Strategies for the prevention of volleyball related injuries.

Although the overall injury rate in volleyball and beach volleyball is relatively low compared with other team sports, injuries do occur in a discipline specific pattern. Epidemiological research has revealed that volleyball athletes are, in general, at greatest risk of acute ankle injuries and overuse conditions of the knee and shoulder. This structured review discusses both the known and suspected risk factors and potential strategies for preventing the most common volleyball related injuries: ankle sprains, patellar tendinopathy, and shoulder overuse.

The effect of GABA receptor ligands in experimental spina bifida occulta.

BACKGROUND: The pathophysiology behind spina bifida and other neural tube defects (NTDs) is unclear. Folic acid is one variable, but other factors remain. Studies suggest that substances active at the GABA receptor may produce NTDs. To test this hypothesis pregnant rats were exposed to either the GABA a agonist muscimol (1, 2 or 4 mg/kg), the GABA a antagonist bicuculline (.5, 1, or 2 mg/kg), the GABA b agonist baclofen (15, 30, 60 mg/kg), or the GABA b antagonist hydroxysaclofen (1, 3, or 5 mg/kg) during neural tube formation. Normal saline was used as a control and valproic acid (600 mg/kg) as a positive control. The embryos were analyzed for the presence of a spina bifida like NTD. RESULTS: After drug administration the pregnancies were allowed to proceed to the 21st day of gestation. Then embryos were removed and skeletons staining and cleared. Vertebral arch closure was measured. Results indicate that the GABAa receptor agonist muscimol, the GABAa receptor antagonist bicuculline, and the GABAb agonist baclofen produced NTDs characterized by widening of the vertebral arch. Oppositely the GABAb antagonist hydroxysaclofen produced narrowing of the vertebral arches. CONCLUSIONS: The findings indicate that GABA a or b ligands are capable of altering neural formation. GABA may play a greater than appreciated role in neural tube formation and may be important in NTDs. The narrowing of the vertebral arch produced by the GABA b antagonist hydroxysalcofen suggests that GABA b receptor may play an undefined role in neural tube closure that differs from the GABA a receptor.

Valproate enhances N-cadherin production in Xenopus embryos.

Xenopus embryos were exposed to valproate (0, 20, 40, 80 mg/l) either before or after neural tube closure. The embryos were then homogenized and fractionated by gel electrophoresis, and N-cadherin was detected and measured with quantitative immunoblotting. Findings indicated that valproate exposure increased N-cadherin production in a dose-dependent manner. Embryos exposed prior to neural tube closure tended to be more sensitive to the effects of valproate. These findings suggest that alterations in N-cadherin-mediated adhesion or morphogenesis may partially explain the teratogenic mechanism of valproate.

Neurodevelopmental effects of lanthanum in mice.

Mice were exposed to lanthanum chloride in drinking water at 0, 125, 250, and 500 mg/liter concentration prior to conception, during gestation, and until 30 days postnatally. Developing mice were assessed for the development of swimming and walking behavior and ear and eye opening. At 30 days of age the mice were assessed with a standard neurologic scale. Differences were found in the emergence of swimming and walking behavior and ear and eye opening. Differences were also found for touch response and visual placing responses. The brains of lanthanum-exposed mice were also smaller than controls. These findings indicate that lanthanum is a potential behavioral teratogen. Possible mechanisms are discussed.

Gastric retention of zinc-based pennies: radiographic appearance and hazards.

PURPOSE: To determine the radiographic appearance and features of corrosion in U.S. coins exposed to gastric acid. MATERIALS AND METHODS: Six U.S. copper-based pre-1982 pennies, 12 zinc-based post-1982 pennies, a quarter, a nickel, and a dime were exposed to postprandial concentrations of gastric acid (0.15N HCl) for 7 days, and radiographs were obtained daily. Half the zinc-based coins were scraped to disrupt their copper coating. Coins were weighed at the start and completion of the study. RESULTS: Post-1982 zinc-based pennies developed radiolucent corrosive changes within 24 hours. Erosions on the coins became more apparent over time. Frank holes were present on day 2. The weights of these coins decreased 5%-8% during the study. Pre-1982 copper pennies and "silver-colored" coins showed no change on radiographs over 7 days. CONCLUSION: Unexpected radiolucent corrosions may develop in post-1982 zinc alloy pennies when retained in the stomach. Coins have long been considered innocuous foreign bodies in the gastrointestinal tracts of children. However, because of the potential for ulceration and zinc-related morbidity, closer clinical and radiographic observation is warranted. Coins with scalloped edges or holes should be endoscopically removed, as they have likely been retained longer than 1 or 2 days.

Volleyball injuries: managing acute and overuse disorders.

Most volleyball injuries are related to blocking or spiking, both of which involve vertical jumps. The most common acute injuries include ankle and thumb sprains, and common overuse injuries include patellar and shoulder tendinitis, suprascapular neuropathy, and low-back injury. Symptoms will usually resolve with conservative treatment, which may include activity modification, such as reduced jump training or jumping on a sand surface, and technical instruction. Players who have significant symptoms from suprascapular neuropathy may require diagnostic electromyography and MRI before surgical decompression.

