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Biomedical subjects

M Kondo

Publications and source records attributed to M Kondo.

At least 325 records · Page 18Linked to original sources
PubMed1998

A novel mutation of coproporphyrinogen oxidase (CPO) gene in a Japanese family.

Hereditary coproporphyria (HCP) is an autosomal dominant disease characterized by a deficiency of coproporphyrinogen oxidase (CPO). Only 11 mutations of the gene have been reported to date as the mutations responsible for HCP. We report here a novel mutation of the gene responsible for the disease in a Japanese family. Analysis of the polymerase chain reaction (PCR) amplified DNA fragments of the gene by direct-sequencing and/or cloning-based sequencing methods revealed the gene abnormality responsible for the disease. The mutation found was a single base deletion of T at nt position 526, which results in frame shift and truncation of coded protein at amino acid position 204. Screening of pre-symptomatic cases seemed to be possible by PCR restriction analysis using restriction enzyme Xcm I.

Coproporphyrinogen Oxidase↗
PubMed1998

Focal macular electroretinograms before and after successful macular hole surgery.

PURPOSE: To report changes in focal macular electroretinograms before and after successful macular hole surgery and to discuss whether preoperative retinal function can predict postoperative visual acuity. METHODS: In this prospective study, 28 consecutive eyes of 28 patients underwent vitrectomy for stage 2 or 3 full-thickness idiopathic macular hole. Focal macular electroretinograms using a 4-degree stimulus spot were obtained in 24 eyes of 28 patients, and those using a 5-degree stimulus spot were obtained in 24 eyes of 28 patients, to evaluate preoperative and postoperative amplitude and implicit time of the b-wave. Visual acuity was measured preoperatively and postoperatively, and results were translated into logMAR (minimum angle of resolution) values. RESULTS: After successful macular hole closure, the b-wave amplitude increased in 23 of 24 eyes measured with the 4-degree stimulus spot and in 19 of 24 eyes measured with the 5-degree stimulus spot. Postoperative b-wave amplitude recorded with either stimulus spot correlated with postoperative corrected visual acuity. The b-wave implicit time decreased in 15 of 20 eyes measured with the 4-degree spot and in 13 of 23 eyes measured with the 5-degree spot. Preoperative b-wave implicit time measured with the 5-degree stimulus spot correlated significantly (P = .001) with postoperative corrected visual acuity. CONCLUSIONS: Qualitative change (implicit time) is more important than quantitative change (amplitude) in electroretinograms for predicting postoperative corrected visual acuity. The function of the retinal tissue surrounding the hole may affect visual outcome.

Adult↗
PubMed1998

Vagal afferent projections to lobule VIIa of the rabbit cerebellar vermis related to cardiovascular control.

In decerebrate rabbits we recorded simultaneously field potentials in lobule VIIa of the vermal cerebellar cortex and the vagal compound action potentials (vCAPs) proximally in the vagus nerve following electrical stimulation distally in the same nerve at different intensities. Four principal components of the vCAP were distinguished based on their peak conduction velocities. Their velocities were component I, 67-100 m/s; II, 28-50 m/s; III, 6-28 m/s, IV, 0.4-1.3 m/s. A collision test based on stimulating the recurrent laryngeal nerve identified component I and sub-component IIa of the vCAP as being due to the motor fibres of the descending limb of the nerve. The field potentials evoked in lobule VIIa by electrical stimulation of the cervical vagus nerve were climbing fibre responses as judged by the characteristics of their lamina profile and their response to high frequency stimulation. These field potentials in lobule VIIa correlated most closely with the component III of the vCAP; particularly with a sub-component IIIa of the vagus. Based on the investigations by Evans and Murray (1954) (Histological and functional studies on the fibre composition of the vagus nerve of the rabbit. J. Anat. (Lond.) 88, 320-337) in the rabbit, and by Paintal (1963) (Vagal afferent fibres. Ergeb. Physiol. 52, 74-156) and Mei (1970) (Cardiovascular and respiratory vagal mechanoreceptors in the cat. Exp. Brain Res. 11, 480-501) in the cat, component III is most likely to be due to receptors from the heart and a part of the pulmonary stretch receptors.

