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Biomedical subjects

A Igarashi

Publications and source records attributed to A Igarashi.

At least 37 records · Page 2Linked to original sources
PubMed2001

Increase in bone growth factors with healing rat fractures: the enhancing effect of zinc.

The effect of zinc, a stimulator of bone formation, on bone protein components in the femoral-diaphyseal tissues with fracture healing was investigated. Rats were sacrificed between 1 and 7 days after the femoral fracture, and the diaphyseal tissues were cultured in a serum-free Dulbecco's modified Eagle's medium for 24 h. Protein content in the femoral-diaphyseal tissues was markedly elevated by fracture healing. The amount of protein in the medium cultured with the diaphyseal tissues obtained from fracture healing rats was markedly elevated as compared with that of normal rats, indicating that bone protein components were secreted into culture medium. Analysis with sodium dodecyl sulfate-polyacrylamide gel elecrophoresis (SDS-PAGE) showed that many protein molecules were secreted from the diaphyseal tissues with fracture healing. Especially, protein molecule of about 66 kDa was markedly secreted by fracture healing. The presence of zinc acexamate (10(-5) and 10(-4) M) in culture medium induced a significant elevation of medium protein content; the zinc effect was enhanced by culture with the diaphyseal tissues of fracture healing rats. Also, the culture of diaphyseal tissues with fracture healing caused a significant increase in insulin-like growth factor-I (IGF-I) and transforming growth factor-beta1 (TGF-beta1) in culture medium. The production of IGF-I and TGF-beta1 from bone tissues with fracture healing was significantly enhanced in the presence of zinc acexamate (10(-6)-10(-4) M). Moreover, the addition of IGF-I (10(-8) M) or TGF-beta1 (10(-10) M) in a culture medium caused a significant elevation of protein content in the medium cultured with the femoral-diaphyseal tissues from normal and fracture healing rats. The effect of IGF-I or TGF-beta1 was significantly enhanced in the presence of zinc acexamate (10(-4) M). Also, deoxyribonucleic acid (DNA) content in the diaphyseal tissues from normal and fracture healing rats was significantly raised by the culture with IGF-I or TGF-beta1. The effect of IGF-I was significantly enhanced by zinc. The present study demonstrates that fracture healing increases production of bone IGF-I and TGF-beta1, and that this elevation is enhanced by zinc treatment.

Aminocaproates↗
PubMed2001

[Effective combination chemotherapy for a recurrent case of carcinoma of the remnant stomach].

A 69-year-old-man underwent distal gastrectomy for gastric carcinoma in 1988. Another gastric carcinoma was discovered in the remnant stomach in March 1995. Total gastrectomy and lymph node dissection were performed. CEA was up and we detected a big left suprarenal mass by abdominal CT. Suprarenalectomy was performed in June 1997. The swelling of lymph nodes was detected by CT and CEA was up to 1,000. Combination chemotherapy with intermittent 5-fluorouracil (5-FU) and low-dose cisplatin (CDDP) was performed. CEA suddenly decreased and lymph node swelling was reduced.

Adenocarcinoma↗
PubMed2000

Identification of the putrescine recognition site on polyamine transport protein PotE.

The PotE protein can catalyze both uptake and excretion of putrescine. The K(m) values of putrescine for uptake and excretion are 1.8 and 73 microm, respectively. Uptake of putrescine is dependent on the membrane potential, whereas excretion involves putrescine-ornithine antiporter activity. Amino acids involved in both activities were identified using mutated PotE proteins. It was found that Cys(62), Trp(201), Trp(292), and Tyr(425) were strongly involved in both activities, and that Tyr(92), Cys(210), Cys(285), and Cys(286) were moderately involved in the activities. Mutations of Tyr(78), Trp(90), and Trp(422) mainly affected uptake activity, and the K(m) values for putrescine uptake by these PotE mutants increased greatly, indicating that these amino acids are involved in the high affinity uptake of putrescine by PotE. Mutations of Lys(301) and Tyr(308) mainly affected excretion activity (putrescine-ornithine antiporter activity), and excretion by these mutants was not stimulated by ornithine, indicating that these amino acids are involved in the recognition of ornithine. It was found that the putrescine and ornithine recognition site on PotE is located at the cytoplasmic surface and the vestibule of the pore consisting of 12 transmembrane segments. Based on the results of competition experiments with various putrescine analogues and the disulfide cross-linking of PotE between cytoplasmic loops and the COOH terminus, a model of the putrescine recognition site on PotE consisting of the identified amino acids is presented.

