Heparin-coated circuits reduce activation of granulocytes during cardiopulmonary bypass. A clinical study.

Activated granulocytes release highly active enzymes such as myeloperoxidase and lactoferrin, which can be involved in tissue destruction mediated by oxygen free radicals. Cardiopulmonary bypass has been reported to activate granulocytes. Bypass circuits coated with heparin have been shown to reduce release of granulocyte factors in experimental studies. In the present study, heparin-coated circuits were compared with noncoated circuits. In seven patients undergoing coronary bypass, heparin-coated circuits were used (group HC), and seven served as control patients (group C). In group HC the heparin dose was reduced to 75% (225 IU/kg). Group C had the standard dose of 300 IU/kg. No preoperative differences in myeloperoxidase and lactoferrin were observed between the groups. At the end of bypass in both groups, there was a significant increase of these enzymes (p less than 0.001) followed by a later decrease. In group HC, however, the release of myeloperoxidase was significantly lower than in group C (215 +/- 24 versus 573 +/- 133 micrograms/L, mean +/- standard error of the mean). The release of lactoferrin was significantly lower in group HC than in group C both at the end of cardiopulmonary bypass (659 +/- 79 versus 1448 +/- 121 micrograms/L) and 3 hours after bypass (224 +/- 37 versus 536 +/- 82 micrograms/L). Granulocytes as well as total number of leukocytes continued to increase until 1 hour after bypass (p less than 0.001) and then manifested a slow decrease. It was concluded that the use of heparin-coated circuits reduced the release of granulocyte factors because of lower activation of leukocytes.     

Subtraction radiography of interradicular bone lesions.

Subtraction and conventional radiography were evaluated for their diagnostic potential to assess interradicular bone lesions in the mandibular premolar region. Both conventional radiographs and subtraction images were interpreted by 10 observers. The receiver-operating characteristic (ROC) technique was used to compare the two techniques. The diagnostic validity was higher for the subtraction technique, both for lesions confined to cancellous bone and for lesions including the cortical bone, than for the conventional technique. For bone defects confined to cancellous bone the diagnostic accuracy was lower than those reported from periapical bone lesions irrespective of whether subtraction or conventional radiography was used. We conclude that subtraction radiography improves the detectability of bone lesions, shallow ones in particular. Lesions in the interradicular bone are more difficult to detect than those in the periapical bone.     

Spatial learning impairments in rats with selective immunolesion of the forebrain cholinergic system.

A monoclonal antibody to the low-affinity NGF receptor, 192 IgG, coupled to a cytotoxin, saporin, was recently introduced as an efficient selective neurotoxin for the NGFr-bearing cholinergic neurones in the rat basal forebrain. In the present study we report that an intracerebroventricular injection of this 192 IgG-saporin conjugate induces a severe, long-lasting spatial learning impairment, as assessed in the Morris water-maze task. This behavioural impairment was associated with 65-90% depletion of choline acetyltransferase activity (ChAT) in the hippocampus and cortex. ChAT activity associated with other cholinergic neurone systems in the brain (striatum, mesencephalon, spinal cord), was left virtually unaffected. This new immunotoxin holds great promise as a tool for selective and efficient lesions of the forebrain cholinergic system in functional and behavioural studies.     

Adhesion of human platelets to albumin is synergistically increased by lysophosphatidic acid and adrenaline in a donor-dependent fashion.

Lysophosphatidic acid (LPA) and adrenaline are weak platelet activators considered important for thrombus formation, and were previously shown to synergistically increase platelet aggregation. Here we investigate synergistic activation by LPA and adrenaline when measuring platelet adhesion. Platelet-rich plasma from healthy blood donors together with adrenaline and/or LPA were added to protein-coated microplates. Platelets were allowed to adhere and the amount of adhesion detected enzymatically. The LPA and adrenaline combination induced a synergistic increase of platelet adhesion to a normally non-adhesive albumin surface. The degree of synergy varied markedly between individuals; these variations could not be explained by age, gender, blood type or different amounts of platelets, oxidized low-density lipoprotein, insulin or glucose in plasma. There was a trend indicating increased synergistic effect for platelets sensitive to adrenaline stimulation. The synergistic effect was blocked by the alpha2-adrenoceptor antagonist yohimbine and inhibited by the ADP scavenger system creatine phosphate/creatine phosphokinase and antibodies against alphaIIbbeta3. Furthermore, platelets adhering to albumin after adrenaline and LPA treatment expressed P-selectin. In conclusion, LPA and adrenaline act synergistically to increase alphaIIbbeta3-mediated platelet adhesion to albumin, dependent on alpha2-adrenoceptor signalling and platelet secretion. We also confirm that synergistic platelet activation achieved with LPA and adrenaline is highly donor dependent.     

