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Biomedical subjects

H Hoshi

Publications and source records attributed to H Hoshi.

At least 91 records · Page 5Linked to original sources
PubMed1998

Inhibitory effect of Multiglycosidorum tripterygii on coronary arteriosclerosis after heart transplantation.

BACKGROUND: Graft coronary arteriosclerosis (GCA) is the major limiting factor for long-term survival after heart transplantation. In this study, we investigated the effect of Multiglycosidorum tripterygii (MT) on GCA and platelet-derived growth factor A (PDGF-A) mRNA expression of transplanted hearts. METHODS: Two groups of Lewis rats (n=7/group) underwent heterotopic heart transplantation from Wistar-King donors and were treated with either cyclosporine (CsA;10 mg/kg/day) or MT (30 mg/kg/ day). Histological evaluations of rejection and coronary arteriosclerosis, as well as Northern blot analysis on graft PDGF-A mRNA expression were made 60 days after transplantation. RESULTS: Morphometric results indicated no significant difference in rejection between the CsA- and MT-treated groups. However, the extent of GCA in the MT-treated group was significantly less than that seen in the CsA-treated group (P<0.01). The expression of PDGF-A mRNA of cardiac allograft was also significantly suppressed in the MT-treated group when compared with the CsA-treated group (P<0.01). CONCLUSION: MT is superior to CsA in preventing graft coronary arteriosclerosis, and this efficacy is probably associated with the depressed expression of graft PDGF-A mRNA in the MT-treated group.

Animals↗
PubMed1998

Effectiveness of ischemic preconditioning on long-term myocardial preservation.

BACKGROUND: This study was designed to assess whether the protective effect of ischemic preconditioning can be adapted for myocardium undergoing 6 hr of ischemia. METHODS: Eighteen isolated rat hearts were perfused with oxygen-bicarbonated Krebs-Henseleit buffer in the Langendorff mode for 35 min (group A, controls) or perfused in the Langendorff apparatus for 20 min, followed by 5 min of global normothermic ischemia and 10 min of buffer perfusion (group B, preconditioning) or followed by two cycles of 2.5 min of global normothermic ischemia plus 5 min of buffer perfusion (group C, preconditioning). The hearts were then arrested and preserved for 6 hr with Bretschneider's histidine-tryptophan-potassium cardioplegic solution at 4 degrees C, followed by 30 min of reperfusion. Recovery of cardiac function, postischemic enzyme leakage, and intracellular calcium concentration were compared. RESULTS: After 6 hr of ischemia, the hearts that underwent preconditioning in groups B and C showed better recovery of left ventricular developed pressure (P<0.05), a lower end-diastolic pressure level (P<0.05), less leakage of creatine kinase, and a lower intracellular calcium concentration than those in group A. There were no statistical differences in the rate of recovery of coronary flow. CONCLUSIONS: Our study demonstrated that ischemic preconditioning improves myocardial functional recovery after 6 hr of hypothermic preservation in the isolated rat heart. Preconditioning might be useful for preserving the heart against long-term ischemia/reperfusion injury.

Animals↗
PubMed1998

Stimulatory effects of neopterin on hematopoiesis in vitro are mediated by activation of stromal cell function.

The pteridine neopterin (NP) was shown to be produced by monocytes and is known to be a useful marker of immunological activation, although, its biological activity is still unclear. Recently, we found that intravenous administration of NP increased the numbers of blood leukocytes, and granulocyte-macrophage progenitor cells (CFU-GM) in the bone marrow and spleens of mice. In order to elucidate the mechanism whereby NP stimulates hematopoiesis, the effects of NP on hematopoietic stem cell proliferation and differentiation in vitro were studied using a long-term bone marrow culture (LTMC) system with cloned stromal cell line, MS-5. Adding NP to the LTMC increased the numbers of cells in total, CFU-GM and colony-forming unit in spleen (CFU-S). NP also increased the number of CFU-GM in a soft agar culture system, but it did not enhance CFU-GM colony formation when target bone marrow cells were semi-purified (T, B and adherent cell-depleted bone marrow cells) and cultured in this system, suggesting that NP did not directly affect the proliferation of hematopoietic progenitors. Conditioned medium obtained from NP-treated stromal cells had much greater colony-stimulating activity than that obtained from untreated stromal cells. Furthermore, NP treatment stimulated the production of IL-6 and GM-CSF by stromal cells. All these findings suggest that NP stimulates hematopoietic cell proliferation and differentiation in vitro by activating stromal cell function.

