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Biomedical subjects

Y Miyagi

Publications and source records attributed to Y Miyagi.

At least 19 recordsLinked to original sources
PubMed2006

Novel heteroduplex method using small cytology specimens with a remarkably high success rate for analysing EGFR gene mutations with a significant correlation to gefitinib efficacy in non-small-cell lung cancer.

We conducted a feasibility study to examine whether small numbers of cancer cells could be utilised for analysis of the EGFR gene status using the loop-hybrid mobility shift assay, which is a modified heteroduplex technique. Cytology specimens obtained by transbronchial abrasion were successfully used for analysis of the EGFR gene status in 50 of 52 (96.2%) patients diagnosed with class V non-small-cell carcinoma. Furthermore, the relationship between the EGFR gene status and clinical outcome was analysed in 25 patients treated with gefitinib. Overall, 10 of 11 patients with EGFR mutations in exon 19 or 21 showed tumour regression with gefitinib treatment, compared to only two of 14 patients with wild-type EGFR. The response rate was significantly higher in the EGFR mutation group than in the wild-type EGFR group (90.9 vs 14.3%, P=0.00014). Logistic regression analysis revealed that EGFR mutations in cytology specimens represented an independent predictor of the gefitinib response. The overall and progression-free survivals were significantly longer in the EGFR mutation group than in the wild-type EGFR group (P<0.05). In conclusion, cytology specimens could be useful for analysing the EGFR status in the majority of patients with non-small-cell lung cancer to determine whether they are likely to benefit from gefitinib treatment.

Adult↗
PubMed2006

Aberrant trafficking of a proteolipid protein in a mild Pelizaeus-Merzbacher disease.

Pelizaeus-Merzbacher disease (PMD) is a rare X-linked leukodystrophy caused by proteolipid protein 1 (PLP1) gene mutations. Previous studies indicated that proteolipid proteins (PLPs) with disease-associated mutations are misfolded and trapped in the endoplasmic reticulum (ER) during transportation to the cell surface, which eventually leads to oligodendrocyte cell death in PMD. Here we report a PMD patient with a very mild phenotype carrying a novel mutation (485G-->T) in exon 4 of the PLP1 gene that causes a Trp(162)Leu substitution in the protein. We also investigated intracellular trafficking of this mutant PLP in COS-7 cells. Transiently transfected mutant PLP(W162L) fused to an enhanced green fluorescent protein (EGFP) or a short peptide tag was not carried to the plasma membrane. However, in contrast to previous studies, this mutant PLP was not retained in the ER, indicating an escape of the newly translated protein from the quality control machinery. We also found that the mutant PLP accumulated in the nuclear envelope (NE) in a time-dependent manner. This mutant PLP, with its distribution outside the ER and a very mild phenotype, supports the idea that accumulation of misfolded mutant protein in the ER causes the severe phenotype of PMD.

Animals↗
PubMed2006

Radioactivity thresholds for sentinel node biopsy in breast cancer.

AIMS: The aim of the present study is to clarify the level of radioactive lymph node should be biopsied after the most radioactive SN is removed. METHODS: SNB using radionuclide was performed in our hospital for 1179 primary breast cancers between April 2000 and October 2005; most (1177/1179) were performed successfully. Our criterion for harvesting SNs is to remove tissue until no radioactive site is present. The level of radioactivity and the order of removal of each lymph node were compared with pathologic results. RESULTS: More than 2 (overall average 1.9) radioactive SNs were biopsied in 686 of 1177 breasts. Cancer positive results were recorded for 142 breasts with multiple SNs. In 142 breasts, 64 showed metastasis to the most radioactive node only, 39 showed metastasis other than the most radioactive node only, and 39 showed the most radioactive node and other radioactive nodes. Moreover, if several other criteria were applied, false-positive cases were increased significantly. CONCLUSIONS: It is necessary to harvest radioactive lymph nodes other than the most radioactive. Moreover, efforts to remove every radioactive lymph node will minimize false-negative results.

Axilla↗
PubMed2006

Paradoxical discrepancy between the serum level and the placental intensity of PP5/TFPI-2 in preeclampsia and/or intrauterine growth restriction: possible interaction and correlation with glypican-3 hold the key.

