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At least 343 records · Page 19Linked to original sources
PubMed2003

The signal recognition particle binds to protein L23 at the peptide exit of the Escherichia coli ribosome.

The signal recognition particle (SRP) from Escherichia coli, composed of Ffh protein and 4.5S RNA, mediates membrane targeting of translating ribosomes displaying a signal or signal-anchor sequence. SRP binds at the peptide exit of the large ribosomal subunit. Structural details of the interaction are not known. Here, the position of Ffh or SRP on the ribosome was probed by using site-specific UV-induced crosslinking by p-azidophenacyl bromide (AzP) attached to a number of cysteine residues engineered into surface positions of Ffh. Efficient crosslinking to vacant ribosomes took place from two positions (AzP17 and AzP25) in the N domain of Ffh, both with Ffh and SRP. Both AzP17 and AzP25 were predominantly crosslinked to ribosomal protein L23 that is located at the peptide exit of the 50S subunit. The SRP receptor, FtsY, did not change the crosslink pattern, whereas the presence of a nascent signal peptide on the ribosome resulted in a second crosslink between Ffh(AzP17) and protein L23, indicating that binding to the nascent signal peptide induced a slightly different arrangement of SRP on the ribosome. These results indicate a model of the topographical arrangement of SRP at the peptide exit of the 50S ribosomal subunit.

Bacterial Proteins↗
PubMed2005

Microlens-array-based exit-pupil expander for full-color displays.

Two-dimensional arrays of microlenses can be used in wearable display applications as numerical aperture expanders or exit-pupil expanders (EPEs) to increase the size of the display exit pupil. A novel EPE approach that uses two microlens arrays (MLAs) is presented. The approach is based on cascading two identical microlens arrays spaced precisely at one focal-length distance with submicrometer registration tolerances relative to each other. The ideal MLA for this application requires a 100% fillfactor, sharp seams between microlenses, and a perfect spherical profile. We demonstrate a dual-MLA-based EPE that produces excellent exit-pupil uniformity and better than 90% diffraction efficiency for all three wavelengths in a color-display system. Two-MLA registration is performed with submicrometer precision by use of far-field alignment techniques. Fourier optics theory is used to derive the analytical formulas, and physical optics beam propagation is used for numerical computations. Three MLA fabrication technologies, including gray-scale lithography, photoresist reflow, and isotropic etching, are evaluated and compared for an EPE application.

Color↗
PubMed2005

Exit of Plasmodium sporozoites from oocysts is an active process that involves the circumsporozoite protein.

Plasmodium sporozoites develop within oocysts residing in the mosquito midgut. Mature sporozoites exit the oocysts, enter the hemolymph, and invade the salivary glands. The circumsporozoite (CS) protein is the major surface protein of salivary gland and oocyst sporozoites. It is also found on the oocyst plasma membrane and on the inner surface of the oocyst capsule. CS protein contains a conserved motif of positively charged amino acids: region II-plus, which has been implicated in the initial stages of sporozoite invasion of hepatocytes. We investigated the function of region II-plus by generating mutant parasites in which the region had been substituted with alanines. Mutant parasites produced normal numbers of sporozoites in the oocysts, but the sporozoites were unable to exit the oocysts. In in vitro as well, there was a profound delay, upon trypsin treatment, in the release of mutant sporozoites from oocysts. We conclude that the exit of sporozoites from oocysts is an active process that involves the region II-plus of CS protein. In addition, the mutant sporozoites were not infective to young rats. These findings provide a new target for developing reagents that interfere with the transmission of malaria.

Journal Article↗
PubMed2005

Migration from a mitogenic niche promotes cell-cycle exit.

During development, neural precursors proliferate in one location and migrate to the residence of their mature function. The transition from a proliferative stage to a migratory stage is a critical juncture; errors in this process may result in tumor formation, mental retardation, or epilepsy. This transition could be the result of a simple sequential process in which precursors exit the cell cycle and then begin to migrate or a dynamically regulated process in which migration away from a mitogenic niche induces precursors to exit the cell cycle. Here, we show, using in vivo and in vitro approaches, that granule cell precursors proliferate when they are exposed to the microenvironment of the external granule cell layer (EGL) and exit the cell cycle as a result of migrating away from this environment. In vivo, granule cell precursors that remain in the EGL because of impaired migration continue to proliferate in the mitogenic niche of the EGL. In vitro, granule cell precursors that are introduced into an organotypic cerebellar slice proliferate preferentially in the EGL. We identify Sonic Hedgehog as a critical component of the EGL mitogenic niche. Together, these data indicate that migration away from a mitogenic niche promotes transition from a proliferative to a nonproliferative, migratory stage.

