Changes in TSH levels in athyreotic patients with differentiated thyroid cancer during levothyroxine therapy: influence on dose adjustments

PURPOSE

The aim of the study was to describe the spontaneous TSH level variations and levothyroxine dose adjustments in athyreotic patients with differentiated thyroid cancer (DTC) in real-life practice.

METHODS

Patients with DTC were retrospectively evaluated at a tertiary referral center between October 2006 and November 2013. Hormone measurements (TSH and FT4 serum levels), L-T4 prescription information (dose per kg per day) and other medications were recorded at 1 month and 3, 12, 24, 36 and 48 months after primary treatment (surgery ± radioiodine therapy).

RESULTS

The cohort was composed of 452 patients; about 20% of patients with stable levothyroxine dose have clinically meaningful spontaneous TSH variations (defined as ΔTSH > 2 mcUI/mL) at yearly follow-up visit. Furthermore, about 25% of athyreotic DTC patients with stable dose have a ΔTSH > 1.5 mcUI/mL and about 40% a ΔTSH > 1 mcUI/mL during each follow-up visit. We further investigated whether this TSH variation would lead to subsequent dose changes. About 19.9-37.7% of DTC patients on stable LT4 dose on the previous visit had their levothyroxine dose reduced, while 7.8-14.9% increased due to TSH variations. We further evaluated the decision to change the dose in relation with the age-specific TSH range. Up to 77.2% of patients had their dose adjusted due to TSH falling below the age-specific range.

CONCLUSIONS

Spontaneous serum TSH variations determine levothyroxine replacement therapy in athyreotic patients with DTC, requiring multiple dose changes.

Enhanced Soluble Serum CD40L and Serum P-Selectin Levels in Primary Aldosteronism

Primary aldosteronism (PA) is one of the most frequent forms of secondary hypertension, associated with atherosclerosis and higher risk of cardiovascular events. Platelets play a key role in the atherosclerotic process. The aim of the study was to evaluate the platelet activation by measuring serum levels of soluble CD40L (sCD40L) and P-selectin (sP-selectin) in consecutive PA patients [subgroup: aldosterone-secreting adrenal adenoma (APA) and bilateral adrenal hyperplasia (IHA)], matched with essential hypertensive (EH) patients. The subgroup of APA patients was revaluated 6-months after unilateral adrenalectomy. In all PA group, we measured higher serum levels of both sP-selectin (14.29±9.33 pg/ml) and sCD40L (9.53±4.2 ng/ml) compared to EH patients (9.39±5.3 pg/ml and 3.54±0.94 ng/ml, respectively; p<0.001). After removal of APA, PA patients showed significant reduction of blood pressure (BP) values, plasma aldosterone (PAC) levels and ARR-ratio, associated with a significant reduction of sP-selectin (16.74±8.9 pg/ml vs. 8.1±3.8 pg/ml; p<0.01) and sCD40L (8.6±1 ng/ml vs. 5.24±0.94 ng/ml; p<0.001). In PA patients, we found a significant correlation between sP-selectin and sCD40L with PAC (r=0.52, p<0.01; r=0.50, p<0.01, respectively); this correlation was stronger in APA patients (r=0.54; p<0.01 r=0.63; p<0.01, respectively). Our results showed that PA is related to platelet activation, expressed as higher plasma values of sCD40L and sP-selectin values. Surgical treatment and consequent normalization of aldosterone secretion was associated with significant reduction of sCD40L and sP-selectin values in APA patients.

[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.

Cardiac troponin I in acute coronary ischemic syndromes. Epidemiological and clinical correlates

The present study was aimed to investigate the variability of cardiac troponin I (cTnI) in the first week of acute myocardial infarction (AMI) course with regard to some epidemiological and clinical parameters and in patients with non-AMI acute coronary ischemic disease. Serum cTnI was assayed in 82 patients, 42 affected with AMI and 40 with non-AMI acute coronary ischemic disease, on admission in coronary care unit, within 6 h after the onset of symptoms, and, in AMI group, on 24 and 48 h and 7th day of illness course. cTnI is increased within the first 6 h, remaining above normal until 7th day. However, some distinctive features in the subgroups scheduled for this study are present. (1) The mean values of cTnI in AMI patients who died, >60 years old and with anterolateral necrosis are constantly higher than in survivors, <60 years old and with inferoposterior necrosis, respectively. (2) The cTnI concentration is already returned in normal range at 7th day of illness course in survivors and in patients with inferoposterior AMI. (3) The 24-h peak level of cTnI is significantly higher in fibrinolysed than in patients who didn't undergo fibrinolysis. (4) A direct correlation between the cTnI value and the Killip class is present either in the whole group or in any subset of patients and the progressive decrease of the cTnI concentration along the AMI course doesn't occur in Killip>2 group. (5) cTnI is higher in unstable than in stable anginous patients and normal subjects but not in stable angina with respect to healthy controls.

