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Biomedical subjects

S Schwab

Publications and source records attributed to S Schwab.

At least 19 recordsLinked to original sources

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.

Animals↗

[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.

Adult↗

[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.

Anisocoria↗

[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.

Acute Disease↗

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.

Barbiturates↗

IV thrombolysis in patients with acute stroke due to spontaneous carotid dissection.

The authors reviewed the histories of 33 patients (ages 44 to 50 years) treated with IV thrombolysis for acute stroke due to spontaneous cervical carotid artery dissection. Median NIH Stroke Scale (NIHSS) score on admission was 15. No new or worsened local signs, subarachnoid hemorrhage, pseudoaneurysm formation, or rupture of the cervical ICA were observed. At 3 months, median NIHSS was 7 and median modified Rankin Scale (mRS) 2.5; mRS < or = 2 was observed in 17 patients.

Adult↗

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.

Adolescent↗

[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.

Adult↗

Does acute occlusion of the carotid T invariably have a poor outcome?

OBJECTIVE: To evaluate the prognosis of patients with acute occlusion of the carotid T. METHODS: The authors studied 42 consecutive patients with acute carotid T occlusion, age 66 (59 to 74) years (median [interquartile range]). T occlusion was diagnosed with transcranial Doppler sonography (TCD; n = 11) and MR (n = 28) or CT (n = 3) angiography. Final infarction size was evaluated on follow-up CT 3 to 7 days after symptom onset and recanalization by follow-up TCD 24 to 36 hours after symptom onset. RESULTS: NIH Stroke Scale (NIHSS) score on admission was 18 (16 to 20). Final infarct size was one-third or less of the middle cerebral artery (MCA) territory in 11, greater than one-third but less than or equal to two-thirds of the MCA territory in 10, and greater than two-thirds of the MCA territory in 21 patients. Modified Rankin Scale (mRS) score 6 months after stroke onset was 2 in 7 (17%), 3 in 2 (5%), 4 in 13 (31%), 5 in 7 (17%), and 6 in 13 (31%) patients. Complete or partial MCA recanalization within 24 hours after symptom onset was observed in 12 of 18 patients treated with thrombolysis and 4 of the remaining 24 patients (p = 0.001) and was associated with better clinical outcome (mRS 2, recanalization 6/7 [86%]; mRS 3 to 5, recanalization 8/22 [36%]; mRS 6, recanalization 2/13 [15%]; p = 0.01). Recanalization and NIHSS score on admission were independent predictors of outcome. CONCLUSIONS: Acute carotid T occlusion does not necessarily carry a poor prognosis. IV thrombolysis frequently results in recanalization, which is related to a better clinical outcome and smaller final infarction size.

Acute Disease↗

Effect of brain-derived neurotrophic factor treatment and forced arm use on functional motor recovery after small cortical ischemia.

BACKGROUND AND PURPOSE: Both the administration of growth factors and physical therapy such as forced arm use (FAU) are promising approaches to enhance recovery after stroke. We explored the effects of these therapies on behavioral recovery and molecular markers of regeneration after experimental ischemia. METHODS: Rats were subjected to photothrombotic ischemia: sham (no ischemia), control (ischemia), brain-derived neurotrophic factor (BDNF; ischemia plus BDNF, 20 microg), and FAU (ischemia plus FAU, 1-sleeve plaster cast ipsilateral limb). Animals survived 1 or 6 weeks and underwent behavioral testing (Rotarod, beam balance, adhesive removal, plantar test, neuroscore). After the rats were killed, brain sections were immunostained for semiquantitative analysis of MAP1B, MAP2, synaptophysin, GFAP expression, and quantification of infarct volumes. RESULTS: Infarct volumes were not different between the groups 1 or 6 weeks after ischemia. BDNF-treated animals had better functional motor recovery (Rotarod, beam balance, neuroscore) compared with all other groups (P<0.05). There was no significant adverse effect of early FAU treatment on motor recovery, although sensorimotor function (adhesive removal test) was impaired (P<0.05). There were no differences between groups as measured by nociception of the left and right forepaw (plantar test). BDNF treatment transiently induced MAP1B expression in the ischemic border zone and synaptophysin expression within the contralateral cortex 6 weeks after ischemia (P<0.05). Both BDNF and FAU reduced astrogliosis compared with controls (P<0.05). CONCLUSIONS: Postischemic intravenous BDNF treatment improves functional motor recovery after photothrombotic stroke and induces widespread neuronal remodeling. Early FAU treatment after stroke does not increase infarct size, impairs sensorimotor function, but leaves motor function unchanged. Postischemic astrogliosis was reduced by both treatments.

