Biomedical subjects

K Harada

Publications and source records attributed to K Harada.

At least 415 records · Page 23Linked to original sources

PubMed1997

Neoplastic nodular formation in mouse liver induced by repeated intraperitoneal injections of microcystin-LR.

Neoplastic nodules were observed in mice liver treated with microcystin-LR (MCLR) by the intraperitoneal (i.p.) route over 28 weeks. After 100 i.p. injections of a sublethal dose (20 micrograms/kg) of MCLR, neoplastic nodules were observed without the use of an initiator. Multiple neoplastic nodules up to 5 mm in diameter were observed in the liver of mice in both groups, i.e. those injected 100 times i.p. and those injected 100 times with a 2 month withdrawal. The cysteine conjugate of MCLR was detected mainly in the affected livers. In contrast, when 80 micrograms/kg was orally administered 100 times, characteristic chronic injuries such as fibrous changes and nodule formation were not observed.

Animals↗

PubMed1997

Prognostic significance of serum anti-p53 antibody in patients with hepatocellular carcinoma.

BACKGROUND/AIMS: Abnormalities of the p53 gene can lead to the production of anti-p53 antibody in the serum of cancer patients. We evaluated the prognostic significance of anti-p53 antibody in 86 patients with hepatocellular carcinoma (HCC) in comparison with clinicopathological factors: age, sex, etiology, smoking and drinking habits, history of blood transfusion, presence of encephalopathy and ascites, Child classification, Pugh score, bilirubin, albumin, prothrombin time, indocyanine green retention time at 15 min (ICG), underlying liver disease, alpha-fetoprotein (AFP), tumor size, number of tumors, differentiation degree of HCC, presence of extrahepatic metastasis and therapy for HCC. METHODS: The serum anti-p53 antibody in 86 patients with HCC, 20 with chronic hepatitis (CH) and 20 with liver cirrhosis (LC) was measured by an enzyme-linked immunosorbent assay (ELISA). A single-strand conformation polymorphism-polymerase chain reaction (SSCP-PCR) analysis and loss of heterozygosity (LOH) study of the p53 gene were performed using 8 tissue samples of 8 HCC from four antibody-positive and four antibody-negative patients. The survival probabilities were assessed by the Kaplan-Meier technique, and a Cox regression analysis was used to identify the independent factors for prognosis. RESULTS: Anti-p53 antibody was positive in 32% (28 of 86) of the sera from patients with HCC, but in none of the 20 with CH and 20 with LC. p53 antibody positivity was associated with bilirubin and the number of tumors (p=0.027 and p=0.018, respectively). Overall survival was shorter in the HCC patients with p53 antibody than in those without p53 antibody (p<0.02). Bilirubin, p53 antibody, AFP and ICG were found to be significant prognostic factors by univariate analysis. A Cox multivariate analysis showed that bilirubin and p53 antibody were independent prognostic variables (p<0.0001 and p=0.003, respectively). In four antibody-positive patients, mutation and LOH of the p53 gene were detected in one patient and two patients, respectively. In contrast, only one of four antibody-negative patients exhibited LOH of the p53 gene. CONCLUSIONS: Serum anti-p53 antibody could be a useful prognostic factor in patients with HCC.

Adult↗

PubMed1997

Stability after surgical correction of mandibular prognathism using the sagittal split ramus osteotomy and fixation with poly-L-lactic acid (PLLA) screws.

PURPOSE: This study was designed to examine skeletal stability after surgical correction of mandibular prognathism using a sagittal split ramus osteotomy (SSRO) and fixation with poly-L-lactic acid (PLLA) screws. PATIENTS AND METHODS: Twenty patients with Class III malocclusion were treated with bilateral SSRO and mandibular setback. Ten underwent fixation with titanium screws (group I) and the other 10 with PLLA screws (group II). Cephalograms were obtained 2 or 3 days postoperatively, and at 3, 6, and 12 months after the operation. Changes in the position of upper incisors (U-1), lower incisors (L-1), B-point, and pogonion were examined on lateral cephalograms. RESULTS: Certain tendencies for overjet and overbite were noted to have decreased more markedly, and changes in the position of the skeletal points were greater in group II than in group I. However, statistical analysis showed no significant differences between the two groups. CONCLUSION: Our results suggest that fixation of the bony segments with PLLA screws after SSRO may be used effectively in properly selected cases.

