Benign vascular proliferation in a lymph node following acute toxoplasmosis. A differential diagnosis from Kaposi's sarcoma

We describe an unusual intranodal vascular proliferation following acute toxoplasmosis in a man. This proliferation is distinct from other benign vasoformative nodal lesions. It could be interpreted as a reactive healing process that might be misdiagnosed as nodal Kaposi's sarcoma. Some criteria to avoid such misdiagnosis are presented.     

Formalin-fixed and paraffin-embedded nodal non-Hodgkin's lymphomas demonstrate the same chromosome changes as those found in frozen samples: a comparative study using interphase fluorescence in situ hybridization.

Cytogenetic studies in lymphomas classically require fresh or frozen tissue, whereas in many instances only paraffin-embedded biopsies are available. We applied an interphase FISH assay on nuclei extracted from thick paraffin sections to determine accuracy of molecular cytogenetics in such samples. Twenty-three lymphoma samples and 4 reactive lymph nodes were tested with various commercially available DNA probes, and hybridization patterns were compared with those obtained on frozen nuclei counterparts. Successful hybridization with all probes tested was observed for 23/27 (85%) paraffin-embedded tissues and for all (100%) frozen samples, and cut-off levels defining positivity were superimposable for both situations. Chromosome changes were detected in the same way, without any false-positive or false-negative cases. Hybridization signals observed on dewaxed samples were either those classically expected to define the relevant chromosome change or were atypical: all atypical changes could be demonstrated also into nuclei from the frozen counterpart. Moreover, all typical and atypical chromosome changes observed on frozen nuclei were also detected in paraffin-embedded tissues. Our study shows that our interphase FISH assay performed on paraffin-embedded samples is a valuable alternate to conventional methods to ascertain diagnosis of lymphomas as to include patients into therapeutic trials.     

Acral myxoinflammatory fibroblastic sarcoma: a report of two cases

Acral myxoinflammatory fibroblastic sarcoma is a rare low-grade malignant soft tissue tumor, usually observed in the extremities of middle-aged adults. We report two cases which occurred in the thumb and knee of middle-aged women. Both tumors showed a multinodular architecture, with cellular areas, occasional foci of hyalinized fibrosis, and hypocellular areas with a myxoid background. Various neoplastic cells were identified including spindled or rounded epithelioid cells and occasional bizarre giant cells, morphologically mimicking Reed-Sternberg cells or ganglion cells. Tumor cells were strongly immunoreactive for vimentin, and variably positive for CD68 and CD34. Both tumors were completely resected and patients were free of disease without any further treatment after a mean follow-up of 14 months.     

Impact of front line relative dose intensity for methotrexate and comorbidities in immunocompetent elderly patients with primary central nervous system lymphoma

Primary central nervous system lymphomas (PCNSL) are non-Hodgkin lymphomas strictly localized to the CNS, occurring mainly in elderly patients with comorbidities. Current treatment in fit patients relies on high-dose methotrexate and high-dose cytarabine. The aim of this study was to evaluate the efficacy and feasibility of this treatment in elderly patients and to assess potential prognostic factors associated with survival. We conducted a retrospective study in two centers between January 2008 and September 2015 including 35 elderly immunocompetent patients who received first-line treatment with high-dose methotrexate. With a median follow-up of 19.8 months (range: 1.7–73.4 months), median overall survival (OS) was 39.5 months (95% confidence interval (95% CI): 18.3–60.7) and median progression-free survival (PFS) was 25.8 months (95% CI: 5.2–46.4). In univariate analysis, administration of high-dose cytarabine and achieving a relative dose intensity for methotrexate >?75% were associated with increased OS (p?=?0.006 and p?=?0.003, respectively) and PFS (p?=?0.003 and p?=?0.04, respectively) whereas comorbidities, defined by a CIRS-G score ≥?8, were associated with decreased OS and PFS (p?=?0.02 and p?=?0.04, respectively). A high MSKCC score was associated with decreased OS (p?=?0.02). In multivariate analysis, administration of high-dose cytarabine was associated with increased OS and PFS (p?=?0.02 and p?=?0.007, respectively). Comorbidities and relative dose intensity for methotrexate are important for the prognosis of elderly patients with PCNSL. These results must be confirmed in prospective trials.     

