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Biomedical subjects

Stephen A Wilson

Publications and source records attributed to Stephen A Wilson.

At least 19 recordsLinked to original sources
PubMed2007

Impact of the 2004 influenza vaccine shortage on patients from inner city health centers.

In the fall of 2004, the FDA and British authorities suspended the license of one of only two manufacturers that provided the US supply of inactivated influenza vaccine. With a 50% reduction in supply, a severe vaccine shortage resulted. This situation necessitated the development of priority groups for vaccination including those > or =65 years, when ordinarily, influenza vaccine is recommended for those > or =50 years old. A sample of patients > or =50 years old (n = 336), who had been seen at one of four inner-city health centers, was interviewed in summer 2005 using computer-assisted telephone interviewing. Associations of survey responses were examined for three groups: those vaccinated in the 2003-2004 and 2004-2005 influenza seasons (n = 142), those vaccinated in 2003-2004 but not vaccinated in 2004-2005 because of the shortage (n = 63), and those unvaccinated in both seasons (n = 83). Bivariate and multivariate logistic regression analyses were used to determine factors significantly influencing the likelihood of vaccination status. A significantly larger proportion of patients 50-64 years of age were unvaccinated due to the shortage (73%) compared to those who were vaccinated during both seasons (36%, P < 0.001), but there were no racial disparities in vaccination rates. Compared with patients who were vaccinated during both seasons, those who were unvaccinated due to the shortage were more frequently employed, self-reported their health positively, saw their physician less frequently, rated the US government's response to the shortage as "terrible," and blamed the US government for the shortage. Vaccination during the influenza vaccine shortage appears to have followed preferential vaccination of the CDC-established priority group (> or =65 years) and did not result in racial disparities in inner-city health centers.

Black or African American↗
PubMed2006

Low-carbohydrate diets.

Americans spend dollar 33 billion annually on weight loss products and services, and a large portion of this money is spent on low-carbohydrate diets. Because of their higher protein and fat content and lower fiber and carbohydrate content, concerns have been raised about the potential health consequences of low-carbohydrate diets. Published long-term data are lacking. Short-term studies comparing traditional low-fat diets with low-carbohydrate diets found lower triglyceride levels, higher high-density lipoprotein cholesterol levels, similar low-density lipoprotein cholesterol levels, and lower A1C levels in persons on low-carbohydrate diets. These diets induce greater weight loss at three and six months than traditional low-fat diets; however, by one year there is no significant difference in maintained weight loss. Weight loss is directly related to calorie content and the ability to maintain caloric restriction; the proportions of nutrients in the diet are irrelevant. Low-carbohydrate diets had lower dropout rates than low-fat diets in several studies, possibly because of the high protein content and low glycemic index, which can be appetite suppressing. Data indicate that low-carbohydrate diets are a safe, reasonable alternative to low-fat diets for weight loss. Additional studies are needed to investigate the long-term safety and effectiveness of these and other approaches to weight loss.

Diet, Carbohydrate-Restricted↗
PubMed2006

Flextensional ultrasonic piezoelectric micro-motor.

This paper presents the experimental design, construction, and operational characteristics of a new type of standing wave piezoelectric ultrasonic micro-motor. The motor uses a composite stator, consisting of a metallic flex-tensional mode converter, or "cymbal", bonded to a 2-mm-square piezoelectric plate. The cymbal converts contour-mode vibrations of the plate into oscillations in the cymbal, perpendicular to the stator plane. These are further converted into rotational movement in a rotor pressed against the cymbal by means of an elastic-fin friction drive to produce the required rotary actuation. The motor operates on a single-phase electrical supply, and direct control of the output speed and torque can be achieved by adjusting the amplitude and frequency of the supply voltage. Noncontact optical techniques were used to assess the performance of the developed micro-motor. The operational characteristics were developed from the acceleration and deceleration characteristics. No-load output speed (11 rev s(-1)) and stall torque (27 nNm) were derived using high-speed imaging and image analysis. Maximum efficiency was 0.6%.

Computer-Aided Design↗
PubMed2006

Racial differences in beliefs about genetic screening among patients at inner-city neighborhood health centers.

BACKGROUND: Genetic testing has the potential to identify persons at high risk for disease. Given the history of racial disparities in screening, early detection and accessing treatment, understanding racial differences in beliefs about genetics is essential to preventing disparities in some conditions. METHODS: In 2004, a sample of older adult patients from four inner-city health centers was surveyed to assess beliefs about genetic determinants of disease, genetic testing and religion. Logistic regression determined which beliefs were associated with race. RESULTS: Of the 314 respondents, 50% were African Americans. Most respondents thought that sickle cell disease, cystic fibrosis and diabetes are primarily genetic. African Americans were more likely than Caucasians to believe that genetic testing will lead to racial discrimination (Odds ratio (OR): 3.02, 95% confidence interval (CI): 1.5-6.0) and to think that all pregnant women should have genetic tests (OR=3.8, 95% CI: 1.7-8.6). African Americans were more likely to believe that God's Word is the most important source for moral decisions (OR: 3.6, 95% CI :1.5-8.7). CONCLUSION: African Americans and Caucasians differ in beliefs about genetic testing and the basis for moral decision-making. Acknowledging and understanding these differences may lead to better medical care.

