Temporomandibular joint: morphology and signal intensity characteristics of the disk at MR imaging

Magnetic resonance (MR) imaging has been used in the temporomandibular joint (TMJ) primarily to define the disk position. This report examines altered morphology and signal intensity characteristics of the TMJ disk as they relate to the severity of internal derangement. Two hundred sixteen joints in 133 patients with a history of such derangement. were imaged with MR. Disk position, signal intensity, morphology, and the presence of osteoarthritis were determined for each joint. The normal disk was not anteriorly displaced and had a normal "bow-tie" shape. A grade 1 disk was anteriorly displaced and had a normal shape; a grade 2 disk was anteriorly displaced and had an abnormal shape. Forty (19%) joints were considered normal; none of these exhibited osteoarthritis. One hundred thirty-nine (64%) joints were grade 1; osteoarthritis was found in 17%. Thirty-seven (17%) were grade 2; osteoarthritis was found in 95%. All forty normal joints had high or intermediate signal intensity in the disk. Osteoarthritic joints had a higher percentage of disks with diminished intensity (P less than .0001). Severe or untreated osteoarthritis is known to be a complication of TMJ internal derangements; hence this grading system seems to correlate with the severity of internal derangement.     

Use of injury severity variables in determining disability and community integration after traumatic brain injury

BACKGROUND: Long-term outcome is important in managing traumatic brain injury (TBI), an epidemic in the United States. Many injury severity variables have been shown to predict major morbidity and mortality. Less is known about their relationship with specific long-term outcomes. METHODS: Glasgow Coma Scale, Revised Trauma Score, Injury Severity Score, and Trauma and Injury Severity Score, along with other demographic and premorbid values, were obtained for 378 consecutive patients hospitalized after TBI at a Level I trauma center between September 1997 and May 1998. Of this cohort, 120 patients were contacted for 1-year follow-up assessment with the Disability Rating Scale, Community Integration Questionnaire, and employment data. RESULTS: Univariate analyses showed these to be significant single predictors of 1-year outcome. Multivariate analyses revealed that the Revised Trauma Score and Glasgow Coma Scale had significant additive value in predicting injury variables Disability Rating Scale scores when combined with other demographic and premorbid variables studied. Predictive models of 1-year outcome were developed. CONCLUSION: Injury severity variables are significant single outcome predictors and, in combination with premorbid and demographic variables, help predict long-term disability and community integration for individuals hospitalized with TBI.     

Bystander Intervention Prior to The Arrival of Emergency Medical Services: Comparing Assistance across Types of Medical Emergencies

Objective: To determine the situational circumstances associated with bystander interventions to render aid during a medical emergency. Methods: This study examined 16.2 million Emergency Medical Service (EMS) events contained within the National Emergency Medical Services Information System. The records of patients following a 9-1-1 call for emergency medical assistance were analyzed using logistic regression to determine what factors influenced bystander interventions. The dependent variable of the model was whether or not a bystander intervened. Results: EMS providers recorded bystander assistance 11% of the time. The logistic regression model correctly predicted bystander intervention occurrence 71.4% of the time. Bystanders were more likely to intervene when the patient was male (aOR = 1.12, 95% CI = 1.12–1.3) and if the patient was older (progressive aOR = 1.10, 1.46 age group 20-29 through age group 60–99). Bystanders were less likely to intervene in rural areas compared to urban areas (aOR = 0.58, 95% CI = 0.58–0.59). The highest likelihood of bystander intervention occurred in a residential institution (aOR = 1.86, 95% CI = 1.85–1.86) and the lowest occurred on a street or a highway (aOR = 0.96, 95% CI = 0.95–0.96). Using death as a reference group, bystanders were most likely to intervene when the patient had cardiac distress/chest pain (aOR = 11.38, 95% CI = 10.93–11.86), followed by allergic reaction (aOR = 7.63, 95% CI = 7.30–7.99), smoke inhalation (aOR = 6.65, 95% CI = 5.98–7.39), and respiration arrest/distress (aOR = 6.43, 95% CI = 6.17–6.70). A traumatic injury was the most commonly recorded known event, and it was also associated with a relatively high level of bystander intervention (aOR = 5.81, 95% CI = 5.58–6.05). The type of injury/illness that prompted the lowest likelihood of bystander assistance was Sexual Assault/Rape (aOR = 1.57, 95% CI = 1.32–1.84) followed by behavioral/psychiatric disorder (aOR = 1.64, 95% CI = 1.57–1.71). Conclusion: Bystander intervention varies greatly on situational factors and the type of medical emergency. A higher risk of patient death is likely to prompt bystander action. These novel study results can lead to more effective first aid training programs.     

Cardiorespiratory fitness and body mass index values in 9-year-old rural Norwegian children

Aim: To describe cardiorespiratory fitness and body mass index (BMI) values in a representative population of 9-year-old Norwegian children in two rural communities and compare present values with previous findings.
Methods: Two hundred and fifty-nine 9-year-old children were invited, and 256 participated in this study. Maximal oxygen uptake was directly measured during a continuous progressive treadmill protocol. Body mass and height were also measured.
Results: The mean ± SD relative maximal oxygen uptake was 52.8 ± 6.5 for boys and 46.9 ± 7.2 mL/kg/min for girls. Eight percent of the boys and 16.8% of the girls were classified as overweight, and 1.6% of the boys and 6.9% of the girls as obese. Mean age, body mass, height and Ponderal index were not significantly different between sexes. Girls had a higher BMI than boys (p = 0.05).
Conclusion: Compared to earlier Norwegian studies, children's BMI values seem to have increased substantially. This increase is most pronounced in girls. When assessing these differences using the PI, this increase is less marked. Comparing maximal oxygen uptake data with that in earlier Nordic studies, there is no evidence that fitness has declined among 9-year olds. However, the limitations of the few earlier studies make reliable comparisons difficult.     

