Search PubMed⌕ Search

Biomedical subjects

N Shimoda

Publications and source records attributed to N Shimoda.

At least 37 records · Page 2Linked to original sources
PubMed1999

Short inverted-repeat transposable elements in teleost fish and implications for a mechanism of their amplification.

Angel is the first miniature inverted-repeat transposable element (MITE) isolated from fish. Angel elements are imperfect palindromes with the potential to form stem-loop structures in vitro. Despite sequence divergence of elements of up to 55% within and between species, their inverted repeat structures have been maintained, implying functional importance. We estimate that there are about 10(3)-10(4) Angels scattered throughout the zebrafish genome, evidence that this family of transposable elements has been significantly amplified over the course of evolution. Angel elements and Xenopus MITEs carry common sequence motifs at their termini, indicating common origin and/or related mechanisms of transposition. We present a model in which MITEs take advantage of the basic cellular mechanism of DNA replication for their amplification, which is dependent on the characteristic inverted repeat structures of these elements. We propose that MITEs are genomic parasites that transpose via a DNA intermediate, which forms by a folding-back of a single strand of DNA, that borrow all of the necessary factors for their amplification from products encoded in the genomes in which they reside. DNA polymorphisms in different lines of zebrafish were detected by PCR using Angel-specific primers, indicating that such elements, combined with other transposons in vertebrate genomes, will be useful molecular tools for genome mapping and genetic analyses of mutations.

Animals↗
PubMed1999

Circulating prostate-specific antigen mRNA during radical prostatectomy in patients with localized prostate cancer: with special reference to neoadjuvant hormonal therapy.

To determine the potential risk of hematogenous dissemination of prostate cancer cells during radical prostatectomy (RP), we investigated the pre- and intraoperative circulating prostate-specific antigen (PSA) mRNA in patients with clinically localized prostate cancer, with special reference to neoadjuvant hormonal therapy (NHT). Using a nested reverse transcriptase (RT) polymerase reaction (PCR) assay, PSA mRNA in the peripheral blood was evaluated pre- and postoperatively in a total of 23 patients, 10 of whom received NHT with antiandrogens. The RT-PCR assay employed detected one LNCaP cell in 10(7) mononuclear blood cells, and showed no positive signal in the blood samples from all 15 healthy controls. Pre- and intraoperative circulating PSA mRNA was positive in 11 (48%) and 18 patients (78%), respectively. All 11 patients with positive preoperative PSA mRNA continued to be positive during RP, and seven (58%) of 12 patients with negative preoperative PSA mRNA had a positive conversion. Although the patients' ages, preoperative serum PSA values and clinical or pathological stages were not associated with the pre- and intraoperative PSA mRNA results, the NHT group showed a significantly lower incidence of preoperative PSA mRNA positivity (2/10) than the group receiving RP alone (9/13) (20% vs 69%, P = 0.036). NHT, however, showed no suppressive effect on either intraoperative positivity or positive conversion of circulating PSA mRNA. The present study suggests that a substantial number of patients receiving RP are at risk of hematogenous dissemination, and NHT with antiandrogens has a minimal or no suppressive effect on the circulating PSA mRNA during surgical manipulation of the prostate. Because the clinical significance of circulating cancer cells remains to be determined, long-term follow-up in association with the circulating cancer cells assessed by the RT-PCR is essential in order to establish the role of molecular staging as well as NHT.

Aged↗
PubMed1999

Increased serum levels of vascular endothelial growth factor in patients with renal cell carcinoma.

