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Biomedical subjects

E Petrescu

Publications and source records attributed to E Petrescu.

At least 19 recordsLinked to original sources
PubMed1992

Chronobiology of pituitary-thyroid functions.

One hundred ninety four children, 11 +/- 1.5 years of age and 166 elderly men and women, 77 +/- 8 years of age were studied over one or (in the case of some of the elderly subjects) over several (up to 4) 24-hours spans. All subjects were diurnally active and rested at night and followed their regular three meal pattern. The subjects were studied in subgroups of 20-25 during all four seasons of the year. During each study, blood was collected at 4 hour intervals over one 24-hour span (6 samples). Circadian and circannual variations were found and described by cosinor analysis in the children as well as in the elderly subjects. The children with endemic goiter (134) as compared to those without endemic goiter (60) showed a slight circadian phase advance in plasma total and free T3, a lower circadian amplitude of total T4 concentrations and the absence of a detectable circadian rhythm in free T4. The children with goiter showed a phase delay in serum TBG. There was no difference between the children with and without goiter in the circadian MESOR of any thyroid parameter or of TSH. The children with endemic goiter in the region of Dimboviţa, Romania, are in clinical and biochemically euthyroid condition with some slight poral abnormalities of thyroid function. Seasonal variations in children and elderly patients showed the highest values of TSH during summer and fall, while the highest values in the plasma concentrations of thyroid hormones were found during the cold season of the years. Thyroglobulin in the children showed a circadian rhythm but no seasonal variation.

Aged↗
PubMed1991

Circadian, weekly, and seasonal variations in cardiac mortality, blood pressure, and catecholamine excretion.

Time of occurrence of cardiac death due to arrhythmia, heart failure, or acute myocardial infarction was recorded in 86 elderly subjects, belonging to a group in whom circadian and circannual rhythms in blood pressure and urinary catecholamine excretion had been studied previously. All patients were retired, with no work responsibilities, and lived--closely-supervised in a home for the aged--on a routine that provided little differences between weekdays and weekends. Cardiac mortality showed a circadian variation, with a peak in the early morning hours, coinciding with the circadian peak in systolic and diastolic blood pressures. A weekly (circaseptan) variation in cardiac mortality was found, with the greatest number of patients dying on Mondays and the least on Thursdays. There were seasonal differences in cardiac mortality, with a peak in July and a broader peak during the cold season (December to February). The former coincides with the circannual peak in diastolic blood pressure, but is unrelated to the seasonal variation in norepinephrine excretion. Circadian, circaseptan, and circannual variations in cardiac mortality appear to be the expression of time-dependent, transient risk states for catastrophic cardiac events, which may lend themselves to preventive treatment.

Aged↗
PubMed1987

Peculiarities of the endocrine time structure in noninsulin-dependent adult-onset (type II) diabetes mellitus.

Twenty noninsulin-dependent elderly diabetic patients, ten of whom were treated by oral hypoglycemic agents and ten of whom were regulated by diet alone, and 20 clinically healthy subjects matched for age, sex, height, and weight were examined with six blood and six urine samples at 4-hr intervals over a 24-hr span. Plasma ACTH, cortisol, aldosterone, and dehydroepiandrosterone-sulfate (DHEA-S) were determined by radioimmunoassay (RIA); epinephrine, norepinephrine, and dopamine in urine were determined by high-pressure liquid chromatography (HPLC); and magnesium in urine was determined colorimetrically on a DuPont ACA. There were a number of changes in some of these functions in type II diabetic patients with and without oral hypoglycemic agents that appear to be of interest. The circadian mean in plasma ACTH concentration in diabetic patients with and without oral hypoglycemic agents is significantly higher than in matched nondiabetic controls. The plasma aldosterone concentration is similar in type II diabetics treated by diet only and in matched controls but is statistically significantly elevated in patients on oral hypoglycemic agents. Correspondingly, the urinary excretion of sodium in type II diabetic patients on oral hypoglycemic agents is lower than in matched controls. The plasma cortisol concentration is unchanged in type II diabetic patients treated by diet alone but shows a slight increase in patients on oral hypoglycemic agents. The circadian means of plasma DHEA-S concentration is slightly higher in diabetic patients with and without oral hypoglycemic agents than in matched controls. This elevation, however, does not quite reach the 95% level of statistical significance. Urinary norepinephrine excretion in type II diabetic patients is similar to that in matched controls. The urinary epinephrine excretion in diabetics with and without oral hypoglycemic agents, however, was lower than in controls, and the urinary excretion of dopamine was higher in the diabetics. The urinary magnesium excretion in type II diabetic patients was lower than in matched controls.

