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Yoshiyuki Takahashi

Publications and source records attributed to Yoshiyuki Takahashi.

At least 19 recordsLinked to original sources
PubMed2026

Feasibility and Efficacy of Lorlatinib in Japanese Patients With Relapsed/Refractory ALK-Aberrant Neuroblastoma.

Lorlatinib, a third-generation ALK inhibitor, was administered off-label to five heavily pretreated patients with relapsed or refractory ALK-aberrant neuroblastoma. ALK alterations included F1174L, R1275Q, BEND5::ALK fusion, and ALK amplification; three patients had MYCN amplification. Best responses were three partial responses and two disease progressions. The longest progression-free survival (6.7 months) occurred in a patient with F1174L and non-amplified MYCN, whereas rapid progression was observed in two MYCN-amplified cases. Lorlatinib was generally well tolerated with manageable adverse events. These findings suggest that lorlatinib is a feasible therapeutic option in ALK-aberrant neuroblastoma and that clinical heterogeneity in treatment response warrants further investigation.

Humans↗
PubMed2026

Comprehensive Viral Detection and Profiling of Plasma Cell-Free RNA in Patients With Suspected Hemophagocytic Lymphohistiocytosis.

Hemophagocytic lymphohistiocytosis (HLH) is a severe, rapidly progressive disease. While viral infection is considered a common etiology of pediatric HLH, specific causative viruses other than the Epstein-Barr virus (EBV) have been rarely identified. This study utilized metagenomic next-generation sequencing (NGS) to identify potential causative pathogens in plasma samples from 17 pediatric patients with suspected HLH. Additionally, one case each of confirmed EBV- and cytomegalovirus (CMV)-associated HLH was analyzed for methodological validation. Plasma cell-free RNA (cfRNA) profiling was performed using NGS data to assess the host transcriptome response. Significant viral reads of human herpesvirus-6B, human herpesvirus-7, and Hubei reo-like virus (HRLV) 14 were detected using metagenomic NGS in one patient each. Plasma cfRNA profiles from five patients with viral infection (including EBV and CMV) were compared to those of 14 patients without viral infection. By comparing the two patient groups, 1053 differentially expressed genes were identified. The gene ontology (GO) term of "adaptive immune response" (GO: 0002250) was significantly enriched among upregulated genes in the virus-positive group. Furthermore, an isolated cluster consisting specifically of mitochondrial RNAs, was identified in the upregulated genes of the virus-positive group. Using metagenomic NGS, several candidate viral pathogens were identified in patients with suspected infection-related HLH. The viral genome of HRLV 14, previously undetected in human clinical samples, was identified in one patient. The results from plasma cfRNA profiling suggest that mitochondrial RNAs may reflect the underlying pathogenesis of virus-associated HLH and have potential utility as disease biomarkers.

Humans↗
PubMed2025

Plasma Proteomic Profiles of Pediatric Patients With Human Herpesvirus 6B Encephalitis Following Umbilical Cord Blood Transplantation.

Human herpesvirus 6B (HHV-6B) encephalitis is a rare but severe complication of hematopoietic cell transplantation. This study investigated the pathogenesis of HHV-6B encephalitis by comparing plasma proteomic profiles of four pediatric patients with HHV-6B encephalitis to three with asymptomatic HHV-6B reactivation following umbilical cord blood transplantation (UCBT). Plasma proteomic profiling was conducted using liquid chromatography-mass spectrometry. Overall, 260 proteins were identified and quantified in plasma samples. At the onset of HHV-6B encephalitis and asymptomatic reactivation, 20 and 24 proteins, respectively, were significantly upregulated compared to their respective pre-onset levels. Of these, 11 proteins were uniquely upregulated in HHV-6B encephalitis. S100-A9 and S100-A8 were the most and second-most upregulated proteins in HHV-6B encephalitis, respectively. Elevated plasma S100A8/A9 heterodimer levels were confirmed via enzyme-linked immunosorbent assay in three of the four patients with HHV-6B encephalitis. Pathway analysis identified neutrophil degranulation as the most enriched category among upregulated proteins in HHV-6B encephalitis. Additionally, proteins related to the protein-lipid complex remodeling pathway were more prominently upregulated in HHV-6B encephalitis than in asymptomatic reactivation. Proteomic analysis revealed distinct plasma protein profiles between HHV-6B encephalitis and asymptomatic HHV-6B reactivation in pediatric UCBT recipients. The inflammatory response mediated by S100A8/A9 proteins may play a critical role in the pathogenesis of HHV-6B encephalitis. These findings indicate that proteomic analysis may provide novel insights into the host response to HHV-6B reactivation and the subsequent development of HHV-6B encephalitis.

