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Biomedical subjects

C C Johnson

Publications and source records attributed to C C Johnson.

At least 73 records · Page 4Linked to original sources
PubMed1996

Alzheimer's disease and apolipoprotein E-4 allele in an Amish population.

Alzheimer's Disease (AD) is a complex genetic disorder with four loci already identified. Mutations in three of these, the amyloid precursor protein, presenilin I, and presenilin II, cause early-onset AD. The apolipoprotein E (APOE) gene contributes primarily to late-onset AD. The APOE-4 allele acts in a dose-related fashion to increase risk and decrease the age-of-onset distribution in AD. We examined the effect of APOE on AD in a previously unstudied Amish population that has a lower prevalence of dementia compared with other populations. We sampled a large inbred family with 6 late-onset AD members. We also genotyped 53 individuals from the general Amish population as controls for the APOE allele frequency estimates. The frequency of the APOE-4 allele in the Amish controls was 0.037 +/- 0.02. This differed significantly compared with three independent sets of non-Amish white controls (p < 2 x 10(-4), p < 6 x 10(-5), and p < 2 x 10(-6)). In addition, all Amish AD-affected individuals had APOE 3/3 genotypes; no APOE X/4 or 4/4 individuals were observed. We suggest that the lower frequency of dementia in the Amish may be partially explained by the decreased frequency of the APOE-4 allele in this population, and that the inbred nature of this pedigree, with its strong clustering of cases contrasted against the lower frequency of dementia, indicates that additional genetic factors influence late-onset AD.

Adult↗
PubMed1996

The prevalence of anti-latex IgE antibodies among registered nurses.

BACKGROUND: Recent studies have reported that the prevalence of latex allergy among volunteer populations of health care workers ranges from 2% to 25%. To date, no epidemiologic study has investigated the prevalence of latex allergy and its relationship to possible risk factors among nurses. METHODS: Registered nurses (n = 741) in a large metropolitan hospital participated in a latex allergy prevalence study. Latex exposure data were obtained through self-administered questionnaires. Blood samples were classified as positive or negative for anti-latex IgE antibodies. Associations between potential risk factors for latex allergy and anti-latex antibodies were assessed. RESULTS: The participation rate was 90.6% among eligible nurses. Sixty-five samples were positive for a prevalence of 8.9% (95% confidence interval, 6.7 to 10.8). No differences in latex positivity among five nursing specialties were noted. Logistic regression indicated that after adjusting for age and sex, the following factors were significantly associated with latex seropositivity: nonwhite race (odds ratio [OR] = 4.2), reported histories of penicillin allergy (OR = 2.2), pruritic skin (OR = 2.2), conjunctivitis (OR = 3.0), localized urticaria (OR = 1.8), hay fever (OR = 2.1), avocado allergy (OR = 9.9), and ragweed allergy (OR = 3.4). CONCLUSIONS: The prevalence of latex sensitization appeared to be substantial (8.9%) among the nurses studied, and the prevalence did not vary by nursing specialty. The factors associated with latex positivity in the logistic regression model correctly classified 81.3% of the nurses with a sensitivity and specificity of 66.7% and 82.7%, respectively.

Adult↗
PubMed1996

Working with noncompliant and abusive dialysis patients: practical strategies based on ethics and the law.

The patient population in dialysis facilities today reflects common societal problems such as human immunodeficiency virus infection, illicit drug use, distrust of and disrespect for authority, and a propensity toward violence. An increase in calls from dialysis units for guidance in dealing with noncompliant and abusive patients prompted ESRD Network 5 to examine this problem and develop an educational program, "Working with Noncompliant and Abusive Patients." This article provides an overview of the ESRD Network 5 study of the ethical, legal, psychosocial, and administrative aspects of this problem, presents practical strategies for working with such patients, and demonstrates the application of these strategies in three cases. It emphasizes the importance for dialysis units of four elements in the successful treatment of such patients: instruction for all levels of dialysis staff; a team approach; written policies; and patient education at the time of admission about these policies, including the consequences of verbal and physical abuse and the circumstances under which patients will be discharged from the dialysis unit.

Aggression↗
PubMed1996

Incidence and prevalence of physician-diagnosed asthma in a suburban population of young adults.

