Characterization of a novel human natural killer-cell line (NK-YS) established from natural killer cell lymphoma/leukemia associated with Epstein-Barr virus infection

A novel cell line was established from a patient with a leukemic-state nasal angiocentric natural killer (NK) cell lymphoma with systemic skin infiltration. The morphology of the leukemic cells was large-granular-lymphocyte (LGL), and their immunophenotype was CD2+, CD3-, CD5+, CD7+, CD16-, CD56+, and CD57-. The presence of Epstein-Barr viral (EBV) genome was shown in specimens from the patient's nose, skin, and peripheral blood by in situ hybridization using an EBV-encoded small RNA-1 probe or by Southern blotting using a terminal-repeat probe of the EBV genome. Leukemic cells were cocultured with a mouse stromal cell line (SPY3-2) in the presence of 100 U/mL recombinant human interleukin-2 and a novel stromal cell-independent cell line, NK-YS, was established. The NK-YS cells showed LGL morphology and expressed surface CD2, CD5, CD7, CD25, CD56, and CD95. The NK-YS cells retained cytotoxicity against K562 and Jurkat cells. A Southern blotting using a terminal-repeat probe of EBV showed that NK-YS and fresh leukemic cells had a clonal EBV genome, whereas the T-cell receptor beta and gamma chain genes of NK-YS were not rearranged. In an immunocytochemical analysis, the NK-YS cells showed a type-II latent infection of EBV. The NK-YS cells preserved the original characteristics of NK cell lymphoma/leukemia and will be a useful tool for the study of biological characteristics of EBV-associated nasal angiocentric NK cell lymphoma/leukemia.     

Polarization-independent electroabsorption modulators using strain-compensated InGaAs-InAlAs MQW structures

The improved modulation properties of strain compensated InGaAs-InAlAs multiple quantum well (MQW) electroabsorption modulators and their modules have been demonstrated. Introduction of a 0.5% tensile strain in wells and a 0.5% compression in barriers provides highly efficient operation such as a low driving voltage (V/sub 20/ dB=1.6 V) and a large modulation bandwidth (f/sub 3/ dB>20 GHz). This is in addition to low polarization-dependence with an extinction ratio difference between TE and TM and polarization of less than 1 dB.     

Management for stage II glottic carcinoma: radiation therapy or surgery

AIM: To analyze the results of stage II glottic carcinoma treated with radiotherapy or surgery. PATIENTS AND METHOD: One hundred thirty-four patients with squamous cell carcinoma of the T2N0M0 glottic carcinoma treated at the Osaka Medical Center for Cancer and Cardiovascular Diseases from 1979 through 1991 were reviewed. The 5-year disease-free survival and laryngeal preservation rate and prognostic factors were examined. Treatment was radiation therapy with salvage surgery for failure or surgery alone. RESULTS: The 5-year disease-specific survival rate for the radiotherapy group was 100% and for the surgery group, 93% (p = 0.055). In the surgery group 5-year disease-specific survival rate for the subgroup of cord mobility was 94% and that of impaired cord mobility, 89% (p = 0.5354). Concerning laryngeal preservation the radiotherapy group showed better preservation rate than the surgery group in the subgroup of cord mobility, i.e., 41/51 (80%) versus 6/55 (11%) (p < 0.001) although significant difference was not observed in the lesion with impaired cord mobility, 2/5 versus 4/22 (p = 0.171). CONCLUSION: We recommend radiation therapy for stage II glottic carcinoma with normal cord mobility, although further study is needed to improve the preservation rate of the larynx with keeping the disease-specific survival for the lesion with impaired cord mobility.     

PWM Inverter Using High-Gain Pulse-Triggered Power Transistors and a New PWM Control Method

Rugged PWM transistor inverters are expected to be put into practical use for providing high reliability under adverse operating conditions. The bipolar power transistors are more common compared with MOSFET's power transistors in balance between power-handling capability and switching speed. High over current capability, low switching loss, high-speed switching, and high-current gain are requisite functions in the PWM inverter employing bipolar power transistors. These functions are of great concern in the power electronics field. A new PWM transistor inverter which can meet these requirements is presented in this paper. For this purpose, a concept of high-gain pulse-triggered power transistor (PTPT) with amorphous saturable current transformer (CT) is introduced.     

VLDL triglyceride kinetics in Wistar fatty rats, an animal model of NIDDM: effects of dietary fructose alone or in combination with pioglitazone

