Biomedical subjects

J C Johnson

Publications and source records attributed to J C Johnson.

At least 37 records · Page 2Linked to original sources

PubMed2000

Quantification of measurement of femoral head coverage and Norberg angle within and among four breeds of dogs.

OBJECTIVE: To report values for percentage coverage of the femoral head (PC) and Norberg angle (NA) in 4 common breeds of dogs and to determine values for each that distinguish between normal and dysplastic hip status on the basis of Orthopedic Foundation for Animals (OFA) hip evaluation. ANIMALS: 1,841 dogs 24 to 48 months of age that were Labrador Retrievers (455), Golden Retrievers (423), Rottweilers (545), or German Shepherd Dogs (418). PROCEDURE: Retrospective analysis of NA and PC measured from standard OFA ventrodorsal pelvic radiographs from 4 breeds of dog. RESULTS: Norberg angle ranged from 67.4 to 124.4 degrees for Labrador Retrievers, 59.7 to 128.6 degrees for Rottweilers, 70.2 to 119.4 degrees for Golden Retrievers, and 55.3 to 121.3 degrees for German Shepherd Dogs. The PC ranged from 6.5 to 79.9% for Labrador Retrievers, 5.7 to 79.5% for Rottweilers, 8.3 to 79.3% for Golden Retrievers, and 5.4 to 83.7% for German Shepherd Dogs. On the basis of logistic regression modeling for determining normal versus abnormal hip status for all 4 breeds, cutoff points for NA were <105 degrees and PC were <50%. CONCLUSIONS AND CLINICAL RELEVANCE: Results of our study indicate that cutoff points of NA of 105 degrees and PC of 50% do not differentiate normal versus dysplastic hip status. Each of the 4 breeds had different values for NA and PC that distinguished normal from dysplastic hip status.

Animals↗

PubMed2000

Predictors of behavior and performance in extreme environments: the Antarctic space analogue program.

BACKGROUND: To determine which, if any, characteristics should be incorporated into a select-in approach to screening personnel for long-duration spaceflight, we examined the influence of crewmember social/ demographic characteristics, personality traits, interpersonal needs, and characteristics of station physical environments on performance measures in 657 American men who spent an austral winter in Antarctica between 1963 and 1974. METHODS: During screening, subjects completed a Personal History Questionnaire which obtained information on social and demographic characteristics, the Deep Freeze Opinion Survey which assessed 5 different personality traits, and the Fundamental Interpersonal Relations Orientation-Behavior (FIRO-B) Scale which measured 6 dimensions of interpersonal needs. Station environment included measures of crew size and severity of physical environment. Performance was assessed on the basis of combined peer-supervisor evaluations of overall performance, peer nominations of fellow crew-members who made ideal winter-over candidates, and self-reported depressive symptoms. RESULTS: Social/demographic characteristics, personality traits, interpersonal needs, and characteristics of station environments collectively accounted for 9-17% of the variance in performance measures. The following characteristics were significant independent predictors of more than one performance measure: military service, low levels of neuroticism, extraversion and conscientiousness, and a low desire for affection from others. CONCLUSIONS: These results represent an important first step in the development of select-in criteria for personnel on long-duration missions in space and other extreme environments. These criteria must take into consideration the characteristics of the environment and the limitations they place on meeting needs for interpersonal relations and task performance, as well as the characteristics of the individuals and groups who live and work in these environments.

Adult↗

PubMed2000

Behavior and performance on long-duration spaceflights: evidence from analogue environments.

