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Biomedical subjects

S Romano

Publications and source records attributed to S Romano.

At least 235 records · Page 13Linked to original sources
PubMedDate not supplied

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.

Adult↗
PubMedDate not supplied

Limitations of applicability of current calibration procedures for respiratory inductive plethysmography.

Repeatability of calibration of the respiratory inductive plethysmograph and its stability with time were investigated in young healthy subjects. Eight were submitted to sequential runs of calibration-validation by simultaneous equation (SEM) and least squares methods (LSM) (30 in all): in five subjects, after an initial acceptable calibration, accuracy and precision were repeatedly checked over three hours (a total of 50 trials). Although mean errors for the whole sample seemed acceptably low (7.6%, SD 7.0 for SEM; 7.3%, SD 7.3 for LSM), a marked inconsistency of apparently comparable calibrations and a wide variability of results along but independently of the time in steady conditions (ranging up to 30%) were discovered. An analysis of factors interfering with the response of the equipment was made. The unreliability of the current calibration procedure was related to the fact that in most cases the calibration line derived by the change-in-posture technique, as currently applied, may not be adequately representative of the full range of relationships between the participant variables, as they occur in the selected posture. To overcome this difficulty, two suggestions are made: a) prolong the calibration procedure so as to use more data points, and b) investigate alternative procedures of calibration in any one position.

Adult↗
PubMedDate not supplied

Pepsinogen gastrin mesor ratio: a potential simple marker for gastric secretory function.

As compared to control subjects, patients with duodenal ulcer show decreased levels of serum G and increased levels of serum Group I pepsinogen (PGI). On the other hand, pregnant women in their third trimester show an increased level of serum G and decreased levels of serum PGI. Gastrin stimulates gastric secretion and has a trophic effect on the parietal cells. Concentrations of PGI in serum reflect the capacity of pepsin-secreting cells which are, in turn, closely related to the parietal cell mass. Pepsinogen/G ratio (PGI/G) could represent the effective acid-peptic secretory capacity. This study suggests that for screening and clinical purposes PGI/G ratio provides a good potentially discriminatory marker of gastric secreting capacity reliably correlating and improving the diagnostic significance of single G and/or PGI serum levels.

Adolescent↗
PubMedDate not supplied

The maternal 24-h blood pressure (BP) profile as a predictor of fetal distress.

No mention is made of any aspect of BP bioperiodicity, among current clinical criteria for diagnosing pregnancy-related hypertension. The abnormal BP, based on a single unqualified measurement, is accepted and utilized as a clinical feature to identify pregnancy at risk. Systolic, diastolic and mean arterial blood pressure were measured every 15 min for 24 h in 5 women (2 non pregnant clinically healthy subjects, 1 clinically healthy subject in her third trimester of pregnancy, 1 presenting mild and 1 severe toxiemia, also in their third trimester of pregnancy) by an automated BP recording apparatus (Dynamap). All variables, analyzed by the single cosinor method, exhibited statistically significant circadian rhythms. A high amplitude could nullify the time-unqualified usual range. The change in circadian amplitude precedes an overt mesor hypertension and constitutes a tool for earlier detection of fetal distress.

Adult↗
PubMedDate not supplied

An attempt to establish early signals of peripheral arterial disease (PAD): the use of rhythm's parameters of peripheral blood flow (RF).

Rhythm parameters of peripheral arterial rest blood flow (RF) as a potential predictor of peripheral arterial disease (PAD) have been investigated. Three groups of subjects have been studied: a. six apparently healthy subjects; b. seven high risk (hypertension, diabetes, hypercholesterolaemia, hypertriglyceridaemia, erythrocytosis) subjects; c. four occlusive PAD selected patients with one 'pre-symptomatic' leg. RF has been measured by 'strain-gauge plethysmography' every min for 25 min, 4 times/day. Right fore-arm, right leg and left leg have been assessed. Data have been analyzed by 'single and population mean cosinor'. Significant circadian rhythms have been detected in apparently healthy subjects. Mesor and amplitude can differ according to single individual's area. Mesor is higher in upper limb. RF circadian rhythm parameters differ in subjects with various vascular risk load. Sometimes, PAD-symptomatic limb shows higher mesor than pre-symptomatic one, suggesting conditions of reactive post-ischemic hyperemia or a role of RF in PAD. Circadian dyschronia can be detected in PAD limbs but also in high risk subjects, perhaps an example of chronoprotopathology. These results suggest the possibility of a clinical use of RF rhythm parameters as predictors of vascular protopathology.

Adult↗
PubMedDate not supplied

Prazosin-induced haemodynamic modification in human hypertension. Evidence from strain-gauge plethysmography. Part II.

Three hypertensive in-patients responsive to a single oral administration of 1 mg prazosin were studied to compare the delays of drug effect on peripheral blood flow (PBF), heart rate (HR) and blood pressure (BP). Arm PBF was measured by venous occlusion strain-gauge plethysmography in a long run session (lasting at least 2 hours) every 5 - 10 minutes. HR and BP were measured accordingly, by conventional methods. The delays of the effect were compared by a cross correlation function of HR, systolic and diastolic BP versus PBF. The results show both advance and delay of HR increase as compared with PBF increase, suggesting some independent mode of action of prazosin at peripheral (vasodilation) and central (HR) level. BP decrease is instead always delayed with respect to PBF increase, by a variable amount (10 - 60 minutes) and with some difference in time response to systolic and diastolic BP, suggesting some independent feed-back loops controlling systolic and diastolic BP adjustment due to primary vasodilation effect.

Blood Pressure↗
PubMedDate not supplied

Prazosin-induced vasodilatation of muscle blood vessels in human hypertension. Evidence from strain-gauge plethysmography. Part I.

The fall of blood pressure provoked in hypertensive men by a single oral dose of 1 mg of prazosin is associated with an increase of forearm muscle blood flow. This phenomenon may be demonstrated by a sequence of strain-gauge plethysmographic measurements, taken at regular intervals (5-10 minutes), before and during the action of the drug, lasting more than 2 hours.

Blood Pressure↗
PubMedDate not supplied

[Clinical considerations in the use of nifedipine in patients with "HELLP syndrome"].

The authors report eleven cases of patients having pregnancy induced hypertension, and two cases of patients having severe pregnancy induced hypertension complicated by thrombocytopenia, and elevated liver enzymes. Nifedipine has been used in treatment of blood hypertension. Moreover, nifedipine appeared to reverse thrombocytopenia and serum liver enzymes. The authors discuss the significance of Hellp syndrome (haemolysis, elevated liver Enzymes, and low platelet count).

Adult↗