Afferent Pathways↗
PubMed1998

Assessment of "microvascular no-reflow phenomenon" using technetium-99m macroaggregated albumin scintigraphy in patients with acute myocardial infarction.

OBJECTIVES: The aim of this study was the scintigraphic evaluation of clinical no-reflow phenomenon. BACKGROUND: In patients with acute myocardial infarction, the relationship of the severity of reduction of microvascular reflow to the ischemia time or to the secondary extension of myocardial necrosis is poorly understood, and we accordingly conducted a scintigraphic evaluation of clinical no-reflow phenomenon. METHODS: The group studied consisted of 25 consecutive patients with their first acute myocardial infarction. After recanalization, each patient received intracoronary injections of technetium-99m macroaggregated albumin (MAA). RESULTS: Eight patients (32%) had absent tracer uptake (scintigraphic no-reflow phenomenon). Fourteen patients showed absent or moderately reduced MAA uptake (group 1) and 11 showed slightly reduced or normal uptake (group 2). The time to recanalization was significantly longer in group 1 than in group 2 (290.4+/-130.6 min vs. 1773+/-93.5 min; p=0.0238). In chronic phase, the thallium-201 (TI-201) defect score index was significantly larger (p < 0.01) and regional ejection fraction was significantly lower (p < 0.01) in group 1 compared with corresponding values in group 2. No significant deterioration from acute phase to chronic phase in either TI-201 defect score index or regional ejection fraction was found in either group (two-way repeated measures analysis of variance). CONCLUSIONS: These findings suggest that scintigraphic noreflow phenomenon occurs in a subgroup of patients without angiographic no-reflow phenomenon, that the myocardial damage depends on the severity of microvascular damage and that prolonged ischemia time may increase the likelihood of "microvascular no-reflow phenomenon."

Aged↗
PubMed1998

Neutrophils, lipid peroxidation, and nitric oxide in gastric reperfusion injury in rats.

Nitric oxide (NO) modulation of ischemia-reperfusion injury was investigated by measuring lipid peroxide and neutrophil accumulation in rat stomachs treated with NG-nitro-L-arginine (L-NNA), a specific NO synthase inhibitor. Ischemia-reperfusion injury was induced in the rat stomach. Treatment with L-NNA for 3 days at a dose of 3 mg/kg/day significantly enhanced this injury. This enhancement was reversed by the simultaneous administration of L-arginine at a dose of 30 mg/kg/day. Both thiobarbituric acid (TBA)-reactive substances, an index of lipid peroxidation, and myeloperoxidase (MPO) activity, an index of tissue-associated neutrophil accumulation, were increased in the gastric mucosa after ischemia-reperfusion. L-NNA treatment enhanced these increases in TBA-reactive substances and MPO activity. The increase in the area of gastric erosions correlated closely with accumulation of TBA-reactive substances as well as the increase in MPO activity. Enhancement of ischemia-reperfusion injury by L-NNA treatment was inhibited by injection with anti-neutrophil antibody, anti-platelet activating factor (PAF) antagonist, and anti-leukotriene B4 (LTB4) receptor antagonist. In addition, the increase in TBA-reactive substances and MPO activity was decreased by these antibodies or antagonists. Enhancement of reperfusion-induced gastric mucosal injury associated with inhibition of NO synthesis may involve neutrophil infiltration and lipid peroxide accumulation in the gastric mucosa, mediated by PAF and LTB4.

Animals↗
PubMed1998

Dried green leaf powders of Jew's mellow (Corchorus), persimmon (Diosphyros kaki) and sweet potato (Ipomoea batatas poir) lower hepatic cholesterol concentration and increase fecal bile acid excretion in rats fed a cholesterol-free diet.

A cholesterol-free diet containing dried powder of Jew's mellow leaves, persimmon leaves or sweet potato leaves respectively at 5% level as dietary fiber was fed to male Sprague-Dawley rats for about one month. The experiment was conducted twice except for sweet potato leaves. In the groups fed the diet mixed with powders of any of the three different dried green leaves, the hepatic cholesterol concentration significantly decreased. Such lowering was not observed in serum cholesterol concentration compared with the control (cellulose) group. A significant increase in fecal weight was observed in all the groups fed the green leaf samples. All the dried green leaves increased fecal excretion of bile acids per gram or per day compared with the control group in both experiments, but only the dried Jew's mellow leaves showed an increased excretion of neutral sterols. These results suggest that lowering of hepatic cholesterol by powdered green leaves is not necessarily due to the same factor, but to the increased fecal excretion of bile acids due to inhibited enterohepatic circulation in animals given these samples.

