PubMed Health⌕ Search

Biomedical subjects

A H Vagnucci

Publications and source records attributed to A H Vagnucci.

At least 19 recordsLinked to original sources
PubMed1994

Suckling-induced attenuation of plasma cortisol concentrations in postpartum lactating women.

The effect of suckling on serum cortisol concentrations was assessed in postpartum lactating women studied during serial breast feeding sessions 1-24 weeks postpartum. The mean +/- SD serum cortisol concentration at 15 min after the start of nursing, 9.8 +/- 3.89 micrograms/dl, was significantly lower, P = 0.001, than prior to the start of nursing, 13.2 +/- 5.92 micrograms/dl. The decline in the serum cortisol concentrations in the breast feeding women was not due entirely to the normal metabolism of the hormone or the normal circadian variation in cortisol secretion. These studies complement and expand upon a recent report [3] of a significant decrease in plasma adrenocorticotrophic hormone in breast feeding women studied one week postpartum. The neuroendocrine mechanisms responsible for this effect in women have yet to be defined.

Adrenocorticotropic Hormone↗
PubMed1993

Circadian rhythm of lymphocytes and their glucocorticoid receptors in HIV-infected homosexual men.

Glucocorticoids (Gc) are known to modulate protein synthesis by immune cells through binding to a specific receptor (GcR). We outlined the circadian rhythm of plasma cortisol, ACTH, of the peripheral blood mononuclear cells (PBMC isolated by Ficoll-Hypaque technique), and of their subsets CD4, CD8 in 14 asymptomatic HIV+ homosexual men and in nine controls. We also estimated the GcR of the PBMC at 0700 and at 2300 hours, near the peak and nadir of the cortisol rhythm. In the HIV+ subjects, the PBMC circadian rhythm is abolished, an observation that confirms previous reports; in more than half of these patients, the GcR dissociation constant is larger than that of the controls. The circadian rhythms of plasma cortisol and ACTH levels do not differ from those of the controls. These changes may impair the function of the hypothalamic pituitary-adrenal axis in the HIV-infected subject.

Adrenocorticotropic Hormone↗
PubMed1991

Classification of plasma cortisol patterns in normal subjects and in Cushing's syndrome.

The 24-h pattern of half-hourly sampled plasma cortisol in normal human subjects shows a 24-h (circadian) period, which may be variably distorted in patients who suffer from autonomous hypercortisolism (Cushing's syndrome). We have developed a pattern recognition system for computer classification of cortisol time series into the normal class and subclasses of Cushing's syndrome with different etiology ("pituitary" designating pituitary tumor, "adrenal" designating adrenal tumor, and "ectopic" designating tumor elsewhere). Discriminatory features were extracted from Fourier analysis and Karhunen-Loeve expansion coefficients of cortisol time series. Decision functions were trained by the LMSE algorithm and tested by the jack-knife test procedure on a data-base of 90 normal and patient patterns. The classification accuracy for normal, "pituitary," "adrenal," and "ectopic" classes was 100, 98.1, 98.3, and 100%, respectively. Hence this pattern recognition system may be useful as an aid in the differential diagnosis of Cushing's syndrome.

Algorithms↗
PubMed1989

Bilateral massive adrenal hemorrhage: early recognition and treatment.

PURPOSE: To develop a clinical perspective on bilateral massive adrenal hemorrhage and an algorithm for its diagnosis and treatment. DATA IDENTIFICATION: Case reports were identified through a computer search using MEDLIN (1976 to 1987), and from bibliographies in review articles (up to 1978). STUDY SELECTION: Twelve reports published since 1978 were found. DATA EXTRACTION: Data from 20 recently reported cases and 5 cases from personal records were compared with data from 142 previously reported, autopsy-proven cases summarized in a 1978 review article. RESULTS OF DATA ANALYSIS: Thromboembolic disease, coagulopathy, and the postoperative state were the three major risk factors. Except for abdominal pain and remittent fever, clinical features were not helpful in diagnosis. A fall in hemoglobin, and progressive biochemical hypoadrenalism were important clues. Diagnosis was confirmed by computed tomography and an absent cortisol response to intravenous corticotropin. Long-term follow-up showed complete atrophy and functional failure of the adrenal gland. CONCLUSIONS: Death from bilateral massive adrenal hemorrhage can be prevented by pre-emptive steroid therapy in high-risk patients who have certain clinical and laboratory features.

