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Desflurane is not associated with faster operating room exit times in outpatients.

STUDY OBJECTIVE: To determine the influence of anesthetic technique and primary drug on operating room (OR) exit time (time between end of surgery until time patient exists the OR) after addition of desflurane to the hospital formulary. DESIGN: Prospective study. SETTING: Ambulatory surgery unit of a university hospital. PATIENTS: 1,568 outpatients requiring anesthesia. INTERVENTIONS: Addition of desflurane to the hospital formulary, and substitution of desflurane vaporizers for enflurane vaporizers in the ambulatory surgery unit. MEASUREMENTS AND MAIN RESULTS: The following information was recorded for all anesthetic encounters over a six-month time interval: demographics, duration of surgery, primary anesthetic technique, primary anesthetic drug, and exit times. General anesthesia was used in 907 patients [desflurane: 209 patients, isoflurane: 429 patients, halothane: 192 patients, propofol: 72 patients, other intravenous (i.v.): 5 patients], major conduction anesthesia (spinal and epidural) in 43 patients, peripheral nerve blocks in 90 patients, and i.v. sedation in 528 patients. The exit time was significantly greater ( < 0.05) in patients who received general anesthesia (mean +/- SEM 14 +/- 0.2 min) compared with spinal/epidural (8 +/- 0.7 min), nerve blocks (8 +/- 0.4 min) and i.v. sedation (7 +/- 0.2 min). Exit times were longer in older patients receiving general anesthesia (exit time = 12.3 + 0.04 x age, SE = 6.7 min, p < 0.0009), whereas exit times were shorter in older individuals receiving i.v. sedation (exit time = 8.97 - 0.038 x age, SE = 3.6 min, p < 0.0001). For patients receiving i.v. sedation, exit times were shorter as duration of surgery increased (exit time = 7.86 - 0.015 x duration of surgery, SE = 3.6 min, p < 0.0002). Primary anesthetic drug did not affect exit times. CONCLUSION: Regional anesthesia and i.v. sedation were associated with faster OR exit times compared with general anesthesia. Despite desflurane's shorter elimination kinetics and recovery characteristics, use of this drug did not result in shorter exit times.

Adolescent↗

Central retinal vessel trunk exit and location of glaucomatous parapapillary atrophy in glaucoma.

OBJECTIVE: To evaluate whether the position of the central retinal vessel trunk exit on the lamina cribrosa spatially correlates with the location of parapapillary atrophy in glaucoma. DESIGN: Clinic-based, observational, cross-sectional study. PATIENTS: Color stereo optic disc photographs of 95 patients with primary or secondary open-angle glaucoma and 65 healthy persons were morphometrically evaluated. The intrapapillary and parapapillary region was divided into four quadrants. We determined the position of the central retinal vessel trunk exit on the lamina cribrosa surface and measured the area of parapapillary atrophy and neuroretinal rim in the four quadrants. MAIN OUTCOME MEASURES: The area of neuroretinal rim and parapapillary atrophy and the position of the central retinal vessel trunk exit. RESULTS: Comparing measurements between opposite disc quadrants showed that beta zone of parapapillary atrophy was significantly (P < 0.05) larger and that the neuroretinal rim was significantly smaller when beta zone and neuroretinal rim were measured in the disc quadrant most distant to the central retinal vessel trunk exit, than if the beta zone and neuroretinal rim were measured in the quadrant containing the vessel trunk exit. Comparing measurements in the disc quadrants between eyes with different positions of the central retinal vessel trunk exit revealed that, in the respective disc quadrant, the beta zone was significantly larger and the neuroretinal rim was smaller in eyes with the vessel trunk exiting in the opposite disc quadrant than in eyes with the vessel trunk exit located in the respective disc quadrant where the measurements were obtained. CONCLUSIONS: Position of the central retinal vessel trunk exit on the lamina cribrosa influences the location of parapapillary atrophy in glaucoma. The longer the distance to the central retinal vessel trunk exit, the more enlarged is parapapillary atrophy and the smaller is the neuroretinal rim. This relationship agrees with the spatial relationship between glaucomatous neuroretinal rim loss and enlarged parapapillary atrophy in glaucoma. Diagnostically, it may indicate that, in eyes with an abnormal configuration of parapapillary atrophy or with an abnormal position of the central retinal vessel trunk exit, early glaucomatous rim changes should be looked for in the disc sector that is most distant to the central retinal vessel trunk exit and where parapapillary atrophy may be relatively large.