Adolescent↗

PubMed1997

Differentiation of dys- and demyelination using diffusional anisotropy.

We attempted differential diagnosis of dysmyelination and demyelination in childhood using magnetic resonance diffusion weighted imaging. Pelizaeus-Merzbacher disease, one of the dysmyelination disorders, demonstrated diffuse high intensity of the cerebral white matter on T2-weighted images, which demonstrated diffusional anisotropy on diffusion weighted images. On the other hand, high intensity lesions on T2-weighted images in Krabbe disease, one of the demyelination disorders, lost diffusional anisotropy. Another demyelination disorder, Alexander disease-related disorder, also lost its diffusional anisotropy. In contrast to relatively high signal of the lesions on diffusion-weighted images in Krabbe disease (high signal type), the lesions in Alexander disease-related disorder showed low signal on diffusion-weighted images (low signal type). These results suggest that diffusion-weighted images will be clinically useful to differentiate dysmyelination from demyelination; both of them demonstrate similar high intensity lesions of the white matter on T2-weighted images.

Adult↗

PubMed1997

Regional cortical dysplasia associated with suspected hypomelanosis of Ito.

A 15-year-old girl with epilepsy, whose skin lesions were reminiscent of hypomelanosis of Ito, is reported. She manifested hypopigmented linear streaks on her upper and lower limbs. Brain magnetic resonance imaging examinations demonstrated poor differentiation of cerebral gray and white matter of her left occipital lobe, with accompanying gliosis. This region also revealed narrowing of sulci, considered to be mass effect. In this region, almost continuous spike discharges were evident on electroencephalograms, and low-perfusion status was observed on single photon emission computed tomography at rest. She also manifested right lower homonymous quadrant anopsia, which may have its origin in the lesion detected, which appeared to be a migration disorder of neuroblasts in our patient, suggesting that the spectrum of hypomelanosis of Ito might be involved.

Adolescent↗

PubMed1997

Postoperative stability after sagittal split ramus osteotomy with condylar-positioning appliance and screw fixation: asymmetric versus symmetric cases.

OBJECTIVE: The purpose of this study was to evaluate postoperative stability in prognathic patients with mandibular asymmetry who were treated with sagittal split ramus osteotomy of the mandible. STUDY DESIGN: Ten asymmetric (group I) and 11 symmetric (group II) patients were examined. An appliance for repositioning the proximal segment was applied, and the bony segments were fixed with titanium screws. Cephalograms were obtained preoperatively, 2 to 3 days postoperatively, and 3 and 6 months after surgery. Changes in the positions of the standard points were examined on lateral cephalograms, and changes in the widths of the gonion points were examined on posteroanterior cephalograms. RESULTS: Statistical analysis revealed no significant difference between the two groups. In addition, there was no significant difference between the postoperative changes in the widths of the gonion points on the deviated and nondeviated sides in group I. CONCLUSIONS: This study suggests that application of an appliance for repositioning the proximal segment can minimize postoperative skeletal changes in patients with asymmetry.

Adolescent↗

PubMed1997

Kinetic analysis of the covalent binding of captopril to human serum albumin.

