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Biomedical subjects

J F Campbell

Publications and source records attributed to J F Campbell.

At least 19 recordsLinked to original sources
PubMed2007

Responses of the entomopathogenic nematode, Steinernema riobrave to its insect hosts, Galleria mellonella and Tenebrio molitor.

Potential hosts for infective juveniles of entomopathogenic nematodes can vary considerably in quality based on the characteristics of the host species/stage, physiological status (e.g. stress, feeding on toxins), and infection status (heterospecific or conspecific infection). In this study, we investigated responses of the entomopathogenic nematode Steinernema riobrave to hosts (Galleria mellonella or Tenebrio molitor) that were previously parasitized with conspecifics or injected with the nematode-symbiotic bacterium, Xenorhabdus sp., to determine if there is a preference for previously parasitized/injected hosts and when this preference might occur. In no-choice bioassays, the number of juveniles infecting both host species decreased with increasing time post-infection. However, infective juveniles continued to infect previously parasitized hosts up to 72 h. Significant preference was exhibited by S. riobrave for 24 h post-infection G. mellonella larvae over uninfected, and by 24 h post-injection G. mellonella larvae over 48 h post-injection larvae. No significant preference was exhibited by S. riobrave for T. molitor hosts previously parasitized with conspecifics or those injected with bacteria in any treatment combination. Such preference for, or continued infection of parasitized insects, has the potential to impact nematode efficacy.

Animals↗
PubMed2006

Attraction behaviour of three entomopathogenic nematode species towards infected and uninfected hosts.

Entomopathogenic nematode infective juveniles are likely to encounter both uninfected and infected insects and host quality depends on the stage of the infection. We hypothesized that nematode response to infected hosts will change over the course of an infection. Here, we tested this hypothesis by focusing on the influence of host infection status on long-range attraction to host volatile cues. The attraction response of 3 nematode species (Steinernema carpocapsae, S. glaseri and S. riobrave) with different foraging strategies to infected and uninfected insects (Galleria mellonella and Tenebrio molitor) was tested at 24 h intervals from start of infection to emergence of infective juveniles from depleted host. As expected, based on their foraging strategies, S. carpocapsae was not very responsive to hosts, S. glaseri was highly responsive and S. riobrave was intermediate. Generally, the level of attraction did not change with time after infection and was similar between infected and uninfected hosts. An exception was S. glaseri infected T. molitor, which tended to be less attractive to S. glaseri than uninfected hosts. These results suggest that any influence of host infection status on infection behaviour is occurring at subsequent steps in the host-infection process than host attraction, or involves non-volatile cues.

Animals↗
PubMed2006

Effect of temperature, exposure interval, and depth of diatomaceous earth treatment on distribution, mortality, and progeny production of lesser grain borer (Coleoptera: Bostrichidae) in stored wheat.

Diatomaceous earth (DE) can be used as a surface treatment in stored wheat Triticum aestivum (L.) to control pest infestations. However, it is not known how the thickness of the DE-treated wheat layer or grain temperature impact effectiveness. Therefore, we conducted an experiment in growth chambers to assess the effect of different surface layers of hard winter wheat combined with DE on spatial distribution, adult survival, and progeny production of lesser grain borer, Rhyzopertha dominica (F.), and to determine whether temperature and exposure interval modified this effect. When adult lesser grain borers were released in experimental towers containing untreated wheat or wheat admixed with DE to a surface layer depth of 15.2, 22.9, or 30.5 cm, they were able to penetrate all DE layers and oviposit in the untreated wheat below. However, survival was significantly reduced in adults exposed to DE. Survival decreased both with increasing depth of the DE-treated wheat and with exposure interval. Temperature had no effect on adult survival, but significantly more progeny were produced at 32 than at 27 degrees C. Progeny production was inversely correlated with the depth of the DE-treated layer. Vertical distribution patterns of parental beetles were not significantly different among treatments or exposure intervals; however, more insects were found at greater depths at 32 than at 27 degrees C. The F1 production was reduced by 22% at the thickest DE-treated layer. However, we conclude that this level of survival could leave a residual population of lesser grain borers that would probably be above an allowable threshold for insect damage.

Animals↗
PubMed2004

Distribution and dispersal behavior of Trogoderma variabile and Plodia interpunctella outside a food processing plant.

