Biomedical subjects

S B Johnson

Publications and source records attributed to S B Johnson.

At least 19 recordsLinked to original sources

PubMed2006

Association of K121Q polymorphism in ENPP1 (PC-1) with BMI in Caucasian and African-American adults.

OBJECTIVE: To test for association of the ectonucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1) K121Q polymorphism with body mass index (BMI) and diabetes in a large sample of Caucasians and African-Americans by selectively genotyping individuals at the extremes of the phenotypic distribution. SUBJECTS: Subsets comprising the extremes of the BMI distribution (10th-20th and above the 90th BMI percentile for Caucasians and between the 10th-30th and above the 80th percentile for African-Americans) from a group of 10,260 Caucasian and 2268 African-American adults participating in New York Cancer Project were studied. METHODS: Subjects were genotyped for the ENPP1 K121Q polymorphism by pyrosequencing and tested for association with BMI and diabetes by regression analysis. RESULTS: Regression analysis with BMI as the dependent variable demonstrated a significant association (P = 0.02) of genotype at K121Q with BMI, with no significant race-by-genotype interaction (P = 0.30). Compared with Q/Q or Q/K individuals, the K/K individuals had a BMI approximately 1.3 kg/m2 higher, without effects of age, gender or race. By logistic regression analysis, the K121Q alleles had no significant effect on diabetes status (P = 0.37) in obese subjects. CONCLUSION: In both Caucasians and African-Americans, the K121 polymorphism in ENPP1 was associated with increased BMI, but not with diabetes.

Adult↗

PubMed2004

Urban youths' perspectives on violence and the necessity of fighting.

OBJECTIVES: To assess youth perceptions of the causes and consequences of violence generally, the causes and consequences of fighting specifically, and to determine how best to approach fighting in the context of violence prevention activities. METHODS: Thirteen structured focus group interviews with youths from three high violence urban settings: a large, urban high school, a training center for disadvantaged youths, and a school for adjudicated youths. Participants were 120 urban, predominately African-American youths and young adults ages 14-22 years (mean: 17.2 years). Seven focus groups were conducted with females, and six with males. RESULTS: Adolescents identified the causes of violence on multiple levels including: individual, family, interpersonal, and community level factors. Most youths (89%) had been in a physical fight. Participants felt that fighting was not "right", but identified situations in which it was necessary. Specifically, fighting was used as a problem solving tool, and could prevent escalation of violence. Youths felt that the adults in their lives, including physicians, were generally ill equipped to give advice about violence, as adults' experiences were so removed from their own. Participants looked to experienced role models to offer problem solving and harm reduction strategies. Youths were open to receiving anticipatory guidance about violence and fighting from primary care physicians they felt comfortable with, and who showed respect for their experiences. CONCLUSIONS: Interventions that include blanket admonitions against fighting should be reassessed in light of youth perceptions that fighting plays a complex role in both inciting and preventing more serious violence.

Adolescent↗

PubMed2003

Unintentional and undetermined firearm related deaths: a preventable death analysis for three safety devices.

OBJECTIVE: To determine the proportion of unintentional and undetermined firearm related deaths preventable by three safety devices: personalization devices, loaded chamber indicators (LCIs), and magazine safeties. A personalized gun will operate only for an authorized user, a LCI indicates when the gun contains ammunition, and a magazine safety prevents the gun from firing when the ammunition magazine is removed. DESIGN: Information about all unintentional and undetermined firearm deaths from 1991-98 was obtained from the Office of the Chief Medical Examiner for Maryland, and from the Wisconsin Firearm Injury Reporting System for Milwaukee. Data regarding the victim, shooter, weapon, and circumstances were abstracted. Coding rules to classify each death as preventable, possibly preventable, or not preventable by each of the three safety devices were also applied. RESULTS: There were a total of 117 firearm related deaths in our sample, 95 (81%) involving handguns. Forty three deaths (37%) were classified as preventable by a personalized gun, 23 (20%) by a LCI, and five (4%) by a magazine safety. Overall, 52 deaths (44%) were preventable by at least one safety device. Deaths involving children 0-17 (relative risk (RR) 3.3, 95% confidence interval (CI) 2.1 to 5.1) and handguns (RR 8.1, 95% CI 1.2 to 53.5) were more likely to be preventable. Projecting the findings to the entire United States, an estimated 442 deaths might have been prevented in 2000 had all guns been equipped with these safety devices. CONCLUSION: Incorporating safety devices into firearms is an important injury intervention, with the potential to save hundreds of lives each year.

