Mislocalization of CDK11/PITSLRE, a regulator of the G2/M phase of the cell cycle, in Alzheimer disease

Post-mitotic neurons are typically terminally differentiated and in a quiescent status. However, in Alzheimer disease (AD), many neurons display ectopic re-expression of cell cycle-related proteins. Cyclin-dependent kinase 11 (CDK11) mRNA produces a 110-kDa protein (CDK11(p110)) throughout the cell cycle, a 58-kDa protein (CDK11(p58)) that is specifically translated from an internal ribosome entry site and expressed only in the G(2)/M phase of the cell cycle, and a 46-kDa protein (CDK11(p46)) that is considered to be apoptosis specific. CDK11 is required for sister chromatid cohesion and the completion of mitosis. In this study, we found that the expression patterns of CDK11 vary such that cytoplasmic CDK11 is increased in AD cellular processes, compared to a pronounced nuclear expression pattern in most controls. We also investigated the effect of amyloid precursor protein (APP) on CDK11 expression in vitro by using M17 cells overexpressing wild-type APP and APP Swedish mutant phenotype and found increased CDK11 expression compared to empty vector. In addition, amyloid-β(25-35) resulted in increased CDK11 in M17 cells. These data suggest that CDK11 may play a vital role in cell cycle re-entry in AD neurons in an APP-dependent manner, thus presenting an intriguing novel function of the APP signaling pathway in AD.     

Evaluation of the DNA damaging effects of amitraz on human lymphocytes in the Comet assay

Amitraz is formamidine pesticide widely used as insecticide and acaricide. In veterinary medicine, amitraz has important uses against ticks, mites and lice on animals. Also, amitraz is used in apiculture to control Varroa destructor. It this study, the alkaline Comet assay was used to evaluate DNA damaging effects of amitraz in human lymphocytes. Isolated human lymphocytes were incubated with varying concentrations of amitraz (0.035, 0.35, 3.5, 35 and 350 μg/mL). The Comet assay demonstrated that all concentrations of amitraz caused statistically significant increase in the level of DNA damage, thus indicating that amitraz possesses genotoxic potential. The concentration of amitraz that produced the highest DNA damage (3.5 μg/mL) was chosen for further analysis with the antioxidant catalase. The obtained results showed that co-treatment with antioxidant catalase (100 IU/mL or 500 IU/mL) significantly reduced the level of DNA damage, indicating the possible involvement of reactive oxygen species in DNA damaging effects of amitraz. Flow cytometric analysis revealed increase of the apoptotic index following treatment with amitraz. However, co-treatment with catalase reduced the apoptotic index, while treatment with catalase alone reduced the percentage of apoptotoc cells even in comparison with the negative control. Therefore, catalase had protective effects against ROS-mediated DNA damage and apoptosis.     

Serum lipid levels in patients with Alzheimer's disease

The role of lipids in the aetiology and progress of Alzheimer's disease (AD) is still unclear High lipid levels could be one of the risk factors for AD, but no association or even protective effects of high cholesterol levels in the development of the AD were also found. The aim of the study was to determine serum levels of total cholesterol, high-density-lipoprotein cholesterol (HDL-C), low-density-lipoprotein cholesterol (LDL-C) and triglycerides (TG) in female patients with AD and in healthy elderly controls. The 50 patients met the diagnostic criteria of probable AD according to the NINDS-ADRDA and DSM-IV criteria. Cognitive impairment was evaluated using the Mini Mental State Examination (MMSE). Patients were subdivided into two groups of 19 patients in the middle (MMSE 10-19) and 31 patients in the late (MMSE 0-9) phase ofAD. Psychotic and non-psychotic features, evaluated by means of Neuropsychiatric Inventory, were presented in 13 and 37patients with AD, respectively. Control group consisted of 58 subjects without cognitive impairment (MMSE >27) and with lipid levels within normal range. Serum lipid levels were determined by the enzymatic colour tests and by the enzymatic clearance assay. Significantly lower lipid levels were found in patients with AD, than in controls. Patients in the late phase of AD had significantly lower entire lipid profile than controls and significantly lower cholesterol and LDL-C levels than patients in the middle stage ofAD. There was no difference in lipid levels between patients with and without psychotic features. The significant positive correlations were found between MMSE scores and cholesterol, LDL-C levels and age in all AD patients. The results support the presumption that lipid profile might be connected with the aetiology and progress of AD and showed the association between low serum cholesterol and LDL-C levels and cognitive decline in patients with AD. Further studies are needed to confirm the relationship between lipid levels and cognition, and to validate the lipid profile as a biological marker for the progress of AD.     

