[Sonography of joint disorders].
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Adult↗
Biomedical subjects
K Tamai
Publications and source records attributed to K Tamai.
Study of nu d--> micro-pps and nu d--> micro- Delta ++(1232)ns using the BNL 7-foot deuterium-filled bubble chamber.
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Journal Article↗
Assessment of protein kinase C isozymes by enzyme immunoassay and overexpression of type II in thyroid adenocarcinoma.
A two site enzyme immunoassay which quantitatively identifies types I, II, and III of protein kinase C isozymes has been designed. The soluble protein kinase C isozymes were selectively immobilized by type-specific monoclonal antibodies, MC-1a, -2a, and -3a (H. Hidaka et al., J Biol. Chem., 263: 4523-4526, 1988) which bind to the regulatory domain (NH2-terminal side) of protein kinase C. The amount of each isozyme was then determined using a horseradish peroxidase-conjugated polyclonal antibody raised against the COOH-terminal peptide of protein kinase C. By adding increasing concentrations of the antigen, the range of the assay proved to be 0.51-51, 0.081-8.1, and 0.31-31 nM for types I, II, and III, respectively. This sandwich method was used to determine the level of protein kinase C isozymes in rabbit tissues. Type I was mainly present in the cerebrum and cerebellum; the highest amount of type II isozyme was present in blood platelets [26.0 +/- 3.8 (SE) micrograms/g wet tissue]. We compared the protein kinase C isozyme levels in human normal thyroid gland and thyroid cancer tissues and found that type II protein kinase C specifically increased in thyroid cancer tissues. Immunocytochemical examination using MC-2a revealed that the cytoplasm of the cancer cells showed prominent immunoreactivity for type II isozyme.
Adenocarcinoma↗
Specific inactivation of glutathione S-transferases in class Pi by SH-modifiers.
Treatment of Class Pi glutathione S-transferases (GST) such as rat GST P (7-7), human GST pi and mouse GST MII with 0.05-0.1 mM N-ethylmaleimide (NEM) in 0.1 M Tris-HCl (pH 7.8) resulted in almost complete inactivation of these forms, whereas no or less inactivation occurred for GSTs in Class Alpha and Mu under the same conditions. Inactivated GST P lost its S-hexyl-GSH-Sepharose column affinity. About 0.8 mol of [14C]NEM was found to be covalently bound to 1 mol of GST P subunit when 80% of the activity was lost. Similar treatment with N-dimethyl-amino-3,5-dinitrophenyl maleimide, a colored analogue of NEM, followed by trypsin digestion, HPLC and amino acid sequence analysis revealed that one cysteine residue at the 47th position from the N-terminal of the GST P subunit was preferentially modified. Subunits of GST P and GST pi are known to have 4 cysteine residues at the same corresponding positions. The present results suggest that the 47th cysteine residue may be located in the vicinity of the active site of Class Pi GSTs.
Animals↗
An experimental study of nerve regeneration through chemically treated allografts.
We carried out experiments in rabbits to determine whether treating nerve transplants with gradually increasing concentrations of ethanol, ether and ficin would inhibit the graft-host immune reaction to the allograft. After treatment with ethanol, the basal laminar scaffold of the Schwann cell remained intact and there was satisfactory axonal regeneration. The results after additional treatment with ether or ficin did not achieve such good results. Preservation of the basal lamina is considered to be the essential factor in allowing neural regeneration in these circumstances.
Animals↗
Interleukin-1 induces collagenase production by recessive dystrophic epidermolysis bullosa fibroblasts.
