Biomedical subjects

N Kawaguchi

Publications and source records attributed to N Kawaguchi.

At least 55 records · Page 3Linked to original sources

PubMed1998

Expression of stromal cell-derived factor-1 and CXCR4 chemokine receptor mRNAs in cultured rat glial and neuronal cells.

The expression of the mRNAs for stromal cell-derived factor-1alpha and -1beta (SDF-1alpha and -1beta) and their receptor CXCR4 in cultured rat glial and neuronal cells was examined. SDF-1alpha mRNA was expressed intensely in astrocytes and weakly in neurons, but not in microglia. SDF-1beta mRNA was expressed weakly in these three types of cells. The expressions of SDF-1alpha and -1beta mRNAs in astrocytes were decreased by treatment with LPS (100 ng/ml) for 1-6 h but markedly increased by that for 24-72 h, whereas the expression of SDF-1beta mRNA in microglia was hardly changed by the treatment for 0.5-6 h, and was decreased by that for 24-48 h. The expression of CXCR4 mRNA was observed in astrocytes, microglia and neurons, and was not altered by LPS treatment.

Animals↗

PubMed1998

Localization of fractalkine and CX3CR1 mRNAs in rat brain: does fractalkine play a role in signaling from neuron to microglia?

Localization of the mRNAs for fractalkine, a CX3C chemokine, and for its receptor CX3CR1 was investigated in the rat brain. In situ hybridization study revealed that fractalkine mRNA was dominantly expressed in neuronal cells particularly in the olfactory bulb, cerebral cortex, hippocampus, caudate putamen and nucleus accumbens. In vitro study using enriched neuronal or glial culture supported the dominant expression of fractalkine mRNA in neurons. On the other hand, CX3CR1 mRNA was dominantly expressed in glial cells throughout the whole brain. The in vitro study suggested the cells expressing CX3CR1 mRNA are microglia, not astrocytes or neurons. Fractalkine appears to function as a signal molecule from neuron to microglia.

Amino Acid Sequence↗

PubMed1998

De novo adipogenesis in mice at the site of injection of basement membrane and basic fibroblast growth factor.

Autografting of fat pads has a long history in plastic and reconstructive surgery for augmentation of lost soft tissue. However, the results are disappointing because of absorption of the grafts with time. The fate of transplanted fat is linked to adipose precursor cells distributed widely in connective tissues. Adipocyte precursor cells can proliferate and mature into adipocytes even in the adult body depending on microenvironment. When reconstituted basement membrane, Matrigel, supplemented with more than 1 ng/ml bFGF was injected s.c. into 6-week-old mice, the neovascularization induced within 1 week was followed by migration of endogenous adipose precursor cells, and a clearly visible fat pad was formed. The pad grew until 3 weeks after the injection and persisted for at least 10 weeks. Such de novo adipogenesis was induced reproducibly by s.c. injection of Matrigel and bFGF over the chest, lateral abdomen, or head. Adipogenesis could be induced even in ear cartilage or in muscle. Thus, our results demonstrated that an abundant population of adipose precursor cells is distributed widely in connective tissues of the adult body and that they migrate into the neovascularized plug of Matrigel for proliferation and maturation. These results suggest a technique of augmenting lost soft tissue in plastic and reconstructive surgery.

Adipocytes↗

PubMed1998

Differences in antigenic sites, recognized by anti-liver-kidney microsome-1 (LKM-1) autoantibody, between HCV-positive and HCV-negative sera in Japanese patients.

Anti-liver-kidney microsome-1 (LKM-1), which reacts with cytochrome P450 IID6 (CYP2D6), is an autoantibody present in autoimmune hepatitis type II, which affects primarily young patients. Recently, it has been shown some adult patients with chronic hepatitis C are also positive for anti-LKM-1. Thus, anti-LKM-1-positive patients can be classified into two subgroups: (1) those with autoimmune hepatitis type II and (2) those with chronic hepatitis C. We investigated the antigenic epitopes of CYP2D6 with which each of these two anti-LKM-1-positive subgroups reacted. Multiple deletion mutants of CYP2D6 were constructed from a human liver cDNA library and five recombinant fusion proteins expressed. Antigenic epitopes were determined by immunoblot analysis using these proteins. Anti-LKM-1 present in HCV-negative sera recognized at least two peptide regions of aa213-280 and aa341-477 of human CYP2D6. In contrast, anti-LKM-1 present in HCV-positive sera recognized only a single region of aa341-477. Thus, the sera of patients with autoimmune hepatitis type II and patients with chronic hepatitis C recognize different antigenic epitopes of the CYP2D6 molecule. To our knowledge, this is the first time LKM-1 autoantigens have been analyzed at the molecular level in Japanese patients.