Adrenal Cortex Hormones↗
PubMed1987

Circadian and circannual variations of thyroid function in children 11 +/- 1.5 years of age with and without endemic goiter.

A group of 194 children 11 +/- 1.5 years of age from Tirgoviste, Romania, an endemic goiter area, were studied over a 24-hr span (six blood samples at 4-hr intervals) during all four seasons. One hundred thirty-four of the children had some clinical evidence of endemic goiter, and 60 had none. Total and free T3 and T4, reverse T3, thyroglobulin, thyroxin-binding globulin (TBG; three seasons only), and TSH were studied. The circadian rhythms were analyzed by cosinor and the circannual variations by ANOVA. Children with and without endemic goiter showed circadian rhythms in all functions studied except free T4 for which no statistically significant rhythm was detected in the children with goiter. There were differences in the acrophase of total T3, free T3, and TBG, with phase advance in the children with goiter in total T3 and free T3 and a phase delay in TBG. Mesor and amplitude showed no differences except in total T4 for which the amplitude in the children with goiter was statistically significantly lower than in the children without goiter. Children with and without endemic goiter showed seasonal variations in total T4 and free T4 as well as total T3, free T3, and reverse T3, with the highest values in the fall; in thyroxin-binding globulin the highest values were in the winter; and in TSH the highest values were in the summer. There was no significant seasonal variation in thyroglobulin. There was no difference in the circannual variation between children with and without endemic goiter.

Child↗
PubMed1987

Circannual variations in blood pressure, urinary catecholamine excretion, plasma aldosterone, and serum sodium, potassium, calcium, and magnesium in children 11 +/- 1.5 years of age.

A total of 194 clinically healthy children 11 +/- 1.5 years of age were studied during different seasons. Systolic and diastolic blood pressure were determined by auscultatory endpoints, and blood and urine were collected at 4-hr intervals over a 24-hr span. Urinary norepinephrine, epinephrine, and dopamine were determined by HPLC, plasma aldosterone by RIA, serum sodium and potassium by ion-specific electrode, and calcium and magnesium by colorimetry. The circadian means showed statistically significant circannual variations in all variables except epinephrine. The highest circadian means of systolic and diastolic blood pressure and of urinary norepinephrine occurred during winter; the highest values of plasma aldosterone, serum potassium, and urinary dopamine were found in fall, those of serum calcium and magnesium during the summer, and that of serum sodium in spring. Circannual rhythms characterize functions related to blood pressure regulation in children. The circannual elevation of blood pressure (within the usual range) and of norepinephrine were both found to occur in winter. This time relation may have a functional significance, although a causal relationship is not proven by the temporal coincidence of two rhythms.

Aldosterone↗
PubMed1987

Chronobiology of catecholamine excretion in different age groups.

Urine was collected at 4-hr intervals over a 24-hr span in 87 boys and 106 girls 11 +/- 1.5 years of age and over one or several 24-hr spans in 62 elderly men and in 85 elderly women 77 +/- 8 years of age. Epinephrine, norepinephrine, and dopamine were determined by HPLC. The data were analyzed by cosinor and by one-, two-, and three-way ANOVA. Children and elderly subjects showed circadian rhythms of urine volume and of the excretion of norepinephrine, epinephrine, and dopamine. While the urine volume was higher in the elderly subjects than in the children, norepinephrine, epinephrine, and dopamine excretion in the girls and epinephrine in the boys showed a statistically significantly higher mesor than in the elderly subjects of the same sex. There was a sex difference, with lower values in all variables in the girls and women compared to their male counterparts; the circadian amplitudes of norepinephrine, epinephrine, and dopamine in the girls and of epinephrine in the boys were higher than the circadian amplitudes in the elderly subjects. The circadian timing in urinary excretion between the elderly subjects and the children was different, with a consistent phase delay; the acrophase of the circadian rhythm in the elderly subjects moved in the night hours. In contrast, there was no age difference in the acrophase of norepinephrine and epinephrine excretion or in dopamine in the females. In the males, the circadian rhythm in dopamine excretion in the elderly subjects did not quite reach statistical significance at the P less than 0.05 level. Circannual variations with high values in winter and low values in spring and summer were found in norepinephrine excretion in boys, girls, and elderly women, but not in elderly men. In neither age group was there a statistically significant seasonal variation in epinephrine. Only in girls was a statistically significant circannual rhythm in dopamine excretion found, with highest dopamine values in the fall and lowest values in winter and spring.

