Biomedical subjects

H Itagaki

Publications and source records attributed to H Itagaki.

At least 19 recordsLinked to original sources

PubMed2000

New technique for producing hybridoma by using laser radiation.

BACKGROUND AND OBJECTIVE: With conventional methods, cell fusion rate is extremely low, and fusion of two specific cells is not possible. We developed a new method for inducing cell fusion under the microscope by using a microprocessing device by laser. STUDY DESIGN/MATERIALS AND METHODS: Under a microscope, the target cells were irradiated with laser beams for trapping. Then, the trapped cells were transferred and placed in contact with the corresponding cells, which were also fixed by laser beam. The pulse laser beams are focused on the contact surface to cut small perforations for mutual communication of the cytoplasms. RESULTS: The fusion rate of mouse myeloma cells was 38%. The rate of hybridoma production of myeloma cell and lymphocyte was 2%. We confirmed the proliferation of the newly formed hybridoma in HAT medium and the production of immunoglobulin G. CONCLUSION: This new cell fusion method is characterized by production of hybridomas of target cells, lower cell toxicity, and a high rate of hybrid production.

Animals↗

PubMed2000

Sarcocystis sp. from cattle slaughtered in Japan.

Sarcocystis sp. was detected from cattle slaughtered in Saitama Prefecture, Japan. The cysts were 3,400-4,400 x 198-238 microm in size and had the thick cyst wall which was 7 to 10 microm thick and provided with finger-like villar protrusions. The protrusions were 8-9.5 x 2-2.5 microm in size and had microtubules in the core.

Abattoirs↗

PubMed1999

Peripheral and central structures involved in insect gustation.

Studies in insect gustation have a long history in general physiology, particularly with work on fly labellar and tarsal sensilla and in the general field of insect-plant interactions, where work on immature Lepidoptera and chrysomelid beetles has been prominent. Much more emphasis has been placed on the physiological characteristics of the sensory cells than on the central cellular mechanisms of taste processing. This is due to the fairly direct access for physiological experimentation presented by many taste sensilla and to the obvious importance of tastants in insect feeding and oviposition behaviour. In some of the insect models used for gustatory studies, advances have been made in understanding the basic morphology of the central neuropils involved in the first stages of taste processing. There is much less known about the physiology of interneurons involved. In this review, we concentrate on four insect models (Manduca sexta, Drosophila melanogaster, Neobellieria bullata (and other large flies), and Apis mellifera) to summarize morphological knowledge of peripheral and central aspects of insect gustation. Our views of current interpretations of available data are discussed and some important areas for future research are highlighted.

Animals↗

PubMed1999

Induction of tumor necrosis factor alpha and nitric oxide in rabbits inoculated with a cyst extract of Sarcocystis cruzi.

Rabbits develop a toxic reaction similar to endotoxemia following inoculation with a Sarcocystis cruzi cyst extract. To analyze the pathophysiology of the reaction, serum tumor necrosis factor alpha (TNFalpha), nitric oxide (NO) and lipid-lipoprotein profiles were investigated in rabbits given the cyst extract and lipopolysaccharide (LPS) by subcutaneous inoculation. In animals given the cyst extract, overproduction of TNFalpha was detected, together with an increase in NO. The animals developed derangement of lipid metabolism, which was considered to have resulted from TNFalpha induction, consisting of elevated triglyceride and very low density lipoprotein levels and decreased high density lipoprotein (HDL) levels. Serum interleukin-6-like activity also increased transiently in the animals. Capability of the cyst extract to induce TNFalpha, NO and the lipid profile derangement were completely lost by boiling. In animals given LPS, TNFalpha was induced and HDL decreased moderately, without inactivation of those activities of LPS by boiling. These results indicated that S. cruzi cyst extract is a potent, but thermolabile inducer of TNFalpha and NO for rabbits. It is likely that TNFalpha and NO play important roles as mediators in the reaction associated with toxicity of the cyst extract in rabbits.

Animals↗

PubMed1999

Rapid ex vivo expansion of human umbilical cord hematopoietic progenitors using a novel culture system.

