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Biomedical subjects

J K Olson

Publications and source records attributed to J K Olson.

At least 55 records · Page 3Linked to original sources
PubMed1996

Insecticide susceptibility of Aedes aegypti and Aedes albopictus in the Lower Rio Grande Valley of Texas and Mexico.

In response to a potential dengue fever outbreak in south Texas during 1995, the susceptibilities of Aedes aegypti and Aedes albopictus to commonly used mosquito adulticides were assessed. Larvae collected from the Lower Rio Grande Valley of Texas and Mexico were reared to adults and tested against susceptible laboratory strains at Texas A&M University. Resistance ratios at both the LC50 and LC95 rates were all less than 10, indicating that adult populations of both species are still susceptible to malathion, chlorpyrifos, resmethrin, and permethrin.

Aedes↗
PubMed1995

Relationships between nurse-expressed empathy, patient-perceived empathy and patient distress.

It is increasingly important that nursing care be associated with measurable patient outcomes. A correlational study examined relationships between nurse-expressed empathy and two patient outcomes: patient perceived empathy and patient distress. Subjects (N = 140) were randomly selected from RNs and patients on medical and surgical units in two urban, acute care hospitals. Nurse-subjects (N = 70) completed two measures of nurse-expressed empathy: the Behavioral Test of Interpersonal Skills and the Staff-Patient Interaction Response Scale. Patient-subjects (N = 70) completed the Profile of Mood States, the Multiple Affect Adjective Checklist, and the Barrett-Lennard Relationship Inventory. Findings indicated a negative relationship (r = .71, p < .001) between a set of empathy variables and a set of patient distress variables and a positive relationship between nurse-expressed and patient perceived empathy (r = .37-.47, p < .05). This study is one of the first to link behavioral measures of nurse empathy to patient outcomes.

Adult↗
PubMed1995

Content analysis of nonprofessional caregiver-patient interactions in long-term care facilities.

A content analysis of tape-recorded, nonprofessional caregiver-patient interactions was undertaken to determine the nature and content of conversation during the provision of morning care in long-term care facilities. Caregivers initiated and directed the majority of topics, generally keeping the patient as the focus of the interaction. Patients and caregivers initiated different types of topics, with caregivers being more interested in care activities, social conversation, care environment, and patients' physical health. Patients introduced topics of a more personal nature: social systems, reminiscences, and hopes and plans. It was concluded that nonprofessional caregivers require communication skills training. Questions were raised about the effects of caregiver communication on patients in long-term care facilities.

Adult↗
PubMed1994

Culekinin depolarizing peptide: a mosquito leucokinin-like peptide that influences insect Malpighian tubule ion transport.

A peptide termed culekinin depolarizing peptide (CDP) was isolated from approximately 1.2 million mosquitos (94% Culex salinarius). The peptide was isolated on the basis of a rapid myotropic assay that utilized a hindgut preparation from Leucophaea maderae and a transepithelial voltage assay that used mosquito Malpighian tubules from Aedes aegypti. A 15% trifluoroacetic acid extraction from the mosquitos, two solid phase extraction steps, and six HPLC steps resulted in the isolation of 9.7 nmol of CDP. This value corresponds to approximately 8 fmol/mosquito. Edman degradation indicated the following sequence for CDP: Asn-Pro-Phe-His-Ser-Trp-Gly-NH2. The sequence was confirmed as the suspected C-terminal amide form of the peptide, since native and synthetic CDP had identical chemical and biological properties. CDP is a member of the leucokinin family of neuropeptides. The leucokinins have been found in three other insect species (Leucophaea maderae, Acheta domesticus and Locusta migratoria) where these peptides were isolated by their myotropic properties alone. CDP shares a C-terminal sequence homology (i.e., Phe-X-Ser-Trp-Gly-NH2) with the rest of the leucokinins. CDP corresponds to the strongest tubule depolarizing activity in the C. salinarius extract. These findings agree with previous structure-activity studies that suggest that mosquitos would contain a leucokinin-like factor that had Phe-His-Ser-Trp-Gly-NH2 as the C-terminal pentapeptide. This is the first leucokinin isolated from blood feeding or holometabolous insects.

