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Objective: To establish reference intervals for serum free testosterone for DPC's Free Testosterone assay., Methods: We used data from healthy subjects and patients to determine reference intervals by parametric and non-parametric methods after partitioning by sex and age., Results: In males, there was a significant decrease in free testosterone concentrations with age. Reference intervals derived from a combination of 2075 "healthy" and patients' results gave similar values by parametric and nonparametric methods. However, the subgroups failed the test for Gaussian distribution. For each decade from 20 years on and > or = 60 years, the intervals based on 2.5th and 97.5th percentiles were: 24.1-94.8, 25.0-89.3, 23.4-81.7, 22.5-80.4, and 21.5-74.3 pmol/L respectively, in females, there was little change with age. The frequency distribution of 1915 patients was positively skewed, and showed a wider range than "healthy." Using square roots of values gave a Gaussian distribution. The central 95% intervals based on 187 "healthy" subjects were: 0.5-8.1 and 0.0-6.4 pmol/L for 20-59 and > or = 60 years, respectively., Conclusion: Developing reference intervals for free testosterone was complicated by the need to partition data by gender and age, difficulty in establishing disease in subjects and presence of physiological and other factors which can affect concentration in health and disease.

Objective: To evaluate the Ames Glucometer Elite glucose meter for use in point-of-care glucose testing in the neonatal intensive care unit., Methods: An important part of our quality control program involves a weekly comparison of glucose values obtained with each of the seven Elite analyzers and the Beckman CX7 analyzer located in the central laboratory. Each "split" sample involves measurement of the glucose by using the Elite analyzer in a sample of blood obtained from a heel stick at the bedside, followed by bleeding ("milking") 150 to 200 microl (4 to 5 drops) of blood into a heparinized microcontainer. This process should take no longer than 1 to 2 minutes, whereupon the microcontainer is placed on ice and sent to the laboratory. The values obtained were compared by regression analysis. Imprecision of the Elite meter was estimated at four levels of blood glucose concentration and on a normal-level quality control sample used for a period of 4 months., Results: Regression analysis between the glucose values obtained on the Elite meter and the CX7 meter revealed r = 0.93, p less than 0.0001, n = 188, Sy/x = 0.59 mmol/L, intercept = 0.47 +/- 0.14 mmol/L (1 SEM), and slope = 0.91 +/- 0.028 (1 SEM). When we switched to on-ice delivery of split samples to reduce metabolic activity during transport of the specimens to the laboratory, scatter about the regression line was decreased and the Sy/x was reduced to 0.45 mmol/L. Before the on-ice delivery of split samples, 24% of the Elite analyzer's results differed from those of the CX7 analyzer by more than 15%, whereas only 8% differed from those of the CX7 meter by more than 15% after on-ice delivery of split samples. Of 30 samples read as "Lo" by the Elite meter, 29 were less than 2.2 mmol/L on the CX7 meter, whereas only 1 was 2.2 mmol/L. The coefficients of variation taken as a measure of imprecision were less than 5% for the normal-level aqueous control and less than 5% for four heel-stick blood glucose levels., Conclusions: The Ames Glucometer Elite analyzer can be used with confidence in measuring heel-stick blood glucose concentrations at the bedside in the neonatal intensive care unit. Hypoglycemic blood samples are reliably detected. As with adults, meticulous technique should be followed to prevent filling defects, and all split samples should be analyzed promptly on the CX7 analyzer, with delivery to the laboratory on ice. Unlike previous generations of glucometers, the Elite meter has been well accepted by the neonatal nursing staff.

Attenuated or partial 21-hydroxylase deficiency is one of several biochemical defects in steroid metabolism that can lead to hirsutism in young women after puberty. The diagnosis is made through the exaggerated response of 17 alpha-hydroxyprogesterone (17-OH) to adrenocorticotrophic hormone (ACTH). To provide reference data 72 mild to moderately hirsute patients aged 18 to 35 were studied (over two years) with the ACTH test. Four patients with an exaggerated response were found. The mean (+/- 1SD) for zero time was 2.4 (0.96) nmol/l and for the 60 minute time was 7.2 (2.04) nmol/l. A subpopulation was found with a significantly higher baseline at 6.2 (1.3) nmol/l but a blunted 60 minute response at 8.7 (2.5) nmol/l. This is important because of the potential confusion arising from the known variability in baseline values in previously reported patients with partial 21-hydroxylase deficiency. Extending the test to 90 minutes did not show further increase in the 17-OH response to ACTH, thus confirming the validity of the 60 minutes ACTH test. The cortisol response to ACTH was also studied. One patient with presumptive partial 21-hydroxylase deficiency overlapped in cortisol response with eight of the reference population. Theoretically, a blunted cortisol response would be expected because of the postulated enzyme block, and these results suggest that other steroid enzyme defects should also be considered when an exaggerated 17-OH response to ACTH is seen.

The Beckman Synchron CX4 random-access multianalyzer was evaluated in a medium sized hospital laboratory. The instrument does end-point, rate, and multipoint assays and carries on-board reagents for 24 tests. In addition to predefined tests, the instrument can be programmed for 100 user-defined tests; these are stored on the hard disk and can utilize up to three component reagents each. The throughput is 200 tests per hour. There is stat testing capability. In our evaluation, within-run and between-run precision and linearity were good, and no reagent carryover was detected. There was good correlation with the in-house methodology for the 19 tests evaluated. A disadvantage at the time of evaluation was interference by elevated bilirubin on creatinine, phosphorus, uric acid, and triglycerides. This problem of interference is being addressed by the manufacturer.

Naloxone reverses hemorrhagic hypotension in the conscious guinea-pig. Captopril and saralasin impede this naloxone effect, suggesting that angiotensin II is involved in naloxone action. This is compatible with previous work which has shown that B-endorphin inhibits the centrally mediated pressor action of angiotensin II, and that naloxone blocks this effect. Naloxone may be interacting with the postulated brain renin-angiotension II system or may be blocking the action of shock-induced circulating angiotensin II on a centrally located area such as the hypothalamus.

Treatment of rats with the aminonucleoside of puromycin, which increases the incorporation of labelled phenylalanyl-tRNA into polypeptide chains in liver ribosome preparations studied in vitro, did not change the factor-dependent binding of fMet-tRNA f Met to ribosomes nor the peptidyl transferase function of the ribosomes. Peptidyl transferase function, as measured by fMet-tRNA f Met-puromycin formation, was comparable in the free and bound ribosome preparations. Similarly, the factor-dependent binding of fMet-tRNA f Met to ribosomes was the same in free ribosome preparations obtained from rat liver as it was in bound ribosome preparations that had been freed of membranes by puromycin incubation and high salt wash.