Animals↗
PubMed1998

Role of active oxygen species and lipid peroxidation in mepirizole-induced duodenal ulcers in rats.

The role of active oxygen species and lipid peroxidation in the pathogenesis of duodenal ulcers induced by mepirizole was investigated in rats. Oral administration of mepirizole (200 mg/kg) resulted in ulcer lesions in the proximal duodenum. Thiobarbituric acid-reactive substances (TBA-reactive substances), an indicator of lipid peroxidation, also significantly increased in the duodenal mucosa. Myeloperoxidase (MPO) activity in the duodenal mucosa, a sign of polymorphonuclear leukocyte (PMN) accumulation, significantly increased. Combination treatment with polyethylene glycol-modified Serratia Mn-SOD and catalase significantly decreased the size of the ulcers and TBA-reactive substances in the duodenal mucosa. Allopurinol, a xanthine oxidase inhibitor, also reduced the size of duodenal ulcers. Both the size of the ulcers and the increase in TBA-reactive substances in the duodenal mucosa were significantly lower in PMN-depleted rats. Mepirizole increased the surface expression of adhesion molecule CD18 on PMNs in vitro. These results suggest that lipid peroxidation, mediated by active oxygen species generated from xanthine oxidase and PMNs, plays an important role in the pathogenesis of duodenal ulcers induced by mepirizole.

Allopurinol↗
PubMed1998

HLA-DRB1 alleles contribute to determining the prognosis of Japanese diabetes mellitus positive for antibodies to glutamate decarboxylase.

Diabetes mellitus positive for antibodies to glutamate decarboxylase is heterogeneous as far as the degree of impairment of endogenous insulin release, though antibodies to glutamate decarboxylase are the most useful marker for future insulin deficiency. To investigate what determines the prognosis of diabetes mellitus positive for antibodies to glutamate decarboxylase, we measured HLA-DRB1 alleles in three groups: 77 cases of insulin-dependent diabetes mellitus (IDDM), 44 of non-insulin-dependent diabetes mellitus (NIDDM) with secondary failure of oral hypoglycemic therapy, and 22 of NIDDM well controlled by diet and/or sulfonylurea agents. The proportion of susceptible and resistant alleles to IDDM determined the degree of insulin deficiency, and comparison of IDDM to NIDDM well controlled by diet and/or sulfonylurea agents revealed significant differences in DRB1*0405 (P < 0.05; RR = 2.82 and RR = 0.89, respectively) and DRB1*1502 (P < 0.001; RR = 0.02 and RR = 2.19, respectively). This study revealed that HLA-DRB1 alleles contribute to determining the prognosis of Japanese diabetes mellitus positive for antibodies to glutamate decarboxylase.

Adolescent↗
PubMed1998

Selection system for genes encoding nuclear-targeted proteins.

Nuclear proteins have essential roles in cell proliferation and differentiation. We have developed a yeast selection system-the nuclear transportation trap (NTT)-to identify genes encoding nuclear transport signals. Both unknown and previously identified nuclear localization signals were identified from a human fetal brain cDNA library. The majority (75%) of the unknown proteins examined were exclusively localized to the nucleus in COS-7 cells. We propose that NTT is an efficient method for isolating cDNAs that encode nuclear targeted proteins that can be applied to the retrieval of novel nuclear proteins and to annotate gene function.

Amino Acid Sequence↗
PubMed1998

p53 mutations in non-small-cell lung cancers occurring in individuals without a past history of active smoking.

