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Biomedical subjects

T Takai

Publications and source records attributed to T Takai.

At least 91 records · Page 5Linked to original sources
PubMed1992

Enhancement of DNA transfection efficiency by heat treatment of cultured mammalian cells.

The expression of genes introduced into various mammalian cell lines was enhanced by raising the temperature of the cells to 42 degrees C for a few hours after DNA transfection. This heat treatment resulted in an up to 10-fold increase in the frequency of the cells that transiently expressed a foreign gene such as that of beta-galactosidase, whereas it had only a limited enhancing effect on the development of stable transformants. By immunotitration analysis, it was confirmed that the enhanced expression of beta-galactosidase activity correlated well with the increase of the enzyme protein. This procedure may have an applicability for augmenting the frequency of transient gene expression in many cell types.

Animals↗
PubMed1992

Morphological differences between hepatocellular carcinoma and hepatocellular carcinomalike lesions.

In an attempt to provide a quantitative basis for differentiation between well-differentiated hepatocellular carcinoma and hepatocellular carcinomalike lesions (focal nodular hyperplasia, regenerative nodular hyperplasia and hepatocellular adenoma), histopathological and morphometrical analyses were performed on 208 cases of various liver diseases with the aid of an image analyzer. As practical indicators for hepatocellular carcinoma, the following six morphometrical features were established: (a) nuclear shape factor of less than 0.93, (b) coefficient of variance of nuclei of more than 5%, (c) average width of trabecular cords greater than three cells, (d) nucleocytoplasmic ratio increased to more than 0.3, (e) cellular density of more than 40 liver cells and (f) individual nuclear dimension larger than 50 microns2. The manifest categories increased with dedifferentiation of cells in hepatocellular carcinoma; the number and degree of cellular and structural atypia became more prominent. Data were analyzed statistically by two multivariate analyses. Logistic analysis was able to correctly separate hepatocellular carcinoma from conditions that were not hepatocellular carcinoma, including hepatocellular carcinomalike lesions. The incidence of 13 descriptive histopathological findings such as fibrous capsule, portal triads and clear-cell clusters were also compared in hepatocellular carcinomalike lesions and hepatocellular carcinomas graded according to Edmondson's classification. Presence of a fibrous capsule, portal triads, mosaiclike patterns and tumor vessels showed statistical differences between hepatocellular carcinomalike lesions and well-differentiated hepatocellular carcinoma by the chi 2 test (p less than 0.005).

Autopsy↗
PubMed1992

Enhancement of antigen-induced interleukin 4 and IgE production by specific IgG1 in murine lymphocytes.

Conalbumin (CA)-specific type 2 helper T cell (Th2) clone, D10G4.1 (D10) produces IL4 when stimulated with varying doses of TNP-CA in the presence of mitomycin C-treated C3H spleen cells or purified B cells as antigen-presenting cells (APC). The production of IL4 was assessed by bioassay and by expression of IL4 mRNA. IL4 production reached maximum at 100 micrograms/ml of TNP-CA, whereas 1 microgram/ml of the antigen induced less than 10% of the maximum level of IL4. This lower level of IL4 production was augmented to the maximum level when monoclonal anti-TNP IgG1 was added to the culture at 0.5-1 microgram/ml. Anti-TNP IgE, but not anti-TNP IgM, was also effective, though IgE was 1/10 as effective as IgG1. IgG1 with an irrelevant specificity and F(ab')2 of anti-TNP IgG1 did not show augmenting effects. Moreover, the enhancement by anti-TNP IgG1 was completely abolished by monoclonal antibody against murine Fc gamma RII, 2.4G2. These results suggest that a low dose of the antigen complexed with IgG1 is focused on APC by means of Fc gamma RII, processed, and presented efficiently to the Th2 clone. On the other hand, the co-culture of D10 with normal C3H B cells in the presence of 1-100 micrograms/ml TNP-CA resulted in polyclonal IgE production. Anti-TNP IgG1 markedly augmented the lower level of IgE production induced by a suboptimal dose of the antigen (1 microgram/ml). This augmentation was shown to be dependent on endogenous IL4 because the enhancement was abolished by monoclonal anti-IL4 (11B11).

Animals↗
PubMed1992

Selective regulation of antigen-specific IgE response by cyclic AMP level in murine lymphocytes.

