Atanu Kumar Pati

Alterations of the Characteristics of the Circadian Rest‐Activity Rhythm of Cancer In‐Patients

The aim of the present study was to evaluate the characteristics of the circadian rest‐activity rhythm of cancer patients. Thirty‐one in‐patients, consisting of 19 males and 12 females, were randomly selected from the Regional Cancer Center, Pandit Jawaharlal Nehru Medical College, Raipur, India. The rest‐activity rhythm was studied non‐invasively by wrist actigraphy, and compared with 35 age‐matched apparently healthy subjects (22 males and 13 females). All subjects wore an Actiwatch (AW64, Mini Mitter Co. Inc., USA) for at least 4–7 consecutive days. Fifteen‐second epoch length was selected for gathering actigraphy data. In addition, several sleep parameters, such as time in bed, assumed sleep, actual sleep time, actual wake time, sleep efficiency, sleep latency, sleep bouts, wake bouts, and fragmentation index, were also recorded. Data were analyzed using several statistical techniques, such as cosinor rhythmometry, spectral analysis, ANOVA, Duncans multiple‐range test, and t‐test. Dichotomy index (I<O) and autocorrelation coefficient (r24) were also computed. The results validated a statistically significant circadian rhythm in rest‐activity with a prominent period of 24 h for most cancer patients and control subjects. Results of this study further revealed that cancer patients do experience a drastic alteration in the circadian rest‐activity rhythm parameters. Both the dichotomy index and r24 declined in the group of cancer patients. The occurrence of the peak (acrophase, Ø) of the rest‐activity rhythm was earlier (p<0.001) in cancer patients than age‐ and gender‐matched control subjects. Results of sleep parameters revealed that cancer patients spent longer time in bed, had longer assumed and actual sleep durations, and a greater number of sleep and wake bouts compared to control subjects. Further, nap frequency, total nap duration, average nap, and total nap duration per 1 h awake span were statistically significantly higher in cancer patients than control subjects. In conclusion, the results of the present study document the disruption of the circadian rhythm in rest‐activity of cancer in‐patients, with a dampening of amplitude, lowering of mean level of activity, and phase advancement. These alterations of the circadian rhythm characteristics could be attributed to disease, irrespective of variability due to gender, sites of cancer, and timings of therapies. These results might help in designing patient‐specific chronotherapeutic protocols.

Morningness – eveningness preference in Indian school students as function of gender, age and habitat

Abstract The aim of the present study was to investigate morningness – eveningness preference in Indian school students as function of gender, age and habitat. A random sample of 2742 school students, consisting of 1487 males and 1255 females, participated in the study. They were divided into four clusters on the basis of their age, i.e. 8 – 11 y, 12 – 15 y, 16 – 19 y, and 20 – 23 y. In addition they were further categorised into two groups on the basis of their place of abode (habitat), i.e. city versus rural. Each student was classified either as morning type (MT) or evening type (ET) or intermediate type (IT) on the basis of his/her performance on a Lark-Owl test, a type of morningness – eveningness questionnaire (MEQ). Prevalence of MT, IT and ET in the studied population was 35.34% (969), 62.73% (1720) and 1.93% (53), respectively. The males and females differed significantly on their mean scores (p < 0.05), i.e. the former group had a higher score as compared with the latter group. The prevalence of IT was the highest in the studied population, irrespective of gender and age. While this observation was in agreement with those reported earlier, other components of our results differed dramatically in that the percentage of evening trait was extremely low (1.93%) and that of morning trait (35.34%) was considerably higher. Further, a statistically significant relationship was discovered between: (1) age and chronotype (p < 0.001), and (2) habitat and chronotype (p < 0.011). In a nutshell, although the results of the present study corroborate with the most of the earlier findings in terms of dominancy of intermediate trait, it does not support those identical reports where the prevalence of morningness or eveningness is concerned. Could this discrepancy be attributed to latitudinal factor? Thus findings reported in this paper definitely open up new avenues for future research.

Overestimation/underestimation of time: concept confusion hoodwink conclusion

Cognitive science is emerging as one of the engaging areas of research in the domain of neurosciences, human behavior and chronobiology. Mechanisms of short-term time perception continue to baffle scientists in these disciplines. The wide arrays of methodologies used to ascertain human abilities to estimate short-time intervals give rise to diverse interpretation of research outputs. The frequently used terminologies, viz., over- or under-estimation/production or reproduction seem to be the profound cause for misinterpretation and misconception of results. In this article we elucidate research carried out on short-interval time estimation and resolve conceptual misapprehensions on its underlying mechanisms.

Effects of simulated hypo- and hyper-reproductive conditions on the characteristics of circadian rhythm in hypothalamic concentration of serotonin and dopamine and in plasma levels of thyroxine, triiodothyronine, and testosterone in Japanese quail, Coturnix coturnix japonica.