Relevance of stimulus duration for activation of motor and sensory fibers: implications for the study of H-reflexes and magnetic stimulation.

Electric stimuli with durations of 0.5-1.0 msec are optimal for studies of H-reflexes. It is more difficult to obtain H-reflexes with shorter duration stimuli or with magnetic stimulation. In order to understand this behavior, we studied the excitation thresholds for motor and sensory fibers in the ulnar, median and tibial nerves using both electric and magnetic stimulation. For short duration electrical stimuli (0.1 msec) the threshold for motor fibers is lower than for sensory fibers. For longer duration electric stimuli (1.0 msec) the threshold for sensory fibers is lower. For magnetic stimulation the threshold for motor fibers is much lower than for sensory fibers. Thus, stimulus duration is a critical parameter for sensory fiber excitation, and current magnetic stimulators are not optimal.     

A computer and video display based system for training eccentric viewing in macular degeneration with an absolute central scotoma

A new approach designed to establish the most suitable area for eccentric viewing and to teach and train patients with severe age-related macular degeneration (AMD) to use the eccentric viewing technique is described. Using a computer and video display based system, as well as software written specifically for this purpose, we investigated and trained ten consecutive patients with AMD. The patients were 80.1 ± 5.6 years old, on average. All of them had an absolute central scotoma. Mean visual acuity was 0.035 ± 0.016. After 30 min of testing, instruction and reading on the screen, followed by 2.6 ± 0.69 one-hour training sessions, on average, with the low vision therapist, reading newspaper and book texts with the aid of hyperoculars or aplanatic systems and a very short reading distance, the patients achieved a reading speed of 58.9 ± 19.7 words/min, significantly (p<0.001) higher than the initial speed when reading on the screen, 11.5 ± 4.5 words/min.     

Longitudinal analysis of the relation between moderate long‐term stress and health

The main goal of the present work was to longitudinally examine consequences of long‐term moderately elevated levels of stress for various health outcomes. To address this issue, data covering 10 years was used from the ongoing Swedish population‐based prospective Betula Study. Based on the ratings on a validated self‐reported stress scale, matched subsamples between 40 and 65 years of age were divided into a high (n = 137) and low (n = 211) stress group. The reported incidence of cardiovascular, diabetes, psychiatric, tumour and musculoskeletal diseases was assessed 5 and 10 years after baseline (baseline = 1993–1995) without contaminating effects of past health history. The incidence of diseases 5 years after baseline assessment showed no differences between the groups. After 10 years, there was a significantly higher incidence of psychiatric diseases, mainly depression in the high‐stress group as well as a significant effect for tumours, although the number of cases was low. Although moderately elevated stress level may have a possible impact on psychiatric diseases especially depression and some tumours, it seems that prolonged moderate stress does not appear to be harmful to other stress‐related diseases. Copyright © 2007 John Wiley & Sons, Ltd.     

Methylprednisolone treatment in acute spinal cord injury: the myth challenged through a structured analysis of published literature.

BACKGROUND CONTEXT: Methylprednisolone has evolved during the 1990s, through the results obtained from the National Acute Spinal Cord Injury Studies NASCIS II and III, as a standard treatment in acute spinal injury. PURPOSE: To evaluate the scientific basic for the use of methylprednisolone in acute spinal cord injury. STUDY DESIGN: Systematic review of the accumulated literature. METHODS: Critical evaluation of the data obtained in the NASCIS II and III studies plus other accumulated literature. RESULTS: Analyses have been made on subgroups of the study populations, and the results were based on statistical artefacts. Furthermore, improved functional recovery shown by these studies was not clinically significant. CONCLUSION: There is insufficient evidence to support the use of methylprednisolone as a standard treatment in acute spinal cord injury.