Separation of Protactinium Employing Sulfur-Based Extraction Chromatographic Resins.

Protactinium-230 ( t1/2 = 17.4 d) is the parent isotope of 230U ( t1/2 = 20.8 d), a radionuclide of interest for targeted alpha therapy (TAT). Column chromatographic methods have been developed to separate no-carrier-added 230Pa from proton irradiated thorium targets and accompanying fission products. Results reported within demonstrate the use of novel sulfur bearing chromatographic extraction resins for the selective separation of protactinium. The recovery yield of 230Pa was 93 ± 4% employing a R3P═S type commercially available resin and 88 ± 4% employing a DGTA (diglycothioamide) containing custom synthesized extraction chromatographic resin. The radiochemical purity of the recovered 230Pa was measured via high purity germanium γ-ray spectroscopy to be >99.5% with the remaining radioactive contaminant being 95Nb due to its similar chemistry to protactinium. Measured equilibrium distribution coefficients for protactinium, thorium, uranium, niobium, radium, and actinium on both the R3P═S type and the DGTA resin in hydrochloric acid media are reported, to the best of our knowledge, for the first time.

Innate Predator Odor Aversion Driven by Parallel Olfactory Subsystems that Converge in the Ventromedial Hypothalamus.

The existence of innate predator aversion evoked by predator-derived chemostimuli called kairomones offers a strong selective advantage for potential prey animals. However, it is unclear how chemically diverse kairomones can elicit similar avoidance behaviors. Using a combination of behavioral analyses and single-cell Ca(2+) imaging in wild-type and gene-targeted mice, we show that innate predator-evoked avoidance is driven by parallel, non-redundant processing of volatile and nonvolatile kairomones through the activation of multiple olfactory subsystems including the Grueneberg ganglion, the vomeronasal organ, and chemosensory neurons within the main olfactory epithelium. Perturbation of chemosensory responses in specific subsystems through disruption of genes encoding key sensory transduction proteins (Cnga3, Gnao1) or by surgical axotomy abolished avoidance behaviors and/or cellular Ca(2+) responses to different predator odors. Stimulation of these different subsystems resulted in the activation of widely distributed target regions in the olfactory bulb, as assessed by c-Fos expression. However, in each case, this c-Fos increase was observed within the same subnuclei of the medial amygdala and ventromedial hypothalamus, regions implicated in fear, anxiety, and defensive behaviors. Thus, the mammalian olfactory system has evolved multiple, parallel mechanisms for kairomone detection that converge in the brain to facilitate a common behavioral response. Our findings provide significant insights into the genetic substrates and circuit logic of predator-driven innate aversion and may serve as a valuable model for studying instinctive fear and human emotional and panic disorders.

Gastroparesis: A Review of Current Diagnosis and Treatment Options.

Gastroparesis (GP) is a chronic neuromuscular disorder of the upper gastrointestinal tract. The incidence of GP is not well described; however, the number of individuals affected by symptoms of GP in the United States is estimated to be over 4 million. The etiology of GP is diverse. Approximately 25% of cases are associated with diabetes, whereas nearly 50% are classified as idiopathic; many of these latter cases likely represent a postinfectious process. Connective tissue disorders, autoimmune disorders, prior gastric surgery, ischemia, and medications make up the vast majority of the remaining cases. The pathophysiology of GP is also diverse. Abnormalities in fundic tone, antroduodenal dyscoordination, a weak antral pump, gastric dysrhythmias, and abnormal duodenal feedback all contribute to delays in gastric emptying and symptom expression. Characteristic symptoms of GP include nausea, vomiting, epigastric pain, early satiety, and weight loss. The diagnosis of GP is made using a combination of characteristic symptoms in conjunction with objective evidence of delayed gastric emptying in the absence of mechanical obstruction. Once the diagnosis is made, treatment options include dietary modification, medications to accelerate gastric emptying, antiemetic agents, gastric electrical stimulation, and surgery. In the following sections we will provide an overview of the health care impact of GP, describe the underlying pathophysiology, and review treatment options using an evidence-based approach.