Laboratory-based X-ray phase-contrast imaging technique for material and medical science applications.

In-line X-ray phase-contrast imaging technique is an emerging method for the study of materials such as carbon fibers, carbon composite materials, polymers, etc. Similarly this technique is also well suited for the imaging of soft materials such as tissues, distinguishing between tumor and normal tissue. These represent the class of materials for which X-ray attenuation cross-section is very small. Thus this method promises a far better contrast for low X-ray absorbing substances than the conventional radiography method. We have set up an experimental facility using a combination of X-ray CCD detector and a microfocus X-ray source. This facility is dedicated to micro-imaging experiments such as microtomography and high-resolution phase-contrast experiments. In this paper, the results of X-ray phase-contrast imaging experiments are described.     

Pediatric staghorn calculi: the role of extracorporeal shock wave lithotripsy monotherapy with special reference to ureteral stenting

PURPOSE: Treatment for staghorn calculi in children represents a unique challenge. We assessed the efficacy of extracorporeal shock wave lithotripsy (ESWL) (Dornier Medical Systems, Inc., Marietta, Georgia) monotherapy for the management of staghorn calculi in children with special reference to ureteral stenting. MATERIALS AND METHODS: From June 1992 to January 2001 we treated 42 children 9 months to 12 years old with staghorn stones using the Piezolith 2501 (Richard Wolf GmBH, Knittlingen, Germany) lithotriptor. The initial group of 19 patients underwent ESWL without prophylactic ureteral stenting, while in the latter group of 23 a Double-J (Medical Engineering Corp., New York, New York) ureteral stent was inserted immediately before the first ESWL session. Mean patient age, stone size, number of shock waves and ESWL sessions, hospital stay, stone-free rate and major complications were compared in the 2 groups. RESULTS: Overall 33 children (79%) were stone-free after 3 months. The 2 groups were comparable in regard to patient age, stone size, number of shock waves and ESWL sessions, and stone-free rates. Major complications developed in 21% of the unstented group, whereas none were observed in stented cases. This difference was statistically significant (p = 0.035). Seven post-ESWL auxiliary procedures were required in the unstented group to manage complications. Hospital stay was significantly longer in the unstented compared with the stented group (p = 0.022). At a followup of 9 to 102 months (mean 47) stones recurred in 2 children, who were treated with further ESWL. CONCLUSIONS: ESWL monotherapy was an efficient and safe modality for the treatment of staghorn calculi in children. Stented patients had fewer major complications and a shorter hospital stay. Prophylactic ureteral stenting is advisable before ESWL for staghorn calculi in children.     

Is primary endoscopic puncture of ureterocele a long-term effective procedure?

Background/Purpose: For more than a decade, endoscopic puncture of ureterocele has been recommended as an initial and, in the majority of the patients, as a definitive procedure. This study evaluates the long-term effectiveness of primary endoscopic puncture of ureterocele. Methods: Over the last 18 years (1984 through 2001), 52 patients (median age 3 months) underwent primary endoscopic puncture of ureterocele. The median follow-up was 9 years (6 months to 18 years). Antenatal ultrasound scan detected hydronephrosis and led to the postnatal diagnosis of ureterocele in 12 (23%) children, whereas in the remaining 40 (77%) children the diagnosis was made on investigation for urinary tract infection (UTI). The ureterocele presented as a part of renal duplication in 48 (92%) patients and a single system in 4 (8%). Forty-four (92%) of the patients with duplication presented with non- or poorly functioning upper poles. Vesicoureteric reflux (VUR) was seen in the lower moiety of the ipsilateral kidney in 31 and in 18 of the contralateral kidney comprising 49 renal refluxing units (RRU). Results: Complete decompression of the ureterocele was achieved in 48 (92%) patients after the first endoscopic puncture. Four (8%) patients required a second puncture of ureterocele. Nine (17%) of the 52 patients underwent nephrectomy for a nonfunctioning kidney. Ten (19%) patients required upper pole partial nephrectomy owing to nonfunctioning upper pole. Twenty-nine (59%) of the 49 RRU showed spontaneous resolution of VUR. Sixteen (33%) RRU underwent endoscopic correction of VUR. One required ureteric reimplantation. The remaining 4 (8%) are maintained on prophylactic antibiotics. Five (10%) patients had VUR in the upper pole moieties after ureterocele puncture. Conclusions: Our data suggest that primary endoscopic puncture of ureteroceles is a simple, long-term, effective, and safe procedure avoiding complete reconstruction in the majority of the patients. J Pediatr Surg 38:116-119.     

