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N Shimizu

Publications and source records attributed to N Shimizu.

At least 127 records · Page 7Linked to original sources
PubMed2001

[The role of Helicobacter pylori infection and effect of eradication in experimental animal models of gastric carcinogenesis].

Helicobacter pylori (Hp) was concluded to be 'a definite carcinogen' by WHO/IARC in 1994. We have demonstrated that Hp infection enhances chemical carcinogen-induced stomach carcinogenesis in Mongolian gerbils (MGs) using N-methyl-N'-nitro-N-nitrosoguanidine or N-methyl-N-nitrosourea. Not only well-differentiated but also poorly differentiated and signet ring cell types of cancers are observed, mimicking the human case. Eradication of Hp was found to be effective of preventing enhancing effects. Hp infection alone, without chemical carcinogens, caused submucosal proliferating lesions, but not gastric carcinomas, in contrast to reports that Hp infection alone may act on a complete carcinogen. Precise pathological assessment is required to solve this controversy. Here we demonstrate alleviation of Hp induced gastric lesions with eradication in MGs.

Animals↗
PubMed2001

[Two cases of advanced and metastatic breast cancers treated by docetaxel in combination with intra-arterial infusion of adriamycin].

Two cases of advanced and metastatic breast cancers were treated by docetaxel (TXT) in combination with intra-arterial infusion of adriamycin (ADM). Patients received 60 mg/body TXT i.v. and 30 mg/body ADM ia (AT therapy) bi-weekly. Clinical responses were observed in these two patients and the durations of responses were over 20 weeks. Critical toxicities of grade 2 leukopenia and alopecia were observed but grade 4 severe toxicities were not. Thus AT therapy can be easily and safely performed with outpatients. This therapy can improve the response rate and time to progression; therefore phase I or phase I/II clinical trials of AT therapy in Japan are recommended.

Adult↗
PubMed2001

Evolutionary dynamics of the human immunoglobulin kappa locus and the germline repertoire of the Vkappa genes.

We have determined the entire nucleotide sequence of the human immunoglobulin kappa locus, comprising a total of 1,010,706 nucleotides. The 76 Vkappa genes found by a hybridization-based approach and their classification in 7 families were confirmed. A Vkappa orphon located near the locus was also sequenced. In addition, we identified 55 novel Vkappa relics and truncated pseudogenes, which establish 5 new families. Among these 132 Vkappa genes, 46 have open reading frames. According to the databases and the literature, 32 unique Vkappa genes and 5 identical gene pairs form VJ-joints, 27 unique genes and 4 gene pairs are transcribed, and 25 unique genes and 4 gene pairs produce functional proteins. The Vkappa gene locus contains a 360-kb inverted duplication, which harbors 118 Vkappa genes. A comparison of the duplicated Vkappa genes suggests positive selection on the complementarity-determining regions of the duplicated genes by point mutations. The entire duplication unit was divided into 13 blocks, each of which has its distinct nucleotide sequence identity to its duplication counterpart (98.1 - 99.9 %). An inversion-mediated mechanism is suggested to generate the high-homology blocks. Based on the homology blocks and the mutation rates, the inverted duplication is assumed to have taken place approximately 5 million years ago. An orphon Vkappa gene near the kappa locus and a cluster of five Vkappa orphons on chromosome 22 have no counterparts within the kappa locus. This suggests possible mechanisms of the transposition of orphon Vkappa genes.

Base Composition↗
PubMed2001

[Current status and future of lung transplantation].

Lung transplantation has been performed successfully since 1983 in patients with various end-stage lung diseases including primary pulmonary hypertension. More than 10,000 lung transplants have been reported in The Registry of the International Society for Heart and Lung Transplantation. In contrast, a transplant law became effective in Japan only recently and 11 lung transplants have been performed with excellent results. We performed the first successful living-donor lobar lung transplantation for a 19-y-o-f with primary pulmonary hypertension on January 5, 2001 using her father's right lower lobe and her mother's left lower lobe. When the patients with primary pulmonary hypertension do not respond to prostacyclin therapy, lung transplantation is a workable option.

Adult↗
PubMed2001

Polymorphisms of two fucosyltransferase genes (Lewis and Secretor genes) involving type I Lewis antigens are associated with the presence of anti-Helicobacter pylori IgG antibody.

