A three-dimensional cryo-electron microscopy structure of the bacteriophage phiKZ head.

The three-dimensional structure of the Pseudomonas aeruginosa bacteriophage phiKZ head has been determined by cryo-electron microscopy and image reconstruction to 18A resolution. The head has icosahedral symmetry measuring 1455 A in diameter along 5-fold axes and a unique portal vertex to which is attached an approximately 1800 A-long contractile tail. The 65 kDa major capsid protein, gp120, is organized into a surface lattice of hexamers, with T = 27 triangulation. The shape and size of the hexamers is similar to the hexameric building blocks of the bacteriophages T4, phi29, P22, and HK97. Pentameric vertices of the capsid are occupied by complexes composed of several special vertex proteins. The double-stranded genomic DNA is packaged into a highly condensed series of layers, separated by 24 A, that follow the contour of the inner wall of the capsid.

Spectrum of oral manifestations of HIV/AIDS in the Perm region (Russia) and identification of self-induced ulceronecrotic lingual lesions.

OBJECTIVE: To study the frequency and spectrum of oral manifestations of HIV-infected drug-users in the Perm region. SUBJECTS: 104 seropositive HIV-infected drug-users (69 male, 35 female; ages 15 to 32 years; 13 co-infected with hepatitis viruses) and 13 AIDS-infected drug-users (7 male, 6 female; ages 16 to 37 years; 12 co-infected with hepatitis viruses). RESULTS: The most frequent forms of oral mucosal lesions in the HIV-infected group -- candidiasis (32.7%), herpetic lesions (15.4%), cheilitis glandularis (3.9%), recurrent aphthous stomatitis (2%). Regional lymphadenopathy was observed in 31% cases. The ulceronecrotic oral mucosal lesions were seen in the sublingual region and tongue in 11.5% patients and manifested with pain, dysarthria, dysphagia, and dysgeusia. These lesions were found in drug-users who injected the opioids sublingually. AIDS patients had oral candidiasis (84.6%), herpetic lesions (53.8%), recurrent aphthous stomatitis (15.4%) and cheilitis glandularis (7%). All AIDS-patients had severe xerostomia, and 15.4% had unilateral or bilateral swelling of the parotid glands. Generalized ulceronecrotic gingivostomatitis was found in 50% of the patients but the sublingual ulceronecrotic lesions were not identified. CONCLUSIONS: 1. The spectrum of oral cavity lesions of HIV/AIDS patients in Perm region is widespread enough. 2. Dissemination of oral cavity lesions is increasing in proportion of disease progression. 3. Dental care of HIV/AIDS patients should include periodic oral examinations to monitor their disease progression and to alleviate symptoms of oral opportunic and neoplastic diseases, to improve the life-style of the patients infected with HIV.