Search PubMed⌕ Search

Biomedical subjects

K Takada

Publications and source records attributed to K Takada.

At least 523 records · Page 29Linked to original sources
PubMed1992

Punishment of schedule-controlled behavior with beta-carboline injections: antagonism and comparisons with other compounds.

Squirrel monkeys were trained to press a key under a multiple schedule of food presentation. In the presence of either green or red stimulus lights, the 30th response produced a food pellet (fixed-ratio schedule). In the presence of the red stimulus lights (punishment component), the first response of each fixed-ratio produced either an i.v. injection of histamine [30.0-100.0 micrograms/kg/injection (inj)] or saline, accompanied by a 200-msec presentation of amber stimulus lights. Sessions in which histamine was injected alternated with sessions in which saline was injected. Another group of subjects was studied under identical schedule conditions except that electric shock was scheduled with the 200-msec stimulus light. During alternate sessions, electric shock at a high or low intensity with the stimulus, or the stimulus alone was scheduled. When performances stabilized, histamine or high intensity electric shock selectively suppressed responding in the punishment component; saline, low intensity electric shock or the stimulus light alone had no effects. Subsequently, different doses of histamine, I-nicotine, cocaine or beta-carboline-3-carboxylic acid ethyl ester (beta-CCE) were substituted for histamine during single sessions. Histamine (17.8-100 micrograms/kg/inj), I-nicotine (32 micrograms/kg/inj) and beta-CCE (10-56 micrograms/kg/inj), but not cocaine (10.0-100.0 micrograms/kg/inj), produced a dose-related selective suppression of responding similar to that obtained with electric shock, suggesting that the drugs were functioning as punishers. Punishment by beta-CCE was antagonized with the benzodiazepine antagonist, flumazenil.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

[Neutrophilic dermatosis in a patient with refractory anemia].

A 46-year-old man diagnosed as refractory anemia was hospitalized because of high fever and extensive erythema with ulceration in the femoral region. His peripheral blood examination showed marked leukocytosis (WBC 31,500/microliter:neutrophilic 90%) and anemia (Hb 8.6 g/dl. In spite of administration of antibiotics, the cutaneous ulcer rapidly extended to the right thigh and became necrotic. The bacterial culture of the cutaneous lesion showed no growth and a skin biopsy showed infiltration of neutrophils in the dermis. He became afebrile and his cutaneous lesion improved after administration of corticosteroid. When the dose of corticosteroid was decreased, cutaneous erythema and nodules appeared at other sites repeatedly, and disappeared after the dose of corticosteroid was increased. The cutaneous lesions had characteristics of both Sweet's syndrome and pyoderma gangrenosum. Moreover, the patient had immunological abnormalities and decreased neutrophilic functions (chemotaxis and O2- generation). Thus, it was suggested that the cutaneous lesions of this patient could be diagnosed as "neutrophilic dermatosis of MDS", and corticosteroid was recognized to be very effective in treating these skin lesions.

Anemia, Refractory↗
PubMed1991

Modified Bielschowsky and immunohistochemical studies on senile plaques in aged dogs.

Aged dogs developed senile plaques (SP) in the brain which were similar to those occurring in aged humans. These SP were studied with a modified Bielschowsky stain and immunohistochemical methods using polyclonal antibodies raised against beta-protein and glial fibrillary acidic protein (GFAP). Serial sections stained by immunohistochemical and modified Bielschowsky stains showed that all areas of slight beta-protein immunoreactivity were intensely stained by the modified Bielschowsky stain. Most SP were observed in the neocortex of the cerebrum. Plaque densities were highest in the cingulate and temporal cortices. There were occasional SP in the subcortical nuclei including the caudate nucleus and putamen, and hippocampus. Based on the morphological characteristics demonstrated by the modified Bielschowsky stain, SP in the brains of the dogs were grouped into 3 types: diffuse, mature and perivascular plaques, of which diffuse plaques were predominant. Various degrees of astroglial reaction were observed in all subtypes of SP except diffuse plaques. These findings indicate that dog may serve as a model for study of the pathogenesis of SP.

Aging↗
PubMed1991

Pravastatin, a HMG-CoA reductase inhibitor, blocks the cell cycle progression but not Ca2+ influx induced by IGF-I in FRTL-5 cells.

