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H Kiyosawa

Publications and source records attributed to H Kiyosawa.

18 recordsLinked to original sources
PubMed1995

The replication origin position and its relationship to a negative trans-acting transcription regulator encoded by Dictyostelium discoideum nuclear plasmid Ddp1.

The replication origin of the Dictyostelium discoideum plasmid Ddp1 was localized to a 543-bp region. This includes most of the AT-rich intergenic region between the G1 and G5/D6 genes containing both of their promoters and multiple copies of a TTTTGACT repeat. The G5/D6 gene, which lies adjacent to, and partially overlaps, the 543-bp origin region, encodes a trans-acting factor that negatively regulates transcription of the G4/D5 gene. Inactivation of the G5/D6 gene led to expression of a transcript (G6) 0.2 kb larger than the D5 transcript from the G4/D5 gene in vegetative and developing cells. The G5/D6 gene also regulates transcription of the G1, G2/G3/D4 and G5/D6 genes either alone or in concert with other Ddp1 gene products.

Animals↗
PubMed1994

Compatible Dictyostelium mucoroides nuclear plasmids Dmp1 and Dmp2 both belong to the Ddp1 plasmid family.

Dictyostelium mucoroides plasmids Dmp1 and Dmp2 are naturally occurring compatible members of the Dictyostelium Ddp1 plasmid family found in the same wild isolate strain. The nucleotide sequences of Dmp1 (5983 bp) and Dmp2 (6018 bp) are 74% identical and each carries open reading frames (ORFs) similar to the G1 and G5 ORFs of the Dictyostelium discoideum plasmid Ddp1. The predicted protein product of the Ddp1 G1 ORF is 49% similar to that of the Dmp1 G1-like ORF and 52% similar to that of the Dmp2 G1-like ORF. For the G5 and G5-like ORFs the corresponding values are 47 and 43%, respectively. The G1 and G5 ORFs of Ddp1 are transcribed during both vegetative growth and development of the asexual fruiting body. The G1-like ORF of Dmp2 is expressed in vegetative and developing cells, while that of Dmp1 appears to be expressed mostly in developing cells. The G5-like ORFs of Dmp1 and Dmp2 are expressed in both vegetative and developing cells. Dmp1 and Dmp2 differ from Ddp1 in (1) lacking homologs for the Ddp1 G2/G3/D4, G4/D5, D1/D3, and D2 ORFs; (2) containing multiple copies of a 173 bp direct repeat; and (3) having a different orientation of the G1 ORF relative to the G5 ORF. These findings suggest that the basic replicon unit of the Ddp1 plasmid family is composed of an origin of replication coupled to G1-like and G5-like genes. The additional ORFs and direct repeat elements in Ddp1, Dmp1, and Dmp2 may provide accessory functions beneficial to plasmid maintenance. Shuttle vectors based on Dmp1 or Dmp2 replicate in D. discoideum transformants.

Amino Acid Sequence↗
PubMed1994

Nucleotide sequence of Ddp1, a high copy number nuclear plasmid of Dictyostelium discoideum.

The complete nucleotide sequence of Ddp1, a high copy number 13.7-kbp endogenous nuclear plasmid of Dictyostelium discoideum is presented. Previous studies have shown nine transcripts which map to five different regions of Ddp1, suggesting alternative transcription initiation sites and/or post-transcriptional processing. The sequence presented here shows five long open reading frames corresponding to previously known transcribed regions, as well as an additional reading frame, in the region of the presumed origin of replication. Two of the predicted proteins from the Ddp1 reading frames have potential leader sequences and transmembrane domains, while the rest, if translated, would encode soluble proteins. One of these has both leucine zipper and zinc finger-like motifs. Sequences upstream of the reading frames show strong similarities to chromosomal promoter elements, suggesting that transcription of at least some of the plasmid-encoded genes is regulated by factors which regulate chromosomal transcription in this organism. The region containing the presumptive origin of replication contains the promoters of the major growth-specific gene, as well as a second gene; thus, the processes of transcription and replication of Ddp1 may be intimately linked. The origin-encompassing region has a long homopurine/homopyrimidine stretch, which is similar to sequences shown in vitro to be capable of forming a triple helix structure through Hoogsteen base pairing. Possible roles for these sequences and the products of the ORFs in plasmid maintenance are discussed.

