Use of skin and blood as nonlethal indicators of heavy metal contamination in northern water snakes (Nerodia sipedon).

Relatively little is known about contaminants in reptiles, particularly snakes. The concentrations of arsenic, cadmium, chromium, lead, manganese, mercury, and selenium were examined in blood and skin of 46 northern water snakes (Nerodia sipedon) in Tennessee and correlated with concentrations in internal tissues (liver, kidney, muscle) to determine if blood or skin could serve as a nonlethal indicator of internal metal exposure or body burden. Snakes were collected from the East Fork Poplar Creek (EFPC) within the United States Department of Energy's Y-12 National Security Complex (part of the Oak Ridge National Laboratory) and from a reference stretch of the Little River in East Tennessee. For blood, the only consistent positive correlations with internal organs were for mercury, and correlations were low except for muscle. Skin showed significant positive correlations with all three organs for mercury, chromium, selenium, and lead. For manganese and cadmium, skin level was positively correlated with liver level. Blood generally reflects recent exposure, not necessarily body burden, but in water snakes it correlates with body burden for mercury. Skin proved useful for more metals, although patterns were not necessarily consistent across sex and locality subgroups. The most consistent pattern was for mercury, the metal of greatest concern in many aquatic ecosystems, including EFPC.

Heavy metal concentrations in northern water snakes (Nerodia sipedon) from East Fork Poplar Creek and the Little River, East Tennessee, USA.

We compared the levels of arsenic, cadmium, chromium, lead, manganese, mercury, and selenium in the blood, kidney, liver, muscle, and skin of northern water snakes (Nerodia sipedon) collected from the upper reach of East Fork Poplar Creek (EFPC) within the United States Department of Energy's (USDOE's) Y-12 National Security Complex with concentrations in tissues of northern water snakes from a reference reach of the Little River downstream from the Great Smoky Mountains National Park in East Tennessee. Our objectives were to determine whether concentrations of these metals were higher in tissues of water snakes collected from EFPC compared with the reference site and if northern water snakes were suitable bioindicators of metal contamination. Except for chromium, metal levels were significantly higher in tissues (kidney, liver, muscle, and skin) of EFPC northern water snakes compared with those in tissues of snakes from the reference site. Although female northern water snakes were significantly larger than male snakes, their tissues did not contain significantly higher metal concentrations compared with those from male snakes, possibly because of maternal transfer of metals to eggs. This study was the first to examine the accumulation of contaminants resulting from the operations of the USDOE's Oak Ridge Reservation in snakes.

The accumulation and effects of environmental contaminants on snakes: a review.

In any ecological risk assessment, a full complement of the relevant members of the ecosystems being studied should be considered. Reptiles in general, and snakes in particular, are important although often neglected components of terrestrial and aquatic ecosystems and should be included in any study on environmental contamination. By neglecting reptiles, the risks posed by a particular contaminant cannot be fully assessed. Since all snakes are secondary, tertiary, and top predators, they are susceptible to the bioaccumulation of environmental contaminants. Their unique life histories make their roles in food webs diverse and important, and they are crucial to the proper functioning of many ecological processes. We review and summarize organic and inorganic contaminant and radionuclide/radiation residue and lethal and sublethal effects data for snakes to stress the importance of snakes and encourage their inclusion in ecological risk assessments, to demonstrate the paucity of available contaminant data on snakes and reveal the main information gaps, to encourage further ecotoxicological studies on snakes, and to facilitate the use of existing snake contaminant data in ecological risk assessments. This review is the most comprehensive review currently available on the effects on and accumulation of environmental contaminants in snakes.

Congenital agenesis of the right pulmonary artery.

A 44-year-old woman with recurrent pulmonary infections developed severe hemoptysis. Chest radiography revealed a hypoplastic right lung. Absence of the right pulmonary artery, a very rare congenital anomaly, was demonstrated by computed tomography and cardiac catheterization. Severe pulmonary hypertension in the contralateral lung precluded right pneumonectomy but percutaneous embolization of a large systemic arterial collateral to the right lung provided palliative relief of hemoptysis.

The use of glycoprotein IIb/IIIa inhibitor therapy in acute ST-segment elevation myocardial infarction: current practice and future trends.