The distribution and dispersal distances of insects outside of food processing and storage facilities potentially have an important influence on the population dynamics and spatial distribution of insects inside facilities. In this study, Trogoderma variabile Ballion and Plodia interpunctella (Hübner) sex pheromone-baited trap captures outside and inside a food processing facility were measured, the relationship between trap captures outside and inside the facility was evaluated, and the dispersal ability of the males of these species was assessed using self-mark-recapture stations. T. variabile and P. interpunctella males were captured in high numbers outside the food facility. The two species differed in their spatial distribution around the facility, with T. variabile being more closely associated with the proximity of the building, but most likely originating from sources outside the building. For marked T. variabile, the average recapture distance was 75 m (range 21-508 m) and for marked P. interpunctella the average recapture distance was 135.6 m (range 21-276 m). In an immigration/emigration experiment, three T. variabile marked outside were recaptured inside, but no T. variabile marked inside were recaptured outside and no marked P. interpunctella were recaptured in either location. The potential for outside populations to influence inside populations has implications for the effectiveness of different management and monitoring tools.

Animals↗
PubMed2003

Patch exploitation by female red flour beetles, Tribolium castaneum.

The red flour beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) has had a long association with human stored food and can be a major pest in anthropogenic structures used for the processing and storage of grain-based products. Anthropogenic structures are fragmented landscapes characterized by spatially and temporally patchy resources. Here we investigate the ability of female T. castaneum to evaluate the quality of small patches of food and to adjust the number of eggs they lay per patch (i.e., clutch size) to maximize fitness gains. In multiple choice, paired choice and no choice experiments females tended to lay more eggs in larger amounts of flour. The number of eggs that they lay in a patch of flour was consistent with that predicted to optimize production of adults from that patch (i.e., the 'Lack' clutch size). Progeny size was only significantly impacted in the smallest patch sizes.

Animals↗
PubMed2002

Monitoring stored-product pests in food processing plants with pheromone trapping, contour mapping, and mark-recapture.

Distribution and movement patterns of several species of stored-product pests in a food processing plant were investigated. The objectives of this study were to determine the temporal and spatial variation in abundance of stored-product pests using pheromone traps; assess the effectiveness of trap type, location, and number on monitoring insect populations; and to evaluate the nature of pheromone trap capture hot spots by measuring patterns of insect movement. We determined that the distributions of Trogoderma variabile Ballion, Lasioderina serricorne (F.), Tribolium castaneum (Herbst), and Plodia interpunctella (Hübner) within the facility were typically clumped and that foci of high trap captures, based on visual observation of contour maps, varied among species and over time. Trap type and location influenced the number of T. variabile captured: traps on the floor and along walls captured more individuals than hanging traps and traps next to support pillars. T. variabile was the predominant insect pest at this facility and from mark-recapture studies, we found that individual beetles moved across multiple floors in the facility and from 7 to 216 m though the warehouse.

Animals↗
PubMed2002

Mechanisms underlying sawtoothed grain beetle (Oryzaephilus surinamensis [L.]) (Coleoptera: Silvanidae) infestation of consumer food packaging materials.

The sawtoothed grain beetle, Oryzaephilus surinamensis (L.), is an extremely destructive pest of packaged consumer food products. The beetle is not believed to chew directly through packaging materials, but to use openings or flaws in damaged or improperly sealed packages to gain entry. We investigated the behavioral mechanisms by which the sawtoothed grain beetle infests packages with flaws. Significantly more sawtoothed grain beetles infested consumer food packages that had been punctured with 0.4 mm diameter holes, to simulate packaging flaws that preclude adults, than when packages had no flaws. In a test arena, females laid more eggs into or near the hole in a plastic packaging film, when they were able to contact the food through the hole than when they could not contact the food. First instar larvae placed either 1 mm or 1 cm away entered holes when food was present, indicating that packages could become infested if eggs were laid near holes. In the absence of food, neither adults nor larvae responded to holes. This study has shown the importance of sound packaging in preventing insect infestation.

Animals↗
PubMed2001

Phylogeny of Steinernema travassos, 1927 (Cephalobina: Steinernematidae) inferred from ribosomal DNA sequences and morphological characters.

