Identification of a Candidate CD5 Homologue in the Amphibian Xenopus laevis

We identified a novel T cell Ag in the South African clawed toad (Xenopus laevis) by a mAb designated 2B1. This Ag is present in relatively high levels on most thymocytes, approximately 65% of splenocytes, 55% of PBL, and 65% of intestinal lymphocytes, but is rarely seen on IgM+ B cells in any of these tissues. Lymphocytes bearing the 2B1 Ag proliferate in response to stimulation with Con A or PHA, whereas the 2B1- lymphocytes are reactive to LPS. Biochemical analysis indicates that this Ag is a differentially phosphorylated glycoprotein of 71 to 82 kDa. The protein core of 64 kDa bears both N- and O-linked carbohydrate side chains. The amino-terminal protein sequence of the 2B1 Ag shares significant homology with both the macrophage scavenger receptor type 1 motif and the mammalian CD5/CD6 family. The biochemical characteristics and cellular distribution of the 2B1 Ag suggest that it represents the CD5 homologue in X. laevis. While T cells constitutively express this highly conserved molecule, Xenopus B cells acquire the CD5 homologue only when they are stimulated in the presence of T cell

Identification of T-cell receptor a-chain genes in the chicken

T-cell receptor (TCR) -chain (TCR) and ß-chain (TCRß) genes are well characterized in mammals, while only TCRß genes have been identified in other vertebrates. To identify avian TCR genes, we used monoclonal anti-CD3 antibodies to isolate chicken TCR for peptide sequence analysis. Degenerate oligonucleotide probes were then used to isolate a candidate TCR cDNA clone that hybridized with a 1.7-kb mRNA species present only in ß T cells and in tissues populated by these cells. Southern blot analysis revealed gene rearrangement in thymocytes and ß T-cell lines. The TCR cDNA candidate encoded an openreading frame of 275 amino acids, the predicted variable (V)-, joining (J)-, and constant (C)-region amino acid sequences of which shared 40%, 60%, and 25% homology with corresponding mammalian sequences. A single C gene and 25 V genes were identified by using region-specific probes. The V cDNA probe isolated from a Vß1+ cell line reacted with transcripts from one of five Vß2+ cell lines, suggesting shared use of V genes by Vß1+ and Vß2+ T cells and the existence of other V gene families. A genomic V sequence was flanked by classical recombination signal sequences but, unlike previously defined V genes, the leader and V region were encoded by a single exon. The data indicate evolutionary conservation of the basic TCR gene structure in birds and mammal

Apparent wave function collapse caused by scattering

Some experimental implications of the recent progress on wave function collapse are calculated. Exact results are derived for the center-of-mass wave function collapse caused by random scatterings and applied to a range of specific examples. The results show that recently proposed experiments to measure the GRW effect are likely to fail, since the effect of naturally occurring scatterings is of the same form as the GRW effect but generally much stronger. The same goes for attempts to measure the collapse caused by quantum gravity as suggested by Hawking and others. The results also indicate that macroscopic systems tend to be found in states with (Delta-x)(Delta-p) = hbar/sqrt(2), but microscopic systems in highly tiltedly squeezed states with (Delta-x)(Delta-p) >> hbar.Comment: Final published version. 20 pages, Plain TeX, no figures. Online at http://astro.berkeley.edu/~max/collapse.html (faster from the US), from http://www.mpa-garching.mpg.de/~max/collapse.html (faster from Europe) or from [email protected]

Does the universe in fact contain almost no information?

At first sight, an accurate description of the state of the universe appears to require a mind-bogglingly large and perhaps even infinite amount of information, even if we restrict our attention to a small subsystem such as a rabbit. In this paper, it is suggested that most of this information is merely apparent, as seen from our subjective viewpoints, and that the algorithmic information content of the universe as a whole is close to zero. It is argued that if the Schr\"odinger equation is universally valid, then decoherence together with the standard chaotic behavior of certain non-linear systems will make the universe appear extremely complex to any self-aware subsets that happen to inhabit it now, even if it was in a quite simple state shortly after the big bang. For instance, gravitational instability would amplify the microscopic primordial density fluctuations that are required by the Heisenberg uncertainty principle into quite macroscopic inhomogeneities, forcing the current wavefunction of the universe to contain such Byzantine superpositions as our planet being in many macroscopically different places at once. Since decoherence bars us from experiencing more than one macroscopic reality, we would see seemingly complex constellations of stars etc, even if the initial wavefunction of the universe was perfectly homogeneous and isotropic.Comment: 17 pages, LATeX, no figures. Online with refs at http://astro.berkeley.edu/~max/nihilo.html (faster from the US), from http://www.mpa-garching.mpg.de/~max/nihilo.html (faster from Europe) or from [email protected]

