Evaluation of an adenosine 5'-triphosphate assay as a screening method to detect significant bacteriuria

The bioluminescent reaction of adenosine 5'-triphosphate (ATP) with luciferin and luciferase has been used in conjunction with a sensitive photometer (Lab-Line's ATP photometer) to detect significant bacteriuria in urine. This rapid method of screening urine specimens for bacteriuria was evaluated by using 348 urine specimens submitted to the clinical microbiology laboratory at the University of Minnesota Hospitals for routine culture using the calibrated loop-streak plate method. There was 89.4% agreement between the culture method and the ATP assay, with 7.0% false positive and 27.0% false negative results from the ATP assay using 10(5) organisms/ml of urine or greater as positive for significant bacteriuria and less than 10(5) organisms/ml as negative for significant bacteriuria.     

Healing of deep venous thrombosis: venographic findings in a randomized study comparing streptokinase and heparin

Sequential ascending venographic studies were used to assess the healing of deep venous thrombosis in 50 patients randomly assigned to streptokinase or heparin therapy. Various degrees of thrombolysis and/or recanalization were demonstrated by venograms performed on the fourth and tenth days of treatment. Late follow-up studies (mean, 7 months after treatment) showed three basic patterns of resolution: (1) return to normal, (2) complete recanalization, and (3) incomplete recanalization and/or collateralization. Loss of valves or their function was associated with recanalization. The character, speed, and outcome of healing reflected the nature and extent of thrombosis, prior thrombotic disease in the extremity, and the type and timing of treatment. Streptokinase was highly effective and preferable to heparin in patients with deep vein thrombosis when therapy was begun within 4 days of onset of symptoms. In later stages of acute or recurrent deep vein thrombosis, the effectiveness of both drugs was significantly reduced.     

Regulation of nitrogen catabolic enzymes in chick liver -- effects of amino acids

It is well-known that in the chick, dietary protein increases the levels of several hepatic enzymes that are involved in nitrogen metabolism and excretion. However, the biochemical mechanism of this response is essentially unknown. The experiments presented in this paper show that the chick is responding to alpha-amino nitrogen and not to any specific amino acid. Furthermore, it is shown that this system responds to endogenous sources of nitrogen as well as dietary protein and that the xanthine dehydrogenase response involves regulation of enzyme synthesis without changing the rate of degradation.     

Calculation of the volume of the grafted kidney. Value of this measurement by echotomography in renal transplantation

From a necropsy series of 14 kidneys, it is very easy to prove, that there is a quite good correlation between the theorical calculated volume of the kidney and its real volume. It is possible to compare the kidney to an ovoid, and to calculate its volume, knowing the 3 dimensions which are its length, its width, its depth. In this way, by echotomography it is possible to estimate these three parameters at the level of the transplanted and to calculate the volume and if, after two successive examinations of control, the kidney volume is found to be enlarged (over 20%) a reject phenomenon must be diagnozed.     

Differing effects of the vasodilator drugs, prazosin and diazoxide on plasma renin activity in the dog

1. The effects of intravenous (i.v.) administration of the vasodilator drugs prazosin or diazoxide on blood pressure and plasma renin activity were evaluated in the anaesthetized dog. 2. Prazosin and diazoxide both induced a rapid reduction in the mean arterial pressure to 73% and 75% of control values respectively. 3. Prazosin lowered plasma renin activity to 62% (P less than 0-025) of the control value whereas diazoxide raised plasma renin activity to 178% (P less than 0.05) of the control value. 4. The combination of vasodilatation and low renin activity observed following the administration of prazosin is unique, and may have clinical significance if these factors reduce the vascular complications of hypertension.     

Digital low-pass filtering

Random noise beyond the maximum signal frequency of the imaging system can be removed by low-pass filtering without compromising signal transmission.     

Control of cell growth. II. Requirement of thyroid hormones for the in vivo estrogen-dependent growth of rat pituitary tumor cells

A subclone of rat pituitary tumor cells, designated GH3/C14, was isolated from the parent population of GH3 pituitary cells and was estrogen-dependent for growth in vivo. GH3/C14 cells inoculated into host animals formed tumors in intact females, estrogen-treated ovariectomized females, and estrogen-treated males, but not in untreated intact or castrated males, or untreated ovariectomized females. Exogenous treatment with estrogens supported tumor formation in male animals. Radioimmunoassay of the average serum estradiol concentrations that support tumor growth in intact females, estradiol-treated intact females, and estradiol-treated intact males gave values of 41 +/- 4, 1,130 +/- 150, and 730 +/- 140 pg/ml, respectively. Tumor formation by GH3/C14 cells inoculated into male animals was not supported by either exogenous progesterone or hydrocortisone acetate. Further, these two steroid hormones had no significant effect on the estrogen-promoted growth in males or females. Exogenous testosterone treatment promoted tumor formation in males and ovariectomized females, but dihydrotestosterone was completely ineffective. Radioimmunoassay of the serum from tumor-bearing animals and the medium from the cells in culture showed that the cells produced growth hormone in vivo and in vitro but did not produce measurable amounts of luteinizing hormone or follicle-stimulating hormone. The groth of GH3/C14 cells in culture was examined in medium without added estrogen, and with estradiol added to the level of either the normal intact female rat or the estradiol-treated animals. No direct growth stimulation by estrogens could be detected in culture; the data suggested an indirect growth control mechanism.