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T Tada

Publications and source records attributed to T Tada.

At least 271 records · Page 15Linked to original sources
PubMed1990

Analysis of age-related degeneracy of T-cell repertoire: localized functional failure in CD8+ T cells.

The repertoire and frequency of alloreactive T cells in aged mice were examined by limiting dilution analysis of the mixed-lymphocyte reaction (MLR). Mice were aged in specific pathogen-free conditions up to 31 months, and MLR of their spleen cells under limiting dilution conditions was examined at various stages of ageing. The frequency of alloreactive T cells was found to decrease in mice more than 14 months of age, and the value reached about 1/3 of that of young mice of 2 months of age. The slope analysis of cell dose-response curves of MLR indicated the existence of two interacting T-cell populations, i.e. CD4+ and CD8+, cooperation between which is required for the full manifestation of MLR in limiting dilution conditions. The decrease in the alloreactivity of aged spleen cells was ascribed to the selective functional loss of the CD8+ population, because the CD4+ but not the CD8+ T-cell fraction from aged mice could restore the limiting factor in MLR. The decrease in the cooperative activity of CD8+ T cells in allo-MLR starts much earlier than the decrease in the number of CD8+ T cells in the spleen.

Aging↗
PubMed1990

Ultrastructural and histological studies on closure of the mouse ductus arteriosus.

The ductus arteriosus in mice was studied by light and electron microscopy for a certain time span (from day 15 of gestation to 16 weeks after birth). In the intima, subendothelial intimal cells began to appear at day 17 of gestation, while actual constriction of the ductus arteriosus progressed rapidly after birth, beginning always at the site adjacent to the ductus arteriosus-aorta junction. At 3 h postnatally, the ductus arteriosus showed complete occlusion (functional closure), which was due mainly to constriction of the medial smooth muscle cells. At this stage, intimal cells (endothelial and subendothelial intimal cells), which occupied the ductal lumen, demonstrated ultrastructural features of undifferentiated cells. However, all the intimal cells 3 weeks after birth and thereafter were revealed to have electron-microscopic features of mature smooth muscle cells. The smooth muscle cells of the media and intima decreased progressively in number with advancing deposition of stromal collagen and elastic fibers in the ductal wall.

Animals↗
PubMed1990

Age-related degeneracy of T cell repertoire: influence of the aged environment on T cell allorecognition.

The present study was undertaken to understand the mechanism of alteration of the alloreactivity of T cells in aged mice. The experiment utilized bone marrow chimeras revealed that the age-associated changes in alloreactivity are not primarily determined by the bone marrow stem cells but determined by the environment where stem cells differentiate into mature T cells. The limiting dilution analysis and microfluorometry analysis indicated that the changes lie in both frequency of alloreactive T cells and the expression of T cell antigen receptor. Such quantitative and qualitative changes seems to be the causes for declined alloreactivity of T cells in aged mice.

Age Factors↗
PubMed1990

Epitope-specific regulation of the antibody response against alpha-lactalbumins in the mouse.

The immune responsiveness to human and bovine alpha-lactalbumin (HuALA and BoALA) was found to be under the control of immune response (Ir) gene(s) linked to the major histocompatibility complex. H-2k mice responded to both HuALA and BoALA, whereas H-2d,s,and f mice respond only to HuALA; H-2b mice were nonresponders to both HuALA and BoALA. A survey with B10.A recombinant mouse strains enabled us to map the Ir gene in the I-A subregion. The responsiveness was shown to be dominant in F1 mice. The coimmunization of BoALA and HuALA resulted in the suppressed secondary antibody response to HuALA in B10.S (H-2s) and BALB/c (H-2d) but not in C3H (H-2k) suggesting that the low responsiveness against HuALA in these strains is due to an active suppression. The transfer of splenic T cells of B10.S mice primed with BoALA into syngeneic animals suppressed the response to HuALA. T cells specific for a particular epitope present on BoALA appeared to suppress the immune response to other epitopes on HuALA. Thus, the presence of epitope-specific suppressor T cells seems to account for this Ir-gene-controlled low responsiveness to ALA in H-2s mice.

