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PubMedDate not supplied

The risk of infection and peritoneal catheter loss from implant procedure exit-site trauma.

OBJECTIVE: To evaluate the role of skin and subcutaneous tissue trauma at the time of catheter implant procedure as a determinant of catheter loss from infectious complications. DESIGN: Nonrandomized study with prospective collection of data. PATIENTS: Consecutive patients were divided into three groups based upon how the catheter was exited through the skin: group 1, procedure involved pulling tubing, with a permanently bonded catheter adapter, through the exit-site wound (n = 43); group 2, same as group 1 except exit wounds were closed around the catheter with a suture (n = 20); group 3, procedure involved pulling only tubing through the exit wound (n = 61). SETTING: Primary medical center for a health maintenance organization. MAIN OUTCOME MEASURES: Log rank comparisons of Kaplan-Meier analyses of first occurrences of infectious events and overall catheter survival. RESULTS: The risk of first exit-site infection (p < 0.001), tunnel infection (p < 0.001), catheter infection-related peritonitis (p < 0.001), and catheter loss (p < 0.01) were greatest in group 1 with large exit wounds, and lowest in group 3 with small exit wounds. CONCLUSIONS: The study demonstrates the importance of careful dissection and exit-site construction. The exit site should consist of the smallest hole possible that permits passage of only the tubing and leaves the skin snug around the catheter. The present report incriminates catheter designs employing permanently bonded adapters that result in large pericannular wounds that are prone to infection and catheter loss.

Catheters, Indwelling↗
PubMed1992

Erythema: does it indicate infection in a peritoneal catheter exit site?

The definition of a peritoneal catheter exit site infection varies from one dialysis center to another. A review of abnormal appearing exit sites (n = 334 in 169 patients) from 1/83 to 3/91 was done to compare outcome in exit sites presenting with erythema (39, 12%) to those with drainage plus erythema (72, 22%) or drainage alone (223, 67%). Resolution of the abnormality occurred in 48% of those exit sites with drainage, 62% with erythema and drainage, and 79% with erythema alone (p < 0.005). S. aureus was present in 62% of the cultured exit sites which had erythema alone, 64% with erythema plus drainage, and 41% with drainage alone, while Gram negative rods were present in 13%, 12%, and 35%, respectively (p < 0.005). Twenty-three of the 39 exit sites with erythema were not initially treated with antibiotics; 87% resolved compared with 69% of those treated immediately with antibiotics (p = ns). Seven of the 8 erythematous exit sites that did not resolve progressed to tunnel infection and/or peritonitis and required catheter removal, despite the addition of antibiotics in the three initially untreated. Six of the 8 unresolved erythematous exit sites were due to S. aureus. These results indicate that, although drainage is the commonest exit site abnormality and has the worst prognosis, peri-catheter erythema is not always benign, representing an early sign of infection in some cases.

Catheterization↗
PubMed1996

Exit-site study methods and results.

Contrary to peritonitis, where the clinical presentation is clearly different from that of normal, there is a spectrum of appearances from uninfected to infected exit sites. This led to imprecise definitions of exit-site infection, difficulties in interpreting the results of various studies, and many, varied treatment recommendations. We have performed 565 evaluations of 61 healed exit sites in 56 patients. The exit and the sinus were inspected using a Zeiss prism loupe with 4.5x magnification for the presence, absence, intensity, and/or characteristics of specific attributes such as swelling, color, crust, drainage, granulation tissue, and epithelium in the sinus. Pictures of the external exit and the visible sinus tract were then drawn and photographs of the exit site and visible sinus tract were taken. Visual attributes discerned by loupe inspection were verified by review of photographs. A new classification was developed with six distinct categories of exit appearances: acute infection, chronic infection, external cuff infection, equivocal, good, and perfect. Finally, the category of traumatized exit was established, because trauma may result in various appearances. The outcomes in each category were correlated with treatment measures in a 5-year longitudinal study. The validity of this classification and its applicability to clinical practice was subjected to further investigation in a cross-sectional study. Forty-five patients were evaluated only once by ZJT using a Zeiss prism loupe and by the primary nurse, who used a handheld magnifier. The features were recorded and classification was made. The results of loupe and magnifier evaluations were then compared regarding agreement in discerning features. In 41 evaluations (91%) there was agreement. The new classification may be useful in making treatment decisions, in reporting exit-site infection data, and in designing improved prospective, randomized studies.