Asian People↗

PubMed1998

Clinical diagnosis of soft tissue tumors.

In the clinical diagnosis of a soft tissue tumor, it is important to determine whether the lesion is malignant as soon as possible. To establish such a diagnosis we perform aspiration cytology and needle biopsy simultaneously with computed radiography (CR) and echosonogram at the first visit. After the first day's investigations, it is usually possible to select the surgical procedures based on the working diagnosis in almost all patients. When the lesion is clearly benign by diagnosis, excision can be performed. For large lesions or lesions that are suspected to be malignant, CT, magnetic resonance imaging , isotope-investigation, and arteriography are also performed, effectively providing precision in an already established diagnosis. These imaging findings are useful for establishing a surgical plan by anticipating the surgical line of the safety margin. For these few patients in whom the diagnosis still remains uncertain or when preoperative treatment is planned, an incisional or excisional biopsy may be necessary to establish the final diagnosis. When preoperative treatment is performed, the effectiveness of this treatment can be evaluated by medical imaging.

Adipose Tissue↗

PubMed1998

Osteoblastic cells regulate mi gene expression in cultured bone marrow cells.

The microphthalmia (mi) gene encodes a bHLH-Zip protein and certain mutations in this gene are known to result in osteopetrosis. We examined mi gene expression in murine bone marrow (BM) cells and calvaria-derived osteoblastic (OB) cells. The mi message level in BM cells was three- to four-fold higher than that in OB cells. The mi message level in BM cells alone was not enhanced by 1,25(OH)2 vitamin D3 (vitamin D) which induces TRAP-positive multinucleated cells, but was enhanced two-fold by the addition of conditioned medium obtained from cultures of OB cells. The mi message levels in BM cells were also enhanced by macrophage colony-stimulating factor (M-CSF). The mi message levels in cocultures of BM cells and osteoblastic MC3T3-E1 cells, which do not support osteoclastogenesis, were similar to those in the cocultures of BM cells and OB cells. Cocultures of BM cells with MC3T3-E1 cells did not yield TRAP-positive multinucleated cells, but they did maintain osteoclast progenitor cells. These findings suggest that mi is expressed in BM cells that may be under the control of OB cells.

Animals↗

PubMed1998

Association of loss of heterozygosity at the p53 locus with chemoresistance in osteosarcomas.

Although the osteosarcoma is considered to be among the most chemosensitive malignancies and preoperative chemotherapy is commonly applied, an appreciable proportion of cases are in fact quite sensitive. Predictive markers for chemosensitivity are therefore desirable in order to develop effective treatment strategies. Thirty-two cases of conventional osteosarcomas treated at the Cancer Institute Hospital, Tokyo, were analyzed. The sensitivity to preoperative chemotherapy was investigated with reference to loss of heterozygosity (LOH) at the 17p13 (p53) and 13q14 (Rb) loci and expression of the cell-cycle associated proteins, p53, Rb, p21/Waf-1, mdm-2 and Ki-67, as detected immunohistochemically. LOH was detected by analyzing polymerase chain reaction products at marker microsatellite loci. The efficacy of chemotherapy was evaluated both radiologically and histologically. LOH at p53 or Rb loci was seen in 54% (13/24) and 58% (14/24) of cases, respectively. Only 15% of osteosarcomas with LOH at the p53 locus were sensitive to preoperative chemotherapy, as compared to 64% of tumors without such loss (P < 0.05). A similar but much less distinct tendency was observed with LOH at the Rb locus. No relationship was evident between chemosensitivity and immunohistochemical staining patterns for p53, Rb, p21/Waf-1, mdm-2 or Ki-67. The results suggest that p53 gene deletion, but not the other parameters investigated, may be useful for predicting chemoresistance of osteosarcomas.

Adolescent↗

PubMed1998

Detection of a local slow potential preceding the surface QRS complex during non-preexcited impulse propagation--a phenomenon reflecting anterograde concealed conduction through the accessory pathway?