Adult↗

Nursing interventions related to peritoneal catheter exit-site infections.

Nursing interventions related to peritoneal catheter exit-site infection include an emphasis on prevention and early diagnosis as well as exit-site care. The key elements to prevention of exit-site infections are avoiding trauma to the exit-site and tunnel, avoiding gross contamination of the exit-site, and cleaning a wet or dirty exit-site as soon as possible. Early diagnosis of exit-site infection is promoted by (1) teaching the patient or caregiver to assess the exit-site and tunnel routinely and to promptly recognize and report signs and symptoms of inflammation, and (2) routine exit-site evaluation by health care providers in the outpatient clinic. Care of the infected exit-site should focus on preventing cross contamination, keeping the exit-site dry, avoiding trauma and irritation, and in addition to routine care, may require removal of stubborn crusts and cauterization of proud flesh. Topical soaks and therapy have been recommended, but improvement of infected exit-sites has not been consistently documented.

Catheterization, Peripheral↗

Nursing practice related to peritoneal catheter exit site care and infections.

OBJECTIVE: The purpose of the study was to obtain information from nephrology nurses on existing policies and protocols related to peritoneal catheter exit site care and treatment of exit site infections. DESIGN: This was an explorative, descriptive study. SAMPLE/SETTING: Fifty-four nurses who attended the 1995 Consensus Conference on Peritoneal Dialysis at the 26th Annual American Nephrology Nurses' Association National Symposium completed a survey questionnaire on exit site care and management of exit site infections. METHODS: A survey was mailed to nephrology nurses preregistered to attend the 1995 ANNA Consensus Conference related to peritoneal dialysis at the 26th National Symposium. Surveys were also collected at the meeting. RESULTS: Hydrogen peroxide and povidone iodine are frequently used in the nursing care of both healing and chronic exit sites. Almost all of the dialysis units require patients to stabilize or secure the catheter. The majority of respondents had a standardized method of assessing exit sites. Risk factors for exit site infections are presented for both the immediate post-catheter insertion period and the well-healed exit site. There were many different combinations of cleansing agents used to treat inflamed and infected exit sites. CONCLUSIONS: Procedures for exit site care vary widely. Prospective, randomized studies of exit site care protocols and cleansing agents are necessary to determine the most effective procedures to promote healthy exit sites.

Catheters, Indwelling↗

The ex utero intrapartum treatment procedure: Looking back at the EXIT.

PURPOSE: The ex utero intrapartum treatment (EXIT) procedure was developed originally for management of airway obstruction after fetal surgery, and indications have continued to expand for a variety of fetal anomalies. The authors review their single-institution experience with EXIT. METHODS: Retrospective review of all patients who underwent an EXIT procedure from 1993 to 2003 (n = 52) was performed. Variables evaluated include indication for EXIT, gender, gestational age at EXIT, birth weight, maternal blood loss, operative complications, operative time, and survival rate. Technique, personnel, and anesthesic management were reviewed. RESULTS: Long-term follow-up was available for all patients. Fifty-one of 52 patients were born alive; currently, 27 of 52 patients (52%) are alive. All deaths have been in patients with congenital diaphragmatic hernia. Forty-five patients underwent EXIT for reversal of tracheal occlusion for congenital diaphragmatic hernia. Of these patients, 30 underwent tracheal clip removal. Two patients had repair of tracheal injury from clipping at EXIT. Fifteen patients underwent bronchoscopy and tracheal balloon removal. Five patients underwent EXIT procedure for neck masses. Tracheostomy was performed in 3 of these patients. One patient was intubated successfully, and 1 patient underwent resection of the neck mass while on placental support. Two patients underwent EXIT procedure and tracheostomy for congenital high-airway obstruction syndrome. Average gestational age at delivery was 31.95 +/- 2.55 weeks. Average birth weight was 1,895 +/- 653 g. Average maternal blood loss was 970 +/- 510 mL. Average operating time on placental support was 45 +/- 25 minutes with a maximum of 150 minutes. CONCLUSIONS: EXIT procedures can be performed with minimal maternal morbidity and with good outcomes. It is an excellent strategy for establishing an airway in a controlled manner, avoiding "crash" intubation or tracheostomy. Longer procedures on placental support allowing for definitive management of neck masses and airway obstruction have been realized. EXIT procedures have evolved from an adjunct to fetal surgery to a potentially life-saving procedure in fetuses with airway compromise at birth.

