Biomedical subjects

J C Johnson

Publications and source records attributed to J C Johnson.

At least 55 records · Page 3Linked to original sources

PubMed1998

Trajectories of adaptation in pediatric chronic illness: the importance of the individual.

This study used individual growth modeling to examine individual difference and group difference models of adaptation. The adaptation of 27 children with juvenile rheumatoid arthritis (JRA) and 40 children with insulin-dependent diabetes mellitus (IDDM) was tracked for 18 months from diagnosis. A control group of 62 healthy children was followed over the same time period. Clustering procedures indicated that child and family adaptation could be described by a number of distinct adaptation trajectories, independent of diagnostic group membership. In contrast, parental adaptation trajectory was associated with diagnostic group membership and control over disease activity for the JRA group and with diagnostic group membership for healthy controls. The observation of common patterns across trajectory sets, as well as the finding that trajectories were differentially related to a number of variables of interest, support the use of trajectories to represent adaptation to chronic disease.

Adaptation, Psychological↗

PubMed1998

Extending the pipeline for minority physicians: a comprehensive program for minority faculty development.

Medical schools must become more successful in training minority faculty. Minority faculty development programs at schools of medicine must involve trainees from the undergraduate years (if not before) through junior faculty and must involve MD and combine-degree (MD-PhD) students. The authors describe the comprehensive minority faculty development program at the University of Pennsylvania School of Medicine, which involves minority undergraduates, medical students, residents, fellows, and faculty. This program provides the administrative staff and research methodologists to assist trainees at all levels across all departments in the school of medicine. The principal student recruitment program is the undergraduate premedicine enrichment program. The medical student component provides general counseling, research development, and activities to enhance performance in the clinical courses. The components for advanced trainees (residents, fellows, and postdoctoral trainees) and faculty consist of training in research methods, mentoring, teaching skills, and scientific writing skills. Through this program, the University of Pennsylvania School of Medicine has increased the number of under-represented minority faculty by 32% since 1993-94 and created an environment conducive to the professional growth and development of minority faculty.

Black or African American↗

PubMed1998

In vitro culture of melanomacrophages from the spleen and liver of turtles: comments on melanomacrophage morphology.

Melanomacrophages were extracted and cultured from the spleen and liver of three turtle species representing three divergent families, the Chelydridae, Emydidae, and Trionychidae. Homogeneous cultures were obtained by repeatedly forcing minced, frequently washed tissue through a sterile screen and separating the resulting cells by centrifugation. The cells were surprisingly resistant to lysis and were maintained in culture for over 12 weeks where culture characteristics, appearance, and longevity from these two organs were similar. They attached to the T flask substrate as individual cells and aggregates and spread out 14 days after being placed in media. Ridges and ruffles at the distal ends of pseudopodia and the cell surface along with a zone of clearing attest to the cells' phagocytic nature. A few melanomacrophages from both organs underwent mitosis 14 days after treatment with granulocyte macrophage colony-stimulating factor but it is possible that other factors contributed to stimulation of cell division.

Animals↗

PubMed1998

Internal resection of posterior uveal melanomas.

AIMS: To evaluate the safety and efficacy of internal resection in the treatment of malignant melanoma of the choroid. METHODS: 32 consecutive patients with histopathologically proved malignant choroidal melanomas were treated with internal resection. 29 of the 32 (90.6%) tumours were within 2 disc diameters of the optic nerve or fovea. The surgery was performed at two university centres by one of the authors. Follow up was between 1 and 85 months (mean 40.1 months). RESULTS: Three patients developed distant metastases and died of malignant melanoma (metastatic and mortality rate 9.4%). In one case, distant metastases developed in association with an intraocular recurrence. There have been no other intraocular recurrences. The most common postoperative complication was vitreous haemorrhage, which occurred in 12 patients (37.5%); cataract occurred in eight eyes; and three patients developed retinal detachment postoperatively. Three of the operated eyes have been enucleated (9.4%); a total of four (12.5%) have lost light perception. 10 patients (31.2%) had visual acuities of 6/60 or better and 18 of 32 (56.3%) were between 6/120 and light perception. CONCLUSION: These data suggest that the internal resection of posterior uveal melanomas is a reasonable globe saving management option. This treatment modality is particularly well suited to elevated tumours in close proximity to the optic nerve or fovea.

