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Biomedical subjects

D Raviv

Publications and source records attributed to D Raviv.

10 recordsLinked to original sources
PubMed1998

Experiential learning of clinical skills by beginning nursing students: "coaching" project by fourth-year student interns.

To fulfill the requirements for the internship program, fourth-year academic nursing students participated in a leadership program and became coaches for novice students who were beginning their first clinical rotations in the hospital. The concept of coaching is recognized in theory, research, and clinical education as an educational tool, which provides mutual benefits for the coachee and the coach. The project lasted 12 weeks, 2 clinical days per week. The coaches served as a source of support and knowledge and assisted in problem solving for the beginning students. As nurse educators who oversaw the project, the authors summarized the program as it was developed and implemented at the Assaf HaRofeh School of Nursing including problems, revisions, and final conclusions and discussion.

Education, Nursing, Baccalaureate↗
PubMed1997

Conformational transitions in CD4 due to complexation with HIV envelope glycoprotein gp120.

The binding of the surface envelope glycoprotein gp120 to its receptor, CD4, has been well characterized and is the primary basis for the cell tropism of HIV. In this study, the interaction between recombinant soluble CD4 and native membrane-associated CD4 with gp120 is probed by the use of mAbs. Complexation of gp120 with both forms of CD4 induces conformational epitopes that can be defined with specific mAbs. CG1, CG7, and CG8 are three novel mAbs that have a distinct preference for CD4 complexed over noncomplexed with gp120. The epitopes of these unique mAbs were mapped by cross-inhibition with previously characterized mAbs to a region encompassing the CDR2 and CDR3 loops in domain 1 of CD4. Systematic analysis of CG mAbs binding to CD4 and CD4/gp120 complex delineates a region in the D1 domain of CD4 that undergoes conformational rearrangements upon gp120 binding to its receptor.

Animals↗
PubMed1997

Helical epitopes determined by low-stringency antibody screening of a combinatorial peptide library.

Combinatorial phage display peptide libraries are routinely used to map epitopes of specific monoclonal antibodies. In this study we illustrate that these libraries can be used in the analysis of protein structure. By screening libraries at low stringency, a collection of phages can be obtained. These are characterized by the fact that they are recognized by a given monoclonal antibody yet with various affinities. Comparing the random peptides of these phages indicates the common essential residues necessary for antibody recognition. Aligning the inserts based on the detected homology has revealed structural motifs that correspond to secondary protein structures. The envelope protein of HIV-1 has been studied using this approach. A combinatorial phage display library containing a 20 mer random peptide in protein III of the filamentous phage fd-tet has been used to analyze two different monoclonal antibodies directed against gp120. Our results provide experimental evidence that indicate that the C1 domain of gp120 contains an alpha helix.

Amino Acid Sequence↗
PubMed1997

Nursing, a bridge to peace in our region: opinions on mutual co-operation between Israeli and Palestinian professional nurses and nurse educators.

The purpose of this study was to assess the activities and future direction of mutual co-operation of professional nurses from Israel and Judea and Samaria. Questionnaires were distributed to the participants, nurse educators and professional nurses from Judea and Samaria who were attending a workshop in clinical instruction at the Assaf HaRofeh School of Nursing, in Israel. Most of the nurses polled were interested in continued educational dialogue and expanded educational programmes in various nursing specialties both in education and service. The areas that received priority included: intensive care, operating room and emergency room nursing. Areas that received lower priorities included; midwifery, geriatrics and nephrology nursing. The participants expressed positive reactions to continued joint educational activities such as full length courses, workshops, day seminars and joint educational projects. The results showed an overwhelming interest for continued professional ties. Areas in the fields of clinical expertise and nursing education reflected the needs of their respective communities.

Attitude of Health Personnel↗
PubMed1996

Humoral immune response to immunocomplexed HIV envelope glycoprotein 120.

To further our understanding of the nature of HIV-1 immunogenicity, we injected mice with the virus envelope protein gp120 in different configurations: free, complexed with its receptor CD4, and as an immunocomplex with a monoclonal antibody directed against the V3 loop of the protein. Analyses of the polyclonal sera, as well as of monoclonal antibodies produced in each case, allowed us to conclude that the quality of the humoral immune response depended on the complexation state of the antigen. For the free gp120 and gp120-CD4 complex the responses were directed mainly toward conformational epitopes. However, gp120 immunocomplexed with anti-V3 loop Mab produced, in addition, numerous MAbs directed toward linear epitopes. Epitopes were mapped using immunoblots of gp120 cleaved with S. aureus V8 protease and a combinatorial epitope phage-display library. It was found that some of the linear epitopes had been previously identified as T cell epitopes. These results suggest that the immunocomplexed gp120 may be particularly well taken up by antigen-presenting cells, leading to the processing of the gp120 and the efficient presentation of T cell epitopes. Thus immunocomplexation should afford a means for enhancing the immunogenicity of gp120 and improving its presentation.

