Parametric imaging for characterizing focal liver lesions in contrast-enhanced ultrasound.

The differentiation between benign and malignant focal liver lesions plays an important role in diagnosis of liver disease and therapeutic planning of local or general disease. This differentiation, based on characterization, relies on the observation of the dynamic vascular patterns (DVP) of lesions with respect to adjacent parenchyma, and may be assessed during contrast-enhanced ultrasound imaging after a bolus injection. For instance, hemangiomas (i.e., benign lesions) exhibit hyper-enhanced signatures over time, whereas metastases (i.e., malignant lesions) frequently present hyperenhanced foci during the arterial phase and always become hypo-enhanced afterwards. The objective of this work was to develop a new parametric imaging technique, aimed at mapping the DVP signatures into a single image called a DVP parametric image, conceived as a diagnostic aid tool for characterizing lesion types. The methodology consisted in processing a time sequence of images (DICOM video data) using four consecutive steps: (1) pre-processing combining image motion correction and linearization to derive an echo-power signal, in each pixel, proportional to local contrast agent concentration over time; (2) signal modeling, by means of a curve-fitting optimization, to compute a difference signal in each pixel, as the subtraction of adjacent parenchyma kinetic from the echopower signal; (3) classification of difference signals; and (4) parametric image rendering to represent classified pixels as a support for diagnosis. DVP parametric imaging was the object of a clinical assessment on a total of 146 lesions, imaged using different medical ultrasound systems. The resulting sensitivity and specificity were 97% and 91%, respectively, which compare favorably with scores of 81 to 95% and 80 to 95% reported in medical literature for sensitivity and specificity, respectively.

Posterior auricular perichondrial cutaneous graft combined with cartilage strip in nostril reconstruction.

Objective: Reconstruction of alar structures of the nose remains difficult. The result has to be not only functional but also aesthetic. Different solutions to reconstruct alar defects are feasible. A good result that meets the specific demands on stability, aesthetics, and stable architecture without shrinkage of the area is not easily achieved. Method: A perichondrial cutaneous graft (PCCG), a graft consisting of a perichondral layer, fatty tissue, and skin that is harvested retroauriculary, is combined with an attached cartilage strip. Case Result: A 72-year-old patient suffering from basal cell carcinoma of the ala of the nose underwent the reconstructive procedure with a good result in 1 year in terms of stability, color match, and graft take. Conclusion: First, a strip of cartilage had been included in a PCCG where tumor resection required sacrifice of more than 50% of the alar rim. The case shows that one can consider a cartilage strip-enhanced PCCG graft to reconstruct alar defects.

Glucose transporters in the regulation of intestinal, renal, and liver glucose fluxes.

Five functional mammalian facilitated hexose carriers (GLUTs) have been characterized by molecular cloning. By functional expression in heterologous systems, their specificity and affinity for different hexoses have been defined. There are three high-affinity transporters (GLUT-1, GLUT-3 and GLUT-4) and one low-affinity transporter (GLUT-2), and GLUT-5 is primarily a fructose carrier. Because their Michaelis constants (Km) are below the normal blood glucose concentration, the high-affinity transporters function at rates close to maximal velocity. Thus their level of cell surface expression greatly influences the rate of glucose uptake into the cells. In contrast, the rate of glucose uptake by GLUT-2 (Km = 17 mM) increases in parallel with the rise in blood glucose over the physiological concentration range. High-affinity transporters are found in almost every tissue, but their expression is higher in cells with high glycolytic activity. Glut-2, however, is found in tissues carrying large glucose fluxes, such as intestine, kidney, and liver. As an adaptive response to variations in metabolic conditions, the expression of these transporters is regulated by glucose and different hormones. Thus, because of their specific characteristics and regulated expression, the facilitated glucose transporters control fundamental aspects of glucose homeostasis. I review data pertaining to the structure and regulated expression of the glucose carriers present in intestine, kidney, and liver and discuss their role in the control of glucose flux into or out of these different tissues.

