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Biomedical subjects

J A Johnson

Publications and source records attributed to J A Johnson.

At least 19 recordsLinked to original sources
PubMed2007

Do radiographic indices of distal radius fracture reduction predict outcomes in older adults receiving conservative treatment?

AIM: To investigate whether radiographic deformities suggesting inadequate reduction would be associated with adverse clinical outcomes. MATERIALS AND METHODS: Consecutive patients over 50 years of age (n=74) with non-operatively managed distal radius fractures were enrolled in a prospective cohort study. They had radiographs at cast removal ( approximately 6 weeks) and completed DASH (Disabilities of the Arm, Shoulder and Hand), SF-12 (health-related quality of life), and satisfaction surveys 6-months post-fracture. A reference-standard musculoskeletal radiologist, blinded to outcomes status, measured palmar (dorsal) tilt, radial angle, radial height, ulnar height, and intra-articular step and gap. Radiographic indices were correlated to each other and to the various patient-reported outcomes in univariate and multivariate regression analyses. DASH score was the primary study outcome. RESULTS: Of the cohort studied (n=74, mean age 68.5 years, primarily white women), 71% had at least one "unacceptable" radiographic deformity by traditional criteria. Acceptable reduction varied from 60-99% depending on which single index was reported, and 44% of patients had more than two indices reported as unacceptable. Despite these radiographic findings, 6-months post-reduction, self-reported disability was low (DASH=24+/-17), health-related quality of life was near normal, and 72% were satisfied with their care. No radiographic index of wrist deformity (alone or in combination) was significantly correlated to any of the patient-reported outcomes. CONCLUSION: Self-reported outcomes in older adults with conservatively managed wrist fractures were not related to the "acceptability" of radiographic fracture reduction. The proportion of acceptable reductions varied by 40% depending on which index was reported. Consequently, detailed reporting of these indices in older adults with distal radius fracture may be inefficient or perhaps even unnecessary.

Aged↗
PubMed2006

Persistence, reproducibility, and cost-effectiveness of an intervention to improve the quality of osteoporosis care after a fracture of the wrist: results of a controlled trial.

INTRODUCTION: Older patients with fragility fractures are not commonly tested or treated for osteoporosis. Compared to usual care, a previously reported intervention led to 30% absolute increases in osteoporosis treatment within 6 months of wrist fracture. Our objective was to examine longer-term outcomes, reproducibility, and cost-effectiveness of this intervention. METHODS: We conducted an extended analysis of a non-randomized controlled trial with blinded ascertainment of outcomes that compared a multifaceted intervention to usual care controls. Patients >50 years with a wrist fracture treated in two Emergency Departments in the province of Alberta, Canada were included; those already treated for osteoporosis were excluded. Overall, 102 patients participated in this study (55 intervention and 47 controls; median age: 66 years; 78% were women). The interventions consisted of faxed physician reminders that contained osteoporosis treatment guidelines endorsed by opinion leaders and patient counseling. Controls received usual care; at 6-months post-fracture, when the original trial was completed, all controls were crossed-over to intervention. The main outcomes were rates of osteoporosis testing and treatment within 6 months (original study) and 1 year (delayed intervention) of fracture, and 1-year persistence with treatments started. From the perspective of the healthcare payer, the cost-effectiveness (using a Markov decision-analytic model) of the intervention was compared with usual care over a lifetime horizon. RESULTS: Overall, 40% of the intervention patients (vs. 10% of the controls) started treatment within 6 months post-fracture, and 82% (95%CI: 67-96%) had persisted with it at 1-year post-fracture. Delaying the intervention to controls for 6 months still led to equivalent rates of bone mineral density (BMD) testing (64 vs. 60% in the original study; p = 0.72) and osteoporosis treatment (43 vs. 40%; p = 0.77) as previously reported. Compared with usual care, the intervention strategy was dominant - per patient, it led to a $13 Canadian (U.S. $9) cost savings and a gain of 0.012 quality-adjusted life years. Base-case results were most sensitive to assumptions about treatment cost; for example, a 50% increase in the price of osteoporosis medication led to an incremental cost-effectiveness ratio of $24,250 Canadian (U.S. $17,218) per quality-adjusted life year gained. CONCLUSIONS: A pragmatic intervention directed at patients and physicians led to substantial improvements in osteoporosis treatment, even when delivered 6-months post-fracture. From the healthcare payer's perspective, the intervention appears to have led to both cost-savings and gains in life expectancy.

