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Advanced magnetic resonance imaging (MRI) methods were shown to be able to detect the subtle structural consequences of mild traumatic brain injury (mTBI). The objective of this study was to investigate the acute structural alterations and recovery after mTBI, using diffusion tensor imaging (DTI) to reveal axonal pathology, volumetric analysis, and susceptibility weighted imaging (SWI) to detect microhemorrhage. Fourteen patients with mTBI who had computed tomography with negative results underwent MRI within 3 days and 1 month after injury. High resolution T1-weighted imaging, DTI, and SWI, were performed at both time points. A control group of 14 matched volunteers were also examined following the same imaging protocol and time interval. Tract-Based Spatial Statistics (TBSS) were performed on DTI data to reveal group differences. T1-weighted images were fed into Freesurfer volumetric analysis. TBSS showed fractional anisotropy (FA) to be significantly (corrected p

Pituitary adenylate cyclase activating polypeptide (PACAP) is a bioactive peptide with diverse effects in the nervous system. In addition to its more classic role as a neuromodulator, PACAP functions as a neurotrophic factor. Several neurotrophic factors have been shown to play an important role in the endogenous response following both cerebral ischemia and traumatic brain injury and to be effective when given exogenously. A number of studies have shown the neuroprotective effect of PACAP in different models of ischemia, neurodegenerative diseases and retinal degeneration. The aim of this review is to summarize the findings on the neuroprotective potential of PACAP in models of different traumatic nerve injuries. Expression of endogenous PACAP and its specific PAC1 receptor is elevated in different parts of the central and peripheral nervous system after traumatic injuries. Some experiments demonstrate the protective effect of exogenous PACAP treatment in different traumatic brain injury models, in facial nerve and optic nerve trauma. The upregulation of endogenous PACAP and its receptors and the protective effect of exogenous PACAP after different central and peripheral nerve injuries show the important function of PACAP in neuronal regeneration indicating that PACAP may also be a promising therapeutic agent in injuries of the nervous system.

We examined the neuro/axono-protective potential of a novel poly (ADP-ribose) polymerase (PARP) inhibitor L-2286 in a rat impact acceleration brain injury model. Male Wistar rats (n = 70) weighing 300-350 grams were used to determine the most effective intracerebroventricular (i.c.v.) dose of L-2286 administered 30 min after injury, and to test the neuroprotective effect at two time points (immediately, and 30 min after injury). The neuroprotective effect of L-2286 was tested using immunohistochemical (amyloid precursor protein and mid-sized mouse anti-neurofilament clone RMO-14.9 antibody) and behavioral tests (beam-balance, open-field and elevated plus maze). At both time-points, a 100 microg/rat dose of i.c.v. L-2286 significantly (p < 0.05) reduced the density of damaged axons in the corticospinal tract and medial longitudinal fascicle compared to controls. In the behavioral tests, treatment 30 min post-injury improved motor function, while the level of anxiety was reduced in both treatment protocols.

Calcium-induced, calpain-mediated proteolysis (CMSP) has recently been implicated to the pathogenesis of diffuse (traumatic) axonal injury (TAI). Some studies suggested that subaxolemmal CMSP may contribute to axolemmal permeability (AP) alterations observed in TAI. Seeking direct evidence for this premise we investigated whether subaxolemmal CMSP may contribute to axolemmal permeability alterations (APA) and pre-injury calpain-inhibition could reduce AP in a rat model of TAI. Horseradish peroxidase (HRP, a tracer that accumulates in axons with APA) was administered one hour prior to injury into the lateral ventricle; 30 min preinjury a single tail vein bolus injection of 30 mg/kg MDL-28170 (a calpain inhibitor) or its vehicle was applied in Wistar rats exposed to impact acceleration brain injury. Histological detection of traumatically injured axonal segments accumulating HRP and statistical analysis revealed that pre-injury administration of the calpain inhibitor MDL-28170 significantly reduced the average length of HRP-labeled axonal segments. The axono-protective effect of pre-injury calpain inhibition recently demonstrated with classical immunohistochemical markers of TAI was further corroborated in this experiment; significant reduction of the length of labeled axons in the drug-treated rats implicate CMSP in the progression of altered AP in TAI.

