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Biomedical subjects

H Hamada

Publications and source records attributed to H Hamada.

At least 253 records · Page 14Linked to original sources
PubMed1998

[Endoscopic third ventriculostomy in a case of obstructive hydrocephalus with neurofibromatosis (NF-1)].

Endoscopic third ventriculostomy in a case of obstructive hydrocephalus with neurofibromatosis (NF-1) was reported. The patient was a 25-year-old male, who suffered from progressive headache and somnolence. He underwent a ventriculoperitoneal shunt at the age of 11 years. After that, 8 times of shunt revision and unilateral subtemporal decompression were performed during 14 years until this admission. The programmable valve system was used at the last procedure. On admission, computed tomography (CT) scan showed marked enlarged lateral and third ventricles. The patient was diagnosed as hydrocephalus resulting from shunt malfunction. An endoscopic third ventriculostomy was performed and his symptoms improved immediately. The size of the lateral and third ventricles was revealed normal on the CT 18 months after the third ventriculostomy.

Adult↗
PubMed1998

Effects of wine on plasma fibrinolytic and coagulation systems.

The in-vitro effects of citrus, red and white wines on human plasma fibrinolytic enzymes were compared. When citrus wine was added to plasmin, H-D-Val-Leu-Lys-pNA (S-2251) amidolysis was not changed. Although, it was significantly inhibited when red and white wines were added. The pyro-Glu-Gly-Arg-pNA (S-2444) amidolysis of the plasminogen activator urokinase was inhibited by all types of wine. Since the same amount of Et-OH as the wine's content did not effect on these inhibitions, it can be assumed to be due to other unknown substances in wines besides alcohol. In in-vivo test of 20 normal volunteers (ages 20-52) with various wines equivalent to 30-60 ml of alcohol content, the coagulation parameters of gamma and kappa values on thromboelastography were not so much changed after 1-2 hrs of the application. Also, there was not much difference of the fibrinolytic parameters in terms of the plasma euglobulin clotlysis time, S-2444 amidolysis, and Ma values on thromboelastography. However, the protein concentration and the enzyme activity of the urokinase-like plasminogen activator, which were extracted from the plasma of volunteers who had the citrus wine 1 hr before the test were higher than twice of the before control. The main molecular form of this enzyme was proved to have a molecular weight of about 30,000 by zymography. It is concluded that not only wines induce the endogenous plasminogen activator just like other alcoholic beverages but also wines contain a fibrinolysis inhibitor which works directly to the enzyme dissolubility. This finding warns that extremely complex results can be expected depending on the test method.

Adult↗
PubMed1998

[Intra-arterial preventive chemotherapy for residual liver after resection of hepatic metastasis from colorectal cancer].

We treated 18 cases with intra-hepatic arterial infusion chemotherapy after resection of hepatic metastasis from colorectal cancer (June 1991-September 1997). Eight cases were H1, 7 were H2, and 3 were H3. Hepatic lobectomy was done in 3 cases, lobectomy + partial resection in 2 cases, and partial resection in 13 cases. All cases received high-dose intermittent 5-FU infusion (WHF = 5-FU 1,000 mg/m2/5 hrs/w) on an outpatient basis. The total frequency of WHF was 4-54 times (average 29), and total 5-FU doses ranged from 6.0 to 81.0 g (average 40 g). The 1- and 5-year cumulative survival rates were 100% and 77.5% in all patients 100% and 87.5% in H1 group and 100% and 64.3% in H2 + H3 group, respectively. There was no significant difference of survival between the H1 and H1 + H3 groups. The 1- and 5-year recurrence rates in residual liver were 5.9% and 14.4%, respectively. One of 2 cases with residual liver recurrence was resected for metastasis again, and the patient is now in a disease-free state. WHF after resection of hepatic metastasis from colorectal cancer has a preventive effect for their survival, not only in H1 group but also in H2 + H3 group.

Antimetabolites, Antineoplastic↗
PubMed1998

[Dissecting aneurysm of the extracranial vertebral artery causing TIA: a case report].