Adolescent↗

PubMed2001

Accessing heterogeneous sources of evidence to answer clinical questions.

The large and rapidly growing number of information sources relevant to health care, and the increasing amounts of new evidence produced by researchers, are improving the access of professionals and students to valuable information. However, seeking and filtering useful, valid information can be still very difficult. An online information system that conducts searches based on individual patient data can have a beneficial influence on the particular patient's outcome and educate the healthcare worker. In this paper, we describe the underlying model for a system that aims to facilitate the search for evidence based on clinicians' needs. This paper reviews studies of information needs of clinicians, describes principles of information retrieval, and examines the role that standardized terminologies can play in the integration between a clinical system and literature resources, as well as in the information retrieval process. The paper also describes a model for a digital library system that supports the integration of clinical systems with online information sources, making use of information available in the electronic medical record to enhance searches and information retrieval. The model builds on several different, previously developed techniques to identify information themes that are relevant to specific clinical data. Using a framework of evidence-based practice, the system generates well-structured questions with the intent of enhancing information retrieval. We believe that by helping clinicians to pose well-structured clinical queries and including in them relevant information from individual patients' medical records, we can enhance information retrieval and thus can improve patient-care.

Computational Biology↗

PubMed2001

Altered response to ibutilide in a heart failure model.

OBJECTIVE: Despite the frequent use of anti-arrhythmic drugs in the general population, the electrophysiologic effects of these agents have not been elucidated in congestive heart failure (CHF). METHODS: To examine the impact of left ventricular dysfunction on actions of type III anti-arrhythmic drugs, we evaluated the actions of ibutilide in a canine model of pacing-induced dilated cardiomyopathy. Following ablation of the atrioventricular node, effects on action potential duration at 90% (APD(90)) were compared in vivo, between eight CHF animals and seven controls. Monophasic action potential recordings were obtained from right and left ventricular endocardium/epicardium during and after three doses of ibutilide (0. 01, 0.02 and 0.05 mg/kg), at pacing cycle lengths of 300-1000 ms. RESULTS: APD(90) prolongation with ibutilide (0.01 mg/kg) was significantly greater in CHF vs. controls (P=0.0026, ANOVA). However, plasma ibutilide levels at this dose, were not significantly different between the two groups. In CHF, maximal effects were observed at the lowest dose, whereas effects were gradual and dose-dependent in controls. With ibutilide administration (0.01 mg/kg), an increased dispersion of left-right ventricular APD(90) was observed in CHF, but not in controls (P=0.03). A trend was observed, for increased incidence of non-sustained polymorphic ventricular tachycardia in CHF. CONCLUSIONS: In the presence of CHF, the actions of ibutilide are altered significantly. These findings may reflect altered tissue effects, as a consequence of myocardial electrical remodeling in CHF.

Action Potentials↗

PubMed2001

Psychological response to prenatal genetic counseling and amniocentesis.

The purpose of the present study was to characterize the psychological status (attitudes toward selective abortion, perceived risk, comprehension, patient satisfaction, coping, and state anxiety) of pregnant women at increased risk for fetal genetic anomalies who were referred for prenatal genetic counseling and amniocentesis; to determine which of these factors would predict amniocentesis use; and to identify patient outcomes associated with counseling and testing. Participants were 129 women aged 18 years and older who had one or more fetal genetic risk factors. All were recruited from an urban women's health clinic. The results revealed elevated perceptions of risk and moderate state anxiety despite adequate comprehension of, and patient satisfaction with, the process and content of genetic counseling. Approximately 78% agreed to testing; those who consented were more likely to hold favorable attitudes toward abortion than those who refused. Post-counseling, women experienced decrease in their perceived risk of having a baby born with a birth defect although perceived risk estimates remained higher than actual risks. Anxiety was clinically elevated and highest at the pre-counseling stage, though it dissipated to normal levels over time. Previous experience with prenatal diagnostic testing, increased perceived risk of a birth anomaly, and favorable attitudes toward abortion were independently associated with increased pre-counseling anxiety. Women who were more anxious pre-counseling remained more anxious post-counseling. Coping (high versus low monitoring) was unrelated to anxiety. These findings suggest that women who participate in prenatal counseling and testing may be subject to experience distress and unrealistic perceptions of their risk and may benefit from interventions designed to lessen these states.