Animals↗
PubMed2004

The identification of Pcl1-interacting proteins that genetically interact with Cla4 may indicate a link between G1 progression and mitotic exit.

In budding yeast, Cla4 and Ste20, two p21-activated kinases, contribute to numerous morphogenetic processes. Loss of Ste20 or Cla4 individually confers distinct phenotypes, implying that they regulate different processes. However, loss of both proteins is lethal, suggesting some functional overlap. To explore the role(s) of Cla4, we and others have sought mutations that are lethal in a cla4 Delta strain. These mutations define >60 genes. Recently, both Ste20 and Cla4 have been implicated in mitotic exit. Here, we identify a genetic interaction between PHO85, which encodes a cyclin-dependent kinase, and CLA4. We further show that the Pho85-coupled G(1) cyclins Pcl1 and Pcl2 contribute to this Pho85 role. We performed a two-hybrid screen with Pcl1. Three Pcl1-interacting proteins were identified: Ncp1, Hms1, and a novel ATPase dubbed Epa1. Each of these proteins interacts with Pcl1 in GST pull-down experiments and is specifically phosphorylated by Pcl1.Pho85 complexes. NCP1, HMS1, and EPA1 also genetically interact with CLA4. Like Cla4, the proteins Hms1, Ncp1, and Pho85 appear to affect mitotic exit, a conclusion that follows from the mislocalization of Cdc14, a key mitotic regulator, in strains lacking these proteins. We propose a model in which the G(1) Pcl1.Pho85 complex regulates mitotic exit machinery.

Amino Acid Sequence↗
PubMed2001

Effect of permethrin-impregnated nets on exiting behavior, blood feeding success, and time of feeding of malaria mosquitoes (Diptera: Culicidae) in western Kenya.

The impact of permethrin-treated bednets on the feeding and house entering/exiting behavior of malaria vectors was assessed in two studies in western Kenya. In one study, matched pairs of houses were allocated randomly to receive bednets or no bednets. Exiting mosquitoes were collected in Colombian curtains hung around half of each house; indoor resting mosquitoes were collected by pyrethrum spray catches. The number of Anopheles gambiae Giles and An. arabiensis Patton estimated to have entered the houses was unaffected by the presence of bednets; Anopheles funestus Giles was less likely to enter a house if bednets were present. Anopheles gambiae and An. funestus were less likely to obtain a blood meal and significantly more likely to exit houses when bednets were present. No difference was detected in An. arabiensis rates of blood feeding and exiting. In a second experiment, hourly night biting collections were done on 13 nights during the rainy season to assess whether village-wide use of permethrin-treated bednets caused a shift in the time of biting of malaria vectors. A statistically significant shift was detected in the biting times of An. gambiae s.l., although the observed differences were small. No change was observed in the hourly distribution of An. funestus biting. Our study demonstrated that, at least in the short-term, bednets reduced human-vector contact and blood feeding success but did not lead to changes in the biting times of the malaria vectors in western Kenya.

Animals↗
PubMed1991

Teaching adults with severe and profound retardation to exit their homes upon hearing the fire alarm.

Prompting, modeling, and differential reinforcement with client-chosen rewards were used to teach 3 nonverbal people with severe to profound mental retardation to exit their group homes at the sound of the house fire alarm, using a multiple baseline design. All 3 participants learned to exit independently in less than 2 min in all experimenter-initiated surprise fire drills and in the majority of staff-initiated surprise fire drills. Each participant was also able to exit from five areas of the house from which teaching was not done.

Adult↗
PubMed2006

Technical note: Exit velocity as a measure of cattle temperament is repeatable and associated with serum concentration of cortisol in Brahman bulls.

