Severe pulmonary hypertension reversed by antibiotics in a patient with Whipple's disease

The case is described of a 58 year old man with systemic Whipple's disease with pericardial and pleural effusions and severe pulmonary hypertension. After three months of antibiotic treatment there was a complete resolution, not only of the symptoms known to be associated with Whipple's disease (diarrhoea, arthralgia, pericardial and pleural effusions), but also of pulmonary hypertension.     

Isothermal crystallization and spherulite structure of partially miscible polypropylene–linear low-density polyethylene blends

Polypropylene (PP) was blended with a linear low-density polyethylene (LLDPE, containing 5% hexene comonomer) over a composition range of 10–90% of PP. The crystallization and morphology of the PP–LLDPE blends were studied by differential scanning calorimetry (DSC), polarized optical microscopy with a hot stage (HSOM), and scanning electron microscopy (SEM). In particular, the isothermal crystallization of PP in molten LLDPE was investigated. It was observed that the crystallization and melting behavior of PP and LLDPE changed in the blends, indicating that there was some degree of miscibility between the PP and the LLDPE. A depression of the equilibrium melting temperature (T) of PP in the blends with no more than 15% of PP confirmed that PP was miscible with LLDPE at and below 15% of PP. In addition, a drastic decrease in T from the 25% PP blend to the 20% blend led us to conclude that the miscible behavior between PP and LLDPE became favorable at a PP concentration of 20%. The optical microscopic images showed that, in the blends with 10 and 15% of PP, the PP crystallized as open-armed diffuse spherulites, similar to those in the miscible blends. In contrast, the PP crystallized in a phase-separated matrix or droplets with more than 25% of PP, when obvious phase separation occurred. The SEM image revealed that the PP lamella was able to penetrate the PP and LLDPE phase boundary and grow in the LLDPE phase. The above results displayed that the PP dissolved in the LLDPE, and, particularly, when the PP concentration was below 20%, the dissolution was substantial. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 628–639, 2001     

Mechanical and thermal properties of toughened polypropylene composites

The mechanical, thermal, and structural properties of a new flexible composite containing polypropylene fiber (PP) in a random poly(propylene‐co‐ethylene) (PPE) matrix with ethylene–propylene elastomer (EP) was investigated with emphasis on the effect of EP elastomer concentration. The intrinsic composition of the composites, toughening of the matrix with EP and the fiber–matrix interface determined the properties of the composites. Through the incorporation of EP elastomer into the polypropylene–poly (propylene‐co‐ethylene) (all‐PP) composite, tensile and storage modulus (E′) decreased, flexural modulus and loss modulus (E″, damping) increased slightly to 0.15 EP and then decreased. There was an increase in impact resistance for the toughened composites, with about 100% increase in comparison with an untoughened all‐PP composite. The composition corresponding to 0.20 weight fraction EP gave optimum impact and mechanical properties. Creep resistance of the composite decreased with increasing EP content, but recovery showed an increase with increasing EP content up to 0.20. Fracture surfaces of composites after impact tests were studied with scanning electron microscopy. Moreover, the use and limitation of theoretical equations to predict the tensile and flexural modulus of the flexible PP composite is discussed. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Structural and Mechanical Properties Changes of Ethylene‐α‐olefin Copolymer Blends Induced by Thermal Treatments and Composition

Summary: Blends of single‐site catalysed ethylene‐α‐butene (C₄VLDPE) and ethylene‐α‐octene (C₈VLDPE) copolymers were prepared by melt extrusion. The phase morphology, thermal and mechanical properties of the blends have been investigated by differential scanning calorimetry (DSC), scanning electron microscopy (SEM), tensile test and dynamic mechanical analysis (DMA). Depending on the composition and thermal history, significant differences in structure and behaviour were found. It was also found that some degree of co‐crystallization occurred for quenched blends; whereas most of the oven slowly cooled blends showed two well‐defined melting peaks, indicating that the slow cooling favoured partial segregation of the fractions with different degrees of branching to form two morphologies. Moreover, SEM revealed morphology of the thinner crystals distributed in‐between the thicker sheaf‐like crystals for the slowly cooled blends with 20–50% C₈VLDPE. Therefore, the synergism in mechanical properties for the blends with 20–50% C₈VLDPE is due to a combination of larger crystal size, more complete phase separation and interfacial interaction produced by the segregation effect of the slow cooling treatment. DMA studies showed that the storage modulus increased as the addition of C₈VLDPE and modulus for the slowly cooled blends are about twice those measured for the quenched ones, indicating higher stiffness of the blends. The smooth shift of β relaxation temperature with addition of C₈VLDPE for both sets of blends confirmed the miscibility in the amorphous phase.

SEM image of the C₄VLDPE‐C₈VLDPE (50/50) blend after oven slow cooling treatment.     

Performance evaluation of canine-associated Bacteroidales assays in a multi-laboratory comparison study

The contribution of fecal pollution from dogs in urbanized areas can be significant and is an often underestimated problem. Microbial source tracking methods (MST) utilizing quantitative PCR of dog-associated gene sequences encoding 16S rRNA of Bacteroidales are a useful tool to estimate these contributions. However, data about the performance of available assays are scarce. The results of a multi-laboratory study testing two assays for the determination of dog-associated Bacteroidales (DogBact and BacCan-UCD) on 64 single and mixed fecal source samples created from pooled fecal samples collected in California are presented here. Standardization of qPCR data treatment lowered inter-laboratory variability of sensitivity and specificity results. Both assays exhibited 100% sensitivity. Normalization methods are presented that eliminated random and confirmed non-target responses. The combination of standardized qPCR data treatment, use of normalization via a non-target specific Bacteroidales assay (GenBac3), and application of threshold criteria improved the calculated specificity significantly for both assays. Such measures would reasonably improve MST data interpretation not only for canine-associated assays, but for all qPCR assays used in identifying and monitoring fecal pollution in the environment.     

Investigation of Trypanothione Reductase as a Drug Target in Trypanosoma brucei

There is an urgent need for new drugs for the treatment of tropical parasitic diseases such as human African trypanosomiasis, which is caused by Trypanosoma brucei. The enzyme trypanothione reductase (TryR) is a potential drug target within these organisms. Herein we report the screening of a 62 000 compound library against T. brucei TryR. Further work was undertaken to optimise potency and selectivity of two novel‐compound series arising from the enzymatic and whole parasite screens and mammalian cell counterscreens. Both of these series, containing either a quinoline or pyrimidinopyrazine scaffold, yielded low micromolar inhibitors of the enzyme and growth of the parasite. The challenges of inhibiting TryR with druglike molecules is discussed.