Sequence comparison of human and yeast telomeres identifies structurally distinct subtelomeric domains

We have sequenced and compared DNA from the ends of three human chromosomes: 4p, 16p and 22q. In all cases the pro-terminal regions are subdivided by degenerate (TTAGGG)n repeats into distal and proximal sub- domains with entirely different patterns of homology to other chromosome ends. The distal regions contain numerous, short (<2 kb) segments of interrupted homology to many other human telomeric regions. The proximal regions show much longer (approximately 10-40 kb) uninterrupted homology to a few chromosome ends. A comparison of all yeast subtelomeric regions indicates that they too are subdivided by degenerate TTAGGG repeats into distal and proximal sub-domains with similarly different patterns of identity to other non-homologous chromosome ends. Sequence comparisons indicate that the distal and proximal sub-domains do not interact with each other and that they interact quite differently with the corresponding regions on other, non- homologous, chromosomes. These findings suggest that the degenerate TTAGGG repeats identify a previously unrecognized, evolutionarily conserved boundary between remarkably different subtelomeric domains.      

Induction of B cell apoptosis by co-cross-linking CD23 and sIg involves aberrant regulation of c-myc and is inhibited by bcl-2

A novel system to study the effects of co-cross-linking CD23/FceRII and sIg on murine B lymphocytes utilizes a highly multivalent form of anti- Ig prepared by covalently linking anti-Ig antibodies to a DNP-dextran backbone. CD23-sIg co-cross-linking is accomplished by the addition of DNP-specific monoclonal IgE. Previous studies demonstrated that co- cross-linking CD23 and sIg significantly inhibited mouse B cell proliferation, especially at high doses of the multivalent anti-Ig. Interestingly, examination of early activation signals reveals no difference in B cells subjected to co-cross-linking conditions as compared to B cells activated with anti-Ig alone. Total cellular protein tyrosine phosphorylation levels are unchanged by co-cross- linking. Analysis of B cell mRNA reveals that co-cross-linking the receptors does not alter the expression levels of ornithine decarboxylase 8 h after stimulation as compared to the controls. In contrast, levels of the proto-oncogene c-myc were significantly elevated 1 h after inducing B cell activation under co-cross-linking conditions. However, it remains unclear whether this aberrant c-myc regulation plays any role in inducing apoptosis. In addition, on day 3 after stimulation, the co-cross-linking of CD23 and sIg resulted in the formation of apoptotic B cells, determined by both photomicroscopy of the B cell cultures and FACS analysis of B cell nuclei. B cells obtained from bcl-2 transgenic mice proliferated as well as controls, and failed to undergo apoptosis when CD23 and sIg were co-cross-linked on their surface. These studies indicate that co-cross-linking of CD23 with B cell sIg inhibits B cell proliferation by a mechanism that is distinct from that seen by co-cross-linking of the Fc gamma RII and sIg. In addition, these results suggest a means by which antigen- specific IgE can down-regulate additional B cell activation and IgE synthesis.      

Nationwide Implementation of Hello World: A Dutch Email-Based Health Promotion Program for Pregnant Women

Background

In November 2006, an email-based health promotion program for pregnant women was implemented nationally in the Netherlands. The program consisted of emails containing quizzes with pregnancy-related questions tailored to the number of weeks of pregnancy. Emails were sent out once every 4 weeks, up to a maximum of nine emails.

Objectives

The aims of the study were (1) to assess the recruitment of participants and their representativeness of the Dutch population and (2) to study differences in recruitment, program use, and program appreciation among women with different levels of education.

Methods

Data from 13,946 pregnant women who enrolled during the first year of the program were included. Upon registration, participants were asked how they found out about the program and subsequently received an email questionnaire to assess demographic, lifestyle, and Internet characteristics. Program use was tracked, and participants were classified into five user groups (inactive to very active). Program appreciation (low, intermediate, and high) was assessed twice with an email questionnaire that was sent after the woman had received her third and sixth quiz email. Information about pregnant women and their characteristics was obtained from Dutch registries to assess representativeness of the study population.

Results

About 8% of the pregnant women in the Netherlands enrolled in the program. Immigrants were underrepresented, and women with a low level of education seemed to be slightly underrepresented. Most women knew about the program from a promotional email sent by the organization (32%), followed by the Internet (22%) and midwives (16%). Women with little education were more often inactive users of the program than were highly educated women (15% vs 11%, P < .001), whereas highly educated women were more often very active users compared with women with little education (25% vs 20%, P< .001). However, women with less education were more likely than women with more education to have a high appreciation of the program after receiving three quiz emails (52% vs 44%, P = .001).