We examined the direct effect of interleukin-1 (IL-1) on the collagenase production by epidermolysis bullosa (EB) fibroblasts. Addition of IL-1 at concentrations of 2.5 x 10(-4) units/ml or below in the culture media greatly enhanced collagenase production by two cell lines of recessive dystrophic EB (RDEB) fibroblasts. They produced 4.82 +/- 0.04 to 5.93 +/- 0.39 units/ml of enzyme, as compared to 0.02 +/- 0.07 units/ml in the absence of IL-1. In contrast, collagenase production by two cell lines of dominant dystrophic EB (DDEB) and normal fibroblasts was not, or only slightly, increased up to 0.69 +/- 0.28 units/ml. IL-1 concentrations of 2.5 x 10(-3) units/ml or higher failed to induce collagenase production by all fibroblasts. 3H-thymidine uptake increased by about 110-376% of control after IL-1 treatment. In addition, these data were obtained using fibroblasts of the 13-15 passages, suggesting that the property might be determined genetically. Although RDEB seems to be a wide heterogeneous group, the present data strongly suggest that the property may be specific to and characteristic of some types of RDEB cells.
Cells, Cultured↗
Some properties of gingival 12-lipoxygenase activity in human and dog.
Arachidonate lipoxygenase activity in gingival tissue was investigated and compared with that of enzymes from other sources. 12-lipoxygenase activity was detected in homogenates of human and dog gingiva after 2 min incubation with exogenous arachidonic acid. 12-HETE was the major metabolite in both species. The 12-lipoxygenase activity in homogenates of human gingiva and in platelets was inhibited by EDTA; it recovered after the addition of a divalent cation such as Ca2+. Its activity in dog gingiva and platelets was not affected by the chelator. Gingival 12-lipoxygenase, unlike platelet 12-lipoxygenase, was inhibited by AA861, a possible 5-lipoxygenase inhibitor. These findings suggest that gingival tissue has high levels of 12-lipoxygenase activity, but the enzyme in human gingiva differs from that in the dog in its dependency upon divalent cations, and gingival 12-lipoxygenase differs from the same enzyme in platelets in its sensitivity to an inhibitor.
12-Hydroxy-5,8,10,14-eicosatetraenoic Acid↗
Clinical and microangiographic studies on rupture of the E.P.L. tendon after distal radial fractures.
The authors have treated 14 cases of spontaneous rupture of extensor pollicis longus tendon after fractures of the distal end of the radius, most of which were undisplaced or only slightly displaced. A microvascular study on five cadavers revealed that this tendon is subject to mechanical bending and attrition, has no mesotenon and has a poorly vascularised portion about 5 mm in length, which may be a cause of spontaneous rupture of the tendon.
Adolescent↗
Synthesis and cytostatic activity of the antitumor antibiotic chartreusin derivatives.
In order to overcome the rapid biliary excretion of chartreusin, which diminished its activity when administered iv, a series of 3',4'-O-substituted derivatives of chartreusin were synthesized. Exo-type of 3',4'-O-benzylidene-chartreusin was found active both by ip and iv administration. Therefore, this compound was selected for further modification on its 6-phenol to obtain broader spectra and better pharmacokinetic parameters than the original compound. Several 6-O-acyl-3',4'-O-exo-benzylidene-chartreusins had high antitumor activity against some murine tumors both by iv and po administration.
Aminoglycosides↗
[Effectiveness of TRH analog in a case of early infantile epileptic encephalopathy].
We reported a case of early infantile epileptic encephalopathy (EIEE) due to perinatal hypoxic-ischemic brain damage. This infant had frequent brief tonic seizures in series accompanied by apnea and bradycardia since two days after birth. Her EEG showed a typical suppression burst pattern. We administered PB. VPA and CZP, but could not control her seizures at all. Then, a thyrotropin releasing hormone (TRH) analog, in addition to PB and VPA, was administered intravenously (0.5 mg/day) to her. Three weeks after the administration of this TRH analog, her seizures ceased completely. We suggest that TRH analog therapy should be considered as one of therapeutics for EIEE whose prognosis is expected to be poor.
Age Factors↗
Coordinate regulation of RNAs encoding two isoforms of the rat muscle nicotinic acetylcholine receptor beta-subunit.