IGF-I, when added to the TSH-primed FRTL-5 cells, induces a long lasting Ca2+ influx, and then, DNA synthesis. Moreover, Ca2+ channel agonist, B AY K8644 can mimic these effects on cell proliferation. We studied the effect of HMG-CoA reductase inhibitor, Pravastatin on IGF-I-induced cell cycle progression in FRTL-5 cells. Pravastatin inhibited DNA synthesis induced both by IGF-I and by BAY K8644. In contrast, Ca2+ influx stimulated by IGF-I was unaffected. These data demonstrate that the signal transduction pathway evoked by IGF-I may possibly involve pravastatin-sensitive process at the downstream step of Ca2+ entry. HMG-CoA reductase inhibitors are known to modulate some cellular signal transduction systems by blocking the membrane attachment of low molecular weight GTP binding proteins such as p21ras. Therefore, pravastatin-sensitive process that we have shown here might possibly involve some of such small G protein.

Animals↗
PubMed1991

Carcinogenic effects of bis(2,3-dibromopropyl)-phosphate in Wistar rats.

Four groups of 40 Wistar rats of each sex per dose level were fed diets containing 0, 80, 400 or 2000 ppm of the magnesium salt of bis(2,3-dibromopropyl)phosphate (Bis-BP) for 24 months. A high incidence of tumours was induced, in both sexes, in the digestive system. Tumours included papillomas and adenocarcinomas of the tongue, oesophagus and forestomach, adenocarcinomas of the intestine and hepatocellular adenomas (neoplastic nodules) and carcinomas. Pre-terminal mortalities were associated with an increased incidence of forestomach papillomas in both sexes, adenocarcinomas of the small intestine in male rats and increased incidence of hepatocellular carcinomas in females. The data suggest that Bis-BP is a more potent proximate carcinogen than tris-(2,3-dibromopropyl)phosphate (Tris-BP).

Animals↗
PubMed1991

Family studies of the LDL receptor gene of relatively severe hereditary hypercholesterolemia associated with Achilles tendon xanthomas.

To assess the relationship between relatively severe hereditary hypercholesterolemia with Achilles tendon xanthomas and the defect of the low density lipoprotein (LDL) receptor gene, family studies were carried out in 17 hypercholesterolemic families. In 16 out of the 17 families, hypercholesterolemia co-segregated with four different gross rearrangements, six different restriction fragment length polymorphism (RFLP) haplotypes, or an abnormal TaqI band of the LDL receptor gene. These findings are compatible with the interpretation that hypercholesterolemia is caused by defective LDL receptor genes, and that the origin of the mutant LDL receptor genes in Japanese generally differs among different pedigrees. In the remaining family, the proband and his sibling, both having relatively severe hypercholesterolemia and Achilles tendon xanthomas, shared an RFLP haplotype, although the proband's other sibling with moderate hypercholesterolemia but without Achilles tendon xanthomas did not. The mutant gene for familial defective apolipoprotein B-100 was not detected in the 17 probands. These data suggest that most, if not all, of the relatively severe hereditary hypercholesterolemia associated with Achilles tendon xanthomas is caused by a defect of the LDL receptor gene.

Achilles Tendon↗
PubMed1991

An Epstein-Barr virus-producer line Akata: establishment of the cell line and analysis of viral DNA.

An Epstein-Barr virus (EBV)-producer line, designated Akata, was established from a Japanese patient with Burkitt's lymphoma. The Akata line possessed the Burkitt's-type chromosome translocation, t(8q- ; 14q+), and was derived from the tumor cell. Akata cells produced a large quantity of transforming virus upon treatment of cells with anti-immunoglobulin antibodies (Takada, 1984). Southern blot analysis of viral DNA indicated that the Akata EBV is nondefective and more representative of wild-type viruses. Akata cells should be useful as a source of EBV.

Antibodies, Viral↗
PubMed1991

Changes in ubiquitin and ubiquitin-protein conjugates in the CA1 neurons after transient sublethal ischemia.

