Search PubMed⌕ Search

Biomedical subjects

E Haus

Publications and source records attributed to E Haus.

At least 37 records · Page 2Linked to original sources
PubMed1996

[Annual endocrine rhythms in man].

Biological rhythms spread over a wide range of frequencies: circadian, ultradian and infradian. Circannual rhythms belong to this latter domain as their period average one year +/- 2 months. The seasonal rhythms in man of melatonin, prolactin, hormones of bone metabolism, ACTH and HCG are here reviewed and the questions raised by their characterization - including methodological problems - their origin and their incidence on health and diseases.

Adrenocorticotropic Hormone↗
PubMed1995

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)

Adolescent↗
PubMed1994

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.

Adult↗
PubMed1993

Chronobiology in laboratory medicine.

A critical amount of information has accumulated over the last decades to allow the application of chronobiology to clinical and laboratory medicine. The tasks faced in laboratory medicine include the quantitative measurement of the multifrequency human time structure in health and disease. For this purpose, it is essential to choose an adequate sample size in order to obtain meaningful results and quantitative endpoints which can be interpreted by inferential statistical techniques. No statistical technique is applicable for all purposes and it is essential that the assumptions underlying each technique and its limitation are well known to the investigator. The multifrequency nature of the human time structure has to be kept in mind in order to avoid erroneous results. Time qualified reference ranges have to be established for high amplitude rhythms. Circadian and/or circannual rhythm alterations have been described as group phenomenon in subjects with epidemiologically determined risk states for common diseases, but will require much further studies for the application to individual subjects. Rhythm parameters are new endpoints in the evaluation of the human time structure in health. Alterations of these parameters may occur as cause or as consequence of disease. Recognition of rhythm abnormalities in disease are critical for a meaningful application of chronopharmacology. Time dependent changes in pharmacokinetics and pharmacodynamics have to be taken into account in the interpretation of drug level determinations. A considerable degree of individuality of timing has been documented in some frequencies. This individuality and the rhythm abnormalities found in disease require the study of reference or marker rhythms. If the complexity of the human time structure is clearly understood and its study pursued in a critical manner with quantitative endpoints, chronobiology opens a new dimension in laboratory and clinical medicine.

Adult↗
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↗
PubMed1990

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.

Adult↗
PubMed1989

Control of a murine plasmacytoma with doxorubicin-cisplatin: dependence on circadian stage of treatment.

In anticipation of the development of clinical chronotherapy and in order to pick clinical test times for doxorubicin and cisplatin trials, two large studies were performed on rats bearing a transplanted plasmacytoma. The circadian timing of each of two anticancer drugs given at precisely equal dose intensities was expected to improve therapeutic benefit over conventionally given (time-unqualified) treatment. In each chronotherapeutic study, maximal benefit and minimal toxic effects were found when cisplatin was administered in the middle to latter part of the daily activity (dark) span, while doxorubicin was administered near the end of the daily resting (light) span for these nocturnally active rodents living on a 12-hour-12-hour or 8-hour-16-hour light-dark schedule. This was true whether doxorubicin or cisplatin was given first and whether there was a lag of only a few hours or a few days between the administration of these two agents.

Animals↗