Autorhythmometry in hypertension: some methodological aspects and clinical implications

Autorhythmometry of blood pressure is a technique easy to be performed and well accepted by hypertensive patients. A simple inspection of data self-collected 5 times a day for many days constitute a sufficiently reliable automonitoring of blood pressure both in basal conditions and in relation to the efficacy of some dietary and/or pharmacological treatment. Several examples are reported to show that more sophisticated statistical manipulation of the data collected may give rise to a better understanding of some clinical and physiological aspects. Both analysis of variance, performed on individual subsets of data averaged at each sampling hour, and single cosinor, performed on longitudinal time series, may be used to detect and quantify a circadian rhythm as a systematic daily variation, averaging towards zero the noise superimposed to the actual time series. Serial section analysis of the data, along all the experimental span, is useful to detect a) the reproducibility of the rhythm b) the variation of its parameters induced by changes in the experimental conditions c) the long-term trend. In the first subject the influence on the circadian rhythm of the pulse rate, temperature and blood pressure, due to a 4 h advancing shift in the rest-activity synchronizer, is well documented. In the first hypertensive patient a circadian rhythm is demonstrated also in blood pressure during two non-consecutive months. No difference is detected in both mesor and amplitude of blood pressure and a full resynchronization of the acrophase is achieved when a 1 h delaying shift in the rest activity synchronizer is imposed. In the second patient a well reproducible rhythm of systolic blood pressure and a low noise/signal ratio is documented by the serial section display. In the third patient the 'lability' of hypertention seems mainly due to salt sensitivity, as documented by the significant lowering of the mesor in the second experimental span, when a lowering of only 30 mEq/day in salt intake is imposed. The serial section better documents the salt-sensitivity of this patient, during a span when loading and depressing of salt intake is imposed. In the last patient the prompt effect of therapy in lowering blood pressure within normal range is well documented by serial section with 3 day interval. A possible effect of masking the circadian rhythm of blood pressure, due to therapy, is inferred by the serial section display with an interval of the same length (33 days) as the subspan without therapy. The possibility of prevention in the hypertensive disease is discussed, with the aim of autorhythmometry and statistical methods employed in this paper.

[Hydrodynamic and radiologic examination of the common bile duct]

The operative study of the common bile duct was carried out with the hydrodynamics methods (flow and resting pressure) in 433 patients and with the operative cholangiography in 383 patients. The hydrodynamics explorations pointed-out a margin of mistake due to falses positives and negatives of the 2.7% and the operative cholangiographies of the 8.6%. The association of both methods, hydrodynamics and radiologycs, allowed us to estimate that the diagnostic mistake is reduced to 0%. It is established in this work the necessity of carring out the flow, the measure of the resting pressure and the cholangiographies; in all the patients that are operated on the biliary tract because the diagnostic accuracy is the 100%. It is discussed the value of the diameter of the common bile duct for affirming the eventual existence of obstruction of the lower part of the common bile duct and the values are correlated, measured in mm., with pathological founds. It is considered the value of the hydrodynamics methods in the diagnostic of the stenosis of the sphincter of Oddi.

On a mathematical model for the analysis of the glucose tolerance curve

Three hundred and seventeen oral glucose tolerance curves have been analyzed by a mathematical model (Ackerman's model).

By application of the model to continuous venous infusion the validity of the Ackerman's hypothesis on the glucose intestinal absorption has been confirmed. The results demonstrated that the intestinal absorption rate of glucose was not statistically changed in diabetes mellitus, but decreased with age.

The period of curve T, which characterizes the glucose-insulin feed-back, the glucose fasting level and the coefficient α, which characterizes insulin removal rate independent of blood glucose and the decrease of blood glucose independent of insulin, resulted in significant differences between normal and diabetic subjects. The error involved in this method was about 7.5 per cent.