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Biomedical subjects

K Nakatani

Publications and source records attributed to K Nakatani.

At least 19 recordsLinked to original sources
PubMed2006

Milk progesterone profile at and after artificial insemination in repeat-breeding cows: effects on conception rate and embryonic death.

The aim of this study was to investigate whether the skim milk progesterone concentrations at artificial insemination (AI) and day of rise of post-ovulatory progesterone concentration thereafter affect the conception and embryonic death rates in repeat-breeding cows. Milk samples were obtained from 96 repeat-breeding cows that failed to conceive to three or more AIs. The samples were taken from the cows at the day of AI and three times/week until day 45 post-AI. Skim milk was obtained after centrifugation and used for progesterone assay. The cows with a progesterone concentration more than 0.5 ng/ml at AI showed a significantly higher incidence of late embryonic death than those having a progesterone concentration<0.5 ng/ml at AI (p<0.01). As the progesterone level at insemination rose, conception rate declined. A negative correlation was shown between conception rate and skim milk progesterone level at AI. Of 56 cows showing a rise of progesterone to 1 ng/ml or more within 6 days after AI, 28 cows (50%) conceived. On the contrary, only eight of 39 cows (20.5%) conceived when the progesterone rose up to 1 ng/ml after day 6 post-AI. We concluded that increased progesterone concentration at the time of AI and delayed rise of progesterone post-AI might lead to decrease in fertility in repeat-breeding cows.

Animals↗
PubMed2006

Vaginal rhabdomyosarcoma in a dog.

A 10-year-old, female, mongrel showed hemorrhage from vulva. By magnetic resonance image (MRI) and endoscopic examination, a multipapillary mass with a grape-like appearance was found around the urethral opening. Histologically, the mass consisted of variable-sized round-, spindle-to-polygonal-shaped tumor cells including many multinuclear cells. Mitotic figures were also frequently observed. In some areas, that tumor cells were loosely arranged, with intercellular myxoid components. Immunohistochemically, these tumor cells were strongly positive for vimentin and focally positive for desmin but negative for myoglobin. Thus, the case was diagnosed as a relatively poorly differentiated botryoid rhabdomyosarcoma by the macroscopic, histopathologic, and immunohistochemical identification. This is the first report of botryoid rhabdomyosarcoma developing in the vagina of a dog.

Animals↗
PubMed2005

Tubulointerstitial macrophage infiltration in a patient with hypokalemic nephropathy and primary Sjögren's syndrome.

We report a case of hypokalemic nephropathy associated with primary Sjögren's syndrome (SS). The patient presented with profound and persistent hypokalemia secondary to distal renal tubular acidosis (RTA). A renal biopsy exhibited tubular degeneration, marked interstitial fibrosis and intense macrophage infiltration. Hypokalemia has been reported to induce macrophage infiltration in experimental animal models but not in humans. This is the first report of intense tubulointerstitial macrophage infiltration in a patient with hypokalemic nephropathy associated with SS.

Adult↗
PubMed2005

[Papillary fibroelastoma of the right atrium; report of a case].

Papillary fibroelastoma is a rare benign tumor commonly arising from a heart valve. We describe an unusual papillary fibroelastoma that arose from the right side of the interatrial septum. An intracardiac tumor was discovered by routine echocardiography in an asymptomatic 68-year-old woman. The echocardiographic examination revealed a 20 mm mobile tumor in the right atrium. Tricuspid obstruction was not observed, nor was regurgitation. The tumor was resected through a right atriotomy. It had multiple papillary fronds and arose from the interatrial septum. Pathologic examination confirmed papillary fibroelastoma. The postoperative course was uneventful, and the patient was discharged on postoperative day 13.

Aged↗
PubMed2003

Circulating endothelial cells in Kawasaki disease.

