The incidence, morbidity, and mortality of surgical procedures after orthotopic heart transplantation

OBJECTIVE: The authors present their experience with patients having undergone orthotopic heart transplantation (OHT) in whom surgical conditions subsequently developed that required operative intervention. The incidence, morbidity, and mortality of these procedures are reported. SUMMARY BACKGROUND DATA: Several studies have evaluated the management options of biliary tract disease after OHT. Multiple reports of patients having undergone OHT who subsequently underwent peripheral vascular reconstructions, plastic reconstructive, and thoracic procedures also have been published. METHODS: A chart review of 349 patients who underwent OHT between 1985 and 1996 was conducted to identify surgical procedures that were required in the post-transplant period. Their outcomes are reported. RESULTS: Of 349 patients who underwent OHT, conditions requiring 94 surgical procedures developed in 54 patients (15%). Biliary tract disease developed in 17 patients (5%) who required cholecystectomy, 2 of the 5 patients with acute cholecystitis died. Eight patients (2%) underwent orthopedic procedures with no operative mortality. Flap advancements for sternal wound infections were performed in five patients and four deaths occurred. Seventeen thoracic procedures were performed in 11 patients with an overall mortality of 45%. Twenty-one vascular procedures were performed on 17 patients with 1 delayed death due to a malignancy. Seven patients underwent procedures of the colon and rectum with no mortality. Seven patients underwent repair of inguinal or incisional hernias with no mortality. Various infections occurred with one resultant death after operative intervention. Six procedures were performed for diseases of the small intestine with no resultant mortalities. CONCLUSIONS: Patients having undergone OHT and chronic immunosuppression are at increased risk of having complications develop from infection. Acute cholecystitis and sternal wound infection caused an inordinate risk of complications and death. Malignancies developed in four patients who required surgical intervention. A heightened awareness of coexisting peripheral vascular disease in patients transplanted for ischemic cardiomyopathy should exist. Close screening before surgery and surveillance after surgery to identify risk factors for infection and vascular disease and to screen for malignancies are essential.     

Trapped thrombus in a patent foramen ovale

A survey of the orthopaedic casualties evacuated (casevacs) to the Royal Hospital Haslar between November 1995 and April 1996 was performed. A total of 464 service persons and civilians were casevaced. Orthopaedic cases amounted to 55% of all evacuations. Of these, 54% were British Army personnel. Conditions necessitating casevac were classified as either acute, (occurring during the deployment), or chronic (where the condition was present prior to deployment). Of the acute cases, there was an even mix between bony and soft tissue injuries (STIs). Sporting activities were the commonest cause of injury. The condition had been present prior to deployment in 16% of cases. Half of these were considered to have been unfit for deployment. Strategies for prevention of unnecessary casevacs are discussed.     

Low molecular weight Cooperia oncophora antigens. Potential to discriminate between susceptible and resistant calves after infection

The recognition of low molecular weight proteins by sera obtained during a single oral (primary) infection with 100,000 3rd-stage Cooperia oncophora larvae was studied in calves. Three groups of 6 or 7 calves were selected based on different egg excretion patterns. SDS-gel electrophoresis of adult Cooperia antigen under reducing conditions, followed by Western blotting, revealed that resistance of individual calves to C. oncophora might be related with antibody responses (42 days post infection) against at least 2 protein fragments (14-16 kDa and 27 kDa). The 14-16-kDa protein complex was bound, to some extent, by individual sera from all calves. The intensity of staining was negatively correlated with egg excretion on Day 42 p.i. Calves with high egg counts on Day 21 p.i. either did not or only weakly recognized the 27-kDa band. It has to be established whether the 14-16 kDa (or recombinant 14.2 kDa) provides a tool for immunodiagnostics and whether the 27-kDa fragment can help further unravel immune-mediated resistance to Cooperia.     

Dose escalation of cyclophosphamide in patients with breast cancer: consequences for pharmacokinetics and metabolism

PURPOSE: The alkylating anticancer agent cyclophosphamide (CP) is a prodrug that undergoes a complex metabolism in humans producing both active and inactive metabolites. In parallel, unchanged CP is excreted via the kidneys. The aim of this study was to investigate the influence of dose escalation on CP pharmacokinetics and relative contribution of activating and inactivating elimination pathways. PATIENTS AND METHODS: Pharmacokinetics of CP were assessed in 12 patients with high-risk primary breast cancer who received an adjuvant chemotherapy regimen that included four courses of conventional-dose CP (500 mg/m2 over 1 hour every 3 weeks) followed by one final course of high-dose CP (100 mg/kg over 1 hour). Plasma concentrations of CP were analyzed by high-performance liquid chromatography (HPLC), 24-hour urinary concentrations of CP, and its inactive metabolites (carboxyphosphamide, dechloroethylcyclophosphamide [dechlorethylCP], ketocyclophosphamide [ketoCP]) were determined by 31-phosphorus-nuclear magnetic resonance (31P-NMR)-spectroscopy. RESULTS: There was no difference in dose-corrected area under the concentration-time curve (AUC) (216 v 223 [mumol.h/[mL.g]), elimination half-life (4.8 v 4.8 hours), systemic clearance (79 v 77 mL/min) and volume of distribution (0.49 v 0.45 L/kg) of CP between conventional- and high-dose therapy, respectively. However, during high-dose chemotherapy, we observed a significant increase in the renal clearance of CP (15 v 23 mL/min; P < .01) and in the formation clearance of carboxyphosphamide (7 v 12 mL/min; P < .05) and dechloroethylCP (3.2 v 4.2 mL/min; P < .05), whereas metabolic clearance to ketoCP remained unchanged (1.3 v 1.2 mL/min). Consequently, metabolic clearance to the remaining (reactive) metabolites decreased from 52 to 38 mL/min (P < .001). The relative contribution of the different elimination pathways to overall clearance of CP demonstrated wide interindividual variability. CONCLUSION: Overall pharmacokinetics of CP are apparently not affected during eightfold dose escalation. However, there is a shift in the relative contribution of different clearances to systemic CP clearance in favor of inactivating elimination pathways, thereby indicating saturation of bioactivating enzymes during dose escalation. Besides individual enzyme capacity, hydration and concomitant medication with dexamethasone modulated CP disposition.     

