Search PubMed⌕ Search

Biomedical subjects

K Tsukada

Publications and source records attributed to K Tsukada.

At least 217 records · Page 12Linked to original sources
PubMed1991

Molecular cloning and nucleotide sequence of cDNA encoding the human liver S-adenosylmethionine synthetase.

cDNA clone for human liver S-adenosylmethionine synthetase (liver-specific isoenzyme) was isolated from a cDNA library of human liver poly(A)+ RNA. The cDNA sequence encoded a polypeptide consisting of 395 amino acid residues with a calculated molecular mass of 43675 Da. Alignment of the predicted amino acid sequence of this protein with that of rat liver S-adenosylmethionine synthetase showed a high degree of similarity. The coding region of the human liver S-adenosylmethionine synthetase cDNA sequence was 89% identical at the nucleotide level and 95% identical at the amino acid level to the sequence for rat liver S-adenosylmethionine synthetase.

Amino Acid Sequence↗
PubMed1990

Enhanced phosphorylation of a nucleolar 110-kDa protein in rat liver by dietary manipulation.

RNA polymerase 1 activity and nucleolar volume have been reported to increase in hepatocytes from rats fed a protein-free diet. Phosphorylation in vitro of a 110-kDa protein was enhanced in nuclei and nucleoli from livers of rats fed a protein-free diet. In nuclear extracts the 110-kDa protein in heat-treated nuclei was much more phosphorylated than from control liver. In contrast, casein kinase activity in the nuclear extract from control liver was comparable to that from livers of rats fed a protein-free diet. Nuclear extracts from control rat liver and livers of rats fed a protein-free diet were fractionated by DEAE-cellulose column chromatography. Casein kinase II (NII) eluted at around 0.17 M NaCl scarcely phosphorylates the 110-kDa protein. Chromatography of the nuclear extract from livers of rats fed a protein-free diet, but not from control liver, yielded fractions which eluted at 0.21-0.25 M NaCl and predominantly phosphorylated the 110-kDa protein. The phosphorylation of 110-kDa protein was not appreciably affected by a heparin concentration of 5 micrograms/ml, which completely inhibited casein kinase II. In addition, phosphorylation of the 110-kDa protein in liver nucleoli from rats fed a protein-free diet showed a lower sensitivity to heparin than that in control rat liver nucleoli. These results suggest that enhanced phosphorylation of the nuclear 110-kDa protein in livers from rats fed a protein-free diet is due to the induction of a 110-kDa protein kinase distinct from casein kinase II.

Adenosine Triphosphate↗
PubMed1990

Molecular cloning and nucleotide sequence of cDNA encoding the rat kidney S-adenosylmethionine synthetase.

We previously reported the isolation of a cDNA encoding the liver-specific isozyme of rat S-adenosylmethionine synthetase from a lambda gt11 rat liver cDNA library. Using this cDNA as a probe, we have isolated and sequenced cDNA clones for the rat kidney S-adenosylmethionine synthetase (extrahepatic isoenzyme) from a lambda gt11 rat kidney cDNA library. The complete coding sequence of this enzyme mRNA was obtained from two overlapping cDNA clones. The amino acid sequence deduced from the cDNAs indicates that this enzyme contains 395 amino acids and has a molecular mass of 43,715 Da. The predicted amino acid sequence of this protein shares 85% similarity with that of rat liver S-adenosylmethionine synthetase. This result suggests that kidney and liver isoenzymes may have originated from a common ancestral gene. In addition, comparison of known S-adenosylmethionine synthetase sequences among different species also shows that these proteins have a high degree of similarity. The distribution of kidney- and liver-type S-adenosylmethionine synthetase mRNAs in kidney, liver, brain, and testis were examined by RNA blot hybridization analysis with probes specific for the respective mRNAs. A 3.4-kilobase (kb) mRNA species hybridizable with a probe for kidney S-adenosylmethionine synthetase was found in all tissues examined except for liver, while a 3.4-kb mRNA species hybridizable with a probe for liver S-adenosylmethionine synthetase was only present in the liver. The 3.4-kb kidney-type isozyme mRNA showed the same molecular size as the liver-type isozyme mRNA. Thus, kidney- and liver-type S-adenosylmethionine synthetase isozyme mRNAs were expressed in various tissues with different tissue specificities.

