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Biomedical subjects

K Miki

Publications and source records attributed to K Miki.

At least 55 records · Page 3Linked to original sources
PubMed2000

FePer 1, a gene encoding an evolutionarily conserved 1-Cys peroxiredoxin in buckwheat (Fagopyrum esculentum Moench), is expressed in a seed-specific manner and induced during seed germination.

A cDNA corresponding to 1-Cys peroxiredoxin, an evolutionarily conserved thiol-specific antioxidant enzyme, was isolated from buckwheat (Fagopyrum esculentum Moench), a dicotyledonous plant species belonging to the Polygonaceae family. The cDNA, which we have designated as FePer1, contains a major open reading frame capable of encoding a polypeptide of 219 residues with a predicted molecular mass of 24.3kDa. The deduced primary structure of FePer1 polypeptide shows a high level (about 70%) of sequence homology to other recently identified plant 1-Cys peroxiredoxins. FePer1 also exhibits a significant level of sequence similarity to non-plant 1-Cys peroxiredoxins, sharing 52 and 42% identities with mammalian and fungal 1-Cys peroxiredoxins, respectively. As for all 1-Cys peroxiredoxins identified from various organisms, the amino acid sequence proposed to constitute the active site of the enzyme is highly conserved in FePer1 polypeptide. The gene corresponding to FePer1 cDNA is a single-copy gene in the buckwheat genome. Its expression is regulated in a seed-specific and temporal manner during seed development. FePer1 gene is induced transiently for a short period immediately after seed imbibition.

Amino Acid Sequence↗
PubMed2000

Effect of an alternative disulfide bond on the structure, stability, and folding of human lysozyme.

Human lysozyme has four disulfide bonds, one of which, Cys65-Cys81, is included in a long loop of the beta-domain. A cysteine-scanning mutagenesis in which the position of Cys65 was shifted within a continuous segment from positions 61 to 67, with fixed Cys81, has previously shown that only the mutant W64CC65A, which has a nonnative Cys64-Cys81 disulfide, can be correctly folded and secreted by yeast. Here, using the W64CC65A mutant, we investigated the effects of an alternative disulfide bond on the structure, stability, and folding of human lysozyme using circular dichroism (CD) and fluorescence spectroscopy combined with a stopped-flow technique. Although the mutant is expected to have a different main-chain structure from that of the wild-type protein around the loop region, far- and near-UV CD spectra show that the native state of the mutant has tightly packed side chains and secondary structure similar to that of the wild-type. Guanidine hydrochloride-induced equilibrium unfolding transition of the mutant is reversible, showing high stability and cooperativity of folding. In the kinetic folding reaction, both proteins accumulate a similar burst-phase intermediate having pronounced secondary structure within the dead time of the measurement and fold into the native structure by means of a similar folding mechanism. Both the kinetic refolding and unfolding reactions of the mutant protein are faster than those of the wild-type, but the increase in the unfolding rate is larger than that of the refolding rate. The Gibbs' free-energy diagrams obtained from the kinetic analysis suggest that the structure around the loop region in the beta-domain of human lysozyme is formed after the transition state of folding, and thus, the effect of the alternative disulfide bond on the structure, stability, and folding of human lysozyme appears mainly in the native state.

Circular Dichroism↗
PubMed2000

Differential effect of brain-derived neurotrophic factor on high-threshold mechanosensitivity in a rat neuropathic pain model.

We investigated the effect of the systemic infusion of brain derived neurotrophic factor (BDNF) on the behavioral response in a rat neuropathic pain model. One microgram per hour infusion of BDNF significantly attenuated mechanical hyperalgesia tested by the pin-prick test, however, 20 microg/h-BDNF infusion, on the contrary, enhanced the response. Neither 0.5 nor 10 microg/h-BDNF infusion influenced the mechanical hyperalgesia. Mechanical allodynia and thermal hyperalgesia, tested using a von Frey filament (23.0 mN) and the plantar test, were not influenced by BDNF treatment. These data suggest that systemic BDNF treatment can specifically alter high-threshold mechanosensitivity.

Animals↗
PubMed2000

Activating transcription factor 3 (ATF3) induction by axotomy in sensory and motoneurons: A novel neuronal marker of nerve injury.