BACKGROUND: Analyses of data collected in Antarctica since 1963 were conducted to identify features of behavior and performance likely to occur during long-duration missions in space. METHODS: The influence of mission duration and station latitude on POMS mood scores was examined in 450 American men and women who wintered-over in Antarctica between 1991 and 1998. The influence of crewmember social characteristics, personality traits, interpersonal needs, and station environments on measures of behavior and performance at the end of the austral winter was examined in 657 American men who wintered-over between 1963 and 1974. Both data sets were used to examine the influence of crew social structure on individual performance. RESULTS: Seasonal variations in mood appear to be associated with the altered diurnal cycle and psychological segmentation of the mission. Concurrent measures of personality, interpersonal needs, and coping styles are better predictors of depressed mood and peer-supervisor performance evaluations than baseline measures because of the unique features of the station social and physical environments and the absence of resources typically used to cope with stress elsewhere. Individuals in crews with a clique structure report significantly more depression, anxiety, anger, fatigue and confusion than individuals in crews with a core-periphery structure. Depressed mood is inversely associated with severity of station physical environment, supporting the existence of a positive or "salutogenic" effect for individuals seeking challenging experiences in extreme environments. CONCLUSION: Behavior and performance on long-duration spaceflights is likely to be seasonal or cyclical, situational, social, and salutogenic.

Adaptation, Psychological↗

PubMed2000

Preliminary report on a method of human papillomavirus DNA extraction from verruca plantaris for polymerase chain reaction studies.

This preliminary report on the Chelex-based extraction method of HPV DNA from verruca plantaris is the first step in a series of studies on verruca plantaris undertaken, jointly, by the Departments of Podiatric Medicine and Microbiology at Des Moines University-Osteopathic Medical Center, Des Moines, Iowa. Current projects include the development of new primers for PCR studies of HPV, exploration of different viral DNA extraction methods, and surveys concerning treatment, success of therapies, and the epidemiology of verruca plantaris.

DNA, Viral↗

PubMed2000

Stress management in rheumatoid arthritis: what is the underlying mechanism?

OBJECTIVE: To test whether change in cognitive-behavioral variables (such as self-efficacy, coping strategies, and helplessness) is a mediator in the relation between cognitive behavior therapy and reduced pain and depression in persons with rheumatoid arthritis (RA). METHODS: A sample of patients with RA who completed a stress management training program (n = 47) was compared to a standard care control group (n = 45). A path analysis testing a model including direct effects of comprehensive stress management training on pain and depression and indirect effects via change in cognitive-behavioral variables was conducted. RESULTS: The path coefficients for the indirect effects of stress management training on pain and depression via change in cognitive-behavioral variables were statistically significant, whereas the path coefficients for the direct effects were found not to be statistically significant. CONCLUSION: Decreases in pain and depression following stress management training are due to beneficial changes in the arenas of self-efficacy (the belief that one can perform a specific behavior or task in the future), coping strategies (an individual's confidence in his or her ability to manage pain), and helplessness (perceptions of control regarding arthritis). There is little evidence of additional direct effects of stress management training on pain and depression.

Adaptation, Psychological↗

PubMed1999

Elevated immunoglobulin E (IgE) levels in children with exposure to environmental lead.

Lead has been reported to be an immunosuppressive agent in animal systems at levels far below those recognized as overtly toxic. Little data exist on lead's effects on the human immune system, especially in young children who are at greatest risk for exposure to this environmental hazard. The effects of environmental lead exposure on the human immune system were examined in a population of young children, age 9 months-6 years, from the urban population of Springfield-Greene County, Missouri. Reported here are data from 279 children with blood lead levels ranging from 1 to 45 microg/dl. White blood cell populations have been enumerated and examined for cell surface expression of activation markers. Serum has been analyzed for IgE, specific titers to Rubella vaccine, sCD25 (the soluble form of the IL2 receptor), sCD27 (the soluble form of the lymphocyte specific member of the tumor necrosis factor receptor family), and IL4 (the cytokine interleukin 4). Variation of these assays with age of the child was considered in statistical analysis of data. A statistically significant relationship of IgE and blood lead level was found in this population; as blood lead (PbB) level increases, IgE level increases. No other statistically significant differences between risk categories or other associations with blood lead level were found. The exact mechanism for this apparent stimulus of IgE-producing B cells remains to be elucidated. The development of allergic symptoms is often preceded by an increase in IgE. These data indicate that ingested lead could play a role in this process by stimulating IgE production.

Age Factors↗

PubMed1999

Long-term outcome in mixed connective tissue disease: longitudinal clinical and serologic findings.

