[Genetic screening for novel genes by insertional mutagenesis with gene trap method in ES cells].
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Animals↗
Biomedical subjects
K Yamamura
Publications and source records attributed to K Yamamura.
[A case report of pulmonary sequestration (Pryce I) associated with incomplete lobulation of the left lung].
A 28-year-old man was treated surgically for pulmonary sequestration of Pryce type I associated with incomplete lobulation of the left lung. His chief complaint was hemoptysis. His chest X-ray film showed a mass lesion behind the cardiac shadow. Aortogram revealed a large artery arising from the descending aorta and supplying the left basal segment, and venous blood returning into the left inferior pulmonary vein. The left basal segment had no pulmonary arteries. A bronchogram showed no defects in the bronchial tree. The left basal segment was resected successfully. Histological study showed the trunk of the aberrant artery to be elastic. Differences between histological types of aberrant arteries in pulmonary sequestration of Pryce type I and the pathogenesis of intralobar sequestration were discussed.
Adult↗
[Familial occurrence of intracerebral cavernous angioma: report of cases in brothers].
Familial occurrence of intracerebral cavernous angioma has been rarely reported. We report two histologically verified cases of cavernous angioma among brothers and review relevant cases in the literature. Case 1 is that of a 3-year-old boy who suffered front acute onset of headache, vomiting, and tonic-clonic type seizure. CT revealed a well-demarcated tumor with partial hemorrhage in the left frontal lobe which was strongly enhanced with contrast Medium. Complete excision was carried out and the patient had a satisfactory clinical course and was able to be followed up for 13 years after the Surgery. Case 2 is that of a 17-year-old boy who was the elder brother of case 1 and presented with gradually increasing episodes of a psychomotor seizure which started at the age of 16. CT and MRI revealed a well-demarcated tumor in the left subcortical temporal lobe and an asymptomatic small calcified lesion in the left subcortical parietal lobe. The temporal tumor was totally excised and histologically diagnosed as cavernous angioma. The seizures gradually decreased and eventually disappeared one year after the surgery. This report reviews 13 previously reported cases, and surgical indication for asymptomatic cases.
Adolescent↗
A novel isoform of the neurofibromatosis type-1 mRNA and a switch of isoforms during murine cell differentiation and proliferation.
Four types of cDNAs encoding the GTPase-activating protein-related domain (GRD) of the mouse neurofibromatosis type-1 gene (NF1) have been cloned. One of these isoforms was a newly identified form termed type IV. Analysis of the genomic structure of the mouse NF1-GRD revealed two exons (23A and 23B) between exons 23 and 24, leading to the production of four types of NF1-GRD cDNAs by an alternative splicing mechanism. Amino-acid sequences encoded by NF1-GRD are highly conserved between human and mouse. Analysis of the expression of these transcripts in various tissues of adult mouse revealed that the type-I transcript is predominantly expressed in neural tissues such as brain and spinal cord. Other forms, termed types II, III and IV, are also expressed in various tissues. The type-I and type-II transcripts are expressed equivalently in undifferentiated P19 mouse teratocarcinoma cells, whereas type-I expression becomes predominant during neuronal differentiation by retinoic acid treatment. Expression of type I is also shown to be correlated with cessation of cell proliferation in P19 cells, but not in NIH3T3 cells. These, together with other results, suggest that the four types of NF1-GRD transcripts generated by alternative splicing have some important biological roles in cell differentiation and proliferation.
Alternative Splicing↗
bcl-2 expression in epidermal keratinocytic diseases.