BACKGROUND: Asthma is a common chronic disease of both children and adults, but there have been few reports of the incidence of asthma in well defined adult populations. OBJECTIVE: To determine the incidence and prevalence of asthma in a population of young adults living in suburban Detroit. METHODS: As part of a study of the development of allergic disease in children, the parents of 841 study children, from a defined, well characterized population, were questioned about their personal histories of allergic disease, including asthma, during the mother's pregnancy. The children have been followed from birth until 4 years of age. When the child became 4, the parents were again questioned about allergic disease. Those reporting asthma when the child was 4 but not prior to the child's birth, were recontacted to confirm that they had been diagnosed by a physician as having asthma in the 4-year interval. Because of prior reports concerning racial differences in the prevalence of asthma and the small number of non-white mothers in the study population, calculations of asthma prevalence and incidence were limited to the 760 mothers, who described themselves and their baby's father as white. RESULTS: The parents studied were young adults mean age 28.7 [(standard deviation (SD) 4.5 years] and 31.0 (SD 5.0) years, of mothers and fathers, respectively. These parents were relatively well educated with 30.7% of mothers and 43.5% of fathers having college degrees. The initial prevalence of a previous physician diagnosis of asthma was 7.5% [95% confidence interval (95% CI) = 5.7-9.6] in the mothers and 6.9% (95% CI = 5.2-9.0) in the fathers, yielding a total prevalence of 7.2% (95% CI = 5.9-8.7) in these 1484 adults. Five hundred thirty-three mothers and 498 fathers (total = 1031), who did not report asthma during the mothers' pregnancies, were available for questioning when the children were 4 years old. The average yearly incidence of asthma was 5.2 (95% CI = 2.6-9.2) per 1000 in the mothers and 1.5 (95% CI = 0.3-4.4) per 1000 in the fathers (P = .058), with an overall incidence of 3.4 (95% CI = 1.8-5.7) per 1000. The average yearly incidence was 5.3/1000 in those < 30 years old and 1.5/1000 in those > or = 30 years of age (P = .056). CONCLUSIONS: We conclude that the incidence of asthma in this population of relatively young, well educated, white adults is approximately 3.4 per 1000 per year and that newly diagnosed asthma was more common in women and in those < 30 years of age.

Adolescent↗
PubMed1996

Acute hemodynamic and neurohoromonal effects of furosemide in critically ill pediatrics patients.

OBJECTIVES: To study the acute hemodynamic effects of furosemide in critically ill pediatrics patients, the temporal relationship between hemodynamic changes and changes in neuroendocrine axis, and the temporal relationship between hemodynamic changes and urine output. DESIGN: Prospective study. SETTING: Pediatric intensive care unit in a tertiary care university center. PATIENTS: Fourteen critically ill pediatric patients who clinically required diuretic therapy. INTERVENTIONS: Before and after furosemide administration, hemodynamic and neurohormonal measurements were taken. MEASUREMENTS AND MAIN RESULTS: Hemodynamic and neurohormonal responses to acute diuretic therapy were measured in 14 pediatric patients treated with furosemide (1 mg/kg/dose). Cardiac index deteriorated by 10 mins after drug administration (-9.4+/-3.9%, p<.05) and was associated with an increase in systemic vascular resistance (17.1+/-4.8%, p<.05). There was a subsequent increase in cardiac index (20+/-4.9%, p<.05) at 30 mins, with a decrease in systemic vascular resistance (-11.5+/-5.2%, p<.05). These hemodynamic changes were associated with marked increases in renin and norepinephrine concentrations and an increase in urinary prostaglandin release. The hemodynamic and neurohormonal effects had their onset before maximum diuresis. CONCLUSION: Intravenous furosemide administration in acutely ill pediatric patients results in an acute but transient deterioration in cardiac function that appears to parallel the neuroendocrine changes rather than the acute diuresis.

Adolescent↗
PubMed1996

A portable nitric oxide scavenging system designed for use on neonatal transport.

