Bilateral renal tumors; conventional clear cell carcinoma and contralateral t(6;11)/t(X;17)-like tumor Histomorphologic, immunohistochemical, ultrastructural and molecular genetic studies including the report of a novel mutation in the VHL gene

A 34-year-old pregnant woman with bilateral kidney tumors 9.5 and 2.5 cm in maximum diameter is presented. The larger tumor was clear renal cell carcinoma. The smaller contralateral tumor was focally HMB45 positive and had unusual histomorphology, including features resembling clear renal cell carcinoma with features of both t(6;11)- and t(X;17)/ASPL-TFE3 carcinomas. This tumor displayed a complex karyotype. A novel germ line mutation in the VHL gene (c.439A>G/p.I147V) was also identified in this patient.     

Cultivation-dependent plasticity of melanoma phenotype

Malignant melanoma is a highly aggressive tumor with increasing incidence and high mortality. The importance of immunohistochemistry in diagnosis of the primary tumor and in early identification of metastases in lymphatic nodes is enormous; however melanoma phenotype is frequently variable and thus several markers must be employed simultaneously. The purposes of this study are to describe changes of phenotype of malignant melanoma in vitro and in vivo and to investigate whether changes of environmental factors mimicking natural conditions affect the phenotype of melanoma cells and can revert the typical in vitro loss of diagnostic markers. The influence of microenvironment was studied by means of immunocytochemistry on co-cultures of melanoma cells with melanoma-associated fibroblast and/or in conditioned media. The markers typical for melanoma (HMB45, Melan-A, Tyrosinase) were lost in malignant cells isolated from malignant effusion; however, tumor metastases shared identical phenotype with primary tumor (all markers positive). The melanoma cell lines also exerted reduced phenotype in vitro. The only constantly present diagnostic marker observed in our experiment was S100 protein and, in lesser extent, also Nestin. The phenotype loss was reverted under the influence of melanoma-associated fibroblast and/or both types of conditioned media. Loss of some markers of melanoma cell phenotype is not only of diagnostic significance, but it can presumably also contribute to biological behavior of melanoma. The presented study shows how the conditions of cultivation of melanoma cells can influence their phenotype. This observation can have some impact on considerations about the role of microenvironment in tumor biology.     

A specific type of membrane microdomains is involved in the maintenance and translocation of kinase active Lck to lipid rafts

Lck is the principal signal-generating tyrosine kinase of the T cell activation mechanism. We have previously demonstrated that induced Lck activation outside of lipid rafts (LR) results in the rapid translocation of a fraction of Lck to LR. While this translocation predicates the subsequent production of IL-2, the mechanism underpinning this process is unknown. Here, we describe the main attributes of this translocating pool of Lck. Using fractionation of Brij58 lysates, derived from primary naive non-activated CD4(+) T cells, we show that a significant portion of Lck is associated with high molecular weight complexes representing a special type of detergent-resistant membranes (DRMs) of relatively high density and sensitivity to laurylmaltoside, thus called heavy DRMs. TcR/CD4 coaggregation-mediated activation resulted in the redistribution of more than 50% of heavy DRM-associated Lck to LR in a microtubular network-dependent fashion. Remarkably, in non-activated CD4(+) T-cells, only heavy DRM-associated Lck is phosphorylated on its activatory tyrosine 394 and this pool of Lck is found to be membrane confined with CD45 phosphatase. These data are the first to illustrate a lipid microdomain-based mechanism concentrating the preactivated pool of cellular Lck and supporting its high stoichiometry of colocalization with CD45 in CD4(+) T cells. They also provide a new structural framework to assess the mechanism underpinning the compartmentalization of critical signaling elements and regulation of spatio-temporal delivery of Lck function during the T cell proximal signaling.     