Precise evaluation of liver histology by computerized morphometry shows that steatosis influences liver stiffness measured by transient elastography in chronic hepatitis C

Background

Liver stiffness evaluation (LSE) by Fibroscan is now widely used to assess liver fibrosis in chronic hepatitis C. Liver steatosis is a common lesion in chronic hepatitis C as in other chronic liver diseases, but its influence on LSE remains unclear. We aimed to precisely determine the influence of steatosis on LSE by using quantitative and precise morphometric measurements of liver histology.

Methods

650 patients with chronic hepatitis C, liver biopsy, and LSE were included. Liver specimens were evaluated by optical analysis (Metavir F and A, steatosis grading) and by computerized morphometry to determine the area (%, reflecting quantity) and fractal dimension (FD, reflecting architecture) of liver fibrosis and steatosis.

Results

The relationships between LSE and liver histology were better described using morphometry. LSE median was independently linked to fibrosis (area or FD), steatosis (area or FD), activity (serum AST), and IQR/LSE median. Steatosis area ≥4.0 % induced a 50 % increase in LSE result in patients with fibrosis area <9 %. In patients with IQR/LSE median ≤0.30, the rate of F0/1 patients misclassified as F ≥ 2 by Fibroscan was, respectively for steatosis area <4.0 and ≥4.0 %: 12.6 vs 32.4 % (p = 0.003). Steatosis level did not influence LSE median when fibrosis area was ≥9 %, and consequently did not increase the rate of F ≤ 3 patients misclassified as cirrhotic.

Conclusion

A precise evaluation of liver histology by computerized morphometry shows that liver stiffness measured by Fibroscan is linked to liver fibrosis, activity, and also steatosis. High level of steatosis induces misevaluation of liver fibrosis by Fibroscan.     

Diagnosis of different liver fibrosis characteristics by blood tests in non‐alcoholic fatty liver disease

Aims: Our aim was to develop an accurate, non‐invasive, blood‐test‐based method for identifying the main characteristics of liver fibrosis in non‐alcoholic fatty liver disease (NAFLD). Methods: Fibrosis was staged according to NASH‐CRN and Metavir systems in 226 patients with NAFLD. A fully automated algorithm measured the fractal dimension (FD) and the area of fibrosis (AOF). Independent predictors of diagnostic targets were determined using bootstrap methods. Results: (i) Development. Significant fibrosis defined by NASH‐CRN F≥2 was diagnosed by weight, glycaemia, aspartate aminotransferase (AST), alanine aminotransferase (ALT) and prothrombin index [area under the receiver operating characteristic (AUROC)=0.867]; significant fibrosis defined by Metavir F≥2 was diagnosed by weight, age, glycaemia, AST, ALT, ferritin and platelets (FibroMeter AUROC=0.941, P<0.005). AOF was estimated by the combination of hyaluronic acid, glycaemia, AST, ALT, platelets and prothrombin index (_aR²=0.530), while FD was estimated by hyaluronic acid, glycaemia, AST/ALT, weight and platelets (_aR²=0.529). (ii) Evaluation. Although NASH‐CRN was a better system for fibrosis staging, Metavir staging was a better reference for blood test. Thus, the patient rate with predictive values≥90% by tests was 97.3% with Metavir reference vs. 66.5% with NASH‐CRN reference (P<10^?3). FibroMeter showed a significantly higher AUROC than the NAFLD fibrosis score for significant fibrosis, but not for severe fibrosis or cirrhosis, with both staging systems. Relationships between fibrosis lesions were well reflected by blood tests, e.g., the correlation between histological area and FD of fibrosis (r_s=0.971, P<10^?3) was well reflected by the relationship between respective blood tests (r_s=0.852, P<10^?3). Conclusions: Different characteristics of fibrosis in NAFLD can be diagnosed and quantified by blood tests with excellent accuracy.     

