Biomedical subjects

S L Riley

Publications and source records attributed to S L Riley.

4 recordsLinked to original sources

PubMed2000

Student performances on Step 1 and Step 2 of the United States Medical Licensing Examination following implementation of a problem-based learning curriculum.

PURPOSE: To examine students' performances on Step 1 and Step 2 of the United States Medical Licensing Examination (USMLE) following the implementation of a problem-based learning curriculum. METHOD: Performances on Step 1 of the USMLE for four classes at the University of Missouri-Columbia School of Medicine that completed a new problem-based learning curriculum (1997, 1998, 1999, and 2000) were compared with those of the last two classes to learn in the traditional curriculum (1995 and 1996). Performances on Step 2 of the USMLE for the classes of 1997, 1998, and 1999 were also compared with those of the classes of 1995 and 1996. The authors analyzed matriculation data (GPAs and MCAT scores) for all six classes. They compared all data with those of U.S. and Canadian first-time USMLE takers. RESULTS: The mean scores were higher on USMLE Step 1 for classes in the problem-based learning curriculum than for classes in the traditional curriculum. The mean scores for Step 2 were above the national mean for classes in the revised curriculum and below the national mean for classes in the traditional curriculum. The admission profiles of these classes were essentially the same before and after the change in curriculum. CONCLUSIONS: Major PBL revisions of the curriculum did not compromise the performances of medical students on the licensing examinations; in fact, they may have contributed to higher scores.

Canada↗

PubMed1994

The effect of the tetrathyridia of Mesocestoides corti on the livers and peripheral blood of three different strains of mice.

Three strains of male and female mice, CFLP, BALB/c and CBA/ca, were infected i.p. with the tetrathyridia of Mesocestoides corti and examined in groups of 5 at 0, 7, 14, 21, 28 and 42 days post-infection. At post-mortem the numbers of parasites both loose in the peritoneal cavity and in the liver tissue were counted, the livers weighted fresh and sections of liver stained to examine the inflammatory response, encapsulation of the tetrathyridia and for eosinophils, neutrophils, mast cells and plasma cells. BALB/c mice had significantly more parasites loose in the peritoneal cavity than CFLP and CBA/ca mice. Infected livers of all three strains were significantly heavier than control livers; the heaviest livers were those of the CFLP followed by the CBA/ca mice which also showed the greatest rate of weight increase. The tetrathyridia from the peritoneal cavities of the CBA/ca and CFLP mice were covered with a 'mucilage-like' substance. Tetrathyridia within the host capsules of the CBA/ca mice contained host cells. There was no strain difference with regard to numbers of tetrathyridia in the liver but male mice harboured significantly more parasites than females. Differences in the numbers of cell types within the liver were detected between the strains but no one strain showed any consistent pattern. There was an overall increase in total white blood counts as well as an increase in the number of eosinophils, monocytes, neutrophils and lymphocytes during the course of the infection.

Animals↗

PubMed1989

Effects of stimulation by cochlear implant on the cochlear nerve.

Degeneration of the cochlear nerve before and after placement of the cochlear implant might influence the efficacy of the device. We examined histological characteristics, including the caliber of the cochlear nerve fibers of the central segment proximal to the porus acusticus, in three profoundly deaf patients. Two of them used a cochlear implant for many years longer in one ear than in the other, and one used an implant in one ear only. No qualitative or quantitative differences between the two sides were found. However, in all three cases we found that the cochlear nerves on both sides were substantially degenerated. These results indicated no noticeable effects of stimulation by the cochlear implant on the central portion of the cochlear nerve.

Adult↗

PubMedDate not supplied

Formulation of PEG-based hydrogels affects tissue-engineered cartilage construct characteristics.

The limited supply of cartilage tissue with appropriate sizes and shapes needed for reconstruction and repair has stimulated research in the area of hydrogels as scaffolds for cartilage tissue engineering. In this study we demonstrate that poly(ethylene glycol) (PEG)-based semi-interpenetrating (sIPN) network hydrogels, made with a crosslinkable poly(ethylene glycol)-dimethacrylate (PEGDM) component and a non-crosslinkable interpenetration poly(ethylene oxide) (PEO) component, and seeded with chondrocytes support cartilage construct growth having nominal thicknesses of 6 mm and relatively uniform safranin-O stained matrix when cultured statically, unlike constructs grown with prefabricated macroporous scaffolds. Even though changing the molecular weight of the PEO from 100 to 20 kDa reduces the viscosity of the precursor polymer solution, we have demonstrated that it does not appear to affect the histological or biochemical characteristics of cartilaginous constructs. Extracellular matrix (ECM) accumulation and the spatial uniformity of the ECM deposited by the embedded chondrocytes decreased, and hydrogel compressive properties increased, as the ratio of the PEGDM:PEO in the hydrogel formulation increased (from 30:70 to 100:0 PEGDM:PEO). Total collagen and glycosaminoglycan contents per dry weight were highest using the 30:70 PEGDM:PEO formulation (24.4+/-3.5% and 7.1+/-0.9%, respectively). The highest equilibrium compressive modulus was obtained using the 100:0 PEGDM:PEO formulation (0.32+/-0.07 MPa), which is similar to the compressive modulus of native articular cartilage. These results suggest that the versatility of PEG-based sIPN hydrogels makes them an attractive scaffold for tissue engineering of cartilage.

Journal Article↗