Comparison of lower limb stiffness between male and female dancers and athletes during drop jump landings

Repetition of jumps in dance and sport training poses a potential injury risk; however, non‐contact landing injuries are more common in athletes than dancers. This study aimed to compare the lower limb stiffness characteristics of dancers and athletes during drop landings to investigate possible mechanisms of impact‐related injuries. Kinematics and kinetics were recorded as 39 elite modern and ballet dancers (19 men and 20 women) and 40 college‐level team sport athletes (20 men and 20 women) performed single‐legged drop landings from a 30‐cm platform. Vertical leg stiffness and joint stiffness of the hip, knee, and ankle were calculated using a spring‐mass model. Stiffness data, joint kinematics, and moments were compared with a group‐by‐sex 2‐way analysis of variance. Multiple linear regression was used to assess the relative contribution of hip and knee and ankle joint stiffness to variance in overall vertical leg stiffness for dancers and athletes. Dancers had lower leg (P < 0.001), knee joint (P = 0.034), and ankle joint stiffness (P = 0.043) than athletes. This was facilitated by lower knee joint moments (P = 0.012) and greater knee (P = 0.029) and ankle joint (P = 0.048) range of motion in dancers. Males had higher leg (P < 0.001) and ankle joint stiffness (P < 0.001) than females. This occurred through lower ankle range of motion (P < 0.001) and greater ankle moment (P = 0.022) compared to females. Male and female dancers demonstrated reduced lower limb stiffness compared to athletes, indicating a more pliable landing technique. Dance training techniques could potentially inform approaches to injury prevention in athletes.     

Total and free disopyramide by fluorescence polarization immunoassay and relationship between free fraction and alpha-1 acid glycoprotein

Disopyramide is an antiarrhythmic drug with concentration dependent protein binding within the therapeutic range. We found good agreement between fluorescence polarization immunoassay (FPIA, Abbott TDX) and high performance liquid chromatography (HPLC) for total disopyramide among 27 admission patients' sera (FPIA = 1.12 (HPLC) -0.002, r = 0.982, SEE = 0.378 mg/l). Agreement between FPIA and HPLC for free disopyramide was similarly good (FPIA = 0.867 (HPLC) -0.003, r = 0.986, SEE = 0.09 mg/l, n = 27). Serum alpha 1 acid glycoprotein concentration (AAG) and free fraction (FF) percent of disopyramide correlated inversely (FF = -0.0112 (AAG) + 31.3 r = 0.707, SEE = 6.41 mg/l, n = 24), and the free disopyramide fraction varied greatly. For two pooled sera with 12 different disopyramide concentrations (range from 0.5-20.0 mg/l), the proportion of free fraction ranged from 6.5 to 73.2%. Overall, we found the free disopyramide fraction variable with each individual, total drug, and protein concentration. Therefore, free drug concentration should be monitored in disopyramide therapy, and FPIA is reliable for free as well as total drug assay.     

Biopsy-related hemorrhage of renal allografts treated by percutaneous superselective segmental renal artery embolization

INTRODUCTION: Biopsy-related vascular injuries in renal transplants are rare, but they can lead to dramatic clinical symptoms prompting immediate treatment. Transcatheter embolization is a minimally invasive technique used to treat some forms of arterial bleeding. This study evaluated the efficacy of this technique in iatrogenic biopsy-related vascular lesions in renal allografts. MATERIALS AND METHODS: Over the last eight years, six patients with severe renal hemorrhage were admitted to the angiography department of our hospital for evaluation and possible further treatment. All of them had a history of previous biopsy of a transplanted kidney. They all presented with clinical signs of hemodynamic instability. Angiographic investigation of the kidneys preceded further intervention in all cases. All underwent hyperselective embolization of the specific bleeding vessel with the use of microcoils and/or gelfoam particles. RESULTS: Successful embolization of the feeding artery could be performed in all patients. Superselective segmental renal artery embolization had a successful outcome concerning a steady renal function and a stable clinical course. No complications occurred. CONCLUSION: Transcatheter embolization is a safe and efficient endovascular technique to treat biopsy-related vascular injuries in renal transplants. Immediate clinical success and significant benefit in renal function can be obtained, and the longevity of the allograft after successful embolization mainly depends on the natural outcome.     