OBJECTIVE: To determine the long-term clinical and immunologic outcomes in a well-characterized cohort of 47 patients with mixed connective tissue disease (MCTD), including reactivity with U small nuclear RNP (snRNP) polypeptides. METHODS: Patients were followed up over a period of 3-29 years with immunogenetic and systematic clinical and serologic analysis. Sera were analyzed for reactivity with snRNP polypeptides U1-70 kd, A, C, B/B', and D, for anti-U1 RNA, and for anticardiolipin antibodies (aCL). RESULTS: The typical core clinical features of MCTD tended to develop over time; features of inflammation as well as Raynaud's phenomenon and esophageal hypomotility diminished, while pulmonary hypertension, pulmonary dysfunction, and central nervous system disease persisted, following treatment. A favorable outcome was observed in 62% of patients; 38% had continued active disease or had died, with death associated with pulmonary hypertension and aCL. All patients had autoantibodies to the U1-70 kd polypeptide of snRNP, and most were positive for anti-U1 RNA. An orderly progression of intramolecular spreading of autoantibody reactivity against snRNP polypeptides was observed, as was the novel finding of "epitope contraction" followed by disappearance of anti-snRNP autoantibodies during prolonged remission. CONCLUSION: These patients demonstrated the typical immunogenetic, clinical, and serologic findings of MCTD, and the condition rarely evolved into systemic lupus erythematosus or systemic sclerosis. The majority of patients had favorable outcomes, with pulmonary hypertension being the most frequent disease-associated cause of death. Intramolecular spreading of autoantibody reactivity against snRNP polypeptides was observed, followed by "epitope contraction" and ultimate disappearance of anti-snRNP autoantibodies during prolonged disease remission.

Autoantibodies↗

PubMed1999

A meta-analysis of fibromyalgia treatment interventions.

OBJECTIVE: To evaluate and compare the efficacy of pharmacological and nonpharmacological treatments of fibromyalgia syndrome (FMS). METHODS: This meta-analysis of 49 fibromyalgia treatment outcome studies assessed the efficacy of pharmacological and nonpharmacological treatment across four types of outcome measures-physical status, self-report of FMS symptoms, psychological status, and daily functioning. RESULTS: After controlling for study design, antidepressants resulted in improvements on physical status and self-report of FMS symptoms. All nonpharmacological treatments were associated with significant improvements in all four categories of outcome measures with the exception that physically-based treatment (primarily exercise) did not significantly improve daily functioning. When compared, nonpharmacological treatment appears to be more efficacious in improving self-report of FMS symptoms than pharmacological treatment alone. A similar trend was suggested for functional measures. CONCLUSION: The optimal intervention for FMS would include nonpharmacological treatments, specifically exercise and cognitive-behavioral therapy, in addition to appropriate medication management as needed for sleep and pain symptoms.

Activities of Daily Living↗

PubMed1999

The role of fructose-1,6-diphosphate in cell migration and proliferation in an in vitro xenograft blood vessel model of vascular wound healing.

Both smooth muscle cells and endothelial cells play an important role in vascular wound healing. To elucidate the role of fructose-1,6-diphosphate, cell proliferation and cell migration studies were performed with human endothelial cells and rat smooth muscle cells. To mimic blood vessels, endothelial and smooth muscle cells were used in 1:10, 1:5, and 1:1 concentrations, respectively, mimicking large-, mid-, and capillary-sized blood vessels. Cell migration was studied with fetal bovine serum-starved cells. For cell proliferation assay, cells were plated at 30-50% confluency and then starved. The cells were incubated for 48 h with fructose-1,6-diphosphate at (per ml) 10 mg, 1 mg, 500 microg, 250 microg, 100 microg, and 10 microg, pulsed with tritiated-thymidine and incubated with 1 N NaOH for 30 min at room temperature, harvested, and counted. For migration assay, confluent cells were starved, wounded, and incubated for 24 h with same concentrations of fructose-1,6-diphosphate as in proliferation assay. The cells were fixed and counted. Smooth muscle cell proliferation was inhibited by fructose-1,6-diphosphate at 10 mg/ml. In the xenograft models of 1:10, 1:5, and 1:1 fructose-1,6-diphosphate inhibited proliferation at 10 mg/ml. In migration studies 10 mg fructose-1,6-diphosphate per ml was inhibitory to both cell types. In large-, mid-, and capillary-sized blood vessels, fructose-1,6-diphosphate inhibited proliferation of both cell types at 10 mg/ml. At the individual cell level, fructose-1,6-diphosphate is nonstimulatory to proliferation of endothelial cells while inhibiting migration, and it acts on smooth muscle cells by inhibiting both proliferation and migration.