Entomopathogenic nematodes in Steinernema, together with their symbiont bacteria Xenorhabdus, are obligate and lethal parasites of insects that can provide effective biological control of some important lepidopteran, dipteran, and coleopteran pests of commercial crops. Phylogenetic relationships among 21 Steinernema species were estimated using 28S ribosomal DNA (rDNA) sequences and morphological characters. Sequences of the rDNA internal transcribed spacers were obtained to provide additional molecular characters to resolve relationships among Steinernema carpocapsae, Steinernema scapterisci, Steinernema siamkavai, and Steinernema monticolum. Four equally parsimonious trees resulted from combined analysis of 28S sequences and 22 morphological characters. Clades inferred from analyses of molecular sequences and combined datasets were primarily reliably supported as assessed by bootstrap resampling, whereas those inferred from morphological data alone were not. Although partially consistent with some traditional expectations and previous phylogenetic studies, the hypotheses inferred from molecular evidence, and those from combined analysis of morphological and molecular data, provide a new and comprehensive framework for evaluating character evolution of steinernematids. Interpretation of morphological character evolution on 6 trees inferred from sequence data and combined evidence suggests that many structural features of these nematodes are highly homoplastic, and that some structures previously used to hypothesize relationships represent ancestral character states.

Animals↗
PubMed1999

Are there temporarily non-infectious dauer stages in entomopathogenic nematode populations: a test of the phased infectivity hypothesis.

Many studies of entomopathogenic nematodes (Heterorhabditidae and Steinernematidae) have reported that only a small proportion (typically < 40%) of infective stages (dauers), even under apparently ideal conditions, actually infect a host. The 'phased infectivity hypothesis' is most frequently invoked to explain this pattern of low infection with entomopathogenic nematodes. It proposes that at a given point in time not all individuals are infectious i.e. infectiousness is delayed in some individuals. We tested experimentally several predictions based on this hypothesis. Specifically, if phased infectivity occurs, we should be able to expose dauers to increasing numbers of potential hosts until dauers no longer infect and still be able to recover viable dauers. These recovered dauers which did not infect should be infectious at some later point in time. However, our results do not support the phased infectivity hypothesis for 3 species of Steinernema: most dauers could be recovered in one sampling round when provided with sufficient suitable hosts. In contrast, Heterorhabditis bacteriophora frequently did not infect all available hosts, and infectious dauers were recovered in subsequent sampling rounds. This result is more consistent with the phased infectivity hypotheses, but further research is needed before we can be more confident in the hypothesis. For all species tested, the number of available hosts influenced population levels of nematode infectivity. This suggests that the infection status of hosts can influence whether a dauer infects. Our results indicate that phased infectivity is not a common phenomenon in entomopathogenic nematode dauers, despite the widespread acceptance of this hypothesis.

Animals↗
PubMed1996

Entomopathogenic nematode (Heterorhabditidae and Steinernematidae) spatial distribution in turfgrass.

Understanding the temporal and spatial distribution of entomopathogenic nematodes is essential for determining the role of these insect parasites in soil communities and ultimately for their use in suppression of pest insect populations. We measured the vertical and horizontal distribution of endemic populations of entomopathogenic nematodes (Steinernema carpocapsae and Heterorhabditis bacteriophora) in turfgrass. Vertical distribution was determined by taking soil cores every 3 h from 05.00 to 23.00 h, over 4 days, and dividing the cores into 8, 1 cm deep sections. Steinernema carpocapsae was recovered primarily near the soil surface: 50% of positive sections were recovered in the thatch or first 1 cm of soil. S. carpocapsae recovery was lower during the middle of the day and none were recovered in the upper section. H. bacteriophora was recovered uniformly throughout the top 8 cm of soil and its vertical distribution did not change over the course of the day. Horizontal distribution was measured as the number of nematodes recovered from cores taken from 12 randomly selected 0.3 x 0.8 m sections from within four 15.3 x 15.3 m plots. Samples were collected biweekly over a 9-month period. H. bacteriophora had a patchier distribution than S. carpocapsae and both nematode species had more patchy distributions then their potential hosts. Our results support the hypothesis that these two species of nematode utilize different foraging strategies; S. carpocapsae primarily a surface adapted ambusher and H. bacteriophora as a cruise forager.

