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Biomedical subjects

Y Harada

Publications and source records attributed to Y Harada.

At least 127 records · Page 7Linked to original sources
PubMed2000

Ultrastructural and functional studies of cryopreserved rat lungs for transplantation using a new hyperosmolal solution.

One of the most promising approaches for extending the period of tissue or organ preservation is to induce a state of cryopreservation. In this report, to achieve successful lung cryopreservation, we created a new hyperosmolal solution (HOS) containing 10% glycerol and 5% dimethyl sulfoxide (Me2SO). We compared the efficacy of HOS with that of Euro-Collins solution (ECS) in rat lung cryopreservation from an ultrastructural and functional point of view. Using ECS, widespread damage to the air-blood barrier was observed even in the lungs cryopreserved at -10 degrees C. At -196 degrees C, the capillary lumen was obstructed with a mesh-like formation derived from deteriorated endothelial cells. In contrast, using HOS, the cryopreserved lungs at -10 degrees C were characterized by well preserved endothelial cells and basal laminae, despite the existence of focal cytoplasmic swelling of epithelial cells. The endothelial cells and basal laminae were successfully preserved up to -196 degrees C. Considering the survival rates at day 7 after cryopreserved lung transplantation, the grafted left lungs functioned normally only when perfused by and preserved in HOS at -10 degrees C. These findings demonstrate that HOS was effective not only for endothelial cells and basal laminae up to -196 degrees C, but also lung cryopreservation at least up to -10 degrees C.

Animals↗
PubMed2000

Myelodysplastic syndrome terminating in erythropoietic protoporphyria after 15 years of aplastic anemia.

The authors report a case of aplastic anemia in which refractory anemia, a subtype of myelodysplastic syndrome (MDS), developed 15 years after the onset and was subsequently followed by erythropoietic protoporphyria (EPP). Defects of stem cells in MDS are thought to be responsible for the disturbance of the heme biosynthetic pathway, leading to the development of EPP.

Anemia, Aplastic↗
PubMed2000

Comparison of intratumoral distribution of 99mTc-MIBI and deoxyglucose in mouse breast cancer models.

UNLABELLED: The aims of this study were to evaluate the distribution of 99mTc-methoxyisobutylisonitrile (MIBI) in 3 animal models of breast cancer, the effect of radiotherapy on 99mTc-MIBI uptake, and the relationship between uptake and microvessel density. METHODS: We used syngeneic, subcutaneously transplanted FM3A, MM48, and Ehrlich mouse breast cancer. 99mTc-MIBI and FDG were injected intravenously, and tumor uptake was measured 30 min later. Double-tracer macroautoradiography (ARG) images were prepared with 99mTc-MIBI and 2-deoxy-D-[1-14C]-glucose (14C-DG), analyzed quantitatively, and compared with histology. The radiotherapeutic effects of 20 Gy x-ray irradiation were monitored by measuring tumor volume, tumor uptake, and ARG findings using 99mTc-MIBI and FDG in FM3A tumors. Microvessel density was quantified by immunohistochemical staining for CD34 and compared with ARG using 99mTc-MIBI in FM3A tumors. RESULTS: FM3A, MM48, and Ehrlich tumors showed different growth rates and radiosensitivities. Uptake of FDG, but not of 99mTc-MIBI, correlated significantly with growth rates. Compared with 14C-DG, 99mTc-MIBI accumulated more in cancer cells and less in infiltrating fibroblasts and macrophages in all tumor models. Irradiation significantly decreased 99mTc-MIBI uptake, but a rapid increase was noted at recurrence on day 7. Changes in FDG uptake were not significant at recurrence. Microvessel density in tumor tissue correlated significantly with 99mTc-MIBI uptake on ARG. CONCLUSION: Accumulation of 99mTC-MIBI in cancer cells is preferential and can be used as a sensitive marker to examine the response to radiotherapy. Angiogenesis seems to enhance accumulation of 99mTc-MIBI in tumors. These characteristics may be favorable for tumor imaging using 99mTC-MIBI.

Animals↗
PubMed2000

Necessity of correcting cancer antigen 125 appearance rates by body surface area.

