Anatomical correction of the exstrophy-epispadias complex: analysis of 34 patients

OBJECTIVE: To evaluate the surgical procedures required for anatomical reconstruction of the bladder and penis in the exstrophy-epispadias complex. PATIENTS AND METHODS: All primary exstrophy-epispadias repairs carried out by one surgeon between 1987 and 1997 were reviewed. Bladder closure consisted of full extraperitoneal mobilization, transpositional omphaloplasty, drainage with ureteric and urethral catheters and immobilization with a 'frog-leg' plaster-cast or 'mermaid' dressings. Osteotomies were always performed when bladder closure was attempted after 37 h of age. Before 1990 the osteotomies were posterior vertical iliac (one patient) and subsequently anterior oblique iliac (10 patients). Pre-peritoneal herniotomies, in the absence of a clinical hernia, were included in the primary procedure after 1992. A modified Cantwell technique was used for epispadias repair and this was undertaken at a median of 16 months after bladder closure (range 6-30). RESULTS: Thirty-four patients (27 male) were reviewed; one patient had a chromosomal abnormality, a deletion in the short arm of chromosome 4. The male infants required a median of four procedures (range 2-5) for bladder closure, epispadias reconstruction and herniotomies, while the females needed a median of two (range 2-5). Complete bladder dehiscence, requiring re-closure with osteotomies, occurred in three cases (9%, two male). There were no dehiscences in the primary osteotomy group. Fistulae after epispadias repair occurred in four patients (17%). The bladder capacity increased to > 60 mL in 10 of 15 males by 36 months after epispadias repair. Only two of seven female infants attained a capacity of > 60 mL. Of the 15 infants who did not undergo herniotomy at primary closure, 13 subsequently developed inguinal hernias (one uni- and 11 bilateral) with incarceration occurring in two. Twelve infants underwent herniotomy at primary closure and six developed subsequent hernias (two uni- and four bilateral; P = 0.05) with documented incarceration in two. CONCLUSIONS: Anatomical correction of the exstrophy-epispadias complex remains challenging, but can be achieved with complication rates of < 20% for each stage. Bladder volumes large enough to permit adequate bladder neck reconstruction can be anticipated after epispadias repair in a large proportion of male infants, but remains small in female infants with low outlet resistance. Inguinal herniotomy at the time of bladder closure significantly reduces the incidence of subsequent herniation, which nevertheless remains high.     

Effect of bile/pancreatic secretions on absorption of radioactive or stable zinc. In vivo and in vitro studies

Biliary/pancreatic (B/P) secretions are a major component of endogenous secretions, and endogenously secreted Zn is a primary means of Zn homeostasis. This study examined whether B/P fluid alters the absorption/reabsorption of Zn and, in doing so, whether this contributes to homeostatic control of Zn. Animal experiments utilized rats fed 10 or 300 micrograms Zn/kg diet. An open-ended gut perfusion study in which 65Zn-labeled B/P fluid or 67Zn-labeled and digested diet found significantly decreased Zn absorption from B/P fluid. Although Zn absorption from both sources was less in animals fed diets higher in Zn, there was no interaction of treatment and diet. Further studies utilizing cultured human colon carcinoma cells (CACO-2) as in vitro models of gut enterocytes found that the presence of B/P fluid significantly decreased Zn retention and/or transport and resulted in a redistribution of cellular Zn after 1200 min of incubation. These studies show that a substance in B/P fluid can decrease the absorption of Zn and also suggest that dietary Zn and Zn associated with B/P secretions are absorbed from distinct pools. However, the lack of an interactive effect with diet, and the amount of time required to see differences in CACO-2 cells, suggest that differences in absorption are not a major contributor to Zn homeostasis.     

