Twenty-four-hour, weekly and annual patterns in serious falls of non-institutionalized independent Spanish seniors

OBJECTIVE

The study aimed to explore clock hour, day-of-week, and month-of-year patterns of serious falls experienced by non-institutionalized Spanish seniors (age ≥65 years) in relation to associated conventional intrinsic and extrinsic factors.

PATIENTS AND METHODS

Intake emergency department records from January 1 to December 31, 2013 of a tertiary hospital of southern Spain were abstracted for particulars of falls, including the time of occurrence, experienced specifically by non-institutionalized seniors. Chi-squares and Single and Multiple-Component Cosinor (time series) Analyses were applied to determine the statistical significance of observed 24-hour, 7-day, and annual variation.

RESULTS

Falls were ~2.5-fold more numerous in older women than older men and ~7-fold more frequent between 12:00 and 14:00 hours than ~02:00 hours, respectively, the time spans corresponding to the absolute peak and trough of the 24-hour pattern in falls. The midday/early afternoon peak primarily represented incidents of women ≥75 years of age that occurred inside the home while walking, standing, or moving on stairs. A late evening less prominent excess of mostly inside-the-home incidents of women ≥75 years of age, largely due to fragility, slipping, stumbling, or tripping, was additionally detected. Cosinor Analysis substantiates statistical significance of the 24-hour patterning of falls of men and women (both p<0.001). Day-of-week differences, with prominent Thursday peak and Sunday minimum, were additionally detected, but only for falls of women occurring outside the home (Cosinor Analysis: p=0.007). Day-of-week discrepancy in female/male sex ratio (SR) of fallers was demonstrated, arising from day-of-week disparity in the SR of inside-the-home incidents, with ~4.5-fold more elderly women than elderly men falling Thursday than any other day of the week (p=0.005). Non-statistically significant month-of-year difference in falls, lowest in autumn and highest (~60% more) in winter, was observed and explained by prominent seasonal difference in incidents by elderly women.

CONCLUSIONS

Serious falls of non-institutionalized independent seniors are characterized according to intrinsic and extrinsic factors by prominent 24-hour and 7-day patterning. These findings complement the understanding of the epidemiology of falls of the elderly and further inform fall prevention programs.

Creatinine clearance and blood pressure: a 34-year circadian study

BACKGROUND AND OBJECTIVE

The first circadian study of the 361st Medical Laboratory, USAR, was conducted in May 1969 during the Annual Military Training at Brook Army Hospital, Fort Sam Houston, Texas. The study was approved by the Surgeon General, 5th US Army, and was designed to establish a circadian database for 63 medically relevant variables of 13 young members of the Unit. The subsequent studies, all in the month of May, in 1979, 1988, 1993,1998, and 2003, followed the same protocol and were conducted at Edward Hines Jr., Veterans Administration Hospital, after approval by Human Studies Subcommittees. Since a reduction in Creatinine Clearance (CrCl) to the level of 60 ml/min/1.73m2 signals the onset of kidney malfunction and since a concurrent increase in blood pressure (BP) >140/90 mm Hg, contributes greatly to an unfavorable cardiovascular prognosis, it seemed prudent to examine possible changes in these and in other relevant variables in a group of young Army men, which may have developed over a 34 year period of time.

MATERIAL AND METHODS

Thirteen US Army male volunteers (23-27y of age) served as subjects in the 1969 study. A majority of these men, two additional Army men and two non-military subjects, participated in subsequent studies: 1979 (7,2,1), 1988 (8,2,1), 1993 (5,4,1), 1998 (7,2,2), 2003 (7,2,1). In each study, subjects were admitted to a hospital ward, were given medical examination including a 12-lead electrocardiogram and followed the same Protocol. Lights "OUT" at 22:30h and "ON" at 06:30h. The meals, hospital 2400-calorie diets, were served at 17:30, 07:30 and at 13:30h. Vital signs were measured immediately after each 3h urine collections, around the clock, and bloods were collected every 3h. Blood, plasma, serum, saliva and urines were analyzed for numerous analytes including creatinine, using automated laboratory systems. Kidney functions were assessed using the measured and estimated glomerular filtration rates.

RESULTS

Over the 34y study span, 16 men provided sixty-one 24h profiles for CrCl-related variables (urine volume, creatinine, and serum creatinine) and fifty-eight profiles for BP. Using all normalized data, a significant circadian rhythm was found for each of these variables. Significant circadian variations in SBP, DBP, serum and urine creatinine, and urine volume, were evident with peak levels, on average, occurring in the evening hours.

CONCLUSIONS

In healthy subjects, age was associated with an increase in SBP and urine volume and with a decrease in urine creatinine. In diabetic subjects, aging was associated with increases in both blood pressure and Creatinine Clearance. It is interesting to note that for the 3 subjects who at a later date developed diabetes, the CrCl levels were higher than the 5 age-matched controls during each study year, over the entire 34y observation span, including the period prior to diagnosis. Clin Ter 2008; 159(6):409-417.

Circadian rhythms of basic fibroblast growth factor (bFGF), epidermal growth factor (EGF), insulin-like growth factor-1 (IGF-1), insulin-like growth factor binding protein-3 (IGFBP-3), cortisol, and melatonin in women with breast cancer

BACKGROUND

Circadian rhythms in plasma concentrations of many hormones and cytokines determine their effects on target cells.

