Syndiotactic Poly(propylene) from [Me2Si(3,6‐di‐tert‐butyl‐9‐fluorenyl)(N‐tert‐butyl)]TiCl2–Based Catalysts: Chain‐End or Enantiotopic‐Sites Stereocontrol?

The origin of the syndiotactic selectivity in propene polymerization of a typical bridged fluorenyl‐amido catalyst, namely [Me₂Si(3,6‐di‐tert‐butyl‐9‐fluorenyl)(N‐tert‐butyl)]TiCl₂ ( 1 ), activated with methylaluminoxane or [HMe₂N(C₆H₅)][B(C₆F₅)₄]/Al(i‐butyl)₃, was investigated by means of 150 MHz ¹³C NMR spectroscopic microstructural polymer analysis. The asymmetric induction was traced unambiguously to enantiotopic‐sites control. Compared with the better‐known cyclopentadienyl‐fluorenyl ansa‐zirconocenes, 1 turned out to be almost identically enantioselective (in agreement with computer modeling), but less stereoselective because of a higher propensity to undergo site epimerization. This results in a chain microstructure with large predominance of m over mm stereodefects, deceptively similar to that of syndiotactic poly(propylene) produced under chain‐end control.

Methyl region of the 150 MHz ¹³C NMR spectrum of a poly(propylene) sample prepared with catalyst system 1 /borate/TIBAl.     

A 7‐year follow‐up study of the Mindfulness‐Based Program for Infertility: Are there long‐term effects?

The Mindfulness‐Based Program for Infertility (MBPI) was developed for people facing infertility and proved effective in cultivating mindfulness skills, improving infertility self‐efficacy, and decreasing depression, shame, entrapment, and defeat feelings. Fifty‐five women attended the MBPI sessions and completed self‐report measures of depression, anxiety, mindfulness, and experiential avoidance at post‐MBPI (T1), 6‐month follow‐up (T2), and 7‐year follow‐up (T3). There were significant direct time effects regarding experiential avoidance (F = 3.81; p < 0.033; η_p² = 0.08), the mindfulness facets describing (F = 3.54; p = 0.037; η_p² = 0.13), acting with awareness (F = 6.87; p = 0.002; η_p² = 0.22), nonjudging of inner experience (F = 10.66; p < 0.001; η_p² = 0.31), and depressive symptoms (F = 4.85; p = 0.020; η_p² = 0.10). There was an increase in the describing facet from T1 to T3 (p = 0.036). The act with awareness facet increased from T1 to T2 (p = 0.010) and from T1 to T3 (p = 0.007), as well as the nonjudging of inner experience facet (T1 to T2 [p = 0.030] and T1 to T3 [p = 0.002]). Experiential avoidance decreased from T1 to T3 (p = 0.022) and depressive symptoms from T1 to T2 (p = 0.019). Post‐MBPI scores were maintained at T2 and T3 concerning anxiety symptoms and the observing and no‐reactivity mindfulness facets. There were long‐term effects of MBPI on mindfulness and experiential avoidance. Moreover, therapeutic gains were maintained regarding depression and anxiety symptoms, independently of the reproductive outcome.     

Circadian‐ and temperature‐specific effects of early deprivation on rat maternal care and pup development: Short‐term markers for long‐term effects?

We compare the effects on pup body weight and on maternal care of 4-hr separation from dam and littermates on postnatal Days 1 to 14 (early deprivation, ED) under different thermal and circadian conditions. ED was performed at either 21 degrees C (Cold), or 32 degrees C (Warm), and either during the light or dark phase. The comparison group was nonhandling (NH), either under a nonreversed (Light) or reversed (Dark) cycle. At weaning, Cold ED pups were of lower body weight than Warm ED pups, and Warm ED pups were of lower body weight than NH pups. Light and Dark ED pups received high care at reunion relative to NH, and Cold ED pups received higher care at several hours postreunion relative to Warm ED and NH pups. We propose that reduced pup weight and increased maternal care are short-term markers for the severity of Cold ED, and that this manipulation could therefore impact negatively on emotionality and cognition in adulthood.     

c‐erbB‐4/HER4: friend or foe?

The c-erbB-4 receptor has ligand stimulated tyrosine kinase activity but reports differ as to whether it induces cell division or differentiation. There is also controversy regarding its role in breast cancer, with some reports associating overexpression with short survival and others with longer life.     

Are 6‐month‐old foals sensitive to dam's influence?

A recent study has shown that gently handling dams in front of their few days old foals may strongly influence the development of human-foal relationships. In the present study, we test whether 6-month-old foals remain sensitive to their dams' influence. The study was performed on 16 foal-mare dyads, with half of the mares receiving positive contacts from the experimenter in presence of their 6-month-old foals (n = 8) whereas the other mares were not handled (n = 8). All foals were tested 15 and 30-35 days later under various conditions (reaction to a motionless human, approach test, saddle-pad tolerance test). We observe a positive effect of mare' handling on foals' reactions to humans but with a high interindividual variability, suggesting a higher effect of the foals' own behavioral characteristics at this age than at earlier stages.     

