Effects of lumbopelvic joint manipulation on quadriceps activation and strength in healthy individuals

Lumbopelvic joint manipulation has been shown to increase quadriceps force output and activation, but the duration of effect is unknown. It is also unknown whether lower grade joint mobilisations may have a similar effect. Forty-two healthy volunteers (x+/-SD; age=28.3+/-7.3 yr; ht=172.8+/-9.8 cm; mass=76.6+/-21.7 kg) were randomly assigned to one of three groups (lumbopelvic joint manipulation, 1 min lumbar passive range of motion (PROM), or prone extension on elbows for 3 min). Quadriceps force and activation were measured using the burst-superimposition technique during a seated isometric knee extension task before and at 0, 20, 40, and 60 min following intervention. Collectively, all groups demonstrated a significant decrease (p<0.001) in quadriceps force output without changes in activation (p>0.05) at all time intervals following intervention. The group that received a lumbopelvic joint manipulation demonstrated a significant increase in quadriceps force (3%) and activation (5%) (p<0.05) immediately following intervention, but this effect was not present after the 20 min interval. Since participants in this study were free of knee joint pathology, it is possible that they did not have the capacity to allow for large changes in quadriceps muscle activation to occur.     

Implementing an oral health program in a group prenatal practice

The Rochester Adolescent Maternity Program (RAMP) has incorporated evidence-based oral health guidelines into its prenatal care. These guidelines focus on tracking oral health services, screening and triaging prenatal patients, and providing patient and staff with the education needed to decrease oral health risks to mother, fetus, and baby. The RAMP process serves as a model for promoting quality oral health practices in pregnant teenagers and their babies.     

Predictions of Sediment Toxicity Using Consensus-Based Freshwater Sediment Quality Guidelines

The objectives of this study were to compare approaches for evaluating the combined effects of chemical mixtures on the toxicity in field-collected sediments and to evaluate the ability of consensus-based probable effect concentrations (PECs) to predict toxicity in a freshwater database on both a national and regional geographic basis. A database was developed from 92 published reports, which included a total of 1,657 samples with high-quality matching sediment toxicity and chemistry data from across North America. The database was comprised primarily of 10- to 14-day or 28- to 42-day toxicity tests with the amphipod Hyalella azteca (designated as the HA10 or HA28 tests) and 10- to 14-day toxicity tests with the midges Chironomus tentans or C. riparius (designated as the CS10 test). Mean PEC quotients were calculated to provide an overall measure of chemical contamination and to support an evaluation of the combined effects of multiple contaminants in sediments. There was an overall increase in the incidence of toxicity with an increase in the mean quotients in all three tests. A consistent increase in the toxicity in all three tests occurred at a mean quotient > 0.5, however, the overall incidence of toxicity was greater in the HA28 test compared to the short-term tests. The longer-term tests, in which survival and growth are measured, tend to be more sensitive than the shorter-term tests, with acute to chronic ratios on the order of six indicated for H. azteca. Different patterns were observed among the various procedures used to calculate mean quotients. For example, in the HA28 test, a relatively abrupt increase in toxicity was associated with elevated polychlorinated biphenyls (PCBs) alone or with elevated polycyclic aromatic hydrocarbons (PAHs) alone, compared to the pattern of a gradual increase in toxicity observed with quotients calculated using a combination of metals, PAHs, and PCBs. These analyses indicate that the different patterns in toxicity may be the result of unique chemical signals associated with individual contaminants in samples. Though mean quotients can be used to classify samples as toxic or nontoxic, individual quotients might be useful in helping identify substances that may be causing or substantially contributing to the observed toxicity. An increase in the incidence of toxicity was observed with increasing mean quotients within most of the regions, basins, and areas in North America for all three toxicity tests. The results of these analyses indicate that the consensus-based PECs can be used to reliably predict toxicity of sediments on both a regional and national basis.     