Adult↗
PubMed1997

Automated TLD system for tumor dose estimation from exit dose measurements in external beam radiotherapy.

PURPOSE: An automated TLD facility has been commissioned and calibrated, and techniques have been developed for the measurement of exit doses in external beam radiotherapy, to enable the routine estimation of delivered tumor doses. METHODS AND MATERIALS: An automated TLD system, originally intended for use in diagnostic radiology and radiation protection, has been evaluated and configured for the measurement of exit doses in radiotherapy. Linearity, optimum heating cycles and calibration procedures have been determined. At the photon energies used, encapsulated lithium fluoride chips provide insufficient buildup to ensure electronic equilibrium, necessitating calibration to allow for oblique exit surfaces. Expressions are derived to allow the calculation of delivered tumor doses. RESULTS: Under the calibration conditions described, the uncertainty in a single TLD measurement is approximately +/-2% (+/-1 standard deviation). Over the dose range 0.4-1.5 Gy, TL response is linear. The total heating cycle time, including annealing, is 75 s. Measurements of R(exit) (the ratio of exit dose with and without full backscatter), used in the estimation of tumor doses, decreases with field size for small fields and varies only slightly for field sizes greater than 7 x 7 cm. Lack of electronic equilibrium leads to a decrease in R(exit) with increasing exit surface obliquity for all energies considered. Application of the technique to a simulated treatment showed good agreement between estimated and applied tumor doses, when surface obliquity was taken into account. CONCLUSION: This work describes the commissioning and calibration of an automated TLD facility and demonstrates that exit surface measurements using TLD chips used under conditions where electronic equilibrium was not established, have the potential for identifying discrepancies in delivered tumor doses.

Calibration↗
PubMed1997

Successful radiofrequency ablation of idiopathic left ventricular tachycardia at a site away from the tachycardia exit.

OBJECTIVES: This study sought to assess the possibility of ablating verapamil-responsive idiopathic left ventricular tachycardia at a site distant from the tachycardia exit and thus to define the tachycardia circuit. BACKGROUND: The nature of the reentry circuit in idiopathic left ventricular tachycardia is unclear. If the circuit is of considerable size, then it should be possible to ablate the tachycardia at a site distant from the exit site. METHODS: Electrophysiologic studies and radiofrequency ablation were performed in 27 consecutive patients with verapamil-responsive idiopathic left ventricular tachycardia. In all 27 patients, the tachycardia exit site was defined as the site where the earliest Purkinje potential was recorded > or = 25 ms before the onset of the QRS complex during the tachycardia and where the pace map QRS complex resembled that during the tachycardia. A potential ablation site other than the exit site was then sought around the midseptum, proximal to the exit site. At such sites the tachycardia could be terminated transiently by pressure applied to the catheter tip, without induction of ventricular ectopic beats. RESULTS: The potential ablation site, other than the tachycardia exit site, was identified in seven male patients (mean [+/-SD] age 31 +/- 12 years, range 13 to 52). Application of the radiofrequency current at this site resulted in termination of the tachycardia within 1 to 5 s (mean 2.9 +/- 1.6), and successful ablation of the tachycardia was achieved in all seven patients (success rate 100%, 95% exact confidence interval 0.5898 to 1). The mean distance between the ablation site and the tachycardia exit site was 3.1 +/- 0.7 cm (range 2.0 to 4.0). A presystolic Purkinje spike was recorded 14 +/- 5 ms (range 8 to 20) before the onset of the QRS complex during the tachycardia. During the follow-up period of 24 +/- 11 months (range 12 to 39), there was no recurrence of tachycardia in these seven patients. CONCLUSIONS: Successful ablation of idiopathic left ventricular tachycardia can be achieved at sites away from the tachycardia exit site in some patients. This finding suggests that the reentry circuit is likely to be of considerable size, encompassing the middle, inferior and lower aspects of the left interventricular septum.

Action Potentials↗
PubMed2001

Ventricular echo beats and retrograde atrioventricular nodal exits in the dog heart: multiplicity in their electrophysiologic and anatomic characteristics.