Characterization of CD4+ CD25+ T cells in solid organ transplant recipients

Although important progresses have been achieved in the therapeutic management of transplant recipients, acute and chronic rejections remain the leading causes of premature graft loss after solid organ transplantation. This, together with the undesirable side effects of immunosuppressive drugs, has significant implications for the long-term outcome of transplant recipients. Thus, a better understanding of the immunological events occurring after transplantation is essential. The immune system plays an ambivalent role in the outcome of a graft. On one hand, some T lymphocytes with effector functions (called alloreactive) can mediate a cascade of events eventually resulting in the rejection, either acute or chronic, of the grafted organ ; on the other hand, a small subset of T lymphocytes, called regulatory T cells, has been shown to be implicated in the control of these harmful rejection responses, among other things. Thus, we focused our interest on the study of the balance between circulating effectors (alloreactive) and regulatory T lymphocytes, which seems to play an important role in the outcome of allografts, in the context of kidney transplantation. The results were correlated with various variables such as the clinical status of the patients, the immunosuppressive drugs used as induction or maintenance agents, and past or current episodes of rejection. We observed that the percentage of the alloreactive T lymphocyte population was correlated with the clinical status of the kidney transplant recipients. Indeed, the highest percentage was found in patients suffering from chronic humoral rejection, whilst patients on no or only minimal immunosuppressive treatment or on sirolimus-based immunosuppression displayed a percentage comparable to healthy non-transplanted individuals. During the first year after renal transplantation, the balance between effectors and regulatory T lymphocytes was tipped towards the detrimental effector immune response, with the two induction agents studied (thymoglobulin and basiliximab). Overall, these results indicate that monitoring these immunological parameters may be very useful for the clinical follow-up of transplant recipients ; these tests may contribute to identify patients who are more likely to develop rejection or, on the contrary, who tolerate well their graft, in order to adapt the immunosuppressive treatment on an individual basis.

A liver protein fraction regulating hormone-dependent in vitro transcription from the vitellogenin genes induces their expression in Xenopus oocytes.

Xenopus laevis oocytes were used to assay for trans-acting factors shown previously to be involved in the liver-specific regulation of the vitellogenin genes in vitro. To this end, crude liver nuclear extracts obtained from adult estrogen-induced Xenopus females were fractionated by heparin-Sepharose chromatography using successive elutions with 0.1, 0.35, 0.6, and 1.0 M KCl. When these four fractions were injected into oocytes, only the 0.6-M KCl protein fraction significantly stimulated mRNA synthesis from the endogenous B class vitellogenin genes. This same fraction induced estrogen-dependent in vitro transcription from the vitellogenin B1 promoter, suggesting that it contains at least a minimal set of basal transcription factors as well as two positive factors essential for vitellogenin in vitro transcription, i.e. the NF-I-like liver factor B and the estrogen receptor (ER). The presence of these two latter factors was determined by footprinting and gel retardation assays, respectively. In contrast, injection of an expression vector carrying the sequence encoding the ER was unable to activate transcription from the oocyte chromosomal vitellogenin genes. This suggests that the ER alone cannot overcome tissue-specific barriers and that one or several additional liver components participate in mediating tissue-specific expression of the vitellogenin genes. In this respect, we present evidence that the oocyte germinal vesicles contain an NF-I-like activity different from that found in hepatocytes of adult frogs. This observation might explain the lack of vitellogenin gene activation in oocytes injected with the ER cDNA only.

Transcript profiling suggests that differential metabolic adaptation of mice to a high fat diet is associated with changes in liver to muscle lipid fluxes.

Genetically homogenous C57Bl/6 mice display differential metabolic adaptation when fed a high fat diet for 9 months. Most become obese and diabetic, but a significant fraction remains lean and diabetic or lean and non-diabetic. Here, we performed microarray analysis of "metabolic" transcripts expressed in liver and hindlimb muscles to evaluate: (i) whether expressed transcript patterns could indicate changes in metabolic pathways associated with the different phenotypes, (ii) how these changes differed from the early metabolic adaptation to short term high fat feeding, and (iii) whether gene classifiers could be established that were characteristic of each metabolic phenotype. Our data indicate that obesity/diabetes was associated with preserved hepatic lipogenic gene expression and increased plasma levels of very low density lipoprotein and, in muscle, with an increase in lipoprotein lipase gene expression. This suggests increased muscle fatty acid uptake, which may favor insulin resistance. In contrast, the lean mice showed a strong reduction in the expression of hepatic lipogenic genes, in particular of Scd-1, a gene linked to sensitivity to diet-induced obesity; the lean and non-diabetic mice presented an additional increased expression of eNos in liver. After 1 week of high fat feeding the liver gene expression pattern was distinct from that seen at 9 months in any of the three mouse groups, thus indicating progressive establishment of the different phenotypes. Strikingly, development of the obese phenotype involved re-expression of Scd-1 and other lipogenic genes. Finally, gene classifiers could be established that were characteristic of each metabolic phenotype. Together, these data suggest that epigenetic mechanisms influence gene expression patterns and metabolic fates.