METHODS

Circadian variations were studied in cortisol, melatonin, cytokines (basic fibroblast growth factor IbFGF], EGF, insulin-like growth factor-1 [IGF-1]), and a cytokine receptor (insulin-like growth factor binding protein-3 [IGFBP-3]) in the plasma of 28 patients with metastatic breast cancer. All patients followed a diurnal activity pattern. Blood was drawn at 3h intervals during waking hours and once during the night, at 03:00. The plasma levels obtained by enzyme-linked immunoassay (ELISA) or radioimmunoassay (RIA) were evaluated by population mean cosinor (using local midnight as the phase reference) and by one-way analysis of variance (ANOVA).

RESULTS

Cortisol and melatonin showed a high-amplitude circadian rhythm and a superimposed 12h frequency. bFGF showed a circadian rhythm with an acrophase around 13:00 with a peak-to-trough interval (double amplitude) of 18.2% and a superimposed 12h frequency. EGF showed a circadian rhythm with an acrophase around 14:20, a peak-to-trough interval of 25.8%, and a superimposed 12h frequency. IGF-1 showed a high value in the morning, which is statistically different (t test) from the low value at 10:00, but a regular circadian or ultradian rhythm was not recognizable as a group phenomenon. IGFBP-3 showed a low-amplitude (peak-to-trough difference 8.4%) circadian rhythm with the acrophase around 11:00 and low values during the night.

CONCLUSIONS

(1) Circadian periodicity is maintained in hospitalized patients with metastatic breast cancer. (2) Ultradian (12h) variations were superimposed on the circadian rhythms of the hormones and several of the cytokines measured. (3) Studies of hormones and cytokines in cancer patients have to take their biologic rhythms into consideration. (4) The circadian periodicity of tumor growth stimulating or restraining factors raises questions about circadian and/or ultradian variations in the pathophysiology of breast cancer.

Melatonin levels in women with fibromyalgia and chronic fatigue syndrome

OBJECTIVE

Fibromyalgia (FM) and chronic fatigue syndrome (CFS) are stress associated disorders mainly affecting women. FM is characterized primarily by widespread musculoskeletal pain, and CFS by profound debilitating fatigue, but there is considerable overlap of clinical symptoms between these 2 syndromes. Neuroendocrine abnormalities have been noted in both FM and CFS and desynchronization of circadian systems has been postulated in their etiology. The pineal hormone melatonin is involved in synchronizing circadian systems and the use of exogenous melatonin has become widespread in patients with FM and CFS.

METHODS

We examined the characteristics and relationship of melatonin and cortisol levels in premenopausal women with FM (n = 9) or CFS (n = 8), compared to age and menstrual cycle phase matched controls. Blood was collected from an indwelling intravenous catheter every 10 min over 24 h, and plasma melatonin and cortisol were determined by radioimmunoassay at 60 and 10 min intervals, respectively.

RESULTS

Night time (23:00-06:50) plasma melatonin levels were significantly higher in FM patients compared to controls (p<0.05), but there was no significant difference in melatonin levels between CFS patients and controls. No differences in the timing of cortisol and melatonin secretory patterns and no internal desynchronization of the 2 rhythms were found in either patient group, compared to controls.

CONCLUSION

Raised plasma melatonin concentrations have been documented in several other conditions that are associated with dysregulation of neuroendocrine axes. Increased melatonin levels may represent a marker of increased susceptibility to stress induced hypothalamic disruptions. These data indicate that there is no rationale for melatonin replacement therapy in patients with FM and CFS.

Time-dependent variations of the skin barrier function in humans: transepidermal water loss, stratum corneum hydration, skin surface pH, and skin temperature

Although circadian rhythms have been described for many human functions, there are minimal data on circadian rhythms related to skin physiology. This study investigated the circadian rhythmicity of skin variables related to skin barrier function in humans. We measured transepidermal water loss, stratum corneum moisture, skin surface pH, and skin temperature in 16 healthy volunteers (nine men and seven women, aged 23-53 y). Subjects were sampled every 2 h in two sessions over a 24 h span. Twelve samples were obtained for each variable in the following sites: forehead, forearm, upper back, and shin. We used cosinor analysis and ANOVA to validate observed differences. Time-dependent rhythms were detected in most skin variables except in stratum corneum hydration. We found a statistically significant circadian rhythmicity characterized by cosinor analysis in transepidermal water loss, skin surface pH, and skin temperature on the forearm, forehead, and shin. Peak-trough differences occurred in all locations. The values of the same variables measured at different sites correlated positively, whereas the values of the different variables did not. These results suggest that skin permeability is higher in the evening and night than in the morning. These data may be clinically relevant in several aspects applied to skin physiology and topical drug application.

Circannual variation of cell proliferation in lymphoid organs and bone marrow of BDF1 male mice on three lighting regimens