A Global Vision of Prehospital Care

Abstract

Background. Out-of-hospital tracheal intubation is controversial because of questions regarding its safety as well as its impact on patient care. Factors contributing to the controversy include failed intubations, number of attempts required, prolonged periods without ventilation, and misplaced tracheal tubes. However, the most important factors are the decision-making and clinical skills of the intubator. Unfortunately, the limited number of outcome studies adds to the controversy. New technology, the video laryngoscope, has been introduced to facilitate tracheal intubation. At least one model of video laryngoscope (GlideScope Ranger) has been designed for out-of-hospital use. In an effort to assess the effect this technology might have on out-of-hospital intubation, a study comparing traditional laryngoscopy (TL) versus video laryngoscopy (VL) was performed. The study endpoint was the number of attempts to achieve intubation. Data were also collected on time to intubate, nonventilated periods, unrecognized misplaced tubes, and complications of the procedure. Methods. Data were collected on 300 consecutive patients, 6 years of age or older, weighing at least 20 kg, who were intubated using TL. They were compared with data on 315 patients who were intubated using VL. All intubations were confirmed by visualization where possible, auscultation, misting, and capnography. In addition, all were continuously monitored by capnography. Results. The average time to intubate in the VL group was 21 seconds (range 8–43 seconds) versus 42 seconds (range 28–90 seconds) in the TL group. The average number of attempts was 1.2 (range 1–3) in the VL group versus 2.3 (range 1–4) in the TL group. Successful intubation was 97%% in the VL group versus 95%% in the TL group. There were no unrecognized misplaced tubes in either group. For failed intubations, an alternative airway was successful in 99%% of the VL group and 99%% of the TL group. Maximum nonventilated time during any one intubation attempt was 37 seconds in the VL group and 55 seconds in the TL group. Conclusions. The numbers of attempts were significantly reduced in the VL group. This suggests that the use of VL has a positive effect on the number of attempts to achieve tracheal intubation.     

In vivo MRI measurements of tumor growth induced by dichloroacetate: implications for mode of action

Dichloroacetate (DCA) is an important by-product of the chlorination of drinking water that produces liver cancer in rodents. Assessment of the risk that results from concentrations that occur in drinking water will be dependent upon the mode of action held responsible for these tumors. A study by Stauber and Bull [Stauber, A.J. and Bull, R. J (1997) Differences in phenotype and cell replicative behavior of hepatic tumors inducted by dichloroacetate (DCA) and trichloroacetate (TCA). Toxicol. Appl. Pharmacol. 144, 235-246] in mice treated with DCA demonstrated a lesion distribution that was skewed towards many small, altered foci of cells that are assumed to be precursor lesions [EPA, (1996). U.S. Environmental Protection Agency: Proposed Guidelines for carcinogen risk assessment; notice. Fed. Reg. 61, pp. 17960-10811]. The present study was designed to determine the extent to which the tumorigenic effects of DCA could be explained by its effect on tumor growth rates (i.e. tumor promoting activity). In vivo magnetic resonance imaging (MRI) allowed accurate determination of growth rates of individual lesions in mice that had been treated with DCA in drinking water at 2 g/l. Out of thirty treated mice, ten were found to have hepatic tumors detectable by MRI at 48 weeks of treatment. These tumor-bearing animals were assigned to two groups matched on the size of lesions observed by in vivo MR1. Treatment with DCA continued in one group of five mice and was stopped in the other. For both groups, tumor growth rates were determined by measuring changes in size of all lesions greater than 1 mm(3) in volume during a 14-day period. Removal of DCA treatment resulted in growth rates that could not be distinguished from zero across all lesion sizes represented in the sample. These data are in agreement with previous observations of DCAs effects on replication rates within tumors (Stauber and Bull, (1997)). Tumor growth rates observed in animals maintained on treatment decreased with lesion volume in a manner that is consistent with a stochastic Gompertz birth-death process proposed by Tan [Tan, W.Y. (1986) A stochastic Gompertz birth-death process. Stat. Prob. Lett. 4, 25-28]. Parameters of this model obtained by fitting measured growth rates were used to predict the lesion-size distribution expected after one year of DCA treatment. The shape of the predicted lesion-size distribution was similar to that observed by Stauber and Bull (Stauber and Bull, (1997)) in mice sacrificed after 40 weeks of DCA treatment. We conclude that the effects of DCA on the division and/or death rates of spontaneously initiated cells can account for the predominance of small lesions in DCA-treated animals.     

Effect of constant light on DMBA mammary tumorigenesis in rats

A study of light, and mammary tumorigenesis was conducted in rats. One-hundred female Sprague-Dawley rats were divided by weight into two groups. One group was exposed to constant light (LL) from 26 days of age, and the second group was exposed to 8 h light and 16 h dark per day (LD). Both groups received an 8 mg dose of a chemical carcinogen, dimethylben-zanthracene (DMBA) at 52 days of age. At 13 weeks post-DMBA, there were significantly fewer mammary tumors in the LL group compared with the LD group. Constant light was clearly demonstrated to have a profound effect on mammary tissue development. Although virgin, the majority of the LL rats (29/50) had gross evidence of lactation at 141 days of age. None of the LD rats (0/50) showed evidence of milk production. These results suggest that constant light not only substantially accelerated mammary gland development, but pushed development of the tissue past the stage normally observed in virgin animals (to the lactation stage).