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Biomedical subjects

Y Fukuda

Publications and source records attributed to Y Fukuda.

At least 19 recordsLinked to original sources
PubMed1995

Simultaneous evaluation of nitric oxide synthesis and tissue oxygenation in rat liver allograft rejection using near-infrared spectroscopy.

Near-infrared (NIR) spectroscopy was applied to rat liver allografts for assessing nitric oxide (NO) synthesis and tissue oxygenation as a means of monitoring the rejection response following liver transplantation. Orthotopic liver transplantation was performed in rats, which were assigned to three groups as follows: group 1, a syngeneic combination (lewis to Lewis); group 2, an allogeneic combination (ACI to Lewis); and group 3, an allogeneic combination treated with 15-deoxyspergualin. NIR spectroscopy was performed on the grafts in recipients, and the relative changes in nitrosyl-Hb (NO bound to erythrocyte hemoglobin), oxy-Hb, and oxidized cytochrome oxidase (Cyt.aa3) were obtained. The level of nitrosyl-Hb was significantly elevated from postoperative day (POD) 3 in group 2 compared with that in group 1, which remained constant (P < 0.05). In group 3, the elevation was significantly suppressed. These data indicate that the alloimmune response is associated with a dramatic change in NO synthesis in grafted livers. In a separate experiment, NO synthesis was also increased after long cold preservation (24 hr) in syngeneic liver transplants. However, the increase was transient and subsided on POD 3. Levels of oxy-Hb and oxidized Cyt.aa3 in group 2 were significantly decreased when parenchymal disorder was confirmed histologically (POD 6 and 8), compared with those in group 1, which remained constant (P < 0.05). In group 3, both of these levels showed improvement. Thus, our NIR spectroscopy technique was shown to be capable of assessing simultaneously both the immune response and the degree of immune-induced destruction of allograft tissue following liver transplantation through monitoring of NO synthesis and tissue oxygenation.

Animals↗
PubMed1995

Sensitive detection of circulating hepatocellular carcinoma cells in peripheral venous blood.

BACKGROUND: This study was performed to develop a sensitive method for the detection of circulating hepatocellular carcinoma (HCC) cells in peripheral blood, in advance of the diagnosis of distant metastasis of HCC by conventional means. METHODS: Peripheral blood (5 ml) samples were obtained from 64 patients with HCC and from 48 control subjects (31 patients with benign liver disease, 8 with metastatic liver cancer, and 9 with normal liver function). To identify HCC cells in peripheral blood, liver-specific human alpha-fetoprotein (hAFP) mRNA was amplified from total RNA extracted from whole blood by reverse transcriptase-polymerase chain reaction. RESULTS: Human alpha-fetoprotein mRNA was detected in 23 blood samples from the HCC patients (23/64, 36%), in 17 patients in whom there was no clinical evidence of distant metastasis. In contrast, there were no control patients whose samples showed detectable hAFP mRNA in the peripheral blood. The presence of hAFP mRNA in blood seemed to be correlated with the stage (by TNM classification) of HCC, the serum hAFP value, and the presence of intrahepatic metastasis, portal vein thrombosis, and/or distant metastasis. CONCLUSIONS: Reverse-transcriptase polymerase chain reaction is a very sensitive method for detecting circulating HCC cells. With this technique, important information for the management of HCC can be acquired, such as the indications for orthotopic liver transplantation in HCC patients. Moreover, use of this detection method may encourage investigation of the mechanism of metastasis in HCC.

Adult↗
PubMed1995

Morphologic and morphometric evaluation of the effect of ICRF-187 on bleomycin-induced pulmonary toxicity.

Morphologic and morphometric studies were made of the protective effects of ICRF-187 against the pulmonary damage induced by bleomycin in male and female C57/BL6 mice. Sixty minutes prior to the subcutaneous administration of 15 mg/kg of bleomycin, animals received either saline or ICRF-187 (300 or 150 mg/kg) intraperitoneally, twice a week for 4 weeks. The lungs of animals treated with bleomycin alone showed inflammation, hyperplasia of type II epithelial cells, squamous cell metaplasia and fibrosis. The extent of fibrosis was quantified by means of a color videometric system and histologic sections of lung stained according to a modified Masson trichrome method. The severity of these alterations, particularly of fibrosis, was reduced in all groups of animals pretreated with ICRF-187. The fibrosis was reduced to a similar extent in female mice treated with the 300 mg/kg and the 150 mg/kg doses of ICRF-187, from 39.3% to 17.6% and 13.3%, respectively. ICRF-187 induced significantly different degrees of reduction in fibrosis in the 2 groups of male mice treated with the 150 mg/kg and the 300 mg/kg doses, from 30% to 19.7% and 12.2%, respectively. In vitro studies indicated that both ICRF-187 and its open-ring hydrolysis product (ADR-925) remove iron slowly from the bleomycin-iron complex. This observation provides a basis for the concept that ICRF-187 protects by chelating iron involved in the formation of the bleomycin-Fe3+ complex that generates reactive oxygen radicals capable of causing pulmonary damage.