Injection drug use before and after liver transplantation: a retrospective multicenter analysis on incidence and outcome.

De Gottardi A, Hilleret M-N, Gelez P, La Mura V, Guillaud O, Majno P, Hadengue A, Morel P, Zarski J-P, Fontana M, Moradpour D, Mentha G, Boillot O, Leroy V, Giostra E, Dumortier J. Injection drug use before and after liver transplantation: a retrospective multicenter analysis on incidence and outcome. Clin Transplant 2009 DOI: 10.1111/j.1399-0012.2009.01121.x.Background and aims: Injecting drug use (IDU) before and after liver transplantation (LT) is poorly described. The aim of this study was to quantify relapse and survival in this population and to describe the causes of mortality after LT. Methods: Past injection drug users were identified from the LT listing protocols from four centers in Switzerland and France. Data on survival and relapse were collected and used for uni- and multivariate analysis. Results: Between 1988 and 2006, we identified 59 patients with a past history of IDU. The mean age at transplantation was 42.4 yr and the majority of patients were men (84.7%). The indication for LT was for the vast majority viral cirrhosis accounting for 91.5% of cases, while alcoholic cirrhosis was 5.1%. There were 16.9% of patients who had a substitution therapy before and 6.8% who continued after LT. Two patients (3.4%) relapsed into IDU after LT and died at 18 and 41 months. The mean follow-up was 51 months. Overall survival was 84%, 66%, and 61% at 1, 5, and 10 yr after transplantation. Conclusions: Documented IDU was rare in liver transplanted patients. Past IDU was not associated with poorer survival after LT, and relapse after LT occurred in 3.4%.

Radial forearm free flap donor site morbidity: ulnar-based transposition flap vs split-thickness skin graft.

OBJECTIVES: To evaluate morbidity associated with the radial forearm free flap donor site and to compare functional and aesthetic outcomes of ulnar-based transposition flap (UBTF) vs split-thickness skin graft (STSG) closure of the donor site.¦DESIGN: Case-control study.¦SETTING: Tertiary care institution.¦PATIENTS: The inclusion criteria were flap size not exceeding 30 cm(2), patient availability for a single follow-up visit, and performance of surgery at least 6 months previously. Forty-four patients were included in the study and were reviewed. Twenty-two patients had UBTF closure, and 22 had STSG closure.¦MAIN OUTCOME MEASURES: Variables analyzed included wrist mobility, Michigan Hand Outcomes Questionnaire scores, pinch and grip strength (using a dynamometer), and hand sensitivity (using monofilament testing over the radial nerve distribution). In analyses of operated arms vs nonoperated arms, variables obtained only for the operated arms included Vancouver Scar Scale scores and visual analog scale scores for Aesthetics and Overall Arm Function.¦RESULTS: The mean (SD) wrist extension was significantly better in the UBTF group (56.0° [10.4°] for nonoperated arms and 62.0° [9.7°] for operated arms) than in the STSG group (59.0° [7.1°] for nonoperated arms and 58.4° [12.1°] for operated arms) (P = .02). The improvement in wrist range of motion for the UBTF group approached statistical significance (P = .07). All other variables (Michigan Hand Outcomes Questionnaire scores, pinch and grip strength, hand sensitivity, and visual analog scale scores) were significantly better for nonoperated arms vs operated arms, but no significant differences were observed between the UBTF and STSG groups.¦CONCLUSIONS: The radial forearm free flap donor site carries significant morbidity. Donor site UBTF closure was associated with improved wrist extension and represents an alternative method of closure for small donor site defects.

Requirement of glucose metabolism for regulation of glucose transporter type 2 (GLUT2) gene expression in liver.