Animals↗
PubMed1994

Plasmid maintenance functions encoded on Dictyostelium discoideum nuclear plasmid Ddp1.

All of the plasmid-carried genes expressed during vegetative growth are essential for long-term maintenance of plasmid Ddp1 in the nucleus of Dictyostelium discoideum. Deletion of Ddp1 genes expressed only during development had no detectable effect on plasmid maintenance. Deletion of vegetatively expressed genes, either singly or in pairs, resulted in (i) a rapid loss of plasmid from cells grown in the absence of selection for plasmid retention, (ii) variation in the proportion of monomer to multimer forms of the plasmid molecules, and/or (iii) abnormalities in plasmid copy number. At least two plasmid-encoded gene products influence patterns of expression of plasmid genes.

Animals↗
PubMed1993

Small circular plasmids of the eukaryote Dictyostelium purpureum define two novel plasmid families.

Two novel groups of circular, nuclear plasmids were discovered in the simple eukaryote Dictyostelium purpureum. They define two new Dictyostelium plasmid families each containing three members: Dpp1A, Dpp1B, and Dpp2 in the Dpp1 family, and Dpp3, Dpp4, and Dpp5 in the Dpp3 family. These plasmids are among the smallest known, ranging in size from 1309 bp (Dpp1A and Dpp1B) to 1961 bp (Dpp4). Family members are very similar. The most distantly related members of the Dpp1 family (Dpp1A and Dpp2) are 89% identical, while the most distantly related members of the Dpp3 family (Dpp3 and Dpp4) are 91% identical. No sequence similarity is found between these plasmid families, or to any other known plasmid or chromosomal DNA sequence. A 72-bp inverted repeat present in one copy in Dpp1A and Dpp1B is tandemly repeated in Dpp2. The Dpp3 family contains a region of 102-160 nucleotides rich in short, overlapping direct sequence repeats. This region is present once in Dpp3 and Dpp5 and is tandemly repeated in Dpp4. The repeat structures in the Dpp1 and Dpp3 families are relatively rich in GC base pairs (29-41%) in comparison to the unique sequence regions of the plasmids (16-22%). The longest open reading frame (ORF) beginning with an AUG codon in these plasmids is 168 bp in the Dpp3 family, although longer ORFs without AUG start codons (up to 201 bp) also exist. Northern blot analysis did not detect any plasmid-specific transcripts in total RNA prepared from vegetative cells carrying Dpp1A or Dpp3.

Animals↗
PubMed1993

Circadian variations of acute toxicity and blood and brain concentrations of inhaled toluene in rats.

To investigate circadian variations in the acute toxicity of toluene, rats were exposed to it (2000 ppm or 4000 ppm) both in the dark (the animals' active phase) and the light (the inactive phase) for 4 hours. The performance decrements of rats were greater in the light phase than in the dark phase in all time zones of exposure to toluene. In the dark phase, the performance recovered almost to that pre-exposure, whereas a significant delay of recovery was noted in the light phase. The differences in the number of lever presses between exposure to 2000 ppm toluene and control (air) exposure were also greater in the light phase than in the dark phase. Significant differences according to the time of exposure were also found in toluene concentrations in blood and the brain. Both blood and brain concentrations in the light phase were higher than those in the dark phase at four hours after exposure to 2000 ppm toluene or at two hours after exposure to 4000 ppm toluene. These results suggest that there was a significant difference in circadian susceptibility after exposure to toluene, which might be caused by circadian differences in the pharmacokinetics of toluene in the light and dark phases.

Animals↗
PubMed1993

[Immunoglobulin decrease accompanying adverse reactions with bucillamine].

