The incorporation of 5-iodo-2'-deoxyuridine into the DNA of HeLa cells and the induction of alkaline phosphatase activity.

Inhibition of DNA synthesis during the period of exposure of HeLa cells to 5-iodo-2'-deoxyuridine (IUdR) inhibited the induction of alkaline phosphatase activity. This finding, taken together with previous findings that IUdR did not induce alkaline phosphatase activity in the presence of 2-fold molar excess thymidinemonstrated that IUdR incorporation into DNA is correlated with the increase in alkaline phosphatase activity. With the exception of an interim period described in the text, induction of alkaline phosphatase activity was linearly related to medium concentrations of IUdR of up to at least 3 muM. However, the extent of IUdR substitution in DNA did not appear to be related to the degree of enzyme induction. Alkaline phosphatase activity continued to increase at medium concentrations of IUdR from 1 to 3 muM, while little further substitution of DNA occurred.

Nursing documentation in the computer-based patient record.

This paper describes the INFORMM NIS (Information Network for On-line Retrieval & Medical Management Nursing Information System) charting system developed by the Departments of Nursing and Information Systems at the University of Iowa Hospitals and Clinics (UIHC). The documentation system features automated work lists, defaulted charting responses, decision support, automatic computations, chart forms and reports, and graphical displays of clinical data. The impact of the on-line charting system has been demonstrated by content standardization with Nursing Interventions Classification (NIC), improved standards compliance, increased efficiency, enhanced timeliness, expanded accessibility, and an augmented data archive.

Production of a uniform cellular injury by raster scanning of cells for the study of laser bioeffects.

Efforts to understand laser bioeffects in cells and tissues have been hindered by a nonuniform cellular response of the specimen, resulting in graded biochemical effects. In addition, the small beam diameters of commonly used lasers limit the number of cells expressing a response to numbers inadequate for the study of biochemical effects. For a limited emission power, expansion of the beam diameter reduces the irradiance, thus requiring longer exposure durations to produce a cellular response. Cultured human retinal epithelial cells were exposed as a single spot ("tophat" exposure) from a carbon dioxide (CO(2)) laser operating at 10.6 microm or scanned with a raster system and compared with thermal injury produced with heated saline for short periods (1-9 s) at relatively high temperature (55-70 degrees C). Cell viability and induction of the 70 kDa heat shock protein were evaluated as indicators of the cellular response. Initial attempts to use a tophat (uniform energy distribution) exposure resulted in a nonuniform cellular response (and nonuniform energy distribution) due to diffraction effects from the 2-mm selection aperture. However, raster scanning for appropriate times with the CO(2) laser yielded uniform cell viability and heat shock protein synthesis that were comparable to dipping cells in heated saline. Because scanning results in a homogeneous exposure of cells, the described scanning technique may be applied to studies of cellular responses to other lasers to evaluate photochemical and photomechanical effects.

Tracking vaccine compliance in a primary care setting: online history, reminders, order entry, and charting.

In a new primary care setting with three medical disciplines participating, a vaccine history and order entry system was implemented along with other online documentation systems as the primary documentation tools for the clinic. Reminders were generated based upon a set of algorithms consistent with 1998 nationally accepted vaccine guidelines. Vaccine compliance data were analyzed for the entire population cared for in this setting for a 6 month period. Rates of compliance with national recommendations for eight key vaccine groups were calculated based on the online data. Trends in the rates of compliance, interpreted within limitations, showed statistically and clinically significant improvements. The immunization application accomplished several goals: accurate history and patient-specific recommendations, online ordering of vaccines or serum products, online charting of administration that, in turn, automatically maintained the vaccine history.

Cooperative assembly of signal recognition particle RNA with protein SRP19.

Signal recognition particle (SRP) is a ribonucleoprotein complex involved in the targeting of secretory proteins to the lipid bilayer of the endoplasmic reticulum. SRP contains the protein SRP19, which is an important structural and functional component, believed to promote the assembly of the particle. We have purified the human SRP19 protein to homogeneity from recombinant bacteria which overexpress the polypeptide, and have studied details of the binding to SRP RNA via gel mobility shift and RNase sensitivity assays. SRP19 interacts with two SRP RNA conformers with different affinities such that the more compact RNA species is bound more avidly. Furthermore, binding was found to be highly cooperative. Binding constants and Hill coefficients were determined for several mutant SRP RNAs in which individual RNA helices were deleted. These results confirmed that both SRP RNA helices 6 and 8 are important for SRP19 binding. Enzymatic RNA structure probing of a 150-nucleotide mutant SRP RNA fragment and of the corresponding RNA-SRP19 complex showed that cooperativity may be due to protein-induced conformational changes in the large domain of the SRP RNA. Finally, SRP19 bound specifically not only to SRP RNA but also to the A-form of Escherichia coli 5S ribosomal RNA, thereby indicating structural similarities between these two RNA molecules.

Identification of an RNA-binding-loop in the N-terminal region of signal-recognition-particle protein SRP19.

Protein SRP19 is a 144-amino-acid polypeptide that associates intimately with the signal-recognition particle RNA (SRP RNA) and serves as an important structural and functional component of the SRP. We investigated the structure and RNA-binding activity of the human SRP19 protein by the use of comparative sequence analysis, high-stringency structure prediction, proteolytic susceptibility, and site-directed mutagenesis. SRP19 was found to consist of two distinct regions (called N-terminal and C-terminal regions) that are separated by a boundary of approximately 12-15 amino acid residues. Both regions contain an alpha-helix and several beta-strands that are connected by loops or turns. In agreement with the hypothetical model, proteolytic susceptibility demonstrated the predominant accessibility of two sites: one in a surface loop of the N-terminal region (YLNNKKTIAEGR33), and another site in the C-terminal tail at residues L129 and E133. The RNA-binding activities of mutant polypeptides with changes of conserved lysines and arginines (mutants K27Q, R33Q and R34Q) demonstrated that the proteolytically accessible loop of the N-terminal region is in direct contact with the SRP RNA. In contrast, alteration of a certain basic amino acid residues in the C-terminal region (R83, K116 and R118), as well as a deletion of four amino acid residues located at the boundary between the two regions, had no effect on the RNA-binding ability. The structural model that emerges from our data is thematically similar to that of ribosomal protein S5, the N-domain of which contains a loop motif believed to interact with double-stranded RNA. The presence of a similar structural feature in protein SRP19 has significant implications for the structure and function of the SRP19-RNA complex.

Evaluation of online documentation.

The University of Iowa Hospitals and Clinics (UIHC) implemented an online documentation system for patient care orders in 1994-1996. Developed entirely in-house, the INFORMM NIS (Information Network for Online Retrieval & Medical Management Nursing Information System) features order-generated task lists, defaulted charting responses, computer-generated chart forms, and graphical data displays. To measure the impact of automation on user perceptions, and documentation compliance, completeness, time, and location, a team of nursing and information systems representatives captured data before and after implementation. Staff surveys show more positive user perceptions. Documentation results indicate increased compliance and completeness, and a decrease or no change in time. Online documentation occurs mainly at unit workstations.