Aedes↗
PubMed1994

Effect of a lunar eclipse on the flight activity of mosquitoes in the upper Gulf Coast of Texas.

Adult mosquito flight activity was monitored at a coastal marshland site in Chambers County, TX, before, during, and after a total eclipse of the moon on August 16, 1989. A vehicle-mounted mobile interceptor trap and a stationary, dry ice-baited CDC miniature light trap were used in this monitoring effort. Aedes sollicitans, Anopheles crucians, Culex salinarius, and Psorophora columbiae were mosquito species most abundantly represented in collections made by both traps during the 12-h study period. The numbers of each of these species collected by the vehicle-mounted trap decreased during the lunar eclipse and increased when the full moon was exposed. Collections of these same species by the light trap increased during the lunar eclipse and decreased when the full moon was exposed.

Aedes↗
PubMed1994

Effects of a natural marsh fire on larval populations of Culex Salinarius in east Texas.

A natural marsh fire caused by lightning suppressed Culex salinarius larval populations for 2 months following the fire. Removal of emergent vegetation and higher water temperatures rendered burned-area pools unsuitable either for larval development or deposition of eggs or both. With a drop in seasonal ambient temperature and a regrowth of emergent vegetation, the burned areas returned to being suitable larval development sites for Culex salinarius. no differences in water salinity or pH were observed between burned and unburned locations.

Animals↗
PubMed1992

Efficacy of Bacillus thuringiensis var. israelensis against larvae of the southern buffalo gnat, Cnephia pecuarum (Diptera: Simuliidae), and the influence of water temperature.

Susceptibility of southern buffalo gnat larvae to Bacillus thuringiensis var. israelensis (B.t.i.) was studied during 1986-88. Tests were conducted using Vectobac 12AS in a mini-gutter aquatic bioassay system. Mini-gutter tests using a 4.5 ppm B.t.i. concentration and a 10 min exposure period confirmed a positive correlation between water temperature and B.t.i. effectiveness. Significantly lower larval mortality occurred as water temperature decreased below 9 degrees C, indicating that proper timing of B.t.i. application is essential to maximize larval control. Even with this temperature limitation, larval control using B.t.i. should provide an economically effective means of preventing outbreaks of the southern buffalo gnat.

Animals↗
PubMed1990

Analysis of the gut contents of naiads of Enallagma civile (Odonata: Coenagrionidae) from a Texas pond.

Foregut contents of naiads of the damselfly species, Enallagma civile, collected from a permanent pond, were analyzed to determine the natural prey for immatures of this species. The analyses revealed the naiads containing prey had fed predominantly on chironomid larvae. Corixid, cladoceran, ostracod and aquatic mite remains were found in some of the naiad specimens examined. However, no remains of mosquito larvae were detected in any of the specimens, even though mosquito larvae were observed as being continuously present in the pond sites where the naiad specimens were collected.

Animals↗
PubMed1989

Use of aerial color infrared photography as a survey technique for Psorophora columbiae oviposition habitats in Texas ricelands.

This study investigated the possibility of using aerial color infrared (CIR) photography as a survey technique for egg populations of Psorophora columbiae within a riceland agroecosystem. To accomplish this, eight photographic missions were flown over study fields during a variety of seasons and at various altitudes. Assessment of resulting photographic data indicates features reported in the literature as being attractive for oviposition by Ps. columbiae (i.e., rice field levees, tire tracks, ditches and low areas) can be readily detected on aerial CIR photographs. Features associated with Ps. columbiae oviposition sites were easily visible on photographs at scales as small as 1:42,000.

Aircraft↗
PubMed1989

Conceptual model for the use of aerial color infrared photography by mosquito control districts as a survey technique for Psorophora columbiae oviposition habitats in Texas ricelands.