A simple and direct method using an N-methylpyridinium polymer-based (4VP-Me) column for the detection of the human serum albumin (HSA)-captopril (Cp) conjugate was developed. By this method, a new peak corresponding to an HSA-Cp conjugate was detected in the serum from a patient receiving Cp. The new peak was composed of a 1:1 molar ratio of Cp and HSA. Time courses of reversible and irreversible binding of Cp to HSA were quite different. The reversible binding decreased rapidly, whereas covalent binding increased gradually. A mechanism is proposed for the formation of the HSA-Cp conjugate and, based on this mechanism, apparent first-order rate constants were calculated. Interestingly, the reactivity in serum was approximately 10-fold higher than that obtained for HSA solutions. The differences in this reaction between serum and HSA solution might be due to the fluctuations in pH as well as the presence of endogenous thiol compounds, oxygen, and metal ions in the solutions.

Angiotensin-Converting Enzyme Inhibitors↗

PubMed1997

Gastric emptying in OLETF rats not expressing CCK-A receptor gene.

We have very recently demonstrated the low acidity of gastric juice and the high susceptibility to the development of gastric ulceration in Otsuka Long-Evans Tokushima Fatty (OLETF) rats not expressing CCK-A receptors. In the present study, gastric emptying in this strain was examined and compared with control Long-Evans Tokushima Otsuka (LETO) rats. Gastric emptying was evaluated by the phenol red method. Gastric emptying 30 and 60 min after a liquid meal in OLETF rats was significantly delayed compared to that in control LETO rats. Intraperitoneal injection of CCK-8 at a dose of 5 microg/kg significantly inhibited gastric emptying in control LETO rats, whereas the same dose of CCK-8 failed to inhibit gastric emptying in OLETF rats. These results suggest for the first time that gastric emptying was suppressed in OLETF rats. We also confirmed with this mutant that CCK delays gastric emptying through the CCK-A receptors.

Animals↗

PubMed1997

Induction of tumour differentiation and apoptosis and LeY antigen expression in treatment with differentiation-inducing agent, vesnarinone, of a patient with salivary adenoid cystic carcinoma.

A patient with locally-advanced submandibular adenoid cystic carcinoma with poorly differentiated solid type, was treated with differentiation-inducing agent, vesnarinone, per os at a dose of 60 mg/day daily for 8 weeks. The vesnarinone administration caused marked regression of the tumour. In addition to conversion into the well-differentiated tubular type from the poorly differentiated solid type, the induction of apoptosis and LeY antigen was observed in the treated tumour. These findings indicate that vesnarinone might be a useful therapeutic agent for treatment of salivary cancer. Since we found the new expression of LeY antigen in the well-differentiated tubular lesion in the salivary adenoid cystic carcinoma treated with vesnarinone, we examined the LeY antigen expression in relation to tumour differentiation in five cases of salivary adenoid cystic carcinoma. Consequently, tissue sections from all of the adenoid cystic carcinoma examined showed no positive LeY staining, except for some areas in the tumour lesion with the tubular pattern including the histologically normal-appearing tissue adjacent to the tumour tissue. These findings suggest that there is the intimate relationship between the LeY antigen expression and tumour differentiation in human salivary adenoid cystic carcinoma.

Journal Article↗

PubMed1997

Therapy for oral squamous cell carcinoma by tegafur and streptococcal agent OK-432 in combination with radiotherapy: association of the therapeutic effect with differentiation and apoptosis in the cancer cells.

Twenty patients with oral squamous cell carcinoma having mainly stage II or III lesions without distant metastasis, were treated with tegafur and streptococcal agent, OK-432, in combination with radiotherapy. As a consequence, 16 cases among the treated 20 cases showed complete remission by this therapy alone. Especially, we have found that the squamous cell carcinoma arising in non-keratinizing oral epithelium rather than in keratinizing oral epithelium has better response to this therapy. Among the 16 cases with complete remission (CR) by the current therapy, 10 cases were histopathologically diagnosed as well-differentiated squamous cell carcinoma and six cases as moderately differentiated squamous cell carcinoma. When we examined immunohistochemically the expression of various antigens such as proliferating cell nuclear antigen (PCNA), p53 and LeY or the presence of DNA fragmentation by nick-end labelling in the biopsy materials taken at the first visit to our clinic from 20 patients treated with the current therapy, the CR group showed a significantly increased LeY expres-sion level ( p< 0.05) and DNA fragmentation rate (p< 0.05) as compared with the partial response (PR, n= 3) + no change (NC, n= 1) group. On the other hand, the CR group with respect to PCNA expression level was significantly decreased as compared with the PR + NC group ( p< 0.05). From these findings, it can be considered that the therapy for oral squamous cell carcinoma by UFT and OK-432 in combination with radiotherapy is very effective, which may be associated with differentiation or apoptosis in oral squamous carcinoma cells. In addition, we present the clinical findings and results of immunohistochemical staining for the biopsy materials obtained from four CR cases treated with the current therapeutic method.