BDF1 male mice, which had been raised for several generations on a lighting regimen of LD 12:12, were studied. Experiments were conducted over 24 h spans during winter, spring, summer, and fall. For 3-4 weeks prior to each study, one-third of the animals were kept on a lighting regimen of 8 h of light alternating with 16 h of darkness (LD 8:16), one-third was kept on a regimen of LD 12:12, and one-third was kept on a regimen of LD 16:8. Subgroups of mice on all three lighting regimens were killed at 4 h intervals over a 24 h span. At 20 minutes prior to sacrifice, the animals received 5 microCi of 3H-thymidine/0.2 ml/20 gm body weight intraperitoneally. The thymidine uptake in DNA (DPM[3H]/microgram DNA) was studied as an index of cell proliferation in the thymus, inguinal lymph node, spleen, femur, and a segment of the lumbar vertebral column. A circannual variation of 3H-thymidine uptake in DNA was found in all organs irrespective of the lighting regimen under which the animals were kept. The timing of the circannual variation, however, varied among the organs. In the thymus, the lowest thymidine uptake occurred during summer, with higher thymidine uptake during the other three seasons. In the inguinal lymph node, the peak in thymidine uptake was in the spring, with lower values during the other three seasons, the lowest during summer. In the spleen, the highest thymidine uptake occurred in the mice on all three lighting regimens during fall, with lower uptake during winter, spring, and summer. In the bone marrow of both the femur and the vertebral column, the thymidine uptake was high in winter and fall and low in spring and summer. Serum corticosterone measurements were available in winter, spring, and fall, and they showed statistically significant lower values in winter and fall than in spring. The conclusion was drawn that circannual rhythms of 3H-thymidine uptake in the DNA of the thymus, spleen, lymph nodes, and bone marrow are found in mice reared for generations under a LD 12:12 lighting regimen and persist if the animals are kept under a regimen of LD 8:16 or LD 16:8 for 3-4 weeks prior to sacrifice.

Stimulation of the secretion of dehydroepiandrosterone by melatonin in mouse adrenals in vitro

Adrenals of young adult male mice kept on a LD 12:12 lighting regimen for three weeks prior to study and harvested at four different circadian stages were incubated for 2 hours with 0.4 IU synthetic ACTH in 2 ml Krebs-Ringer buffer (KR), or with 50, 150, and 450 microM of melatonin in KR containing 0.4 IU ACTH. The addition of melatonin to ACTH leads to a dose dependent stimulation of production and/or secretion of DHEA into the incubation medium irrespective of the circadian stage of harvesting of the adrenals. This relationship is of interest in view of the simultaneous decrease of dehydroepiandrosterone and melatonin in the course of aging, and the effects of these compounds upon aging related changes.

The pattern of hormonal circadian time structure (acrophase) as an assessor of breast-cancer risk

Through many hormones are secreted in a pulsatile manner, their secretion pattern can be superimposed by a 24-hour sinusoidal curve. The sinusoidal curve is then characterized by the estimated peak clock time location (acrophase), the adjusted mean (mesor) and the amplitude. When the distribution of the acrophases of 12 hormones was compared among women with regard to their age and to the level of risk of developing breast cancer, statistically significant differences were revealed between distribution patterns of acrophases of women with high (n = 12 and 45 circadian profiles) or low (n = 12 and 41 circadian profiles) risk of developing breast cancer. However, when the amplitude/mesor ratios of the corresponding hormonal rhythms were analyzed, significant differences occurred between age groups rather than between risk levels. These observations suggest that the endocrine time structure between individual women can be used as an assessor of breast-cancer risk.

Prevalence of genetic versus environmental factors in human female temporal organization: preliminary analysis

Genetic diversity among ethnic groups is studied by comparing the genetic fingerprint of the examined groups. This index is constructed by aggregating the differential frequencies of various marker characteristics. Recent advances in the study of human biological rhythms may provide new indexes that will complement the genetic profile of a population. One of the rhythm parameters that is especially useful for this purpose is the acrophase (peak time location). The aim of the present study is to construct a rhythm profile based on acrophase distribution for various human groups and to estimate the contribution of genetic and environmental factors to that profile. The rhythm profiles were constructed by comparing the acrophases of 11 plasma hormones in women from three different ethnic-geographic populations (North Americans, Romanians, and Japanese) with reference to three age groups (adolescence-early postpuberty, young adulthood, and postmenopause). Genetic distances of these ethnic groups were determined by 14 genetic markers. Cluster and principal coordinates analyses were used to define the variation of the two parameters (genetic distances and acrophase dispersion). The analyses show that North Americans and Romanians are closer to each other with regard to both parameters and far apart from the Japanese. However, there was a difference between the variation presented by the first eigenvalue of the genetic profiles (94.5%) and that of the first eigenvalue of the acrophase pattern (69.1%), which means reduction in the variability (increased similarity) among the three ethnic groups according to the acrophase profiles.(ABSTRACT TRUNCATED AT 250 WORDS)

Human circadian time structure in subjects of different gender and age

Most human variables exhibit rhythms with an about 24 hour (circadian) period. Each rhythm can be characterized by its acrophase (calculated peak time of the cosine curve best fitting to the data), its amplitude and rhythm adjusted mean (MESOR). The sequential array of the rhythms' acrophases represents the temporal order of the human time structure. In the present work we used circadian rhythms of 24 chemical and 15 hormonal variables extracted from published studies which were done in a defined area of southeastern Europe (Romania). All studies had a comparable experimental design and were analyzed biochemically and statistically in the same laboratory. The acrophases of these rhythms obtained from both genders of different age groups (from the 2nd to the 9th decade of age) were subjected to multiple correlation test, cluster and principal coordinates analyses. The results show that the temporal order is affected both by gender and age, and evaluate the degree of the effect, offer a "chronbiologic fingerprint" for the examined groups and assist in dissecting rhythm variability among populations.

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.