Attention has been focused on cancer antigen 125 (CA125) levels in dialysate as an index for evaluating the severity of peritoneal mesothelial cell impairment. However, the method of evaluating CA125 levels in the dialysate has not been standardized. We determined that CA125 levels in the dialysate should be corrected by body surface area (BSA). Using 51 patients who had been undergoing peritoneal dialysis (PD), CA125 levels in the dialysate were measured to evaluate the appearance rate of CA125 (CA125AR). Because only 18 of the 51 patients (35%) had a BSA greater than 1.73 m2, CA125 levels in the dialysate might be underestimated in other patients when absolute values of CA125 are not corrected by BSA. When correlations between corrected CA125AR and various parameters were evaluated, corrected CA125AR positively correlated with age, but negatively correlated with serum creatinine and albumin levels. Moreover, no positive correlation was seen between corrected CA125AR and the duration of PD or the peritoneal permeability test. However, in 5 patients with ultrafiltration loss after prolonged PD, the values of CA125AR persistently or rapidly decreased before transfer to hemodialysis. Although CA125 can be used as an index of peritoneal deterioration, the absolute value of CA125 should be corrected by BSA. However, it is most important to evaluate changes in CA125 in individual patients.

Adult↗
PubMed2000

Surgical treatment for sclerosing encapsulating peritonitis.

Sclerosing encapsulating peritonitis (SEP) is recognized as a serious complication of continuous ambulatory peritoneal dialysis (CAPD). To date, in our hospital, 12 cases of SEP have been successfully treated by active intervention. The development of SEP was observed in these patients after removal of a peritoneal catheter. SEP was relieved by steroid administration in 3 of these patients, and by total parenteral nutrition (TPN) performed after exploratory laparotomy in 1 patient. In the remaining 8 patients, SEP was relieved by total intestinal enterolysis. In patients who underwent total intestinal enterolysis, the severity of encapsulation and adhesion varied. White, rigid encapsulation was observed in 4 patients who had been treated by peritoneal dialysis (PD) for less than 10 years. Seemingly normal serosae were observed under the capsules, and total intestinal enterolysis was easily performed in these patients. In the patient who underwent renal transplantation, more severe intestinal adhesion was observed, although the duration of PD was limited to 70 months and the intestinal serosae were seemingly normal. These findings were considered specific to SEP developing after immunosuppressant administration. In 3 patients who had undergone PD for more than 10 years, degeneration of the visceral peritoneum was observed, together with an ill-defined boundary between the capsules and the serosae. Therefore, total enterolysis was performed in these patients, including a wide area of the muscular layer. Furthermore, calcification was observed in several regions, where the capsules were severely adherent to the parietal peritoneum. The post-operative course for all 8 patients was satisfactory, and these patients finally returned to their previous social activities. We conclude that when SEP symptoms are not improved by steroid administration or TPN, active total intestinal enterolysis should be performed. However, it is absolutely important to avoid inducing anastomosis or impairing the intestine.

Adult↗
PubMed2000

[A successful case of post operative management using nitrogen gas inhalation for a one-month old infant with high pulmonary blood flow].

We report a successful case of post operative management by inhaling nitrogen gas for a one-month old infant with high pulmonary blood flow after Blalock-Taussig shunt and plasty of the pulmonary artery. The operation was performed under extracorporial circulation. Nitrogen gas inhalation was dramatically effective for this infant to stabilize his post operative hemodynamic state. This therapy appears to be a very useful and easy handling technique in postoperative management for a patient with high pulmonary blood flow.

Abnormalities, Multiple↗
PubMed2000

[Comparison of chest CT findings between suspected and definite cases of primary pulmonary M. avium complex infection].

It is very difficult to treat pulmonary infection with MAC, because we have few effective drugs against this organism. In this situation, an early diagnosis and treatment are very important to manage this disease. We evaluated chest CT scans of the primary pulmonary MAC infection which had no underlying lung diseases and no immunocompromised diseases such as HIV infection. We defined suspected cases of pulmonary MAC infection as cases in which abnormal features of chest CT scans were recognized but frequency of detection of organisms of MAC did not fulfil the diagnostic criteria for atypical mycobacteriosis according to Japanese Mycobacteriosis Research Group of the National Chest Hospitals. CT scans of suspected cases were compared with the definite cases. Results obtained were as follows: 1. In classification by CT scans of primary pulmonary MAC infection, the proportion of localized type and diffuse type was the same both in suspected and definite cases. In localized type, more tuberculosis-like pattern was seen in definite cases. 2. In suspected cases, characteristic features of CT scans of primary pulmonary MAC infection were recognized in the same frequency as in definite cases. 3. In pulmonary tuberculosis-like type, definite cases showed more cavitary lesions than suspected cases. These results showed that a careful long term follow-up of suspected cases with frequent bacteriological tests of sputum and chest CT scannings was important for early diagnosis of primary pulmonary MAC infection.