Ubiquitin is involved in the degradation of denatured proteins in the recovery process after various stresses. To clarify the different responses of the ubiquitin system in the hippocampal neurons after ischemia, we chose 7.5 min of sublethal forebrain ischemia in the rat. After 7.5 min of ischemia, ubiquitin-like immunoreactivity (UIR) in most of the hippocampal pyramidal cells, except for the interneurons, diminished after 3 h of reperfusion, but enhanced UIR and subsequent recovery of UIR were observed in the different hippocampal regions after 24 h of reperfusion. The most prolonged recovery of UIR in the hippocampal cells was observed in the CA1 neurons after 72 h of reperfusion. Immunoblot analysis of the proteins extracted from CA1 region showed that high-mol-wt ubiquitin conjugates (HMWUC) above 40 kDa increased, whereas free ubiquitin and ubiquitinated histone 2A decreased slightly after 4 h and 24 h of reperfusion. At 72 h of reperfusion, HMWUC decreased to the original level and free ubiquitin slightly increased beyond the control level. These results suggested that (1) diminished UIR does not always mean depletion of entire ubiquitin-protein conjugates; (2) even after sublethal ischemia, damaged proteins in the CA1 neurons may increase, and it may take a long time for elimination of these proteins.

Animals↗
PubMed1991

Changes in facial skin temperature associated with chewing efforts in man: a thermographic evaluation.

Eleven healthy male adults chewed hard and soft chewing-gums for 5 min. A thermographic record of the face on the chewing side was made at the beginning of, during and after the effort. Facial temperature distributions during open/close cyclic unloaded jaw movements were recorded at a later date. The dimensions of the zones whose temperatures were 1.4 degrees C or more higher than the central temperature during the experiment were determined. There was a linear increase in the dimensions of these zones after the chewing. In contrast, the cyclic jaw movements did not result in significant increases. Chewing the hard gum produced significantly higher temperature rises than did the soft in the masseter area. After the chewing effort, the temperature fell gradually, but did not return to the initial state even after 30 min. The overall decreasing pattern of the temperature distribution for chewing the soft gum was similar to that for the hard gum. The facial temperature associated with chewing efforts rose in accordance with the resistance offered by the chewing-gums.

Adult↗
PubMed1991

Early events in Epstein-Barr virus genome expression after activation: regulation by second messengers of B cell activation.

RNA transcription from the BamHI Z and BamHI R and HindIII G regions of the Epstein-Barr virus (EBV) genome was studied after treatment of Akata cells with anti-immunoglobulin G (IgG), with second messenger agonists or antagonists to determine how latent EBV activation is regulated by B cell second messengers. Northern gel analysis demonstrated that BZLF1, BZLF1 + BRLF1, and BMLF1 + BSLF2 transcripts were induced at 2 hr and increased in concentration at 4 hr after induction with anti-IgG; transcripts from BRRF1, BaRF1, BMLF1, and BMRF1 were initiated at 4 hr; a transcript from BRRF2 appeared at 6 hr. The patterns of transcription from these genes after repeated stimulations with calcium ionophore A23187 + dioctanoylglycerol paralleled those with anti-IgG except that times of initiation were delayed by about 2 hr. Nuclear run-off assay of BZLF1 gene showed rapid increases in their transcriptions from 30 to 60 min after anti-IgG treatment. The protein kinase C antagonist, staurosporine, completely blocked the appearance of these transcripts, while 8-bromo cAMP + theophylline suppressed the transcription by about 40%. The regulation of EBV activation in Akata cells with anti-IgG or with second messenger agonists or antagonists can be explained by regulation at the level of transcription of immediate-early genes of EBV.

Alkaloids↗
PubMed1991

Formation of intranuclear replication compartments of Epstein-Barr virus with redistribution of BZLF1 and BMRF1 gene products.

