Age determination of subdural hematomas: survey among radiologists.

Abusive head trauma is a severe form of child abuse. One important diagnostic finding is the presence of a subdural hematoma. Age determination of subdural hematomas is important to relate radiological findings to the clinical history presented by the caregivers. In court this topic is relevant as dating subdural hematomas can lead to identification of a suspect. The aim of our study is to describe the current practice among radiologists in the Netherlands regarding the age determination of subdural hematomas in children. This is a cross-sectional study, describing the results of an online questionnaire regarding dating subdural hematomas among pediatric and neuro-radiologists in the Netherlands. The questionnaire consisted of sociodemographic questions, theoretical questions and eight pediatric cases in which the participants were asked to date subdural hematomas based on imaging findings. Fifty-one out of 172 radiologists (30 %) filled out the questionnaire. The percentage of participants that reported it was possible to date the subdural hematoma varied between 58 and 90 % for the eight different cases. In four of eight cases (50 %), the age of the subdural hematoma as known from clinical history fell within the range reported by the participants. None of the participants was "very certain" of their age determination. The results demonstrate that there is a considerable practice variation among Dutch radiologists regarding the age determination of subdural hematomas. This implicates that dating of subdural hematomas is not suitable to use in court, as no uniformity among experts exists.

Fear conditioning and shock intensity: the choice between minimizing the stress induced and reducing the number of animals used.

Many fear conditioning studies use electric shock as the aversive stimulus. The intensity of shocks varies throughout the literature. In this study, shock intensities ranging from 0 to 1.5 mA were used, and the effects on the rats assessed by both behavioural and biochemical stress parameters. Results indicated a significant difference with respect to defaecation and freezing behaviour between controls and those animals that received a shock. Significant differences in corticosterone levels were also noted between controls and those groups that received a shock. No significant differences were found between the shock groups with regards to the stress parameters measured in our fear conditioning paradigm, indicating that the two shock groups were similarly stressed. Increased significance levels were noted for freezing behaviour as well as a lower standard error of means was found in the highest shock intensity group. We therefore recommend using the higher shock intensity (1.5 mA) as the rats in the higher shock intensity group were more homogeneously fear-conditioned and therefore the results should be more reproducible and robust than in the lower shock intensity group. This would allow for fewer rats to be used in order to gain an accurate impression of the conditioning paradigm employed.

Anatomical demonstration of the suprachiasmatic nucleus-pineal pathway.

A polysynaptic pathway is proposed to transmit light information from the retina through the suprachiasmatic nucleus of the hypothalamus (SCN) to the pineal. In the present study, the powerful transneuronal tracer, pseudorabies virus (PRV), was used to provide a detailed description of this pathway. PRV injected into the pineal subsequently labeled the superior cervical ganglion, the intermediolateral column of the upper thoracic cord, the autonomic division of the paraventricular nucleus of the hypothalamus (PVN), and the SCN. Neurons in the autonomic division of the PVN were the only PRV-labeled neurons in the hypothalamus shown to receive input from the SCN as demonstrated by the presence of vasoactive intestinal polypeptide axonal contacts. This observation concurred with the presence of ventrally placed neurons in the SCN that could only be observed a day after the appearance of PVN-labeled neurons. Nevertheless the majority of the neurons were found in the dorsomedial position of the SCN, associated with the vasopressin-containing population of SCN neurons. Confocal laser scanning microscopy showed double-labeled neurons containing PRV and vasopressin or PRV and vasoactive intestinal polypeptide. Specificity of tracing was also established by prior removal of the superior cervical ganglion, resulting in a complete absence of the tracer but in the pineal. Thus, the present study provides the anatomical basis for circadian control of melatonin secretion.

Induction of organ dysfunction and up-regulation of inflammatory markers in the liver and kidneys of hypotensive brain dead rats: a model to study marginal organ donors.

BACKGROUND: Marginal donors exposed to the full array of effects induced by brain death are characterized by low success rates after transplantation. This study examined whether organs from marginal brain dead animals show any change in organ function or tissue activation making them eventually more susceptible for additional damage during preservation and transplantation. METHODS: To study this hypothesis we first focused on effects of brain death on donor organ quality by using a brain death model in the rat. After induction of brain death, Wistar rats were ventilated for 1 and 6 hr and then killed. Sham-operated rats served as controls. Organ function was studied using standard serum parameters. Tissue activation of liver and kidney was assessed by staining of immediate early gene products (IEG: FOS, JUN), and inflammatory markers; cell adhesion molecules (Intercellular adhesion molecule-1, vascular cell adhesion molecule-1), leukocyte infiltrates (CD45, T cell receptor, CD8, CD4), and MHC class II. RESULTS: During brain death progressive organ dysfunction was observed that coincided with a significant increase in activation of immediate early genes, intercellular adhesion molecule-1, vascular cell adhesion molecule-1, CD45, and MHC class II versus nonbrain dead controls. In liver tissue also the markers for T cell receptor and CD8 significantly increased. CONCLUSIONS: These findings suggest that an immune activation with increased endothelial cell activation and immediate early gene expression occurs in marginal donors after brain death induction. We suggest that brain death should not longer be regarded as a given nondeleterious condition but as a dynamic process with potential detrimental effects on donor organs that could predispose grafts for increased alloreactivity after transplantation.

