Thermally Induced Oxidation of [FeII(tacn)2](OTf)2 (tacn = 1,4,7-triazacyclononane).

We previously reported the spin-crossover (SC) properties of [FeII(tacn)2](OTf)2 (1) (tacn = 1,4,7-triazacyclononane) [Eur. J. Inorg. Chem. 2013, 2115]. Upon heating under dynamic vacuum, 1 undergoes oxidation to generate a low spin iron(III) complex. The oxidation of the iron center was found to be facilitated by initial oxidation of the ligand via loss of an H atom. The resulting complex was hypothesized to have the formulation [FeIII(tacn)(tacn-H)](OTf)2 (2) where tacn-H is N-deprotonated tacn. The formulation was confirmed by ESI-MS. The powder EPR spectrum of the oxidized product at 77 K reveals the formation of a low-spin iron(III) species with rhombic spectrum (g = 1.98, 2.10, 2.19). We have indirectly detected H2 formation during the heating of 1 by reacting the headspace with HgO. Formation of water (1HNMR in anhydrous d6-DMSO) and elemental mercury were observed. To further support this claim, we independently synthesized [FeIII(tacn)2](OTf)3 (3) and treated it with one equiv base yielding 2. The structures of 3 was characterized by X-ray crystallography. Compound 2 also exhibits a low spin iron(III) rhombic signal (g = 1.97, 2.11, 2.23) in DMF at 77 K. Variable temperature magnetic susceptibility measurements indicate that 3 undergoes gradual spin increase from 2 to 400 K. DFT studies indicate that the deprotonated nitrogen in 2 forms a bond to iron(III) exhibiting double bond character (Fe-N, 1.807 Å).

Metabolism studies of a small-molecule tumor necrosis factor-alpha (TNF-α) inhibitor, UTL-5b (GBL-5b).

UTL-5b is an anti-inflammatory and anti-arthritic small-molecule tumor necrosis factor-alpha inhibitor and a structural analogue of the anti-arthritic drug, leflunomide. Leflunomide is known to be metabolized to teriflunomide, but the metabolites of UTL-5b have not been reported. The objective of this study was to investigate whether UTL-5b has a similar metabolic behavior as leflunomide. Preliminary studies showed that when exposed to microsomes in vitro with or without NADPH, UTL-5b disappeared within 30 min. To further investigate the microsomal metabolism, liquid chromatography-ultraviolet (LC-UV) and LC/tandem mass spectrometry (LC-MS/MS) were employed to, respectively, monitor the microsomal metabolites and identify the structure of the metabolites using LC-full scan MS and LC combined with multiple-ion monitoring MS. Fragmentation determination was analyzed by two types of scans: product ion scans and precursor ion scan. The in vitro microsomal treatment of UTL-5b resulted in two major metabolites: 5-methylisoxazole-3-carboxylic acid and 2-chloroaniline. Thus, the in vitro metabolic behavior of UTL-5b appears to be different from that of leflunomide in that the isoxazole ring is cleaved.

Mono-2-ethylhexyl phthalate (MEHP) alters histiotrophic nutrition pathways and epigenetic processes in the developing conceptus.

Histiotrophic nutrition pathways (HNPs) are processes by which the organogenesis-stage conceptus obtains nutrients, amino acids, vitamins and cofactors required for protein biosynthesis and metabolic activities. Nutrients are captured from the maternal milieu as whole proteins and cargoes via receptor-mediated endocytosis in the visceral yolk sac (VYS), degraded by lysosomal proteolysis and delivered to the developing embryo (EMB). Several nutrients obtained by HNPs are required substrates for one-carbon (C1) metabolism and supply methyl groups required for epigenetic processes, including DNA and histone methylation. Increased availability of methyl donors has been associated with reduced risk for neural tube defects (NTDs). Here, we show that mono-2-ethylhexyl phthalate (MEHP) treatment (100 or 250µM) alters HNPs, C1 metabolism and epigenetic programming in the organogenesis-stage conceptus. Specifically, 3-h MEHP treatment of mouse EMBs in whole culture resulted in dose-dependent reduction of HNP activity in the conceptus. To observe nutrient consequences of decreased HNP function, C1 components and substrates and epigenetic outcomes were quantified at 24h. Treatment with 100-µM MEHP resulted in decreased dietary methyl donor concentrations, while treatment with 100- or 250-µM MEHP resulted in dose-dependent elevated C1 products and substrates. In MEHP-treated EMBs with NTDs, H3K4 methylation was significantly increased, while no effects were seen in treated VYS. DNA methylation was reduced in MEHP-treated EMB with and without NTDs. This research suggests that environmental toxicants such as MEHP decrease embryonic nutrition in a time-dependent manner and that epigenetic consequences of HNP disruption may be exacerbated in EMB with NTDs.

