Stem Cells to Insulin Secreting Cells: Two Steps Forward and Now a Time to Pause?

Two groups recently reported the in vitro differentiation of human embryonic stem cells into insulin-secreting cells, achieving an elusive goal for regenerative medicine. Herein we provide a perspective regarding these developments, compare phenotypes of the insulin-containing cells to human β cells, and discuss implications for type 1 diabetes research and clinical care

DEVELOPMENT OF RECOMBINANT PROTEIN BASED CHEMICAL CONJUGATE MALARIA VACCINES TARGETING THE PRE-ERYTHROCYTIC STAGE, TRANSMISSION BLOCKING, OR BOTH

The development of a Plasmodium falciparum malaria vaccine is critical for future control and elimination programs. Recombinant protein based chemical conjugate vaccines, covering different parasite stages, are being developed due to complexity of the parasite and sub-optimal immunogenicity of recombinant malaria proteins in humans, respectively. Chemical conjugation of recombinant malaria proteins to carrier proteins improves their immunogenicity in animal studies. A transmission blocking vaccine comprised of the ookinete protein Pfs25 chemically conjugated to Pseudomonas aeruginosa ExoProtein A (EPA) is currently being developed for pilot scale cGMP production. Bulk lots of Pfs25 and EPA have already been produced and released following cGMP. Appropriate analytical assays are being evaluated for both in-process and bulk release of the Pfs25-EPA conjugate vaccine. One critical assay already evaluated for determining the average mass is analytical size exclusion HPLC coupled with multi-angle light scattering. Phase 1 human clinical trials are planned for 2011. Another biological target of interest is the circumsporozoite protein (CSP), the most abundant and immunogenic protein on the surface of the sporozoite. A recombinant nearly full-length CSP has been produced in the methylotrophic yeast Pichia pastoris containing a bioengineered free thiol for chemical conjugation to various carrier proteins, including a chemically conjugated form of Pfs25. This recombinant protein based chemical conjugation platform, in combination with better adjuvant selection, will improve the potential for developing an efficacious malaria vaccine

STEAP4 expression in human islets is associated with differences in body mass index, sex, HbA1c, and inflammation

Objective STEAP4 (six-transmembrane epithelial antigen of the prostate 4) is a metalloreductase that has been shown previously to protect cells from inflammatory damage. Genetic variants in STEAP4 have been associated with numerous metabolic disorders related to obesity, including putative defects in the acute insulin response to glucose in type 2 diabetes. Purpose We examined whether obesity and/or type 2 diabetes altered STEAP4 expression in human pancreatic islets. Methods Human islets were isolated from deceased donors at two medical centers and processed for quantitative polymerase chain reaction. Organ donors were selected by status as non-diabetic or having type 2 diabetes. Site 1 (Edmonton): N = 13 type 2 diabetes donors (7M, 6F), N = 20 non-diabetic donors (7M, 13F). Site 2 (Virginia): N = 6 type 2 diabetes donors (6F), N = 6 non-diabetic donors (3M, 3F). Results STEAP4 showed reduced islet expression with increasing body mass index among all donors (P < 0.10) and non-diabetic donors (P < 0.05) from Site 1; STEAP4 showed reduced islet expression among type 2 diabetes donors with increasing hemoglobin A1c. Islet STEAP4 expression was also marginally higher in female donors (P < 0.10). Among type 2 diabetes donors from Site 2, islet insulin expression was reduced, STEAP4 expression was increased, and white blood cell counts were increased compared to non-diabetic donors. Islets from non-diabetic donors that were exposed overnight to 5 ng/ml IL-1β displayed increased STEAP4 expression, consistent with STEAP4 upregulation by inflammatory signaling. Conclusions These findings suggest that increased STEAP4 mRNA expression is associated with inflammatory stimuli, whereas lower STEAP4 expression is associated with obesity in human islets. Given its putative protective role, downregulation of STEAP4 by chronic obesity suggests a mechanism for reduced islet protection against cellular damage

Effects of the COVID-19 lockdown on orthopaedic trauma:a multicentre study across Scotland