Animals↗
PubMed1995

Specific deficit of the ON response in visual transmission by targeted disruption of the mGluR6 gene.

Taking advantage of the restricted expression of metabotropic glutamate receptor subtype 6 (mGluR6) in retinal ON bipolar cells, we generated knockout mice lacking mGluR6 expression. The homozygous mutant mice showed a loss of ON responses but unchanged OFF responses to light. The mutant mice displayed no obvious changes in retinal cell organization nor in the projection of optic fibers to the brain. Furthermore, the mGluR6-deficient mice showed visual behavioral responses to light stimulation as examined by shuttle box avoidance behavior experiments using light exposure as a conditioned stimulus. The results demonstrate that mGluR6 is essential in synaptic transmission to the ON bipolar cell and that the OFF response provides an important means for transmitting visual information.

Animals↗
PubMed1995

Evidence of redox-linked signaling for producing a giant signal complex.

Previously we showed that a thiol-reactive heavy metal, HgCl2, crosslinked multiple cell surface receptors through a ligand-independent pathway, which produced massive aggregates of phosphotyrosine (PTYR)-containing proteins beneath plasma membrane [Nakashima et al. (1994): J Immunol 152: 1064-1071]. In this study we characterized these unique aggregates at the molecular level. The lysates in Brij 96 of thymocytes treated with HgCl2 were separated into the supernatant and pellet fractions by simple centrifugation. Selected PTYR-containing proteins and p56lck appeared in the pellet fraction as quickly as 5 s after exposure to HgCl2, and were further increased in amount by 5 min. Although the mechanism of triggering these events was redox-linked, the majority of proteins in the Brij 96-insoluble aggregates were dissociated in SDS-PAGE under nonreducing condition. This suggested that PTYR-containing proteins and p56lck themselves do not form dimer or polymer directly by thiol-mediated bond. The pellet fraction was further found to include some other signal delivery elements, such as GTPase activating protein, phosphatidylinositol 3 kinase, and mitogen-activated protein kinase. Finally, all of these signal elements and selected PTYR-containing proteins were collected in the same fraction by the sucrose density gradient centrifugation. These results suggest a unique redox-linked pathway of formation of a giant signal complex.

Animals↗
PubMed1995

Number and dendritic morphology of retinal ganglion cells that survived after axotomy in adult cats.

Retinal ganglion cells (RGCs) of adult cats were labeled by injection of diI into the proximal stump of completely transected optic nerves. Approximately 2% to 5% of the RGC population appeared viable 2 months after these axotomies, based on diI retention. The morphological type and dendritic arbor of these surviving RGCs were examined after intracellular injections of Lucifer Yellow into diI-labeled RGCs. Postaxotomy survival rate was much higher for alpha-like cells than for beta-like cells. However, in one of four retinas examined, a large number of RGCs seemed to survive axotomy, and among these, beta cells survived at an unusually high rate. Dendritic arbors of surviving RGCs were also examined after intracellular injection of horseradish peroxidase. Some dendrites of these RGCs lacked branches and were thin in caliber. Other dendrites displayed many spiny processes and bulbous swellings. Essentially, these results confirm the previous suggestion that alpha cells survive axotomy longer than beta cells. The ability of alpha cells to regenerate axons may thus be attributable to their relatively high resistance to axotomy. The atypical dendritic profiles seen after optic nerve transection may reflect either degeneration or regrowth of dendrites.

Animals↗
PubMed1995

Human herpesvirus-6 infection in renal allografts: retrospective immunohistochemical study in Japanese recipients.

