Biomedical subjects

K Hioki

Publications and source records attributed to K Hioki.

At least 37 records · Page 2Linked to original sources

PubMed1998

Participation of nitric oxide in the mucosal injury of rat intestine induced by ischemia-reperfusion.

The dual role of nitric oxide as a cytoprotective or a cytotoxic free radical gas has been noted in various types of pathophysiological conditions, including the digestive system. The aim of this study was to examine the role of nitric oxide in the mucosal injury induced by ischemia-reperfusion in the rat small intestine. A transient intestinal ischemia was produced in the catheterized ileal segments of rats by occluding the anterior mesenteric artery for 60 min. Nitric oxide metabolites (NO2- and NO3-) and lactate dehydrogenase activity in perfusates of the intestinal lumen were measured over 5 hr periods. The time-course of histological changes in small intestine was also observed. After ischemia-reperfusion, nitric oxide release in the intestinal lumen increased significantly and the dynamics of nitric oxide release correlated with that of lactate dehydrogenase leakage. The administration of NG-nitro-L-arginine methyl ester (1.0-2.5 mg/kg) inhibited this increased nitric oxide release and the lactate dehydrogenase leakage and afforded protection against the mucosal injury induced by ischemia-reperfusion. In conclusion, the nitric oxide production that was accelerated by ischemia-reperfusion of small intestine may possibly participate in the breakdown of intestinal mucosa after ischemia-reperfusion insult.

Animals↗

PubMed1997

Mechanisms underlying apoptosis induced by combination of 5-fluorouracil and interferon-gamma.

Several investigators have reported on the clinical effects of 5-fluorouracil (5-FU) or the combination of 5-FU plus interferon-gamma (IFN-gamma) on patients with advanced colorectal carcinoma. It has also been reported that apoptosis induced by 5-FU is due to the effects on DNA synthesis and functional RNA synthesis. In the present study, we examine the biological mechanisms underlying 5-FU or the combination of 5-FU plus IFN-gamma, using the colorectal carcinoma cell line, COLO 201, 5-FU and IFN-gamma independently or additively induced apoptosis in COLO 201 in a dose- and time-dependent manner, which was correlated with the down-regulation of Bcl-2 and the up-regulation of Bax. An interleukin-1 beta-converting enzyme (ICE)-like protease inhibitor (but not an ICE-inhibitor) blocked apoptosis induced by only 5-FU. These results suggest that 5-FU has the capacity to induce apoptosis in COLO 201, resulting from the up-regulation of Bax; the apoptosis-inducing signal of 5-FU seems to be different from that of IFN-gamma. Thereby, 5-FU and IFN-gamma have additional effects on the induction of apoptosis. This finding provides an experimental basis for clinical therapy using 5-FU and/or IFN-gamma for colorectal cancer.

Adenocarcinoma↗

PubMed1997

Pyloroduodenal duplication cyst: case report

A 6-day-old female presented with vomiting and an abdominal mass. At laparotomy, a pyloroduodenal duplication cyst was enucleated from the pyloric region. Of the diagnostic studies performed, IV cholangiography with spiral computed tomography and an upper gastrointestinal barium study were useful in the preoperative differential diagnosis.

Journal Article↗

PubMed1997

Jejunal pouch and interposition reconstruction after total gastrectomy for cancer.

The authors modified the operative procedures used in pouch and interposition (PI) reconstruction in an attempt to improve the surgical results after total gastrectomy, because a randomized controlled trial had revealed that the clinical assessment of PI was quite poor, even though it is a physiological route. In most of the treated patients, the gastric emptying test revealed delayed emptying, and an X-ray video film showed folding and twisting of the jejunal conduit between the pouch and duodenum, which disturbed the transmission of nutrition. Modified PI (m-PI) was performed by decreasing the length of the jejunal conduit and widening the mesenteric pedicle to preserve the blood and nerve supply. This procedure was retrospectively compared with the previously used PI reconstruction by evaluating the postprandial symptoms, food intake, body weight, serum nutritional parameters, and emptying time of the gastric substitute. The m-PI group (n = 6) showed a lower incidence of symptoms, a greater food intake, and a greater weight recovery than the PI group (n = 6). The gastric emptying test also revealed an acceptable degree of emptying. We thus conclude that the m-PI reconstruction is more useful for improving the postoperative quality of life than the previously used method of PI reconstruction.

