PubMed Health⌕ Search

Biomedical subjects

J G Greenwood

Publications and source records attributed to J G Greenwood.

12 recordsLinked to original sources
PubMed2000

Toxicity of insecticides for control of freshwater Culex annulirostris (Diptera: Culicidae) to the nontarget shrimp, Caradina indistincta (Decapoda: Atyidae).

Laboratory evaluations were conducted in southeastern Queensland, Australia, to determine the toxicities of two organophosphate compounds (temephos and pirimiphos-methyl), an insect growth regulator (s-methoprene), and an entomopathogenic bacterium (Bacillus thuringiensis variety israelensis de Barjac [B.t.i.]) to Culex annulirostris (Skuse), an Australian freshwater mosquito vector of arboviruses, and to Caradina indistincta Calman, a co-habiting nontarget shrimp species. S-methoprene and B.t.i. were safest for Cx. annulirostris control with lethal dose ratios (LC95 nontarget/LC95 target) of 3,300 and 846,000, respectively. In contrast, lethal dose ratios for temephos and pirimiphos-methyl were 0.05 and 0.00005, respectively, suggesting that they are environmentally unsuitable. Based on their high lethal dose ratios, s-methoprene and B.t.i. are recommended for control of larval Cx. annulirostris in Australian freshwater habitats.

Animals↗
PubMed1996

Evaluation of Mesocyclops aspericornis (Cyclopoida:Cyclopidae) and Toxorhynchites speciosus as integrated predators of mosquitoes in tire habitats in Queensland.

This study addressed biological control of peridomestic Aedes notoscriptus, known to be a highly effective colonizer of tire habitats and a possible vector of Ross River virus. A laboratory trial of the compatibility of the predators Mesocyclops aspericornis and Toxorhynchites speciosus in small container habitats showed that 4th-instar Tx. speciosus did not significantly affect M. aspericornis mortality. Introduced M. aspericornis and naturally occurring Tx. speciosus were found to form a compatible predator pair for reduction of larval Ae. notoscriptus and Culex quinquefasciatus populations in tire habitats. Over 22 months of field survey, 97% of tires without predators contained mosquito larvae, at a median density of 43 larvae/liter. By comparison, 51% of tires containing both predator species held mosquito larvae at a median density of 4 larvae/liter. Predation by Tx. speciosus persisted for the duration of the study. The inability of the Lake Kurwongbah strain of M. aspericornis to tolerate temperatures of < or = 10 degrees C, which are prevalent in Brisbane during winter, resulted in a failure to deliver persistent reduction of mosquitoes in tires. The temperature-dependent population characteristics of M. aspericornis emphasize the long-recognized importance of matching a biological control candidate's physiological requirements to the environment in which control is sought.

Aedes↗
PubMed1996

Acute toxicity of selected pesticides to the estuarine shrimp Leander tenuicornis (Decapoda:Palaemonidae).

The shrimp Leander tenuicornis is abundant in southeastern Queensland intertidal marsh pools and was chosen as an indicator species for toxicological studies with pesticides. Acute toxicity to this crustacean of temephos and 3 pesticide compounds under evaluation for registration in Australia (Bacillus thuringiensis var. israelensis, s-methoprene, and pyriproxyfen) was tested in 96-h laboratory trials. Temephos was the most toxic compound, with a median lethal concentration (LC50) of 0.01 ppm (0.33 times the estimated field concentration [EFC] for a 15-cm-deep pool). s-Methoprene was the least toxic compound, with an LC50 of 14.32 ppm (1,790 times the EFC). Bacillus thuringiensis var. israelensis and pyriproxyfen produced LC50 values of 60.9 x 10(6) ITU (176 times the EFC) and 0.098 ppm (12.25 times the EFC), respectively.

Animals↗
PubMed1995

Lipofuscin as a record of "rate of living" in an aquatic poikilotherm.

As an integral of oxidative metabolism and physiological age index, lipofuscin accumulation was used to evaluate assumptions underlying previous rejection of the rate of living theory of aging. Lipofuscin in the olfactory lobe cell mass of crayfish, Cherax quadricarinatus, was measured throughout life under a wide range of temperature regimes, using image analysis of fluorescence micrographs of brain sections. The relationship between temperature, chronological age, and rate of living, as indicated by lipofuscin accumulation rate, had a complex nonlinear three-dimensional structure, suggesting a thermal optimum, thermal mid-range metabolic compensation, and age-associated variation. The particular experimental window through which this response surface is viewed will have a profound effect on the outcome of life span experiments such as those previously used to test the rate of living theory. The results of this study further challenge assumptions leading to previous rejection of this theory.

Aging↗
PubMed1990

Early intervention in low back disability among coal miners in West Virginia: negative findings.

