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Biomedical subjects

C Letizia

Publications and source records attributed to C Letizia.

At least 145 records · Page 8Linked to original sources
PubMed1984

Toward a chronophysiology of circulating aldosterone.

The physiology of aldosterone secretion has been prominently investigated by homeostatic studies on the levels of the steroid in plasma and/or urine. Aldosterone secretion is, however, arranged in a rhythmic fashion along the 24-hr cycle. The dynamics of aldosterone should thus be reanalyzed chronobiologically in order to gain further insight into the physiology of the hormone. Such a revisitation has been performed in the present study on four groups of clinically healthy volunteers categorized according to sex and age. Aldosterone has been assayed in the plasma of systemic venous blood six times a day (0600, 0800, 1200, 1800, 2000, 0000) in different conditions of physical activity and sodium intake. Time-qualified data have been analyzed by the single-cosinor method and then summarized by the population-mean cosinor procedure to quantify the circadian rhythms in their properties (mesor, amplitude, acrophase). Differences in rhythmometric parameters have been tested by a multivariate analysis for vectorial units. (Hotelling's T2 test). Cosinor analysis indicates that the dynamics of circulating aldosterone substantially changes in relation to posture. The habit of having a routine of diurnal activity leads the circadian rhythm of aldosterone to delay its acrophase from morning to afternoon. The postural shift of acrophase is essentially accompanied by an elevation in the 24-hr mean level. The restriction of salt intake is associated with an increase in mesor; the temporal localization of the circadian crest shows, however, a very high stability. Sex is not characterized by significant differences in the 24-hr patterns of aldosterone in the sense that young males and females show substantially identical time-qualified curves and circadian parameters. Increasing age until the seventh decade in life is responsible for changes mainly in 24-hr mean levels with a slight modification in amplitude. Such a chronophysiology for circulating aldosterone related to the motor-rest schedule, sodium intake, sex, and age, is of interest not only to heuristic but also to practical approaches in clinical medicine.

Adolescent↗
PubMed1984

[Parametric methods applied to the standardization of gestational reference intervals for blood renin activity, aldosterone and cortisol using the transversal and longitudinal approach].

This investigation is devoted to define monthly-qualified gestational reference intervals for plasma renin, aldosterone and cortisol as derived by transverse or longitudinal approaches. Reference intervals refer to 95% confidence interval, 90% tolerance interval, the 95% predictive interval, in addition to the mean plus or minus the standard error and standard deviation. By applying both methodological approaches it has been found that plasma renin and aldosterone exhibit a progressive gestational increase. By contrast, cortisol shows an initial increase and thereafter stays on the same values. Statistical analysis revealed the transversally--and longitudinally--derived reference intervals to be not statistically different. Because of such a similarity, laboratory medicine can interchangeably use both kinds of reference intervals for estimating the normality of plasma renin, aldosterone and cortisol values in a single case of pregnancy. This interchangeability of values leads to simplify the methodology for measuring plasma renin and aldosterone in pregnancy since it is not necessary to standardize the gestational nomograms for renin-sodium and/or aldosterone-sodium relationship. This is a real way to reduce the costs and to optimize the compliance in the monitoring of pregnancy.

Adolescent↗
PubMedDate not supplied

Type B1 thymoma in multiple endocrine neoplasia type 1 (MEN-1) syndrome.

AIMS AND BACKGROUND: Multiple endocrine neoplasia (MEN) syndromes include a group of disorders characterized by the neoplastic transformation of two or more endocrine tissues. In type 1 syndrome (MEN-1), pituitary, parathyroid and pancreatic islet tumors are most frequently represented. Thymic neoplasms are also rarely associated, and thymectomy during subtotal or total parathyroidectomy should always be considered. STUDY DESIGN: The authors describe a rare case of a 22-year-old male who presented a type B1 thymoma without myasthenia gravis associated to hyperparathyroidism, corticoadrenal adenoma and three neuroendocrine pancreatic lesions (somatostatinoma, glucagonoma and insulinoma).