Neovascularization, an essential event for the growth of solid tumors, is regulated by a number of angiogenic factors. One such factor, vascular endothelial growth factor (VEGF), is considered to exert a potent angiogenic activity, as indicated by immunohistochemical and molecular evidence. In this study we investigated the serum VEGF level (s-VEGF) in patients with renal cell carcinoma (RCC). s-VEGF in peripheral blood samples was analyzed in 40 RCC patients and 40 patients without cancer (controls) using a sandwich enzyme-linked immunoassay. In 20 RCC patients, serum samples were obtained separately from the bilateral renal veins. s-VEGF was also measured before, 4 and 8 weeks after nephrectomy in 11 patients. There were significant differences in s-VEGF between the RCC patients and the controls (207.3+/-32.9 vs. 71.5+/-9.1 pg/ml, mean+/-SE) (P<0.005), between the tumor-bearing renal veins and the contralateral ones (P<0.01), between the pre- and post-nephrectomy situations (P<0.01) and among the various parameters of tumor status such as tumor extent (P<0.001) and existence of metastasis (P<0.001). s-VEGF significantly correlated with the tumor volume obtained by a three-dimensional measurement (r=0.802, P<0.0001). The sensitivity and specificity of s-VEGF at the cut-off level of 100 pg/ml, as determined by the receiver-operating-characteristics curve, were 80.0% and 72.5%, respectively. The results indicate that tumor tissue of RCC liberates VEGF into the systemic blood flow and that s-VEGF is a possible marker for RCC.

Adult↗
PubMed1999

[Effects of ischemia on voiding function and nerve growth factor of the rat urinary bladder].

PURPOSE: Nerve growth factor (NGF) is synthesized in the target organs innervated by autonomic and sensory nerves so as to grow, maintain and/or repair the neurons. The present study evaluated the effects of ischemia on NGF synthesis and voiding function of the rat urinary bladder. MATERIALS AND METHODS: Bladder ischemia was induced by ligating of bilateral internal iliac arteries in the female rats. We examined the changes in the blood flow, histological structure, voiding function and NGF content of the bladder immediately, 1, 7, 14 and 28 days after the surgery. Blood flow was estimated by measuring absorbance of homogenized bladder tissue after dye injection into the abdominal aorta. Voiding function was assessed by continuous cystometry under an awake restrained condition. NGF was quantified by enzyme immunoassay (ELISA method). RESULTS: Blood flow decreased to 18% of the control immediately after the vascular ligation, and gradually recovered to 66% of the control on day 28. Histologically, epithelial ablation and thinning of muscle layer were observed on days 1 and 7. These histological disorders gradually improved to normal appearance on day 14. On day 1, while the maximum contraction pressure significantly decreased, the contraction frequency and small prevoiding contraction increased. On the other hand, the voiding efficacy markedly decreased on day 7. These functional changes recovered nearly to the control levels after day 14. NGF content transiently increased 2.4 times as the control on day 1. CONCLUSION: The present results will indicate that the voiding function deteriorated by acute ischemia is temporarily compensated by detrusor hyperrefrexia, which may be attributable to an enhanced NGF synthesis, and then improves by the development of collateral blood circulation.

Acute Disease↗
PubMed1999

[Function and nerve growth factor of the rat urinary bladder during urethral obstruction and its relief].

It has been considered that the urethral obstruction influence the function and the nerve innervation of the bladder. In this study, the changes in the bladder function and the nerve growth factor (NGF) synthesized in the bladder were systematically analyzed both during partial urethral obstruction and after its relief in the rat. The maximum contraction pressure was temporally decreased and then increased 1.5 times of the normal level 6 week after the obstruction. NGF in the bladder, measured by ELISA method, was rapidly increased 5 times of the normal level 1 day after the obstruction. It gradually decreased 2 weeks after the obstruction but did not recover to the normal level. The maximum contraction pressure and the bladder NGF recovered to the normal level after the removal of 1 to 6 weeks obstruction. These results suggest that partial urethral obstruction reversibly increases the contractility and the NGF synthesis of the bladder.

Animals↗
PubMed1999

[The role of ATP-receptor in controlling the urinary bladder and urethral function in rats].