Cell numbers limit the widespread clinical use of cord blood (CB) for gene therapy and marrow replacement in adults; a simple and effective method for ex vivo expansion of CB primitive progenitor cells (PPC) is required. Recently, the combination of thrombopoietin (TPO) and Flk-2/Flt-3 ligand (FL-2) was reported to support slow proliferation of CB-PPC in stroma-free liquid culture. We established a novel culture system in which the murine stromal cell line HESS-5 dramatically supports the rapid expansion of cryopreserved CB-PPC in synergy with TPO/FL-2. Furthermore, while HESS-5 cells directly adhered to human progenitors during culture, the cultured human cells could easily be harvested without contamination by HESS-5 cells. Within 7 days of culture, a 100-fold increase in CD34bright/CD38dim cells was obtained in serum-containing culture. When HESS-5 cells were physically separated from human progenitor cells in the presence of TPO/FL-2, synergy was blocked, suggesting that HESS-5 cells support proliferation of PPC by direct cell-to-cell interaction. The hematopoietic-supportive effects of this xenogeneic coculture system were then assessed in a very short-term (5 days) serum-free culture. Expansion was further enhanced by addition of stem cell factor (SCF) or interleukin-3 (IL-3). As a result, a 50- to 100-fold increase in CD34bright/CD38dim cells was noted. Colony-forming units in culture (CFU-C) and mixed colonies (CFU-GEMM) were enhanced by 10- to 30-fold and 10- to 20-fold, respectively. Moreover, generation of long-term-culture-initiating cells (LTC-IC) from CD34bright/CD38dim cells was amplified by 25-fold. The severe-combined immunodeficient (SCID) mouse-repopulating cell (SRC) assay confirmed extensive ability of the expanded cells to reconstitute long-term hematopoiesis. These results indicate that this xenogeneic coculture system, in combination with human cytokines, can rapidly generate PPC from cryopreserved CB.

Animals↗

PubMed1999

First isolation of Sarcocystis hominis from cattle in Japan.

Sarcocystis hominis was first isolated from slaughtered cattle raised in Japan. Cysts were 1,220-4,460 x 80-384 microns in size and their wall was 3 to 6 microns thick and appeared radially striated in the histopathological sections because of the presence of palisade-like villar protrusions on the surface. The protrusions were 3.1-4.3 x 0.7-1.1 microns in size and had many microtubules in the core. Two cynomolgus monkeys, Macaca fascicularis, fed with the Sarcocystis cysts began to pass sporocysts, which measured a size of 14.3-15 x 9.5-10 microns, in the feces 10 days after ingestion.

Animals↗

PubMed1998

Soil factors influencing the distribution of Oncomelania quadrasi, the intermediate host of Schistosoma japonicum, on Bohol Island, Philippines.

Soil conditions essential to the survival of Oncomelania quadrasi on Bohol Island in the Philippines were examined to clarify the factors limiting distribution of the snail and to develop a method for breeding large numbers of the snail in the laboratory. Soil samples in and around snail habitats were analysed and used for breeding experiments in the laboratory. Experiments using paddy soil derived from different parent materials revealed that the numbers of juvenile snails hatched varied widely between several soil samples. The best soils for reproduction generally had a pH of 5.6-7.9 and > 200 mg of available CaO/100 g. These soil factors, in addition to shade and moisture, determine the optimum conditions for the breeding of O. quadrasi in the field as well as in the laboratory. The determination of the optimum conditions for laboratory breeding of O. quadrasi and other intermediate snail hosts should facilitate detailed study of the hosts and the development of better methods to control or eradicate schistosomiasis and other snail-transmitted diseases.

Animals↗

PubMed1998

Sarcocystis suihominis detected for the first time from pigs in Japan.

Sarcoystis suihominis was detected for the first time in Japan from the heart and diaphragm of 5 out 600 older culled breeding pigs slaughtered in Saitama Prefecture, Japan. Fresh cysts were 1,080-2,040 x 106-170 microns in size. Bradysoites measured 15 x 4 microns on average. The cyst wall was usually observed thick, 4-6 microns, and striated, but occasionally thin and smooth according to the difference in sectioning angle and in portion of cysts. Scanning electron microscopy showed that many palisade-like villar protrusions, 6-6 x 0.3-0.5 microns in size, were closely folded onto the surface of cyst. A small number of microtubules were seen in the core of protrusion. No dogs nor domestic cats fed with 20 fresh cysts each excreted oocysts or sporocysts in the feces throughout the experimental period of 30 days.