Spontaneous dissecting aneurysm of the extracranial vertebral artery is not frequent. We report a case of dissecting aneurysm of the left extracranial vertebral artery causing TIA. A 44-year-old man was admitted to our hospital with severe occipitalgia of sudden onset on Dec. 21, 1995. On admission, he presented with left hemiparesis and left hemidysesthesia. CT scan and SPECT showed no abnormal findings. His neurological deficits completely improved on the following day. Initial cerebral angiography performed on Dec. 27, 1995 showed pearl and string sign at V3 segment and irregular stenosis at V2 segment suggesting a dissecting aneurysm. We treated conservatively. Repeated angiography performed four weeks after the onset showed resolution of the stenosic lesion and disappearance of the aneurysm. We discussed diagnosis and etiology and treatment of dissecting aneurysm of the extracranial vertebral artery.

Adult↗
PubMed1998

[Gene transduction for experimental brain tumors using recombinant adenovirus vector].

Recent advances in molecular biology have permitted significant progress toward the treatment of malignant brain tumors using gene transduction methods. Adenovirus vectors have recently been shown to transduce genes successfully into brain tumor cells both in vitro and in vivo. We have investigated the feasibility of gene transduction for brain tumors using adenovirus vectors. To evaluate in vitro transduction rate by adenovirus vectors, rat 9L gliosarcoma cells or human glioblastoma cells were infected with recombinant replication-deficient adenovirus vectors containing the E. coli beta-galactosidase gene (Adex-CALacZ) and stained with X-Gal. We observed a multiplicity of infection (MOI)-dependent rate. Approximately 100% transgene expression was achieved at a MOI of 5 after seven days of incubation. To evaluate transgene expression in a rat brain tumor model, AdexCALacZ was stereotactically injected into established rat 9L brain tumors. Intratumoral injection of AdexCALacZ resulted in high transgene expression in tumor cells. Although injection of AdexCALacZ in the normal basal ganglia resulted in broad and diffuse transduction into endogenous neural cells, direct intratumoral injection resulted in transduction that was relatively restricted to the tumor cells as well as some neighboring normal cells. Transduction rates were relatively elevated at the margin of the tumor. Our results suggest that adenovirus vectors might be a feasible method to transfer therapeutic genes into malignant brain tumors.

Adenoviridae↗
PubMed1998

[Clinical evaluation of fundic gland polyps and hyperplastic polyps].

We performed a retrospective review of 477 cases of fundic gland polyps compared with 562 cases of hyperplastic polyps, which were detected endoscopically during the past 8 years between January, 1989 and December, 1996. All lesions were histologically confirmed by endoscopic biopsy or the examination of polypectomy specimens. Fundic gland polyps were more prevalent in middle aged-female, and were not associated with gastric adenomas and gastric cancers. These results suggested that the background mucosa of patients with fundic gland polyp was different from that of patients with hyperplastic polyp. Fundic gland polyps in 55 patients were followed up. No change was observed in the polyps of the about half subjects, the polyps of 12 cases (21.8%) decreased in size and number or resolved completely. Cases decreased in size and number or resolved completely were much more in fundic gland polyps than hyperplastic polyps. There were no malignant transformation of fundic gland polyps. We claimed that fundic gland polyps were benign and distinct from hyperplastic polyps which had a possibility of malignant transformation.

Aged↗
PubMed1998

[Evaluation of eosinophilic cationic protein levels in patients with eosinophilic pneumonia].

We investigated the significance of eosinophilic cationic protein (ECP) as a biological indicator of disease activity in patients with eosinophilic pneumonia (EP). ECP levels were measured in serum and bronchoalveolar lavage fluid (BALF) samples from patients with EP or other diffuse interstitial lung diseases and from healthy subjects. Also we performed immunohistochemical staining of lung tissue sections from patients with EP using anti-EG 2 antibody, and computed the correlation between the number of EG 2-positive cells in lung tissues and ECP levels in serum and BALF from patients with EP. Levels of ECP in serum and BALF samples from patients with EP were significantly elevated compared to the levels in samples from other interstitial lung-disease patients and healthy subjects. Additionally, changes in serum ECP levels reflected the clinical courses for EP patients. Approximately 90 percent of the infiltrated eosinophils in tissue sections from patients with EP were EG 2-positive and activated. The number of EG 2-positive cells in lung tissues correlated significantly with levels of ECP in serum and BALF samples from patients with EP. These findings suggested that ECP levels in serum and BALF reflect the degree of eosinophil activation in lung tissues and the degree of disease activity in patients with EP. We concluded that ECP may serve as a useful biological indicator in EP.