Aged↗
PubMed2000

[Clinical training and home therapy in our clinic].

Since 1986, we have practiced clinical training. In this training, the physician trainee acts as the head of our clinic, managing programs including the medical teams for outpatient clinics and home therapy. Our home therapy started in 1975 and successive resident trainees have held conferences, cooperation between hospitals and clinics between clinics, and also held home patient and family parties. In our clinical training, therefore, the resident can effectively gain generalized clinical abilities.

Aged↗
PubMed1999

Cyclic AMP inhibits the activity of c-Jun N-terminal kinase (JNKp46) but not JNKp55 and ERK2 in human helper T lymphocytes.

The cyclic AMP (cAMP) elevating agent PGE(2) and dibutyryl cyclic AMP (dBcAMP) affect T cell functions. Using human helper T cell clones, we examined effects of cAMP on c-Jun N-terminal kinase (JNK) and extracellular signal-regulated kinase (ERK), which are assumed to play a role in T cell regulation. When we analyzed the effects of dBcAMP on activities of mitogen-activated protein kinase (MAPK) family members ERK2, JNKp55 and JNKp46, dBcAMP did not inhibit the activities of ERK2 and JNKp55 induced by PMA/A23187 stimulation. JNKp46 activity was, however, inhibited by dBcAMP. JNK phosphorylates c-Jun on Ser-63 and Ser-73, the result being induction of its transcriptional activity. We found that dBcAMP inhibited the phosphorylation of c-Jun Ser-63 induced by PMA/A23187 stimulation. We suggest a different mechanism of regulation of JNKp55 and JNKp46 activities and that JNKp46 is a specific c-Jun kinase by which the activity of c-Jun is regulated in T lymphocytes.

Antibodies↗
PubMed1999

Short- vs. long-range disperser: the evolutionarily stable allocation in a lattice-structured habitat

The population dynamics of two types of organisms in a lattice-structured habitat are studied and the evolutionarily stable allocation between short- and long-range disperser is calculated. Offsprings of short-range dispersal stay in the vicinity of their parent and cause local competition. Using pair approximation, I derive a closed system of ordinary differential equations of global and local densities (or mean crowding), and calculate the condition for one type to invade the population dominated by the other type. The evolutionarily stable strategy (ESS) of resource allocation is derived for the case in which there is a linear trade-off between short- and long-range dispersers. The maximum equilibrium abundance of the population may be achieved by a mixture of both types of dispersers, but it is in general different from the ESS resource allocation calculated from the invasibility condition. For the same parameter values, the ESS invests a larger fraction of resources to short-range disperser than the optimal allocation which maximizes the equilibrium population density. This difference can be explained by the fact that long-range disperser is more effective in the preoccupation of space than short-range disperser. The predictions are confirmed by the direct computer simulations of the lattice stochastic models. Copyright 1999 Academic Press.

Journal Article↗
PubMed1999

Turnover of the aggregates and cross-linked products of the D1 protein generated by acceptor-side photoinhibition of photosystem II.

It is known that the reaction-center binding protein D1 in photosystem (PS) II is degraded significantly during photoinhibition. The D1 protein also cross-links covalently or aggregates non-covalently with the nearby polypeptides in PS II complexes by illumination. In the present study, we detected the adducts between the D1 protein and the other reaction-center binding protein D2 (D1/D2), the alpha-subunit of cyt b(559) (D1/cyt b(559)), and the antenna chlorophyll-binding protein CP43 (D1/CP43) by SDS/urea-polyacrylamide gel electrophoresis and Western blotting with specific antibodies. The adducts were observed by weak and strong illumination (light intensity: 50-5000 microE m(-2) s(-1)) of PS II membranes, thylakoids and intact chloroplasts from spinach, under aerobic conditions. These results indicate that the cross-linking or aggregation of the D1 protein is a general phenomenon which occurs in vivo as well as in vitro with photodamaged D1 proteins. We found that the formation of the D1/D2, D1/cyt b(559) and D1/CP43 adducts is differently dependent on the light intensity; the D1/D2 heterodimers and D1/cyt b(559) were formed even by illumination with weak light, whereas generation of the D1/CP43 aggregates required strong illumination. We also detected that these D1 adducts were efficiently removed by the addition of stromal components, which may contain proteases, molecular chaperones and the associated proteins. By two-dimensional SDS/urea-polyacrylamide gel electrophoresis, we found that several stromal proteins, including a 15-kDa protein are effective in removing the D1/CP43 aggregates, and that their activity is resistant to SDS.