Adult↗

PubMed1998

Longitudinal studies of behavior and performance during a winter at the South Pole.

BACKGROUND: Evidence of a specific pattern of performance decrement in isolated and confined (ICE) environments has not been consistently demonstrated in previous research. HYPOTHESIS: Decrements in performance in ICE environments: a) occur in a linear, dose-response manner; b) occur in stages; or c) do not occur at all. METHODS: There were 83 members of the United States Antarctic Program who spent an austral winter at the Amundsen-Scott South Pole Station (90 degrees S) between 1991 and 1994 and completed the Profile of Moods States (POMS) once a month for an 8-mo period from March through October. RESULTS: Over the entire 8-mo period, there was a decline in depression (p = 0.007) and vigor (p < 0.0001), and an increase in fatigue (p = 0.059) and tension-anxiety (p = 0.075). Of these four measures, only vigor exhibits a linear pattern. Mean scores for tension-anxiety and fatigue were lower during the first half of the winter than the second half (p = 0.074 and 0.077, respectively). In comparisons between each quarter and the remaining three quarters, averaged mean tension-anxiety scores and fatigue scores were lower during the second quarter (p = 0.009 and 0.03, respectively), and higher during the fourth quarter (p = 0.025 and 0.035, respectively) than during the previous three quarters combined. CONCLUSIONS: The duration of optimal performance in isolated and extreme environments and the explanation for changes in performance during long duration assignments in such environments both depend on what behavioral measure is used to assess performance.

Acclimatization↗

PubMed1998

A comparison of the clinical field efficacy and safety of florfenicol and tilmicosin for the treatment of undifferentiated bovine respiratory disease of cattle in western Canada.

We compared the field efficacy of a new antibiotic, florfenicol, with tilmicosin in the treatment of naturally occurring undifferentiated bovine respiratory disease. Beef calves with rectal temperatures greater than 40.5 degrees C and signs compatible with undifferentiated bovine respiratory disease were entered into the trial. Calves were randomly assigned to receive either florfenicol (20 mg/kg bodyweight intramuscularly; 2 injections 48 h apart) or tilmicosin (10 mg/kg bodyweight subcutaneously; 1 injection). Clinical measures of efficacy included mortality, rectal temperature, illness index score, assessment of treatment success or failure, and the number of relapses or reinfections. Performance was assessed based on weight gains from day 0 to day 90. Two hundred and twenty calves entered the trial; 112 received florfenicol and 108 received tilmicosin. Seventeen deaths occurred between day 0 and day 90, but only 10 during the 28-day trial period. Seven calves receiving tilmicosin died, compared with 3 receiving florfenicol (P = 0.20). Of the 220 initial treatments, 45 (20%) were categorized as treatment failures; 27 in the tilmicosin group and 18 in the florfenicol group (P = 0.10). The number of calves experiencing a 2nd relapse was significantly different, with 17 of 30 (57%) calves on tilmicosin compared with 7 of 26 (27%) calves on florfenicol relapsing at least twice (P = 0.02). Average daily gains over 90 days were 1.55 kg/day for florfenicol-treated calves and 1.51 kg/day for tilmicosin-treated calves. No significant adverse reactions were noticed with either drug. Results indicate that florfenicol and tilmicosin are comparable in the treatment of undifferentiated bovine respiratory disease in western Canada.

Animals↗

PubMed1997

Identification and characterization of mutations in Ha-Ras that selectively decrease binding to cRaf-1.

The oncoprotein Ras transforms cells by binding to one or more effector proteins. Effector proteins have been identified by their ability to bind to Ras in the GTP but not GDP form, and by their requirement for the Ras effector domain for binding. The best understood Ras effectors are serine/threonine kinases of the Raf family, but other candidate Ras effectors, including a Ral guanine nucleotide dissociation stimulator and phosphatidylinositol 3-kinase (PI3 kinase) have also been identified. To investigate the mechanism of binding of cRaf-1 to Ras, and to investigate the roles of other candidate Ras effectors in transformation, we have isolated and characterized mutants of activated Ras with decreased binding to cRaf-1 relative to other candidate effectors. Examination of these mutants indicates that surface-exposed residues of Ras outside the minimal effector domain interact differentially with cRaf-1 and other Ras-binding proteins, and that fibroblast transformation correlates with cRaf-1 binding and mitogen-activated protein (MAP) kinase activation. Furthermore, activation of PI3 kinase can occur in the absence of significant MAP kinase activation, suggesting that PI3 kinase activation is a primary effect of Ras.