Activating transcription factor 3 (ATF3), a member of ATF/CREB family of transcription factors, is induced in a variety of stressed tissue. ATF3 regulates transcription by binding to DNA sites as a homodimer or heterodimer with Jun proteins. The purpose of this study was to examine the expression and regulation of ATF3 after axonal injury in neurons in dorsal root ganglia (DRG) and spinal cord. In naive rats, ATF3 was not expressed in the DRG and spinal cord. Following the cut of peripheral nerve, ATF3 was immediately induced in virtually all DRG neurons and motoneurons that were axotomized, and the time course of induction was dependent on the distance between the injury site and the cell body. Double labeling using immunohistochemistry revealed that the population of DRG neurons expressing ATF3 included those expressing c-jun, and in motoneurons ATF3 and c-jun were concurrently expressed after axotomy. In contrast to c-jun, ATF3 was not induced transsynaptically in spinal dorsal horn neurons. We conclude that ATF3 is specifically induced in sensory and motoneurons in the spinal cord following nerve injury and should be regarded as an unique neuronal marker of nerve injury in the nervous system.

Activating Transcription Factor 3↗
PubMed2000

Suppression of neuropeptides' mRNA expression by herbal medicines in a rat model of peripheral inflammation.

The traditional Chinese medicines have been used clinically for a long time in some Asian countries, however, very few studies have been done to demonstrate the working mechanisms of these medicines using recently developed biochemical methodologies. In this study, we examined the anti-inflammatory effect of Huang-Lian-Jie-Du-Tang (HLJDT), a combination of herbs used in traditional Chinese medicine, on paw edema, thermal hyperalgesia and the mRNA increase of neuropeptides in spinal dorsal horn and hypothalamic neurons using a rat model of peripheral inflammation and hyperalgesia. The rats that received HLJDT from 3 days before the injection of complete Freund's adjuvant (CFA) into the plantar had significantly less edema and reduced thermal hyperalgesia compared to control rats that received CFA injection. The up-regulation of preprodynorphin mRNA in L4-5 dorsal horn neurons 8 hours after CFA injection that was observed in control rats, was also decreased in the HLJDT-treated rats. Moreover, there was a significant decrease in mRNA level of corticotropin-releasing factor in the paraventricular hypothalamic nucleus in the HLJDT-treated rats. These data demonstrate that HLJDT is anti-inflammatory, and produces changes in mRNA expression in dorsal horn and hypothalamic neurons. This is the first demonstrated that a traditional Chinese medicine can affect the excitability of neurons through an anti-inflammatory action.

Animals↗
PubMed2000

Disappearance of nodular mesangial lesions in a patient with light chain nephropathy after long-term chemotherapy.

A 64-year-old man developed multiple myeloma (kappa light chain type), nephrotic syndrome, and renal insufficiency in 1993. A renal biopsy showed typical histological findings of light chain nephropathy: nodular glomerulosclerosis with deposition of kappa light chains in the mesangial area and subendothelial space of the glomerular capillary walls. Long-term intermittent MEVP chemotherapy (melphalan, 4 mg/d for 4 days; cyclophosphamide, 100 mg/d for 4 days; vincristine, 1 mg/d; prednisolone, 40 mg/d for 4 days) diminished proteinuria and improved renal function. In April 1999, a follow-up biopsy showed remarkable diminution of nodular lesions and disappearance of kappa light chain deposits. Although the prognosis of light chain nephropathy has been considered poor, long-term successful chemotherapy can clear light chain deposits and restore renal function.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2000

Dorsal column-thalamic pathway is involved in thalamic hyperexcitability following peripheral nerve injury: a lesion study in rats with experimental mononeuropathy.

