Drought-induced changes in chlorophyll fluorescence in florists' cineraria and a xerophytic progenitor

Call number: LD2668 .T4 BIOL 1987 H46Master of ScienceBiolog

Functional interaction of chloroplast SRP/FtsY with the ALB3 translocase in thylakoids: substrate not required

Integration of thylakoid proteins by the chloroplast signal recognition particle (cpSRP) posttranslational transport pathway requires the cpSRP, an SRP receptor homologue (cpFtsY), and the membrane protein ALB3. Similarly, Escherichia coli uses an SRP and FtsY to cotranslationally target membrane proteins to the SecYEG translocase, which contains an ALB3 homologue, YidC. In neither system are the interactions between soluble and membrane components well understood. We show that complexes containing cpSRP, cpFtsY, and ALB3 can be precipitated using affinity tags on cpSRP or cpFtsY. Stabilization of this complex with GMP-PNP specifically blocks subsequent integration of substrate (light harvesting chl a/b-binding protein [LHCP]), indicating that the complex occupies functional ALB3 translocation sites. Surprisingly, neither substrate nor cpSRP43, a component of cpSRP, was necessary to form a complex with ALB3. Complexes also contained cpSecY, but its removal did not inhibit ALB3 function. Furthermore, antibody bound to ALB3 prevented ALB3 association with cpSRP and cpFtsY and inhibited LHCP integration suggesting that a complex containing cpSRP, cpFtsY, and ALB3 must form for proper LHCP integration

Predictors of Left Ventricular Remodeling after Aortic Valve Replacement in Pediatric Patients with Isolated Aortic Regurgitation

Objective. To identify the risk factors that could predict postoperative outcome after aortic valve replacement in pediatric patients with isolated aortic regurgitation ( AR ). Background. There is controversy regarding the appropriate timing of surgery in asymptomatic or minimally symptomatic patients with isolated AR . In the pediatric age group, there are limited studies in this regard and most of them are on combined aortic valve stenosis and regurgitation. Methods. All patients with biventricular physiology and morphologic left ventricle ( LV ) who underwent aortic valve surgery for AR from J anuary 1988 to J uly 2010 were included in the study. Demographic, clinical, and echocardiographic data were collected at presurgical visit, early postoperative, 1 year, and most recent follow‐up. Results. Among 53 patients (36 males), 18 had LV end‐diastolic diameter ( LVEDD ) z ‐score >4 standard deviation ( SD ) (group I ) and 35 had LVEDD 4 SD predicted persistent LV dilation (>2 SD ) at early post‐op ( P  4 SD ) are significant predictors of incomplete LV remodeling or persistent LV dysfunction.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/97538/1/chd703.pd

Prevalence and Risk Factors for Upper Airway Obstruction after Pediatric Cardiac Surgery

Objective To determine the prevalence of and risk factors for extrathoracic upper-airway obstruction after pediatric cardiac surgery. Study design A retrospective chart review was performed on 213 patients younger than 18 years of age who recovered from cardiac surgery in our multidisciplinary intensive care unit in 2012. Clinically significant upper-airway obstruction was defined as postextubation stridor with at least one of the following: receiving more than 2 corticosteroid doses, receiving helium-oxygen therapy, or reintubation. Multivariate logistic regression analysis was performed to determine independent risk factors for this complication. Results Thirty-five patients (16%) with extrathoracic upper-airway obstruction were identified. On bivariate analysis, patients with upper-airway obstruction had greater surgical complexity, greater vasoactive medication requirements, and longer postoperative durations of endotracheal intubation. They also were more difficult to calm while on mechanical ventilation, as indicated by greater infusion doses of narcotics and greater likelihood to receive dexmedetomidine or vecuronium. On multivariable analysis, adjunctive use of dexmedetomedine or vecuronium (OR 3.4, 95% CI 1.4-8) remained independently associated with upper-airway obstruction. Conclusion Extrathoracic upper-airway obstruction is relatively common after pediatric cardiac surgery, especially in children who are difficult to calm during endotracheal intubation. Postoperative upper-airway obstruction could be an important outcome measure in future studies of sedation practices in this patient population