Amino Acid Sequence↗
PubMed1990

Study on digestibility and energy availability of daily food intake in Japanese (Part 3. Cereals).

Four male Japanese were fed a semisynthetic diet including egg and soy powder as protein source for seven days (Basal-diet period), and in the following seven days 200 g of polished rice, wheat flour and buckwheat flour added at the expense of part of the corn starch and sugar in the basal diets (Test-diet period). Urine and feces were collected throughout both periods and the contents of nitrogen, fat and energy in these excreta were determined. Digestibility of protein (N), fat and carbohydrate (by difference) was calculated. The protein digestibilities of the polished rice (in the form of cooked grains), wheat flour (in the form of cooked powder) and buckwheat flour were 89.6 +/- 5.0%, 93.4 +/- 2.9% and 85.1 +/- 2.5%, respectively. The fat digestibilities of the polished rice, wheat flour and buckwheat flour were 93.6 +/- 1.8%, 70.8 +/- 13.5% and 103.1 +/- 8.4%, respectively showing relatively large variation (This results may be caused by an errors in measurement). The carbohydrate digestibility was close to 100%. The net energy availabilities of the polished rice, wheat flour and buckwheat flour were 100.6 +/- 1.4%, 96.5 +/- 1.1% and 96.0 +/- 1.1%, respectively.

Adult↗
PubMed1990

Hemangioblastomas of the central nervous system--immunohistochemical and ultrastructural study.

Immunohistochemical studies using immunoperoxidase staining for glial fibrillary acidic protein (GFAP), S-100 protein, and factor VIII-related antigen (VIII-RAg) were performed on 10 hemangioblastomas of the central nervous system to determine the origin of stromal cells. No cytoplasmic immunoreactivity for anti-GFAP, anti-S-100 protein, or anti-VIII-RAg was detected in most stromal cells. A small number of GFAP-positive cells were found only in the periphery of the tumor; they were thought to be trapped astrocytes or stromal cells taking up GFAP. Most stromal cells had abundant, clear cytoplasm with some microfilaments and lipid vacuoles. Cylindrical cytoplasmic processes and intermediate junctions were observed in some stromal cells, but most cells did not possess any junctional device. No stromal cell possessed any feature clearly suggesting endothelial cells or pericytes. Our immunohistochemical and ultrastructural investigations did not support the theories of stromal cell origin from astrocytes or endothelial cells. We concluded that stromal cells can be regarded as an aberrant cell type of angiogenic mesenchymal derivation.

Adolescent↗
PubMed1990

[Congenital anomalies of the coronary arteries with associated ischemic ST depression on exercise: a report of three cases].

This report presented evidence of myocardial ischemia as the etiology of angina pectoris in three patients with congenital anomalies of the coronary arteries but without arteriosclerotic disease. All of three cases showed angina pectoris and ST depressions on their exercise electrocardiogram. Case 1: This 58-year-old man developed angina pectoris at the age of 50 years. His treadmill exercise test precipitated chest pain and ST depression. His coronary arteriograms disclosed an ectopic origin of the right coronary artery just anterior to the origin of the left coronary artery in the left coronary sinus. No significant atherosclerotic stenosis was present. An apparent ischemic manifestation appeared to be caused by compression of an aberrant right coronary artery between the aorta and the right ventricular infundibulum. Case 2: A 49-year-old woman had a history of angina. Her treadmill exercise test induced chest pain and an abnormal exercise electrocardiographic finding. Her coronary arteriograms revealed a single left coronary artery. Insufficient perfusion was postulated as a cause of apparent myocardial ischemia in this case though angiographically, there was adequate perfusion. Case 3: This 31-year-old man had a six-year history of angina. His treadmill exercise electrocardiograms revealed ischemic changes accompanied by chest pain. Coronary arteriograms disclosed a coronary artery fistula. The ischemic manifestation was apparently caused by inadequate perfusion due to coronary steal. With the increasing use of coronary arteriography, unusual origins and courses of coronary arteries will be more frequently encountered. Precise knowledge of anomalies is prerequisite for evaluating variations in the location of the coronary artery ostia and their statistical probabilities.