Accumulating evidence suggests that the p53 gene is a good target for molecular epidemiological studies. We previously reported an association between the presence of p53 mutations and lifetime cigarette consumption. Although over 675 p53 mutations have been reported in lung cancers in the literature thus far, very little is known about the nature of such changes in lung cancers in the absence of a smoking background. In the present study, we therefore analysed 69 non-small-cell lung cancer specimens from individuals without any history of active smoking and identified p53 mutations in 26% of the cases. Statistical analysis of the present cohort of non-smokers also showed absence of significant relationship between p53 mutations and age, sex, histological type or disease stage. Comparison of mutational spectra between the present results in non-smokers and previously reported mutations in smokers clearly demonstrated G:C to T:A transversions to be significantly less frequent in non-smokers than in smokers (OR 5.35, 95% CI 1.77-16.12). Interestingly, G:C to C:G and G:C to A:T mutations were also observed in tumours of non-smokers at similar frequencies to G:C to T:A mutations, suggesting that these mutations can occur relatively frequently in the absence of active smoking. This study is, to our knowledge, the largest so far analysing a well-defined cohort of non-smokers in a single laboratory.

Adult↗
PubMed1998

Hemolytic uremic syndrome after allogeneic or autologous hematopoietic stem cell transplantation for childhood malignancies.

Of 193 children who underwent hematopoietic stem cell transplantation (HSCT) for various malignancies, 10 developed hemolytic uremic syndrome (HUS) 1 1/2-5 months later. All 10 had microangiopathic hemolytic anemia, thrombocytopenia and impaired renal function. Six of 10 presented with pericardial effusion, while three presented with hypertension. No child required plasma exchange, and all patients have survived without life-threatening long-term sequelae. By univariate analysis, the underlying diagnosis of neuroblastoma and a history of cisplatin (CDDP) administration were significantly associated with the development of HUS (P < 0.0001). By multivariate analysis using logistic regression, neuroblastoma and use of total body irradiation (TBI) as a conditioning regimen were significant contributing factors for HUS (P = 0.0001 and 0.036, respectively). Although CDDP administration could not be evaluated because of its strong correlation with the underlying diagnosis, we speculate that CDDP may enhance the nephrotoxicity of TBI, leading to a high incidence of HUS in patients with neuroblastoma.

Adolescent↗
PubMed1998

Late-onset hemorrhagic cystitis after hematopoietic stem cell transplantation in children.

We analyzed the incidence, complications, and risk factors for late-onset hemorrhagic cystitis (HC) in 256 children undergoing hematopoietic stem cell transplantation (HSCT). Twenty-six recipients (10.2%) developed late-onset HC between 3 and 270 days (median, 33 days) after HSCT. In most patients, the severity of HC was mild to moderate, and spontaneous resolution occurred. Three children developed bladder tamponade, and one required suprapubic cystotomy. Four children died in the early post-transplant period without resolution of HC, but HC was not the direct cause of death in any patient. Twenty-two patients recovered within 6-86 days (median, 16 days) of onset. Three predisposing factors were identified for development of late-onset HC by multivariate analysis: allogeneic HSCT, older age (> or = 7 years), and busulphan for pretransplant conditioning were significantly associated with late-onset HC (P=0.022, P=0.044 and P=0.036, respectively). Excretion of adenovirus type 11 was demonstrated in six of 22 patients at the onset of cystitis. We suspect that reactivation of virus may be a major pathogenic factor in late-onset HC, but several clinical factors are also associated.

Adolescent↗
PubMed1998

R411C mutation of the ALAS2 gene encodes a pyridoxine-responsive enzyme with low activity.

A R411C missense mutation of the erythroid-specific delta-aminolaevulinate synthase (ALAS2) gene was identified in a pedigree with X-linked pyridoxine-responsive sideroblastic anaemia (XLSA). The normal and the mutant cDNAs were expressed in E. coli, and the enzyme protein was purified. ALAS activity of the mutant enzyme was 12% and 25%, when incubated in the absence and the presence of pyridoxal 5'-phosphate, respectively, compared with that of the wild-type enzyme. These findings suggest that the R411C mutation accounts for low ALAS activity and a partial pyridoxine-responsiveness of the disease in the patient.

5-Aminolevulinate Synthetase↗
PubMed1998

Range of motion of the temporomandibular joint in rheumatoid arthritis: relationship to the severity of disease.