The mechanisms of cracks formation of silver-based contact materials under arc and making pressure

The arc erosion experiments on five kinds of silver-based contact materials,AgZnO (10), AgSnO2 (8.5) In2O3 (4), AgCdO (12), AgNi(10), AgWC(12)C(3) were carried out according to different breaking times, breaking currents, and making pressures. Then based on the theoretical analysis and the photographs taken by scanning electronic microscope with EDAX analyzer, the crack morphology was studied scientifically. Three types of cracks, which are cavity cracks, grain boundaries (or phase boundaries) slipping cracks, and thermal stress cracks, were put forward under arc and making pressure through establishing their physical models and discussing their formation mechanisms.     

Replica time integrators

This paper is concerned with the classical problem of wave propagation in discrete models of nonuniform spatial resolution. We develop a new class of Replica Time Integrators (RTIs) that permit the two‐way transmission of thermal phonons across mesh interfaces. This two‐way transmissibility is accomplished by representing the state of the coarse regions by means of replica ensembles, consisting of collections of identical copies of the coarse regions. In dimension d, RTIs afford an O(n^d) speed‐up factor in sequential mode, and O(n^{d + 1}) in parallel, over regions that are coarsened n‐fold. In this work, we restrict ourselves to the solution of the 3d continuous wave equation, for both linear and non‐linear materials. By a combination of phase‐error analysis and numerical testing, we show that RTIs are convergent and result in exact two‐way transmissibility at the Courant–Friedrichs–Lewy limit for any angle of incidence. In this limit, RTIs allow step waves and high‐frequency harmonics to cross mesh interfaces in both directions without internal reflections or appreciable loss or addition of energy. The possible connections of RTIs with discrete‐to‐continuum approaches and, in particular, with the transition between molecular dynamics and continuum thermodynamics are also pointed to by way of future outlook. Copyright © 2011 John Wiley & Sons, Ltd.     

Tricubic interpolation in three dimensions

The purpose of this paper is to give a local tricubic interpolation scheme in three dimensions that is both C¹ and isotropic. The algorithm is based on a specific 64 × 64 matrix that gives the relationship between the derivatives at the corners of the elements and the coefficients of the tricubic interpolant for this element. In contrast with global interpolation where the interpolated function usually depends on the whole data set, our tricubic local interpolation only uses data in a neighbourhood of an element. We show that the resulting interpolated function and its three first derivatives are continuous if one uses cubic interpolants. The implementation of the interpolator can be downloaded as a static and dynamic library for most platforms. The major difference between this work and current local interpolation schemes is that we do not separate the problem into three one‐dimensional problems. This allows for a much easier and accurate computation of higher derivatives of the extrapolated field. Applications to the computation of Lagrangian coherent structures in ocean data are briefly discussed. Copyright © 2005 John Wiley & Sons, Ltd.     

Does palpability of primary cutaneous melanoma predict dermal invasion?

BACKGROUND: Relatively few studies have addressed the question of whether clinical estimation of melanoma thickness by palpation can accurately predict its histologic thickness. If palpability was a reliable predictor of dermal invasion, it could be used to define the surgical margin. OBJECTIVE: We sought to determine whether clinical elevation of melanoma could be used to predict the presence or absence and the degree of dermal invasion in patients with stage 1 cutaneous melanoma. METHODS: Melanomas in 165 patients were categorized by one observer as flat, just palpable, palpable, or nodular. This was compared with histologic measurements of tumor thickness. RESULTS: Overall there was significant correlation between the degree of palpability of melanoma and the presence or absence of dermal invasion (p<0.001), Breslow thickness (p<0.0001), and Clark level (p<0.001). However, the relation between palpability and Breslow thickness for invasive melanomas less than 1 mm thick was weaker (n=62, p=0.053), and the correlation between elevation and Clark level was not significant for invasive melanomas less than 4 mm thick (n=111, p>0.999). CONCLUSION: We conclude that palpability of melanoma is an inadequate guide to the presence or absence and degree of dermal invasion in melanomas less than 1 mm thick and cannot be used to determine the surgical margin.