Comparison of aortic root replacement in patients with Marfan syndrome

Objectives: Although the aortic-valve-sparing (AVS) reimplantation technique according to David has shown favorable durability results in mid-term and long-term studies, composite valve grafting (CVG) according to Bentall is still considered the standard procedure. Methods: Retrospectively, we evaluated the results of aortic root replacement of patients with Marfan syndrome (MFS) who underwent surgery between January 1995 and January 2010. MFS was diagnosed using the Ghent criteria. AVS was used in 58 patients and CVG in 30 patients with MFS. AVS was done for aortic-root aneurysm (n = 48) or aortic dissection type A (n = 10). CVG was used for aortic-root aneurysm in 14 patients or aortic dissection type A in 16 patients. The mean follow-up was 3.2 (95% CI: 2.4–4.2) years. Results: In both groups, 30-day mortality was 0%. Three patients (10.0%) in the CVG group required resternotomy for postoperative bleeding versus two patients (3.4%) in the AVS group (p = 0.3). At follow-up, mortality was 10% in the CVG group versus 3.4% in the AVS group (p = 0.3). Re-operation was required in two patients (3.4%) after AVS and in three patients after CVG (10%) (p = 0.3). Three patients (10.0%) who underwent CVG had endocarditis and two patients (6.7%) had a stroke during follow-up, whereas no endocarditis and stroke occurred after AVS. After 14 years, stratified event-free survival was better in the AVS group (event-free survival was 82.3% vs 58.6%, log-rank test p = 0.086), especially after aneurysm (p = 0.057). After 10 years, freedom from aortic regurgitation ≥II° in the AVS group was 80% for aneurysm and 50% after dissection (p = 0.524). Conclusion: The reimplantation technique according to David was associated with excellent survival, good valve function and a low rate of re-operation, endocarditis, and stroke. There was a trend to better event-free survival for AVS patients making it the procedure of choice in MFS patients.     

Endothelin activation and postoperative renal failure after human liver transplantation.

Renal failure is an established risk factor for impaired patient outcome after orthotopic liver transplantation (OLT). As the endothelin pathway is known to be involved in the development of acute renal failure (ARF), we designed a study to clarify its role in ARF following OLT. Twenty consecutive patients with intact kidney function scheduled for their first OLT were prospectively studied. Plasma big endothelin-1 (ET-1) levels were measured before surgery, after graft reperfusion, and on the first and second postoperative day. According to postoperative glomerular filtration rate (GFR), patients were assigned to the acute renal dysfunction group (ARDF) and the non-ARDF group. Each patient's GFR was estimated according to the 4-variable formula used in the modification of diet in renal disease before surgery, daily within the first postoperative week, and at 1, 3, 12, and 24 months after surgery. Postoperative mean big ET-1 levels correlated significantly with the maximum percent decrease of GFR within 3 days after OLT (P < 0.01). The proportion of patients who developed ARDF was significantly correlated to mean postoperative big ET-1 quartiles (P < 0.01). In the ARDF group, the percent decrease of GFR within 24 months was significantly higher (P < 0.05) as compared to the non-ARDF group. In conclusion, patients who develop ARDF immediately after OLT do not fully recover to baseline regarding long-term kidney function. Short-term GFR was significantly correlated with postoperative big ET-1 plasma levels, suggesting renal dysfunction is mediated by the activated endothelin system.     

Gadoxetic acid enhanced MRI for differentiation of FNH and HCA: a single centre experience

Objectives

Evaluation of enhancement characteristics of histopathologically confirmed focal nodular hyperplasias (FNHs) and hepatocellular adenomas (HCAs) with gadoxetic acid-enhanced MRI.

Methods

Sixty-eight patients with 115 histopathologically proven lesions (FNHs, n?=?44; HCAs, n?=?71) examined with gadoxetic acid-enhanced MRI were retrospectively enrolled (standard of reference: surgical resection, n?=?53 patients (lesions: FNHs, n?=?37; HCAs, n?=?53); biopsy, n?=?15 (lesions: FNHs, n?=?7; HCAs, n?=?18)). Two radiologists evaluated all MR images regarding morphological features as well as the vascular and hepatocyte-specific enhancement in consensus.

