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Biomedical subjects

R J Harrison

Publications and source records attributed to R J Harrison.

At least 37 records · Page 2Linked to original sources
PubMed1998

Overt categorical aggression in referred children and adolescents.

OBJECTIVE: To investigate descriptive and predictive correlates of aggression in children and adolescents who exhibit a high frequency of daily physical assault after admission to a structured residential treatment program and to examine correlations between subcategories of overt categorical aggression (OCA) in the same population. METHOD: Fifty-one admissions to a residential treatment program were assessed for frequency of physical assault after admission; analyses were corrected for length of stay. Patients with a high frequency of daily assault were compared with patients with a low frequency of daily assault on variables assessing demographics, history, family, concurrent behavior, treatment, and outcome. RESULTS: A high prevalence of OCA was found in this sample. Variables assessing history and concurrent behavior were significantly associated and predictive of subjects exhibiting a high frequency of daily physical assault after admission. Physical assault was significantly correlated with verbal aggression, property destruction, and self-injurious behavior. CONCLUSIONS: These findings support the distinctiveness of OCA as a separate subtype of aggression encompassing four subcategories. Further research on treatment, outcome, and associated comorbidity of OCA is warranted.

Adolescent↗
PubMed1997

Bilateral macular holes resulting from septic embolization.

PURPOSE: To report a previously undescribed cause of bilateral macular hole formation. METHOD: Case report. RESULTS: Septic emboli were noted at the center of the macula in both eyes of a 32-year-old man with acute bacterial endocarditis. Bilateral full-thickness macular holes later developed at the site of these retinal lesions. CONCLUSION: This case represents the first report of fundus lesions in septicemia resulting in full-thickness macular hole formation.

Adult↗
PubMed1997

Anabolic-androgenic steroid exposure during adolescence and aggressive behavior in golden hamsters.

Anabolic androgenic steroid (AAS) abuse by adolescents represents a significant health care risk due to the potential for long-term negative physical and psychological sequelae, including increased aggressive behavior. The current experiments examined the effects of AAS use in young male adolescent hamsters (Mesocricetus auratus) and their consequences on aggressive behavior. It was hypothesized that AAS administration during adolescence predisposes hamsters to heightened levels of aggressive behavior (i.e., offensive aggression). To test this hypothesis adolescent male hamsters were administered high doses of synthetic AAS to mimic a 'heavy use' self-administration regimen used by athletes. Immediately following the exposure to AAS hamsters were tested for aggressive behavior using a resident-intruder model. Animals treated with high doses of AAS during their adolescent development showed heightened measures of offensive aggression i.e., decreased latency to bite and increased total number of attacks and bites) during the test period, while measures of total activity (total contact time) between the animals remained unchanged. AAS-treated males did not differ in body weight from controls, suggesting that the increased aggression was not due to increased body mass. The results of this study show that exposure to AAS during adolescence facilitates aggressive response patterns, but does not alter body weight.

Aggression↗
PubMed1997

Dde-I restriction endonuclease fragmentation: a novel method of generating cDNA probes for in situ hybridization in brain.

We present a novel procedure for detection of low- and high-abundance messenger RNAs in the brain by in situ hybridization histochemistry, by using fragmented double-stranded cDNA as molecular probes. The procedure involves digesting the cDNA of interest with the restriction endonuclease from Desulfocibrio desulfuricans (Dde I digestion), followed by random primed labeling, which generates a family of high specific activity cDNA fragments. This procedure is a rapid, straightforward, and reproducible method of obtaining sensitive probes for in situ hybridization and is generally applicable to the analysis of the expression of a large number of genes. Here we report the use of this procedure to prepare probes for the detection of synapsin I, p150Glued, neurotensin, c-fos, and c-jun mRNAs in brain, using both isotopic and non-isotopic labeling methods. Because this procedure does not require complex recombinant DNA manipulations or oligonucleotide design, it should prove useful to the non-molecular biologist examining the expression of genes in the central nervous system.

Animals↗
PubMed1996

Developmental expression and activities of specific fos and jun proteins are functionally related to osteoblast maturation: role of Fra-2 and Jun D during differentiation.

