Extremely metal-poor stars from the cosmic dawn in the bulge of the Milky Way

The first stars are predicted to have formed within 200 million years after the Big Bang, initiating the cosmic dawn. A true first star has not yet been discovered, although stars with tiny amounts of elements heavier than helium ('metals') have been found in the outer regions ('halo') of the Milky Way. The first stars and their immediate successors should, however, preferentially be found today in the central regions ('bulges') of galaxies, because they formed in the largest over-densities that grew gravitationally with time. The Milky Way bulge underwent a rapid chemical enrichment during the first 1-2 billion years, leading to a dearth of early, metal-poor stars. Here we report observations of extremely metal-poor stars in the Milky Way bulge, including one star with an iron abundance about 10,000 times lower than the solar value without noticeable carbon enhancement. We confirm that most of the metal-poor bulge stars are on tight orbits around the Galactic Centre, rather than being halo stars passing through the bulge, as expected for stars formed at redshifts greater than 15. Their chemical compositions are in general similar to typical halo stars of the same metallicity although intriguing differences exist, including lower abundances of carbon.

Neurogenic overactive bladder in spinal cord injury and multiple sclerosis: role of onabotulinumtoxinA

People with neurogenic overactive bladder from either multiple sclerosis or spinal cord injury often suffer significant morbidity and decreased quality of life. Here we review the pathophysiology of neurogenic overactive bladder and the impact it can have on people with multiple sclerosis or spinal cord injury. We also address the various traditional treatment options and focus on the use of botulinum toxin A (specifically onabotulinumtoxinA) for this condition.

Intrathecal drug therapy using the Codman Model 3000 Constant Flow Implantable Infusion Pumps: experience with 17 cases

OBJECTIVES

The objective of this study was to evaluate the accuracy, reliability, safety, and efficacy of the Codman Model 3000 Constant Flow Implantable Infusion Pump for intrathecal baclofen delivery as a therapeutic option for the treatment of severe spasticity. The distinctive features of this pump include a raised, easily palpable septum, a safety valve protecting the bolus pathway, no programmer needed, and no battery to fail.

DESIGN

A total of 17 patients with spinal cord injury, multiple sclerosis, or cerebral palsy were implanted with this pump. The accuracy of the pump and drug treatment efficacy was determined at each visit and adjustments to the dosages were made as required. All the intrathecal drug delivery system complications were reviewed.

RESULTS

The expected efficacy was achieved. The accuracy of the implanted pumps ranged from 90-97% (average 94%). There were no complications due to primary pump problems. The complications reported are similar to other implantable infusion devices and include dehiscence of the suture line, pressure ulcer development, formation of seroma, inversion of the pump, baclofen overdose, and catheter failures.

CONCLUSION

The Codman Model 3000 Constant Flow Implantable Infusion Pump is an accurate, reliable, and convenient option for patients needing intrathecal baclofen therapy, with complications similar to other available pumps.