We have reported that prostaglandin E2 (PGE2) is a selective stimulator of the antigen-specific IgE response [6]. Because PGE2 is known to elevate intracellular cAMP, we investigated the regulatory role of cAMP in the production of antigen-specific IgE. Anti-TNP IgE response was induced by stimulating TNP-KLH-primed BALB/c spleen cells with the same antigen in vitro. Addition of 10-100 microM dibutyryl cAMP (DBcAMP) to the lymphocyte culture resulted in a 2-3-fold increase in anti-TNP IgE response without affecting the production of anti-TNP IgG1 or IgM. Forskolin, a stimulator of adenylate cyclase, also specifically augmented the IgE response. In contrast, 2',5'-dideoxyadenosine, an inhibitor of adenylate cyclase, suppressed IgE production in an isotype-specific manner. These results suggest that IgE synthesis can be selectively modulated by intracellular cAMP level. Enhancement of IgE production by DBcAMP was observed, particularly in highly primed spleen cells, suggesting that IgE-committed B cells are subjected to regulation by cAMP.

Animals↗
PubMed1991

Manometric evaluation of esophageal function in progressive systemic sclerosis with special regard to the disease severity.

A study was conducted to elucidate the relation between the severity of progressive systemic sclerosis (PSS) and the grade of esophageal function disorder, the extent of which was estimated using esophageal manometry. Fifty two patients with PSS were divided into the mild, moderate and severe groups according to the severity score established by the PSS Research Group supported by The Ministry of Health and Welfare of Japan. Primary peristaltic pressure in the esophageal body at 25 to 35cm from the incisors as well as lower esophageal sphincter pressure (LESP), which represents the function of the smooth muscle of the esophagus, were significantly decreased in parallel with the increasing severity of PSS. In contrast, there was no significant difference in upper esophageal sphincter pressure (UESP) or in primary peristaltic pressure at 20cm from the incisors, indicating that the function of striated muscle of the esophagus was not impaired. In addition, even in the mild PSS group without dysphagia (19 cases), primary peristaltic pressure in the esophageal body at 25 to 35cm from incisors was found to be significantly decreased in comparison with the control. Hence, esophageal manometry was useful for early detection of the pathophysiological state of the esophageal function in PSS.

Deglutition Disorders↗
PubMed1991

Two cases of endoscopically identified esophageal cancer of the superficial-slightly depressed type.

We experienced two cases of superficial type esophageal cancer. Case 1 was a 72-year-old man in whom endoscopic examination revealed a slightly protruded, partially reddened and faded area of irregular shape corresponding to 0-IIa + IIc (slightly depressed type) of the endoscopic classification of esophageal cancers. Macroscopically, it was a superficial, ill-defined and non-cicatrized solitary tumor measuring 2.5 x 2.4 cm in size. Histologically it was a monofocal semidifferentiated squamous cell carcinoma of a swelling type of stage 0. Case 2 was 55-year-old man. Endoscopic examination disclosed an almost roundish, smooth-surfaced, flat and dull red area corresponding to IIc (slightly depressed type). Macroscopically it was a superficial, semidefined and non-cicatrized solitary tumor measuring 1.0 x 1.0 cm in size. Histologically it was a monofocal, semidifferentiated squamous cell carcinoma of stage 0. To detect esophageal cancer at an early stage, the endoscopist needs to inspect the mucosa carefully. In case of males aged over 50, the endoscopist would be well advised to employ the dye-spraying method (Lugol staining method) at the endoscopic examination.

Aged↗
PubMed1990

DNA transfection of mouse lymphoid cells by the combination of DEAE-dextran-mediated DNA uptake and osmotic shock procedure.

Several mouse lymphoid cell lines were efficiently transfected with plasmid DNA by a novel method combining DEAE-dextran-mediated DNA uptake and osmotic shock procedure. The cells were first incubated with DNA-DEAE-dextran complex, treated with hypertonic Tris-HCl buffer containing 0.5 M sucrose and 10% poly(ethylene glycol), and then exposed to hypotonic RPMI 1640 medium. This transfection protocol exhibited maximal frequencies of 0.3% and 3.10(-5) for transient gene expression and stable transformation in P3-NSI/1-Ag4-1 cells, respectively.

Animals↗
PubMed1990

Prostaglandin E2 as a selective stimulator of antigen-specific IgE response in murine lymphocytes.

Anti-2,4,6-trinitrophenyl (TNP) IgE antibody response was elicited by stimulating TNP-keyhole limpet hemocyanin-primed murine spleen cells with the same antigen in vitro. The released anti-TNP IgE was assayed by antigen- and isotype-specific enzyme immunoassay developed in our laboratory. When prostaglandin E2 (PGE2) was added to the lymphocyte culture at 10(-7) M, anti-TNP IgE response was augmented two- to fourfold. Interestingly, PGE2 did not affect the production of anti-TNP antibodies belonging to other isotypes including IgM, IgG1, IgG2a, IgG2b, IgG3 and IgA. Moreover, PGE2 showed neither enhancing nor interleukin 4-replacing activities in the polyclonal IgE response by B cells stimulated with lipopolysaccharide and interleukin 4. When endogenous prostaglandin synthesis was inhibited by 10(-6) M indomethacin, the anti-TNP IgE response, but not the corresponding IgG response, was suppressed by 30%-60%. These results suggest a potential role of PGE2 in the up-regulation of the antigen-specific IgE response.