CONCLUSIONS

(1, 2) The less increase and the early return in normal range of cTnI serum levels which occur in AMI subgroups with a better prognosis could be regarded as favourable prognostic signs. (3) The persistent higher values of cTnI in fibrinolysed subjects being associated with the angiographic finding of patent coronary arteries, it can be suggested that the large and persistent relase of cTnI from myocardium represents a reliable biochemical marker following the wash-out associated to a successful reperfusion. (4) The persistent increase of cTnI in AMI patients with advanced Killip class suggests that the high cTnI values are not only a strong index of myocardial necrosis but also of ongoing myocyte injury and hemodynamic impairment predictive of poor outcome. (5) The hypothesis can be reasonably advanced that the higher values of cTnI in unstable angina are due to focal areas of myocardial necrosis undetectable by the conventional serum markers or to a clinically silent AMI occurred in the week or so before in-hospital admission.

[Relationship among VIP plasma levels, esophageal dysfunction, and microcirculation in systemic sclerosis]

BACKGROUND

Recent studies suggest that esophageal dysmotility occurring in systemic sclerosis might be caused by neurotransmitter levels decrease. The aim of the present study is to value VIP plasma levels, and to relate them with the pressure of the inferior esophageal sphincter (IES) and the capillaroscopy score in a group of patients affected by Systemic Sclerosis (SSc).

METHODS

Eleven subjects affected by SSc (eight male and three female, age from 30 to 72 years old) have been studied through esophageal manometry, capillaroscopy and VIP plasma levels evaluation. Fifteen healthy volunteers, as control group, have been enlisted.

RESULTS

Our results show a decrease of VIP plasma levels in patients with SSc compared with control group. The difference between two groups has statistical significance (p < 0.01). Capillaroscopy has shown remarkable microcirculatory impairment and the esophageal manometry proved a decreased IES pressure. The scores of capillaroscopy, VIP plasma levels and pressures of IES have been compared and it has been observed that there is a relationship between VIP plasma level and pressure of IES.

CONCLUSIONS

VIP plasma levels decrease enhances the role of the autonomic disorder in SSc and may contribute to produce the alteration of vascular tone as well as the gastroenteric musculature dysfunction.

[Vasoactive intestinal peptide in heart failure]

BACKGROUND

The aim of our study was to investigate the pathophysiological role of the vasoactive intestinal peptide (VIP), a vasodilating neuropeptide with positive inotropic and chronotropic properties, in heart failure.

METHODS

The study was carried out in 35 patients with heart failure due to dilated cardiomyopathy, who underwent a peripheral venous blood sample for radioimmunoassay of VIP within the first in-hospital day.

RESULTS

The plasma concentration of VIP: 1) is not higher than normal in the whole group of patients with heart failure; 2) is higher in younger than in elderly healthy subjects but does not significantly change in relation to age in heart disease patients; 3) is higher in elderly (> 60 years) but not in younger (< 60 years) patients compared to healthy subjects of the same age; 4) is higher in NYHA functional class 2 than in NYHA functional class > 2 groups and in normal subjects; 5) is not correlated with echocardiographic parameters; 6) does not significantly change with respect to the etiology of dilated cardiomyopathy.

CONCLUSIONS

The plasma concentration of VIP in heart failure is conditioned by some epidemiological and clinical variables. Unlike the healthy group, differences are not detectable with respect to the age of patients; thus, in elderly heart disease subjects the neuropeptide productive potentiality is preserved. Taking into account the physiological properties of VIP, its plasma increase in the initial phase of heart failure can be reasonably regarded as a further mechanism to restore the compromised hemodynamic balance. Its decrease, related to worse clinical conditions, could be due to a progressive depletion from the pre-synaptic nerve endings and to a deficiency in the neurogenic productive capacity of the molecule.

[Troponin I in acute ischemic cardiopathy]

BACKGROUND

The present study was aimed at investigating cardiac troponin I values in the first week of acute myocardial infarction and in non-infarct acute coronary ischemic syndromes.

METHODS

Eighty-two patients, 42 with acute myocardial infarction, 10 with stable angina and 30 with primary unstable angina, were enrolled in the study. Blood was collected within 6 hours of symptom onset and, in the group with acute myocardial infarction, after 24 and 48 hours, and on day 7.

RESULTS

Serum troponin I increased within the first 6 hours of myocardial infarction, reached the peak after 24 hours, at 48 hours it decreased, and remained above the normal range until day 7. However, troponin I values 1) were constantly higher in patients who died, in those > 60 years old and in those with antero-lateral necrosis than in survivors, in those < 60 years old and in those with infero-posterior necrosis, respectively; 2) returned to normal range on day 7 in survivors and in patients with infero-posterior acute myocardial infarction; 3) were significantly higher in fibrinolysed patients than in those who did not undergo thrombolysis; 4) were higher in patients classified as Killip class > 2. Serum troponin I values were in the normal range in non-infarct acute coronary ischemic syndromes, but were higher in unstable than in stable angina.

CONCLUSIONS

The lesser increase and the early return to the normal range of cardiac troponin I levels in the subgroups of patients with myocardial infarction having a better clinical course could be regarded as a favorable prognostic sign. Since the persistent higher values of cardiac troponin I in fibrinolysed subjects are associated with the angiographic finding of patent coronary arteries, it can be suggested that the large and persistent post-thrombolysis release of cardiac troponin I from the myocardium represents a biochemical marker of a successful reperfusion. The persistent high cardiac troponin I values in patients with advanced Killip class suggest that the neuropeptide is an index of ongoing myocyte injury and hemodynamic impairment as well. The higher values of cardiac troponin I in unstable angina are probably due to focal areas of myocardial necrosis undetectable by conventional enzymatic serum markers.

