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Biomedical subjects

M L Myers

Publications and source records attributed to M L Myers.

At least 19 recordsLinked to original sources
PubMed2006

Seatbelt use during tractor overturns.

In 2002, the Kentucky Farm Tractor Overturn Survey was administered, in which 6,063 randomly selected farm operators responded to questions that addressed the presence and use of seatbelts in the event of a tractor overturn. Data were analyzed to determine the proportion of seatbelt presence and use on tractors that overturned differentiated by whether they were equipped or not equipped with a rollover protective structure (ROPS). In 537 overturns reported for which the ROPS status was known, 92 involved ROPS-equipped tractors, of which 60 had a functioning seatbelt, and 19 operators of these tractors used the seatbelt that was present during the overturn. However, of the 445 overturns of non-ROPS tractors, eight had a functioning seatbelt, and three of these operators wore the seatbelt. Two of the three operators that wore seatbelts on non-ROPS tractors suffered a permanent disability. In contrast, of the 19 operators who wore a seatbelt on ROPS-equipped tractors, 18 experienced no or minor injuries, and one required outpatient care. Seatbelts are known to save lives but are a secondary safety device to ROPS, for ROPS alone saves lives and is a necessary pre-condition for seatbelt presence and use.

Accidents, Occupational↗
PubMed2006

Frequency and severity of injuries to operators during overturns of farm tractors.

Previous estimates of operator death from farm tractor overturn events range from 0.03 to 0.68. This study provided population-based estimates of the denominator of total farm tractor overturns and the frequency of six classes of overturn injury outcomes for tractors with and without rollover protective structures (ROPS). A 40-item telephone survey collected information from a random sample of 6,063 (8.0%) Kentucky farms about each farm's most recent overturn. A total of 551 (9.1%) farms reported overturns, and 5,512 (90.1%) reported no overturns. Injury outcomes for 443 overturns of non-ROPS tractors and 89 ROPS tractors were distributed as follows: no or minor injury (non-ROPS: 70.43%; ROPS: 82.02%), outpatient treatment (non-ROPS: 21.90%; ROPS: 9.00%), hospital admission (non-ROPS: 15.35%; ROPS: 3.37%), temporary disability (non-ROPS: 13.54%; ROPS: 14.61%), permanent disability (non-ROPS: 3.16%; ROPS: 0.00%), and death (non-ROPS: 5.42%; ROPS: 1.12%). (Percents total to more than 100 because some operators treated as outpatients were subsequently hospitalized, disabled, or died.) The observed 0.054 probability of death from overturn of non-ROPS tractors in this sample was corrected for the proportion of farms that went out of business prior to the survey and thus were excluded from the sampling frame. The adjusted 0.08 probability of death from overturn of a non-ROPS tractor is five times smaller than the NIOSH estimate of 0.40. The discrepancy lies in the much larger denominator of all non-fatal and fatal overturns than assumed previously.

Accidents, Occupational↗
PubMed2005

Cost effectiveness of a dealer's intervention in retrofitting rollover protective structures.

OBJECTIVE: To evaluate the cost effectiveness of a 4.5 year education campaign that promoted farmers' adoption of rollover protective structures (ROPS) to prevent tractor overturn injuries. DESIGN: Randomized controlled trial, decision analysis, and cost effectiveness analysis. SETTING: One treatment county and one control county in the State of Kentucky. INTERVENTION: A campaign by a local tractor and equipment dealership to encourage farmers to purchase and install ROPS and seatbelt retrofit kits for older tractors. MAIN OUTCOME MEASURES: Number of injuries averted and cost per injury averted. RESULTS: The dealership's 4.5 year intervention was shown to potentially reduce both fatal (0.26) and non-fatal (1.50) injuries by 2.6% in its county over the intervention period using a 20 year analytic horizon. When extrapolated statewide, 6.7 lives would be saved and 39 non-fatal injuries would be averted over the combined 24.5 year combined intervention period and analytic horizon. The intervention for this period was cost effective with a "savings" of 35,713 dollars per injury (fatal plus non-fatal) averted at a 4% discount rate. CONCLUSIONS: Tractor manufacturer promotions can influence their dealerships to promote ROPS retrofits by their customers. A manufacturer backed dealer ROPS retrofit campaign was cost effective in reducing overturn related injuries.

Accident Prevention↗
PubMed2004

Cost-effectiveness of a ROPS retrofit education campaign.

A community educational campaign implemented in two Kentucky counties was effective in influencing farmers to retrofit their tractors with rollover protective structures (ROPS) to protect tractor operators from injury in the event of an overturn. This article reports on the cost-effectiveness of this program in the two counties when compared to no program in a control county. A decision analysis indicated that it would be effective at averting 0.27 fatal and 1.53 nonfatal injuries over a 20-year period, and when this analysis was extended statewide, 7.0 fatal and 40 nonfatal injuries would be averted in Kentucky. Over the 20-year period, the cost-per-injury averted was calculated to be $172,657 at a 4% annual discount rate. This cost compared favorably with a national cost of $489,373 per injury averted despite the additional program cost in Kentucky. The principle reason for the increased cost-effectiveness of the Kentucky program was the three-fold higher propensity for tractors to overturn in Kentucky. The cost-per-injury averted in one of the two counties was $112,535. This lower cost was attributed principally to incentive awards financed locally for farmers to retrofit their tractors with ROPS.