The localizations of the Epstein-Barr virus immediate-early transcriptional activator BZLF1 protein ZEBRA, of the BMRF1 early antigen diffuse component (EA-D), and of viral DNA replication were studied in the Burkitt's lymphoma cell line Akata treated with anti-human immunoglobulin antibodies. Prompt and sequential appearance of ZEBRA, EA-D, and viral DNA was observed in about 70% of the cells. At early times after activation, ZEBRA had a diffuse intranuclear distribution, but later it was concentrated in globular regions within the nucleus. EA-D appeared first in a finely stippled pattern and then in a diffuse pattern. At late times, EA-D concentrated in globular regions similar to those with ZEBRA. Double staining for ZEBRA and EA-D revealed that ZEBRA followed the morphological changes of EA-D with a 1-2 hr delay and that both finally coalesced in the same structures, where in situ hybridization localized replicating viral DNA. The redistribution of both ZEBRA and EA-D to these compartments depended upon the replication of lytic viral DNA. These findings indicate that these globular regions are sites for viral replication and that transcription of EBV late genes may be regulated in these structures.

Animals↗
PubMed1991

Human ovarian cancer cell lines resistant to cisplatin, doxorubicin, and L-phenylalanine mustard are sensitive to delta 7-prostaglandin A1 and delta 12-prostaglandin J2.

The antitumor activity of delta 7-prostaglandin A1 (delta 7-PGA1) or delta 12-prostaglandin J2 (delta 12-PGJ2) on human ovarian cancer cell lines resistant to cisplatin (CDDP), doxorubicin (ADR), and L-phenylalanine mustard (l-PAM) was studied in vitro. A2780AD, A2780 (parent cells of A2780AD), 2008DDP, and 2008 cells (parent cells of 2008DDP) were used. The antitumor activities of the drugs were defined with 50% inhibitory concentration (IC50) estimated from growth inhibition curves, which were obtained by an indirect colorimetric method. Drug-resistance ratios obtained from IC50 values, by comparing A2780AD and A2780 cells, were 62.5 for ADR, 4.6 for CDDP, 4.9 for l-PAM, 1.5 for delta 7-PGA1, and 1.8 for delta 12-PGJ2. Those obtained by comparing 2008DDP and 2008 cells were 1.1 for ADR, 16.0 for CDDP, 2.9 for l-PAM, 2.3 for delta 7-PGA1, and 3.2 for delta 12-PGJ2. Thus some human ovarian cancer cells resistant to ADR, CDDP, and l-PAM remain sensitive to antitumor PGs.

Antineoplastic Agents↗
PubMed1991

Angioscopy of the inferior vena cava: preliminary observations in cases with involvement by neoplasm. Work in progress.

Angioscopy of the inferior vena cava (IVC) was performed in 10 patients. Tumor thrombus extending into the IVC was suspected in six patients, and direct invasion of the IVC wall was suspected in four, based on computed tomographic and venographic findings. In each case, a fiberscope was directed to the area of interest in the IVC via a transfemoral 5-F catheter. Blood displacement by means of a saline infusion enabled angioscopic observation of the IVC wall. The neoplasms were seen clearly in all patients but one. The color and texture of the tumor thrombi surface made it easy to distinguish from the healthy IVC wall. In the four patients believed to have direct invasion of the wall, there were no angioscopic differences between the suggestive areas and adjacent areas of normal IVC wall. In these four cases, the absence of direct invasion was confirmed at surgery. Thus, angioscopy helps make an accurate nonoperative or preoperative diagnosis of tumor thrombi possible and may aid in the exclusion of direct invasion.

Adult↗
PubMed1991

Lipophilic peptides: synthesis of lauroyl thyrotropin-releasing hormone and its biological activity.

Thyrotropin-releasing hormone (TRH) was derivatized by chemical attachment of lauric acid to the N-terminal pyroglutamyl group. The product was confirmed to be more lipophilic than TRH by high-performance liquid chromatography and measurement of partition coefficients. The central nervous system activity and endocrine activity of the lauroyl derivative were only slightly reduced, to 81 and 64% of the parent TRH, respectively. Lipophilic derivatization may be generally applicable to transmembrane delivery of peptides.

Amino Acid Sequence↗
PubMed1991

An evaluation of ovarian carcinoma-associated antigen defined by murine monoclonal antibody CF511 in sera from patients with ovarian carcinoma.

