Biomedical subjects

James Becker

Publications and source records attributed to James Becker.

5 recordsLinked to original sources

PubMed2006

A new transcription factor that regulates TNF-alpha gene expression, LITAF, is increased in intestinal tissues from patients with CD and UC.

BACKGROUND: The proinflammatory cytokine tumor necrosis factor-alpha (TNF-alpha) plays a key role in the pathogenesis of Crohn's disease (CD) and ulcerative colitis (UC). Recently, a new transcription factor termed LITAF (lipopolysaccharide-induced TNF-alpha factor) was shown to mediate TNF-alpha expression in human macrophages by direct binding to specific sequences in the promoter region of the TNF-alpha gene. METHODS: In this report, we identified LITAF in resected ileal and colonic tissues from patients with CD and UC by immunohistochemistry, real-time polymerase chain reaction, and Western blot analysis. LITAF expression in inflamed and noninflamed areas of the tissues was compared. RESULTS: This is the first demonstration of LITAF, a newly discovered transcription factor that regulates TNF-alpha gene transcription in ileal and colonic tissues from patients with either CD or UC. LITAF immunostaining was localized to lamina propria macrophages and was markedly increased relative to tissues from controls without inflammatory bowel disease. In patients with CD, a 5-fold increase in LITAF mRNA was measurable in noninflamed colonic tissues compared with controls without inflammatory bowel disease. LITAF mRNA in tissues from inflamed areas of the colon was increased by an additional 60% compared with noninflamed tissues. In patients with UC, LITAF mRNA levels in colonic tissues resected from noninflamed areas were elevated 15-fold above nondisease controls, but they were not different in tissues resected from inflamed areas. Western blot analysis showed that in patients with CD, there was a marked increase in LITAF protein in inflamed areas compared with noninflamed areas. LITAF protein levels were not different between noninflamed and inflamed tissues obtained from patients with UC. TNF-alpha mRNA and protein levels paralleled LITAF. Similarly, in inflamed ileal tissues from patients with CD, LITAF is also localized to lamina propria macrophages. LITAF mRNA and LITAF protein were significantly increased in inflamed ileal tissues compared with noninflamed areas. CONCLUSIONS: LITAF is readily detectable in ileal and colonic tissues from patients with either CD or UC, is significantly elevated above controls, and is localized to macrophages, a major source of TNF-alpha. These data provide strong evidence of a role for LITAF in the pathophysiological regulation of the TNF-alpha gene and underscore the potential value of anti-LITAF strategies in the clinical management of these diseases.

Colitis, Ulcerative↗

PubMed2005

Binding of copper(II) to thyrotropin-releasing hormone (TRH) and its analogs.

Spectroscopy (UV-Vis, (1)H NMR, ESR) and electrochemistry revealed details of the structure of the Cu(II)-TRH (pyroglutamyl-histidyl-prolyl amide) complex. The (1)H NMR spectrum of TRH has been assigned. NMR spectra of TRH in the presence of Cu(II) showed that Cu(II) initially binds TRH through the imidazole. TRH analogs, pGlu-His-Pro-OH, pGlu-(1-Me)His-Pro-amide, pGlu-His-(3,4-dehydro)Pro-amide, pGlu-His-OH, pGlu-Glu-Pro-amide, and pGlu-Phe-Pro-amide provided comparison data. The stoichiometry of the major Cu(II)-TRH complex at pH 7.45 and greater is 1:1. The conditional formation constant (in pH 9.84 borate with 12.0 mM tartrate) for the formation of the complex is above 10(5) M(-1). The coordination starts from the 1-N of the histidyl imidazole, and then proceeds along the backbone involving the deprotonated pGlu-His amide and the lactam nitrogen of the pGlu residue. The fourth equatorial donor is an oxygen donor from water. Hydroxide begins to replace the water before the pH reaches 11. Minority species with stoichiometry of Cu-(TRH)(x) (x = 2-4) probably exist at pH lower than 8.0. In non-buffered aqueous solutions, TRH acts as a monodentate ligand and forms a Cu(II)-(TRH)(4) complex through imidazole nitrogens. All the His-containing analogs behave like TRH in terms of the above properties.

Journal Article↗

PubMed2005

Doped semiconductor nanomaterials.

The development and properties of doped nanomaterials including doped titanium dioxide, doped silicon, and doped cadmium telluride are reviewed, as well as their ultrafast dynamics. Doping nanomaterials provides a flexible way to tune to the properties of the materials while maintaining their high surface areas. The electronic, optical, photochemical, photoelectrochemical, photocatalytic and photoexcited relaxation properties can be tuned towards the desired direction by doping different elements. The materials can be engineered towards specific applications through careful selection of the dopants.

Crystallization↗

PubMed2004

The "cost" of operative training for surgical residents.

HYPOTHESIS: There is an increase in the amount of time required to perform an operation when the procedure involves training a surgical resident. This increased time does not translate into a financial burden for the hospital. DESIGN: Retrospective review of prospectively collected data. During the study period, surgeons and residents were blinded to the study's intent. We compared the operative times of academic surgeons performing 4 common surgical procedures before and after the introduction of a postgraduate year 3 resident into a community teaching hospital. Between January 1, 2001, and June 30, 2002, 4 academic surgeons performed operations without a resident in a community hospital that was recently integrated into a tertiary medical center system. During that period, surgeons operated alone (hernia surgery) or assisted one another (laparoscopic cholecystectomy, colectomy, and carotid endarterectomy). From July 1, 2002, through March 31, 2003, these same 4 surgeons were assisted by a postgraduate year 3 resident on similar procedures. SETTING: Community hospital recently integrated into a tertiary medical center system. PARTICIPANTS: Four experienced academic surgeons operating in the community setting and patients undergoing 1 of 4 surgical procedures (inguinal hernia repair, laparoscopic cholecystectomy, partial colectomy, or carotid endarterectomy) from January 1, 2001, through March 31, 2003. INTERVENTION: The introduction of a postgraduate year 3 surgical resident rotation into a community hospital in which the same academic surgeons had been performing operations without a resident for 18 months. MAIN OUTCOME MEASURES: Mean operating time with and without a postgraduate year 3 resident participating in 4 common surgical procedures. Result For the 4 procedures studied, there was a significant increase in the operative time required to complete such procedures. CONCLUSIONS: There is an increased time cost associated with the operative training of surgical residents. This "cost" primarily impacts the attending surgeon.

Cholecystectomy, Laparoscopic↗

PubMed2004

Suppression of electron spin-echo envelope modulation peaks in double quantum coherence electron spin resonance.

We show the use of the observer blind spots effect for the elimination of electron spin-echo envelope modulation (ESEEM) peaks in double quantum coherence (DQC) electron spin resonance (ESR). The suppression of ESEEM facilitates the routine and unambiguous extraction of distances from DQC-ESR spectra. This is also the first demonstration of this challenging methodology on commercial instrumentation.

Electron Spin Resonance Spectroscopy↗