Although it is well known that traumatic brain injury (TBI) evokes traumatic axonal injury (TAI) within the brain, TBI-induced axonal damage in the spinal cord (SC) has been less extensively investigated. Detection of such axonal injury in the spinal cord would further the complexity of TBI while also challenging some functional neurobehavioral endpoints frequently used to assess recovery in various models of TBI. To assess TAI in the spinal cord associated with TBI, we analyzed the craniocervical junction (CCJ), cervico-thoracic (CT), and thoraco-lumber (ThL) spinal cord in a rodent model of impact acceleration of TBI of varying severities. Rats were transcardially fixed with aldehydes at 2, 6, and 24 h post-injury (n = 36); each group included on sham-injured rodent. Semi-serial vibratome sections were reacted with antibodies targeting TAI via alteration in cytoskeletal integrity or impaired axonal transport. Consistent with previous observations in this model, the CCJ contained numerous injured axons. Immunoreactive, damaged axonal profiles were also detected as caudal, as the ThL spinal cord displayed morphological characteristics entirely consistent with those described in the brainstem and the CCJ. Quantitative analyses demonstrated that the occurrence and extent of TAI is positively associated with the impact/energy of injury and negatively with the distance from the brainstem. These observations show that TBI can evoke TAI in regions remote from the injury site, including the spinal cord itself. This finding is relevant to shaken baby syndrome as well as during the analysis of data in functional recovery in various models of TBI.

Background information. For explanation of the formation of ‘dark’ neurons, an enigmatic phenomenon in neuropathology, we hypothesized recently that all spaces between the ultrastructural elements visible in the traditional transmission electron microscope are filled with a gel structure that stores free energy in the form of non-covalent interactions, is continuous in the whole soma—dendrite domains of neurons, and is capable of whole-cell phase transition. This hypothesis was deduced from the fact that ‘dark’ neurons can be formed, even under conditions extremely unfavourable for enzyme-mediated biochemical processes, if initiated by a physical damage. In order to gain further information on this gel structure, we perfused transcardially rats for 5 min with physiological saline containing 1 mM SDS before the perfusion of a fixative for electron microscopy. Results. Dramatic compaction of visibly intact ultrastructural elements was caused in the whole soma—dendrite domains of thinly scattered neurons (‘dark’ neurons), whereas substantial cytoplasmic swelling and patchy ultrastructural disintegration occurred in numerous other neurons (‘light’ neurons). Similar morphological changes were observed in scattered astrocytes, oligodendrocytes, pericytes and endothelial cells. Conclusions. These observations: (i) support the existence of the above intracellular gel structure in neurons; (ii) allow the conclusion that this gel structure is present in the form of an ubiquitous trabecular network surrounded by a confluent system of fluid cytoplasm; (iii) draw attention to the possibility that the previous two statements also apply to other cell types of the brain tissue; and (iv) suggest that pressure-induced direct channels exist between neurons and astrocytes.

Floral activity was studied in two apple cultivars: an Erwinia-tolerant (Treedorn') and a sensitive one (`Sampion'). Since more types of protogyny occur in apples, the period of stigma activity is different. Papillae of the exposed stigma in flowers of 'Freedom' function longer (usually more than a week) than in the delayed homogamous `Sampion'. Despite of this, cv. 'Freedom' is tolerant to Erwinia amylovora (Burr.) Winslow et al., suggesting no relationship between the floral biological type (including the exposure and longevity of stigma) and the infection by E. amylovora. According to SEM micrographs, nectary stomata in `Freedom' are already open in the flower bud, where nectar secretion starts and continues until the senescence of the stigma. However, the long period of nectar secretion does not create optimal conditions for bacterial growth, since nectar production is scant in the flowers of 'Freedom'. The surface of the nectary, its nectar-retaining capacity, and the amount and concentration of nectar may influence the susceptibility of apple cultivars. It is manifested well by the smooth nectary surface with nectary stomata rising slightly above the epidermis in flowers of cv. 'Freedom', contrasting the wrinkled, striate nectary surface with slightly sunken stomata in the flowers of 'Sampion'.

The composition of floral nectar in sour cherry cultivars studied in 1997 at Újfehértó was in agreement with our previous data, the three most frequent sugar components being glucose, fructose and sucrose. Nectar secreted at night is generally more diluted than nectar produced during the day. None of the nectar samples produced at night reached the threshold value (100 mg/ml) of bee visitation. In the majority of cultivars the difference in concentration between night and day nectar is not too high, but in two cultivars, 'Korai pipacs' and ‘Újfehértói fürtös’ the difference is quite significant. Most sucrose was found in the nectar of cvs. 'Érdi jubileum' and ‘Újfehértói fürtös’, but a high amount of sucrose was measured also in the flowers of 'Korai pipacs' and 'Meteor USA'. Nectar concentration varies from opening of the flower to petal fall to a smaller or greater degree, depending on the given cultivar. From the 9 sour cherry cultivars studied ‘Újfehértói fürtös’ and Tandy 48' had the most attractive nectar for bees. There was no correlation between nectar composition and free fertilisation. On the basis of nectar composition the majority of the sour cherry cultivars studied can be classified into the sucrose-rich category; only one cultivar, 'Érdi jubileum' had a sucrose-dominant secretory product. The composition of nectar in the studied sour cherry cultivars is preferred by bees.