Genetic confirmation of a hybrid between two highly divergent cardinalid species: A rose‐breasted grosbeak (Pheucticus ludovicianus) and a scarlet tanager (Piranga olivacea)

Using low‐coverage whole‐genome sequencing, analysis of vocalizations, and inferences from natural history, we document a first‐generation hybrid between a rose‐breasted grosbeak (Pheucticus ludovicianus) and a scarlet tanager (Piranga olivacea). These two species occur sympatrically throughout much of eastern North America, although were not previously known to interbreed. Following the field identification of a putative hybrid, we use genetic and bioacoustic data to show that a rose‐breasted grosbeak was the maternal parent and a scarlet tanager was the paternal parent of the hybrid, whose song was similar to the latter species. These two species diverged >10 million years ago, and thus it is surprising to find a hybrid formed under natural conditions in the wild. Notably, the hybrid has an exceptionally heterozygous genome, with a conservative estimate of a heterozygous base every 100 bp. The observation that this hybrid of such highly divergent parental taxa has survived until adulthood serves as another example of the capacity for hybrid birds to survive with an exceptionally divergent genomic composition.     

Slow and Fast Muscle Fibers Are Preferentially Derived from Myoblasts Migrating into the Chick Limb Bud at Different Developmental Times

Avian limb myoblasts originate from somites and migrate into the periphery during limb bud formation. It is not known how these precursors become arranged into a stereotyped pattern of muscles and primary fiber types. We used in vivo surgical transplantation and anatomical analyses of thigh muscle patterns to ask whether myoblasts migrating into the limb bud at different developmental times adopt different fates. When myoblast migration was interrupted by transplanting limb bud tissue to the coelomic cavity of a host embryo early in the migratory period (stages 16-early 17), few thigh muscles were found at stages 30-33. Primordia that were present corresponded to muscles that normally contain a majority of slow myotubes. In limbs transplanted slightly later (stages late 17-18), the only missing muscles were those that normally contain the highest numbers of fast myotubes. Parallel results were obtained in chimeric limbs made by transplanting a quail limb bud to a chick host at different times during the migratory period, an experimental situation in which the limbs were not depleted of muscle precursors or nerves. These findings suggest that the earliest myoblast migrants give rise mainly to slow primary myotubes, the later migrants to fast myotubes. To determine whether the early limb bud environment defines the fate of migrating myoblasts, we assessed fiber type patterns in limbs that developed from young limb bud tissue (stages 15-early 16) transplanted to older hosts (stage 17). A significant depletion of slow myosin-positive profiles was found within slow muscles. Fast muscles were generally normal in size. These results provide in vivo evidence that limb myoblast diversity arises prior to the entry of myoblasts into the limb. We suggest that there is a gradual change in the proportions of myoblasts capable of forming slow and fast fiber types, a change which may begin in the somites or early in the migratory period.     

Nonspecificity in a nonimmune human scFv repertoire

Efforts to develop effective antibody therapeutics are frequently hampered by issues such as aggregation and nonspecificity, often only detected in late stages of the development process. In this study, we used a high throughput cross-reactivity assay to select nonspecific clones from a naïve human repertoire scFv library displayed on the surface of yeast. Most antibody families were de-enriched; however, the rarely expressed VH6 family was highly enriched among nonspecific clones, representing almost 90% of isolated clones. Mutational analysis of this family reveals a dominant role of CDRH2 in driving nonspecific binding. Homology modeling of a panel of VH6 antibodies shows a constrained β-sheet structure in CDRH2 that is not present in other families, potentially contributing to nonspecificity of the family. These findings confirm the common decision to exclude VH6 from synthetic antibody libraries, and support VH6 polyreactivity as a possible important role for the family in early ontogeny and cause for its overabundance in cases of some forms of autoimmunity.     

Safety of Onartuzumab in Patients with Solid Tumors: Experience to Date from the Onartuzumab Clinical Trial Program

Background

Onartuzumab, a recombinant humanized monovalent monoclonal antibody directed against MET, the receptor for the hepatocyte growth factor, has been investigated for the treatment of solid tumors. This publication describes the safety profile of onartuzumab in patients with solid tumors using data from the global onartuzumab clinical development program.

Methods

Adverse event (AE) and laboratory data from onartuzumab phase II/III studies were analyzed and coded into standardized terms according to industry standards. The severity of AEs was assessed using the NCI Common Toxicity Criteria, Version 4. Medical Dictionary for Regulatory Activities (MedDRA) AEs were grouped using the standardized MedDRA queries (SMQs) “gastrointestinal (GI) perforation”, “embolic and thrombotic events, venous (VTE)”, and “embolic and thrombotic events, arterial (ATE)”, and the Adverse Event Group Term (AEGT) “edema.” The safety evaluable populations (patients who received at least one dose of study treatment) for each study were included in this analysis.

