Prevalence of Appendicoliths Detected at CT in Adults With Suspected Appendicitis.

OBJECTIVE. With heightened interest in nonoperative antibiotic management of uncomplicated appendicitis, appendicoliths become a more relevant issue, and because of higher failure rates their presence may be considered a contraindication. The purpose of this study was to investigate the prevalence of appendicoliths at CT in adults with suspected appendicitis. MATERIALS AND METHODS. Among adults undergoing MDCT for suspected appendicitis, 248 patients (134 women, 114 men; mean age, 35.2 years) consecutively registered over a 3-year period constituted a cohort with surgically proven appendicitis. A cohort of 248 patients (175 women, 73 men; mean age, 37.7 years) without appendicitis consecutively registered over a 1-year period served as control subjects. CT examinations were reviewed for the presence, size, and attenuation of appendicoliths and whether the appendicoliths were obstructing. In the cohort with appendicitis, degree of inflammation (3-point scale) and likelihood for perforation (5-point scale) were scored. RESULTS. The prevalence of appendicoliths at CT was 38.7% (96/248) among patients with appendicitis and 4.4% (11/248) among control subjects (p < .001). Among the 96 patients with appendicitis who had visible appendicoliths, mean width, length, and maximum attenuation of the dominant appendicolith were 6.0 mm, 8.2 mm, and 313 HU, respectively. In 70.8% (68/96) of patients appendicoliths were obstructing, and 32.3% (31/96) of patients had more than one appendicolith. Inflammation (1.75 vs 1.43) and likelihood of perforation (2.07 vs 1.51) (p < .05) scores were higher among patients with appendicitis who had appendicoliths. Extraluminal appendicoliths were seen in five cases of perforated appendicitis. CONCLUSION. Appendicoliths were identified at CT in nearly 40% of adults with proven appendicitis, compared with slightly more than 4% of those without appendicitis, and were associated with increased inflammation and risk of perforation.

Stump Appendicitis: Clinical and CT Findings.

OBJECTIVE. Recurrent inflammation of the appendiceal stump after appendectomy is rare; published case series have included no more than six patients. The purpose of this study was to report the clinical and CT findings in a larger original series. MATERIALS AND METHODS. A combined PACS and electronic medical record search identified the cases of 14 patients (nine men, five women; mean age, 42.8 years) with a confident diagnosis of stump appendicitis evaluated at CT. In seven cases, CT images obtained at the initial presentation of appendicitis were available for review. Relevant clinical and CT findings were reviewed by three abdominal radiologists in consensus. RESULTS. The mean time interval between initial appendectomy and stump appendicitis was 5.1 years (range, 5 weeks-17.5 years); seven cases occurred within 1 year of appendectomy. Ten (71%) of initial appendectomies were performed by a laparoscopic approach. CT showed the mean appendiceal stump length was 3.2 cm (range, 1.3-7.0 cm); residual stump length measured 2 cm or longer in all but one case. Appendicoliths were identified at the stump in seven (50%) cases; the mean diameter was 0.9 cm and mean maximal attenuation, 247 HU. Extensive inflammatory changes surrounded the appendiceal stump at CT in all cases, including peristump abscess in four (29%) cases. Seven of the 14 patients (50%) went on to open surgical management with either remnant appendectomy or partial ileocecectomy. CONCLUSION. Stump appendicitis has a characteristic CT appearance and may occur within the first year after appendectomy or many years later. A long (≥ 2 cm) appendiceal stump from laparoscopic appendectomy and retained appendicolith may predispose adult patients to recurrent obstruction and inflammation.

Carcinoma epidermoide semidiferenciado de piso de boca y reborde residual: reporte de un caso / Semi-differentiated squamous cell carcinoma of the floor of the mouth and residual ridge: report of a case

El carcinoma epidermoide, es una neoplasia maligna de mayor incidencia de la cavidad bucal que representa el 55 por ciento de todos los tumores de esta región. El 68-72 por ciento de estos pacientes presenta etapas locorregionales avanzadas en el momento del diagnóstico. El objetivo de este trabajo es el de presentar un caso de un carcinoma epidermoide semidiferenciado de piso de boca y reborde residual mandibular anterior, tratado con submandibulectomía segmentaria y reconstrucción con osteosíntesis rígida...

Computational structural analysis of an anti-L-amino acid antibody and inversion of its stereoselectivity.

The binding site of a monoclonal anti-L-amino acid antibody (anti-L-AA) was modeled using the program SWISS-MODEL. Docking experiments with the enantiomers of phenylalanine revealed that the antibody interacts with L-phenylalanine via hydrogen bonds and hydrophobic contacts, whereas the D-enantiomer is rejected due to steric hindrance. Comparison of the sequences of this antibody and an anti-D-amino acid antibody (anti-D-AA) indicates that both immunoglobulins derived from the same germline progenitor. Substitution of four amino acids residues, three in the framework and one in the complementarity determining regions (CDRs), allowed in silico conversion of the anti-L-AA into an antibody that stereoselectively binds D-phenylalanine.

Investigation of the stereoselectivity of an anti-amino acid antibody using molecular modeling and ligand docking.

The structure of the binding site of the stereoselective anti-D-amino acid antibody 67.36 was modeled utilizing web antibody modeling (WAM) and SWISS-MODEL. Although docking experiments performed with an aromatic amino acid as model ligand were unsuccessful with the WAM structure, ligand binding was achieved with the SWISS-MODEL structure. Incorporation of side-chain flexibility within the binding site resulted in a protein structure that stereoselectively binds to the D-enantiomer of the model ligand. In addition to four hydrogen bonds that are formed between amino acid residues in the binding site and the ligand, a number of hydrophobic interactions are involved in the formation of the antibody-ligand complex. The aromatic side chain of the ligand interacts with a tryptophan and a tyrosine residue in the binding site through pi-pi stacking. Fluorescence spectroscopic investigations also suggest the presence of tryptophan residues in the binding site, as ligand binding causes an enhancement of the antibody's intrinsic fluorescence at an emission wavelength of 350 nm. Based on the modeled antibody structure, the L-enantiomer of the model ligand cannot access the binding site due to steric hindrance. Additional docking experiments performed with D-phenylalanine and D-norvaline showed that these ligands are bound to the antibody in a way analogous to the D-enantiomer of the model ligand.

New developments in the production and use of stereoselective antibodies.

This article describes the production of stereoselective antibodies using both classical immunological and modern molecular biological techniques. Stereoselective antibodies against alpha-hydroxy acids were raised in rabbits and mice and compared with previously produced anti-alpha-amino acid antibodies. It was found that both types of antibodies combine stereoselectivity with class-specificity. Sequence analyses revealed that antibodies with opposing stereoselectivities can be formed during the affinity maturation process from a common progenitor or independently using nonhomologous binding sites. For the first time, phage display was employed to obtain stereoselective antibody fragments. The versatility of stereoselective antibodies as chiral selectors was demonstrated by applying them in several immunosensors and in chiral chromatography. A simple, membrane-based optical sensor allowed detection of enantiomeric impurities at the 1/2,000 level (99.9% ee). Silica-based antibody chiral stationary phases could be used for enantiomer separation of aliphatic amino acids in standard-sized columns, while miniaturized columns allowed interfacing with an MS-detector.