Developmental studies of oncogene expression implicate the Fos and Jun family of transcription factors in the regulation of bone growth and differentiation. Promoters of many developmentally regulated genes, including osteocalcin, a marker of osteoblast differentiation, contain AP-1 sites that bind Fos/Jun dimers. Here, we demonstrate that the selective expression of fos- and jun-related genes is functionally related to the stage of osteoblast growth and differentiation in vitro. During osteoblast proliferation, nuclear protein levels of all seven activating protein-1 (AP-1) members are maximal. Subsequently, during the period of extracellular matrix maturation, levels decline. In fully differentiated osteoblasts, Fra-2 and (to a lesser extent) Jun D are the principal AP-1 members detectable by Western blot analysis. AP-1 complex composition and binding activity also exhibit developmental changes. All Fos and Jun family members are involved in AP-1 complex formation in proliferating cells, whereas Fra-2 and Jun D predominate in AP-1 complexes in differentiated osteoblasts. Overexpression of Fos and Jun family members in ROS 17/2.8 cells markedly affects the expression of an osteocalcin promoter-chloramphenicol acetyltransferase construct. Coexpression of only one AP-1 pair, Fra-2 and Jun D, stimulated reporter expression, whereas coexpression of other AP-1 pairs down-regulated expression (i.e. c-jun and any Fos family member) or had no effect (i.e. Fra-1 and Jun B). Promoter deletion analyses indicate that these effects are site specific. Consequential effects of Fra-2 on osteoblast differentiation are further demonstrated by antisense studies in which osteoblast differentiation and the development of a bone tissue-like organization were suppressed. Consistent with recent findings suggesting that AP-1 complex composition can selectively regulate gene transcription, our findings demonstrate that differential expression of Fos and Jun family members could play a role in the developmental regulation of bone-specific gene expression and, as a result, may be functionally significant for osteoblast differentiation.

Animals↗
PubMed1995

Synergistic activation of neurotensin/neuromedin N gene expression by c-Jun and glucocorticoids: novel effects of Fos family proteins.

The cis-regulatory region of the neurotensin/neuromedin N (NT/N) gene integrates diverse environmental signals in the neuroendocrine PC12 cell line, resulting in remarkable synergistic regulation. An AP-1 site appears to play a pivotal role in cooperative NT/N gene activation, as mutations in this site decrease responses to all inducer combinations by at least an order of magnitude. Here we report that c-Jun acts synergistically with glucocorticoids to activate the NT/N promoter, and that Fos family proteins have novel regulatory effects on this interaction. Cotransfection of individual pCMV-AP-1 expression plasmids revealed that c-Jun most potently activates the NT/N promoter and that costimulation with dexamethasone results in a further 6- to 12-fold increase in expression. Unlike its general inhibitory effects on glucocorticoid regulation in other systems, c-Fos potentiated activation by glucocorticoids when coexpressed with c-Jun, and Fos B had a similar, but more limited, positive effect. In contrast, Fra-1 reversed the direction of glucocorticoid regulation, and Fra-2 abolished synergism. AP-1, cAMP response element, and glucocorticoid response element motifs are required for full cooperative activation by either c-Jun or c-Jun/c-Fos and glucocorticoids. These results indicate that NT/N promoter activation involves synergistic interactions between specific AP-1 complexes and ligand-activated glucocorticoid receptor, and similar mechanisms may regulate NT/N gene expression in central neurons.

Animals↗
PubMed1992

Work-related cumulative trauma disorders of the upper extremity.

Cumulative trauma disorders due to performance of repetitive tasks account for more than 50% of all occupational illnesses in the United States today. Employees affected by these disorders frequently experience substantial pain and functional impairment that may require a change in occupation. For the employer, these injuries result in loss of productivity and increased costs in the form of higher medical expenses and disability payments for injured workers. Successful treatment of work-related repetitive tissue injuries depends on early diagnosis and appropriate therapy. Prevention requires identifying sites and tasks that place employees at risk of injury and supporting efforts to develop safer work environments.

Arm↗
PubMed1992

Occupational exposures in California wildland fire fighting.

