Spatial learning induces predominant downregulation of cytosolic proteins in the rat hippocampus

Spatial learning is known to depend on protein synthesis in the hippocampus. Whereas the role of the hippocampus in spatial memory is established, the biochemical and molecular mechanisms underlying this process are poorly understood. To comprehend the complex pattern of protein expression induced by spatial learning, we analyzed alterations in the rat hippocampus proteome after 7 days of spatial learning in the Morris water maze. Forty Wistar rats were randomized into two groups. Animals of group A learned to localize a hidden platform in the water maze. Animals of group B served as controls and spent exactly the same time in the water maze as animals of group A. However, no platform was used in this test and the rats could not learn to localize the target. After the last trial, hydrophilic proteins from the hippocampus were isolated. A proteome-wide study was performed, based on two-dimensional gel electrophoresis and mass spectrometry. Compared with non-learning animals, 53 (70%) proteins were downregulated and 23 (30%) proteins were upregulated after 7 days in rats with spatial learning. The overall changes in protein expression, as quantified by the induction factor, ranged from -1.62 (downregulation to 62%) to 2.10 (upregulation by 110%) compared with controls (100%). Most identified proteins exhibit known functions in vesicle transport, cytoskeletal architecture, and metabolism as well as neurogenesis. These findings indicate that learning in the Morris water maze has a morphological correlate on the proteome level in the hippocampus.

Non-suppurative meningoencephalitis of unknown origin in cats and dogs: an immunohistochemical study

Non-suppurative meningoencephalitis of unknown cause is a frequent finding in dogs and cats. Fifty-three dogs and 33 cats with non-suppurative meningoencephalitis of unknown aetiology were examined immunohistochemically for 18 different infectious agents, including viruses, bacteria and prion protein^Sc. In 14 (26%) of the dogs and 13 (39%) of the cats a causative agent was identified in the central nervous system (CNS), two dogs and one cat giving positive results for two infectious agents simultaneously. The study revealed infections with known causative agents (porcine herpes virus 1, feline infectious peritonitis virus, Escherichia coli) and a new disease pattern of parvovirus infection in the CNS of dogs and cats. Infection of the CNS with feline leukaemia virus was found in a cat. Five dogs and four cats gave positive results for West Nile virus (WNV) antigen. In one dog, canine parainfluenza virus antigen was detected in the brain. Four dogs and four cats gave positive results for encephalomyocarditis virus (EMCV). The significance of the detection of WNV and EMCV antigen requires further study. The aetiology remained undetermined in 39 dogs (74%) and 20 cats (61%). Although it is possible that non-infectious causes play a more important role than previously thought, infections with hitherto unrecognized agents cannot be ruled out.

[The new 2005 resuscitation guidelines of the European Resuscitation Council: comments and supplements]

The new CPR guidelines are based on a scientific consensus which was reached by 281 international experts. Chest compressions (100/min, 4-5 cm deep) should be performed in a ratio of 30:2 with ventilation (tidal volume 500 ml, Ti 1 s, FIO2 if possible 1.0). After a single defibrillation attempt (initially biphasic 150-200 J, monophasic 360 J, subsequently with the respective highest energy), chest compressions are initiated again immediately for 2 min. Endotracheal intubation is the gold standard; other airway devices may be employed as well depending on individual skills. Drug administration routes for adults and children: first choice IV, second choice intraosseous, third choice endobronchial [epinephrine dose 2-3x (adults) or 10x (pediatric patients) higher than IV]. Vasopressors: 1 mg epinephrine every 3-5 min IV. After the third unsuccessful defibrillation attempt amiodarone IV (300 mg); repetition (150 mg) possible. Sodium bicarbonate (1 ml/kg 8.4%) only in excessive hyperkalemia, metabolic acidosis, or intoxication with tricyclic antidepressants. Consider atropine (3 mg) and aminophylline (5 mg/kg). Thrombolysis during spontaneous circulation only in myocardial infarction or massive pulmonary embolism; during CPR only during massive pulmonary embolism. Cardiopulmonary bypass only after cardiac surgery, hypothermia or intoxication. Pediatrics: best improvement in outcome by preventing cardiocirculatory collapse. Alternate chest thumps and chest compression (infants), or abdominal compressions (>1-year-old) in foreign body airway obstruction. Initially five breaths, followed by chest compressions (100/min; approximately 1/3 of chest diameter): ventilation ratio 15:2. Treatment of potentially reversible causes (4 "Hs", "HITS": hypoxia, hypovolemia, hypo- and hyperkaliemia, hypothermia, cardiac tamponade, intoxication, thrombo-embolism, tension pneumothorax). Epinephrine 10 microg/kg IV or intraosseously, or 100 microg (endobronchially) every 3-5 min. Defibrillation (4 J/kg; monophasic oder biphasic) followed by 2 min CPR, then ECG and pulse check. Newborns: inflate the lungs with bag-valve mask ventilation. If heart rate<60/min chest compressions:ventilation ratio 3:1 (120 chest compressions/min). Postresuscitation phase: initiate mild hypothermia [32-34 degrees C for 12-24 h; slow rewarming (<0.5 degrees C/h)]. Prediction of CPR outcome is not possible at the scene; determining neurological outcome within 72 h after cardiac arrest with evoked potentials, biochemical tests and physical examination. Even during low suspicion for an acute coronary syndrome, record a prehospital 12-lead ECG. In parallel to pain therapy, aspirin (160-325 mg PO or IV) and in addition clopidogrel (300 mg PO). As antithrombin, heparin (60 IU/kg, max. 4000 IU) or enoxaparine. In ST-segment elevation myocardial infarction, define reperfusion strategy depending on duration of symptoms until PCI (prevent delay>90 min until PCI). Stroke is an emergency and needs to be treated in a stroke unit. A CT scan is the most important evaluation, MRT may replace a CT scan. After hemorrhage exclusion, thrombolysis within 3 h of symptom onset (0.9 mg/kg rt-PA IV; max 90 mg within 60 min, 10% of the entire dosage as initial bolus, no aspirin, no heparin within the first 24 h). In severe hemorrhagic shock, definite control of bleeding is the most important goal. For successful CPR of trauma patients, a minimal intravascular volume status and management of hypoxia are essential. Aggressive fluid resuscitation, hyperventilation, and excessive ventilation pressure may impair outcome in severe hemorrhagic shock. Despite bad prognosis, CPR in trauma patients may be successful in select cases. Any CPR training is better than nothing; simplification of contents and processes remains important.