Adult↗
PubMed1990

[Dissecting aneurysm of the vertebral artery as a cause of Wallenberg's syndrome].

Although it is well known that Wallenberg's syndrome is caused by occlusion of the vertebral artery (VA) or the posterior inferior cerebellar artery (PICA), the etiology of the occlusion is rarely documented. During the course of Wallenberg's syndrome, patients often complain of headache. We thought that these headaches might be caused by dissecting aneurysm (DA) of the vertebral artery, and so we studied the incidence of DA in our cases with Wallenberg's syndrome. Although many variants exist, Wallenberg's syndrome encompasses several neurological symptoms due to a disorder of the nucleus and nerve tracts located in the lateral part of the medulla. We diagnosed our patients as having Wallenberg's syndrome on the basis of symptoms such as loss of pain and temperature sensation in the unilateral face and contralateral body, cerebellar ataxia, and dysphasia. We investigated 22 cases of Wallenberg's syndrome over a five-year period, and excluded patients who developed subarachnoid hemorrhage upon onset of the syndrome. Our cases can be divided into two groups; one with severe stenosis or occlusion of VA (n = 15) and the other with occlusion of PICA (n = 5). The angiograms of the two remaining patients showed no abnormal findings. The mean age of the VA group (42.5 yrs.) was younger than that of the PICA group (64.2 yrs.). The age distribution of the PICA group is similar to that of other occlusive cerebrovascular diseases. Seven cases of the VA group demonstrated aneurysmal dilatation and luminal stenosis, and so they were diagnosed as having dissecting aneurysm of VA.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

Adenocarcinoma arising in Barrett's esophagus after total gastrectomy.

A 64-yr-old Japanese male who underwent a partial gastrectomy for a duodenal ulcer at the age of 21, a total resection of the remnant stomach for a stomal ulcer at age 25, and in whom Barrett's esophagus was diagnosed at age 47, was found to have a tumor at the distal esophagus and was operated on by thoracic esophagectomy. The tumor was a well to moderately differentiated adenocarcinoma invading down to the muscularis propria. The entire esophageal mucosa in the resected specimen was lined by columnar epithelium. This tumor was thought to derive from the Barrett's esophageal epithelium.

Adenocarcinoma↗
PubMed1990

[Changes in content of excitatory amino acids in the brain and cerebrospinal fluid].

Recently epilepsy is analysed on terms of two different conditions, seizure susceptibility and seizure induction. Much attention has been paid to excitatory amino acids in these conditions. An examination was made of changes of glutamate and aspartate in the brain and cerebrospinal fluid (CSF) in a cat amygdaloid kindling model so as to determine whether excitatory amino acids are possibly involved in seizure susceptibility and seizure induction. Twenty crossbred adult cats were divided into four groups: a sham operation group (Sh) as the control, just after stage 4 seizure group (S4), just after stage 6 seizure group (S6), and stage 6 group 2 weeks after the last stimulation (S6-2W). CSF, blood and 13 individual brain regions were taken at 9 + 4 degrees C, and their glutamate and aspartate contents were measured by high performance liquid chromatography (HPLC). Glutamate concentration was significantly higher in the S6 group than in the Sh group in CSF and less in the S6 group than in the Sh group in the left and right amygdala, hippocampus and piriform cortex. No aspartate could be detected in the CSF of any group, nor did it change significantly in the blood or brain. Based on the above results, the content and release of glutamate and aspartate apparently do not change in seizure susceptibility and glutamate is released from kindled tissues in seizure induction, thus showing it to be involved in seizure induction in a cat amygdaloid kindling.

Animals↗
PubMed1989

[A case report of Refetoff's syndrome].