Airway Obstruction↗

Explaining discrepancies in reproductive health indicators from population-based surveys and exit surveys: a case from Rwanda.

OBJECTIVES: Reproductive health programmes often need exit surveys and population-based surveys for monitoring and evaluation. This study investigates why such studies produce discrepant estimates of condom use, sexual behaviour and condom brand knowledge, and discusses the implications for future use of exit surveys for programme monitoring. METHODS: Logistic regression is used to explain differences between a household survey of 1295 persons and an exit survey among a random sample of 2550 consumers at retail outlets in RWANDA: RESULTS: Discrepancies in ever use of condoms and risky sexual behaviours are due to differences in socioeconomic status of the two samples. After controls, exit surveys at most outlet types have the same results as the household survey. Only exit surveys at bars, nightclubs and hotels yield significantly different estimates. However, the above-average knowledge of Prudence Plus condoms in the exit interviews is not attributable to socioeconomic or demographic variables, most likely because respondents have seen the product at the outlets. CONCLUSIONS: Information about condom use and sexual behaviour obtained from exit surveys appears as accurate as that obtained through household surveys. Nevertheless, exit surveys must be used cautiously. Because exit surveys may include wealthier and better-educated respondents, they are not representative of the general population. The composition of exit survey samples should be validated through existing household surveys. Comparisons across survey types are generally unadvisable, unless they control for sample differences. When generalizing to the population at large is not needed (e.g. for studies aimed at identifying the characteristics and behaviour of users of particular products or services), exit surveys can provide an appropriate alternative to household surveys.

Adolescent↗

Frequent involvement of the internal cuff segment in CAPD peritonitis and exit-site infection - an ultrasound study.

BACKGROUND: The extent of involvement of the subcutaneous Tenckhoff catheter tract in CAPD peritonitis and catheter-related infections is of major therapeutic importance. By definition, both peritonitis and exit-site infections do not involve the catheter tract. However, diagnosis of these infections as well as the more sinister tunnel infection is based mainly on clinical signs. METHODS: We examined the usefulness of ultrasound examination (US) of the catheter tract in delineating catheter-related (exit-site and tunnel) infections, and their relationship to each other and to peritonitis. CAPD patients with no evidence of peritonitis or catheter-related infections for 6 months prior to examination served as controls. US were performed by one of two experienced radiologists using the Acuson 128XP/10 scanner with a 7-MHz linear transducer. A positive US was defined as an area of hypoechogenicity (indicative of fluid collection) >2 mm in width along any portion of the catheter tract. Findings were localized into segments(S) as follows: S1, limited to external cuff; S2, intercuff segment adjacent to the external cuff; S3, intercuff segment adjacent to the internal cuff; S4, limited to the internal cuff; and S5, involvement extending throughout the catheter tract. RESULTS: Between March 1993 and January 1995, 39 CAPD patients, all with a double-cuff straight Tenckhoff catheter with the exit site situated above the point of entry into the peritoneum were studied. A total of 56 US were performed divided among 26 episodes of peritonitis, four tunnel infections, 13 exit-site infections,and 13 controls. There were 30 positive US distributed among 16 peritonitis, four tunnel, eight exit site infections and two control patients. The two positive controls went on to develop peritonitis within 1 month of the US. The majority of the US findings (13/16 in episodes of peritonitis and 5/8 exit site infections were localized to segment 4, that is, to the internal cuff region. Apart from a significant increase in width in all infected segments versus a normal tunnel, no differences in size were seen between peritonitis, exit-site, or tunnel infections, nor were there any differences in size and localization in these infections when comparing the offending organism (Gram-positive, negative, or culture negative). CONCLUSIONS: We conclude that peritonitis and exit-site infections are frequently accompanied by involvement of the catheter tract. The localization of infection to the internal cuff region in cases of exit-site infection probably occurred as a result of downward migration along the catheter tract. This supports the notion that ideally the exit site should be pointing caudally or that the peritoneal catheter have a swan-neck configuration. With regard to peritonitis, infection within the peritoneal cavity appears to extend and involve the internal cuff region. Thus both the internal and external cuffs do not seem to pose an effective barrier against the spread of infection.. Based on our data, we recommend that US be performed as a routine investigation in all cases of exit-site infection and in cases of refractory or relapsing peritonitis.