[Retropharyngeal tendinitis. Differential diagnosis in the management of acute neck pain]

Neck pain is frequent and can be a symptom of numerous differential diagnoses with quite different diagnostic and therapeutic consequences. A 37-year-old woman reported acute neck pain aggravated by movements of the cervical spine and head and by swallowing. Clinical examination showed pronounced neck stiffness. T2-weighted MRI demonstrated high-intensity edema and effusion localized prevertebrally in the area of the superior part of the longus colli muscle. Computed tomography of this region demonstrated prevertebral calcification leading to the diagnosis of retropharyngeal tendinitis. Nonsteroidal antiphlogistic drugs led to rapid improvement of clinical signs and symptoms. Retropharyngeal tendinitis should be considered in patients with acute neck pain.

[Management and causes of pneumocephalus. Case report and review of the literature]

Pneumocephalus is commonly seen after head and facial trauma, tumors of the skull base, after neurosurgery or otorhinolaryngology, and rarely spontaneously. Venous air embolism can result from right-to-left shunting or pneumocephalus. We report two cases of pneumocephalus, one after surgery of the paranasal sinus and the other after transabdominal prostatectomy. Clinical signs of the pneumocephalus were headache followed by epileptic seizures and, respectively, severely impaired consciousness after the operation. Treatment was either revision of the skull base with craniotomy or conservative therapy of the brain edema. Based on these case reports and the medical literature on pneumocephalus, we review the causes and treatment of this rare condition.

Therapy of Severe Ischemic Stroke: Breaking the Conventional Thinking

Large hemispheric infarcts must be recognized in the emergency department as a life-threatening condition that requires prompt and massive intervention. After stabilization of the airway, breathing, and circulation, the initial diagnostic work-up and transfer to a neurointensive care unit should not be delayed. Today several new therapeutic options can be offered. Surgical decompression seems to be effective in lowering increased intracranial pressure, preventing transtentorial herniation and reducing mortality in patients with malignant middle cerebral artery infarction. Another option may be therapeutic hypothermia, which has been found to be neuroprotective in animal models, as well as in clinical studies after cardiac arrest. Experience in stroke patients suggest that hypothermia may offer a new approach for the treatment of acute cerebral ischemia.

[Hypertensive encephalopathy: differential diagnosis of brain edema with midline shift]

Hypertensive encephalopathy is a severe complication of hypertensive crisis or malignant hypertonia. We report a case with grave clinical and radiological features. The patient was comatose, with pupillary dysfunction, and initial CT suggested a local intracranial mass with edema. Cranial MRI showed almost completely hyperintensive supratentorial white matter, with edema and midline shift, and hypertensities in cerebellum and brainstem. The patient recovered, and the radiological findings improved after antihypertensive therapy. Hypertensive encephalopathy may be differentiated by MRI, manifests acutely, and is potentially reversible when adequate therapy is rapidly performed.

Effect of corticosteroids on short-term and long-term memory

The effect of acute high-dose glucocorticoid therapy on memory function in patients with acute optic neuritis (n = 9) and multiple sclerosis (n = 21) was studied. All patients had reversible impairment of long-term memory functions, whereas measures of short-term memory, attentional functions, and alertness remained unaffected.