A total of 68 neurons were recorded from the ventro-postero-lateral nucleus of thalamus (VPL) in rats with a unilateral chronic constriction injury (CCI) of the sciatic nerve (n=20), sham operation (n=24) and naive rats (n=24), and effects of the lesion of dorsal column (DC) pathway [DC lesion or DC+gracile nucleus lesions] on VPL nucleus neuronal activities were studied. In the VPL nucleus contralateral to the CCI (receiving input from the injured nerve), response latencies of low threshold mechanoreceptive (LTM) and wide dynamic range (WDR) neurons to electrical stimulation of the sciatic nerve were significantly longer than that in the contralateral VPL nucleus receiving input from the sham-operated side (P<0.05). In contrast, response latencies of LTM and WDR neurons to DC stimulation were not different between the sham operated and CCI sides (0.05). Background activity of WDR neurons was significantly higher in the VPL nucleus contralateral to the CCI side when compared to neurons in the VPL nucleus contralateral to the sham operated side and in naive animals. Responses of LTM and WDR neurons to innocuous mechanical stimulation of the receptive fields were significantly decreased after DC and DC+gracile nucleus lesions in all animals. However, the responses of WDR neurons to noxious stimuli were selectively reduced only in rats with CCI by DC and DC+gracile nucleus lesions (P<0.05). The decrease in noxious stimulus-evoked responses of WDR neurons in the VPL nucleus contralateral to the CCI side after DC and DC+gracile nucleus lesions was greater than that in the VPL nucleus contralateral to the sham operated side and naive animals. These results indicated that DC and DC+gracile nucleus lesions produced selective and stronger effect on noxious responses of VPL nucleus WDR neurons receiving input from the site of nerve injury. The findings suggest that the gracile nucleus-thalamic pathway conveys, or modulates, nociceptive information to the VPL nucleus following peripheral nerve injury, resulting in an increase in VPL nucleus response to noxious stimuli that contributes to the development of mechanical hyperalgesia.

Animals↗
PubMed2000

Structural genomics projects in Japan.

Two major structural genomics projects exist in Japan. The oldest, the RIKEN Structural Genomics Initiative, has two major goals: to determine bacterial, mammalian, and plant protein structures by X-ray crystallography and NMR spectroscopy and to perform functional analyses with the target proteins. The newest, the structural genomics project at the Biological Information Research Center, focuses on human membrane proteins.

Animals↗
PubMed2000

Survival efficacy of the combination of the methioninase gene and methioninase in a lung cancer orthotopic model.

We have previously demonstrated the antitumor efficacy of recombinant methioninase (rMETase) derived from Pseudomonas putida. To enhance the efficacy of rMETase, we have constructed the pLGFP-METSN retrovirus encoding the P. putida methioninase (MET) gene fused with the green fluorescent protein (GFP) gene. pLGFP-METSN or control vector pLGFPSN was introduced into the human lung cancer cell line H460. The methionine level of H460-GFP-MET cells was reduced to 33% of that of H460-GFP cells. rMETase (0.08 U/mL) in the medium resulted in 10% survival of H460-GFP-MET cells compared with untreated cells in vitro. In contrast, rMETase-treated H460-GFP cells survived at 90% of control. Tissue fragments harvested from subcutaneous tumors of H460-GFP-MET or H460-MET were implanted by surgical orthotopic implantation into the lungs of nude mice. A suboptimal dose of rMETase was administered intraperitoneally daily to mice in each group. Overall survival of rMETase-treated animals with H460-GFP-MET tumors was significantly longer than either rMETase-treated or -untreated animals with H460-GFP tumors (P < .05 in log-rank test). In two repeat experiments, rMETase-treated animals with H460-GFP-MET tumors had a 30-day survival of 80% and 83%, respectively. Untreated animals with H460-GFP-MET tumors had a 30-day survival of 40% and 58%, respectively. rMETase-treated animals with H460-GFP tumors had a 30-day survival of 0% and 33%, respectively. Untreated animals with H460-GFP tumors had a 30-day survival of 0% and 33%, respectively. The retrovirus-mediated gene transfer of METase decreased the intracellular methionine level of tumor cells and consequently enhanced the efficacy of treatment with the rMETase protein. We have thus demonstrated a new strategy of combination tumor therapy with the gene and gene product of MET.

Animals↗
PubMed2000

Relationship between Helicobacter pylori infection and smoking and drinking habits.

