Biomedical subjects

K Tanida

Publications and source records attributed to K Tanida.

At least 19 recordsLinked to original sources

PubMed2003

High resolution spectroscopy of the 12Lambda B hypernucleus produced by the (e,e'K+) reaction.

High-energy, cw electron beams at new accelerator facilities allow electromagnetic production and precision study of hypernuclear structure, and we report here on the first experiment demonstrating the potential of the (e,e'K+) reaction for hypernuclear spectroscopy. This experiment is also the first to take advantage of the enhanced virtual photon flux available when electrons are scattered at approximately zero degrees. The observed energy resolution was found to be approximately 900 keV for the (12)(Lambda)B spectrum, and is substantially better than any previous hypernuclear experiment using magnetic spectrometers. The positions of the major excitations are found to be in agreement with a theoretical prediction and with a previous binding energy measurement, but additional structure is also observed in the core excited region, underlining the future promise of this technique.

Journal Article↗

PubMed2002

Sigma-nucleus potential in A=28.

We have studied the (pi(-),K+) reaction on a silicon target to investigate the sigma-nucleus potential. The inclusive spectrum was measured at a beam momentum of 1.2 GeV/c with an energy resolution of 3.3 MeV (FWHM) by employing the superconducting kaon spectrometer system. The spectrum was compared with theoretical calculations within the framework of the distorted-wave impulse approximation, which demonstrates that a strongly repulsive sigma-nucleus potential with a nonzero size of the imaginary part reproduces the observed spectrum.

Journal Article↗

PubMed2002

Hypernuclear fine structure in (9)(lambda)Be.

With a germanium detector array (Hyperball), we observed two gamma-ray peaks corresponding to the two transitions (5/2(+)-->1/2(+) and 3/2(+)-->1/2(+)) in the (9)(Lambda)Be hypernucleus which was produced by the 9Be(K-,pi(-)) reaction. The energies of the gamma rays are 3029 +/- 2 +/- 1 keV and 3060 +/- 2 +/- 1 keV. The energy difference was measured to be 31.4(+2.5)(-3.6) keV, which indicates a very small Lambda-spin-dependent spin-orbit force between a Lambda and a nucleon. This is the smallest level splitting by far ever measured in a hypernucleus.

Journal Article↗

PubMed2001

Role of SEREX-defined immunogenic wild-type cellular molecules in the development of tumor-specific immunity.

Recognition of altered self-antigens in tumor cells by lymphocytes forms the basis for antitumor immune responses. The effector cells in most experimental tumor systems are CD8(+) T cells that recognize MHC class I binding peptides derived from molecules with altered expression in tumor cells. Although the need for CD4(+) helper T cells in regulating CD8(+) T cells has been documented, their target epitopes and functional impact in antitumor responses remain unclear. We examined whether broadly expressed wild-type molecules in murine tumor cells eliciting humoral immunity contributed to the generation of CD8(+) T cells and protective antitumor immune responses to unrelated tumor-specific antigens [mutated ERK2 (mERK2) and c-erbB2/HER/neu (HER2)]. The immunogenic wild-type molecules, presumably dependent on recognition by CD4(+) helper T cells, were defined by serological analysis of recombinant cDNA expression libraries (SEREX) using tumor-derived lambda phage libraries screened with IgG antibodies of hosts bearing transplanted 3-methylchoranthrene-induced tumors. Coimmunization of mice with plasmids encoding SEREX-defined murine wild-type molecules and mERK2 or HER2 led to a profound increase in CD8(+) T cells specific for mERK2 or HER2 peptides. This heightened response depended on CD4(+) T cells and copresentation of SEREX-defined molecules and CD8(+) T cell epitopes. In tumor protection assays, immunization with SEREX-defined wild-type molecules and mERK2 resulted in an inhibition of pulmonary metastasis, which was not achieved by immunization with mERK2 alone.

Animals↗

PubMed2001

Observation of a (6)(LambdaLambda)He double hypernucleus.

