Continued development of the Nimbus/University of Pittsburgh (UOP) axial flow left ventricular assist system

Nimbus and the University of Pittsburgh (UOP) have continued the development of a totally implanted axial flow blood pump under the National Institutes of Health (NIH) Innovative Ventricular Assist System (IVAS) program. This 62 cc device has an overall length of 84 mm and an outer diameter of 34.5 mm. The inner diameter of the blood pump is 12 mm. It is being designed to be a totally implanted permanent device. A key achievement during the past year was the completion of the Model 2 pump design. Ten of these pumps have been fabricated and are being used to conduct in vitro and in vivo experiments to evaluate the performance of different materials and hydraulic components. Efforts for optimizing the closed loop speed control have continued using mathematical modeling, computer simulations, and in vitro and in vivo testing. New hydraulic blade designs have been tested using computational fluid dynamics (CFD) and flow visualization. A second generation motor was designed with improved efficiency. To support the new motor, a new motor controller fabricated as a surface mount PC board has been completed. The program is now operating under a formal QA system.     

Magnetic resonance imaging scanning in the diagnosis of zone II flexor tendon rupture

This study was undertaken to determine the usefulness of magnetic resonance imaging (MRI) in the diagnosis of flexor tendon rupture in patients who had prior surgery. Magnetic resonance imaging scans were performed on 11 digits (16 tendons) with the clinical diagnosis of flexor tendon rupture. Clinical suspicion correlated with MRI and surgical findings. Clinical examination yielded a 60% accuracy in diagnosis. MRI differentiated rupture from adhesions with a 100% accuracy rate. The MRI scan is a valuable tool in diagnosing tendon ruptures and may help reduce the incidence of unnecessary tendon explorations.     

International surveillance of bloodstream infections due to Candida species: frequency of occurrence and antifungal susceptibilities of isolates collected in 1997 in the United States, Canada, and South America for the SENTRY Program. The SENTRY Participant Group

An international program of surveillance of bloodstream infections (BSIs) in the United States, Canada, and South America between January and December 1997 detected 306 episodes of candidemia in 34 medical centers (22 in the United States, 6 in Canada, and 6 in South America). Eighty percent of the BSIs were nosocomial and 50% occurred in patients hospitalized in an intensive care unit. Overall, 53.3% of the BSIs were due to Candida albicans, 15.7% were due to C. parapsilosis, 15.0% were due to C. glabrata, 7.8% were due to C. tropicalis, 2.0% were due to C. krusei, 0.7% were due to C. guilliermondii, and 5.8% were due to Candida spp. However, the distribution of species varied markedly by country. In the United States, 43.8% of BSIs were due to non-C. albicans species. C. glabrata was the most common non-C. albicans species in the United States. The proportion of non-C. albicans BSIs was slightly higher in Canada (47.5%), where C. parapsilosis, not C. glabrata, was the most common non-C. albicans species. C. albicans accounted for 40.5% of all BSIs in South America, followed by C. parapsilosis (38.1%) and C. tropicalis (11.9%). Only one BSI due to C. glabrata was observed in South American hospitals. Among the different species of Candida, resistance to fluconazole (MIC, > or = 64 microg/ml) and itraconazole (MIC, > or = 1.0 microg/ml) was observed with C. glabrata and C. krusei and was observed more rarely among other species. Isolates of C. albicans, C. parapsilosis, C. tropicalis, and C. guilliermondii were all highly susceptible to both fluconazole (99.4 to 100% susceptibility) and itraconazole (95.8 to 100% susceptibility). In contrast, 8.7% of C. glabrata isolates (MIC at which 90% of isolates are inhibited [MIC90], 32 microg/ml) and 100% of C. krusei isolates were resistant to fluconazole, and 36.9% of C. glabrata isolates (MIC90, 2.0 microg/ml) and 66.6% of C. krusei isolates were resistant to itraconazole. Within each species there were no geographic differences in susceptibility to fluconazole or itraconazole.     

Experimental pyeloureterectomy and calyceal neck transection with autotransplantation and bladder advancement

OBJECTIVE: To determine whether Dexon mesh, closely applied to the kidney, provides purchase for sutures to permit bladder/parenchymal apposition on autotransplantation and that, if this line of apposition were some distance from but surrounding renal papillae, urothelium would proliferate to cover exposed parenchyma to form a widely patent lumen; this should facilitate removal of the whole of an upper tract collecting system, retaining renal parenchyma alone. MATERIALS AND METHODS: To test this possibility and explore the practicability of the concept, nine dogs underwent bilateral nephrectomy followed by unilateral autotransplantation: the other kidney was discarded. Because the canine renal pelvis is intrarenal, the ureter was stretched maximally before passing fine scissors into the renal hilum to transect the collecting system as close to the kidney as possible in six of the nine dogs. In the remaining three dogs, partial nephrectomy was performed with division of the calyceal necks under vision. Thinned bladder wall was sutured to Dexon mesh some distance from the collecting tubules; omentum was applied to the suture line. RESULTS: Three dogs were killed prematurely at < 2 weeks because of perioperative complications. Four were killed at 2, 4, 5 and 8 weeks and two at 12 months. Dexon mesh proved to be an effective anchoring fabric, providing close apposition of bladder wall and parenchyma. There was no adhesion of the kidney to peritoneal contents. Urothelial proliferation to cover exposed parenchyma occurred early and by 12 months, a thin stroma was interposed between parenchyma and epithelium. The kidney was preserved in all but one removed electively, this dog having both cystitis and pyelonephritis at 12 months. CONCLUSIONS: This study showed that autotransplantation of a kidney after removal of its collecting system and advancement of thinned bladder wall to renal parenchyma is practicable, with regenerated urothelium bridging the deficiency by covering exposed parenchyma, to create a widely patent lumen.     