Journal Article↗

PubMed1997

The treatment with differentiation- and apoptosis-inducing agent, vesnarinone, of a patient with oral squamous cell carcinoma.

A patient with histopathological recurrent oral cancer with well-differentiated squamous cell carcinoma, was treated with differentiation- and apoptosis-inducing agent, vesnarinone, per os at a dose of 180 mg/day for 56 days and then at a dose of 60 mg/day for 93 days. The vesnarinone administration caused complete remission of the tumour. It has been found by immunohistochemical staining and PCR-SSCP analysis that the recurrent tumour has wild type p53 gene and relative high level of LeY expression as well as DNA fragmentation in the cancer cells, as assessed by nick-end labelling. These findings suggest that the cure of oral squamous cell carcinoma observed in this case might be associated with induction of differentiation and apoptosis of cancer cells by vesnarinone.

Journal Article↗

PubMed1997

The role of transforming growth factor-beta in PEG-rHuMGDF-induced reversible myelofibrosis in rats.

Pegylated recombinant human megakaryocyte growth and development factor (PEG-rHuMGDF) injected at a suprapharmacologic dose (100 microg/kg) daily for 5 d in normal rats caused marked increases in marrow megakaryocytes and platelet counts at 6-8 d followed by gradual decreases to control levels at 10-20 d. Interestingly, in addition to the expected thrombopoiesis, PEG-rHuMGDF was associated with myelofibrosis with a predominance of reticulin fibres at day 10 followed by complete normalization by day 20. At 6-8 d, the levels of transforming growth factor-beta1 (TGF-beta1) in the extracellular fluid of the marrow, the platelet poor plasma, and the platelet extract were increased 23-, 7- and 2-fold, respectively. The elevated levels of TGF-beta1 were gradually reduced to baseline levels at 13-20 d in accordance with the normalization of myelofibrosis and thrombopoiesis. An ultrastructural analysis showed that large fragments of megakaryocytes were deposited in the marrow parenchyma of PEG-rHuMGDF-treated rats at day 6. PEG-rHuMGDF administration at pharmacologic doses (1 and 10 microg/kg) did not induce the deposition of reticulin fibres in the marrow. These findings suggest that TGF-beta1 leaked from megakaryocytes is involved in the development of the PEG-rHuMGDF-induced myelofibrosis and that this is a reversible process related to the regulation of the excess production of platelets.

Animals↗

PubMed1997

Two-dimensional echocardiographic evaluation of ventricular systolic function in human fetuses with ductal constriction.