Humans↗
PubMed2006

Metabolic profiles in ovulatory and anovulatory primiparous dairy cows during the first follicular wave postpartum.

Metabolic hormones affect ovarian function in the cow. However, the relationship between metabolic factors and ovarian function is not clear in the postpartum primiparous cow because they are still growing. The aim of the present study was to investigate in detail the time-dependent profile of the metabolic hormones, metabolites, and milk yields of ovulatory and anovulatory primiparous cows during the first follicular wave postpartum. We used 16 primiparous Holstein cows and obtained blood samples for the profiles of metabolites (glucose; non-esterified fatty acid, NEFA; ketone body; total cholesterol; and aspartate aminotransferase), metabolic hormones (growth hormone, GH; insulin-like growth factor-I, IGF-1; and insulin), and progesterone every other day from 1 to 21 days postpartum. In addition, all ovaries were observed using ultrasound. Dairy milk yield was recorded during the experimental period. In all cows, the first follicular wave postpartum was observed and 6 of the cows ovulated. The plasma glucose (P<0.0001) and IGF-1 (P<0.001) concentrations were lower and the plasma NEFA (P<0.0001) and ketone bodies (P<0.0001) concentrations and daily milk yield (P<0.0001) were higher in the anovulatory cows compared to the ovulatory cows. However, the GH levels, which enhance lipolysis for milk production, insulin and other metabolites did not differ between the two groups. In conclusion, the present study suggests that anovulation of the dominant follicle during the first follicular wave postpartum in primiparous cows is induced by low IGF-1 levels that are similar to those of multiparous cows. In addition, anovulatory cows are likely to mobilize body fat stores for milk production more easily than ovulatory cows.

Animals↗
PubMed2006

Rapid sex chromosomal chimerism analysis in heterosexual twin female calves by Loop-mediated Isothermal Amplification.

We attempted to apply an embryo sexing kit with Loop-mediated Isothermal Amplification (LAMP) to sex chromosomal chimerism analysis in heterosexual twin female calves. Peripheral blood was used for the amplification of male-specific DNA, derived from XY leukocytes. When blood samples were diluted 1:1000 in LAMP reaction mixture, hemoglobin or blood coagulation did not influence the turbidity measurement of the reaction mixture for detection of amplified DNA. This procedure detected the existence of XY leukocytes of 0.01% in female blood. Furthermore, all heterosexual twin female calves, bearing sex chromosomal chimerism based on karyotyping and PCR, showed male-specific DNA from peripheral blood by LAMP. These results indicated that the embryo sexing kit with LAMP was available for sensitive detection of sex chromosomal chimerism. This procedure made it possible to detect easily Y-chromosome specific DNA in a short interval compared with PCR, and was convenient for field application of freemartin diagnosis.

Animals↗
PubMed2006

Impact of pretilachlor herbicide and pyridaphenthion insecticide on aquatic organisms in model streams.

To detect the impact of pesticides on aquatic organisms, model streams (3m wide, 20 m long) were established in paddy field in Japan. More than 100 species of aquatic organisms were generated in the model streams. Field tests with pretilachlor herbicide and pyridaphenthion insecticide were carried out in the streams for 3 yr (2001-2003). Exposure of pretilachlor (max. 0.382 mg/L) showed little density changes in algae with a Bray-Curtis percent similarity in the range 81.6-93.3% for algae. Exposure to high concentrations (>0.1mg/L) of pyridaphenthion produced visible density reductions in Cladocera zooplankton species. Reduction of individual aquatic insects in the model streams by pyridaphenthion caused an increase of chlorophyll a greater than that of the control streams. The pesticides used showed no substantial differences in the ecosystems of model streams exposed to maximum environmental concentrations (e.g., 0.01 mg/L) detected in real rivers.

Acetanilides↗
PubMed2006

Rapid sexing of water buffalo (Bubalus bubalis) embryos using loop-mediated isothermal amplification.