The objectives of this study were 1) to compare temperament assessments, using multiple techniques and over repeated observations, to gauge temperament over the long-term and 2) to evaluate the relationship of the temperament appraisals with serum concentrations of cortisol (CS). Measures of temperament were gathered over 3 repeated observations (60-d interval) of yearling, fall-born Brahman bulls (initial BW = 320 +/- 4 kg; n = 66). Temperament assessments included exit velocity (EV), which was the rate at which the bulls exited the squeeze chute and traversed a fixed distance (1.83 m); pen scores (PEN; 1 = quiet to 5 = excited), ascertained from animal behavior while penned in small groups (n = 5); and chute scores (CHUTE; 1 = quiet to 5 = excited), determined from behavioral responses to restraint on the weigh scale. Temperament measures obtained during the initial data collection (d 0) were all positively correlated (r > or = 0.35, P < 0.005) with one another. Additionally, PEN (r = 0.29, P < 0.05) and EV (r = 0.26, P < 0.05) were positively correlated with CS, whereas CHUTE was not (r = 0.09, P = 0.46). All serial EV measures were positively correlated (r > 0.31, P < 0.02). All PEN were positively correlated (r > 0.31, P < 0.01), whereas serial measures of CHUTE were not (P > 0.3). Exit velocity was positively correlated with CS within d 0 (r = 0.26, P = 0.04) and 120 (r = 0.44, P < 0.01). The EV data obtained at d 0 were transformed into a discrete variable, EV ranking (EV RANK; 1 to 3 scale), in which 1 equated to <1 SD below the mean and 3 equated to >1 SD above the mean. Mean EV (P < 0.01) decreased from d 0 (2.82 +/- 0.07 m/sec) to 120 (2.11 +/- 0.10 m/sec). Time also influenced (P < 0.01) CS; mean CS decreased between d 0 (14.6 +/- 0.7 ng/mL) and 120 (11.1 +/- 0.8 ng/mL). Measures of EV can be a valuable tool for the assessment of cattle temperament and a possible predictor of temperament and stress responsiveness to future animal handling events.

Animal Husbandry↗
PubMed2003

Regulation of CDC14: pathways and checkpoints of mitotic exit.

Progression of the mitotic cell cycle is driven by fluctuations of the cyclin-dependent kinase (Cdk) activities. Entry into mitosis is promoted by the elevated activity of Cdk1 associated with B-type cyclins. Conversely, exit from mitosis requires the inactivation of Cdk1 and the dephosphorylation of at least a subset of Cdk1 substrates. The Cdc14 family of phosphatases antagonizes the action of Cdk1, and is thus a major player in controlling the mitotic exit. We review recent discoveries in several model systems that have shed light on the function of Cdc14 and propose a general framework within which Cdc14 plays conserved roles in regulating the exit from mitosis and cytokinesis.

Cell Cycle↗
PubMedDate not supplied

The effect of exit-interview patient education on no-show rates at a family practice residency clinic.

BACKGROUND: Residency clinics with high no-show rates experience negative ramifications in patient health care, continuity, clinic productivity, and learning experiences for residents. This study tested patient education in the form of an exit interview to reduce no-show rates. METHODS: All eligible new patients at St. Mary's Family Practice Center between 1 February 1996 and 30 April 1997 were offered study enrollment. Patients with initial appointments during 5 of 9 clinic sessions were offered an exit interview with visit debriefing, written patient information where appropriate, and review of clinic policies. Missed patients or those with initial appointments during the remaining 4 sessions formed the control group. Interviewers were social work, medical, and nursing students. Insurance and subsequent appointment data were obtained from billing records. Median household income of ZIP codes in which patients resided was obtained from the 1990 Federal Census data. Data were analyzed using chi(2) tests, Wilcoxon rank-sum tests, and logistic regression. RESULTS: One hundred forty-six patients were enrolled into the intervention and 297 into the control group. Simple logistic regression showed a significant reduction in the risk of no-shows in the intervention group (odds ratio = 0.71, P =.04). CONCLUSIONS: The exit interview improved attendance at subsequent visits.

Adolescent↗
PubMed2003

Posterolateral percutaneous endoscopic lumbar foraminotomy for L5-S1 foraminal or lateral exit zone stenosis. Technical note.

The purpose of this study was to determine the efficacy and feasibility of posterolateral percutaneous endoscopic lumbar foraminotomy (PELF) for foraminal or lateral exit zone stenosis of the L5-S1 level in the awake patient. Twelve consecutive patients with L5-S1 foraminal stenosis and associated leg pain underwent PELF between May 2001 and July 2002. Under fluoroscopic guidance, posterolateral endoscopic foraminal decompression was performed using a bone reamer, endoscopic forceps, and a laser. Using this new technique, the authors removed part of the hypertrophied superior facet, thickened ligamentum flavum, and protruded disc compressing the exiting (L-5) nerve root. Clinical outcome was measured using the Macnab criteria. The mean follow-up period was 12.9 months. All the patients were discharged within 24 hours. Satisfactory (excellent or good) results were demonstrated in 10 patients. There was no complication. The PELF procedure provides a simple alternative for treating lumbar foraminal or lateral exit zone stenosis in selected cases. The authors found that the posterolateral endoscopic approach to the L5-S1 foramen was usually possible and that using a bone reamer to undercut the superior facet was effective.