Animals↗
PubMed1993

Pneumococcal polysaccharide vaccine efficacy. An evaluation of current recommendations.

OBJECTIVE: To determine pneumococcal polysaccharide vaccine efficacy in selected populations at risk for serious pneumococcal infection for whom vaccination is currently recommended and to assess duration of protection after vaccination. DESIGN: Vaccine efficacy was estimated using indirect cohort analysis to compare the proportion of pneumococcal infections caused by serotypes included in the vaccines of vaccinated and unvaccinated persons who were identified during 14 years of national surveillance. SETTING: Hospital laboratories in the United States that submitted pneumococcal isolates to the Centers for Disease Control and Prevention between May 1978 and April 1992. PARTICIPANTS: A total of 2837 persons older than 5 years who had pneumococcus isolated from blood or cerebrospinal fluid. RESULTS: Overall efficacy for preventing infection caused by serotypes included in the vaccine was 57% (95% confidence interval [CI], 45% to 66%). Efficacy among persons with diabetes mellitus was 84% (95% CI, 50% to 95%); with coronary vascular disease, 73% (95% CI, 23% to 90%); with congestive heart failure, 69% (95% CI, 17% to 88%); with chronic pulmonary diseases, 65% (95% CI, 26% to 83%); and with anatomic asplenia, 77% (95% CI, 14% to 95%). Efficacy was not documented for patients with alcoholism or cirrhosis, sickle cell disease, chronic renal failure, lymphoma, leukemia, or multiple myeloma, although sample sizes were small for these groups. Efficacy for immunocompetent persons older than 65 years was 75% (95% CI, 57% to 85%). Efficacy did not decline with increasing interval after vaccination: 5 to 8 years after vaccination it was 71% (95% CI, 24% to 89%), and 9 years or more after vaccination it was 80% (95% CI, 16% to 95%). CONCLUSIONS: Intensified efforts to improve pneumococcal vaccine coverage among certain populations for whom vaccination is currently recommended is indicated, but universal revaccination is not warranted at this time.

Adolescent↗
PubMed1992

The effects of aerobic exercise on migraine.

A six-week cardiovascular exercise program was provided to 11 subjects classified as experiencing classical migraines, while 9 similarly-classified subjects served as waiting-list controls. Measures included the Canadian Aerobic Fitness test, a headache diary to record the Frequency, Intensity, and Duration of migraine episodes and the Pain-Severity, Affective-Distress, and Support scales of the West Haven-Yale Multidimensional Pain Inventory (MPI). Measures were taken on both treatment and control subjects before, mid-way through, and upon termination of the first aerobic program, as well as after a two week follow-up. The aerobic classes were effective in significantly improving cardiovascular fitness. Pain Severity decreased significantly for those receiving aerobic training, who also showed (nonsignificant) trends, over the measurement periods, toward reductions in Affective Distress as well as the Frequency, Intensity and Duration of migraines, but these trends failed to reach statistical significance. Control subjects demonstrated no systematic changes in any of the dependent measures. These results suggest possible long-term benefits of aerobic fitness in the management of classical migraines.

Adult↗
PubMed1992

Quantitative differences between male and female Hawaiian early adolescents in their primary factors of personality.

Empirically examined were the quantitative differences between 349 female and 230 male Hawaiian early adolescents (M age = 12.1 yr.) in the seven primary personality factors previously found: Super Ego, Ego Strength, Anxiety, Dependence vs Independence, Social Activity vs Shyness, Dominance vs Submission, and Masculinity vs Femininity. A multivariate analysis that examined the difference on each factor while statistically controlling for differences in the others indicated female Hawaiian early adolescents are higher on Dependence and Social Activity and lower on Super Ego and Masculinity scales. In contrast, a univariate analysis which did not statistically control for differences in other factors, although it correctly identified three differences, did not indicate one difference and falsely indicated three. Besides accurately indicating personality differences between Hawaiian early adolescent boys and girls, the research indicates the importance of multivariate analyses of differences between the sexes in further research.

Adolescent↗
PubMed1991

Culture-confirmed pneumonia due to Chlamydia pneumoniae.