Aortic root surgery with circulatory arrest: Predictors of prolonged postoperative hospital stay

Objective

Little is known about the outcomes of aortic root operations that involve inducing hypothermic circulatory arrest for relatively extensive proximal aortic surgery. We attempted to identify predictors of postoperative hospital length of stay (LOS) and factors that affect postoperative recovery.

Laparoscopic partial nephrectomy: integration of an advanced laparoscopic technique

Background: Laparoscopic radical nephrectomy and open partial nephrectomy are now established methods of treatment for appropriate renal lesions suspicious for malignancy, Laparoscopic partial nephrectomy has undergone progressive evolution. The aim of this paper is to; (i) evaluate the current status of laparoscopic partial nephrectomy, and (ii) to place it in the Australian and New Zealand context by evaluating the necessary skill acquisition for advanced laparoscopic urology. Methods: The National Library of Medicine database (PubMed) was used to specifically search the available literature on laparoscopic partial nephrectomy, renal failure and nephrectomy, modular surgical training and laparoscopic training. Of the articles identified, selection was based on their contribution to the development of techniques, progressive clinical outcomes, as well as comparisons with current management. Results: The technique and outcomes of laparoscopic partial nephrectomy are now secure enough to treat anatomically complex tumours in laparoscopically experienced hands. For the appropriate patient with a small renal mass, the impact of radical nephrectomy and long‐term renal dysfunction needs to be considered, even in the presence of a normal contra‐lateral kidney. Robotic assisted laparoscopic surgery is expensive and may impair the acquisition of advanced iaparoscopic skills. Conclusion: Over the past 5 years, laparoscopic partial nephrectomy has developed to the stage where, with the necessary laparoscopic skill, it is now a standard of care at tertiary referral institutions. Widespread dissemination of advanced laparoscopic skills remains the next challenge.     

Dose-response effect of elevated plasma free fatty acid on insulin signaling

The dose-response relationship between elevated plasma free fatty acid (FFA) levels and impaired insulin-mediated glucose disposal and insulin signaling was examined in 21 lean, healthy, normal glucose-tolerant subjects. Following a 4-h saline or Liposyn infusion at 30 (n = 9), 60 (n = 6), and 90 (n = 6) ml/h, subjects received a 2-h euglycemic insulin (40 mU . m(-2) . min(-1)) clamp. Basal plasma FFA concentration ( approximately 440 micromol/l) was increased to 695, 1,251, and 1,688 micromol/l after 4 h of Liposyn infusion and resulted in a dose-dependent reduction in insulin-stimulated glucose disposal (R(d)) by 22, 30, and 34%, respectively (all P < 0.05 vs. saline control). At the lowest lipid infusion rate (30 ml/h), insulin receptor and insulin receptor substrate (IRS)-1 tyrosine phosphorylation, phosphatidylinositol (PI) 3-kinase activity associated with IRS-1, and Akt serine phosphorylation were all significantly impaired (P < 0.05-0.01). The highest lipid infusion rate (90 ml/h) caused a further significant reduction in all insulin signaling events compared with the low-dose lipid infusion (P < 0.05-0.01) whereas the 60-ml/h lipid infusion caused an intermediate reduction in insulin signaling. However, about two-thirds of the maximal inhibition of insulin-stimulated glucose disposal already occurred at the rather modest increase in plasma FFA induced by the low-dose (30-ml/h) lipid infusion. Insulin-stimulated glucose disposal was inversely correlated with both the plasma FFA concentration after 4 h of lipid infusion (r = -0.50, P = 0.001) and the plasma FFA level during the last 30 min of the insulin clamp (r = -0.54, P < 0.001). PI 3-kinase activity associated with IRS-1 correlated with insulin-stimulated glucose disposal (r = 0.45, P < 0.01) and inversely with both the plasma FFA concentration after 4 h of lipid infusion (r = -0.39, P = 0.01) and during the last 30 min of the insulin clamp (r = -0.43, P < 0.01). In summary, in skeletal muscle of lean, healthy subjects, a progressive increase in plasma FFA causes a dose-dependent inhibition of insulin-stimulated glucose disposal and insulin signaling. The inhibitory effect of plasma FFA was already significant following a rather modest increase in plasma FFA and develops at concentrations that are well within the physiological range (i.e., at plasma FFA levels observed in obesity and type 2 diabetes).     

