Short-duration judgment in young Indian subjects under 30 h constant wakefulness.

The present study aimed to investigate probability of a possible endogenous circadian rhythm in human cognitive attribute to estimate short intervals. Apparently healthy young males and females were selected for our study. Eight subjects prospectively produced the short-time intervals 10 s and 60 s at 2 hourly intervals in 30 h constant routine (CR) study conducted in spring (CR-1). The study was repeated again in autumn (CR-2) in the remaining eight subjects. The established circadian markers, namely serum cortisol, salivary melatonin levels and tympanic temperature were also measured either in CR-1 or CR-2. Oral temperature was measured simultaneously. Circadian rhythms were validated in serum cortisol, salivary melatonin, oral, and tympanic temperatures. Circadian rhythm in 60 s estimates was observed in a few subjects and in all males at group level in CR-1. The cognitive attribute to perceive short intervals vary as function of season. The results provide evidence in support of interaction among the interval, circadian and circannual timing systems in human.

Blood pressure variability and pedigree analysis of nocturnal SBP dipping in Kumbas from rural Chhattisgarh, India.

Family is the smallest unit of people to share most of the lifestyle, environmental and genetic factors. They are likely to have similarity in many physiological and behavioural aspects. Therefore, we designed a protocol to test the effect of large rural Indian families living together (Kumbas), on blood pressure variability. We also investigated the hypothesis that ‘nocturnal dipping’ in systolic blood pressure (SBP) is not heritable. Members of two families (1 and 2) consisting of 3-4 generations willingly participated in the study. Both families (natives of Chhattisgarh) belong to reasonably peaceful rural area and are financially stable. Farming is the main occupation of the members of both families. Few members of the families had jobs or small business. The null hypothesis regarding heritability of nocturnal dipping trait was accepted based on data emanating from either of the studied families. Hourly-averaged values depicted less variation in males and females of family 1 from midnight to early morning at around 06:00, as compared to that in males and females of family 2. The 24 h averages of BP in family 2 were significantly higher as compared to that in family 1. Further, in family 2 the peaks of SBP, diastolic blood pressure (DBP) and mean arterial pressure (MAP) occurred significantly earlier as compared to that in family 1. The peak spread of SBP, DBP, heart rate (HR), MAP and pulse pressure (PP) among the members of family 1 was narrower than that for the members of family 2. Arbitrary cut-off values for classification of dipping, small sample size, and age dependency of nocturnal dipping might have marred outcome of the pedigree analysis of nocturnal dipping trait in this study. We have a hunch that the family shares typical temporal ups and downs in 24 h BP and HR. The above hypothesis needs confirmation based on studies with large data set involving subjective and objective assessment of the effects of psychosocial factors on BP and HR variability.

Do thyroid and testis modulate the effects of pineal and melatonin on haemopoietic variables in Clarias batrachus.

Involvement of pineal and its major hormone, melatonin, in the process of erythropoiesis in a freshwater catfish, Clarias batrachus has been investigated. The study was conducted during four phases, namely preparatory phase, spawning phase, postspawning phase and late postspawning phase of its annual reproductive cycle. During each phase a fish received either melatonin injections or subjected to pinealectomy. In addition, each fish in all the groups, received either iopanoic acid or cyproterone acetate or vehicle in the morning or late afternoon. Results clearly indicate that melatonin stimulates the rate of erythropoiesis in Clarias batrachus. It appears that the extent of stimulation depends upon the phase of the annual reproductive cycle. However, in general, the pineal- or melatonin-induced modulation of blood variables is gonad dependent and thyroid seems to play a time of the day dependent subtle role.

Nest architecture of a bagworm species: Rhythmic pattern in the arrangement of sticks.

Nest architecture of a bagworm species, Clania crameri was examined. Fortytwo bags (nests) were collected from the host plant, Clerodendron indicum and number of sticks used in each bag was counted. Furthermore, length of each stick in each nest was measured (in mm) clockwise one after another serially beginning with the longest stick. The data obtained were subjected to frequency analysis and power spectrum analysis. Results clearly reveal that the larvae of bagworms do not glue together sticks of different size randomly but with a definite pattern.