Recent reports have demonstrated that circulating endothelial cells (CECs) are observed in several diseases with vascular injury. Because Kawasaki disease (KD) is one type of systemic vasculitis, we hypothesized that an increased number of CECs may be associated with the appearance of complicated coronary artery lesions (CAL). In the present study we investigated the enumeration and origin of CECs in 20 patients with KD, using an immunohistochemical method with monoclonal antibodies: clone P1H12 against ECs and clone AC133 against endothelial progenitor cells (EPCs), which were derived from the bone marrow. The mean number of CECs increased significantly (P < 0.05) from the acute through the subacute phases of KD compared with both the convalescent phase of KD and healthy children. The mean number of CECs was significantly (P < 0.05) higher in six KD patients with CAL than in 14 KD patients without CAL. The population of EPCs in the total CECs in KD was 4.4 +/- 1.2% (range 0-18%). The number of EPCs during the subacute phase was also significantly higher (P < 0.05) in KD patients with CAL than in those without CAL. Our findings indicate that the number of CECs increase in KD vasculitis and suggest that the increased numbers of CECs and EPCs may reflect the EC damage of this disease.

Acute Disease↗
PubMed2003

Pathological significance of oxidative cellular damage in human alcoholic liver disease.

AIMS: To investigate the pathological significance of oxidative stress-induced lipid peroxidation and oxidative DNA damage in alcoholic liver disease. METHODS AND RESULTS: Hepatic expression of 4-hydroxy-2'-nonenal (HNE) adducts and 8-hydroxydeoxyguanosine (8-OHdG) as reliable markers of lipid peroxidation and oxidative DNA damage, respectively, was analysed immunohistochemically and compared with histological findings in alcoholic liver disease. While no HNE adducts were observed in control livers, HNE adducts were frequently (37 of 40 cases, 92.5%) detected in alcoholic liver disease. The localization of HNE adducts was the cytoplasm of hepatocytes and sinusoidal cells in zone 3. As for 8-OHdG, 29 of 40 cases (72.5%) with alcoholic liver disease exhibited positive immunolabelling for 8-OHdG, while 8-OHdG expression was not evident in control livers. The nuclear expression of 8-OHdG was mainly detected in the hepatocytes within the areas of active inflammation. Among histological parameters, the grade of necro-inflammation activity as well as the presence of Mallory bodies were significantly associated with the expression of HNE adducts and 8-OHdG. In addition, the severity of steatosis also correlated with HNE adduct expression. CONCLUSIONS: Lipid peroxidation and oxidative DNA damage occur widely and may be associated with certain pathological features in human alcoholic liver disease.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed2003

Spatial and temporal distribution of "curvina" larvae (Plagioscion squamosissimus Heckel, 1840) and its relationship to some environmental variables in the Upper Paraná River floodplain, Brazil.

With the objective of studying the spatial and temporal distribution of "curvina" Plagioscion squamosissimus larvae and verifying respective spawning sites, monthly sampling was carried out from March 1993 to February 1994 on the Upper Paraná River floodplain. Using a conical-cylindrical plankton net (0.5 mm mesh), samples were taken from the surface of the water bodies, and in the marginal vegetation a strainer and a dragnet ("picaré") were used. Water samples were collected for environmental variable analysis (temperature, dissolved oxygen, water pH, and electrical conductivity). Water level data were obtained from hydrometric stations. High average density of larvae was found from December 1993 to February 1994 due to high temperature and water level. The Baía sub-area was shown to be the most important in the larvae catch, probably due to its semi-lotic characteristics. Larvae size distribution was shown to be more frequent in the 4.0 mm standard length class, indicating that the sampling stations were next to the spawning sites.

Animals↗
PubMed2002

Spatial and temporal distribution of larvae and juveniles of Hoplias aff. malabaricus (Characiformes, Erythrinidae) in the Upper Paraná River floodplain, Brazil.

Spatial and temporal distribution of larvae and juveniles of trahira, Hoplias aff. malabaricus (Erythrinidae), and their relationship with environmental parameters in the Upper Paraná River floodplain were analyzed. Sampling of larvae and juveniles of H. aff. malabaricus has been conducted during the period from November 1991 through February 1995, with 42 sampling stations distributed in four sub-areas: Ivinhema I, Ivinhema II, Baía, and Paraná. During the same period, data were obtained for water temperature, dissolved oxygen, pH, electrical conductivity, river level, precipitation index, and photoperiod. The largest catches of larvae were in the Ivinhema I sub-area (47.06%), and of juveniles in the Paraná sub-area (54.55%). Larvae and juveniles were caught from October to February. Larvae were mainly collected at night and in all types of environments sampled (lotic, semi-lotic, and lentic). Principal Component Analysis of the environmental parameters and larval density showed that the largest catches were obtained in dry season months, with low values for temperature, electrical conductivity, river level, and photoperiod, and with high concentrations of dissolved oxygen and pH. This reproductive strategy may minimizes predation and maximizes food utilization, as it enables the fish to reach advanced developmental stages, while most other species are spawning.