Age Factors↗
PubMed1987

Circannual rhythms of laboratory measurements in serum of elderly subjects.

A total of 160 elderly subjects 77 +/- 8 years of age were studied in 201 24-hr profiles consisting of six blood samples collected at 4-hr intervals. The sampling sessions were spread over all four seasons. The circadian means were analyzed (one-way ANOVA) for the presence of circannual variations. Statistically significant circannual variations were found in the serum concentrations of albumin, bilirubin, calcium, chloride, CPK, globulin (calculated), glucose, LDH, potassium, sodium, triglycerides, uric acid, and total protein. The data presented indicate that many chemical constituents commonly measured in human serum and urine show seasonal variations in elderly subjects, some of which are large enough to present potential diagnostic problems. Others may not pose diagnostic problems in today's practice of laboratory medicine, but indicate seasonal changes in metabolic functions or, if endogenous in nature, circannual rhythms that may be of physiologic and pathobiologic importance. There is a need to quantify certain of these rhythms as a predictable portion of variability in laboratory values and presumably as an indicator of human health.

Aged↗
PubMed1987

Endocrine factors of blood pressure regulation in different age groups.

Systolic and diastolic blood pressures were measured and blood and urine were collected at 4-hr intervals over a 24-hr span in 194 diurnally active children 11 +/- 1.5 years of age and in 278 elderly subjects 77 +/- 8 years of age. Plasma aldosterone and cortisol were determined by radioimmunoassay, serum calcium and magnesium on a Dupont ACA, and urinary epinephrine and norepinephrine by high-pressure liquid chromatography. In the children, there was a slight but statistically significant positive correlation between the circadian means in systolic blood pressure and norepinephrine excretion and serum calcium, and between diastolic blood pressure and norepinephrine excretion and serum calcium and magnesium. In the elderly subjects, there was a positive correlation between the circadian mean in diastolic blood pressure and aldosterone. In contrast to the findings in the children, however, the elderly subjects showed a negative correlation between the circadian means in norepinephrine excretion and in systolic and diastolic blood pressures. These investigations indicate differences in the regulation of the blood pressure within the "usual range" between children and elderly subjects. This has to be kept in mind in the study of essential hypertension, a syndrome that may be caused by different mechanisms in different age groups.

Age Factors↗
PubMed1984

Circadian endocrine time structure in humans above 80 years of age.

The circadian rhythms in blood hormone concentrations of 17 pituitary, adrenal, pancreatic, testicular, and thyroid hormones were determined in 9 women and 5 men 81 to 91 years of age. Six samples over a 24-hr span were studied for each hormone. Even with the small sample available, 9 of the 17 hormones determined showed a statistically significant circadian rhythm as a group phenomenon (prolactin, estradiol, 17-hydroxyprogesterone, insulin, C-peptide, thyroid stimulating hormone, aldosterone, cortisol, dehydroepiandrosterone sulfate). No rhythm detection by population mean cosinor analysis at the .05 level was obtained in this relatively small group of subjects for adrenocorticotropic hormone, follicle stimulating hormone, growth hormone, luteinizing hormone, triiodothyronine, thyroxine, progesterone (determined in women only) and testosterone (determined in men only).

Adrenocorticotropic Hormone↗
PubMedDate not supplied

Circadian rhythm parameters of endocrine functions in elderly subjects during the seventh to the ninth decade of life.

The circadian rhythm of 17 endocrine parameters (ACTH, aldosterone, cortisol, C-peptide, DHEA-S, FSH, growth hormone, insulin, LH, 17-OH progesterone, prolactin, testosterone, total T3, total T4 and TSH and estradiol and progesterone in women only) were studied in 63 clinically apparently healthy men (124 profiles) and 86 women (154 profiles) during the 7th to 9th decade of life. The subjects lived under very uniform conditions in a home for the aged with their daily schedule standardized by institutional routine with rest at night on the average from 21:30 to 06:30 local time and 3 daily meals at 08:30, 13:00 and 18:30. Blood was drawn over a 24-h span at 4-h intervals. Circadian periodicity was ascertained and the rhythm parameters quantified by cosinor analysis. In clinically healthy elderly subjects, circadian periodicity persisted in most parameters studied well into the 9th decade of life. The timing of the circadian rhythm was comparable between subjects in their 7th decade and 9th decade of life with the exception of cortisol and DHEA-S, which showed a phase advance with advancing age. A decrease in circadian amplitude is limited during this part of the human life span to only a few of the functions investigated and with the exception of prolactin in the women, a decrease in amplitude did accompany a decrease in MESOR.

