HIV‐Positive‐to‐HIV‐Positive Liver Transplantation

Most countries exclude human immunodeficiency virus (HIV)‐positive patients from organ donation because of concerns regarding donor‐derived HIV transmission. The Swiss Federal Act on Transplantation has allowed organ transplantation between HIV‐positive donors and recipients since 2007. We report the successful liver transplantation from an HIV‐positive donor to an HIV‐positive recipient. Both donor and recipient had been treated for many years with antiretroviral therapy and harbored multidrug‐resistant viruses. Five months after transplantation, HIV viremia remains undetectable. This observation supports the inclusion of appropriate HIV‐positive donors for transplants specifically allocated to HIV‐positive recipients.     

Three‐decade‐delayed post‐traumatic small‐bowel stenosis

Injury to the small bowel is uncommon after trauma. There are rare reported cases of delayed post‐traumatic stenosis of the small bowel occurring weeks, months or even years later. In this study, we present a case of a delayed stenosis that caused a small‐bowel obstruction three decades after the trauma.     

Cartilage‐on‐cartilage versus metal‐on‐cartilage impact characteristics and responses

A common in vitro model for studying acute mechanical damage in cartilage is to impact an isolated osteochondral or cartilage specimen with a metallic impactor. The mechanics of a cartilage‐on‐cartilage (COC) impact, as encountered in vivo, are likely different than those of a metal‐on‐cartilage (MOC) impact. The hypothesis of this study was that impacted in vitro COC and MOC specimens would differ in their impact behavior, mechanical properties, chondrocyte viability, cell metabolism, and histologic structural damage. Osteochondral specimens were impacted with either an osteochondral plug or a metallic cylinder at the same delivered impact energy per unit area, and processed after 14 days in culture. The COC impacts resulted in about half of the impact maximum stress and a quarter of the impact maximum stress rate of change, as compared to the MOC impacts. The impacted COC specimens had smaller changes in mechanical properties, smaller decreases in chondrocyte viability, higher total proteoglycan content, and less histologic structural damage, as compared to the impacted MOC specimens. If MOC impact conditions are to be used for modeling of articular injuries and post‐traumatic osteoarthritis, the differences between COC and MOC impacts must be kept in mind. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 31: 887–893, 2013     

Organ‐preserving neodymium‐yttrium‐aluminium‐garnet laser therapy for penile carcinoma: a long‐term follow‐up

Study Type – Therapy (case series)
Level of Evidence 4

OBJECTIVE

To retrospectively analyse the long‐term follow‐up of 54 patients treated with organ‐preserving laser therapy for penile carcinoma, as such therapy provides excellent cosmetic and functional results, but recurrence rates are high, which might impair the oncological outcome and worsen tumour‐related survival.

PATIENTS AND METHODS

Between 1979 and 2008, 54 patients with penile carcinoma were treated with the neodymium‐doped yttrium‐aluminium‐garnet (Nd:YAG) laser at our institution; 11 were classified as having carcinoma in situ (Tis), 39 as T1 and four as T2.

RESULTS

There was local recurrence in 16 patients (42%); the mean (range) time to local recurrence was 53 (9–132) months. In half the patients the time to local recurrence was >53 months, with the latest recurrence at 132 months after initial therapy of primary tumour. There was no statistically significant difference in recurrence rates with Tis or invasive penile carcinoma. In lymph‐node‐negative patients at initial presentation, there were no newly developed positive lymph nodes during the follow‐up.

CONCLUSIONS

Organ‐preserving laser therapy showed a relatively high recurrence rate in patients with a long‐term follow up, but the oncological outcome and survival were not compromised by local recurrence. Therefore, laser therapy appears to be appropriate for treating premalignant lesions and early stages of penile carcinoma. Patients should be informed about the potential for late recurrence.     

Excellent Clinical Outcomes From a National Donation‐After‐Determination‐of‐Cardiac‐Death Lung Transplant Collaborative

Donation‐after‐Determination‐of‐Cardiac‐Death (DDCD) donor lungs can potentially increase the pool of lungs available for Lung Transplantation (LTx). This paper presents the 5‐year results for Maastricht category III DDCD LTx undertaken by the multicenter Australian National DDCD LTx Collaborative. The Collaborative was developed to facilitate interaction with the Australian Organ Donation Authority, standardization of definitions, guidelines, education and audit processes. Between 2006 and 2011 there were 174 actual DDCD category III donors (with an additional 37 potentially suitable donors who did not arrest in the mandated 90 min postwithdrawal window), of whom 71 donated lungs for 70 bilateral LTx and two single LTx. In 2010 this equated to an “extra” 28% of donors utilized for LTx. Withdrawal to pulmonary arterial flush was a mean of 35.2 ± 4.0 min (range 18–89). At 24 h, the incidence of grade 3 primary graft dysfunction was 8.5%[median PaO₂/FiO₂ ratio 315 (range 50–507)]. Overall the incidence of grade 3 chronic rejections was 5%. One‐ and 5‐year actuarial survival was 97% and 90%, versus 90% and 61%, respectively, for 503 contemporaneous brain‐dead donor lung transplants. Category III DDCD LTx therefore provides a significant, practical, additional quality source of transplantable lungs.     