A double-hyperfragment event has been found in a hybrid-emulsion experiment. It is identified uniquely as the sequential decay of ( 6)(LambdaLambda)He emitted from a Xi(-) hyperon nuclear capture at rest. The mass of ( 6)(LambdaLambda)He and the Lambda-Lambda interaction energy DeltaB(LambdaLambda) have been measured for the first time devoid of the ambiguities due to the possibilities of excited states. The value of DeltaB(LambdaLambda) is 1.01+/-0.20(+0.18)(-0.11) MeV. This demonstrates that the Lambda-Lambda interaction is weakly attractive.

Journal Article↗

PubMed2001

Production of (4)(double Lambda)H hypernuclei.

An experiment demonstrating the production of double-Lambda hypernuclei in (K(-),K(+)) reactions on (9)Be was carried out at the D6 line in the BNL alternating-gradient synchrotron. The technique was the observation of pions produced in sequential mesonic weak decay, each pion associated with one unit of strangeness change. The results indicate the production of a significant number of the double hypernucleus (4)(double Lambda)H and the twin hypernuclei (4)(Lambda)H and (3)(Lambda)H. The relevant decay chains are discussed and a simple model of the production mechanism is presented. An implication of this experiment is that the existence of an S = -2 dibaryon more than a few MeV below the double Lambda mass is unlikely.

Journal Article↗

PubMed2001

Observation of spin-orbit splitting in lambda single-particle states.

The spin-orbit splitting of Lambda single-particle states in (13)(Lambda)C was measured. The 13C(K-,pi(-))(13)(Lambda)C reaction was used to excite both the 1/2(-) and 3/2(-) states simultaneously, which have predominantly 12C(0(+)) x p(Lambda) configuration. gamma rays from the states to the ground state were measured in coincidence with the pi(-)'s, by which ls splitting was found to be 152+/-54(stat)+/-36(syst) keV. The value is 20-30 times smaller than exhibited by the ls splitting in the nuclear shell model. This value gives us new insight into the YN interaction.

Journal Article↗

PubMed2001

Measurement of the B(e2) of (7)(lambda)Li and shrinkage of the hypernuclear size.

We report on the first measurement of a hypernuclear gamma-transition probability. gamma rays emitted in the E2(5/2(+)-->1/2(+)) transition of (7)(Lambda)Li were detected by a large-acceptance germanium detector array (Hyperball), and the lifetime of the parent state ( 5/2(+)) was determined by the Doppler shift attenuation method. The obtained result, 5.8(+0.9)(-0.7)+/-0.7 ps, was then converted into the reduced transition probability [ B(E2)] to be B(E2;5/2(+)-->1/2(+)) = 3.6+/-0.5(+0.5)(-0.4) e(2) fm(4). Compared with the B(E2) of the corresponding E2(3(+)-->1(+)) transition in the 6Li nucleus, our result gives evidence that the size of the 6Li core in (7)(Lambda)Li is smaller than the 6Li nucleus in the free space.

Journal Article↗

PubMed2001

Nucleotide sequence of BamHI family satellite DNA and its unit length polymorphism in bluegill sunfish Lepomis macrochirus.

We have isolated and sequenced a member of tandem repetitive DNA containing BamHI site (BamHI family satellite DNA) from bluegill sunfish Lepomis macrochirus. PCR amplification with specific primers was performed to define the size of unit length repeat of the BamHI family satellite DNA, revealing that there were two distinct size of DNA fragments (0.9 kb and 1.3 kb) in the PCR products. The longer fragment (1.3 kb) consisted of internal sub-duplication of shorter fragment (0.9 kb). We have compared the size of PCR products among four fish populations, and found that both fragments co-existed in one population whereas the longer fragment was dominant in other three populations. The results may reflect ongoing homogenization of satellite DNA type over a short evolutionary time scale.

Animals↗

PubMed2000

Observation of a spin-flip M1 transition in 7(lambda)Li.

Using a large-acceptance germanium detector array (Hyperball), we have observed a spin-flip M1 gamma transition between the ground-state spin doublet of (7)(Lambda)Li (3/2(+)-->1/2(+)). The observed energy of 691.7+/-0.6(stat)+/-1.0(syst) keV provides crucial information on the strength of the spin-spin interaction between a Lambda and a nucleon. This is the first observation of well-identified hypernuclear gamma transitions using germanium detectors.