BACKGROUND: The bcl-2 protein has been shown to suppress apoptosis, and overexpression of the bcl-2 protein has been reported in several malignant tumors. Skin is one of the largest organs in the body, and the most common human malignancies arise from keratinocytes in the epidermis. In this paper, the authors analyzed immunohistochemically the expression of the bcl-2 protein in several keratinocytic (KC) tumors and inflammatory skin disorders to investigate the role of bcl-2 in the development of benign and malignant skin tumors. METHODS: Seventy-two frozen tissues from patients with inflammatory KC proliferation (chronic dermatitis [CD] and psoriasis vulgaris [PV]), seborrheic keratosis (SK), carcinoma in situ of KC tumors (actinic keratosis [AK] and Bowen's disease [BD]), basal cell carcinoma (BCC), and squamous cell carcinoma (SCC), 2 SCC cell lines, and 20 normal skin were immunostained with an anti-bcl-2 monoclonal antibody. RESULTS: Tissue with normal KC, CD, PV, and SK scarcely expressed the bcl-2 protein. Seventy-three percent of tissue with BD, 25% with AK, 67% with BCC, and 100% with SCC showed obvious bcl-2 protein expression. bcl-2 expression of BCC, BD, and SCC was restricted to the involved lesions, and surrounding normal tissue with KCs were bcl-2 negative. Interestingly, tissue with atrophic AK expressed no bcl-2 protein (none of five cases), whereas tissue with hypertrophic AK reacted weakly with the anti-bcl-2 antibody (two of three cases). CONCLUSIONS: bcl-2 protein expression in patients with KC may be related to tumorigenic proliferation possibly due to enhanced cell survival, but not when inflammatory proliferation of keratinocytes is present.
Bowen's Disease↗
Group II phospholipase A2 in invasive gastric cancer cell line is induced by interleukin 6.
To investigate the role of group II phospholipase A2(PLA2) in cancer, we examined the expression and secretion of group II PLA2 in response to the stimulation of interleukin 6(IL-6) in human gastric cancer cells in vitro. Group II PLA2 determined by a specific radioimmunoassay was constitutively produced in culture supernatant of KATO III (signet ring cell carcinoma) and MKN28 (well differentiated adenocarcinoma). This production in KATO III significantly increased with a treatment of IL-6, whereas that in MKN28 remained at a same level. Moreover, the quantitation by reverse transcription-polymerase chain reaction(RT-PCR) demonstrated the IL-6 inducible overexpression of group II PLA2 mRNA in KATO III. This transcription was mediated by NF-IL6, the same as in hepatocytes. These results suggest two possible mechanisms of group II PLA2 production by cancer cells in vivo, that is, cytokine-induced production and constitutive production.
Adenocarcinoma↗
Chronic active hepatitis in transgenic mice expressing interferon-gamma in the liver.
Interferon-gamma may play an important role in the immune response and in inflammatory diseases, including chronic active hepatitis. To understand the role of interferon-gamma in the regulation of inflammation and to establish a mouse model of chronic active hepatitis, we produced transgenic mice in which the mouse interferon-gamma gene was regulated by a liver-specific promoter, the serum amyloid P component gene promoter. Four transgenic mouse lines were generated, and two of these lines expressed mRNA of interferon-gamma in the liver. Levels of serum transaminases increased gradually as a function of age and were significantly higher than those of interferon-gamma-negative littermates after 4 weeks after birth. One transgenic mouse line showed a histology of chronic active hepatitis similar to that found in human patients, although cirrhotic changes such as fibrosis were scarce. Thus, the liver-specific production of interferon-gamma is sufficient to induce chronic inflammatory disease and this mouse is a transgenic model of chronic active hepatitis.
Alanine Transaminase↗
Determination of tissue specificity of the enhancer by combinatorial operation of tissue-enriched transcription factors. Both HNF-4 and C/EBP beta are required for liver-specific activity of the ornithine transcarbamylase enhancer.