The nicotinic acetylcholine receptor (nAchR) mediates communication between nerve and skeletal muscle. The properties, levels and distribution of these receptors change during development of the neuromuscular junction. These changes may be due, in part, to expression of different gene products. We are using nuclease protection experiments and cDNA cloning to identify the RNA transcripts that encode nAchRs in rat muscle. This analysis has identified two beta-subunit mRNAs. Complementary DNAs corresponding to these two RNAs have been isolated from a rat skeletal muscle cDNA library. Based on nucleotide sequence analysis, these RNAs differ by 9 bases in their 5' coding sequence. The levels of both mRNAs change similarly during muscle development and upon denervation of adult skeletal muscle. These two beta-subunit-RNAs probably result from the use of different exon/intron splice sites in the beta-subunit gene.
Animals↗
Transient induction of single GST-P positive hepatocytes by DEN.
The single cells positive for placental glutathione S-transferase (GST-P), detectable in livers of rats soon after treatment with hepatocarcinogens, are possible 'initiated cells', the hypothesis tested in the present series of experiments. No low dose threshold was observed in male Sprague-Dawley rats at different single doses of diethylnitrosamine (DEN) although a plateau was reached between 160 and 200 mg/kg body weight. At the latter single dose approximately 12,400 positive cells/cm3 were observed immunohistochemically in rat livers after one week, the numbers then decreasing to week 8 and thereafter rising again. In the early stages single cells predominated but with time a gradual increase in mini-foci and larger lesions became evident. Application of selection pressure (feeding of diet containing 0.02% 2-AAF plus partial hepatectomy) to rats 2-24 weeks after single DEN-treatment resulted in the formation of large foci positive for GST-P, especially in the early stages, the growth response being less pronounced with time. The number of foci, on the other hand, was correlated with the number of single cells/mini-foci detected in hepatectomy tissue of the same individuals. These results suggest that the early GST-P positive populations could be the precursor for preneoplastic foci and nodules.
Animals↗
A novel stimulating protein of mammalian DNA polymerase alpha.
A DNA polymerase alpha-primase complex, which had been purified by means of immunoaffinity column chromatography, showed little activity in a reaction mixture composed of Tris-HCl buffer, but showed full activity in potassium phosphate buffer. It was found that potassium ion is required for the reaction by the immunoaffinity-purified enzyme. On the other hand, the DNA polymerase alpha purified by the orthodox biochemical method showed full activity in both buffer systems. A protein factor, which could restore the activity of immunoaffinity-purified DNA polymerase alpha-primase complex in the potassium-free reaction mixture, was separated from biochemically purified DNA polymerase alpha. The factor, designated as factor T, was stable to heat up to 70 degrees C, but was sensitive to trypsin. It sedimented at about 4S through a glycerol gradient. SDS-polyacrylamide gel electrophoresis revealed two polypeptide bands at 56 and 54 kDa. By immunoprecipitation, the factor T was shown to be physically associated with DNA polymerase alpha-primase complex. The stimulation was also observed with poly[d(A-T)], primed M13 DNA, and heat-denatured DNA.
Animals↗
Measurement of sarcomere length in situ.
The laser diffraction method was applied to a whole, unisolated muscle of the mouse in order to study the changes in sarcomere length caused by passive movements of joints. The accuracy of measurement of sarcomere lengths in situ by this method was +/- 5.6%. The site-to-site variation in sarcomere length within resting muscle was not affected by stretching of the muscle and the sarcomere length varied in direct proportion to the muscle length (correlation coefficient = 0.805, p less than 0.01). These results agreed with previous observations on resting muscles in vitro.
Animals↗
In situ observation of adjustment of sarcomere length in skeletal muscle under sustained stretch.
Adjustment of sarcomere length to sustained stretch was studied in situ by the light diffraction method applied to the extensor digitorum longus muscle of the mouse. The muscle was stretched maximally (with the ankle and toes in full plantar flexion) and immobilized by a plaster cast: the sarcomere length immediately after stretch was 2.98 microns. After 1, 3, 5, 7, and 14 days of immobilization, the sarcomere length was 2.94, 2.86, 2.83, 2.77 and 2.78 microns, respectively. This shows how a muscle under sustained stretch adapts itself to a new length and explains why the efficiency of muscle function is maintained after limb lengthening.
