Transformation of NIH3T3 Cells with Synthetic c-Ha-ras Genes

Synthetic human c-Ha- ras genes in which amino acid codons were altered to those which are frequently used in highly expressed Escherichia coli genes were ligated to the 3'-end of Rous sarcoma virus long terminal repeat. When NIH3T3 cells were transfected with the plasmids having those genes with valine at codon 12, leucine at codon 61 or arginine at codon 61, transformants were efficiently produced. These results indicated that the synthetic c-Ha- ras genes are expressed in a mammalian system even though their codon usage is altered to correspond with that of E. colt. This expression vector system should he useful for studies on the structure-function relationships of c-Ha- ras , since the synthetic gene can be easily modified to have multiple base alterations, and can also be used simultaneously for the production of large amounts of p21 in E. coli for biochemical and biophysical studies.     

An intrathoracic vagus nerve schwannoma invading the trachea

A patient with a schwannoma of the intrathoracic vagus nerve is presented. The tumor invaded the trachea and caused dyspnea. It was successfully excised by a segmental resection of the trachea with end-to-end anastomosis. This instance of an intrathoracic vagus tumor invading the trachea is, as far as we know, the first reported in the world.     

A Simple, General Method for Detecting Retroviral RNAs Expressed in Cells

A simple, efficient method has been developed for detecting retroviral RNAs expressed in cells. In this method, total RNAs or poly A⁺ RNAs extracted from various human cells are separated by electrophoresis and hybridized with synthetic oligonucleotides corresponding to the 3'-terminal 18 nucleotides of various tRNAs. Genomic and subgenomic RNAs of HTLV-I and HTLV-II in virus-infected cells and of xenotropic murine leukemia virus expressed in human lung cancer cells were easily detected with the tRNA^Pro-derived oligonucleotide probe. This technique can be used to search for unidentified retroviruses expressed in human cancer cells and tissues.     

Estimation of dietary nutritional content using an online system with ability to assess the dieticians' accuracy

We developed an online system for estimating dietary nutritional content. It also had the function of assessing the accuracy of the participating dieticians and ranking their performance. People who wished to have their meal estimated (i.e. clients) submitted images of their meal taken by digital camera to the server via the Internet, and dieticians estimated the nutritional content (i.e. calorie and protein content). The system assessed the accuracy of the dieticians and if it was satisfactory, the results were sent to the client. Clients received details of the calorie and protein content of their meals within 24 h by email. A total of 93 dieticians (71 students and 22 licensed practitioners) used the system. A two-way analysis of variance showed that there was a significant variation (P=0.004) among dieticians in their ability to estimate both calorie and protein content. There was a significant difference in values of both calorie (P=0.02) and protein (P<0.001) estimation accuracy between student dieticians and licensed dieticians. The estimation accuracy of the licensed nutritionists was 85% (SD 10) for calorie content and 78% (SD 17) for protein content.     

Chemotherapy-resistant germ cell cancer of the testis treated by salvage surgery: a case report

A 38-year-old patient who had a non-seminomatous testicular cancer was treated by resection of the retroperitoneal metastatic mass that had proven refractory to bleomycin, etoposide and cisplatin (BEP) and paclitaxel, ifosfamide and cisplatin (TIP) chemotherapies. Although salvage chemotherapy was given against the chemorefractory metastatic lesions in the retroperitoneum, the serum alpha-fetoprotein level elevated to 3,252 ng/ml. Retroperitoneal lymph node dissection was performed, and viable cells were identified histopathologically in the resected tissues. The serum AFP level normalized after surgery. No recurrence has been observed for 22 months postoperatively. This experience indicates that salvage surgery even under high serum marker levels may have a beneficial outcome for selected cases of chemotherapy-resistant germ cell tumors.     

Diffusely Infiltrative Squamous Cell Carcinoma of the Esophagus

(Received for publication on Sept. 30, 1996; accepted on May 12, 1997)     

The association between renal tubular damage and rapid renal deterioration in the Japanese population: the Takahata study

Background

Injury to renal tubules plays an important role in the development of various renal diseases; however, the prevalence and significance of renal tubular damage in the general population are unclear. To clarify this point, we conducted a community-based study, using urinary ??₂-microglobulin as a marker of tubular damage.

Methods

The subjects studied were 3,444 Japanese over the age of 40?years. The urinary ??₂-microglobulin?Ccreatinine ratio (UBCR) was assessed in morning spot urine samples.

Results

In this population, the distribution of the UBCR among these subjects was skewed towards higher values and a high UBCR (??300???g/g) was identified in 438 (12.7%) subjects. However, overlap with macroalbuminuria and renal insufficiency [estimated glomerular filtration rate (eGFR) <60?mL/min/1.73?m²] was observed in only 25 (5.7%) and 58 (13.2%) of these subjects, respectively. Multivariate analysis indicated that a high UBCR was positively associated with aging, hypertension, macroalbuminuria and increased urinary sodium excretion. A 5-year longitudinal analysis in 899 subjects indicated a greater decline in eGFR in parallel with the increase in baseline UBCR. After adjustment for possible confounders, a high UBCR was an independent risk factor for rapid decline in eGFR [2; odds ratio 1.79 (95% confidence interval 1.07?C2.99), P?=?0.026].

Conclusion

This study showed that renal tubular damage was common and was an independent risk factor for renal deterioration in the Japanese population. More attention should be paid to occult renal tubular damage in order to prevent end-stage renal disease.     

Identification of tumor-initiating cells in a highly aggressive brain tumor using promoter activity of nucleostemin

Controversy remains over whether the cancer stem cell (CSC) theory applies to all tumors. To determine whether cells within a highly aggressive solid tumor are stochastically or hierarchically organized, we combined a reporter system where the nucleostemin (NS) promoter drives GFP expression (termed NS-GFP) with a mouse brain tumor model induced by retroviral Ras expression on a p16^Ink4a/p19^Arf-deficient background. The NS-GFP system allowed us to monitor the differentiation process of normal neural stem/precursor cells by analyzing GFP fluorescence intensity. In tumor-bearing mice, despite the very high frequency of tumorigenic cells, we successfully identified the NS-GFP⁺ cells as tumor-initiating cells (T-ICs). The clonal studies conclusively established that phenotypical heterogeneity can exist among the cells comprising a genetically homogeneous tumor, suggesting that this aggressive brain tumor follows the CSC model. Detailed analyses of the NS-GFP⁺ brain tumor cells revealed that T-ICs showed activation of the receptor tyrosine kinase c-Met, which functions in tumor invasiveness. Thus, the NS-GFP system provides a powerful tool to elucidate stem cell biology in normal and malignant tissues.