The complement-dependent bacteriolytic activity of normal human serum. I. The effect of pH and ionic strength and the role of lysozyme

The bacteriolytic activity of normal human serum on a rough strain of E. coli has been studied by a turbidimetric method. Bacteriolysis was found to be markedly dependent on ionic strength and pH, with optima at micro = 0.06 and pH 8.3-8.5, respectively. The method of cultivating the cells also influenced the rapidity of lysis. Lysis was temperature-dependent and was exhibited by all samples of human serum tested. Microscopically, organisms incubated with serum were observed to swell, loose their rod shape and eventually burst, leaving remnants of the cell membrane in suspension. Sphaeroplasts were obtained by brief exposure of cells to serum followed by dilution into 5 per cent sucrose. The bacteriolytic reaction was shown to require complement. No definite requirement for properdin or specific antibody in this system could be demonstrated by the absorption of serum with zymosan and with homologous cells respectively. The latter procedure was found to reduce bacteriolytic activity by removal of serum lysozyme. Absorption of serum with bentonite also led to loss of bacteriolytic activity which could be restored with lysozyme. The organism was not lysed by lysozyme alone, but lysis occurred with lysozyme + EDTA in tris buffer. The possibility of complement acting independently of antibody or properdin, in certain instances, is discussed in relation to bacterial cell wall structure. Data are presented supporting the hypothesis that the "substrate" of complement in cell membranes is a lipid or lipoprotein.

Continuous recording of arterial pO2, pCO2, pH, and O2 saturation in vivo

Methods are described for concurrent, continuous, and automatic recording of paO2, paCO2, apH, and SaO2 of the arterial or venous blood. Measurements were obtained by catheterization of vessels as small as 1 mm in diameter. Graphs of these parameters may be compared with similar measurements in tissue, such as the brain, and correlated with records of function (EKG, EEG, pneumograph). Continuously flowing blood was brought into contact with electrodes and a cuvette for measuring pCO2, pO2, pH, and arterial oxygen saturation by means of catheters and an electrode housing and was then returned to the circulation. For arterial measurements, an arteriovenous shunt was used, for venous blood a mechanical pump is necessary. pCO2 was determined by a membrane-covered pH electrode, pO2 by a membrane-covered polarograph electrode, pH by a small glass electrode, SaO2 by a flow-through oximeter cuvette. Alterations in arterial pH influence SaO2 and paO2 in opposite directions (Bohr effect). Brain tissue parameters reflect changes in arterial pO2, pCO2, and pH but often move independently due to localized changes in tissue circulation and metabolism.

Submitted on October 10, 1960

Simultaneous determinations of blood pressure and blood pH in cases of suspected pheochromocytoma

Eight hundred fifty-seven determinations of the pH of venous blood with simultaneous blood pressure observations were carried out on 590 patients. The pH of venous blood of the patients who had been under medication for a long period before the tests did not vary significantly from that of patients who had had no medication. The most consistent result was the rise in the pH of venous blood 30 minutes after a dose of phentolamine hydrochloride (Regitine). The oral administration of 40 grains of sodium bicarbonate did not increase the response of the blood pressure during the histamine test, irrespective of the type of previous medication, even though the pH of the venous blood was low initially and rose to normal levels after the administration of the sodium bicarbonate. This may be due to the fact that none of the patients had pheochromocytomas with excessive release of pressor amines.