Circadian variations in blood coagulation parameters, alpha-antitrypsin antigen and platelet aggregation and retention in clinically healthy subjects

Ten clinically healthy subjects (5 men and 5 women), 31 +/- 11 yrs of age, were studied at six timepoints (0800, 1200, 1600, 2000, 0000, 0400) distributed over a 1-week span. Circadian rhythms in platelet aggregation in response to adenosine diphosphate (ADP) and adrenalin (A), platelet adhesiveness measured as retention in a glass bead column, prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time (TT), fibrinogen, Factor VIII activity and alpha-1-antitrypsin antigen showed circadian rhythms. The plasma concentrations of plasminogen, alpha-2-macroglobulin, and antithrombin III (AT III) antigen, Factor V and fibrinogen degradation products showed no circadian rhythm by ANOVA or cosinor analysis. The phase relations of the rhythms of different coagulation parameters are of interest in the physiology and pathobiology of the coagulation-fibrinolytic system. The extent of the circadian rhythm (range of change) described is not of a magnitude to lead to diagnostic problems in the clinical laboratory. The timing of these rhythms, however, may determine transient risk states for thromboembolic phenomena, including myocardial infarction and stroke. Several but not all coagulation parameters suggest a transient state of hypercoagulability during the morning hours. The recognition of these rhythmic, and thus in the time of the occurrence predictable temporary risk states for thromboembolic phenomena, may lead to timed treatment and/or effective prevention.

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.

Circadian rhythms in urinary trace element and electrolyte excretion in children with and without endemic goiter

Six boys and six girls 11 +/- 1.5 years of age living in the endemic goiter area of Tîrgovişte, Romania were studied. Three of the children of each sex did have a palpable endemic goiter, three did not. The children followed a diurnal activity pattern synchronized by their school routine and ate their usual three meal diet. Urine was collected at 4-hour intervals over a 24 hour span (six samples). Urinary volume, pH, total (T) solids, protein, glucose, phosphorus, uric acid, urea nitrogen, creatinine, total and nondialyzable (ND) sodium and potassium were determined by conventional methods and the total and nondialyzable (ND) portion of urinary calcium, magnesium, and zinc and the ND portion of aluminum, copper, boron, lead and silicon were determined by an inductively coupled plasma (ICP) system.

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.

Circadian hematologic time structure in the elderly

Twenty-three clinically healthy, diurnally active elderly subjects, 71 +/- 5 years of age were studied over a 24-hr span (six samples). Complete blood counts and differential counts were done (Ortho ELT-8, Wright stained smears). The circadian rhythm parameters of the hematologic variables in the elderly subjects were compared with reference values obtained from a larger group of clinically healthy young adult and adult subjects studied independently. The data were analyzed by cosinor and the Bingham test. Circadian rhythms in the number of circulating formed elements in the peripheral blood persist in the aged. In comparison with the young adult, the elderly subjects show differences in the timing (phase advance) of the circadian rhythms in circulating neutrophil leukocytes and lymphocytes, a decrease in the circadian amplitude of circulating platelets, a decrease in circadian rhythm adjusted mean (mesor) in the red cell count, and in the neutrophil band forms.

Chronobiology of serum iron concentration in subjects of different ages at different geographic locations

The circadian rhythm in serum iron concentration was studied in 61 elderly men (74 +/- 6 years of age) and 93 women (78 +/- 8 years of age) in Bucharest, Romania, in 81 clinically healthy boys and 103 girls (11 +/- 1.5 years of age) in Tîrgovişte, Romania, in 4 elderly men and 19 women (71 +/- 5 years of age) and in 75 young-adult men (24 +/- 11 years of age) and 52 women (24 +/- 9 years of age) in St. Paul, Minnesota, USA. Six samples were obtained from each subject around a 24-hour span. The sampling sessions in the elderly subjects in Romania and in the children extended over all four seasons. A circadian rhythm statistically verified by Cosinor analysis was evident in all groups in both locations. A statistically significant sex difference with lower circadian mean (mesor) and a lower amplitude in the women was found in the Romanian elderly subjects. The children in Romania showed no sex difference in any circadian rhythm parameters. The young adult subjects in Minnesota showed a significantly higher mesor and a phase delay in the men as compared with the women. The elderly subjects of both sexes at both geographic locations had a lower circadian mesor than the young adults and the children. In the Romanian elderly subjects also the circadian amplitude was lower, which was not the case in the Minnesotans. While the acrophase in the elderly subjects and in the children in Romania was comparable (0928 and 0932 local time resp.), the young adults in Minnesota showed in comparison to the Romanians a phase delay (1132 local time) and the elderly in Minnesota showed a phase advance (0732 local time) in comparison to all other groups. The latter finding will have to be confirmed by more extensive studies. In the elderly subjects in Romania the circadian rhythm in serum iron concentration was in phase with the circadian rhythms in total serum bilirubin and alkaline phosphatase but showed significant phase differences from the circadian rhythms in serum albumin, urea nitrogen (BUN), gammaglutamyl transferase (Gamma-GT), serum globulins, glucose, insulin and total serum proteins. The elderly subjects in Romania showed a statistically significant circadian phase delay in summer as compared to fall but showed no seasonal variation of the mesor. The children showed a circadian phase advance in fall as compared to the other seasons and a seasonal variation of their mesor with higher values in spring and summer as compared with winter and fall.(ABSTRACT TRUNCATED AT 400 WORDS)

Circadian rhythm of beta-endorphin in the plasma of clinically healthy subjects and in patients with adrenocortical disorders

Immunoreactive beta-endorphin was determined in the plasma of 37 elderly subjects (73 +/- 7 years of age), in 3 young or young adult subjects without adrenal disease, in 4 women with clinical adrenogenital syndrome, in 1 man with Cushing's disease. Immunoreactive beta-endorphin in plasma was measured by radioimmunoassay in six samples of each subject collected at 4-hour intervals over a 24-hour span. The observation of a circadian rhythm in circulating immunoreactive beta-endorphin with highest values during the late night and early morning hours is extended to elderly subjects in the 8th decade. The beta-endorphin plasma concentrations in the few clinically healthy young adult subjects studied fell within the same range. The circadian variation of the group of elderly subjects was used as reference in the clinical evaluation of plasma beta-endorphin concentrations in patients with pituitary-adrenocortical disorders. The need for circadian rhythm qualified reference values is shown by the observation of the circadian variations of circulating immunoreactive beta-endorphins in the patients with adrenogenital syndrome and Cushing's disease in whom abnormalities in the concentration of circulating beta-endorphin were found at certain circadian stages but not at others.