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PubMed2006

Cross-sectional validity of a modified Edmonton symptom assessment system in dialysis patients: a simple assessment of symptom burden.

Subjective symptom assessment should be a fundamental component of health-related quality of life (HRQL) assessment in end-stage renal disease (ESRD). Unfortunately, no symptom checklist has established reliability or validity in ESRD. We report the validation of a modified Edmonton Symptom Assessment System (ESAS) in 507 dialysis patients who concurrently completed the Kidney Dialysis Quality of Life-Short Form (KDQOL-SF) questionnaire. The ESAS demonstrated a mean of 7.5+/-2.5 symptoms. The symptoms reported as most severe were tiredness, well-being, appetite, and pain. The overall symptom distress score was strongly correlated with the KDQOL-SF subscales symptom/problem list (r=-0.69, P<0.01), effects of kidney disease (r=-0.52, P<0.01), and burden of kidney disease (r=-0.50, P<0.01), as well as lower RAND-12 physical health composite (PHC) (r=-0.54, P<0.01) and lower RAND-12 mental health composite (MHC) (r=-0.62, P<0.001). In the multivariate regression analysis, after controlling for potential confounding variables including comorbidity using the modified Charlson Comorbidity Index, the ESAS symptom distress score remained strongly associated with the MHC (slope=-0.82+/-0.07, P<0.01) and PHC (slope=-0.48+/-0.07, P<0.01). The ESAS symptom distress score accounted for 29% of the impairment in PHC and 39% of the impairment in MHC. The intraclass correlation coefficient for the total symptom distress score in a 1-week test-retest was 0.70, P<0.01. Symptom burden is high and adversely affects HRQL in dialysis patients. The modified ESAS is a reliable, valid, simple, and useful method for regular symptom assessment in this patient population.

Aged↗
PubMed2006

Characterization of surface soils at a former uranium mill.

Dawn Mining Company operated a uranium mill in Stevens County, Washington, from 1957 to 1982, to process ore from the Midnite Mine, and from 1992 through 2000, to extract uranium from mine water treatment sludge. The mill was permanently shut down in 2001 when the Dawn Mining Company radioactive materials license was amended to allow direct disposal of water treatment sludge to a tailings disposal area at the mill. The mill building was demolished in 2003. Site soil characterization took place in 2004. Soil cleanup is ongoing. Contaminated soils on the site were characterized using a GPS-based gamma scanning system. A correlation between shielded gamma exposure rate and concentration of Ra in surface soils was developed. Subsurface soils were sampled using backhoe trenches. This system proved efficient and accurate in guiding development of the remedial action planning for the site and subsequent soil cleanup.

Gamma Rays↗
PubMed2006

Self-monitoring in Type 2 diabetes: a randomized trial of reimbursement policy.

AIM: Self-monitoring of blood glucose is often considered a cornerstone of self-care for patients with diabetes. We assessed whether provision of free testing strips would improve glycaemic control in non-insulin-treated Type 2 diabetic patients. METHODS: Adults with Type 2 diabetes, excluding those with private insurance or using insulin, were recruited through community pharmacies and randomized to receive free testing strips for 6 months or not; all patients received similar baseline education and a glucose meter. Primary outcome was change in HbA(1c) over 6 months. RESULTS: We randomized 262 patients (131 intervention and 131 control subjects). Mean age was 68.4 years (sd 10.9), 48% were male, mean duration of diabetes was 8.2 years (sd 7.2), 97% used oral glucose-lowering agents and mean baseline HbA(1c) was 7.4% (sd 1.2). After 6 months, we observed no difference in HbA(1c) between intervention and control patients, after adjusting for baseline HbA(1c)[adjusted difference 0.03, 95% confidence interval (CI) -0.16, 0.22; P = 0.78]. A per protocol analysis of study completers (152/262; 60%) yielded similar results. Intervention patients reported testing 0.64 days per week more often than control subjects (95% CI 0.18, 1.10; P = 0.007), although testing was not associated with better glycaemic control (Pearson r = -0.10, P = 0.12). CONCLUSIONS: Reducing financial barriers by providing free testing strips did not improve glycaemic control in patients with Type 2 diabetes not using insulin. Our results question the value of policies that reduce financial barriers to testing supplies in this population.

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PubMed2005

Characterization of a highly purified, fully active, crystallizable RC-LH1-PufX core complex from Rhodobacter sphaeroides.