Analysis of Variance↗
PubMed2002

Ultrasonographic evaluation of congenital dislocation of the knee.

The authors describe ultrasonographic findings in a newborn girl with congenital dislocation of the knee (CDK). Ultrasonography showed a hyperechoic area and focal narrowing of the distal quadriceps as compared to the unaffected contralateral side, indicating the presence of fibrosis, which is the main pathologic feature of congenital dislocation of the knee. The hyperechoic area decreased after reduction of the dislocation and with patient growth. Ultrasonography was useful in evaluating CDK because it provided a direct view of the pathologic lesion, was painless, and did not involve exposure to X-rays. Further, we were able to serially evaluate the abnormal findings and provide advice regarding daily activity to the parents of the patient with CDK.

Female↗
PubMed2002

Intravenous immunoglobulin (IVIG) preparations induce apoptosis in TNF-alpha-stimulated endothelial cells via a mitochondria-dependent pathway.

Endothelial cells (ECs) are a target in inflammation, and the death of EC is regulated by various factors. Although intravenous immunoglobulin (IVIG) preparations are known to be beneficial therapeutic agents for the treatment of autoimmune diseases and systemic inflammatory disorders, their mechanism of action have not yet been completely elucidated. The aim of the present study is to investigate the possible role of IVIG in EC apoptosis. We demonstrate herein that IVIG induced the apoptosis of human umbilical vein ECs (HUVECs) prestimulated by TNF-alpha in vitro, but not in unstimulated HUVECs, in a dose- and time-dependent manner, using a proportion of cells with hypodiploid DNA, DNA ladder formation and morphological changes. Anti-Fas MoAbs had no effect on the IVIG-induced apoptosis in the TNF-alpha-stimulated HUVECs. IVIG decreased the intracellular expression of anti-apoptotic proteins of the Bcl-2 family (A1 and Bcl-XL) while IVIG increased the intracellular expression of pro-apoptotic proteins (Bax and Bcl-XS) in the TNF-alpha-stimulated HUVECs. Furthermore, IVIG increased the intracellular production of reactive oxygen species and decreased the mitochondrial membrane potential (Delta(psi)m). Caspase-inhibitors inhibited the IVIG-induced apoptosis of the TNF-alpha-stimulated HUVECs. The present results show a novel action in which IVIG can induce the apoptosis of TNF-alpha-stimulated HUVECs through a mitochondrial apoptotic signalling pathway. These observations suggest that the clinical use of IVIG preparations may thereby regulate the cell death of activated ECs in inflammation.

Apoptosis↗
PubMed2002

Immunohistochemical detection of 8-hydroxydeoxyguanosine, a marker of oxidative DNA damage, in human chronic cholecystitis.

AIMS: Recent studies suggest that oxidative DNA damage induced during chronic inflammation may play a role in carcinogenesis in some organs. Although gallbladder carcinomas are frequently observed with a background of chronic cholecystitis, little is known about oxidative DNA damage in chronic cholecystitis. The aims of this study were to investigate the expression of 8-hydroxydeoxyguanosine (8-OHdG), a biomarker of oxidative DNA damage, in normal and chronically inflamed human gallbladder mucosa and compare its expression with clinicopathological findings. METHODS AND RESULTS: 8-OHdG expression was immunohistochemically examined using a monoclonal antibody against 8-OHdG in human gallbladder specimens. In normal gallbladder (n=5), no 8-OHdG expression was observed. In contrast, nuclear expression of 8-OHdG was detected in 28 of 31cases (90.3%) in gallbladder epithelial cells with chronic cholecystitis. The positive cells were predominantly observed in the areas of active inflammation with prominent cell infiltration. Quantitative analysis revealed that the number of 8-OHdG+ cells (labelling index) significantly (rs=0.671, P < 0.05) correlated with the degree of the activity of mucosal inflammation, while gender, age, and the presence of gallstones did not influence the index. CONCLUSIONS: Oxidative DNA damage is common in chronic cholecystitis, suggesting a possible link between chronic inflammation and gallbladder carcinogenesis.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed2001

Recognition of guanine-guanine mismatches by the dimeric form of 2-amino-1,8-naphthyridine.