Risk Factors for Extubation Failure following Neonatal Cardiac Surgery

Objective: Extubation failure after neonatal cardiac surgery has been associated with considerable postoperative morbidity, although data identifying risk factors for its occurrence are sparse. We aimed to determine risk factors for extubation failure in our neonatal cardiac surgical population. Design: Retrospective chart review. Setting: Urban tertiary care free-standing children’s hospital. Patients: Neonates (0–30 d) who underwent cardiac surgery at our institution between January 2009 and December 2012 was performed. Interventions: Extubation failure was defined as reintubation within 72 hours after extubation from mechanical ventilation. Multivariate logistic regression analysis was performed to determine independent risk factors for extubation failure. Measurements and Main Results: We included 120 neonates, of whom 21 (17.5%) experienced extubation failure. On univariate analysis, patients who failed extubation were more likely to have genetic abnormalities (24% vs 6%; p = 0.023), hypoplastic left heart (43% vs 17%; p = 0.009), delayed sternal closure (38% vs 12%; p = 0.004), postoperative infection prior to extubation (38% vs 11%; p = 0.002), and longer duration of mechanical ventilation (median, 142 vs 58 hr; p = 0.009]. On multivariate analysis, genetic abnormalities, hypoplastic left heart, and postoperative infection remained independently associated with extubation failure. Furthermore, patients with infection who failed extubation tended to receive fewer days of antibiotics prior to their first extubation attempt when compared with patients with infection who did not fail extubation (4.9 ± 2.6 vs 7.3 ± 3; p = 0.073). Conclusions: Neonates with underlying genetic abnormalities, hypoplastic left heart, or postoperative infection were at increased risk for extubation failure. A more conservative approach in these patients, including longer pre-extubation duration of antibiotic therapy for postoperative infections, may be warranted

Note and Comment

Internal Revenue Tax on State Dispensaries Upheld; What is the Practice of Medicine?; Appeals from Decrees for Costs; The Hearst Election Contest; The Lapse of a Legacy to a Deceased Child; Unsightly Advertisements and Billboard

Passive Peritoneal Drainage versus Pleural Drainage after Pediatric Cardiac Surgery

Background: We aimed to determine whether infants undergoing cardiac surgery would more efficiently attain negative fluid balance postoperatively with passive peritoneal drainage as compared to traditional pleural drainage. Methods: A prospective, randomized study including children undergoing repair of tetralogy of Fallot (TOF) or atrioventricular septal defect (AVSD) was completed between September 2011 and June 2013. Patients were randomized to intraoperative placement of peritoneal catheter or right pleural tube in addition to the requisite mediastinal tube. The primary outcome measure was fluid balance at 48 hours postoperatively. Variables were compared using t tests or Fisher exact tests as appropriate. Results: A total of 24 patients were enrolled (14 TOF and 10 AVSD), with 12 patients in each study group. Mean fluid balance at 48 hours was not significantly different between study groups, −41 ± 53 mL/kg in patients with periteonal drainage and −9 ± 40 mL/kg in patients with pleural drainage (P = .10). At 72 hours however, postoperative fluid balance was significantly more negative with peritoneal drainage, −52.4 ± 71.6 versus +2.0 ± 50.6 (P = .04). On subset analysis, fluid balance at 48 hours in patients with AVSD was more negative with peritoneal drainage as compared to pleural, −82 ± 51 versus −1 ± 38 mL/kg, respectively (P = .02). Fluid balance at 48 hours in patients with TOF was not significantly different between study groups. Conclusion: Passive peritoneal drainage may more effectively facilitate negative fluid balance when compared to pleural drainage after pediatric cardiac surgery, although this benefit is not likely universal but rather dependent on the patient’s underlying physiology

Report of the Advisory Committee in Seismology

The Advisory Committee in Seismology has pleasure in reporting the continued progress of its study of California earth movements during the year 1924-1925 without essential change of plan. A considerable amount of geologic work in the study of fault zones has been done during the year in the Mojave Desert and in Death Valley, the system of primary triangulation for the detection and measurement of horizontal displacements has progressed rapidly and effectively, and the development of suitable instruments for determining the two horizontal components of local earth movements has progressed to completion. Ground for a new laboratory has been purchased by the California Institute of Technology and the construction of the central station laboratory building upon it has been begun. The laboratory is expected to be occupied by Mr. H. O. Wood, Research Associate in Seismology, and his associates, about January 1, 1926. It is hoped that additional stations will also be occupied before the close of the present calendar year (1925), and that actual work in what has been happily termed the seismologic triangulation of California will be successfully inaugurated