Amino Acid Sequence↗
PubMed1990

Heat-shock proteins and nucleolar hypertrophy in the liver of rat infused with methionine-free total parenteral nutrition.

Infusing a methionine-free solution into rats for 7 days resulted in a marked enlargement of liver nucleoli. By the analysis of two-dimensional gel electrophoresis, a spot 'a' (76 kDa, pI 5.3) stained with Coomassie blue was observed to accumulate highly in liver cytosol from rat infused with methionine-free solution. Metabolically labeling experiments with [35S]methionine showed that 'a' was more heavily labeled in primary hepatocytes of rats infused with methionine-free solution than in those of control rat. To ascertain whether 'a' is one of stress proteins, primary hepatocyte cultures were incubated at 42 degrees C for 2 h. 'a' (76 kDa, pI 5.3) was slightly induced in control hepatocytes but not appreciably in hepatocytes from the treated rat. In contrast, two other spots 'b' (74 kDa, pI 5.6) and 'c' (74 kDa, pI 5.3) were highly induced at 42 degrees C in hepatocytes from control and treated rats. The antibody against the consensus sequence peptide of hsp70 family reacted with 'a' (76 kDa, pI 5.3) as well as 'b' and 'c'. Immunoblot analysis revealed that 'a' accumulates highly in hepatocytes of treated rats. These results indicate that infusion of methionine-free solution into rats induces one member of the hsp70 family in hepatocytes.

Amino Acid Sequence↗
PubMed1990

Reversible G1 arrest in the cell cycle of human lymphoid cell lines by dimethyl sulfoxide.

Proliferation of human B- and T-lymphoid cell lines including Raji and Akata cells was found to be arrested at the G1 stage in the cell cycle by dimethyl sulfoxide (DMSO). The G1 arrest by DMSO occurred gradually and was completed within 96 h after addition of 1.5% DMSO concomitantly with a decrease in growth rate. Progression of G1-phase cells containing a larger amount of RNA into S-phase began 9-12 h after removal of DMSO. At 24 h, the DNA pattern of the cell cycle was similar to that of nontreated log-phase cells. The expression of six differentiation markers on the lymphoid cells was not appreciably changed by treatment with DMSO. On the other hand, the expression of transferrin receptor (one of the growth-related markers) on G1-phase cells 96 h after addition of DMSO was decreased to one-fourth that on log-phase cells and was completely restored 24 h after removal of DMSO. These results indicate that DMSO, known as an inducer of differentiation in several myeloid cell lines, acts as an agent inducing G1 arrest in the cell cycle of the lymphoid cells.

B-Lymphocytes↗
PubMed1990

Decreased activities of S-adenosylmethionine synthetase isozymes in hereditary hepatitis in Long-Evans rats.

Isozyme patterns of S-adenosylmethionine synthetase have been measured with or without dimethylsulfoxide in liver of LEC rat hereditary hepatitis. The activities of the alpha- and beta-forms are decreased with age after birth, and decreased to a half level of 36 weeks after birth. Concentration of S-adenosylmethionine in the liver is almost a half level of control rat. However, the activity of glycine- and tRNA-methyltransferases in the liver shows no significant change.

Animals↗
PubMed1990

DNA synthesis in hepatocytes during liver allograft rejection in rats.