Chlorophyll↗
PubMed1999

Structure-activity relationship of gramine derivatives in Ca(2+) release from sarcoplasmic reticulum.

5,6-Dibromo-1,2-dimethylgramine evoked Ca(2+) release from skeletal muscle sarcoplasmic reticulum through ryanodine receptors in a concentration-dependent manner with an EC(50) of 22.2 microM. Since the EC(50) of caffeine was 0.885 mM, 5,6-dibromo-1,2-dimethylgramine was 40 times more sensitive than caffeine. Among 14 gramine derivatives having different substituents at N-1, C-2, C-5 or C-6 of the indole skeleton, we found that five derivatives were effective. Study of the structure-activity relationship for Ca(2+) release indicated that 1-methylation and/or both 5- and 6-bromination are important for Ca(2+) release. Thus, gramine derivatives are useful tools for the investigation of Ca(2+) release from sarcoplasmic reticulum.

Alkaloids↗
PubMed1999

Recovery from exercise-induced desaturation in the paraspinal muscles in idiopathic scoliosis.

STUDY DESIGN: A study using near-infrared light spectroscopy to measure recovery from exercise-induced desaturation in the paraspinal muscles of patients with idiopathic scoliosis. OBJECTIVES: To measure oxygenation of the paraspinal muscles and obtain differences between the convex and concave sides. SUMMARY OF BACKGROUND DATA: Authors of previous studies have reported that some patients experience pain on the convex side of the paraspinal muscles. The muscles on the convex side are more stretched and stressed than those on the concave side. The current authors investigated the degree of stress by measuring oxygenation and blood volume changes. METHODS: Paraspinal muscle spectral properties at L3 were investigated using near-infrared light spectroscopy. Thirty-six patients (8 men and 28 women) underwent this procedure. To assess a level of peripheral adaptations to exercise, the half-time of Oxyhemoglobin/Myoglobin recovery was measured, which indicates the recovery from energy deficit after exercise. RESULTS: The average half-time recovery on the convex side was 3.38 seconds (range, 1.5-5.5 seconds), whereas that on the concave side was 1.51 seconds (range, 0.7-4.0 seconds). The average difference between the convex side and the concave side was 1.87 seconds (range, 0.9-3.5 seconds). CONCLUSIONS: Half-time recovery on the convex side in the patients with idiopathic scoliosis was slower than that in healthy adults (P < 0.05). Half-time recovery on the concave side in such patients was faster than that on the convex side (P < 0.01). The authors consider half-time recovery an indication of back muscle stress.

Adult↗
PubMed1999

Tying a molecular knot with optical tweezers.

Filamentous structures are abundant in cells. Relatively rigid filaments, such as microtubules and actin, serve as intracellular scaffolds that support movement and force, and their mechanical properties are crucial to their function in the cell. Some aspects of the behaviour of DNA, meanwhile, depend critically on its flexibility-for example, DNA-binding proteins can induce sharp bends in the helix. The mechanical characterization of such filaments has generally been conducted without controlling the filament shape, by the observation of thermal motions or of the response to external forces or flows. Controlled buckling of a microtubule has been reported, but the analysis of the buckled shape was complicated. Here we report the continuous control of the radius of curvature of a molecular strand by tying a knot in it, using optical tweezers to manipulate the strand's ends. We find that actin filaments break at the knot when the knot diameter falls below 0.4 microm. The pulling force at breakage is around 1 pN, two orders of magnitude smaller than the tensile stress of a straight filament. The flexural rigidity of the filament remained unchanged down to this diameter. We have also knotted a single DNA molecule, opening up the possibility of studying curvature-dependent interactions with associated proteins. We find that the knotted DNA is stronger than actin.

Actins↗
PubMed1999

Expression pattern of Brachyury and Not in the sea urchin: comparative implications for the origins of mesoderm in the basal deuterostomes.

