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Biomedical subjects

K Nakata

Publications and source records attributed to K Nakata.

At least 19 recordsLinked to original sources
PubMed2003

Promotion of corneal epithelial wound healing in diabetic rats by the combination of a substance P-derived peptide (FGLM-NH2) and insulin-like growth factor-1.

AIMS/HYPOTHESIS: The healing of corneal epithelial wounds is often delayed in individuals with diabetes. The effect of the combination of a substance P-derived tetrapeptide (phenylalanine-glycine-leucine-methionine amide, or FGLM-NH(2)) and insulin-like growth factor-1 (IGF-1) on corneal epithelial wound healing was investigated in rats with streptozotocin-induced diabetes. METHODS: The corneal epithelium of diabetic and non-diabetic rats was removed, and the animals were treated by the application of eye drops containing FGLM-NH(2) and IGF-1, or vehicle alone as a control, six times a day for 3 days. The area of the corneal epithelial wound was measured at various times up to 72 h after removal of the corneal epithelium. RESULTS: The rate of corneal epithelial wound healing was slower in diabetic rats treated with vehicle than in non-diabetic rats. However, the rate of wound closure in diabetic rats treated with FGLM-NH(2) and IGF-1 was markedly increased compared with that in diabetic rats treated with vehicle. The wound healing process seemed similar in normal rats and in diabetic rats treated with FGLM-NH(2) and IGF-1. CONCLUSION/INTERPRETATION: The combination of FGLM-NH(2) and IGF-1 promotes corneal epithelial wound healing in diabetic rats, suggesting that such a treatment might prove effective in humans with diabetic keratopathy.

Animals↗
PubMed2003

Nine- or fewer repeat alleles in VNTR polymorphism of the dopamine transporter gene is a strong risk factor for prolonged methamphetamine psychosis.

Susceptibility to drug dependence and drug-induced psychoses is influenced not only by the pharmacological effects of the drug but also by the genetic factors of the individual. To clarify the latter, we investigated the association between methamphetamine (METH) dependence/psychosis and the hDAT1 gene (SLC6A3) encoding the dopamine transporter, which is the primary site of METH activity in the brain. Four exonic polymorphisms of the hDAT1 gene, 242C/T (exon 2), 1342A/G (exon 9), 2319G/A (3'UTR), and VNTR (3'UTR) were examined. Although there was no significant difference in genotypic and allelic distribution of the four polymorphisms between all METH dependence/psychosis patients (N=124) and controls (N=160), the patients with METH psychosis lasting for 1 month or more after discontinuance of METH consumption showed a significant excess of nine- or fewer repeat alleles of the VNTR in 3'UTR of the hDAT1 gene (P=0.0054, OR=4.24, 95% CI=2.46-7.31). The present study demonstrated that the presence of nine- or fewer repeat alleles of hDAT1 is a strong risk factor for a worse prognosis of METH psychosis.

Adult↗
PubMed2003

Relationship of anti-GM-CSF antibody concentration, surfactant protein A and B levels, and serum LDH to pulmonary parameters and response to GM-CSF therapy in patients with idiopathic alveolar proteinosis.

BACKGROUND: Conventional measures of the severity of alveolar proteinosis (AP) include alveolar-arterial oxygen gradient ([A - a]DO(2)), vital capacity (VC), and carbon monoxide transfer factor (TLCO), but alternative serological measures have been sought. Granulocyte-macrophage colony stimulating factor (GM-CSF) neutralising autoantibody is found in patients with idiopathic acquired AP. We have investigated the interrelationships between the levels of this antibody and those of surfactant protein (SP)-A and -B, lactate dehydrogenase (LDH), and conventional measures of disease severity, and the capacity of these parameters to predict the response to rhGM-CSF treatment. METHODS: Blood levels of anti-GM-CSF antibodies, SP-A, SP-B, LDH, and [A - a]DO(2), VC, and TLCO were measured before rhGM-CSF treatment and every 2 weeks thereafter in 14 patients with AP. RESULTS: At baseline, high levels of anti-GM-CSF antibodies and increased SP-A and SP-B levels were seen in all patients, and LDH was raised in 83%. SP-A was highly correlated with [A - a]DO(2), VC, and TLCO (p</=0.02), but other markers were not. Only a normal LDH level was predictive of a response to rhGM-CSF treatment (p=0.03). During treatment a correlation between conventional and serological variables within patients was seen only between SP-A and [A - a]DO(2) (p=0.054), LDH levels and [A - a]DO(2) (p=0.010), and LDH levels and VC (p=0.019). CONCLUSIONS: Of the serological parameters studied, only SP-A and LDH levels were correlated with conventional measures of disease severity, with LDH most accurately reflecting [A - a]DO(2) and vital capacity. Only a normal LDH level predicted a higher likelihood of response to treatment with GM-CSF.