Adult↗

Emperor penguins adjust swim speed according to the above-water height of ice holes through which they exit.

Emperor penguins leap from the water onto the sea ice. Their ability to reach above-water height depends critically on initial vertical speed of their leaping, assuming that the kinetic energy is converted to gravitational potential energy. We deliberately changed the above-water heights of ice hole exits, in order to examine whether penguins adjusted swim speed in accordance with the above-water height of the ice. Penguins were maintained in a corral on the fast ice in Antarctica, and voluntarily dived through two artificial ice holes. Data loggers were deployed on the penguins to monitor under water behavior. Nine instrumented penguins performed 386 leaps from the holes during experiments. The maximum swim speeds within 1 s before the exits through the holes correlated significantly with the above-water height of the holes. Penguins adopted higher speed to exit through the higher holes than through the lower holes. Speeds of some failed exits were lower than the theoretical minimum values to reach a given height. Penguins failed to exit onto the sea ice in a total of 37 of the trials. There was no preference to use lower holes after they failed to exit through the higher holes. Rather, swim speed was increased for subsequent attempts after failed leaps. These data demonstrated that penguins apparently recognized the above-water height of holes and adopted speeds greater than the minimal vertical speeds to reach the exit height. It is likely, especially in the case of higher holes (>40 cm), that they chose minimum speeds to exit through the holes to avoid excess energy for swimming before leaping. However, some exceptionally high speeds were recorded when they directly exited onto the ice from lower depths. In those cases, birds could increase swim speed without strokes for the final seconds before exit and they only increased the steepness of their body angles as they surfaced, which indicates that the speed required for leaps by emperor penguins were aided by buoyancy, and that penguins can sometimes exit through the ice holes without any stroking effort before leaping.

Animals↗

Adherence of Staphylococcus aureus isolated in peritoneal dialysis-related exit-site infections to HEp-2 cells and silicone peritoneal catheter materials.

BACKGROUND: Peritoneal catheter exit-site infections cause a relevant morbidity in peritoneal dialysis patients and are frequently caused by Staphylococcus aureus. We tested the hypothesis that adherence of exit-site-derived S. aureus to epithelial cells and peritoneal catheter silicone tubes discriminates virulent and less virulent strains. METHODS: The binding of isolated S. aureus to an epithelial cell line (HEp-2) and to silicone tubes was analyzed using light-microscopy or radioactive labeling of bacteria. RESULTS: Of 378 exit-site swabs, 99 (26%) were positive for microbial growth. S. aureus was cultured in 25 of 99 positive swabs; three of 13 swabs taken in exit-site infections grade 3 and 4 that had tested positive for S. aureus. Adherence of S. aureus from exit-site infections grade 2, 3 and 4 to Hep-2 cells did not differ from adherence of bacteria isolated from asymptomatic or moderately inflamed catheter exit sites (grade 0-2). However, binding of S. aureus to silicone tubes was enhanced in grade 0/1 compared with grade 2-4 exit-site isolates. CONCLUSIONS: Staphylococcus aureus is an important pathogen in CAPD-related exit-site infection being isolated in about 6.6% of all exit-site swabs (and in 25% of all positive swabs). Silicone-adhesive strains may be of more clinical significance in peritoneal dialysis patients since adhesion to silicone was increased in S. aureus strains isolated in more severe exit-site infections.