Loop-mediated isothermal amplification (LAMP) is a novel DNA amplification method that amplifies a target sequence specifically under isothermal conditions. The objective of this study was to identify a Y chromosome-specific sequence in water buffalo and to establish an efficient procedure for embryo sexing by LAMP. The homologues of a Y chromosome-specific sequence, bovine repeat Y-associated.2, in swamp and river buffalo were cloned, and designated swamp buffalo repeat Y-associated.2 and river buffalo repeat Y-associated.2, respectively. Sexing by LAMP was performed using primers for swamp buffalo repeat Y-associated.2. A 12S rRNA was also amplified by LAMP as a control reaction in both male and female. The minimal amount of the template DNA required for LAMP appeared to be 0.1-10 pg. The sensitivity was further examined using swamp buffalo fibroblasts as templates. When fibroblasts were lysed with NaOH, the minimal cell number required for detection of both male-specific and male-female common DNA appeared to be two cells, whereas correct determination of sex could not be achieved using fibroblasts lysed by heat denaturation. Embryo sexing was also performed using blastomeres from interspecies nuclear transfer embryos. The sex determined by LAMP for blastomeres corresponded with the sex of nuclear donor cells in analyses using four or five blastomeres as templates. The LAMP reaction required only about 45 min, and the total time for embryo sexing, including DNA extraction, was about 1 h. In conclusion, the present procedure without thermal cycling and electrophoresis was reliable and applicable for water buffalo embryos.

Animals↗
PubMed2006

Cell labeling for magnetic resonance imaging with the T1 agent manganese chloride.

There is growing interest in using MRI to track cellular migration. To date, most work in this area has been performed using ultra-small particles of iron oxide. Immune cells are difficult to label with iron oxide particles. The ability of adoptively infused tumor specific T cells and N cells to traffic to the tumor microenvironment may be a critical determinant of their therapeutic efficacy. We tested the hypothesis that lymphocytes and B cells would label with MnCl2 to a level that would allow their detection by T1-weighted MRI. Significant signal enhancement was observed in human lymphocytes after a 1 h incubation with 0.05-1.0 mM MnCl2. A flow cytometry-based evaluation using propidium iodide and Annexin V staining showed that lymphocytes did not undergo apoptosis or necrosis immediately after and 24 h following a 1 h incubation with up to 1.0 mM MnCl2. Importantly, NK cells and cytotoxic T cells maintained their in vitro killing capacity after being incubated with up to 0.5 mM MnCl2. This is the first report to describe the use of MnCl2 to label lymphocytes. Our data suggests MnCl2 might be an alternative to iron oxide cell labeling for MRI-based cell migration studies.

Cell Movement↗
PubMed2006

Relationship between bovine oocyte morphology and in vitro developmental potential.

We investigated the relationship between the morphology of oocytes collected from small antral follicles and their developmental capacity. Immature oocytes were classified into seven groups and cultured in vitro for maturation (IVM), fertilization (IVF) and development to blastocysts (IVC). After IVF, sperm penetration and normal fertilization rates were higher in the oocytes whose cytoplasm appeared brown. The rate of polyspermy was highest in the oocytes whose cytoplasm was black. After IVC, the rates of cleavage and of development to the blastocyst stage were also higher in the brown oocytes. Although the oocytes with dark clusters in a pale cytoplasm showed lower cleavage rates, cleaved zygotes had high developmental rates the same as the oocytes with a brown cytoplasm. Transmission electron microscopy showed that the oocytes with a pale or black cytoplasm had organelles arranged differently from other oocytes before IVM. Most of the oocytes with a brown and homogeneous cytoplasm or small diameter had the characteristics of immature cytoplasm (large clusters of cortical granules) even after IVM. On the other hand, the brown oocytes with a dark zone at the periphery or with dark clusters showed the same arrangement of organelles as in vivo matured oocytes. The oocytes with a pale or black cytoplasm appeared to be degenerating and/or ageing. In conclusion, a dark ooplasm indicates an accumulation of lipids and good developmental potential, while a light-coloured ooplasm indicates a low density of organelles and poor developmental potential. A black ooplasm indicates ageing and low developmental potential.

Animals↗
PubMed2006

Intracytoplasmic sperm injection in the bovine induces abnormal [Ca2+]i responses and oocyte activation.