Circannual rhythms of systolic and diastolic blood pressure in relation to plasma aldosterone and urinary norepinephrine in elderly subjects and in children

Sixty six elderly men and 87 elderly women 77 +/- 8 (S.D.) years of age were studied in 285 profiles consisting of measurements of systolic and diastolic blood pressure obtained at 4 hour intervals during the waking hours of the subjects for 2 or 7 days and (among others) plasma aldosterone and urinary norepinephrine determinations collected in six samples at 4 hour intervals during one 24-hour span. The profiles were spread through all four seasons. The circadian means were calculated for each profile by the single cosinor method and the circannual variations were analyzed by the Bingham test and analysis of variance. A circannual rhythm of the systolic and the diastolic blood pressure was found with a peak systolic pressure in spring and peak diastolic pressure in summer. A circannual rhythm in urinary norepinephrine was statistically significant only in the women with a peak in winter, out of phase with the circannual rhythm in blood pressure. In plasma aldosterone, the highest values were found during fall and winter with statistical significance reached at the p less than .05 level in the women only. In contrast to the elderly subjects, 87 boys and 107 girls 11 +/- 1.5 (S.D.) years of age studied by the same methodology over one 24-hour span each spread throughout the four seasons showed a circannual rhythm in systolic and diastolic blood pressure and in norepinephrine excretion with a peak during winter. A circannual rhythm of the circadian mesor of the plasma aldosterone concentration was found in the children with highest values in fall and lowest values in spring (when the blood pressure values also were lowest). With all qualifications in mind about possible causal relations between rhythms showing a coincidence or a difference in phase, it appears that there are certain differences in the circannual time structure of cardiovascular and related endocrine functions between children and elderly subjects which may be of clinical importance.

Circadian rhythm in mammary cytoplasmic estrogen receptor content of Balb/C female mice with and without pituitary isografts

Cytoplasmic estrogen receptors were determined by the dextran-coated charcoal method in inguinal breast tissue of three groups of Balb/C female mice 6-8 weeks following subcutaneous implantation into the intact animals of three pituitary glands and three pieces of skeletal muscle (group I), three pituitary glands and three segments of hypothalamic tissue (group II), or three pieces of skeletal muscle (group III) obtained from animals of the same inbred strain as control. A circadian rhythm in estrogen receptor content was statistically quantified by cosinor analysis in the muscle implanted control and the pituitary and hypothalamic implant groups. In the pituitary and muscle implant group the circadian rhythm is of borderline significance with a P-value between 0.05 and 0.10. The timing (acrophase) and extent of change (amplitude) are similar in all three treatment groups. The average receptor content (MESOR) in the two pituitary-implanted groups, which in previous studies were shown to have an increased breast cancer incidence is about twice that of the control group. The reduction in the pituitary induced breast cancer rate by hypothalamic tissue addition to a cancer incidence between the animals with pituitary and muscle isograft and the mice carrying no pituitary at all has also been shown previously in this strain of mice and is not reflected in receptor content.

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.

Differences in the circadian rhythm parameters of urinary free epinephrine, norepinephrine and dopamine between children and elderly subjects

The circadian rhythm in the urinary excretion of free epinephrine, norepinephrine and dopamine was studied in 60 elderly men and 83 women, 77 +/- 8 years of age, in a total of 260 24-hour profiles and in 63 boys and 81 girls, 11 +/- 1.5 years of age, in 144 24-hour profiles. The circadian mesor of all these compounds was increased in the children over that in the elderly subjects while the acrophase remained unchanged in spite of a phase shift of the acrophase of the urine excretion of the elderly in the night hours. The differences in functional state of the sympathetic and adreno-medullary function (and/or response) between children and elderly subjects may have clinical implications.

Circadian rhythm in plasma immunoreactive somatomedin-C in children

Fifteen boys and 27 girls, 11 +/- 2 years of age were studied over a single 24-hour span during the month of June. Statistically significant circadian rhythms of plasma immunoreactive somatomedin-C (SM-C) concentration, immunoreactive growth hormone (hGH) and cortisol concentration were found, which show marked differences in timing. The highest values of somatomedin-C occurred in the early evening hours (acrophase 19:08) in contrast to growth hormone which showed its peak values during the night and cortisol, which peaked in the morning hours. These observations are of interest for the physiologic regulation of somatomedin-C as well as for the clinical evaluation of plasma immunoreactive somatomedin-C concentrations, and for studies of the response of somatomedin-C to hormonal and/or pharmacologic manipulation.