Change in hepatitis C virus genotype in hemodialysis patients after end‐of‐treatment response to interferon monotherapy—relapse or re‐infection?

Hepatitis C virus (HCV) infection remains common among hemodialysis patients and its occurrence is related mainly to nosocomial spread. Although dialysis patients with HCV infection respond well to interferon-based therapy, relapse is frequent. This study aimed at a selected group of hemodialysis patients infected with HCV infection undergoing interferon therapy who achieved end-of-treatment virological response but became HCV-RNA positive again 6 months after end-of-treatment. It was evaluated whether de novo HCV-RNA positivity in these non-sustained responders occurred due to lack of clearance of HCV after the initial response to interferon-alpha (relapse) or due to re-infection with a new strain (re-infection). Genotyping by Inno-LiPA and by phylogenetic tree analysis using partial HCV-NS5B sequences at two evaluation points: pre-treatment (T0) and 6 months after end-of-treatment (T18). Non-sustained responders (n = 15) carried subtypes 1a (8 patients), 1b (4 patients), 3a (2 patients), and 4a (1 patient) before treatment. Identical subtypes were detected in 10 patients at T18. Five patients changed genotypes at T18, suggesting nosocomial re-infection. This study emphasizes the importance of epidemiologic measures to control the re-exposure of hemodialysis patients treated previously for HCV infection.     

IL‐17/Th17 in anti‐fungal immunity: What's new?

How the immune system tailors protective responses to suit the infectious challenge while limiting damage to the host is an emerging theme in T‐cell biology. Although many studies have focused on the pathological aspects of IL‐17‐producing T cells in many autoimmune diseases, their role in protective anti‐microbial immunity has also been increasingly recognized. This increased recognition also applies to their role in anti‐fungal immunity; however, the role of IL‐17‐producing T cells in protection versus pathology in fungal infections is still controversial. Although both positive and negative effects on immune resistance have been attributed to the IL‐23/Th17 axis in experimental models of fungal infections, defective Th17 cell differentiation has been linked to recurrent pneumonia by filamentous fungi and the occurrence of mucocutaneous candidiasis in patients with primary immunodeficiencies. Here we discuss how recent findings in experimental candidiasis and aspergillosis shed new lights on the contribution of Th17 cells to resistance and pathology to fungi.     

Synthesis of Novel Monomers and Copolymers from 1‐Vinylpyrrolidin‐2‐one: Attractive Materials for Drug Delivery Systems?

Summary: Polyvinylpyrrolidone (PVP) is a synthetic, non‐toxic, water‐soluble polymer commonly used in a wide range of applications including several pharmaceutical applications. One example of an important application is the controlled release and delivery of therapeutic agents into sites of inflammation or tumours. However, PVP lacks reactive groups, which limits the possibility of adding new functions to the polymer in order to modify its physical and chemical properties. Furthermore, large differences in radical reactivity between 1‐vinylpyrrolidin‐2‐one (NVP) and most other monomers lead to compositional drift during copolymerization. This complicates the introduction of reactive groups into the polymer using this method. Monomers that are derivatives of NVP itself are expected to show smaller differences in radical reactivity and therefore provide a way of preparing PVP with adjustable properties. Here we present the synthesis of five NVP‐based monomers and their use in the preparation of functional PVP with adjustable properties in terms of solubility, loading of functional groups, and molar mass. The results show the possibility of tailoring PVP for different biomedical applications e.g. drug delivery systems.

Copolymers from 1‐vinylpyrrolidin‐2‐one.     

Does MSI‐low exist?

Microsatellite instability is a well-recognised phenomenon. Ten to 15% of sporadic colorectal cancers with a high level of MSI form a well defined group with distinct clinicopathological features. The set of tumours with low level of microsatellite instability (MSI-low), though widely referred to, is not a clearly defined group. The definitions of MSI-low have varied among groups and between different studies from the same group. Some studies have found associations between the MSI-L phenotype and molecular features, notably a higher frequency of K-ras mutations, and, possibly, methylation of methylguanine methyltransferase. Two recent independent studies, however, showed respectively that 68% and 79%, non-MSI-H cancers showed some MSI and could therefore be classed nominally as MSI-L. There was no evidence for a qualitatively discrete MSI-L group, but quantitative differences in the level of MSI were found.     

Three‐year‐old girl with partial trisomy 4p and partial monosomy 8p with resemblance to Brachmann‐de Lange syndrome—another locus for Brachmann‐de Lange syndrome on 4p?

We describe a 3‐year‐old girl with partial trisomy 4p and partial monosomy 8p who had prenatal and postnatal growth retardation, mental retardation, no speech development, mild synophrys, hirsutism, apparently low‐set ears, dysphonic hoarse voice, hyperactivity, and small hands with proximal placement of the thumbs. She had recurrent lung infections, due to earlier aspiration and immune deficiency (chronic granulomatous disease). Cytogenetic findings in this and other cases with suggestive phenotype may point to an additional locus for Brachmann‐de Lange phenotype. Am. J. Med. Genet. 91:180–184, 2000. © 2000 Wiley‐Liss, Inc.