Animals↗

PubMed1997

Sarcocystis mihoensis n. sp. from sheep in Japan.

Sarcocystis mihoensis n. sp., a heteroxenous coccidium was detected from sheep in Japan and dogs were experimentally determined as the definitive host. The cysts were 1,300-2,100 x 200-300 microns in size and had the thick cyst wall which was 10 to 12 microns thick and provided with radial striated and finger-like villar protrusions. Two 6-month old dogs fed with the cysts passed sporocysts, 15-16 x 8-9 microns in size, in the feces from day 11 to days 57-60 after ingestion. No domestic cats fed with same cysts shed sporocysts throughout the experimental period.

Animals↗

PubMed1997

[Functional MRI using interleaved EPI].

One of main purposes of functional MRI is to identify functional map on human brain. We considered spatial resolution was a important factor and investigated influences of it on signal changes and activated region size. Functional images were acquired with Echo-Planar imaging (EPI) and interleaved EPI (IEPI). IEPI is superior in spatial resolution but inferior in signal to noise ratio (SNR) to EPI. As a result of Student's t-test analysis, activated region sizes of IEPI reduced to less than half those of EPI while IEPI had larger signal increase than EPI. We confirmed that the reduction was caused by low SNR and our estimation analysis could prevent it.

Brain↗

PubMed1997

[Somatotopical mapping of the human somatosensory cortex with echo-planar MRI].

The somatotopical organization of the somatosensory cortex was analyzed. Echo-planar imaging was used to obtain functional images, and magnetic field strength was 1.5T. Natural stimulation at a frequency of 3 Hz (scrubbing or tapping) was applied to one of the three cutaneous areas: toes, fingertips, and tongue tip. The focal bands which show the significant signal increases were located on the contralateral post-central gyrus, and these changes of signal intensity originate from the cortical parenchyma because there were no major veins in the central sulcus. The focal bands which respond to each stimulation sites were anatomically distinct and located medially-to-laterally in the order of toes, fingertips, and tongue tip.

Adult↗

PubMed1997

[Development of new cell fusion technique by laser device and application to bio-medical field].

We developed a new cell fusion method which was sterile, noncontact, and selective technique under the microscope, using the micro-processing device by LASER. By this technique, we succeeded in fusing myeloma cell (SP2) and lymphocyte in mouse. We also defined the proliferation of the fused cells in HAT medium and the function of the fused cells in the Ouchterlony method, i.e. production of IgG. This method enable us to make hybridomas from very small number of cells and to fuse target cells selectively. This method is applicable to fuse cells which are difficult to be fused by conventional methods.

Animals↗

PubMed1996

Transient brain activity used in magnetic resonance imaging to detect functional areas.

Functional areas were detected with short stimuli eliciting transient brain activity using the method of 'transient' regions of interest (ROIs) and functional magnetic resonance imaging (fMRI). This method was validated by comparing the results with sustainedly activated areas identified conventionally. Eighty-eight and 89% of the total areas of transient ROIs derived from 0.2 and 2 s stimulation, respectively, were identified at 5-7 s and 5-9 s, respectively, after stimulus onset. Eighty-eight and 76%, respectively, of these areas overlapped 'conventional' ROIs derived from 20 s stimulation. These results suggest that the delineation of transient ROIs, by targeting a period approximately 7 s after transient neural activity, can be useful for fMRI studies of cognitive functions.

Adult↗

PubMed1996

Ultrastructure of the cyst wall of Sarcocystis species with canine final host in Japan.