3T3 Cells↗

PubMed1997

Organization of the zona incerta in the macaque: an electron microscopic study.

BACKGROUND: The zona incerta (ZI) receives projections from many telencephalic and brainstem structures. On the basis of its connectivity and physiology, this nucleus has been implicated in the control of saccadic eye movements. Because of the complexity of its afferent signals and its simple efferent signal, there must be much local interaction within the ZI to integrate these various afferents. The purpose of this study was to investigate, at the ultrastructural level, whether the ZI contains the anatomical substrata which could subserve the control of eye movements. METHODS: Blocks of tissue from the ZI of macaque monkeys were prepared for electron microscopy using standard techniques. Some of these animals were taken specifically for electron microscopy. Others had received injections of tracer substances and were prepared for electron microscopy subsequent to tracer visualization. RESULTS: Cell bodies of medium-large neurons were found in our preparations. They have large nucleoli and relatively small volumes of karyoplasm. Cell bodies and dendrites of all sizes have many synaptic contacts. Three types of synaptic profiles were found, designated Types 1, 2, and 3. Type 1 profiles are symmetrical and contact cell bodies and small dendrites. Type 2 profiles are thought to be presynaptic dendrites and may have symmetrical or asymmetrical contacts. Type 3 profiles are asymmetrical and primarily contact small dendrites. Many synapses contacted vesicle-containing profiles. In some cases, it was clear that these profiles participated in serial synapses on presumptive presynaptic dendrites. Other profiles appeared to be axoaxonic contacts. CONCLUSIONS: Afferent and efferent signals are likely to be modulated extensively within the ZI. Therefore, there needs to be complex interactions between neuronal elements of the ZI and its afferents. This study demonstrates that this nucleus possesses the structural substrata to subserve diverse roles, such as the gating of saccadic eye movements.

Animals↗

PubMed1997

Definition of agitation following traumatic brain injury: I. A survey of the Brain Injury Special Interest Group of the American Academy of Physical Medicine and Rehabilitation.

OBJECTIVE: To determine national patterns of defining agitation after traumatic brain injury (TBI) by physiatrists with expressed interest in treating TBI survivors. DESIGN: A random sample of 70% of the members of the Brain Injury Special Interest Group (SIG) of the American Academy of Physical Medicine and Rehabilitation (AAPM&R) were surveyed by telephone. RESULTS: The 129 members who responded yielded an 82% response rate. Respondents rated 18 characteristics from established rating scales on a 5-point scale according to each characteristic's relation to its clinical definition of agitation. Physical aggression, explosive anger, increased psychomotor activity, impulsivity, verbal aggression, disorganized thinking, perceptual disturbances, and reduced ability to maintain or appropriately shift attention were rated by at least 50% of the sample as very important or essential to agitation. Delirium, as defined in the Diagnostic and Statistical Manual of Mental Disorders (DSM), has been proposed as a standard definition of agitation. The degree to which all characteristics from the 3rd revised edition of the DSM (DSM-IIIR), considered together, were perceived to relate to agitation predicted 24% of the degree to which the term "delirium" was perceived to relate to agitation (Canonical correlation r = .48, p = .0002). Physicians' ratings of individual delirium characteristics from the DSM-IIIR were examined to determine if a sufficient number were similarly ranked to fulfill the diagnostic criteria for delirium. A significant number of physicians rated diagnostic criteria for delirium in one direction, yet did not rank the term "delirium" accordingly (McNemar's p = .04). CONCLUSIONS: There is considerable variation among physiatrists in their rating of characteristics that define agitation. Many define agitation during the acute recovery phase as posttraumatic amnesia plus an excess of behavior such as aggression, disinhibition, and/or emotional lability. Less support was given to defining agitation by the DSM-IIIR or DSM-IV diagnostic criteria for delirium. Delirium appears related to, but is not sufficient for, a diagnosis of agitation.