INTRODUCTION: A single ventricular echo beat frequently is induced in the dog heart by ventricular pacing, but it has not been investigated using a concomitant ablative technique. We studied the effects of ablating the anterior atrial input to the AV node on ventricular echo beats induced in the dog heart to evaluate their electrophysiologic characteristics, the anatomic reentrant circuit, and the retrograde AV nodal exits. METHODS AND RESULTS: In 20 dogs, an epicardial radiofrequency current was applied to the right anterior septum in an attempt to ablate the anterior input to the AV node. Ventricular programmed stimulation was performed to evaluate the ventricular echo beat and the retrograde AV nodal exit before and after ablation. The AV junction was examined with light microscopy. Seventeen dogs in which the PR interval was prolonged significantly from 108+/-17 msec to 153+/-19 msec (P < 0.001) were selected for ventricular echo evaluation; 3 dogs in which persistent second- or third-degree AV block was induced by ablation were excluded. Ventricular echo beats, which were induced in 13 of 17 dogs, were classified into the anterior type (n = 6) or posterior type (n = 7) according to the earliest atrial activation site during the echo beat. The retrograde AV nodal exit site showed anterior-exit only (n = 10), posterior-exit only (n = 2), and dual-exit (n = 5) patterns. After ablation, the anterior-type ventricular echo beat was noninducible in all 6 dogs, whereas the posterior-type ventricular echo beat was noninducible in only 3 of 7 dogs. In 17 dogs, VA conduction was not demonstrated after ablation in 3 dogs, all of which showed the anterior-exit only pattern. CONCLUSION: The effect of ablation on the ventricular echo beats and retrograde AV nodal exit site suggests multiplicity in their electrophysiologic and anatomic characteristics in the dog heart.

Animals↗
PubMed2004

Routine use of mupirocin at the peritoneal catheter exit site and mupirocin resistance: still low after 7 years.

OBJECTIVE: The purpose of this study (the third in a series of similar studies) is to evaluate the prevalence of Staphylococcus aureus (SA), methicillin-resistant SA (MRSA) and mupirocin-resistant SA (MuRSA) carriers in a peritoneal dialysis centre where patients have been instructed to use prophylactic mupirocin ointment at the catheter exit site over the last 7 years. METHODS: Swabs were taken from catheter exit site, nares, axillae and groin in 147 chronic peritoneal dialysis out-patients between November 2003 and January 2004. Axillae/groin and nasal samples were pooled and cultured in the same medium, whereas exit site swabs were cultured separately. All SA isolated were tested for methicillin and mupirocin resistance using oxacillin screening plates and E-test strips. RESULTS: Sixteen of 147 patients (10.9%) were found to be SA carriers: of these 13 (8.8%) had a positive nasal/axillae/groin culture; two (1.4%) had both nasal/axillae/groin- and exit site-positive culture; and one (0.7%) had only exit site-positive culture. In these 16 SA carriers, we found mupirocin-resistant strains (MuRSA) in four patients (25%) and MRSA in two patients (12.5%). Among the four MuRSA carriers, one had both nasal/axillae/groin- and exit site-positive culture and three had only nasal/axillae/groin-positive culture. Three high-level resistance and one low-level resistance MuRSA carriers were isolated. One MuRSA strain was also methicillin resistant. All MRSA strains were sensitive to vancomycin and rifampicin. CONCLUSION: After 7 years' routine use of prophylactic mupirocin ointment at the catheter exit site in non-selected chronic peritoneal dialysis patients, MuRSA was found in 25% of SA strains isolated or in 2.7% of the patients. Compared with our previous study, 3 years earlier, there is no significant increase in the MuRSA prevalence in peritoneal dialysis patients who routinely apply mupirocin ointment at the catheter exit site.

Adult↗
PubMed1973

Glutamate transport in Escherichia coli K-12: nonidentity of carriers mediating entry and exit.

The exit of glutamate from Escherichia coli K-12 cells preloaded with the radioactive amino acid and its relation to the reaction of entry were studied. Experiments with cells preloaded to different intracellular concentrations of radioactive glutamate confirmed our earlier conclusion that glutamate exit was a first-order reaction. l-Glutamate, competitive inhibitors of glutamate uptake (d-glutamate and l-glutamate-gamma-methyl ester), noncompetitive inhibitors of glutamate uptake (l-serine and l-alanine), and the energy poison NaN(3) all accelerated glutamate exit 2.8-fold. No additive effect was observed in the presence of NaN(3) together with l-glutamate. Preloading with cold l-glutamate did not increase the rate of uptake of radioactive glutamate. It is concluded that the acceleration of glutamate exit in the presence of l-glutamate in the medium is not due to exchange diffusion and that l-glutamate and azide affect exit indirectly by preventing recapture. Sucrose, 25%, slowed down glutamate exit by a factor of about 4.7 and increased the steady-state level of glutamate accumulation to about the same extent. Increasing the intracellular K(+) concentration enhanced glutamate uptake but did not affect the half-time of exit. It is concluded that separate carriers are most probably involved in mediating the entry and exit reactions.