The effects of dietary fructose alone or in combination with a new oral agent, pioglitazone, on VLDL-triglyceride (TG) turnover were studied in genetically obese Wistar fatty rats characterized by hyperinsulinemia (7,488 +/- 954 pmol/l), hyperglycemia, (22.5 +/- 1.4 mmol/l), and hypertriglyceridemia (4.39 +/- 0.54 mmol/l). They had an increased hepatic TG production (16.2 +/- 0.1 micromol/min; lean rats, 5.4 +/- 0.3 micromol/min) as well as a longer half-life of VLDL-TG from lean donors (8.8 +/- 1.4 min, lean recipients; 2.3 +/- 0.9 min). In addition, in lean recipients, the half-life of VLDL-TG from fatty donors was longer than that from lean donors (4.80 +/- 0.56 vs. 3.14 +/- 0.23 min). Although feeding fructose into fatty rats did not change plasma glucose and insulin levels, it produced a twofold increase in TG levels (8.74 +/- 1.15 mmol/l). This was associated with a 1.7-fold increase in TG production to 27.5 +/- 1.2 micromol/min, while no significant change was found in the half-life of lean VLDL-TG in fructose-fed fatty recipients (10.9 +/- 2.4 min) or in that of VLDL-TG from fructose-fed fatty donors in lean recipients (4.46 +/- 0.76 min). Daily administration of pioglitazone (3 mg/kg body weight) in fructose-fed fatty rats ameliorated glycemia and triglyceridemia to the level of lean rats (8.1 +/- 0.7 and 1.18 +/- 0.05 mmol/l, respectively) and insulinemia to a lesser extent (2,712 +/- 78 pmol/l). A fall in TG levels was associated with improvement of an impairment in the ability of fructose-fed fatty rats to remove lean VLDL-TG (half-fife: 2.6 +/- 0.6 min). Pioglitazone, however, produced no change in TG production (25.9 +/- 2.7 micromol/min), the half-life of VLDL-TG from fructose-fed fatty donors in lean recipients (4.17 +/- 0.38 min), or the activity of lipoprotein lipase and hepatic lipase in postheparin plasma. We conclude that in Wistar fatty rats 1) hypertriglyceridemia is attributed to TG overproduction and impaired TG catabolism, and the latter is due to changes in both VLDL, such that they are less able to be removed, and changes in the nature of Wistar fatty rats, such that they are less able to remove VLDL-TG; 2) fructose further increases hepatic TG production with a resultant deterioration in hypertriglyceridemia; 3) pioglitazone normalizes TG levels by altering the physiology of the Wistar fatty rats in a manner that increases their ability to remove VLDL-TG from the circulation.     

Percutaneous transhepatic biliary drainage for the treatment of obstructive jaundice caused by metastases from nonbiliary and nonpancreatic cancers

The usefulness of percutaneous transhepatic biliary drainage (PTBD) in the treatment of obstructive jaundice caused by metastases from nonbiliary and nonpancreatic cancers was evaluated. Eighteen patients underwent PTBD during a 3-year period. The primary cancers were located in the stomach (nine cases), colon (four), lung (three), uterus (one), and breast (one). The causes of obstructive jaundice and bile duct strictures were investigated using both abdominal computed tomography and abdominal ultrasonography. The causes of obstructive jaundice, the usefulness of PTBD in terms of the relief of symptoms and laboratory data, survival after PTBD, and the relationship between patient characteristics and survival were evaluated. Obstructive jaundice was most often attributable to metastases to the lymph nodes (17 of 18 cases). One case was attributed to metastasis to the liver. PTBD decreased the jaundice and relieved the symptoms caused by biliary tract obstruction. Median survival after PTBD was 59 days. Patients whose performance status was 2 or less survived longer than those with a performance status of 3 or more (P=0.018). Furthermore, patients aged less than 60 years tended to survive longer than those aged 60 or over (P=0.057). Our results suggest that PTBD is useful for relief of symptoms caused by obstructive jaundice in patients with nonbiliary and nonpancreatic cancers.     

Catechol-O-methyltransferase genotype and susceptibility to Parkinson's disease in Japan. Short communication

We report -108Met/Val polymorphism of the COMT gene in Japanese patients with Parkinson's disease (PD). The allele frequency for -108Val was higher in PD patients compared with controls, although the differences did not reach the statistical significance. However, the frequency of -108Val homozygotes was significantly higher in PD patients (56.8%) than in control subjects (44.2%), and heterozygotes of -108Met/Val were less in PD. COMT gene polymorphism may constitute a genetic risk factor for PD among Japanese.     

Accuracy of treadmill exercise electrocardiography in detecting restenosis following single-vessel percutaneous transluminal coronary angioplasty

To develop an improved method for diagnosing restenosis using treadmill exercise electrocardiography (ECG) following percutaneous transluminal coronary angioplasty (PTCA), we prospectively evaluated 46 patients who underwent PTCA for the treatment of single-vessel coronary artery disease and who did not have a history of myocardial infarction. Treadmill exercise ECG and coronary angiography were performed 3 months after PTCA to determine their accuracy in diagnosing restenosis based on standard ST-segment depression criteria, the difference between the maximum ST-segment depression before and 3 months after PTCA (< or =0.5 mm: positive; >0.5 mm: negative), and the difference between sigmaST-segment depression before PTCA and 3 months after PTCA (< or = 1.5 mm: positive; > 1.5 mm: negative). The sensitivity, specificity, and diagnostic accuracy of standard ST-segment depression criteria were 65%, 66%, and 65%, respectively. The sensitivity, specificity, and accuracy for the difference in maximum ST-segment depression were 77%, 76%, and 76%, respectively, whereas the values for the difference in sigmaST-segment depression were 77%, 83%, and 80%, respectively. Based on these results, we conclude that using the difference between ST-segment depression before and after PTCA improves the accuracy of treadmill exercise ECG for diagnosing restenosis.