Photosynthetic complexes in bacteria absorb light and undergo photochemistry with high quantum efficiency. We describe the isolation of a highly purified, active, reaction center-light-harvesting 1-PufX complex (RC-LH1-PufX core complex) from a strain of the photosynthetic bacterium, Rhodobacter sphaeroides, which lacks the light-harvesting 2 (LH2) and contains a 6 histidine tag on the H subunit of the RC. The complex was solubilized with diheptanoyl-sn-glycero-3-phosphocholine (DHPC), and purified by Ni-affinity, size-exclusion and ion-exchange chromatography in dodecyl maltoside. SDS-PAGE analysis shows the complex to be highly purified. The quantum efficiency was determined by measuring the charge separation (DQA --> D+QA -) in the RC as a function of light intensity. The RC-LH1-PufX complex had a quantum efficiency of 0.95 +/- 0.05, indicating full activity. The stoichiometry of LH1 subunits per RC was determined by two independent methods: (i) solvent extraction and absorbance spectroscopy of bacteriochlorophyll, and (ii) density scanning of the SDS-PAGE bands. The average stoichiometry from the two measurements was 13.3 +/- 0.9 LH1/RC. The presence of PufX was observed in SDS-PAGE gels at a stoichiometry of 1.1 +/- 0.1/RC. Crystals of the core complex have been obtained which diffract X-rays to 12 A. A preliminary analysis of the space group and unit cell analysis indicated a P1 space group with unit cell dimensions of a = 76.3 A, b = 137.2 A, c = 137.5 A; alpha = 60.0 degrees , beta = 89.95 degrees , gamma =90.02 degrees .

Bacterial Proteins↗
PubMed2005

Epidemiology of capsular and surface polysaccharide in Staphylococcus aureus infections complicated by bacteraemia.

Staphylococcus aureus is a leading cause of serious hospital- and community-acquired infections. The discovery of serologically distinct capsular polysaccharides on the surface of clinical isolates has allowed the development of vaccines and passive protective immunity. We have studied patient characteristics, infection characteristics and the surface and capsular polysaccharide serotype distribution in patients with S. aureus infections complicated by bacteraemia admitted to VA hospitals in Maryland between 1995 and 2000. Nine hundred and ninety-three blood cultures from 331 patients were positive for S. aureus. Thirty-eight percent of patients had diabetes, 11% had end-stage renal failure, and 23% were injection drug users. Forty-two percent of infections were caused by methicillin-resistant strains (MRSA), and 60% were acquired during hospitalization. Serotyping of the first available isolate per patient (N=234 isolates) using polyclonal antibodies showed three major phenotypes--42%, type 8 (T8) capsule; 50%, type 5 (T5) capsule; and 8%, 336 polysaccharide. MRSA isolates were significantly more likely to be T5 than methicillin-susceptible isolates (66% vs. 39%, P<0.001). The proportion of T5 MRSA increased significantly (years 1-2: 41%; years 3-4: 65%; years 5-6: 90%, P<0.001). This large sample of patients with serious S. aureus infection confirms that capsular polysaccharides T5 and T8 cause most human infections, and together with serotype 336, account for nearly all those with bacteraemia.

Bacteremia↗
PubMed2005

Association between beta-adrenergic receptor polymorphisms and their G-protein-coupled receptors with body mass index and obesity in women: a report from the NHLBI-sponsored WISE study.

OBJECTIVES: The beta-adrenergic receptor (betaAR) genes are candidate genes for obesity because of their roles in energy homeostasis and promotion of lipolysis in human adipose tissue. Objective is to determine the association between obesity and polymorphisms in genes of the beta(1)AR (ADRB1), beta(2)AR (ADRB2), beta(3)AR (ADRB3), Gs protein alpha (GNAS1), to which all three beta-receptors couple and the G protein beta3 subunit (GNB3), to which beta(3)ARs couple. DESIGN: A case-control genetic association study. SUBJECTS: A total of 643 black or white women enrolled in Women's Ischemia Syndrome Evaluation (WISE) study. MEASUREMENTS: Genotypes were determined by PCR with single primer extension. Associations between genotype and body mass index (BMI), waist-to-hip ratio (WHR), waist circumference, and obesity were made. RESULTS: Polymorphisms in the three betaAR genes, GNAS1, and GNB3 were not associated with BMI, WHR, waist circumference, or obesity. Linear and logistic regression analyses found no contribution of either genotype or haplotype with anthropometric measurements or obesity. CONCLUSIONS: Our study suggests that among American women with suspected coronary heart disease, polymorphisms in the betaARs and their G-protein-coupled receptors do not contribute to increased BMI, WHR, waist circumference, or obesity. Given that 50% of all women die from coronary heart disease, and a higher percentage have heart disease during their lifetime, our results are likely generalizable to many American women.