Two photographic missions per year are recommended to provide information on land-use and mosquito oviposition habitats. A winter mission, following a rain, will-provide a view of low areas within fields which may be obscured by summer vegetation. A summer mission will provide current land-use and crop distribution information and may show plant stress conditions due to excessive soil moisture. An aerial color infrared photographic survey with directed ground verification should result in a substantial savings in cost and increased efficiency in surveillance of mosquito producing habitats over ground survey techniques currently employed by mosquito control districts.

Animals↗
PubMed1989

Effects of sublethal dosages of insecticides on Culex quinquefasciatus.

Groups of Culex quinquefasciatus were exposed as fourth instar larvae to sublethal concentrations (0.1 LC50 and LC50) of malathion, methoprene, propoxur or resmethrin. Females exposed as larvae to an LC50 level of methoprene had reduced wing length and longevity. Egg production was reduced by 50% and 39% in those mosquitoes exposed to LC50 levels of malathion or methoprene, respectively. In contrast, egg production and egg raft size increased following treatment with 0.1 LC50 levels of malathion or methoprene. Females exposed as larvae to methoprene laid 30% fewer eggs per raft, and egg hatching decreased 36% compared with controls. Females exposed as larvae to LC50 levels of malathion or methoprene laid shorter eggs than controls. The proportion of females in the adult population was reduced following exposure to either propoxur or resmethrin, and increased following exposure to malathion. Time to pupation and time of emergence of the adult populations were increased following exposure to most of the insecticidal treatments. These results indicated that a single, sublethal exposure to certain insecticides had a significant effect on mosquito reproduction.

Animals↗
PubMed1987

Effects of a training model on active listening skills of post-RN students.

This study investigated the effects of a training module on the active listening skills of non-degree registered nurses. Active listening skills were defined as understanding what another person is saying and feeling and then communicating this understanding of his thoughts and feelings back to him. The sample consisted of 26 post-diploma RNs registered in the first year of a baccalaureate degree nursing program. Pretraining and posttraining data were collected when subjects verbally responded to two portions of the Behavioral Test of Interpersonal Skills for Health Professionals (BTIS). Subjects were audiotaped while responding and tapes were scored using BTIS guidelines. Paired t-tests were used to determine differences between pretraining and posttraining scores. Active listening scores increased significantly (p less than .0005) while attempts to suppress or discount speakers' feelings decreased significantly (p less than .005). A six-hour training session significantly increased active listening skills.

Adult↗
PubMed1987

The public's view of mosquito problems in an organized control district.

Mosquito control programs provide abatement services to residents of urban, suburban and rural areas. The differing perceptions of these programs by residents of the Jefferson County Mosquito Control District (Texas) are examined using a mail survey. Mosquito problems start occurring earlier in the year for urban residents. The average number of bites per hour per night was 11. Rural residents used more self-administered control methods and incurred greater expenditures for these efforts than other residents. A majority of respondents recognized the effectiveness of the mosquito control district's current abatement efforts, but 56% supported greater use of nonchemical control methods. The study methods are expected to be useful in other areas to address similar problems.

Adult↗
PubMed1987

Oviposition habitats of Psorophora columbiae in soybean fields of a Texas riceland agroecosystem.

Soil samples were collected over a 21/2-year period from microhabitats in fields planted to soybeans in Chambers County, TX, to study the oviposition behavior of Psorophora columbiae. An analysis of egg collection data gathered from the processing of 1,098 soil samples suggested that, during wet years, Ps. columbiae eggs tend to be scattered throughout soybean fields. During dry years, a greater abundance of eggs occur in the low areas of these types of fields. The data also suggested that oviposition by Ps. columbiae is concentrated in soil near the base of soybean plants rather than in open furrows between the rows of plants.

Agriculture↗
PubMed1987

An economic assessment of the benefits of mosquito abatement in an organized mosquito control district.

A case study application of contingent valuation to the measurement of mosquito program benefits is presented. Annual program benefits in Jefferson County, TX are estimated to exceed costs by 1.8 times. Mean household benefits are $22.44 for owners and $18.96 for renters. Using ordinary least squares procedures these household benefits were found to be related to household socioeconomic characteristics, effectiveness of control efforts and environmental concerns.

Cost-Benefit Analysis↗