Striatal dopamine and working memory

Recent studies have emphasized the importance of dopamine projections to the prefrontal cortex (PFC) for working memory (WM) function, although this system has rarely been studied in humans in vivo. However, dopamine and PFC activity can be directly measured with positron emission tomography (PET) and functional magnetic resonance imaging (fMRI), respectively. In this study, we examined WM capacity, dopamine, and PFC function in healthy older participants in order to test the hypothesis that there is a relationship between these 3 factors. We used the PET tracer 6-[18F]fluoro-L-m-tyrosine to measure dopamine synthesis capacity in the striatum (caudate, putamen), and event-related fMRI to measure brain activation during different epochs (cue, delay, probe) of a WM task. Caudate (but not putamen) dopamine correlated positively with WM capacity, whereas putamen (but not caudate) dopamine correlated positively with motor speed. In addition, delay-related fMRI activation in a left inferior prefrontal region was related to both caudate dopamine and task accuracy, suggesting that this may be a critical site for the integration of WM maintenance processes. These results provide new evidence that striatal dopaminergic function is related to PFC-dependent functions, particularly brain activation and behavioral performance during WM tasks.     

Comparative Analysis of Outcomes in Living and Deceased Donor Liver Transplants for Primary Sclerosing Cholangitis

Introduction  Primary sclerosing cholangitits (PSC) is a progressive fibrosing cholangiopathy eventually leading to end-stage liver disease (ESLD). While literature for deceased donor liver transplantation (DDLT) for PSC abounds, only a few reports describe live donor liver transplant (LDLT) in the setting of PSC. We present a single-center experience on survival outcomes and disease recurrence for LDLT and DDLT for ESLD secondary to PSC. Aim  The aim of this study was to analyze survival outcomes and disease recurrence for LDLT and DDLT for ESLD secondary to PSC. Patients and Methods  A retrospective review of 58 primary liver transplants for PSC-associated ESLD, performed between May 1995 and January 2007, was done. Patients were divided into two groups based on donor status. Group 1 (n = 14) patients received grafts from living donors, while group 2 (n = 44) patients received grafts from deceased donors. An analysis of survival outcomes and disease recurrence was performed. Recurrence was confirmed based on radiological and histological criteria. Results  Recurrence of PSC was observed in four patients in LDLT group and seven in DDLT group. Retransplantation was required in one patient in LDLT group and nine patients in DDLT group. One patient (7%) among LDLT and six patients (14%) among DDLT died. The difference in patient and graft survival was not statistically significant between the two groups (patient survival, p = 0.60; graft survival, p = 0.24). Conclusion  This study demonstrates equivalent survival outcomes between LDLT and DDLT for PSC; however, the rate of recurrence may be higher in patients undergoing LDLT.     

The ‘French Fry’ VAC technique: hybridisation of traditional open wound NPWT with closed incision NPWT

Surgical site occurrences (SSO), specifically surgical site infections represent a significant burden in the US health care system. It has been hypothesised that postoperative dressing can help drive down SSO. We describe the successful use of a novel technique combining both closed incision and open negative pressure wound therapy in the management of a high‐risk wound associated with lymphoedema of obesity.