Comparison of the behavior of the curly tail and CBA mouse on a neurologic scale.

ct/ct mice are a mutation of the CBA strain with a high incidence of spina bifida (SB). Because humans with SB can exhibit abnormal behavior, we compared ct/ct and CBA mice using a neurologic assessment tool. ct/ct mice are more active and engage in more climbing, and stereotypical and compulsive behavior. When stimulated during cage removal ct/ct mice react more vigorously. ct/ct mice react more vigorously to a novel stimulus, and will vigorously search for a stable surface during visual placement. In the open field ct/ct mice crossed more lines and reared more than CBA. ct/ct mice demonstrated deficient performance in a modified Morris water maze. No differences were noted for other behaviors tested. The results argue that the mutation that produces SB in ct/ct mice also alters brain structure or chemistry. This is consistent with the findings in humans where SB can produce a variety of behavioral anomalies, most notably hyperactivity, attentional disorders, learning disabilities, and developmental lags.

Common injuries in volleyball. Mechanisms of injury, prevention and rehabilitation.

Volleyball has become an extremely popular participation sport worldwide. Fortunately, the incidence of serious injury is relatively low. The sport-specific activity most commonly associated with injury is blocking. Ankle sprains are the most common acute injury. Recurrent sprains may be less likely to occur if an ankle orthosis is worn. Patellar tendinitis represents the most common overuse injury, although shoulder tendinitis secondary to the overhead activities of spiking and serving is also commonly seen. An unusual shoulder injury involving the distal branch of the suprascapular nerve which innervates the infraspinatus muscle has been increasingly described in volleyball players in recent years. Hand injuries, usually occurring while blocking, are the next most common group of injuries. Fortunately, severe knee ligament injuries are rare in volleyball. However, anterior crutiate ligament injury is more likely to occur in female players. Many of these injuries may be preventable with close attention to technique in sport-specific skills and some fairly simple preventive interventions.

A comparison of intraoral antimicrobial effects of stabilized stannous fluoride dentifrice, baking soda/peroxide dentifrice, conventional NaF dentifrice and essential oil mouthrinse.

The intraoral antimicrobial activity of four commercial oral products-conventional NaF dentifrice (Crest), baking soda/peroxide/NaF dentifrice (Mentadent), essential oil mouthrinse (Listerine) and SnF2 dentifrice (Crest Plus Gum Care)-have been compared in three test regimens. Formulations were compared for their ability to suppress the regrowth and apical extension of dental plaque following toothbrushing during thirty hours of non-brushing where products were used as oral rinses (30-hour plaque regrowth model). Formulations were also compared for their ability to suppress the colony-forming units (cfu) of facultative anaerobic bacteria sampled from buccal gingival surfaces following use (Gingival Surface Microbial Index-GSMI model). Lastly, formulations were compared for effects in suppressing the glycolytic metabolic activity and regrowth activity of in vivo-treated dental plaques sampled at various periods following topical use and incubated under controlled ex vivo conditions (Plaque Glycolysis and Regrowth-PGRM model). In thirty-hour plaque regrowth testing, the rank ordered antimicrobial efficacy of formulations followed SnF2 > essential oils > NaF = water = baking soda/peroxide. In GSMI testing, all formulations were shown to suppress the cfu of facultative anaerobic bacteria relative to baseline, although SnF2 treatment was observed to reduce bacterial levels to a significantly greater degree than NaF dentifrice or baking soda/peroxide dentifrice up to two hours following brushing. In PGRM testing, the SnF2 dentifrice provided significant inhibition of bacterial metabolism and regrowth following topical application when compared with the NaF dentifrice as control. The baking soda/peroxide dentifrice provided no reduction in either bacterial metabolism or regrowth in PGRM. Previous studies had demonstrated modest effects for essential oil rinse in reducing PGRM plaque regrowth, with no effects for this treatment on plaque metabolism. Overall, these results demonstrate that SnF2 dentifrice provides substantial intraoral antimicrobial effects. The essential oil mouthrinse also exhibits significant intraoral antimicrobial effects, albeit apparently less than SnF2 dentifrice. The baking soda/peroxide dentifrice did not produce any antimicrobial effects following in vivo use compared with conventional dentifrice. These results provide mechanistic rationale for the chemotherapeutic efficacy of SnF2 and essential oil formulations in reducing gingivitis, while providing no support for the expectation of clinical efficacy for formulations containing baking soda and peroxide.

Neck injuries: urgent decisions and actions.

When a neck injury is suspected, the on-site physician must first provide basic trauma care, which includes establishing an airway as necessary, assessing breathing, and checking circulation and neurologic compromise. A few targeted questions during history taking and a directed physical exam will help rule out serious cervical injuries, which are uncommon. More common are minor injuries, such as "burners." Team physicians must also be well-versed in immobilizing and transporting the patient, administering a thorough neurologic exam, and establishing when the athlete can return to competition.

Arnold-Chiari-like malformation associated with a valproate model of spina bifida in the rat.