A case of Wolff-Parkinson-White (WPW) syndrome with several interesting electrophysiologic findings is presented. Although manifest preexcitation had not been documented in clinical routine check-ups for the 2 years before the ablation session, an intermittent preexcitation emerged after an initial unsuccessful radiofrequency current delivery directed at the subvalvular mitral annulus 1 cm distal from the subsequent successful ablation site. During intermittent manifestation of preexcitation, the following observations were made: (1) during manifest preexcitation, a possible Kent potential was recorded at the successful ablation site; (2) during non-preexcited impulse propagation, a local slow potential preceding the QRS complex (pre-QRS potential) was clearly observed at the same site; (3) the pre-QRS potential disappeared during orthodromic atrioventricular reciprocating tachycardia, spontaneous atrial premature contraction and after the subsequent successful ablation; and (4) when the pre-QRS potential was obvious, a small change in QRS morphology of the body-surface ECG was appreciable, compared with that during beats of negative pre-QRS potential. A comparable preceding component was also detected in a signal-averaged ECG. It is considered that the pre-QRS potential might be related to the anterograde concealed conduction through the accessory pathway.

Electrophysiology↗

PubMed1997

C-Myc expression and its role in patients with chronic aortic regurgitation.

BACKGROUND: Proto-oncogenes have been implicated in the pathogenesis of gene-mediated myocardial remodeling. In the human heart, however, it has not been clarified whether these proto-oncogenes are related to contractile impairment and structural alteration of the myocardium. The present study is designed to investigate the relationship between the c-Myc protein expression in the myocardium and the myocardial contractile dysfunction in patients with chronic aortic regurgitation who underwent indicated for aortic valve replacement. METHODS AND RESULTS: Twelve patients (11 males and one female) with an average age of 55 years who underwent aortic valve replacement for isolated chronic aortic regurgitation were studied. The preoperative New York Heart Association class was II in four patients and III in eight. Ejection fraction, end-systolic volume index, end-systolic stress (Mirsky's form), and mass index of the left ventricle before surgery were 47+/-13%, 93+/-37 mL/m2, 223.2+/-44.4 Kdyn/cm2, and 210+/-38 g/m2, respectively. A left ventricular endomyocardial biopsy was performed to assess the myocardial cell diameter, fibrous content, and c-Myc protein expression in the myocardium. Cell diameter and fibrous content were significantly higher than those in five normal controls. C-Myc was detected in 9 of 12 present patients but in none of the normal controls. The degree of c-Myc expression had significant positive correlations with ejection fraction (r=0.93; P<.01) and end-systolic stress/end-systolic volume index (r=0.96; P<.01) and significant negative correlations with end-systolic volume index (r=-0.90; P<.01), cell diameter (r=-0.97; P<.01), and fibrous content (r=-0.92; P<.01), which suggested that the degree of c-Myc expression may have a significant negative correlation with myocardial contractility and myocardial hypertrophy. CONCLUSIONS: C-Myc expression may be related to the pathogenesis of myocardial remodeling in patients with chronic aortic regurgitation.

Adult↗

PubMed1997

Expression of activating transcription factor-2 (ATF-2), one of the cyclic AMP response element (CRE) binding proteins, in Alzheimer disease and non-neurological brain tissues.

Cyclic AMP response element (CRE) is a specific DNA sequence which mediates transcriptional activation in the response to the cyclic AMP-activated and protein kinase A dependent signaling pathway. We examined the localization of one of the CRE binding proteins which is preferentially expressed in the brain, activating transcription factor-2 (ATF-2), by immunohistochemistry and Southwestern histochemistry, using the brains of neurologically normal and Alzheimer disease (AD) cases. In all brains, the anti-ATF-2 antibody stained white matter microglial cells. In AD, the cytoplasm of some cortical neurons was also positively stained, but no such staining was seen in the neocortex in non-neurological cases staining. However, both the nuclei and cytoplasm of some hippocampal neurons were positive in non-neurological brain tissues. In AD, except for severely damaged areas such as CA1, positive neuronal staining was seen. Southwestern histochemistry gave the same results as immunohistochemistry. These data suggest that the localization of ATF-2 in cortical neurons in AD may reflect early pathological changes characteristic of AD, and that these histochemistrical methods may allow one to differentiate between healthy and mildly damaged neurons.

Activating Transcription Factor 2↗

PubMed1997

Myocardial histological changes in dilated cardiomyopathy during a long-term left ventricular assist device support.

As the myocardium in patients with dilated cardiomyopathy (DCM) is deteriorating progressively, resulting in a decrease in left ventricular function, patients with end-stage DCM may require implantation of a left ventricular assist device (LVAD) unless they undergo heart transplantation. Although LVAD has been reported to provide excellent hemodynamic support, no data are currently available about the effects of long-term LVAD support on the myocardium in patients with DCM. We describe two patients with end-stage DCM who underwent LVAD implantation and were supported with LVAD for 524 and 245 days, respectively. Serial myocardial biopsies showed increases in myocardial cell diameter and intercellular fibrosis, despite excellent hemodynamic support by LVAD. These data suggest that the myocardium in patients with end-stage DCM deteriorates progressively, even if the pre-load of the left ventricle is reduced by LVAD.

