The acute influence of amateur boxing on dynamic cerebral autoregulation and cerebrovascular reactivity to carbon dioxide.

PURPOSE: The purpose of this study was to investigate the acute effect of head impacts, sustained over the course of three rounds of amateur boxing, on indices of cerebrovascular function. METHODS: Eighteen university amateur boxers (six female) completed three experimental trials in a randomised order; (1) three rounds of boxing (BOX), (2) an equivalent bout of pad boxing (where no blows to the head were sustained; PAD), and (3) a time-matched seated control trial (CON). Indices of cerebrovascular function were determined immediately before and 45 min after each trial. Specifically, dynamic cerebral autoregulation (dCA) was determined by considering the relationship between changes in cerebral blood velocity and mean arterial pressure during 5 min of squat-stand manoeuvres at 0.05 and 0.10 Hz. Cerebrovascular reactivity was determined using serial breath holding and hyperventilation attempts. RESULTS: Participants received an average of 40 ± 16 punches to the head during the BOX trial. Diastolic, mean and systolic dCA phase during squat stand manoeuvres at 0.05 Hz was lower after BOX compared to pre BOX (P ≤ 0.02, effect size (d) ≥ 0.74). No other alterations in dCA outcomes were observed at 0.05 or 0.10 Hz. The number of head impacts received during the BOX trial was associated with the change in systolic phase (r = 0.50, P = 0.03). No differences in cerebrovascular reactivity to breath holding or hyperventilation were observed. CONCLUSIONS: A typical bout of amateur boxing (i.e., three rounds) can subtly alter cerebral pressure-flow dynamics, and the magnitude of this change may be related to head impact exposure.

4D flow magnetic resonance imaging in bicuspid aortic valve disease demonstrates altered distribution of aortic blood flow helicity.

PURPOSE: Changes in aortic geometry or presence of aortic valve (AoV) disease can result in substantially altered aortic hemodynamics. Dilatation of the ascending aorta or AoV abnormalities can result in an increase in helical flow. METHODS: 4D flow magnetic resonance imaging was used to test the feasibility of quantitative helicity analysis using equidistantly distributed 2D planes along the entire aorta. The evaluation of the method included three parts: (1) the quantification of helicity in 12 healthy subjects, (2) an evaluation of observer variability and test-retest reliability, and (3) the quantification of helical flow in 16 patients with congenitally altered bicuspid AoVs. RESULTS: Helicity quantification in healthy subjects revealed consistent directions of flow rotation along the entire aorta with high clockwise helicity in the aortic arch and an opposite rotation sense in the ascending and descending aorta. The results demonstrated good scan-rescan and inter- and intraobserver agreement of the helicity parameters. Helicity quantification in patients revealed a significant increase in absolute peak relative helicity during systole and a considerably greater heterogeneous distribution of mean helicity in the aorta. CONCLUSION: The method has the potential to serve as a reference distribution for comparisons of helical flow between healthy subjects and patients or between different patient groups.

Takotsubo cardiomyopathy presenting as postoperative atrial fibrillation.

Takotsubo cardiomyopathy (TC) is a condition which was first acknowledged in Japan and is characterized by a reversible systolic dysfunction of the apical or mid segments of the left ventricle. Typically affecting women in the post-menopausal population, it is triggered by intense emotional, physical or medical stress. Also known as apical ballooning syndrome or stress cardiomyopathy, TC derives its name from the left ventricular angiographic appearance of a 'Takotsubo', literally translated as an 'octopus fishing trap' in Japanese. Patients often describe chest pain, have ischemic electrocardiogram (ECG) changes and positive cardiac enzymes mimicking an acute coronary syndrome. Obstructive coronary artery disease is excluded with prompt cardiac catheterization. We present the case of a 78-year-old lady, post gynecological surgery, presenting with palpitations and ECG confirming fast atrial fibrillation. Despite spontaneous cardioversion, she went on to develop ECG changes and cardiac enzyme elevations suggestive of an acute myocardial infarction. Cardiac catheterization was performed and confirmed the diagnosis of TC. It highlights an atypical presentation of TC, which can present initially as an arrhythmia in the postoperative phase as a consequence of the supraphysiological effects of elevated circulating plasma catecholamines. It reiterates the importance of prompt diagnosis and treatment to prevent cardiac decompensation in a condition poorly understood.

Activation of epileptiform activity by mental arithmetic.

Activation of epileptic seizures or electroencephalographic epileptiform discharges by mental calculation is rare. We report the case of a 34-year-old right-handed accountant with a 20-year history of generalized tonoclonic seizures. Although clinical seizures were unrelated to performance of mental arithmetic, epileptiform activity appeared when she attempted difficult mental arithmetic. Apart from one occasion, epileptiform discharges did not impair her ability to provide accurate answers to mathematical problems.

Antirheumatic drug concentrations in human synovial fluid and synovial tissue. Observations on extravascular pharmacokinetics.

Antirheumatic drug concentrations have been measured in human synovial fluid and synovial tissue, and provide insights on: (1) extravascular pharmacokinetics; (2) articular pathophysiology; and (3) the factors which modify drug levels in inflamed tissues. Concentrations of free drug in synovial fluid and plasma are the same in all conditions except rheumatoid and infectious arthritis, where the most severely afflicted joints may contain lower synovial fluid drug concentrations. This finding may be relevant to the chronicity and intractability of chronic arthritis. After single-dose therapy and a characteristic 'equilibration time', higher concentrations are found in synovial fluid than in plasma - a phenomenon which results from relative drug sequestration across the trans-synovial diffusion barrier away from the organs of elimination. Studies of oral, parenteral, topical and intra-articular antirheumatic drug therapy are reviewed, and recommendations are made for the conduct of future studies.