Visual evoked potentials in a rabbit model of hepatic encephalopathy. I. Sequential changes and comparisons with drug-induced comas

The recording of visual evoked potentials in rabbits has been shown to be an objective, reproducible, noninvasive technique for quantitating changes in the pattern of cerebral neuronal activity. The development of hepatic encephalopathy due to galactosamine-induced fulminant hepatic failure was consistently associated with a series of distinctive changes in the visual evoked potential waveform. The pattern of the visual evoked potential in hepatic coma (due to galactosamine-induced fulminant hepatic failure) differed fundamentally from that in ether-induced coma, but was identical to that in comas induced by three drugs which activate gamma-aminobutyric acid-ergic neural mechanisms: pentobarbital, diazepam, and muscimol. These findings are compatible with activation of the gamma-aminobutyric acid inhibitory neurotransmitter system contributing to cerebral neuronal inhibition in hepatic coma due to galactosamine-induced fulminant hepatic failure.     

Visual evoked potentials in a rabbit model of hepatic encephalopathy. II. Comparison of hyperammonemic encephalopathy, postictal coma, and coma induced by synergistic neurotoxins

To assess neuronal mechanisms of potential importance in the pathogenesis of hepatic encephalopathy, visual evoked potentials were recorded in rabbits with acute hyperammonemic encephalopathy, postictal coma, and toxin-induced coma resulting from the administration of a combination of subcoma doses of three neurotoxins: ammonia, dimethyldisulfide, and octanoic acid. The patterns of visual evoked potentials in these three syndromes were compared with those of rabbits with hepatic encephalopathy due to galactosamine-induced fulminant hepatic failure. In the absence of seizures, the patterns of visual evoked potentials associated with hyperammonemic encephalopathy and toxin-induced coma were fundamentally different from those associated with any stage of hepatic encephalopathy due to galactosamine-induced fulminant hepatic failure. In contrast, the pattern of visual evoked potentials in early postictal coma induced by four different precipitating factors (including toxin-induced seizures) resembled that of late-stage hepatic encephalopathy due to galactosamine-induced fulminant hepatic failure. These findings suggest that the recording of visual evoked potentials may be of value in experimentally testing hypotheses of the pathogenesis of hepatic encephalopathy due to fulminant hepatic failure. They indicate that acute hyperammonemia is not a satisfactory model of hepatic encephalopathy due to galactosamine-induced fulminant hepatic failure, that the occurrence of seizures may lead to incorrect interpretation of experimental data from models of hepatic encephalopathy, and that the syndromes of hepatic encephalopathy due to galactosamine-induced fulminant hepatic failure and postictal coma may share similar neural mechanisms. Finally, the results of this study do not support the hypothesis that hepatic encephalopathy due to galactosamine-induced fulminant hepatic failure is mediated by the synergistic interaction of ammonia, mercaptans, and fatty acids on the brain.     

Inter- and intrarater reliability in computed axial tomographic grading of splenic injury: why so many grading scales?

OBJECTIVE: After splenic trauma, critical decisions regarding operative intervention are often made with the aid of computed axial tomographic (CT) scan findings. No CT scan-based grading scale has been demonstrated to predict accurately which patients require operative or radiologic intervention for their splenic injuries. We hypothesized that use of the most common grading scale, the American Association for the Surgery of Trauma scale, would be associated with low intra- and interreliability scores. We assessed the ability of experienced trauma radiologists to differentiate grade III from grade IV splenic injuries. METHODS: The films of patients who had undergone abdominal CT scanning before splenectomy for grade III or IV injuries were serially evaluated by four trauma radiology faculty weekly for 3 weeks. We assessed intra- and interrater reliability for grading and for presence of contrast blush. RESULTS: Intrarater reproducibility yielded a weighted kappa score of 0.15 to 0.77. Interrater reliability weighted kappa scores ranged from 0 to 0.84, with a mean value of 0.23. CONCLUSION: CT imaging is not reliable for identifying grades III and IV splenic injury, as experienced radiologists often underestimate the magnitude of injury. Interrater reliability is poor. Factors other than the CT grade of splenic injury should determine whether patients require operative or angiographic therapy.     

