HSV-NIS, an oncolytic herpes simplex virus type 1 encoding human sodium iodide symporter for preclinical prostate cancer radiovirotherapy

Several clinical trials have shown that oncolytic herpes simplex virus type 1 (oHSV-1) can be safely administered to patients. However, virus replication in tumor tissue has generally not been monitored in these oHSV clinical trials, and the data suggest that its oncolytic potency needs to be improved. To facilitate noninvasive monitoring of the in vivo spread of an oHSV and to increase its antitumor efficacy, the gene coding for human sodium iodide symporter (NIS) was incorporated into a recombinant oHSV genome and the corresponding virus (oHSV-NIS) rescued in our laboratory. Our data demonstrate that a human prostate cancer cell line, LNCap, efficiently concentrates radioactive iodine after the cells have been infected in vitro or in vivo. In vivo replication of oHSV-NIS in tumors was noninvasively monitored by computed tomography/single-photon emission computed tomography imaging of the biodistribution of pertechnetate and was confirmed. LNCap xenografts in nude mice were eradicated by intratumoral administration of oHSV-NIS. Systemic administration of oHSV-NIS prolonged the survival of tumor-bearing mice, and the therapeutic effect was further enhanced by administration of ¹³¹I after the intratumoral spread of the virus had peaked. oHSV-NIS has the potential to substantially enhance the outcomes of standard therapy for patients with prostate cancer.

Expression of prothymosin-alpha and c-myc mRNA in human gastric cancer

Prothymosin-alpha (PT-alpha) is a nuclear protein involved in cell proliferation. c-myc is implicated in the carcinogenesis of many human cancers. PT-alpha gene transcription is reported to be regulated by the c-myc gene in vitro. However, little has been reported on the PT-alpha and c-myc mRNA expressions in gastric cancer. We semi-quantitatively determined the PT-alpha and c-myc mRNA expressions in 60 pairs of gastric cancer tissue (T) and corresponding normal tissue (N) using the reverse transcriptase-polymerase chain reaction method. The average of T/N ratio was 1.20 for PT-alpha and 1.30 for c-myc. Cases demonstrating a T/N ratio of more than 1.0 were seen in 33 (55%) and 30 (50%) cases for PT-alpha and c-myc, respectively. No significant correlation was observed between either of these two mRNA expressions and any of the examined clinicopathologic factors for gastric cancer. However, a significant correlation was seen between the expressions of both genes (p<0.0001). The findings support the hypothesis that, regarding human gastric cancer, the transcription of PT-alpha is considered to be under the control of c-myc gene, however, the value of these gene expressions do not reflect biological behavior.

Correlation between reduced p21(WAF1/CIP1) expression and abnormal p53 expression in esophageal carcinomas

p21(WAF1/CIP1) is a potent inhibitor of various cyclin-dependent kinases, the expression of which is transcriptionally regulated by tumor suppressor gene product p53. We immunohistochemically examined the expression of p53 and p21(WAF1/CIP1) in 61 esophageal squamous cell carcinomas. p53 protein was expressed in 37 (61%) of 61 carcinomas. p21(WAF1/CIP1) was consistently expressed in the normal stratified esophageal mucosa. In the carcinomas, the expression of p21(WAF1/CIP1) protein was markedly reduced or not expressed in 33 (54%) cases. Clinicopathologic analyses revealed that no significant correlation exists either between p53-positive and -negative cases or between p21(WAF1)/(CIP1)-positive and -negative cases. Twenty-four cases were p53-positive/p21(WAF1/CIP1) negative, 15 were p53-negative/p21(WAF1/CIP1)-positive, 13 were positive for both and 9 were negative for both, and these findings thus showed an inverse correlation of the positivity between p53 and p21(WAF1/CIP1) (p<0.05). Furthermore, of the 13 cases with positive staining for both, the distribution of the expression was mutually exclusive in 6 cases and coincidental in the remaining 7 cases. These findings showed the p53-dependent expression of p21(WAF1/CIP1) was observed in esophageal squamous cell carcinomas, while the lack of an absolute correlation between abnormal p53 expression and p21(WAF1/CIP1) expression suggested that the p53-independent expression of p21(WAF1/CIP1) might also occur in some portions of the esophageal squamous carcinomas, suggesting that the molecular mechanisms of esophageal carcinogenesis appear to be complicated.

Microsatellite instability in Japanese colorectal carcinoma

Recent studies have shown that microsatellite instability (MSI) play an important role in the development of various types of cancer. To clarify the clinicopathologic significance of MSI in colorectal carcinoma (CRC), the presence of MSI was examined in 54 Japanese cases of CRC using the polymerase chain reaction-based method. The incidence of MSI in CRC cases was 13 out of 54 cases (24%). CRC with MSI also showed a significant tendency not to have lymph node metastasis (P<0.05), although neither the survival nor the prognosis of the cases examined in this study were available due to the short period of follow-up. The present study showed that the incidence of MSI in Japanese CRC was 24% and suggests that CRC with MSI may behave in a less malignant manner.

Metastable Defects of Iron-Boron Pair in Silicon

We have found configuratlonally metastable Fe-B pairs in Si by using dark or photo capacitance-transient technique combined with minority-carrier injection. The metastable pairs are observed as four electron-trapping levels at Ec-0.43 eV, 0.46 eV, 0.52 eV, and 0.54 eV and as two hole-trapping levels at Ev+0.53 eV and 0.48 eV after the injection at 150 K. The production of each level is investigated under various injection conditions, and the annihilation process is studied by isochronal anneals.

Measurement of xenon plasma properties in an ion thruster using laser Thomson scattering technique

This paper reports on the development of a method for measuring xenon plasma properties using the laser Thomson scattering technique, for application to ion engine system design. The thresholds of photo-ionization of xenon plasma were investigated and the number density of metastable atoms, which are photo-ionized by a probe laser, was measured using laser absorption spectroscopy, for several conditions. The measured threshold energy of the probe laser using a plano-convex lens with a focal length of 200 mm was 150 mJ for a xenon mass flow rate of 20 μg/s and incident microwave power of 6 W; the probe laser energy was therefore set as 80 mJ. Electron number density was found to be (6.2 ± 0.4) × 10(17) m(-3) and electron temperature was found to be 2.2 ± 0.4 eV at a xenon mass flow rate of 20 μg/s and incident microwave power of 6 W. The threshold of the probe laser intensity against photo-ionization in a miniature xenon ion thruster is almost constant for various mass flow rates, since the ratio of population of the metastable atoms to the electron number density is little changed.