Forty-two RA patients treated with Bucillamine (B) were divided into two groups with (n = 26) and without (n = 16) adverse reactions, and IgG, M, A and total protein concentration x globulin ratio (Ig) before and after B were compared. IgG did not differ before B administration, but was significantly lower in the adverse reactions group after B, and in each group it was significantly lower after B treatment with a much greater decrease demonstrated in the adverse reactions group. IgA before B did not differ either between the two groups or between before and after B administration in the non-adverse reaction group, but was significantly lower only after B in the adverse reaction group. IgM did not differ either before or after B treatment between the two groups, and was significantly lower following B administration in both groups. Ig showed results similar to IgA. In the adverse reaction group, IgG, A, M and Ig recovered following suspension of administration. It is concluded that the adverse reaction brought on by B administration might occur with the decrease in immunoglobulin.

Agammaglobulinemia↗
PubMed1992

DNA strand cleavage at 8-hydroxyguanine residues by hot piperidine treatment.

The two findings indicate that 8-hydroxyguanine(8-OH-Gua) is a hot piperidine-sensitive lesion in DNA. These are cleavages of DNA containing 8-OH-Gua at the site of this residue and decomposition of 8-hydroxydeoxyguanosine when the DNA and nucleoside were treated in 1 M piperidine for 30 min at 90 degrees C. However, no cleavage was observed in DNA containing 8-hydroxyadenine or O6-methylguanine. 8-OH-Gua was found to be different from apurinic sites that are also alkali-labile lesions since the former was more resistant to alkali treatment. This property of 8-OH-Gua can be used as a check for the incorporation of this base into DNA after the synthesis of DNA containing 8-OH-Gua at a specific position or possibly can be one of the markers for the identification of 8-OH-Gua formed in DNA exposed to reactive oxygen species.

Base Sequence↗
PubMed1992

[A case of asymptomatic endobronchial lipoma followed for 4 years].

Bronchoscopy was performed on a 68-year-old male patient with pulmonary tuberculosis, and revealed a yellow smooth polypoid tumor in the lumen of the left upper division bronchus. The histopathological diagnosis of the biopsy specimen was endobronchial lipoma. Since the patient did not have any symptoms due to the lipoma, we performed treatment for tuberculosis and continued careful observation of the tumor. During the subsequent 4 years, the patient developed no complications such as obstructive pneumonia, and the size of the tumor under bronchoscopic observation did not change. Endobronchial lipoma is a very rare benign tumor. Almost all reported cases have undergone operation or endoscopic surgery. This case is the first that was followed over 4 years without surgical procedure. The findings of follow-up bronchoscopic examination suggest that the growth rate of endobronchial lipoma is very slow. Furthermore, we reviewed 36 cases of endobronchial lipoma in the Japanese literature, including our case. Smoking seems to have a strong relation to the occurrence of the tumor. It is noteworthy that 6 cases had separate malignancies, but the direct relationship between endobronchial lipoma and such malignancies is unclear.

Aged↗
PubMed1990

Cigarette smoking induces formation of 8-hydroxydeoxyguanosine, one of the oxidative DNA damages in human peripheral leukocytes.

Active oxygen species (AOS) such as O2- and H2O2 have been shown to be generated from both gas and tar phases of cigarette smoke and it has been suggested that they are involved in carcinogenesis due to cigarette smoking. Therefore, we investigated the effect of cigarette smoking on oxidative DNA damages in human peripheral blood cells using 8-hydroxydeoxy-guanosine (8-OH-dG) as a marker. From ten healthy male volunteers aged 20-22 years, 5 ml of blood was taken before and 10 minutes after smoking 2 cigarettes in 10 minutes. After lysis of blood cell membranes leukocyte DNA was isolated using a DNA extractor and 8-OH-dG levels were determined using high performance liquid chromatography (HPLC) with electrochemical detection. The mean levels of 8-OH-dG increased significantly (P less than 0.05) from 3.3 +/- 0.8/10(6) dG (mean +/- SD) to 5.1 +/- 2.5 after smoking. These results indicate that cigarette smoking induces oxidative DNA damage in peripheral blood cells in a relatively short time.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed1988

Decrease of serum triglyceride in normal rats fed with 2000 ppm aluminum diet for 67 days. I. Feeding young rats sucrose, lactose, milk, casein or soy-protein diets with addition of aluminum chloride.