Abortion, Induced↗

PubMed2001

Amplified effects of d,l-sotalol in canine dilated cardiomyopathy.

Despite the presence of well-described cardiac repolarization abnormalities in heart failure, d,l-sotalol effects on cardiac repolarization have not been evaluated in animal models of CHF. The authors hypothesized that the d,l-sotalol effects on cardiac repolarization are altered in canine dilated cardiomyopathy when compared to controls. Effects of d,l-sotalol were compared in seven dogs with tachycardia induced cardiomyopathy (CHF) and six control animals. In an open-chest model, contact monophasic action potential recordings were obtained from RV and LV endocardium/epicardium during and after two doses of d,l-sotalol (1 mg/kg and 3 mg/kg, each over 20 minutes). Effects of d,l-sotalol on action potential duration at 90% repolarization (APD90) were examined at pacing cycle lengths of 300-1,000 ms. Plasma d,l-sotalol levels were measured at baseline, 10, and 40 minutes following each dose. Prolongation of APD90 by d,l-sotalol, was significantly exaggerated in CHF animals versus controls (P < 0.05, ANOVA). These differences were magnified at slow heart rates (P < 0.05, ANOVA). There were no significant differences in plasma d,l-sotalol levels between the two groups. Effects of d,l-sotalol on cardiac repolarization are exaggerated in CHF without significant alterations in plasma drug levels. While using d,l-sotalol in heart failure, independent additional effects due to ventricular electrical remodeling may be a consideration.

Action Potentials↗

PubMed2001

Maternal feeding practices and beliefs and their relationships to overweight in early childhood.

To better explore possible factors that may lead to childhood obesity, we developed and analyzed two new instruments that assess maternal feeding practices and beliefs. The Infant Feeding Questionnaire (IFQ) assesses feeding during the entire first year of life and was administered to 453 mothers of children 11 to 23 months old. The Preschooler Feeding Questionnaire (PFQ) assesses feeding of young children between the ages of 2 to 5 years and was administered to 634 mothers of children this age. Each questionnaire was factor analyzed and mean factor scores were calculated and linked with the children's measured and mothers' self-reported weight and height. Mean factor scores from the IFQ and PFQ were compared between mothers who were obese (body mass index > or = 30 kg/m2) and those who were nonobese, between those who did and those who did not have an overweight child (weight-for-height > or = 90th percentile), and between those who had a low income (< or = 185% of the poverty level) and those who had a high income. To control for confounding variables and to detect interaction among variables, hierarchical linear regression was used. Results from this study did not suggest that there is a particular "feeding style" that is associated with overweight in young children; however, there were differences found in feeding behaviors between high and low income mothers.

Attitude to Health↗

PubMed2001

Clinical testing results and high patient satisfaction with a new needle-free device for growth hormone in young children.

Fifty children ages 4-10 yr with type 1 diabetes mellitus volunteered to participate in a study to evaluate and compare a new needle-free device developed for growth hormone delivery. Children answered descriptive questions related to nervousness and worry, hurt or pain, redness or bleeding, and stinging and wetness. Choices for answers for each of these five questions were none, a little, or a lot. None or a little was also combined to give a minimal category. Children also answered four questions that compared the needle-free device to their morning insulin needle injection in reference to ease of use, pain, nervousness, and overall preference. Half the children had single comfort rings inserted to increase the injection pressure. Results indicated no difference in question responses with or without pressure rings. Pain (92%), erythema (96%), worry (90%), stinging (86%) and wetness (96%) were minimal and significant (0.001 > p < 0.03) following all questions. Results of the comparative questionnaire indicated that the device was easier (p < 0.03) to use than needles and significantly preferred (p < 0.001) in 74% of children under age 10.

Anxiety↗

PubMed2001

Screening programs to identify children at risk for diabetes mellitus: psychological impact on children and parents.

Screening programs to identify persons atrisk for diabetes mellitus (DM), before disease onset, are considered essential to understanding the natural history of the disease and for prevention program development. However, screening programs are complicated by imprecise markers of disease risk, the absence of a known effective prevention method, the use of children, and a wide variety of psychological, social, and educational challenges. Research relevant to four issues is presented: (1) parent and child anxiety in response to at-risk notification as well as how participants cope with this news; (2) accuracy of mothers' understanding of their babies' risk status; (3) predictors of participant recruitment and retention in longitudinal studies of this type; and (4) protocol compliance in prevention trials for type 1 DM. Integration of behavioral research into screening and prevention trials would help address the ethical concerns raised by such trials and improve their scientific quality.