Helicobacter pylori attach to the gastric mucosa with adhesin, which binds to Lewis b (Le(b)) or H type I carbohydrate structures. The Secretor (Se) gene and Lewis (Le) gene are involved in type I Le antigen synthesis. The present study was performed to investigate the possibility that Se and Le gene polymorphisms alter the risk of H. pylori infection. Two hundred thirty-nine participants were genotyped for Se and Le and tested for the presence of anti-H. pylori IgG antibodies. Using the normal gastric mucosa from 60 gastric cancer patients, we assessed immunohistochemically whether type I Le antigen expression depended on the Se and Le genotypes. The H. pylori infection rate was positively associated with the number of Se alleles (se/se group, 45.1%; Se/se group, 64.6%; and Se/Se group, 73.3%) and negatively associated with the number of Le alleles (le/le group, 76.4%; Le/le group, 68.3%; and Le/Le group, 55.6%). When the subjects were classified into three groups [low risk, (se/se, Le/Le) genotype; high risk, (Se/Se, le/le), (Se/Se, Le/le), and (Se/se, le/le) genotypes; moderate risk, other than low- or high-risk group], the odds ratio relative to the low-risk group was 3.30 (95% confidence interval, 1.40-7.78) for the moderate-risk group and 10.33 (95% confidence interval, 3.16-33.8) for the high-risk group. Immunohistochemical analysis supported the finding that Se and Le genotypes affected the expression of H. pylori adhesin ligands. We conclude that Se and Le genotypes affect susceptibility to H. pylori infection.

Adult↗
PubMed2001

Familial Parkinson's disease. Alpha-synuclein and parkin.

We have reviewed recent progress in establishing the function of alpha-synuclein and parkin in relation to nigral degeneration in autosomal dominant and autosomal recessive PD. Mutations of alpha-synuclein (Ala53Thr and Ala30Pro) cause a form of autosomal dominant PD with early onset. Parkin is a novel protein expressed in the cytoplasm, including the terminal regions and Golgi apparatus. Mutations of parkin cause a form of autosomal recessive young-onset PD (ARJP). Both proteins appear to be associated with fast axonal transport. In addition, in sporadic PD, normal alpha-synuclein shows an increased tendency to self-aggregate. Thus, altered axonal transport of presynaptic proteins appears to play a crucial role in neurodegeneration in PD.

Humans↗
PubMed2001

Aggregation pheromone activity of the female sex pheromone, beta-acaridial, in Caloglyphus polyphyllae (Acari: Acaridae).

Caloglyphus (= Sancasania) polyphyllae discharges from a pair of opisthonotal glands a characteristic set of volatiles, i.e. three monoterpenes and seven hydrocarbons. Among them, beta-acaridial, which is known as the female sex pheromone of the species and has antifungal activity, was newly identified as the aggregation pheromone for unfeeding and unmating mites. Feeding mites, however, exhibited sexually aroused behavior instead of the tendency to cluster when exposed to beta-acaridial. This is the first example of the compound demonstrating two pheromone functions depending upon the circumstances faced by the mites.

Acari↗
PubMed2001

[Wilson disease].

Explore the source record for details and available documents.

Adolescent↗
PubMed2001

Abnormalities of gonadotrophs in the adenohypophysis of infertile male PD rats.

Male PD strain rats are sterile in the homozygous condition (pd/pd) due to abnormal spermatogenesis detectable at around nine weeks of age. Previous studies have indicated electron microscopic abnormalities in the Sertoli cells of pd/pd males at three and 12 weeks of age. Since spermatogenesis and Sertoli cell function depend on gonadotropins (luteinizing and follicle-stimulating hormones [LH and FSH]) and testosterone, production and/or secretion of these hormones might be altered in pd/pd males. The aim of the study reported here was to investigate the hormonal status of pd/pd males at three, six, and nine weeks of age. Although alteration was not evident in the LH-immunoreactive cells, FSH-immunoreactive cells in pd/pd males were small in size with scant cytoplasm and were reduced in number and area (73 and 51% of phenotypically normal pd/+ males, respectively) at three weeks of age, although serum FSH concentration was similar to that in pd/+ males. At six and nine weeks of age, percentages of the areas occupied by LH- and FSH-immunoreactive cells in pd/pd males were higher than those in pd/+ males. Serum FSH concentration in pd/pd males was significantly high at nine weeks of age, although a difference in serum LH and testosterone concentration was not evident. These results suggest that FSH production in pd/pd males is decreased at three weeks of age. This might be associated with the Sertoli cell abnormalities and subsequent abnormal spermatogenesis seen in adult life.

