Movement disorders after hypoxic brain injury following cardiac arrest in adults.

BACKGROUND AND PURPOSE: Post-hypoxic movement disorders and chronic post-hypoxic myoclonus are rare complications after cardiac arrest in adults. Our study investigates the clinical spectrum, neuroimaging results, therapy and prognosis of these debilitating post-hypoxic sequelae. METHODS: This retrospective study included 72 patients from the neurological intensive care unit at a university hospital, who were diagnosed with hypoxic-ischaemic encephalopathy after cardiac arrest between January 2007 and September 2018. Clinical records were screened for occurrence of post-hypoxic movement disorders and chronic post-hypoxic myoclonus. Affected patients were further analysed for applied neuroprognostic tests, administered therapy and treatment response, and the outcome of these movement disorders and neurological function. RESULTS: Nineteen out of 72 screened patients exhibited post-hypoxic motor symptoms. Basal ganglia injury was the most likely neuroanatomical correlate of movement disorders as indicated by T1 hyperintensities and hypometabolism of this region in magnetic resonance imaging and positron emission tomography computed tomography. Levomepromazine and intrathecal baclofen showed first promising and mostly prompt responses to control these post-hypoxic movement disorders and even hyperkinetic storms. In contrast, chronic post-hypoxic myoclonus best responded to co-application of clonazepam, levetiracetam and primidone. Remission rates of post-hypoxic movement disorders and chronic post-hypoxic myoclonus were 58% and 50%, respectively. Affected patients seemed to present a rather good recovery of cognitive functions in contrast to the often more severe physical deficits. CONCLUSIONS: Post-hypoxic movement disorders associated with pronounced basal ganglia dysfunction might be efficiently controlled by levomepromazine or intrathecal baclofen. Their occurrence might be an indicator for a more unfavourable, but often not devastating, neurological outcome.

"Heidelberg standard examination" and "Heidelberg standard procedures" - Development of faculty-wide standards for physical examination techniques and clinical procedures in undergraduate medical education.

The competent physical examination of patients and the safe and professional implementation of clinical procedures constitute essential components of medical practice in nearly all areas of medicine. The central objective of the projects "Heidelberg standard examination" and "Heidelberg standard procedures", which were initiated by students, was to establish uniform interdisciplinary standards for physical examination and clinical procedures, and to distribute them in coordination with all clinical disciplines at the Heidelberg University Hospital. The presented project report illuminates the background of the initiative and its methodological implementation. Moreover, it describes the multimedia documentation in the form of pocketbooks and a multimedia internet-based platform, as well as the integration into the curriculum. The project presentation aims to provide orientation and action guidelines to facilitate similar processes in other faculties.

Nonviral gene delivery of erythropoietin by mesenchymal stromal cells.

Erythropoietin (EPO) acts on erythroblasts in the bone marrow (BM) to stimulate the formation of red blood cells. In this study, we wanted to determine whether BM-derived mesenchymal stromal cells (MSCs) can be used as cellular vehicles to deliver EPO in mice without the use of viral vectors. After isolation and characterization of murine MSCs (mMSCs), different transient transfection procedures were compared for their efficacy of gene transfer of the pEGFP-N2 plasmid. Nucleofection outperformed magnetofection and lipofection. Stably transfected mMSCs were generated by selection with G418-disulfate and single-cell-colony-forming unit (sc-CFU) assays without changes in their proliferation capacity and osteogenic/adipogenic differentiation potential. Next, murine EPO was stably introduced into mMSCs by nucleofection of a plasmid encoding the epo and egfp genes. Intraperitoneal transplantation of EPO-expressing mMSCs increased serum EPO levels, hematocrit and hemoglobin of C57BL/6 mice within 1 week. The hematocrit remained elevated for 5 weeks, but production of antibodies against both transgenes was detected in the hosts and serum EPO levels normalized. Our results suggest that nonviral gene delivery into MSCs can be used to enhance the known beneficial effects MSCs by additional production of therapeutic factors like EPO in vivo.

[Wound botulism after drug injection]. / Wundbotulismus nach Drogeninjektion.

