Crystallization and Stereocomplexation of PLA-mb-PBS Multi-Block Copolymers.

The crystallization and morphology of PLA-mb-PBS copolymers and their corresponding stereocomplexes were studied. The effect of flexible blocks (i.e., polybutylene succinate, PBS) on the crystallization of the copolymers and stereocomplex formation were investigated using polarized light optical microscopy (PLOM), differential scanning calorimetry (DSC), infrared spectroscopy (FTIR), and carbon-13 nuclear magnetic resonance spectroscopy (13C-NMR). The PLA and PBS multiple blocks were miscible in the melt and in the glassy state. When the PLA-mb-PBS copolymers are cooled from the melt, the PLA component crystallizes first creating superstructures, such as spherulites or axialites, which constitute a template within which the PBS component has to crystallize when the sample is further cooled down. The Avrami theory was able to fit the overall crystallization kinetics of both semi-crystalline components, and the n values for both blocks in all the samples had a correspondence with the superstructural morphology observed by PLOM. Solution mixtures of PLLA-mb-PBS and PLDA-mb-PBS copolymers were prepared, as well as copolymer/homopolymer blends with the aim to study the stereocomplexation of PLLA and PDLA chain segments. A lower amount of stereocomplex formation was observed in copolymer mixtures as compared to neat L100/D100 stereocomplexes. The results show that PBS chain segments perturb the formation of stereocomplexes and this perturbation increases with the amount of PBS in the samples. However, when relatively low amounts of PBS in the copolymer blends are present, the rate of stereocomplex formation is enhanced. This effect dissappears when higher amounts of PBS are present. The stereocomplexation was confirmed by FTIR and solid state 13C-NMR analyses.

Amino acid starvation induces reactivation of silenced transgenes and latent HIV-1 provirus via down-regulation of histone deacetylase 4 (HDAC4).

The epigenetic silencing of exogenous transcriptional units integrated into the genome represents a critical problem both for long-term gene therapy efficacy and for the eradication of latent viral infections. We report here that limitation of essential amino acids, such as methionine and cysteine, causes selective up-regulation of exogenous transgene expression in mammalian cells. Prolonged amino acid deprivation led to significant and reversible increase in the expression levels of stably integrated transgenes transcribed by means of viral or human promoters in HeLa cells. This phenomenon was mediated by epigenetic chromatin modifications, because histone deacetylase (HDAC) inhibitors reproduced starvation-induced transgene up-regulation, and transcriptome analysis, ChIP, and pharmacological and RNAi approaches revealed that a specific class II HDAC, namely HDAC4, plays a critical role in maintaining the silencing of exogenous transgenes. This mechanism was also operational in cells chronically infected with HIV-1, the etiological agent of AIDS, in a latency state. Indeed, both amino acid starvation and pharmacological inhibition of HDAC4 promoted reactivation of HIV-1 transcription and reverse transcriptase activity production in HDAC4(+) ACH-2 T-lymphocytic cells but not in HDAC4(-) U1 promonocytic cells. Thus, amino acid deprivation leads to transcriptional derepression of silenced transgenes, including integrated plasmids and retroviruses, by a process involving inactivation or down-regulation of HDAC4. These findings suggest that selective targeting of HDAC4 might represent a unique strategy for modulating the expression of therapeutic viral vectors, as well as that of integrated HIV-1 proviruses in latent reservoirs without significant cytotoxicity.

An unreported mutation within protein Z gene is associated with very low protein levels in women with fetal loss.

Gene variant intron C G-42A of protein Z is significantly associated with the occurrence of fetal loss. A previously unreported sporadic missense mutation within exon 8 is described in a patient with very low protein Z levels.

Correlation between factors involved in the local haemostasis and angiogenesis in full term human placenta.

INTRODUCTION: Few studies have been carried out to investigate whether distinct areas of full term placenta express different amounts of markers involved in the placental haemostasis and angiogenesis. A possible relationship between the expression of genes involved in the haemostasis and angiogenesis of human placenta has not been investigated. MATERIALS AND METHODS: Twenty-eight fresh human placentas (35-41 weeks of gestation) from uneventful pregnancies were dissected with two different methods. Quantitative mRNA expression of the tissue factor (TF), TF pathway inhibitor (TFPI), TFPI-2, plasminogen activator inhibitor (PAI-2), annexin V (Anx V), vascular endothelial growth factor (VEGF), and thrombomodulin (TM) genes was evaluated by quantitative real time PCR system. Histology of each sample was graded. RESULTS: Gene expression of all the considered markers was not significantly different in each area, using both the different methods of dissection. A significant correlation (p<0.05) was found between the expression of TF and TFPI-2. TF and TFPI-2 were significantly (p<0.05) associated with VEGF, whereas a stronger association (p<0.01) was found between TFPI and TFPI-2. TFPI and TFPI-2 were strongly associated with PAI-2 expression (p<0.01). CONCLUSIONS: In placentas with central cord insertion, gene expression is not dependent on the method of sampling site. A significant relationship between haemostasis and angiogenesis in at term placentas was shown.