This study was conducted to determine the incidence and clinical significance of human herpesvirus-6 (HHV-6) infection in renal allografts. A total of 105 biopsy specimens from 72 recipients were immunohistochemically examined for the presence of HHV-6 antigen, which localized in the distal tubular epithelial cells and in a few lymphocytes infiltrating into the interstitium. HHV-6 antigen in the tubular epithelia was detected in 63 (61.2%) specimens. Categorically, a higher incidence of the antigen was noted in specimens of accelerated rejection (3/4, 75.0%), acute rejection (28/3, 73.7%), and cyclosporin nephropathy (8/11, 72.7%). The antigen was present and absent an almost equal number of times in the categories of chronic rejection, intraoperative and routine protocol biopsies. Repeated biopsies were performed in six cases showing HHV-6 antigen, only one of which underwent transplant nephrectomy due to severe chronic rejection. Single or multinucleated giant cells in distal tubuli occurred in 10 (9.5%) specimens in a scattered manner. All of them were diagnosed as acute or chronic rejection. The giant cells showed no immunoreactivity for HHV-6, cytomegalovirus, or herpes simplex virus. These results indicate overall that HHV-6 infection is common in renal allografts and might be reactivated in acute rejection or cyclosporin nephropathy. The presence of HHV-6 antigen, however, does not necessarily correlate with a poor prognosis for the renal graft nor with the occurrence of giant cells in distal tubuli.

Adult↗
PubMed1995

Detection of immunoreactive antigen, with a monoclonal antibody to measles virus, in tissue from a patient with Crohn's disease.

Using immunofluorescence (IF), we investigated reactive antigens present in Crohn's disease patients with monoclonal antibodies derived from cells infected with measles virus, but not with the subacute sclerosing panencephalitis virus. During immunoblotting, one monoclonal antibody (mAb 86) reacted with a polypeptide with a molecular weight of 36,000 dalton (M; matrix protein) in measles virus-infected cells. This monoclonal antibody displayed a positive reaction only with tissues from patients with Crohn's disease by the IF test. It did not react with samples from patients with other chronic inflammatory bowel diseases, such as ulcerative colitis. Other monoclonal antibodies to the measles virus protein, and monoclonal antibodies to Herpes simplex virus type 1 did not react with the same tissue samples. The role of measles virus infection and/or a viral antigen (possibly the M protein) as a causative agent in Crohn's disease poses a challenging avenue for further research.

Antibodies, Monoclonal↗
PubMed1995

Abnormal contralateral kidney in unilateral multicystic dysplastic kidney disease.

We performed a retrospective study of infants with unilateral multicystic dysplastic kidney (MCDK) in order to investigate the associated urological abnormalities. We examined the records of seven patients, in five of whom a diagnosis had been made prenatally using ultrasonography. Our investigation focused on the associated urological abnormalities, particularly on the contralateral side, and the results of voiding cystourethrography (VCUG). Four of the seven patients (57%) had urological abnormalities other than MCDK: three exhibited vesicoureteral reflux (VUR) of the contralateral side including one patient who also had an ipsilateral ectopic ureter, and the fourth patient had a ureterocele of the ipsilateral side. The results indicate that contralateral VUR, was the most common abnormality associated with MCDK. Two infants had high-grade VUR and underwent anti-reflux surgery soon after the diagnosis. Both have remained free of recurrent urinary tract infection.

Female↗
PubMed1995

Abnormalities in elastic fibers and other connective-tissue components of floppy mitral valve.

Histologic, immunohistochemical, and ultrastructural studies were performed on 12 floppy mitral valves, 4 mitral valves showing focal myxomatous changes without prolapse, and 3 normal mitral valves. All floppy mitral valves were thickened by deposits of proteoglycans and also showed diverse structural abnormalities in collagen and elastic fibers. From these observations we conclude that (1) the structure of all major components of connective tissue in floppy mitral valves is abnormal; (2) alterations in collagen and accumulations of proteoglycans are nonspecific changes that may be caused by the abnormal mechanical forces to which floppy mitral valves are subjected because of their excessively large surface area; (3) the presence of excessive amounts of proteoglycans may interfere with the normal assembly of collagen and elastic fibers; (4) abnormalities of elastic fibers resemble those in other conditions characterized by structural dilatation or tissue expansion; and (5) alterations in elastin could result from defective formation, increased degradation, or both.

Actin Cytoskeleton↗
PubMed1995

Changes of compound action potentials in retrograde axonal degeneration of rat optic nerve.

Electrophysiological recordings of compound action potentials (CAPs) were made from the optic nerve (ON) following unilateral optic tract (OT) transection in adult rats. In response to optic chiasm stimulation CAPs recorded from the ON ipsilateral to the transected OT, i.e., the ON of control side, revealed three positive waves, termed n1, n2, and n3 components, corresponding to fast-, intermediate-, and slow-conducting fibers. Two weeks after OT transection, CAPs recorded from the ON contralateral to the transected OT, i.e., the ON of cut side, were generally smaller in amplitude than those recorded from the ON of control side. The degree of amplitude reduction was different among three components; n3 component was severely reduced and n2 component was moderately reduced, whereas n1 component relatively persisted. These tendencies were more marked in CAPs recorded at 4 weeks after OT transection; n3 component disappeared, whereas n1 and n2 components decreased in amplitude with elongation of latency. Cross sections of the ON after unilateral OT transection were examined electron microscopically, in which significant decrease in fiber density, demyelination, and distorted fibers were verified in the cut side. The present study suggests that slower-conducting ON fibers, that is, smaller-diameter ON fibers are initially and remarkably thrown into retrograde degeneration, while larger-diameter ON fibers are relatively resistant to axotomy.