Conclusions

In this real-life setting, pregnant women can be reached through an email-based health promotion program. Selective engagement by education level remains a challenge.     

BMP Stimulation of Alkaline Phosphatase Activity in Pluripotent Mouse C2C12 Cells is Inhibited by Dermatopontin,One of the Most Abundant Low Molecular Weight Proteins in Demineralized Bone Matrix

Demineralized bone matrix (DBM) is a complex mixture of osteoinductive bone morphogenetic proteins (BMPs), as well as BMP-binding proteins that regulate BMP bioactivity and localization. Our aim was to use modern proteomic methods to identify additional BMP-binding proteins in DBM, with initial emphasis on the most abundant. Relatively large, water-soluble noncollagenous proteins (NCPs) were preferentially extracted from DBM with alkalinized urea. The insoluble residue, which contained the BMP activity, was extracted with GuHCl/CaCl₂, dialyzed versus citrate, defatted, resuspended in GuHCl, dialyzed sequentially against Triton X-100 and water, pelleted, and lyophilized. The proteins in this pellet were fractionated by hydroxyapatite affinity chromatography. Proteins that copurified with BMP bioactivity were separated by SDS-PAGE. Distinct bands were excised, and the proteins in them were reduced and alkylated, digested with trypsin, eluted, and subjected to MALDI/ToF MS (matrix-assisted laser-desorption ionization time-of-flight mass spectrometry). Computer-assisted peptide fingerprint analysis of the MS profiles was used to identify C-terminal lysine-6-oxidase; dermatopontin (DPT); histones H2A2, H2A3, and H2B; and trace amounts of γ-actin. DPT is a 22-kDa, tyrosine-rich acidic matrix protein not previously recognized to be among the most abundant small proteins to copurify with BMP bioactivity in DBM. We tested the effects of DPT on BMP-2 stimulation of alkaline phosphatase (ALP) activity in C2C12 cells. BMP-2 stimulated ALP activity in C2C12 cells by 6.2-fold above basal levels. DPT alone had no effect on ALP activity in C2C12 cells. When added with BMP-2, DPT blocked 40% of the stimulatory effect of BMP-2 on ALP activity in C2C12 cells. DPT is an abundant protein in DBM, and it can inhibit the stimulatory effects of BMP-2 on ALP activity in C2C12 cells.     

Hyperbilirubinemia, hypocarbia and periventricular leukomalacia in preterm infants: relationship to cerebral palsy

This study comprised 103 preterm infants with a gestational age less than 33 weeks who were born in Tampere University Hospital and who were followed up to two years of age. Sixty-four perinatal variables were compared to ultrasound findings in the neonatal period and neurologic handicap at the age of two years. Duration of hypocarbia (PCO2 < or = 30 mmHg) during the first 72 h and hyperbilirubinemia (the mean level of serum total bilirubin) at three days of age were independently and significantly related to periventricular leukomalacia, but not directly to cerebral palsy. The only perinatal variables related independently and significantly to cerebral palsy at two years of age were periventricular leukomalacia and ventriculomegaly. According to these results, periventricular leukomalacia was the main predictor of cerebral palsy in preterm infants. In addition to hypocarbia, hyperbilirubinemia may also be involved in the pathogenesis of extensive (severe cystic) periventricular leukomalacia.     

Magnetic resonance angiography findings in the early post-carotid endarterectomy period

This preliminary study was designed to investigate the ability of multiple axial volume three-dimensional fourier transform (3DFT) time-of-flight (TOF) magnetic resonance angiography (MRA) to depict the carotid bifurcation in the early post-carotid endarterectomy period. Five patients underwent intra-operative digital subtraction angiography (DSA) and carotid MRA within 5 days of carotid endarterectomy. An axial volume fast imaging in steady-state precession (FISP) gradient-echo 3DFT TOF carotid MRA technique in this limited series appeared to display accurately the surgically significant abnormalities at the carotid bifurcation after endarterectomy. However, in normal or near-normal intra-operative DSA studies, overestimation of internal carotid artery stenoses was encountered. Postoperative MRA demonstrates potential as a useful non-invasive investigation after carotid endarterectomy but should be interpreted with caution until larger studies become available.     

Aspergillus endocarditis in chronic granulomatous disease

We report the first case, to our knowledge, of Aspergillus endocarditis in chronic granulomatous disease in a patient who also had an atrial septal defect. A diagnosis was made on culture of the organism from the mass despite extensive prior investigation. The presence of distinctive skin lesions as a diagnostic clue of fungaemia is highlighted. Possible advances in diagnosis by detection of fungal cell wall components and in prophylaxis by use of itraconazole are referred to. We conclude that fungal endocarditis should be considered in this condition, especially in the presence of a structural heart defect.