Regional calcium levels in rat and mouse brain: automated fluorimetric assay and effects of centrally acting drugs.

The effects of several drugs and other treatments on the regional levels of Ca2+ in the brain of mice and rats were determined with an automated assay, based on the formation of a fluorescent calcein complex in a continuous flow system. The method is linear (between 1.5 and 5 micrograms Ca2+ ml-1), specific (no other cations present in the brain showed fluorescence) and sensitive (10-100 mg brain tissue can be analyzed). No major effects with the following drugs, given once or repeatedly to mice at high doses were found: morphine, naloxone, haloperidol, sulpiride, chlordiazepoxide, reserpine, ethanol, mercaptopropionic acid, or pentobarbital. Cold stress produced a transient increase in the regional levels of Ca2+ in the mouse brain. Lithium sulphate produced a small increase of brain Ca2+ 24 h after a high and toxic dose. Sleep deprivation for 24 h was ineffective in these experiments. Local application of kainic acid and tetrodotoxine to the rat striatum had no acute effects, but kainic acid produced a five to tenfold increase in the levels of striatal Ca2+ 2 weeks after injection. The present study does not support earlier published findings, which suggested that several behaviourally active drugs produce significant decreases of brain Ca2+. Moreover, it provides no evidence that the several therapeutic treatments that resulted in changes in body fluid Ca2+ also alter cerebral levels of Ca2+. On the other hand, the present data do suggest that damage to nervous tissue substantially influences Ca2+ metabolism.

Divergent axon collaterals of rat locus coeruleus neurons: demonstration by a fluorescent double labeling technique.

The distribution of the noradrenaline-containing neurons of the rat locus coeruleus has been investigated with retrograde labeling techniques using two different fluorescent tracers. Injections were placed in the prefrontal cortex, the striatum, the thalamus, the hippocampus, the cerebellar cortex and the lumbar spinal cord. No evidence for locus coeruleus projections to the striatum was found. Injections in the cortex, thalamus and hippocampus revealed not only ipsilateral but also contralateral labeling of cells in the locus coeruleus. Following unilateral or bilateral homo- or heterotopic injections of the two tracers several cells of the locus coeruleus were double labeled. Combined injections of the two fluorophores in any of these forebrain areas and in the spinal cord also produced double labeled cells. The majority of double labeled cells was located in an area between the ventral and the dorsal parts of the locus coeruleus. These results indicate that individual neurons of the locus coeruleus have the possibility to influence adrenergic receptors at remote areas in the central nervous system.

Region-specific alterations of calbindin-D28k immunoreactivity in the rat hippocampus following adrenalectomy and corticosterone treatment.

The aim of this study was (i) to compare the immunocytochemical distribution of the calcium-binding protein calbindin-D28k (CB) in the hippocampus of rats with the pattern of neurodegeneration following adrenalectomy (ADX) using silver impregnation, and (ii) to investigate the CB-immunoreactivity in the hippocampus following 3 weeks corticosterone treatment. 24 h following ADX no degenerative changes, nor alterations in CB-immunoreactivity were found in the hippocampus. Both 3 and 21 days following ADX neurodegeneration in the dentate gyrus could be observed which was accompanied with a loss of CB-immunoreactive (CB-ir) cells in that parts of the dentate gyrus suffering neuronal degeneration. Additionally we observed a marked loss of CB-ir in the CA1 area both 3 and 21 days following ADX. Three weeks daily corticosterone treatment (10 mg/day) induced a marked increase of CB-ir exclusively in the CA1 pyramidal cell layer. We conclude that (i) there is a close relationship between the loss of CB-immunoreactive cells in the DG and the neuronal degeneration in the dentate gyrus following ADX, and (ii) corticosterone appears to be involved in the regulation of calbindin-D28k in the CA1 pyramidal cell layer.

Cyclic AMP in the rat cerebral cortex after stimulation of the locus coeruleus: decrease by antidepressant drugs.