Bacterial Adhesion↗

Late emigrating neural crest cells migrate specifically to the exit points of cranial branchiomotor nerves.

Morphological segmentation of the avian hindbrain into rhombomeres is also reflected by the emergent organisation of branchiomotor nerves. In each case, the motor neurons of these nerves lie in two adjacent rhombomeres (e.g. of the Vth nerve in r2 and r3, VIIth in r4 and r5 etc.), and their outgrowing axons emerge into the periphery through defined exit points in rhombomeres r2, r4 and r6, respectively. Sensory axons of the cranial ganglia also enter the neuroepithelium at the same points. Motor axon outgrowth through experimentally rotated rhombomeres has suggested that a chemoattractive mechanism, involving the exit points, may form a component of their guidance. Yet so far, nothing is known about the establishment of the exit points or the identity of the cells that form them. In this study, we describe a group of late emigrating cranial neural crest cells which populate specifically the prospective exit points. Using chimaeras in which premigratory chick neural crest had been replaced orthotopically by quail cells, a population of neural crest was found to leave the cranial neural tube from about stage 10+ onwards and to migrate directly to the prospective exit points. These cells define the exit points by stage 12+, long before either motor or sensory axons have grown through them. The entire neural crest population of exit point cells expresses the recently described cell adhesion molecule c-cad7. Further, heterotopic grafting experiments show that midbrain and spinal cord crest, grafted at late stages in place of r4 crest, share the same migratory behaviour to the facial nerve exit points and express the same markers as cells contributed by the native r4 crest. It was not possible to generate new exit points in odd numbered rhombomeres simply by experimentally increasing their (normally insignificant) amount of crest production. Initiation of the exit point region probably lies, therefore, in the neuroepithelium.

Animals↗

Pseudomonas exit site infections in continuous ambulatory peritoneal dialysis patients.

The purpose of this study is to examine the natural history of Pseudomonas aeruginosa exit site infections in continuous ambulatory peritoneal dialysis (CAPD) patients treated with oral ciprofloxacin and local exit site care. A retrospective view was undertaken of 18 episodes of P. aeruginosa exit site infections developing in 17 patients maintained on CAPD during 1989 and 1990. Standardized therapy for the exit site infection consisted of oral ciprofloxacin (500 mg twice daily) and local exit site care with antiseptic agents. Fifteen (83%) of 18 of the pseudomonas exit site infections resolved with therapy. Three episodes (17%) required catheter removal to successfully eradicate the infection. Four of the 15 patients whose exit site infections resolved developed P. aeruginosa peritonitis 2 to 9 months after the clinical resolution of the exit site infection. The majority of pseudomonas exit site infections in CAPD patients can be successfully treated with oral ciprofloxacin and local care. Approximately 17% of the patients in this study required catheter removal to successfully eradicate the infection and an additional 22% of the patients developed pseudomonas peritonitis several months after the resolution of the exit site infection.

Administration, Oral↗

Prospective comparison of downward and lateral peritoneal dialysis catheter tunnel-tract and exit-site directions.