Fertilisation by intracytoplasmic sperm injection (ICSI), a technique that bypasses the membrane fusion of the gametes, has been widely used to produce offspring in humans and mice. Success with this technique has lent support to the hypothesis that in mammalian fertilisation, a factor from the sperm, the so-called sperm factor, is responsible for oocyte activation and that the fusion process is not involved in the generation of the hallmark [Ca2+]i signalling seen following fertilisation. However, the success of ICSI has largely eluded large domestic species, such as the bovine, porcine and equine, casting doubt on the current model of oocyte activation at fertilisation in these species. Using Ca2+ imagery and a series of treatments to manipulate the chemical structure of the sperm, we have investigated the early events of oocyte activation in response to ICSI in the bovine. Our results demonstrate, for the first time, that following ICSI, the majority of bovine oocytes are unable to mount [Ca2+]i oscillations, although, in few cases, the initiation of [Ca2+]i oscillations can occur in a manner indistinguishable from in vitro fertilisation. We also show that bull sperm possess a full complement of sperm factor. However, either the release and/or activation of the sperm factor are compromised after ICSI, leading to the delivery of a defective Ca2+ stimulus, which results in premature termination of embryo development.

Acrosome Reaction↗
PubMed2006

Sucrose-exposed chemically enucleated mouse oocytes support blastocyst development of reconstituted embryos.

This study was carried out to test the ability of sucrose-exposed chemically enucleated mouse oocytes to support the development of reconstituted embryos in vitro. Cumulus-enclosed germinal-vesicle-stage mouse oocytes were matured in vitro to metaphase I stage and were chemically enucleated with 50 microg mL(-1) etoposide in tissue culture medium 199. The chemically enucleated oocytes were grouped into two groups. Group I was exposed to 0.75 M sucrose and group II was not exposed to sucrose. The zonae pellucidae of the chemically enucleated oocytes were removed with acid Tyrode's solution (pH 2.7). They were then aggregated into couplets with karyoplasts from pronuclear-stage embryos using phytohemagglutinin-P. The couplets were electrically fused to form reconstituted embryos. The reconstituted embryos were activated with 7% ethanol and cultured in vitro in simplex optimisation medium to test their developmental ability to the blastocyst stage. Some of the reconstituted embryos that developed to the blastocyst stage were used for chromosome counts to test their ploidy. The results of the present study showed that chemically enucleated oocytes exposed to sucrose supported the development of reconstituted embryos to the blastocyst stage (21.5%), whereas those not exposed to sucrose did not. The chromosome counts showed that the reconstituted embryos had normal ploidy (40 chromosomes). It is concluded that sucrose exposure improves the quality of chemically enucleated mouse oocytes. Thus they can be used as recipients for mouse embryo cloning and nucleocytoplasmic interaction studies.

Animals↗
PubMed2006

Overcoming graft rejection in heavily transfused and allo-immunised patients with bone marrow failure syndromes using fludarabine-based haematopoietic cell transplantation.

Allogeneic haematopoietic cell transplantation (HCT) can cure a variety of non-malignant haematological disorders. Although transplant outcomes for selected patients with severe aplastic anaemia (SAA) and paroxysmal nocturnal haemoglobinuria (PNH) have improved, older age, allo-immunisation from transfusions, prior immunosuppressive therapy and a prolonged time from diagnosis to transplantation are associated with worse outcome. Because of its potent immunosuppressive effects, we investigated a fludarabine-based non-myeloablative conditioning regimen in patients with transfusion-dependent non-malignant haematological disorders at increased risk for graft rejection with conventional transplant conditioning. Twenty-six patients with transfusion dependent/anti-thymocyte globulin (ATG)-refractory SAA, PNH or pure red cell aplasia underwent HCT from a human leucocyte antigen (HLA)-compatible relative. Transplant conditioning consisted of cyclophosphamide (120 mg/kg) and fludarabine (125 mg/m2) with or without ATG. Ciclosporine, alone or combined with mycophenolate mofetil or methotrexate, was used as graft-versus-host disease (GVHD) prophylaxis. All patients achieved durable engraftment and transfusion-independence. Twenty-four of 26 patients are alive at a median of 21 months following transplantation. Although a high cumulative incidence of acute (65% grades II-IV, 54% grades III-IV) and chronic GVHD (56%) was observed, only one patient died from transplant-related causes (cumulative incidence 7%). These data show that HCT following fludarabine-based non-myeloablative conditioning results in durable engraftment and excellent survival in SAA and PNH patients at high risk for graft rejection.

Adolescent↗
PubMed2005

Potential relationship between normalization of endometrial epidermal growth factor profile and restoration of fertility in repeat breeder cows.