Alanine↗
PubMed2005

Transforming growth factor beta 1 promotes cell cycle exit through the cyclin-dependent kinase inhibitor p21 in the developing cerebral cortex.

During cortical neurogenesis, cell proliferation and cell cycle exit are carefully regulated to ensure that the appropriate numbers of cells are produced. The antiproliferative agent transforming growth factor beta1 (TGFbeta1) and its receptors are endogenously expressed in proliferative zones of the developing cerebral cortex, thus implicating the growth factor in cell cycle regulation. The present study tested the hypothesis that TGFbeta1 promotes cell cycle exit in the cortical ventricular zone (VZ) through modulation of cell cycle protein expression, in particular cyclin D1 and the cyclin-dependent kinase inhibitors p27 and p21. Although it did not affect the length of the cell cycle, TGFbeta1 decreased the fraction of VZ-cycling cells by 21% and increased the number of VZ cells exiting the cell cycle a commensurate 24%. TGFbeta1 selectively increased the expression of p21 in the VZ. In addition, high p21 expression levels were observed in VZ cells as they exited the cell cycle, and TGFbeta1 increased the number p21-positive cells exiting the cell cycle. Collectively, these data show the following: (1) TGFbeta1 promotes cell cycle exit, (2) p21 upregulation is correlated with cell cycle exit, and (3) TGFbeta1-induced cell cycle exit is mediated by p21.

Animals↗
PubMed1992

Relationship between peritonitis and exit site infections in CAPD.

This study was designed to retrospectively review the experience in this center with oral ciprofloxacin 500 mg bid and ip vancomycin 25 mg/L in the treatment of CAPD-related exit site infections and to determine the relationship between exit site infections and peritonitis. There were 48 patients with 172 episodes of infection (23 had both infections, 22 had peritonitis only, 3 had exit site infections only). Thus, exit site infections occur infrequently in the absence of peritonitis (23% of occasions). Of the 35 patients who had peritonitis as the first infection, 13 (37%) subsequently developed an exit site infection. The mean +/- SD period from an initial peritonitis to a subsequent exit site infection in these patients was 8.2 +/- 8.0 (range 1-28) months. Of the 22 patients with 34 exit site infections, there were 15 (44%) treatment failures, of which 10 (67%) were relapses or possible relapses. S. aureus was the most common isolate. 5% of exit site infections were culture negative. Follow-up was incomplete for many patients resulting in many instances of no further cultures, and compliance could not be assured. This combination was associated with a high incidence of treatment failures in this setting.

Ciprofloxacin↗
PubMed1995

The impact of exit-site care and catheter design on the incidence of catheter-related infections.

The optimal approach to catheter exit-site care and catheter design in terms of catheter-related infections (e.g., exit-site infections, peritonitis) in children remains elusive. We retrospectively compared the incidence of exit-site infections and peritonitis in 33 pediatric peritoneal dialysis patients who used one of three exit-site care/catheter combinations. The catheters used were single-cuffed, curled Tenckhoff (T), and double-cuffed Swan neck (SN). Exit-site care included either povidone-iodine (PI) or chlorhexidine (CHL) as cleansing agents. Our data suggest that the use of chlorhexidine versus povidone-iodine is associated with a significant decrease (p < 0.05) in the frequency of catheter exit-site infections in children. The use of the Swan-neck double-cuffed catheter does not appear to have any further impact on the frequency of exit-site infections. Neither the use of chlorhexidine nor Swan neck catheters had an effect on our peritonitis rate. Our review suggests that a prospective evaluation of a chlorhexidine-based exit-site care regimen in children should be encouraged.

Anti-Infective Agents, Local↗
PubMed2002

A simplified approach for exit dose in vivo measurements in radiotherapy and its clinical application.