Black or African American↗
PubMed2005

TACI is mutant in common variable immunodeficiency and IgA deficiency.

The tumor necrosis factor receptor family member TACI (transmembrane activator and calcium-modulator and cyclophilin ligand interactor) mediates isotype switching in B cells. We found that 4 of 19 unrelated individuals with common variable immunodeficiency (CVID) and 1 of 16 individuals with IgA deficiency (IgAD) had a missense mutation in one allele of TNFRSF13B (encoding TACI). One of the four individuals with CVID had a single nucleotide insertion in the other TNFRSF13B allele. None of these mutations were present in 50 healthy subjects. TNFRSF13B mutations cosegregated with the phenotype of CVID or IgAD in family members of four index individuals that we studied. B cells from individuals with TACI mutations expressed TACI but did not produce IgG and IgA in response to the TACI ligand APRIL, probably reflecting impaired isotype switching. These results suggest that TACI mutations can result in CVID and IgAD.

B-Lymphocytes↗
PubMed2005

TACI and BAFF-R mediate isotype switching in B cells.

The tumor necrosis factor family members BAFF and APRIL induce Ig isotype switching in human B cells. We analyzed the ability of BAFF and APRIL to induce isotype switching in murine B cells to IgG1, IgA, and IgE. APRIL and BAFF each engage two receptors, transmembrane activator and calcium-modulator and cytophilin ligand interactor (TACI) and B cell maturation antigen (BCMA), on B cells. In addition, BAFF engages a third receptor on B cells, BAFF-R. To determine the role of these receptors in isotype switching, we examined B cells from mice deficient in TACI, BCMA, and BAFF-R. The results obtained indicate that both TACI and BAFF-R are able to transduce signals that result in isotype switching.

Animals↗
PubMed2004

Management of corneal abrasions.

Corneal abrasions result from cutting, scratching, or abrading the thin, protective, clear coat of the exposed anterior portion of the ocular epithelium. These injuries cause pain, tearing, photophobia, foreign body sensation, and a gritty feeling. Symptoms can be worsened by exposure to light, blinking, and rubbing the injured surface against the inside of the eyelid. Visualizing the cornea under cobalt-blue filtered light after the application of fluorescein can confirm the diagnosis. Most corneal abrasions heal in 24 to 72 hours and rarely progress to corneal erosion or infection. Although eye patching traditionally has been recommended in the treatment of corneal abrasions, multiple well-designed studies show that patching does not help and may hinder healing. Topical mydriatics also are not beneficial. Initial treatment should be symptomatic, consisting of foreign body removal and analgesia with topical nonsteroidal anti-inflammatory drugs or oral analgesics; topical antibiotics also may be used. Corneal abrasions can be avoided through the use of protective eyewear.

Analgesics↗
PubMed2004

Physician and practice factors related to influenza vaccination among the elderly.

BACKGROUND: Influenza vaccination rates among adults, especially in minority populations, remain below national goals of 90%. This study investigated in diverse settings, facilitators of and barriers to patient influenza vaccination from the physician's perspective. METHODS: Two-stage, stratified, random-cluster sampling was employed to select 71 clinicians from inner-city, rural, suburban, and Veterans Affairs (VA) practices, and a random sample of 925 of their patients aged >/=65 years. Questionnaires and interviews based on the PRECEDE-PROCEED framework assessed clinician factors. Associations among clinician beliefs, practice characteristics, patient beliefs, and self-reported influenza vaccination status were determined. RESULTS: The clinician response rate was 85% (60/71). Several factors of the PRECEDE-PROCEED framework were associated with higher influenza vaccination rates. For instance, patients at practices with express vaccination clinics had higher vaccination rates than at clinics without such immunization programs (87% v 76%, p =0.01). Using multivariate models, influenza vaccination status was related to several patient factors, including plans to receive influenza vaccination next year (p <0.001); belief that those who are not vaccinated will contract influenza (p =0.049); and history of being screened for colon cancer (p =0.023). Influenza vaccination status was also related to several physician factors, including awareness of recommendation to vaccinate asthmatics (p =0.024); agreement with these recommendations (p =0.004); and practice type and setting ("strata"), of which the VA was highest. CONCLUSION: Through proactive office systems and education, physicians may influence patients' intentions to be vaccinated and thereby increase influenza vaccination rates.

