An Integrative Model of Subcortical Auditory Plasticity

In direct conflict with the concept of auditory brainstem nuclei as passive relay stations for behaviorally-relevant signals, recent studies have demonstrated plasticity of the auditory signal in the brainstem. In this paper we provide an overview of the forms of plasticity evidenced in subcortical auditory regions. We posit an integrative model of auditory plasticity, which argues for a continuous, online modulation of bottom-up signals via corticofugal pathways, based on an algorithm that anticipates and updates incoming stimulus regularities. We discuss the negative implications of plasticity in clinical dysfunction and propose novel methods of eliciting brainstem responses that could specify the biological nature of auditory processing deficits.     

Study of human papillomavirus infection in patients with anal squamous carcinoma

PURPOSE: The purpose of this study was to determine the incidence of human papillomavirus deoxyribonucleic acid (HPV DNA) in anal squamous carcinoma. METHODS: HPV DNA in situ hybridization for HPV Types 6, 11, 16, 18, 31, 33, and 35 was performed on the formalin-fixed, paraffinembedded tissue from 53 perianal and anal squamous carcinomas and 10 controls. RESULTS: HPV DNA sequences were identified in 18 of 53 anal squamous carcinomas (34 percent). All 10 controls were negative for HPV DNA. Of the 18 positive patients, 10 were perianal squamous carcinomas, and 8 were anal canal squamous carcinomas. Six of the perianal carcinomas were positive for HPV Types 6 and 11. The remaining four perianal carcinomas and all eight of the anal canal carcinomas were positive for HPV Types 16 and 18. CONCLUSION: HPV DNA sequences can be identified in anal squamous carcinomas. Anal squamous epithelium is another site where HPV infection may carry a risk for malignant transformation. One-third of anal squamous carcinomas may be associated with prior HPV infection. Patients with anogenital HPV infection should be routinely screened for anal squamous lesions.     

Drug resistant Haemophilus influenzae from respiratory tract infection in a tertiary care hospital in north India

Haemophilus influenzae is an important respiratory pathogen. Emergence of resistance to various antibiotics is a major problem in patient management. A total of 90 strains of H. influenzae were characterized from specimens obtained from patients of acute respiratory tract infection; 13 (14.4%) belonged to type beta. On biotyping, 90% strains belonged to biotype II. The frequency of resistance to various antibiotics was as follows: cotrimoxazole 33.3% ampicillin 21.1%, cephalexin 7.8%, chloramphenicol 7.8%, ciprofloxacin 2.5% erythromycin and tetracycline 5% each. All the ampicillin-resistant strains produced beta-lactamase as detected by nitrocefin disc method. None of the strains exhibited resistance to cefaclor and third generation cephalosporins. The present study showed emergence of variable resistance to ampicillin, cotrimoxazole and other antibiotics. It is important for the clinical microbiology laboratory to monitor drug resistant strains for instituting appropriate antibiotic therapy of respiratory infections due to H. influenzae.     

Characterization of rat100, a 300-kilodalton ubiquitin-protein ligase induced in germ cells of the rat testis and similar to the Drosophila hyperplastic discs gene

Conjugation of ubiquitin to proteins is activated during spermatogenesis. Ubiquitination is mediated by ubiquitin-activating enzyme (E1), ubiquitin-conjugating enzymes (UBCs or E2s), and ubiquitin protein ligases (E3s). Since we previously showed that the activated ubiquitination is UBC4 dependent, we characterized Rat100, a UBC4-dependent E3 expressed in the testis. Analysis of expressed sequence tag sequences and immunoblotting showed that Rat100 is actually a 300-kDa protein expressed mainly in the brain and testis and is similar to the human E3 identified by differential display (EDD) protein and the Drosophila hyperplastic discs gene, mutants of which cause a defect in spermatogenesis. Rat100 is induced during postnatal development of the rat testis, peaking at d 25. It is localized only in germ cells and is highly expressed in spermatocytes, moderately in round and slightly in elongating spermatids. In contrast to UBC4 whose removal from a testis extract abrogates much of the conjugation activity, immmunodepletion of Rat100 from the extracts had little effect. Rat100 therefore has a limited subset of substrates, some of which appear associated with the E3 as the immunoprecipitate containing Rat100 supported incorporation of (125)I-ubiquitin into high molecular weight proteins. Thus, Rat100 is the homolog of human EDD and likely of Drosophila hyperplastic discs. This homology, together with our results, suggests that induction of this E3 results in ubiquitination of specific substrates, some of which are important in male germ cell development.