Adolescent↗
PubMed2002

Escherichia coli cells penetrated by chrysotile fibers are transformed to antibiotic resistance by incorporation of exogenous plasmid DNA.

A suspension of recipient Escherichia coli cells in stationary phase, chrysotile asbestos, and pUC18 donor DNA spread over the surface of a Luria-Bertani agar plate using a streak bar several times, resulted in intracellular uptake of the plasmid DNA by the E. coli cells. The transformation efficiency was highest with a duration of cell exposure to chrysotile of more than 60 s and an agar concentration of 2%. To improve chrysotile-mediated transformation efficiency, we systematically optimized various conditions and parameters. In comparison to chrysotile exposure without cations, exposure with cations produced up to 100-fold more transformants. Optimized conditions resulted in 10(6) transformants/ micro g pUC18 DNA. The drastic physical change due to 'quick drying on the surface of the agar plate' when cells were exposed to chrysotile, was essential for chrysotile-mediated transformation. We suggest that DNA uptake mediated by chrysotile asbestos is the result of a mechanical physical transformation of E. coli, since the E. coli cells are not chemically competent. Electron microscopy of cells exposed to chrysotile suggested penetration of the E. coli membrane by chrysotile fibers. It is suggested that E. coli transformation by the plasmid DNA was the result of penetration by chrysotile fibers to which plasmid DNA is bound or adsorbed.

Agar↗
PubMed2002

Tuning of electronic structures of quasi-one-dimensional bromo-bridged Ni(III) complexes with strong electron-correlation by doping of Co(III) ions, [Ni(1-x)Co(x)(Chxn)(2)Br]Br(2).

We have succeeded in synthesizing the Ni(III) complexes doped by Co(III) ions, [Ni(1-x)Co(x)(chxn)(2)Br]Br(2) (x = 0, 0.043, 0.093, and 0.118) by using an electrochemical oxidation method. The single-crystal reflectance spectrum of x = 0.118 shows an intense CT band about 0.5 eV, which is lower than that of [Ni(chxn)(2)Br]Br(2) (1.3 eV). The single-crystal electrical conductivities at room temperature of these compounds increase with increase of the amounts of doping of Co(III) ions. In the ESR spectra, peak-to-peak line widths DeltaH(pp) at room temperature change about 600 G in [Ni(chxn)(2)Br]Br(2) to 200 G in x = 0.118. Such a large x dependence of DeltaH(pp) seems to be ascribed to the increasing contribution from the increasing Curie spins which have smaller line width. Therefore, we have tuned the electronic structures of quasi-one-dimensional bromo-bridged Ni(III) complexes with strong electron correlations by doping of Co(III) ions.

Journal Article↗
PubMed2002

CNR1, central cannabinoid receptor gene, associated with susceptibility to hebephrenic schizophrenia.

To examine the cannabinoid hypothesis for pathogenesis of schizophrenia, we examined two kinds of polymorphisms of the CNR1 gene, which encodes human CB1 receptor, a subclass of central cannabinoid receptors, in schizophrenics and age-matched controls in the Japanese population. Allelic and genotypic distributions of polymorphism 1359G/A at codon 453 in the coding region and AAT triplet repeats in the 3' flanking region in the Japanese population were quite different from those in Caucasians. Although the polymorphism 1359G/A was not associated with schizophrenia, the triplet repeat polymorphism of the CNR1 gene was significantly associated with schizophrenia, especially the hebephrenic subtype (P = 0.0028). Hebephrenic schizophrenia showed significantly increased rate of the 9 repeat allele (P = 0.032, OR = 2.30, 95% CI (1.91-2.69)), and decreased rate of the 17 repeat allele (P = 0.011, OR = 0.208, 95% CI (0.098-0.439)). The present findings indicated that certain alleles or genotypes of the CNR1 gene may confer a susceptibility of schizophrenia, especially of the hebephrenic type.