Age-related changes in blood pressure twenty-four-hour pattern in normotensive subjects of two populations

OBJECTIVES

This study investigates the systolic (S) and diastolic (D) blood pressure (BP) 24-h pattern in normotensive healthy subjects belonging to two populations characterized respectively by a "non-salt culture" (Italian subjects) and a "salt culture" (Japanese subjects) in their dietary salt intake (4-6 g/day in Italians vs 10-12 g/day in Japanese). The comparison was performed by taking into consideration the within-day variability (WDV) and circadian rhythmicity (CR) of BP with respect to age.

MATERIALS AND METHODS

Subjects investigated were 862 normotensive healthy subjects (308 Italians and 554 Japanese), stratified by age from 16 to 75 years, who volunteered for a noninvasive BP monitoring in an ordinary day of their life. The SBP and DBP time series were analyzed via conventional parametric statistics as well as chronobiological procedures.

RESULTS

The biometric estimates demonstrate that BP changes in its WDV and CR as a function of age in both populations. Despite the difference in their habitual salt intake, the age-related changes in BP WDV and CR result to be almost comparable at the cross-sectional contrasts, giving origin to age-related trends for SBP and DBP which are significantly parallel.

CONCLUSIONS

The comparability of BP WDV and CR in the two populations with a substantial difference in salt intake suggests that the normotensive status in human races is realized despite the difference in their habitual salt intake. This implies the ancestral development of mechanism(s) of adaptation to the possible "sodium luxus consumption". Although the adaptive mechanisms which provide a normotensive regimen under different conditions of sodium intake are almost unexplored, the racial adaptation to dietary salt constitutes, however, the initial condition for the cause-effect nexus between dietary salt intake and hypertension in human populations.

[The concept of "preclinical arterial hypertension" - in light of non-invasive, ambulatory blood pressure monitoring]

In clinical medicine it is possible to find subjects who show initial signs of hypertensive damage being normotensive at the "casual" sphygmomanometry. In order to verify whether or not these subjects are "true normotensives", it was applied the noninvasive ambulatory monitoring of blood pressure (BP). Five studies were performed: I. Normotensives with initial hypertensive retinopathy; II. normotensives with initial hypertensive cardiohypertrophy; III. Normotensives with initial hypertensive cardiohypertrophy of the transplanted heart; IV. Normotensive pregnant women with altered uterine blood flow; V. Normotensive pregnant women with intrauterine growth retardation. From all the studies, it was possible to derive that the subjects were all true normotensive. However, they were characterized by BP values on average higher than those of their controls, but below the reference limits given by WHO. Because of the relative elevation of BP, it was possible to argue that there exists a BP regimen which is potentially dangerous for the target organs, even though there is no evidence of manifest arterial hypertension. Such a hemodynamic condition causing hypertensive cardiovascular damage was defined "arterial pre-hypertension".

Who are the non-dippers? A better definition via the blood pressure circadian rhythm

OBJECTIVE

The non-dipping phenomenon (NDP) can be better interpreted when considering that blood pressure (BP) shows a within-day variability which is the expression of a circadian rhythm (CR).

PATIENTS AND METHODS

The NDP was investigated at the light of the BP CR by analysing the ambulatory BP monitoring of 298 essential hypertensive patients (EHP), 84 secondary hypertensive patients (SHP), as well as 93 normotensive subjects (NS). According to the rhythmometric validation, the investigated subjects were defined "rhythmic" (R) or "non-rhythmic" (NR).

RESULTS

The non-dippers (ND) were found among not only the EHP (14%) and SHP (27%) but also the NS (16%). The percentages of R ND were 9%, 4% and 20%, respectively in EHP, SHP and NS. The R ND were characterized by a nocturnal phase-shift (100% in NS), associated with an amplitude increase (50% in EHP) or a mesor increase (50% in EHP; 100% in SHP) in BP CR. The NR ND were characterized by an amplitude almost negligible (100% in NS) associated with a mesor increase (100% in EHP; 100% in SHP).

CONCLUSIONS

The detection of a NDP associated with a rhythmicity suggests that the criterion with which the ND are identified cannot be used for making inferences on the BP CR in HP or NS. The rhythmic characteristics in ND suggest that the rhythmometric analysis is fundamental for identifying the abnormal time structure of BP 24-h values in the presence of the NDP.

Construction of age-related reference limits for 24-h blood pressure pattern

Blood pressure (BP) is recursively variable during the day-night cycle because of a physiological circadian rhythm. The aim of this study is, therefore, to show how to construct the population reference limits (desms) for BP in its time varying 24-h pattern, starting from a small sample, in order to facilitate their use in a local context. The sample for standardization comprised 427 clinically healthy subjects (211 males and 216 females), ranging in age from 16 to 100 years, attending their routine activities. The procedure begins with the statistical biometry related to the sample, and proceeds with the computation of the BP desms related to (1) the time-qualified discrete values; (2) the parameters of circadian rhythm; (3) the daily pressure load. The pertaining rules are explained step by stop, allowing each one to prepare the proper local desms for BP 24-h pattern. These standards may be useful for validating the individual BP monitoring according to the upper limits of the circadian physiological variability in the diagnostic procedure for identifying hypertensive subjects.

