Cross tolerance between morphine and β-endorphin in vivo

Experiments were performed to establish the development of cross tolerance between morphine and the C-terminal fragment of porcine β-lipotropin /LPH_61–91, β-endorphin/ in rats. Repeated intracerebroventricular /ICV/ or peripheral administration of morphine induced tolerance both to morphine and β-endorphin. The tolerance induced by ICV administration of morphine was more pronounced than in the case of peripheral application. The results give support to the theory that at least in part similar sites and mechanisms are involved in the analgesic activity of morphine and the endorphins.     

Vertical physico-chemical gradients with distinct microbial communities in the hypersaline and heliothermal Lake Ursu (Sovata,Romania)

The effect of vertical physico-chemical stratification on the planktonic microbial community composition of the deep, hypersaline and heliothermal Lake Ursu (Sovata, Romania) was examined in this study. On site and laboratory measurements were performed to determine the physical and chemical variables of the lake water, and culture-based and cultivation-independent techniques were applied to identify the members of microbial communities. The surface of the lake was characterized by a low salinity water layer while the deepest region was extremely saline (up to 300 g/L salinity). Many parameters (e.g. photosynthetically active radiation, dissolved oxygen concentration, pH, redox potential) changed dramatically from 2 to 4 m below the water surface in conjunction with the increasing salinity values. The water temperature reached a maximum at this depth. At around 3 m depth, there was a water layer with high (bacterio) chlorophyll content dominated by Prosthecochloris vibrioformis, a phototrophic green sulfur bacterium. Characteristic microbial communities with various prokaryotic taxa were identified along the different environmental parameters present in the different water layers. Some of these bacteria were known to be heterotrophic and therefore may be involved in the decomposition of lake organic material (e.g. Halomonas, Idiomarina and Pseudoalteromonas) while others in the transformation of sulfur compounds (e.g. Prosthecochloris). Eukaryotic microorganisms identified by molecular methods in the lake water belonged to genera of green algae (Mantionella and Picochlorum), and were restricted mainly to the upper layers.     

Metastatic prostate cancer complicated with chronic disseminated intravascular coagulopathy causing acute renal failure, mimicking thrombotic thrombocytopenic purpura and hemolytic uremic syndrome: pathomechanism, differential diagnosis and therapy related to a case

Disseminated intravascular coagulopathy (DIC) is characterized as activation of the clotting system resulting in fibrin thrombi, gradually diminishing levels of clotting factors with increased risk of bleeding. Basically two types of DIC are distinguished: (1) chronic (compensated) - with alteration of laboratory values and (2) acute (non-compensated) - with severe clinical manifestations: bleeding, shock, acute renal failure (ARF), transient focal neurologic deficit, delirium or coma. Chronic DIC related to metastatic neoplasia is caused by pancreatic, gastric or prostatic carcinoma in most of the cases. Incidence rate of DIC is 13-30% in prostate cancer, among those only 0.4-1.65% of patients had clinical signs and symptoms of DIC. In other words, chronic DIC is developed in one of eight patients with prostate cancer. DIC is considered as a poor prognostic factor in prostatic carcinoma. The similar clinical and laboratory findings of TTP-HUS (thrombotic thrombocytopenic purpura - hemolytic uremic syndrome) and DIC makes it difficult to differentiate between them. A 71 years old male patient with known chronic obstructive pulmonary disease, benign prostatic hyperplasia, significant carotid artery stenosis, gastric ulcer and alcoholic liver disease was admitted to another hospital with melena. Gastroscopy revealed intact gastric mucosa and actually non-bleeding duodenal ulcer covered by clots. Laboratory results showed hyperkalemia, elevated kidney function tests, indirect hyperbilirubinemia, increased liver function tests, leukocytosis, anemia, thrombocytopenia and elevated international normalized ratio (INR). He was treated with saline infusions, four units of red blood cells and one unit of fresh frozen plasma transfusions. Four days later he was transported to our Institution with ARF. Physical examination revealed dyspnoe, petechiae, hemoptoe, oliguria, chest-wall pain and aggressive behavior. Thrombocytopenia, signs of MAHA (fragmentocytes and helmet cells in the peripheral blood), normal INR, elevated lactate dehydrogenase (LDH) and ARF suggested TTP-HUS. Hemodialysis and six plasmaferesis (PF) were carried out. After the fifth PF, skin manifestations of thrombotic microangiopathy occurred on the feet. Clotting analysis revealed elevated D-dimer (>5 μg/mL), normal fibrinogen (3.2 g/L), a slightly raised INR (1.36) and activated partial prothrombin time (APTT) (45.8 sec), normal reticulocyte (57 G/L) and a slightly low platelet count (123 G/L), which proved to be chronic DIC. Therapeutic dose of low-molecular-weight heparin (LMWH) was started. Elevated prostate-specific antigen (PSA) (109.6 ng/mL) suggested prostatic carcinoma. Prostate biopsy revealed adenocarcinoma (Gleason: 4+4 for left lobe and 3+3 for right lobe). Elevated alkaline phosphatase suggested metastases in the bone, which were confirmed by bone scintigraphy. Combined androgen blockade (CAB) was started. After three months follow-up our patient's status is satisfactory. PSA is in the normal range (4.6 ng/mL). Thrombocytopenia of uncertain origin with normal or raised INR, APTT, elevated D-dimer, normal fibrinogen and reticulocyte count prove the diagnosis of chronic DIC. This process warrants searching for metastatic neoplasia. Due to the relatively low serum levels of circulating procoagulant factors (e.g. tissue factor), therapeutic dose of LMWH can be used with good efficiency in chronic DIC with low risk of bleeding. Severe DIC as a complication of metastatic prostate cancer can be treated by androgen deprivation therapy (ADT) or CAB in combination with ketokonazole and concomitant use of supportive treatment. Deme D, Ragán M, Kovács L, Kalmár K, Varga E, Varga T, Rakonczai E. Metastatic prostate cancer complicated with chronic disseminated intravascular coagulopathy causing acute renal failure mimicking thrombotic thrombocytopenic purpura and hemolytic uremic syndrome: pathomechanism, differential diagnosis and therapy related to a case.     