Journal Article↗

PubMed2000

A novel human HER2-derived peptide homologous to the mouse K(d)-restricted tumor rejection antigen can induce HLA-A24-restricted cytotoxic T lymphocytes in ovarian cancer patients and healthy individuals.

A mouse HER2-derived peptide, HER2p63 (A) (TYLPANASL), can induce K(d)-restricted mouse cytotoxic T lymphocytes (CTL) and also function as a tumor rejection antigen in an in vivo assay. Since the anchor motif of mouse K(d) for peptide binding has much similarity to that of human HLA-A2402, we asked if human HER2p63 (T) (TYLPTNASL) could induce HER2-specific CTL in HLA-A2402-positive individuals. Peripheral blood mononuclear cells (PBMC) of HLA-A2402-positive individuals were sensitized in vitro with HER2p63-pulsed autologous dendritic cells prepared from PBMC. CTL clone derived from these specifically lysed HER2-expressing cell lines bearing HLA-A2402. Cytotoxic activity of the CTL clone against the HER2-expressing cell line bearing HLA-A2402 was blocked by antibodies against CD3, CD8, HLA-A24 or MHC class I, and was also inhibited by the addition of excess HER2p63-pulsed C1R bearing HLA-A2402. Killer cells were generated from PBMC of seven healthy individuals and five ovarian cancer patients, all of HLA-A2402 type, by in vitro sensitization with HER2p63-pulsed autologous antigen presenting cells. These killer cells selectively lysed HER2-expressing SKOV3 transfected with HLA-A2402 cDNA, indicating high immunogenicity of HER2p63 in all 12 individuals examined.

Animals↗

PubMed1993

[Production and inhibition of eosinophil colony stimulating factor by lymphocytes from patients with bronchial asthma].

To clarify the mechanism of the eosinophilia in patients with bronchial asthma (BA), we examined the production and inhibition of eosinophil colony stimulating factor (Eo-CSF) of mononuclear cells (MNC) and lymphocytes from BA. After bone marrow cells from normal volunteers (NA) were incubated with culture media of MNC or lymphocytes cultured in the presence of interleukin-2 (IL-2, 1 U/ml) or Dermatophagoides farinae (10 micrograms/ml, Df), the number of eosinophils was increased and GM-CSF production was increased after 5 days of culture. Interleukin 5 (IL-5) production was increased in some cases of BA, but did not differ between BA and NA delete. When MNC were incubated in the presence of IL-2 and interleukin 4 (IL-4), neither eosinophilia nor GM-CSF production occurred. These results suggest first that MNC and T cells in BA have increased responsiveness to IL-2 and Df, second that increased GM-CSF production partly causes eosinophilia, and third that IL-4 inhibited IL-2-induced eosinophil proliferation by inhibition of GM-CSF production.

Adult↗

PubMed1991

Mechanical stress as a stimulant to the production of osteocalcin in osteoblast-like cells.

When mechanical stress is applied, osteoblasts have shown to produce bone turnover stimulating hormones and enzymes like prostaglandin E2 (PGE2), cyclic AMP, alkaline phosphatase, and collagenase. Osteocalcin (bone Gla protein) is also a protein produced by osteoblasts to control bone metabolism. Thus, its production may also be stimulated by mechanical stress. The purpose of this investigation was to test if mechanical stress stimulates osteoblast-like cells to produce osteocalcin in vitro. The results suggest that osteocalcin production is stimulated at the initial stage of the culture by cyclic tension and relaxation force, and secretion may decrease with time.

Animals↗

PubMed1991

The lactic acid and citric acid content in the gingival fluid of orthodontic patients.

Alveolar bone turnover has two phases: bone resorption and formation. Bone resorption entails both mineral removal and collagenolysis. A pH decrease over the local bone surface is required for mineral removal. Both lactic acid and citric acid has been suggested as the acids which remove crystals. During the orthodontic movement of teeth, a process of overall bone resorption occurs during displacement, whereas at the retention stage this process needs to be stopped in order to stabilize the alveolar bone. Thus, lactic acid and citric acid may be valid parameters of bone resorption intensity. The purpose of this investigation is firstly to test if these acids can be detected in gingival fluid around the moving teeth, and secondly to find if any changes occur before, during and after orthodontic tooth movement. The results indicate that these acids can be good parameters which show how favorably tooth movement is proceeding. They also show how stable the teeth are when orthodontic force is stopped to apply.