Circadian time structure of endocrine and biochemical parameters in adult onset (type II) diabetic patients

Forty-one endocrine and biochemical serum parameters were studied over a 24-hour span with 6 samples at 4-hour intervals in 20 non-insulin dependent (Type II) diabetics and in 20 non-diabetic subjects matched for sex, age, height and weight. Circadian rhythms were verified by cosinor analysis. Group-synchronized circadian rhythms were detected in diabetic and non-diabetic subjects with no statistically significant difference in any of the rhythm parameters (rhythm adjusted mean, amplitude and acrophase) in: Aldosterone, cortisol, insulin, 17-OH progesterone, prolactin, testosterone, TSH, and in serum albumin, creatine phosphokinase (CPK), serum iron, inorganic phosphate and total protein. Statistically significant (p less than .05) circadian rhythms in both groups with a difference in some parameters between the diabetic and the non-diabetic subjects, which were verified by the Bingham Test (p less than .05) were found with a difference in the mesor in cholesterol, glucose, urea nitrogen (BUN), in the amplitude in C-peptide and in the acrophase in triglycerides, globulin and reverse T3 (rT3). Statistically significant circadian rhythms were detected as a group phenomenon for the diabetics only in progesterone, free and total T4, chloride, calcium, bilirubin and LDH and in the non-diabetic subjects only in ACTH, LH, total T3, alkaline phosphatase, uric acid and potassium. In the remainder of the functions studied, a circadian rhythm was detectable with statistical significance by cosinor analysis as a group phenomenon neither in the diabetics nor in the matched non-diabetic controls (DHEA-S, estradiol, FSH, GH, glucagon, free T3, sodium, GOT and gamma GT). In the absence of a detectable circadian rhythm as group phenomenon, the circadian mean was different between the diabetics and the non-diabetic subjects in sodium, chloride and calcium which were higher in the diabetic patients and serum LDH which was lower. In a comparison of endocrine determinations in the two groups, the circadian mean or mesor in T3 was lower in the diabetics and ACTH higher, without corresponding changes in TSH or in corticosteroids. The circadian time structure of Type II diabetic patients thus seems to be very similar to that seen in non-diabetic subjects of the same sex, age, weight and height. The minor differences found in some rhythm parameters will have to be confirmed or excluded in larger numbers of subjects. The higher circadian mean ACTH concentrations without change in steroid rhythm parameters observed in this group is interesting but will also require confirmation.(ABSTRACT TRUNCATED AT 400 WORDS)

Circadian rhythm of TSH in adult onset non-insulin dependent (type II) diabetics with altered thyroid state

Twenty adult onset non-insulin dependent (Type II) diabetic patients and twenty non-diabetic subjects matched for sex, age, height and weight were studied. The diabetes was controlled by diet only in 10 patients and by oral hypoglycemic agents in 10. All patients were diurnally active and rested at night. Blood was sampled at 4-hour intervals over a 24-hour span (6 samples). TSH, total T3 and total T4 were determined by radioimmunoassay. The circadian rhythm in TSH was statistically significant by cosinor analysis and was comparable in all rhythm parameters in diabetics and non-diabetics. The rhythms of total T3 and T4 also seem to persist with comparable timing although the small number of subjects did not allow rhythm detection at the 5 per cent level in all groups. The circadian mean of the total T3 plasma concentration in the diabetics, however, was statistically significantly lower than the usual range of this laboratory and the total T4 was elevated but within the usual range. The changes in total T3 and T4 were most pronounced in the patients on oral hypoglycemic agents. This study indicates persistence of a circadian rhythm in TSH (and presumably also in the plasma concentrations of total T3 and T4) in non-insulin dependent diabetic patients in spite of a lowered circadian mean concentration of total T3 and a slightly but statistically significantly higher total T4 than in the matched non-diabetic subjects. The altered thyroidal state in the diabetic patients thus does not interfere with the circadian periodic secretion of TSH.

Circadian variations in plasma immunoreactive insulin (IRI) and C-peptide concentrations in adult onset (type II) diabetes mellitus

Plasma immunoreactive insulin (IRI), C-peptide and serum glucose concentrations were determined in 19 adult onset non-insulin dependent (type II) diabetics, in one adult onset diabetic on insulin and in 20 non-diabetic subjects matched for sex, age, weight and height. The subjects lived on a schedule of diurnal activity and nocturnal rest (21:00 to 06:00) at Berceni Clinical Hospital, Bucharest, Romania and ate three meals at 08:30, 13:00 and 18:30 and a snack at 10:00 (carbohydrate content: 50 gm, 65 gm, 60 gm and 25 gm respectively). Nine of the diabetic patients were on oral hypoglycemic agents (tolbutamide or meguan), the others were controlled by diet only. Blood was sampled beginning at 08:00 at 4 hourly intervals over a 24-hour span. The circadian variations of IRI, C-peptide and serum glucose were analysed by population mean cosinor. The non-insulin dependent diabetic subjects as a group and the matched non-diabetic subjects showed under the conditions of this study circadian variations in serum glucose, plasma IRI and C-peptide which were identical in timing (acrophase) and amplitude and with the exception of the much higher serum glucose concentrations in the diabetics, not significantly different in the circadian mean concentration (or mesor). The diabetics on oral hypoglycemic agents if investigated separately showed in spite of identical serum glucose concentration a statistically significantly lower circadian mean IRI and C-peptide concentration than either non-diabetic subjects or the diabetics treated by diet only. Acrophase and relative amplitude remained unchanged. Adult onset non-insulin dependent (type II) diabetics maintained on diet only show the same circadian variations in plasma IRI and C-peptide as non-diabetic matched for sex, age, height and weight. The adult onset diabetic on insulin showed an extremely high serum glucose concentration which varied in its timing over the 24-hr span similar to the other subjects. His plasma IRI concentration was about ten times that of the non-diabetic or other diabetic subjects in this study. There was no statistically recognizable circadian variation of IRI. In contrast C-peptide was found at the same concentration as found in the other two groups and showed in all rhythm parameters an identical circadian variation. The circadian acrophase of plasma IRI and C-peptide concentrations in adult onset diabetics and the non-diabetics is the same.(ABSTRACT TRUNCATED AT 400 WORDS)