Anxiety↗

PubMed2001

Early life stress and disease among offspring and siblings of individuals with type 1 diabetes mellitus.

Major life events, recent life stressors, and childhood diseases were examined among children and adolescents who were offspring, siblings, or other relatives of persons with type 1 diabetes mellitus (DM). All youth were recruited as part of a multi-site nationwide trial on the prevention of type 1 DM; parents of 347 children (4 to 18 yr) completed measures that asked about children's life events, recent stressors, and childhood illnesses. Analyses compared age groups (young child, preadolescent, adolescent) and relative type (offspring, sibling, other relative). Findings revealed offspring and siblings did not differ from "other relatives" in terms of life events, recent life stress, and disease/illness variables. However, siblings were reported to have fewer major life events and fewer life stressors in the past 12 months than offspring; siblings also had fewer infectious diseases during the first two years of life compared to offspring. Few age-related differences were found. Overall, results suggest that offspring and siblings of persons with type 1 DM are not at a disadvantage in terms of early life stress or disease in comparison to youth who have other family members with diabetes. However, siblings may have some advantages relative to children who are offspring. The mechanisms underlying these relationships require further elucidation and study.

Aging↗

PubMed2001

Thymoma: update for the new millennium.

Thymomas are relatively common tumors of the anterior superior mediastinum. They are usually relatively slowly growing tumors and their prognosis depends on the macroscopic and microscopic invasion of surrounding tissues. Surgery is the mainstay treatment of thymomas, and complete resection represents one of the most important prognostic factors in this disease. Other important prognostic indicators include the tumor stage and size and the presence of symptoms. Postoperative radiotherapy is indicated in tumors with invasion of surrounding tissues, even if resection was radical, since it improves local control and survival. Cytotoxic chemotherapy has been employed in several relatively small phase II studies and in advanced disease has been demonstrated to produce a 50%-80% objective response rate. Neoadjuvant cytotoxic chemotherapy and/or external beam radiotherapy has been used with some success in patients with tumors which are not readily resectable. Novel antiproliferative systemic agents, with both cytotoxic and cytostatic mechanisms of action, are being tested in ongoing prospective clinical trials.

Humans↗

PubMed2001

Disordered eating, body mass, and glycemic control in adolescents with type 1 diabetes.

OBJECTIVE: To examine the relationship between disordered eating attitudes and behaviors, BMI, and glycemic control in adolescents with type 1 diabetes. RESEARCH DESIGN AND METHODS: In a cross-sectional design, 152 adolescents (ages 11-19 years) completed three scales from the Eating Disorders Inventory (EDI): Body Dissatisfaction, Drive for Thinness, and Bulimia. All subjects had diabetes for > 1 year. Glycemic control was assessed by glycosylated hemoglobin (HbA1c). Height and weight were measured to assess BMI. RESULTS: Adolescents with type 1 diabetes did not report more disordered eating attitudes and behaviors than the normative comparison sample. Male subjects with type 1 diabetes reported fewer symptoms of bulimia and female subjects with type 1 diabetes reported greater body satisfaction than the normative group. A higher BMI was a significant predictor of greater body dissatisfaction, more so for female than male subjects. Symptoms of bulimia were associated with older adolescence and female sex. Those with more symptoms of bulimia were also more likely to have a higher BMI. Sex (female) and body dissatisfaction (more dissatisfied) predicted a stronger desire to be thin. Longer duration of disease, more symptoms of bulimia, and obesity all predicted poorer glycemic control. CONCLUSIONS: Female patients aged 13-14 years seem to be at greatest risk for developing disordered eating patterns. Using the clinical cutoff score (> or = 5) of the EDI Bulimia subscale as a screener in diabetes clinics may help identify adolescents whose disordered eating patterns are likely to compromise their glycemic control.

Adolescent↗

PubMed2001

Comparing syntactic complexity in medical and non-medical corpora.