Accident Prevention↗
PubMed2002

Molecular analysis of Vibrio parahaemolyticus isolated from human patients and shellfish during US Pacific north-west outbreaks.

AIMS: The objective of this study was to investigate the occurrence and distribution of haemolysin genes, plasmid profile, serogroup analysis and cellular urease activity for Vibrio parahaemolyticus isolates from infected human patients and oysters from the Pacific north-western United States between 1988 and 1997. METHODS AND RESULTS: All of the clinical and environmental isolates tested in this study exhibited the presence of the thermolabile haemolysin gene, tl, confirming that all of the isolates were V. parahaemolyticus. Furthermore, the V. parahaemolyticus isolates that contained either the thermostable direct haemolysin gene, tdh, or the thermostable direct haemolysin-related gene, trh, or both, were also positive for urease. Isolates from infected human patients belong to serogroups O1 and O4, whereas, the isolates from oysters belong to serogroups O1, O4 and O5. These results suggest that the presence of a V. parahaemolyticus serogroup O1 and O4 could indicate the presence of a virulent strain of this pathogen. In this study, the presence of the haemolysin genes, serogroup profiles and urease production in V. parahaemolyticus isolated from human patients correlated with the oysters collected during the outbreaks. However, no significant correlation of the plasmid profiles was detected, based on their distribution and molecular weights, between V. parahaemolyticus isolated from infected human patients and from oysters collected during this outbreak. CONCLUSIONS, SIGNIFICANCE AND IMPACT OF STUDY: It is apparent from this study that the identification of the haemolysin genes by multiplex PCR amplification, in conjunction with serogroup analysis and urease production, can be used to monitor shellfish for the presence of potentially pathogenic strains of V. parahaemolyticus.

Animals↗
PubMed2002

Tractor risk abatement and control as a coherent strategy.

The agricultural tractor was the principal source of fatal injury on American farms for the latter part of the 20th century, and they maintain that distinction today. Much has been learned about the toll of these fatalities and how to prevent them over the last ten years, yet public policy has generally been unsuccessful in reducing this toll. A policy conference entitled Tractor Risk Abatement and Control convened in 1997 to develop recommendations to reduce this death toll. Several stakeholders at the conference agreed on 25 action items, which if implemented would reduce the number of tractor-related deaths by more than 2,000 by the year 2015. These recommendations relate to tractor overturns, runovers, and traffic collisions as well as youth operators. This article addresses the completeness of a strategy for preventing tractor-related injuries for each of these four areas based upon an evaluation model derived from the Theory of Planned Behavior and an antecedent model. The ultimate result of this model is to influence an individual's intention to act to prevent injury. The set of recommendations was found to provide a coherent strategy. In addition, implementing the strategy at an organizational level is discussed.

Accidents, Occupational↗
PubMed2001

Incidental malignancy in internal thoracic artery lymph nodes.

The incidental finding of malignant internal thoracic lymph nodes while mobilizing the internal thoracic artery (ITA) for coronary bypass grafting has not to our knowledge been previously reported. The cases of 3 male patients who underwent surgery between January 1990 and January 1993 and in whom malignant lymph nodes were found in the ITA pedicle are reviewed. One individual was found to have metastatic carcinoma of the breast, whereas the other 2 were discovered to have previously undiagnosed lymphomas. After undergoing further relevant investigation and treatment, all 3 patients remain free of recurrent disease 6.8 to 9.8 years after their original cardiac surgery. Primary or metastatic malignancy may be encountered in the course of ITA mobilization for grafting. Abnormally enlarged internal thoracic lymph nodes should be sent for pathologic examination.

Aged↗
PubMed2001

Constancy of bond strength in 5 single-bottle dentin bonding systems.

OBJECTIVE: Historically, wide variations in the shear bond strength of resin composite bonded to dentin have been reported. The purpose of this study was to compare 5 commercially available single-bottle dentin bonding systems while controlling several sources of variation in shear bond strengths. METHOD AND MATERIALS: Extracted molars were stored for 2 weeks in 0.5% Chloramine T. The teeth were mounted, the occlusal enamel was removed to expose middle dentin, and the exposed dentin was etched and treated according to 1 of 6 protocols. Finally, a cylinder of resin-based composite was bonded to the dentin. After 24 hours, specimens were fractured under shear force, and the results were recorded in megapascals. RESULTS: The type of product used was significantly associated with the mean shear bond strength observed. All products exhibited some degree of variation from specimen to specimen. One product, PQ1, exhibited less variation than the other 4 products. CONCLUSION: PQ1 was found to have a significantly higher mean shear bond strength than the other 4 products tested. There was no significant difference between specimens bonded to dry dentin and specimens bonded to wet dentin when using PQ1.

Acetone↗
PubMed2001

Tray delivery of potassium nitrate-fluoride to reduce bleaching sensitivity.