We have investigated DNA synthesis in hepatocytes after orthotopic liver transplantation in four rat combinations--DA into DA (isogeneic), DA into PVG (allogeneic, nonrejector), DA into BN (allogeneic, rejector), and DA into (BN X PVG)F1 (allogeneic, intermediate nonrejector). The methods used were assay of thymidine kinase activity in graft homogenate and staining of hepatocytes in liver sections by an antibromodeoxyuridine monoclonal antibody. Both demonstrated increased DNA synthesis in grafts in all combinations except isogeneic, and showed that its intensity and timing paralleled the occurrence of the rejection reaction. The significance of hepatocyte regeneration after liver grafting is discussed.

Animals↗
PubMed1990

Gastroenteritis in suckling mice caused by human rotavirus can be prevented with egg yolk immunoglobulin (IgY) and treated with a protein-bound polysaccharide preparation (PSK).

Oral inoculation of human rotavirus MO strain (serotype 3) into 5-day-old BALB/c mice cause gastroenteritis characterized by diarrhea. Clinical symptoms, histopathological changes in the small intestine, and the detection of rotavirus antigen in enterocytes were all characteristic of rotavirus-induced gastroenteritis. Using this small animal model, passive protection of suckling mice against human rotavirus infection was achieved with the use of immunoglobulin (IgY) from the yolks of eggs of rotavirus-immunized hens. When IgY against a rotavirus strain homotypic to the challenge virus (MO strain) was administered in the mice, complete protection against rotavirus infection was achieved. On the other hand, with oral administration of IgY against a heterotypic strain (serotype 1, Wa strain), a lower protective effect was nevertheless obtained. The four different strains of human rotavirus (Wa, KUN, MO, and ST3) were inactivated in vitro by treatment with PSK, a protein-bound polysaccharide preparation, in a dose-dependent manner. Oral administration of 2.5 mg of PSK caused a therapeutic effect on experimentally MO-infected suckling mice. The antiviral effect of PSK was indicated by the reduction of the duration of diarrhea.

Animals↗
PubMed1990

Antimetastatic and growth-inhibitory effects of N-acetylchitohexaose in mice bearing Lewis lung carcinoma.

N-Acetylchitohexaose, a water-soluble oligosaccharide was found to display a significant antimetastatic effect against Lewis lung carcinoma (LLC) transplanted into C57BL/6 mice, giving rise to a 40-50% inhibition ratio of pulmonary metastasis when administered intravenously (1 mg/kg) on day 6 after the tumor implantation (5 x 10(5) cells/mouse). It was also revealed that this hexaose had a significant growth-inhibitory effect against the local tumor of the same carcinoma (a 20-30% inhibition ratio), showing an enhancing effect on concomitant immunity in local tumor-resected mice. This oligosaccharide was also shown to enhance the tumoricidal effect of splenic T lymphocytes against LLC and P-815 mastocytoma cells and to increase the natural killer activity of splenic T lymphocytes, assayed with YAC-1 cells as the target.

Animals↗
PubMed1990

[Plasmid profiles of aminoglycoside-resistant Pseudomonas aeruginosa].

Three-hundred and eighty-five strains of Pseudomonas aeruginosa were isolated from Gunma University Hospital from 1984 to 1987. Out of these strains, thirty strains (7.8%) were resistant to GM. We investigated antibiograms, serotyping, phage typing, and plasmid profiles of these strains. The following results were obtained. 1) Only one kind of GM-resistant (GMr) plasmid was obtained in 1984. Two kinds of GMr plasmids were found in 1985, and three kinds of GMr plasmids in 1987, respectively. 2) A strain of I-serotype and Hh8-phage type containing the plasmid I (GM-SM-SA-PIPC, Tra-, 22.6Kb or 22.5 Kb) was suspected to cause the nosocomial infection mainly in Departments of Internal Medicine, and a strain of non-serotypable and Hh8-phage type containing the plasmid IV (GM-SM-SA-CP-Hg, Tra+, IncP-2) was suspected to cause the nosocomial infection mainly in Surgical Departments. 3) Plasmid profiles adding to serotyping and phagetyping contribute to the epidemiological analysis of Pseudomonas aeruginosa infection.

