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Mammalian sex chromosomes arose from a pair of homologous autosomes that differentiated into the X and Y chromosomes following a series of recombination suppression events between the X and Y. The stepwise recombination suppressions from the distal long arm to the distal short arm of the chromosomes are reflected as regions with distinct X-Y divergence, referred to as evolutionary strata on the X. All current methods for stratum detection depend on X-Y comparisons but are severely limited by the paucity of X-Y gametologs. We have developed an integrative method that combines a top-down, recursive segmentation algorithm with a bottom-up, agglomerative clustering algorithm to decipher compositionally distinct regions on the X, which reflect regions of unique X-Y divergence. In application to human X chromosome, our method correctly classified a concatenated set of 35 previously assayed X-linked gene sequences by evolutionary strata. We then extended our analysis, applying this method to the entire sequence of the human X chromosome, in an effort to define stratum boundaries. The boundaries of more recently formed strata on X-added region, namely the fourth and fifth strata, have been defined by previous studies and are recapitulated with our method. The older strata, from the first up to the third stratum, have remained poorly resolved due to paucity of X-Y gametologs. By analyzing the entire X sequence, our method identified seven evolutionary strata in these ancient regions, where only three could previously be assayed, thus demonstrating the robustness of our method in detecting the evolutionary strata.

Objective:To evaluate the effect of different lipid fractions on auditory brainstem evoked responses in hyperlipidaemia.Method:We conducted a single institution (medical college), prospective, cross-sectional study of 25 hyperlipidaemic patients and 25 normolipidaemic controls, all with a normal hearing threshold on pure tone audiometry. Brainstem evoked response audiometry results were recorded in both groups. The hyperlipidaemic group were further divided into two subgroups, based on the serum value of each lipid fraction: those with less than and those with greater than the mean serum value. These two subgroups were further compared with the control group.Results:The hyperlipidaemic and normolipidaemic groups had statistically significant differences for all audiometry waves apart from the wave I and the III–V interpeak latencies. The subgroups had a statistically significant difference in brainstem evoked responses. We found a statistically significant association between low-density lipoproteins and many waveforms in the hyperlipidaemic group.Conclusion:We found that low-density lipoproteins were significantly associated with many waveforms in hyperlipidaemic patients. Thus, low-density lipoproteins may be important in auditory dysfunction. [ABSTRACT FROM PUBLISHER]

Background : Cisplatin-induced ototoxicity shows high interindividual variability and is often accompanied by transient or permanent tinnitus. It is not possible to identify the susceptible individuals before commencement of the treatment. We conducted a prospective, randomized and observational study in a tertiary care centre and evaluated the effects of different doses of cisplatin on hearing. MATERIALS and Methods : Fifty-seven patients scheduled for cisplatin-based chemotherapy were included in the study. All patients were divided into three groups depending on the dose of cisplatin infused in 3 weeks. Results : The subjective hearing loss was found in seven patients, while six patients had tinnitus during the chemotherapy. The hearing loss was sensorineural, dose dependent, symmetrical, bilateral and irreversible. Higher frequencies were first to be affected in cisplatin chemotherapy. Conclusion: As use of high-frequency audiometry is still limited in research work only, we need a strict protocol of adding high-frequency audiometry in the cisplatin-based chemotherapy regimen. [ABSTRACT FROM AUTHOR]

Killian polyp is predominantly found in children and any sinonasal tumor in elderly presenting with epistaxis and pain usually indicates malignant growth until proved otherwise. We present an unusual case of Killian polyp in an elderly patient that behaved as a malignant tumor. This case report reminded us that paranasal sinuses are still dark hollow mysterious cavities, and we should take utmost clinical acumen in managing such cases. [ABSTRACT FROM AUTHOR]