Use of computer based testing of youth hockey players with concussions

Concussion is a potentially serious injury for athletes. Recent statistics suggest that approximately 300,000 sports-related traumatic brain injuries occur annually in the United States. Soccer, rugby, football, and ice hockey are all considered high-risk team sports for concussion. Hockey-related concussions are of particular concern in Canada, where over 500,000 players compete annually in ice hockey. The United States is now registering similar numbers of players. Return to play issues are one of the most difficult issues for physicians caring for concussed athletes. The advent of computerized neuropsychological testing adds another tool to assist in this process. It also appears to enhance the education process for players, coaches, and parents on the potential seriousness of concussion for these young athletes.     

Distinct types of microglial activation in white and grey matter of rat lumbosacral cord after mid-thoracic spinal transection

The inflammatory response has been characterized in the lumbosacral segments (L4-S1) of rats after spinal transection at T8. Immune cells were identified immunohistochemically using antibodies to complement type 3 receptor, CD11b (OX-42), the macrophage lysosomal antigen, CD68 (ED1), major histocompatibility complex class II (MHC II), and CD163 (ED2), a marker of perivascular cells. One week after cord transection, OX-42+ microglial density had nearly doubled. In the white matter, microglia became enlarged, often with retracted processes. In contrast, microglia in the grey matter remained ramified although nearly half of those lying medially contained clusters of ED1+ granules. After 8 weeks, ED1+ (+/-MHC II) macrophages were prominent in regions of Wallerian degeneration extending from dorsolateral to ventral funiculi. Microglial density remained raised in grey matter, particularly in the ventral horns of L4/5. Ramified microglia expressing MHC II+ (+/-ED1) extended from deep in the dorsal columns and around the central canal to the ventral columns. More ED2+ (+/-MHC II) perivascular and meningeal cells were recruited and expressed ED1. Thus, distinct from their conversion into macrophages in the white matter, the activation of ramified microglia after degeneration in the grey matter involves expression of ED1 without morphologic transformation.     

The effect of stem stiffness on femoral bone resorption after canine porous-coated total hip arthroplasty

Bilateral noncemented total hip arthroplasty (THA) was produced in dogs to determine the effect of stem stiffness on stress-related bone resorption. Two porous-coated femoral implants of substantially different stiffnesses were designed for direct comparison. One was manufactured from cobalt-chromium (CoCr) alloy, the other from titanium alloy. The titanium stem was hollowed out to a wall thickness of 1 mm to further reduce its stiffness. The cumulative stiffness differences were about 5.4-fold axially and 3.6-fold in bending and torsion. Staged bilateral THA was performed on eight dogs. Each dog received a stiff CoCr stem on one side and a flexible titanium stem on the other. After death, the femora were removed and processed for undecalcified thin-section histology. Bone ingrowth and remodeling were quantified by computer-aided image analysis and compared between stem designs. All femoral specimens showed bone ingrowth fixation of both stiff and flexible stems along the implant length. Tetracycline labeling indicated active bone turnover in the femoral cortex and in regions of ingrowth. However, gross differences in femoral bone remodeling were observed both roentgenographically and histologically. Femora with the flexible stems consistently showed much less bone resorption than those with the stiff stems. Quantitative analysis of paired cross-sections indicated an average of 25%-35% more cortical bone area in the femora with flexible stems. Severe resorption of the cortex in the midstem region occurred in three of the femora with the stiff stems but in none with the flexible stems. Stem stiffness strongly influences bone remodeling. The flexible stem results in more uniform load transfer and less stress shielding.     

Relationship between numbers of beta adrenergic receptors in lymphocytes and disease severity in asthma