Action Potentials↗
PubMed1995

Significance of early intra-alveolar fibrotic lesions and integrin expression in lung biopsy specimens from patients with idiopathic pulmonary fibrosis.

To study the pulmonary structural remodeling in idiopathic pulmonary fibrosis (IPF), ultrastructural, immunohistochemical, and light microscopic morphometric observations were made on 11 pulmonary biopsy specimens from patients with IPF. The morphometric study was done using sequentially cut tissue sections stained for keratin-alcian blue periodic acid-Schiff (PAS), fibronectin, and type IV collagen-alcian blue PAS. Most of the early fibrotic lesions, which were alcian blue- and fibronectin-positive, were intra-alveolar in location. Intra-alveolar fibrosis is considered to be essential for the fusion of alveolar walls in IPF. A strong reaction for integrin alpha 5 beta 1 and vinculin was found in epithelial cells and mesenchymal cells in areas of intra-alveolar fibrosis. These findings show that these cells are active in adhesion to fibronectin in areas of early intra-alveolar fibrosis. Some of the epithelial cells, including cytoplasmic hyaline-laden cells, showed evidence of inadequate adhesion to the extracellular matrix, and this may constitute one of the mechanisms of progression of fibrosis in IPF.

Adult↗
PubMed1995

Epitope mapping of monoclonal antibodies to tumor necrosis factor-alpha by synthetic peptide approach.

A monoclonal antibody (mAb) against human tumor necrosis factor-alpha (TNF-alpha), designated 3B10, neutralizes biological activity of TNF-alpha, while another anti-TNF-alpha mAb 10F10 does not. In Western blot analysis, both mAbs bound to SDS-denatured TNF-alpha, indicating that the epitopes recognized by the mAbs are sequential but not conformational. To map precisely the epitopes of the mAbs, 76 overlapping octapeptides corresponding to an entire sequence of TNF-alpha were synthesized and their abilities to react with the mAbs were examined by enzyme-linked immunosorbent assay (ELISA). 3B10 bound to only one peptide at position 81-88 of TNF-alpha, SRIAVSYQ, whereas 10F10 was reactive with three overlapping peptides, ANALLANG (33-40), ALLANGVE (35-42), and LANGVELR (37-44). These results demonstrate that the 81-88 and 37-40 regions are important for the recognition of TNF-alpha by 3B10 and by 10F10, respectively. In solid-phase ELISA, 3B10 inhibited the binding of TNF-alpha to soluble TNF receptors, sTNF-RI and sTNF-RII. In contrast, 10F10 exerted little effect on the binding. TNF-alpha was detected by sandwich-type ELISA where 3B10 alone was used for both capture and detection, suggesting that 3B10 did not interfere with the trimer formation of TNF-alpha. The results obtained in this study suggest that the 81-88 region of TNF-alpha may participate in the receptor binding and that 3B10 neutralizes the activities of TNF-alpha by blocking the region.

Amino Acid Sequence↗
PubMed1995

Monitoring for engraftment following rat orthotopic liver transplantation by in vitro amplification of Y-chromosome gene using polymerase chain reaction.

The polymerase chain reaction (PCR) using primers specific for the rat Y-chromosome gene made it possible to distinguish a very small number of male rat cells from a large excess of female rat cells. In nonimmunosuppressed LEW recipients of ACI liver allografts, the donor cells in the bloodstream disappeared rapidly by day 3, earlier than the biochemical changes indicative of liver dysfunction. In immunosuppressed LEW recipients of ACI liver allografts, the donor cells were detected for a longer time. Moreover, in LEW recipients surviving for long period, the PCR revealed mixed-microchimerism. Our results indicated that this Y chromosomal gene-specific PCR method is useful for assessing engraftment following rat liver transplantation.

Animals↗
PubMed1995

Development of a rat model for orthotopic liver transplantation for hepatocellular carcinoma.