Animals↗

[Cerebral microdialysis in stroke].

Cerebral microdialysis is an invasive technique for neurochemical monitoring that has been established for neuro-critical disorders such as subarachnoid hemorrhage and severe brain injury. We present data on cerebral microdialysis in stroke patients which were obtained in an ongoing study supported by the German Ministry for Education and Research. So far, 50 patients have been included who required critical care due to massive stroke of the middle cerebral artery territory. By correlating the microdialysis results with follow-up CT scans, we could define the neurochemical characteristics of three different brain compartments: (1) noninfarcted brain tissue with normal microdialysis values, (2) brain areas adjacent to the infarct core which were not hypodense in CT scans but caused reversible neurochemical alterations, and (3) the infarct core with massive concentration changes which did not normalize over the measuring period of 3 to 5 days. Microdialysis values averaged over time and correlated with initial PET scans helped to describe neurochemical predictors of a malignant, i.e., life-threatening, space-occupying course of the ischemic stroke. We discuss the value of this method in guiding therapy and predicting clinical outcome in the context of other neurological critical care disorders and describe the pros and cons of cerebral microdialysis as an invasive monitoring technique.

Brain Edema↗

[Spontaneous intracerebral hemorrhages].

Spontaneous intracerebral hemorrhage (ICH) accounts for 8-15% of all cases of stroke and among patients receiving oral anticoagulants this number increases up to 40%. Mortality and morbidity are considerably higher in patients with ICH compared to patients with ischemic stroke. Large randomized controlled trials provide only little evidence for therapeutic strategies in patients with spontaneous ICH. In this review we summarize the available data and give recommendations on the management of spontaneous ICH.

Administration, Oral↗

Intrathecal baclofen for stiff-person syndrome: life-threatening intermittent catheter leakage.

Intrathecal baclofen (ITB) is used for unresponsiveness to other treatment for patients with stiff-person syndrome (SPS). The authors report a patient with SPS who developed acute and life-threatening baclofen withdrawal symptoms. Open surgery disclosed a small position-dependent leak in the catheter connector. This catheter failure was not detected by standard noninvasive checking methods.

Acute Disease↗

Neuroprotective effect of granulocyte colony-stimulating factor after focal cerebral ischemia.

BACKGROUND AND PURPOSE: The potential neuroprotective effect of the granulocyte colony-stimulating factor (G-CSF) after glutamate-induced excitotoxicity in cell culture and after focal cerebral ischemia in rats was studied. We hypothesized the existence of the G-CSF receptor (G-CSFR) as a main G-CSF effector on neurons, and immunohistochemistry, immunoblotting, and polymerase chain reaction were performed. The G-CSFR-mediated action was studied by activation of signal transducer(s) and activator(s) of transcription-3 (STAT3) in the periphery of the infarction. METHODS: Neuroprotection of various G-CSF concentrations on glutamate-induced excitotoxicity was studied in cell culture. In vivo, ischemia was induced by use of a suture occlusion model of the middle cerebral artery (90-minute occlusion) in the rat. Thirty minutes after the induction of ischemia, the animals (n=12 per group) received G-CSF at 60 microg/kg body wt IV for 90 minutes or vehicle (saline). Infarct volume was calculated on the basis of 2,3,5-triphenyltetrazolium chloride staining 24 hours after ischemia. Expression of the G-CSFR was studied by immunohistochemistry and verified by reverse transcription-polymerase chain reaction and immunoblotting. Expression of STAT3 was determined by immunohistochemistry. RESULTS: In cell culture, G-CSF exhibited a significant neuroprotective effect after glutamate-induced excitotoxicity (P<0.05). A G-CSF concentration of 10 ng/mL was maximally effective, resulting in a nearly complete protection. In vivo, G-CSF reduced infarct volume to 47% (132.0+/-112.7 mm3 versus 278.9+/-91.6 mm3 [P<0.05] in the control group). Immunohistochemistry, Western blotting, and reverse transcription-polymerase chain reaction revealed the existence of G-CSFRs in neurons and glial cells. Animals treated with G-CSF significantly upregulated STAT3 in the periphery of the infarction compared with control animals (P<0.05). CONCLUSIONS: G-CSF achieved a significant neuroprotective effect in cell culture and after intravenous administration after stroke. Increased STAT3 expression in the penumbra of G-CSF-treated rats suggests mediation by G-CSFR.