CLINICAL PRESENTATION: A 32-year old male drug user presented with diplopia, ataxia and general weakness. The patient had abscesses on arms and legs at injection sites, bilateral ptosis, a bifacial weakness, nasal speech, severely reduced ability to raise his arms and a positive Trendelelenburg sign with normal motor neuron reflexes and normal sensation. CLINICAL AND LABORATORY TESTS: The haematological values indicated a hypochromic, microcytic anaemia (12,1 mg/dl), a slight leuko (10,8 G/L) - and thrombocytosis (582G/l) with elevated erythrocyte sedimentation rate (74 mm/h), and a reduced prothrombin time (67%). The HIV test was negative. The MRI scan of the brain and the bacterial, serological and cytological results of a lumbar puncture were normal. In the bloodculture no bacterial growth and no botulinum toxin was found. In a culture of the wound material grew coagulase-negative staphylococcus and Clostridium perfringens, diagnosed with PCR. The serum anti-acethylcholine antibodies were negative. The motor-nerve conduction test with repetitive stimulation of the ulnari nerve with a 3 Hz trigger showed no change in the amplitude, while a 20 Hz trigger showed an increment up to 160 %. DIAGNOSIS, TREATMENT AND RESPONSE TO THERAPY: Another possible diagnosis was excluded through MRI, CSF and serum examination. The typical presentation of a rapidly progressive descending paralysis without loss of sensation and the typical motor-nerve conduction disorder of a presynaptic block established the diagnosis of wound botulism. This was treated immediately by surgical removal of wound debris, antitoxin- and penicillin therapy. After 28 days the patient left the hospital with slight residual problems. He had been admitted to the intensive care unit for a short period only and intubation was not necessary at any time. CONCLUSION: After exclusion of any other possible diagnosis, it is possible to establish an early diagnosis of injection related wound botulism by its typical symptoms and signs. These are presented as wound abcesses at intramuscular drug injection sites together with rapidly progressive descending paralysis with preserved sensation. Treatment consists of surgical excision of wound debris combined with antitoxin and penicillin administration in order to prevent a possible build-up of residues. Early diagnosis and associated therapy overcome the necessity of intubation and prolonged intensive care.

Preventive magnesium supplement reduces ischemia-induced hearing loss and blood viscosity in the guinea pig.

The effect of magnesium (Mg) on ischemia-induced hearing loss was investigated in two groups of adult pigmented guinea pigs of either an optimal or suboptimal (physiologically high or low) Mg status maintained by different diets. Total Mg concentrations of the perilymph, cerebrospinal fluid, blood plasma and red blood cells were found to differ significantly between the two groups, as tested in a previous study. Local vascular impairment was produced by unilateral ferromagnetic thrombosis of cochlear blood vessels. Cochlear blood flow (CBF) and hearing function were measured using laser Doppler flowmetry and auditory brain-stem response audiometry, respectively. Ferromagnetic thrombosis resulted in significant reductions of the mean apical CBF in both experimental groups and of the mean basal CBF in the low Mg group compared to the contralateral ears. In the high Mg group, the basal CBF was not decreased. However, the laser Doppler signals revealed considerable interindividual variations and the differences found between the two experimental groups were not significant. In contrast, the hearing loss in the low Mg group was significantly higher than that in the high Mg group. A correlation was found to exist between the vascular impairment and the hearing threshold shift. In a separate series, we also tested the effect of Mg on hemorheology and found both the blood viscosity and blood viscoelasticity to be significantly lower in the high Mg group than in the low Mg group, depending on the shear rates tested. The present findings show that a preventive oral Mg supplement can significantly reduce the rate of ischemia-induced hearing loss and improve blood viscosity in the guinea pig.

Preventive effect of magnesium supplement on noise-induced hearing loss in the guinea pig.

The effect of magnesium (Mg) on noise-induced hearing loss was investigated in two groups of adult pigmented guinea pigs maintained either on optimal or suboptimal (physiologically high or low) Mg produced by different diets. The total Mg concentrations of the perilymph (PL), cerebrospinal fluid, blood plasma and red blood cells were measured by atomic absorption spectrometry and were found to differ significantly between the two groups (P < 0.01). One ear of each animal was exposed to either a single shooting impulse at a peak pressure level of 187 dB or two impulse noise series at a rate of 1/s and peak pressure levels of 150 dB (1,000 impulses) and 167 dB (2,280 impulses), respectively. Temporary (TTS) and permanent (PTS) hearing threshold shifts in anesthetized animals were measured 2 h and 1 week after the noise exposure, using auditory brain stem response (ABR) audiometry at a frequency range from 3.75 to 30 kHz. Exposure to the single noise impulse resulted in a mean TTS that was significantly lower in the high Mg group than that in the low Mg group (P < 0.05), although no substantial PTS was observed in either group. In the animals exposed to 150 dB noise, the TTS showed a tendency towards an Mg-related reduction at the higher frequencies. A small difference in PTS was found between the low Mg and high Mg groups, but was not significant. Exposure to the 167-dB noise series caused a considerable TTS, which was significantly lower in the high Mg group at 7.5 and 15 kHz than in the low Mg group (P < 0.05). The mean PTS showed a significant difference between the two Mg groups over the whole frequency range (P < 0.05) and was found to correlate negatively with the total Mg concentrations of both PL and plasma (P < 0.05). Moreover, the high Mg group showed a faster recovery from the hearing threshold shift than the low Mg group. The present findings show that preventive oral Mg supplements can significantly reduce the rate of acoustic trauma caused by high-level impulse noise exposure in the guinea pig.