Previous studies have shown that glucose increases the glucose transporter (GLUT2) mRNA expression in the liver in vivo and in vitro. Here we report an analysis of the effects of glucose metabolism on GLUT2 gene expression. GLUT2 mRNA accumulation by glucose was not due to stabilization of its transcript but rather was a direct effect on gene transcription. A proximal fragment of the 5' regulatory region of the mouse GLUT2 gene linked to a reporter gene was transiently transfected into liver GLUT2-expressing cells. Glucose stimulated reporter gene expression in these cells, suggesting that glucose-responsive elements were included within the proximal region of the promoter. A dose-dependent effect of glucose on GLUT2 expression was observed over 10 mM glucose irrespective of the hexokinase isozyme (glucokinase K(m) 16 mM; hexokinase I K(m) 0.01 mM) present in the cell type used. This suggests that the correlation between extracellular glucose and GLUT2 mRNA concentrations is simply a reflection of an activation of glucose metabolism. The mediators and the mechanism responsible for this response remain to be determined. In conclusion, glucose metabolism is required for the proper induction of the GLUT2 gene in the liver and this effect is transcriptionally regulated.

L'effet protecteur des protéines alimentaires et l'effet délétère des acides animés alimentaires sur la stéatose hépatique chez la souris [The protective effect of dietary protein and the deleterious effect of dietary amino acids in fatty liver in mice]

Introduction La maladie « Non-Alcoholic Fatty Liver Disease ; NAFLD » et l'obésité provoque la résistance à l'insuline, un symptôme caractéristique du syndrome métabolique. La fréquence de ces maladies a augmenté de manière importante durant ces dernières décennies. Cette augmentation est étroitement liée à la surcharge énergétique dans notre culture modernisée. Pour combattre cette situation, des régimes riches en protéines semblent être bénéfiques, en particulier parce que l'acide aminé leucine stimule la satiété. Cependant l'effet des protéines alimentaires sur la stéatose hépatique reste peu connu. Résultats : Pour étudier cette question, nous avons nourri des souris C57B6/J (âgées de 5 semaines) avec un régime standard (10% kcal graisse, 20% kcal protéine), un régime riche en graisse (45% kcal graisse, 20% kcal protéine) ou un régime riche en graisse et enrichi en protéines (45% kcal graisse, 40% kcal protéine) pendant 10 semaines. Nous avons ainsi montré que l'addition de protéines au régime gras permet de prévenir la stéatose hépatique. Dans un deuxième temps nous avons testé si cet effet bénéfique des protéines alimentaires provient des acides aminés ramifiés (Branched-chain amino acids= BCAA : leucine, isoleucine, valine), composants majeurs de protéines alimentaires. Pour ce faire, nous avons ajouté un groupe de souris nourries au régime riche en graisses + BCAA (45% kcal graisse, 23% kcal protéine). Nos résultats montrent que l'addition des BCAA ne protège pas contre la stéatose hépatique, mais, au contraire, aggrave l'obésité et l'hyperinsulinémie. De manière intéressante, nous avons observé que la supplémentation en protéines ou en BCAA induit des effets différents sur la prise alimentaire et la dépense énergétique. Conclusion : Notre étude suggère clairement que les protéines alimentaires protègent contre l'obésité et la stéatose hépatique. Elle confirme également que les composants majeurs des protéines alimentaires (BCAA) n'exercent pas cet effet protecteur, mais qu'il aggrave le syndrome métabolique. Etant donné que l'ingestion importante et chronique de protéines alimentaires est délétère pour le rein, il serait très intéressant d'identifier les acides aminés spécifiques qui induiraient le même effet protecteur que les protéines alimentaires, mais sans perturber le fonctionnement rénal.

Major Histocompatibility Class II Pathway Is Not Required for the Development of Nonalcoholic Fatty Liver Disease in Mice.

