Trace element profiles in murine Lewis lung carcinoma by radioisotope-induced X-ray fluorescence.

Trace element profiles of various body tissues and tumor were established during growth of the Lewis lung tumor (LLT) with the use of radioisotope-induced X-ray fluorescence (RIXRF) analysis. The LLT, a highly malignant experimental murine tumor, resembles its human counterpart, has a well-defined life cycle, and kills its host in 30 days. When compared with normal controls, Zn, Br, and Rb levels in lung, liver, and skeletal muscle and Zn and Sr levels in bone from tumor-bearing mice exhibited large fluctuations at critical points in the tumor life cycle. In addition, the 24-day primary tumor trace element profile resembled that of its tissue of origin, normal lung, and was quite different from other normal tissues studied. These findings indicate that trace element profiles may help in the diagnosis, staging, and monitoring of disease. RIXRF is an excellent technique for this purpose because it is sensitive and relatively nondestructive of samples and has multielement capabilities.

Inhibition of experimental tumor growth in hamsters by small direct currents.

The effect of three electric current levels (3 mamp, 500 micronamp, and 960 mmicronamp) on the growth of A-Mel-4 tumor was evaluated in hamsters as a mode of therapy. Direct current (dc) was applied for one hour a day from the third to sixth posttumor implant day by the introduction of a shielded point electrode directly into the tumor site. Tumor growth was inhibited, and metastases were reduced in the exposed animals. The higher dl levels produced necrosis in the tumors, and in several animals, the implantation site tumor was completely destroyed. These effects were most pronounced with the positive electrode.

Evaluation of clinical chemistry laboratory performance in twenty Veterans Administration hospitals.

Twenty highly automated Veterans Administration (VA) Hospital laboratories participated in a study to evaluate their performances of routine chemistry tests. Ten of the laboratories had been identified as "superior" on the basis of previous College of American Pathologists Surveys. Several aspects of proficiency surveys were simultaneously examined: use of masked vs. unmasked survey specimens, methods of ranking, and comparison of medically useful performance criteria. The laboratories were found in general to be performing at the level of the state of the art and, more importantly, realistically meeting the criteria for medical needs for most routine tests. There was no difference between results obtained with masked and unmasked specimens. The ten "superior" laboratories showed slightly greater precision than the others, but were not more accurate, and two of them performed very poorly in the present study. The sum of squared SDI's was found to be a helpful technic for ranking and identifying outstanding and poor performances.

Pooled normal values, a useful technic.

Few laboratories determine their normal values, because of the work involved. This study attempted to see whether a group of laboratories, each contributing a portion of the samples, could pool their information to yield data applicable to the whole group. Each of 20 VA Hospital laboratories obtained approximately 20 fasting early morning specimens from healthy men, aged 20-29 years, during a four-week period. Routine chemistry examinations (16) were performed on Technicon AutoAnalyzers (12/60, 6/60, and AAII), and model S Coulter Counters were used for five hematology tests (381 values for each constituent). Within-day, day-to-day, and interlaboratory variance were determined in parallel-method variability studies. The data showed: (1) it is valid to pool normal values from different laboratories when non-random variables have been eliminated; (2) non-random variables can be identified by increased interlaboratory variance, whether differences such as methods and equipment are obvious or not; (3) normal values so derived agree well with those from large series performed in single laboratories.