Animals↗
PubMed1998

Association between the degree of platelet-derived growth factor-A chain mRNA expression and coronary arteriosclerosis in the transplanted heart.

Although intimal and medial proliferation of smooth muscle cells is recognized as one of the key mechanisms in the development of graft coronary arteriosclerosis, the role of platelet-derived growth factor (PDGF) in this process is still uncertain, because of the undetermined pathogenesis of graft coronary arteriosclerosis (GCA). In the present study, the correlation between the extent of GCA and the degree of PDGF-A chain expression in cardiac grafts was investigated in 21 rats with GCA of varying extent. Lewis rats underwent heterotopic heart transplantation from Wistar King donors and were treated with cyclosporine A (10 mg/kg/day) (n = 7), 15-deoxyspergualin (5 mg/kg/day) (n = 7), or Multiglycosidorum tripterygii (MT) (30 mg/kg/day) (n = 7). Histological evaluations of coronary arteriosclerosis, as well as Northern blot analysis of graft PDGF-A chain expression were made, 60 days after transplantation. Graft coronary arteriosclerosis of varying extent was observed among the 21 transplanted hearts. Significant correlations were found between the PDGF-A chain mRNA expression of cardiac allograft and the grade of arterial intimal thickening (Spearman's r = 0.76, P < 0.005) as well as the incidence of diseased vessels (r = 0.82, P < 0.001). The PDGF-A chain mRNA expression of the cardiac allograft is associated with the extent of GCA, indicating that PDGF-A plays an important role in the development of GCA.

Animals↗
PubMed1998

Should the aortic valve homograft be recryopreserved?

BACKGROUND: The number of homograft donors is limited and the once-thawed homograft may be unsuitable for the recipient and obliged to be wasted. The purpose of this study was to investigate the possibility of recryopreserving and using the once-thawed homograft for another patient. METHODS: Canine aortic valve leaflets were frozen to -80 degrees C by a programmed freezer, stored in liquid nitrogen, and thawed after 1 week. A subgroup of leaflets was left at 4 degrees C for 15 minutes, re-cryopreserved, and thawed after 1 week. Pathologic and flow cytometric evaluations were performed. RESULTS: After thawing, by pathology, alignment of the fibers was acceptably maintained but the membrane and cytoplasm of the fibroblast were damaged. These findings were not significantly aggravated even after rethawing. By flow cytometry, fibroblast viability was 90.7%+/-1.7% immediately after thawing, 87.6%+/-1.0% after thawing for 15 minutes at 4 degrees C, 63.7%+/-2.7% during refreezing at 0 degrees C, and 39.4%+/-4.3% after rethawing. CONCLUSIONS: From the standpoint of fibroblast viability, it is not possible to recryopreserve the once-cryopreserved and thawed aortic valve homograft.

Animals↗
PubMed1998

Organochlorine pesticides and polychlorinated biphenyl congeners in wild terrestrial mammals and birds from Chubu region, Japan: interspecies comparison of the residue levels and compositions.

In order to understand the residue levels of organochlorine compounds (OCs) and their accumulation patterns in wildlife inhabiting Chubu region, Japan, the concentrations of polychlorinated biphenyls (PCBs), hexachlorocyclohexane isomers (HCHs), DDT compounds (DDTs) and hexachlorobenzene (HCB) were measured in 8 species of terrestrial mammals and 10 species of birds. In view of feeding habits, the contamination levels of OCs were found to be higher in omnivorous mammals than in herbivorous ones, and in fish-eating ones and raptores than in omnivorous birds. In fox and dog, PCB-180 (2, 2', 3, 4, 4', 5, 5'-heptachlorobiphenyl) was the most dominant PCB congener, while in the other species PCB-153 (2, 2', 4, 4', 5, 5'-hexachlorobiphenyl) was the most persistent. The ratios of lower chlorinated PCB congeners (tri- to tetra-) to total PCBs were larger in fish-eating birds than in the other birds. The results indicate that the compositions of PCB congeners would reflect the differences of feeding habits and xenobiotic metabolizing systems among each species.

Animals↗
PubMed1998

Adenomatous hyperplasia with unusual imaging findings at combined helical CT hepatic arteriography and CT during arterial portography.

