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Biomedical subjects

M Kurokawa

Publications and source records attributed to M Kurokawa.

At least 37 records · Page 2Linked to original sources
PubMed2002

Reverse seroconversion of hepatitis B virus after hematopoietic stem cell transplantation.

Hepatitis B virus (HBV) reactivation in patients previously positive for hepatitis B surface antibody (HBsAb), so-called reverse seroconversion, has been considered to be a rare complication after hematopoietic stem cell transplantation (HSCT). We experienced two patients who developed reverse seroconversion among nine who were HBsAb positive and Hepatitis B core antibody (HBcAb) positive before HSCT; one after autologous bone marrow transplantation (BMT) and another after allogeneic peripheral blood stem cell transplantation (PBSCT). We reviewed the literature and considered that reverse seroconversion of HBV after HSCT is not uncommon among HBsAb positive recipients. The use of corticosteroids, the lack of HBsAb in donor, and a decrease in serum HBsAb and HBcAb levels may predict reverse seroconversion after HSCT.

Adrenal Cortex Hormones↗
PubMed2001

Requirement of phospholipase Cdelta4 for the zona pellucida-induced acrosome reaction.

Several phospholipase C (PLC) isoforms have been found in male and female mammalian gametes, and splicing isoforms of PLCdelta4 are predominantly expressed in testis. Here we report that male mice in which the PLCdelta4 gene had been disrupted either produced few small litters or were sterile. In vitro fertilization studies showed that insemination with PLCdelta4-/- sperm resulted in significantly fewer eggs becoming activated and that the calcium transients associated with fertilization were absent or delayed. PLCdelta4-/- sperm were unable to initiate the acrosome reaction, an exocytotic event required for fertilization and induced by interaction with the egg coat, the zona pellucida. These data demonstrate that PLCdelta4 functions in the acrosome reaction that is induced by the zona pellucida during mammalian fertilization.

Acrosome↗
PubMed2001

The corepressor CtBP interacts with Evi-1 to repress transforming growth factor beta signaling.

Evi-1 is a zinc finger nuclear protein whose inappropriate expression leads to leukemic transformation of hematopoietic cells in mice and humans. This was previously shown to block the antiproliferative effect of transforming growth factor beta (TGF-beta). Evi-1 represses TGF-beta signaling by direct interaction with Smad3 through its first zinc finger motif. Here, it is demonstrated that Evi-1 represses Smad-induced transcription by recruiting C-terminal binding protein (CtBP) as a corepressor. Evi-1 associates with CtBP1 through one of the consensus binding motifs, and this association is required for efficient inhibition of TGF-beta signaling. A specific inhibitor for histone deacetylase (HDAc) alleviates Evi-1-mediated repression of TGF-beta signaling, suggesting that HDAc is involved in the transcriptional repression by Evi-1. This identifies a novel function of Evi-1 as a member of corepressor complexes and suggests that aberrant recruitment of corepressors is one of the mechanisms for Evi-1-induced leukemogenesis.

Alcohol Oxidoreductases↗
PubMed2001

Mutations of the Smad4 gene in acute myelogeneous leukemia and their functional implications in leukemogenesis.

The Smad family proteins are critical components of the transforming growth factor (TGF)-beta signaling pathway. TGF-beta is a multipotent cytokine that elicits many biological functions. In particular, TGF-beta exhibits effects on the cell cycle manifested by G1-phase arrest, differentiation, or apoptosis of several target cells, suggesting that disruption of TGF-beta signaling pathway could be involved in cancer formation. Here we show one missense mutation of the Smad4 gene in the MH1 domain (P102L) and one frame shift mutation resulting in termination in the MH2 domain (Delta(483 - 552)) in acute myelogeneous leukemia. Both of the mutated Smad4 proteins lack transcriptional activities. Concomitant expression of the P102L mutant with wild-type Smad4 inactivates wild-type Smad4 through inhibiting its DNA-binding ability. The Delta(483 - 552) mutant blocks nuclear translocation of wild-type Smad4 and thus disrupts TGF-beta signaling. This is the first report showing that mutations in the Smad4 gene are associated with the pathogenesis of acute myelogeneous leukemia and the obtained results should provide useful insights into the mechanism whereby disruption of TGF-beta signaling pathway could lead to acute myelogeneous leukemia. Oncogene (2001) 20, 88 - 96.