Amino Acid Sequence↗
PubMed2000

Role of the DExH motif of the Japanese encephalitis virus and hepatitis C virus NS3 proteins in the ATPase and RNA helicase activities.

The role of the conserved DExH motif of the Japanese encephalitis virus (JEV) NS3 protein in the ATPase and RNA helicase activities was compared with that of the hepatitis C virus (HCV) NS3 protein. In the DExH motif of JEV NS3, Asp-285 and Glu-286 were essential for both ATPase and RNA helicase activities. Cys-287 was critical for the RNA helicase activity of JEV NS3 but not for ATPase activity. A His-288-to-Ala substitution in the DExH motif of HCV NS3 resulted in an increase in ATPase activity which was suppressed by poly(U). In contrast, alanine substitution at the same site in JEV NS3 did not increase basal ATPase activity which remained to be stimulated by poly(U). Thus, the mutational effect at His in motif II was different in the HCV and JEV NS3 proteins. Mutagenesis at His-288 of JEV NS3 revealed that His was the most preferable amino acid for ATPase activity and Ala, Gly, Asn, Gln, Ser, or Arg could partly substitute for it. However, any other mutation at His-288 completely disrupted the RNA helicase activity of JEV NS3. The results suggest that Cys-287 and His-288 are essential residues especially for the RNA helicase activity of JEV NS3 and the ATPase and helicase activities are separable enzymatic functions.

Adenosine Triphosphatases↗
PubMed2000

Identification and characterization of the RNA helicase activity of Japanese encephalitis virus NS3 protein.

The NS3 protein of Japanese encephalitis virus (JEV) contains motifs typical of RNA helicase/NTPase but no RNA helicase activity has been reported for this protein. To identify and characterize the RNA helicase activity of JEV NS3, a truncated form of the protein with a His-tag was expressed in Escherichia coli and purified. The purified JEV NS3 protein showed an RNA helicase activity, which was dependent on divalent cations and ATP. An Asp-285-to-Ala substitution in motif II of the JEV NS3 protein abolished the ATPase and RNA helicase activities. These results indicate that the C-terminal 457 residues are sufficient to exhibit the RNA helicase activity of JEV NS3.

Adenosine Triphosphatases↗
PubMed2000

Interventricular methotrexate therapy for carcinomatous meningitis due to breast cancer: a case with leukoencephalopathy.

A 46-year-old woman presented with paraplegia and severe lumbago. She had had a radical mastectomy for left breast cancer 10 years earlier, and 6 months prior to presentation she completed CMF chemotherapy for treatment of retroperitoneal metastasis. CT and MRI to identify potential causes of the paraplegia and lumbago showed leptomeningeal carcinomatosis due to dissemination from invasive recurrence of the retroperitoneal tumor. An Ommaya reservoir was inserted, and infusion of intrathecal methotrexate (MTX; 5 mg twice weekly) began. Her clinical symptoms improved after receiving 53 mg MTX. However, after receiving 83 mg MTX, the patient became dizzy from leukoencephalopathy. Although administration of prednisolone mostly resolved her symptom, the patient died 9 months after the diagnosis of carcinomatous meningitis.

Antimetabolites, Antineoplastic↗
PubMed2000

Characterization of autoantibodies to endothelial cells in systemic sclerosis (SSc): association with pulmonary fibrosis.

To determine the prevalence and the characterization of antibodies to endothelial cells in patients with SSc, serum samples from 80 patients with SSc, 20 patients with systemic lupus erythematosus (SLE), and 20 healthy control subjects were examined by ELISA using cultured human umbilical vein endothelial cells (HUVEC), indirect immunofluorescence analysis (IIF), and immunoblotting using cytoplasmic extract of HUVEC. IgG and/or IgM isotype anti-endothelial cell antibodies (AECA) were demonstrated by ELISA in 43 of 80 patients with SSc (54%), in 15 of 20 patients with SLE (75%), and in none of 20 healthy control subjects. Immunofluorescence analysis on HUVEC substrate showed homogeneous cytoplasmic staining. Immunoblotting demonstrated that these patients had antibodies directed to one or several antigens of approximately 60, 90, 110 and 140 kD, and the most common responses were to the 90-kD antigen. By the immunofluorescence method using HUVEC, affinity-purified anti-90-kD antibodies showed identical cytoplasmic staining to that produced by sera positive for AECA. Furthermore, AECA were closely correlated with pulmonary fibrosis in patients with SSc. These findings suggest that patients with SSc have abnormal antibodies to endothelial cell antigens, and support the hypothesis that endothelial dysfunction is involved in the development of this disease.