A major issue in the field of workers' compensation is cost containment, not only of medical costs, but of extended disability costs as well. For a 9-month period in 1985 to 1986, the West Virginia Workers' Compensation Fund tested an early intervention case management approach begun within 2 weeks after injury and found it not to be cost effective. In a controlled study of 284 reported back injuries among underground coal miners, medical costs increased with the case management intervention, although only to the extent of the added costs of the intervention, and disability costs and time lost from work did not decrease. Permanent partial disability awards, litigation rates, number of hospitalizations, and return to work were similar between both the experimental and control groups. Regression analyses of 25 factors identified factors most highly predictive of disability and medical costs, but in predicting extended disability, although the factors were 100% sensitive, they were only 43.6% specific. The case management approach was insufficient to prevent extended disability or to lower medical costs.

Absenteeism↗
PubMed1985

Disability dilemmas and rehabilitation tensions: a twentieth century inheritance.

Although disability has gradually become part of the social justice concept in Western nations since the seventeenth century, and is a current world-wide social concern, it is no way as readily definable or determinable as race, gender, age or even poverty, other issues of social justice. It remains a relative term despite efforts to contain it. The World Health Organization's definition for disability is a restriction or lack of ability to perform an activity in the manner or within the range considered normal for a human being, arising as a consequence of physiological, psychological or anatomical impairment. Under the impairment/disability paradigm, rehabilitation interventions aim for the restoration of maximum functional activity or independence. The consequences of impairment and disability can, but do not necessarily, lead to handicaps or conditions of disadvantage, the composite result of individual functional limitations and faults in physical, cultural, social, economic and political environments. Rehabilitation for handicapping conditions then implies not necessarily the restoration of maximum functional activity or independence, but the restoration of maximum social function, including work and family roles. Recent literature on disability and rehabilitation research and policy reflects the complex and expanding context, but the relativity of the concepts involved, particularly the slippage between disability and handicap, create problems of consistently determining and communicating need. For the literature, certain dilemmas are evident in determining and providing for the needs of disabled persons: self-perceived and self-defined need vs bureaucratic standards and statistical definition; resource compensation vs resource enhancement; urban vs rural needs. Closely related to these perplexing problems are tensions in rehabilitation approaches: institutional and community approaches; individual functional improvement and environmental improvement. This paper considers the dilemmas and tensions as reported, and on that basis certain policy issues are tabulated and presented.

Community Health Services↗
PubMed1985

Low-back impairment-rating practices of orthopaedic surgeons and neurosurgeons in West Virginia.

The inquiry on low-back impairment rating practices among physicians who treat or evaluate workers' compensation claimants replicates an earlier inquiry appearing in Spine by Brand and Lehmann (1983). Findings are essentially similar. Physicians consider factors other than those of physical impairment in assigning ratings, and ratings in two states are similar rather than different. The conclusion of the earlier inquiry and premise of this inquiry is that lacking widely accepted criteria for rating low-back impairment, physicians rate the disability of an individual as they perceive it. Based on findings from both inquiries, variance among ratings increases as ratings become higher. A second conclusion is that duration of time-loss disability from work before a permanent rating is made can be detrimental regarding return to work.

Back Injuries↗
PubMed1984

Intervention in work-related disability: the need for an integrated approach.

This paper looks at work-related disability in the United States as it is currently addressed according to the policies and procedures of the Social Security Disability Administration and the Workers' Compensation system. These policies and procedures proceed from a medical model that emphasizes health impairment as the fundamental cause of work-related disability. Thus physicians' evaluations of work-related impairment are the primary basis for administrative disability determinations. Increasing litigation regarding disability determinations and experience with long-term work-related disability suggest that the guiding policies are flawed. Work-related disability is as much a problem of manpower policy as it is one of personal health, but most employers and compensation programs in the United States do not yet respond to it as such. Recommended is a shift from a medical to a socioeconomic frame of reference for work-related disability that would overtly recognize regional variations in the static and dynamic factors of the economy and that would promote return to work and rehabilitation. Political intervention will be necessary. Because cultural values and social relationships are part of the problem, new research is needed in correlates of work-related disability.

Disability Evaluation↗
PubMed1983

Staff training through collaboration: the training resources center.

As fiscal resources for mental health programs dwindle, it is becoming increasingly important to preserve non-direct-service priorities such as staff development. The West Virginia Training Resources Center, a collaborative program operated by the West Virginia Department of Health and the West Virginia University department of behavioral medicine and psychiatry, addresses problems of staff training in the state mental health service system. The authors discuss the development of the center and its functions as provider of training programs, sponsor of statewide training conferences, and clearinghouse of information and expertise. They also discuss problems stemming from the increased need for continuing education for paraprofessionals, the use of outside consultants, and the relationship between academia and the health service sector.

Community Mental Health Centers↗