At dosages of 1 or 2 mg/kg there were no changes in copulatory behavior ascribed to the administration of methamphetamine. At 4 mg/kg the frequencies of mounting, intromission and ejaculation were greatly decreased but the spontaneous motor activity and stereotypic behavior increased in all males. In a further experiment, males were given methamphetamine by intraperitoneal injection once a week for 8 weeks. The copulatory behavior was tested 5 times at two weeks intervals. In the 4th testing, the percentage showing ejaculation decreased. In the 5th testing, there was no ejaculation and the incidence of intromission decreased. No stereotypic behavior was displayed in any of the males during the testing. From these results, it was concluded that methamphetamine inhibits the intromitting and ejaculating behavior in male rats.

Animals↗
PubMed1991

[Fontan type procedure in patient with borderline hemodynamics: using a temporary R-L shunt in early postoperative period].

Fontan type procedure was successfully performed to a 14-year-old patient with borderline hemodynamics using a temporary R-L shunt in early post operative period. Preoperative diagnosis was DORV (ILD), small RV, PS, ASD, juxtaposition of atrial appendages and post bilateral B-T shunts. Preoperative catheterization studies showed low PARI but insufficient pulmonary arterial size (PA-index 220). In the Fontan procedure, RA was partitioned obliquely with a composite patch of xenograft and Dacron velour. A 5.5 mm hole was created only in xenograft to allow a temporary R-L shunt. During rewarming period, systemic pressure hovering around 60 mmHg with 10 micrograms/kg/min of dopamine and dobutamine. Then a R-L shunt was created by a side to side anastomosis between the appendages with the orifice diameter of 10 mm, followed by a rise in the systemic pressure up to about 80 mmHg. One post operative day, a readjustable occluder was applied at the site of appendage anastomosis to control R-L shunt flow. According as CVP decreased, the occluder was tightened up step by step. Finally, the occluder was fully tightened up in 10 post operative days. This experience suggests that a temporary R-L shunt in early post operative period may be applicable in patient with borderline hemodynamics for Fontan type procedure.

Adolescent↗
PubMed1991

[A statistical investigation of the influence of allergic factors on intractable asthma by multiple factor analysis].

The relationships of the development of intractability in bronchial asthma with 11 factors, namely 1) sex, 2) age of onset, 3) duration of the disease, 4) severity of the disease, 5) disease type, 6) family history within the third degree of consanguinity, 7) history of smoking, 8) history of atopic dermatitis, 9) history of allergic rhinitis, 10) history of chronic sinusitis and 11) history of nasal polyp were studied by multiple factor analysis in 95 patients. The severity of the disease was shown to be the most important factor in whether the disease becomes intractable or not, followed by the age of onset. The history of atopic dermatitis had the least influence, and the influences of the other factors were not markedly different from one another. Evaluation of each factor according to the category score suggested that severe or moderate non-atopic bronchial asthma in males with a positive family history and positive histories of smoking, chronic sinusitis, nasal polyp and atopic dermatitis within a short period after the onset in the second decade or fifth decade or later tend to become intractable.

Adolescent↗
PubMed1991

Biological significance of gene amplification in carcinogenesis.

K-SAM gene was originally isolated as an amplified gene in a stomach cancer cell line by in-gel DNA renaturation method. K-SAM encodes a membrane receptor with tyrosine kinase and is often amplified in poorly differentiated type of stomach cancer, while c-ERBB-2 is often amplified in well differentiated type of stomach cancer. There are several forms of K-SAM mRNAs which are generated by alternative splicing, and two types of K-SAM protein without transmembrane region. The ligand of K-SAM is considered to be growth factor(s) belonging to fibroblast growth factor (FGF) or heparin binding growth factor (HBFG) family. We have also frequently found amplification of HST-1 or HSTF1 gene in esophageal cancer. HST-1 gene, originally found as a transforming gene, is located on human chromosome 11q13, and it locates 35 kbp apart from its related gene, INT-2. Neither of the genes was expressed even in cancer cells with the co-amplification. By cosmid walking, we have identified at least two genes, designated tentatively as EXP1 and EXP2, on the same amplicon as HST-1 and INT-2, and the mRNAs for EXP1 and EXP2 genes were increased in amounts proportional to the degree of amplification.

Esophageal Neoplasms↗