Urgent superselective segmental renal artery embolization in the treatment of life-threatening renal hemorrhage

INTRODUCTION: Renal hemorrhage is a major life-threatening condition that can be caused by trauma, operation, biopsy, as well as sudden spontaneous rupture of renal tumors or aneurysms. We report our experience with superselective segmental renal artery catheterization and embolization as therapeutic options for such cases. PATIENTS AND METHODS: Over the last 8 years, 28 patients with severe renal hemorrhage were admitted for evaluation and possible further treatment. Twenty of them had a history of previous biopsy (6 of them one of a transplanted kidney), 1 patient had a recent percutaneous nephrostomy, 4 patients presented with renal mass ruptures (2 patients renal cell carcinoma, 1 patient angiomyolipoma, 1 patient hemorrhagic cysts), 1 patient had rupture of a renal aneurysm during delivery, 1 patient suffered bleeding after partial nephrectomy, and 1 patient was hospitalized after a car accident. They all presented with clinical signs of hemodynamic instability. Angiographic investigation of the kidneys preceded further intervention in all cases. 26 out of the 28 patients underwent superselective embolization of the specific bleeding vessel with the use of microcoils and/or Gelfoam particles. RESULTS: All patients treated by superselective segmental renal artery embolization had a successful outcome, including a steady renal function and a stable clinical course. No complications occurred. CONCLUSION: Superselective segmental renal artery catheterization and embolization is a safe and efficient method for the treatment of patients with severe renal hemorrhage, preserving healthy renal parenchyma and renal function.     

Targeted caricatures

The original Vanity Fair was an English weekly magazine from 1868 to 1914. It offered its readers articles on fashion, current events, reviews of the theater, new books, reports on social events (and the latest scandals), and other trivia. Today, the old Vanity Fair is best known for its glorious caricature prints. Over 2,000 of these caricatures were printed, varying on at least 67 subjects. One category, doctors and scientists, presents four otolaryngologists. These four well known personalities will be presented with their satirical biographies, along with a brief historical account for each of their life after Vanity Fair. Laryngoscope, 2009     

Evidence that methylphenidate enhances the saliency of a mathematical task by increasing dopamine in the human brain

OBJECTIVE: Methylphenidate is the most commonly prescribed drug for attention deficit hyperactivity disorder (ADHD), yet its therapeutic mechanisms are poorly understood. The objective of this study was to assess if methylphenidate, by increasing dopamine (neurotransmitter involved in motivation) in brain, would enhance the saliency of an academic task, making it more interesting. METHOD: Healthy subjects (N=16) underwent positron emission tomography with [(11)C]raclopride (dopamine D(2) receptor radioligand that competes with endogenous dopamine for binding) to assess the effects of oral methylphenidate (20 mg) on extracellular dopamine in the striatum. The authors compared the effects of methylphenidate during an academic task (solving mathematical problems with monetary reinforcement) and a neutral task (passively viewing cards with no remuneration). In parallel, the effects of methylphenidate on the interest that the academic task elicited were also evaluated. RESULTS: Methylphenidate, when coupled with the mathematical task, significantly increased extracellular dopamine, but this did not occur when coupled with the neutral task. The mathematical task did not increase dopamine when coupled with placebo. Subjective reports about interest and motivation in the mathematical task were greater with methylphenidate than with placebo and were associated with dopamine increases. CONCLUSIONS: The significant association between methylphenidate-induced dopamine increases and the interest and motivation for the task confirms the prediction that methylphenidate enhances the saliency of an event by increasing dopamine. The enhanced interest for the task could increase attention and improve performance and could be one of the mechanisms underlying methylphenidate's therapeutic effects. These findings support educational strategies that make schoolwork more interesting as nonpharmacological interventions to treat ADHD.