[The heart rate variability indices and the circadian rhythm of the hourly heart rate: 2 prognostic indicators of mortality and malignant ventricular arrhythmias in patients with a myocardial infarct]

The aim of this study was to investigate the circadian variability of heart rate in acute myocardial infarction (AMI) in identifying patients at high risk for malignant ventricular arrhythmias (MVA) and sudden death within 1 year of the acute event. The investigation was carried out in 43 patients, who underwent 24-hour Holter monitoring within 3 months of AMI. Besides the time domain indexes of heart rate variability (SDNN, SDNN index, pNN50, rMSSD), the circadian rhythm of hourly total beats (HTB) and hourly qualified beats (HQB) has been analyzed by the Cosinor method. The AMI patients with MVA and those with MVA who died within 1 year the acute event showed SDNN, SDNN index and pNN50 values lower than subjects without MVA and survived patients with MVA, respectively; the individuals with AMI at high risk for MVA and for sudden death had an SDNN value < 105 ms and 50 ms, respectively. The circadian rhythm of HTB and HQB was statistically validated only in the group without MVA; patients without the circadian rhythm of HTB and HQB showed a higher mortality rate within 1 year of AMI, and the majority was in the group with MVA. The contemporary evidence of an SDNN value < 105 ms and the lack of HTB and HQB circadian rhythm increased sensitivity for identifying patients with MVA to 75%. On the other hand, the contemporary evidence of an SDNN value < 50 ms and the lack of HTB and HQB circadian rhythm increased sensitivity for identifying patients who died within 1 year of AMI to 100%. In conclusion, the assayed methods seem to be both useful and complementary in identifying patients at high risk for MVA and sudden death within 1 year of AMI.

The relevance of continuous blood pressure monitoring in examining the relationship of memory efficiency with blood pressure characteristics

The study of the relationship between hypertension and cognitive decline is characterized by various difficulties of realization and, as a consequence, by incongruent results. One of the reasons for these difficulties may be explained by the occasional method of measurement of blood pressure (once a day). This study presents the results obtained in 27 normotensive and mild hypertensive subjects of both sexes (ages between 20 and 77 years) with a continuous blood pressure monitoring for 24 h. A noninvasive sphygmomanometric technique was used employing a portable recorder programmed to take a measure every 30 min. Both objective and subjective measures of memory, measures of attention efficiency, and IQ were correlated to the blood pressure measures. Continuous monitoring data of blood pressure were analyzed according to a model that included a macroscopic descriptive analysis, a microscopic rhythmometric analysis, and a microscopic integrative analyses where the effects of the interaction between level and duration of excess and the time of the day when the excess eventually appeared were considered. Results evidenced no differences in cognitive efficiency between those subjects identified with the traditional occasional measurement of blood pressure as hypertensives of mild severity and the normal subjects. Cognitive efficiency of our subjects was found correlated, independently from the clinical diagnosis, with the time of peak and with the duration of excess of their blood pressure when the results of the analyses on the continuous monitoring of blood pressure were considered.

Effect of age and relation to mortality on serial changes of vasoactive intestinal peptide in acute myocardial infarction

Plasma levels of vasoactive intestinal peptide increase early after acute myocardial infarction (AMI) and are significantly higher during the first 2 weeks of AMI in survivors and younger patients (<60 years) than in those who died and in older (>60 years) patients. Data suggest that vasoactive intestinal peptide is involved in neuroendocrine activation occurring in AMI and could be regarded as a marker of the course of AMI.

[Neuroendocrine activation in acute myocardial infarction: state of the art and preliminary results on intestinal vasoactive peptide]

Acute myocardial infarction (AMI) is known to be associated with a complex neuroendocrine activation, especially concerning sympathetic and renin-angiotensin systems, cortisol, atrial natriuretic peptide and endothelin. Results of our study show that the vasoactive intestinal peptide (VIP), also, is early involved in the neuroendocrine activation occurring in AMI. Plasma concentration of VIP, significantly increased in AMI patients within 6 hours after the onset of chest pain, soon decreased and remained below than normal along the first week. At the 14th day of the AMI, plasma levels of VIP returned into the normal range. A significant increase of VIP plasma concentration is detectable in the first hours of AMI in survived as compared with died patients. The phenomenon seems to be a suitable process to provide an endogenous support to the ischemic heart and to counteract the negative effects of other neuroendocrine activated factors.

[The physiopathological role and prognostic value of the vasoactive intestinal peptide in acute myocardial infarct]

Aim of our study was to investigate the pathophysiological role of vasoactive intestinal peptide (VIP) in the neuroendocrine activation occurring in acute myocardial infarction (AMI). Plasma VIP concentration has been assayed in 30 patients with AMI, 22 males and 8 females, aged 41-82 years, without other important diseases. VIP plasma values, assayed on admission to the Coronary Care Unit, within 4-6 hours after the onset of chest pain, everyday for the first week and on day 14, were significantly higher in survivors and in patients aged < 60 years. VIP plasma concentration was not statistically correlated with CPK and CPK-MB. VIP seems to play a pathophysiological role in the neuroendocrine activation occurring in AMI. Low VIP plasma levels are associated with an unfavorable short-term prognosis. Moreover, it appears that VIP secretion is negatively influenced by aging.