Adult↗
PubMed2002

Functional changes in rheumatoid fibroblast-like synovial cells through activation of peroxisome proliferator-activated receptor gamma-mediated signalling pathway.

Peroxisome proliferator-activated receptor gamma (PPARgamma) is a ligand dependent transcriptional factor known to be a regulator of adipogenesis. Recent studies have also shown that stimulation of PPARgamma inhibits the transcriptional activities of other nuclear factors and down-regulates proinflammatory cytokine synthesis in T cells and monocytes. We examined, in the present study, the functional significance of PPARgamma expressed in fibroblast-like synovial cells (FLS) isolated from patients with rheumatoid arthritis (RA). Incubation of FLS with a synthetic PPARgamma ligand, troglitazone, inhibited endogenous production of TNF-alpha, IL-6 and IL-8, as well as matrix metalloprotease-3 (MMP-3), without inducing apoptosis of the cells. The gelatinase activity of FLS culture media was also inhibited by troglitazone. Electrophoretic mobility shift assay (EMSA) showed a significant reduction in the DNA binding activity of NF-kappaB in troglitazone-treated FLS in response to TNF-alpha or IL-1beta. Moreover, long-term cultivation of FLS with troglitazone resulted in morphological changes with marked lipid accumulation in these cells. Our results show a negative regulatory function for PPARgamma on cytokine and MMP production together with inhibition of cytokine-mediated inflammatory responses in rheumatoid synovial cells. Our results also suggest that FLS could differentiate into adipocyte-like cells in the presence of proper stimulatory signals including PPARgamma.

Adipocytes↗
PubMed2002

Full-length sequence and functional analysis of hepatitis B virus genome in a virus carrier: a case report suggesting the impact of pre-S and core promoter mutations on the progression of the disease.

In chronic hepatitis B virus (HBV) infection, the quiescent immunotolerant phase evolves into the immunoactive phase. The aim of the present study was to clarify the virological alterations relevant to progression. Serial serum samples obtained from a patient with HBV during long-term follow-up were analysed by sequencing of the full-length HBV-DNA using polymerase chain reaction (PCR). In addition, PCR products of HBV genome from each serum sample were transfected into HuH-7 human hepatoma cells for the functional analysis of the transfected viral genomes. Based on the HBV-DNA sequence analysis, the patient had the genotype C virus, and the mutant HBV with common core promoter mutations (T(1762)A(1764)) and deletion of the pre-S region responsible for large surface protein transcription emerged before the onset of hepatitis. When the vigorous host immune response developed (indicated by the flare-up of hepatitis), the mutant HBV containing common core promoter mutations and another pre-S deletion causing lack of the surface protein promoter became predominant. The HBV-DNA sequences, other than pre-S and core promoter regions were identical to the wild-type sequence throughout the study. Transfection of PCR products containing the mutant HBV sequences resulted in increased amounts of intracellular replicative intermediates but the decreased secretion of HBsAg and HBeAg into culture media, suggesting accumulation of nonenveloped viral core particles within the cells. These results indicate that pre-S deletion and core promoter mutations may participate cooperatively in progression of the disease.

Adult↗
PubMed2002

[Primary malignant tumor of the aorta].

A 63-year old man suffering from bilateral leg pain was admitted to our hospital with an occlusion of the infrarenal abdominal aorta. A bifurcated dacron graft was implanted and a histological examination of the thrombotic material was performed. Atypical cells were detected in the thrombus leading to an investigation of the thoracic aorta showing an unclear mass in the aortic arch. The tumor was resected and the aorta replaced with a dacron graft. Histology revealed a primary sarcoma. The patient is doing well 6 months after operation.

Angiography↗
PubMed2002

Birth of offspring following transplantation of cryopreserved immature testicular pieces and in-vitro microinsemination.

BACKGROUND: Fertility protection is an urgent clinical problem for prepubertal male oncology patients who undergo either chemotherapy or radiotherapy. As these patients do not have mature sperm to be frozen, there is as yet no effective method to preserve their fertility. METHODS AND RESULTS: Single pieces of immature mouse (1.5 x 1.5 x 1.5 mm) or rabbit (2.0 x 2.0 x approximately 3.0 mm) testis were cryopreserved, thawed and transplanted into mouse testes. Histological techniques were used to determine the presence of spermatogenesis, which was restored in both mouse and rabbit testicular pieces, and led to the production of mature sperm after both cryopreservation and syngeneic or xenogeneic transplantation into mouse testes. Using sperm developed in the frozen-thawed transplants, mouse offspring were born after in-vitro microinsemination. Furthermore, rabbit offspring were obtained using rabbit sperm that developed in fresh transplants in a xenogeneic surrogate mouse. CONCLUSIONS: This approach of 'testicular tissue banking' is a promising technique for the preservation of fertility in prepubertal male oncology patients. Xenogeneic transplantation into immunodeficient mice may provide a system for studying spermatogenic failure in infertile men.