Adipose Tissue↗
PubMed2005

Sequencing drug response with HapMap.

The information about how DNA sequence varies across the human genome is crucial for unravelling the genetic basis of drug response. A haplotype map, or HapMap, intended to reveal such a variation pattern, has been recently developed by the International HapMap Consortium. Here, we present a conceptual model for directly characterizing specific DNA sequence variants that are responsible for drug response based on the haplotype structure provided by HapMap. Our model is developed in the maximum likelihood context, incorporated by clinically meaningful mathematical functions that model drug response and implemented with the EM algorithm. Our model is employed to a pharmacogenetic study of cardiovascular disease with 107 patients. We found that the haplotype constituted by allele Gly16 (G) at codon 16 and allele Glu27 (G) at codon 27 genotyped within the beta2AR candidate gene exhibits a different effect on heart rate curve from the rest haplotypes. Parents with the diplotype consisting of two copies of haplotype GG are more sensitive in heart rate to increasing dosages of dobutamine than those with other haplotypes. This model provides a powerful tool for elucidating the genetic variants of drug response and ultimately designing personalized medications based on each patient's genetic constitution.

Algorithms↗
PubMed2005

Reduced cardiovascular morbidity and mortality associated with metformin use in subjects with Type 2 diabetes.

AIM: Metformin therapy reduces microvascular complications in Type 2 diabetes; questions remain, however, regarding its impact on macrovascular events. This study examined metformin use in relation to risk of cardiovascular-related hospitalization and mortality. METHODS: We conducted a retrospective cohort analysis, using Saskatchewan Health administrative databases to identify new users of oral antidiabetic drugs. Subject groups were defined by medication use during 1991-1999: sulphonylurea monotherapy, metformin monotherapy, or combination therapy. Deaths and non-fatal hospitalizations recorded during the study period were identified as cardiovascular-related from ICD-9 codes. The main outcome was a composite of first non-fatal hospitalization or death. Standard multivariate techniques, including propensity scores, were used to adjust for potential confounding. Multivariate Cox proportional hazard models were used to examine the relationship between metformin use and the composite endpoint. RESULTS: Metformin monotherapy was associated with a lower risk of the composite endpoint (adjusted hazard ratio 0.81; 95% confidence interval 0.68, 0.97) compared with sulphonylurea monotherapy. Combination therapy with meformin and a sulphonylurea was associated with lower mortality, but had similar hospitalization rates, to sulphonylurea monotherapy. CONCLUSIONS: Metformin monotherapy was associated with a lower risk of cardiovascular-related morbidity and mortality, and combination metformin and sulphonylurea therapy was associated with a reduced risk of fatal cardiovascular events, when compared with sulphonylurea monotherapy.

Aged↗
PubMed2005

A pharmacodynamic model of the effects of controlled-onset extended-release verapamil on 24-hour ambulatory blood pressure.

OBJECTIVE: To formulate and evaluate a pharmacodynamic model that characterizes the effects of S-verapamil on the circadian 24-hour ambulatory blood pressure (ABP). METHODS: ABP was recorded in 19 hypertensive patients off drug, and following administration of the targeted dose of COER-V given once daily for at least 30 days. Blood samples were collected after the last dose for determination of the pharmacokinetic of S-verapamil. ABP vs. time was analyzed using a cosinor function, and the effects of S-verapamil on ABP were fitted using the pharmacodynamic model. RESULTS: COER-V decreased average systolic and diastolic blood pressures (mesors): baseline, 142 +/- 10 and 90 +/- 7; treated, 132 +/- 8.8 and 83 +/- 6.6 mmHg, respectively (p < 0.001). COER-V had no effect on the amplitude, cycle or the time shift (acrophase). The mean +/- SD time to peak and maximal S-verapamil concentrations were 9.5 +/- 1.2 hours and 46.4 +/- 35.8 ng/ml, respectively. Model estimates of the maximal inhibited systolic (Emax S), diastolic. (Emax D) pressures and C50 were 101 +/- 14 mmHg, 61 +/- 9.9 mmHg and 32.9 +/- 22.8 ng/ml, respectively. The model fit of the data was satisfactory and parameter estimates were precise. CONCLUSIONS: The model may be useful to characterize the relationship between plasma concentrations of verapamil and the antihypertensive effects of the drug and may be suitable for characterizing the effect of drugs on biological functions displaying oscillatory behavior.