Adult↗

PubMed1997

Measurement and treatment of agitation following traumatic brain injury: II. A survey of the Brain Injury Special Interest Group of the American Academy of Physical Medicine and Rehabilitation.

OBJECTIVE: Determine national patterns of measuring and treating agitation after traumatic brain injury (TBI) by physiatrists with expressed interest in treating TBI survivors. DESIGN: A 70% random sample of members of the Brain Injury Special Interest Group of the American Academy of Physical Medicine and Rehabilitation was surveyed by telephone. MAIN OUTCOME MEASURE: The survey instrument was designed to determine the most common pharmacologic interventions for agitation and, where possible, match each drug with the target behavioral and cognitive characteristics for which it is prescribed. Data were also collected on the manner in which participants measured agitation and judged treatment efficacy. RESULTS: One hundred twenty-nine of 157 responded, yielding an 82% response rate. The majority of respondents were not measuring agitation in a standard fashion. The five most frequently prescribed drugs by the expert stratum were carbamazepine, tricyclic antidepressants (TCAs), trazodone, amantadine, and beta-blockers. In comparison, the nonexperts most often reported prescribing carbamazepine, beta-blockers, haloperidol, TCAs, and benzodiazepines. Desyrel (p = .06) and amantadine (p = .001) were significantly more likely to be chosen by experts than by nonexperts. Experts chose haloperidol significantly less often than nonexperts (p = .01). Prescription of sedating drugs such as haloperidol or benzodiazepines was not found to be associated with the acuity of injury of TBI patients in the respondent's practice, practice setting, or years of practice since completing residency. Choice of haloperidol to treat agitation was not significantly associated with the degree to which explosive anger, verbal aggression, or physical aggression were considered important to the respondent's definition of agitation. CONCLUSIONS: The majority of physiatrists surveyed did not formally measure agitation. Treatment strategies differ significantly between general physiatrists and those who specialize in the treatment of patients with TBI. The breadth of pharmacologic agents and strategies identified in this survey probably reflects the lack of research specific to the pathophysiology of the disorder of posttraumatic agitation.

Adult↗

PubMed1997

Mortality of veteran participants in the CROSSROADS nuclear test.

Operation CROSSROADS, conducted at Bikini Atoll in 1946, was the first post World War II test of nuclear weapons. Mortality experience of 40,000 military veteran participants in CROSSROADS was compared to that of a similar cohort of nonparticipating veterans. All-cause mortality of the participants was slightly increased over nonparticipants by 5% (p < .001). Smaller increases in participant mortality for all malignancies (1.4%, p = 0.26) or leukemia (2.0%, p = 0.9) were not statistically significant. These results do not support a hypothesis that radiation had increased participant cancer mortality over that of nonparticipants.

Humans↗

PubMed1997

Predictors of patient cooperation during gastrointestinal endoscopy.

We examined a number of patient variables, including three different scales of preprocedure patient anxiety, to determine which best predicted patient cooperation and satisfaction with gastrointestinal endoscopy. We prospectively evaluated 251 patients undergoing outpatient diagnostic esophagogastroduodenoscopy and colonoscopy under conscious sedation. All were given a questionnaire on arrival to our endoscopy center that included three measures of preprocedure anxiety: (a) a single question asking how anxious the patient was (termed "Anxiety I" scale); (b) a visual linear analog scale of anxiety; and (c) the Hospital Anxiety and Depression scale. Patient cooperation during the procedure was rated by the attending endoscopist. Patients were telephoned the next day to complete a questionnaire assessing their endoscopic experience. Logistic regression analysis was used to construct models for predicting which patients were most likely to have difficulty during their procedures from both the endoscopists' and the patients' standpoint. Statistical analysis identified three parameters that by themselves significantly correlated with patient cooperation during endoscopy: age (p = 0.008), Anxiety I scale (p = 0.03), and visual linear analog anxiety score (p = 0.02). When used together, age, type of procedure, and Anxiety I scale were the best predictors of patient cooperation from the standpoint of the endoscopist. Age, type of procedure, Anxiety I scale, and education level were the best predictors of satisfaction with endoscopy from the perspective of the patient. Good cooperation during endoscopy was associated with greater patient satisfaction.

Anxiety↗

PubMed1997

Yield, composition, and in vitro digestibility of temperate and tropical corn hybrids grown as silage crops planted in summer.