There have been controversies whether maternal serum placental protein 5 (PP5)/tissue factor pathway inhibitor (TFPI)-2 is increased in the patients with preeclampsia and/or intrauterine growth restriction (IUGR). Here, we have estimated the serum PP5/TFPI-2 in these patients by a sandwich enzyme-linked immunosorbent assay with a newly developed monoclonal antibody, coupled with placental immunohistochemical studies of their placentae with semiquantitative scoring. Serum PP5/TFPI-2 level was significantly elevated only in the patients with preeclampsia alone (p=0.033), while PP5/TFPI-2 was detected significantly less intensely in the placentae of the same patients (p=0.035) in immunohistochemistry, as compared to Controls. A proteoglycan present on the placental villous surface, glypican-3, showed the same pattern of staining as PP5/TFPI-2, and there was a positive correlation (C.I.=0.506, p=0.004) between the immunohistochemical scores for these. Further experiments using HepG2 cells transfected with PP5/TFPI-2 suggested that glypican-3 could anchor PP5/TFPI-2 on the placental villi. A possibility that a decrease in glypican-3 in the placenta increases the outflow of PP5/TFPI-2, which in turn increases its serum level, was proposed. Preeclampsia and IUGR, often regarded to have the same pathological basis in common, showed distinct distributions of PP5/TFPI-2, which could be a clue to elucidate the pathogenesis of preeclampsia and IUGR.

Adult↗
PubMed2005

The effect of an old surgical scar on sentinel node mapping in patients with breast cancer: a report of five cases.

AIMS: To study the significance of lymphatic drainage disruption due to a surgical scar in sentinel node mapping (SNM) in breast cancer patients. METHODS: We reviewed patients with stage I breast cancer who had undergone SNM and had an old surgical scar in the ipsilateral breast. RESULTS: Of 534 breast cancer patients who had undergone SNM, five patients had an old scar in the ipsilateral breast. Inter-pectoral nodes, internal nodes, intramammary nodes, and contralateral axillary nodes were identified as sentinel nodes in three cases. In the remaining two cases, no sentinel lymph nodes were identified. CONCLUSIONS: An old surgical scar in the breast may cause lymphatic drainage disruption, resulting in abnormal radioactive colloid uptake during SNM.

Aged↗
PubMed2005

The pathologic impact of tacrolimus on protocol biopsy in renal transplant patients with basiliximab-based immunosuppression.

Forty-two ESRD patients underwent renal transplantation using basiliximab (mean age: 30.6 +/- 18.6 years at transplantation; male: 50%; ESRD duration: 51.6 +/- 13.0 months) between February, 2000 and July, 2003. All patients had a protocol biopsy on the day of transplant, on discharge from the hospital (35.5 +/- 13.2 days), and at 1 year after transplant. The immunosuppression included a calcineurin inhibitor, basiliximab, mycophenolate mofetil (MMF), and methylprednisolone. While 16 patients used tacrolimus (FK group: 29.4 +/- 16.6 years old), 26 patients used cyclosporine (CsA group: 31.4 +/- 20.1 years old). Protocol biopsies were graded according to the Banff 97 classification. The incidence of acute rejection episodes within 1 year was greater in the CsA (15%) than the FK group (6%). Serum creatinine at hospital discharge was similar (CsA: 1.01 +/- 0.59 mg/dL, FK: 0.97 +/- 0.49, p = .18); however creatinine at 1 year differed significantly (CyA: 1.22 +/- 0.88 mg/dL, FK: 0.92 +/- 0.39, P = .03). There was a trend toward an increase in the score of interstitial inflammations in the CsA group, while it remained constant in the FK cohort (P = .05 at 1 year between the two groups). Other pathologic scores (t, ci, ct, cv, ah) did not differ between the groups at 1 year. Although there were no differences in the demographics between the two groups, there were several trends toward better renal function in the FK group.

Antibodies, Monoclonal↗
PubMed2005

Association of MBL gene polymorphisms with major bacterial infection in patients treated with high-dose chemotherapy and autologous PBSCT.

A growing body of evidence indicates that genetic factors are involved in an increased risk of infection. We investigated whether mannose-binding lectin (MBL) gene polymorphisms that cause low levels of MBL are associated with the occurrence of major infections in patients, mainly bearing hematological malignancies, after high-dose chemotherapy (HDT) rescued by autologous peripheral blood stem cell transplantation (auto-PBSCT). A retrospective evaluation of 113 patients treated with HDT and auto-PBSCT revealed that the low-producing genotypes, B/B and B/LXA, were associated with major bacterial infection (P=0.0016, OR 7.9). We next performed a nation-wide large-scale study to assess the allele frequency of the MBL coding mutation in a total of 2623 healthy individuals in Japan. The frequency of allele B was estimated to be approximately 0.2, almost the same in seven different areas of Japan. This common occurrence suggests that MBL deficiency may play an important role in the clinical settings of immunosuppression.