Animals↗
PubMed2001

Construction of Oka varicella vaccine expressing human immunodeficiency virus env antigen.

Oka varicella vaccine has been used to confer active immunity to varicella-zoster virus (VZV) in healthy and immunocompromised hosts. Based on its attenuated nature, Oka varicella vaccine expressing human immunodeficiency virus (HIV) env antigen was constructed by inserting the HIVenv gene into the viral genome and its immunogenicity was assessed in guinea pigs. The HIVenv gene encoding 296-463 amino acids was inserted between the sequences of the hepatitis B surface antigen and the thymidine kinase gene of the cloned plasmid and the recombinant virus was isolated by cotransfection of the chimeric plasmid with viral DNA. Insertion of the HIVenv gene into the viral genome was confirmed by PCR and sequencing of the viral genome of the recombinant virus. The recombinant virus expressed 30k HIVenv fusion protein in its infected cells. In guinea pigs, immunization with the recombinant virus induced an antibody response to both the HIV antigen and the V3 peptide of gp120 as well as VZV gE:gI. Cell-mediated immunity to the HIV antigen and gE:gI was assessed by the cutaneous reaction representing delayed type hypersensitivity. Immunized guinea pigs responded well to both the HIV antigen and gE:gI. Thus the recombinant Oka varicella vaccine expressing the HIVenv antigen induced both a humoral and cell-mediated immunity to the HIV antigen similar to VZV as Oka varicella vaccine induces humoral and cell-mediated immunity to VZV in the vaccinees. This recombinant Oka varicella vaccine expressing the HIVenv antigen may be evaluated for its immunogenicity as one of the AIDS vaccine candidates.

AIDS Vaccines↗
PubMed2001

In vivo antiviral activity of Stephania cepharantha against herpes simplex virus type-1.

The antiviral activity of a MeOH extract of Stephania cepharantha (root tubers), its CHCl3-soluble fraction (alkaloid fraction) and the major alkaloid FK-3000 (1) were investigated in BALB/c mice cutaneously infected with HSV-1 strain 7401H. At doses of 125 and 250 mg/kg body weight, p.o., the MeOH extract significantly delayed skin lesion on score 2 (vesicles in the local region), limited the development of further lesions on score 6 (mild zosteriform lesion) and prolonged the mean survival time of HSV-1 infected mice. After p.o. administration of the CHCl3-soluble fraction at doses of 25 and 50 mg/kg or FK-3000 (1) at 10 and 25 mg/kg, similar results were obtained. Although the alkaloid improved the survival of infected mice, it had a narrow therapeutic index.

Alkaloids↗
PubMed2001

Reconstruction of breast using a laser lithographic model: a case report.

A three-dimensional laser scanner enables the measurement of surface data from objects with no contact, both quickly and in three dimensions. A 40-year-old woman with a right breast cancer had undergone a simple mastectomy. The surface of the chest was then measured with the non-contact three-dimensional laser scanner. Using the mirror image of data obtained by the same system, a mask-like model of the breast was made using laser lithography technology. This model was used for reconstruction of the breast after mastectomy. It was effective in determining the position and form of the breast which was to be repaired.

Adult↗
PubMed2001

Oncogenic mechanisms of Evi-1 protein.