Following the harvest of corn silage crops that were planted in spring, second crops of one temperate and four tropical corn hybrids were planted under conditions of minimum tilling in four replications on August 3, 1992 and harvested on October 11, 1992 (yr 1). During the 2nd yr, second crops were planted on July 21, 1993 and harvested on October 19, 1993. Dry matter yields of the hybrids ranked similarly for both years but differed among hybrids, ranging from 7800 to 11,430 kg/ha (yr 1) and from 8470 to 13,150 kg/ha (yr 2). The temperate hybrid yielded 20% (yr 1) and 26% (yr 2) less than the lowest yielding tropical hybrid. The proportion of grain in the dry matter (DM) differed across hybrids, ranging from 14.3 to 32.2% during yr 1 and from 18.0 to 32.4% during yr 2. Composition of the DM, excluding grain, also differed for the hybrids: acid detergent fiber ranged from 38.0 to 42.2% during yr 1 and 40.0 to 48.8% during yr 2; in vitro digestible DM ranged from 60.9 to 65.1% during yr 1 and from 53.0 to 64.6% during yr 2. The temperate hybrid was the highest in acid detergent fiber and the lowest in in vitro digestible DM. Lower digestibility during yr 2 was attributed to disease, which infected 24.9 to 40.4% of the foliage of tropical hybrids and 84.3% of the temperate hybrid. Whole plant DM digestibilities differed narrowly in yr 1 (68.8 to 70.4%) but differed widely in yr 2 (62.2 to 69.9%). There were important differences among yields and compositions of tropical hybrids planted in summer, but all were superior to the temperate hybrid.

Agriculture↗

PubMed1997

Determination of an effective dose of eltenac and its comparison with that of flunixin meglumine in horses after experimentally induced carpitis.

OBJECTIVES: To titrate a clinically effective eltenac dosage (0.1, 0.5, and 1.0 mg/kg of body weight), compared with vehicle only, and to compare efficacy of the most effective eltenac dosage with that of 1.1 mg of flunixin meglumine/kg. ANIMALS: 40 healthy horses, ranked after model induction on the basis of lameness severity, were randomly assigned to 5 treatment groups, with 4 replicates of 10 horses each. PROCEDURE: On day -5, after surgical preparation of the left carpal region, 0.7 ml of Freund's complete adjuvant was injected into the intercarpal space. Horses were observed daily, from the day of carpitis induction to day 0, when stride length was used as the method of ranking horses for randomization to treatment assignment. Treatments were administered i.v. once daily for 3 consecutive days, starting on day 0. Prior to carpitis induction on day -5, and at time 0 (pretreatment), 2, 4, 12, 24, 36, 48, 60, 72, and 96 hours after treatment initiation, resting respiratory rate and pulse, rectal temperature, carpal circumference, carpal flexion angle, stride length, carpal hyperthermia, and signs of carpal pain were recorded. RESULTS: Compared with the vehicle and 0.1 mg of eltenac/kg, 0.5 and 1.0 mg/kg caused statistically significant improvements (ie, reduction of carpal circumference, increase in carpal flexion angle, and increase in stride length of the affected limb), but values did not differ significantly between the 2 dosages. Thus, a dose-response plateau for eltenac was reached at 0.5 mg/kg. Comparison with flunixin meglumine at a dosage of 1.1 mg/kg did not indicate significant differences between the 2 treatment groups at the pivotal time of 96 hours for carpal circumference, carpal flexion angle, stride length, carpal hyperthermia, and signs of carpal pain. Adverse reactions were not observed. CLINICAL RELEVANCE: Under conditions of this study, a dosage plateau for eltenac was determined (0.5 mg/kg) that was statistically equivalent to eltenac (1.0 mg/kg) and flunixin meglumine (1.1 mg/kg) in a 3-day i.v. dosing regimen.

Analysis of Variance↗

PubMed1997

The occurrence of endometrial adenocarcinoma in a patient with basal cell nevus syndrome.