Biomarkers↗
PubMed1997

Development of a novel selective amplifier gene for controllable expansion of transduced hematopoietic cells.

To overcome the low efficiency of gene transfer into hematopoietic cells, we developed a novel system for selective expansion of transduced cells. To this end, we constructed a chimeric cDNA (GCRER) encoding the fusion protein between the granulocyte colony-stimulating factor receptor (G-CSFR) and the hormone-binding domain (HBD) of the estrogen receptor (ER) as a selective amplifier gene. Use of the intracellular signaling pathway of G-CSFR was considered to be appropriate, because G-CSF has the ability not only to stimulate the neutrophil production, but also to expand the hematopoietic stem/progenitor cell pool in vivo. To activate the exogenous G-CSFR signal domain selectively, the estrogen/ER-HBD system was used as a molecular switch in this study. When the GCRER gene was expressed in the interleukin-3 (IL-3)-dependent murine cell line, Ba/F3, the cells showed IL-3-independent growth in response to G-CSF or estrogen. Moreover, the Ba/F3 cells transfected with the Delta(5-195)GCRER, whose product lacks the extracellular G-CSF-binding domain, did not respond to G-CSF, but retained the ability for estrogen-dependent growth. Further, murine bone marrow cells transduced with the GCRER or Delta(5-195)GCRER gene with retroviral vectors formed a significant number of colonies in response to estrogen, as well as G-CSF, whereas estrogen did not stimulate colony formation by untransduced murine bone marrow cells. It is noteworthy that erythroid colonies were apparently formed by the bone marrow cells transduced with the GCRER gene in the presence of estrogen without the addition of erythropoietin, suggesting that the signals from the G-CSFR portion of the chimeric molecules do not preferentially induce neutrophilic differentiation, but just promote the differentiation depending on the nature of the target cells. We speculate that when the selective amplifier genes are expressed in the primitive hematopoietic stem cells, the growth signal predominates and that the population of transduced stem cells expands upon estrogen treatment, even if some of the cells enter the differentiation pathway. The present study suggests that this strategy is applicable to the in vivo selective expansion of transduced hematopoietic stem cells.

Animals↗
PubMed1997

GM-CSF and B7-1 (CD80) co-stimulatory signals co-operate in the induction of effective anti-tumor immunity in syngeneic mice.

B7-1 (CD80) co-stimulatory molecule gene-transduced Lewis lung carcinoma (LLC) cells (LLC/B7 cells) resulted in remarkable loss of tumorigenicity in syngeneic C57BL/6 mice (87.5% rejection) compared to B7-negative, wild-type LLC (LLC/wt) cells (0% rejection). However, mice that had rejected LLC/B7 cells developed almost no systemic immunity protective against challenge with wild-type tumor cells after 4 weeks (11.8% rejection). Enhancement of MHC class I (H-2Kb) expression of LLC/B7 cells with in vitro interferon-gamma treatment did not result in enhancement of protective immunity. In vivo depletion assay revealed that abrogation of tumorigenicity in LLC/B7 depended on CD8+ T cells but not on CD4+ T cells. However, vaccination of C57BL/6 mice with irradiated LLC cells transduced with GM-CSF (LLC/GM) led to the induction of potent, specific immunity against challenge with the LLC/wt cells after 2 weeks (80.8% rejection). Next, we established a double transfectant of LLC cells expressing both B7-1 and GM-CSF (LLC/GM + B7). The tumorigenicity of these clonal cells was also remarkably suppressed (90% rejection) to the same degree as LLC/B7, whereas that of LLC/GM was not suppressed (0% rejection). Interestingly, mice that had rejected LLC/GM+B7 cells developed enhanced protective immunity against challenge with LLC/wt cells after 4 weeks (55.6% rejection) compared to the results of LLC/B7 cells (11.8%). To evaluate whether co-expression of GM-CSF and B7-1 enabled the tumor cells to activate cytotoxic T cells more efficiently than B7-1 alone, we performed an in vitro killing assay. We found that immunization with LLC/GM+B7 cells resulted in a 3-fold stronger cytotoxic response than that with LLC/B7. Our data indicate that co-transfection of the B7-1 co-stimulatory molecule and GM-CSF genes may be more effective for the induction of stronger protective immunity in this experimental system.