Oral anticoagulants: Pharmacogenetics Relationship between genetic and non-genetic factors.

Oral anticoagulants, the main drugs used for the prevention and treatment of thromboembolic diseases, exhibit a greater than 10-fold inter-individual variability in the dose requirement to achieve a therapeutic response. The relationship between the dose prescribed and the individual response is regulated by genetic and environmental factors. In particularly, molecular analysis of two genes, encoding for the enzyme responsible for the warfarin (S)-isoform catabolism (CYP2C9) and for the target enzyme vitamin K epoxide reductase complex 1 (VKORC1), strongly suggested that their genetic variations greatly affect the individual response to oral anticoagulants. Genotype based modelling explained a large amount of dose-variations. As a perspective, it appears meaningful to increase the number of candidate genes involved in the metabolism of oral anticoagulants to set up a powerful tool, easy for a rapid use into all laboratories and clinical settings, to improve the oral anticoagulants therapy management.

A new case of combined factor V and factor VIII deficiency further suggests that the LMAN1 M1T mutation is a frequent cause in Italian patients.

Combined factor V and factor VIII deficiency (F5F8D) is an extremely rare worldwide congenital hemorrhagic disorder that is more prevalent in the Mediterranean area. We report the clinical presentations and the identification of a LMAN1 mutation in a 3-year-old Italian boy who was diagnosed with F5F8D. The mutation identified (M1T) has already been found in several Italian patients. Since the LMAN1 M1T mutation has been identified in most patients with F5F8D, we suggest that the search for this mutation should be the first step in the molecular characterization of patients from an Italian ethnic background.

A polymorphism in the VKORC1 gene is associated with an interindividual variability in the dose-anticoagulant effect of warfarin.

Patients require different warfarin dosages to achieve the target therapeutic anticoagulation. The variability is largely genetically determined, and it can be only partly explained by genetic variability in the cytochrome CYP2C9 locus. In 147 patients followed from the start of anticoagulation with warfarin, we have investigated whether VKORC1 gene mutations have affected doses of drug prescribed to acquire the target anticoagulation intensity. Two synonymous mutations, 129C>T at Cys43 and 3462C>T at Leu120, and 2 missense mutations, Asp38Tyr and Arg151Gln, were identified. None of these mutations was found to affect the interindividual variability of warfarin prescribed. Finally, 2 common polymorphisms were found, 1173C>T in the intron 1 and 3730G>A transition in the 3' untranslated region (UTR). Regardless of the presence of confounding variables, the mean adjusted dose required of warfarin was higher (6.2 mg) among patients with the VKORC1 1173CC genotype than those of patients carrying the CT (4.8 mg; P = .002) or the TT genotype (3.5 mg; P < .001). In the present setting, VKORC1 and CYP2C9 genetic variants investigated accounted for about a third (r2, 0.353) of the interindividual variability. Genetic variants of the VKORC1 gene locus modulate the mean daily dose of drug prescribed to acquire the target anticoagulation intensity.

Polymorphisms in factor II and factor VII genes modulate oral anticoagulation with warfarin.

BACKGROUND AND OBJECTIVES: There is very considerable inter-individual variability in warfarin dosages necessary to achieve target therapeutic anticoagulation. The variability is largely genetically determined but can only partly be explained by genetic variability in the cytochrome CYP2C9 locus. Polymorphisms within the genes coding for vitamin K-dependent proteins have been suggested to predict sensitivity to warfarin therapy. DESIGN AND METHODS: In a cohort of 147 patients followed-up at one specialized clinic from the start of anticoagulation with warfarin, we investigated whether factor II (Thr165Met; G20210A) and factor VII polymorphisms (G-402A; G-401T) affected the doses of warfarin necessary to acquire the target intensity of anticoagulation. RESULTS: Regardless of the presence of confounding variables, the mean adjusted dose of warfarin required was higher among patients with the factor II Thr/Thr 165 genotype (4.2 mg) than among patients carrying the Met165 allele (2.9 mg; p=0.041) and higher in carriers of the factor VII GG-401 genotype (4.1 mg) than in those with the T-401 allele (3.1 mg; p=0.029). No significant effect was found for factor II A20210G and factor VII G-402A polymorphisms. All together, the genetic variants investigated accounted for about a quarter (r2: 0.261) of the inter-individual variability calculated in the present setting. INTERPRETATION AND CONCLUSIONS: Genetic variants of factor II and factor VII modulate the mean daily dose of warfarin required to achieve a target intensity of anticoagulation.