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Biomedical subjects

K Phelps

Publications and source records attributed to K Phelps.

11 recordsLinked to original sources
PubMed2003

Study of temperature-growth interactions of entomopathogenic fungi with potential for control of Varroa destructor (Acari: Mesostigmata) using a nonlinear model of poikilotherm development.

AIMS: To investigate the thermal biology of entomopathogenic fungi being examined as potential microbial control agents of Varroa destructor, an ectoparasite of the European honey bee Apis mellifera. METHODS AND RESULTS: Colony extension rates were measured at three temperatures (20, 30 and 35 degrees C) for 41 isolates of entomopathogenic fungi. All of the isolates grew at 20 and 30 degrees C but only 11 isolates grew at 35 degrees C. Twenty-two isolates were then selected on the basis of appreciable growth at 30-35 degrees C (the temperature range found within honey bee colonies) and/or infectivity to V. destructor, and their colony extension rates were measured at 10 temperatures (12.5-35 degrees C). This data were then fitted to Schoolfield et al. [J Theor Biol (1981)88:719-731] re-formulation of the Sharpe and DeMichele [J Theor Biol (1977)64:649-670] model of poikilotherm development. Overall, this model accounted for 87.6-93.9% of the data variance. Eleven isolates exhibited growth above 35 degrees C. The optimum temperatures for extension rate ranged from 22.9 to 31.2 degrees C. Only three isolates exhibited temperature optima above 30 degrees C. The super-optimum temperatures (temperature above the optimum at which the colony extension rate was 10% of the maximum rate) ranged from 31.9 to 43.2 degrees C. CONCLUSIONS: The thermal requirements of the isolates examined against V. destructor are well matched to the temperatures in the broodless areas of honey bee colonies, and a proportion of isolates, should also be able to function within drone brood areas. SIGNIFICANCE AND IMPACT OF THE STUDY: Potential exists for the control of V. destructor with entomopathogenic fungi in honey bee colonies. The methods employed in this study could be utilized in the selection of isolates for microbial control prior to screening for infectivity and could help in predicting the activity of a fungal control agent of V. destructor under fluctuating temperature conditions.

Acari↗
PubMed2001

Seed reserve-dependent growth responses to temperature and water potential in carrot (Daucus carota L.).

Both temperature and soil moisture vary greatly in the surface layers of the soil through which seedlings grow following germination. The work presented studied the impact of these environmental variables on post-germination carrot growth to nominal seedling emergence. The rapid pre-crook downward growth of both the hypocotyl and root was consistent with their requirement for establishment in soil drying from the surface. At all temperatures, both hypocotyl and root growth rates decreased as water stress increased and there was a very distinct temperature optimum that tended to occur at lower temperatures as water stress increased. A model based on the thermodynamics of reversible protein denaturation was adapted to include the effects of water potential in order to describe these growth rate responses. In general, the percentage of seedlings that reached the crook stage (start of upward hypocotyl growth) decreased at the extremes of the temperature range used and was progressively reduced by increasing water stress. A model was developed to describe this response based on the idea that each seedling within a population has lower and upper temperature thresholds and a water potential threshold which define the conditions within which it is able to grow. This threshold modelling approach which applies growth rates within a distribution of temperature and water potential thresholds could be used to simulate seedling growth by dividing time into suitable units.

Daucus carota↗
PubMed2001

Choosing and using services for sexual health: a qualitative study of women's views.

OBJECTIVE: To explore women's accounts of choosing and using specialist services for sexual health. METHODS: A qualitative study involving semistructured interviews with 37 women screened for Chlamydia trachomatis attending genitourinary medicine and family planning clinics in an East Midlands health authority. RESULTS: In making the decision to seek help, women act on a range of specific prompts, including lay ideas about the significance of symptoms; their own behaviour; their partner's symptoms or behaviour; contact tracing; and health promotion. Some women do not seek help specifically in relation to sexual health but are identified as being at risk of sexually transmitted infections (STIs) during routine consultations. Important influences on women's choice of services include the lay referral system, "insider" knowledge of health services, referral by health professionals, and need to have alternatives to general practice care. Women's willingness to access services is mediated by psychosocial factors such as embarrassment. They may use smear tests as a legitimate opportunity to raise questions about sexual health. Women's priorities for services are that their feelings of stigma and embarrassment are managed appropriately; that staff communicate well and are sensitive to their emotions and comfort during tests and procedures; that they are "in control" when obtaining test results; and that confidentiality is preserved. CONCLUSIONS: A detailed understanding of both lay people's response to symptoms or behaviour that indicates risk of an STI and their needs when using services should inform interventions aimed at encouraging secondary prevention of STIs.