Industrial hygiene measurement of exposures to wildland fire fighters was conducted in northern California during three consecutive fire seasons (1986-1989) in conjunction with three separate health effects studies. Chemicals that were monitored included carbon monoxide, total and respirable particulates, polyaromatic hydrocarbons (PAHs), crystalline silica, aldehydes, and benzene. Measurements were taken at both wildland fires and prescribed (planned) burns. A variety of collection methods were employed--colorimetric detector tubes and a CO monitor were used for direct-reading area measurements; colorimetric diffusion tubes, filter cassettes, sorbent tubes, and passive vapor monitors were used for determining personal time-weighted average exposures. A new screening method (National Institute for Occupational Safety and Health Method 2539) was used to identify the presence of specific aldehydes. Results show that wildland fire fighters may at times be exposed to concentrations of carbon monoxide, total or respirable particulates, or silica at levels near or higher than recommended occupational exposure limits, although group means were generally well below the limits. Time-weighted average formaldehyde levels, measured in a few instances above 0.37 mg/m3 (0.3 ppm), indicate a potential for formaldehyde-induced eye or respiratory irritation under these conditions. Certain characteristics of the work such as high altitude, temperature, and breathing rate; extended work shifts; and additional off-shift exposures suggest that adjustment of 8-hr exposure limits may be necessary to provide adequate protection. In part, because of the rigors of performing industrial hygiene measurements under fire fighting conditions, data are limited and could not be considered representative of the full range of exposures fire fighters may encounter.(ABSTRACT TRUNCATED AT 250 WORDS)

Air Pollutants, Occupational↗
PubMed1992

The effect of smoke inhalation on lung function and airway responsiveness in wildland fire fighters.

The current study was undertaken to evaluate the effect of smoke on forced expiratory volumes and airway responsiveness in wildland fire fighters during a season of active fire fighting. Sixty-three seasonal and full-time wildland fire fighters from five U.S. Department of Agriculture Forest Service (USDAFS) Hotshot crews in Northern California and Montana completed questionnaires, spirometry, and methacholine challenge testing before and after an active season of fire fighting in 1989. There were significant mean individual declines of 0.09, 0.15, and 0.44 L/s in postseason values of FVC, FEV1, and FEF25-75, respectively, compared with preseason values. There were no consistent significant relationships between mean individual declines of the spirometric parameters and the covariates: sex, smoking history, history of asthma or allergies, years as a fire fighter, upper/lower respiratory symptoms, or membership in a particular Hotshot crew. There was a statistically significant increase in airway responsiveness when comparing preseason methacholine dose-response slopes (DRS) with postseason dose-response slopes (p = 0.02). The increase in airway responsiveness appeared to be greatest in fire fighters with a history of lower respiratory symptoms or asthma, but it was not related to smoking history. These data suggest that wildland fire fighting is associated with decreases in lung function and increases in airway responsiveness independent of a history of cigarette smoking. Our findings are consistent with the results of previous studies of municipal fire fighters.

Adult↗
PubMed1992

Synchrotron x-ray diffraction studies of keratoconus corneal stroma.

The aim of this study was to determine any differences in the collagen molecular and fibrillar packing, or the arrangement of the proteoglycans along the fibril axis, in the stroma of keratoconus and control corneas. High and low-angle x-ray diffraction patterns from the fibrillar and molecular packing of collagen in keratoconus and control corneas were obtained using a synchrotron radiation source. The results indicate no difference in interfibrillar spacing between keratoconus and control corneas at normal physiological hydration, or over a range of hydrations (H = 1-11). This unambiguously demonstrates that the thinning of the stroma that occurs in keratoconus is not a result of closer packing of the collagen fibrils in the stroma. Intermolecular spacings were shown to be significantly (P less than 0.001) lower in keratoconus corneas at normal physiological hydration and over a range of hydrations (H = 1-11). Meridional patterns from the axial distribution of electron density along the collagen fibrils were obtained from untreated control and keratoconus corneas and from the corneas after their proteoglycans were stained with cupromeronic blue. Analysis of the integrated intensities of the first nine orders of these reflections show there is a difference in the staining behavior of collagen-associated proteoglycans in control and keratoconus corneas. Determination of the electron density vectors along the collagen fibrils of cupromeronic blue-stained corneas by the use of Patterson functions indicates that the keratoconus corneal stroma has a specific, ordered proteoglycan that is present in lower numbers along the collagen fibrils, and that it stains less with cupromeronic blue or is in a more disordered arrangement than in the controls.

Adult↗
PubMed1991

Fatal injuries at work in California.