OBJECTIVE: Guidelines for optimal peritoneal dialysis access support both downward and lateral exit-site directions. Numerous clinical reports support the superiority of downward exit sites but none substantiate lateral configurations. METHODS: This prospective study compared infectious and mechanical complications between 85 catheters with a preformed arcuate bend to produce a downward exit site and 93 catheters with a straight intercuff segment configured to create a lateral exit site. RESULTS: Kaplan-Meier survivals were not different for time to first exit-site infection (p = 0.62), tunnel infection (p = 0.89), or peritonitis (p = 0.38) for downward and lateral exit-site directions. Poisson regression showed no differences in rates (episodes/patient-year) of exit-site infection (0.26 vs 0.27, p = 0.86), tunnel infection (0.02 vs 0.03, p = 0.79), peritonitis (0.42 vs 0.43, p = 0.87), or catheter loss (0.06 vs 0.09, p = 0.29) for downward and lateral exit sites. Kaplan-Meier analyses of antibiotic-free intervals for exit-site (p = 0.94) and peritonitis infections (p = 0.72) were not different for the two groups. There was one case of catheter tip displacement with flow dysfunction in each group. There were no pericatheter hernias or spontaneous cuff extrusions. Catheter survival between groups was not different (p = 0.20). CONCLUSIONS: Catheter types employing downward and lateral tunnel-tract and exit-site configurations produce equivalent outcomes for infectious and mechanical complications.

Catheter-Related Infections↗

Fire exit is a potential four transmembrane protein expressed in developing Drosophila glia.

Glia from many diverse organisms play a number of important roles during the development of the nervous system. Therefore, knowing the molecules that control glial cell function will further our understanding of the mechanisms that control nervous system development. We have isolated a novel gene in Drosophila melanogaster that is expressed in a subset of the peripheral glia. We call this gene "Fire exit" (Fie), as the glia that express this gene do so during a time when they mark the entry and exit point of axons at the CNS/PNS boundary. This subset of peripheral glia act as intermediate targets during pathfinding and migration of the sensory axons in particular. Fire exit has been cloned and found to encode a novel transmembrane protein. Fire exit belongs to a group of proteins identified in the Drosophila melanogaster and Anopheles gambiae databases which contain four predicted transmembrane domains and a shared intracellular motif. Mutations that remove the fire exit protein have no obvious disruption to glial function. On the other hand, glia expressing the Fire exit gene bridge the transition zone between CNS and PNS and play a role in sensory axon guidance. Therefore, it appears that, while the glia that express this protein mediate axon guidance, Fire exit itself plays a nonessential part in this function. A role for Fire exit in glial development may be suggested by its evolutionary relationship to a family of lysosome-associated proteins called LAPTMs and suggests that Fire exit may function in intracellular transport during glial development.

Amino Acid Sequence↗

Microtubule dependency of p34cdc2 inactivation and mitotic exit in mammalian cells.

The protein kinase inhibitor 2-aminopurine induces checkpoint override and mitotic exit in BHK cells which have been arrested in mitosis by inhibitors of microtubule function (Andreassen, P. R., and R. L. Margolis. 1991. J. Cell Sci. 100:299-310). Mitotic exit is monitored by loss of MPM-2 antigen, by the reformation of nuclei, and by the extinction of p34cdc2-dependent H1 kinase activity. 2-AP-induced inactivation of p34cdc2 and mitotic exit depend on the assembly state of microtubules. During mitotic arrest generated by the microtubule assembly inhibitor nocodazole, the rate of mitotic exit induced by 2-AP decreases proportionally with increasing nocodazole concentrations. At nocodazole concentrations of 0.12 microgram/ml or greater, 2-AP induces no apparent exit through 75 min of treatment. In contrast, 2-AP brings about a rapid exit (t1/2 = 20 min) from mitotic arrest by taxol, a drug which causes inappropriate overassembly of microtubules. In control mitotic cells, p34cdc2 localizes to kinetochores, centrosomes, and spindle microtubules. We find that efficient exit from mitosis occurs under conditions where p34cdc2 remains associated with centrosomal microtubules, suggesting it must be present on these microtubules in order to be inactivated. Mitotic slippage, the natural reentry of cells into G1 during prolonged mitotic block, is also microtubule dependent. At high nocodazole concentrations slippage is prevented and mitotic arrest approaches 100%. We conclude that essential components of the machinery for exit from mitosis are present on the mitotic spindle, and that normal mitotic exit thereby may be regulated by the microtubule assembly state.

