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Biomedical subjects

P Cugini

Publications and source records attributed to P Cugini.

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

Severity of human hypertension in relation to the age in which high blood pressure makes its presumptive appearance.

PURPOSE: The present study investigates the properties of blood pressure (BP) circadian rhythm (CR) in newly-diagnosed hypertensives (NDH) as a function of the chronological age in which hypertension became manifest. MATERIALS AND METHODS: The study was performed on 141 NDH (71 males and 70 females, ranging in age from 24 year to 79 years), who were monitored in their 24-h BP via a non-invasive, ambulatory, automated recorder. The relation between the properties of BP CR and the age of the development of hypertension was investigated via the Clinospectror method, a trend analysis (periodic-linear regression method) for rhythmic biophenomena. RESULTS: A trend was detected for each one of the three properties of BP CR in relation with the age in which high BP made its appearance. As a matter of fact, the daily mean level (mesor) of BP CR was seen to be progressively less pronounced. The amplitude was found to show a progressive increment of its extent. The acrophase was seen to show a progressive antemeridian rotation of its timing. CONCLUSIONS: These trends suggest that hypertension tends to be less severe when its development occurs in subjects older in age. Such a less pronounced severity is, however, accompanied by a more pronounced oscillation of BP values during the 24-h of the day. Such a higher circadian variability, in turn, tends to show its highest expression during the morning hours of the day.

Adult↗
PubMedDate not supplied

The temporal bases of medicine: short notions of chronobiology.

The experimental observation has clarified that the majority of biological functions show a pattern of periodic type. Chronobiology was born as the discipline devoted to investigate the periodicity in biological phenomena, Time being regarded as a systematic variable of the dynamism in living matter. The present article provides short notions of this discipline, regarding the classification and meaning of biological rhythms, and concerning the methods for analyzing the periodicity in biosystems.

Chronobiology Phenomena↗
PubMedDate not supplied

[Circadian rhythm of the renin-angiotensin-aldosterone system: a summary of our research studies].

The renin-angiotensin-aldosterone system (RAAS) is characterized by a circadian rhythm (CR) whose acrophase is detectable early in the morning. The prorenin and angiotensin converting enzyme (ACE) show a CR as well. However, while the prorenin is in phase with the RAAS the ACE shows its circadian acrophase in the afternoon suggesting a negative feed-back. The RAAS CR is influenced by many factors. Its mesor is modified by sodium intake. The physical activity and rest affect both the mesor and acrophase. The variations in mesor amplitude and acrophase in aged subjects are conditioned by sex and physical activity. Moreover, the RAAS CR seems to be influenced by the race. In addition, it is abolished by the beta-adrenergic blockade, suggesting the existence of an adrenergic clock. Interestingly, the RAAS CR seems not to be a pacemaker for the blood pressure CR, whose acrophase is early in the afternoon. The RAAS CR is not substantially modified has in essential hypertension. However, the CR of plasma renin activity is disappeared in the low-renin essential hypertension, while the CR of plasma aldosterone is detectable. On the contrary, the aldosterone CR is not detectable in ascitic liver cirrhosis; but, it is restored when the ascites is removed by peritoneal-jugular shunt. No significant variation of the RAAS CR seems to occur in obesity and Cushing's syndrome. The RAAS CR has disappeared in Conn's disease as well as in Bartter's syndrome and Liddle's syndrome. The administration of indomethacine in Bartter's syndrome and of triamterene in Liddle's syndrome is able to restore the RAAS CR. Finally, the RAAS CR is not detectable in the heart or kidney transplanted patients; such a phenomenon could be attributed to cyclosporine and corticosteroids administration and to the denervation of the transplanted organs.

Circadian Rhythm↗
PubMedDate not supplied

Analysis of the chaotic component of the sinusal R-R intervals as a tool for detecting a silent cardiac dysautonomia in type 2 diabetes mellitus.

This study explores the heart rate (HR) variability (V) in order to detect whether the chaotic component of the sinusal R-R intervals (SRRI) can be interpreted as an early indicator of a silent cardiac neurovegetative dysautonomia in apparently uncomplicated Type 2 diabetic patients (DP). The SRRI were provided by the 24-h Holter ECG of 10 Type 2 DP (5 M and 5 F, mean age = 41 +/- 5 years). Control data were obtained by the 24-h Holter ECG of 10 clinically healthy subjects (CHS, 5 M and 5 F, mean age = 38 +/- 6 years). The chaotic component of HRV was investigated via the correlation dimension (CD) analysis (A) of the SRRI, performed per each hour of the ECG recording. The hourly-qualified series of SRRI, HR and CD index (I) were, in turn, analyzed via methods of conventional statistics and chronobiology, the latter ones for assessing the circadian rhythm (CR). The CDI CR was found to peak during the night in CHS, and to be unphysiologically rotated to the diurnal hours of the day in Type 2 DP. The diurnal inversion of the CDI CR in Type 2 DP suggests that the chaotic component of HRV shows an abnormal rhythnic pattern over the day-night period. Considering that the investigated Type 2 DP were lacking of documentable signs of cardiac neuropathy, it is hypothesized that the diurnal phase of shift CDI CR might be a potential indicator of a silent autonomic cardiac dysfunction in Type 2 DP. Such a hypothesis waits for further confirmations.

Adult↗
PubMedDate not supplied

Eating behaviour: investigation on the recursive components of hunger sensation by iterative rhythmometry.

