Prospective analysis of discordant results between biochemical markers and biopsy in patients with chronic hepatitis C

BACKGROUND: The FibroTest and ActiTest are noninvasive biochemical markers of liver injury that are intended for use as alternatives to liver biopsy in patients with chronic hepatitis C. The aims of this study were to assess the quality of biopsy and the prevalence of discordances between biopsy and markers, to identify factors associated with discordances, and to attribute these discordances to either markers or biopsy failure. METHODS: Fibrosis stage and activity grade were prospectively assessed on the same day by a liver biopsy and by markers. On the basis of risk factors for failure and independent endpoints, discordance was classified as being attributable to biopsy or to markers. RESULTS: Only 74 of 537 patients (14%) had a biopsy size > or =25 mm. Discordance was observed in 154 of 537 patients (29%), including 16% for fibrosis staging and 17% for activity grading. Steatosis, an inflammatory profile, and biopsy size were associated with discordance. Discordance was attributable to failure of markers in 13 patients (2.4%) and to biopsy failure in 97 (18%; P <0.001 vs Fibrotest and Actitest), and was nonattributable in 44 patients (8.2%). The most frequent failures attributable to markers were false negatives (1.3%) attributable to inflammation. The most frequent failures attributable to biopsy were false negatives of activity grading (10.1%) and of fibrosis staging (4.5%), both associated with smaller biopsy size and steatosis. False positives of fibrosis staging (3.5%) were associated with fragmented biopsies. CONCLUSION: In this series, the size of liver biopsy is adequate in only a minor proportion (approximately 14%) of patients with chronic hepatitis C. When biopsy and marker results are discordant, a reason can be identified in more than two-thirds of cases and, in those cases, biopsy failure is >7 times more common than diagnostic failure of markers.     

Efficacy and tolerance of a scalp-cooling system for prevention of hair loss and the experience of breast cancer patients treated by adjuvant chemotherapy

The applicability and efficacy of a scalp cooling system were studied in 105 breast cancer patients receiving four cycles of adjuvant chemotherapy with mitoxantrone + cyclophosphamide (NC chemotherapy). Women accepting the scalp-cooling system were compared for alopecia both against those who refused and against a "reference" group of 109 patients similarly treated but without being offered a scalp-cooling system. Hair loss in the 105 study patients was evaluated by nurses using World Health Organization (WHO) criteria at each cycle of chemotherapy. Concomitantly, tolerance and side-effects of the helmet were also recorded in 48 accepting patients. Similarly to reference group patients, a subsample of 27 accepting patients self-assessed hair loss using a specific questionnaire measuring its frequency and severity and the distress associated with this symptom. Nurses' ratings ( n = 105) indicated that hair loss frequency was constantly lower, at each cycle of chemotherapy, in study patients with scalp-cooling system ( n = 77) than in those without ( n = 28). Differences between the two groups were statistically significant at cycles 1 and 3 ( P < 0.05). When compared with those reported by reference group patients ( n = 109), study patients' self-measures of alopecia frequency ( n = 27) provided even more marked results than those achieved by nurses (cycles 1-3: P < 0.01; cycle 4: P < 0.05). Tolerance was generally good and no scalp metastasis was observed among the 77 accepting patients followed up. This study demonstrates that scalp cooling was an effective method of protection against hair loss caused by NC chemotherapy. Its routine use as part of adjuvant chemotherapy, especially in cancers with low prevalences of scalp metastasis, should be seriously considered.     

Evaluation of the Microstat™ sublingual PCO<Subscript>2</Subscript> monitor in ambulatory patients

Physicians often need to measure arterial PCO₂ in clinical practice. Arterial blood gas sampling is typically available only in hospitals and may be unpleasant for patients. Minimally invasive techniques for measuring PCO₂ offer the potential for overcoming these limitations. The MicroStat monitor non-invasively measures PCO₂ in the sublingual tissues, which should track arterial PCO₂ in hemodynamically stable patients. This was a prospective observational study. Patients undergoing routine cardiac catheterization were recruited. Following arterial cannulation, two sequential sublingual PCO₂ measurements were taken and a contemporaneous arterial sample was sent for blood gas analysis. For each subject we calculated the mean sublingual–arterial CO₂ gradient and the test–retest sublingual PCO₂ difference. Twenty-five patients were studied. Mean sublingual–arterial PCO₂ gradient was +6.8 mmHg (95 % limits of agreement ?3.0 to 16.6 mmHg). Test–retest difference was 3.4 mmHg (95 % limits of agreement ?1.1 to 7.9 mmHg), p = 0.11 (Wilcoxon test), repeatability was 11 mmHg. The MicroStat sublingual PCO₂ monitor over-estimates arterial PCO₂ with wide limits of agreement. Test–retest repeatability was poor. Use of sublingual PCO2 monitoring with the MicroStat monitor cannot currently replace blood gas sampling.     