Adult↗
PubMed2000

Severity-related molecular differences among nineteen strains of dengue type 2 viruses.

Comparative nucleotide sequencing was carried out on dengue type 2 virus (DEN-2) strains isolated from patients in Northeast Thailand during the epidemic season in 1993. The patients exhibited different clinical manifestations ranging from dengue fever (DF) to dengue haemorrhagic fever (DHF)/dengue shock syndrome (DSS). The results classified 19 DEN-2 strains into 3 subtypes according to nonsynonymous amino acid replacements. The strain isolated from a DSS patient eliciting secondary serological response belonged to subtype I, whereas 13 strains isolated from DHF patients with secondary response and 2 strains from DF patients with primary response belonged to subtype II. On the other hand, 3 strains isolated from DF cases evoking either primary or secondary response belonged to subtype III. These results suggest that subtype III virus infection could result in clinically milder manifestation irrespective of the serological response compared with subtype I or II viruses. The RNA secondary structure predicted for the 3' noncoding region showed 4 different structures (A, B, C, and D). The result also indicates that different subtypes of DEN-2 serotypes are circulating in a single epidemic in Thailand.

3' Untranslated Regions↗
PubMed2000

Association of intrauterine growth retardation with monosomy of the terminal segment of the short arm of the X chromosome in patients with Turner's syndrome.

Short stature, which may be a result of intrauterine growth retardation (IUGR), is a characteristic of Turner's syndrome. However, the loci responsible for IUGR have not been well studied. We reviewed the birth records of 74 patients with Turner's syndrome: 20 with pure X monosomy, 44 with X-mosaicisms, and 10 with X-structural abnormalities. The overall incidence of IUGR was 39.2% (29 of 74 patients). The SHOX gene is encoded in a terminal segment of the short arm of the X chromosome. In 39 patients where two copies of the SHOX gene were absent, the incidence of IUGR was 46.2% (18 of 39 patients). In 14 patients with two copies of the SHOX gene, the incidence of IUGR was significantly lower at 7.1% (1 of 14 patients). Our results suggest that SHOX influences in utero growth in Turner's syndrome.

Comorbidity↗
PubMed2000

Molecular evolution, distribution and genetic relationship among the dengue 2 viruses isolated from different clinical severity.

Twenty-two strains of dengue 2 virus, isolated in China, Latin America, New Guinea and Thailand were subjected to phylogenetic analysis. The UPGMA analysis was carried out on each gene region of dengue virus and demonstrated that outcome from most of the gene regions showed similar results except those from NS4B and YUTR with very short nucleotide length. Among ten regions examined, the results from E gene documented the geographical differences of the virus strains most clearly and all the American strains (Mara 4, IQT1797 and S1) were distantly related to the Asian isolates. As for the 16 Thai strains isolated in 1993, they were clustered into three groups and a strain from a DSS patient formed a distinct branch compared to the other two groups. This finding from phylogenetic analysis is consistent with earlier conclusion and support the severity related subtyping of dengue 2 virus based on amino acid changes.

3' Untranslated Regions↗
PubMed2000

IgM-capture ELISA of serum samples collected from Filipino dengue patients.