Animals↗

[Acute meningitis after transrectal prostate biopsy].

Acute meningitis caused by Escherichia coli is a rare disease in adulthood. Medical procedures, e.g. surgical interventions, have been described as a cause. Infection by blood transmission of fecal E. coli is also known. We report a case of acute meningitis after transrectal prostate biopsy. E. coli could be identified both in the cerebrospinal fluid and in the blood culture. A broad initial antibiotic therapy was administered. After cultural isolation of E. coli the therapy was switched to cefotaxime. The initially comatose patient recovered swiftly.

Acute Disease↗

[Bilateral vertebral artery dissection after chiropractic treatment].

A 31-year-old woman suffered a brainstem infarction secondary to chiropractic neck manipulation. A dissection of both vertebral arteries could be demonstrated by MR tomography. This case report should alert therapists to be aware of vertebrobasilar complications after spinal manipulations.

Adult↗

Neuroendocrine changes in patients with acute space occupying ischaemic stroke.

OBJECTIVE: To evaluate neuroendocrine changes in critical care patients with acute space occupying hemispheric stroke. METHODS: 22 patients with acute space occupying hemispheric stroke were studied (mean age 57.7 years; five women, 17 men). Plasma levels of prolactin, thyrotropin (TSH), total thyroxine (T4), free thyroxine (FT4), and total triiodothyronine (T3) were measured on admission and thereafter on days 3, 5, 7, and 9. Cortisol and ACTH levels were analysed at 8.00, 16.00, and 24.00 hours each day. A TRH stimulation test with measurements of TSH and prolactin was done on day 3. RESULTS: Nine patients underwent decompressive craniectomy and nine were treated with moderate hypothermia. All patients received vasopressor drugs because of arterial hypotension. Plasma ACTH and cortisol values were abnormally low despite systemic hypotension and acute systemic illness, and remained low throughout the observation period. The diurnal rhythm of cortisol was not preserved. Prolactin levels increased during the observation period, and were well above normal on day 9. Thyroid function was slightly suppressed until day 7. TRH stimulation of plasma TSH and prolactin was low. CONCLUSIONS: Patients with an acute space occupying cerebral infarct show profound neuroendocrine changes. The central regulation of adrenal and thyroid function and prolactin release is impaired, which may compromise the clinical course of affected patients and have implications for therapeutic management.

Adrenocorticotropic Hormone↗

[Clinical relevance of detection of microembolism signals with transcranial Doppler ultrasound diagnosis].

Detection of microembolic signals (MES) has been described in several patients groups. A potential clinical relevance of this technique has been established (1) during the first hours following carotid endarterectomy and (2) for patients with asymptomatic ICA stenosis or various autoimmune disorders. Intraoperative monitoring in patients undergoing cardiac or carotid surgery can be used to improve the surgical technique but provides no prognostic information for individual patients. Microembolic signals in patients with prosthetic heart valves cannot be used as markers for stroke risk; their potential significance as markers for neuropsychological deficits remains unclear. Recent reports suggest that MES can be used as surrogate markers for assessing the efficacy of antiplatelet agents. The fact that automated MES detection is not feasible greatly reduces the technique's applicability. On the whole, MES detection--with the exception of the patient groups listed above--provides pathophysiological rather than clinically relevant information.

Feasibility Studies↗