Changes in Hemocoagulation in Acute Stroke Patients After One-Hour Sono-Thrombolysis Using a Diagnostic Probe

The aim was to monitor the changes in hemocoagulation parameters in acute ischemic stroke (AIS) patients after sono-thrombolysis of the occluded middle cerebral artery using a duplex transcranial probe with 2.0-MHz frequency in Doppler mode. Sixteen AIS patients indicated for intravenous thrombolysis (IVT) (8 males; mean age 68.3 ± 7.1 y) and 16 AIS patients contraindicated for IVT (11 males; mean age 67.9 ± 7.9 y) were randomized for sono-thrombolysis (8 + 8 patients) or standard treatment (control group) (8 + 8 patients). The significant decrease of plasminogen activator inhibitor-1, plasminogen and α-2-antiplasmin activity by a mean of 60, 32 and 24%, respectively, and the increase of tissue plasminogen activator by a mean of 56% was found after sono-thrombolysis when compared with control group (p < 0.0125); these changes were more evident in patients treated with a combination of sono-thrombolysis and IVT (79, 38, 50 and 82%, respectively) than in patients treated by sono-thrombolysis alone (34, 13, 17 and 30%, respectively). (E-mail: skoloudik@hotmail.com)     

Gait and Balance Impairment after Acute Methanol Poisoning

Neurological sequelae including gait impairment were reported in survivors after methanol intoxication; however, no systematic study has been published so far. We aimed to analyse gait and balance impairment in a group of Czech methanol poisoning survivors. We examined 43 patients (age 46 ± 13 years) 2–8 months after methanol poisoning and 43 healthy controls. Investigations contained a shortened version of Falls Efficacy Scale (FES), clinical tests of gait and balance including Timed Up and Go test (TUG) and gait analysis using GaitRite^® system, neurological and neuropsychological examination, brain imaging, EMG and tests of alcohol consumption. Nineteen patients admitted balance and gait impairment according to FES. Mild to moderate parkinsonian signs showed seven patients. Patients were slower (8.8 versus 5.7 s, p < 0.001) and performed more steps (11.1 versus 7.9, p < 0.001) in TUG compared with the controls. Gait analysis revealed shorter step length (76.5 versus 88.7 cm, p < 0.001), increased double support phase (18.8 versus 15.5%, p < 0.001) and wider base of support (11.3 versus 9.6 cm, p = 0.006) in patients. Eleven patients had deficit of executive function and performed higher cadence compared to the patients with normal execution (122.7 versus 115.0 step/min., p = 0.025). Lower limb polyneuropathy was verified in nine patients, without relation with gait or balance parameters. Neuroimaging revealed lesions mainly in the basal ganglia. Methanol poisoning survivors presented slower wide‐based gait with shortened steps corresponding with frontal gait disorder. Higher stepping cadence associated with executive deficit supported the evidence of frontal lobe dysfunction related to impairment of basal ganglia and connections in frontal cortico‐basal ganglia loops.     

Adherence with perindopril therapy: a pilot study using therapeutic drug monitoring of perindoprilat and an evaluation of the clearance estimation

Background Although measurement of drug serum levels is an objective direct method for testing compliance, it can be distorted by “white-coat compliance” or by variations in drug elimination. Objective The aim of this prospective study was to evaluate the prevalence of noncompliance with perindopril therapy in adult out-patients using pharmacokinetic simulations. The additional aim was to compare the predictive performance of two glomerular filtration rate markers—creatinine and cystatin C. Setting Department of Cardiology, Tomas Bata Regional Hospital in Zlín, Czech Republic. Method Perindoprilat pharmacokinetic models individualized according to patient characteristics were compared with measured perindoprilat serum concentrations to document compliance. Linear regression was used to evaluate the relations between perindoprilat clearance and glomerular filtration rate estimated using creatinine and cystatin C. Main outcome measure Assessment of non-compliance with medication using drug concentration measurements reinforced with therapeutic drug monitoring. Results Non-detectable perindoprilat levels were observed in 26.1% of patients. Another 21.7% were classified as non-compliant based on therapeutic drug monitoring pharmacokinetic simulations. Volume of distribution, clearance and half-life median value (interquarti°range) for perindoprilat were 408.3 (360.4–456.8) L, 10.1 (4.9–17.0) L h^?1 and 24.7 (19.4–62.7) h, respectively. Linear regression models showed tight relationship between cystatin C and perindoprilat clearance. Conclusions Assessment of adherence with medication reinforced with therapeutic drug monitoring and pharmacokinetic simulations is proposed as an optimal method reducing disadvantages of simple drug concentration measurements. Cystatin C proves to be better surrogate marker for perindoprilat elimination than creatinine.