Alleles↗
PubMed2005

Spatio-temporal analysis by voltage topography of ictal electroencephalogram on MR surface anatomy scan for the localization of epileptogenic areas.

A 15-year-old girl developed intractable epilepsy following a right transcallosal resection of the intraventricular teratoma. Magnetic resonance (MR) imaging showed a T (2)-prolonged subcortical lesion in the right frontal lobe as well as a residual intraventricular tumor. The integration of the voltage topography of ictal onset activities of the scalp-recorded electroencephalogram (EEG) and a surface anatomy scan of MR images clearly revealed the epileptogenic area on the cortex above the subcortical lesion, with the propagation pattern towards the frontopolar area. Excision of the epileptogenic cortex and underlying gliosis resulted in a successful cessation of the epilepsy. This non-invasive EEG technique provided useful information that accurately localized the epileptogenic area on a large structural abnormality without invasive intracranial electrocorticographic monitoring.

Adolescent↗
PubMed2004

Raised serum APRIL levels in patients with systemic lupus erythematosus.

OBJECTIVE: To determine whether serum levels of a proliferation-inducing ligand (APRIL) are raised in patients with systemic lupus erythematosus (SLE) and correlate with autoantibody titres or disease activity, or both. METHODS: Serum samples from 48 patients with SLE, 41 normal healthy subjects, and 21 patients with rheumatoid arthritis (RA) were assayed for APRIL by enzyme linked immunosorbent assay. Medical charts were retrospectively reviewed for autoantibody titres and immunoglobulin levels. Disease activity was assessed using the British Isles Lupus Assessment Group (BILAG) index. RESULTS: The APRIL levels in the serum samples from patients with SLE were significantly higher than in those from healthy controls and those from patients with RA. Serum APRIL levels did not correlate with serum IgG and IgM levels, but had a tendency to correlate with anti-double stranded DNA antibody titres. Moreover, serum APRIL levels correlated significantly with musculoskeletal manifestations among patients with SLE when assessed by the BILAG index. CONCLUSION: APRIL may be an important factor in raised autoantibody titres and musculoskeletal disease in patients with SLE. Patients with raised serum APRIL levels may be ideal candidates for therapeutic targeting of APRIL.

Adult↗
PubMed2002

Vim thalamotomy for Holmes' tremor secondary to midbrain tumour.

Holmes' (rubral or midbrain) tremor is an unusual combination of 2 Hz to 5 Hz rest, postural, and kinetic tremors of an upper extremity. This tremor has been considered to result from the lesions in the vicinity of the red nucleus in the midbrain. There has been no systematic analysis of the surgical target in the Holmes' tremor so far of nucleus ventrointermedius (Vim) or globus pallidus interna. This 26 year old man gradually developed a disabling midbrain tremor involving both the distal and proximal parts of the left upper arm. Additional neurological findings included oculomotor palsy and ataxia of the left arm. On the radiological studies, a mass lesion (germinoma) was found on the midbrain tegmentum, which was treated by conventional radiation therapy. Although there was improvement in the radiological imaging, his midbrain tremor became intolerable despite medical treatment. The authors performed MR guided stereotactic Vim thalamotomy. With radiofrequency lesioning in the right Vim, his resting, postural, and action tremors were much alleviated in both the distal and proximal parts of the left upper extremity. The authors consider that Vim thalamotomy is still an effective means of controlling midbrain tremors involving the proximal upper limb.

Adult↗
PubMed2001

Identification of Lck-derived peptides capable of inducing HLA-A2-restricted and tumor-specific CTLs in cancer patients with distant metastases.

The Lck protein (p56(lck)), a src family tyrosine kinase essential for T cell development and function, is aberrantly expressed in various types of cancers. We revealed recently that Lck can be a tumor antigen recognized by HLA-A24-restricted and tumor-specific cytotoxic T lymphocytes (CTLs) of cancer patients with metastases. In this study, we tried to identify Lck-derived epitopes capable of inducing HLA-A2-restricted and tumor-specific CTLs in cancer patients. The tumor-infiltrating lymphocytes (TILs) from 2 HLA-A2 cancer patients were found to respond to COS-7 cells when co-transfected with the lck gene and either HLA-A0201, -A0206, or A0207 cDNA. These TILs contained CTLs capable of recognizing either the Lck(61-69), the Lck(246-254), or the Lck(422-430) peptide among 24 different peptides, all of which were prepared based on the HLA-A2 binding motif. Importantly, in vitro sensitization with the latter 2 peptides induced tumor-specific CTLs in HLA-A2(+) cancer patients with metastases, but not in those without metastases. Overall, the Lck(246-254) and Lck(422-430) peptides could be useful for specific immunotherapy of HLA-A2(+) cancer patients, especially with distant metastases.

