Apoa5 Q139X truncation predisposes to late-onset hyperchylomicronemia due to lipoprotein lipase impairment

While type 1 hyperlipidemia is associated with lipoprotein lipase or apoCII deficiencies, the etiology of type 5 hyperlipidemia remains largely unknown. We explored a new candidate gene, APOA5, for possible causative mutations in a pedigree of late-onset, vertically transmitted hyperchylomicronemia. A heterozygous Q139X mutation in APOA5 was present in both the proband and his affected son but was absent in 200 controls. It was subsequently found in 2 of 140 cases of hyperchylomicronemia. Haplotype analysis suggested the new Q139X as a founder mutation. Family studies showed that 5 of 9 total Q139X carriers had hyperchylomicronemia, 1 patient being homozygote. Severe hypertriglyceridemia in 8 heterozygotes was strictly associated with the presence on the second allele of 1 of 2 previously described triglyceride-raising minor APOA5 haplotypes. Furthermore, ultracentrifugation fraction analysis indicated in carriers an altered association of Apoa5 truncated and WT proteins to lipoproteins, whereas in normal plasma, Apoa5 associated with VLDL and HDL/LDL fractions. APOB100 kinetic studies in 3 severely dyslipidemic patients with Q139X revealed a major impairment of VLDL catabolism. Lipoprotein lipase activity and mass were dramatically reduced in dyslipidemic carriers, leading to severe lipolysis defect. Our observations strongly support in humans a role for APOA5 in lipolysis regulation and in familial hyperchylomicronemia.     

The involvement of the pregnane X receptor in hepatic gene regulation during inflammation in mice

Inflammation and proinflammatory cytokines suppress the expression of several hepatic transporters and metabolic enzymes, often resulting in cholestatic liver disease. However, mechanism(s) of this down-regulation have not been fully elucidated. As the pregnane X receptor (PXR) is involved in inducing many of these hepatic proteins, it is possible that PXR is also involved in their down-regulation during inflammation. Thus, we compared the effect of inflammation on hepatic gene regulation in wild-type (PXR(+/+)) versus PXR-null (PXR(-/-)) mice. Treatment of PXR(+/+) but not PXR(-/-) mice with the PXR activators 5-pregnen-3beta-ol-20-one-16alpha-carbonitrile (PCN) or 17beta-hydroxy-11beta-[4-dimethylamino phenyl]-17alpha-[1-propynyl] estra-4,9-dien-3-one (RU486) resulted in increased mRNA levels of bsep, mdr1a, mrp2, mrp3, oatp2, and cyp3a11, indicating involvement of PXR in their regulation. Significantly lower mRNA levels of bsep, mdr2, mrp2, mrp3, ntcp, oatp2, and cyp3a11 were found in endotoxin-treated PXR(+/+) mice. In endotoxin-treated PXR(-/-) mice, the extent of mrp2 suppression was significantly diminished. Changes in MRP2 expression were supported by Western blot analysis. Although interleukin (IL)-6 imposed significant decreases in the expression of bsep, mrp2, and cyp3a11 in PXR(+/+) mice, this was not observed in PXR(-/-) mice. Of note, significantly lower levels of PXR mRNA and protein were detected in endotoxin- and IL-6-treated PXR(+/+) mice. In addition, endotoxin and IL-6 were also able to suppress PCN-mediated induction of bsep, mrp2, cyp3a11, and PXR. Taken together, our results suggest that PXR plays a role in the down-regulation of several hepatic proteins during inflammation.     

In vitro antiplasmodial properties of Flacourtia flavescens Willd. (Flacourtiaceae) and Rytigynia canthioides (Benth.) Robyns (Rubiaceae)

The present study was conducted to investigate the in vitro antimalarial activity of Flacourtia flavescens Willd. (Flacourtiaceae) and Rytigynia canthioides (Benth.) Robyns (Rubiaceae). These two plants are used in Benin folk medicine to treat malaria and fever. Antimalarial activity was assayed on fresh clinical isolates of chloroquine resistant Plasmodium falciparum using the in vitro semi-microtest. The results revealed that the IC(50) varied from 1.55 to 22.36μg/ml. F. flavescens hydro methanol extract was more active than R. canthioides. The study demonstrated scientific rationale behind the traditional usage of these plants, however further bioactivity guided phytochemical analyses are necessary to identify the active principles.     

Automated image analysis of micronuclei by IMSTAR for biomonitoring

For many years, the analysis of micronuclei (MN) has been successfully applied to human biomonitoring of in vivo genotoxin exposure and provides a sensitive and relatively easy methodology to assess genomic instability. However, there is a need for automation of MN analysis for rapid, more reliable and non-subjective MN detection. In this review, we evaluate the application of automated image analysis of the in vitro cytokinesis-block MN assay on human lymphocytes for human biomonitoring, starting with the requirements that should be fulfilled by a valid and efficient image analysis system. Considering these prerequisites, we compare the automated facility developed in the framework of the European Union-project NewGeneris with other already published systems for automated scoring of MN. Although the automated scoring of MN is now put into place, extension to other cytome assay end points such as apoptosis, necrosis, nuclear buds and nucleoplasmic bridges would greatly enhance the specificity and sensitivity of future biomonitoring studies. Inclusion of these end points would also allow an automated approach to in vitro genotoxicity testing. In addition, automated scoring of the MN assay in exfoliated buccal cells would be very beneficial for large-scale biomonitoring studies, as cells can be collected in a minimally invasive manner.     