An 11-year-old girl with diffuse goiter is presented. She had no clinical evidence of thyrotoxic symptoms or signs of palpitation, excessive sweating, tachycardia or finger tremor. Both the serum T4 (24.0 micrograms/dl) and T3 (282ng/dl) were high, and thyroid 131I uptake rate (63.2%) was significantly elevated, but T3/T4 ratio was not elevated (11.8). BMR was measured three times and remained within normal limits. Her serum TSH was 1.9 microU/ml, and a TRH stimulation test resulted in a normal rise of serum TSH (13.4 microU/ml). The TSH secretion was not suppressed by medication (p.o.) of 75 micrograms of L-triiodothyronine given for 8 days. The autoantibodies of T4, T3 and TSH were negative. No sign of pituitary tumor was observed by plain X-ray film. No defect in her sight-field was found. From these clinical figures and data, Refetoff's syndrome was suspected. She was eumetabolic without any treatment, but the goiter gradually enlarged and dysphagia developed. A large dose of L-thyroxine (450 micrograms/day) was given for a period of one year and four months. She has been eumetabolic. Her goiter disappeared and the dysphagia completely subsided. After she was given large doses of L-T4, her serum TSH was reduced to 0.07 microU/ml and was slightly elevated to 0.24 microU/ml at 30 min after i.v. infusion of 500 micrograms TRH. Thyroid 123I uptake rate was suppressed to 8.3%. According to Refetoff's papers, this case was classified as being in the group with generalized resistance to thyroid hormone.

Child↗
PubMed1989

Generation of T cell repertoire. Two distinct mechanisms for generation of T suppressor cells, T helper cells, and T augmenting cells.

The present studies were carried out to characterize the influence of the T cell maturation environment on a repertoire of Th cells, T augmenting cells, and Ts cells, which were shown to construct a minimal regulatory circuit to regulate a helper function of class II-restricted Th cells. A repertoire of keyhole limpet hemocyanin-specific Th cells was influenced predominantly by I-A molecules of the T cell maturation environment, whereas a repertoire of T augmenting cells was determined by both I-A and I-E molecules. These repertoires were not influenced by the priming with Ag. A repertoire of Ts cell factor-producing Ts cells was not influenced by the T cell maturation environment, but rather was determined by the I-J haplotype of the APC utilized for priming with Ag. In contrast, a repertoire of novel cognate type Ts cells, which inhibit class II-restricted Th cell function in a restriction-restricted manner, was influenced by both I-A and I-E molecules of the T cell maturation environment. These results demonstrate the two distinct mechanisms for generating a T cell repertoire: a selection by class II molecules of the T cell maturation environment before the priming with foreign Ag and a selection by priming with APC and Ag.

Animals↗
PubMed1989

Autocrine growth and tumorigenicity of interleukin 2-dependent helper T cells transfected with IL-2 gene.

We introduced a mouse IL-2 cDNA expression vector into an IL-2-dependent mouse helper T cell line HT-2. Transfected cells secreted substantial amounts of IL-2, to which they themselves responded by proliferating without further requirement for exogenous IL-2. The proliferation was a direct function of the cell density and was inhibitable by antibodies against IL-2 or IL-2-R, indicating the autocrine nature of the proliferation. Those producing higher amounts of IL-2 were found to be tumorigenic when inoculated into nude mice. The latency period of tumor development correlated inversely with the level of IL-2 secreted. Tumor cells proliferated in vitro in an IL-2 autocrine fashion indistinguishable from that of the inoculated cells. We thus provide evidence that the aberrant activation of the IL-2 autocrine circuit can lead T cells to malignant transformation.

Animals↗
PubMed1989

Polymorphism of T-cell receptor genes among laboratory and wild mice: diverse origins of laboratory mice.

Southern blots of genomic DNA from 23 strains of laboratory mice and 19 individual wild mice were examined for restriction fragment length polymorphisms in their loci encoding the T-cell receptors (Tcr): the constant regions of the alpha, beta, and gamma chains (C alpha, C beta, and C gamma) and a variable region family of the beta chain (V beta 8). Only a few polymorphisms were observed for each locus in the laboratory mice after using three restriction enzymes, Bam HI, Eco RI, and Hind III. All the laboratory mice examined fall into one of two types for the C alpha, C beta, and V beta 8 loci and one of three types for the C gamma. These types are found in some of the wild mice studied, indicating that they were already present in the founder mice of laboratory mouse strains. In contrast, the Tcr genes are highly polymorphic among wild mice. Analysis of the polymorphisms in these loci suggests that laboratory mice have inherited their genes not only from Mus musculus domesticus, but also from other subspecies, and much more than previously believed from Asian subspecies.