Although Evi-1 is thought to promote growth or block differentiation in some cell types, its biological functions have not been elucidated. To explore the mechanisms underlying Evi-1-induced oncogenesis, we investigated whether Evi-1 affects the signaling of transforming growth factor beta (TGF-beta), which inhibits proliferation of a wide range of cell types and is one of the most studied growth regulatory factors. We demonstrated that Evi-1 represses TGF-beta signaling and antagonizes its growth-inhibitory effects. Two separate regions of Evi-1 are responsible for this repression, one of which is the first zinc-finger domain. Through this domain, Evi-1 physically interacts with Smad3, an intracellular mediator of TGF-beta signaling, thereby suppressing the transcriptional activity of Smad3. These results define a novel function of Evi-1 as a repressor of signaling components of TGF-beta. We also demonstrated that Evi-1 represses Smad-induced transcriptional activation by recruiting CtBP as a corepressor. Evi-1 associates with CtBP1 through one of the CtBP-binding consensus motifs within the region from amino acid 544 to 607, and this association is required for the efficient inhibition of TGF-beta signaling. A specific histone deacetylase (HDAc) inhibitor, trichostatin A (TSA), alleviates Evi-1-mediated repression of TGF-beta signaling, suggesting that HDAc is involved in transcriptional repression by Evi-1. This identifies a novel function of Evi-1 as a member of corepressor complexes and suggests that aberrant recruitment of corepressors is one of the mechanisms involved in Evi-1-induced leukemogenesis. These results indicate that specific HDAc inhibitors may be useful in the treatment of Evi-1-induced neoplastic tumors, including myeloid leukemias.

Animals↗
PubMed2001

Effect of immunity on gene delivery into anterior horn motor neurons by live attenuated herpes simplex virus vector.

Efficient and prolonged foreign gene expression has been demonstrated in the bilateral anterior horn motor neurons of the spinal cord by intramuscular inoculation with attenuated herpes simplex virus (HSV) expressing latency associated transcript promoter-driven beta-galactosidase (betaH1). To examine the effect of immunity on the gene delivery, betaH1 was applied in rats immunized subcutaneously or intramuscularly with the parent HF strain. Rats were immunized subcutaneously with HF strain and 28 days later when the high antibody titer was maintained, betaH1 was inoculated into the right gastrocnemius muscle. Second, 35 days after inoculation with HF strain into the right gastrocnemius muscle, betaH1 was inoculated at the same site. In both ways of immunization, immunity did not abolish or prevent the transgene expression in the anterior horn motor neurons, but attenuated the range and the number of the beta-galactosidase-positive neurons from about 85% to 50-65% on 28 days after inoculation with betaH1. However, beta-galactosidase activity was observed in a wide range of the bilateral anterior horn motor neurons without significant pathological changes. These findings support the feasibility of the attenuated HSV vector in gene delivery into the central nervous system, even in the presence of immunity.

Animals↗
PubMed2001

Eccrine poromas in a patient with mycosis fungoides treated with electron beam therapy.

We describe a 72-year-old man with mycosis fungoides (MF) followed up at our hospital for more than 20 years, who has developed 14 eccrine poromas (EPs) in the past 12 years. Twelve of these tumours were ascertained as EP histopathologically without any findings of malignancy and the other two were clinically diagnosed and are not yet resected. To our knowledge, this is the first case report of MF complicated with multiple EPs. In our patient, all EPs arose in skin areas previously irradiated with an electron beam for the treatment of MF, suggesting that electron beam irradiation might have an effect on the development of EPs.

Acrospiroma↗
PubMed2001

Paired cloning of the T cell receptor alpha and beta genes from a single T cell without the establishment of a T cell clone.

T cell receptors, which recognize antigen peptides on MHC molecules, are essential probes for the analysis of T cell antigen specificity. The identification of paired T cell receptor (TCR) chains, alpha/beta or gamma/delta, usually requires the establishment of T cell clones, which is not always available. In this study, we tried, as an alternative method, the paired cloning of TCR alpha/beta genes directly from a single T cell. T cells were sorted as a single cell from which RNA was extracted. Then, TCR alpha/beta CDR3 regions were amplified from the single cell-derived cDNA by reverse transcriptase-polymerase chain reaction to determine their sequences. We successfully identified pairs of TCR alpha/beta genes, and reconstructed the TCR molecule by a bacterial expression system. This strategy makes it possible to obtain recombinant TCR molecules from a single T cell without cellular cloning and promotes the investigation of T cell antigen specificity.

Cell Differentiation↗
PubMed2001

Suppressive effects of anti-allergic agent suplatast tosilate (IPD-1151T) on the expression of co-stimulatory molecules on mouse splenocytes in vivo.

