Selection and counting of aerobic gram-negative bacilli in saliva by the spiral system.

A four-month pilot study involving 100 volunteers, 100 hospitalised patients not on antibiotics and 100 patients on antibiotics was performed using a non labor-intensive system involving inoculator, laser colony counter and 14-cm petri dishes containing MacConkey medium to determine the number of aerobic gram-negative bacilli present in saliva. All colonies greater than or equal to 0.75 mm in diameter were found to be aerobic gram-negative bacteria.

Comparison of a simplified radioimmunoassay with a gas-liquid chromatographic method for urinary aldosterone.

A simplified radioimmunoassay for the measurement of aldosterone in urine, requiring only an extraction without any further purification is described. The results obtained on 47 urine specimens were compared with those obtained by a gas-liquid chromatographic method. An excellent correlation was found (r = 0.