Antihypertensive Agents↗
PubMed2004

Protein kinase C modulation of cyclic GMP in rat neonatal pulmonary vascular smooth muscle.

Protein kinase C (PKC) has been implicated in the control of vascular tone and mitogenesis in the adult pulmonary vasculature, but little is known about the role of PKC in the neonatal pulmonary vasculature. In addition, the vasodilator nitric oxide (NO) is important in the transition of the pulmonary circulation from fetal to postnatal life, and it is thought that attenuated production of NO and therefore, cGMP may contribute to the pathophysiology of a variety of forms of neonatal pulmonary vascular disease states. Although evidence exists for an interaction between PKC and NO in the adult pulmonary vasculature, the identification of specific roles for PKC in neonatal pulmonary vascular smooth muscle (NPVSM) has not been determined, and no studies have been done on the modulation of cGMP by PKC in NPVSM. Accordingly, immunoblot analysis revealed the expression of the alpha, delta, epsilon, and iota PKC isozymes in NPVSM. Treatment of NPVSM with 10 nM 4-beta phorbol myristate acetate (PMA), a PKC activator, induced translocation of PKCalpha, and PKCdelta from the soluble to the particulate fraction, while exposure to 10 nM endothelin-1 (ET-1), a potent vasoconstrictor and mitogenic substance, caused translocation of PKCdelta and PKCiota from the soluble to the particulate fraction. Sodium nitroprusside (SNP) significantly increased intracellular cGMP levels, an effect attenuated by PMA but not by ET-1. In addition, pretreatment with the specific PKC isozyme antagonist Go 6983 blocked the effect of PMA on cGMP levels. Collectively, these data demonstrate the expression and activation of multiple PKC isozymes in NPVSM, and indicate that PKC inhibits SNP-stimulated cGMP production in NPVSM. These data also suggest that complex intracellular signaling pathways by specific PKC isozymes may be important in the development of neonatal pulmonary vascular function.

Animals↗
PubMed2004

Animal growth promoters: to ban or not to ban? A risk assessment approach.

The use of antibiotics for animal growth promotion has been controversial because of the potential transfer of antibiotic resistance from animals to humans. Such transfer could have severe public health implications in that treatment failures could result. We have followed a risk assessment approach to evaluate policy options for the streptogramin-class of antibiotics: virginiamycin, an animal growth promoter, and quinupristin/dalfopristin, a antibiotic used in humans. Under the assumption that resistance transfer is possible, models project a wide range of outcomes depending mainly on the basic reproductive number (R(0)) that determines the potential for person-to-person transmission. Counter-intuitively, the benefits of a ban on virginiamycin were highest for intermediate values of R(0), and lower for extremely high or low values of R(0).

Animal Husbandry↗
PubMed2004

A statistical model for functional mapping of quantitative trait loci regulating drug response.

Differential drug response, that is, pharmacodynamics, is most often likely to be a complex trait, controlled by the combined influences of multiple genes and environmental influences. Genetic mapping has proven to be a powerful tool for detecting and identifying specific genes affecting complex traits, that is, quantitative trait loci (QTL), based on polymorphic markers. In this article, we present a novel statistical model for genetic mapping of QTL governing pharmacodynamic processes. In principle, this model is a combination of functional mapping proposed to map function-valued traits and linkage disequilibrium mapping designed to provide high-resolution mapping of QTL by making use of recombination events created at a historic time. We implement a closed-form solution for the Expectation-Maximization algorithm to estimate the population genetic parameters of QTL and the simplex algorithm to estimate the curve parameters describing the pharmacodynamic changes of different QTL genotypes in response to drug dose or concentrations. Extensive simulations are performed to investigate the statistical properties of our model. The implications of our model in pharmacogenetic and pharmacogenomic research are discussed.

Algorithms↗
PubMed2004

Resistance to disruption and gapping of peripheral nerve repairs: an in vitro biomechanical assessment of techniques.

