The effects of parkin suppression on the behaviour, amyloid processing, and cell survival in APP mutant transgenic mice

Parkin suppression induces accumulation of β-amyloid in mutant tau mice. We studied the effect of parkin suppression on behaviour and brain pathology in APP_swe mutant mice. We produced double mutant mice with human mutated APP_swe + partial (hemizygote) or total (homozygote) deletion of Park-2 gene. We studied the development, behaviour, brain histology, and biochemistry of 12- and 16-month-old animals in 6 groups of mice, with identical genetic background: wild-type (WT), APP_swe overexpressing (APP), hemizygote and homozygote deletion of Park-2 (PK^+/− and PK^−/−, respectively), and double mutants (APP/PK^+/− and APP/PK^−/−).APP mice have reduced weight gain, decreased motor activity, and reduced number of entrances and of arm alternation in the Y-maze, abnormalities which were partially or completely normalized in APP/PK^+/− and APP/PK^−/− mice. The double mutants had similar number of mutant human APP transgene copies than the APP and levels of 40 and 80 kDa proteins; but both of them, APP/PK^+/− and APP/PK^−/− mice, had less plaques in cortex and hippocampus than the APP mice. APP mutant mice had increased apoptosis, proapoptotic Bax/Bcl2 ratios, and gliosis, but these death-promoting factors were normalized in APP/PK^+/− and APP/PK^−/− mice. APP mutant mice had an increased number of tau immunoreactive neuritic plaques in the cerebral cortex as well as increased levels of total and phosphorylated tau protein, and these changes were partially normalized in APP/PK^+/− heterozygotic and homozygotic APP/PK^−/− mice. Compensatory protein-degrading systems such as HSP70, CHIP, and macroautophagy were increased in APP/PK^+/− and APP/PK^−/−. Furthermore, the chymotrypsin- and trypsin-like proteasome activities, decreased in APP mice in comparison with WT, were normalized in the APP/PK^−/− mice.We proposed that partial and total suppression of parkin triggers compensatory mechanisms, such as chaperone overexpression and increased autophagy, which improved the behavioural and cellular phenotype of APP_swe mice.     

Chagas disease reactivation in rheumatologic patients: association with immunosuppressive therapy and humoral response

Clinical Rheumatology - Evidence for Chagas disease reactivation (CDR) in rheumatologic patients under rheumatologic treatments (RTs) is scarce. To screen and follow-up patients with rheumatic...     

Molecular docking to Toxoplasma gondii thymidylate synthase-dihydrofolate reductase and efficacy of raltitrexed in infected mice

Parasitology Research - Toxoplasmosis is a zoonosis of worldwide distribution. Currently, two drugs, pyrimethamine and sulfadiazine, are used as a reference in the treatment of toxoplasmosis, but...     

A proteomic approach to the identification of tegumental proteins of male and female Schistosoma bovis worms

Schistosoma bovis, a parasite of ruminants, can live for years in the bloodstream in spite of the immune response of its host. The parasite tegument covers the entire surface of the worm and plays a key role in the host-parasite relationship. The parasite molecules involved in host immune response evasion mechanisms must be expressed on the tegument surface and are potential targets for immune or drug intervention. The purpose of the present work was to identify the tegumental proteomes of male and female S. bovis worms, in particular the proteins expressed on the outermost layers of the tegument structure. Adult worms of each sex were treated separately with trypsin in order to digest their tegumental proteins, after which the peptides released were analysed by LC-MS/MS for identification. This experimental approach afforded valuable information about the protein composition of the tegument of adult S. bovis worms. A range of tegumental proteins was identified, most of which had not been identified previously in this species. Although an absolute purification of the proteins expressed on the outermost layers of the tegument structure was not achieved, it is likely that present among the proteins identified are some of the molecules most closely associated with the tegument surface. Our study also suggests that there may be differences in the protein composition of the tegument of male and female schistosomes. Finally, the presence of actin and GAPDH on the surface of male and female worms and the presence of enolase exclusively on the surface of male worms were verified by confocal microscopy.     