Animals↗
PubMed2002

BAL findings in a patient with pulmonary alveolar proteinosis successfully treated with GM-CSF.

BACKGROUND: Idiopathic pulmonary alveolar proteinosis (PAP) has recently been recognised as a disease of impaired alveolar macrophage function caused by neutralising anti-granulocyte-macrophage colony-stimulating (anti-GM-CSF) autoantibodies. Subcutaneous recombinant human GM-CSF is a novel treatment for PAP, but its mechanism of action is unclear. METHODS: Clinical, functional, and bronchoalveolar lavage (BAL) findings were prospectively evaluated in a patient with PAP treated with daily subcutaneous GM-CSF 8 microg/kg for 12 weeks. RESULTS: Treatment resulted in improvements in dyspnoea, lung function, and peak cycle ergometry performance. In serum and BAL fluid the titre of anti-GM-CSF autoantibodies was raised at baseline and markedly reduced on treatment. At baseline the BAL fluid cellular profile showed a decrease in the absolute number and the percentage of macrophages (50%) and an increase in lymphocytes (45%), predominantly CD4+. This cellular distribution remained unchanged after 6 and 12 weeks of treatment while macrophages became morphologically normal and functionally improved. Extracellular proteinaceous material completely disappeared. CONCLUSIONS: Clinically successful treatment of PAP with GM-CSF was associated with a profound reduction in GM-CSF neutralising autoantibodies, improvement in alveolar macrophage morphology and function, but persistent BAL lymphocytosis.

Adult↗
PubMed2001

[Analysis of hematological findings affecting the efficiency of the autologous peripheral blood stem cells harvest].

As a predictor of the timing of peripheral blood stem cell harvest (PBSCH) and the yields of PBSC, the efficacy of measurement of CD34+ cell count in PB has been reported. However this measurement is difficult to carry out on the day of PBSCH in most general hospitals because of not having their own flow cytometry. Therefore in order to evaluate the usefulness of several clinical factors which are easily performed in general hospitals as a guide for PBSCH, we analyzed the correlation between these factors and the harvest efficiency (HE) of PBSCH. Eighty-one PBSCHs mobilized by chemotherapy with granulocyte colony-stimulating factor (G-CSF)(n = 63) or chemotherapy alone (n = 18) were carried out in 33 patients with various malignancies. In the group of PBSCHs mobilized by chemotherapy with G-CSF, a strong correlation was observed between HE and the percentage of immature cells in peripheral WBC (IMA-%) on the harvest day (r = 0.724), and between HE and the count of immature cells in PB (IMA-Co) on the same harvest day (r = 0.629). However routine blood counts, except IMA-% and IMA-Co, and the time (days) required for hemopoietic recovery after mobilizing chemotherapy did not correlate with HE. In the group of PBSCHs mobilized by chemotherapy alone, several hematological findings (WBC count, monocyte count and %, IMA-Co, platelet count, reticulocyte-@1000) on the harvest day and recovering velocity of WBC and platelet correlated with HE. These findings suggested that IMA-% and IMA-Co were the most useful factors for successful PBSCH widely mobilized by chemotherapy with G-CSF in general hospitals.

Antigens, CD34↗
PubMed2001

Retrovirus-mediated gene therapy for hepatocellular carcinoma with reversely oriented therapeutic gene expression regulated by alpha-fetoprotein enhancer/promoter.