Biologic agents and immunotherapy in rheumatoid arthritis. Progress and perspective.

Advances in our understanding of rheumatoid synovitis have been coupled with increasingly refined methods from biotechnology to produce promising therapeutic agents. Monoclonal antibodies (MoAbs), recombinant cytokines, cytokine receptor fusion proteins and other biologics have been elevated from the status of novel reagents applied in phase I toxicity trials to, in some cases, substantially evaluated and validated tools awaiting federal regulatory approval. Biologic agents will soon be released for the treatment of patients with RA. We review some of the most promising preclinical work that supports a position of optimism regarding the future of RA. We also speculate on the potential role for biologics in future management of patients with RA.

The effect of amantadine on levodopa-induced dyskinesias in Parkinson's disease: a double-blind, placebo-controlled study.

We performed a double-blind, placebo-controlled, crossover study to assess the effect of amantadine versus placebo on levodopa-induced dyskinesias in Parkinson's disease. We found a 24% reduction in the total dyskinesia score after amantadine administration (p = 0.004). This improvement was achieved without any influence on the severity of "on" period parkinsonism. The results confirm that amantadine reduces levodopa dyskinesias and support the hypothesis that dyskinesias can be reduced by blockade of excitatory pathways in the basal ganglia.

Hydraulic resistance in bones of the canine shoulder.

The hydraulic properties of trabecular bone were explored in both sides of normal canine shoulders by following the hydrostatic pressure response to transchondral injections of saline. In a series of isovolumetric injections at sites 9 mm beneath either joint surface, the pressure consistently rose higher and lasted longer in the humerus than it did in the scapula. Hydraulic resistance, the linear function of pressure per unit flow, averaged 8.8 times higher within the humerus than in the scapula in a second series of experiments. Hydraulic resistance fell by average factors of 9.6 in the humerus and 4.3 in the scapula when the surrounding bone was cut away to leave the injection site centered within a 1 cm 'cube' of trabecular bone. Direct determinations of hydraulic resistance provide a useful tool for the study of normal and abnormal physiology in trabecular bone.

The action of isoprenaline on the electrophysiological properties of hypertrophied left ventricular myocytes.

The electrophysiological effects of the beta-agonist, isoprenaline, on hypertrophied left ventricular myocardium were measured to understand better the arrhythmic effects of beta-stimulation on the hypertrophied heart. Left ventricular hypertrophy was induced in guinea-pigs by constriction of the thoracic aorta. An age-matched sham-operated group served as controls. Isolated myocytes were held under voltage- and current clamp and the effect of isoprenaline on the L-type Ca2+ current, I(Ca), a Cl- current, I(Cl), and action potential morphology were measured. Cardiac growth was mirrored by cellular hypertrophy. I(Ca) and I(Cl) current density were reduced as myocyte hypertrophy progressed. The augmentation of I(Ca) and I(Cl) by isoprenaline was also reduced in hypertrophy, but no other characteristics of the two currents, or the dose-dependency of the action of isoprenaline were a function of cardiac growth. Isoprenaline prolonged the action potential, but to a smaller extent in hypertrophied myocytes. This difference in action potential prolongation was abolished by glibenclamide. The changes to I(Ca) and I(Cl) in hypertrophy would not tend to increase triggered activity in this situation. Under maximum inotropic stimulation hypertrophied myocytes show action potential changes which are consistent with intracellular ATP depletion, and which could enhance the likelihood of re-entrant circuits. A simple diffusion model for oxygen is constructed to demonstrate the possibility of cellular hypoxia in hypertrophied myocytes.

Vertebral artery occlusion following manipulation of the neck.

A 23-year-old woman developed brainstem infarction following cervical manipulation. Vertebral angiography showed total occlusion of the left vertebral artery with a thrombus extending into the basilar artery. The literature dealing with this rare but serious complication of cervical manipulation is reviewed.

Sodium valproate (Epilim) in epilepsy: a trial.

Of thirty-five patients with various types of epilepsy treated with sodium valproate, 15 achieved complete seizure control on that drug alone, 12 other patients benefited and eight failed to improve on the drug. Excellent results were more likely in those with petit mal epilepsy and in those whose epilepsy was controlled with other drugs at the expense of side effects. Three patients were unable to tolerate valproate, but in general few patients experienced side effects and several patients felt much better on valproate than on their previous drugs. A twice daily dosage regime was satisfactory. Plasma valproate levels at the final dose covered a wide range, 0.21 - 1.2mmol/l (34 to 190 microgram/ml) and did not correlate with response, lack of response or side effects.

Neurotrauma in infants. Shaken impact syndrome (inflicted head injury).

In summary, inflicted cerebral trauma is a devastating but ultimately preventable brain injury caused by unique physiologic mechanisms that result in a distinctive pattern of injury. Nurses in a variety of settings, from the clinic and emergency room to the pediatric intensive care unit, play a major role in the identification, documentation, diagnosis, treatment, and prevention of ICT. The nurse's unique training also promotes prevention education and nonjudgmental support of the family.