The present study characterized alterations of the endometrial epidermal growth factor (EGF) and examined potential relationships between normalization of the EGF and restoration of fertility in repeat breeder cows. In Experiment 1, endometrial tissues were obtained by biopsy on Days 3, 7 and 14 of the estrous cycle from 99 fertile dairy cows and normal ranges of uterine tissue EGF concentrations were determined. Then, eight fertile cows were examined for endometrial EGF concentrations on Days 3, 7 and 14 during the three consecutive estrous cycles. All eight cows had a normal EGF profile (EGF concentrations were within the normal ranges of all 3 days) in all three estrous cycles and endometrial EGF concentrations were similar among the three estrous cycles. In Experiment 2, 61 repeat breeder cows were examined EGF profile and 43 (70.5%) cows had altered EGF profiles compared with control profiles. A typical alteration was characterized by decreased concentrations on Days 3 and 14 and accounted for 86.0% of all alterations. When repeat breeder cows with altered EGF profiles (n=17) were left untreated, abnormality persisted in 14 (82.4%) cows at the second examination and only 3 animals became pregnant within the next two estrous cycles. Among 15 cows showing a typical alteration at the first examination, 11 (73.3%) cows had the same alteration until the third examination performed after two infertile inseminations following the second examination. When repeat breeder cows with altered EGF profiles (n=26) were given one of four therapeutic treatments, cows in which the EGF profile normalized after treatment had a greater pregnancy rate than those with altered profiles (11/14 animals versus 3/12 animals pregnant; P<0.05). In conclusion, suppressed endometrial EGF concentrations on Days 3 and 14 may be common alterations and persist between estrous cycles in repeat breeder cows. Potential relationship between normalization of the endometrial EGF profile and restoration of fertility was observed. Additional study to confirm results of the treatment is, however, necessary because the present study used a limited number of animals. Nevertheless, current data suggest that normalization of the EGF profile is one of the prerequisite factors to restore fertility.

Animals↗
PubMed2005

Safety and immunogenicity of gelatin-free varicella vaccine in epidemiological and serological studies in Japan.

Following gelatin-containing varicella vaccine (1994-1999: 1,410,000 distributed doses), 28 serious anaphylactic reactions and 139 non-serious allergic reactions were reported, with no serious and only five non-serious reactions following gelatin-free vaccine (1999-2000: 1,300,000 distributed doses). All nine sera available from children with serious reactions tested positive for gelatin-specific IgE, whereas 55 of the 70 available from those with non-serious reactions were positive, with one false positive. There was no correlation between gelatin-specific IgE antibody titers and severity of allergic reaction. Post-immunization anti-varicella antibody titers were comparable for both gelatin-free and gelatin-containing vaccine groups. The new gelatin-free varicella vaccine is thought to be safe, with similar immunogenicity to the earlier gelatin-containing vaccine.

Anaphylaxis↗
PubMed2005

Pharmacokinetic interactions of flunixin meglumine and enrofloxacin in dogs.

OBJECTIVE: To examine pharmacokinetic interactions of flunixin meglumine and enrofloxacin in dogs following simultaneously administered SC injections of these drugs. ANIMALS: 10 Beagles (4 males and 6 females). PROCEDURE: All dogs underwent the following 3 drug administration protocols with a 4-week washout period between treatments: flunixin administration alone (1 mg/kg, SC); simultaneous administration of flunixin (1 mg/kg, SC) and enrofloxacin (5 mg/kg, SC); and enrofloxacin administration alone (5 mg/kg, SC). Blood samples were collected from the cephalic vein at 0.5, 0.75, 1, 1.5, 2, 3, 5, 8, 12, and 24 hours following SC injections, and pharmacokinetic parameters of flunixin and enrofloxacin were calculated from plasma drug concentrations. RESULTS: Significant increases in the area under the curve (32%) and in the elimination half-life (29%) and a significant decrease (23%) in the elimination rate constant from the central compartment of flunixin were found following coadministration with enrofloxacin, compared with administration of flunixin alone. A significant increase (50%) in the elimination half-life and a significant decrease (21%) in the maximum plasma drug concentration of enrofloxacin were found following coadministration with flunixin, compared with administration of enrofloxacin alone. CONCLUSIONS AND CLINICAL RELEVANCE: The observed decrease in drug clearances as a result of coadministration of flunixin and enrofloxacin indicates that these drugs interact during the elimination phase. Consequently, care should be taken during the concomitant use of flunixin and enrofloxacin in dogs to avoid adverse drug reactions.

Animals↗