Animals↗
PubMed1997

In vivo selective gene expression and therapy mediated by adenoviral vectors for human carcinoembryonic antigen-producing gastric carcinoma.

Previously, we reported that adenoviral vectors carrying the carcinoembryonic antigen (CEA) promoter sequences to direct the Echerichia coli beta-galactosidase gene (AdCEA-lacZ) or cytosine deaminase (CD) gene (AdCEA-CD) confer selective gene expression on a CEA-positive gastric cancer cell line (MKN45) in vitro. Here, adenovirus-mediated tumor-specific gene therapy for CEA-positive gastric carcinoma in vivo was investigated. Using an animal model with i.p. disseminated MKN45 tumors, adenovirus-mediated tumor-specific transgene expression and therapeutic efficacy were analyzed. After an i.p. injection of AdCEA-lacZ, beta-galactosidase activity was confined to tumor xenografts. Moreover, CD mRNA was expressed exclusively in MKN45 tumor xenografts after infection with AdCEA-CD, despite the fact that an adenovirus-mediated transfer of CD DNA was detected in all tissues tested. In contrast, CD mRNA was detected not only in tumor xenografts but also in other organs of mice infected with AdCA-CD, in which CD gene expression is governed by an ubiquitous promoter. Suppression of tumor growth and prolongation of survival were noted in tumor-bearing mice treated with AdCEA-CD and 5-fluorocytosine (5FC) without observable adverse effects. In contrast, significant hepatic toxicity was noted in animals treated with AdCA-CD. These results reveal that the CEA promoter restricts CD gene expression to CEA-positive tumor cells in the adenoviral context in vivo, along with the beneficial therapeutic effects of 5FC treatment, suggesting the i.p. AdCEA-CD/5FC system may provide a novel approach to treatment of i.p. disseminated gastric cancer.

Animals↗
PubMed1997

Metabolic inactivation of retinoic acid by a novel P450 differentially expressed in developing mouse embryos.

Retinoic acid (RA) is a physiological agent that has a wide range of biological activity and appears to regulate developmental programs of vertebrates. However, little is known about the molecular basis of its metabolism. Here we have identified a novel cytochrome P450 (P450RA) that specifically metabolizes RA. In vitro, P450RA converts all-trans RA into 5,8-epoxy all-trans RA. P450RA metabolizes other biologically active RAs such as 9-cis RA and 13-cis RA, but fails to metabolize their precursors, retinol and retinal. Overexpression of P450RA in cell culture renders the cells hyposensitive to all-trans RA. These functional tests in vitro and in vivo indicate that P450RA inactivates RA. The P450RA gene is not expressed uniformly but in a stage- and region-specific fashion during mouse development. The major expression domains in developing embryos include the posterior neural plate and neural crest cells for cranial ganglia. The expression of P450RA, however, is not necessarily inducible by excess RA. These results suggest that P450RA regulates the intracellular level of RA and may be involved in setting up the uneven distribution of active RA in mammalian embryos.

Amino Acid Sequence↗
PubMed1997

Predominant expression of Brn-2 in the postmitotic neurons of the developing mouse neocortex.

The expression of Brn-2, a central nervous systems (CNS)-specific POU domain transcription factor, in the developing mouse neocortex was examined with an anti-Brn-2 antibody. Brn-2 protein was first detected in CNS on embryonic day (E) 11.5, and remained strong until E15.5. From E11.5 to postnatal day (P) 0, a high level of Brn-2 expression was observed in the subventricular zone, the intermediate zone, and the outer layer of the neocortex, but not in the ventricular zone. In the double-staining experiments, most of the Brn-2 positive cells were also positive for NCAM-H, an adhesion molecule specific to post-mitotic neurons. Furthermore, BrdU-labeling experiments demonstrated the presence of Brn-2 protein exclusively in postmitotic cells. These results indicated that, in the developing neocortex, Brn-2 expression is up-regulated after the final cell division. Therefore, this transcription factor may be involved in the migration and/or maturation process of the immature neuronal cells.

Animals↗
PubMed1997

VSV-G-pseudotyped retroviral packaging through adenovirus-mediated inducible gene expression.