Adult↗

PubMed1997

New immunodeficient (nude-scid, beige-scid) mice as excellent recipients of human skin grafts containing intraepidermal neoplasms.

Engraftment of normal or lesional human skin onto nude or SCID (severe combined immunodeficiency) mice has been used as an in vivo experimental model. However, this model has some limitations, such as shrinkage and loss of the grafted skin over time. To improve the experimental model, we have produced two new SCID-lineage mouse strains, BALB/cA-nude-scid (nu/nu, scid/scid) and BALB/cA-beige-scid (bg/bg, scid/scid) mice, by the method of cross intercross. Intraepidermal neoplastic lesions such as Bowen's disease were grafted onto the back of the mice of these strains. The rate of reduction in the size of the grafts was lower on nude-scid and beige-scid mice than on SCID mice. Rates of survival of neoplastic cells in the grafts were higher in nude-scid mice than in SCID and beige-scid mice (SCID mice 38%, nude-scid mice 55%, beige-scid mice 38%). Neoplastic cells of Bowen's disease grafted onto a beige-scid mouse proliferated and invaded the dermis during 233 days of observation, confirming the progression to invasive squamous cell carcinoma from carcinoma in situ. The present study revealed that nude-scid and beige-scide mice newly produced by us provide a very useful in vivo experimental model for the investigation of carcinogenesis and tumor progression in human skin.

Animals↗

PubMed1997

TgPVR21 mice for testing type-3 oral poliovirus vaccines: role of clinical observation and histological examination.

Transgenic mice susceptible to poliovirus (TgPVR mice) have been used to study poliovirus neurovirulence and attenuation. It was shown recently that mouse line TgPVR21 may be a suitable model to evaluate neurovirulence safety of oral poliovirus vaccine. It was important to determine whether TgPVR21 mice are sensitive enough to discriminate between type-3 reference and 'marginal' vaccines, i.e. those that failed the monkey test while containing only slightly increased amounts of neurovirulent revertants at position 472 of the viral genome as measured by a molecular assay MAPREC. Data presented here demonstrate that TgPVR21 mice are not less sensitive than monkeys in the detection of marginal vaccines. In contrast to the monkey neurovirulence test, which is based on histological examination of the CNS, the TgPVR21 mouse neurovirulence test revealed marginal vaccines by simple analysis of clinical signs without requiring a laborious histological examination.

Animals↗

PubMed1997

Inhibition of tumor growth and metastasis by angiogenesis inhibitor TNP-470 on breast cancer cell lines in vitro and in vivo.

Antitumor and antimetastatic activity of the angiogenesis inhibitor O-(chloroacetyl-carbamoyl) fumagillol (TNP-470), a semisynthetic analogue of fumagillin, was evaluated in breast cancer cell lines. In an in vitro MTT assay, after 72 hrs continuous exposure to TNP-470, growth inhibition was observed in all seven cell lines of murine (JYG-A, JYG-B, DD-762, and BALB/c-MC) or human (KPL-1, MDA-MB-231, and MKL-F) origin, in which the 50% inhibitory concentrations (IC50) at 72 hrs treatment were 4.6, 4.4, 4.6, 10.1, 35.0, 25.3, and 33.4 micrograms/ml, respectively. In an in vivo assay using JYG-A, JYG-B, KPL-1, and MDA-MB-231 cells by orthotopic (right thoracic mammary fat pad) transplantation in female nude mice, TNP-470 at 30 or 50 mg/kg body weight was injected s.c. every other day from the day of tumor cell inoculation until the end of the experiment. The inhibitory effect on primary tumor growth was obtained in all four cell lines in a dose-dependent manner. In the 50 mg/kg TNP-470-treated group, the reductions in tumor weight of the JYG-A, JYG-B, KPL-1, and MDA-MB-231 cells with respect to the controls were 50%, 30%, 4%, and 49%, respectively. Metastasis was seen in the JYG-A, JYG-B, and KPL-1 cells. The numbers of mice bearing pulmonary metastases of JYG-A and JYG-B cells and regional axillary lymph node metastases of KPL-1 cells were reduced, and TNP-470 at the 50 mg/kg dose to KPL-1 cells significantly reduced lymph node metastases compared with the control. Although the weight gain was retarded in the TNP-470-treated mice, weight loss was not seen. TNP-470 was highly effective in the treatment of breast cancer cells. These results suggest that the clinical use of TNP-470 may be a promising treatment for breast cancer patients.