Ventricular systolic function was assessed in fetuses, 18 with and 18 without constriction of the ductus arteriosus by serial two-dimensional and Doppler echocardiographic studies. Ductal constriction was defined as maximum systolic velocity of > 140 cm/s and diastolic flow velocity of > 30 cm/s. Ventricular end-diastolic and end-systolic areas were measured from a four-chamber view and area shortening fraction (SF) was calculated: area SF = (area in end-diastole--area in end-systole)/area in end-diastole. In fetuses with ductal constriction, right ventricular end-diastolic and end-systolic areas were significantly increased and right ventricular area SF decreased significantly compared with those values in fetuses without ductal constriction (186 +/- 48 vs. 150 +/- 30 mm2, 112 +/- 34 vs. 81 +/- 19 mm2 and 0.40 +/- 0.05 vs. 0.47 +/- 0.03, respectively, p < 0.01) without any significant changes in left ventricular area SF. Serial studies were available in eight ductal constriction fetuses before and during indomethacin administration, and after withdrawal of the drug for a mean of 24 h. Both systolic and diastolic ductal flow velocities in all fetuses returned to normal range after discontinuation of the drug. During ductal constriction during indomethacin therapy, right ventricular end-diastolic and end-systolic cavity areas were significantly larger and area SF was significantly less than those values before and after the therapy (179 +/- 38 vs. 157 +/- 30 and 154 +/- 27 mm2, 108 +/- 33 vs. 82 +/- 15 and 83 +/- 15 mm2 and 0.40 +/- 0.07 vs. 0.48 +/- 0.03 and 0.46 +/- 0.03, respectively, p < 0.01). This study suggests that ductal constriction influences right ventricular systolic performance.

Blood Flow Velocity↗

PubMed1997

Distribution of ankyrin isoforms and their proteolysis after ischemia and reperfusion in rat brain.

The distribution of brain-type ankyrin (ankyrinB, 212 kDa) and erythrocyte-type ankyrin (ankyrinR, 239 kDa) was investigated in the subcellular fractions of rat forebrain (P1, 1,000 g pellet; P2, 15,000 g pellet; P3, 100,000 g pellet; S, 100,000 g supernatant) by immunoblotting using specific antibodies. The P2 fraction contained approximately 40% of the 212- and 163-kDa isoforms of ankyrinB and the 239-kDa isoform of ankyrinR. Further subfractionation of the P2 by Percoll gradient centrifugation followed by separation of myelin showed association of the three ankyrin isoforms with the synaptosome-rich fraction but not with the myelin-rich fraction. The plasma membrane-rich P3 fraction contained a concentration of ankyrin isoforms similar to that in the P2 fraction. In vitro proteolysis of ankyrin in the P2 fraction with calpain showed that the 212-kDa ankyrinB was more susceptible to calpain than was ankyrinR. In the two-vessel occlusion model, ischemia for 30 min generated the 160-kDa fragment of ankyrinR, and reperfusion for 60 min after 30 min of ischemia remarkably increased the 160-kDa fragment. The reperfusion also significantly decreased the 212-kDa isoform of ankyrinB. Both ischemia-reperfusion and in vitro proteolysis with calpain generated the 160-kDa fragment of ankyrinR, suggesting the involvement of calpain.

Animals↗

PubMed1997

Histopathology of primary biliary cirrhosis with emphasis on expression of adhesion molecules.

In the initiation and progression of immune-mediated destruction of interlobular bile ducts and hepatocytes in primary biliary cirrhosis, T-cell-mediated responses to target antigen(s) expressed on the bile ducts and hepatocytes, as well as cellular adhesions via various adhesion molecules are critical. Intercellular adhesion molecule 1 and, to a lesser degree, vascular adhesion molecule 1 are increasingly expressed on the damaged bile ducts in primary biliary cirrhosis. In addition, lymphocyte function-associated antigens, very late antigens, endothelial-leukocyte adhesion molecule 1, and other adhesion molecules on the vascular endothelial cells and/or inflammatory cells, particularly activated lymphocytes, are also expressed in the portal tracts and hepatic parenchyma. These adhesion molecules are involved in the extravasation as well as epitheliotropic processes of inflammatory cells. Dendritic cells, particularly interdigitating ones in the periductal tissue, are positive for these immune molecules and also for the B-7 family. They may also be important in antigen presentation to CD4+ helper T cells and their activation. However, there is still controversy about whether the B-7 family is expressed on the bile ducts and, then, whether biliary epithelial cells work as an antigen presenting cell. Expression of a very late antigen family on the basolateral surface of bile ducts may be involved in the cell-cell and cell-matrix interactions. Soluble adhesion molecules may be involved in the regulation of immune-mediated bile duct lesions.