It has been technically difficult to generate recombinant adenoviruses encoding genes for cytotoxic products such as vesicular stomatitis virus G-protein (VSV-G), which is too toxic for the host cells to allow adenoviral propagation. In our companion paper (Yoshida, Y., and Hamada, H., Biochem. Biophys. Res. Commun., 230, 426-430, 1997), a tetracycline-inducible adenovirus system is reported. The inducible expression system enabled us to generate recombinant adenoviruses encoding genes for the cytotoxic viral VSV-G product. In this study, we generated recombinant adenoviruses encoding VSV-G and MoMLV gag-pol genes, both under the tetracycline-controllable promoter, and attempted retroviral packaging. Simultaneous infection of these adenoviruses together with tetracycline-transactivator (NtTA) expression resulted in efficient VSVG-pseudotyped retroviral packaging. Adenovirus-mediated recombinant retrovirus generation will be useful in studies with various pseudotyped mutants, as well as in assays for retrovirus-related genes and their products.

Adenoviridae↗
PubMed1997

Adenovirus-mediated gene therapy of gastric carcinoma using cancer-specific gene expression in vivo.

The carcinoembryonic antigen (CEA) is a glycoprotein which overexpressed in the majority of human gastric cancers. We demonstrated that recombinant adenoviral vector (AdCEAtk), containing the CEA promoter, could transfer the herpes simplex virus thymidine kinase (HSVtk) gene into CEA-producing gastric cancer cells to confer sensitivity to ganciclovir (GCV) in vivo. In an ex vivo experiment, the tumor growth was inhibited after GCV treatment when the tumor contained more than 20% of AdCEAtk infected cells, indicating an efficient bystander killing effect. With intra-tumoral injection of AdCEAtk, the HSVtk were selectively expressed in approximately 30% of CEA producing cancer cells. By AdCEAtk injection and GCV administration, the growth of tumors was significantly inhibited by 20% as compared to untreated tumors. It is hoped that these results provide a strategy of tumor specific gene transfer for CEA producing gastric cancers.

Adenoviridae↗
PubMed1997

In vivo gene therapy for alpha-fetoprotein-producing hepatocellular carcinoma by adenovirus-mediated transfer of cytosine deaminase gene.

The alpha-fetoprotein (AFP) gene is normally expressed in fetal liver and is transcriptionally silent in adult liver but overexpressed in human hepatocellular carcinoma (HCC). Here, we demonstrate that replication defective recombinant adenoviral vectors, containing the human AFP promoter/enhancer, can be used to express the Escherichia coli cytosine deaminase (CD) gene (AdAFPCD) and the beta-galactosidase gene (AdAF-PlacZ) in AFP-producing HCC cell lines. Expression of the CD gene by adenovirus from the AFP promoter/enhancer (AdAFPCD) induced cells sensitive to 5-fluorocytosine (5FC) in the AFP-producing cells but not in the AFP-nonproducing cells. Transduction by an adenoviral vector harboring an ubiquitous strong promoter and CD gene showed enzymatic activity and 5FC killing in all cell lines. When AdAFPlacZ was injected into the s.c. established hepatoma in vivo, expression of the beta-galactosidase gene was confined to AFP-producing HCC xenografts. Moreover, HCC xenografts regressed by transduction with AdAFPCD and subsequently with 5FC treatment in vivo. These findings suggest that utilization of the AFP promoter/enhancer in an adenoviral vector can confer selective expression of a heterologous suicide gene in hepatocellular carcinoma cells in vitro and in vivo.

Adenoviridae↗
PubMed1997

Adenovirus-mediated inducible gene expression through tetracycline-controllable transactivator with nuclear localization signal.

Tetracycline-controllable expression vectors are widely used for inducible expression in mammalian cells. The limitation of this system is the difficulty in expressing high levels of the chimeric transactivator tTA. In this study, we demonstrate a utility of recombinant adenoviruses for the tetracycline-controllable expression system. Unexpectedly, the original tTA transactivator did not show sufficient regulation of the reporter gene expression driven by the tetracycline-responsive promoter (Tet). By adding the nuclear localization signal on the tTA transactivator (NtTA), we achieved tight regulation and high-level induction of the reporter gene expression. The NtTA driven by various promoters demonstrated strict tetracycline controllability at 1 microg/ml of tetracycline and above. The methodology for adenovirus-mediated inducible gene expression has wide applicability. Controllable expression of cytotoxic viral proteins will be applicable for antiviral vaccine productions and pseudotype viral vector generations.

Adenoviruses, Human↗