Membrane proteins specified by herpes simplex viruses. I. Identification of four glycoprotein precursors and their products in type 1-infected cells.

Polypeptide precursors to the major glycoproteins specified by herpes simplex virus type 1 were identified in immunoprecipitation experiments using antisera that reacted specifically with the viral glycoproteins and their precursors. The results demonstrate that the major glycosylated proteins detected in infected cells are derived from four antigenically distinct polypeptides. Three of these polypeptides become glycosylated in two discrete stages, yielding partially glycosylated intermediates and fully glycosylated products. The final products are the predominant species detected in cytoplasmic virions and in plasma membranes. The fourth polypeptide precursor appears to acquire very little carbohydrate and differs in several respects from the other three precursors.     

A Novel L-ficolin/Mannose-binding Lectin Chimeric Molecule with Enhanced Activity against Ebola Virus

Ebola viruses constitute a newly emerging public threat because they cause rapidly fatal hemorrhagic fevers for which no treatment exists, and they can be manipulated as bioweapons. We targeted conserved N-glycosylated carbohydrate ligands on viral envelope surfaces using novel immune therapies. Mannose-binding lectin (MBL) and L-ficolin (L-FCN) were selected because they function as opsonins and activate complement. Given that MBL has a complex quaternary structure unsuitable for large scale cost-effective production, we sought to develop a less complex chimeric fusion protein with similar ligand recognition and enhanced effector functions. We tested recombinant human MBL and three L-FCN/MBL variants that contained the MBL carbohydrate recognition domain and varying lengths of the L-FCN collagenous domain. Non-reduced chimeric proteins formed predominantly nona- and dodecameric oligomers, whereas recombinant human MBL formed octadecameric and larger oligomers. Surface plasmon resonance revealed that L-FCN/MBL76 had the highest binding affinities for N-acetylglucosamine-bovine serum albumin and mannan. The same chimeric protein displayed superior complement C4 cleavage and binding to calreticulin (cC1qR), a putative receptor for MBL. L-FCN/MBL76 reduced infection by wild type Ebola virus Zaire significantly greater than the other molecules. Tapping mode atomic force microscopy revealed that L-FCN/MBL76 was significantly less tall than the other molecules despite similar polypeptide lengths. We propose that alterations in the quaternary structure of L-FCN/MBL76 resulted in greater flexibility in the collagenous or neck region. Similarly, a more pliable molecule might enhance cooperativity between the carbohydrate recognition domains and their cognate ligands, complement activation, and calreticulin binding dynamics. L-FCN/MBL chimeric proteins should be considered as potential novel therapeutics.     

Production of cellulase and β-glucosidase activities following growth of Streptomyces hygroscopicus on cellulose containing media

The actinomycete, Streptomyces hygroscopicus was shown to be capable of producing extracellular cellulase and cell associated -glucosidase activity during growth on cellulose containing media. Cell homogenates were shown to contain a -glucosidase fraction which was stable for up to 24h. at 30°C and had half-lives of 480min. and 220min. at 40 and 50°C, respectively. The enzyme fraction was also shown to be optimally active at pH 4.0 suggesting that it might represent a suitable supplement for fungal cellulase systems, deficient in -glucosidase activity.     

Viral determinants of the variable sensitivity of herpes simplex virus strains to gD-mediated interference.

Cells that express glycoprotein D (gD) of herpes simplex virus type 1 (HSV-1) resist infection by HSV-1 and HSV-2 because of interference with viral penetration. The results presented here show that both HSV-1 and HSV-2 gD can mediate interference and that various HSV-1 and HSV-2 strains differ in sensitivity to this interference. The relative degree of sensitivity was not necessarily dependent on whether the cell expressed the heterologous or homologous form of gD but rather on the properties of the virus. Marker transfer experiments revealed that the allele of gD expressed by the virus was a major determinant of sensitivity to interference. Amino acid substitutions in the most distal part of the gD ectodomain had a major effect, but substitutions solely in the cytoplasmic domain also influenced sensitivity to interference. In addition, evidence was obtained that another viral gene(s) in addition to the one encoding gD can influence sensitivity to interference. The results indicate that HSV-1 and HSV-2 gD share determinants required to mediate interference with infection by HSV of either serotype and that the pathway of HSV entry that is blocked by expression of cell-associated gD can be cleared or bypassed through subtle alterations in virion-associated proteins, particularly gD.     

Breast augmentation

The optimal technique for breast augmentation has always been debated, and numerous variables fit the needs of the variously shaped patients in our population. The purpose of this article is to present the advantages and disadvantages of the various techniques available in breast augmentation so that, in conjunction with the patient's physical examination, a sound surgical plan can be developed for aesthetic augmentation of the breast.     

Postmastectomy reconstruction of the previously augmented breast: diagnosis, staging, methodology, and outcome

Although many of the health and safety issues associated with breast augmentation have been thoroughly discussed over the past decade, the literature is remarkably silent regarding postmastectomy reconstruction of the previously augmented breast. A retrospective review of the senior author's reconstructive practice was performed for the years 1983 through March of 1999, revealing 21 women who underwent postmastectomy breast reconstruction after previous breast augmentation. For purposes of measuring aesthetic results, these 21 patients were matched to a carefully selected control group of 15 patients. They were also compared with other, larger populations, including 777 of the senior author's other breast reconstructions, the breast cancer registry at the Lombardi Cancer Center in Washington, D.C., and several large, published epidemiologic studies.The interval between the previous augmentation and the diagnosis of breast cancer ranged from 9 months to 18 years, with a mean of 9.3 years. None of the previous augmentation implants was ruptured at the time of mastectomy. Of the nine patients with previous subpectoral augmentation, cancer was detected mammographically in five (56 percent), whereas of the 12 patients with previous subglandular augmentation, cancer was first detected mammographically in only three (25 percent). This difference was not statistically significant (p = 0.2). Overall, eight of the study patients' tumors (38 percent) were first detected mammographically, which is similar to other published reports of breast cancer patients in the general population. Seventy-one percent of the 21 study patients were node-negative, which also compares favorably with other published series.Sixteen of the women with previous augmentation (76 percent) had purely prosthetic reconstructions. Flaps were used in the other five reconstructions (23 percent): three latissimus dorsi flaps (14 percent) and two transverse rectus abdominis musculocutaneous flaps (9 percent). All five flaps were used in patients who had undergone radiation therapy. Throughout the senior author's entire reconstructive practice history, transverse rectus abdominis musculocutaneous flaps were more frequently used [282 of 777 nonaugmented reconstructions (36 percent)], whereas latissimus dorsi flaps were less frequently used [17 of 777 nonaugmented reconstructions (2.2 percent)] (p < 0.001).The cosmetic results of the breast reconstructions in the previously augmented study group were generally good-to-excellent, with a mean score by blinded observers of 3.35 of a possible 4.0. These results were comparable to or better than those in the matched controls, who scored a mean of 3.0.