Role of TNF-alpha receptors in mice intoxicated with the parkinsonian toxin MPTP

Local application of GABA-potentiating agents can prevent or reduce the development and maintenance of behavioral seizures induced by limbic kindling in rats. Microinjection and lesion studies suggest that the transition zone between anterior and posterior piriform cortex (PC), termed here central PC, is a potential target for transplantation of GABA-producing cells. In the present study, we transplanted conditionally immortalized mouse cortical neurons, engineered with the GABA-synthesizing enzyme GAD(65), to the central PC of rats. Suspensions of 1.5 x 10(5) cells in 1 microl were transplanted bilaterally. Control animals received transplantation of beta-galactosidase (beta-gal)-expressing cells. All rats were subsequently kindled through a chronically implanted electrode placed in the basolateral amygdala. The pre- and postkindling threshold currents for eliciting behavioral seizures were determined before and after kindling. We found the prekindling partial seizure threshold to be significantly increased by about 200% in the rats that received the GABA-producing cells compared to rats receiving beta-gal-producing transplants. After kindling, the seizure threshold tended to be higher by 100% in rats that received GABA-producing cells, although the difference from controls was not statistically significant. GABA-producing transplants had no significant effect on the rate of amygdala kindling, but the latency to the first generalized seizure during kindling was significantly increased in animals receiving GABA-producing cells. The transplanted cells showed long-term GAD(65) expression as verified immunohistologically after termination of the experiments. The findings substantiate and extend previous findings that the central PC is part of the anatomical substrate that facilitates propagation from partial to generalized seizures. The data demonstrate that genetically engineered cells have the potential to raise seizure thresholds when transplanted to the central PC.     

Animal and human faces in natural scenes: How specific to human faces is the N170 ERP component?

The N170 is an event-related potential component reported to be very sensitive to human face stimuli. This study investigated the specificity of the N170, as well as its sensitivity to inversion and task status when subjects had to categorize either human or animal faces in the context of upright and inverted natural scenes. A conspicuous N170 was recorded for both face categories. Pictures of animal faces were associated with a N170 of similar amplitude compared to pictures of human faces, but with delayed peak latency. Picture inversion enhanced N170 amplitude for human faces and delayed its peak for both human and animal faces. Finally, whether processed as targets or non-targets, depending on the task, both human and animal face N170 were identical. Thus, human faces in natural scenes elicit a clear but non-specific N170 that is not modulated by task status. What appears to be specific to human faces is the strength of the inversion effect.     

Inhibition of tumorigenicity and metastasis of human melanoma cells by anti-cathepsin L single chain variable fragment

We demonstrated previously that the switch from nonmetastatic to highly metastatic phenotype of human melanoma cells is directly related to secretion of procathepsin L form. This cysteine proteinase was identified on the basis of its property to cleave human C3, the third component of complement. In an attempt to control procathepsin L secretion, we have recently generated an anti-cathepsin L single chain variable fragment (ScFv) from an anti-cathepsin L monoclonal antibody generated against recombinant cathepsin L. We herein selected clones stably transfected with this anti-cathepsin L ScFv and analyzed them for changes in tumor growth and metastasis. We show that in stably transfected clones, anti-cathepsin L ScFv strongly inhibited the secretion of procathepsin L without modifying the intracellular amount or processing pattern of cathepsin L forms. Confocal analysis demonstrated colocalization of endogenous cathepsin L and anti-cathepsin L ScFv. In addition, expression of this ScFv strongly inhibited generation of tumor and metastasis by these human melanoma clones in nude mice. In vivo, the anti-cathepsin L ScFv-transfected cells produced tumors with decreased vascularization (angiogenesis) concomitant with increased apoptosis of tumor cells. Matrigel assay also demonstrated that melanoma invasiveness was completely abolished. Thus, this is the first demonstration that anti-cathepsin L ScFv could be used to inhibit the tumorigenic and metastatic phenotype of human melanoma, depending on procathepsin L secretion, and could therefore be used as a molecular tool in a therapeutic cellular approach.