Animals↗
PubMed1990

Cloning and sequence analysis of the cDNA for arachidonate 12-lipoxygenase of porcine leukocytes.

The complete amino acid sequence of arachidonate 12-lipoxygenase (EC 1.13.11.31) of porcine leukocytes was deduced by cloning and sequence analysis of DNA complementary to its mRNA. The sequence was confirmed by automated Edman degradation of the N-terminal regions of the native enzyme and its proteolytic fragments. The cDNA had an open reading frame encoding 662 amino acid residues with a calculated molecular weight of 74,911. Amino acid residues 533-545, Cys-(Xaa)3-Cys-(Xaa)3-His-(Xaa)3-His, showed significant homology to the short cysteine- or histidine-containing sequences proposed as the metal-binding domains of transcription factors and various metal-containing proteins [Berg, J. M. (1986) Science 232, 485-487]. The amino acid sequence of 12-lipoxygenase exhibited 86% identity with human reticulocyte 15-lipoxygenase and showed 41% identity with human leukocyte 5-lipoxygenase. The 12-lipoxygenase cDNA recognized a 3.4-kilobase mRNA species in various porcine cell types, with the largest amount in leukocytes, followed by pituitary, lung, jejunum, and spleen.

Amino Acid Sequence↗
PubMed1989

Cytidylate cyclase activity in mouse tissues: the enzymatic conversion of cytidine 5'-triphosphate to cytidine 3',5'-cyclic monophosphate (cyclic CMP).

Cytidylate cyclase activity, which enzymatically converts cytidine 5'-triphosphate (CTP) to cytidine 3',5'-cyclic monophosphate (cyclic CMP), has been demonstrated in mouse tissue homogenates by use of a highly sensitive enzyme immunoassay (EIA) specific for cyclic CMP. Cyclic CMP formation is dependent on the amount of homogenate and on the incubation time. Although the enzyme activity was detected at wide ranges of pH from 6.8 to 11.5, the maximal activity was observed at around pH 9.4. The optimal temperature was 37 degrees C. Cytidylate cyclase activity was almost completely lost if the homogenates were heated at 90 degrees C for 3 min prior to use. The enzyme reaction exhibited typical Michaelis-Menten kinetics with an apparent Km for CTP of approx. 0.31 mM. Cyclic CMP formation was greatly enhanced with 4 mM Mn2+, Mg2+, Co2+; Mn2+ was the most effective. Fe2+ and Ca2+ were without effect. Cu2+ and Zn2+ at a concentration of 0.1 to 0.5 mM were inhibitory to Mn2+-dependent activity. Moreover, the enzyme activity was inhibited by several nucleotides including ATP, ADP, 5'-AMP, and GTP. Cytidylate cyclase activity was found to be present in all homogenates from a variety of mouse tissues examined except heart, with the highest level found in brain, and the lowest in liver.

Animals↗
PubMed1989

Fat emulsion in surgical patients with liver disorders.

Total parenteral nutrition (TPN) with fat emulsion was evaluated in 68 patients with liver disorders who were admitted to the First Department of Surgery, Osaka City University Medical School. All patients received transabdominal direct operation for esophageal varices. Immediately after their operations, 28 received TPN with carbohydrate and fat emulsion as an energy source (FAT group), and 40 received TPN with only carbohydrate as an energy source (non-FAT group). Liver function tests, blood glucose levels, intravenous fat tolerance tests, serum lipid levels, fatty acid composition of serum total lipids, and nitrogen balance of the two groups were compared during postoperative TPN. The administration of fat emulsion during postoperative TPN in patients with liver disorders did not worsen the results of liver function tests and the relatively low levels of blood glucose were retained, thereby correcting the abnormalities in the fatty acid composition of serum total lipids. Rates of clearance of fat emulsion during postoperative TPN were significantly higher than in the preoperative period, and changes in serum lipid levels revealed no tendency toward retention of fat emulsion administered intravenously. Nitrogen balance and change in body weight during postoperative TPN were similar in both groups. These results suggest that for patients with liver disorders, the administration of fat emulsion is useful during postoperative TPN.