Amino Acid Sequence↗
PubMed1996

A polymerase chain reaction for the detection of nucleopolyhedroviruses in infected insects: the fate of the Spodoptera littoralis virus in Locusta migratoria.

The Spodoptera littoralis nucleopolyhedrovirus (SlNPV) is a potential pest control agent of Spodoptera spp. As part of our studies to establish the use of this virus, a polymerase chain reaction (PCR)-based method was developed for the detection of viral DNA in infected insects. PCR amplification of the polyhedrin sequences enabled the detection of low levels of viral DNA directly from viral occlusion bodies or from total larval DNA. The use of different sets of synthetic DNA primers allowed us to differentiate between SlNPV and the Autographa californica NPV (AcNPV) and to identify a new AcNPV variant isolated from a cotton pest, Pectinophora gossypiella NPV. The PCR method was also used to test for the possible infection of Locusta migratoria larvae by SlNPV, reported by Bensimon et al., 1987. The progress of SlNPV infection in L. migratoria larvae was monitored by PCR for 2 weeks. The reaction revealed decreasing amounts of viral DNA in infected larvae. During this time, no signs of disease were observed in the infected locusts.

Animals↗
PubMed1993

HIV binding to its receptor creates specific epitopes for the CD4/gp120 complex.

Effective vaccines against the human immunodeficiency virus (HIV) must cope with the genetic variation of the viral envelope (gp120) to combat or prevent acquired immunodeficiency syndrome (AIDS). Here we describe novel epitopes that are accentuated when gp120 complexes with its receptor (CD4). The presentation of these epitopes results through conformational rearrangements in the CD4/gp120 complex. Monoclonal antibodies directed to these epitopes inhibit syncytium formation, thus indicating the potential use of these epitopes as subunit vaccines.

AIDS Vaccines↗
PubMed1991

Individual differences in the self-image of adolescents with learning disabilities: the roles of severity, time of diagnosis, and parental perceptions.

The self-images of 49 adolescents with learning disabilities (Grades 9 through 12, mean age = 15.9) and 49 normally achieving peers (Grades 9 through 12, mean age = 16.0) were compared using the Offer Self-Image Questionnaire (OSIQ). The group with LD scored significantly lower than the comparison group on 4 of the 10 OSIQ scales. Later-diagnosed adolescents with LD scored significantly higher than early-diagnosed adolescents on two of the scales. Severity of the learning disability was not found to be related to self-image scores. In a second study, parental perceptions of the self-images of 28 of the 49 students with LD were studied by administering the Offer Parent-Adolescent Questionnaire (OPAQ) and an informal questionnaire to their parents. On 6 of the 10 OPAQ scales, parents perceived their children as having a lower self-image than the adolescents themselves reported. Significant but moderate relationships were found between parents' perceptions and adolescent self-image scores. Results of the two studies are interpreted in terms of a multidimensional conception of self-image that considers factors inherent to the individual as well as interpersonal and institutional factors.

Adult↗
PubMed1987

Differential susceptibility to phosphatidylinositol-specific phospholipase C of acetylcholinesterase in excitable tissues of embryonic and adult Torpedo ocellata.

The ability of phosphatidylinositol-specific phospholipase C (PIPLC) to solubilize acetylcholinesterase (AChE) in the electromotor system of adult Torpedo ocellata and in the developing electric organ was examined. PIPLC solubilizes significant amounts of the membrane-bound G2 form of AChE throughout embryonic development of the electric organ, as it does in the adult electric organ, the AChE of which we have shown to contain covalently bound inositol in its membrane-anchoring domain. In the electromotor system of the mature fish, PIPLC solubilizes almost quantitatively the AChE dimer in the electromotor axon as in the electric organ itself, but the corresponding fraction in the electric lobe is almost totally resistant to the phospholipase. This finding implies that the covalently bound phosphatidylinositol is added concomitantly with axonal transport. A substantial part of the G2 form in back muscle is sensitive to PIPLC, whereas the G4 tetramer of Torpedo brain is completely resistant.

Acetylcholinesterase↗