Animals↗

PubMed1999

Mentoring program for minority faculty at the University of Pennsylvania School of Medicine.

Research indicates that having a faculty mentor and being part of an active network of peers are critical ingredients of successful academic medicine careers. Minority physicians, however, often do not have mentors, and the problem is greatest for minority groups underrepresented in medicine. The University of Pennsylvania School of Medicine in 1994-1996 undertook to learn the extent of mentoring programs in its departments and divisions and to compare the experiences of underrepresented-minority faculty and others. The results were used to establish a system for mentoring and networking support for minority faculty members. Examining the reports of division and department heads on their formal mentoring programs, it was clear that these leaders considered a mentor essential for career development, but many reported having no systematic plan for mentors for junior faculty. In looking at the reported experiences of minority and non-minority assistant professors (matched for promotion track, department, appointment date, and, where possible, gender), it was found that approximately half of either group did not have mentors. As a result of this information, the school established a faculty development program to meet the faculty members' demonstrated needs: annual career development meetings with new minority faculty; assistance in identifying and assigning mentors; assistance in developing research skills; and monitoring of the retention of minority faculty. As experience with the program produces additional insights into the needs of minority faculty--and particularly of junior faculty--the program will be adjusted and expanded to meet these identified needs.

Adult↗

PubMed1999

Patient attitudes toward undergoing colonoscopy without sedation.

OBJECTIVE: The vast majority of patients undergoing colonoscopy in the United States are given sedation. There are a number of potential advantages to performing colonoscopy without sedation. We sought to determine the attitude of patients toward unsedated colonoscopy in our three practice settings (a university medical center, a cancer center, and a Veterans Affairs medical center), and to see if there were factors that predicted willingness to try it. METHODS: Four-hundred thirty-four adult patients undergoing outpatient colonoscopy completed questionnaires before and after their procedures providing demographic information and assessing willingness to undergo colonoscopy without sedation. Patients were routinely given meperidine and midazolam for their procedures unless they specifically requested that they be unsedated (10 patients). RESULTS: Only 16.9% of our patients were willing to undergo colonoscopy on their preprocedure questionnaire. Willingness increased modestly on the postprocedure questionnaire to 22.6% (p = 0.01). Logistic regression analysis disclosed that male gender, having a college degree, low anxiety based on preprocedure anxiety scales, and lower doses of sedative drugs used during colonoscopy were the best predictors of willingness to undergo colonoscopy without sedation in the future. CONCLUSIONS: Only about a fifth of patients undergoing colonoscopy in our three practice settings expressed a willingness to try colonoscopy unsedated. Male gender, higher levels of education, and low anxiety scores on simple scales of preprocedure anxiety may help to predict willingness. Efforts to substantially increase the frequency of patients willing to undergo colonoscopy without sedation will likely require increased patient counseling and education.

Adult↗

PubMed1999

Reptilian melanomacrophages function under conditions of hypothermia: observations on phagocytic behavior.