BACKGROUND: Helicobacter pylori is a major cause of various gastroduodenal diseases. Some risk factors related to H. pylori infection have been reported; however, studies on the relationship between H. pylori infection and smoking or drinking habits have given conflicting results. In the present study, these relationships were investigated by collecting sera and information from 8837 subjects. METHODS: Serum H. pylori immunoglobulin G antibody was measured by an enzyme-linked immunoassay. In addition to sex and age, information on smoking and drinking habits was collected by questionnaire. Age- and sex-adjusted odds ratios (95% confidence interval) of smoking and alcohol consumption were calculated for H. pylori seropositivity using logistic regression models. RESULTS: Current smokers had a 0.82 (0.74-0.91)-fold greater risk of H. pylori seropositivity than those who had never smoked. Current cigarette consumption showed a dose-dependently negative association with H. pylori seropositivity, and the association between smoking and H. pylori infection was strong in younger subjects. Current drinkers had a 0.88 (0.79-0.98)-fold greater risk of H. pylori seropositivity than those who had never drunk alcohol. The volume of alcohol consumed showed a negative association with H. pylori seropositivity. CONCLUSIONS: In the current study, smoking was negatively associated with H. pylori infection. The risk of H. pylori seropositivity decreased linearly with cigarette consumption per day. Increased gastric acidity in the stomach through smoking may be a cause of the dose-dependently negative association between H. pylori and smoking. Drinking was negatively and dose-dependently associated with H. pylori positivity, although the effect of drinking was weaker than that of smoking.

Adult↗
PubMed2000

Squamous cell carcinoma of the renal pelvis with inferior vena caval extension.

BACKGROUND: We report here on a third case of squamous cell carcinoma (SCC) of the renal pelvis extending to the inferior vena cava. METHODS/RESULTS: A 48-year-old man was diagnosed with an advanced left renal pelvic tumor on computed tomography. He had undergone extracorporeal shock wave lithotripsy for left staghorn calculi 10 years ago. An inferior vena cavagram showed tumor thrombus extending to the inferior vena cava. Percutaneous left renal biopsy revealed SCC. The patient received three courses of combination chemotherapy with cisplatin, bleomycin and etoposide. However, 1 month after the last course of chemotherapy, he died of cancer progress. CONCLUSION: This is the third case of SCC of the renal pelvis extending to the inferior vena cava in the world.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2000

The iteron regions necessary for the RepE-iteron interaction in vivo in mini-F plasmids of Escherichia coli.

We have determined the nucleotide positions of an incC iteron essential for RepE binding by analyzing mutated incC iterons defective in exerting incompatibility towards mini-F plasmids. The mutations affecting this incompatibility occurred mostly at two positions within the incC iteron, i.e. an iteron conserved position and a mini-F specific position. Most of the iterons with a base-change at either of these two positions had lost the binding affinity for RepE. This agrees with the crystallographic structure of the RepE-iteron complex which showed that the N and C terminal domains of RepE interact with the two major grooves on one face of the iteron DNA. These grooves contain the iteron conserved and mini-F specific positions necessary for RepE binding. Thus the binding mode may be common to in the case of mini-F like plasmids.

Bacterial Proteins↗
PubMed2000

Crystallization and preliminary crystallographic analysis of the high-potential iron-sulfur protein from Thermochromatium tepidum.

The high-potential iron-sulfur protein (HiPIP) is an electron carrier between the photosynthetic reaction centre and the cytochrome bc(1) complex in the electron-transfer chain of photosynthesis. The purified HiPIP from Thermochromatium tepidum (formerly Chromatium tepidum) was crystallized in a solution of 1.4 M ammonium sulfate and 0.1 M sodium citrate pH 3.5. The crystals diffract X-rays beyond 1.4 A resolution and belong to the orthorhombic space group P2(1)2(1)2(1), with unit-cell parameters a = 47.12 (6), b = 59.59 (10), c = 23.62 (3) A. The structure was preliminarily solved by the molecular-replacement method. The crystal structure of HiPIP from T. tepidum showed that the proteins exist as monomers, although HiPIPs from several other species can form dimers.

Bacterial Proteins↗
PubMed2000

Preliminary X-ray crystallographic study of DsrD protein from the sulfate-reducing bacterium Desulfovibrio vulgaris.

DsrD (dissimilatory sulfite reductase D) protein encoded by the dsr operon of the sulfate-reducing bacterium Desulfovibrio vulgaris Hildenborough has been crystallized using the vapour-diffusion method with ammonium sulfate as a precipitating agent. The crystals diffract to 1.7 A resolution and belong to the orthorhombic space group P2(1)2(1)2(1), with unit-cell parameters a = 60.54 (6), b = 65. 20 (4), c = 46.41 (3) A. The crystal contains two DsrD molecules per asymmetric unit, giving a Matthews coefficient (V(M)) of 2.6 A(3) Da(-1). A gold-derivative (NaAuCl(4)) crystal has been successfully prepared.