An efficient intensity‐based ready‐to‐use X‐ray image stitcher

Background: The limited field of view of the X‐ray image intensifier makes it difficult to cover a large target area with a single X‐ray image. X‐ray image stitching techniques have been proposed to produce a panoramic X‐ray image. Methods: This paper presents an efficient intensity‐based X‐ray image stitcher, which does not rely on accurate C‐arm motion control or auxiliary devices and hence is ready to use in clinic. The stitcher consumes sequentially captured X‐ray images with overlap areas and automatically produces a panoramic image. The gradient information for optimization of image alignment is obtained using a back‐propagation scheme so that it is convenient to adopt various image warping models. Results: The proposed stitcher has the following advantages over existing methods: (1) no additional hardware modification or auxiliary markers are needed; (2) it is robust against feature‐based approaches; (3) arbitrary warping models and shapes of the region of interest are supported; (4) seamless stitching is achieved using multi‐band blending. Experiments have been performed to confirm the effectiveness of the proposed method. Conclusion: The proposed X‐ray image stitcher is efficient, accurate and ready to use in clinic.     

Investigation of High‐Speed Erythrocyte Flow and Erythrocyte‐Wall Impact in a Lab‐on‐a‐Chip

To better understand erythrocyte high‐speed motion, collision characteristics, and collision‐induced hemolysis probability in rotary blood pumps, a visual experimental investigation of high‐speed erythrocyte flow and erythrocyte‐wall collision in a lab‐on‐a‐chip was performed. The erythrocyte suspension was driven by a microsyringe pump connected to the microchip, and the erythrocyte flow and erythrocyte‐wall impact process were observed and imaged by an optical microscope and a high‐speed camera. Two types of microchips with different impact surfaces (flat and curved) were employed. The motion and deformation features before and after collision were studied in detail. The results show that erythrocytes not only move along the flow direction in the flow plane but also rotate and roll in three‐dimensional space. Erythrocytes keep discoid shape during the movement in the straight channel, but their deformations during collision are mainly classified into two types: erythrocyte structure is still stable and the erythrocyte performance can be ensured to a certain extent in the TypeA deformation, while the TypeB deformation makes the membrane more likely to fracture on the stretched side, increasing the probability of hemolysis. Furthermore, the movements and deformations of the erythrocytes after collision are analyzed and classified into two types: bouncing and slipping. Moreover, a simulation method for the flow in microchip was performed and validated through a comparison of the streamlines and experimental erythrocytes tracks, which can be further employed to predict the high‐speed blood flow, associated with collision process in mechanical blood pump.     

Sodium‐glucose co‐transporter type‐2 inhibitors: pharmacology and peri‐operative considerations

Sodium‐glucose co‐transporter 2 (SGLT2) inhibitors are an emerging class of oral hypoglycaemic agents with therapeutic benefits beyond better glycaemic control. A major concern of the sodium‐glucose co‐transporter 2 inhibitors is their propensity to cause euglycaemic ketoacidosis in the peri‐operative period and the potential for this critical diagnosis to be delayed or missed entirely. This review attempts to collate the case reports of sodium‐glucose co‐transporter 2 inhibitor ketoacidosis associated with surgery to highlight and put a perspective on this peri‐operative issue. Preventive strategies and the management of the ketoacidosis are discussed.     

Evaluation of Hyphecan (1‐4,2‐acetamide‐deoxy‐B‐D‐glucan polymer) on wound healing in a rodent model

Objective: To evaluate the effect of an artificial skin Hyphecan (1‐4,2‐acetamide‐deoxy‐B ‐D ‐glucan polymer) on wound healing in a rodent model. Materials and Method: The prospective study was conducted at a basic science laboratory at a tertiary teaching hospital. Two 4 cm × 4 cm full‐thickness wounds were created on the dorsal surface of 10 Spraque–Dawley rats and covered with Hyphecan and Kaltostat, respectively. Wounds were examined and measured on days 4, 10, 21 and 28, and would continue after day 28 until healed up completely. Punch biopsies (3 mm) were taken on days 4, 10 and 28 for histological examination of the response of healing and repair. Results: Despite the fact that the wound healing rate was similar for both groups on days 4, 10, 21 and 28, the average healing time for the Hyphecan group (29.1 ± 1.7 days) was significantly shorter statistically (P = 0.03) than the Kaltostat group (30.7 ± 2.8 days). Conversely, the marked healing response elicited by Hyphecan on day 4 persisted on days 10 and 28 in contrast to Kaltostat, which had only a mild degree of healing response on days 10 and 28. The study suggests that wounds treated by Hyphecan heal faster than Kaltostat. Conclusion: The findings provide basic scientific evidence supporting the clinical use of Hyphecan in different wounds and might also reduce the cost of wound management as Hyphecan is cheaper than Kaltostat and requires a shorter treatment time.      