Aluminum (Al) compounds are widely used in drugs and food additives but the toxicity of such compounds is not known in detail except in patients with renal insufficiency (J. W. Coburn and A. C. Alfrey, 1986, Kidney Int. 29, Suppl. 18). In this experiment, toxicity of ingested Al was investigated in relation to nutritional conditions in normal rats having no renal insufficiency. Sucrose, lactose, milk, casein and soy-protein diets were prepared. As the Al source, aluminum chloride (AlCl3) was added to these diets at the level of 2000 micrograms/g (ppm). Male weanling Wistar rats were fed for 67 days without any Al effect on body weight gain. After a half-day starvation they were terminated. The significance of difference resulting from Al treatment was statistically tested between rats consuming diet with or without added Al. Serum Al concentrations did not exceed 20 ng/ml in any of the groups. Tibia Al concentration doubled in rats consuming added Al in every diet but lactose. Liver Al concentration increased significantly in the Sucrose, Milk, and Casein groups compared to each Control group consuming diet without addition of Al. No lactose effect on Al accumulation was observed. With Al treatment, anemia and hypophosphatemia were not observed, but a decrease in tibia weight was observed with every diet. Aluminum-dependent decreases in serum triglyceride (TG) concentration were also observed in all dietary groups, without any effect on serum cholesterol or phospholipid (P-lipid) concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)

Aluminum↗
PubMed1988

Decrease of serum triglyceride in normal rat fed with 2000 ppm aluminum diet for 67 days. II. Feeding young and adult rats a sucrose diet with addition of aluminum hydroxide and aluminum potassium sulfate.

To confirm the hypotriglyceridemic effect of aluminum (Al), male weanling and adult Wistar rats were fed sucrose diets with the addition of aluminum hydroxide (Al(OH)3) or aluminum potassium sulfate (AlK(SO4)2) for 67 days. As in the foregoing report (C. Sugawara, N. Sugawara, H. Kiyosawa, and H. Miyake, Fundam. Appl. Toxicol. 10, 607-615), no Al-induced anemia or hypophosphatemia was observed and serum Al did not exceed 20 ng/ml. Serum triglyceride (TG) was decreased by aluminum. Serum TG was significantly correlated with the serum nonesterified fatty acid (NEFA) concentration in both the Young groups (R = 0.757, n = 22, p less than 0.01) and the Adult groups (R = 0.727, n = 19, p less than 0.01). Neither serum cholesterol nor phospholipids was affected by Al ingestion. Aluminum caused a decrease in hepatic glycogen in all groups, but the decrease was significant only in Adult groups. Glycerol tri[9,10(n)-3H]oleate was administered by gastric tube into rats fed for 81 days with experimental diets. In all the Al-treated groups serum 3H was significantly greater than in control groups at 3 hr after intubation. At 24 hr after intubation, serum 3H did not differ between Control and Al-treated groups. Total 3H at 24 hr found in serum, liver, and epididymal adipose tissue was not changed significantly by Al feeding. These effects were observed without measurable increase of Al in the serum.(ABSTRACT TRUNCATED AT 250 WORDS)

Alum Compounds↗
PubMed1987

[Dietary vitamin intake and cancer].

We collected information on dietary intake from 9230 participants aged 40 years old or more by means of self-administered food frequency questionnaire in Fujieda city in order to conduct prospective study to examine the relationship between dietary VA, C and carotene intakes and subsequent risk of cancer in August 1985. To estimate VA, C, and carotene intakes from this questionnaire we multiplied food frequency scores for individual items (25 foods rich in VA, C, and carotene) by the nutrient contents of the standard portion, after adjustments were made for the seasonal availability of some foods.

Adult↗
PubMed1984

Case-control study of ovarian cancer in Japan.