We examined a patient with a hepatocellular carcinoma and multiple adenomatous hyperplasias in the cirrhotic liver. Helical CT hepatic arteriography (CTA) showed the adenomatous hyperplasias as areas of discrete hypoattenuation, and the combined CT during arterial portography (CTAP) showed corresponding areas of subtle hyperattenuation. Such imaging findings at combined CTA and CTAP were seen in only one patient in a series of more than 80 patients in whom we performed angiographically-assisted CT. We demonstrate these unusual imaging findings of adenomatous hyperplasia in the report.

Adenoma↗
PubMed1998

Hepatodiaphragmatic portosystemic shunt in cirrhosis.

A case of an unusual form of hepatodiaphragmatic portosystemic shunt arising from the periphery of left posterosuperior portal vein branch, running beneath the inferior aspect of left hemidiaphragm and draining into the left lateral abdominal wall is demonstrated and assessed with digital subtraction portography, maximum-intensity-projection images reconstructed from helical CT during arterial portography and pulsed Doppler sonography with flow velocity measurement. This is a reported case of this unusual intrahepatic portosystemic shunt and discussion on the utility of current radiological techniques.

Abdominal Muscles↗
PubMed1998

Splenic adherent cells, stimulated in vitro, induce the reactive formation of lymphoid follicles and germinal centres in draining lymph nodes after subcutaneous transfusion into syngeneic mice.

The reactive formation of lymphoid follicles and germinal centres in lymph nodes, induced by subcutaneous transfer of in vitro activated splenic adherent cells into syngeneic mice, were studied. Adherent cells were obtained by incubating spleen cell suspensions for 24 h and activated by incubating for 1 h in the medium containing keyhole limpet haemocyanin (KLH) absorbed onto alumina. Some of the treated adherent cells were irradiated with 10 Gy x-rays, while others were either not stimulated or were stimulated with alumina-KLH but killed by repeated freezing and thawing. Examination of adherent cell smears immunostained with antibodies against, F4/80, Mac-1, Mac-2 and NLDC-145 indicated that many adherent cells displayed macrophage markers but few displayed the interdigitating cell marker. Animals transfused with KLH-treated adherent cells with or without irradiation showed a marked increase in the number of lymphoid follicles and germinal centres in draining lymph nodes, whereas those transfused with adherent cells which had not been KLH-treated or which had been killed after KLH treatment displayed no significant change in the number of follicles. These results were interpreted as indicating that following transfusion, antigen-activated adherent macrophages migrated into the draining lymph nodes and induced the reactive formation of lymphoid follicles and germinal centres outside preexisting follicles.

Adjuvants, Immunologic↗
PubMed1998

Clinical applicability of functional magnetic resonance imaging and activation study with single photon emission computerized tomography for functional mapping.

The purpose of this study is to estimate the clinical applicability of functional magnetic resonance imaging (f-MRI) combined with the activation study using single photon emission computerized tomography (SPECT) with special reference to identification of primary sensorimotor area. Five healthy volunteers and 5 patients with brain tumors located around the sensorimotor cortex were studied by both f-MRI with gradient echo and SPECT with 99mTc-ethyl cysteinate dimer using split-dose and subtraction method. In f-MRI study, the significant activation of the sensorimotor area was observed in all subjects. Various concurrent activation regions such as supplementary motor (2 volunteers vs. 4 patients), premotor (1 vs. 2) and ipsilateral sensorimotor area (1 vs. 2) were also observed. In the cases with the activation of neighboring regions of sensorimotor area, it was difficult to identify the area in f-MRI. In SPECT study, the sensorimotor area was depicted as the most increased area in regional cerebral blood flow in eight cases, the characteristics of which were helpful to diagnose the area, while significant activation of the area with edema could not be detected in two patients. Consequently, the sensorimotor area was cross-validated with both the modalities. This study demonstrated that it would be valuable to use both techniques for the clinical assessment of the sensorimotor area.

Adult↗
PubMed1998

Focal hepatic lesion detection: comparison of four T2-weighted MR imaging pulse sequences.