In order to assess the status of beta adrenergic receptors in bronchial asthma, binding studies using (−) [³H] dihydroalprenolol (DHA) were performed on lymphocytes of 10 control subjects and 11 stable asthmatic patients. Specific DHA binding was generally lower at all DHA concentrations in asthmatics. At 12 nM DHA concentration, specific DHA binding was 391 ± 40 fM/mg protein in controls and 263 ± 35 fM/mg protein for asthmatic subjects (p < 0.05). A highly statistically significant positive correlation between specific DHA binding (at 12 nM DHA) and FEV₁/FVC% was observed (r = 0.93, p < 0.01), with those asthmatic subjects with the more severe airway obstruction and disease severity showing lower DHA binding. The results of the study suggest that a lymphocyte beta adrenergic receptor defect may be present among some patients with asthma. The magnitude of the receptor abnormality appears to be related to disease severity and degree of airway obstruction as measured by FEV₁/FVC%. Documentation of drug consumption was made, and restriction of beta adrenergic agonists was attempted; theophylline and corticosteroids were the predominant drugs used in the study. Even with these precautions, it is possible that the differences in DHA binding observed among subjects are the results of greater drug (e.g., theophylline and corticosteroids) consumption by the clinically more severe patients. On the other hand, the lymphocyte receptor alteration noted may reflect a more general beta adrenergic receptor abnormality in bronchial asthma.     

Alleviation of constipation in the elderly by dietary fiber supplementation

To alleviate the constipation problem among the elderly residents of Essex County Geriatric Center, New Jersey, a fiber-supplemented dietary regimen was started. Under this regimen, bran was added to the hot breakfast cereal, thus increasing the crude fiber content of the diet to 6-8 gm compared with the former 4-6 gm. As estimated from recent analysis data, the total dietary fiber was increased from 25 to 40 percent by the addition of bran. This amount of fiber proved effective in preventing constipation in 60 percent of the residents even though many of them had previously required laxatives. Additional programs of dietary fiber supplementation were devised for residents who did not respond to the cereal supplementation or who required nasogastric feedings. In the year following initiation of the program at this Center, the use of laxatives was virtually eliminated, and the institution's pharmacy reported a saving of $44,000 in expenditures for laxative drugs. Recipes are included for the bran-supplemented hot cereal, a special fiber-prune juice supplement, and a fiber-rich liquid for tube-feedings.     

Corneal thickness and endothelial cell density measured by non-contact specular microscopy and pachymetry in Rhesus macaques (Macaca mulatta) with laser-induced ocular hypertension

PURPOSE: Sustained increase in intraocular pressure (IOP) in humans results in a loss of corneal endothelial cells and an increase of corneal thickness. The effects of chronically elevated IOP on the corneal endothelium of monkeys with laser-induced ocular hypertension, a commonly used animal model of human glaucoma have not been documented. This study examined the central corneal thickness (CCT), the corneal endothelial cell density (ECD), and the corneal endothelial cell size (ACS) in Rhesus monkeys with experimental ocular hypertension.Materials and methods. Ten male monkeys with argon laser-induced ocular hypertension in one eye for an average duration of 2.4+/-0.7 years, were sedated with ketamine hydrochloride, and the CCT, ECD, and ACS measured at the center of the cornea of both eyes with a Topcon SP-2000P non-contact specular microscope (Topcon America Corporation((R)), Paramus, NJ, USA). CCT was also measured using a DHG-500 Pachette ultrasonic pachymeter (DHG Technology Inc., Exton, PA, USA). Mean and standard deviation (S.D.) of CCT, ECD and ACS for each eye was calculated and statistically compared.Results. Mean CCT in the hypertensive and normal eyes measured by specular microscopy was 0.477+/-0.023mm and 0.468+/-0.020 mm, respectively. Mean ECD in the hypertensive and normal eyes was 2601.7+/-631.8 and 3990.2+/-402.9 cells mm(-2), respectively. The mean size of the endothelial cells was 252.4+/-23.9 micro m(2) in the normal eye and 408.7+/-115.0 microm m(2) in the hypertensive eye. No significant difference in the measurement of CCT was observed between the specular microscope and the pachymeter (p=0.46).No significant difference in the mean CCT was observed between the two eyes (p=0.4820), whereas the mean ECD was significantly lower in the hypertensive eye than in the normal eye (p<0.001). The ECD was inversely related to the length of IOP elevation (p<0.001). CONCLUSIONS: No difference in the corneal thickness measurement was observed between the specular microscopy and the pachymetry techniques. Chronic ocular hypertension did not significantly affect the CCT, but caused a significant loss of endothelial cells in the center of the cornea of the laser treated eyes compared to the normotensive eyes. The duration of elevated IOP was the most important factor affecting the ECD.     