Melanomacrophages (MMs) were removed from livers of turtles of three North American families and cultured. J774 mammalian macrophages were similarly cultured and the MMs were exposed to E. coli(fluor) at approximately 2, 7, 27, and 37 degrees C. At least one third of the MMs continued to function at the low temperatures where less than 2% of the mammalian cells incorporated bacteria deeply into the cytoplasm. In most instances, when the bacteria were not internalized deeply into the cytoplasm, they became stationary just inside, or within, the cell membrane. The MMs were significantly less efficient than the mammalian cells at 37 degrees C and significantly more efficient at 2 and 7 degrees C. In general, it appears that MMs are never as efficient as mammalian macrophages under the most ideal temperatures for the cell but they are capable of functioning at reasonable levels at temperature extremes. The observations are suggestive of a genetic mechanism functioning in the MMs that is rarely expressed in J774 cells under conditions of hypothermia. MMs in vitro and probably in vivo consume bacteria, fungi, attach to helminth eggs, and consume old erythrocytes.

Animals↗

PubMed1999

Phosphorylation of the cap-binding protein eukaryotic translation initiation factor 4E by protein kinase Mnk1 in vivo.

Eukaryotic translation initiation factor 4E (eIF4E) binds to the mRNA 5' cap and brings the mRNA into a complex with other protein synthesis initiation factors and ribosomes. The activity of mammalian eIF4E is important for the translation of capped mRNAs and is thought to be regulated by two mechanisms. First, eIF4E is sequestered by binding proteins, such as 4EBP1, in quiescent cells. Mitogens induce the release of eIF4E by stimulating the phosphorylation of 4EBP1. Second, mitogens and stresses induce the phosphorylation of eIF4E at Ser 209, increasing the affinity of eIF4E for capped mRNA and for an associated scaffolding protein, eIF4G. We previously showed that a mitogen- and stress-activated kinase, Mnk1, phosphorylates eIF4E in vitro at the physiological site. Here we show that Mnk1 regulates eIF4E phosphorylation in vivo. Mnk1 binds directly to eIF4G and copurifies with eIF4G and eIF4E. We identified activating phosphorylation sites in Mnk1 and developed dominant-negative and activated mutants. Expression of dominant-negative Mnk1 reduces mitogen-induced eIF4E phosphorylation, while expression of activated Mnk1 increases basal eIF4E phosphorylation. Activated mutant Mnk1 also induces extensive phosphorylation of eIF4E in cells overexpressing 4EBP1. This suggests that phosphorylation of eIF4E is catalyzed by Mnk1 or a very similar kinase in cells and is independent of other mitogenic signals that release eIF4E from 4EBP1.

3T3 Cells↗

PubMed1999

A comparison of florfenicol and tilmicosin for the treatment of undifferentiated fever in feedlot calves in western Canada.

A field trial was performed under commercial feedlot conditions in western Canada to compare the efficacy of florfenicol and tilmicosin for the treatment of undifferentiated fever (UF) in calves that received metaphylactic tilmicosin upon arrival at the feedlot. One thousand and eighty recently weaned, auction market derived, crossbred beef calves suffering from UF were allocated to one of 2 experimental groups as follows: florfenicol, which was intramuscular (i.m.) florfenicol administered at the rate of 20 mg/kg body weight (BW) at the time of allocation (Day 0) and again 48 h later, or tilmicosin, which was subcutaneous (s.c.) tilmicosin administered once at the rate of 10 mg/kg BW on day 0. Five hundred and forty-four animals were allocated to the florfenicol group and 536 animals were allocated to the tilmicosin group. The chronicity, wastage, overall mortality, and bovine respiratory disease (BRD) mortality rates were significantly (P < 0.05) lower in the florfenicol group than in the tilmicosin group. There were no significant (P > or = 0.05) differences in first UF relapse, second UF relapse, hemophilosis mortality, or miscellaneous mortality rates between the florfenicol and tilmicosin groups. Average daily gain (ADG) from arrival at the feedlot to the time of implanting and ADG from allocation to the time of implanting were significantly (P < 0.05) lower in the florfenicol group as compared with the tilmicosin group. There were no significant (P > or = 0.05) differences in arrival weight, allocation weight, implanting weight, or ADG from arrival to allocation between the experimental groups. In the economic analysis, there was an advantage of $18.83 CDN per animal in the florfenicol group. The results of this study indicate that florfenicol is superior to tilmicosin for the treatment of UF because of lower chronicity, wastage, overall mortality, and BRD mortality rates. However, interpretation of these observations must take into consideration the fact that these calves received meta-phylactic tilmicosin upon arrival at the feedlot, which is a standard, cost-effective, management procedure utilized by feedlots in western Canada.

