Biomedical subjects

Robert F Williams

Publications and source records attributed to Robert F Williams.

3 recordsLinked to original sources

PubMed2005

A microfluidic SELEX prototype.

Aptamers are nucleic acid binding species capable of recognizing a wide variety of targets ranging from small organic molecules to supramolecular structures, including organisms. They are isolated from combinatorial libraries of synthetic nucleic acid by an iterative process referred to as SELEX (Systematic Evolution of Ligands by Exponential Enrichment). Here we describe an automated microfluidic, microline-based assembly that uses LabView-controlled actuatable valves and a PCR machine, and which is capable of the selection and synthesis of an anti-lysozyme aptamer as verified by sequence analysis. The microfluidic prototype described is 1) a simple apparatus that is relatively inexpensive to assemble, making automated aptamer selection accessible to many investigators, and 2) useful for the continued "morphing" of macro-->meso-->microfabricated structures until a convergence to a few functional systems evolves and emerges, partly or completely achieving simpler, smaller and more rapid SELEX applications.

Electrophoresis, Agar Gel↗

PubMed2005

Endometrial microstructure after long-term use of a 91-day extended-cycle oral contraceptive regimen.

OBJECTIVE: To assess the effect on the endometrial microstructure of an extended-cycle oral contraceptive (OC) regimen containing ethinyl estradiol (EE) and levonorgestrel (LNG). METHODOLOGY: Subjects received up to four cycles of a 91-day extended-cycle OC regimen (84 consecutive days of monophasic 30 microg EE/150 microg LNG followed by 7 days of placebo). Endometrial biopsies were performed prior to the initiation and at the completion of therapy. All endometrial samples were processed centrally and reviewed by three independent pathologists blinded to treatment groups. RESULTS: Endometrial biopsies were performed in 50 women. In general, samples taken after completion of therapy with no further hormonal exposure demonstrated rapid return to normal endometrial cycling. In contrast, the majority of subjects still on active extended hormonal OC therapy at the time of biopsy had inactive or atrophic endometrium. No intravascular blood clots were observed in any of the specimens. CONCLUSION: The endometrial findings observed in this cohort of women treated with a 91-day extended-cycle OC regimen for up to 1 year showed no significant pathology. Additionally, the endometrium reverted quickly to normal cyclic changes in those subjects who, after completing therapy, elected not to continue with hormonal contraception.

Adolescent↗

PubMed2005

Hemispheric asymmetries and joke comprehension.

Joke comprehension deficits in patients with right hemisphere (RH) damage raise the question of the role of the intact RH in understanding jokes. One suggestion is that semantic, or meaning, activations are different in the RH and LH, and RH meanings are particularly important for joke comprehension. To assess whether hypothesized differences in semantic activation in the two hemispheres were relevant to joke comprehension, we recorded event-related brain potentials (ERPs) as healthy adults read laterally presented "punch words" to one-line jokes and nonjoke controls. Jokes presented to the RVF/LH elicited larger amplitude N400 than the nonjoke endings; when presented to the LVF/RH, the joke and nonjoke endings elicited N400s of equal amplitude. This finding suggests that semantic activations in the two hemispheres do differ, with RH semantic activation facilitating joke comprehension.

Adult↗