A validation study of appropriate phonological verbal fluency stimulus letters for use with croatian speaking individuals

The aim of this study is to determine the word frequency for all thirty letters of the Croatian alphabet and to collect normative data for the letter fluency task in Croatian speakers. Ninety two healthy participants were given each of the Croatian letters, and asked to generate as many words as possible in 60 seconds for each letter Results suggested that participants generated most frequently words starting with the letters as follows: "K", "P", "S" and "M".     

Sister chromatid exchange and micronuclei in human peripheral blood lymphocytes treated with thyroxine in vitro

Thyroid hormones enhance the metabolic rate and the aerobic metabolism favoring oxidative stress, which is accompanied by induction of damage to cellular macromolecules including the DNA. The aim of the present study was to investigate the ability of thyroxine to induce sister chromatid exchange and micronuclei, and to modulate cell-cycle kinetics in cultured human lymphocytes. Eight experimental concentrations of thyroxine were used, ranging from 2 x 10(-9) to 0.5 x 10(-4)M. Treatment with thyroxine increased the frequency of SCE per cell at the higher concentrations (1.5 x 10(-6), 0.5 x 10(-5), 1.5 x 10(-5) and 0.5 x 10(-4)M). On the other hand, there were no significant aneugenic and/or clastogenic effects observed in the cytokinesis-block micronucleus assay. The results show that thyroxine acted as a relatively weak clastogen compared with the positive control N-methyl-N'-nitro-N-nitrosoguanidine (MNNG). In addition to the genotoxic effects, two high concentrations of thyroxine decreased the mitotic index and caused cell-cycle delay. In conclusion, thyroxine exhibited weak clastogenic effects only at high concentrations. Therefore, effects in humans might appear in cases of acute thyroxine overdose.     

Platelet serotonin and monoamine oxidase in Alzheimer's disease with psychotic features

Post mortem brain studies indicate that alterations in serotonergic and catecholaminergic systems might be associated with Alzheimer's disease (AD). The aim of the study was to determine serotonin (5-HT) levels and monoamine oxidase type B (MAO-B) activity in platelets of psychotic and non-psychotic patients with AD, established according to the NINCDS-ADRDA and DSM-IV-TR criteria. Cognitive impairment and psychotic features were evaluated using Mini Mental Status Examination and Neuropsychiatric Inventory. Platelet 5-HT concentration and MAO-B activity were determined spectrofluorimetrically in 116 (51 male, 65 female) healthy subjects and 70 psychotic (10 male, 60 female) and 151 non-psychotic (32 male, 119 female) patients. Psychotic and non-psychotic female and psychotic male patients had significantly lower platelet 5-HT concentration than corresponding sex matched control subjects. Platelet MAO-B activity was significantly increased in both male and female non-psychotic patients compared to the sex matched controls. Non-psychotic female patients had significantly higher platelet MAO-B activity than psychotic female patients. Our data suggest that platelet MAO-B activity, but not platelet 5-HT concentration, could differentiate between psychotic and non-psychotic subtypes of AD.     

Stimulating effect of sugar dusting on honey bee grooming behaviour

The aim of this research was to investigate whether or not sugar dusting can stimulate the grooming behaviour in Apis mellifera L. (Hymenoptera: Apidae), an important defensive mechanism against Varroa destructor Anderson & Trueman (Acari: Varroidae), and to assess the most effective dose and frequency of treatment. The criterion for evaluation of grooming potential was the percentage of damaged mites (PDM) among the total number collected on the bottom boards of the hives. In each sugar‐treated group PDM was significantly higher in comparison both with the negative control (no treatment) and with the values preceding the treatment. The results point to a stimulating effect of sugar on the grooming behaviour at all doses and frequencies tested. Treatment frequency influenced the stimulating effect of sugar: treatments at 3‐ and 7‐day intervals with 30 and 40 g resulted in significantly higher PDMs than the least frequent treatment (every 14 days); dusting with 20 g influenced PDM only when repeated at 3‐day intervals. Because treatments at 3‐day intervals are time‐consuming, those with 40 or 30 g repeated every 7 days may be recommended. In the positive control (hives treated with amitraz), average PDM was significantly lower than in the negative control and all sugar‐treated groups. Possible causes of the stimulating effect of sugar dusting on bee grooming behaviour are discussed.     