The enhancer of the rat ornithine transcarbamylase gene is located 11 kilobases upstream from the transcription start site and has been shown to be hepatoma cell-specific. Using transgenic mice, we showed that this enhancer is capable of activating transcription in a liver-specific manner, inverting the tissue specificity of the homologous promoter that is by itself more active in the small intestine than in the liver. Transient transfection analysis with cultured hepatoma cells indicated that the enhancer activity resides in the approximately 110-base pair region containing four protein-binding sites, two for hepatocyte nuclear factor-4 (HNF-4) and two for CCAAT/enhancer binding protein (C/EBP), both of which are liver-selective transcription factors. Concatemerization of a region containing one HNF-4 and one C/EBP site led to reconstitution of the hepatoma cell-specific enhancer, and intactness of these two sites was strictly required for the enhancer activity. Furthermore, cotransfection experiments showed that both HNF-4 and C/EBP beta are necessary, and neither alone sufficient, for activation of the reconstituted enhancer in nonhepatic cells. Requirement of combinatorial operation of at least two liver-enriched transcription factors for transcriptional activation successfully explains why these liver-selective but not strictly liver-specific factors can confer more restricted liver specificity on transcription of their target genes.
Animals↗
Enhancement of tumor growth by basement membrane: modulation of growth and angiogenesis by laminin-derived synthetic peptides.
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Amino Acid Sequence↗
The effects of atrial natriuretic peptide on brain edema, intracranial pressure and cerebral energy metabolism in rat congenital hydrocephalus.
Atrial natriuretic peptide (ANP) regulates fluid and electrolyte homeostasis in the central nervous system. In this study, we evaluated the effects of ANP on brain edema, intracranial pressure (ICP) and cerebral energy metabolism in congenital hydrocephalus in rats. Brain edema, indicated by the longitudinal relaxation time (T1), was evaluated by 1H-magnetic resonance imaging (MRI). The ICP was monitored with a miniature pressure-transducer with telemetric system. Cerebral energy metabolism, indicated by PCr/Pi ratio, was measured by 31P-magnetic resonance spectroscopy (MRS). The rats were given 10 microliters of ANP in the left cerebral ventricle. Three different concentrations of ANP were given; 0.2 (group I), 2.0 (group II) and 20.0 (group III) micrograms/10 microliters, respectively. 10 microliters of saline was injected into the ventricle of the control group rats. There were no significant changes of ICP, T1 value and PCr/Pi ratio among the control group, group I and group II. In group III, in contrast, ICP decreased significantly at 20 minutes after ANP administration and stayed at this ICP level for 60 minutes. The T1 value decreased and PCr/Pi ratio increased 30 minutes after ANP administration. This study revealed that intraventricularly administered ANP could decrease ICP, reduce brain edema and improve the cerebral energy metabolism in rats with congenital hydrocephalus.
Animals↗
The effect of 6 kHz tone exposure on inner ear function of the guinea pig: relation to changes in cochlear microphonics, action potential, endocochlear potential and chemical potentials of K(+)-ions and Na(+)-ions, using a double-barrel glass electrode.
Using 97 male albino guinea pigs and applying electrophysiological methods, the effects of a 6 kHz tone were investigated at a moderate sound pressure level to the inner ear during a 24-h exposure time. Following exposure to the 6 kHz tone at 90 dB, cochleas showed decreased maximum output voltage of cochlear microphonics (CM) and action potential (AP). In the endolymph, K+ ion and Na+ ion concentrations remained unchanged during 40 min anoxia and 90 dB tone exposure. At 80 dB sound exposure decreases in maximum output voltage of CM and AP and decreases in the absolute value of EP could not be detected. Endolymph K(+)-ion Na(+)-ion concentrations were also unchanged. These findings indicate that diffusion potentials are induced at the same time as decreases of maximum output voltage in CM induced by exposure to sound at 90 dB.
Action Potentials↗
Normalization of hair growth in sparse fur-abnormal skin and hair (SPF-ASH) mice by introduction of the rat ornithine transcarbamylase (OTC) gene.
