Isotope effect on adsorbed quantum phases: diffusion of H2 and D2 in nanoporous carbon.

Quasielastic neutron scattering of H(2) and D(2) in the same nanoporous carbon at 10-40 K demonstrates extreme quantum sieving, with D(2) diffusing up to 76 times faster. D(2) also shows liquidlike diffusion while H(2) exhibits Chudley-Elliott jump diffusion, evidence of their different relationships with the local lattice of adsorption sites due to quantum effects on intermolecular interactions. The onset of diffusion occurs at 22-25 K for H(2) and 10-13 K for D(2). At these temperatures, H(2) and D(2) have identical thermal de Broglie wavelengths that correlate with the dominant pore size.

Resident Research in Emergency Medicine: An Introduction and Primer.

Training in research methodology represents an important aspect of emergency medicine (EM) resident education, but best methods for design, implementation, and dissemination of resident research remain elusive. Here we describe recommendations and best practices from the existing literature on EM resident research, including helpful tips on how to best implement a resident research program.

Comparison of outcomes of permanently closed and periodically harvested coral reef reserves.

In many areas of the developing world, the establishment of permanent marine reserves is inhibited by cultural norms or socioeconomic pressures. Community conserved areas that are periodically harvested are increasingly being implemented as fisheries management tools, but few researchers have empirically compared them with permanently closed reserves. We used a hierarchical control-impact experimental design to compare the abundance and biomass of reef fishes, invertebrates, and substrate composition in periodically harvested and permanent reserves and in openly fished (control sites) of the South Pacific island country of Vanuatu. Fished species had significantly higher biomass in periodically harvested reserves than in adjacent openly fished areas. We did not detect differences in substratum composition between permanent reserves and openly fished areas or between permanent reserves and periodically harvested reserves. Giant clams (tridacnids) and top shells (Trochus niloticus) were vulnerable to periodic harvest, and we suggest that for adequate management of these species, periodically harvested community conservation areas be used in conjunction with other management strategies. Periodic harvest within reserves is an example of adaptive and flexible management that may meet conservation goals and that is suited to the social, economic, and cultural contexts of many coastal communities in the developing world.

Efficacy and safety of simoctocog alfa (Nuwiq®) in patients with severe hemophilia A: a review of clinical trial data from the GENA program.

Simoctocog alfa (human-cl rhFVIII, Nuwiq®) is a 4th generation recombinant FVIII (rFVIII), without chemical modification or fusion with any other protein/fragment. Nuwiq® is produced in a human embryonic kidney cell line (HEK293F), which ensures human-specific post-translational protein processing. Nuwiq® was evaluated in seven prospective clinical studies in 201 adult and pediatric previously treated patients (PTPs) with severe hemophilia A. The NuProtect study in 110 previously untreated patients (PUPs) is ongoing. The mean half-life of Nuwiq® was 15.1-17.1 h in PTP studies with adults and adolescents, and 12.5 h in children aged 2-12 years. Clinical trials in PTPs demonstrated the efficacy and safety of Nuwiq® in the prevention and treatment of bleeds and as surgical prophylaxis. In the NuPreviq study of pharmacokinetic (PK)-guided personalized prophylaxis in 66 adult PTPs, 83% of patients had no spontaneous bleeds during 6 months of personalized prophylaxis and 57% were treated ⩽2 per week. No FVIII inhibitors were detected in PTPs after treatment with 43,267 injections and >80 million IU of Nuwiq®. Interim data for 66 PUPs with ⩾20 exposure days to Nuwiq® in NuProtect demonstrated a low cumulative high-titer inhibitor rate of 12.8% [actual incidence 12.1% (8/66)] and convincing efficacy and safety.

Fascicular multiple ocular motor nerve paresis as first presentation of anaplastic astrocytoma.

A case of spontaneous, painless partial III (pupil-sparing) and IV fascicular nerve paresis as the first presentation of anaplastic astrocytoma is reported. The other ocular, neurological and systemic examination was within normal limits. The literature and possible anatomical location of this atypical presentation is reviewed.

Phase Transition of H2 in Subnanometer Pores Observed at 75 K.