Adult↗
PubMedDate not supplied

Significant changes of peripheral perfusion and plasma adrenomedullin levels in N-acetylcysteine long term treatment of patients with sclerodermic Raynauds phenomenon.

The unclear pathogenesis of scleroderma vascular lesions makes treatment of Raynaud's phenomenon (RP) in Systemic Sclerosis (SSc) patients very difficult and a new effective treatment is requested. Recently, a powerful antioxidant agent, the N-acetylcysteine (NAC) has been shown to decrease the frequency and severity of RP in SSc patients. Subsequently, using functional infrared imaging, we showed that a single 1-hour NAC infusion in these patients caused a significant increase of skin temperature. The aim of this study was to demonstrate the efficacy of long term therapy with NAC in an open clinical trial evaluating clinical, instrumental and laboratory parameters. Patients started the treatment receiving for two years, from October to May, intravenous NAC infusions of 15 mg/kg per hour each, for 5 consecutive hours, every two weeks. Before and after each infusion, patients underwent both Laser Doppler perfusion Imaging (LDPI) for the evaluation of the digital perfusion and a blood test to ascertain the plasma adrenomedullin (AM) levels. The NAC infusion increased global hands perfusion and induced a significant decreasing of plasma AM concentrations. Side effects were negligible, easy to control and reversible. Reduction of frequency and severity of RP attacks was recorded. In conclusion, NAC seems to act as an effective vasodilatator in the treatment of RP secondary to SSc and, in addition, it induced significant changes in plasma levels of AM, a potent vasodilator endothelial-derived peptide.

Acetylcysteine↗
PubMedDate not supplied

[Adrenomedullin. A new peptide involved in the regulation of the cardiovascular system].

Adrenomedullin was originally discovered in human pheochromocytoma but is now known to be widely distributed in various organs. Adrenomedullin is a potent vasodilatator peptide that exerts major effects on cardiovascular function. Plasma adrenomedullin concentration is increased in patients with cardiovascular disease such as hypertension, congestive heart failure, myocardial infarction, renal failure and other diseases. The present review summarizes the recent advances on adrenomedullin research and demonstrates that adrenomedullin is one of the important vasoactive peptides involved in the physiology and pathophysiology of cardiovascular system.

Adrenal Gland Diseases↗
PubMedDate not supplied

[Assessment of conventional approaches in adrenalectomy].

The choice of operative approach represents one of the main problems of adrenal gland surgery, nowadays the minimally invasive techniques (laparoscopic adrenalectomy) in selected cases may be an important alternative to conventional approaches. Retrospective analysis was performed on 140 patients with adrenal gland tumors from 1980-1997; there were 95 women and 45 men: The tumors were resected through flank extraperitoneal approach (35 patients), transabdominal (91), thoraco-abdominal (14). Operating time, perioperative blood loss, postoperative course were evaluated. The authors conclude that in functioning and non-functioning adenomas, in pheochromocytoma, smaller than 6 cm., with precise pre-operative unilateral localization, flank extraperitoneal approach may be sufficient, in patients with Cushing disease resistant to pituitary surgery or irradiation, in patients with familiar history or bilateral pheochromocytoma, in patients with suspected malignant disease, a thorough surgical exploration of the abdominal cavity is recommended.

Adolescent↗
PubMedDate not supplied

[Therapeutic approach in Riedel thyroiditis].

Riedel's invasive fibrous thyroiditis is a rare disorder of unknown origin with progressive extension and invasion of adjacent structures. Clinically it is impossible to distinguish between Riedel's/thyroiditis and other diseases as undifferentiated carcinoma, Hashimoto's disease etc... The patients often have dyspnea, dysphagia, paralysis of the vocal cord; fine needle puncture-aspiration and biopsy themselves may be insufficient, Surgical treatment depends on the stage of the disease, when both lobes are involved generous wedge resection of the isthmus may be the treatment of choice to relieve tracheal compression; in earlier stages radical operation are considered. Corticosteroid treatment in Riedel's thyroiditis, as multifocal disease has been successfully used. Other drugs with antifibrosing actions have also utilised in small groups of patients with encouraging results.