Urology practice patterns after residency training in laparoscopy.

PURPOSE: Laparoscopic training has been incorporated into many urology residency programs. Although the impact of laparoscopic training courses has been examined, the impact of residency training in laparoscopy on subsequent urology practice patterns has not been assessed. MATERIALS AND METHODS: Urologists completing their residency from 1977 through 1999 at Tulane University and the University of California-San Diego were sent anonymous questionnaires in September 2000. The questionnaires evaluated practice demographics, operative experience in laparoscopy during residency, and the role of laparoscopy in the urologist's current practice. Factors impacting the decision to perform or not perform laparoscopy were evaluated. RESULTS: Sixty-one former residents (67%) responded to the questionnaire. Urologists were more likely to perform laparoscopic procedures if they had been trained during their residency (69%) than if they had no experience during residency (34%; p < 0.025). Intensity of laparoscopic experience in residency did not appear to correlate with ongoing practice, with 73% of residents having <15 cases during residency training continuing to perform laparoscopy compared with 67% of residents doing 15 to 80 laparoscopic cases. Urologists who had been trained in laparoscopy during residency cited the need for more training (47%) and inadequate case volume (47%) as reasons for not currently performing laparoscopy. Among those who had received residency training, the most common reasons given were inadequate case volume (61%) and increased operative time (57%). CONCLUSIONS: This survey suggests that laparoscopic procedures are more likely to be performed by physicians who have received training during residency. As the number of urologists who have been trained in laparoscopy during residency increases, shifts in practice patterns will continue to evolve, along with advances in urologic laparoscopy.

Capillary fractionation of HPLC substrates by a microfluidic droplet generator for high throughput analysis.

Biochemical samples are complex mixtures containing 1000's of components which often must be fractionated prior to analysis. Conventional fraction collectors, which can only accommodate 10's of fractions, are not well suited for high throughput analysis. This paper describes microfractionation in droplets (µFD), a scalable microfluidic technique for generating thousands of fractions. A drop generator, placed downstream from a high performance liquid chromatography (HPLC) column, encapsulates the separated components into a serial array of monodisperse droplets. The droplets can be stored in a capillary or immediately used in subsequent assays. Using µFD, a mixture of 3 dyes separated in a C18 column was fractionated into 2,160 droplets in <6 min. The volume and frequency of the droplet fractions are governed by the capillary number (Ca), which depends on the viscosity of the carrier fluid, flow rate, and interfacial tension. With HPLC-compatible flow rates of 0.38-0.7 mL/min, in a 1.5 mm Teflon capillary, fractions contain volumes of 1-6 µL and are generated at 2-10 drops/s. Droplet fractions can be mixed with a subsequent reagent using a downstream tee junction. In theory, µFD can be coupled to a wide variety of separation processes, enabling high throughput fractionation and screening of complex mixtures in µL to sub-nL volumes.

Urology practice patterns after residency training in radical perineal prostatectomy.

OBJECTIVES: To assess the impact of residency training in radical perineal prostatectomy (RPP) on subsequent use of RPP in urology practice. METHODS: Urologists who completed residency training at Tulane University and the University of California, San Diego, Medical Center from 1977 to 1999 were surveyed by anonymous questionnaire for their practice demographics, operative experience in RPP during residency, the role of RPP in their current practice, and the reasons they do or do not perform RPP. RESULTS: Of 91 former residents, 61 (67%) responded. RPP was in current use by 41% of the urologists trained in RPP during residency and by 13% of those with no residency RPP training. Those who had performed 10 or more RPPs during residency reported a higher rate of current RPP use (53%) than did those who had performed fewer than 10 RPPs during residency (21%). Urologists trained in RPP during residency cited partner preference (28%) and inadequate exposure (26%) as reasons they did not perform RPP; respondents with no residency RPP training cited inadequate exposure (25%), difficulty of the operation (25%), and time required to perform the operation (25%). CONCLUSIONS: A urologist with residency training in RPP is more likely to perform RPP in practice than is a urologist without such training. The intensity of training, in the form of greater operative experience during residency, had a positive impact on the future use of this specialized surgical technique.