Curbside consultation for the nurse practitioner: Qualitative inquiry for education, policy, and practice

Curbside Consultation is a multidimensional process used by nurse practitioners for clinical decision-making in multiple settings. Given that Curbside Consultation is a highly utilized resource among nurse practitioners, further understanding of processes utilized for Curbside Consultation among nurse practitioners is critical for application to nurse practitioner practice, policy, and education

Identification of three prominin homologs and characterization of their messenger RNA expression in Xenopus laevis tissues

Purpose Prominin is a family of pentaspan transmembrane glycoproteins. They are expressed in various types of cells, including many stem/progenitor cells. Prominin-1 plays an important role in generating and maintaining the structure of the photoreceptors. In this study, we identified three prominin homologs in Xenopus laevis, a model animal widely used in vision research, and characterized their messenger RNA (mRNA) expression in selected tissues of this frog. Methods Reverse-transcription PCR (RT–PCR) and rapid amplification of cDNA ends (RACE) were used to isolate cDNAs of prominin homologs. Semiquantitative RT–PCR was used to measure the relative expression levels of mRNAs of the three prominin homologs in four X. laevis tissues, specifically those of the retina, brain, testis, and kidney. Sequences of prominin homologs were analyzed with bioinformatic software. Results We isolated cDNAs of three prominin homologs from X. laevis tissues and compared their sequences with previously described prominin-1, 2, and 3 sequences from other species using phylogenetic analysis. Two of these homologs are likely to be the X. laevis orthologs of mammalian prominin-1 and 2, respectively, while the third homolog is likely to be the X. laevis ortholog of prominin-3, which was only found in nonmammalian vertebrates and the platypus. We identified alternatively spliced exons in mRNAs of all three prominin homologs. Similar to mammalian prominin-1, we found that exons 26b, 27, and 28a of the X. laevis prominin-1 gene are alternatively spliced, and that the splice isoforms of mRNA show tissue-specific expression profiles. We found that prominin-1 was the most abundant homolog expressed in the retina, brain, and testis, while prominin-3 was the most abundant homolog in the kidney. The expression level of prominin-2 was the lowest of the three prominin homologs in all four examined tissues of this frog. Conclusions Our results suggest that the mRNAs of prominin homologs are expressed in many tissues of X. laevis, but differ in their expression levels and mRNA splicing. Prominin-1 is the most abundant of the three prominin homologs expressed in the frog retina

Greasing the protein biosynthesis machinery of photoreceptor neurons: Role for postprenylation processing of proteins

Daily phagocytosis of outer segments (OS) places extraordinary demands on protein biosynthesis and trafficking in photoreceptor neurons. While the members and roles of the phototransduction pathway in the OS are well characterized, details about protein trafficking are just beginning to emerge. Phosphodiesterase6 (PDE6), the effector enzyme in phototransduction cascade, serves as an example of the steps multimeric proteins must pass through to achieve their functional state in the OS. Genetic model systems have recently provided snapshots of various steps in the pathway, as experimental difficulties such as an inability to maintain ciliated photoreceptor outer segments or express functional PDE6 holoenzyme in vitro necessitate in vivo studies. We will highlight the significant findings, their implications to blinding diseases, as well as discuss the gaps requiring further investigation

THE ROLE OF THE THYMUS IN DEVELOPMENT OF IMMUNOLOGIC CAPACITY IN RABBITS AND MICE

In rabbits, complete thymectomy before the age of 5 days produced immunologic deficiency in the adult animals, as indicated by reduced antibody production to bovine serum albumin and bacteriophage T2. Homotransplantation immunity was unaffected, however. In an inbred strain of mice, complete neonatal thymectomy resulted in complete inability of the 60-day-old animals to form antibody to bacteriophage T2. Inbred mice, completely thymectomized at birth, had a deficient homograft response, indicated by acceptance of skin homografts from strains differing in both the weaker and stronger (H-2) histocompatibility antigens. Tumor transplants (mammary adenocarcinoma) were also successful across the H-2 genetic barrier in mice thymectomized at birth. Neonatal thymectomy also eliminated the Eichwald-Silmser phenomenon, rendering female mice capable of accepting isografts of male skin. Transplantation immunity in mice was also affected by later thymectomy, at 30 days of age, in certain strain combinations involving weak histocompatibility differences. Spleen and lymph node cells from mice thymectomized at birth or at 6 days of age, and sacrificed 2 months later, did not produce a graft versus host reaction in appropriate F1 hybrid recipients, indicating that such cells are immunologically inactive. Neonatal thymectomy of F1 hybrid mice, and in one strain combination thymectomy at 40 days of age, produced animals with inordinate susceptibility to runt disease (homologous disease) following injection of parent strain spleen cells 35 days (neonatal surgery) and 10 days (surgery at 40 days) later. Mice thymectomized at birth also showed growth failure and were short-lived. Studies of newborn mice indicated that they have true lymphocytes only in the thymus, and lack such cells in the spleen, lymph nodes, and gut. In normal mice, adult lymphoid structure develops gradually, beginning during the 1st week of life and continuing for the next month. In contrast, mice thymectomized at birth do not develop mature lymphoid structure: the lymph nodes and spleens tend to be small and poorly organized, and show a quantitative deficiency in lymphoid cells. It is our current working hypothesis that the thymus makes a major contribution toward the centrifugal distribution of lymphoid cells which, in turn, is essential to the full expression of immunologic capacity