Aims: The UK government declared a national lockdown on 23 March 2020 to reduce transmission of COVID-19. This study aims to identify the effect of lockdown on the rates, types, mechanisms, and mortality of musculoskeletal trauma across Scotland.Methods: Data for all musculoskeletal trauma requiring operative treatment were collected prospectively from five key orthopaedic units across Scotland during lockdown (23 March 2020 to 28 May 2020). This was compared with data for the same timeframe in 2019 and 2018. Data collected included all cases requiring surgery, injury type, mechanism of injury, and inpatient mortality.Results: A total of 1,315 patients received operative treatment from 23 March 2020 to 28 May 2020 compared with 1,791 in 2019 and 1,719 in 2018. The numbers of all injury types decreased, but the relative frequency of hip fractures increased (36.3% in 2020 vs 30.2% in 2019, p &lt; 0.0001 and 30.7% in 2018, p &lt; 0.0001). Significant increases were seen in the proportion of DIY-related injuries (3.1% in 2020 vs 1.7% in 2019, p = 0.012 and 1.6% in 2018, p &lt; 0.005) and injuries caused by falls (65.6% in 2020 vs 62.6% in 2019, p = 0.082 and 61.9% in 2018, p = 0.047). Significant decreases were seen in the proportion of road traffic collisions (2.6% in 2020 vs 5.4% in 2019, p &lt; 0.0001 and 4.2% in 2018, p = 0.016), occupational injuries (1.8% in 2020 vs 3.0% in 2019, p = 0.025 and 2.3% in 2018, p = 0.012) and infections (6.8% in 2020 vs 7.8% in 2019, p = 0.268 and 10.3% in 2018, p &lt; 0.012). Cycling injuries increased (78 in 2020 vs 64 in 2019 vs 42 in 2018). A significant increase in the proportion of self-harm injuries was seen (1.7% in 2020 vs 1.1% in 2019, p = 0.185 and 0.5% in 2018, p &lt; 0.0001). Mortality of trauma patients was significantly higher in 2020 (5.0%) than in 2019 (2.8%, p = 0.002) and 2018 (1.8%, p &lt; 0.0001).Conclusion: The UK COVID-19 lockdown has resulted in a marked reduction in musculoskeletal trauma patients undergoing surgery in Scotland. There have been significant changes in types and mechanisms of injury and, concerningly, mortality of trauma patients has risen significantly.</p

Corelease and Differential Exit via the Fusion Pore of GABA, Serotonin, and ATP from LDCV in Rat Pancreatic β Cells

The release of γ-aminobutyric acid (GABA) and ATP from rat β cells was monitored using an electrophysiological assay based on overexpression GABA(A) or P(2)X(2) receptor ion channels. Exocytosis of LDCVs, detected by carbon fiber amperometry of serotonin, correlated strongly (∼80%) with ATP release. The increase in membrane capacitance per ATP release event was 3.4 fF, close to the expected capacitance of an individual LDCV with a diameter of 0.3 μm. ATP and GABA were coreleased with serotonin with the same probability. Immunogold electron microscopy revealed that ∼15% of the LDCVs contain GABA. Prespike “pedestals,” reflecting exit of granule constituents via the fusion pore, were less frequently observed for ATP than for serotonin or GABA and the relative amplitude (amplitude of foot compared to spike) was smaller: in some cases the ATP-dependent pedestal was missing entirely. An inward tonic current, not dependent on glucose and inhibited by the GABA(A) receptor antagonist SR95531, was observed in β cells in clusters of islet cells. Noise analysis indicated that it was due to the activity of individual channels with a conductance of 30 pS, the same as expected for individual GABA(A) Cl(−) channels with the ionic gradients used. We conclude that (a) LDCVs accumulate ATP and serotonin; (b) regulated release of GABA can be accounted for by exocytosis of a subset of insulin-containing LDCVs; (c) the fusion pore of LDCVs exhibits selectivity and compounds are differentially released depending on their chemical properties (including size); and (d) a glucose-independent nonvesicular form of GABA release exists in β cells

A photographic and acoustic transect across two deep-water seafloor mounds, Mississippi Canyon, northern Gulf of Mexico

This paper is not subject to U.S. copyright. The definitive version was published in Marine and Petroleum Geology 25 (2008): 969-976, doi:10.1016/j.marpetgeo.2008.01.020.In the northern Gulf of Mexico, a series of seafloor mounds lie along the floor of the Mississippi Canyon in Atwater Valley lease blocks 13 and 14. The mounds, one of which was drilled by the Chevron Joint Industry Project on Methane Hydrates in 2005, are interpreted to be vent-related features that may contain significant accumulations of gas hydrate adjacent to gas and fluid migration pathways. The mounds are located not, vert, similar150 km south of Louisiana at not, vert, similar1300 m water depth. New side-scan sonar data, multibeam bathymetry, and near-bottom photography along a 4 km northwest–southeast transect crossing two of the mounds (labeled D and F) reveal the mounds' detailed morphology and surficial characteristics. Mound D, not, vert, similar250 m in diameter and 7–10 m in height, has exposures of authigenic carbonates and appears to result from a seafloor vent of slow-to-moderate flux. Mound F, which is not, vert, similar400 m in diameter and 10–15 m high, is covered on its southwest flank by extruded mud flows, a characteristic associated with moderate-to-rapid flux. Chemosynthetic communities visible on the bottom photographs are restricted to bacterial mats on both mounds and mussels at Mound D. No indications of surficial gas hydrates are evident on the bottom photographPartial support for the research cruises that collected the data for this study was provided by the Department of Energy, National Energy Technology Lab

Selective nanomanipulation using optical forces

We present a detailed theoretical study of the recent proposal for selective nanomanipulation of nanometric particles above a substrate using near-field optical forces [Chaumet {\it et al.} Phys. Rev. Lett. {\bf 88}, 123601 (2002)]. Evanescent light scattering at the apex of an apertureless near-field probe is used to create an optical trap. The position of the trap is controlled on a nanometric scale via the probe and small objects can be selectively trapped and manipulated. We discuss the influence of the geometry of the particles and the probe on the efficiency of the trap. We also consider the influence of multiple scattering among the particles on the substrate and its effect on the robustness of the trap.Comment: 12 pages, 17 figure