Combination of thermal and cavitation effects to generate deep lesions with an endocavitary applicator using a plane transducer: ex vivo studies

In the high-intensity focused ultrasound (US), or HIFU, field, it is well-known that the cavitation effect can be used to induce lesions of larger volume. The principle is based on the increase in the equivalent attenuation coefficient of the tissue in the presence of the bubbles created by cavitation. The elementary lesions produced by combination of cavitation and thermal effects, using focused transducers, were spherical and developed upstream of the focal point. This paper presents a method that combines cavitation with a thermal effect to obtain deeper lesions using a plane transducer, rather than a focused one. The cavitation effect was produced by delivering intensities of 60 W/cm2 at the face of the transducer for 0.5 s. The applicator was then rotated through 90 degrees at a constant speed of between 0.5 and 1.5 degrees /s. During this rotation, ex vivo tissues were exposed continuously to an acoustic intensity of 14 W/cm2 to combine the cavitation effect with a thermal effect. The necroses were, on average, twice as deep when the cavitation effect was used as those obtained with a thermal effect alone. Observed macroscopically, the lesions have a very well-delimited geometry. Temperature measurements made at different angles of treatment have shown that they were coagulation necroses.     

Ultrasonic signs of pneumothorax: Preliminary work

Ultrasonography is considered to have limited application in respiratory diseases because air reflects sound waves. Twenty-four patients with radiologically confirmed pneumothorax and 100 healthy subjects underwent sonography. In all normal subjects, the hyperechoic pulmonary interface showed respiratory motions termed the “gliding sign” with some comet-tail artifacts. Sonographic signs were shown in all pneumothoraces: disappearance of the gliding sign and no comet tails. The extent of collapse cannot be evaluated, but it is possible to determine its area in partial pneumothorax (N = 5). The follow-up (N = 8) showed the reappearance of the gliding sign. Ultrasonography may be helpful in diagnosing pneumothorax in certain cases. © 1993 John Wiley & Sons, Inc.     

A novel approach for prediction of tacrolimus blood concentration in liver transplantation patients in the intensive care unit through support vector regression

Introduction  

Tacrolimus is an important immunosuppressive drug for organ transplantation patients. It has a narrow therapeutic range, toxic side effects, and a blood concentration with wide intra- and interindividual variability. Hence, it is of the utmost importance to monitor tacrolimus blood concentration, thereby ensuring clinical effect and avoiding toxic side effects. Prediction models for tacrolimus blood concentration can improve clinical care by optimizing monitoring of these concentrations, especially in the initial phase after transplantation during intensive care unit (ICU) stay. This is the first study in the ICU in which support vector machines, as a new data modeling technique, are investigated and tested in their prediction capabilities of tacrolimus blood concentration. Linear support vector regression (SVR) and nonlinear radial basis function (RBF) SVR are compared with multiple linear regression (MLR).     

Expansion of human SCID-repopulating cells under hypoxic conditions

It has been proposed that bone marrow (BM) hematopoietic stem and progenitor cells are distributed along an oxygen (O2) gradient, where stem cells reside in the most hypoxic areas and proliferating progenitors are found in O2-rich areas. However, the effects of hypoxia on human hematopoietic stem cells (HSCs) have not been characterized. Our objective was to evaluate the functional and molecular responses of human BM progenitors and stem cells to hypoxic conditions. BM lineage-negative (Lin-) CD34+CD38- cells were cultured in serum-free medium under 1.5% O2 (hypoxia) or 20% O2 (normoxia) for 4 days. Using limiting dilution analysis, we demonstrate that the absolute number of SCID-repopulating cells (SRCs) increased by 5.8-fold in hypoxic cultures compared with normoxia, and by 4.2-fold compared with freshly isolated Lin-CD34+CD38- cells. The observed increase in BM-repopulating activity was associated with a preferential expansion of Lin-CD34+CD38- cells. We also demonstrate that, in response to hypoxia, hypoxia-inducible factor-1alpha protein was stabilized, surface expression of angiogenic receptors was upregulated, and VEGF secretion increased in BM Lin-CD34+ cultures. The use of low O2 levels to enhance the survival and/or self-renewal of human BM HSCs in vitro represents an important advance and could have valuable clinical implications.     

