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Biomedical subjects

E Snell

Publications and source records attributed to E Snell.

12 recordsLinked to original sources

Urban issues in health promotion strategies.

The powerful influence of behavioral choices on health status is well established. The implications and challenges for urban populations are formidable. Understanding urban environments will better prepare health promotion professionals to deal effectively with the forces affecting health-related behaviors. In thinking about urban health promotion in the United States, researchers often distinguish between 2 frameworks; one contending with urbanization, which affects most of us, and another contending with inner-city environments, where many of the deepest needs are. Urbanization confers both benefits and liabilities, but the single greatest challenge for health promotion may lie in reestablishing positive social connections. In contrast, 2 key features of the inner-city environment may be the negative ecological forces within neighborhoods and the lack of control over one's fate. Too often, prescriptions for the inner city stereotype its problems and ignore its strengths. For the inner city, important foundation stones for the future include ways to build on these strengths through positive connections and increased community control through coalition building.

Health Promotion↗

Baculovirus expression of the respiratory syncytial virus fusion protein using Trichoplusia ni insect cells.

Respiratory syncytial virus (RSV) is a major viral pathogen responsible for severe respiratory tract infections in infants, young children, and the elderly. The RSV fusion (F) protein is highly conserved among RSV subgroups A and B and is the major protective immunogen. A genetically-engineered version of the RSV F protein was produced in insect cells using the baculovirus expression system. To express a secreted form of this protein, the transmembrane domain was eliminated by removing the region of the gene encoding 48 amino acids at the C-terminus. Production of the truncated RSV F protein (RSV-Fs) was compared in two different insect cell lines, Spodoptera frugiperda (Sf9) and Trichoplusia ni (High Five). The yield of RSV-Fs secreted from High Five insect cells was over 7-fold higher than that from Sf9 insect cells. Processing of the RSV-Fs protein was also different in the two insect cell lines. N-terminal sequencing demonstrated that while most of the RSV-Fs protein secreted by High Five cells was correctly processed at the F2-F1 proteolytic cleavage site, most of the RSV-Fs protein secreted by Sf9 cells was unprocessed or incorrectly processed. Antigenicity of the major RSV F neutralization epitopes was maintained in the RSV-Fs protein secreted from High Five cells. The RSV-specific neutralizing antibody titres in the sera of cotton rats immunized with the RSV-Fs protein were equivalent to those in the sera of animals intranasally inoculated with live RSV. Animals immunized with either live RSV or the immunoaffinity purified RSV-Fs protein from High Five cells were completely protected against live virus challenge.

Animals↗

Image-plate synchrotron laue data collection and subsequent structural analysis of a small test crystal of a nickel-containing aluminophosphate.

Image plates have advantages over photographic films, which include wider dynamic range, higher detector quantum efficiency, reduced exposure time and large size. In this study, an on-line image-plate system has been used to record crystallographic data from a small crystal. In particular, synchrotron Laue data were recorded with lambda(min) = 0.455, lambda(max) = 1.180 A, in 20 images 10 degrees apart and with an exposure time of 0.3 s each from a crystal (0.02 x 0.05 x 0.25 mm) of a nickel-containing aluminophosphate, NiAPO. The Laue data were analyzed with the Daresbury Laue software, including the application of an absorption correction. The structure was solved by a combination of the Patterson method and successive difference Fourier calculations using SHELXS86 and SHELXL93; the final R value for 1934 unique reflections (all data) and 310 parameters was 7.90%. The structure agrees with that determined by monochromatic diffractometry using the same crystal and reported by Helliwell, Gallois, Kariuki, Kaucic & Helliwell [Acta Cryst. (1993), B49, 420-428] with an r.m.s. deviation of 0.03 A. Hence, this study shows the image-plate device to be very effective for synchrotron data collection and subsequent structure analysis from small crystals, i.e. 0.02 x 0.05 x 0.25 mm, in chemical crystallography as well as providing further confirmation of the practicability of Laue data in structure solution and refinement.

Journal Article↗

A survey of rubella antibodies in health personnel and a report of vaccine trial.

Five hundred and seventy female health science personnel between the ages of 18 and 25 years were examined for antibodies to the rubella virus by the hemagglutination inhibition technique. Approximately 90% of the subjects had a titre of 1:20 or higher. The geometric mean titre of the positive sera was 1:251. Sixty-four of the 77 persons with an antibody of 1:20 or less volunteered to take the vaccine and were examined six weeks later for the development of antibodies. The conversion rate for the 51 persons who were negative at the dilution of 1:20 at the outset was 94%; the rate of antibody increment for the 13 persons who were positive at 1:20 at the outset was 77%. Among the 51 persons who developed antibodies, the geometric mean titre was 1:57 and among the other 13 it was 1:49. Although the trial was conducted in adult females, the number of side effects from the vaccine was remarkably scanty and insignificant. This trial would seem to emphasize the importance of avoiding the use of rubella vaccine in women of child-bearing age without first excluding pregnancy with meticulous care and using active and controllable contraceptive methods for the two months following vaccination.

Adolescent↗

The effect of allograft meniscal replacement on intraarticular contact area and pressures in the human knee. A biomechanical study.

To define the biomechanical effects of total lateral meniscectomy and of subsequent lateral meniscal allograft replacement on load transmission and distribution across the human knee, we mounted 10 fresh-frozen young human cadaveric knees on a mechanical testing system. Peak pressure and contact area profiles were determined at 0 degrees, 30 degrees, and 60 degrees of knee flexion using pressure-sensitive film and a densitometer. Load transmission profiles were determined for each knee in a sequential test order: 1) intact knee, 2) after lateral meniscectomy, 3) after implantation of size-matched meniscal allograft fixed with bone plugs, and 4) after release of the anterior and posterior horn attachments of the allograft. Total lateral meniscectomy resulted in a 45% to 50% decrease in total contact area. Allograft replacement increased total contact area by 42% to 65% as compared with total meniscectomy at all flexion angles. After release of the anterior and posterior horn attachments, contact area was identical to that after total meniscectomy. Total lateral meniscectomy resulted in a 235% to 335% increase in peak local contact pressure. Allograft replacement decreased these pressures by 55% to 65% at all flexion angles, but they remained significantly greater than those in the intact state. After release of the anterior and posterior horn attachments, contact pressures were identical to those after total meniscectomy. Compared with total meniscectomy, meniscal allograft transplantation significantly increases contact area and decreases peak local contact pressures, but any biomechanical advantages are lost without bone plug fixation of the anterior and posterior horns.

Adult↗