In the present study, to achieve more selective and efficient therapeutic gene expression in hepatoma cells, we compared the therapeutic efficacies of the retroviral vectors expressing the herpes simplex virus thymidine kinase (HSV-tk) gene by the alpha-fetoprotein (AFP) enhancer/promoter in the forward (LNAFE0.3TK) and reverse (LN[AFE0.3TK]R) orientation to the vector long terminal repeats. By Northern blotting, the level of the HSV-tk mRNA in LN[AFE0.3TK]R-infected HepG2 human hepatoma cells was much higher than that in LNAFE0.3TK-infected cells. Consistent with this, LN[AFE0.3TK]R infection into HepG2 cells caused a greater cytotoxicity by ganciclovir exposure together with a stronger bystander effect than LNAFE0.3TK infection. In an animal model, intratumorous injection of LN[AFE0.3TK]R with ganciclovir treatment resulted in pronounced growth inhibition of HepG2 tumor. Thus, the reversely oriented therapeutic gene expression under the control of AFP enhancer/promoter is a possible candidate for the retrovirus-mediated gene therapy for hepatocellular carcinoma.

Animals↗
PubMed2001

High-performance liquid chromatographic method to analyze picomole levels of glutathione, cysteine and cysteinylglycine and its application to pre-cancerous rat livers.

A HPLC-based method for quantifying glutathione, cysteine and cysteine-containing peptide is described. N-(2,4-Dinitrophenylaminoethyl)maleimide was synthesized from ethylenediamine, 2,4-dinitrochlorobenzene and maleic anhydride. The maleimide was reacted at 40 degrees C and pH 5.8 for 10 min with thiol compounds such as glutathione or cysteine. An aliquot of the reaction mixtures was applied to a reversed-phase column (4.6 x 150 mm) of HPLC. When glutathione and cysteine were simultaneously assayed, the column was eluted with a gradient of acetonitrile in potassium phosphate (pH 7.0). The derivatives were monitored at 350 nm. Good liner relationships existed between peak area and concentration of glutathione or cysteine from 10 pmol to 2 nmol. The recovery tests from rat liver homogenate were 99.7+/-2.2% for glutathione and 104.9+/-3.8% for cysteine. By this method gamma-glutamylcysteine, cysteinylglycine, and homocysteine could be also quantified. The determination limits of glutathione, cysteine and other thiol compounds were 5 pmol. The method is simple: a sample solution is mixed with the labelling reagent and an aliquot of the reaction mixture is applied to a standard HPLC. The hepatic levels of cysteine and glutathione in pre-cancerous rats were determined by this method. The cysteine level in pre-cancerous livers was extremely elevated in comparison to that of the control groups, while no difference was observed in the glutathione contents between the pre-cancerous and control groups.

Animals↗
PubMed2001

Asymmetric epoxidation with a photoactivated [Ru(salen)] complex.

(Nitrosyl)(salen)ruthenium(II) complex 1 was found to serve as an efficient catalyst for the epoxidation of conjugated olefins under photoirradiation, with 2,6-dichloropyridine N-oxide (2) or tetramethylpyrazine N,N'-dioxide as a stoichiometric oxidant. High enantioselectivity was achieved irrespective of the substitution pattern of olefins. The choice of solvent depends on stability of the resulting epoxides: high enantioselectivity is generally observed in the reaction with ethereal solvents, but use of benzene is recommended when the resulting epoxides are acid-sensitive.

Journal Article↗
PubMed2001

X-linked inhibitor of apoptosis protein (XIAP) inhibits caspase-3 and -7 in distinct modes.

The inhibitor of apoptosis proteins (IAP) regulates cell death by inhibiting caspases. The region of X-linked (X) IAP containing the second baculovirus IAP repeat domain (BIR2) is sufficient for inhibiting caspase-3 and -7. In this study, we found that the modes of inhibition of these two caspases were different: caspase-3 is inhibited in a competitive manner whereas caspase-7 inhibition occurs through a mixed competitive and noncompetitive mechanism. Binding assays revealed that the inhibition of caspase-3 by XIAP was totally dependent on the interaction between the active site of caspase-3 and the linker region between the BIR1 and BIR2 domains of XIAP. In contrast, the active site and the NH(2)-terminal region of caspase-7 bound to the linker region and the BIR2, respectively. Moreover the BIR2 with a mutated linker region, which inhibited caspase-3 very weakly, still bound to and inhibited caspase-7. Furthermore, a chimeric caspase-7/3 comprising the NH(2)-terminal portion of caspase-7 and COOH-terminal portion of caspase-3 was inhibited by XIAP by a mixed competitive and noncompetitive mechanism. Our results suggest that the linker region between BIR1 and BIR2 domains is responsible for active site-directed, competitive inhibition of both caspase-3 and -7, whereas the BIR2 itself is involved in noncompetitive inhibition of caspase-7.

Base Sequence↗