The brains of rat fetuses exposed to saline and valproic acid (VA: 600 mg/kg or 1,200 mg/kg) at 10 days of gestation were examined for structural changes similar to that seen for the Arnold-Chiari malformation (ACM) in humans. Only fetuses exposed to the 1,200-mg/kg level VA demonstrated spina bifida (SB) type widening of the vertebral arch when compared to saline treated animals. When compared to controls, both 600-and 1,200-mg/kg VA animals demonstrated microencephaly. The brains of treated animals demonstrated alterations in their angular morphology such that the cerebellum was displaced toward the foramen magnum in a manner akin to human ACM. These findings indicate that valproate-induced SB in the rat more closely approximates SB in humans than was previously appreciated and provides a model for experimental study of both SB and ACM.

Corticosteroid injection therapy for overuse injuries.

Local corticosteroid injection therapy may be considered for many conditions commonly treated by the primary care physician. Chronic overuse and flawed biomechanics may lead to inflammation in areas easily accessible to injected local corticosteroids, including bursae, tendon sheaths and joints. It is generally preferable to mix the steroid preparation with an anesthetic agent to minimize the injection pain, provide immediate symptom relief and confirm the diagnosis. Local complications of corticosteroid injection include tendon and ligament weakening, bacterial infections of joints and related structures, and subcutaneous tissue atrophy. Systemic complications are rare but reportedly include hyperglycemia and adrenal axis suppression.

A behavioral nosology for tinnitus.

Studies of the physiological and psychological characteristics of tinnitus and its treatment have yielded a variety of conclusions. The variation in results may reflect heterogeneous patient populations. Although the sources of variation are many, one may be derived from combining patients of several severities of tinnitus into a single group. A nosology is proposed for tinnitus severity to be classified by the patient's behavioral responses. Classifying patients allows direction to specific treatment modalities and will facilitate research. The concept of phantom auditory pain and a rational basis for the use of antidepressant therapy are discussed.

Athlete age and sports physical examination findings.

BACKGROUND: Interscholastic and intercollegiate athletes commonly visit physician offices to have sports participation examinations (PPEs). Few data exist, however, to help determine the age range for which such examinations are reasonable. The purpose of this study was to determine the percentage of athletes with significant findings on sports PPEs among junior high school, high school, and college-age athletes. METHODS: Analyses were made of 937 consecutive PPEs that were performed by primary care physicians using a standardized form. Subjects were interscholastic athletes of junior high, high school, and college age. Significant findings were defined as those that resulted in any recommendation, ie, change in management, by the examining physician. RESULTS: The incidence of significant findings was 3.4% for the junior high school athletes, 15.4% for high school athletes, and 33.9% for college athletes (P < .001). The overall percentage of athletes disqualified from participating in any sport, which was 1.7%, did not differ significantly across age levels. CONCLUSIONS: In this sample, college and high school athletes were much more likely than junior high school athletes to have significant findings on sports. PPEs. These data cast uncertainty on the necessity of annual PPEs to screen athletes of junior high school age.

Comparative antimicrobial effectiveness of a substantive (0.12% chlorhexidine) and a nonsubstantive (phenolic) mouthrinse in vivo and in vitro.

Antimicrobial mouthrinses can play an important role in maintaining oral health by killing cariogenic organisms and preventing plaque and gingivitis. The active ingredients are adsorbed by oral tissues and then gradually released into the saliva. In this article, the effectiveness of a substantive chlorhexidine and a nonsubstantive phenolic antimicrobial mouthrinse were tested. When compared, the results indicated that the two types of mouthrinses are equally effective at killing salivary microbes for up to 30 minutes after rinsing. The prescriptive substantive rinse, however, continued its microbicidal effect for a longer duration (up to 5 hours) than the over-the-counter nonsubstantive rinse. The substantive rinse showed pronounced and measurable zones of inhibition around each well in the agar diffusion assay where the nonsubstantive rinse showed no zone around any well at any time. The substantive rinse also showed a superior ability to inhibit the growth of 28 oral microbes, including some putative periodontopathogens, which were assayed.

Reduction of oral microbes by a single chlorhexidine rinse.

Because of the continued threat of human immunodeficiency virus and hepatitis B infection, as well as the possibility of cross-infection from microbes, such as the herpesviruses and staphylococci, infection control remains a critical issue in dentistry. A traditional response to the infection-control issue is the use of barrier protection by the practitioner and staff. Little attention has been paid to reducing the number of potential pathogens in the oral cavity before dental procedures as a means of minimizing the potential spread of contagion between patients and treatment providers. A study to determine the effectiveness and duration of a single rinse with 0.12% chlorhexidine gluconate oral antiseptic in reducing the number of microorganisms in the oral cavity is presented.

A scanning electron microscope study of the human cervical lymph node.

Arterial casts of human cervical lymph nodes were studied using scanning electron microscopy. Human cervical lymph nodes appear to be much more complex and dense than their animal counterparts. Human lymph nodes have a separate medulla arising from the hilar artery complex and cortical structure derived from capillaries. Also present is a previously unknown rosette formation of blood vessels. The possible implications of these findings for inflammatory and neoplastic diseases are discussed.