Hamiltonian two‐degrees‐of‐freedom control of chemical reactors

A novel unified approach to two‐degrees‐of‐freedom control is devised and applied to a classical chemical reactor model. The scheme is constructed from the optimal control point of view and along the lines of the Hamiltonian formalism for nonlinear processes. The proposed scheme optimizes both the feedforward and the feedback components of the control variable with respect to the same cost objective. The original Hamiltonian function governs the feedforward dynamics, and its derivatives are part of the gain for the feedback component. The optimal state trajectory is generated online, and is tracked by a combination of deterministic and stochastic optimal tools. The relevant numerical data to manipulate all stages come from a unique off‐line calculation, which provides design information for a whole family of related control problems. This is possible because a new set of PDEs (the variational equations) allow to recover the initial value of the costate variable, and the Hamilton equations can then be solved as an initial‐value problem. Perturbations from the optimal trajectory are abated through an optimal state estimator and a deterministic regulator with a generalized Riccati gain. Both gains are updated online, starting with initial values extracted from the solution to the variational equations. The control strategy is particularly useful in driving nonlinear processes from an equilibrium point to an arbitrary target in a finite‐horizon optimization context. Copyright © 2010 John Wiley & Sons, Ltd.     

Manipulator‐driven selection of semi‐active MR‐visible markers

Background

A method for the identification of semi‐active fiducial magnetic resonance (MR) markers is presented based on selectively optically tuning and detuning them.

Methods

Four inductively coupled solenoid coils with photoresistors were connected to light sources. A microcontroller timed the optical tuning/detuning of coils and image collection. The markers were tested on an MR manipulator linking the microcontroller to the manipulator control to visibly select the marker subset according to the actuated joint.

Results

In closed‐loop control, the average and maximum were 0.76° ± 0.41° and 1.18° errors for a rotational joint, and 0.87 mm ± 0.26 mm and 1.13 mm for the prismatic joint.

Conclusions

This technique is suitable for MR‐compatible actuated devices that use semi‐active MR‐compatible markers.     

Dual‐energy X‐ray Absorptiometry in Canine Legg‐Calvé‐Perthes Disease

Radiographic examination and subsequent dual‐energy X‐ray absorptiometry scans of the hips were performed in seven dogs with monolateral Legg‐Perthes‐Calvé disease to quantify bone changes produced by osteonecrosis in the proximal femur on the affected and unaffected side. All dogs were found to be affected with grade 2 and 3 of the radiographic classification proposed by Ljunggren [Acta Orthop. Scand. (1967) vol. 95]. Bone mineral density (g/cm²) of the femoral neck and proximal femoral metaphysis were evaluated on the affected and unaffected side; we detected no differences in bone mineral density for both regions of interest within the population studied in relation to gender, body weight and side analysed nor between the affected and the unaffected limb. We therefore assume that radiographic areas of decreased density in the proximal femoral epiphysis during chronic stages of Legg‐Calvé‐Perthes disease do not alter the global mineral content of the scanned region.     

Low‐order multi‐rate linear time‐invariant decentralized trackers using the new observer‐based sub‐optimal method for unknown sampled‐data nonlinear time‐delay system with closed‐loop decoupling

This paper presents the low‐order multi‐rate linear time‐invariant decentralized trackers using the new observer‐based sub‐optimal method for a class of unknown sampled‐data nonlinear time‐delay system with closed‐loop decoupling. For the unknown sampled‐data nonlinear time‐delay system, we assume that the inner time delay is clearly known. Under this prerequisite, the appropriate (low‐) order decentralized linear observer for the unknown sampled‐data nonlinear system is determined by the off‐line observer/Kalman filter identification (OKID) method with artificial delay input and actual delay output. Then, the above observer has been further improved based on the proposed new observer‐based sub‐optimal approach. Sequentially, the decentralized tracker with the high gain property is proposed, so that the closed‐loop system has the decoupling property. The proposed approach constructs complete mathematics method including the concept of optimal control theory and state‐matching digital redesign technique and is quite useful for the complicated interconnected large‐scale sampled‐data nonlinear time‐delay system with unknown system equation. Copyright © 2010 John Wiley & Sons, Ltd.