This is a study using LiF:Mg;Ti thermoluminescent dosimeter (TLD) rods in phantoms to investigate the effect of lack of backscatter on exit dose. Comparing the measured dose with anticipated dose calculated using tissue maximum ratio (TMR) or percentage depth dose (PDD) gives rise to a correction factor. This correction factor may be applied to in-vivo dosimetry results to derive true dose to a point within the patient. Measurements in a specially designed humanoid breast phantom as well as patients undergoing radiotherapy treatment were also been done. TLDs with reproducibility of within +/- 3% (1 SD) are irradiated in a series of measurements for 6 and 10 MV photon beams from a medical linear accelerator. The measured exit doses for the different phantom thickness for 6 MV beams are found to be lowered by 10.9 to 14.0% compared to the dose derived from theoretical estimation (normalized dose at dmax). The same measurements for 10 MV beams are lowered by 9.0 to 13.5%. The variations of measured exit dose for different field sizes are found to be within 2.5%. The exit doses with added backscatter material from 2 mm up to 15 cm, shows gradual increase and the saturated values agreed within 1.5% with the expected results for both beams. The measured exit doses in humanoid breast phantom as well as in the clinical trial on patients undergoing radiotherapy also agreed with the predicted results based on phantom measurements. The authors' viewpoint is that this technique provides sufficient information to design exit surface bolus to restore build down effect in cases where part of the exit surface is being considered as a target volume. It indicates that the technique could be translated for in vivo dose measurements, which may be a conspicuous step of quality assurance in clinical practice.

Breast↗
PubMed2006

Exit, voice, governance and user-responsiveness: the case of English primary care trusts.

Hirschman contrasts exit and voice as 'recuperation' mechanisms for making organisations responsive to users. However, the emergence of health-care quasi-markets and of network governance structures since Hirschman necessitate revising his theory, for they complicate the relationships between governance structures and recuperation mechanisms. Using a case study of nine primary care trusts (PCTs), this paper analyses the recuperation mechanisms, governance structures and relations between them in primary care in England. User voice can be exercised through dedicated networks besides hierarchies. As well as the 'user exit' described by Hirschman, two new 'exit' mechanisms now exist in quasi-markets. Commissioner exit occurs when a third-party payer stops using a given provider. Professional proxy exit occurs when a general practitioner (GP) fund-holder (or analogous budget-holder) behaves similarly. Neither exit mechanism requires the existence of mechanisms for user exit from healthcare purchasers, provided strong voice mechanisms exist instead to make commissioners responsive to users' demands. Establishing such voice mechanisms is not straightforward, however, as the experience of English PCTs illustrates.

Consumer Behavior↗
PubMed1987

A five-year study of the microbiologic results of exit site infections and peritonitis in continuous ambulatory peritoneal dialysis.

We studied the culture results from 321 continuous ambulatory peritoneal dialysis (CAPD) related infections (exit site, tunnel infections, and peritonitis) in 137 patients over a 5-year period to determine the contribution of exit site and tunnel infections to peritonitis and catheter loss. Seventeen percent of peritonitis episodes were associated temporally and by microbiologic results with exit site or tunnel infections. Twenty-one percent of exit site and tunnel infections and 20% of peritonitis episodes resulted in catheter loss. Peritonitis due to Staphylococcus aureus was more likely to be associated with an exit site or tunnel infection and was more likely to result in loss of the catheter than peritonitis due to Staphylococcus epidermidis. Peritonitis and exit site infections due to Pseudomonas sp also frequently resulted in catheter removal. We found that exit site infections cause significant morbidity in CAPD patients. Further studies in this area are needed.

Catheters, Indwelling↗
PubMed1996

Peritoneal catheter exit-site and tunnel infections.

Peritoneal catheter exit-site and tunnel infections may lead to peritonitis and catheter loss. Exit-site infections are diagnosed when there is pericatheter erythema and/or purulent drainage. Staphylococcus aureus is the most common cause of both exit-site and tunnel infections. S. aureus nasal carriage is an important risk factor for S. aureus catheter infections. Few other risk factors for catheter infections have been identified. Treatment of catheter infections consists of antibiotic therapy, often prolonged, as well as intensification of exit-site care. Refractory cases may resolve with revision of the tunnel and exit-site with removal of the superficial cuff, but some patients undergoing this procedure will develop peritonitis. Once peritonitis develops from a tunnel infection, the catheter should be replaced. Research on prevention of catheter infections has focused on three areas: antibiotic prophylaxis, exit-site care, and new catheter designs. Several antibiotic protocols, including intranasal mupirocin, cyclical oral rifampin, and exit-site mupirocin, are effective in decreasing S. aureus catheter infections and should be used more widely. New catheter designs may, in the future, prove to further diminish catheter infection and loss, but there are insufficient data at this time to show superiority of one catheter over another.

Catheters, Indwelling↗
PubMed2004

Novel regulation of mitotic exit by the Cdc42 effectors Gic1 and Gic2.