Implications of variable fluid resistance caused by start-up flow in microfluidic networks

Electrical circuit analogies are often used to design microfluidic systems because they simplify device design, providing simple relationships between fluid flow rate, driving forces, and channel dimensions. However, such approximations often significantly overestimate flow rates in situations where start-up energy losses from establishing kinetic head are similar in magnitude to the energy required to overcome viscous shear stresses, as is often the case within complex microfluidic networks. These reduced flows can be more accurately predicted within an electrical analogy framework that accounts for the nonlinear flow resistance generated on the transient regime of start-up flow. In this work, standard flow resistance expressions are modified to account for such effects, and the onset of nonlinear resistance is predicted by a dimensionless parameter, $\xi = Re\frac{D}{L},$ which is dependent on the Reynolds number and the channel length. As a demonstration, variable fluid resistance is shown to dramatically affect the flow performance of common microfluidic units such as T-junctions and serpentine channels, and the change in performance is accurately predicted. Experimental and theoretical analysis of T-junctions further shows that variable flow resistance causes the ratio of flows through the junction to converge toward unity with respect to an increasing total flow rate. In addition, serpentine channels are shown to exaggerate these start-up effects, owing to compounded energetic demand associated with changing a flow’s direction. As a result, serpentine channels cause the ratio of flow rates exiting a T-junction to diverge from unity with respect to an increasing flow rate.     

Radiometric normalization and image mosaic generation of ASTER thermal infrared data: An application to extensive sand sheets and dune fields

Data from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) have a significant advantage over previous datasets because of the combination of high spatial resolution (15-90 m) and enhanced multispectral capabilities, particularly in the thermal infrared (TIR) atmospheric window (8-12 μm) of the Earth where common silicate minerals are more easily identified. However, the 60 km swath width of ASTER can limit the effectiveness of accurately tracing large-scale features, such as eolian sediment transport pathways, over long distances. The primary goal of this paper is to describe a method for generating a seamless and radiometrically accurate ASTER TIR mosaic of atmospherically corrected radiance and from that, extract surface emissivity for arid lands, specifically, sand seas. The Gran Desierto in northern Sonora, Mexico was used as a test location for the radiometric normalization technique because of past remote sensing studies of the region, its compositional diversity, and its size. A linear approach was taken to transform adjacent image swaths into a direct linear relationship between image acquisition dates. Pseudo-invariant features (PIFs) were selected using a threshold of correlation between radiance values, and change-pixels were excluded from the linear regression used to determine correction factors. The degree of spectral correlation between overlapping pixels is directly related to the amount of surface change over time; therefore, the gain and offsets between scenes were based only on regions of high spectral correlation. The result was a series of radiometrically normalized radiance-at-surface images that were combined with a minimum of image edge seams present. These edges were subsequently blended to create the final mosaic. The advantages of this approach for TIR radiance (as opposed to emissivity) data include the ability to: (1) analyze data acquired on different dates (with potentially very different surface temperatures) as one seamless compositional dataset; (2) perform decorrelation stretches (DCS) on the entire dataset in order to identify and discriminate compositional units; and (3) separate brightness temperature from surface emissivity for quantitative compositional analysis of the surface, reducing seam-line error in the emissivity mosaic. The approach presented here is valid for any ASTER-related study of large geographic regions where numerous images spanning different temporal and atmospheric conditions are encountered.     

Agonist action at D2(long) dopamine receptors: ligand binding and functional assays

Clinical pathways are being introduced by hospitals to reduce costs and control unnecessary variation in care. We studied 766 inpatients to measure the impact of a perioperative clinical pathway for patients undergoing knee replacement surgery on hospital costs. One hundred twenty patients underwent knee replacement surgery before the development of a perioperative clinical pathway, and 63 patients underwent knee replacement surgery after pathway implementation. As control groups, we contemporaneously studied 332 patients undergoing radical prostatectomy (no clinical pathway in place for these patients) and 251 patients undergoing hip replacement surgery without a clinical pathway (no clinical pathway and same surgeons as patients having knee replacement surgery). Total hospitalization costs (not charges), excluding professional fees, were computed for all patients. Mean (+/-SD) hospital costs for knee replacement surgery decreased from $21,709 +/- $5985 to $17,618 +/- $3152 after implementation of the clinical pathway. The percent decrease in hospitalization costs was 1.56-fold greater (95% confidence interval 1.02-2.28) in the knee replacement patients than in the radical prostatectomy patients and 2.02-fold greater (95% confidence interval 1.13-5.22) than in the hip replacement patients. If patient outcomes (e.g., patient satisfaction) remain constant with clinical pathways, clinical pathways may be a useful tool for incremental improvements in the cost of perioperative care. Implications: Doctors and nurses can proactively organize and record the elements of hospital care results in a clinical pathway, also known as "care pathways" or "critical pathways." We found that implementing a clinical pathway for patients undergoing knee replacement surgery reduced the hospitalization costs of this surgery.     