Dimeric 2-amino-1,8-naphthyridine selectively binds to a G-G mismatch with high affinity (K(d) = 53 nM). We have investigated a binding mechanism of naphthyridine dimer 2 to a G-G mismatch by spectroscopic studies, thermodynamic analysis, and structure-activity studies for the thermal stabilization of the mismatch. 1H NMR spectra of a complex of 2 with 9-mer duplex d(CATCGGATG)2 containing a G-G mismatch showed that all hydrogens in two naphthyridine rings of 2 were observed upfield compared to those of 2 in a free state. The 2D-NOESY experiments showed that each naphthyridine of 2 binds to a guanine in the G-G mismatch within the pi-stack. In CD spectra, a large conformational change of the G-G mismatch-containing duplex was observed upon complex formation with 2. Isothermal calorimetry titration of 2 binding to the G-G mismatch showed that the stoichiometry for the binding is about 1:1 and that the binding is enthalpy-controlled. It is clarified by structure-activity studies that show (i) the linker connecting two naphthyridine rings was essential for the stabilization of the G-G mismatch, (ii) the binding efficiency was very sensitive to the linker structure, and (iii) the binding of two naphthyridines to each one of two Gs in the G-G mismatch is essential for a strong stabilization. These results strongly supported the intercalation of both naphthyridine rings of 2 into DNA base pairs and the formation of a hydrogen bonded complex with the G-G mismatch.

Base Pair Mismatch↗
PubMed2001

Preconditioning of 3T3 cells by fresh medium together with genistein enhances prostaglandin E(2) release.

Bradykinin induced prostaglandin E(2) release from the Swiss 3T3 fibroblasts, preconditioned with fresh culture medium. Although treatment with genistein for the entire period of preconditioning and incubation with bradykinin attenuated prostaglandin E(2) release, treatment with fresh culture medium and genistein for only the preconditioning period further augmented the prostaglandin E(2) release. In the cells preconditioned with fresh culture medium and genistein, bradykinin caused the phosphorylation of protein tyrosine and mitogen-activated protein kinase/extracellular-regulated kinase (MAPK/ERK), followed by arachidonic acid release. Interestingly, preconditioning with genistein alone also caused phosphorylation and arachidonic acid release, probably reflecting rebound activation after the washout of genistein. However, preconditioning with genistein alone induced neither the augmentation of prostaglandin E(2) release nor the expression of cyclooxygenase-2. The further potentiation of bradykinin-induced prostaglandin E(2) release by combined preconditioning with fresh culture medium and genistein may be due to the activation of the MAPK/ERK-c phospholipase A(2) pathway by preconditioning with genistein.

3T3 Cells↗
PubMed2001

Enhanced second harmonic generation on passing from a mono- to a dicopper(II) bis(salicylaldiminato) schiff base complex.

A new ligand (H2LOH) obtained from the Schiff base condensation of 4-(diethylamino)salicylaldehyde with 1,3-diamino-2-propanol is reported, which yields two different copper(II) complexes: CuLOH and Cu2LO(AcO). Crystal data are as follows. CuLOH*EtOH: monoclinic, P2(1)/n, a = 17.810(2) A, b = 8.515(1) A, c = 18.912(2) A, beta = 112.72(1) degrees, Z = 4. Cu2LO(AcO)*1/2H2O: monoclinic, P2(1)/c, a = 21.407(4) A, b = 15.308(2) A, c = 20.156(3) A, beta = 116.83(2) degrees, Z = 4. Cu2LO(AcO)*1/2H2O is antiferromagnetically coupled with J = -207.7 cm(-1) (J being the parameter of the exchange Hamiltonian H = -J S(A).S(B)). CuLOH and Cu2LO(AcO) exhibit good transparencies in the visible frequency range with absorption maxima at 353 and 372 nm, respectively. An enhancement of 83% of the quadratic hyperpolarizability (beta) is observed by the electric field induced second harmonic (EFISH) technique on passing from the mono- to the dinuclear species. Qualitative ZINDO/SCI quantum-chemical predictions give a satisfactory account for this enhancement. The spin dependence of the NLO response of Cu2LO(AcO)*1/2H2O is found to be negligible within the framework of the DFT theory.