Adolescent↗

PubMed1990

Some considerations about maintenance of the mandibular position for adult patient with TMJ disorder.

The patient was twenty-three year old female with TMJ disorder and crowding. She had often had a clicking sound caused probably by malocclusion since she was eighteen years of age. Limitation of mouth opening with TMJ locking has been occurring since she had an impacted right lower third molar extracted at nineteen. A stabilization splint was applied for better mandibular position to rectify the TMJ disorder. The clinical symptom was relieved one month later, so the malocclusion was treated with a multi-bracket appliance. Since cross bite in [formula: see text] was corrected in a year and three months, symptoms of the TMJ disorder disappeared and this condition has remained stable for the past year. A stabilization retainer worn at night was considered necessary to prevent a relapse of the dentition and mandibular position, and to keep the masticatory muscles relaxed. For the purpose of stabilizing the TMJ condition and occlusion, the patient was taught unilateral mastication in order to diminish the difference between sides in chewing force, because only one side had been habitually used for a long time. It is suggested that such an alternative chewing habit will improve functional stability following the structural correction.

Adult↗

PubMed1990

[Treated case with horizontally impacted mandibular first molar caused by submerged primary molar].

A case is here presented in which mandibular first molar was horizontally impacted under the submerged primary molar. The patient was an 8 year-old-boy referred from a general dentist through the Department of Pedodontics in this hospital, whose chief complaint was a horizontally impacted mandibular first molar. Skeletally, diagnosis revealed an Angle Class II Division 2 malocclusion. The impacted first molar was uprighted with a lingual arch and a utility arch following the extraction of the submerged primary molar. The submerged primary molar was probably ankylosed causing a locking of the first molar which rotated as the root formed. The result of rotation during forming twisted the roots of the first molar, which will make root canal treatment difficult if the pulp is infected in the future. It may concluded that dental arches should be carefully observed even in the deciduous dentition.

Ankylosis↗

PubMed1990

[Orthodontic treatment of adults with periodontal disease].

Orthodontic treatment has diversified in recent years along with progress in other dental specialties. Adult orthodontic treatment has become more popular as patients appreciate the need for a higher level of oral health accompanied with progress in orthodontic objectives and treatment methods. At the same time, patients with periodontal disease in number every year. Recently, two adult females with periodontal disease, one with crowding (20 y 1 m at her initial visit) and the other with bimaxillary protrusion (34 y 9 m at her initial visit), obtained good occlusion and periodontal health through orthodontic treatment. As a result of free mandibular movement by applied mild orthodontic forces and balanced occlusion, infrabony defects improved to achieve a higher level of the alveolar crest.

Adult↗

PubMed1989

[Chronic trismus in the severe skeletal Class III cases].

In general, patients who have trismus as chief complaint often have acute symptoms, but limited number of these patients have chronic trismus. We studied 51 patients (mean age; 18y 4n) with severe skeletal class III (less than ANB less than or equal to O), who need surgical treatment. Three types were classified according to the movement of the mandibular head at the maximum mouth opening at their first visit. A-type; the mandibular head hardly move. B-type; it dose not move beyond articular eminence. C-type; it moves beyond articular eminence. These classifications were applied to the both sides of the mandibular head in the 51 patients to divide into 5 types (Type AA, Type AB, Type BB, Type BC, Type CC). Those patients were analyzed according to these five types. The results obtained were as follows; 1) Seventy-three percent of all the cases were female in this study. Sixty-five percent of both the sexes had chronic trismus without having subjective symptoms on the mandibular joints in their daily lives. Type AA, AB, BB, and BC accounted for 12%, 6%, 31%, and 16% respectively. 2) There were fewer contacts in the upper posterior antagonist teeth in AA and AB; particularly at 5. In all the cases of Type CC, contacts with the antagonist tooth 5 were seen. 3) As a conclusion, movement of the mandibular head in the patients with trismus are found to have a characteristic limitation at the maximum mouth opening and the stress points in the occlusal contacts at the centric occlusion to be the posterior area.

Adolescent↗