Biomedical subjects

Robert Levenson

Publications and source records attributed to Robert Levenson.

24 records · Page 2Linked to original sources

PubMed2002

Cloning, mapping, and developmental expression of a sixth zebrafish Na,K-ATPase alpha1 subunit gene (atp1a1a.5).

We have identified and characterized cDNAs encoding a novel zebrafish Na,K-ATPase alpha subunit. The full-length cDNA encodes a 1,023-amino-acid-long peptide which shows greatest homology to zebrafish alpha1 polypeptides. Radiation hybrid mapping localized the new gene (atp1a1a.5) to linkage group 1 in close proximity to the previously identified cluster of Na,K-ATPase alpha1 genes. The expression of atp1a1a.5 in zebrafish embryos was analyzed using whole-mount in situ hybridization. From mid-somitogenesis through 48 h post fertilization (hpf), atp1a1a.5 transcripts were detected in the pronephric duct, ear, and mucous cells. This expression pattern continues through 108 hpf, when high levels of expression were also detected in the intestinal bulb.

Animals↗

PubMed2002

Cloning, mapping, and developmental expression of a sixth zebrafish Na,K-ATPase alpha1 subunit gene (atp1a1a.5).

We have identified and characterized cDNAs encoding a novel zebrafish Na,K-ATPase alpha subunit. The full-length cDNA encodes a 1023-amino-acid-long peptide which shows greatest homology to zebrafish alpha1 polypeptides. Radiation hybrid mapping localized the new gene (atp1a1a.5) to linkage group 1 in close proximity to the previously identified cluster of Na,K-ATPase alpha1 genes. The expression of atp1a1a.5 in zebrafish embryos was analyzed using whole-mount in situ hybridization. From mid-somitogenesis through 48 h post fertilization (hpf), atp1a1a.5 transcripts were detected in the pronephric duct, ear, and mucous cells. This expression pattern continues through 108 hpf, when high levels of expression were also detected in the intestinal bulb.

Amino Acid Sequence↗

PubMed2002

D2 and D3 dopamine receptor cell surface localization mediated by interaction with protein 4.1N.

We identified protein 4.1N as a D2-like dopamine receptor-interacting protein in a yeast two-hybrid screen. Protein 4.1N is a neuronally enriched member of the 4.1 family of cytoskeletal proteins, which also includes protein 4.1R of erythrocytes and the 4.1G and 4.1B isoforms. The interaction of protein 4.1N was specific for the D2 and D3 dopamine receptors and was independently confirmed in pulldown and coimmunoprecipitation assays. Deletion mapping localized the site of dopamine receptor/protein 4.1N interaction to the N-terminal segment of the third intracellular domain of D2 and D3 receptors and the carboxyl-terminal domain of protein 4.1N. D2 and D3 receptors were also found to interact with the highly conserved carboxyl-terminal domain of proteins 4.1R, 4.1G, and 4.1B. Immunofluorescence studies show that protein 4.1N and D2 and D3 dopamine receptors are expressed at the plasma membrane of transfected human embryonic kidney 293 and mouse neuroblastoma Neuro2A cells. However, expression of D2 or D3 receptors with a protein 4.1N truncation fragment reduces the level of D2 and D3 receptor expression at the plasma membrane. These results suggest that protein 4.1N/dopamine receptor interaction is required for localization or stability of dopamine receptors at the neuronal plasma membrane.

Amino Acid Sequence↗

PubMed2002

Dominant negative mutants of filamin A block cell surface expression of the D2 dopamine receptor.

Protein interaction screens have revealed an interaction between the D2 dopamine receptor and the actin cross-linking protein filamin A. However, the physiological significance of this interaction has not been explained. To better understand the role of filamin A in D2 receptor-mediated signaling, we examined the effect of disrupting filamin A/D2 receptor interaction. Overexpression of a truncated form of filamin A (repeat units 18-19 containing the D2, but not the actin, binding domain) caused a marked reduction in both the number and half-life of cell surface D2 receptors. These results suggest that disruption of the linkage between D2 receptors and the actin cytoskeleton destabilizes plasma membrane-associated D2 receptors. Several missense mutations within repeat unit 19 of filamin A were identified that abrogate filamin A/D2 receptor interaction. Introduction of mutant and wild-type filamin A into filamin A-deficient M2 cells demonstrated that wild-type filamin A, but not the filamin A-binding mutants, was able to promote cell-surface expression of D2 receptors. Together, these studies provide evidence that filamin A/D2 receptor interaction is required for the proper targeting or stabilization of D2 dopamine receptors at the plasma membrane.

Amino Acid Sequence↗

PubMed2002

Outbreak of cyclosporiasis associated with imported raspberries, Philadelphia, Pennsylvania, 2000.

An outbreak of cyclosporiasis occurred in attendees of a wedding reception held in Philadelphia, Pennsylvania, on June 10, 2000. In a retrospective cohort study, 54 (68.4%) of the 79 interviewed guests and members of the wedding party met the case definition. The wedding cake, which had a cream filling that included raspberries, was the food item most strongly associated with illness (multivariate relative risk, 5.9; 95% confidence interval, 3.6 to 10.5). Leftover cake was positive for Cyclospora DNA by polymerase chain reaction analyses. Sequencing of the amplified fragments confirmed that the organism was Cyclospora cayetanensis. The year 2000 was the fifth year since 1995 that outbreaks of cyclosporiasis definitely or probably associated with Guatemalan raspberries have occurred in the spring in North America. Additionally, this is the second documented U.S. outbreak, and the first associated with raspberries, for which Cyclospora has been detected in the epidemiologically implicated food item.

Adolescent↗

PubMedDate not supplied

Do laws bring children in child care centers up to date for immunizations?

BACKGROUND: Pennsylvania state law requires licensed child care centers (CCCs) to document that each enrolled child is up to date (UTD) for routine immunizations within 60 days of enrollment. This study evaluates the law's impact on immunization coverage among children aged <or=59 months who attend CCCs in Philadelphia. METHODS: Out of Philadelphia's 440 commercial CCCs, 75 were randomly selected. Of these, 9 had closed, 3 did not accept children aged <or=59 months, and 3 refused assessment. For the remaining 60 CCCs, vaccination dates were abstracted from CCC records for all enrolled children <or=59 months. For children not UTD for all vaccines according to CCC records, additional data were sought from Philadelphia's immunization registry, health care providers, and parents. RESULTS: Records of 2847 children were assessed. According to CCC records, information from the immunization registry, vaccination providers, and parents, 71% of children aged 0-18 months, 77% of children 19-35 months, and 84% of children 36-59 months were UTD for their age for diphtheria, tetanus toxoids, and pertussis vaccine; polio; Haemophilus influenzae type b; and measles, mumps, and rubella vaccines. No significant increase in immunization coverage levels was found between the date children enrolled in a CCC and 60 days later. CONCLUSIONS: Up to one quarter of children <5 years of age enrolled in Philadelphia's CCCs are not UTD for immunizations, with children 0-18 months of age being most behind in their immunizations. Furthermore, many children do not receive vaccines within 60 days of enrollment. These low coverage levels combined with the potential exposures inherent in group care settings indicate that children in CCCs are at risk for contracting vaccine-preventable diseases.

Child Day Care Centers↗