With the growing use of Natural Language Processing (NLP) techniques as solutions in Medical Informatics, the need to quickly and efficiently create the knowledge structures used by these systems has grown concurrently. Automatic discovery of a lexicon for use by an NLP system through machine learning will require information about the syntax of medical language. Understanding the syntactic differences between medical and non-medical corpora may allow more efficient acquisition of a lexicon. Three experiments designed to quantify the syntactic differences in medical and non-medical corpora were conducted. The results show that the syntax of medical language shows less variation than non-medical language and is likely simpler. The differences were great enough to question the applicability of general language tools on medical language. These differences may reduce the difficulty of some free text machine learning problems by capitalizing on the simpler nature of narrative medical syntax.

Artificial Intelligence↗

PubMed2001

Using narrative reports to support a digital library.

The vast amount of information collected and stored in clinical systems can be a significant challenge in the integration of digital libraries and electronic medical records, especially the selection of clinical data to be used in the search, retrieval, and summarization processes. In this study, we describe the use of information retrieval measures with natural language processor output to identify critical information in narrative reports. Our hypothesis is that clinical data that occur often in narrative reports are less important to clinicians than findings that occur rarely. We used the information retrieval methods to analyze one year of discharge summaries. We then conducted a performance study, using physicians as subject. Results show that the methods can be used for filtering critical information from reports. Further studies need to be done on evaluation of the method based on an evaluation of the system performance in the context of a digital library.

Humans↗

PubMed2000

Exploring the clinical pharmacist's role in improving home care for patients with diabetes.

Diabetes is a common condition among clients receiving home care services. Improved glycemic control can greatly thwart the long-term complications of diabetes. A study examining the role of a clinical pharmacist was performed in a home care agency in which 105 clients were interviewed and their respective charts reviewed with the following results: 37% were incorrectly classified as to type of diabetes, serum creatinine and HbA1c values were not commonly recorded, and clients tended to have complex drug regimens with a large number of potential drug-related problems. The clinical pharmacist's potential impact in this environment is great based on the data gathered from this study.

Adult↗

PubMed2000

Population pharmacokinetics of aminoglycosides in critically ill trauma patients on once-daily regimens.

BACKGROUND: Once-daily dosing regimens of aminoglycosides are routinely used in critically ill trauma patients. However, the pharmacokinetic parameters are variable in these patients. The purpose of this study was to evaluate the pharmacokinetics of aminoglycosides in critically ill trauma patients receiving once-daily dosing regimens. METHODS: At least two aminoglycoside concentrations were measured in each patient. Population pharmacokinetic parameters were estimated on the basis of a one-compartment structural model and the program nonlinear mixed effects modeling. RESULTS: Fifty-three aminoglycoside concentrations from 19 patients were analyzed. The aminoglycoside clearance was 5.47 L/h. The mean volume of distribution was 22.2 L (0.3 L/kg). The mean half-life was 2.9 hours. Serum-aminoglycoside concentrations were undetectable for longer than 12 hours in 4 of 19 patients. Weight, age, or serum creatinine did not significantly explain the variability. CONCLUSION: There is marked variability in aminoglycoside pharmacokinetic parameters in critically ill trauma patients. This may lead to prolonged drug-free intervals. Individualized dosing of critically ill trauma patients on the basis of at least two serum-aminoglycoside concentrations seems indicated when using once-daily dosing regimens.

Adolescent↗

PubMed2000

Blood glucose monitoring skills in children with Type I diabetes.

While blood glucose monitoring has become increasingly important in diabetes care, studies have yet to address the accuracy of youngsters' performance of blood glucose testing with current reflectance meters. The present study examined testing skills and predictors of accurate testing skills in a sample of 7-14-year-old children attending a summer camp for youth with diabetes (n=266). A 15-item behavior observational skill test was used to assess accuracy of blood glucose monitoring skills with reflectance meters. Accurate performance of individual skills ranged between 14.6% and 99.6% for the sample. However, a number of children made critical errors (errors that were likely to lead to inaccurate blood glucose testing results). When duration of diabetes and metabolic control were controlled, female gender, older age, experience with a particular meter, and absence of hypoglycemia at the time of testing were positively associated with accurate skill performance. Findings suggest that younger children, children using a new blood glucose testing meter, and children suspected of having hypoglycemia should be supervised and observed when testing. Although all young children should be supervised when blood glucose testing, boys may need closer supervision until an older age than girls. This study underscores the need for health care providers to periodically observe children's blood glucose monitoring techniques to assure accurate testing habits and to correct problematic testing behaviors.

Adolescent↗