Campodimele study: blood pressure and heart rate pattern in clinically healthy elderly subjects

Noninvasive ambulatory blood pressure (BP) monitoring is a developing method in clinical practice. Its interpretation needs reference standards stratified by age and gender. This study addresses ambulatory BP monitoring in elderly people with the purpose of quantifying the discrete and periodic variability of BP pattern over a 24-h period. The ABPM was performed in 92 clinically healthy subjects (45 men and 47 women) ranging in age from 76 to 102 years. The results refer to the time-qualified mean values with their dispersion, to the circadian rhythm with its parameters, and to the daily baric impact (BI) with its variability. The conclusion is drawn that BP preserves its nychtohemeral variability and circadian rhythmicity despite old age. The daily BP mean level and BI in older people in good health are comparable with those of young subjects, suggesting that humans surviving into old age are characterized by a eugenic control of their pressure regimen.

Twenty-four-hour pattern of atrial natriuretic peptide in heart transplantation: evidence for lack of circadian rhythm. Temporal inter-relationships with plasma renin activity, aldosterone and cortisol

We have investigated the circadian rhythm of plasma atrial natriuretic peptide in 13 stable output heart transplanted patients, all without evidence of histological rejection and cardiac impairment, following antirejection therapy with Cyclosporine, Azathioprine and Prednisone. The 24-h pattern of plasma renin activity, plasma aldosterone and plasma cortisol has been studied as well. All the investigated variables were assayed six times over the 24-h span. The circadian time-qualified data were analyzed by ANOVA and Cosinor method. The 24-h mean levels of atrial natriuretic peptide, plasma renin activity and plasma aldosterone are significantly increased, while the concentrations of plasma cortisol are reduced in the heart transplanted recipients. ANOVA detected a significant within-day variability of all these humoral variables only in healthy subjects. A statistically significant circadian rhythm was validated by Cosinor procedure for all the investigated molecules in healthy subjects but not in heart transplanted patients. In our opinion, the increase of atrial natriuretic peptide is a counterregulatory mechanism aimed to compensate the cyclosporine-mediated activation of the renin-angiotensin-aldosterone system. The disappearance of the plasma renin activity, aldosterone and atrial natriuretic peptide circadian rhythm can be ascribed to the constant activation of the renin-angiotensin-aldosterone system. The hypocortisolism is due, in our opinion, both to glucocorticoid therapy and increase of plasma ANP concentration.

Lack of circadian rhythm of plasma concentrations of vasoactive intestinal peptide in patients with orthotopic heart transplants

OBJECTIVE

To study the circadian pattern of plasma concentrations of vasoactive intestinal peptide (VIP) in patients with orthotopic heart transplants. Circulating VIP is known to have neural and immunological sources.

PATIENTS AND METHODS

13 patients with orthotopic heart transplants were studied 12-53 months (mean 31.8 months) after operation. All were haemodynamically compensated and had no histological evidence of rejection. They were being treated with cyclosporin, azathioprine, and prednisone. Ten healthy individuals were studied as controls. Circulating VIP was assayed six times within a 24h period. Time qualified data were analysed by ANOVA and the cosinor method. Student's t test for unpaired data and Bingham's test for cosinor-derived parameters were used for statistical comparisons.

RESULTS

Plasma concentrations of VIP were lower in the patients with orthotopic heart transplants than in the controls (p < 0.001). ANOVA and the cosinor method respectively showed a statistically significant within-day variability and circadian rhythm in the controls but not in the patients with heart transplants.

DISCUSSION

The low plasma concentrations of VIP in the patients with heart transplants could be the result of the lack of contribution by the cardiac VIPergic fibres, a reduction of VIP release by the pharmacologically suppressed immune system, the inhibitory effects of cyclosporin on neural function and humoral secretions, and the effects of negative feedback on VIP release of high concentrations of atrial natriuretic peptide. The lack of the circadian rhythm suggests a structural disorder, which should be further investigated.

Circadian rhythm of blood pressure and heart rate in cardiopathic patients before and after heart transplantation

The aim of this study was to investigate the natural history of the circadian rhythm of blood pressure (BP) and heart rate (HR) in 10 patients with heart failure (class IV of the New York Heart Association), who underwent heart transplantation because of primary congestive cardiomyopathy. The control group was 10 age-matched clinically healthy subjects. The BP and HR monitorings were performed before and after transplantation. Preoperatively, analysis of variance and cosinor methods validated the occurrence of a statistically significant BP and HR circadian rhythm in cardiopathic patients. Over the 4 days after surgery, both the cosinor method and serial section analysis were unable to validate a 24-h periodicity for BP and HR in patients with heart transplants. Six months after surgery, the BP and HR circadian rhythm was not detected as well. One year after transplantation, the BP and HR circadian rhythm was statistically validated. The recovery of the BP and HR circadian rhythm 1 year after heart transplantation can be regarded as a clinical sign of a reacquired susceptibility to neurovegetative chronoregulation.

Circadian rhythm of cardiac output, peripheral vascular resistance, and related variables by a beat-to-beat monitoring

This study aimed to explore the 24-h patterns of stroke volume, cardiac output, and peripheral vascular resistance along with other correlated variables, such as left ventricular ejection time, ejection velocity index, thoracic fluid index, heart rate, and blood pressure. The study was performed on 12 clinically healthy subjects by means of a noninvasive beat-to-beat monitoring using the thoracic electric bioimpedance technique associated with the automated sphygmomanometric recording. Time data series were analyzed by means of chronobiological procedures. The results documented the occurrence of a circadian rhythm for all the variables investigated, giving relevance to the beat-to-beat bioperiodicity of cardiac output and peripheral vascular resistance. Temporal quantification of the investigated variables may be useful for a better insight of the chronophysiology of the cardiovascular apparatus.