Esophageal and Gastric Varices↗
PubMed1989

Ecology of Vibrio cholerae non-O1 and Salmonella spp. and role of zooplankton in their seasonal distribution in Fukuyama coastal waters, Japan.

Seasonal variation of human pathogens such as Vibrio Cholerae non-01 and Salmonella spp. in Fukuyama coastal waters and the role of zooplankton in their distribution were studies for a period of 1 year. Comparison of two established methods, viz., the elevated temperature method and the two-step enrichment method of enumerating V. cholerae, showed that the former is superior in the recoveries of V. cholerae non-01. Isolation of this pathogen on a wider range of salinities (0.4 to 32.5%) revealed that these organisms are apparently an autochthonous component of the aquatic environment. Temperature appears to be the most crucial element in governing the distribution of V. cholerae non-01. Among the 69 isolates serotyped, 22 different serovars were identified, while one isolate failed to react with any of the known Louisiana State University antisera tested. Zooplankton samples did not harbor more V. Cholerae non-01 than the water column did. Better isolation of an allochthonous pathogen, viz., Salmonella spp., was noticed from the water samples when swabs were employed. Of the 251 isolates serotyped, 18 serotypes with three variants of Salmonella spp. were identified. A high amount of nutrients in the water column increased the survival rate of these pathogens in saline waters as evidenced by a higher incidence of various serotypes in polluted Fukuyama port than in clean marine waters. Salmonella spp. association between V. cholerae non-01 of Salmonella spp. with zooplankton could be noticed as influencing their seasonal distribution.

Animals↗
PubMed1989

[Neuropathological study of the esophagus in cirrhotic patients with esophageal varices].

A neuropathological study was performed in autopsy specimens of the esophagus of 8 cirrhotic patients with large esophageal varices, in which cases marked dilatation as well as motility disorders of the esophagus were demonstrated by esophagography, esophagoscopy and esophageal manometry. Histological findings of the esophagus of cirrhotics were also compared to those of 7 control patients without esophageal or liver disease. Total and normal ganglion cell counts/cm2 at the Auerbach's plexus were found to have been significantly decreased, while the rate of the ganglion cells with the deformity of nucleus or with degenerated Nissl granules significantly increased at the upper, middle and, in particular, lower esophagus. Thus, the reduction of the number of and the degeneration of ganglion cells at the Auerbach's plexus in the esophagus of cirrhotic patients with large varices are clearly demonstrated, and it is further suggested that such neuropathological changes as described above may have contributed to, at least in part, the development of impaired motility of the esophagus with large varices.

Aged↗
PubMed1988

Developmental changes of the content of acetyl-CoA carboxylase mRNA in chicken liver.

Utilizing RNA blot hybridization and immunoblotting techniques, the changes of the hepatic contents of acetyl-CoA carboxylase mRNA and of the enzyme protein in growing chicks have been investigated. In the post-hatching period, the hepatic mRNA level markedly increased at least 70-fold when compared to that before hatching. This increase was not observed in chicks receiving no diet. These changes were closely paralleled with the rise of the hepatic content of acetyl-CoA carboxylase protein in chicks up to 10 days old. Neither the acetyl-CoA carboxylase mRNA level nor the enzyme quantity significantly changed in heart. It is concluded from these results that the developmental regulation of acetyl-CoA carboxylase in the post-hatching period of chicks is tissue specific and occurs primarily at a pretranslational step. The content of acetyl-CoA carboxylase mRNA in adult chicken liver was low, which is comparable to those in embryos at 3 days before hatching and chicks at hatching day. Although acetyl-CoA carboxylase mRNA was detected in adult chicken brain, heart, lung, kidney, uropygial gland, spleen, testis, and chest muscle as well as liver, the mRNA level in these tissues was much lower than that in liver of growing chicks.

Acetyl-CoA Carboxylase↗
PubMed1988

Primary structure of sheep prostaglandin endoperoxide synthase deduced from cDNA sequence.

The complete amino acid sequence of prostaglandin endoperoxide synthase from sheep vesicular gland has been deduced by cloning and sequence analysis of DNA complementary to its messenger RNA. The results were confirmed by digestion of the enzyme with carboxypeptidase Y and by automated Edman degradation of the intact enzyme polypeptide and peptide fragments obtained by limited proteolysis of the enzyme with Achromobacter proteinase I. Mature sheep prostaglandin endoperoxide synthase is shown to be composed of 576 amino acids with an Mr of 66,175. The precursor peptide is predicted to contain a 24-residue signal peptide. The serine residue susceptible to acetylation by aspirin is found to be located near the C-terminus of the enzyme polypeptide.

Amino Acid Sequence↗