Diagnosis of infection caused by Chlamydia pneumoniae, a newly recognized respiratory pathogen, has proved difficult. Between July 1987 and April 1988, culture and serologic tests for C. pneumoniae were done on specimens from 49 patients with pneumonia seen at an Atlanta hospital emergency room. Cultures from 3 patients (6%) grew C. pneumoniae. Genus-specific Chlamydia complement fixation titers and microimmunofluorescence titers for C. pneumoniae were suggestive of acute infection in all 3 culture-positive patients. Three other patients had evidence of acute disease by published criteria for antibody titers. Most studies of C. pneumonia have not had culture-proven cases; the 6% rate of positive cultures in this study support the role of C. pneumoniae as a cause of pneumonia. More widespread availability of simplified culture systems for C. pneumoniae is needed. Caution should be used when interpreting serologic tests in the absence of culture confirmation.

Adolescent↗
PubMed1991

The primary personality factors of Hawaiian, middle adolescents.

To determine whether the primary personality factors of Hawaiian, middle adolescents were the same as those Cattell postulated in 1970, for adolescents on the mainland of the United States, and in 1974 for adolescents in Germany, a personality questionnaire representing those factors completed by 694 Hawaiian, middle adolescents (M age = 15.9 yr.) was factor analyzed. Despite the analysis adhering closely to the recommendations of Cattell stated in 1973 and 1978, the eight factors derived are not the set of primary factors postulated for the other populations. Six of them do appear to be, however, primary factors within a set of seven reported in 1988 for a younger population of Hawaiian, early adolescents. In addition, these six factors also appear to be similar to the major constructs in the psychoanalytic theories of Freud and Horney.

Adolescent↗
PubMed1989

Invasive pneumococcal disease in an Alaska native population, 1980 through 1986.

From 1980 through 1986, one hundred fourteen Alaska Native patients from the Yukon-Kuskokwim Delta had community-acquired invasive pneumococcal disease confirmed by isolates of Streptococcus pneumoniae from normally sterile body sites. The annual bacteremia rates per 100,000 persons were 105 cases for all ages, 1195 cases for infants under 2 years of age, and 130 cases for adults over 59 years of age. These were six to 34 times higher than rates reported for other US populations. The most common underlying conditions in infants diagnosed before 24 months of age were previously diagnosed anemia and pneumonia, while alcoholism and anemia were most common in adults. The case-fatality rate for infants under 2 years of age was 3.2%, and the case-fatality rate for adults over 59 years of age was 30%. Serotyping of more than half the isolates identified 96% of these isolates to be present in the currently available pneumococcal polysaccharide vaccine. The pneumococcal disease rates reported herein are likely to be underestimates since most diseases that occur in this region are treated at the village level without laboratory confirmation.

Adolescent↗
PubMed1989

Pneumococcal bacteremia in Hawaii: initial findings of a pneumococcal disease prevention project.

The Hawaii Department of Health (DOH) recently established a pneumococcal disease initiative to determine the scope of serious pneumococcal disease in residents of Hawaii and to investigate methods of increasing vaccine utilization in the State. The initial phase of the project involved a review of pneumococcal bacteremia at all 38 microbiology laboratories in Hawaii during 1986 and 1987. Two hundred twenty-two residents with bacteremia were identified. Eighty-six percent of adults had pneumonia as the primary source of bacteremia. In children greater than 5 years old, pneumonia was present in 24%, otitis media in 35%, and meningitis in 11%. Bacteremia with no apparent focus of infection was found in 30% of children. The overall annual incidence of pneumococcal bacteremia was 9/10(5) population. Rates were highest in children greater than 2 years old (103/10(5] and persons greater than or equal to 65 years old (22/10(5]. These are similar to rates reported from other populations in the United States during the 1970s and early 1980s, but are less than those detected in 2 more recent population-based studies. The overall case-fatality rate in our study was relatively low (16%); however, 35% of persons greater than or equal to 65 years old died. A record of previous pneumococcal vaccination was found in the medical records of only 2 (1%) patients. Our study confirms that pneumococcal bacteremia causes significant morbidity and mortality among elderly residents of Hawaii and suggests that vaccine coverage is very low among this high-risk population. Phase 2 of the initiative included surveys of Hawaii physicians and the public to ascertain attitudes toward pneumococcal immunization.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