Chromatic stability of acrylic resins of artificial eyes submitted to accelerated aging and polishing

Esthetics and durability of materials used to fabricate artificial eyes has been an important eissue since artificial eyes are essential to restore esthetics and function, protect the remaining tissues and help with patients'' psychological therapy. However, these materials are submitted to degrading effects of environmental agents on the physical properties of the acrylic resin.

Objective

This study assessed the color stability of acrylic resins used to fabricate sclera in three basic shades (N1, N2 and N3) when subjected to accelerated aging, mechanical and chemical polishing.

Material and methods

Specimens of each resin were fabricated and submitted to mechanical and chemical polishing. Chromatic analysis was performed before and after accelerated aging through ultraviolet reflection spectrophotometry.

Results

All specimens revealed color alteration following polishing and accelerated aging. The resins presented statistically significant chromatic alteration (p<0.01) between the periods of 252 and 1008 h.

Conclusions

Both polishing methods presented no significant difference between the values of color derivatives of resins.     

Characterization of the molecular fragment that is responsible for agonism of pergolide at serotonin 5-Hydroxytryptamine2B and 5-Hydroxytryptamine2A receptors

Cardiac-valve regurgitation observed in Parkinson patients treated with the ergoline dopamine receptor agonist 8beta-methylthiomethyl-6-propylergoline (pergolide) has been associated with the agonist efficacy of the drug at 5-hydroxytryptamine(2B) (5-HT(2B)) receptors. 5-HT(2A) receptors may also play a role in pergolide-induced cardiac-valve regurgitation. We studied the pharmacological profile of pergolide and eight derivatives in porcine vascular rings endowed with 5-HT(2B) and 5-HT(2A) receptors to detect the molecular fragment of the pergolide molecule that may be responsible for agonism at these receptors. Pergolide derivatives showed a different substitution pattern at N(6), and the side chain at C(8) was modified by replacement of the sulfur against an oxygen atom. We demonstrate that the potent agonism of pergolide both at 5-HT(2B) and 5-HT(2A) receptors is retained when the N(6) propyl substituent is replaced by ethyl. However, agonism can be converted into antagonism if N(6) propyl is replaced by methyl. The N(6)-unsubstituted derivative was a low efficacy 5-HT(2B) receptor partial agonist and a 5-HT(2A) receptor antagonist. This pharmacological pattern was also applicable for pergolide congeners with an oxygen in the side chain at C(8). 6-Methylpergolide retained agonist efficacy and potency compared with pergolide at human (h) D(2LONG(L)) and hD(2SHORT(S)) receptors as determined by guanosine 5'-O-(3-[(35)S]thio)triphosphate binding. Based on the ability of pergolide to produce potent agonism at 5-HT(2B) receptors and the failure of 6-methylpergolide to act as an agonist but as a potent antagonist, we conclude that the N(6) propyl substituent of pergolide is crucial for 5-HT(2B) receptor agonism and thus a determinant of valvular regurgitation.     

Proteasome inhibitor bortezomib impairs both myelofibrosis and osteosclerosis induced by high thrombopoietin levels in mice

Primary myelofibrosis (PMF) is the most serious myeloproliferative disorder, characterized by clonal myeloproliferation associated with cytokine-mediated bone marrow stromal reaction including fibrosis and osteosclerosis. Current drug therapy remains mainly palliative. Because the NF-kappaB pathway is implicated in the abnormal release of cytokines in PMF, the proteasome inhibitor bortezomib might be a potential therapy. To test its effect, we used the lethal murine model of myelofibrosis induced by thrombopoietin (TPO) overexpression. In this TPO(high) model, the development of the disease is related to a deregulated MPL signaling, as recently described in PMF patients. We first demonstrated that bortezomib was able to inhibit TPO-induced NF-kappaB activation in vitro in murine megakaryocytes. It also inhibited NF-kappaB activation in vivo in TPO(high) mice leading to decreased IL-1alpha plasma levels. After 4 weeks of treatment, bortezomib decreased TGF-beta1 levels in marrow fluids and impaired marrow and spleen fibrosis development. After 12 weeks of treatment, bortezomib also impaired osteosclerosis development through osteoprotegerin inhibition. Moreover, this drug reduced myeloproliferation induced by high TPO level. Finally, bortezomib dramatically improved TPO(high) mouse survival (89% vs 8% at week 52). We conclude that bortezomib appears as a promising therapy for future treatment of PMF patients.     

N-substituted tetrahydro-2,4-dioxoquinazolin-1-yl acetic acids as aldose reductase inhibitors

Novel N-substituted tetrahydro-2,4-dioxoquinazolin-1-yl acetic acids characterized by formal replacement of the substituted benzyl moiety by cyclohexylmethyl and n-heptyl residues, respectively, were synthesized and evaluated as aldose reductase inhibitors.