In this study, hypo‐ and hyper‐reproductive conditions, as measured by concentrations of plasma testosterone in male Japanese quail held on long days LD 16:8, were experimentally simulated with injections of 5‐hydroxytryptophan (5‐HTP) and L‐dihydroxyphenylalanine, (L‐DOPA) with 8 h and 12 h phase angle differences between them in intact and melatonin‐treated birds. The effects of these treatments were assessed on the characteristics of the circadian rhythm in the hypothalamic concentration of serotonin (5‐HT), dopamine (DA), and plasma levels of thyroxine (T4), triiodothyronine (T3), and testosterone (T). These rhythms were also studied in sham‐operated (SO), pinealectomized (Px), vehicle‐ (Veh), and melatonin (Mel)‐treated birds. On the basis of the circadian mesors of the testosterone rhythms, three distinct categories could be identified: category A (i.e., normal breeding concentrations of plasma testosterone), which includes control, sham‐operated, and vehicle‐treated groups; category A+ (i.e., concentrations of plasma testosterone higher than that found in normal breeding quail), which includes 12 h, 12 h+vehicle‐treated, and Px quails; and category A− (concentrations of plasma testosterone lower than that found in normal breeding quail), which includes 8 h, melatonin‐, and 12 h+melatonin‐treated groups. It is evident that in normal and hypergonadal conditions (i.e., birds belonging to categories A and A+) the circadian rhythm in hypothalamic serotonin maintained a positive phase angle of about 16 h. In contrast, birds of category A− (i.e., in a hypogonadal condition) exhibited a negative phase angle of about 2 h. The present results clearly suggest that the internal phase relationship between the circadian rhythms in hypothalamic serotonin and dopamine might play a crucial role in strategizing and conferring a particular reproductive status to the birds. The role of circadian mechanisms involving circulating thyroid hormones in conferring reproductive status is completely ruled out, as no definite internal phase angle between these two hormonal rhythms was witnessed vis‐à‐vis different treatment groups. The testosterone peaks always occurred at the same time irrespective of breeding status of the bird, but with significant variation in its amplitude (high in hypergonadal and low in hypogonadal condition). It is suggested that administration of 5‐HTP and L‐DOPA at specific time interval and variation in pineal functions that modulate reproductive responses also alter the circadian pattern (acrophase and amplitude) of hypothalamic serotonin and dopamine, maintaining a specific phase relation between these cycles and breeding status. These findings strengthen our previous reports that a specific circadian phase relation of serotonergic and dopaminergic oscillations regulates reproduction. The present study strongly supports interdependence and specific relation of the two systems (gonadal activity and circadian pattern/phase relation of neural oscillation) in both natural and experimentally simulated conditions.

Variability in the characteristics of ultradian and circadian rhythms in plasma levels of growth hormone in the Indian walking catfish, Clarias batrachus

The plasma profile of growth hormone (GH) was monitored in the freshwater catfish, Clarias batrachus over a single 24-h transverse timescale in the middle of each month starting from March to August. This period included different physiological status of the fish and also varying environmental photoperiod and ambient temperature. Statistically significant ultradian rhythm in GH was detected in all the months of study. Of the two ultradian peaks, one was located invariably in the early photophase with the other one in the early scotophase. During the period of intense reproductive activity (June and July), circadian rhythm in GH was also recorded in addition to ultradian rhythm. The 24-h average (Mesor) and amplitude of ultradian rhythm of GH were high in March and April coinciding with the increase in photoperiod, temperature and feeding activity. Mesor increased further in May, reaching the maximum in June with a further rise in the water temperature and intense gonadal activity, but the amplitude declined during these months. In the breeding month of July, Mesor declined moderately and amplitude declined further. In August, Mesor and amplitude both attained minimum levels. In July and August one of the ultradian peaks overlapped with the circadian peak of the GH rhythm and the circadian peaks appeared in the night, while in other months it appeared in the early morning or at midday. Synchronization of one of the ultradian peaks with that of the circadian peak in GH in the night of July and August might provide physiological advantage for the execution of breeding at the coolest part of the day. The rhythmic patterns of GH secretion might have a strong correlation with the changing photoperiod, temperature, and feeding and reproductive activity. The observed temporal organization in GH in C. batrachus may have physiological consequences that might provide suitable milieu for the regulation of its somatic and gonadal growth, and execution of reproductive activity.

Circadian rhythms of locomotor activity in Indian walking catfish, Clarias batrachus.

The circadian rhythm of locomotor activity was assayed in both sexes of Clarias batrachus using infrared sensors connected to an Angus event recorder. Circadian parameters of locomotor activity rhythm, such as rhythm-adjusted average (Mesor), amplitude (A), acrophase (Ø) and period (τ), were determined in C. batrachus maintained under LD 12:12 (I), DD, LD 12:12 (II) and LL for given number of days in each schedule. Each individual fish was exposed to different LD schedules in the order mentioned above. Results of this study revealed that (1) C. batrachus is nocturnal; (2) it exhibits LD-entrainment of its locomotor activity that free-runs under constant conditions; and (3) the period of its locomotor activity rhythm is independent of the factor gender. It appears that multiple oscillators underlie the overt circadian rhythm of locomotion in C. batrachus. This catfish is an important commercial species and understanding of its circadian clock might help in the optimization of its management and pisciculture practices.