The goal of therapy in acute myocardial infarction is complete and timely restoration of coronary blood flow. Current strategies for reperfusion fail to achieve ideal results and resolution of ischemia in all patients. The platelet plays a pivotal role in the pathophysiology of an acute myocardial infarction, and antiplatelet therapy has been shown to improve clinical outcomes. The final common pathway for platelet activation and aggregation in acute myocardial infarction is the activation of the glycoprotein (GP) IIb/IIIa receptor. Newer reperfusion strategies target the GP IIb/IIIa receptor, thereby preventing the prothrombotic effects of platelets in an acute myocardial infarction. In the past decade, several strategies targeting the use of GP IIb/IIIa inhibitors have been evaluated. GP IIb/IIIa inhibitors have been shown to improve angiographic Thrombolysis in Myocardial Infarction (TIMI) 3 flow rates when used as reperfusion therapy given with heparin and aspirin as compared with heparin and aspirin alone. When GP IIb/IIIa inhibitors are used with full-dose fibrinolytics, early studies have suggested a trend toward more rapid and more complete reperfusion in an acute myocardial infarction. Later trials have examined the use of GP IIb/IIIa inhibitors in conjunction with reduced-dose fibrinolytics. Results from TIMI 14 and Global Use of Strategies to Open occluded arteries-IV pilot trials support the use of combination therapy with reduced- dose fibrinolytics and the GP IIb/IIIa inhibitor abciximab. Given the promising role of GP IIb/IIIa inhibitor therapy in acute myocardial infarction, investigators questioned the need for concomitant antithrombin therapy. However, data from several investigations suggest that antithrombin therapy is required when GP IIb/IIIa inhibitors are used with fibrinolytics, although it appears that the dose of heparin may be reduced. Finally, recent investigations have addressed the safety and efficacy of facilitated early percutaneous intervention. In this strategy, patients presenting with an acute myocardial infarction are treated with reduced-dose fibrinolytics and GP IIb/IIIa inhibitors and are taken to the interventional cardiac catheterization laboratory within the first 60 minutes of therapy.

Lizard contaminant data for ecological risk assessment.

This review is the most comprehensive currently available of the effects and accumulation of environmental contaminants on lizards. The importance of lizards was emphasized in hope that they be included in ecological risk assessments as well as any study on environmental contamination. Some studies presented here indicated that lizards are ideal bioindicators. They are important as a component of biodiversity, and many species are listed as threatened or endangered. In addition, lizards are a significant part of many ecosystems as well as an important link in many food chains. There are large gaps in data for many environmental contaminants, particularly data on lizards. Ecotoxicological studies on a wide variety of lizard species are needed; both laboratory and field studies would provide useful information. Because the majority of lizards are insectivores, studies of the effects and accumulation of pesticides are essential. A few current studies are available from Africa and Australia, but most, especially those conducted in the U.S., were not current. Studies are needed on the effects and accumulation of ubiquitous contaminants, such as heavy metals and PCBs. Because of the many contaminated sites and the significant waste disposal problem, studies are needed on the effects and accumulation of radionuclides on lizards. Furthermore, effects of multiple stressors must be studied. Last, studies are needed linking the effects of contaminants to tissue residues. It is hoped that the convenience of having the vast majority of lizard environmental contaminant data available in one document will encourage its use.

Upper extremity physical factors affecting tennis serve velocity.

Forty tournament-level tennis players with expert serve technique volunteered to have their serve evaluated to determine relationships between anthropometric data, extremity strength, and functional serve velocity. All players underwent a complete physical examination, a video taped serve analysis, a radar measurement of serve velocity, and a series of upper extremity strength measurements. Statistical analysis was performed to determine which factors were related to serve velocity. Statistically significant relationships were found between serve velocity and several flexibility measurements including increased dominant wrist flexion (P < 0.05), increased dominant shoulder flexion (P < 0.05), and increased dominant shoulder internal rotation at 0 degrees of abduction (P < 0.05). Several strength measurements were also related to serve velocity including elbow extension torque production (P < 0.01) and the ratios of internal to external rotational torque production for both low- and high-speed measurements (P < 0.01 concentrically and P < 0.05 eccentrically). These findings relate strength and flexibility to serve velocity, suggesting that it may be possible to increase a tennis player's serve velocity through specifically directed muscular strengthening or stretching regimens. However, prospective studies must be undertaken to demonstrate these possibilities.

Intraneural ulnar nerve pressure changes related to operative techniques for cubital tunnel decompression.