Circannual variation of intestinal cell proliferation in BDF1 male mice on three lighting regimens

BDF1 male mice were studied over a 24-hr span in winter, spring, summer and fall. For three weeks prior to study, one-third of the animals were kept under a lighting regimen of 8 hr light alternating with 16 hr of darkness (LD 8:16), one-third on a lighting regimen of LD 12:12 and a remainder on a lighting regimen of LD 16:8. During each study, subgroups of animals on all three lighting regimens were killed at 4-hr intervals over a 24-hr span. Twenty minutes prior to being killed, the animals received 5 microCi of [3H]-thymidine/0.2 ml/20 gm of body weight intraperitoneally. The thymidine uptake in the DNA of the colon and of the small intestine were studied as an index of cell proliferation. A circadian rhythm in [3H]-thymidine uptake in the colon was found and validated by cosinor analysis. This rhythm was similar in acrophase and amplitude in the animals kept on LD 8:16 and LD 12:12. Also in the mice on LD 16:8, there was a statistically significant circadian rhythm of [3H]-thymidine uptake in the DNA of the colon during all four seasons. The acrophases of this rhythm, however, varied widely suggesting free running. A circadian rhythm of [3H]-thymidine uptake in small intestine was less consistent. In animals on all three lighting regimens, however, a circannual variation of [3H]-thymidine uptake in DNA in colon and small intestine was found with the highest uptake during summer. This study indicates that a lighting regimen of LD 16:8 does not reliably synchronize the circadian rhythm of [3H]-thymidine uptake in the colon. It further shows a circannual rhythm of this function in the colon and in the small intestine which persists under three lighting regimens (LD 8:16, 12:12 and 16:8) maintained for three to four weeks prior to being killed.

Circadian and circannual rhythms of hormonal variables in elderly men and women

A group of fourteen men (73 +/- 5 yr of age), and eighteen women (77 +/- 7 yr of age) institutionalized at the Berceni Clinical Hospital, Bucharest, Romania, were studied over a 24-hr span once during each season (winter, spring, summer and fall). All subjects followed a diurnal activity pattern with rest at night and ate three meals per day with breakfast at about 0830, lunch at about 1300 and dinner at about 1830. The meals were similar, although not identical for all subjects during all seasons. On each day of sampling blood was collected at 4-hr intervals over a 24-hr span. Seventeen hormonal variables were determined by radioimmunoassay. Statistically significant circadian rhythms were detected and quantitated by population mean cosinor analysis in pooled data from all four seasons in both sexes for ACTH, aldosterone, cortisol, C-peptide, dehydroepiandrosterone-sulfate (DHEA-S), immunoreactive insulin, prolactin, 17-OH progesterone, testosterone, total T4 and TSH. In women, estradiol and progesterone also were determined and showed a circadian rhythm during all seasons. Total T3 and FSH showed circadian rhythm detection by cosinor analysis in the men only; LH showed no consistent circadian rhythm as group phenomenon in men or women. A circannual rhythm was detected using the circadian means of each subject at each season as input for the population mean cosinor in the women for ACTH, C-peptide, DHEA-S, FSH, LH, progesterone, 17-OH progesterone and TSH. In the men, a circannual rhythm was detected for ACTH, FSH, insulin, LH, testosterone and T3. There were phase differences between men and women in ACTH, FSH and LH. In those functions in which both the circadian and circannual rhythms were statistically significant, a comparison of the amplitudes showed in the women a higher circannual rather than circadian amplitude for DHEA-S. In 17-OH progesterone, TSH and C-peptide, the circadian amplitude in women was larger. In men, the circannual amplitude of T3 was larger than the circadian amplitude and in insulin the circadian amplitude was larger than the circannual amplitude. There was no statistically significant difference between the circadian and circannual amplitudes in the women in ACTH and progesterone and in the men in ACTH and testosterone.

Chronobiology in hematology and immunology

The hematopoietic and the immune systems in all their components are characterized by a multifrequency time structure with prominent rhythms in cell proliferation and cell function in the circadian, infradian, and rhythms in cell proliferation and cell function in the circadian, infradian, and circannual frequency ranges. The circulating formed elements in the peripheral blood show highly reproducible circadian rhythms. The timing and the extent of these rhythms were established in a clinically healthy human population and are shown as chronograms, cosinor summaries and, for some high-amplitude rhythms, as time-qualified reference ranges (chronodesms). Not only the number but also the reactivity of circulating blood cells varies predictably as a function of time as shown for the circadian rhythm in responsiveness of human and murine lymphocytes in vitro to lectin mitogens (phytohemagglutinin and pokeweed mitogen). Some circadian rhythms of hematologic functions appear to be innate and are presumably genetically determined but are modulated and adjusted in their timing by environmental factors, so-called synchronizers. Phase alterations in the circadian rhythms of hematologic parameters of human subjects and of mice by manipulation of the activity-rest or light-dark schedule and/or of the time of food uptake are presented. Characteristically these functions do not change their timing immediately after a shift in synchronizer phase but adapt over several and in some instances over many transient cycles. The circadian rhythm of cell proliferation in the mammalian bone marrow and lymphoid system as shown in mice in vivo and in vitro may lend itself to timed treatment with cell-cycle-specific and nonspecific agents in an attempt to maximize the desired and to minimize the undesired treatment effects upon the marrow. Differences in response, and susceptibility of cells and tissues at different stages of their circadian and circaseptan (about 7-day) rhythms and presumably of cyclic variations in other frequencies are expected to lead to the development of a chronopharmacology of the hematopoietic and immune system. Infradian rhythms of several frequencies have been described for numerous hematologic and immune functions. Some of these, i.e., in the circaseptan frequency range, seem to be of importance for humoral and for cell mediated immune functions including allograft rejection. Infradian rhythms with periods of 19 to 22 days seem to occur in some hematologic functions and are very prominent in cyclic neutropenia and (with shorter periods) in its animal model, the grey collie syndrome.(ABSTRACT TRUNCATED AT 400 WORDS)

