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1.  Neurosteroid Analogues. 18. Structure–Activity Studies of ent-Steroid Potentiators of γ-Aminobutyric Acid type A Receptors and Comparison of Their Activities with Those of Alphaxalone and Allopregnanolone 
Journal of medicinal chemistry  2013;57(1):171-190.
A model of the alignment of neurosteroids and ent-neurosteroids at the same binding site on γ-aminobutyric acid type A (GABAA) receptors was evaluated for its ability to identify the structural features in ent-neurosteroids that enhance their activity as positive allosteric modulators of this receptor. Structural features that were identified included: 1) a ketone group at position C-16; 2) an axial 4α-OMe group and 3) a C-18 methyl group. Two ent-steroids were identified that were more potent than the anesthetic steroid alphaxalone in their threshold for and duration of loss of the righting reflex in mice. In tadpoles, loss of righting reflex for these two ent-steroids occurs with EC50 values similar to those found for allopregnanolone. The results indicate that ent-steroids have considerable potential to be developed as anesthetic agents as and drugs to treat brain disorders that are ameliorated by positive allosteric modulators of GABAA receptor function.
PMCID: PMC3951241  PMID: 24328079
2.  Adult Colocolic Intussusception and Literature Review 
Case Reports in Gastroenterology  2013;7(3):381-387.
Intussusception occurs when a proximal segment of the gastrointestinal tract, called intussusceptum, telescopes into the lumen of an adjacent segment, also known as intussuscipiens. Although common in early childhood, intussusceptions are very rare in the adult population. Most intussusceptions in adults are due to a lead point, which is an identifiable pathological abnormality, in opposition to children which there are no identifiable pathological lead points. In contrast to childhood intussusception, in adults it is associated with malignant lesions, particularly in the large bowel rather than in the small bowel. Its preoperative diagnosis and treatment in adults is difficult because of nonspecific abdominal symptom and because it rarely presents with the classic triad of vomiting, abdominal pain and passage of blood per rectum. We present a 63-year-old female with an adenocarcinoma tumor being the lead point in a colocolic intussusception, who was diagnosed preoperatively with computed tomography and had a colonoscopy to rule out obstruction. She underwent right hemicolectomy with side-to-side ileocolic anastomosis and did well postoperatively. In addition, we also review the literature and discuss the value of radiological modalities, location and surgical management to try to improve the preoperative diagnosis. Computed tomography scanning with intravenous contrast is maybe the most accurate modality for diagnosis of intussusceptions in adults, and treatment is usually surgical resection without reduction, since most of the colonic lesions are malignant.
PMCID: PMC3806710  PMID: 24163649
Adult colocolic intussusception; Literature review; Adult; Intussusception; Colon; Adenocarcinoma; Computed tomography scanning
3.  The role of the cantilever in Kelvin probe force microscopy measurements 
The role of the cantilever in quantitative Kelvin probe force microscopy (KPFM) is rigorously analyzed. We use the boundary element method to calculate the point spread function of the measuring probe: Tip and cantilever. The calculations show that the cantilever has a very strong effect on the absolute value of the measured contact potential difference even under ultra-high vacuum conditions, and we demonstrate a good agreement between our model and KPFM measurements in ultra-high vacuum of NaCl monolayers grown on Cu(111). The effect of the oscillating cantilever shape on the KPFM resolution and sensitivity has been calculated and found to be relatively small.
PMCID: PMC3148059  PMID: 21977437
boundary elements method; cantilever; convolution; Kelvin probe force microscopy; point spread function

Results 1-3 (3)