Adult↗

PubMed1997

Chronic hepatitis C associated with anti-liver/kidney microsome-1 antibody is not a subgroup of autoimmune hepatitis.

To determine whether "autoimmune hepatitis type IIb" should be categorized as a subgroup of autoimmune hepatitis, we conducted a clinicopathological study of 25 adult Japanese patients who were positive for anti-liver/kidney microsome-1 (anti-LKM-1) anti-body and infected with the hepatitis C virus (HCV). Anti-LKM-1 was determined by indirect immunofluorescence and by the double immunodiffusion assays we have developed. Twenty-two patients did not present any unusual symptoms or any associated diseases during the course of their chronic HCV infection. The spectrum of HCV genotypes of these patients did not significantly differ from that of anti-LKM-1-negative Japanese patients with chronic hepatitis C. Histological examination of liver biopsy specimens showed the usual characteristics of chronic hepatitis C and lack of characteristics of autoimmune hepatitis type I. No disease-specific HLA haplotypes were noted, and HLA-DR4, which is detectable in 88.7% of Japanese patients with autoimmune hepatitis type I, was detected in only 50.0% of our group, the same rate as the background frequency. Prednisolone was effective in none of the six patients treated, but interferon was effective in six of ten treated patients (60%). From these results, we conclude that "autoimmune hepatitis type IIb" should not be categorized as autoimmune hepatitis, and that this subgroup is essentially chronic hepatitis C in which an autoantibody has been produced during the course of chronic HCV infection.

Adult↗

PubMed1997

Immunocytochemical detection of enhanced expression of c-myc protein in the heart of cardiomyopathic hamster.

An immunocytochemical study was performed to examine the expression of cellular c-myc protein in the heart of 30-, 120- and 180-day-old cardiomyopathic Syrian UM-X7.1 hamsters. The heart of age- and sex-matched BIO-RB hamster was used as normal control. In paraffin sections, an immunostaining for c-myc was markedly increased in cytoplasm of cells from the UM-X7.1 heart as compared with that of the BIO-RB heart which showed a weak staining. However, c-myc was localized in nuclei of cells in frozen sections of the heart. Specific cell types of the heart were differentiated with anti-vimentin, and we found that the increased expression of c-myc was present in nuclei of muscle cells of the UM-X7.1 myocardium. A quantitative study of c-myc-positive nuclei of muscle and nonmuscle cells was carried out by a video micrometer. The mean number of c-myc-positive nuclei of muscle cells was significantly higher in the cardiomyopathic heart than in the control heart from hamsters of all ages studied. These results suggest that the increase of c-myc protein may relate to the pathological state or pathogenesis of the hereditary cardiomyopathy.

Animals↗

PubMed1997

Evaluation of Yucatan micropig skin for use as an in vitro model for skin permeation study.

Skin permeation rates of five non-steroidal anti-inflammatory drugs, three of them lipophilic (ibuprofen, indomethacin and ketoprofen) and two hydrophilic (sodium diclofenac and antipyrine), through Yucatan hairless micropig (YMP) full-thickness skin were determined in vitro using Franz-type diffusion cells, and the usefulness of YMP skin as an animal model skin was investigated. Five-month-old YMP skin showed small variation with respect to drug permeation rates, if the region of skin site was the same. But skin from 6-month-old YMPs showed faster and varied permeation rates due to skin defects. In the case of hydrophilic drugs, no effects on permeation due to the region from which the skin was obtained were observed, although higher permeation rates were observed through the flank than through dorsal skin in the case of ibuprofen and ketoprofen. For YMP skin, the permeation coefficients of drugs were lower than those for hairless rat skin, especially for hydrophilic drugs. Compared with reported human data on permeation coefficients, the permeation coefficients of drugs through YMP skin were 1/2-1/8 of those through human skin, regardless of whether the drugs were hydrophilic or lipophilic. YMP skin could be used as an in vitro animal skin model because of the reproducibility of the permeation rate of drugs through this skin and its similarity to human skin.

Administration, Topical↗

PubMed1997

Curative percutaneous catheter ablation for various supraventricular and ventricular tachyarrhythmias. Results in 187 consecutive patients during the first five years.