Adolescent↗
PubMed1986

Hemostatic defects in response to aspirin challenge in hypothyroidism.

A patient with hypothyroidism had ingested aspirin and bled profusely following dental extraction. The only abnormalities noted on coagulation survey were a prolonged aspirin bleeding time and reduced retention of platelets on glass beads. Based on this index case, an additional 12 hypothyroid patients, on no medications, were evaluated for a mild bleeding disorder, including studies with aspirin challenge. The results indicate that thrombin-induced platelet serotonin release, following aspirin ingestion, was subnormal in most hypothyroid patients. However, only hypothyroid individuals with TSH levels of greater than 60 microU/ml have an increased hemostatic sensitivity to aspirin, as measured by the bleeding time test. These findings did not appear to result from decreased synthesis of the factor VIII-von Willebrand factor complex. As this drug is commonly ingested, the effects of aspirin on bleeding may explain the easy bruising and menorrhagia that occur in hypothyroid individuals.

Aspirin↗
PubMed1986

Cushing's disease with intermittent hypercortisolism.

In a patient with proved pituitary-dependent Cushing's syndrome (Cushing's disease), 24-hour urinary excretion of free cortisol fluctuated between normal (69 percent of the time, often in the low range and for several days in sequence) and high values. Increased urinary free cortisol excretion occurred unpredictably within the context of a persistent, progressive clinical picture. This case stands in contrast with previous reports of urinary steroid levels varying in a periodic infradiem pattern. Even with normal baseline cortisol indexes, control of the hypothalamic-pituitary axis (as indicated by the suppression test and by the circadian cortisol pattern in plasma) remained abnormal. This patient emphasizes the fact that abnormal control regulation, more than cortisol hypersecretion, is at times indicative of Cushing's disease. Hence, sensitive accurate screening requires not only urinary free cortisol measurement (the usefulness of which may be improved by assay of more than one, possibly nonsequential, 24-hour urine sample), but also dexamethasone suppression testing and late-evening plasma cortisol determination, even if baseline indexes are within the range of normal.

17-Ketosteroids↗
PubMed1986

Enhanced sodium appetite in rats with lesions centered on nucleus medianus.

Recent experiments have demonstrated that rats with lesions of the ventral portion of nucleus medianus (vNM) frequently exhibit a chronic and robust hyperdipsia, which occurs only at night. This study indicates that the same brain damage may produce a nocturnal appetite for sodium that is similarly pronounced and persistent. Of 68 rats with vNM lesions, 33 were observed to drink at least 15 ml of 0.51 M NaCl solution per day, and 11 of them consumed more than 30 ml daily. The basis for this impressive consumption of saline is uncertain; the brain-damaged rats had normal sodium concentrations, renin activities, and aldosterone levels in plasma during basal maintenance conditions, and they conserved sodium in urine when maintained on a sodium-deficient diet. Nevertheless, the present results indicate that vNM and/or local fibers of passage may play an important role in the control of sodium appetite, as it does in the control of thirst.

Aldosterone↗
PubMed1980

TSAN: a package for time series analysis.

Many biomedical data are in the form of time series. Analyses of these data include: (1) search for any biorhythm; (2) test of homogeneity of several time series; (3) assessment of stationarity; (4) test of normality of the time series histogram; (5) evaluation of dependence between data points. In this paper we present a subroutine package called TSAN. It is developed to accomplish these tasks. Computational methods, as well as flowcharts, for these subroutines are described. Two sample runs are demonstrated.

Computers↗
PubMed1979

Analysis of circadian periodicity of plasma cortisol in normal man and in Cushing's syndrome.