To evaluate the effect of critical anatomic structures on the ulnar nerve after cubital tunnel decompression, we determined the intraneural ulnar nerve pressure in 50 fresh cadavers after the following surgical procedures: simple decompression, medial epicondylectomy, subcutaneous transposition, and submuscular transposition by the Learmonth and by the musculofascial lengthening technique. Intraneural pressure was measured in 0 degrees, 30 degrees, 60 degrees, and 90 degrees elbow flexion at locations that were proximal, within, and distal to the cubital tunnel. Statistical analysis compared the mean change in intraneural pressure between the "postoperative" and the baseline "preoperative" pressure measurements for the different surgical strategies. While both the simple decompression and the medial epicondylectomy had significantly lower intraneural pressures than the Learmonth or the subcutaneous transposition, each of these four techniques resulted in elevated intraneural pressures. The musculofascial lengthening technique for submuscular transposition was the only surgical strategy that reduced intraneural ulnar pressure at each site of measurement and for all degrees of elbow flexion, this reduction of pressure being significant in comparison with the other surgical techniques.

Isokinetic concentric versus eccentric training of shoulder rotators with functional evaluation of performance enhancement in elite tennis players.

Thirty elite tennis players were randomly assigned to three groups to evaluate shoulder isokinetic internal and external rotation training: an isokinetic concentric group, an isokinetic eccentric group, and a control group with no training. Subjects were tested before and after training both concentrically and eccentrically using an isokinetic dynamometer. Functional output before and after training was assessed by the average and peak velocity of six maximal serves. The effect of training on serve velocity endurance was also assessed. Statistically significant concentric and eccentric strength gains (11%) were obtained in both training groups when compared with controls (decreased total average strain of 2%) (P < 0.0004). Serve velocity increased by greater than 11% in both training groups, which was a significant increase from the average of 1% in the control group (P < 0.0001). In the endurance study, training group subjects displayed a tendency to maintain their serve velocity (loss of approximately 2%) greater than controls (loss of 6.4%) (P < 0.05). Isokinetic training led to increases in objective and functional output in elite tennis players. This training regimen may have significance in the final stages of the rehabilitation of injured shoulders as well as in improved performance and reduced injury risk.

Electromyographic study of the anterior cruciate ligament-hamstrings synergy during isometric knee extension.

The purpose of this investigation was to determine the role the hamstrings group may play in augmenting passive articular mechanisms during activity in which anterior drawer force may detrimentally affect the anterior cruciate ligament (ACL). Nine male subjects performed non-weight-bearing isometric knee extension at 10% increments of maximum voluntary contraction (MVC). Electromyographic (EMG) signals were detected and recorded from the vastus lateralis, vastus medialis oblique, vastus medialis longus, and the long head of the biceps femoris. The EMG signals were rectified and integrated over 1000 ms and normalized to subject-specific values. The data were subjected to a repeated-measures analysis of variance. The results demonstrated that expected significant increases in quadriceps excitation accompanied increases in knee extensor torque. Hamstrings excitation was not found to change significantly (total change = 3.4%). It was concluded that functionally adequate knees do not require posterior drawer force in excess of that provided passively by articular structures.

Effects of fatigue on activation profiles and relative torque contribution of elbow flexor synergists.

The purpose of this study was to examine changes in elbow flexion synergies as a result of fatigue. Subjects performed a series of five isometric contractions at 10% maximum voluntary contraction step intervals. Pre- and post-fatigue surface electromyograms for the muscles were rectified, integrated, normalized, a representative equation determined using the least-squares method, and the equations numerically differentiated. The differentiated curves represent the change of excitation (and therefore, change of isometric torque) with respect to the change in resultant torque (dIEMG/dT). Pre-fatigue synergy, as indicated by the dIEMG/dT, was characterized by both co-activation and trade-off patterns. The nature of the synergy was changed as a result of fatigue. This technique, focusing upon synergistic patterns, quantifies differences in excitation profiles in a manner not previously described.

Resultant tennis ball velocity as a function of off-center impact and grip firmness.

The relationship between resistance to rotation about the longitudinal axis of a tennis racquet and post-impact ball velocity following off-center hits was investigated. Two conditions simulating the extremes of grip firmness (zero vs maximal) were compared. Tennis balls were released manually from a platform onto the racquet face from a height of 5.75 m and impacted at 10.62 m . s-1. Forty-one trials were filmed at 175 frames . s-1 and were digitized electronically. Results were subjected to a multivariate analysis of covariance (MANCOVA) using transverse and longitudinal distances between the point of impact and the geometric center of the racquet face as covariates. MANCOVA results indicated no significant differences between post-impact ball velocity for the two conditions. Therefore, it was concluded that previously reported concepts regarding striking mass and grip rigidity are no longer tenable and that the influence of grip firmness in activities in which hand-held implements are used is important only in terms of post-impact implement control. Potential adverse physiological/anatomical effects related to over-gripping are suggested.