One potential cause of suboptimal results after nerve repair is disruption or gapping of the neurorrhaphy in the postoperative period. This study assesses the biomechanical strength of five nerve repair techniques: fibrin glue, simple epineurial sutures, and three other novel neurorrhaphy methods. Fifty rabbit sciatic nerve segments were divided and repaired utilizing one of five different methods, producing five groups of ten specimens. Fibrin glue and four epineurial suture techniques (simple, horizontal mattress, "Tajima," "Bunnell") were employed. Repaired nerve segments were ramp-loaded to failure on an Instron 8300 materials-testing machine at a displacement rate of 5 mm/min. Gapping at the repair site was captured using high-resolution video. Differences among the five groups were assessed for significance using ANOVA and Fisher's protected least squares differences post-hoc testing. The mean force to produce disruption was higher for mattress suture repairs relative to simple repairs, but not significantly so (p = 0.31). Both were significantly stronger than fibrin glue repairs (p < 0.0001). "Tajima" and "Bunnell" repairs were both statistically stronger than glue (p < 0.0001), simple (p < 0.0001), or mattress (p = 0.0004) repairs, but not significantly different from one another (p = 0.48). Data for gapping at the repair site were similar with all suture techniques outperforming fibrin glue (p = 0.003). "Bunnell" repairs demonstrated the most resistance to gapping, compared to glue (p < 0.0001), simple (p = 0.0001), mattress (p = 0.007) and "Tajima" repairs (p = 0.01). These data demonstrate that repairs done utilizing fibrin glue are significantly weaker than all types of suture repairs. Two novel techniques for nerve repair (epineurial "Tajima" and "Bunnell") are significantly more resistant to disruption and gapping. Further evaluation to assess the effect of these repair techniques on function is required.

Animals↗
PubMed2004

Statin use in Type 2 diabetes mellitus is associated with a delay in starting insulin.

AIMS: It has been suggested that HMG Co-A reductase inhibitors ('statins') may reduce the risk of developing Type 2 diabetes mellitus. This study was designed to evaluate whether use of statins would also delay progression to insulin therapy. METHODS: This was a retrospective cohort study using Saskatchewan Health databases to identify subjects newly started on oral antidiabetic agents from 1991 to 1996. SUBJECTS: < 30 years of age or with previous lipid-lowering drug use were excluded. Medications known to influence glycaemic control, co-morbidity, and demographic data were collected. Statin exposure was defined as at least 1 year of use. Primary outcome was starting insulin treatment. Multivariate Cox proportional hazards models were used to examine the association between statin use and starting insulin. RESULTS: The final cohort included 10,996 new users of oral antidiabetic agents, of which 484 (4.4%) used statins. Mean age was 64 years and 55% were male. Mean duration of follow-up was 5.1 years; 11.1% (n = 1221) eventually started insulin treatment. Statin users were no less likely than non-users to start insulin treatment eventually (11.6% vs. 11.1%, P = 0.74). After multivariate adjustment, however, statin use was associated with a 10-month delay before newly treated diabetic subjects needed to start insulin treatment (adjusted hazard ratio 0.74; 95% confidence interval 0.56, 0.97, P = 0.028). CONCLUSION: The use of statins is associated with a delay in starting insulin treatment in patients with Type 2 diabetes initially treated with oral antidiabetic agents. Whether this relationship exists for patients at high risk of developing diabetes should be examined in a randomized trial.

Administration, Oral↗
PubMed2004

Thermal death kinetics of red flour beetle (Coleoptera: Tenebrionidae).

While developing radio frequency heat treatments for dried fruits and nuts, we used a heating block system developed by Washington State University to identify the most heat-tolerant life stage of red flour beetle, Tribolium castaneum (Herbst), and to determine its thermal death kinetics. Using a heating rate of 15 degrees C/min to approximate the rapid heating of radio frequency treatments, the relative heat tolerance of red flour beetle stages was found to be older larvae > pupae and adults > eggs and younger larvae. Lethal exposure times for temperatures of 48, 50, and 52 degrees C for the most heat-tolerant larval stage were estimated using a 0.5th order kinetic model. Exposures needed for 95% mortality at 48 degrees C were too long to be practical (67 min), but increasing treatment temperatures to 50 and 52 degrees C resulted in more useful exposure times of 8 and 1.3 min, respectively. Red flour beetle was more sensitive to changes in treatment temperature than previously studied moth species, resulting in red flour beetle being the most heat-tolerant species at 48 degrees C, but navel orangeworm, Amyelois transitella (Walker), being most heat tolerant at 50 and 52 degrees C. Consequently, efficacious treatments for navel orangeworm at 50-52 degrees C also would control red flour beetle.

Animals↗