PURPOSE: To evaluate T2-weighted magnetic resonance (MR) imaging with conventional spin-echo, breath-hold fast spin-echo, respiratory-triggered fast spin-echo, and breath-hold multishot spin-echo echo-planar sequences for detection of focal hepatic lesions. MATERIALS AND METHODS: T2-weighted MR images obtained with the four sequences in 56 patients with 107 solid and 124 nonsolid lesions were retrospectively analyzed. Image review was conducted on a liver segment-by-segment basis; a total of 408 liver segments were reviewed separately and independently for solid and nonsolid lesions by three radiologists. Diagnostic accuracy was evaluated with receiver operating characteristic analysis. RESULTS: Lesion-to-liver contrast-to-noise ratio was highest with multishot echo-planar images of both solid and nonsolid lesions. Diagnostic accuracy for solid lesions was statistically significantly better with conventional spin-echo images than with any other type of image (P < .0001). Diagnostic accuracy for nonsolid lesions was statistically significantly better with respiratory-triggered fast spin-echo images than with any other type of image (P < .0001). Image quality was best with breath-hold fast spin-echo images. CONCLUSION: Conventional spin-echo MR imaging should not be replaced with breath-hold fast spin-echo or multishot spin-echo echo-planar imaging, despite the shorter acquisition times that are possible with the latter two sequences.

Female↗
PubMed1998

Primary modulation by oestradiol of the production of an oviduct-specific glycoprotein by the epithelial cells in the oviduct of newborn golden hamsters.

The effects of steroid hormones (oestradiol and progesterone) on the appearance of a golden hamster oviduct-specific glycoprotein (GHOGP) in the epithelium of the oviduct of the newborn golden hamster were investigated by immunoblotting and immunohistochemical staining with a GHOGP-specific monoclonal antibody. Newborn golden hamsters (1.5 days old) were injected daily with oestradiol (1 microgram) or progesterone (10 microgram). An oviductal extract of oestradiol-treated golden hamsters for 4 days apparently immunoreacted with the monoclonal antibody on a broad band with a molecular mass of more than 200 kDa by immunoblotting under reducing conditions. This broad band was consistent with the migration of GHOGP in an extract of adult oviducts. Consecutive daily injections of oestradiol induced the appearance of GHOGP in undifferentiated epithelial cells of the oviduct of neonates. In oviducts of oestradiol-injected animals, GHOGP was first detected in the Golgi region and then increased in amount to fill the supranuclear cytoplasm of the epithelial cells. The inductive effect of oestradiol was dose-dependent. In contrast, consecutive daily injections of progesterone had no effect on the appearance of GHOGP in the oviductal epithelium. The effects of oestradiol and progesterone in organ culture of oviducts were examined in vitro, by culturing oviductal organs from 1.5-day-old newborn golden hamsters in chemically defined medium supplemented with oestradiol or progesterone for 2 days and then subjected to immunohistochemical staining. The immunoreaction was detected only in the epithelial cells of oestradiol-treated oviducts at concentrations of > 0.01 ng ml-1, but not in the cells of untreated and progesterone-treated oviducts. These results indicate that the production of GHOGP in the epithelial cells of the oviduct of newborn golden hamsters is induced by oestradiol both in vivo and in vitro. It is suggested that oestradiol may be involved in the synthesis of GHOGP in the oviduct during postnatal development of golden hamsters.

Animals↗
PubMed1998

Nondiseased portal perfusion defects adjacent to the right ribs shown on helical CT during arterial portography.

OBJECTIVE: The purpose of our study was to assess the frequency and imaging characteristics of nonpathologic portal perfusion defects in subcapsular liver parenchyma adjacent to the right ribs as seen on CT hepatic arteriography combined with helical CT during arterial portography (CTAP). MATERIALS AND METHODS: From January 1994 to June 1997, helical CTAP and CT hepatic arteriography were performed in 94 patients with suspected malignant hepatic tumors. The patient group comprised 66 men and 28 women ranging from 37 to 83 years old (mean, 64 years old). Three radiologists retrospectively reviewed the images obtained by CTAP to evaluate portal perfusion defects adjacent to the right ribs for location, shape, size, and correlation with findings seen on CT hepatic arteriography. RESULTS: We identified 16 nonpathologic portal perfusion defects adjacent to the right eighth (n = 1), ninth (n = 12), and tenth (n = 3) ribs in 12 (13%) of 94 patients. The shapes of the 16 defects were circular (n = 1), oval (n = 7), wedge (n = 3), and irregular (n = 5). The defects were 10-30 mm in diameter (mean, 16.9 mm). In four (25%) of 16 locations, CT hepatic arteriography showed poorly identified, homogeneous, irregularly shaped areas of contrast enhancement corresponding to the defects seen on CTAP. The portal perfusion defects were proven to be nonpathologic on definitive surgery in four patients and on follow-up radiography in eight patients. CONCLUSION: Helical CTAP may show nonpathologic portal perfusion defects adjacent to the right ribs. Most defects did not appear circular but rather were oval, irregular, or wedge-shaped. CT hepatic arteriography infrequently showed corresponding findings. Radiologists should recognize this potential pitfall when interpreting images obtained by helical CTAP.