Animals↗
PubMed2001

Recognition of the Lck tyrosine kinase as a tumor antigen by cytotoxic T lymphocytes of cancer patients with distant metastases.

The Lck protein (p56(lck)), a src family tyrosine kinase that is essential for T cell development and function, is aberrantly expressed in metastatic colon cancers. p56(lck) seems to facilitate the malignant transformation of epithelial cells through initiation of anchorage-independent proliferation. We demonstrate that the lck gene encodes antigenic epitopes recognized by the HLA class I-restricted and tumor-specific CTL of metastatic cancer patients. Lck peptides augmented CTL activity in peripheral blood mononuclear cells (PBMC) of colon and other epithelial cancer patients with distant metastases, but not those without distant metastases. CTL precursors recognizing the Lck peptide were identified in freshly prepared PBMC of patients with distant metastases, and their frequency was significantly augmented by stimulation with the peptide. Thus, Lck peptides could be useful in developing a specific immunotherapy for cancer patients with distant metastases.

Antigens, Neoplasm↗
PubMed2001

Expression of serine proteinase inhibitor PP5/TFPI-2/MSPI decreases the invasive potential of human choriocarcinoma cells in vitro and in vivo.

OBJECTIVE: PP5/TFPI-2/MSPI is a Kunitz-type serine proteinase inhibitor with broad inhibitory spectra, abundantly produced by placenta and detected in the blood of pregnant women. Expression of PP5/TFPI-2/MSPI is exclusively detected in syncytiotrophoblasts of placenta, but is barely detectable in choriocarcinoma cells, a trophoblast-derived malignant tumor. Chromosome 7, in which the PP5/TFPI-2/MSPI gene is localized, is frequently lost in various types of tumors. We attempted to elucidate the relation between PP5/TFPI-2/MSPI expression and the malignant properties of choriocarcinoma cells. METHODS: Human choriocarcinoma cells, JAR, were transfected with either a human PP5/TFPI-2/MSPI expression vector or an empty vector, and stable clones were obtained. Messenger RNA expression, protein secretion/localization, growth rate, and plating efficiency were evaluated. In vitro migration and invasive activity were determined by transwell chamber experiments. In vivo tumor growth was evaluated by the subcutaneous injection of cells to nude mice and followed by histological examination. RESULTS: Expression of mRNA and protein of PP5/TFPI-2/MSPI were confirmed, and a high producing clone and a low producing clone were chosen for further analysis. The majority of secreted PP5/TFPI-2/MSPI protein was revealed to associate with the extracellular matrix. Expression of PP5/TFPI-2/MSPI did not affect the growth and migration of the tumor cells, but enhanced their plating efficiency. Its expression significantly inhibited invasion through the Matrigel. Invasive growth into the subcutaneous muscle layer was not evident in the nude mouse tumors of the PP5/TFPI-2/MSPI-expressing cells. CONCLUSION: PP5/TFPI-2/MSPI-expressing choriocarcinoma cells showed suppressed potential of invasion in vitro and in vivo. It is suggested that loss or suppression of PP5/TFPI-2/MSPI expression may result in the acquisition of invasiveness in choriocarcinoma cells.

Animals↗
PubMed2001

Cytocidal effect and DNA damage of nedaplatin: a mathematical model and analysis of experimental data.

PURPOSE: Cell cycle non-specific anticancer agents such as cis-diamminedichloroplatinum(II) are believed to depend linearly on the value of the area under the drug concentration time curve, which is supported by a mathematical model. However, the quantitative non-linear phenomena of both the cytocidal effect and DNA crosslink formation by cisdiammine(glycolato)platinum (nedaplatin) have been shown in vitro. Therefore, we developed a new mathematical model to explain these phenomena. METHODS: We assumed that nedaplatin enters intracellular fluid from medium through simple diffusion to form DNA crosslinks that kill cells. We developed a mathematical model to represent this assumption using differential equations that we then solved using an original computer program. The calculated results were compared with the experimental data. RESULTS: The drug's simple diffusion rate constant, the DNA crosslink formation rate constant, and the crosslink-dependent cell death rate constant in the model were 1.8 x 10(-14) (l h-1), 1.6 x 10(8) (l mol-1/2 h-1), 5.45 x 10(1) (mol-1), respectively. The model fits the experimental results statistically. The model also demonstrated theoretical proof that continuous exposure at a low dose was superior to the short exposure at a high dose seen in published experimental data. CONCLUSIONS: We developed a mathematical model to describe the non-linear pharmacodynamic effect of nedaplatin in vitro. This model may provide a novel drug infusion procedure for cancer patients.