Effect of aging on circadian rhythm of atrial natriuretic peptide, plasma renin activity, and plasma aldosterone

Atrial natriuretic peptide (ANP) shows a nychtohemeral fluctuation and an age-related trend. The aim of this study was to explore the circadian rhythm of ANP as a function of age. Circadian rhythms of plasma renin activity (PRA), aldosterone (PA), and cortisol (PC) were explored as well. Twenty clinically healthy subjects, 10 young (20-25 yrs) and 10 elderly (65-75 yrs), were investigated, while recumbent, after synchronization to light-dark regimen and meal timing. Blood samples for RIA tests were collected six times during the 24-hr span. The chronobiologic analysis in young subjects demonstrated a significant circadian rhythm for all the investigated variables with an acrophase-timing located at 16.48 for ANP, 4.44 for PRA, 5.32 for PA, and 7.12 for PC. In elderly subjects we documented an important increase of 24-hr mean plasma levels but not a statistically significant circadian rhythm for ANP, and a decrease in mean value of PRA which maintained, however, a significant periodic 24-hr oscillation in parallel with PA and PC. The results in young subjects reinforce the concept that ANP plays physiologically an inhibitory role on the phasic secretion of renin. The lack of the circadian rhythm for ANP along with the divergent changes in ANP and PRA 24-hr mean concentration of elderly subjects both suggest that ANP exerts with advancing age only a counterregulatory role on the tonic rather than the phasic release of renin.

The circadian rhythm of atrial natriuretic peptide, vasoactive intestinal peptide, beta-endorphin and cortisol in healthy young and elderly subjects

Atrial natriuretic peptide, vasoactive intestinal peptide, beta-endorphin and cortisol are humoral variables characterized by a 24-h periodicity. We evaluated the circadian rhythm of these peptides and hormones in healthy subjects who were young (between 20-25 years) or elderly (between 65-75 years). All were on controlled diets. Blood samples were collected six times during a 24-h period (at 06.00, 08.00, 12.00, 18.00, 20.00 and 24.00 h) beginning 8-h after start of recumbency. The time-related data were analysed by the Cosinor method in order to validate the circadian rhythm and to quantify rhythmometric parameters which included the midline estimate of rhythm (mesor). In contrast to the young subjects, Cosinor analysis failed to reveal a significant circadian rhythm in elderly subjects, for plasma cortisol. In elderly subjects oscillation (mesor) of atrial nutriuretic peptide was higher, while that of vasoactive intestinal peptide and beta-endorphins was lower. The results suggest changes in the physiological secretion of these three peptides in healthy elderly subjects.

[Circadian rhythm of arterial blood pressure and heart rate in patients with heart transplantation: a longitudinal study before and after transplantation]

This investigation is designed to study the circadian rhythm (CR) of blood pressure (BP) and heart rate (HR) in heart transplanted patients (HTP). The research was performed on 10 heart failure patients (HFP), IV NYHA class, who underwent heart transplantation (HT) because of a primary congestive cardiomyopathy. The 24-h BP and HR monitorings were performed by means of a non-invasive method in pre-operative stage, over the 4 post-operative days, 6 and 12 months after surgery. ANOVA and Cosinor method validated the occurrence of a statistically significant CR in HFP. Over the 4 days after HT, the Serial Section Analysis did not show a 24-h periodicity of BP and HR: 6 months after HT, the BP and HR CR was not validated as well. One year after HT, the BP and HR CR was statistically detected. A significant difference between HTP and the clinically healthy subjects was validated only for the mean value of HR. In our opinion, the consolidation of the BP and HR CR 1 year after HT might be regarded as a clinical feature of a reacquired matching of cardiac function with vascular activity.

Vasoactive intestinal peptide fluctuates in human blood with a circadian rhythm

The vasoactive intestinal peptide (VIP) may be radioimmunoassayed in systemic venous blood. The plasma concentrations of VIP were investigated in human blood according to a chronobiological design. The study documented a circadian rhythmicity in time-qualified concentrations of VIP. Accordingly, VIP may be ascribed to biological variables characterized by periodicity in their physiological attributes. The rhythmic physiology of VIP is, however, highly disturbed in its tonic and phasic properties during senescence.

[The disappearance of the circadian rhythm of the heart rate in heart transplantation in the presence of acute rejection]

The present study is aimed to investigate the circadian rhythm (CR) of heart rate (HR) in acute rejecting and non-rejecting heart transplanted patients (HTP). The purpose is to provide evidence that an impairment in the HR CR may have a role in predicting episodes of acute rejection in HTP. The study was carried out on 32 Holter monitorings of 13 patients: 9 Holter monitorings were carried out during an episode of acute rejection documented by endomyocardial biopsy. Time data series were analyzed by Cosinor method in order to validate the occurrence of HR CR. The Cosinor analysis found a highly statistically significant HR CR in non-rejecting HTP. The occurrence of the HR CR was not statistically validated in acute rejecting HTP. These findings suggest that the lack of a periodic variability in the 24-hour HR pattern may be useful to diagnose acute heart rejection.