Animals↗
PubMed2000

How can human and simian immunodeficiency viruses utilize chemokine receptors as their coreceptors?

Several chemokine receptors (CKRs) act as coreceptors of human immunodeficiency virus type 1 (HIV-1), type 2 (HIV-2) and simian immunodeficiency virus (SIV). These CKRs interact with the V3 domain of the envelope (env) protein of HIV/SIV. In this study, we found that the amino acid sequences of two chemokines (SDF-1beta and RANTES), whose receptors (CXCR4 and CCR5) act as major coreceptors for HIV-1, HIV-2 or SIV, showed statistically significant similarity to those of the region containing the third variable (V3) and the third conserved (C3) domains (the V3--C3 domain) of the env protein of HIV-1 and HIV-2. We made a multiple alignment of amino acid sequences for 24 chemokines and the region encompassing the second conserved (C2), V3 and C3 domains (the C2--V3--C3 region) of 10 strains of HIV/SIV. Surprisingly, the hydropathic profile and several important amino acids for protein conformation, such as cysteine and tryptophan, are remarkably conserved between chemokines and the V3--C3 region of HIV/SIV. Moreover, hydrophobic amino acids, such as leucine, isoleucine and valine, are found to be clustered both in the amino-terminal region of chemokines and the C2 domain of HIV/SIV. Thus, chemokines have significantly similar profiles of amino acid properties to those of the C2--V3--C3 region of the env protein of HIV/SIV. These findings raise a hypothesis that chemokines and the C2--V3--C3 region have a common origin. Namely, the HIV/SIV ancestor incorporated a chemokine gene into its env gene. The captured chemokine gene has rapidly diverged by frequent mutations specific to the retroviral genome, and thereby obtained the ability to interact with various CKRs in a short period of time. This paper proposes that the capture of a ligand gene of the host cells into the viral genome may be one of the important mechanisms of viral evolution to expand its host range and generate new viral species.

Amino Acid Sequence↗
PubMed2000

The 5-HT(1A) receptor agonist, 8-OH-DPAT, attenuates stress-induced anorexia in conjunction with the suppression of hypothalamic serotonin release in rats.

The effect of the selective 5-HT(1A) receptor agonist 8-hydroxy-2-(di-n-propylamino) tetralin (8-OH-DPAT) on stress-induced anorexia and serotonin (5-HT) release in the rat hypothalamus was studied with brain microdialysis. Subcutaneous injection of 8-OH-DPAT (1 mg/kg) significantly attenuated the immobilization-induced anorexia for 3 h, but had no effect during the following 9 h. Injection of 8-OH-DPAT itself had no effect on basal release of 5-HT, while it significantly blocked the immobilization-induced 5-HT release in the lateral hypothalamus. The results suggest that 8-OH-DPAT attenuated the stress-induced anorexia through the activation of 5-HT(1A) autoreceptors in dorsal raphe nucleus.

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMed2000

Sequence analysis and expression of the P450 aromatase and estrogen receptor genes in the Xenopus ovary.

Recent studies point to a key role for the estrogen synthesizing enzyme P450 aromatase (P450 arom) in ovary determination in fish, birds and reptiles. It is unclear whether estrogen synthesis is important in sex determination of Xenopus gonad. To determine whether the aromatase gene is transcribed in the gonads of Xenopus tadpoles during the sex determination, we cloned a P450 arom cDNA and examined the level of P450 arom and estrogen receptor (ER) gene expression in association with estrogen activity. cDNA clones for P450 arom were isolated from a Xenopus ovarian cDNA library. There was an open reading frame (ORF) of 1500 bp from the ATG start to TAA stop codons encoding 500 predicted amino acids. cDNAs for P450 arom have previously been cloned from various vertebrates. The homology between the Xenopus P450 aromatase and the human P450 arom was higher. The expression of the P450 arom gene was mainly limited to reproductive organs. To determine the beginning of estrogen activity in gonads of embryos, expression of the aromatase and ER gene was also examined by RQ-RT-PCR. Both Xenopus aromatase and ER mRNA was detected at stage 51 in gonads. These observations are consistent with estrogens having a key role in ovarian development in various other vertebrates.

Amino Acid Sequence↗