Adult↗
PubMed1998

Stimulatory effects of substance P on CD34 positive cell proliferation and differentiation in vitro are mediated by the modulation of stromal cell function.

Substance P (SP) is a neuropeptide widely distributed in the nervous system. Extensive study has shown SP stimulates production of various cytokines by bone marrow stromal cells, although, the role of SP in hematopoietic phenomena is still unclear. Recently, we established a human cloned stromal cell line, HAS303, which can support hematopoietic stem cell proliferation and differentiation in vitro. We used this culture system to examine the effects of SP. Expression of the mRNAs of neurokinin (NK)-1R, NK-2R and NK-3R, specific SP receptors, on HAS303 cells was demonstrated by the RT-PCR. CD34+ cells isolated from bone marrow were co-cultivated with HAS303 cells in the presence and absence of SP and the total hematopoietic cells and progenitors were counted every 5 days. Introducing SP (10(-8) M) to the co-cultures significantly increased the number of total cells and progenitors compared with control cultures. SP showed no enhancing activity on CD34+ cells cultured alone. SP also stimulated IL-3-dependent colony formation of whole bone marrow MNCs in a soft agar culture system, but showed no such activity on isolated CD34+ cells in this system. These observations suggest that SP stimulated HAS303 cells, activated HAS303 cells, and stimulated the proliferation and differentiation of CD34+ cells. Treating HAS303 cells with SP increased the intracellular Ca2+ concentration and stimulated production of G-CSF, GM-CSF, SCF and IL-6, but not IL-1alpha, IL-1beta and TNF-alpha, but did not enhance proliferation. All these findings suggest that SP mediates hematopoietic cell proliferation and differentiation in vitro by activating stromal cell function.

Antigens, CD34↗
PubMed1998

Local health care system utilizing the LPG (liquid propane gas) network.

JAC's LPG monitoring network system is mainly provided in mountain villages. However, by using this system, it will be possible to start a Digital Network Program for the Elderly while maintaining superior economic feasibility and public benefit using existing information infrastructures. This project also has the capabilities for the creation of a fire/disaster monitoring system, as well as a health care system by using conventional LPG monitoring systems. Telemedicine is an option for the future, as well, by connecting medical equipment and a tele-conferencing system.

Aged↗
PubMed1998

Enhanced engraftment of intravenously transplanted hematopoietic stem cells into bone marrow of irradiated mice treated with AcSDKP.

The effect of the tetrapeptide Acetyl-N-Ser-Asp-Lys-Pro (AcSDKP) on intravenously transplanted hematopoietic stem cell engraftment into the bone marrow (BM) of irradiated mice was studied. When 5 x 10(4) marrow cells were transplanted into lethally irradiated mice given 10 microg AcSDKP, the survival of these animals 4 weeks posttransplantation increased markedly from 20.0 +/- 4.4% to 86.1 +/- 4.8%, the same result as that obtained from mice transplanted with 5 x 10(5) cells without AcSDKP treatment. Increased numbers of hematopoietic stem cells, including spleen colony-forming unit and colony-forming unit granulocyte-macrophage, were observed in the BM of AcSDKP-treated mice 1 and 8 days after transplantation. This finding suggested that AcSDKP influenced homing of hematopoietic stem cells into the BM of lethally irradiated animals. This enhancing activity of AcSDKP was neutralized by the simultaneous administration of an anti-AcSDKP polyclonal antibody. Furthermore, recovery of leukocytes in peripheral blood occurred faster in AcSDKP-treated than in untreated transplanted mice. These findings may provide a basis for the clinical use of AcSDKP in BM transplantation patients.

Animals↗