Viral antigens for 4 dengue serotypes were produced in C6/36 Aedes albopictus cells. These were used as assay antigens for IgM-capture ELISA to detect IgM antibodies in sera of dengue patients from 3 hospitals in Metro Manila, Philippines. A total of 378 serum samples came from National Children's Hospital (NCH), San Lazaro Hospital (SLH), and St Luke's Medical Center (SLMC), from January to November 1995. Three hundred and four (304) out of 378 serum samples, or 80.42% showed positive IgM ELISA titer against at least one of the 4 assay antigens. Dengue type 4 (D4) antigen detected antibodies in 61.90% (234/378) of these serum samples, whereas type 1 (D1), type 3 (D3), and type 2 (D2) had detection rates of 60.05% (227/378), 50.79% (192/378) and 49.47% (187/378) respectively. Although the results show that both D1 and D4 are the most effective antigens in identifying dengue infections for this batch of samples, the use of a cocktail of antigens is still recommended. The results of this study are the basis for the IgM-capture ELISA protocol presently applied for the laboratory confirmation of dengue cases in the Philippines.

Aedes↗
PubMed1999

Role and interaction of connective tissue growth factor with transforming growth factor-beta in persistent fibrosis: A mouse fibrosis model.

Skin fibrotic disorders are understood to develop under the influence of some growth factors, such as transforming growth factor-beta (TGF-beta), basic fibroblast growth factor (bFGF), or connective tissue growth factor (CTGF). To establish an appropriate animal model of skin fibrosis by exogenous application of growth factors, we investigated the in vivo effects of growth factors by injecting TGF-beta, CTGF, and bFGF into the subcutaneous tissue of newborn mice. A single application of TGF-beta or bFGF resulted in the formation of transient granulated tissue that disappeared despite 7 days of consecutive injections. A single CTGF injection also caused slight granulation. However, injecting TGF-beta plus CTGF produced long-term fibrotic tissue, which persisted for at least 14 days. Also, fibrotic tissue was observed when CTGF was injected from 4 to 7 days after TGF-beta injections for the first 1-3 days. In situ hybridization analysis revealed the expression of CTGF mRNA in the fibroblasts at least in a few fibrotic conditions. These findings suggest that either CTGF mRNA or an application of exogenous CTGF protein is required for the development of persistent fibrosis. From our study, it appears that interaction of several growth factors is required for persistent fibrotic tissue formation, with TGF-beta causing the induction and CTGF needed for maintenance of skin fibrosis. The animal model on skin fibrosis by exogenous application of growth factors developed in this study may prove useful for future studies on fibrotic disorders.

Animals↗
PubMed1999

Effect of vitamin K2 (menaquinone-7) in fermented soybean (natto) on bone loss in ovariectomized rats.

The effect of dietary vitamin K2 (menaquinone-7) on bone loss in ovariectomized (OVX) rats was investigated. OVX rats were freely given experimental diets containing menaquinone-4 (MK-4; 12mg/100g diet) or menaquinone-7 (MK-7; 18.1mg/100g diet) for 24 days; MK-4 and MK-7 were equal in molar concentrations. This feeding caused a remarkable increase of MK-4 and MK-7 concentrations in the serum and femur of OVX rats. OVX-induced decrease in the femoral dry weight and femoral calcium content was prevented by the feeding of dietary MK-4 or NK-7. In separate experiments, OVX rats were freely given experimental diets containing the fermented soybean (natto; including 9.4 microg MK-7/100g diet) without or with added MK-7 (37.6 microg/100g diet) for 77 days. Feeding produced a significant elevation of MK-4 and MK-7 concentrations in the serum of OVX rats. In this case, a significant increase in the femoral MK-4 content was observed but MK-7 was not detected in the femoral tissues. OVX-induced decreases in the femoral dry weight and femoral calcium content were significantly prevented by the feeding of diets containing natto with MK-7 added (37.6 microg/100g diets). This study demonstrates that the intake of dietary MK-7 has a preventive effect on bone loss caused by OVX. This effect may be partly caused by MK-4, which is formed by degradation of MK-7.

Animals↗
PubMed1999

Prevalence and clinical characteristics of TT virus (TTV) in patients with sporadic acute hepatitis of unknown etiology.