The sparse fur-abnormal skin and hair (SPF-ASH) mouse is a model for the human X-linked hereditary disease, ornithine transcarbamylase (OTC) deficiency. This condition is characterized by abnormal skin and delayed hair growth, hyperammonemia, orotic aciduria and low levels of serum citrulline and arginine. Murakami et al. [1] established a line of transgenic mice, by introducing the recombinant rat OTC (rOTC) gene into fertilized C57BL mouse eggs. We introduced the rOTC gene into SPF-ASH mice by mating SPF-ASH heterozygotes and transgenic mice, which carried this gene. The hemizygous SPF-ASH mice bearing the rOTC gene showed normal hair growth without sparse fur, normal urinary orotic acid excretion and normal serum citrulline and arginine levels. These mice showed OTC activities 2 and 6 times higher in the liver and small intestine, respectively, than the SPF-ASH mice but about 12% and 27% those of the controls [2].
Animals↗
The murine interleukin-5 receptor alpha-subunit gene: characterization of the gene structure and chromosome mapping.
To understand better the regulation of interleukin-5 receptor alpha-subunit (IL-5R alpha) expression, we have isolated the genomic clones of mouse IL-5R alpha (mIL-5R alpha) and analyzed the structure of the gene. The gene spans more than 35 kb and is composed of 11 exons. We found that two mRNAs encoding secreted forms of mIL-5R alpha result from differential splicing events. We identified the transcriptional start site by primer extension analysis of mIL-5R alpha mRNA. Nucleotide sequence of the 5'-flanking region contains potential binding sites for transcription factor Ap1, AP-1, GATA-1, and PU.1. About 260 bp sequence of the 5'-flanking region exhibited promoter activity when it was linked to a promoterless bacterial chloramphenicol acetyltransferase (CAT) gene. The promoter activity was seen not only in the IL-5-dependent pre-B-cell line Y16, but also in fibroblast cell line NIH-3T3. Comparison of the exon-intron boundaries of mIL-5R alpha genes with those of other members of the cytokine receptor family reveals a conserved evolutionary structure. By fluorescence in situ hybridization analysis, the mIL-5R alpha gene has been assigned to chromosome 6.
Animals↗
Effect of preservatives on systemic delivery of insulin by ocular instillation in rabbits.
The effects of absorption promoters and ophthalmic preservatives on the systemic absorption of insulin through the ocular route were investigated in albino rabbits. Insulin absorption was evaluated by its hypoglycaemic response. Although ocular instillation of insulin alone did not decrease the serum glucose concentration, instillation of insulin with absorption promoters such as EDTA and saponin decreased it. The promoting effect depended on the concentration of the absorption promoters. Of ophthalmic preservatives investigated (benzalkonium chloride, paraben, 2-phenylethanol, benzyl alcohol and sorbic acid), benzalkonium, chloride and paraben showed promoting effects. The promoting effect for benzalkonium chloride was reversible and dependent on concentration of both benzalkonium chloride and insulin in the formulation.
Absorption↗
Anticancer effects of adriamycin-loaded hydroxyapatite implants determined in a Swarm rat chondrosarcoma model.
We investigated the antitumor effects of adriamycin (ADR)-loaded hydroxyapatite (HAP) beads in a Swarm rat chondrosarcoma model. When one ADR-loaded HAP bead (ADR: 0.8 mg/bead) was implanted into the central portion of a rat bearing tumor, the ADR-loaded HAP beads showed good therapeutic effects, increasing the life span (ILS) by 90%. Significantly, leukopenia and diarrhea were not observed. These results suggest that HAP delivery offers an interesting and a potentially effective method.
Animals↗
Antitumor effects and distribution of adriamycin incorporated into hydroxyapatite implants in a cancer rat model bearing swarm rat chondrosarcoma.