Murine monoclonal antibody CF511, raised against human ovarian clear cell carcinoma, detects a glycoprotein (Mr 600 kDa) called CF511 antigen which is elevated in the serum of many patients with ovarian carcinoma. A competitive enzyme-linked immunosorbent assay was developed to detect CF511 antigen in human serum and used to detected CF511 antigen in subjects with ovarian carcinoma and other diseases. No raised levels (less than 18 unit (U) ml-1) of the antigen were found in the serum of 220 normal individuals or of patients with germ cell tumours (n = 6), granulosa theca cell tumour (n = 1), gastric carcinomas (n = 10) and colo-rectal carcinomas (n = 8). Raised serum levels of CF511 antigen were found in 6/46 patients (13.0%) with benign gynaecological tumours (including endometriosis or ovarian cyst), in 5/7 patients (71.4%) with breast carcinoma and 16/21 (76.2%) lung carcinoma patients. In patients with ovarian carcinoma, 42.3% (11/26) of stage I and II, and 96.0% (24/25) of stage III and IV had levels of greater than or equal to 18 U ml-1. In all patients with serial determination of CF511 antigen levels before and after the surgery, the levels of antigen correlated with the clinical course of disease. Determination of CF511 antigen levels may be useful for detection of ovarian carcinoma as well as lung and breast carcinomas and for monitoring progress of disease and response to therapy.

Antibodies, Monoclonal↗
PubMed1991

The facilitated effect of retinol on rat hepatocarcinogenesis induced by 3'-methyl-4-dimethylaminoazobenzene.

To examine the influence of retinol acetate (retinol, known as an inhibitor of tumor promotion) on 3'-methyl-4-dimethyl-aminoazobenzene (3'MeDAB)-induced hepatocarcinogenesis, rats were fed with a diet containing 0.06% 3'MeDAB for 4 or 7 weeks and then with a normal diet for 21 or 18 weeks. Rats were given retinol (0, 6.25, 12.5 and 25.0 mg/rat, dissolved in DMSO) i.p. every 5 days from the 10th week to the 20th week. As a control, rats were fed a basal diet and given retinol at the same doses as mentioned above. At the 25th week, the incidence of hepatoma (hepatocellular carcinoma and cholangiocarcinoma) of each group was checked. In rats fed diet containing 3'MeDAB for 7 weeks, significant increases in the incidence of hepatoma were seen in retinol-treated groups at various doses. In rats fed 3'MeDAB diet for 4 weeks, all three doses also moderately, though not significantly, increased the incidence of hepatoma. No liver tumor was found in rats fed normal diet followed by treatment with retinol at any dose. Except for slight but detectable elevation of cellular retinoic acid binding protein levels in tumor tissues obtained from rats treated with retinol, no obvious differences in cellular retinol binding protein and gamma-glutamyl transpeptidase in the tumor tissues were observed between retinol-treated and untreated rats. Phytohemagglutinin-induced lymphocyte blastogenesis of the tumor-bearing rats with or without retinol treatment showed approximately 50% inhibition compared with that of rats fed normal diet without retinol treatment. These results indicated that the administration of retinol in the early stages of hepatocarcinogenesis enhanced the tumor induction, possibly due to the fixation of malignant transformation of the cells.

Animals↗
PubMed1991

Nonlinear interpolation of mandibular kinesiographic signals by applying sensitivity method to a GMDH correction model.

The purpose of the present paper was to propose an improved nonlinear interpolation method for estimating distorted kinesiographic recording of interlattice points in space, and to evaluate its correction accuracy. The group method of data handling (GMDH) correction method we have reported previously is essentially different from other geometric correction methods in the sense that the GMDH correction model can be adapted to the measurement environment in which kinesiographic signals are subject to ferromagnetic interferences. Due to its inherent structure, however, our previous GMDH correction model was restricted to kinesiographic signals representing lattice points in space. In this paper, we explored the sensitivity method for GMDH correction modeling. This provides for nonlinear interpolation of kinesiographic signals for interlattice points. Nominals, i.e., true values, of 3-D coordinates of the interlattice points were determined by means of a mandibular jaw movement simulator together with simultaneous recording of distorted kinesiographic signals which corresponded to the nominals. Distorted signals were corrected by the new method of correction modeling. A mean estimation error of 0.16 mm (SD 0.19 mm) was determined for 24 interlattice coordinates. Thus, nonlinear interpolation by the sensitivity method was confirmed to be effective.

Data Interpretation, Statistical↗