The effects of IPD-1151T on the expression of co-stimulatory molecules, CD40, CD80 and CD86, were investigated in vivo using mice with allergic disorders. BALB/c mice were immunized intraperitoneally with two doses of dinitrophenylated ovalbumin (DNP-OVA) at 1-week intervals. These mice then were treated intraperitoneally with 100 microg/kg of IPD-1151T once a day for 14 days, starting 7 days after the first immunization. On day 21, some mice were challenged intraperitoneally with DNP-OVA and the other mice were not challenged. All mice were autopsied on day 22 and assayed for immunoglobulin E, interleuken (IL)-4 and IL-5 productions following DNP-OVA immunization. The intraperitoneal treatment with IPD-1151T strongly suppressed immunoglobulin E contents in serum, which were enhanced by DNA-OVA immunization. IPD-1151T also caused a decrease in both IL-4 and IL-5 levels in splenic lymphocytes. We next examined the influence of IPD-1151T on co-stimulatory molecule expression on splenic lymphocytes. IPD-1151T caused suppression of CD40 and CD86 expression; however, the treatments did not affect CD80 expression.

Animals↗
PubMed2001

[Evaluation of immunochromatography method for rapid detection of Shigatoxin].

The Shigatoxin detection kit based on the immunochromatography system is commercially available. To obtain the identification result rapidly, we devised the improved method (ICG-Imp) replaced to an original method (ICG). Modification provided that Shigatoxins extracted directly from the strains grown on TSI medium without centrifugation. ICG-Imp was compared with ICG, RPLA and PCR. Comparing with RPLA, the sensitivity, specificity, and concordance rate of Shigatoxin 1 showed 77.5, 100 and 90.5%, respectively on ICG, 93.8, 100 and 97.4%, respectively on ICG-Imp, and 100, 99.1 and 99.5%, respectively on PCR. On the other hand, the patterns of Shigatoxin 2 showed 95.3, 100 and 96.3%, respectively on ICG, 100, 100, and 100%, respectively on ICG-Imp, and 100, 100 and 100%, respectively on PCR. The time required from TSI medium to the final result are 24 h, 30-60 min, 48 h, and 6 h, respectively by ICG, ICG-Imp, RPLA, and PCR. It seems that the ICG-Imp is recommended for the identification by means of the accuracy and rapidness.

Centrifugation↗
PubMed2001

[Surveillance of various enteropathogenic bacteria from diarrheal cases during 1989-1999 in Kobe City].

Incidence of various enteropathogenic bacteria was examined from diarrheal faecal samples that were collected from the patients of Kobe City General Hospital and some station hospitals (23,862), and from overseas travelers (2,855) over a period of decade (1989-1999) in Kobe. A total of 1,580 strains were isolated from domestic and 331 strains from overseas travelers. The results are as follows. 1) Thirteen kinds of enteropathogenic bacteria were isolated from domestic diarrheal cases (6.6%). Salmonella was the most predominant bacteria followed by Campylobacter, Vibrio parahaemolyticus, enteropathogenic Escherichia coli and Shigella. 2) Eleven kinds of enteropathogenic bacteria were isolated from overseas diarrheal travelers (11.6%). The most frequently isolated species was Salmonella, followed by Vibrio parahaemolyticus, Shigella and Plesiomonas shigelloides. 3) Of Salmonella strains isolated from domestic and overseas diarrheal cases, serovar Enteritidis was the most predominant. Other frequent serovars in both cases were Typhimurium, Tennessee, Hadar, Infantis, Blockley and Montevideo. 4) Antibiotics resistant rate of the isolated Salmonella strains was 42.6% for domestic samples and 29.3% for overseas diarrheal cases. In domestic cases. Enteritidis was resistance to streptomycin only and the multiple antibiotic resistance was observed in Typhimurium serovars. In overseas samples, the multiple antibiotic resistance was seen in a few Typhimurium, Anatum and Blockley strains. 5) Among Shigella, S. sonnei was isolated from both domestic and overseas cases. The frequency of acquiring infection was the highest in India, followed by Indonesia, Thailand and Nepal. 6) With reference to the incidence of the members of the genus Vibrio, Aeromonas and Plesiomonas, V. parahaemolyticus were abundant from domestic samples where as V. parahaemolyticus, P. shigelloides, Vibrio cholerae non-O1 and Vibrio cholerae O1 were isolated more frequently from overseas samples. The frequency of acquiring infection was the highest in Thailand, followed by Indonesia and India.