Animals↗

PubMed1997

Suppression of intestinal polyp development by low-fat and high-fiber diet in Apc(delta716) knockout mice.

Most epidemiological and animal studies show a positive correlation of the dietary intake of fat with the incidence of colon cancer, whereas an inverse correlation of the dietary intake of fiber. In rats fed a diet low in fat and high in wheat bran fiber and calcium, a significant decrease was reported in the number of azoxymethane-induced aberrant crypt foci compared with those fed a high-fat, low-fiber and low-calcium diet. Mutations in the human APC gene play a key role, not only in familial adenomatous polyposis, but also in many sporadic cancers of the entire digestive tract. We previously constructed a mouse strain Apc(delta716), carrying a truncation mutation at codon 716 of the Apc gene, the homolog of human APC (10). The heterozygous mice developed numerous intestinal polyps, and all microadenomas dissected from the earliest polyps had already lost the wild-type allele, indicating the loss of heterozygosity. Using these Apc(delta716) knockout mice, we have investigated the effect of a low-fat and high-fiber diet (LRD for 'low-risk' diet) on intestinal polyposis, and compared it with that of a high-fat and low-fiber diet (HRD for 'high-risk' diet). The mice were fed either diet for 7 weeks, and the number and size of intestinal polyps were scored. The LRD-fed mice had fewer polyps than the HRD-fed mice, by 36% in the small intestine and by 64% in the colon. As for the polyp size distribution, there was no significant difference between the HRD- and LRD-fed mice. These results indicate that LRD can suppress intestinal polyposis compared with HRD which does not, and suggest that its suppression is at the initiation of polyp formation. This is likely to be due to a decreased frequency of loss of heterozygosity, rather than a retarded growth of the polyp adenomas.

Animals↗

PubMed1997

Inactivated poliovirus vaccine protects transgenic poliovirus receptor mice against type 3 poliovirus challenge.

Transgenic (Tg) mice expressing the human poliovirus receptor (PVR) were vaccinated with inactivated poliovirus vaccine (IPV) and evaluated for induced immunity against type 3 poliomyelitis. One injection of monovalent type 3 IPV elicited protective immunity against wild-type poliovirus. In contrast, 2 injections of trivalent IPV were required for protection. Neutralizing antibody response and protection were vaccine dose-dependent. Administration of polio-immune mouse plasma protected unimmunized mice, demonstrating that neutralizing antibody was sufficient for immunity. IPV heated to remove its D antigen component did not induce protection in Tg PVR mice. IPV derived from a wild-type poliovirus strain gave better protection against wild-type viral challenge than IPV derived from an attenuated poliovirus strain. The newly developed Tg PVR mouse-protection test may be useful in evaluating existing IPV potency tests and for attempts to improve formulations of trivalent IPV or combined vaccines for childhood immunization schedules.

Animals↗

PubMed1997

Primary human immunodeficiency virus type 1 viremia and central nervous system invasion in a novel hu-PBL-immunodeficient mouse strain.

We established four new mouse strains with defective T and B cells as well as defects in innate immunological reactions using an NK cell depletion antibody and showed that all mutant mouse strains efficiently received human peripheral blood leukocyte (PBL) engraftment (hu-PBL-scid mice). Higher levels of human immunodeficiency virus type 1 (HIV-1) replication were observed in these new hu-PBL-scid mice than in conventional hu-PBL-C.B-17-scid mice. In one particular strain, hu-PBL-NOD-scid mice, high levels of HIV-1 viremia (more than 10(6) 50% infectious doses per ml) were detected after infection with HIV-1. The plasma viral load was about 100 to 1,000 times higher than that observed in other hu-PBL-scid mice infected with HIV-1. Although high-level viremia did not correlate with the total amount of HIV-1 RNA in cells from infected mice, high levels of free virions were detected only in hu-PBL-NOD-scid mice. HIV-1 viremia induced systemic HIV-1 infection involving the liver, lungs, and brain. PCR in situ hybridization confirmed that HIV-1-infected cells invaded the brain tissue of the hu-PBL-NOD-scid mice. Our results suggest that the genetic background, including innate immunity, is critical in the development of primary HIV-1 viremia and subsequent central nervous system invasion with HIV-1. The hu-PBL-NOD-scid mouse represents a useful model for the study of the pathogenesis of HIV-1 in vivo, especially brain involvement, and therapy of primary HIV-1 viremia.