Relationship between stimulated inositol lipid hydrolysis and contractility in guinea-pig visceral longitudinal smooth muscle

Carbamylcholine caused a marked, concentration-dependent stimulation of [3H]Ins P, [3H] InsP2 and to a lesser extent [3H]InsP3 production in guinea-pig longitudinal smooth muscle prelabelled with myo-[3H]inositol. Accumulation of these three inositol phosphates showed differential sensitivity to LiCl. Muscle contraction was apparent at lower concentrations of carbamylcholine. Both responses were mediated via muscarinic-type receptors. An association of inositol phosphate production and contractility was also observed in response to substance P, histamine and noradrenaline, the latter via an alpha-adrenergic mechanism. The Ca2+-channel agonist CGP 28392 failed to stimulate inositol phosphate production despite inducing a contractile response. Carbamylcholine -induced inositol phosphate production persisted in the presence of D600 or Mn2+ despite loss of contractile activity. However, both responses showed a similar, marked dependence on the presence of Ca2+ in the extracellular medium. Mn2+ could restore basal and stimulated inositol phosphate production in low Ca2+ solutions but could not substitute for Ca2+ in restoring contractility. The results suggest that stimulated inositol lipid hydrolysis in longitudinal smooth muscle does not result from Ca2+ entry into the tissue, although the response does depend on the concentration of divalent cations in the extracellular medium. This dependency may be related to the maintenance of membrane potential and possibly phospholipid conformation.     

Thoracoabdominal aortic aneurysms: preoperative and intraoperative factors determining immediate and long-term results of operations in 605 patients

Graft inclusion and vessel reattachment to openings made in the graft were employed in the treatment of 605 patients with thoracoabdominal aortic aneurysms. These patients were divided into four groups on the basis of the extent of aneurysm. Group I consisted of those patients with involvement of most of the descending thoracic and upper abdominal aorta; group II involved most of the descending thoracic aorta and most or all of the abdominal aorta; group III involved the distal descending thoracic aorta and varying segments of abdominal aorta; and group IV involved most or all of the abdominal aorta including the segment from which the visceral vessels arose. The cause of aneurysm formation was medial degenerative disease in 80%, and dissection in 17%; other causes were responsible in the remaining 3%. The median age was 65 years and associated diseases including aneurysms involving other segments, atherosclerotic occlusive disease, heart disease, chronic obstructive pulmonary disease (COPD), hypertension, and renal insufficiency were frequent. The aneurysm was symptomatic in 70% of cases and rupture had occurred in 4% of cases. There were 54 (8.9%) early (30-day) deaths and 151 late deaths; 400 (66%) patients were still alive 3 months to 20 years after operation, including 60% at 5 years. Statistically significant pre- and intraoperative variables by univariate analysis that were predictive of increased risk of early death were advancing age, associated diseases that included COPD, renal artery occlusive disease, atherosclerotic heart disease, renal insufficiency, and long aortic clamp time. Three of these (age, clamp time, and the presence of COPD) retained significance by multivariate analysis. Variables predictive of risk of late death were age, dissection, extent of aneurysm, rupture, heart disease, cerebrovascular disease, COPD, hypertension, and poor renal function. Age, rupture, renal dysfunction, extent of aneurysm, and dissection retained their significance by multivariate analysis. Variables predictive of neurologic disturbances of the lower extremities included rupture, reattachment of intercostal and lumbar arteries, clamp time, dissection, extent and age. Rupture, reattachment of vessels, dissection, and extent of aneurysm retained significance by multivariate analysis. Thus, the risk of this complication was greatest in patients with extensive lesions (group II) with aortic dissection. The greatest risk of renal failure after operation that required dialysis was in patients who had impaired renal function before operation. Methods employed did not prevent these complications.     

The use of an oral prostaglandin inhibitor following splintage in fractures of the distal radius--a prospective trial

A prospective, double-blind, controlled trial is reported in which oral diclofenac, a prostaglandin inhibitor, was given for 1 week immediately following the removal of splintage for fracture of the distal end of the radius. The patients who received the prostaglandin inhibitor had less pain, a more rapid recovery of range of movement and a stronger grip than those who received a placebo.