Here we report a phase transition in H2 adsorbed in a locally graphitic Saran carbon with subnanometer pores 0.5-0.65 nm in width, in which two layers of hydrogen can just barely squeeze, provided they pack tightly. The phase transition is observed at 75 K, temperatures far higher than other systems in which an adsorbent is known to increase phase transition temperatures: for instance, H2 melts at 14 K in the bulk, but at 20 K on graphite because the solid H2 is stabilized by the surface structure. Here we observe a transition at 75 K and 77-200 bar: from a low-temperature, low-density phase to a high-temperature, higher density phase. We model the low-density phase as a monolayer commensurate solid composed mostly of para-H2 (the ground nuclear spin state, S = 0) and the high-density phase as an orientationally ordered bilayer commensurate solid composed mostly of ortho-H2 (S = 1). We attribute the increase in density with temperature to the fact that the oblong ortho-H2 can pack more densely. The transition is observed using two experiments. The high-density phase is associated with an increase in neutron backscatter by a factor of 7.0 ± 0.1. Normally, hydrogen produces no backscatter (scattering angle >90°). This backscatter appears along with a discontinuous increase in the excitation mass from 1.2 amu to 21.0 ± 2.3 amu, which we associate with collective nuclear spin excitations in the orientationally ordered phase. Film densities were measured using hydrogen adsorption. No phase transition was observed in H2 adsorbed in control activated carbon materials.

Identification of HIV-1 envelope glycoprotein in the serum of AIDS and ARC patients.

Binding of the human immunodeficiency virus type 1 (HIV-1) external envelope glycoprotein (gp120) has been reported to alter the function and surface antigen expression of lymphocytes and monocytes in vitro. To determine whether these in vitro findings could be relevant in vivo, we searched for the presence of this antigen in the serum of patients with AIDS and the AIDS-related complex (ARC). Using an antigen capture enzyme-linked immunosorbent assay (ELISA) with polyclonal anti-gp120 antibody, we detected envelope antigens (gp160/120) in serum of 22 of 32 AIDS patients. In contrast, an ELISA using solid-phase recombinant CD4 to capture gp160/120 failed to detect any positives. A modification of the anti-gp120-based ELISA identified gp160/120-IgG immune complexes in all of 11 AIDS patients tested and in 4 ARC patients who were negative for gp160/120 antigen. We conclude that gp160/120, predominantly in the form of immune complexes, can be identified as circulating antigen in patients with AIDS. The potential pathogenic consequences of this antigenemia, its relation to soluble CD4 therapy, and its application as a clinical marker of disease merit further study.

Obesity as a cause of mechanical entropion.

PURPOSE: Although lower eyelid entropion can result from many conditions, obesity is not a generally recognized factor. We treated a case of recurrent severe entropion that was a result of morbid obesity in a patient with de Morsier's syndrome. METHODS: The patient underwent surgery on both lower eyelids. RESULTS: The entropion was corrected by advancing the lower eyelid retractors and debulking the subcutaneous tissue in the lower eyelids. CONCLUSIONS: Mechanical entropion can occur as a rare complication of morbid obesity and may respond to surgical procedures that address its cause.

A comparison of Wright card with Teller card for detection of amblyopia.

PURPOSE: Teller acuity cards are used to assess visual acuity in infants but can underestimate amblyopia. In order to improve amblyopia detection, a new luminance balanced checkered card of 4.8 cycles/cm frequency was developed by Wright and Vistech (Dayton, Ohio). The Wright card was compared with a corresponding Teller card (of 4.8 cycles/cm) for detection of amblyopia. METHODS: A prospective masked study of 44 children was carried out. Each was assessed for amblyopia using both the Wright and Teller cards in addition to the Snellen or Allen card (optotype). The results were analyzed statistically using repeated measures of ordinal data. RESULTS: Thirteen eyes were found to be amblyopic with optotype testing, two with the Teller card and 17 with the Wright card. With optotype acuity as the standard, the sensitivity and specificity of the Teller card was 15.3% and 100%, while that of the Wright card was 100% and 94.6%. DISCUSSION: The Teller card is associated with high false negative test rate because it assesses grating acuity and allows spurious resolution possibly due to an edge artifact. This artifact is less pronounced with the Wright card. Further, the stripes on the Teller card require resolution only in horizontal axis, while the checkers requires uniform resolution in all axes. Different pathways for neural processing may also contribute to the disparate results with these methods. CONCLUSIONS: The Wright card was more sensitive than the Teller card for the detection of amblyopia in this study population and has potential value in preverbal children.

Anti-TNFα domain antibody construct CEP-37247: Full antibody functionality at half the size.