[Cutaneo-cerebral bullous syndrome in patients with type II diabetes mellitus]

This study deals with a case of non-insulin dependent diabetes mellitus complicated by a diffuse giant vesicular dermatosis in combination with an irreversible coma caused by encephalopathy with hypodense areas on the CT scan. The coma, unlike the known diabetic comas and unrelated to infectious, toxic and cerebrovascular noxae, was interpreted as due to bullous lesions of the brain comparable to the cutaneous vesicles.

Chronobiological evidence for an uncoupling of the Na,K-ATPase to aldosterone in normal renin hypertension

The Na,K-ATPase activity of erythrocyte membranes is markedly increased in normal-renin essential hypertensives. A temporal shift of the chronobiology of the erythrocyte-membrane-bound Na,K-ATPase in these patients is described. The disorder causes a loss of synchronism between the circadian rhythms of aldosterone and Na,K-ATPase. Such uncoupling phenomenon may explain the inversion of the day/night sodium excretion ratio and other disturbances of sodium metabolism found in essential hypertensives.

The circadian rhythm of serum angiotensin-converting enzyme is disrupted in ascitic liver cirrhosis

An increase in morning fasting levels of plasma (P) renin activity (RA), aldosterone (A) and serum (S) angiotensin-converting enzyme (ACE) activity has been demonstrated in ascitic cirrhotic patients (ACP). Since both PRA and PA change biorhythmically in their time structure, the relationship of SACE activity with the components of the renin-angiotensin-aldosterone system (RAAS) was investigated in clinically healthy subjects (CHS) and ACP. Time-qualified data were chronobiologically analysed by means of the cosinor procedure to resolve and quantify the circadian rhythm (CR). The 24-hour mean levels of PRA, PA and SACE activity were found to be elevated in ACP as compared to CHS. The temporal variability of these analytes was found to be of periodic type along the 24-hour span in CHS, but not in ACP. The well-organized cyclicity in CHS is of relevant interest. PRA and PA cycles were found to phase in a clear antiparallelism with the SACE activity CR. The phase opposition may be, speculatively, related to the physiologic nature of ACE, whose activity is devoted to generate angiotensin II. The disappearance of SACE activity CR in ACP is in accordance with the abolition of PRA and PA cyclicity and suggests a role of liver in regulating the periodic time function of the RAAS and related components.

The gerontological decline of the renin-aldosterone system: a chronobiological approach extended to essential hypertension

The circadian (about 24-hr) oscillating function of the renin-angiotensin-aldosterone system (RAAS) was investigated as a function of age in clinically healthy participants and in essential hypertensive patients. A peculiar age-related decline in the RAAS circadian mesor (rhythm-adjusted mean) and amplitude (variability from mesor) was found in the essential hypertensive patients. This finding suggests a nonphysiologic evolution in the tonic (24-hr mean level) as well as phasic (oscillating amplitude) circadian activity of the RAAS with increasing age. A relative hyperreninemic aldosteronism characterized the aged essential hypertensive patients.

Increased serum aldosterone in diabetic pregnancy

Serum levels of aldosterone and cortisol were measured by radioimmunoassay in 15 patients with gestational diabetes, in 18 patients with Type 1 (insulin-dependent) diabetes, in 36 pregnant control women and in 10 non-pregnant control women. All subjects, on habitual sodium and potassium intake, were sampled in a supine position at 09.00 hours. Pregnant women were examined twice, during gestational week 32-34 and at delivery. Serum levels of aldosterone and cortisol were also measured in the umbilical cord blood of newborn babies of these diabetic and non-diabetic mothers. Serum levels of aldosterone in both gestational and Type 1 pregnant diabetic women were found to be consistently above the reference values of non-diabetic pregnant women. Abnormal serum levels of aldosterone were also observed in newborn infants of diabetic mothers. In contrast, serum levels of cortisol were not increased.

Effects of a mild and prolonged restriction in sodium or food intake on the circadian rhythm of aldosterone and related variables

The effect of a mild reduction in dietary sodium intake (-30 mEq/24 hr) and body weight (-2 kg/2 months) on circadian rhythms of urinary aldosterone (UA), sodium (UNa), potassium (UK), creatinine (UC) and volume (UV) have been investigated in nine clinically healthy subjects. The mild reduction in dietary sodium is associated with: (1) a decrease in the 24-hr excretion rate of UNa, UK and UV, and an increased mesor of UA and UC; (2) a lowered extent of the circadian variation for UNa, UK, UV and a greater amplitude for UA and UC (3) a later crest in the temporal phase for UK, UA, UC, an earlier phasic wave for UNa. The mild reduction in calorie intake resulting in a body weight loss is associated with a more pronounced decrease in the 24-hr excretion rate of UNa and UK, and in the extent of circadian fluctuation for UNa. Peculiar events are: (1) the decreased 24-hr excretion rate for UA, and the increased mesor for UV; (2) the extent variability increased for UV, decreased for UC. Such effect may have a practical resonance for heuristic physiology since the role of dietary sodium and food intake has been better clarified. Dietary sodium and food can be regarded as 'chronomodulatory agents' for the adrenal cortex since their adrenotropic influence is extended to the tonic as well as phasic secretion of aldosterone.