The study concerned the effect of repeated treatment with antidepressant drugs on the elevation of cyclic AMP levels in the rat cerebral cortex following electrical stimulation of the locus coeruleus. Some of the tricyclic and tetracyclic antidepressant drugs inhibited the cyclic AMP response. Desmethylimipramine was the most potent (effective when given 5 mg/kg/day for 2 weeks). Imipramine and nomifensine (daily dose 10 mg/kg for 2 weeks) produced slight decreases, while iprindol and clomipramine were ineffective. After 6 weeks of treatment (daily 10 mg/kg) iprindol, clomipramine and mianserin were without effect. The cyclic AMP response was suppressed by higher doses of the latter two drugs (2 weeks, 20 mg/kg/day). These results indicate that tricyclic and tetracyclic antidepressant drugs are able to decrease cerebral noradrenergic neurotransmission of locus coeruleus neurons, as far as this is mediated by cyclic AMP. It is not clear, however, whether such modification is related to the therapeutic action of antidepressant drugs.

Evidence that stress activates glial lactate formation in vivo assessed with rat hippocampus lactography.

Extracellular lactate of the rat hippocampus is inter alia increased by immobilization stress. The origin of lactate is, however, not well established, so it is not known whether it is mainly derived form neurons or glial cells. Dialysates were collected shortly (1 or 2 days) or with a delay (14 or 15 days) after implantation of the probe. In the short-term experiment lactate increased after stress, both with or without glucose added to the perfusate. In the long-term experiment there was marked gliosis around the dialysis probe and the stress effects were seen only in the presence of 5 mM glucose. The results are consistent with the idea that stress induces glycogenolysis and lactate export from astroglial cells via neurotransmitter or hormonal related processes.

Macular grid laser photocoagulation in uveitis.

AIMS/BACKGROUND: The aim of this study was to evaluate whether grid laser photocoagulation of the macula is beneficial in the treatment of cystoid macular oedema in patients with uveitis. METHODS: Six eyes of five patients with long standing cystoid macular oedema due to chronic uveitis were treated by grid laser photocoagulation of the macula. RESULTS: In the first weeks after treatment a temporary increase of oedema and paracentral scotomas were observed. At the long term follow up of more than 18 months in all patients, macular oedema had been reduced significantly or disappeared in all eyes treated. One eye had a significant increase in Snellen acuity, three eyes more or less stabilised, and two eyes deteriorated. CONCLUSION: The beneficial effect of laser treatment on visual acuity in patients with uveitis might be more favourable if performed at an earlier stage of the disease.

Analysis of IL-6 levels in human vitreous fluid obtained from uveitis patients, patients with proliferative intraocular disorders and eye bank eyes.

Several studies suggest a role for IL-6 in the pathogenesis of uveitis. Earlier we have shown that aqueous humour obtained from patients with uveitis contained raised levels of IL-6. In the study described here we investigated the IL-6 levels in vitreous fluid samples obtained from 75 uveitis patients with different uveitis entities. Vitreous samples from 14 patients with proliferative intraocular disorders (PID) and 29 eye bank eyes were used as controls. All the samples were tested in the IL-6 B9 bioassay as well as in a sensitive ELISA for IL-6. Raised IL-6 levels were detected in the vitreous fluid of uveitis patients as well as patients with PID, implicating IL-6 as a common inflammatory mediator. The highest mean level of IL-6 was found in the vitreous fluid of patients with acute retinal necrosis. The mean IL-6 levels measured by the ELISA were higher compared to the levels measured by the B9 bioassay. This may be caused by the presence of B9 bioassay inhibitory factors in the vitreous fluid of these patients.

Possible glial contribution of rat hippocampus lactate as assessed with microdialysis and stress.

Microdialysis for the continuous monitoring of lactate ("lactography") was applied in rat brain hippocampus in an attempt to establish whether lactate is of neuronal or glial origin. Lactate was analyzed with an electrochemical assay after enzymatic oxidation in dialysates derived from a short-term (1 or 2 days after implantation of the probe) and a long-term (14 or 15 days) preparation. In the short-term experiment the lactate levels in the dialysate were higher without glucose in the perfusate, whereas in the long-term experiment a several fold increase in lactate was observed in the presence of 5 mM glucose. During stress, increases in lactate were virtually similar both in the acute (with or without glucose in the perfusate) and in the chronic preparation (response in the presence of glucose only). In the long-term preparation presence of reactive astroglia cells was visualized immunohistochemically with antibodies against glial fibrillary acidic protein. Damage of the hippocampus and the corpus callosum was seen in the chronic preparation with silver impregnation staining. These results emphasize the importance of the presence of glucose in the perfusate and they are consistent with the idea that glial cells contribute to extracellular lactate in the rat hippocampus in vivo and that stress activates the astroglial glycogen pool.

Impedance recordings to determine change in extracellular volume in the brain following cardiac arrest in broiler chickens.