Sequential transfer of free flap to two defects

This case report describes the use of a single lateral arm flap sequentially transferred to two defects in a bilateral hand injury. We believe this is a novel approach in reconstructing defects in bilateral hands when a staged reconstruction is planned.     

Chemotherapy in advanced ovarian cancer: four systematic meta-analyses of individual patient data from 37 randomized trials. Advanced Ovarian Cancer Trialists' Group

The purpose of this systematic study was to provide an up to date and reliable quantitative summary of the relative benefits of various types of chemotherapy (non-platinum vs platinum, single-agent vs combination and carboplatin vs cisplatin) in the treatment of advanced ovarian cancer. Also, to investigate whether well-defined patient subgroups benefit more or less from cisplatin- or carboplatin-based therapy. Meta-analyses were based on updated individual patient data from all available randomized controlled trials (published and unpublished), including 37 trials, 5667 patients and 4664 deaths. The results suggest that platinum-based chemotherapy is better than non-platinum therapy, show a trend in favour of platinum combinations over single-agent platinum, and suggest that cisplatin and carboplatin are equally effective. There is no good evidence that cisplatin is more or less effective than carboplatin in any particular subgroup of patients.     

The maximum watts factor as a measure of detrusor contractility independent of outlet resistance

The maximum watts factor (WFmax) is often used to characterize detrusor contractility. It was recently shown that the WFmax may increase in some patients with chronic outlet obstruction. It is, however, unclear whether this increase reflects a dependence of the WFmax on the degree of outlet obstruction or whether it represents a true increase in detrusor contractility secondary to chronic outlet obstruction. Therefore, this study was performed to investigate this issue using a canine model of acute outlet obstruction. Urodynamic studies were performed on adult canines with surgically exposed lower urinary tracts. Pressure transducers were used to measure the intravesical and the distal urethral pressures, whereas an ultrasonic flow meter was used to obtain a simultaneous measure of the urinary flow rate. Detrusor contractions were induced by electrically stimulating the pelvic nerves bilaterally. Varying degrees of outlet obstruction were created using an inflatable sphincter cuff secured around the bladder outlet. The WFmax, the detrusor pressure at voiding terminus (Pdet.clos), and the passive urethral resistance (R) were computed from measured pressure-flow rate data at each degree of outlet obstruction. The WFmax was not significantly correlated to either the sphincter cuff volume (r = 0.025, p = 0.871), the Pdet.clos (r = 0.286, p = 0.073) or the R (r = 0.110, p = 0.509). The WFmax was not significantly different among mild, moderate, and severe degrees of outlet obstruction (p = 0.176). Our results suggest that the WFmax is independent of the degree of acute outlet obstruction (defined in terms of the sphincter cuff volume, Pdet.clos and R). This validates the current practice of using the WFmax to evaluate detrusor function in patients with voiding dysfunction regardless of outlet resistance. Further, since the WFmax is independent of outlet obstruction acutely, it is reasonable that it would also be independent of outlet obstruction under chronic conditions. Our results, therefore, also imply that the increase in the WFmax with chronic outlet obstruction may represent a true increase in detrusor contractility and not a WFmax dependence on outlet resistance.     

Inhibitory effect of anaphylactic reaction of Sosiho-Tang

The Ilizarov method has broad applications for the generation of bone and soft tissue via an external fixator composed of small pins, tensional wires, rings, hinges and distractors. The success of the technique depends on adherence to Ilizarov's principles of tension-stress phenomenon: preservation of the tissues' blood supply, frequent distraction in small increments, and full function of the extremity.     

Local recurrence of breast cancer after cytological evaluation of lumpectomy margins

Successful breast conservation therapy with optimal cosmesis requires adequate tumor excision and negative tumor margins. Therefore, more sensitive techniques are being developed to identify lumpectomy margins intraoperatively with greater accuracy. Unidentified microscopic disease is seemingly responsible for a local recurrence rate of up to 25 per cent 3 to 5 years after lumpectomy and radiotherapy for breast cancer patients. As a result, Moffitt Cancer Center has routinely used an intraoperative touch preparation cytology (TPC) protocol to evaluate the entire resected surface of all lumpectomies. In addition, resection margins were also evaluated by gross examination and by standard histology. In rare instances frozen sections were used to evaluate tumor margins. In this study 701 consecutive lumpectomy specimens were evaluated by TPC during the period of 9 years with a mean follow-up of 3.5 years. Local cancer recurrence was 2.7 per cent (mean recurrence, 2.53 years), in women whose lumpectomy margins were evaluated by TPC. Of interest, a local recurrence rate of 14.6 per cent was observed in patients who had referral lumpectomies evaluated by conventional histopathology. This study suggests that accurate margin assessment with TPC plays an important role in the control of local recurrence after breast conservation therapy. Therefore, we conclude the routine use of intraoperative TPC provides rapid, reliable, topographically accurate identification of residual microscopic disease at lumpectomy margins.