BACKGROUND: The detrusor contraction involves an atropine resistant, nonadrenergic noncholinergic (NANC), component. Since adenosine triphosphate (ATP) has been proposed as a NANC transmitter, the role of ATP-receptors in the lower urinary tract was examined. MATERIALS AND METHODS: The isovolumetric bladder contractions and the urethral pressure were monitored after intra-arterial administration of ATP analogues and other drugs in 52 female SD rats under intraperitoneal urethane anesthesia. RESULTS: alpha beta metATP induced a rapid, phasic increase of the maximal bladder pressure immediately after the drug administration, which was followed by a decrease during the P 2 X-purinoceptor desensitization period, but it did not affect the resting bladder pressure. RB-2 did not affect both the maximal bladder pressure and the resting bladder pressure. As for the urethral functions, alpha beta metATP induced a decrease of the resting urethral pressure during the P 2 X-purinoceptors desensitization period, while RB-2 induced a increase of the resting urethral pressure in contrast. ATP, alpha beta metATP and RB-2 did not changed the maximal urethral relaxation. CONCLUSION: The results will indicate that ATP produces detrusor contractions through the P 2 X-purinoceptor. Although ATP dose not affect urethral relaxation during voiding phase, it controls the urethral tone during collecting phase by both the excitation of P 2 X-purinoceptor and the inhibition of P 2 Y-purinoceptor.

Animals↗
PubMed1999

A novel treatment of patients with chronic hepatitis C.

OBJECTIVES: Interferon alpha-2b therapy for Chronic Hepatitis C patients has been unsatisfactory. Recombinant Granulocyte Macrophage Colony-Stimulating Factor has been shown to have anti-viral effects in vivo and in vitro via cytokines release. Recently its effects on chronic hepatitis B and possibly chronic hepatitis C were reported. We, decided to conduct a pilot study to evaluate the anti-viral effects of recombinant human GM-CSF mono-therapy in patients with chronic hepatitis C and to assess its side effects. METHODS: A total of 10 patients (male/female: 5/5) (age: 34-60, mean: 45) seen in our center between 2/95 to 2/96 were randomly selected to receive recombinant human Granulocyte Macrophage Colony-Stimulating-Factor at 125 ug/m2 subcutaneously daily for two weeks followed by three times weekly for another 8 weeks. Biochemical (ALT) and viral (HCV-RNA) responses were measured prior to treatment and at weeks four and eight. Side effects were recorded. RESULTS: Six out of the ten patients treated had significant viral reduction but none became negative. Eight out the ten patients treated showed biochemical improvement and three out of the eight had normalized liver enzymes. Age, sex, stage of the disease did not influence the response but there seems to be a tendency for patients with higher pre-treatment viral level to respond virally. Side effects are minimal and well-tolerated. CONCLUSION: Recombinant human Granulocyte Macrophage Colony-Stimulating-Factor in the dose used has anti-viral effects in the majority of the chronic hepatitis C patients studied. Side effects are minimal and well tolerated. Further study with higher doses and longer duration is needed to prove its clinical efficacy in treating patients with chronic hepatitis C.

Adult↗
PubMed1998

A microsatellite genetic linkage map for zebrafish (Danio rerio).

We have constructed a zebrafish genetic linkage map consisting of 705 simple sequence-length polymorphism markers (SSLPs). The map covers 2350 centimorgans (cM) of the zebrafish genome with an average resolution of 3.3 cM. It is a complete map in genetic mapping terms (there is one linkage group for each of the 25 chromosomes), and it has been confirmed by somatic-cell hybrids and centromere-mapping using half-tetrad analysis. The markers are highly polymorphic in the zebrafish strains used for genetic crosses and provide a means to compare genetic segregation of developmental mutations between laboratories. These markers will provide an initial infrastructure for the positional cloning of the nearly 600 zebrafish genes identified as crucial to vertebrate development,and will become the anchor for the physical map of the zebrafish genome.

Animals↗
PubMed1998

Surgical repair of anterior hypospadias with fish-mouth meatus and intact prepuce based on anatomical characteristics.

PURPOSE: A variant form of anterior hypospadias, called a megameatus and intact prepuce (MIP), is thought to be less amenable to conventional distal hypospadias repair. The feasibility of using the standard technique with a parameatal-based foreskin flap is described herein. MATERIALS AND METHODS: Nine children with the MIP variant underwent repair. A foreskin flap for urethroplasty was harvested from either the ventral (Mathiew) or unilateral site. The glans was split along with the cleft glanular groove to create the glans wings. The flap was laid on the urethral plate to form a neourethra, and glanulomeatoplasty was completed by approximation of the glans wings. Sleeve reapproximation of the penile foreskin was performed for uncircumcised skin closure. RESULTS: The functional and cosmetic results of the procedure were excellent in 8 cases including 1 with temporary postoperative edema of redundant foreskin. The last case underwent excision of the ventral excess foreskin for cosmetic reasons. CONCLUSIONS: Although the etiology of the MIP variant remains obscure, the urethral plate distal to the meatus is uniformly pliable and healthy in this variant. Furthermore, the ventral portion just proximal to the meatus is well developed and not atretic so that the parameatal ventral foreskin is safely harvested for onlay urethroplasty.