Dissociation of virtual photons in events with a leading proton at HERA

The ZEUS detector has been used to study dissociation of virtual photons in events with a leading proton, gamma^* p -> X p, in e^+p collisions at HERA. The data cover photon virtualities in two ranges, 0.03<Q^2<0.60 GeV^2 and 2<Q^2<100 GeV^2, with M_X>1.5 GeV, where M_X is the mass of the hadronic final state, X. Events were required to have a leading proton, detected in the ZEUS leading proton spectrometer, carrying at least 90% of the incoming proton energy. The cross section is presented as a function of t, the squared four-momentum transfer at the proton vertex, Phi, the azimuthal angle between the positron scattering plane and the proton scattering plane, and Q^2. The data are presented in terms of the diffractive structure function, F_2^D(3). A next-to-leading-order QCD fit to the higher-Q^2 data set and to previously published diffractive charm production data is presented

Adherence to a femoral neck fracture treatment guideline

Purpose: In 2007 the Dutch Surgical Society published a clinical practice guideline for the treatment of hip fracture patients, based on the best available international evidence at that time. We investigated to what extent treatment of femoral neck fracture patients in the Netherlands corresponded with these guidelines, and determined differences in patient characteristics between the treatment groups. Methods: All femoral neck fracture patients treated in 14 hospitals between February 2008 and August 2009 were included. Patient characteristics, X-rays, and treatment data were collected retrospectively. Results: From a total of 1,250 patients 59 % had been treated with arthroplasty, 39 % with internal fixation, and 2 % with a non-operative treatment. While 74 % of the treatment choices complied with the guideline, 12 % did not. In 14 % adherence could not be determined from the available data. Arthroplasty was preferred over internal fixation in elderly patients with severe comorbidity, pre-fracture osteoporosis and a displaced fracture, who were ambulatory with aids pre-fracture (odds ratio, OR 2.2-58.1). Sliding hip screws were preferred over cancellous screws in displaced fractures (OR 1.9). Conclusions: Overall guideline adherence was good. Most deviations concerned treatment of elderly patients with a displaced fracture and implant use in internal fixation. Additional data on these issues, preferably at a higher scientific level of evidence, is needed in order to improve the guideline and to reinforce a more uniform treatment of these patients

Using qualitative methods to explore lay explanatory models, health-seeking behaviours and self-care practices of podoconiosis patients in north-west Ethiopia

Background: Podoconiosis (endemic non-filarial elephantiasis) is a chronic, non-infectious disease resulting from exposure of bare feet to red-clay soil in tropical highlands. This study examined lay beliefs about three under-researched aspects of podoconiosis patients’ care: explanatory models, health-seeking behaviours and self-care. Methods: In-depth interviews and focus group discussions were undertaken with 34 participants (19 male, 15 female) between April-May 2015 at podoconiosis treatment centres across East and West Gojjam regions in north-west Ethiopia. Results: Explanatory models for podoconiosis included contamination from blood, magic, soil or affected individuals. Belief in heredity or divine punishment often delayed clinic attendance. All participants had tried holy water treatment and some, holy soil. Herbal treatments were considered ineffectual, costly and appeared to promote fluid escape. Motivators for clinic attendance were failure of traditional treatments and severe or disabling symptoms. Patients did not report self-treatment with antibiotics. Self-care was hindered by water being unavailable or expensive and patient fatigue. Conclusion: A pluralistic approach to podoconiosis self-treatment was discovered. Holy water is widely valued, though some patients prefer holy soil. Priests and traditional healers could help promote self-care and “signpost” patients to clinics. Change in behaviour and improving water access is key to self-care