BACKGROUND/AIMS: Recently, a novel DNA virus was isolated from the serum of a patient with post-transfusion non-A-G hepatitis and named TT virus. The aim of this study was to determine the prevalence and clinical characteristics of TT virus infection in patients with sporadic acute hepatitis of unknown etiology. METHODS: TT virus was investigated in the serum of 66 patients with sporadic acute hepatitis non-A-G and 50 healthy controls by semi-nested PCR with previously published primers. RESULTS: TT virus was detected in 17 (26%) of the 66 patients with sporadic acute hepatitis non-A-G and in a slightly higher rate (34%,17/50) in the control group. No significant differences in alanine aminotransferase or bilirubin concentrations were observed between the groups of patients with or without TT virus infection. Eighty per cent (12/15) of patients for whom follow up was possible had persistent viremia from 4 to 36 months, and 67% (8/12) of these patients had already normalized their levels of alanine aminotransferase. A phylogenetic tree constructed by the Neighbor Joining Method revealed that all isolates in this study were grouped within genotype 1a and 1b, without showing any association between genetic type and development of hepatic disease. CONCLUSIONS: Our results suggest that TT virus DNA is present not only in patients with sporadic acute hepatitis non-A-G but also in a large proportion of the general population. This virus was not likely to be the causative agent of hepatitis among the patients in this study.

Acute Disease↗
PubMed1999

Stimulatory effect of zinc acexamate administration on fracture healing of the femoral-diaphyseal tissues in rats.

The effect of zinc acexamate on fracture healing of the femoral-diaphyseal tissues in rats was investigated in vivo. Zinc acexamate (0.3 and 10.0 mg Zn/100 g body weight per day) was orally administered to rats (4 weeks old) surgically fractured the femoral diaphysis for 14 to 28 days. Calcium content and alkaline phosphatase activity in the femoral-diaphyseal tissues were significantly decreased in rats with fracture healing, while bone acid phosphatase activity and protein content were markedly increased. The administration of zinc acexamate (10.0 mg Zn/100 g) for 28 days caused a significant increase in calcium content, alkaline and acid phosphatases activities, protein and deoxyribonucleic acid (DNA) contents in the femoral-diaphyseal tissues of rats with fracture healing. With the lower dose (3.0 mg Zn/100 g), zinc compound had a partial effect on bone components. Femoral mineral density in rats with fracture healing was significantly increased by the administration of zinc acexamate (10.0 mg Zn/100 g) for 28 days. Femoral-diaphyseal zinc content was significantly decreased in rats with fracture healing. This decrease was completely restored by the administration of zinc acexamate (10.0 mg Zn/100 g) for 28 days. The present study suggests that the supplement of zinc compound stimulates fracture healing of the femoral-diaphyseal tissues in rats.

Acid Phosphatase↗
PubMed1999

An emergency balloon occlusion system for a rotary blood pump left ventricular assist system.

A fatal outcome is expected in a left ventricular assist system (LVAS) utilizing a rotary blood pump if there is no mechanism to prevent the backflow from the aorta to the heart in the case of acute pump failure. To solve this problem, a passive mechanical clamping system at the outflow graft of a rotary blood pump was developed together with Fuji Systems, Inc., Yokohama, Japan. The system consisted of an emergency clamp port and an occlusion balloon. The balloon was fixed around the outlet graft of the LVAS. In an in vitro study, a fail-safe clamping operation with 2 ml saline injection under 7 L/min flow against 140 mm Hg pressure reduced the flow to 0.5 L/min while the pressure in the system increased to 190 mm Hg. The systems were also applied to 2 in vivo LVAD studies. When the pumps were stopped, there were approximately 3.0 L/min regurgitant flows. The balloon occluder prevented this regurgitant flow effectively against a 100/80 mm Hg arterial pressure. In conclusion, this emergency balloon occlusion system is relatively easy to operate and will work efficiently in all possible clinically encountered malfunctions of the rotary blood pump LVAS.

Animals↗
PubMed1999

A Japanese case of dengue fever with lymphocytic vasculitis: diagnosis by polymerase chain reaction.

A 37-year-old Japanese male was admitted to Nagasaki University Hospital with abrupt onset of biphasic fever, general malaise and myalgia 9 days after coming back to Japan from Manila. He developed a rubella like erythematous rash 3 days after admission and purpuric eruption one week after admission. A biopsied specimen from the purpura revealed lymphocytic vasculitis with T cell dominance and without immunoglobulin or complement deposition around the blood vessels. RT-PCR analysis on peripheral blood mononuclear cells using dengue virus specific primers confirmed the diagnosis of type 3 dengue fever. PCR analysis using virus specific primers is a rapid and valuable method for making a correct diagnosis of dengue fever.

Adult↗