P. Cugini

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. Students t test for unpaired data and Binghams 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.

Serum angiotensin-converting enzyme activity in pre-eclamptic pregnancy: evidence for a relative hypermesorACEemia.

The circadian rhythm of serum angiotensin-converting enzyme (ACE) activity was investigated in pregnant women with normal and pre-eclamptic gestation. The chronobiological approach was able to document the occurrence of a circadian rhythm for serum ACE activity in normal pregnancy. Such a rhythm is characterized by a decreased mesor and amplitude and a shifted crest. The circadian rhythm for serum ACE activity was not detectable in pre-eclamptic pregnancy. Such an abrogation is accompanied by a negligible decrease of mesor suggesting the occurrence of a relative hyperACEemia. This disorder could play a role in pregnancy-induced hypertension.

A Chronobiological Approach to Circulating Levels of Renin, Angiotensin-Converting Enzyme, Aldosterone, ACTH, and Cortisol in Addison's Disease

This study deals with a chronobiological approach to the circadian rhythm of the renin-angiotensin-aldosterone system (RAAS) and the ACTH-cortisol axis (ACA) in patients with Addisons disease (PAD). The aim is to explore the mechanism(s) for which the circadian rhythmicity of the RAAS and ACA takes place. The study has shown that both the RAAS and ACA are devoid of a circadian rhythm in PAD. The lack of rhythmicity for renin and ACTH provides indirect evidence that their rhythmic secretion is in some way related to the circadian oscillation of aldosterone and cortisol. This implies a new concept: a positive feedback may be included among the mechanisms which chronoregulate the RAAS and ACA.

Adrenocortical Nodular Dysplasia Causing Cushing's Syndrome: Clinical Differences Between Pediatric and Adult Cases

The recent report /I/ by Matoth and coworkers of a rare case of infantile adrenocortical dysplasia prompted us to review the literature with the aim of clarifying the nature of this disease in the pediatric age group. Statistical criteria were adopted to detect possible differences between the pediatric and non-pediatric descriptions. We found a large enough number of case reports to permit statistical analysis of clinical and laboratory parameters in this entity.

Altered Circadian Rhythmicity for Angiotensin Converting Enzyme Activity in Migraine

Abstract:This investigation is devoted to the exploration of the 24 h patterns of the serum angiotensin converting enzyme (ACE) activity in clinically healthy subjects and normotensive migraine patients. A comparison was made with cortisol circadian rhythmicity. Time data series were analyzed by means of chronobiology procedures. The biostatistical approach has documented that the enzymatic activity of serum ACE changes with a circadian periodicity in clinically healthy subjects. The crest of this fluctuation is temporally located in the afternoon and shows an approximately 12 h delay when compared with cortisol circadian rhythm. Furthermore, the chronobiologic approach revealed that the enzymatic activity of serum ACE lacks a circadian biorthythmicity in migraine. By contrast, the morning crest of the circadian rhythmicity of cortisol cycle is preserved. The biochemical implication of this phenomenon in migraine patients is not readily evident. There may possibly be a relatively increased catabolism of enkephalins, which in its turn may contribute to the dysnociception of migraine. The altered time structure for the serum ACE circadian activity is, however, a biochemical aspect characterizing migraine syndrome.