Demonstration of the feasibility of emergency department immunization against influenza and pneumococcus

STUDY OBJECTIVE: To demonstrate the feasibility of systematic immunization against influenza and pneumococcus in a public emergency department. METHODS: This was a demonstration project conducted from October 21, 1996, through December 2, 1996, at Cook County Hospital, an inner-city hospital with a 1996 adult ED census of 120,449. Seventy-eight percent of patients are uninsured; 92% are people of color; 73% deny having a primary physician. Only 15% have emergency complaints. Nurses received standing orders that all nonemergency adult patients meeting Centers for Disease Control and Prevention criteria for high risk should be offered immunization against influenza and pneumococcus at triage. Cash prizes were offered to nurses appropriately immunizing the most patients. The date of immunization was entered into the computerized patient registration system, available to all providers within the county system. From November 4 through November 18, an extra nurse was assigned to triage to test for improvement in immunization rates. A time-motion study determined the time required per immunization on the basis of a convenience sample of 8 nurses drawn from all 3 shifts. RESULTS: Only 3% of identified high-risk patients reported previous pneumococcal immunization. Despite extreme variation in nurse performance, 2,631 patients (24% of patients triaged) were screened, and 716 high-risk patients were identified (27% of patients screened). A total of 1234 patients were immunized against influenza, and 241 patients were appropriately immunized against pneumococcus. Sixty-one percent of high-risk patients with no contraindication to influenza immunization were immunized against influenza. Thirty-five percent of high-risk patients not previously immunized against pneumococcus were immunized against pneumococcus. Immunizations per shift per triage nurse varied from 0 to 24. Median time for all activities related to immunization was 4 minutes (range, 2 to 10 minutes). There was no increase in immunization rates with the addition of an extra nurse at triage (95% confidence interval for odds ratio, .929 to 1.153). CONCLUSION: Systematic immunization against influenza and pneumococcus is both needed and feasible in a public ED. "Buy-in" by nurses is variable. Increased staffing alone does not improve immunization rates.     

Resting respiratory tract dendritic cells preferentially stimulate T helper cell type 2 (Th2) responses and require obligatory cytokine signals for induction of Th1 immunity

Consistent with their role in host defense, mature dendritic cells (DCs) from central lymphoid organs preferentially prime for T helper cell type 1 (Th1)-polarized immunity. However, the "default" T helper response at mucosal surfaces demonstrates Th2 polarity, which is reflected in the cytokine profiles of activated T cells from mucosal lymph nodes. This study on rat respiratory tract DCs (RTDCs) provides an explanation for this paradox. We demonstrate that freshly isolated RTDCs are functionally immature as defined in vitro, being surface major histocompatibility complex (MHC) II lo, endocytosishi, and mixed lymphocyte reactionlo, and these cells produce mRNA encoding interleukin (IL)-10. After ovalbumin (OVA)-pulsing and adoptive transfer, freshly isolated RTDCs preferentially stimulated Th2-dependent OVA-specific immunoglobulin (Ig)G1 responses, and antigen-stimulated splenocytes from recipient animals produced IL-4 in vitro. However, preculture with granulocyte/macrophage colony stimulating factor increased their in vivo IgG priming capacity by 2-3 logs, inducing production of both Th1- and Th2-dependent IgG subclasses and high levels of IFN-gamma by antigen-stimulated splenocytes. Associated phenotypic changes included upregulation of surface MHC II and B7 expression and IL-12 p35 mRNA, and downregulation of endocytosis, MHC II processing- associated genes, and IL-10 mRNA expression. Full expression of IL-12 p40 required additional signals, such as tumor necrosis factor alpha or CD40 ligand. These results suggest that the observed Th2 polarity of the resting mucosal immune system may be an inherent property of the resident DC population, and furthermore that mobilization of Th1 immunity relies absolutely on the provision of appropriate microenvironmental costimuli.     