The present study describes a method to determine the onset and development of brain damage in broiler chickens. Exsanguination disrupts the brain metabolism and causes the brain to become ischemic. Energy-requiring systems in the cell membrane fail, which results in an ionic shift over the membrane, accompanied by a water influx into the cell. This cellular edema decreases the extracellular volume of brain tissue. In mammals, this brain damage has been measured by recording brain impedance. We adapted this approach for use with poultry. Five to six-week-old commercial broilers were equipped with impedance recording electrodes in the striatum area of the brain. Cardiac arrest was induced by means of an intravenous injection of MgCl2 and brain impedance was recorded for 30 min. The resulting curves showed a high similarity to those obtained in rats. No effects of 12 h antemortem feed deprivation on the size and rate of change in brain impedance could be found. Both in anesthetized and conscious birds, a change in brain impedance was found. We conclude that brain impedance can be used to determine the development of ischemic brain damage in broiler chickens.

Chronic but not acute foot-shock stress leads to temporary suppression of cell proliferation in rat hippocampus.

Stressful experiences, especially when prolonged and severe are associated with psychopathology and impaired neuronal plasticity. Among other effects on the brain, stress has been shown to negatively regulate hippocampal neurogenesis, and this effect is considered to be exerted via glucocorticoids. Here, we sought to determine the temporal dynamics of changes in hippocampal neurogenesis after acute and chronic exposure to foot-shock stress. Rats subjected to a foot-shock procedure showed strong activation of the hypothalamic-pituitary-adrenal (HPA) axis, even after exposure to daily stress for 3 weeks. Despite a robust release of corticosterone, acute foot-shock stress did not affect the rate of hippocampal cell proliferation. In contrast, exposure to foot-shock stress daily for 3 weeks led to reduced cell proliferation 2 hours after the stress procedure. Interestingly, this stress-induced effect did not persist and was no longer detected 24 hours later. Also, while chronic foot-shock stress had no impact on survival of hippocampal cells that were born before the stress procedure, it led to a decreased number of doublecortin-positive granule neurons that were born during the chronic stress period. Thus, whereas a strong activation of the HPA axis during acute foot-shock stress is not sufficient to reduce hippocampal cell proliferation, repeated exposure to stressful stimuli for prolonged period of time ultimately results in dysregulated neurogenesis. In sum, this study supports the notion that chronic stress may lead to cumulative changes in the brain that are not seen after acute stress. Such changes may indicate compromised brain plasticity and increased vulnerability to neuropathology.

Rapid shrinkage of rat striatal extracellular space after local kainate application and ischemia as recorded by impedance.

Early changes in tissue extracellular space following exposure to the excitotoxin kainate in the striatum were compared to those following cardiac arrest of rats anesthetized by chloral hydrate. Tissue extracellular space was monitored by impedance measurements. The possible role of voltage-sensitive Na channels and energy metabolism was studied by local and systemic application of tetrodotoxine (TTX) and glucose, respectively. After both kainate intoxication and cardiac arrest the extracellular space (normally about 20%) became less than one-half within 15 min. TTX caused a delay in the effect of cardiac arrest, and a slight attenuation of that of kainate. Glucose was ineffective in both preparations. Parallel to a decrease in the extracellular space whole tissue Na/K ratio increased. These experiments show that excitotoxins and cardiac arrest cause similar (and not additive) changes in the extracellular space and that these changes are not mediated by Na channels. In cardiac arrest the onset of the extracellular space alterations is triggered by Na+ influx, thus presumably by neurotransmitter release. It is suggested that most (if not all) currently described protective measures against ischemic, hypoxic, or hypoglycemic brain damage are based on a prolongation of the time of onset leading to cell depolarization, rather than suppressing damaging processes during depolarization.

Regional calcium accumulation and cation shifts in rat brain by kainate.

Following local application of kainic acid, changes in the contents of Na+, K+, Ca2+, and Mg2+ of the striatum, cerebellum, and hippocampus of the rat were observed at various times after surgery. Within 1 h the levels of K+ decreased 20% whereas the levels of Na+ and Ca2+ increased at least 50% and 20%, respectively. These changes persisted for more than 8 weeks. Ca2+ levels rose further, to more than 10-fold during 8 weeks. The Mg2+ levels were slightly and only transiently decreased. Unilateral injections of kainate into the striatum affected the contents of these cations not only in this area, but also in the overlying cerebral cortex, the olfactory tubercle, and the ipsilateral substantia nigra. The Ca2+ increases were less when rats were kept on a diet deficient in Ca2+ and vitamin D. 45Ca2+, intravenously administered, accumulated significantly more in the kainate-lesioned striatum and substantia nigra than in the homotopic contralateral areas. Electron microscopic examination of the localization of Ca2+ with the oxalate-pyroantimonate technique showed the appearance of extracellularly located deposits and the accumulation of Ca2+ in (possibly degenerating) myelinated axons in kainate-lesioned striata. This study provides evidence that calcification of cerebral tissue is closely associated with neurodegenerative processes and shows that kainate may serve as a tool to elucidate the mechanism of brain calcification. The results are discussed in relation to idiopathic calcinosis (striopallidodentate calcinosis, Fahr's disease).