Results

A total of 773 onartuzumab-treated patients from seven studies (phase II, n = 6; phase III, n = 1) were included. Edema and VTEs were reported in onartuzumab-treated patients in all seven studies. Edema events in onartuzumab arms were generally grade 1–2 in severity, observed more frequently than in control arms and at incidences ranging from 25.4−65.7% for all grades and from 1.2−14.1% for grade 3. Hypoalbuminemia was also more frequent in onartuzumab arms and observed at frequencies between 77.8% and 98.3%. The highest frequencies of all grade and grade ≥3 VTE events were 30.3% and 17.2%, respectively in onartuzumab arms. The cumulative incidence of all grade ATE events ranged from 0−5.6% (grade ≥3, 0−5.1%) in onartuzumab arms. The frequency of GI perforation was below 10% in all studies; the highest estimates were observed in studies with onartuzumab plus bevacizumab for all grades (0−6.2%) and grade ≥3 (0−6.2%).

Conclusions

The frequencies of VTE, ATE, GI perforation, hypoalbuminemia, and edema in clinical studies were higher in patients receiving onartuzumab than in control arms; these are considered to be expected events in patients receiving onartuzumab.     

The effects of temperature change on lung liquid production by in vitro lungs from fetal guinea pigs

Lungs from fetal guinea pigs of 58-65 days of gestation were supported in vitro for 3 h, and lung liquid production rates were measured by a dye dilution technique. In 36 control preparations, incubated continuously at 37 degrees C, the average production rate in the first hour was 1.46 +/- 0.23 ml/h per kg body weight; there was no significant change over the following two h. In 36 further preparations the temperature was changed during the middle hour (ABA), with the following % reductions in production rates: at -1 degrees C (relative to 37 degrees C), 68.2 +/- 17.1%; -2 degrees C, 125.5 +/- 30.1% (reabsorption); -3 degrees C, 103.8 +/- 32.8% (reabsorption); -5 degrees C, 82.7 +/- 16.6%, -8 degrees C, 94.7 +/- 1.8 %; +2 degrees C, 100.7 +/- 12.6% (all significant, P less than 0.025-0.005). Slow recoveries followed a return to starting conditions, except after the increase in temperature, 10(-6) M amiloride abolished reabsorption, but not depression, during the maximal effects of temperature reduction (at -2 degrees C, n = 6); amiloride had no effect on control preparations (n = 6). These results suggest that: (a) reductions of 2-3 degrees C, as seen in the delivery room, abolish secretion, but not reabsorption of lung fluid; larger reductions stop both processes; (b) the reabsorptions seen after a fall in temperature depend on Na(+)-transport mechanisms; (c) lung liquid production was sensitive to a rise in temperature, so that fevers might adversely affect lung development, and (d) the fall in temperature at birth may be an important factor in the early reabsorption of lung liquid.     

Chronic Disease and Disability in the Community: A Prevalence Study

A two-stage prevalence survey of disability (defined as the inability to perform unaided defined activities essential to daily life) used questionnaires on a random sample of the population living in north Lambeth. The central estimates of the prevalence of disability in those aged 35-74 are 7·2% for men and 9·7% for women. Among the disabled population locomotor impairments were more common in women; internal impairments were more common in men. For men and women together chronic respiratory disease, mainly bronchitis, was shown to be the single most common condition associated with disability.Though for women there may be an association between low social class and disability and between marital break-up and disability, these associations, though statistically significant, are weak. The data are therefore considered to be more widely relevant for the planning of health and welfare services.     

Targeting prostate cancer cells with a multivalent PSMA inhibitor-guided streptavidin conjugate

Prostate-specific membrane antigen (PSMA), a type II membrane glycoprotein, its high expression is associated with prostate cancer progression, and has been becoming an active target for imaging or therapeutic applications for prostate cancer. On the other hand, streptavidin-biotin system has been successfully employed in pretargeting therapy towards multiple cancers. Herein, we describe the synthesis of bifunctional ligands (biotin-CTT54, biotin-PEG(4)-CTT54, and biotin-PEG(12)-CTT54) possessing two functional motifs separated by a length-varied polyethylene glycol (PEG) spacer: one (CTT54) binds tumor-marker PSMA and the other (biotin) binds streptavidin or avidin. All three compounds exhibited high potencies (IC(50) values: 1.21, 2.53, and 10nM, respectively) and irreversibility; but only biotin-PEG(12)-CTT54 demonstrated specifically labeling PSMA-positive prostate cancer cells in a two-step pretargeting procedure. Additionally, the pre-formulated complex between biotin-PEG(12)-CTT54 and Cy5-streptavidin displayed the improved inhibitory potency (IC(50)=1.86 nM) and irreversibility against PSMA and rapid uptake of streptavidin conjugate into PSMA-positive prostate cancer cells through PSMA-associated internalization. Together, all these results supported a proof-concept that combination of streptavidin and PSMA's biotinylated inhibitor may lead to development of a novel strategy of tumor-targeting imaging or drug delivery towards prostate cancer.