PKCalpha reduces the lipid kinase activity of the p110alpha/p85alpha PI3K through the phosphorylation of the catalytic subunit

The modulation of phosphoinositide 3-kinase (PI3K) activity influences the quality of cellular responses triggered by various receptor tyrosine kinases. Protein kinase C (PKC) has been reported to phosphorylate signalling molecules upstream of PI3K and thereby it may affect the activation of PI3K. Here, we provide the first evidence for a direct effect of a PKC isoenzyme on the activity of PI3K. PKCalpha but not PKCepsilon phosphorylated the catalytic subunit of the p110alpha/p85alpha PI3K in vitro in a manner inhibited by the PKC inhibitor bisindolylmaleimide I (BIM I). The incubation of PI3K with active PKCalpha resulted in a significant decrease in its lipid kinase activity and this effect was also attenuated by BIM I. We conclude that PKCalpha is able to modulate negatively the lipid kinase activity of the p110alpha/p85alpha PI3K through the phosphorylation of the catalytic subunit.     

Partial and full agonism in endomorphin derivatives: comparison by null and operational model

The partial mu-opioid receptor pool inactivation strategy in isolated mouse vas deferens was used to determine partial agonism of endomorphins and their analogs (endomorphin-1-ol, 2',6'-dimethyltyrosine (Dmt)-endomorphin-1, endomorphin-2-ol and (D-Met2)-endomorphin-2) using morphine, normorphine, morphiceptin, (D-Ala2,MePhe4,Gly5-ol)-enkephalin (DAMGO) and its amide (DAMGA) as reference opioid agonists. Agonist affinities (KA) and efficacies were assessed both by the "null" and the "operational" method. The KA values determined by the two methods correlated significantly with each other and also with the displacing potencies against 3H-naloxone in the receptor binding assay in the presence of Na+. DAMGO and DAMGA were full agonist prototypes, morphine, endomorphin-1, endomorphin-1-ol, Dmt-endomorphin-1, endomorphin-2-ol and (D-Met2)-endomorphin-2 were found by both methods to be partial agonists whereas the parameters for normorphine, morphiceptin and endomorphin-2 were intermediate.     