OBJECTIVE: Tooth sensitivity is a common side effect associated with tooth whitening. The purpose of this study was to determine if bleaching tray delivery of potassium nitrate-fluoride reduces bleaching sensitivity enough to allow continuation of whitening treatment. METHOD AND MATERIALS: Thirty patients were enrolled in a university-approved clinical study and had their teeth bleached at night with 10% carbamide peroxide in a custom-fitted tray. The bleaching tray was a rigid experimental design for which sensitivity was expected. If tooth sensitivity was experienced, the patient applied a gel containing 5% potassium nitrate and 1,000 ppm sodium fluoride in the bleaching tray for various time periods. Log forms were collected upon completion of bleaching, and patient interviews were used to compare effects of the gel before and after sensitivity treatment. RESULTS: Sixteen out of 30 patients experienced tooth sensitivity. Of those 16 patients, 12 used the gel, and 11 of the 12 reported a reduction in sensitivity. Treatment times ranged from 10 minutes before bleaching to 30 minutes before and after. The number of applications ranged from one to continuous use. Some patients were able to continue bleaching after one gel application with no subsequent sensitivity. Other patients were unable to continue bleaching unless they continued using the gel. The incidence of tooth sensitivity (53%) reported in this study is consistent with sensitivity reported in studies using semi-rigid custom-fitted trays made from stone casts with a nonscalloped, nonreservoir design. CONCLUSION: The use of a 5% potassium nitrate-fluoride gel applied in the tray as needed for tooth sensitivity associated with nightguard vital bleaching can reduce sensitivity in a majority of patients and allow most patients to continue bleaching to completion.

Carbamide Peroxide↗
PubMed2000

Endotoxin induces a dose-dependent myocardial cross-tolerance to ischemia-reperfusion injury.

OBJECTIVE: To test whether or not endotoxin induces a dose-dependent reduction of myocardial contractile dysfunction after a standardized period of myocardial ischemia and reperfusion and whether nitric oxide is involved in this form of myocardial protection. DESIGN: Prospective, randomized, controlled animal study. SETTING: University research laboratory. SUBJECTS: Twenty-five male Sprague-Dawley rats. INTERVENTIONS: After anesthesia, the left carotid artery was cannulated under sterile conditions and animals were allowed to recover from surgery for 12 hrs. Sterile saline or increasing doses (2.5, 5, or 10 mg/kg body weight) of endotoxin (Escherichia coli O26:B6; Sigma, Mississauga, Ontario, Canada) were given intravenously (1 mL over 5 mins). In some rats, diaspirin-crosslinked hemoglobin (200 mg/kg) was infused 6 hrs and 60 min before endotoxin infusion (10 mg/kg). Hearts were rapidly excised for retrograde perfusion through the ascending aorta (Langendorff apparatus) 6 hrs later. After baseline data collection, hearts were subjected to global ischemia (30 mins, 37 degrees C [98.6 degrees F]), followed by 30 mins of reperfusion. MEASUREMENTS AND MAIN RESULTS: Physiologic variables were recorded 6 hrs after saline and endotoxin infusion. Baseline myocardial systolic contractility and diastolic compliance were assessed, respectively, by left ventricular developed pressure (LVDP) and left ventricular (LV) volume-preload relationships. After 30 min of reperfusion, LVDP recovery and left ventricular end-diastolic pressure were measured. Endotoxin induced LV systolic contractile depression, irrespective of the dose of endotoxin administered. LV diastolic dysfunction varied between different doses of endotoxin administered. On reperfusion, endotoxin produced a dose-dependent improvement of postischemic LVDP recovery: 30+/-6% in sham, 78+/-9% in 2.5 mg/kg, 93+/-8% in 5 mg/kg, and 107+/-10% in 10 mg/kg endotoxin heart. In rats treated with 10 mg/kg endotoxin, diaspirin-crosslinked hemoglobin pretreatment abrogated endotoxin-induced postischemic LVDP recovery improvement (105+/-10% vs. 43+/-7%, p = .01). CONCLUSION: Sublethal doses of endotoxin induce in a dose-dependent manner a delayed form of myocardial protection against ischemia. Although free-cell hemoglobin solution abrogates this endotoxin-induced cross-tolerance, we propose that possible mechanisms involved in this form of myocardial protection include nitric oxide pathway activation.

Animals↗
PubMed2000

Prevention effectiveness of rollover protective structures--Part I: Strategy evolution.

This is the first of three articles that evaluate the health and economic consequences of the use of rollover protective structures (ROPS) on agricultural tractors. The effectiveness of ROPS delivered through alternative intervention strategies is the subject of the three-part study. This part of the study reviews and assesses the evolution of interventions that are known to prevent injuries incurred as a result of tractor overturns. The method used is historical analysis framed against a prevention effectiveness model used by the U.S. Centers for Disease Control and Prevention. Two intervention strategies were found to be potentially effective in preventing injuries from tractor overturns. These strategies are either to install a ROPS on tractors that lack a ROPS or to replace the tractor with one that has a ROPS already mounted. Other prevention factors include the effectiveness and use of seatbelts and the integrity of the ROPS system during an overturn.

Accident Prevention↗