Implications of the study of rest – activity circadian rhythm in head and neck cancer patients

Abstract Rhythm alterations consisting of decrease in amplitude, modification in peak time, including the suppression of one or several circadian outputs have been reported in patients suffering from breast, ovarian and colorectal cancer. The aim of the present study was to evaluate the rest – activity circadian rhythm in patients suffering from head and neck cancer. Nine patients were randomly selected from the indoor ward of the Regional Cancer Center, Raipur, India. Rest – activity rhythm and various sleep parameters in these patients were studied non-invasively by using wrist actigraphy. A statistically significant circadian rhythm in rest – activity was validated in all cancer patients. They had lower activity levels (p < 0.05) and amplitudes (p < 0.05) as compared to their respective controls. Further, the fragmentation index was found to be more in male cancer patients as compared with their respective female (p < 0.05) and healthy male (p < 0.05) counterparts. In addition, female cancer patients experienced better sleep efficiency (p < 0.05) and had longer actual sleep time (p < 0.05) as compared to male cancer patients. We conclude that the 24-h average activity and amplitude of rest – activity circadian rhythm declined in head and neck cancer patients. A larger peak spread in the circadian rhythm in rest – activity of cancer patients was discovered. Therefore, the scheduling of therapies should be based on patient-specific individual findings.

PATTERN OF SHIFT ROTA MODULATES ORAL TEMPERATURE CIRCADIAN RHYTHM AND SLEEP-WAKEFULNESS PROFILES IN SHIFT WORKERS

Twenty four shift workers (8 from a steel industry and 16 from a Government hospital) participated in the study. The subjects were instructed to self-measure oral temperature, 4 6 times a day for about three weeks. Sleep quantity and quality for each subject were analysed with the help of an appropriate inventory. The data were analysed by cosinor and power spectrum methods. The frequency of circadian rhythm detection was in the order of 48% in senior nurses, 29% in steel plant workers and 14% in junior nurses. These were also complemented by the results of power spectrum analysis. Present results suggest that rhythms of subjective fatigue and subjective drowsiness are governed neither by oral temperature oscillator nor by the sleep/wake cycle oscillator. The results show that shift rotation pattern chiefly modulates the circadian time structure of shift workers. It is also suggested that the phenomenon of circadian rhythm desynchronization in oral temperature appears to be independent of per day total sleep length.

Interval timing as function of methods of estimation – a study on cohorts of young Indians

The present study is planned to study the pattern/variation in subjective estimation of an array of short-intervals using two popular methods, time reproduction (TR) and time production (TP) prospectively. In the first study, the subjects estimated the short-intervals 5 s, 10 s, 15 s, 30 s, 60 s, and 120 s with time reproduction (TR). In the second study, the same target intervals were estimated using time production (TP) method. The short-intervals were estimated with both TP and TR using the “TimeProd” software (Cajochen et al. 2011). In aggregate, 173 randomly chosen apparently healthy subjects including male and female voluntarily participated in these studies. Out of these, 110 subjects (median age = 23.0 y) participated in a time estimation task with TR method and 63 subjects (median age = 23.0 y) estimated the same intervals with TP method. In both methods, randomly selected subjects including females and males estimated the target intervals during 14:00–16:00 h. The target intervals were randomly presented to the subjects in triplicates. The average of two nearest estimates was converted to duration judgment ratio, “theta (θ)”. Results confirmed a significant methodological difference in estimation of 5 s, 10 s, 60 s, and 120 s. The estimates of all intervals were near to accuracy with TR method only. The frequencies of accurate estimates of 5 s and 120 s were higher with TR than TP method. Variance was found to be greater in estimation with TP than TR method for all target intervals. Coefficient of variance (CV) was increasing and decreasing in TR and TP methods. The gender difference was found in time production of 120 s only. It could be concluded that variations do exist in the pattern of interval timings in time production and time reproduction methods, on account of different underlying memory components. Short-intervals perceived accurately with the time reproduction method. The imperative finding is that the nature of CV may vary in interval timing as a function of method. It also seems that effects of gender and intervals are method dependent.

Assessment of Anxiety Level and Mental Health Status in Spouses and Children of Day-Working and Shift-Working Men

The present study was aimed at assessing the effects of the unusual schedules of shift-working men on anxiety and mental health of their spouses and children. The anxiety and mental health of 396 subjects that include 133 spouses and 263 children of day-working and shift-working men were monitored by employing specific inventory. Anxiety scales (trait, state and free-floating) and mental health inventory were administrated to each subject. Results indicate that the average levels of free-floating anxiety for the spouses and children of shift-working men were found to be significantly higher in comparison with that of their counterparts sampled in the family of day workers. This was also true when data were segregated with respect of gender and compared. Except in female children of shift workers all other groups of children had statistically significantly higher level of state anxiety as compared with that of their respective mothers. The results of this study further reveal that the spouses of shift-working men exhibited lower mental health rating as compared with the spouses of day-working men. Furthermore, a significant negative relationship was noticed between anxiety and mental health in all cases excepting in spouses of shift-working men for state anxiety. Although the findings of the present study could be attributed to the irregular routine of shift workers, it appears mandatory to carryout further intensive studies to draw convincing conclusions.