Biomedical subjects

M Seaton

Publications and source records attributed to M Seaton.

7 recordsLinked to original sources

PubMed2001

Factors contributing to the development of medial tibial stress syndrome in high school runners.

STUDY DESIGN: Predictive correlational study. OBJECTIVES: To identify the incidence of medial tibial stress syndrome (MTSS) in a group of high school cross-country runners and to determine if a relationship exists between lower extremity structural measures and the incidence of MTSS. BACKGROUND: Medial tibial stress syndrome is an overuse injury that occurs in long-distance runners. Literature exists that implicates structural deformity as a contributor to MTSS, but no studies have developed a predictive model. METHODS AND MEASURES: We measured 125 high school cross-country runners for tibiofibular varum, resting calcaneal position during stance, and gastrocnemius length. Runners developing MTSS over an 8-week period were placed in the injured group (2 men, 13 women; age 15.3 years 1.0), and 21 randomly selected uninjured runners were placed in the uninjured group (13 men, 8 women; age 15.7 years +/-1.5). Navicular drop was measured for runners in both groups. Reliability of measures was determined using an intraclass correlation coefficient (ICC 3,1). Paired t tests were used to compare the injury and noninjury groups. A logistic regression analysis was used to establish if the descriptive data could accurately predict the development of MTSS. RESULTS: Paired t tests showed a significant difference in navicular drop test measures between the injured (6.8 mm 3.7) and noninjured (3.6 mm 3.3) groups. Logistic regression analysis revealed navicular drop test measurements and sex correctly identified athletes who developed MTSS with 76% accuracy. CONCLUSION: Our study supported the hypothesis that a pronatory foot type is related to MTSS. The combination of sex and navicular drop test measures provides an accurate prediction for the development of MTSS. Clinical measures that identify biomechanical risk factors for MTSS may allow prevention or early intervention.

Adolescent↗

PubMed1996

Metabolism of butadiene by mice, rats, and humans: a comparison of physiologically based toxicokinetic model predictions and experimental data.

1,3-Butadiene is a carcinogen in rats and mice, with mice being substantially more sensitive than rats. Our recent research is directed toward obtaining a better understanding of the cancer risk of butadiene in humans by evaluating species-dependent differences in the formation of the toxic metabolites epoxybutene and diepoxybutane. The recent data include in vitro studies on butadiene metabolism using tissues from humans, rats, and mice as well as experimental data and physiological model predictions for butadiene in blood and butadiene epoxides in blood, lung, and liver after exposure of rats and mice to inhaled butadiene. The findings suggest that humans would be more like rats and less like mice regarding the formation of butadiene epoxides. These research findings permit a reassessment of some default options that are used in carcinogen risk assessments. The research approach employed can be a useful strategy for developing mechanistic and toxicokinetic data to supplant default assumptions used in carcinogen risk assessments.

Animals↗

PubMed1992

Upper extremity impairment in workers performing repetitive tasks.

A series of subjective and objective measures were chosen to determine impairment of upper extremity function in 157 workers performing repetitive tasks. Workers were asked to respond to questions regarding their perception of the presence or absence of numbness, pain, weakness, or swelling in their upper extremities. Objective tests consisted of the measurement of grip strength, pinch strength, Semmes-Weinstein monofilament sensory responses, vibrometer responses, neurometer measurement, and the presence or absence of Tinel's or Phalen's signs. These measures were considered collectively to estimate the overall levels of impairment of each individual. Overall findings show that 55 percent of workers examined had impairment scores of 2 or more and 75 percent had scores of 1 or more. Significant differences were found in impairment ratings between job types. Those jobs requiring the highest repetition with the least rest per cycle had the highest impairment ratings. Workers that rotated jobs had impairment scores significantly less (p less than 0.005) than the average of workers performing single-task jobs. We conclude that cumulative trauma disorders are more prevalent than originally believed and that the disorder is best examined from an overall functional impairment perspective.

Adult↗

PubMed1992

Grip strength before and after carpal tunnel decompression.

We prospectively studied preoperative and postoperative grip and pinch strength in 21 patients having 30 consecutive median nerve decompressions for carpal tunnel syndrome. All procedures were done by one surgeon. Each hand operated on served as its own control and was studied by the same therapist preoperatively and at monthly intervals for 6 months after the procedure. An initial decline in both grip and pinch strength was noted in most hands during the first postoperative month. Eighty percent or more grip strength was regained in 65% of the hands at 2 months and in 81% at 3 or more months. In those hands (65%) that regained at least 100% of their preoperative grip strength at 3 or more months, there was an average increase in maximal grip of 56%, as compared with an average decrease of 20% in the remaining hands (35%).

Adult↗

PubMed1988

No evidence for vitamin K-dependent carboxylation of canine surfactant apoproteins, 28-36 kDa.

Recent research has shown that rat surfactant apoproteins (26-38 kDa) are vitamin K-dependent [Rannels, Gallaher, Wallin & Rannels (1987) Proc. Natl. Acad. Sci. U.S.A. 84, 5952-5956]. We have investigated the effect of the vitamin K antagonist warfarin on this family of apoproteins in surfactant from dog lung. Our data suggest that warfarin does not interfere with synthesis and secretion of these proteins into dog lung surfactant. Abnormal surfactant apoproteins, produced in response to warfarin treatment of the dog, were also not found in lung surfactant. 4-Carboxyglutamic acid analysis of purified dog apoproteins also failed to detect the vitamin K-modification. When vitamin K-dependent 14C labelling of precursors of vitamin K-dependent proteins was carried out, fluorography of these precursors, when electrophoresed into SDS/polyacrylamide gels, revealed 14C-labelled proteins of apparent molecular mass 74, 46, 42, 34, 31 and 23 kDa. Antibodies produced against purified dog surfactant apoproteins recognized precursors of the surfactant apoproteins in lung microsomes but did not recognize any 14C-labelled carboxylase substrates. These precursors appeared on immunoblots with apparent molecular mass 29, 32, 33 and 50 kDa. Our data suggest that there are significant differences between this class of surfactant apoproteins in the rat and the dog.

Animals↗

PubMedDate not supplied

The National Model Fire Prevention Code: who's going to write it?

The user-friendly and vastly improved NFPA 1, Fire Prevention Code, is the best fire prevention code out there. Here's how NFPA worked toward consensus on the document, and why it's getting rave reviews from fire marshals and inspectors nationwide.

Building Codes↗

PubMedDate not supplied

Nicotine metabolism in stumptailed macaques, Macaca arctoides.

Stumptailed macaques received a single i.v. dose of 14C-nicotine (5 microCi and 300 micrograms/kg) on several separate occasions to establish baselines. Then they were pretreated with phenobarbital (2.0 mg/kg/day im for 7 days) and 8 weeks later pretreated with cimetidine (8.5 mg/kg/day im for 4 days). Nicotine in the same dose as before was readministered after each pretreatment. The baseline pattern of nicotine metabolism observed in plasma and urine, highly reproducible within and between macaques, closely resembled that previously reported in humans using GC and HPLC analysis. In urine, nicotine and eight metabolites were identified, including high concentrations of metabolites A and G. Recently discovered in humans, metabolites A and G are of special interest for their long duration in the body. Phenobarbital pretreatment accelerated rates of production of all nicotine metabolites except nornicotine and nicotine-1'-N-oxide, whereas cimetidine retarded rates of production of five metabolites. Sex differences in nicotine metabolism resembled those reported in humans. Collectively, these results suggest that the stumptailed macaque may be a useful model for certain aspects of nicotine metabolism in humans.

Animals↗