The periodic components of hunger have been investigated in the spectrum of ultradian and circadian rhythms by means of iterative rhythmometry analysis, a method for resolving harmonic components in time series data. The cyclical scanning has been applied in human subjects with eating disorders associated with leanness, ponderosity and obesity. The sensation of hunger was rhythmometrically resolved into ultradian and circadian components which are peculiar for the group investigated. Harmonic modelling can be used on an individualized basis for group-specific configurations and, on that basis, for unphysiologic patterns. A comparison with the rhythmometric model of healthy subjects may have a practical use in identifying and manipulating behavioural disorders in the propensity to eat.

Adolescent↗
PubMedDate not supplied

Preoperative selection for curable renovascular hypertension.

Clinical research has defined the criteria for identifying "curable" renovascular hypertension. The prediction is based on the measurement of plasma renin activity in peripheral veins, renal veins, and the aorta. Renin profiles can be examined with the method of Laragh and coworkers (the so-called incremental method), in which values for plasma renin activity are incorporated into formulas to compute indexed parameters. A score is attributed to each index and the prediction is based on the final score. Because the identification of curable renovascular hypertension is made according to numerical rules, the method is easily transformed into a computer-assisted process. The program is written in BASIC, and it is short enough to run on a personal computer.

Diagnosis, Computer-Assisted↗
PubMedDate not supplied

Chronopathology for angiotensin converting enzyme circadian rhythm in migraine.

This investigation is devoted to explore the 24-h patterns of serum angiotensin converting enzyme (ACE) activity in clinically healthy subjects and migraine patients taking as reference the adrenal cycle. Time data series have been analyzed by means of chronobiologic procedures. The biostatistical approach has documented that the enzymatic activity of serum ACE in clinically healthy subjects changes with a circadian periodicity. The chronobiologic approach has additionally revealed that the enzymatic activity of serum ACE activity is circadianly aperiodic in migraine patients, while plasma cortisol shows a preserved cyclicity along 24-h scale. The aperiodicity suggests that the enzymatic degradation of the ACE-dependent substrate is inappropriate over the 24-h span.

Adult↗
PubMedDate not supplied

[Usefulness of long-term monitoring of neonatal arterial pressure].

30 newborns were studied, whose systolic arterial pressure has been controlled every 30 minutes 48 hours long, with oscillometric automatic technique. The resulting average of oscillation was 45.1 +/- 12.8 mmHg for systolic pressure and 36 +/- 11.4 mmHg for diastolic pressure. Wide pressure oscillations, you can find in some newborns, could be related with the development of a future pressure hypertension, and therefore a long term pressure monitoring would turn to a real useful test to single out future hypertensive subjects.

Blood Pressure↗
PubMedDate not supplied

Day-time changes for pituitary-thyroid hormones denote a rhythmic structure not detectable in elderly subjects.

The day-time concentrations of TSH, T3, T4, FT3 and FT4 were investigated in clinically healthy volunteers, 20 young individuals, aged from 20 to 27 years, and 12 elderly subjects, aged from 70 to 81 years. Nocturnal sampling was purposely avoided in order to eliminate the interindividual differences in sleep patterns. The day-time series were analysed by means of cosinor analysis to interpolate the best-fitting sinusoidal wave that covers the day-night period. The reconstruction of the circadian sinusoidal wave was validated for TSH, T3, T4, FT3 and FT4 in young subjects, and, with limitation, for T4 in elderly individuals. The findings suggest that the day time patterns of TSH, T3, FT4 and FT3 in elderly subjects are characterized by a dyschronism that is not detectable in young subjects. The investigation of the day-time concentrations is suggested as a cost-effective tool for exploring the circadian cycle of the pituitary-thyroid hormones in aged people.

Adult↗
PubMedDate not supplied

Sodium restriction amplifies and propranolol loading inhibits circadian rhythm of plasma renin-angiotensin and aldosterone.

Five male and 5 female clinically healthy volunteers, 17-37 years of age, gave systemic venous blood at 0600, 0800, 1200, 1800, 2000 and 0000 for RIA of (supine values) plasma renin-angiotensin (PRA) and aldosterone (PA) under 4 conditions: a. unrestricted sodium intake, no treatment; b. unrestricted sodium intake and 40 mg propranolol per os every 6 h; c. sodium restriction, no treatment; d. propranolol loading on sodium deprivation. Cosinor methods were used for data analysis. Sodium restriction amplifies the circadian rhythms of PRA and PA, whereas propranolol loading inhibits these same rhythms on a unrestricted sodium intake, but much less so under conditions of sodium deprivation. The propranolol-induced inhibition of the circadian rhythms investigated on a unrestricted sodium intake suggests that the beta-adrenergic system is an effective mechanism coordinating the circadian rhythmic functions investigated. The persistence of the rhythms in sodium-depleted subjects under pharmacological blockade of beta-adrenoreceptors is in keeping with the concept that a second mechanism of the circadian rhythms examined is located in the sodium-sensitive macula densa cells of the renal distal tubule.

Adolescent↗
PubMedDate not supplied

Chronobiology of blood pressure in childhood: implications for tracking.

Chronobiology, in its methodological evolution, developed data series analyses paying particular attention to blood pressure (BP), because of the importance of this biorhythmic variable for assessing the risk of developing hypertension. An example of the potentiality of the chronobiologic procedures is given in the present report which deals with the inferential analysis of the BP 24-h patterns in 3-12 year-old children. By using the chronobiologic methodology, time-qualified standards for BP are calculated. Rhythmometric parameters for circadian rhythm of systolic and diastolic components of BP are also computed. Data presented are a tangible outcome for emphasizing the introduction of chronobiology in epidemiology and pediatrics in order to optimize the primary prevention and care of hypertension taking as reference the chronobiologic standards of BP.

Biometry↗