Animals↗

PubMed1997

Chemotherapeutic profiles of human tumors implanted in SCID mice showing appreciable inconsistencies with those in nude mice.

Sensitivities to antitumor drugs of human tumor xenografts (HTXs) implanted in C.B-17-scid and in BALB/cA-nu were compared to examine whether genetic backgrounds of immune deficiency of the host mice influenced the chemotherapeutic profiles of implanted tumors. In a total of 25 pairs of corresponding experiments with each host mouse strain (5 HTXs x 5 drug treatment groups), we obtained consistent results in 23 (92.0%) experiments consisting of 10 which were both significantly effective and 13 which were both ineffective, although the remaining two (8.0%) experiments showed inconsistent results. A human T-cell lymphoma cell line, LM-2-JCK, implanted in nude mice, was resistant to treatment with 65 mg/kg of cyclophosphamide, but this tumor showed sensitivity to the same treatment when implanted in either SCID mice or mice with a recombination activating gene 2 defect [BALB/cA-TgH (Rag2)], suggesting that the genetic immune background of the host mouse should not be overlooked as a factor affecting tumors.

Animals↗

PubMed1997

Pneumocystis carinii cysts are susceptible to inactivation by chemical disinfectants.

The inactivation efficacy of eight disinfectants commonly used in laboratories and animal rooms to inactive Pneumocystis carinii cysts was estimated by experimental infection in C.B-17-scid mice. The disinfectants examined in this study were 70% ethyl alcohol, 10% iodoform, 0.5% hypochlorous acid, two 1% quanternary ammonium salts, 3% hydrogen peroxide, sodium chlorite and 1% cresol soap. The lung homogenates from P. carinii infected C.B-17-scid mice were treated with each disinfectant for 15 min at room temperature, washed with saline, and inoculated into C.B-17-scid mice. Eight weeks after inoculation, lungs from these mice were examined by staining with toluidine blue O to detect P. carinii cysts. PCR amplifying 346 bp of P. carinii specific mitochondrial ribosomal RNA large segments was also performed using DNA extracted from the lungs of the mice. As a result, seven disinfectants, excepting for 0.5% hypochlorous acid, were effective in the inactivation of P. carinii cysts. These results suggest that P. carinii cysts were sensitive to chemical disinfectants even though they have been commonly considered as insensitive.

Animals↗

PubMed1997

Pyloroduodenal duplication cyst: case report.

Cholangiography↗

PubMed1997

Cytokine gene expression in the foot pad and spleen of BALB/cAJcl mice infected with M. leprae.

The cytokine mRNAs expressed in the foot pads and spleens of BALB/cAJcl mice infected with Mycobacterium leprae were studied by the reverse transcriptase-polymerase chain reaction (RT-PCR) method using cytokine-specific primers for interleukin-1 alpha (IL-1 alpha), -2, -4, -6, -10, -12-(p40), gamma interferon (IFN-gamma), tumor necrosis factor-alpha (TNF-alpha), and TNF-beta, and then for CD4 and CD8 markers. The pattern of cytokine gene expression in the foot pad which supports M. leprae growth was different from the expression in the spleen which does not permit M. leprae multiplication in mice. Before BALB/cAjcl mice were infected with M. leprae, IL-1 alpha and TNF-beta mRNAs were expressed physiologically in the foot pad while all of the cytokine genes examined were expressed in the spleen. In the foot pads of mice inoculated with M. leprae, in addition to the physiological appearance of IL-1 alpha and TNF-beta mRNAs, these signals were intensified. TNF-alpha expression was induced by the infection. On the other hand, in the spleens of mice inoculated with M. leprae, CD4 mRNA expression disappeared on day 1 of the infection, which was accompanied by the reduced expression of IL-2, -4, -6, and -12 mRNAs. The recovery of CD4 mRNA expression at a latter stage was accompanied by a corresponding increase of the cytokine mRNA expression. It was suspected that these results might permit restricted growth of M. leprae in the foot pads of normal mice. Furthermore, our study suggests that tissue-specific, local, immunologic characteristics are important in M. leprae growth.