17-alpha-Hydroxyprogesterone↗
PubMedDate not supplied

Circadian and seasonal variations in iodine excretion in children with and without endemic goiter.

The urinary iodine excretion was measured in 193 children 11 +/- 1.5 years of age living in the endemic goiter area of Dîmboviţa, Romania. One hundred and thirty four of the children showed some degree of endemic goiter, 59 showed none. All children followed a diurnal activity pattern with rest during the night. They received their usual iodine supplement of 1 gm potassium iodide once a week during the school year (which included the time of all measurements made). Urine was collected in six 4-hour samples over a 24-hour span. The examinations were conducted during the months of March, June, September and December. Iodine was determined by an automated ceric ion arsenic acid method using a Technicon Autoanalyzer. Circadian and seasonal variations of urine volume and iodine excretion were statistically verified by the cosinor technique and the seasonal variations also by one way analysis of variance using the circadian means as input. A comparable circadian rhythm of iodine excretion was found in the children with and without endemic goiter, with an acrophase during the evening (20:16 with a 95% C.I., from 19:32 to 21:04). The circadian rhythm in iodine excretion has to be taken into account whenever an estimate of the 24-hour excretion is attempted from a sample covering less than the entire 24-hour span. There was a statistically significant seasonal variation of the 24-hour iodine excretion in the boys with and without endemic goiter and in the group as a whole. The 24-hour iodine excretion during March was 102 +/- 6 mcg, during June 81 +/- 4 mcg, during September 79 +/- 3 mcg and during December 102 +/- 7 mcg. The average 24-hour iodine excretion pooled over all seasons was 91 +/- 3 mcg/24 hrs in the children with and 91 +/- 5 mcg/24 hrs in the children without endemic goiter. During March and December the iodine excretion indicates an iodine intake not usually associated with a high prevalence of endemic goiter. However, during the months of June and September (and presumably even more during the months of July and August when during summer vacation no iodine supplementation was given in school) the 24-hour iodine excretion indicates some degree of iodine deficiency. The seasonal variation in urinary iodine excretion thus points to a time when increased iodine prophylaxis may be of value.

Child↗
PubMedDate not supplied

Circadian and circannual variations of FSH, LH, testosterone, dehydroepiandrosterone-sulfate (DHEA-S) and 17-hydroxy progesterone (17 OH-Prog) in elderly men and women.

A group of 63 men and 86 women 77 +/- 8 years of age institutionalized at the Berceni Clinical Hospital, Bucharest, Romania, on a diurnally active living schedule with rest at night, eating 3 comparable but not identical meals a day, were investigated over a 2-year span in 278 profiles extending over a 24-hour span each and distributed over all our seasons. On each day of sampling six samples of blood were collected at 4-hour intervals beginning at 0800 of the first day of the study to 0400 of the next. Plasma testosterone, dehydroepiandrosteronesulfate (DHEA-S), 17-hydroxyprogesterone (17-OH Prog), FSH and LH concentrations were determined by radioimmunoassay. Statistically significant circadian rhythms were detected and quantified by population mean cosinor for the men and women of the entire group and for the age groups of 51 to 70 (I), 71 to 80 (II) and above 80 years of age (III) separately. Circannual rhythms of the circadian means were sought and evaluated by one way analysis of variance. Statistically highly significant circadian rhythms were found in plasma testosterone, 17-OH Prog and DHEA-S, concentrations in men and women of all three age groups with a phase advance of over 2 hours in DHEA-S with advancing age. Circannual cycles were found for plasma testosterone concentration and for DHEA-S in men and women, with a likely phase difference between men and women in testosterone. In LH a circadian rhythm was found in the women and in FSH in men only and a circannual variation in LH only in men.

17-alpha-Hydroxyprogesterone↗