The ultrastructural characteristics of cyst wall are a useful clue to the identification of Sarcocystis species. Among the eight species examined, S. cruzi, S. sp. 1 from sheep and S. hircicanis had the thin cyst wall with long, tapered hair-like villar protrusions. The protrusions arose from the dome-like bulges of cyst wall and ran parallel to the surface. No clear ramification was observed in the tip of protrusion of these three species. S. tenella, S. capracanis, S. miescheriana, S. fayeri, and S. sp. 2 from Japanese deer had the thick cyst wall. The villar protrusions of the former three species were palisade-like in shape, but those of S. tenella and S. Capracanis were slightly thinner than those of S. miescheriana. The villar protrusions of S. fayeri and S. sp. 2 were finger-like, but those of the former species were shorter and thicker than those of the latter species. S. fayeri had many minute depressions on the surface of protrusion in a reticular pattern. Microtubules in the core of protrusion were seen in S. miescheriana, S. fayeri and S. sp. 2 but not in the other species. Microdepressions were observed on the surface of cyst wall among the protrusions in all the Sarcocystis species examined, but their function was not made clear.

Animals↗

PubMed1995

Functional mapping of the human somatosensory cortex with echo-planar MRI.

The somatotopical organization of the human somatosensory cortex was analyzed with echo-planar imaging at 1.5 Tesla, utilizing deoxyhemoglobin as an endogenous contrast medium. Scrubbing stimulation at a frequency of 3 Hz was applied to one of three cutaneous areas: toes, fingertips, and tongue tip. Parasagittal echo-planar slices were obtained every 2 s. We found focal bands of increased signal intensity (4% on average) during the stimulation, with a rise time of 2-6 s. These activated bands were located on the contralateral postcentral gyrus. The cortical responses from the three stimulation sites were anatomically distinct and organized medially-to-laterally in the order of toes, fingertips, and tongue tip.

Adult↗

PubMed1995

Hemoglobin denaturation caused by surfactants.

The properties of hemoglobin denaturation caused by two anionic surfactants (sodium dodecylsulfate and sodium lauroylmethyltaurate) were examined using spectrophotometry (multi-plate reader), circular dichroism (CD) and high-performance liquid chromatography (HPLC), and their denaturating action on hemoglobin and sorption to it were examined by various methods. Correlation and factorial analyses were applied to the experimental data and the following results were obtained: (1) High correlations were found among sorption, denaturation and alpha-helix content and the random structure of hemoglobin. (2) The alpha-helix of hemoglobin is randomized as the surfactants denature hemoglobin. (3) Factorial analysis indicates that there are two factors involved in hemoglobin denaturation, one related to the destruction of the alpha-helix and the other related to a change in the beta-structure. These two factors are related to change in the environment around the heme group. (4) Destruction of the alpha-helix seems to be one of the causes of the eye irritation produced by anionic surfactants.

Chromatography, High Pressure Liquid↗

PubMed1995

Toxicity and properties of the extract from Sarcocystis cruzi cysts.

The extract from Sarcocystis cruzi cysts in bovine muscle was subcutaneously injected to mice, guinea pigs, chickens, and rabbits to detect its toxicity. Only rabbits showed reactions after administration of the extract at a dose of 25 micrograms. The main clinical signs of the rabbits were depression, reduction in body temperature and intermittent diarrhea and the hematological findings observed were elevation in WBC, RBC, PCV, TP, BUN, AST, AUT and creatinine values and reduction in glucose, K+ and pH of blood. The extract, crude toxin, was a water soluble, acid-alkali stable and thermolabile protein and estimated to be a molecular mass of 15-16 kd.

Animals↗

PubMed1995

Analysis of Fasciola sp. antigen by enzyme-linked immunotransfer blot using sera from experimentally and naturally infected cattle.

Soluble polypeptides extracted from adult Fasciola sp. were analysed by SDS-PAGE, and their antigenicity was characterized by enzyme-linked immunotransfer blot (EITB) using sera from experimentally and naturally infected cattle. Polypeptides of adult Fasciola sp. with estimated molecular mass of 64-52 kDa, 38-28 kDa, 17 kDa, 15 kDa, 13 kDa and 12 kDa, were recognized by sera obtained in both early and late stages of infection. Furthermore, two polypeptides of more than 160 kDa were detected by sera only in the early stage of infection. The results of EITB using sera of dairy cows naturally infected with Fasciola sp. suggest that polypeptides of 64-52 kDa may be candidates as serodiagnostic antigen of bovine fascioliasis.

Animals↗