Animals↗

PubMed1997

[Jejunal pouch and interposition reconstruction after a total gastrectomy for cancer].

The authors modified the operative procedures used in pouch and interposition (PI) reconstruction in an attempt to improve the surgical results after a total gastrectomy, because a randomized controlled trial had revealed that the clinical assessment of PI was quite poor, even though it is a physiological route. In most of the treated patients, the gastric emptying test revealed delayed emptying, and an X-ray video film showed folding and twisting of the jejunal conduit between the pouch and duodenum, which disturbed the transmission of the nutrition. Modified PI (m-PI) was performed by decreasing the length of the jejunal conduit and widening the jejunal pedicle to preserve the blood and nerve supply. The m-PI group showed a lower incidence of symptoms, a greater food intake, and a greater weight recovery than the PI group. The gastric emptying test also revealed an acceptable degree of emptying. We conclude that the m-PI reconstruction is more useful for improving the postoperative quality of life than the previously used method of PI reconstruction.

Anastomosis, Surgical↗

PubMed1996

Induction of tolerance in murine autoimmune diabetes by transient blockade of leukocyte function-associated antigen-1/intercellular adhesion molecule-1 pathway.

The present study demonstrated that a short-term administration of mAbs against leukocyte function-associated antigen-1 (LFA-1) and intercellular adhesion molecule-1 (ICAM-1) at critical periods resulted in complete protection of autoimmune diabetes in non-obese diabetic (NOD) mice. When these mAbs were administered for only 6 days at 2 wk of age, neither diabetes nor insulitis was observed at 30 wk of age. It appears that the tolerance against beta cell Ag(s) was induced by this transient blockade of the LFA-1/ICAM-1 pathway. Protective suppressor activity was not enough to prevent diabetes because co-transfer of splenocytes from female NOD mice, which had received these mAbs at 2 wk of age, resulted in only a short delay of the diabetic onset caused by adoptive transfer of splenocytes from acutely diabetic NOD mice. Transfer of these splenocytes to young NOD mice could not also abrogate the spontaneous diabetes and insulitis. Furthermore, cyclophosphamide treatment could not abrogate the protection. When splenocytes from the treated NOD mice were transferred to NOD-SCID mice, none of the recipient mice developed significant insulitis and subsequent overt diabetes, suggesting the absence or the inactivation of diabetogenic effector T cells. However, splenic T cells from the insulitis-free NOD mice that had received the mAb treatment preserved proliferative responses to both islet cells and 65-kDa glutamic acid decarboxylase (GAD65) in vitro. These results suggest that a unique peripheral tolerance was induced by the transient blockade of the LFA-1/ICAM-1 pathway in an early age of NOD mice.

Adoptive Transfer↗

PubMed1996

Management of intestinal obstruction after gastrectomy for carcinoma.

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Gastrectomy↗

PubMed1996

A poliovirus-susceptible transgenic mouse model as a possible replacement for the monkey neurovirulence test of oral poliovirus vaccine.

Two poliovirus-susceptible transgenic mouse (Tg PVR) strains, Tg1 and Tg21, were compared with the monkey test for their sensitivity to neurovirulence of live oral poliovirus vaccine (OPV). Intracerebral (i.c.) and intraspinal (i.s.) routes of inoculation were investigated to determine the most suitable combination of mouse strain and route. Evaluation of the mouse tests was performed using several indicators; clinical score and failure time were selected as the most efficient. Tg1 and Tg21 mice inoculated i.s. with type 2, and Tg21 mice inoculated i.s. with type 3 OPV were determined to be the most appropriate systems, whereas they are shown not to be suitable for type 1 OPV. The sensitivity of each of the two mouse models was at least equal to that of the monkey test, suggesting that these mouse systems might be considered as a potential replacement for the monkey test of OPV. However, more data are needed to establish regulatory criteria of acceptability for vaccine lots tested in Tg PVR mice. This is the first study conducted with Tg PVR mice with all three types of poliovirus vaccine preparations.

Animals↗