2-Aminopurine↗

Prevalence and significance of exit block during arrhythmias arising in pulmonary veins.

INTRODUCTION: Recent studies described the occurrence of conduction block within pulmonary veins. The purpose of this study was to evaluate the prevalence of exit block during arrhythmias that arise in pulmonary veins. METHODS AND RESULTS: Twenty-five patients with atrial tachycardia/fibrillation underwent successful ablation of 28 arrhythmogenic foci within a pulmonary vein. The prevalence of exit block in the pulmonary veins was determined in 28 arrhythmogenic pulmonary veins and 40 nonarrhythmogenic pulmonary veins. During isolated premature depolarizations, exit block in a pulmonary vein was observed at 50% of arrhythmogenic pulmonary vein sites and was never observed within pulmonary veins that did not generate a tachycardia (P < 0.01). During tachycardia, exit block from a pulmonary vein was observed in 61% of the arrhythmogenic pulmonary veins. The mean cycle length of the pulmonary vein tachycardias associated with exit block was significantly shorter than the cycle length of tachycardias that were not associated with exit block (163 +/- 32 vs 251 +/- 45 msec, P < 0.001). Exit block in two pulmonary veins during the same episode of tachycardia was observed in 3 of the 28 arrhythmogenic pulmonary veins (11%) in three different patients. Simultaneous recordings in the two pulmonary veins demonstrated bursts of tachycardia in both veins that were not synchronized. Radiofrequency catheter ablation of the arrhythmogenic site in one of the pulmonary veins eliminated spontaneous recurrences of tachycardia from the other pulmonary vein. CONCLUSION: Exit block from pulmonary veins is a common observation during tachycardias generated within pulmonary veins and indicates that an arrhythmogenic pulmonary vein has been identified. The occurrence of exit block in more than one pulmonary vein most likely is attributable to simultaneous tachycardias, one or both of which may be tachycardia induced and perpetuated by the other.

Adult↗

Successful use of sodium hypochlorite pack plus systemic and local antibiotic therapy for the treatment of pseudomonas infection of peritoneal dialysis catheter exit-site.

Peritoneal catheter exit-site and tunnel infections remain critical problems in patients undergoing peritoneal dialysis. Catheter-related peritonitis occurs in about 20% of patients and exit-site infections are responsible for catheter removal in more than one-fifth of the cases. For the last 2 years in the Department of Nephrology, San Bortolo Hospital, Vicenza, Italy, we have been treating exit-site infections caused by Pseudomonas with sodium hypochlorite packs as well as systemic and local antibiotic therapy. Considering the encouraging results obtained on Pseudomonas infection, we decided to utilize the same schedule for the treatment of exit-site infections caused by other germs which are generally difficult to eradicate to prevent peritonitis and catheter removal. Between 2003 and 2004, 10 patients contracted infection of the exit-site. All patients underwent a swab test because of the reddening and the purulent secretion of the exit-site. The swab resulted positive for Pseudomonas in 7 patients, Corynebacterium sp. in 2 patients, and Candida albicans in 1 patient. All patients were treated with systemic antibiotic therapy or antifungal therapy, local sodium hypochlorite 50% packs. After 15 days all patients were submitted to a swab test of the exit site. In all patients, the swab test resulted negative after 15 days and 1 month, and they could continue peritoneal dialysis. This procedure avoided peritoneal catheter removal and temporary switch to hemodialysis in all patients with exit site infection. The mechanism of action is related to the wide antimicrobial spectrum and the rapid action of sodium hypochlorite possibly creating a protective barrier on the exit-site.

Anti-Bacterial Agents↗

E1A can provoke G1 exit that is refractory to p21 and independent of activating cdk2.