We report preclinical data for CEP-37247, the first human framework domain antibody construct to enter the clinic. At approximately 11 - 13kDa, domain antibodies or dAbs are the smallest antibody domain able to demonstrate the antigen-recognition function of an antibody, e.g. high selectivity and affinity for target antigen. CEP-37247 is a bivalent anti-tumor necrosis factor (TNF)α domain antibody protein construct combining the antigen-recognition function of a dAb with the pharmacological advantages of an antibody Fc region. As a homodimer, with each chain comprising VL dAb, truncated CH1, hinge, CH2 and CH3 domains, CEP-37247 has a molecular mass of approximately 78kDa, which is about half the size of a conventional IgG molecule. Surface plasmon resonance data demonstrate that CEP-37247 possesses high selectivity and affinity for TNFα. CEP-37247 is a potent neutralizer of TNFα activity in vitro in the L929 TNF-mediated cytotoxicity assay. In a human TNFα-over-expressing mouse model of polyarthritis, CEP-37247 prevents development of disease, and is at least as effective as the marketed product etanercept. Fc functionality is intact - CEP-37247 is capable of mediating antibody-dependent cell-mediated cytotoxicity and has a circulating half-life of approximately 4.5 days in cynomolgus macaques. Given the favorable properties outlined above, and its high expression levels (approaching 7 g/L) in a CHOK1 based-expression system, CEP-37247 is progressing into the clinic, where other potential advantages such as enhanced efficacy due to improved tissue distribution, and beneficial immunogenicity profile, will be evaluated.

Evidence-based medicine audit as a tool for improving emergency ophthalmology.

AIM: To audit the proportion of interventions in emergency ophthalmology that are evidence based and to determine whether the quality of care can be improved. METHODS: Audit of diagnosis-intervention pairs was carried out retrospectively in March 2003. The outcomes were assessed for evidence level reached in the Medline database 1966-2003 and the Cochrane Database of Systematic Reviews. Locally agreed guidelines were issued and the study repeated prospectively in March 2004, when new medical staff were at a similar level of experience. The participants had no prior knowledge of the study to avoid prescribing bias (Hawthorne's phenomenon). RESULTS: In the first part of the audit in 2003, 71% of interventions were evidence based, with 36% derived from systematic reviews, meta-analysis or randomised controlled trials (evidence levels 1-3). After guidelines for care were implemented in 2004, there was an improvement in the number of evidence-based interventions to 82% (P=0.04), and levels 1-3 were reached in 60% (P=0.02). The proportion with no evidence or against evidence dropped from 29 to 18% (P=0.04). An additional benefit was to reduce the number of re-attendances required. CONCLUSION: Evidence-based medicine can be used to improve the quality of care in the acute ophthalmic setting, both in refining the standard of interventions and in reducing the number of hospital visits.

Analysis of the structure and function of the transcriptional coregulator HOP.

Homeodomain-only protein (HOP) is an 8-kDa transcriptional corepressor that is essential for the normal development of the mammalian heart. Previous studies have shown that HOP, which consists entirely of a putative homeodomain, acts downstream of Nkx2.5 and associates with the serum response factor (SRF), repressing transcription from SRF-responsive genes. HOP is also able to recruit histone deacetylase (HDAC) activity, consistent with its ability to repress transcription. Unlike other classic homeodomain proteins, HOP does not appear to interact with DNA, although it has been unclear if this is because of an overall divergent structure or because of specific amino acid differences between HOP and other homeodomains. To work toward an understanding of HOP function, we have determined the 3D structure of full-length HOP and used a range of biochemical assays to define the parts of the protein that are functionally important for its repression activity. We show that HOP forms a classical homeodomain fold but that it cannot recognize double stranded DNA, a result that emphasizes the importance of caution in predicting protein function from sequence homology alone. We also demonstrate that two distinct regions on the surface of HOP are required for its ability to repress an SRF-driven reporter gene, and it is likely that these motifs direct interactions between HOP and partner proteins such as SRF- and HDAC-containing complexes. Our results demonstrate that the homeodomain fold has been co-opted during evolution for functions other than sequence-specific DNA binding and suggest that HOP functions as an adaptor protein to mediate transcriptional repression.

Molecular analysis of the interaction between the hematopoietic master transcription factors GATA-1 and PU.1.

GATA-1 and PU.1 are transcription factors that control erythroid and myeloid development, respectively. The two proteins have been shown to function in an antagonistic fashion, with GATA-1 repressing PU.1 activity during erythropoiesis and PU.1 repressing GATA-1 function during myelopoiesis. It has also become clear that this functional antagonism involves direct interactions between the two proteins. However, the molecular basis for these interactions is not known, and a number of inconsistencies exist in the literature. We have used a range of biophysical methods to define the molecular details of the GATA-1-PU.1 interaction. A combination of NMR titration data and extensive mutagenesis revealed that the PU.1-Ets domain and the GATA-1 C-terminal zinc finger (CF) form a low affinity interaction in which specific regions of each protein are implicated. Surprisingly, the interaction cannot be disrupted by single alanine substitution mutations, suggesting that binding is distributed over an extended interface. The C-terminal basic tail region of CF appears to be sufficient to mediate an interaction with PU.1-Ets, and neither acetylation nor phosphorylation of a peptide corresponding to this region disrupts binding, indicating that the interaction is not dominated by electrostatic interactions. The CF basic tail shares significant sequence homology with the PU.1 interacting motif from c-Jun, suggesting that GATA-1 and c-Jun might compete to bind PU.1. Taken together, our data provide a molecular perspective on the GATA-1-PU.1 interaction, resolving several issues in the existing data and providing insight into the mechanisms through which these two proteins combine to regulate blood development.