The guanine nucleotide exchange factor Cdc24, the GTPase Cdc42, and the Cdc42 effectors Cla4 and Ste20, two p21-activated kinases, form a signal transduction cascade that promotes mitotic exit in yeast. We performed a genetic screen to identify components of this pathway. Two related bud cortex-associated Cdc42 effectors, Gic1 and Gic2, were obtained as factors that promoted mitotic exit independently of Ste20. The mitotic exit function of Gic1 was dependent on its activation by Cdc42 and on the release of Gic1 from the bud cortex. Gic proteins became essential for mitotic exit when activation of the mitotic exit network through Cdc5 polo kinase and the bud cortex protein Lte1 was impaired. The mitotic exit defect of cdc5-10 Deltalte1 Deltagic1 Deltagic2 cells was rescued by inactivation of the inhibiting Bfa1-Bub2 GTPase-activating protein. Moreover, Gic1 bound directly to Bub2 and prevented binding of the GTPase Tem1 to Bub2. We propose that in anaphase the Cdc42-regulated Gic proteins trigger mitotic exit by interfering with Bfa1-Bub2 GTPase-activating protein function.

Adaptor Proteins, Signal Transducing↗
PubMed2001

Microbiology and risk factors for catheter exit-site and -hub colonization in neonatal intensive care unit patients.

OBJECTIVE: To identify risk factors and describe the microbiology of catheter exit-site and hub colonization in neonates. DESIGN: During a period of 2 years, we prospectively investigated 14 risk factors for catheter exit-site and hub colonization in 862 central venous catheters in a cohort of 441 neonates. Cultures of the catheter exit-site and hub were obtained using semiquantitative techniques at time of catheter removal. SETTING: A neonatal intensive care unit at a university hospital. RESULTS: Catheter exit-site colonization was found in 7.2% and hub colonization in 5.3%. Coagulase-negative staphylococci were predominant at both sites. Pathogenic flora were found more frequently at the catheter hub (36% vs 14%; P<.05). Through logistic regression, factors associated with exit-site colonization were identified as umbilical insertion (odds ratio [OR], 8.1; 95% confidence interval [CI95], 2.35-27.6; P<.001), subclavian insertion (OR, 54.6; CI95, 12.2-244, P<.001), and colonization of the catheter hub (OR, 8.9; CI, 3.5-22.8; P<.001). Catheter-hub colonization was associated with total parenteral nutrition ([TPN] OR for each day of TPN, 1.056; CI95, 1.029-1.083; P<.001) and catheter exit-site colonization (OR, 6.11; CI95, 2.603-14.34; P<.001). No association was found between colonization at these sites and duration of catheterization and venue of insertion, physician's experience, postnatal age and patient's weight, ventilation, steroids or antibiotics, and catheter repositioning. CONCLUSION: These data support that colonization of the catheter exit-site is associated with the site of insertion and colonization of the catheter hub with the use of TPN. There is a very strong association between colonization at both catheter sites.

Analysis of Variance↗
PubMed2004

The differential roles of budding yeast Tem1p, Cdc15p, and Bub2p protein dynamics in mitotic exit.

In the budding yeast Saccharomyces cerevisiae the mitotic spindle must be positioned along the mother-bud axis to activate the mitotic exit network (MEN) in anaphase. To examine MEN proteins during mitotic exit, we imaged the MEN activators Tem1p and Cdc15p and the MEN regulator Bub2p in vivo. Quantitative live cell fluorescence microscopy demonstrated the spindle pole body that segregated into the daughter cell (dSPB) signaled mitotic exit upon penetration into the bud. Activation of mitotic exit was associated with an increased abundance of Tem1p-GFP and the localization of Cdc15p-GFP on the dSPB. In contrast, Bub2p-GFP fluorescence intensity decreased in mid-to-late anaphase on the dSPB. Therefore, MEN protein localization fluctuates to switch from Bub2p inhibition of mitotic exit to Cdc15p activation of mitotic exit. The mechanism that elevates Tem1p-GFP abundance in anaphase is specific to dSPB penetration into the bud and Dhc1p and Lte1p promote Tem1p-GFP localization. Finally, fluorescence recovery after photobleaching (FRAP) measurements revealed Tem1p-GFP is dynamic at the dSPB in late anaphase. These data suggest spindle pole penetration into the bud activates mitotic exit, resulting in Tem1p and Cdc15p persistence at the dSPB to initiate the MEN signal cascade.

Anaphase↗