Journal Article↗
PubMed2001

Selective intercalation of charge neutral intercalators into GG and CG steps: implication of HOMO-LUMO interaction for sequence-selective drug intercalation into DNA.

We have synthesized naphthopyranone epoxide 4 from D-isoascorbic acid together with its three diastereoisomers. DNA alkylation of ODNs containing 5'XGT3' and 5'TGY3' by 4 (11R, 13R), where X and Y are any nucleotide bases, occurred at all G residues except at G of the 5'TGC3' sequence. In contrast, the three other diastereoisomers of 4 showed only weak G alkylation activity. Differential (1)H NMR NOE of the 4-G adduct confirmed the G-N7 alkylation at the epoxide carbon of 4 with concomitant S(N)2 ring opening of the epoxide. Quantitative HPLC analysis of G alkylation efficiency for 4 showed the order of G alkylation susceptibility as TGGT approximately CGT >> TGA > AGT > TGT >> TGC. The order was fully consistent with those reported for aflatoxin B(1) oxide and kapurimycin A(3), suggesting that the sequence selectivity observed for these DNA alkylating agents is not structure dependent but most likely due to the intrinsic property of DNA sequences. We found that the order of G alkylation susceptibility obtained for 4 completely matched the calculated HOMO energy level of G-containing sequences. These results underscore that 4 is a unique molecular probe for ranking the HOMO level of G-containing sequences by well-known G alkylation chemistry and suggests that the intercalation of charge neutral intercalators is a HOMO-controlled process.

Base Sequence↗
PubMed2001

Characterization of a stellate cell activation-associated protein (STAP) with peroxidase activity found in rat hepatic stellate cells.

A proteome approach for the molecular analysis of the activation of rat stellate cell, a liver-specific pericyte, led to the discovery of a novel protein named STAP (stellate cell activation-associated protein). We cloned STAP cDNA. STAP is a cytoplasmic protein with molecular weight of 21,496 and shows about 40% amino acid sequence homology with myoglobin. STAP was dramatically induced in in vivo activated stellate cells isolated from fibrotic liver and in stellate cells undergoing in vitro activation during primary culture. This induction was seen together with that of other activation-associated molecules, such as smooth muscle alpha-actin, PDGF receptor-beta, and neural cell adhesion molecule. The expression of STAP protein and mRNA was augmented time dependently in thioacetamide-induced fibrotic liver. Immunoelectron microscopy and proteome analysis detected STAP in stellate cells but not in other hepatic constituent cells. Biochemical characterization of recombinant rat STAP revealed that STAP is a heme protein exhibiting peroxidase activity toward hydrogen peroxide and linoleic acid hydroperoxide. These results indicate that STAP is a novel endogenous peroxidase catabolizing hydrogen peroxide and lipid hydroperoxides, both of which have been reported to trigger stellate cell activation and consequently promote progression of liver fibrosis. STAP could thus play a role as an antifibrotic scavenger of peroxides in the liver.

Amino Acid Sequence↗
PubMed2001

Specific binding of 2-amino-1,8-naphthyridine into a single guanine bulge as evidenced by photooxidation of GG doublet.

Photoirradiation of 2-amino-1,8-naphthyridines in the presence of duplex DNA containing the GG doublet opposite a single bulge was examined. After hot piperidine treatment, DNA cleavage was observed preferentially at the GG opposite a single bulge. The cleavage efficiency was highly dependent on the nature of bulged base. The G cleavage at the GG opposite a single G bulge was exceptionally weak, suggesting an intercalative binding of 2-amino-1,8-naphthyridine chromophore into the GG step.

Base Pair Mismatch↗