Inhibition of epidermal growth factor receptor-mediated signaling by "Combi-triazene" BJ2000, a new probe for Combi-Targeting postulates

The Combi-Targeting concept postulates that a molecule termed combi-molecule (C-molecule) with binary epidermal growth factor receptor (EGFR) targeting/DNA-damaging properties and with the ability to be hydrolyzed to another EGFR inhibitor should induce sustained antiproliferative activity in cells overexpressing EGFR. Because we postulate that the EGFR affinity of the C-molecule and that of its hydrolytic metabolites are critical parameters for sustained potency against EGFR-overexpressing cells, we synthesized BJ2000 (IC(50) = 0.1 microM, competitive binding at ATP site), a novel C-molecule that can decompose into a 6-amino-4-anilinoquinazoline FD105 (IC(50) = 0.2 microM). Studies using the EGFR-overexpressing A431 cells revealed that BJ2000 could damage DNA and block epidermal growth factor-stimulated EGFR autophosphorylation by a partially irreversible mechanism. Blockade of EGFR autophosphorylation subsequently induced inhibition of mitogen-activated protein kinase activation and c-fos gene expression. Enzyme-linked immunosorbent assay and growth factor-mediated stimulation of proliferation assays in the EGFR-expressing NIH3T3HER14 demonstrated the preferential EGFR-targeting properties of BJ2000, and more importantly suggest that blockade of EGFR phosphorylation by this drug translate into significant growth inhibitory effects. These properties culminated into irreversible antiproliferative effects as confirmed by a sulforhodamine B assay. Five days after a 2-h treatment, BJ2000 retained significant antiproliferative effect in A431 cells, whereas its reversible metabolite FD105 almost completely lost its activity. This result in toto lend support to the Combi-Targeting concept according to which a molecular conjugate kept small enough to interact with EGFR and designed to degrade into another inhibitor of the same target plus a DNA-damaging species may induce sustained growth inhibitory effect in EGFR-overexpressing cells.     

Miocardiopatia hipocalcémica

The association between hypocalcemia and heart failure is rare. There are few reported cases in the literature of this association, which is termed hypocalcemic cardiomyopathy.We report the case of a 61-year-old woman with no relevant medical history, admitted for progressively worsening exertional dyspnea, orthopnea and edema of the lower limbs for a previous month. Physical examination showed diffuse muscle spasms, with no signs of latent tetany.Further investigation revealed ionized calcium 0.54 mmol/l (normal 1.12-1.30), phosphorus 9.8 mg/dl, parathyroid hormone <2.5 pg/ml and CK >3000 U/l, with normal thyroid function. The electrocardiogram showed long QT interval and a pattern of left ventricular overload, and myocardial biomarkers were negative. The echocardiogram revealed regional wall motion abnormalities, coronary angiography was normal and a cranial CT scan detected calcification of basal ganglia and white matter.She started diuretic and calcium replacement therapy which resulted in complete clinical recovery, with no need for heart failure therapy after normalization of serum calcium.     

Comparison of 2 Canal Preparation Techniques in the Induction of Microcracks: A Pilot Study with Cadaver Mandibles

Introduction

The purpose of this pilot study in a cadaver model was to compare 2 different shaping techniques regarding the induction of dentinal microcracks.

Methods

Three lower incisors from each of 6 adult human cadaver skulls were randomly distributed into 3 groups: the control group (CG, no instrumentation), the GT group (GT Profile hand files; Dentsply Tulsa Dental, Tulsa, OK), and the WO group (WaveOne; Dentsply Tulsa Dental). In the GT group, manual shaping in a crown-down sequence with GT Profile hand files was performed. In the WO group, Primary WaveOne files were used to the working length. Teeth were separated from the mandibles by careful removal of soft tissue and bone under magnification. Roots were sectioned horizontally at 3, 6, and 9 mm from the apex using a low-speed saw. Color photographs at 2 magnifications (25× and 40×) were obtained. Three blinded examiners registered the presence of microcracks (yes/no), extension (incomplete/complete), direction (buccolingual/mesiodistal), and location. Data were analyzed with chi-square tests at P < .05.

Results

Microcracks were found in 50% (CG and GT) and 66% (WO) of teeth at 3 mm, 16.6% (CG) and 33.3% (GT and WO) at 6 mm, and 16.6% in all 3 groups at 9 mm from the apex. There were no significant differences in the incidence of microcracks between all groups at 3 (P = .8), 6 (P = .8), or 9 mm (P = 1). All microcracks were incomplete, started at the pulpal wall, and had a buccolingual direction.

Conclusions

Within the limitations of this pilot study, a relationship between the shaping techniques (GT hand and WaveOne) and the incidence of microcracks could not be shown compared with uninstrumented controls.