Animals↗
[Anti-cancer drug resistance and glutathione S-transferases].
Glutathione S-transferase (GST) is a family of multimolecular forms with multi-functions for detoxication of drugs, and certain GST forms have been reported to concern multidrug resistance (MDR) mechanisms of neoplastic cells to anticancer drugs. In this paper, recent studies of GSTs concerning MDR are briefly reviewed, and the problems to be clarified are discussed. The reduced glutathione (GSH) is known to play important roles in the inactivation (detoxication) of the anticancer drugs. Most of them, especially alkylating agents, are conjugated with GSH by GSTs and detoxified, and the peroxides from drugs such as adriamycin are also reduced with GSH and detoxified by the GSH peroxidase activity of certain GST forms. Rat GST-P (GST 7-7) and human GST-pi, both of which belong to Class pi in the species-independent classification of GST, have been known as a marker enzyme for rat and human (pre) neoplastic lesions, respectively. GST-P is increased in rat hepatic preneoplastic foci resistant to cytotoxic agents. GST-pi is also increased not only in cancer cells such as colon carcinoma and non-small cell lung carcinoma, which exhibit "natural resistance" to anticancer drugs, but also increased in breast, ovarian and other tissue carcinomas with increased "acquired resistance" to certain drugs. A few research groups have attempted to confirm by transfection of a vector expressing a GST form such as GST-pi into non-resistant cell lines whether there is a direct relationship between the expression of a specific GST form and the appearance of MDR. However, MDR did not always appear. Recently, it was found in our laboratory that GST-P, GST-pi and even mouse GST II in Class pi, all are very strongly inactivated by SH-modifiers and active oxygens, indicating that these properties may be useful for overcoming MDR, if the forms really are involved with MDR.
Animals↗
[The local cooling effect of anterior chamber irrigation on the blood-aqueous barrier].
Local cooling effect on the breakdown of the blood-aqueous barrier (BAB) following anterior chamber irrigation, including additional direct irritation of the iris, was evaluated fluorophotometrically. The rabbit anterior chamber was irrigated with simulated aqueous humor (S-MA 2) the temperature of which was maintained at 35 degrees C or 10 degrees C. The fluorophotometry was performed before and 4, 24, 48 hours and 7 days after irrigation for 30 or 60 minutes. The temperature changes in the anterior chamber, retrolental vitreous body and posterior retina were also measured with a thermocouple during irrigation at 10 degrees C. The temperature of the anterior chamber and the retrolental vitreous fell to 15.0 degrees C and 28.2 degrees C, respectively, within 30 minutes after starting irrigation, whereas the temperature drop in the posterior retina was only 2.0 degrees C after 60 min. At 4 hours after 60-minute irrigation, the breakdown of the BAB was greater than following 30-minute irrigation. There was no significant difference in the BAB breakdown between eyes irrigated at 10 degrees C and 35 degrees C.
Animals↗
Structural study of immunoaffinity-purified DNA polymerase alpha-DNA primase complex from calf thymus.
The DNA polymerase alpha-DNA primase complex was purified over 17,000-fold to near homogeneity from calf thymus using an immunoaffinity column. Sodium dodecyl sulfate gel electrophoresis revealed three polypeptides with molecular weights of 140, 50 and 47 kDa, in a ratio of 1:2:0.25. The complex showed a sedimentation coefficient of 9.7 S, a Stokes radius of 56 A and a native molecular weight of 250-260 kDa. Taken together, the data suggest that the calf thymus dNA polymerase alpha-DNA primase complex is essentially a heterotrimer of large (140 kDa) and small (50 kDa) subunits in a ratio of 1:2, with a globular conformation. Electron-microscopic studies of the complex revealed a spherical particle of 120 A in diameter, in agreement with the physiochemical results. The binding of the complex to DNA was also demonstrated.
Animals↗