Child, Preschool↗
PubMed1998

Expression of vascular endothelial growth factor gene and its receptor (flt-1) gene in urinary bladder cancer.

We investigated expression of the vascular endothelial growth factor (VEGF) gene and its receptor gene (flt-1) in 30 patients with transitional cell carcinoma (TCC) of the urinary bladder by Northern blot hybridization analysis. The VEGF transcript was observed in all of the tumors and the normal mucosae. Of the 20 tumors in which a comparative study was done, eight (40.0%) overexpressed the gene with a tumor versus normal ratio of equal to and greater than 3.0. Invasive TCCs expressed significantly more VEGF gene than superficial TCCs. Cytoplasm of tumor cells was positively stained by immunohistochemistry with an anti-VEGF monoclonal antibody, while the intratumoral endothelial cells and the vascular smooth muscle cells were weakly positive for the staining. TCCs, normal mucosae and human umbilical endothelial cells expressed flt-1 gene, while leucocytes from peripheral blood did not. The expression level of flt-1 gene significantly correlated with that of the VEGF gene in the tumor. These results indicate that the VEGF gene is frequently overexpressed in TCC of the urinary bladder, especially in muscle invasive tumors, and that a paracrine system including VEGF and flt-1 exists between the TCC cells and the adjacent endothelial cells so as to regulate the angiogenesis in this tumor.

Adult↗
PubMed1997

Effects of growth hormone and insulin-like growth factor-1 on protein metabolism, gut morphology, and cell-mediated immunity in burned rats.

The effects of recombinant human growth hormone (GH) and insulin-like growth factor-1 (IGF-1) were investigated in burned rats. Sprague-Dawley rats were fed exclusively by total parenteral nutrition and were subjected to 20% third-degree scald burns. The rats were then divided into the following three groups: (1) the GH group received GH at a dose of 1 IU.kg-1.d-1 for 2d (n = 10); (2) the IGF group received IGF-1 at a dose of 4 mg.kg-1.d-1 for 2d (n = 19); and (3) the control group received saline (n = 17). Cumulative nitrogen balance increased significantly in the GH (P < 0.01) and IGF (P < 0.01) groups as compared with the control group. There were no differences in nitrogen balance between the GH and IGF groups. Blood glucose was decreased in the IGF group (P < 0.01) and increased in the GH group (P < 0.05) as compared with the control group. The intestinal villus height and wall thickness of the GH and IGF groups were significantly greater than those of the control group. Delayed-type hypersensitivity was enhanced in both the GH and the IGF groups as compared with the control group (both P < 0.01). Furthermore, the increase in the IGF group was significantly greater than that in the GH group (P < 0.05). It was concluded that both GH and IGF-1 improve protein metabolism and immune responsiveness, as well as promote proliferation of the intestinal mucosa.

Animals↗
PubMed1997

Pharmacokinetic and pharmacological profiles of free and liposomal recombinant human erythropoietin after intravenous and subcutaneous administrations in rats.