We examined deaths due to injury on the job reported from three readily accessible data sources in California for a 1-year period. Of 682 deaths identified as of February 1990 as having occurred on the job in 1983, county coroners identified 607 (89.0%), workers' compensation records identified 294 (43.1%), and the California Occupational Safety and Health Administration investigated 141 (20.7%). Most fatal injuries at work resulted from events that are not covered by current California Occupational Safety and Health Administration standards: transportation vehicle accidents and homicides. Demographic patterns suggest that fatal injuries on the job are nonrandom events, which may be prevented by additions to existing standards or increased enforcement of workplace safety standards and by efforts to target groups at highest risk. Improved surveillance of fatal occupational injuries will require changes in existing reporting mechanisms, similar to those proposed by the US Bureau of Labor Statistics.

Accidents, Occupational↗
PubMed1990

Development of conditional and equivalence relations without differential consequences.

Two experiments were conducted to establish conditional stimulus relations without differential consequences and to test for the emergence of other relations. In Experiment 1, 3 adults responded to match-to-sample displays in which sample-comparison pairs were constant while the second comparison presented with each pair changed periodically across trials. No differential consequences followed any comparison selections. All subjects learned conditional relations between constant samples and comparisons, but results of tests for transitivity in those relations were equivocal. In Experiment 2, 4 children were given unreinforced training and testing similar to that provided to the adults in Experiment 1, with procedural refinements. One child learned conditional relations and demonstrated emergent relations that confirmed the development of two four-member equivalence classes. Another child learned the conditional relations but did not demonstrate any emergent relations reliably. A 3rd child, after reinforced training on two conditional relations, learned four new conditional relations without differential consequences and demonstrated symmetry but not equivalence in the trained relations. The 4th child did not learn the conditional relations. These findings emphasize the importance of careful construction of tests for stimulus equivalence and suggest a need for critical analyses of the apparent emergence of untrained stimulus relations on unreinforced tests that has been observed in several stimulus equivalence studies.

Adult↗
PubMed1989

Association between keratoconus and atopy.

Sixty-seven patients with keratoconus were classified according to atopic status. Keratoconus patients with and without atopy did not differ significantly with regard to sex, age of onset, or rate of keratoplasty, but patients with very high IgE levels were more prone to graft rejection. Atopy was less common in patients with unilateral keratoconus, and keratoconus occurred more frequently on the side of the dominant hand. There was a significantly lower frequency of HLA B7 in the keratoconus group than in the controls. No abnormalities of essential fatty acid metabolism were found in keratoconus patients with or without atopy. There was no social class bias in the group. The study included a brother and sister with keratoconus and atopy, and a non-atopic patient whose identical twin did not have keratoconus.

Asthma↗
PubMed1988

Referral patterns to an ophthalmic outpatient clinic by general practitioners and ophthalmic opticians and the role of these professionals in screening for ocular disease.

Case notes of 1113 consecutive new patients referred to a consultant ophthalmologist at a district general hospital were reviewed to determine the source and efficacy of referrals and the current screening practices of general practitioners and ophthalmic opticians. General practitioners initiated referral in 546 cases (49%) and ophthalmic opticians referral in 439 (39%). Visual loss or visual disturbance was the most important single reason for referral (345 cases; 31%), followed by suspected glaucoma (145 cases; 13%), abnormalities of binocular vision (140; 12.5%), disorders of eyelids or ocular adnexa (127; 11%), and red eye (86; 8%). General practitioners referred many more patients with disorders of the eyelids and adnexa and ophthalmic opticians many more patients with suspected glaucoma. Ophthalmic opticians were far more likely than general practitioners to refer patients with suspected glaucoma correctly. A total of 180 patients (16%) were referred from ocular screening, in 149 cases by ophthalmic opticians and in 10 by general practitioners. Seventy patients had glaucoma or incomplete features of glaucoma, all of them referred by ophthalmic opticians. Of eight diabetic patients referred by ophthalmic opticians, three had asymptomatic disease and in two diabetes was diagnosed as a result of ocular screening. No patient was referred for asymptomatic diabetic retinopathy from screening by general practitioners. Ophthalmic opticians were more likely than general practitioners to diagnose retinopathy requiring photocoagulation. Use of a community based service to screen for glaucoma could save unnecessary consultant outpatient appointments. A similar service could facilitate detection of diabetic retinopathy at a stage when treatment is most effective.

Adolescent↗