Aminoglycosides↗
PubMed1990

[Delayed postanoxic encephalopathy after strangulation--the serial neuroradiological and neurochemical studies].

A 13-year-old boy was the victim of a strangulation attempt. His behavior was normal by the 6th day after the assault. However, from the 7th day, he developed choreoathetosis, dystonia and marked pseudobulbar palsy. CT and T2-weighted MRI at this time revealed a low density and high signal intensity in the region of the bilateral putamen and caudate respectively for the first time. Thereafter, these symptoms and changes in CTs and MRIs subsided gradually over two months. Sequential analysis of CSF for GABA and dopamine during illness revealed reciprocal changes each other with normal recovery. Because of delayed onset of neurological changes, and findings of CSF with reversible symptoms the delayed encephalopathy after strangulation is probably related to biochemical alteration secondary to anoxia in vulnerable basal ganglia.

Adolescent↗
PubMed1990

[Neuroradiological studies of Wilson's disease by computed tomography and magnetic resonance imaging].

Three cases of Wilson's disease were imaged by computed tomography and magnetic resonance. They were characterized by common findings. CT scan showed atrophy of cerebral cortex, caudate head, midbrain and cerebellum, and areas of low absorption in the caudate head, putamen, globus pallidus, posterior limb of internal capsule, thalamus and midbrain. The T2-weighted MRI imaging demonstrated marked hyperintensity in the putamen, retrolenticular part of internal capsule, thalamus and midbrain. In 2 patients, these high intensity areas were decreased by chelating therapy. Improvement of the increased intensity on T2-weighted images led to the suggestion that the area of marked hyperintensity area might be edema or demyelination rather than neuronal loss or cavitation.

Adolescent↗
PubMed1989

Isolation of a cDNA encoding the rat liver S-adenosylmethionine synthetase.

We have isolated cDNA clones encoding the rat liver S-adenosylmethionine synthetase by means of immunological screening from a phage lambda gt 11 expression library containing cDNA synthesized from adult rat liver poly(A)-RNA. The amino acid sequence deduced from the cDNA indicates that the rat liver enzyme for this protein contains 397 amino acid residues and has a molecular mass of 43697 Da. The deduced amino acid sequence of rat liver S-adenosylmethionine synthetase was 68% similar to those of yeast S-adenosylmethionine synthetases encoded by two unlinked genes SAM1 and SAM2. The rat liver S-adenosylmethionine synthetase also shows 52% similarity with the deduced amino acid sequence of the MetK gene encoding the S-adenosylmethionine synthetase in Escherichia coli.

Animals↗
PubMed1989

Brain stem type neuro-Behçet's syndrome. Correlation of enhanced CT scans and MRI during the acute and chronic stage of the illness.

Brain stem type neuro-Behçet's syndrome was studied with enhanced CT and MRI during the acute and chronic stage of the illness. During the acute stage, brain CT revealed a low density lesion in the brain stem extending from the lower pons up to the midbrain ventrolaterally with marginal enhancement effect. T2-weighted image showed a high signal intensity lesion in the brain stem which mainly involved the basis ponti, tegmentum, tectum and cerebral peduncle. During the chronic stage, the lesion became low in signal intensity with T2-weighted image and reduced in its size without enhancement in brain CT. The prolonged relaxation time of the lesions was gradually normalized with steroid treatment. Sequential brain CT with enhancement and MRI study with T1- and T2-weighted images were useful to detect the lesions and to evaluate the activity in the neuro-Behçet's syndrome.

Adult↗
PubMed1989

Tracheal agenesis with bronchoesophageal fistulas--a case report.

Although tracheal agenesis is presently considered to be a rare and fatal anomaly, an increasing number of institutions have been reporting such cases. Reported herein, is a clinical and necropsy report of a premature infant whose tracheal agenesis was associated with broncho-esophageal fistulas and an imperforate anus. Accidental esophageal intubation enabled a perineal anoplasty to be performed under general anesthesia and allowed him to survive for 14 days.

Anus, Imperforate↗