BACKGROUND: Surgical resection is of limited benefit in hepatocellular carcinoma accompanied by severe liver cirrhosis or multicentric hepatic cancer. The long-term survival of patients with advanced hepatocellular carcinoma after transplantation is quite poor. We have studied the characteristics, natural course, and cause of diethylnitrosamine-induced liver cancer in rats and have shown it to be a good model of liver cancer in human beings. Therefore we performed orthotopic liver transplantation (OLT) in rats with diethylnitrosamine-induced liver cancer to study the patterns of recurrence. METHODS: Diethylnitrosamine 100 parts per million in drinking water was administered daily for 4 months to male inbred LEW rats. A laparotomy was performed 120 or 134 days after commencing the oral diethylnitrosamine to confirm the induction of cancer confined grossly to the liver. The livers were resected, and orthotopic transplantation with livers of normal LEW rats was performed. RESULTS: By day 150 all the rats in the non-OLT group died of intraabdominal hemorrhage caused by spontaneous rupture of liver cancer (mean survival time +/- SD, 138.2 +/- 5.3 days; n = 14). However, the OLT (day 120) group recovered their body weight comparatively early after transplantation and survived a maximum of 218 days until death from recurrence (203.8 +/- 21.3 days; n = 4). A significant extension in survival time was observed (p < 0.01). In autopsies performed at the time of death, metastatic liver cancer was observed in the transplanted livers with two showing metastases to the lung. The cause of death was cancer in all the rats. However, the OLT (day 134) group all died of major complications of severe pneumonia and disseminated intravascular coagulation within 2 weeks of OLT (141.3 +/- 5.0 days; n = 4). CONCLUSIONS: After liver transplantation to rats with hepatocellular cancer confined to the liver, recurrence was observed at a comparatively early stage in all transplant recipients. Although a significant prolongation of survival was noted, they all died of cancer. The timing of transplantation is also an important factor. This experimental liver transplantation model of progressive rat liver cancer will be useful in the study of primary liver cancer in human beings.

Animals↗
PubMed1995

Cytotoxicity of anti-c-erbB-2 immunoliposomes containing doxorubicin on human cancer cells.

We have examined the selective cytotoxicity of immunoliposomes containing doxorubicin (chemoimmunoliposomes, CILs) targeting the c-erbB-2 gene product (gp185) or gp125. Anti-gp185 and anti-gp125 CILs were prepared by conjugation of doxorubicin-containing liposomes with monoclonal antibodies SER4 (IgG) and HBJ127 (IgG) respectively. Both CILs bound to human SKBr-3 breast cancer cells and MKN-7 human gastric cancer cells, which express both antigens in high density. The IC50 of anti-gp185 CILs on protein synthesis by SKBr-3 cells was respectively 2- and 25-fold lower than that of anti-gp125 CILs and unmodified liposomes. Furthermore, anti-gp185 CILs significantly inhibited neither the phytohaemagglutin response of normal lymphocytes nor protein synthesis of gp185-negative T24 bladder cancer. Quantitative analysis of cell-associated doxorubicin revealed that, compared with anti-gp125 CILs, anti-gp185 CILs required, respectively 4.5 and 4.3 times less doxorubicin association in SKBR-3 and MKN-7 cells, for 50% cytotoxicity. In addition, flow cytometric analysis showed that both SKBr-3 and MKN-7 internalised more anti-gp185 CILs and processed them more efficiently than anti-gp125 CILs. These results suggest that anti-gp185 CILs act selectively against gp185-expressing cancer cells and that gp185 is a more sensitive antigen for CIL cytotoxicity associated with endocytosis activity.

Animals↗
PubMed1995

Proton pump inhibitors for Helicobacter pylori eradication in patients with peptic ulcer.

We investigated the effects of omeprazole or lansoprazole on peptic ulcer healing, eradication of Helicobacter pylori (Hp) and abdominal symptoms. A prospective, randomized study was performed for the administration of omeprazole or lansoprazole. Hp-positive peptic ulcer patients (n = 86) were randomly assigned to two groups. Gastric ulcer patients received omeprazole 20 mg once daily or lansoprazole 30 mg once daily for 8 weeks. Duodenal ulcer patients were given omeprazole 20 mg once daily or lansoprazole 30 mg once daily for 6 weeks. Endoscopy was performed at baseline, at the end of therapy, and 4 weeks after stopping therapy. The colony factor units (CFUs) of Hp in biopsy specimens were examined. The CFUs of Hp in gastric and duodenal ulcer were significantly decreased at 4 weeks after stopping lansoprazole therapy. We conclude that Hp eradication by combined use of lansoprazole with antibiotics appears to be a promising therapy.

2-Pyridinylmethylsulfinylbenzimidazoles↗