E1A can evoke G1 exit in cardiac myocytes and other cell types by displacing E2F transcription factors from tumor suppressor "pocket" proteins and by a less well-characterized p300-dependent pathway. Bypassing pocket proteins (through overexpression of E2F-1) reproduces the effect of inactivating pocket proteins (through E1A binding); however, pocket proteins associate with a number of molecular targets apart from E2F. Hence, pocket protein binding by E1A might engage mechanisms for cell cycle reentry beyond those induced by E2F-1. To test this hypothesis, we used adenoviral gene transfer to express various E2F-1 and E1A proteins in neonatal rat cardiac myocytes that are already refractory to mitogenic serum, in the absence or presence of several complementary cell cycle inhibitors-p16, p21, or dominant-negative cyclin-dependent kinase-2 (Cdk2). Rb binding by E2F-1 was neither necessary nor sufficient for G1 exit, whereas DNA binding was required; thus, exogenous E2F-1 did not merely function by competing for the Rb "pocket." E2F-1-induced G1 exit was blocked by the "universal" Cdk inhibitor p21 but not by p16, a specific inhibitor of Cdk4/6; p21 was permissive for E2F-1 induction of cyclins E and A, but prevented their stimulation of Cdk2 kinase activity. In addition, E2F-1-induced G1 exit was blocked by dominant-negative Cdk2. Forced expression of cyclin E induced endogenous Cdk2 activity but not G1 exit. Thus, E2F-1-induced Cdk2 function was necessary, although not sufficient, to trigger DNA synthesis in cardiac muscle cells. In contrast, pocket protein-binding forms of E1A induced G1 exit that was resistant to inhibition by p21, whereas G1 exit via the E1A p300 pathway was sensitive to inhibition by p21. Both E1A pathways-via pocket proteins and via p300-upregulated cyclins E and A and Cdk2 activity, consistent with a role for Cdk2 in G1 exit induced by E1A. However, p21 blocked Cdk2 kinase activity induced by both E1A pathways equally. Thus, E1A can cause G1 exit without an increase in Cdk2 activity, if the pocket protein-binding domain is intact. E1A also overrides p21 in U2OS cells, provided the pocket protein-binding domain is intact; thus, this novel function of E1A is not exclusive to cardiac muscle cells. In summary, E1A binding to pocket proteins has effects beyond those produced by E2F-1 alone and can drive S-phase entry that is resistant to p21 and independent of an increase in Cdk2 function. This suggests the potential involvement of other endogenous Rb-binding proteins or of alternative E1A targets.

Adenovirus E1A Proteins↗

[In vivo dosimetry. Assessment of exit dose correction factors].

INTRODUCTION: In vivo dosimetry allows to verify dose delivering accuracy in radiotherapy treatments. Exit dose measurements add more information about delivered dose than entrance dose evaluations. MATERIALS AND METHODS: Commercial semiconductor diodes are used for exit dose measurements. The diodes are calibrated by comparison with an ionization chamber at a reference condition. Diode reading was compared with the dose measured by the ionization chamber at the exit point. The exit point is defined as the point on the central axis of the beam, at a distance equal to the maximum dose from the exit surface of a homogeneous water-like phantom. As clinical irradiation conditions are always different from reference conditions, exit dose correction factors have been investigated as a function of phantom thickness, field size at the isocenter, source-surface distance, wedge and tray. Measurements have been performed by irradiating a set of p-type semiconductor detectors with 6 MV photon beam (four diodes--mod. EDP10--Scanditronix) and 18 MV photon beam (three diodes--mod. EDP20--Scanditronix) from a Clinac 1800 linear accelerator (Varian, Palo Alto, CA, USA). RESULTS: The most relevant exit dose correction factors are related to field size and phantom thickness for 6 MV photons. The variation of these factors as a function of field size may be greater than 1% with a standard deviation of the same order. On the contrary, the correction factors for field, thickness and tray photons are negligible for 18 MV. CONCLUSIONS: Applying exit dose correction factors may require a great effort, particularly when many silicon diodes must be used. The actual effectiveness of each calibration factor is evaluated through the statistical analysis of experimental data. In this way, the usefulness of correction factor calculation, as depending from both experimental conditions and diode responses, can be derived from its effects on the exit dose value.

Radiotherapy Dosage↗