Aged↗
PubMed2004

Flextensional ultrasonic motor using the contour mode of a square piezoelectric plate.

This paper presents the design, fabrication, and characterization of a new type of standing wave piezoelectric ultrasonic motor. The motor uses a metallic flextensional amplifier, or cymbal, to convert the contour mode vibrations of a square piezoelectric ceramic plate into flexural oscillations, which are further converted to produce rotary actuation by means of an elastic-fin friction drive. The motor operates on a single-phase electrical supply. A beryllium copper rotor design with three-fin configuration was adopted, and the geometry was varied to include different material thicknesses, fin lengths, and inclinations. The best stall torque and no load speed for a 25-mm square motor were 0.72 Nmm and 895 r/minute, respectively. The behavior of the stator structure was analyzed by ANSYS finite element software using harmonic and modal analyses. The vibration mode estimated by finite element modeling (FEM) was confirmed by laser Doppler vibration measurements.

Journal Article↗
PubMed2003

Barriers and facilitators of pneumococcal vaccination among the elderly.

Despite the burden of disease caused by pneumococcus, adult immunization rates are modest. To understand barriers in diverse settings, we surveyed patients age > or =66 years at: (1) inner-city health centers; (2) Veterans Affairs (VA) outpatient clinics; (3) rural practices; and (4) suburban practices. Among the 1007 respondents, self-reported pneumococcal vaccination rates were: 85% VA; 62% rural; 66% suburban; and 57% inner-city with substantial variability among practices. Half of the unvaccinated (50%) did not know they needed vaccination. Most vaccinees (90%) thought that their doctor believed they should be vaccinated, compared with 23% of the unvaccinated (P<0.0001). More of the vaccinees (75%) believed that the vaccine "keeps a person from getting pneumonia" than the unvaccinated (54%; P=0.0001). In regression analysis, predictors of vaccination included: belief that doctor recommends vaccine, feeling that vaccination is wise, recommendation by someone in the physician's office, and receipt of influenza vaccine.

Aged↗
PubMed2003

What affects influenza vaccination rates among older patients? An analysis from inner-city, suburban, rural, and Veterans Affairs practices.

BACKGROUND: Despite strong evidence of the effectiveness of influenza vaccination, immunization rates have reached a plateau that is below the 2010 national goals. Our objective was to identify facilitators of, and barriers to, vaccination in diverse groups of older patients. METHODS: A survey was conducted in 2000 by computer-assisted telephone interviewing of patients from inner-city health centers, Veterans Affairs (VA) outpatient clinics, rural practices, and suburban practices. The inclusion criteria were age > or =66 years and an office visit after September 30, 1998. RESULTS: Overall, 1007 (73%) interviews were completed among 1383 patients. Influenza vaccination rates were 91% at VA clinics, 79% at rural practices, 79% at suburban practices, and 67% at inner-city health centers. There was substantial variability in vaccination rates among practices, except at the VA. Nearly all persons who were vaccinated reported that their physicians recommended influenza vaccinations, compared with 63% of unvaccinated patients (P <0.001). Thirty-eight percent of unvaccinated patients were concerned that they would get influenza from the vaccine, compared with only 6% of vaccinated persons (P <0.001). Sixty-three percent of those vaccinated, in contrast with 22% of unvaccinated persons, thought that an unvaccinated person would probably contract influenza (P <0.001). CONCLUSION: Older patients need intentional messages from physicians that recommend vaccination. Furthermore, more patient education is needed to counter myths about adverse reactions.

Aged↗
PubMed2003

Tailored interventions to increase influenza vaccination in neighborhood health centers serving the disadvantaged.

OBJECTIVES: We designed and evaluated interventions to increase adult immunizations within inner-city health centers. METHODS: Interventions included reminders, standing orders, and walk-in "flu shot clinics." Patients were surveyed and records evaluated. RESULTS: Records from 1 center showed that immunization rates increased from 24% to 30% (P <.001) for patients aged 50 to 64 years and from 45% to 53% for patients aged 65 years and older (P <.001). Self-reported vaccination rates did not increase. In logistic regression analyses, the strongest predictor of vaccination among patients aged 50 to 64 years was the belief that unvaccinated persons will contract influenza (odds ratio [OR] = 5.4; 95% confidence interval [CI] = 2.4, 12.0). Among patients aged 65 years and older, the strongest predictor of vaccination was the belief that friends/relatives thought that they should be vaccinated (OR = 9.7; 95% CI = 4.2, 22.3). CONCLUSIONS: Tailored interventions can improve immunization rates at inner-city health centers.

Community Health Centers↗