Basal cell nevus syndrome is rare multisystem disorder. Its genital implications in female patients is thought to be limited to ovarian fibroma. This article describes endometrial adenocarcinoma in association with basal cell nevus syndrome in a 37-year-old female with multiple basal cell carcinomas, mandibular and maxillary bone cysts, right ovarian fibroma, and scoliosis. Histopathologic examination of her endometrial biopsy, performed for irregular uterine bleeding, revealed endometrial hyperplasia. Her bleeding failed to respond to progestin therapy, and a repeat endometrial biopsy revealed a well differentiated endometrial adenocarcinoma. Health-care providers are encouraged to refer these patients to gynecologists. Regular gynecologic examination as well as appropriate evaluation of abnormal menstrual bleeding should be emphasized.

Adenocarcinoma↗

PubMed1996

Hospital smoking bans and employee smoking behavior: Results of a national survey.

OBJECTIVE: To examine the impact of workplace smoking bans on smoking behavior of employees. PARTICIPANTS: A total of 1469 current or former smokers (intervention group) employed in smoke-free hospitals and 920 current or former smokers (comparison group) employed in non-smoke-free workplaces were surveyed to determine smoking behavior. DESIGN: This cross-sectional study is part of a larger, ongoing prospective study. The study design was quasi-experimental. We randomly selected sites consisting of a hospital and a corresponding community. Furthermore, we randomly selected subjects from hospitals and their corresponding communities. MAIN OUTCOME MEASURES: Postban quit ratio and progression along the stages-of-change continuum. METHODS: The Cox proportional hazards model was used to compare the postban quit ratio between the intervention and comparison groups. The Cochran-Mantel-Haenszel analysis of variance statistic was used to compare groups on the stages-of-change variables. RESULTS: Beginning with the smoking ban and continuing for 5 years after implementation, statistically significant differences in the postban quit ratio were observed between employees of smoke-free hospitals who were smokers and counterparts in the community (P<.001). Despite preban differences in smoking intensity, the overall difference in postban quit ratios remained significant even after multivariate adjustment for socioeconomic, demographic, and smoking intensity variables. For those sites that were 5 years postban, the quit ratio was 0.506 in smoke-free workplaces compared with 0.377 in workplaces where smoking was permitted. In all but 1 category, the intervention group was further along the stages-of-change continuum toward quitting smoking than the comparison group (P<.001). CONCLUSION: American hospitals' experiences with smoking bans, which directly affect more than 5 million workers, should be examined by other industries as a method of improving employee health. Workplace smoking bans could also be effective in saving lives, reducing health care costs, addressing safety concerns, and decreasing operating and maintenance expenses of employers.

Analysis of Variance↗

PubMed1996

Self-efficacy predicting outcome among fibromyalgia subjects.

OBJECTIVES: This study examined whether pretreatment self-efficacy and pre- to post-treatment changes in self-efficacy predict post-treatment tender point index, disease severity, pain, and physical activity. METHODS: One hundred nine subjects with fibromyalgia were assessed before and after a 6-week training intervention. Measures included tender point index, physician ratings of disease severity, the visual analog scale for pain, the Physical Activities subscale of the Arthritis Impact Measurement Scales, and the Arthritis Self-Efficacy Scale. RESULTS: Pretreatment self-efficacy significantly predicted post-treatment physical activity, with higher self-efficacy associated with better physical activity outcome. Changes in self-efficacy significantly predicted post-treatment tender point index, disease severity, and pain; improvements in self-efficacy were associated with better outcomes on each measure. CONCLUSIONS: Higher levels of self-efficacy are associated with better outcome, and may mediate the effectiveness of rehabilitation-based treatment programs for fibromyalgia.

Activities of Daily Living↗

PubMed1996

Risk factors for depression in rheumatoid arthritis.

OBJECTIVE: To identify risk factors for the development of depression in persons with rheumatoid arthritis (RA). METHODS: Subjects were divided into depressed versus nondepressed groups on the basis of the Center for Epidemiologic Studies-Depression Scale; a range of psychological, pain-related, disease-related, and demographic variables were analyzed to predict depression. Both cross-sectional and longitudinal predictive models were examined. RESULTS: A series of analyses, including multiple logistic regression, found that the optimal predictors of depression in RA were average daily stressors, confidence in one's ability to cope, and degree of physical disability. The model was successfully cross-validated on separate data sets (i.e., same subjects at different time points). CONCLUSION: All of the identified risk factors for depression in RA are preventable to some extent and, therefore, should be addressed in comprehensive, rheumatology team care.

Aged↗