This work concerns the expression of two transcription factors during the development of the sea urchin Strongylocentrotus purpuratus: SpNot, the orthologue of the vertebrate Not gene, and SpBra, the orthologue of the vertebrate Brachyury gene. SpNot transcripts are detected by in situ hybridization in the vegetal plate at the mesenchyme-blastula stage. Later the gene is expressed in the secondary mesenchyme, but expression is no longer detectable after gastrulation. SpNot is upregulated during larval development, in the invaginating vestibule of the adult rudiment. Transcripts are also found in several larva-specific tissues, including the epaulets, blastocoelar cells, and pigment cells. SpBra also displays a discontinuous pattern of expression. Much like SpNot, this gene is expressed during embryogenesis in the embryonic vegetal plate and secondary mesenchyme founder cells, and expression is then extinguished. The gene is upregulated over a week later in the feeding larva, in the vestibule of the adult rudiment. In contrast to SpNot, SpBra is also expressed in the mesoderm of both left and right hydrocoels, and it is not expressed in any larva-specific tissues. We compare the spatial expression profile determined in this study with that of the orthologous Brachyury gene in an indirectly developing enteropneust hemichordate, a representative of the sister group to the echinoderms within the deuterostomes. These observations illuminate the genetic basis underlying the process of maximal indirect development in basal deuterostomes. Finally, Brachyury appears to be an excellent marker for the progeny of the set-aside cells of the sea urchin embryo.

Amino Acid Sequence↗
PubMed1999

Feasibility of using the automatic generating system for quartz watches as a leadless pacemaker power source.

An automatic power-generating system (AGS) which converts kinetic energy into electric energy for quartz watches was tested as a power source for implantable cardiac pacemakers. An automatic power-generating mechanism and a capacitor (0.33 F) were removed from a quartz watch (SEIKO) and encapsulated in a polyvinyl case. Characteristics of the AGS were investigated by acceleration equipment. The capacitor in the AGS was charged to 2.0 V (0.66 J) by placing it on the equipment for about 30 minutes. The equipment has a 2 Hz cycle and generates +/- 1.7 G at the end of each half cycle. The AGS (fully charged to 2.0 V) was used as the power source for a pulse generator circuit built using commercially available CMOS IC. The circuit generated pulses of 0.5 ms width at 1 Hz (60 pulses min-1). The voltage of the AGS was maintained at 1.6 V while it was being charged by the accelerations. The generator supplied pulses of 0.75 V, 1.47 mA through a 510 omega load. With fully charged AGS, the generator was also used to pace a mongrel dog's heart at 140 beats min-1 for 60 minutes. During pacing, the AGS supplied 420 mJ to the circuit and the cardiac muscle. The AGS was placed on the right ventricular wall of the mongrel dog under anaesthesia. Energy of 80 mJ is stored in a capacitor by the heart beating at about 200 beats/min for 30 minutes. Thus the AGS generated 13 microJ per heart beat. This result suggests that the AGS may supply enough energy for use in a cardiac pacemaker.

Electric Power Supplies↗
PubMed1999

Parenchymal cells proliferate and differentiate in an organotypic slice culture of the neonatal liver.

We applied organotypic slice culture of neonatal mouse liver tissues to maintain the parenchymal cells in ontogenesis and to investigate their proliferation and differentiation. Cultured tissue spread gradually over 3 weeks. Small basophilic cells formed several layers in the center of the cultured tissues, and a monolayer of polygonal cells was seen at the periphery. Albumin- and alpha-fetoprotein-immunoreactions were seen in polygonal cells, as were proliferating cell nuclear antigen-immunoreactions. Connexin 32- and 26-immunoreactions were observed in small plaques on the membrane of the polygonal cells, and electron microscopy showed gap junctional complexes. Ultrastructurally, polygonal cells had a round nucleus and abundant cytoplasmic organelles, and bile canaliculi were seen on the cytoplasmic membrane. Cytokeratin 19-immunoreactions were scattered in clusters. There were ultrastructurally bile-duct-like structures with microvilli on the inner surface of the cavity and tight junctions between their constituent cells. Quantitative analysis of albumin-, alpha-fetoprotein- and cytokeratin 19- or proliferating cell nuclear antigen-immunoreactivity in parenchymal cells showed changes of their phenotypes or maintenance of their proliferation in tissue culture. Our slice-culture system enabled us to maintain and to develop parenchymal cells in the liver tissue for at least 3 weeks. The findings suggest that organotypic slice culture applied to liver tissues in ontogenesis may be a useful tool not only to maintain parenchymal cells but also to investigate their proliferation and differentiation.

Albumins↗