Animals↗
PubMed1989

Biochemical identification of I-J as a novel dimeric surface molecule on mouse helper and suppressor T cell clones.

A monoclonal anti-I-Jk antibody JK10-23 was capable of precipitating the putative I-Jk molecule from NP-40 lysates of 125I-surface labelled mouse T cell clones with either helper or suppressor functions. The I-J molecule detected by specific immunoprecipitation and subsequent one- or two-dimensional gel analysis was a Mr 84-90 K dimer composed of 42-46 K glycopeptide subunits having isoelectric point pH 5.3 to 6.4. A monomeric form of I-J also existed in some of the T cell clones. The I-J subunit was a glycosylated polypeptide with a 41 K backbone having at least two glycosylation sites. I-J was distinguishable from other known dimeric T cell surface molecules with comparable molecular size, that is, T cell receptor alpha beta heterodimer, A1 and YE molecules expressed on a T cell leukemia EL4, and mouse CD28. The I-Jk molecule was precipitable from T cell clones with I-Ak and I-Ek restriction specificities including a clone derived from an H-2b----H-2bxkF1 radiation bone marrow chimera. None of the H-2b-restricted T cell clones from H-2b and its F1 showed the I-Jk immunoreactivity. T cell clones having either I-Ab or I-Ek restriction specificities derived from intra-H-2 recombinant mouse B10.A(5R) were positive for the I-Jk, while an I-Ab-restricted T cell clone from B10.A(3R) was negative in the I-Jk immunoprecipitation. The results indicate that I-J is a novel dimeric surface molecule, most likely to be a homodimer, expressed on T cells according to the major histocompatibility complex.

Acetylglucosaminidase↗
PubMed1989

Post-transcriptional allelic exclusion of two functionally rearranged T cell receptor alpha genes.

We cloned and sequenced T cell receptor (TCR) alpha and beta chain cDNA from a lambda gt10 library obtained from a murine I-Ak autoreactive helper T cell clone MS202. Two types of cDNA clones for the alpha chain and one for the beta chain were obtained. The two alpha chain transcripts used two different V alpha genes: V alpha 4, joined to J alpha 11.2; and V alpha 5, J alpha TA13. The four V alpha 4 cDNA clones obtained did not have a complete sequences, lacking the leader portion. The V alpha 4 genomic gene segment of MS202 was revealed to contain two exons corresponding to the V alpha 4.MD13 cDNA sequence, and the potential RNA splicing signals between the two exons were intact. Both of the alpha chain cDNA clones showed in-frame rearrangements. Immunoprecipitation of 125I-surface-labeled lysate of MS202 with anti-TCR antiserum and subsequent electrophonetic analyses indicated that only one of the alpha chain polypeptides was expressed on the cell surface. Thus, allelic exclusion of the alpha chain in MS202 is achieved by post-transcriptional regulation rather than rearrangements.

Alleles↗
PubMed1989

Unidirectional inhibition of early signal transduction of helper T cells by cloned suppressor T cells.

Early intercellular events occurring in cloned T helper (Th) cells following interaction with cloned T suppressor (Ts) cells were studied by stopped-flow fluorometry. It was found that the increase of intracellular Ca2+ ([Ca2+]i) in major histocompatibility complex (MHC)-restricted Th clones induced by the stimulation with antigen and antigen-presenting cells (APC) is inhibited by the incubation with antigen-activated Ts clones. Optimal suppression required that the two cells recognize antigen on the same APC, although the restriction element for recognition could be different. There was an absolute requirement for recognition of the same antigen by these two cell types. The inhibitory effect was unidirectional in that Ts clones could inhibit the increase of [Ca2+]i of Th clones but not vice versa. Ts clones could not suppress the [Ca2+]i response of other Ts clones. If Th and Ts clones do not share the same MHC restriction specificity, a longer co-incubation time for activation of Ts is required for the inhibition of the [Ca2+]i response of the Th clone, suggesting the presence of a non-specific suppressive mediator that selectively acts on Th.

Animals↗