Animals↗

PubMed1998

Age, depressive symptoms, and rheumatoid arthritis.

OBJECTIVE: To examine the relationship between age and depression in persons with rheumatoid arthritis (RA). METHODS: Two separate outpatient cohorts of persons with RA were studied. In both studies, the Center for Epidemiological Studies Depression Scale was administered to all subjects, and the prevalence of depressive symptoms was determined by age group. In the second study, data on additional measures of disease activity, pain, life stress, and coping were collected for use in multiple linear regression analyses. RESULTS: In both samples, a significant correlation between age and depression was found; younger persons (age < or = 45 years) with RA were significantly more depressed, even after controlling for potentially confounding variables such as sex, marital status, antidepressant medication, arthritis medication, functional class, and disease duration. CONCLUSION: The findings show that younger persons with RA are at higher risk for depressive symptoms than their older counterparts.

Adaptation, Psychological↗

PubMed1998

Predictors of subjective fatigue among individuals with rheumatoid arthritis.

OBJECTIVE: To examine a range of variables potentially associated with rheumatoid arthritis (RA)-related fatigue and to determine which variables best predict subjective fatigue. METHODS: Measures of fatigue, disease activity, pain, and various psychosocial factors were gathered from 73 individuals with RA. Correlations between fatigue and other variables were examined, and the "best" predictors of fatigue were determined with multiple regression analyses. RESULTS: Many of the variables that were significantly correlated with fatigue had a psychosocial character. Moreover, the "best" predictors of increased fatigue were higher levels of pain, more depressive symptoms, and female sex. Longer symptom duration, less perceived adequacy of social support, and less disease activity were significant predictors of fatigue, over and above the "best" model. CONCLUSION: RA-related fatigue appears to be strongly associated with psychosocial variables, apart from disease activity per se. Correspondingly, treatment of fatigue may be enhanced by interventions that address relevant cognitive and behavioral dimensions.

Aged↗

PubMed1998

Disease and family contributors to adaptation in juvenile rheumatoid arthritis and juvenile diabetes.

OBJECTIVE: Research in the areas of pediatric rheumatology and pediatric chronic illness has emphasized comprehensive models of adaptation involving risk and resistance factors. This study examined adaptation, within this framework, among a large sample of children with chronic illness and children without chronic illness. METHODS: A comprehensive battery of adaptation measures was administered to a sample of 107 children with juvenile rheumatoid arthritis, 114 children with insulin-dependent diabetes mellitus, and 88 healthy controls. RESULTS: Medical diagnosis was associated with mothers' depression and a composite measure of parental (mother and father) distress and passive coping. Children's emotional and behavioral functioning was not related to medical diagnosis, but mothers' depression and parental distress were associated with child behavior problems. CONCLUSION: Because parental distress was associated with child functioning, interventions to ameliorate parental distress may have beneficial effects on the children's behavior and on parents' reactions to their children.

Adaptation, Psychological↗

PubMed1998

Biofeedback/relaxation training and exercise interventions for fibromyalgia: a prospective trial.

OBJECTIVE: To compare the effectiveness of biofeedback/relaxation, exercise, and a combined program for the treatment of fibromyalgia. METHODS: Subjects (n = 119) were randomly assigned to one of 4 groups: 1) biofeedback/relaxation training, 2) exercise training, 3) a combination treatment, or 4) an educational/attention control program. RESULTS: All 3 treatment groups produced improvements in self-efficacy for function relative to the control condition. In addition, all treatment groups were significantly different from the control group on tender point index scores, reflecting a modest deterioration by the attention control group rather than improvements by the treatment groups. The exercise and combination groups also resulted in modest improvements on a physical activity measure. The combination group best maintained benefits across the 2-year period. CONCLUSION: This study demonstrates that these 3 treatment interventions result in improved self-efficacy for physical function which was best maintained by the combination group.

Activities of Daily Living↗