[Disorders of renin secretion in arterial hypertension]

The present work is devoted to investigate the meaning of disorders in renin secretion in primary and secondary hypertension and report the results of bayesan analysis applied to a group of 125 hypertensives who underwent selective renal angiography and polydistrictual renal vein samplings for the determination of plasma renin activity for diagnostic and therapeutic purposes. Data obtained from statistical analysis allow specifications on the prevalence of disorders, rates of false positives and false negatives, predictive value, diagnostic value, sensitivity and specificity. The weighted data are useful to validate the reliability of the renin renal vein measurements which are used in clinical practice for identifying the potentially surgically curable forms of arterial hypertension.

Temporal correlation of some endocrine circadian rhythms in elderly subjects

The aim of this chronobiological study was to investigate temporal correlations in the circadian patterns of 6 hormones, namely somatotrophic hormone (STH), prolactin (PRL), cortisol (F), aldosterone (ALD), insulin (IRI) and C-peptide (CP), assayed in systemic blood serum drawn at 07:00, 10:00, 13:00, 16:00, 19:00 and 22:00 h from an antecubital vein in 19 young subjects (aged 20-29 yr, comprising 10 males and 9 females; and 20 elderly subjects (aged 70-81 yr, comprising 10 males and 10 females). All subjects were sampled on a normal dietary sodium intake (120-140 mEq/24h) while following a social routine of diurnal activity (07:00-23:00) and nocturnal rest (23:00-07:00). Time-qualified data were analyzed by lead-lag correlation and by cosinor analysis. According to the lead-lag correlation findings, it would appear that the correlation which exists between several time-qualified series in young subjects is no longer present in elderly subjects. The circadian rhythms which were found to have lost their temporal correlations with advancing age were those between STH and IRI, STH and ALD, PRL and IRI, PRL and CP, and ALD and CP. It should be noted that the correlation between hormonal rhythms breaks down mainly on account of a peculiar age-related change in the magnitude of the circadian fluctuation. This chronological decline in amplitude led to the conclusion that the senescence of endocrine rhythmic functions is a biological phenomenon characterized by altered circadian variability.

Study of the diurnal variation of human lymphocyte subsets

The diurnal variation of peripheral white cells and in particular of different lymphocyte subsets has been investigated in 11 normal subjects. Monoclonal antibodies (Mab) phenotyping total T lymphocytes (UCHT1), cytotoxic/suppressor (UCHT4), helper T cells (Leu 3a), B lymphocytes (231) and K/NK cells (H25) have been used. In addition to the traditional parametric statistics, the chronobiological approach of cosinor was adopted in order to inferentially obtain the waveform covering the 24-hr period. Cosinor analysis validated the existence of a significant rhythm for leucocytes (p = 0.04, lymphocytes (p = 0.03), and Leu 3a positive cells (p = 0.04). The best fitting period was equal to 28 hr. No circadian rhythm was documented for lymphocyte subsets positive for Mab UCHT4, 231, H25, by testing the variability with a frequency ranging from 1 cycle every 12hr to 1 cycle every 28 hr. By the non-inferential analysis of temporal curves, a significant peak of Leu 3a positive cells at 20.00 hr (p less than 0.001) was observed. The acrophase has been recorded by cosinor analysis at 20.36 hr. We conclude that the circadian variability of Leu 3a positive cell profile must be taken into account when the helper/suppressor ratio is calculated. The time-dependence of this lymphocyte subpopulation suggests that when therapy with corticosteroids is considered in autoimmunity, it should be planned by keeping the peak of Leu 3a positive cells as a marker time.

May a lymphocytic infiltration have a pathogenic role in an aldosterone-producing adrenal tumor?

A 38-year-old woman is described to have a primary hyperaldosteronism due to an aldosteronoma with foci of lymphocytic infiltration. The finding suggests: a concomitant lymphoid adrenalitis; or, an immunological attack to neoplastic cells. The hypothesis is that there may be a relationship in the association. The lymphocytic infiltrates could have a pathogenic role in the development of the aldosterone-producing adrenocortical neoplasm by interrupting some inhibitory mechanism(s) of the cells that secrete aldosterone.

Circadian rhythms of plasma renin activity and aldosterone: changes related to age, sex, recumbency and sodium restriction. Chronobiologic specification for reference values

Plasma renin activity (PRA) and aldosterone (PA) levels are characterized by a circadian rhythmicity (CR). The present study revealed that this rhythmicity is influenced by several factors including posture, sodium intake and age. Time-qualified PRA and PA reference intervals can reduce the incidence of false positives and false negatives in a diagnostic work-up. The circadian rhythmicity of PRA and PA have been quantified in relation to posture, sodium intake and age. The cosinor procedure has been applied to quantify the properties of the circadian rhythmicity under these conditions. Chronograms and circadian parameters can be used to optimize the use of PRA and PA measurements in clinical practice. The chronobiological specification of reference values for PRA and PA is of valuable importance since the assessment of PRA and PA circadian rhythmicity has a diagnostic interest for a certain type of clinical disorder. It should be noted that several studies have described circannual variations for renin and aldosterone. The next step in the optimation of laboratory time-qualified reference values is the assessment of changes induced by the deterministic factors on a circannual domain.