Adolescent↗
PubMed2001

District nurse-led beds: an alternative to care at home.

Intermediate care is a key feature of the Government's plans for the development of the health service. The intermediate care scheme described here offers a district nurse-led bed (DNLB) stay in a community hospital to patients in the community who require short-term nursing help. District nurses are given the opportunity to admit patients from their community caseloads into a DNLB in a community hospital and are responsible for their admission, care and discharge. This article describes the pilot study that monitored the first 30 patients who used the DNLBs. Patients included younger people with multiple sclerosis who were admitted for respite care, but the principal beneficiaries were those aged over 65 years with chronic conditions.

Adult↗
PubMed2000

Best place of care for older people after acute and during subacute illness: a systematic review.

OBJECTIVES: To assess the evaluative research literature on the costs, quality and effectiveness of different locations of care for older patients. METHODS: A systematic review of evaluative research from 1988 using CRD4 guidelines. Twenty-five databases were searched, using processes developed specially for this review. Library OPACS, the Internet and research registers were also searched for relevant material. The final stage of the review was confined to randomised and pseudorandomised trials. Studies were selected for review by pairs of researchers working independently who then met to reach a decision. Analysis was predominantly descriptive; simple pooled odds ratios were used to explore some outcomes. RESULTS: Eighty-four papers from 45 trials were included. Firm conclusions were difficult to draw, except in relation to some outcomes for stroke units, early discharge schemes and geriatric assessment units. Few trials in this area have adequately addressed issues of patients' quality of life and costs to health services, social care providers, patients and their families. CONCLUSIONS: Despite considerable recent development of different forms of care for older patients, evidence about effectiveness and costs is weak. However, evidence is also weak for longer-standing care models. A substantial service evaluation agenda emerges from this review. This study also raises questions about the usefulness of systematic review techniques in the area of service delivery and organisation.

Acute Disease↗
PubMed1999

Tumour necrosis factor-alpha regulates expression of the CCAAT-enhancer-binding proteins (C/EBPs) alpha and beta and determines the occupation of the C/EBP site in the promoter of the insulin-responsive glucose-transporter gene in 3T3-L1 adipocytes.

We have demonstrated previously that treatment of 3T3-L1 adipocytes with tumour necrosis factor-alpha (TNF) results in a rapid (4 h) and significant (75-80%) reduction in the rate of transcription of the GLUT4 gene. Control of GLUT4 gene transcription has been suggested at least in part to reside with the CCAAT-enhancer-binding protein (C/EBP) family (alpha, beta and delta isoforms) of transcription factors. Using electrophoretic mobility shift assays, we have examined the ability of TNF to alter the occupation of the C/EBP site in the GLUT4 promoter. The data suggest that in fully differentiated adipocytes the C/EBP site is a ligand for predominantly alpha/alpha homodimers; however, after exposure to TNF, a shift in occupancy of the site occurs and the ligands become alpha/beta heterodimers and beta/beta homodimers. Partner selection in dimer formation appears to be controlled by selective translocation of the beta-isoform from the cytosol to the nucleus after exposure of the cells to TNF.

3T3 Cells↗
PubMedDate not supplied

Factors associated with emergency department utilization for nonurgent pediatric problems.

OBJECTIVE: To identify specific caretaker and utilization characteristics predictive of the use of the emergency departments (EDs) for nonurgent reasons. Each year more than 20 million children in the United States seek medical care in EDs. Between one third and one half of these visits are for nonurgent reasons. DESIGN: A descriptive study conducted during a 6-month period. SETTING: Two urban hospital EDs. MEASURE: A questionnaire was designed to elicit information about specific caretaker characteristics and their reasons for using the ED for their child's nonurgent medical care. SUBJECTS: Two hundred caretakers and children brought to the ED for nonacute medical care. Caretakers in this study included mothers (82%) with a mean age of 30 years, single caretakers (70%), and unemployed caretakers (60%). The average age of the children was 6.2 years. RESULTS: Most caretakers (92%) reported having a continuity physician for their children. Caretakers who reported being taken to the ED when they were children (P<.002) and those with Medicaid insurance (P<.001) were more likely to view the ED as the usual site of care. Being a single parent was a predictor for nonurgent visits (P<.05). CONCLUSIONS: Predicting which caretakers are at risk for using the ED for nonurgent care when their children are sick provides the primary care physician a means of identifying specific patients who may benefit from interventions designed to promote a more cost-effective approach to using medical resources. Arch Fam Med. 2000;9:1086-1092

Child↗