[Mechanism of tRNA translocation on the ribosome]. / Mekhanizm translokatsii tRNK na ribosome.

During the translocation step of the elongation cycle of peptide synthesis two tRNAs together with the mRNA move synchronously and rapidly on the ribosome. Translocation is catalyzed by the elongation factor G (EF-G) and requires GTP hydrolysis. The fundamental biochemical features of the process were worked out in the 1970-80s, to a large part by A.S. Spirin and his colleagues. Recent results from pre-steady-state kinetic analysis and cryoelectron microscopy suggest that translocation is a multistep dynamic process that entails large-scale structural rearrangements of both ribosome and EF-G. Kinetic and thermodynamic data, together with the structural information on the conformational changes of the ribosome and of EF-G, provide a detailed mechanistic model of translocation and suggest a mechanism of translocation catalysis by EF-G.

Stimulation of the GTPase activity of translation elongation factor G by ribosomal protein L7/12.

Elongation factors (EFs) Tu and G are GTPases that have important functions in protein synthesis. The low intrinsic GTPase activity of both factors is strongly stimulated on the ribosome by unknown mechanisms. Here we report that isolated ribosomal protein L7/12 strongly stimulates GTP hydrolysis by EF-G, but not by EF-Tu, indicating a major contribution of L7/12 to GTPase activation of EF-G on the ribosome. The effect is due to the acceleration of the catalytic step because the rate of GDP-GTP exchange on EF-G, as measured by rapid kinetics, is much faster than the steady-state GTPase rate. The unique, highly conserved arginine residue in the C-terminal domain of L7/12 is not essential for the activation, excluding an "arginine finger"-type mechanism. L7/12 appears to function by stabilizing the GTPase transition state of EF-G.

Nurses perspective of patient acuity on geriatric assessment units.

The purpose of this study was to explore how nurses on geriatric assessment inpatient units perceived patient acuity. Three questions were developed and included: what variables do nurses use to define acuity; does variation exist between and among groups of nurses; and are there nursing activities taken for granted or overlooked that can contribute to the perception of acuity? The purposive sample included all the full time and part time nurses (11 RNs, 16 LPNs) working on the units. Focus groups were used to facilitate the data gathering for this qualitative study. Five themes were identified from the data and the program NUD*IST was used to visualize the relationships between the individual items and themes. Patient acuity was defined differently by the RNs and LPNs and is based on their reality and the realm of their mandated practice. A large category of indirect non patient related activities was found to contribute greatly to the nurses' perception of acuity. Two benefits of the study were: 1) provision of a breakdown of items nurses incorporate into their definition of acuity; 2) a list of categories to guide decision making when determining which category of staff is required to best meet the needs of the patients.

Patient requirements for nursing care: the development of an instrument.

The determination of nursing staff mix is a challenge for many health care agencies. Staff mix decisions have historically been based on workload measurement information, the type of patient care unit and on a subjective or intuitive basis. Weighted task lists (workload measurement systems) do not comprehensively consider the skill and knowledge level required to meet patient care needs. This project describes the development of an instrument that considers patient's nursing care needs as a determinant of nursing staff mix. Recommendations for the use of the tool are identified.

Evaluating the psychosocial component of nursing care in a geriatric program.

Today, most health care programs must operate within a framework of: 1) competing demands for resources, 2) pressure to reduce staffing levels, and 3) consumer demands for high quality service. Competing demands for resources means that there is a need to continuously justify a program by providing critical evaluations of program components and identifying effective outcome measures. Within a geriatric psychiatry program that provides assessment and short term treatment, various evaluation measures were tried. While none of the measurement techniques was completely satisfactory, it became very apparent that the psychosocial nursing skills that were critical in the care of this population were not accounted for by any of the current tools. Given the need to justify the high ratio of RN staffing to other categories, eg. CCA or LPN, two measures specific to nursing were tried on a pilot basis. This paper reports on the initial measurement techniques used and the results from the trial of new measures.

Admission criteria for a special care unit for residents with dementia.

The recent trend in caregiving for cognitively impaired residents has been to provide special care units. One of the questions in establishing a special unit is deciding on admission criteria. What range of impairment will benefit the most from this type of environment? This paper reports on how one facility developed specific assessment criteria for admission to a special unit. The goals were to identify potential residents for the unit, reduce subjectivity in the assessment process and be able to screen both residents and community applicants. Results of the screening instrument demonstrated that it was effective in identifying a range of impairments, it screened out the cognitively well and long standing psychiatric disorders, and also demonstrated that a pre-set bias did exist as to who should be admitted.