OBJECTIVE: To evaluate a portable scavenging system for nitric oxide and its oxides, designed for use on neonatal transport. DESIGN: A prospective evaluation of the nitric oxide scavenging system, using a neonatal transport incubator ventilator and a test lung. SETTING: Laboratory of a tertiary care children's hospital. INTERVENTIONS: The scavenging system was tested, using a neonatal transport incubator with attached ventilator, ventilator circuit, and a neonatal test lung. Nitric oxide was administered on the inspiratory limb, and nitric oxide and its oxides were measured in the expiratory gas after passing through the scavenger. MEASUREMENTS AND MAIN RESULTS: A modified scrubber assembly was filled with 50% activated charcoal and 50% aluminas potassium permanganate pellets (3). Three wire meshes were placed before, in between, and after the two chemicals to facilitate gas flow. Using the maximum FIO2, with a nitric oxide concentration of 120 parts per million (ppm), the test lung continuous flow ventilation (FIO2 of 0.86, peak inspiratory pressure of 30 cm H2O, positive end-expiratory pressure of 6 cm H2O) and respiratory rate of 60 breaths/min) was performed for 4 hrs with each of four freshly prepared scavenging systems. A fifth scavenging system was tested for a 12-hr period. The mean composition of the exhaled gases for 4 hrs were: nitric oxide 0.01 +/- 0.03 (SD) ppm, nitric dioxide 0.06 +/- 0.06 ppm, and other oxides 0.05 +/- 0.09 ppm. After 12 hrs of 120 ppm of inhaled nitric oxide, the fifth scavenger system had undetectable nitric oxide, nitric dioxide, and other oxides in the exhaled gas. Normal room air contained between 0.0 and 0.03 ppm of nitric oxide, 0.0 and 0.02 ppm of nitric dioxide, and 0.0 and 0.02 ppm of other oxides. CONCLUSION: Nitric oxide, nitric dioxide, and other dioxides can be safely scavenged by this portable scavenging system, allowing safe administration of nitric oxide free from environmental contamination with nitric oxide and its oxides.

Critical Care↗
PubMed1996

Effectiveness of a physician education program in reducing consumption of hospital resources in elective total hip replacement.

A physician education program altered the consumption of hospital resources by orthopedic surgeons doing total hip replacement. They were presented with verbal and written physician-specific materials during a 7-week period. Xbar and R charts were used to display measurements of resource consumption before and after the educational program. Physicians were provided with surgeon-specific data profiling their own practice and that of their peers. Inferential statistics were used to validate the effects of education. Length of hospital stay for patients receiving total hip replacement dropped from 13.7 days to 9.9 days. Adjusted total charges dropped from $22,103 to $18,607. The variance for length of stay and total charges dropped by one half or more. Physician education programs are effective in reducing consumption of hospital resources. Statistical process control data formatting appears to make the data more usable to these physicians.

Education, Medical, Continuing↗
PubMed1996

Evaluation of IgA measurements as a method for detecting maternal blood contamination of cord blood samples.

Several studies have evaluated the value of cord blood IgE concentrations for predicting the risk of allergic disease in children. In all of these studies it is necessary to exclude cord blood samples in which the IgE may be falsely elevated due to admixing of maternal and fetal blood during parturition. The most common method for detecting mixing of fetal and maternal blood is measurement of cord blood IgA concentrations. We have examined the theoretical basis of IgA measurements for detecting maternal blood contamination and reexamined our own data to evaluate IgA measurements. Our data suggest that the average IgA concentration of 28.2 micrograms/ml used in previous studies may not adequately exclude contaminated cord blood sample. Failure to reject contaminated cord blood samples would reduce the positive predictive value of cord blood IgE measurements.

Blood Grouping and Crossmatching↗
PubMed1996

Gastrointestinal tract colonization with vancomycin-resistant Enterococcus faecium in an animal model.

Vancomycin-resistant enterococci have become important nosocomial pathogens in many institutions. The gastrointestinal tract of susceptible hosts serves as the likely reservoir from which the organism is disseminated. To study factors promoting colonization and the efficacy of decontamination therapy with antimicrobial agents, a model of gastrointestinal colonization with vancomycin-resistant Enterococcus faecium was developed in CF1 mice. At baseline, all animals were colonized with non-vancomycin-resistant enterococci (5.0 log10 CFU/g), but vancomycin-resistant organisms were not detectable. Following gastric inoculation with 5 x 10(8) CFU of a clinical isolate of vancomycin-resistant E. faecium, the strain transiently colonized the gastrointestinal tract of 100% of mice but was undetectable by Day 14 (< or = 2.7 log10 mean CFU/g). In animals who received 5 mg of streptomycin per ml or 250 micrograms of vancomycin per ml in drinking water, colonization with the organism occurred at significantly higher bacterial counts than in controls at 7 days following inoculation (9.4 for vancomycin, 9.2 for streptomycin, and 5.1 log10 mean CFU/g for controls; P < 0.05). Fecal concentrations of vancomycin-resistant E. faecium persisted at high counts through Day 22 in mice receiving these antibiotics, but low counts were also still detected in 3 of 10 control animals. In mice with previously established vancomycin-resistant E. faecium colonization, oral administration of ramoplanin, a lipoglycodepsipeptide to which the strain was susceptible, suppressed growth of all enterococci in feces, including the vancomycin-resistant strain after 7 days of therapy (< or = 3.1 and < or = 3.3 log10 mean CFU/g for vancomycin and streptomycin groups, respectively). All mice had a recurrence of colonization with vancomycin-resistant E. faecium after the ramoplanin was discontinued. In summary, this animal model demonstrates the importance of antibiotics in predisposing to gastrointestinal colonization with vancomycin-resistant Enterococcus spp. Although treatment with ramoplanin temporarily suppressed the organism, recurrence of colonization due to relapse or reinfection occurred.