A comparison of isokinetic and isotonic predictions of a functional task

Controversy still exists regarding the use of isokinetic and isotonic exercise in rehabilitation. Many authors have compared these two types of training methods on various strength measures and functional activity, but have used open kinetic chain training. The purposes of this investigation were to determine: 1) which form of closed kinetic chain training, isokinetic or isotonic, would produce the greatest increase in one-legged jump reaction force, and 2) which training method most accurately predicts peak force produced during a one-legged jump. Forty-two legs from 21 female volunteer subjects were used. Each subject had her dominant and nondominant extremities identified, and then each extremity was randomly assigned to either isokinetic training, isotonic training, or control. Both training groups trained using a leg press exercise 3 days a week for 5 weeks, while the control extremities did not train. The isokinetic extremities were trained using a velocity spectrum (two sets of 10 repetitions at each speed: 60 degrees , 180 degrees and 240 degrees /sec) and the isotonic extremities trained using the DAPRE technique. Data were analyzed with an analysis of variance (ANOVA). There was no difference between the three groups for change in one-legged jump force. Both isokinetic and isotonic groups increased strength after training, but these changes did not correlate with changes in one-legged jump reaction force. These results suggest that changes in neither isokinetic force nor isotonic weight lifted developed in a nonweight-bearing closed kinetic chain, directly translate into increased force production during a functional activity.     

Radon concentrations and infiltration rates measured in conventional and energy-efficient houses

To elucidate any connection between high radon concentrations and low-infiltration houses, we have concurrently measured the 222Rn concentration and the infiltration rate in U.S. houses. Three housing surveys have been undertaken: one in "energy-efficient" houses located throughout the U.S. and two in "conventional" houses in the San Francisco area and in Maryland. In each of the groups surveyed, no clear correlation was observed between 222Rn concentrations and infiltration rate, although each parameter varied over a wide range. Infiltration rates for the entire sample, numbering 98 houses, ranged between 0.02 and 1.6 air changes per hr, and 222Rn concentrations ranged from 0.1 to 27 pCi/l. It appears that the major cause of the observed differences in 222Rn concentration is variation from one house to another in the rate at which 222Rn enters houses from its sources.     

Sensory perception of the foot and ankle following therapeutic applications of heat and cold

Many athletes are treated with hot and cold modalities prior to therapeutic exercise, but the effects of these treatments on sensory perception are not clear. The purpose of this study was to examine the effects of hot and cold treatments on sensory perception. We recruited 21 volunteer subjects, who reported for testing on three separate occasions. One of three treatments was applied to the left ankle and foot each day for 20 minutes: cold immersion, hot immersion, or quiet sitting (control). Three variables were measured following treatment: topagnosis, two-point discrimination, and one-legged balance. We assigned treatments and the testing order according to a Greco Latin square. Data were analyzed using a multivariate analysis of variance (MANOVA). No significant differences were detected for the three dependent measures, suggesting that therapeutic applications of heat and cold do not affect sensory perception. These findings indicate that heat and cold applications can be used prior to therapeutic exercise programs without interfering with normal sensory perception as do other analgesic and anesthetic agents. For example, the hypalgesic effect of cold, which is essential to cryokinetics, can be realized without fear of altered sensory perception.     

Antiretroviral drug concentrations and HIV RNA in the genital tract of HIV-infected women receiving long-term highly active antiretroviral therapy.

OBJECTIVE: Our objective was to determine antiretroviral drug concentrations and human immunodeficiency virus (HIV) RNA rebound in cervicovaginal fluid (CVF) in relation to blood plasma (BP) in women receiving suppressive highly active antiretroviral therapy (HAART). METHODS: Thirty-four HIV-infected women who had plasma HIV RNA levels < or =80 copies/mL for at least 6 months were enrolled. Sixty-eight paired CVF and BP drug concentrations and HIV RNA levels were determined before and 3-4 h after drug administration. For each woman and antiretroviral drug, the CVF:BP drug concentration ratios before and after drug administration were calculated. The nonparametric Wilcoxon rank sum test was used to determine if these ratios were different from 1.0. RESULTS: Lamivudine (administered to 20 patients) and tenofovir (administered to 16) had significantly higher concentrations in CVF than in BP before drug administration, with mean CVF:BP concentration ratios of 3.19 (95% confidence interval, 1.2-8.5) and 5.2 (95% confidence interval, 1.2-22.6), respectively. Efavirenz (administered to 13 patients) and lopinavir (administered to 6) had significantly lower concentrations in CVF, with mean CVF:BP concentration ratios of 0.01 (95% confidence interval, 0.00-0.03) and 0.03 (0.01-0.11), respectively. During the study visit (median time after enrollment, 6 months), BP and CVF detectable HIV RNA levels were observed 7 patients (20.6%) and 1 patient (2.9%), respectively. CONCLUSION: Despite lower CVF concentrations of key HAART components, such as efavirenz and lopinavir, virologic rebound was rare. The high concentrations of tenofovir and lamivudine in CVF may have implications for the prevention of sexual transmission during HAART and for pre-exposure or postexposure prophylaxis.