A case-control study of 80 women with ovarian epithelial carcinoma and 160 individually age-matched controls were conducted to assess various factors associated with the incidence of ovarian cancer in Hokkaido, Japan. Among the characteristics studied, the following factors were significantly greater in the cases than in the controls: (1) blood group A; (2) never married or married late in life; (3) more frequent surgery for retroflexion of the uterus; (4) less use of contraceptive appliances; and (5) less daily use of cosmetics. It was inferred from these observations that ovarian cancer patients had a genetic predisposition and dysfunctional ovaries. Gonadal dysfunction among ovarian cancer patients presumably explained not only altered personality and behavior patterns, but also facilitated the pituitary gonadotropin activity which has been suggested as increasing the incidence of the disease experimentally.

ABO Blood-Group System↗
PubMed1984

Effect of skim milk and yogurt on serum lipids and development of sudanophilic lesions in cholesterol-fed rabbits.

Three groups of male Japanese rabbits weighing about 2.7 kg each were given experimental diets consisting of high cholesterol food and fluid skim milk, yogurt, or water, and were bled every 4 wk to measure serum lipids. After 12 wk they were killed and concentrations of total cholesterol and atheromatous areas dyed with Oil Red O were determined in the aorta to evaluate the development of atherosclerosis. At 8 and 12 wk, the skim milk group showed significantly lower levels of serum total cholesterol, low-density lipoprotein cholesterol, and triglyceride than the control group. Although no significant difference between the yogurt and control groups in the concentration of serum lipids was observed, total cholesterol concentrations in the aorta were significantly lower in both the skim milk and the yogurt groups than in the control group. The atheromatous areas of the skim milk group (38 +/- 34%) were significantly smaller than those of the control group (75 +/- 25%). Significant difference, however, was not found between the yogurt group (51 +/- 22%) and the control group. Concentrations of total cholesterol in the liver did not differ among the three groups. These results suggest that skim milk may have a preventive effect on the development of atherosclerosis.

Animals↗
PubMed1984

[A chronobiological study on toluene anesthesia in mice].

An experimental study of toluene exposure was performed on mice at various times of the day using the righting reflex and blood concentration as indicators. One hundred and sixty ICR mice were housed 8 mice per cage for 3 weeks with free access to food and water under a dark-light cycle consisting of alternate 12 hr periods of darkness and light: the dark period beginning at 7:00. The exposure was begun when the mice were 8 weeks old. They were exposed to 10,000 ppm of toluene for 40 min at 4:00, 10:00, 16:00 and 22:00, and they were sacrificed at the end of the exposure, after 3 min or after 30 min. The duration of anesthesia was 200.2 +/- 15.4 (sec) at 4:00, 361.1 +/- 21.5 (sec) at 10:00, 335.1 +/- 18.5 (sec) at 16:00 and 309.2 +/- 19.8 (sec) at 22:00. The duration of anesthesia at 4:00 was shorter than that of the other times of the day statistically (p less than 0.01). With regard to the toluene concentration in blood, there was no significant difference between those mice sacrificed at the end of exposure and those sacrificed after 3 min.

Anesthesia, Inhalation↗
PubMed1983

Effects of trichloroethylene exposure on hearing. An investigation of cochlear microphonics and action potential of the guinea pig.

Four groups of guinea pigs with normal Preyer's reflex were exposed to trichloroethylene (TCE). Each group consisted of nine to 10 naive male albino Hartley guinea pigs of 9 weeks of age with a body weight of approximately 400 g. To test the suggestion that TCE causes damage to the cochlear system, a study was conducted involving four experiments. The results were as follows: No significant difference was observed between the intensity functions of the CM (4 kHz) and AP (7 kHz) potentials of the control groups and those of the TCE-exposed groups by analysis of variance. It was considered that there was no difference in the cochlear reaction to high frequency sound between guinea pig and man. It therefore might be suggested that acute exposure to TCE of a high concentration does not always induce dysfunction of the organ of Corti and the 8th nerve in man.

Action Potentials↗