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Cell surface receptors for gibbon ape leukemia virus (Glvr-1) and marine amphotropic retrovirus (Ram-i) Ram-i (10) and human Glvr-1 (7) cDNAs were cloned into pGEM-7Z (Promega) with their 5' ends adjacent to the SP6 promoter. For mRNA synthesis, the plasmids were linearized and transcribed with SP6 polymerase in the presence of m7G(5')ppp(5')G caps according to the manufacturer's directions (Pharmacia). Xenopus laevis oocytes were injected with 50 nl of mRNA (1 ng/nl) or with an equal volume of H20 and were incubated for 4-6 days at 17'C; then two-microelectrode voltage-clamp recordings or radiolabel uptake assays were performed at room temperature as described (23).Abbreviations: GALV, gibbon ape leukemia virus; Glvr-1, cell surface receptor for GALV; Ram-i, cell surface receptor for amphotropic murine retrovirus; HIV, human immunodeficiency virus; MLV, murine leukemia virus; Mo-MLV, Moloney MLV.

Women with a family history of breast cancer are at increased risk for developing the disease. This study investigated the beliefs of women at high risk for breast cancer (one or more first-degree relatives with breast cancer) about their breast cancer risk and the impact of this information on their surveillance behaviors and psychological distress. The Health Belief Model and the Fear Arousing Communications Theory were used in this study. Two hundred and seventeen women, enrolled in a breast protection program, completed a questionnaire regarding health beliefs and behaviors, social support, and psychological distress. While 94% came in for regularly scheduled mammograms, only 69% came in for regular clinical breast examinations. A discriminant function analysis revealed that increased cancer anxiety decreased regular clinical examinations (coefficient = -.65). Only 40% performed breast self-examination monthly, 10% never performed breast self-examination, and 50% did not perform breast self-examination regularly. High breast self-examination performance prior to coming to the program was the best predictor of current breast self-examination, and high anxiety predicted poor adherence to monthly breast self-examination (multiple R = .61). More than 27% of the women at high risk were defined as having a level of psychological distress consistent with the need for counseling. Women reporting more barriers to screening, fewer social supports, and low social desirability had more psychological distress (multiple R = .75). Higher anxiety was directly related to poor attendance at a clinical breast examination and poor adherence to monthly breast self-examination.(ABSTRACT TRUNCATED AT 250 WORDS)

The host and tissue specificity of retrovirus infection is largely determined by specific cellular receptors that mediate virus entry. Genes encoding these receptors are widely distributed in the genome, and the receptors identified to date show no sequence similarity. We have identified the cellular receptor for amphotropic murine retroviruses, Ram-i, by screening a rat cDNA expression library introduced into amphotropic virus-resistant hamster cells. The 656-amino acid receptor is homologous to the gibbon ape leukemia virus receptor at both hydrophobic termini but is highly divergent in the central hydrophilic region. Both receptors appear to be integral membrane proteins having multiple membranespanning regions. Identification of this family of receptors will help define the evolutionary relationship between retroviruses and their cellular receptors.Retrovirus infection is initiated by binding of retrovirus envelope proteins to specific cellular receptors. Virus interference and chromosome mapping studies indicate the presence of many receptors that are used by different retroviruses, including at least eight receptors on human cells (1). The four retroviral receptors that have been identified to date show no sequence similarities that might suggest important features of proteins that can serve as retrovirus receptors, and the genes for these receptors are distributed on different chromosomes (2-8). Thus it is important to isolate additional receptors to see whether common features become apparent.Identification of the receptor for amphotropic murine retroviruses is also important because of the wide use of amphotropic retroviral vectors for gene transfer, especially in human gene therapy applications (9). Certain somatic cell types are difficult to infect with amphotropic vectors (e.g., hematopoietic stem cells), and although part of this difficulty may be due to the apparent inability of these vectors to infect nondividing cells, modulation of receptor expression may also play a role.Expression cloning of the amphotropic retrovirus receptor has been difficult due to the ability of the virus to infect many cell types from a wide range of species. Chinese hamster ovary (CHO)