Histomorphometric features of ventral prostate in different aged rats after central ghrelin treatment

Ghrelin, the endogenous ligand of growth hormone secretagogue receptor type 1a (GHS-R1a), has emerged as pleiotropic modulator of diverse biological functions, including energy homeostasis and recently, reproduction. The influence of intracerebroventricularly (ICV) administered ghrelin (1 μg/day/rat for 5 days) to rats of different ages, i.e, peripubertal (38 days), adult (60 days) and middle-aged (180 days) on the ventral prostate size and morphology, serum testosterone levels and testis weight was examined. Ghrelin treatment significantly increased (p < 0.05) absolute ventral prostate weight in peripubertal and middle-aged rats, by 27% and 37% respectively, due to enhancement of epithelial and/or luminal compartment of the gland. In adult rats, both absolute and relative volumes of the acinar lumen were significantly decreased (p < 0.05), by 38% and 44% respectively, which was associated with significant increases (p < 0.05) in relative and absolute volumes of interacinar stroma, whereas ventral prostate weigh was unchanged. Irrespective of animal age, ghrelin did not affect serum testosterone levels. These are the first results of ghrelin treatment effects on healthy prostate appearance, which allow us to conclude that the rat ventral prostate response to ghrelin depends on the developmental stage of animals. Our results merit further investigations and may have clinical implications, especially in the light of data on possible role of ghrelin in prostate hypertrophy and adenomas.     

Premature centromere division of the X chromosome in neurons in Alzheimer's disease

Premature centromere division (PCD) represents a loss of control over the sequential separation and segregation of chromosome centromeres. Although first described in aging women, PCD on the X chromosome (PCD,X) is markedly elevated in peripheral blood lymphocytes of individuals suffering from Alzheimer disease (AD). The present study evaluated PCD,X, using a fluorescent in situ hybridization method, in interphase nuclei of frontal cerebral cortex neurons from sporadic AD patients and age-matched controls. The average frequency of PCD,X in AD patients (8.60 ± 1.20%) was almost three times higher ( p  < 0.01) than in the control group (2.96 ± 1.20). However, consistent with previous studies, no mitotic cells were found in neurons in either AD or control brain, suggesting an intrinsic inability of post-mitotic neurons to divide. In view of the fact that it has been well-documented that neurons in AD can re-enter into the cell division cycle, the findings presented here of increased PCD advance the hypothesis that deregulation of the cell cycle may contribute to neuronal degeneration and subsequent cognitive deficits in AD.     

Protein modeling,molecular network and molecular dynamics study of newly sequenced interleukin-18 (IL-18) gene in Mus musculus

Interleukin-18 (IL-18) belongs to the superfamily of IL-1 protein and exerts a pleiotropic pro-inflammatory effect on the body. Generally, this protein is significantly involved in immune defense during infection in cells, but sometimes its anomalous activities produce some inflammatory diseases like rheumatoid arthritis and Crohn’s disease. In the present study, the IL-18 gene was isolated from mice and was subsequently cloned and sequenced. Further, the network analysis was carried out to explore the functional role of IL-18 protein in animals. The 3D protein structure of the IL-18 protein was generated and docked with appropriate 3-([3-cholamidopropyl]dimethylammonio)-1-propanesulfonate (CPS) ligand. Later the complex structure of the protein was subjected to molecular dynamics simulation (MDS) for 50 ns to determine the effect of ligand on protein. The network analysis explored the correlation of IL-18 protein with others proteins and their involvement in the different significant pathway to defend the cell from various diseases. As confirmed by MDS, the CPS:IL-18 complex was found to be highly stable. Our results further indicated that CPS ligand has the potential to act as a drug molecule, in future, for counteracting IL-18 activity. To date, no structural details were available for animal IL-18. Hence, the finding of this study will be useful in broadening the horizon towards a better understanding of the functional and structural aspects of IL-18 in animals.