The purpose of this study was to determine the frequency and nature of temporomandibular joint (TMJ) involvement in rheumatoid arthritis (RA) patients with symptoms in this joint, and to investigate the relationship of symptoms to the C-reactive protein (CRP), erythrocyte sedimentation rate (ESR) and Steinbrocker stage. Clinical examination of the range of motion of the TMJ was performed in 218 RA patients. In addition, correlations between the maximal mouth opening and the severity of RA were studied. Restriction in opening the mouth (defined as < or = 30 mm movement in the central incisor region from the fully occluded to maximally open positions) was observed in 12.8% of the RA patients (28/218). The CRP, ESR and Steinbrocker stage were all correlated with maximal opening (p < 0.05). There was a positive correlation between the severity of RA and the range of motion of the jaw.

Adult↗
PubMed1998

Monitoring of human cytomegalovirus infections in pediatric bone marrow transplant recipients by nucleic acid sequence-based amplification.

In the diagnosis of human cytomegalovirus (HCMV) infection, it is very important to distinguish symptomatic from asymptomatic infection. The nucleic acid sequence-based amplification (NASBA) technique was compared with single and nested polymerase chainreaction (PCR) methods. For NASBA detection, the beta2.7 transcript was chosen as a target because of its abundant active HCMV-specific expression. Of 20 pediatric bone marrow transplant (BMT) recipients, 8 developed HCMV-related clinical symptoms. The clinical sensitivities and specificities were 50% and 100% for single PCR, 100% and 67% for nested PCR, and 100% and 83% for NASBA, respectively. Follow-up of HCMV infections in pediatric BMT recipients showed that NASBA could both detect viral transcript prior to the onset of clinical symptoms and reflect clinical improvement due to antiviral therapy. These data suggest that NASBA should be useful for both predicting HCMV disease development and monitoring the effect of antiviral therapy.

Adolescent↗
PubMed1998

Interaction and orientation of an alpha-aminoisobutyric acid- and tryptophan-containing short helical peptide pore-former in phospholipid vesicles, as revealed by fluorescence spectroscopy.

The interaction and orientation of a membrane protein ion channel model, an alpha-aminoisobutyric acid analogue of gramicidin B (GBA), in egg yolk phosphatidylcholine vesicles was studied by means of fluorescence spectroscopic techniques. GBA helices form stable ion-conducting pores in membranes [Jelokhani-Niaraki et al. (1995) J. Chem. Soc. Perkin Trans. 2, 801-808]. In an alpha-helical model for the peptide, all Trp residues (intrinsic fluorophores) are distributed near the C-terminus. Fluorescence quenching experiments revealed the exposure of the helical peptides' C-termini to aqueous environments. Dansyl-labeled vesicles were used to investigate the GBA dynamism of the interaction with membranes. It was shown that considerable amounts of peptide reside on and in the vicinity of the outer surface of lipid bilayers. The transmembrane transfer to the inner layer is slow due to the high affinity of Trp residues for bilayer interfaces which anchor the peptide to the outer surface. A structural-functional interpretation of the GBA interaction with membranes is presented.

Gramicidin↗
PubMed1998

Glyoxysomal malate dehydrogenase in pumpkin: cloning of a cDNA and functional analysis of its presequence.

Glyoxysomal malate dehydrogenase (gMDH) is an enzyme of the glyoxylate cycle that participates in degradation of storage oil. We have cloned a cDNA for gMDH from etiolated pumpkin cotyledons that encodes a polypeptide consisting of 356 amino acid residues. The nucleotide and N-terminal amino acid sequences revealed that gMDH is synthesized as a precursor with an N-terminal extrapeptide. The N-terminal presequence of 36 amino acid residues contains two regions homologous to those of other microbody proteins, which are also synthesized as large precursors. To investigate the functions of the N-terminal presequence of gMDH, we generated transgenic Arabidopsis that expressed a chimeric protein consisting of beta-glucuronidase and the N-terminal region of gMDH. Immunological and immunocytochemical studies revealed that the chimeric protein was imported into microbodies such as glyoxysomes and leaf peroxisomes and was then subsequently processed. Site-directed mutagenesis studies showed that the conserved amino acids in the N-terminal presequence, Arg-10 and His-17, function as recognition sites for the targeting to plant microbodies, and Cys-36 in the presequence is responsible for its processing. These results correspond to those from the analyses of glyoxysomal citrate synthase (gCS), which was also synthesized as a large precursor, suggesting that common mechanisms that can recognize the targeting or the processing of gMDH and gCS function in higher plant cells.

Amino Acid Sequence↗