Biomedical subjects

H Shiomi

Publications and source records attributed to H Shiomi.

79 records · Page 5Linked to original sources

PubMedDate not supplied

Characteristics of calcium ion influx induced by human follicular fluid in individual human sperm.

The mechanism of Ca2+ influx into human spermatozoa was investigated. Human follicular fluid (hFF), which contains progesterone, stimulated an increase in the concentration of intracellular free Ca2+ ([Ca2+]i) as measured by fluorescence spectroscopy using Fura-2/AM. The technique allowed the measurement of [Ca2+]i in individual, motile spermatozoa, by improvement of the previous methods. The role of Ca2+ channels was investigated using selective blocking agents. Neither blockade of L-type channels with verapamil or lanthanum (La3+) nor blockade of N-type channels with omega-conotoxin affected the hFF-stimulated increase in [Ca2+]i. Blockade of T-type channels with either nickel (Ni2+) or amiloride significantly reduced the hFF-stimulated increase in [Ca2+]i and amiloride significantly decreased baseline [Ca2+]i. Incubation of sperm in Na(+)-free medium did not affect [Ca2+]i, indicating that Na+/Ca2+ exchange has no major role in Ca2+ influx. The results suggest that calcium influx induced by hFF occurs via T-type voltage-independent Ca2+ channels. The method described allows accurate measurement of [Ca2+]i in individual, motile human spermatozoa.

Amiloride↗

PubMedDate not supplied

Ultrasonographic monitoring of high dose rate interstitial implant using template technique for oral tongue cancer.

192Ir high dose rate (HDR) fractionated interstitial brachytherapy was performed on two patients with tongue cancer with the aid of real-time intraoral ultrasonographic (US) guidance and the template technique. Blind-ended catheters with metallic rods (Obturator, Nucletron, the Netherlands) were inserted into the tongue from the submandibular region. This US monitoring allows for detection of the accurate location of both tumor and catheters in real-time motion. After implantation, we reconfirmed the position of the catheters by CT examination. Intraoral US monitoring was thus found to be a useful procedure for accurate implantation of brachytherapy for tongue cancer.

Brachytherapy↗

PubMedDate not supplied

Quality assurance for an image-guided frameless radiosurgery system using radiochromic film.

PURPOSE: The CyberKnife, a new type of machine for stereotactic irradiation, is composed of a combination of a robot (manipulator) and a linear accelerator; We measured the total pointing error of the therapy beam, aiming at improvement in the accuracy of the CyberKnife. METHODS AND MATERIALS: The CyberKnife keeps a number of coordinate systems such as the patient's coordinates, robotic coordinates, and IPS (image processing system) coordinates. Precise irradiation is possible if these coordinate systems are matched accurately. We always calculate the overall irradiation error using GAF MD-55 radiochromic film before irradiation treatment of the patient, and we have attempted to improve the accuracy of irradiation with the CyberKnife by feeding back the errors. RESULTS: The median of the error immediately after introducing the CyberKnife was 1.2 mm, and as a result of correction, we succeeded in reducing the error to 0.7 mm (median). Total pointing error after correction was significantly lower than that before correction (p=0.0023). CONCLUSIONS: This approach allowed us to reduce errors and establish a method for providing patients with highly accurate stereotactic irradiation. We believe these results endorse the validity of the method presented in this paper.

Film Dosimetry↗

PubMedDate not supplied

Comparison of the long-term results of brachytherapy for T1-2N0 oral tongue cancer treated with Ir-192 and Ra-226.

BACKGROUND: The authors report the compatibility of iridium-192 (Ir-192) to Radium-226 (Ra-226) based on the clinical results of three-decades. METHODS: From 1967 through 1985, 119 patients with early oral tongue cancer (T1-2N0) were treated with conventional Ra-226 needles and 135 patients with Ir-192 hair pins. RESULTS: Local control rates at 10 years for T1 and T2 tongue cancer were 79% and 61% for patients treated with Ra-226, 83% and 68% with Ir-192. The 10-year cause-specific survival rates for the T1 and T2 patients with Ra-226 were 76% and 63%, and those with Ir-192 were 77% and 68%, respectively. CONCLUSIONS: Ir-192 showed good possibilities as a substitute for Ra-226 in brachytherapy for early oral tongue cancer.

Adult↗

PubMedDate not supplied

Age as a prognostic factor for late local recurrence of early tongue cancer treated with brachytherapy.

BACKGROUND: We aimed to examine predisposing factors on late local recurrence of early oral tongue cancer (T1-2N0). METHODS: We analysed 152 patients with no evidence of disease 2 years after interstitial radiation therapy without external radiation. RESULTS: Multivariate analysis showed age to be the only significant prognostic factor for late local control (p = 0.03). We then examined the influence of age by comparing the results between 36 older patients (age more than, or equal to, 65) and 116 other control patients (age less than 65). Aged patients showed poor local control rates of 62% at 10 years after treatment, whereas the corresponding figures for control patients were 90% (p = 0.003). The cause specific survival rate at 10 years was also lower in elderly patients (75%) than in control patients (93%, p = 0.02). CONCLUSIONS: Age is a predisposing factor for late local recurrence in patients free from disease 2 years after treatment.

Adult↗

PubMedDate not supplied

Tongue cancer treated with brachytherapy: is thickness of tongue cancer a prognostic factor for regional control?

BACKGROUND: We aimed to investigate the predisposing factor for lymph node metastasis and examine the influence of thickness for lymph node recurrence in oral tongue cancer. METHODS: We analysed 254 patients with early oral tongue cancer (T1-2N0) who were treated with brachytherapy from 1967 through 1985. RESULTS: T category (p = 0.005), and thickness (p = 0.04) were identified as a significant predisposing factors for neck failure. 50%, 40% and 30% were the incidences of lymph node metastasis for patients with thickness of tumor more than 11 mm, 6-10 mm and 5 mm or less. Furthermore, T category (largest diameter of lesion) correlates strongly to thickness of tumor. CONCLUSIONS: Although it is not an independent factor, thickness is a significant predisposing factor for lymph node metastasis.

Adult↗

PubMedDate not supplied

5 Gy irradiation does not alter the expression level of WT1 (Wilms tumor gene) in K562 and ML1.

Recently, Wilm's Tumor gene (WT1) has been identified as a predisposing indicator for the activity of leukemia. To know the influence of irradiation on the expression level of WT1, we examined changes in WT1 expression after 5 Gy of irradiation of the K562 and ML1 cell lines (lymphoblastic cell lines). 48 hours after irradiation we could not find any alteration in the expression of WT1 at the mRNA and protein levels. Therefore, our results indicate that 5 Gy of irradiation does not induce differentiation of the leukemia cells.

DNA-Binding Proteins↗