Antineoplastic Agents↗
PubMed2001

Cytocidal effect and DNA damage of nedaplatin in vitro by simulating pharmacokinetic parameters.

PURPOSE: The pharmacodynamic effects of cis-diammine(glycolato)platinum (nedaplatin, 254-S) in vitro have been reported, but the dosage and exposure time in vitro have not always been based on clinical observations of the drug's actions in vivo. Regardless of the actual exposure conditions used, the effect of cell-cycle nonspecific anticancer agents such as nedaplatin is believed to depend on the area under the drug concentration-time curve (AUC). In this study, we evaluated the pharmacodynamics of nedaplatin in vitro, especially in relation to its AUC dependency, in terms of cell survival and DNA crosslinking. METHODS: BG-1 human ovarian cancer cells were treated with various concentrations of nedaplatin to simulate the pharmacokinetics of administration in a clinical setting. The BG-1 cells were exposed to nedaplatin dissolved in medium containing serum using constant concentration conditions, either high (maximum 7.69 mg/l) or low (average 1.33 mg/l). These concentrations were based on doses used in clinical studies. We then adjusted the exposure conditions in vitro to simulate the elimination of the drug from serum in vivo as follows: T1/2 alpha 1.20 h and T1/2 beta 2.70 h. The AUC values were set at 4, 8, 16, 25 and 40 mg.h/l for all exposure conditions. A colony-formation assay for the surviving fraction and an alkaline-elution assay for DNA crosslink measurement were done for the pharmacodynamic evaluation with comparison on the basis of the AUC value. RESULTS: Exposure to a low concentration for a long time was the most effective of the exposure conditions at the same AUC value. The greater the AUC value, the higher the crosslink index under all exposure conditions. This index tended to increase particularly after exposure to the low concentration. The natural logarithm of the surviving fraction (Y') was a linear function of the crosslink index regardless of the drug-exposure condition: ln(Y') = -87.2x + ln(5.79), R2 = 0.89. The threshold cytocidal effect was associated with a crosslink index of 0.02. CONCLUSION: There was a strong correlation between the cytocidal effect of nedaplatin and DNA crosslink formation. The cytocidal effect and DNA crosslinking in vitro depended on the exposure conditions used to define the AUC. Therefore, a new pharmacokinetic-pharmacodynamic model for nedaplatin must be constructed to investigate the most effective administration procedure in vivo.

Antineoplastic Agents↗
PubMed2001

Zymosan enhances the immune response to DNA vaccine for human immunodeficiency virus type-1 through the activation of complement system.

In the present study, the adjuvant effect of zymosan on human immunodeficiency virus type-1 (HIV-1)-specific DNA vaccine and the mechanism of this enhancement were studied in a murine model. We coinoculated zymosan with our candidate HIV-1 specific DNA vaccine (pCMV160IIIB) into skeletal muscles of BALB/c mice. Higher levels of both humoral immune response and HIV-specific delayed-type hypersensitivity (DTH) response were observed when zymosan was coinoculated with pCMV160IIIB compared with that obtained using pCMV160IIIB alone. HIV-specific cytotoxic T lymphocyte (CTL) activity was also enhanced. This enhancing activity was suppressed when coinoculated to the fifth complement (C5)-deficient DDD and AKR mice. The enhanced activity was also suppressed when anti-C3 antibody was inoculated to mice intramuscularly. There was significant induction of immunoglobulin G2a (IgG2a) and interferon-gamma (IFN-gamma) in pCMV160IIIB vaccine with zymosan. These results suggest that zymosan-mediated DNA vaccination enhances helper T cell (Th) 1-mediated immunity. The effect is suggested to be based on the consequences of its recruitment and activation of macrophages, dendritic cells or antigen-presenting cells (APC) through complement activation, especially through the alternative pathway. Taken together, these results suggest that zymosan can be an effective immunological adjuvant in DNA vaccination against HIV-1.

AIDS Vaccines↗