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Our aim was to investigate if seemingly identical head and neck trauma would generate differing types of brain damage. We experimentally evaluated induced brain injuries immediately after trauma exposure, and at 1 week post-injury. Anesthetized rabbits were exposed once to a sagittal rotational acceleration head and neck injury at either a high or a low load level, using either flexion or extension. A high-load extension trauma induced scattered meningeal petechial hemorrhages and no deaths, in contrast to a flexion trauma of the same level, which resulted in extensive parenchymal and meningeal hemorrhages, and all animals succumbed immediately. A low-level flexion trauma induced scattered meningeal petechiae, but no gross damage, while extension at the same force generated no macroscopically visible acute brain injury. Immunohistochemical investigations carried out at 7 days disclosed that a low-level flexion trauma, as well as both low- and high-level extension exposures, all induced diffuse brain injuries in the cerebral cortex and white matter, corpus callosum, hippocampus, brainstem, and cerebellum, as revealed by abnormal distribution of neurofilaments, a prevalence of β-amyloid precursor protein, and astrogliosis. The diffuse brain injury seen after a low-level flexion trauma was equal to or more extensive than that seen after a high-level extension trauma. A low-level extension trauma induced only minor histopathological abnormalities. We conclude that a sagittal rotational acceleration trauma of the head and neck induced diffuse brain injury, and that flexion caused more extensive damage than extension at the same applied load.

Intake of specially processed cereal (SPC) stimulates endogenous antisecretory factor (AF) activity, and SPC intake has proven to be beneficial for a number of clinical conditions. The aim of the present study was to investigate the dosage relationship between SPC intake and plasma AF activity and to further correlate achieved AF levels to a biological effect. SPC was fed to rats in concentrations of 5, 10 or 15 % for 2 weeks. A further group was fed 5 % SPC for 4 weeks. AF activity and the complement factors C3c and factor H were analysed in plasma after the feeding period. Groups of rats fed the various SPC concentrations were subjected to a standardised freezing brain injury, known to induce increases in intracranial pressure (ICP). The AF activity in plasma increased after intake of SPC, in a dosage-and time-dependent manner. The complement factors C3c and factor H increased in a time-dependent manner. Measurements of ICP in animals fed with SPC prior to the brain injury showed that the ICP was significantly lower, compared with that of injured rats fed with a standard feed, and that the change was dose and time dependent. AF activity increases, in a dosage-and time-dependent manner, after intake of SPC. The inverse relationship between ICP after a head injury and the percentage of SPC in the feed indicate that the protective effect is, to a large extent, due to AF.Key words: Antisecretory factor activation: Complement factors: Intracranial pressure: ELISA: Inflammation Antisecretory factor (AF), also named S5a, is a 43 kDa ubiquitously expressed protein originally identified through its capacity to inhibit intestinal hypersecretion (1) . Further studies have shown that AF is also a potent anti-inflammatory agent (2 -6) . In the plasma of healthy individuals, the major part of AF is present in an inactive form (7) . AF is activated through intestinal exposure to bacterial toxins or through the intake of specific food components, e.g. in the form of specially processed cereals (SPC) (7 -9) . Clinical studies have shown that a diet-induced increase in AF activity is beneficial for a number of diseases in which inflammation and/or secretory disturbances are parts of the pathophysiology (6,8,9) .The mechanisms through which SPC activate AF are currently unknown, although exposure of the intestinal mucosa to SPC, in certain aspects, may be assumed to mimic that of intestinal exposure to bacterial toxins, i.e. by inducing an inflammatory response. Such a response could be a first step in the activation process. In a previous study, proteomics was used to study the differences in protein expression in the livers of rats fed an SPC feed and rats fed a standard feed (10) . A selective increase in the expression of glutathione-S-transferase m in the livers of rats fed the SPC feed was observed. Glutathione-S-transferase m does not appear to be involved in AF activation, and the increased expression is probably an unrelated effect of the SPC feed.In a recent study, in which rats were exposed to blast injury t...