Sleep architecture at 4300 m altitude in a sample of Indian lowlanders.

The present study aimed to evaluate sleep architecture at 4300m in a sample of 10 healthy Indian lowlanders, mean age 25.7±5.1 yrs. Polysomnography on two consecutive nights each was performed at sea level and 4300 m, the first night for adaptation and the second one for actual recording. Total sleep time reduced from 433.33±8.95 to 412.06±13.13 minutes (P<0.0005), sleep latency increased from 11.56±6.85 to 22.22±7.95 minutes (P<0.0025), deep NREM sleep (S3+S4) reduced from 79.56±28.45 to 45.39±25.32 minutes (P<0.01), light NREM sleep (S1+S2) increased from 272.94±20.63 to 296.72±23.24 minutes (P<0.05), REM decreased from 80.89±7.65 to 69.94±11.30 minutes (P<0.02) and periodic breathing was present in 4 of 10 participants on the second night at 4300 m. Decreased sleep quality (P<0.0005) and increased sleep disturbances (P<0.0005) were reported in subjective ratings at high altitude. Changes in sleep architecture similar to but of a greater magnitude are present on the second night of staged induction to 4300 m, than reported at 3500 m in our earlier study.

Cloning and sequencing of complete tau-crystallin cDNA from embryonic lens of Crocodylus palustris.

tau-Crystallin is a taxon-specific structural protein found in eye lenses. We present here the cloning and sequencing of complete tau-crystallin cDNA from the embryonic lens of Crocodylus palustris and establish it to be identical to the a-enolase gene from non-lenticular tissues. Quantitatively, the tau-crystallin was found to be the least abundant crystallin of the crocodilian embryonic lenses. Crocodile tau-crystallin cDNA was isolated by RT-PCR using primers designed from the only other reported sequence from duck and completed by 5'- and 3'-rapid amplification of cDNA ends (RACE) using crocodile gene specific primers designed in the study. The complete tau-crystallin cDNA of crocodile comprises 1305 bp long ORF and 92 and 409 bp long untranslated 5'- and 3'-ends respectively. Further, it was found to be identical to its putative counterpart enzyme a-enolase, from brain, heart and gonad, suggesting both to be the product of the same gene. The study thus provides the first report on cDNA sequence of tau-crystallin from a reptilian species and also re-confirms it to be an example of the phenomenon of gene sharing as was demonstrated earlier in the case of peking duck. Moreover, the gene lineage reconstruction analysis helps our understanding of the evolution of crocodilians and avian species.