Aged↗
PubMedDate not supplied

[Malignant pheochromocytoma. Personal experience, review of the literature].

Pheochromocytoma is a catecholamine-producing tumor of the sympathetic nervous system which in 4-14% of the cases may be malignant. The differentiation between benign and malignant phoechromocytomas is very difficult, the presence of metastatic lesions and gross invasion into surrounding tissues are the lonely accettable parameters to confirm malignancy. Since the patients with malignant pheochromocytomas have a very poor survival rate, care must be taken for an early detections and a careful follow up. Three cases of malignant pheochromocytoma are reported. In one of these cases the tumor was a functioning mass; the other two cases presented by a hemorrhagic complication. A careful review of the pertinent literature allows to outline the correct approach to this rare pathology as for the diagnosis and the treatment, also including the actual criteria to establish its malignancy.

Adrenal Gland Neoplasms↗
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

[Serum activity of angiotensin-converting enzyme and osteocalcin levels in hyperthyroidism].

This study was carried out in order to investigate serum changes of osteocalcin (BGP) and angiotensin converting enzyme (SACE) activity in a group of patients with hyperthyroidism. We studied 20 hyperthyroid patients (F 14, M 6; age mean 37.5 +/- 16.8 years) and 13 control subjects (F 11, M 2; age mean 40.3 +/- 7.5 years). In both patients and controls we measured: FT3, FT4, T3, T4, TSH, BGP, SACE. Finally, in patients with hyperthyroidism a TRH test and functional investigations were also performed. We observed that mean SACE levels were significantly increased in hyperthyroid patients (32.06 +/- 10.3 nmol/ml/min) in respect to control subjects (14.66 +/- 3.88 nmol/ml/min) (p = 2.02 E-6). Similarly serum BGP levels were significantly increased in hyperthyroid patients (5.94 +/- 2.55 ng/ml) than in control subjects (2.89 +/- 1.58 ng/ml) (p = 5.66 E-4). There was a significant linear correlation between SACE and T4 levels (r = 0.48; p < 0.05), between serum BGP and T4 (r = 0.50; p < 0.02) and furthermore between SACE and BGP (r = 0.57; p < 0.01). In conclusion both serum BGP and SACE levels are increased in patients with hyperthyroidism and are directly correlated between than and with indexes of thyroid function; therefore, they may be regarded as peripheral indexes of hyperthyroidism.

Adult↗
PubMedDate not supplied

[A case of primitive amyloid goiter].

Amyloid goiter is a rare pathology due to massive amyloid infiltration of thyroid tissue, which cause diffuse or localized enlargement of the gland. It can be totally asymptomatic or cause only non-specific symptoms (compression of adjacent structures, tracheal deviation). Thyroid disfunction (hypothyroidism or hyperthyroidism) is rare. It is important to differentiate primitive amyloid goiter from other kinds of amyloid infiltration of the thyroid, such as in systemic amyloidosis. The correct diagnosis can be difficult because of the common presence of amyloid in thyroid neoplasms, such as medullary thyroid carcinoma (MTC). The Authors present a case of primitive amyloid goiter, that needed immunohistochemical analysis for a correct diagnosis, and a review of the concerning literature.

Aged↗
PubMedDate not supplied

[Tubercular Addison's disease with high titers of microsomal thyroid antibodies and reduced thyroid function reserve].

This case reports deals with a male patient, white, aged 51, bricklayer, tobacco smoker. At 43 years old a tubercular epididimite was surgically treated with orchiectomy. Recently, the reports marked weakness, weight loss, headache, vertigo, hypotension. On admittance to the hospital, hyperpigmentation was also present. Previous therapy (cortisone acetate 40 mg/die), was suspended, clinical investigations showed impaired adrenal and thyroidal functions; antimicrosomal antibodies were also present. Therefore therapy with cortisone acetate (25 mg x 2/die, 9-alpha-fluorohydrocortisone 0.1 mg/die and L-thyroxine 100 mcg/die) was instituted with marked improvement of the patient's conditions. This case reports highlights the importance of proceeding with complete investigations on the system, even when dealing with a tubercular Addison's disease.

Addison Disease↗