We investigated the antitumor effects and tissue distribution of adriamycin (ADR) incorporated into a hydroxyapatite (HAP) bead in a cancer rat model bearing Swarm rat chondrosarcoma. The Porous HAP bead (8.48 mm in diameter, 531 +/- 0.7 mg in weight) was used as a model bone graft. One ADR-HAP bead (ADR 0.4 mg-6.0 mg/bead) was implanted s.c. into a Sprague-Dawley rat at 6 days postinoculation of Swarm rat chondrosarcoma. ADR-HAP beads showed strong antitumor activities in a dose dependent manner. The dose of 6.0 mg/bead showed the highest efficacy with no toxic death: It caused a 98% growth inhibition on Day 31 postinoculation and a survival advantage of a 339% increase in life span. After the implantation of the ADR-HAP bead (0.4 mg/bead/body) and the i.v. administration of an equal dose of free adriamycin, we determined the tissue distribution of ADR for up to 90 days. ADR-HAP bead implanted in the tumors released ADR over a 12-week period in the target area. The diffusion of the drug to other organs such as the heart and liver was very low compared with the tumors. The area under the ADR concentration-time curve (AUC) of the tumors was 181.6 micrograms.day/g and 5.22 micrograms.day/g after the implantation of the ADR-HAP bead and the i.v. administration of free ADR, respectively. The targeting index of the tumors, defined as the ratio of the AUC after the implantation of the ADR-HAP bead to that after administration of free ADR, was 34.8.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
Resistance to cyclophosphamide-induced diabetes in transgenic NOD mice expressing I-Ak.
Transgenic expression of the MHC (major histocompatibility complex) class II I-Ak molecule was previously shown to effectively reduce the incidence of insulitis in non-obese diabetic (NOD) mice at the age of 20 weeks. We have further characterized the expression and function of the I-Ak molecule and examined its effects on the incidence of diabetes in NOD mice. The newly expressed I-Ak molecule was recognized as an alloantigen by the T lymphocytes of normal NOD mice as shown by mixed lymphocyte reaction (MLR). The levels of endogenous I-Ag7 expression on peripheral blood lymphocytes were not affected by the transgene expression. Transgenic NOD mice were completely resistant to spontaneous diabetes, but the treatment by cyclophosphamide, which effectively induces diabetes in normal NOD mice, caused diabetes, although at a much lower incidence than that of normal NOD mice. On the basis of these findings, we discuss the role of I-Ak in the prevention of diabetes in NOD mice.
Animals↗
Use of the hemagglutinating virus of Japan (HVJ)-liposome method for analysis of infiltrating lymphocytes induced by hepatitis B virus gene expression in liver tissue.
We previously developed a method for introducing foreign genes into liver tissue using liposomes with incorporated hemagglutinating virus of Japan (HVJ, Sendai virus), and found that liver cells transfected with the E. coli beta-galactosidase gene or the gene for hepatitis B virus (HBV) surface protein (HBsAg) expressed these proteins in vivo. Here, we analyzed cellular reactions leading to hepatitis in the liver by expressing the genes of HBV in vivo. Lymphocytes were eluted directly from liver transfected with the HBsAg genes and shown to be cytotoxic only to cells expressing HBsAg in vitro. These lymphocytes were identified as cytotoxic T lymphocytes with the CD4- CD8+ phenotype. Transfer of these lymphocytes to transgenic mice with the whole HBV genome led to elevation of the serum glutamic-pyruvic transaminase (SGPT) level, indicating the induction of hepatitis due to the cytotoxic T lymphocytes in vivo. Similarly, direct transfer of the gene for the HBV secretory core protein (HBeAg) induced expression of HBeAg in hepatocytes and the appearance of antibody against HBeAg in the serum. However, using this system, we found that the lymphocytes infiltrating the transfected liver showed no cytotoxicity specific for HBeAg. These results indicate that expression of HBsAg, one of the components of virions, in animal liver induced hepatitis efficiently through generation of specific cytotoxic T lymphocytes (CTL) without any expression of the other viral components. This in vivo experimental system should be useful for evaluating how expression of a given gene induces cellular reactions and intrinsic functions in the living body.
Animals↗