Adult↗
PubMedDate not supplied

Complexity of mitotic exit.

Completion of mitosis in budding yeast is triggered by activation of the protein phosphatase Cdc14, which is the ultimate effector of a signalling cascade, known as the mitotic exit network. Cdc14 activation leads to eradication of mitotic kinase activity, which is pivotal for mitotic exit and cytokinesis in all eukaryotes. The complexity in mitotic exit regulation is underscored by the recent discovery of a novel network, the so-called FEAR pathway that regulates early Cdc14 activation. Surprisingly, this has revealed an unexpected role for Spo12, a protein involved in meiosis, in Cdc14 activation. In this review, we will discuss these findings together with recent advances in deciphering the function of the FEAR circuit, which has unravelled an exciting new side of Cdc14.

Anaphase↗
PubMed2003

'The ones that got away': implementing an exit policy for nurses in a public hospital.

The shortage of registered nurses in Victoria led a Melbourne metropolitan hospital to analyse their recent staff attrition rate. This analysis highlighted the importance of having an exiting policy in place for all departing staff. An exit policy can provide unique opportunities for hospitals to collect information that may help reduce future employee turnover through the identification of the causes of employee dissatisfaction. This paper will discuss the literature and outline the project that aided in the analysis of the hospital's attrition rate and development of a practical exit policy.

Attitude of Health Personnel↗
PubMed1995

Evaluating nurse turnover: comparing attitude surveys and exit interviews.

High turnover rates among hospital nurses demand rigorous and valid processes of research to determine the reasons motivating such attrition. In most hospitals, the exit interview often provides the only relevant data. The case study reported here examines the relative effectiveness of exit interviews and an employee attitude survey in generating data that are useful in managing nurse retention. The conclusion reached is that the attitude survey generates more data and higher-quality data. Further, the study shows that the use of open-ended questions can provide useful information and probably should be the starting point in developing or supplementing an attitude survey for nurses. Recommendations for improving the usefulness and validity of nurse attitude surveys and exit interviews in managing nurse retention are provided.

Attitude of Health Personnel↗
PubMedDate not supplied

The status of older adolescents at exit from out-of-home care.

Administrative data and case record reviews were used to assess the exit status of a sample of older youths leaving out-of-home care in one midwestern state. Results show that most left without a job or a high school diploma, and that many left with neither. The most common living arrangement at the time of exit was with relatives, some through planned reunification and some through unplanned reunification. The majority of the youths exited out-of-home care in unplanned ways. The number of placements and the completion of high school predicted employment status. High school completion was associated with age and a history of inpatient psychiatric care, running away, and mental retardation. Implications for independent living programs for older youths are discussed.

Adolescent↗
PubMedDate not supplied

"A change for the better". A nursing innovation for change in the CAPD catheter exit site care.

The need for change was identified when an increase occurred in peritoneal catheter exit site infection rate of those patients who had newly inserted peritoneal dialysis catheters. A decision was taken to improve this situation by reviewing the prevailing procedure. A literature search of the recommended care of peritoneal dialysis catheter exit sites was carried out; a new procedure was written in accordance with the research recommendations, as a result of the new procedure of care the exit site infections rate dropped dramatically.

Bandages↗
PubMed1999

Entry or exit? A transition-probability approach to explaining the high prevalence of single motherhood among black women.

I analyze the prevalence of single motherhood among black and non-Hispanic white women in terms of differences in entry and exit. Higher initial entry rates among black women, especially through unpartnered childbearing, account for slightly more than half the difference between blacks and whites in the prevalence of single motherhood. The remainder of the difference is due to black single mothers' much lower rates of exit through union formation and to their very high rates of reentry through dissolution of these later unions. Entry and exit rates through the 1990s imply a widening racial gap.

Adolescent↗
PubMed1999

Exit-site and catheter care: review of important issues.

This brief review addresses the impact that several important aspects of catheter technology and exit-site care have on catheter-related infections and catheter longevity. The discussion includes exit-site microbiology, catheter configuration, exit-site care, and catheter salvage, following which a summary of recommendations is presented.

Catheters, Indwelling↗