Citrullination: a posttranslational modification in health and disease

Posttranslational modifications are chemical changes to proteins that take place after synthesis. One such modification, peptidylarginine to peptidylcitrulline conversion, catalysed by peptidylarginine deiminases, has recently received significant interest in biomedicine. Introduction of citrulline dramatically changes the structure and function of proteins. It has been implicated in several physiological and pathological processes. Physiological processes include epithelial terminal differentiation, gene expression regulation, and apoptosis. Rheumatoid arthritis, multiple sclerosis, and Alzheimer's disease are examples of human diseases where protein citrullination involvement has been demonstrated. In this review, we discuss our current understanding on the importance of protein deimination in these processes. We describe the enzymes catalyzing the reaction, as well as their known protein substrates. We review the citrullinated peptide epitopes that are proposed as disease markers, specifically recognized in certain human autoimmune disorders. The potential autopathogenic role of citrullinated epitopes is also discussed.     

Investigation of catechol 2,3-dioxygenase and 16S rRNA gene diversity in hypoxic, petroleum hydrocarbon contaminated groundwater

Detection of catechol 2,3-dioxygenase genes in aromatic hydrocarbon contaminated environments gives the opportunity to measure the diversity of bacteria involved in the degradation of the contaminants under aerobic conditions. In this study, we investigated the diversity and distribution of Comamonadaceae family (Betaproteobacteria) related catechol 2,3-dioxygenase genes, which belong to the I.2.C subfamily of extradiol dioxygenase genes. These catabolic genes encode enzymes supposed to function under hypoxic conditions as well, and may play a notable role in BTEX degradation in oxygen limited environments. Therefore, their diversity was analyzed in oxygen limited, petroleum hydrocarbon contaminated groundwater by terminal restriction fragment length polymorphism and cloning. Subfamily I.2.C related catechol 2,3-dioxygenase genes were detected in every investigated groundwater sample and a dynamic change was observed in the case of the structure of C23O gene possessing bacterial communities. To link the metabolic capability to the microbial structure, 16S rRNA gene-based clone libraries were generated and it was concluded that Betaproteobacteria were abundant in the bacterial communities of the contaminated samples. These results support the opinion that Betaproteobacteria may play a significant role in BTEX degradation under hypoxic conditions.     

Overexpression of Hsp27 ameliorates symptoms of Alzheimer's disease in APP/PS1 mice

Hsp27 belongs to the small heat shock protein family, which are ATP-independent chaperones. The most important function of Hsp27 is based on its ability to bind non-native proteins and inhibit the aggregation of incorrectly folded proteins maintaining them in a refolding-competent state. Additionally, it has anti-apoptotic and antioxidant activities. To study the effect of Hsp27 on memory and synaptic functions, amyloid-β (Aβ) accumulation, and neurodegeneration, we generated transgenic mice overexpressing human Hsp27 protein and crossed with APPswe/PS1dE9 mouse strain, a mouse model of Alzheimer's disease (AD). Using different behavioral tests, we found that spatial learning was impaired in AD model mice and was rescued by Hsp27 overexpression. Electrophysiological recordings have revealed that excitability of neurons was significantly increased, and long-term potentiation (LTP) was impaired in AD model mice, whereas they were normalized in Hsp27 overexpressing AD model mice. Using anti-amyloid antibody, we counted significantly less amyloid plaques in the brain of APPswe/PS1dE9/Hsp27 animals compared to AD model mice. These results suggest that overexpression of Hsp27 protein might ameliorate certain symptoms of AD.     

Effect of KRAS mutation status on the efficiency of Avastin therapy of colorectal cancer

Anti-angiogenic therapy became a standard care of advanced colorectal cancer. Since the most frequent genetic alteration of colorectal cancer is KRAS mutation we have analyzed its effect on the efficacy of Avastin treatment. Since 2008 we have determined the KRAS status of 575 patients with colorectal carcinoma using a sensitive screening method and sequencing. In our database the frequency of KRAS mutation in colorectal cancer is 37% (codon 12: 31% followed by codon 13: 6%). We have examined the effect of KRAS status on the efficacy of Avastin treatment in 35 patients. Progression-free survival of KRAS mutant patients was highly similar to that of wild-type patients using log-rank test (9.2+/-5.5 months versus 8.7+/-5.7 months, respectively). Our data support those observations that KRAS status of colorectal cancer does not interfere with the efficacy of Avastin treatment.