In normal subjects, adjusted to a circadian environment, half-hourly plasma cortisol levels over a 24-h span (time series, TS) outline a circadian sinusoidal pattern that may be masked by superimposed short-lived oscillations. The periodogram objectively defines the features (amplitude, phase) of this pattern in individual TS and, more efficiently, in the average and concatenation of homogeneous TS. Concatenation is a procedure by which homogeneous short TS are attached one after the other. Homogeneity is inferred by variance analysis and by a new measure, h, with statistical significance, derived from the spectrum of the concatenated TS. Through concatenation, autocovariance for periodicity identification becomes possible. The TS from three groups of volunteers are highly homogeneous and have a predominant, statistically significant amplitude with peak time near 1100 h. The patterns from patients with Cushing's disease differ markedly in their means and periodic features; by the above criteria, we identify a subgroup with significant h measure and 24-h amplitude. This analysis provides a tool for investigation of the circadian clock in man.

Adolescent↗
PubMed1979

Renin and aldosterone secretions during hypovolemia in rats: relation to NaCl intake.

Plasma renin activities (PRA) and aldosterone concentrations increased in parallel over a wide range of plasma volume deficits produced in unanesthetized rats by extravascular administration of polyethylene glycol (PEG) solution. When PEG-treated rats were given water to drink, their intakes were proportional to PRA; when given water and 0.5 M NaCl, PRA and the steroid concentrations diminished concurrently in association with sodium consumption. Aldosterone concentrations and NaCl intakes were markedly enhanced after PEG treatment in rats maintained on a sodium-deficient diet for 4 days. On the other hand, a clear relation between PRA and water intake, and between circulating aldosterone levels and sodium intake, was not suggested by other experiments in this series. For example, bilateral nephrectomy abolished the rise in PRA during hypovolemia yet rats drank water normally. Moreover, aldosterone concentrations were substantially elevated by PEG treatment in the nephrectomized rats yet sodium appetite was abolished. These and other findings suggest that neither angiotensin nor aldosterone plays a prominent role in stimulating water and saline intakes during hypovolemia.

Aldosterone↗
PubMed1978

The multiple factors affecting plasma renin activity in essential hypertension.

Seventy-nine patients with essential hypertension were evaluated for peripheral renin activity in response to injection of 60 mg of furosemide and to upright posture. Age and supine diastolic blood pressure were found to be significant determinants of responsiveness, with contributions from sex and race. Patients with impaired responsiveness were predominantly older and female, while the group of hyperresponders was younger, male, and had significantly lower supine diastolic pressures. Aldosterone responses in relation to changes in peripheral renin activity were found to be nearly random with both furosemide and with posture. Thus, patients could be subdivided into renin subgroups, but not into parallel aldosterone subgroups. Data on four patients with primary hyperaldosteronism were discussed for comparison.

Adolescent↗
PubMed1975

Relationships of the renin-angiotensin-aldosterone system and sodium balance to blood pressure regulation in chronic renal failure of polycystic kidney disease.

In 5 patients with polycystic kidney disease and creatinine clearances ranging from 4 to 40 ml/min, relationships between changes in blood pressure, sodium balance, body fluid compartments, plasma renin activity (PRA), urinary aldosterone excretion, and plasma aldosterone concentrations were studied during periods of low, medium, and high sodium intake. Total body water (TBW), total exchangeable body sodium (TEBS), and extracellular volume (ECV) were measured by isotope dilution techniques, plasma volume with Evan's blue dye, and PRA and aldosterone by radioimmunoassay. Low sodium intake reduced kidney function, blood pressure, and serum sodium, while PRA reached its highest levels. Subsequent increases in sodium intake improved kidney function and increased blood pressure. Plasma volume increased slightly and ECV markedly, while PRA dropped to 15 percent of the value noted after the low sodium intake. TBW and TEBS showed inconsistent changes. Aldosterone changes correlated closely with PRA. Blood pressure showed a negative correlation with PRA, but a positive one with body weight and cumulative sodium balance, and with plasma and extracellular volumes.it is suggested that whereas renin and aldosterone are involved in the maintenance of circulatory homeostasis during sodium loss, sodium retention causes an increase in blood pressure by concomitant changes in body fluids.

Adult↗