Bacteria↗
PubMed2001

Effect of long-term, low-dose acyclovir suppressive therapy on susceptibility to acyclovir and frequency of acyclovir resistance of herpes simplex virus type 2.

We have examined the susceptibility to acyclovir and frequency of acyclovir-resistant viruses in herpes simplex virus type (HSV) 2 clones isolated directly from genital lesions of 11 patients who had taken suppressive therapy (200 mg/day) for 1-9 years and 15 patients naive to acyclovir. Suppressive therapy significantly reduced the incidence of recurrence and the severity of the skin lesions. HSV samples from genital lesions were directly inoculated into Vero cells, and viral clones were isolated in the absence and presence of 10 microg/ml acyclovir. Five-hundred-and-ninety-two clones, isolated in the absence of acyclovir, were subjected to the acyclovir susceptibility test, and 155 clones isolated in the presence of acyclovir were analysed for the mechanisms of resistance to acyclovir. There were no significant differences in the susceptibility to acyclovir, the frequency of acyclovir-resistant virus and the ratio of thymidine kinase-deficient viruses in acyclovir-resistant viruses between the two groups. The frequency of acyclovir-resistant clones was about three per 10000 plaque forming units (PFU), and genital lesions contained up to 3x10(6) PFU of replicating virus in the specimens from the patients with genital herpes with or without acyclovir-suppressive therapy. Thus, the low dose of acyclovir suppressive therapy did not affect the susceptibility to acyclovir or increase the frequency of acyclovir-resistant viruses in the genital lesions.

Acyclovir↗
PubMed2001

VLCD-induced weight loss improves heart rate variability in moderately obese Japanese.

To evaluate the effects of weight reduction on the autonomic nervous system in obese patients, we investigated heart rate variability (HRV) based on 24-hr ambulatory electrocardiogram (ECG) recordings before and after weight reduction. To aim for weight reduction, 16 obese patients were treated with the very-low-calorie conventional Japanese diet (VLCD-CJ) therapy combined with behavior therapy. Percent weight reduction was 17.8% +/- 1.5% (means +/- SEM), but mean blood pressure did not change significantly after VLCD-CJ therapy. The mean normal R-R interval (mNN) of the 24-hr ECG and all other five time-domain indices increased after weight reduction. Spectral analysis revealed that weight reduction increased the high frequency (HF) component, but decreased the ratio of low to high (LF/HF) components. Rate of change in mNN or HF correlated positively with reduction rate of body mass index, but not that in LF/HF. Analysis of daily fluctuations in each HRV parameter showed that significant improvement after weight loss occurred mainly during the nocturnal period, but an HF component was improved throughout the day and night periods. These findings indicate that functional impairment of the autonomic nervous system in obese subjects, particularly in the nocturnal period, is improved by effective weight reduction after VLCD-CJ therapy.

Adult↗
PubMed2001

Effect of temocapril hydrochloride on serum lipid levels in patients with hypertensive type 2 diabetes mellitus.

The effect of angiotensin converting enzyme inhibitor, temocapril hydrochloride on the serum lipoproteins, and especially on the size of low density lipoproteins (LDL) of hypertensive diabetic patients, were studied. Temocapril hydrochloride (5 mg/day) was administered to 32 hypertensive type 2 diabetes patients for 16 weeks. During treatment, systolic and diastolic blood pressures decreased significantly from 162/95 mmHg to 138/76 mmHg at 16 weeks (p<0.001), and serum levels of total cholesterol (TC) and low density lipoprotein cholesterol (LDL-C) showed significant reduction, but those of HbA1c, triglycerides (TG) and high density lipoprotein cholesterol (HDL-C) showed no significant changes. LDL particle size evaluated by polyacrylamide gel disc electrophoresis was normalized from small size. It is concluded that temocapril hydrochloride favorably affects the serum lipoprotein metabolism of hypertensive type 2 dependent diabetes mellitus patients.

Antihypertensive Agents↗