PURPOSE: Recombinant human erythropoietin (Epo) is used frequently through intravenous (i.v.) and subcutaneous (s.c.) administration for the clinical treatment of the last stage of renal anemia. We encapsulated Epo in liposomes to develop an alternative administration route. The purpose of our study was to evaluate the pharmacokinetics and the pharmacological effects of liposomal Epo in comparison with the Epo after i.v. and s.c. administration to rats. METHODS: Epo was encapsulated in liposomes composed of dipalmitoylphosphatidylcholine (DPPC) and soybean-derived sterol mixture (SS) prepared by the reversed-phase evaporation vesicle method. After filtration through a 0.1 micron polycarbonate membrane, liposomes were gel filtered (Epo/liposomes). RESULTS: Epo/liposomes showed higher pharmacological activity than Epo/liposomes before gel filtration after i.v. administration to rats. Non-encapsulated Epo lost its activity, whereas encapsulated Epo in liposomes retained it. The pharmacological effects of Epo/liposomes were greater than those of Epo after i.v. administration. Epo/liposomes afforded 3-9 times higher AUC, lower clearance and lower steady-state volume of distribution than Epo after both i.v. and s.c. administrations. Epo/liposomes had an improved pharmacokinetics profile compared with Epo. S.c. administration of Epo/liposomes at 7 h may penetrate primarily (40% of dose) through the blood as a liposome and partly (7% of dose) in lymph. CONCLUSIONS. Epo/liposomes may reduce the frequency of injections required for a certain reticulocyte effect in comparison to Epo. The lower clearance of Epo/liposomes may increase the plasma concentrations of Epo, which increases the efficacy.

Animals↗
PubMed1996

Mermaid: a family of short interspersed repetitive elements widespread in vertebrates.

We have discovered a family of short interspersed repetitive elements (SINEs) that are present in the genomes of fish, amphibian and primates. The family of the SINEs, designated mermaid, is distinctive in each species except for a conserved region of approximately 80 bp. Some members of the mermaid family were found in transposon-like repetitive elements, including Tcl-like elements which were also distributed in the genomes of fish and amphibian. This raises the possibility of horizontal transfer of the mermaid family between vertebrates via transposons.

Amphibians↗
PubMed1996

Mermaid, a family of short interspersed repetitive elements, is useful for zebrafish genome mapping.

A family of short interspersed repetitive elements (SINEs), designated mermaid, is present in the genomes of fish, amphibian and primates, but absent in the mouse genome. We have demonstrated that the sequences of the mermaid family are highly polymorphic in the zebrafish genome as in the human genome. We have also shown that the mermaid sequence can be used to recover zebrafish specific DNA from zebrafish-mouse cell hybrids by using mermaid-specific oligonucleotides as PCR primers. Thus, the mermaid family serves as a valuable genetic tool for the zebrafish genome mapping.

Animals↗
PubMed1996

Oral administration of recombinant human erythropoietin in liposomes in rats: influence of lipid composition and size of liposomes on bioavailability.

Intestinal absorption of recombinant human erythropoietin (Epo) encapsulated in liposomes (Epo/liposomes) was examined by measuring the pharmacological effects of Epo after oral administration in rats. Circulating reticulocyte counts after oral administration of Epo/liposomes showed a profile different from that after intravenous administration. Epo/liposomes 0.1 micron in diameter were absorbed more effectively than those 0.2 micron in diameter. In the 0.1 micron Epo/liposomes composed of dipalmitoylphosphatidylcholine (DPPC) and soybean-derived sterols (SS), cholesterol (Ch), or soybean-derived sterylglucosides (SG), DPPC/SS (in molar ratio 7/2) and DPPC/Ch (7/2) showed higher efficiency in intestinal absorption than DPPC/Ch (7/4) and DPPC/SG (7/2) at a low dose by the sysmex method. Pharmacological availabilities for oral administration of Epo/liposomes were 0.74-31% and 3.3-30% as evaluated by circulating reticulocyte counts and percentage circulating reticulocytes of erythrocytes, respectively, in comparison to those for intravenous administration of the same dose.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed1995

Effects of dose, pH and osmolarity on intranasal absorption of recombinant human erythropoietin in rats.

The effects of dose, pH and osmolarity on the intranasal absorption of a recombinant human erythropoietin (rEPO) solution were studied in male Wistar rats. The intranasal administration of rEPO was evaluated by measuring percentage circulating reticulocytes of red blood cells on a stained blood smear (smear method), and also by measuring residual circulating reticulocyte counts using a microcell counter (sysmex method). Both results suggest that rEPO solution was absorbed through the nasal mucosa of rats without enhancers after a single intranasal administration. The pharmacological availabilities of rEPO after intranasal administration compared with intravenous administration were about 7% and 4%, when estimated by smear method and sysmex method, respectively. The pharmacological activity was enhanced in low pH and hypotonic mannitol solution.

Absorption↗