Zinc fingers as protein recognition motifs: structural basis for the GATA-1/friend of GATA interaction.

GATA-1 and friend of GATA (FOG) are zinc-finger transcription factors that physically interact to play essential roles in erythroid and megakaryocytic development. Several naturally occurring mutations in the GATA-1 gene that alter the FOG-binding domain have been reported. The mutations are associated with familial anemias and thrombocytopenias of differing severity. To elucidate the molecular basis for the GATA-1/FOG interaction, we have determined the three-dimensional structure of a complex comprising the interaction domains of these proteins. The structure reveals how zinc fingers can act as protein recognition motifs. Details of the architecture of the contact domains and their physical properties provide a molecular explanation for how the GATA-1 mutations contribute to distinct but related genetic diseases.

Purification of Streptococcus group C bacteriophage lysin.

A simple procedure for the purification of Streptococcus group C phage lysin to apparent homogeneity is described. The electrophoretically pure, enzymatically stable polypeptide of 98,000 molecular weight converted Streptococcus (groups A, F, and H) cells into spheroplasts within 5 min at 0 degrees C or within less than a minute at 37 degrees C.

Local anesthetics block transient expression of inducible functions for transformation in Streptococcus sanguis.

Procaine and tetracaine reversibly inhibit transformation by preventing the transient expression of competence-specific, inducible functions, which are usually triggered in response to cellular stimulation with competence protein. Affinity studies with 14C-labeled procaine showed that the anesthetic bound to cell surface macromolecules specifically in the initiation phases of competence-specific events and blocked transfer of information imparted by cellular membrane receptor(s) upon interaction with competence protein.

Comitant strabismus.

This review reports on articles written on comitant strabismus during the past year. Congenital esotropia was a recurring theme in these publications. Included in this review are articles that provide an insight into the basis for motor epiphenomena such as optokinetic nystagmus asymmetry and latent nystagmus. The optimum window of opportunity to achieve quality binocular vision by surgical alignment in congenital esotropia is discussed. We also report on articles that address various aspects of the management of comitant strabismus including the amount of medial rectus recession for esotropia, the target angle for best results in accommodative esotropia with high accommodation convergence/accommodation ratio, and issues related to comitant exotropia.

Switches in macromolecular synthesis during induction of competence for transformation of Streptococcus sanguis.

The induction of synchronous development of competence for genetic transformation in Streptococcus sanguis, by either endogenous or exogenous competence factor (CF), is manifested in the transient synthesis of a new set of at least 10 polypeptides, ranging from 14,000 to 51,000 in molecular weight. Eight polypeptides (E14, E16, E24, E28, E32, E37, E44, E51) appear early, and two polypeptides (L34, L42) appear 5-10 min later. One of the newly synthesized early polypeptides, E16, is shown to be a component of the presynaptic complex containing single-stranded DNA that is produced in vivo upon uptake of native donor DNA. Concomitant with this induced synthesis of competence-specific polypeptides there is a net decrease in RNA and protein synthesis but no change in DNA synthesis; donor DNA-binding ability and transformability reach maxima during the phase of diminishing macromolecular synthesis. Subsequently, donor DNA-binding ability and transformability decay at disproportionate rates as cells return to the normal state of macromolecular synthesis within one generation. Coincident with the induction of competence, the synthesis of a new RNA transcript of high molecular weight appears to be induced which continues during the restricted phase of total cellular RNA synthesis.

Deoxyribonucleate binding and transformation in Rhizobium jpaonicum.

Rhizobium japonicum, capable of binding high-molecular-weight donor (32)P-labeled deoxyribonucleic acid (DNA) during late log phase in a competence medium, was transformed for streptomycin resistance with a frequency of transformation ranging between 0.02 and 0.08%. Eight to 10% of the homologous native (32)P-labeled input DNA was bound irreversibly in a temperature-dependent manner. Homologous denatured (32)P-labeled DNA was incapable of binding to the recipient under similar conditions. CsCl density gradient banding of the donor and recipient DNA indicated homology. The low frequency of transformation could be due to one or more steps that occur between DNA uptake and integration.