Circadian and circannual variations in plasma immunoreactive insulin (IRI) and C-peptide concentrations in elderly subjects

Groups of 49-51 elderly men and women 77 +/- 8 years of age, institutionalized at the Berceni Clinical Hospital, Bucharest, Romania, were studied over a 24 hour span in spring, summer, fall and winter. All subjects followed a diurnal activity pattern with rest at night and ate three meals per day with breakfast at about 08:30, lunch at about 13:00, dinner at 18:30. The meals were similar, although not identical for all subjects during all seasons. On each day of sampling, blood was collected at four hourly intervals over a 24 hrs span. Immunoreactive insulin (IRI) and C-peptide were determined in plasma and glucose (during fall and winter only) in serum. Circadian variations of all three parameters were found and the rhythm parameters were determined statistically by cosinor analysis. The acrophases of the circadian rhythm of IRI and C-peptide were the same during all four seasons. The circadian acrophase of plasma IRI and C-peptide precedes that of serum glucose. The circadian mean concentrations of IRI and C-peptide show a circannual variation with higher values in winter and fall than in spring and summer for plasma insulin and with higher values for summer and fall than in spring for C-peptide. Sex differences in IRI and C-peptide concentrations with higher values in men are manifested during certain circadian and circannual stages but not during others.

Circadian periodicity of the results of frequently used laboratory tests in elderly subjects

The circadian rhythms of twenty-one chemical serum parameters (albumin, alkaline phosphatase, calcium, carbon dioxide content, chloride, cholesterol, creatine phosphokinase (CPK), creatinine, glucose, glutamic-oxalacetic transaminase (GOT), gamma glutamyl transferase (Gamma--GT), lactate dehydrogenase (LDH), inorganic phosphorus, iron, potassium, total bilirubin, total protein, sodium, triglycerides, urea nitrogen, uric acid) and of urinary volume and oral temperature were studied, in October 1981, in a group of 49 elderly subjects (23 men, 73 +/- 6 years of age, and 26 women, 77 +/- 8 years of age) institutionalized at the Berceni Hospital for the aged. Statistically significant circadian rhythms as a group phenomenon were found in all functions except alkaline phosphatase, GOT, and LDH. The timing and the extent of these rhythms are presented. The circadian time structure of body chemistry appears well maintained in old age. Some circadian rhythms show a large enough amplitude to require the establishment of time qualified reference ("normal") ranges (e.g. serum iron). In most others, the circadian amplitudes are small and at present of little or no diagnostic importance. They are, however, of physiologic and pathophysiologic interest indicating an intricate time sequence of metabolic events in the human body.

Circadian rhythm in urinary N-acetyl-beta-glucosaminidase (NAG) of clinically healthy subjects. Timing and phase relation to other urinary circadian rhythms

Urinary N-acetyl-beta-glucosaminidase (NAG), a lysosomal enzyme of renal tubular origin, has been shown to be a sensitive indicator of renal tubular function. This study documents a circadian rhythm in the urinary activity of NAG, statistically validated and quantified by the cosinor method, in 19 female and 15 male human subjects. The acrophase of the circadian rhythm in urinary NAG activity occurs at 09(40) with 95% confidence limits between 08(40) and 12(08) and is similar to the timing of the circadian rhythm in urinary free cortisol. The circadian acrophase of urinary NAG activity lags in timing the circadian rhythms in urine volume, Na and K excretion, and urinary free adrenalin and noradrenalin, by about five to ten hours and the circadian rhythm in creatinine excretion by about 11 hours. These functions with their characteristic phase relations are part of the internal circadian time structure of the human organism, and may provide internal phase references, independent of the "time of day." This study also documents a sex difference in mesor of the circadian rhythms in urinary NAG activity, with female subjects having a higher mesor and amplitude than the male subjects, and in the excretion of creatinine and potassium, with male subjects having a higher mesor and amplitude than the female subjects.

Endocrine circadian time structure in the aged

Thirteen circadian rhythms in plasma hormone levels (ACTH, aldosterone, cortisol, C-peptide, insulin, DHEA-S, estradiol, LH, prolactin, 17-OH progesterone, testosterone, T4 and TSH) were studied in April 1981 in 25 males and 25 females 57 to 91 years of age, institutionalized at the Berceni Hospital for the aged. The radioimmunoassays and the statistical rhythmometric evaluation by the cosinor procedure were done at S. Paul-Ramsey Medical Center, St. Paul, MN, USA. Circadian rhythms were found and quantified for each of these variables. Elderly subjects of both sexes thus maintain a circadian time structure of their endocrine system as a group phenomenon. In comparison with previous data from the Endocrine Rhythms Laboratory ("C. I. Parhon" Institute) and series of younger subjects studied in Minnesota (St. Paul-Ramsey Medical Center) as well as in comparison with data published from other centers, the aged seem to experience an earlier arousal of their endocrine system which may be related to certain disturbances of old age e.g. of sleep. The latter observations will have to be confirmed by additional studies which take both circadian and circannual variations in account.