Results

For the hepatobiliary phase, relative enhancement of the lesions and lesion to liver enhancement were significantly lower for HCAs (mean, 48.7 (±48.4) % and 49.4 (±33.9) %) compared to FNHs (159.3 (±92.5) %; and 151.7 (±79) %; accuracy of 89 % and 90 %, respectively; P?<?0.001). Visual strong uptake of FNHs vs. hypointensity of HCAs in the hepatobiliary phase resulted in an accuracy of 92 %. This parameter was superior to all other morphological and dynamic vascular criteria alone and in combination (accuracy, 54–85 %).

Conclusions

For differentiation of FNHs and HCAs by means of MRI, gadoxetic acid uptake in the hepatobiliary phase was found to be superior to all other criteria alone and in combination.

Key Points

? EOB-MRI is well suited to differentiate FNHs and hepatocellular adenomas. ? For this purpose hepatobiliary phase is superior to unenhanced and dynamic imaging. ? Hepatobiliary phase (peripheral) hyper- or isointensity is typical for FNH. ? Hepatobiliary phase hypointensity is typical for hepatocellular adenomas. ? EOB-MRI helps to avoid misinterpretations of benign hepatocellular lesions.     

Alcohol acutely down-regulates urea synthesis in normal men

BACKGROUND: Human nitrogen balance studies suggest that alcohol up-regulates urea synthesis and promotes nitrogen catabolism, whereas animal studies conversely indicate that alcohol down-regulates urea synthesis, possibly via a redox effect. This study aimed to investigate the acute effects of alcohol exposure at a plasma concentration of about 10 mmol/liter on urea synthesis in healthy volunteers and to investigate whether methylene blue alleviates the effect of alcohol. METHODS: Eleven males were studied three times in a randomized sequence crossover design. They received either alanine infusion to control the rate of urea synthesis (control), alanine + alcohol, or alanine + alcohol + methylene blue. The substrate independent regulation of urea synthesis was studied by means of the functional hepatic nitrogen clearance, that is, the slope of the linear relation between blood amino nitrogen concentrations and rates of urea synthesis. RESULTS: Alcohol reduced functional hepatic nitrogen clearance to 37% and 51% during alcohol and alcohol + methylene blue infusion, respectively (p = 0.007). Accordingly, whole body nitrogen retention was higher during alcohol infusion. Glucagon, which up-regulates urea synthesis, increased during alcohol infusion. There was no change in insulin. Blood glucose was slightly lower at the end of the experiment when alcohol was infused. CONCLUSION: Low-dose infusion of alcohol acutely down-regulated urea synthesis in healthy volunteers, transiently favoring nitrogen preservation. The effect seemed not to depend on hormonal changes. It remains to be explored how the present results can be reconciled with the reported nitrogen wasting of chronic alcoholics.     

Temperature-induced changes in structural and physicochemical properties of vernix caseosa

The skin of the third trimester fetus and early newborn exhibits a complex, multifunctional, highly hydrated but viscous skin-surface biofilm called vernix caseosa (VC). During birth, VC undergoes a substantial change from an aqueous and warm surrounding into a gaseous and colder environment postnatally. The aim of this study was to investigate the structural and physicochemical changes in VC, which accompany physiologically relevant variations in environment parameters, such as temperature and humidity. A remarkable difference was observed in water release and uptake properties: dehydration and rehydration processes take place two to four times faster at 37 degrees C than at room temperature (RT). The dehydration was irreversible; rehydration was only possible to a final weight of 55% (37 degrees C) and 46% (RT) of the pre-desiccation weight. Differential scanning calorimetry showed two different overlapping phase transitions within physiological temperature range. Investigation of the lipid organization by Fourier transform infrared spectroscopy and small-angle X-ray diffraction revealed a more disordered state of lipids at 37 degrees C than at RT, which might explain the faster dehydration and rehydration process at 37 degrees C as well as the changes in thermotropic rheological behavior. In conclusion, we demonstrated that VC properties adjust to the fundamental change from the intrauterine to the post-natal environment.     