Antigen Presentation↗

PubMed1997

Craniocaudal motion velocity in the cervical spinal cord in degenerative disease as shown by MR imaging.

PURPOSE: To investigate, by means of MR phase imaging, the effects of compression on the velocity of craniocaudal motion in the spinal cord. MATERIAL AND METHODS: Spin-echo pulse sequences with velocity encoding gradients were used to examine 12 patients with cervical spondylosis and 6 normal volunteers. Oblique-axial phase images at 3 levels (cranial, middle and caudal), were obtained with prospective electrocardiogram gating. The middle level was set at the site where the spinal cord was most severely compressed, and the cranial and caudal sections were set where it was not compressed. Time-velocity curves were generated at these 3 levels and focal velocity change was correlated with motor function in the lower extremities. RESULTS AND CONCLUSION: The cord showed a higher motion velocity at the compression level than at noncompression levels. This paradoxical increase in velocity was observed in 7 out of 8 patients whose lower extremity motor function was impaired. Four patients with normal lower extremity motor function did not demonstrate this increase in velocity. An increase in motion velocity was therefore found to correlate with impaired lower extremity motor function.

Adult↗

PubMed1997

Role of histidine 46 in the hydrolysis and the reverse transphosphorylation reaction of RNase Rh from Rhizopus niveus.

In order to study the reaction mechanism of RNase Rh from Rhizopus niveus, the rates of cleavage of four 2',3'-cyclic nucleotides by mutant enzymes of RNase Rh, H46F, H109F, E105Q, and K108L were measured. H46F is virtually inactive towards cyclic nucleotides, but H109F hydrolyzed these substrates at 0.7-4.5% of the rates of the native RNase Rh. The other mutants hydrolyzed 2',3'-cyclic nucleotides at 15-20% of the rates of the native enzyme. Relative enzymatic activities towards four cyclic nucleotides of H109F in the hydrolysis reaction (2nd step) were much higher than in the transphosphorylation reaction (the 1st step). In the presence of a 13-fold excess of uridine, H109F catalyzed the transphosphorylation reaction of 2',3'-cyclic AMP (A>p) to ApU. However, this reaction was not catalyzed by H46F mutant or native RNase Rh. These results showed that His46 is crucial to the hydrolysis reaction, and to the reversed reaction of the transphosphorylation reaction. We suggest that His46 in RNase Rh plays a major role in these reactions by acting as a base catalyst to activate water and the 5'-hydroxyl group of nucleosides, respectively.

Binding Sites↗

PubMed1997

Proteolysis of erythrocyte-type and brain-type ankyrins in rat heart after postischemic reperfusion.

Ankyrin links cytoskeleton and integral membrane proteins and is proteolyzed in vitro by calpain, a Ca2+-dependent protease. In the present study, we examined the localization of two ankyrin isoforms, erythrocyte (red blood cell)-type (ankyrin(R)) and brain-type (ankyrin(B)), and their proteolysis after ischemia-reperfusion in the subcellular fractions of perfused rat heart by immunoblotting and by immunohistochemistry using specific antibodies. Both isoforms were observed to be distributed chiefly in the myofibril-nucleus (1,OOOx g pellet: P1) fraction, while ankyrin(R) was located substantially in the membrane (100,000x g pellet: P2) fraction. Reperfusion after 10 min or more of global ischemia induced preferential proteolysis of ankyrin(R) in the P2 fraction and ankyrin(B) in the P1 fraction. The proteolysis of ankyrin(R), but not ankyrin(B), was effectively inhibited by the synthetic calpain inhibitor acethyl-leucyl-leucyl-norleucinal. The immunohistochemical examination showed that anti-ankyrin(R) delineated striations, sarcolemma and nuclei, and the staining was decreased after ischemia-reperfusion, while anti-ankyrin(B) showed diffuse staining. The proteolysis of ankyrin(R) may interfere with force conduction through disruption of the linkage between integral membrane proteins and the myofibril-cytoskeleton.

Animals↗