Single-nucleotide polymorphisms within major histocompatibility class II (MHC II) genes have been associated with an increased risk of drug-induced liver injury. However, it has never been addressed whether the MHC II pathway plays an important role in the development of nonalcoholic fatty liver disease, the most common form of liver disease. We used a mouse model that has a complete knockdown of genes in the MHC II pathway (MHCII(Δ/Δ)). Firstly we studied the effect of high-fat diet-induced hepatic inflammation in these mice. Secondly we studied the development of carbon-tetra-chloride- (CCl4-) induced hepatic cirrhosis. After the high-fat diet, both groups developed obesity and hepatic steatosis with a similar degree of hepatic inflammation, suggesting no impact of the knockdown of MHC II on high-fat diet-induced inflammation in mice. In the second study, we confirmed that the CCl4 injection significantly upregulated the MHC II genes in wild-type mice. The CCl4 treatment significantly induced genes related to the fibrosis formation in wild-type mice, whereas this was lower in MHCII(Δ/Δ) mice. The liver histology, however, showed no detectable difference between groups, suggesting that the MHC II pathway is not required for the development of hepatic fibrosis induced by CCl4.

The "reversed" treatment approach for synchronous liver metastases and colorectal cancer. Feasability and first results

Background: The « reversed treatment» approach inverts the treatment sequence of¦advanced synchronous colorectal liver metastases - i.e. the liver metastasis is¦treated first, followed by resection of the primary tumor. Chemotherapy is performed¦before and after liver surgery. We recently started to use a reversed treatment¦approach in selected patients. The aim of this study is to critically assess this new¦treatment modality.¦Methods: Nine patients (7 male, 2 female, mean age 62 years) benefited from this¦new treatment between November 2008 and May 2010. The data were collected¦retrospectively.¦Results: All patients responded to the neoadjuvant chemotherapy. The median¦number of liver metastases was 6 (range 1 - 22). The median size of the largest liver¦metastases was 4.3 cm (range 2.6 - 13 cm). Three patients had portal vein¦embolization prior to liver surgery. Two patients could not complete the treatment.¦One had to undergo emergency surgery for occluding colonic tumor. The second one¦showed liver recurrence before starting the adjuvant chemotherapy. The seven¦patients who completed the treatment are still alive after a median time of 27 months¦(range 17 - 37 months). Seven of them had recurrence (1 rectal, 6 liver). The median¦disease-free survival was 9 months (range 0 - 17 months).¦Conclusion: Based on our preliminary experiences, the reversed strategy shows¦encouraging results for the treatment of advanced synchronous colorectal liver¦metastases in well selected patients. The treatment was generally well tolerated and¦long term survival seems to be prolonged.

Liver kidney microsomal type 1 antibodies reduce the CYP2D6 activity in patients with chronic hepatitis C virus infection.

Liver kidney microsomal type 1 (LKM-1) antibodies have been shown to decrease the CYP2D6 activity in vitro and are present in a minority of patients with chronic hepatitis C infection. We investigated whether LKM-1 antibodies might reduce the CYP2D6 activity in vivo. All patients enrolled in the Swiss Hepatitis C Cohort Study and tested for LKM-1 antibodies were assessed (n = 1723): 10 eligible patients were matched with patients without LKM-1 antibodies. Patients were genotyped for CYP2D6 variants to exclude individuals with a poor metabolizer genotype. CYP2D6 activity was measured by a specific substrate using the dextromethorphan/dextrorphan metabolic ratio to classify patients into four activity phenotypes. All patients had a CYP2D6 extensive metabolizer genotype. The observed phenotype was concordant with the CYP2D6 genotype in most LKM-negative patients, whereas only three LKM-1 positive patients had a concordant phenotype (six presented an intermediate and one a poor metabolizer phenotype). The median DEM/DOR ratio was sixfold higher in LKM-1 positive than in LKM-1 negative patients (0.096 vs. 0.016, P = 0.004), indicating that CYP2D6 metabolic function was significantly reduced in the presence of LKM-1 antibodies. In chronic hepatitis C patients with LKM-1 antibodies, the CYP2D6 metabolic activity was on average reduced by 80%. The impact of LKM-1 antibodies on CYP2D6-mediated drug metabolism pathways warrants further translational studies.

Multiples hyperplasies nodulaires focales hépatiques associées à une agénésie congénitale de la veine porte [Multiple focal nodular hyperplasia of the liver associated with congenital absence of the portal vein]

We report the 32nd case of congenital absence of portal vein in an 18-year-old female adult associated with multiple focal nodular hyperplasia of the liver. The association of various hepatic tumors has been observed in half of the publications about congenital absence of portal vein. Hepatic tumors seem to result from systemic diversion of portal vein flow with a resultant increase of arterial flow causing important vascular and nutritif changes the liver and consequent parenchymal transformation.