Assessment of the nutritional state of dialysis patients

Obstructive sleep apnea syndrome (OSAS) has been associated with a higher than normal cardiovascular morbidity and mortality. Some OSAS patients lack the sleep-related, nocturnal decrease, or "dip," in blood pressure which is seen in normal individuals. These subjects, called "non-dippers," may be at greater risk for cardiovascular problems. We studied 40 OSAS patients (including 3 women) and 6 control subjects, all identified by polysomnography, for nocturnal blood pressure "dipping." We performed a second nocturnal polysomnogram to determine their apnea and hypopnea indices, (A + H)I, and oxygen saturation levels at the beginning of the study and then initiated 48 hours of ambulatory blood pressure monitoring, with data points collected every 30 minutes. Controls, which included one hypertensive subject, were all dippers. Nineteen OSAS subjects (48% of OSAS individuals) were systolic non-dippers and only 9 of them (22.5%) were diastolic non-dippers. We considered the following clinical variables as potential predictors of non-dipping: age, body mass index, respiratory disturbance index, years of reported loud snoring by bed partners, lowest oxygen saturation during nocturnal sleep, and percentage of sleep time spent with oxygen saturation below 90%. Multiple regression analyses indicated respiratory disturbance index as the only significant variable for systolic (p = 0.04) and diastolic (p = 0.03) blood pressure non-dipping. When we forced the following two nonsignificant variables into the model, they showed a very meager impact: number of years with reported loud snoring (p = 0.4 and p = 0.5, respectively for systolic and diastolic blood pressure non-dipping) and age (p = 0.5 and p = 0.6). The calculated model explained only a low percentage of the variance with an r2 of 0.25 and 0.26 for systolic and diastolic blood pressure non-dipping, respectively. Analysis of hypertension/normotension and dipping/non-dipping failed to show a significant relationship in the studied population. Fifty percent of the normotensive OSAS subjects were non-dippers and 43% of the hypertensive OSAS subjects were also non-dippers. We found a relationship between increasing respiratory disturbance index and increasing average 24-hour systolic blood pressure only when OSAS subjects were non-dippers and hypertensive.     

A study of the impact of the willingness-to-learn of CAD novice users on their competence development

The notion that ‘attitude drives behavior’ manifests itself in a variety of ways in educational and occupational settings. As applied to CAD competence development, industrial training of novice CAD users on their way to becoming competent CAD users consume a lot of corporate resources. This paper is the third paper in the line of research that attempts to answer the question having to do with what it takes to make a competent CAD user. Specifically, we examine the CAD-specific factors revolving around the trainees’ willingness-to-learn CAD.These factors are analyzed in two stages. At the start of the training, trainees’ initial attitude towards CAD is established by means of a short questionnaire. Afterwards, throughout the training, trainees’ behavior (online and offline practice) is gauged and, in turn, a relation is established to illustrate how this practice leads to the development of CAD-specific skills. For this purpose, another short questionnaire was utilized. Strong correlations were established relating the trainees’ CAD-specific behavior with the CAD-specific outcomes of learning CAD syntax.Furthermore, and in order to assess the quality of the trainees’ learning of CAD, overall competence was monitored throughout the study via performance measures that describe the time it took the trainees to build test models (speed), which reflects upon the ability to learn the syntax of the CAD tool (declarative knowledge). The sophistication of the models is also used as another measure. Correlating the trainees’ character attributes with these assessed measures, it was found that the stronger is the trainees’ will to learn CAD, the stronger is the likelihood to learn faster. Perhaps more importantly, trainees with initial favorable attitude toward CAD were shown to develop increasingly positive behavior that manifested through additional practice and other forms of visible effort.     

Analyzing CAD competence with univariate and multivariate learning curve models

Understanding how learning occurs, and what improves or impedes the learning process is of importance to academicians and practitioners; however, empirical research on validating learning curves is sparse. This paper contributes to this line of research by collecting and analyzing CAD (computer-aided design) procedural and cognitive performance data for novice trainees during 16-weeks of training. The declarative performance is measured by time, and the procedural performance by the number of features used to construct a design part. These data were analyzed using declarative or procedural performance separately as predictors (univariate), or a combination of declarative or procedural predictors (multivariate). Furthermore, a method to separate the declarative and procedural components from learning curve data is suggested.