Crystallization↗
PubMed2000

Long-term effect of Helicobacter pylori infection on serum pepsinogens.

Serum pepsinogen values are markers of gastric mucosal status and of gastric cancer risk. The effect of Helicobacter pylori infection and sibship size on change of serum pepsinogen values over a seven-year span was investigated. Data from 2584 subjects with phlebotomy were analyzed both in 1989 and in 1996. The subjects were classified by H. pylori serology and sibship size (1 - 3 vs. 4 and more). Pepsinogen I (PG I) to II (PG II) ratio in '96 minus that in '89 was defined as DeltaPG I / II and compared among the groups. DeltaPG I / II was lower and decrease of PG I / II was more frequent among H. pylori-positive subjects than among negative subjects. The difference was owing to a decrease of PG I in all subjects and owing to an increase of PG II in those not younger than 30 years in '89. In H. pylori-positive subjects, those with a larger sibship size showed lower DeltaPG I / II and higher frequency of PG I / II decline. H. pylori infection exerts a reducing effect on PG I / II during the seven-year span. The effect of H. pylori is stronger among those with a larger sibship size, who are expected to have been infected with H. pylori in childhood. Inducing atrophy of gastric mucosa, which is reflected by a decline of PG I / II, may be one of the mechanisms through which H. pylori elevates the risk of gastric cancer.

Adult↗
PubMed2000

[Analysis of factors influencing the self-regulation of medication and construction of an educational program for patients with chronic hepatic diseases].

The purpose of this study is to construct an educational program for patients with chronic hepatic diseases to avoid self-regulation of medication. We have statistically analyzed the influencing factors of self-regulation from the following 3 viewpoints. First, in the investigation of the number of and the kind of prescribed medicines, it was found that the number of prescribed medicines increased sharply at the stage of Liver Cirrhosis b. Secondly, in the survey of patients' awareness of medication, it was found that self-regulation was influenced by lack of understanding the effects of medicines and the necessity of medication, and by lack of understanding the clinical conditions. Especially, at the stage of Liver Cirrhosis b, self-regulation was strongly influenced by lack of understanding the clinical conditions. Lastly, in the evaluation of patients' characteristics by pharmacists, self-regulation was also strongly influenced by the level of understanding the necessity of medication, understanding the clinical conditions, a patient-doctor relationship, and anxiety about side-effects of medicines. Therefore we have constructed an educational program for patients from the viewpoint of medication. The information consists of two articles; one is the action mechanism of the medicine connected with the clinical conditions to help the patients understand the necessity of medication; the other is how to check the effect and adverse reaction of the medication by themselves to decrease the anxiety about side-effects. Consequently, the medication management and the consultation for inpatients with chronic hepatic diseases were standardized by incorporating the education with the information described above.

Adult↗
PubMed2000

Mechanism for the development of ovarian cysts in patients with congenital lipoid adrenal hyperplasia.

OBJECTIVE: Although ovarian cysts commonly occur in patients with congenital lipoid adrenal hyperplasia (CLAH), the mechanism of development remains to be determined. To clarify the pathogenesis of the ovarian cysts, endocrinological examinations were performed in patients with CLAH. METHODS: The subjects were three Japanese CLAH patients. Basal body temperature, serum and urinary gonadotropin levels, serum and/or urinary ovarian hormones and mutations of the steroidogenic acute regulatory protein (StAR) gene were examined. RESULTS: The basal body temperature was not biphasic in any patient. Basal LH levels were high in all CLAH patients and markedly responded to LH-releasing hormone in two patients. Urinary gonadotropin analysis revealed repetitive LH surges in the menstrual cycles of the CLAH patients. No increase in the urinary pregnanediol suggested anovulation in all patients, and bilateral ovarian cysts were found in two of the subjects. Examination of the StAR gene revealed a frameshift mutation 840delA at codon 238, a nonsense mutation Q258X at codon 258, a homozygotic mutation at Q258X, and a compound heterozygotic mutation with 251insG and Q258X. CONCLUSIONS: We concluded that the development of ovarian cysts may be derived from continued anovulation in CLAH patients. Elevated LH levels may be explained by increased sensitivity of the anterior pituitary to circulating estrogen.

Adolescent↗