Peroxynitrite-induced mitochondrial and endonuclease-mediated nuclear DNA damage in acetaminophen hepatotoxicity

Intracellular sources of peroxynitrite formation and potential targets for this powerful oxidant and nitrating agent have not been identified after acetaminophen (AAP) overdose. Therefore, we tested the hypothesis that peroxynitrite generated in mitochondria may be responsible for mitochondrial DNA (mtDNA) and nuclear DNA (nDNA) damage. C3Heb/FeJ mice were treated with 300 mg/kg AAP and monitored for up to 12 h. Loss of mtDNA (assayed by slot blot hybridization) and substantial nDNA fragmentation (evaluated by anti-histone enzyme-linked immunosorbent assay, terminal deoxynucleotidyl transferase dUTP nick-end labeling assay, and agarose gel electrophoresis) were observed as early as 3 h after AAP overdose. Analysis of nitrotyrosine protein adducts in subcellular fractions established that peroxynitrite was generated predominantly in mitochondria beginning at 1 h after AAP injection. Delayed treatment with a bolus dose of glutathione (GSH) accelerated the recovery of mitochondrial glutathione, which then effectively scavenged peroxynitrite. However, mtDNA loss was only partially prevented. Despite the absence of nitrotyrosine adducts in the nucleus after AAP overdose, nDNA damage was almost completely eliminated with GSH administration. A direct comparison of nDNA damage after AAP overdose with nDNA fragmentation during tumor necrosis factor receptor-mediated apoptosis showed similar DNA ladders on agarose gels but quantitatively different results in three other assays. We conclude that peroxynitrite may be partially responsible for mtDNA loss but is not directly involved in nDNA damage. In contrast, nDNA fragmentation after AAP overdose is not caused by caspase-activated DNase but most likely by other intracellular DNase(s), whose activation is dependent on the mitochondrial oxidant stress and peroxynitrite formation.     

Loss of SMARCE1 expression is a specific diagnostic marker of clear cell meningioma: a comprehensive immunophenotypical and molecular analysis

Clear cell meningioma (CCM) is a rare grade II histopathological subtype that usually occurs in young patients and displays high recurrence rate. Germline SMARCE1 mutations have been described in hereditary forms of this disease and more recently in small syndromic and sporadic CCM series. The diagnostic value of SMARCE1 in distinguishing between CCM and other meningioma variants has not been yet established. The aim of our study was to investigate the status of SMARCE1 in a series of CCMs and its morphological mimickers. We compared the performance of an anti‐SMARCE1 antibody and the molecular analysis of the SMARCE1 gene in a retrospective multicenter series of CCMs. All CCMs lossed SMARCE1 immunoexpression. Bi‐allelic inactivating events were found by NGS‐based sequencing in all of these cases, except for one, which was incompletely explored, but had a wild‐type sequence. We then validated the anti‐SMARCE1 antibody specificity by analyzing additional 305 pediatric and adult meningiomas of various subtypes and 15 non‐meningioma clear cell tumors by SMARCE1 immunohistochemistry. A nuclear immunostaining was preserved in all other meningioma variants, as well as non‐meningioma clear cell tumors. In conclusion, our series showed, for the first time, that SMARCE1 immunostaining is a highly sensitive biomarker for CCM, useful as a routine diagnostic biomarker.     

Identification of Ventricular Tachycardia of Epicardial Origin from Unipolar Potentials Obtained at the Endocardial Surface: Is It Feasible?

VT late after myocardial infarction usually originates from the endocardial surface; subepicardial substrates are also possible. The identification of these atypical locations with endocardial mapping remains unresolved even with new mapping technologies. This study compared isopotential maps, signal morphology, and activation patterns around left endocardial breakthroughs recorded in VTs originating from the subepicardium or subendocardium after remote myocardial infarction. These results were extracted from a database of 111 tachycardias obtained at surgery in 34 patients. Mapping was performed with a 128-unipolar electrode system using an epicardial mesh and a left ventricular endocardial balloon. Subepicardial (n = 7) and subendocardial VTs (n = 10) were defined as complete superficial reentry and/or as tachycardias with a > or = 25-ms delay between the earliest activity and the breakthrough of activation on the opposite surface. A positive potential distribution covering the area of initial endocardial activity was observed in a single subepicardial VT but in none of the subendocardial ones (P = NS). R waves were observed on the earliest endocardial unipolar signals in two subepicardial VTs and five subendocardial VTs (P = NS). The area covered by the first 5-ms or 10-ms isochrone at the endocardial level was larger in subepicardial VTs than in subendocardial VTs but the difference was not significant. In conclusion, despite a wider endocardial area of early activity in VTs of subepicardial origin, no reliable criteria can be proposed to identify these tachycardias from mapping data restricted to the endocardial surface. This is probably due to highly nonuniform anisotropic propagation around the scarred tissue.