Administration, Oral↗
PubMed1996

Using process data to explain outcomes. An illustration from the Child and Adolescent Trial for Cardiovascular Health (CATCH).

The purpose of this article is to illustrate the use of process evaluation for understanding study outcomes. Data from the Child and Adolescent Trial for Cardiovascular Health (CATCH), a large school-based field trial, are used. Teacher characteristics, measures of classroom curriculum implementation, and competing influences are linked to changes in dietary knowledge, intentions, and self-efficacy of students in the intervention schools. Multiple regression analyses indicate that teacher characteristics did not predict program implementation. Teacher characteristics and program fidelity, or the number of modifications made to the classroom curriculum during implementation, had direct and independent effects on student outcomes.

Adolescent↗
PubMed1996

Parental history of atopic disease and concentration of cord blood IgE.

BACKGROUND: A family history of atopy, and cord blood immunoglobulin E concentration, have been shown to be predictors of atopic disease in children. Several studies have suggested that parental atopy may be related to newborn immunoglobulin E. OBJECTIVE: The purpose of our analysis was to evaluate whether parental history of allergic disease was associated with cord blood immunoglobulin E concentration. METHODS: The study subjects were from a defined population of 777 newborns delivered between 1987 and 1989. The mothers of these children completed a questionnaire during pregnancy concerning themselves and the child's father, including parental history of physician diagnosis of allergic diseases (allergies, hay fever and asthma). Total immunoglobulin E levels were quantitated in cord blood samples with an enzyme-linked immunoassay. RESULTS: Median cord blood immunoglobulin E concentration was higher among infants whose mothers had a history of atopic disease, particularly for those with a history of asthma (P < 0.022) and allergen immunotherapy (P < 0.016) vs infants whose mothers had no history of any atopic disease. Comparing all babies with a maternal history of asthma, to babies where neither parent had a history of any atopic disease, the median cord blood immunoglobulin E was significantly higher (0.36 IU/mL vs 0.21 IU/mL; P < 0.009). This association was found only among female infants (0.49 IU/mL vs 0.20 IU/mL; P < 0.001). CONCLUSION: Maternal, but not paternal, history of atopic disease was associated with an elevated immunoglobulin E among newborns. For maternal asthma, this association was only evident in infant girls.

Enzyme-Linked Immunosorbent Assay↗
PubMed1995

Calcaneal ultrasonic measurements discriminate hip fracture independently of bone mass.

We studied 336 elderly white women, of whom 22 had previously suffered a hip fracture and 22 had previously suffered a vertebral fracture. All subjects were 60 years old or older with a mean age of 73:7 years. Measurements of ultrasonic transmission velocity (UTV), broad-band ultrasonic attenuation (BUA) and stiffness (STF) were made at the os calcis using a Lunar Achilles ultrasound device. Measurements of lumbar spine bone mineral density (L2-4 BMD) and femoral neck BMD were made using dual-energy X-ray absorptiometry. The fracture groups were significantly older and had more years since menopause than the control groups. Logistic regression showed that measurements of UTV, STF and BUA discriminated between fracture and non-fracture subjects for both the hip (p < 0.001) and spine (p < 0.05). Femoral neck BMD discriminated both hip and vertebral fractures from controls (p < 0.001 and p < 0.01, respectively). Spinal BMD discriminated between subjects with vertebral fractures and those without (p < 0.01), but not hip fractures (p = 0.64). For hip fracture, areas under receiver-operating characteristic (ROC) curves were 0.85 for UTV, 0.83 for STF, 0.79 for BUA, 0.78 for femoral neck BMD and 0.53 for spinal BMD. For vertebral fracture, areas under the ROC curve were 0.68 for UTV, 0.70 for STF, 0.66 for BUA, 0.66 for femoral neck BMD and 0.67 for spinal BMD.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1995

In vitro activity of RP 59500 (quinupristin/dalfopristin) against antibiotic-resistant strains of Streptococcus pneumoniae and enterococci.