Closed-chest transcatheter electrical ablation (catheter ablation) has been applied to various supraventricular and ventricular tachyarrhythmias as a radical therapeutic technique since its introduction in 1982. Currently, it has become a first line therapy for supraventricular tachyarrhythmias except atrial fibrillation and uncommon types of atrial flutter. We first carried out the ablation procedure in 1991 for the treatment of ventricular tachycardia. Up to February 1997, a total of 187 patients underwent catheter ablation in our institution. The aims of this study are to demonstrate our results of catheter ablation in the early 5 years and to show the usefulness of this new curative method. Successful results were obtained in 168 of 187 patients (overall final success rate: 89.8%). The success rates of each category of tachyarrhythmias were 100/105 patients (95%) with WPW syndrome, 41/46 (89%) with atrioventricular nodal reentrant tachycardia, 7/10 (70%) with atrial flutter, 4/4 (100%) with atrial tachycardia, 2/2 (100%) with medically refractory atrial fibrillation, 13/15 (85%) with idiopathic ventricular tachycardia and 3/7 (43%) with sustained ventricular tachycardia associated with structural heart disease, respectively. Complications that required invasive treatments were observed in 3 patients (2 hemopericardium and 1 complete atrioventricular block). Our results indicate that catheter ablation is highly effective in most categories of tachyarrhythmias and can be applied safely without lethal complications.

Adult↗

PubMed1997

[Expression of interferon-alpha mRNA in human brain tissues].

The localization of mRNA of interferon-alpha (IFNA21) was examined in human brain tissues from neurologically normal, Parkinson's and Alzheimer's disease (AD) cases, using an in situ hybridization method. In all cases, signals for the mRNA of IFNA21 were detected in the white matter microglial cells. In AD brains, a few neurons in the parietal lobe were intensely labeled. These results suggest that one type of IFN-alpha protein is constitutively expressed in white matter microglial cells, and that expression of IFN-alpha in neuronal cells may play some role in AD pathology.

Aged↗

PubMed1997

Preservation of pancreatic endocrine function by hemodynamic stabilization following brain death.

A protocol achieving for long-term hemodynamic stability enabled us to evaluate pancreatic endocrine function for up to 1 wk following brain death. The glucose disappearance rate was significantly lower in brain-dead patients (N = 21) than in normal controls (N = 10) (p < 0.001). In 19 brain-dead patients whose plasma epinephrine concentrations exceeded 0.4 ng/ml, the mean early insulin release was significantly lower than in controls, while early insulin release was markedly higher in the remaining two patients. It is possible that early insulin released may be due to increased plasma epinephrine concentrations following brain death. Late insulin release in brain-dead patients was not lower, but was higher than controls and was accompanied by a decrease in the glucose disappearance rate. No evidence of abnormalities in histopathology of pancreas was detected at autopsy. Our results indicate that intrinsic insulin secretory function can be preserved during the first week following brain death.

Adrenergic Agonists↗

PubMed1997

[Establishment of the optimal conditions for detecting anti-M2 by western blotting in primary biliary cirrhosis].

Anti-mitochondrial antibodies(AMA) are serodiagnostic markers for primary biliary cirrhosis(PBC) but heterogenous in antigen molecules which they recognize. A disease-specific AMA for PBC is anti-M2. The conventional examination methods are indirect immunofluorescence and ELISA. However, there are some problems in specificity, because the antigen preparations used are crude. Thus, analysis with Western-blotting(W-B) is needed, because it allows the identification of a molecule which the antibody reacts with. In this report, we established the optimal conditions for detecting anti-M2 with W-B in PBC. As antigen, we used mitochondrial fractions derived from beef hearts. Because a positive band at 74 kDa became negative after absorbing sera with PDH purified from porcine hearts, this band corresponded to major antigeneity of anti-M2. Titration experiments with SDS-PAGE showed that the optimal concentration of this antigen preparation for loading is 0.04 mg/ml. We also performed titration experiments to determine the optimal dilutions for second antibodies and serum samples. The results showed that the optimal dilution for second antibodies, anti-IgG and anti-IgM, were 1:3000 and 1:1000, respectively. The optimal dilution for serum samples was shown to be 1:10(2). Moreover, the W-B technique gave a positive result even for sera from AMA-negative PBC patients which had tested negative with conventional methods, if undiluted sera were examined or if anti-IgG or anti-IgM was used as a second antibody. Thus, the W-B technique is more sensitive than conventional methods of analysis. Based on these results, we will be able to detect anti-M2 with maximum efficiency, thus improving our ability to study the relationship between anti-M2 and the pathological conditions in PBC.

Autoantibodies↗