Noise-Optimized Virtual Monoenergetic Dual-Energy CT Improves Diagnostic Accuracy for the Detection of Active Arterial Bleeding of the Abdomen

Purpose

To evaluate diagnostic accuracy of a noise-optimized virtual monoenergetic imaging (VMI+) reconstruction technique for detection of active arterial abdominal bleeding on dual-energy (DE) CT angiography compared with standard image reconstruction.

Simultaneous assessment of cardiac perfusion and function using 5-dimensional imaging with Tc-99m teboroxime

BACKGROUND: Dynamic single photon emission computed tomography (SPECT) acquisition and reconstruction of early poststress technetium 99m teboroxime washout images has been shown to be useful in the detection of coronary disease. Assessment of poststress regional wall motion may offer additional use in assessing coronary disease. Our goal was to investigate the feasibility of simultaneously imaging myocardial ischemia and transient poststress akinesis using gated-dynamic SPECT. METHODS AND RESULTS: A gated-dynamic mathematical cardiac torso (MCAT) phantom was developed to model both teboroxime kinetics and cardiac regional wall motion. A lesion was simulated as having delayed poststress teboroxime washout together with a transient poststress wall motion abnormality. Gated projection data were created to represent a 3-headed SPECT system undergoing a total rotation of 480 degrees . The dynamic expectation-maximization reconstruction algorithm with postsmoothing across gating intervals by Wiener filtering, and the ordered-subset expectation maximization reconstruction algorithm with 3-point smoothing across gating intervals were compared. Compared with the ordered-subset expectation maximization with 3-point smoothing, the dynamic expectation-maximization algorithm with Wiener filtering was able to produce visually higher-quality images and more accurate left ventricular ejection fraction estimates. CONCLUSION: From simulations, we conclude that changing cardiac function and tracer localization possibly can be assessed by using a gated-dynamic acquisition protocol combined with a 5-dimensional reconstruction strategy.     

Autologous human keratinocytes cultured on membranes composed of benzyl ester of hyaluronic acid for grafting in nonhealing diabetic foot lesions: a pilot study

Diabetic foot complications are the most common cause of nontraumatic lower extremity amputations in the industrialised world. Unsatisfactory healing requires advanced therapeutic strategies, such as the use of skin grafts, which may represent a helpful option for wound coverage. Alternatively, a method using autologous keratinocytes grown to thin sheet grafts is available. The purpose of this pilot study was to investigate the application of autologous human keratinocytes cultured on membranes composed of benzyl ester of hyaluronic acid (Laserskin autograft) to diabetic foot ulcers. We studied 14 patients with type 2 diabetes mellitus and a nonhealing diabetic foot lesion, defined as existing longer than 6 months or with no wound healing apparent for 12 weeks. Between 7 and 64 days after the transplantation (depending on the size of the ulceration), 11/14 of the lesions were completely healed. The transplantation of autologous keratinocytes may allow faster closure of diabetic foot lesions and subsequently reduce length of hospitalization. This method can easily be planned with regard to logistics and time, and furthermore, this therapy option can be carried out by the diabetologist.     

Clinical significance of focal echogenic liver lesions

During a 4-year period, 53 focal echogenic liver lesions were demonstrated by sonography in 41 patients, in whom there was no evidence of metastatic origin. Most of the lesions were hemangiomas.One of the purposes of this study was to determine the characteristic ultrasound features for liver hemangioma. Small (less than 2 cm), homogeneous, echogenic, well-circumscribed, subcapsular lesions almost prove their hemangiomatous nature. Lesions with a diameter of more than 2 cm are usually more lobulated and heterogeneous. They are located more centrally in the liver and nearly all show a close anatomical relation with 1 of the hepatic veins. Very large lesions (greater than 5 cm) with a heterogeneous and irregular aspect suggest focal nodular hyperplasia, which must be proven by a Tc-isotopic liver scan.