The activity of RP 59500 (quinupristin/dalfopristin) was evaluated in vitro against antibiotic-resistant strains of Streptococcus pneumoniae (N = 15) and Enterococcus spp. (N = 43). By broth dilution MIC tests RP 59500 was highly active against penicillin-resistant S. pneumoniae and vancomycin-resistant Enterococcus faecium, but showed poor activity against E. faecalis. In time-kill studies the drug was rapidly bactericidal against S. pneumoniae but failed to kill most enterococci, even in the presence of gentamicin or human serum.

Drug Resistance, Microbial↗
PubMed1995

Activity of cefepime against ceftazidime-resistant gram-negative bacilli using low and high inocula.

Cefepime is a broad-spectrum cephalosporin that is reported to have enhanced activity against ceftazidime-resistant Gram-negative bacilli. In this study the effects of varying inoculum size on in-vitro susceptibility to cefepime and other selected antimicrobial agents were determined by agar dilution MICs and in time-kill studies. Among strains of Pseudomonas aeruginosa (n = 55) and Enterobacter spp (n = 56) that had previously been identified as ceftazidime-resistant, 73% and 96% were susceptible to cefepime (MIC < or = 16 mg/L), respectively, when tested with an inoculum of 10(4) cfu. However, with an inoculum of 10(7) cfu, 98% and 100% of strains were resistant, respectively. Furthermore, the bactericidal activity of cefepime against ceftazidime-resistant isolates was also inoculum-dependent. In time-kill studies, bactericidal action was obtained only at the lowest concentration of organisms (10(4) cfu/mL). beta-Lactamase extracted from an isolate of P. aeruginosa that demonstrated an inoculum effect had a lower affinity for cefepime than for ceftazidime. Overall, cefepime proved to be more resistant to hydrolysis by the beta-lactamase. However, differences in kinetics of the beta-lactamase against cefepime or ceftazidime do not appear to be of consequence in determining susceptibility of P. aeruginosa and Enterobacter spp. at high bacterial densities, since most strains with chromosomally-mediated beta-lactamase are highly resistant.

Cefepime↗
PubMed1995

Health ahead--the Heart Smart Family approach to prevention of cardiovascular disease.

The Heart Smart Family Health Promotion program is a unique approach to education and skills development aimed at improving the cardiovascular health of entire families. By including the entire family system, rather than singling out one individual for behavior change, social support and self-confidence are enhanced and the probability for maintenance of behavioral skills is increased. The Family Health Promotion program uses a format that minimizes lecture and maximizes awareness, skills development, problem-solving, and real-life application over a 12- to 16-week agenda. Behavioral counseling and contingency contracting provide opportunities for the practice and reinforcement of new behaviors. Initial evaluations of the program model developed with cardiovascular high-risk children and their parents indicated that parents significantly increased health knowledge, lowered blood pressure, became more physically active, and decreased their intake of total fat, saturated fat, and sodium. A clinically significant reduction in children's blood pressure also was observed. Children's weight (adjusted for height) remained stable. The Family Health Promotion program resulted in positive changes in cardiovascular risk factors and can be adapted to any clinical or health-promotion setting.

Cardiovascular Diseases↗
PubMed1995

Measurement of self-efficacy for diet-related behaviors among elementary school children.

Health promotion interventions intended to improve dietary behavior frequently incorporate self-efficacy as a construct to enhance behavior change. This paper presents results from a study to establish psychometric properties of a scale to measure children's self-efficacy for selecting healthful food. As part of a series of pilot studies to develop instrumentation for the Child and Adolescent Trial for Cardiovascular Health (CATCH), data were collected on third and fourth grade students (n = 1,127). Data analyses were conducted to estimate internal consistency, test-retest reliability, factorial validity, and criterion related validity. Results revealed acceptable estimates of internal consistency for the dietary self-efficacy scale (coefficient alpha = .84). Self-efficacy was strong associated with the children's usual food choices, accounting for about 34% of variance (Multiple R = .58). Findings support using such an instrument for evaluating intervention programs addressing nutrition behavior and for studies to determine the association of self-efficacy to dietary behavior or related constructs.

Child↗