Total magnesium concentrations of perilymph, cerebrospinal fluid and blood in guinea pigs fed different magnesium-containing diets.

The total magnesium (Mg) concentrations of the perilymph (PL), cerebrospinal fluid (CSF), plasma and red blood cells (RBCs) of anesthetized guinea pigs separated into three groups and fed different Mg-containing diets were determined by atomic absorption spectrometry. Due consideration was given to the significant sources of error connected with the sampling procedure, particularly contamination of PL with CSF. The Mg levels of the individuals fluids differed significantly (P < 0.05/0.01) within each group. In the normal Mg group, the mean values of the PL, CSF and plasma were 0.66, 0.81 and 0.97 mmol/l, respectively, and 7.83 mmol/kg dry weight for RBCs. The analytical data were found to depend on the Mg content of the animals' diet, but to a different degree in the individual specimens (plasma > PL > CSF). A correlation was found to exist between all specimens tested (P < 0.05/0.01), except for CSF and RBCs, with the closest relation being that between plasma and PL. These findings suggest that the perilymphatic Mg equilibrates with the Mg level of plasma rather than with that of CSF. This is the first report showing Mg data of PL, CSF, plasma and RBCs obtained from the same subject, and the dependency on the Mg content of the animals' diet.

Improvement in inner ear blood flow by nitric oxide following experimentally induced cochlear thrombosis in anesthetized guinea pigs.

The nitric oxide (NO) donor sodium nitropruside (SNP) applied to the round window membrane has recently been found to increase cochlear blood flow (CoBF) in normal guinea pigs and in normal and presbyacusic mice. This study examined the effect of topical applications of SNP on experimentally impaired CoBF in anesthetized guinea pigs. Small (3 microliters) portions of 3% SNP were applied to the round window niche of both normal and thrombosed cochleas. Local vascular impairment was produced by ferromagnetic thrombosis of cochlear blood vessels and the microcirculation measured using laser Doppler flowmetry. Ferromagnetic thrombosis resulted in a mean decrease of CoBF to 52% of baseline. There was a clear improvement in mean CoBF to 84% of baseline by the topical application of SNP that depended on the degree of ischemic damage produced. Under neuroleptanalgesia and ketamine-xylazine anesthesia, significant increases in CoBF were measured in normal ears as well as in the thrombosed ones. However, several SNP applications were needed to improve the impaired CoBF, while a single portion was sufficient in the normal cochlea to cause a drastic increase in mean CoBF to 234% of baseline. In urethane-anesthetized animals, no flow increase was found despite repeated drug administration. Careful evaluation of the laser Doppler signals was necessary to accurately determine the concentrations of the moving blood cells and their mean velocities.

Laser Doppler measurements of inner ear blood flow during experimental thrombosis of cochlear blood vessels in the guinea pig.

This study investigated the vascular effect of ferromagnetic obstruction of cochlear blood vessels in the guinea pig using dual-channel laser Doppler flowmetry. To improve this technique, we tested new types of magnets and iron spheres. In so doing, the cochlear temperature was lowered selectively and general hypothermia was avoided. The success of vascular impairment in the inner ear was found to depend on the experimental conditions used. Given normothermic conditions (38 degrees C body temperature), a clear reduction in cochlear blood flow (CBF) was found in only about 30% of the animals tested when an aluminium-nickel-cobalt alloy magnet and carbonyl iron spheres were used, while this ratio increased to about 80% under general hypothermia (33 degrees C). Using a stronger neodymium-iron-boron magnet and smaller-sized iron spheres, we found the success of vascular obstruction to be approximately 70% under normothermia and 100% with local hypothermia (to 33 degrees C) of the cochlea. Although the extent of vascular impairment revealed a considerable interindividual variation, the present findings demonstrate that ferromagnetic intervention in CBF with dual-channel laser Doppler flowmetry can be used to investigate the effect of quantified cochlear ischemia on inner ear physiology in the guinea pig model and test various therapeutic strategies.

Effects of experimental cochlear thrombosis on oxygenation and auditory function of the inner ear.

To elucidate the etiology and pathogenesis of sudden hearing loss, the effect of experimental cochlear thrombosis on oxygenation and the auditory function of the inner ear was investigated in anesthetized guinea pigs. Impairment of cochlear blood flow (CBF) was induced by ferromagnetic obstruction of cochlear blood vessels at lowered body temperature. Perilymphatic oxygen partial pressure (PO2) in the basal scala tympani (about 200 microm below the round window membrane) was measured polarographically using micro-coaxial needle electrodes. Auditory function was examined by recording cochlear microphonic (CM) frequency responses, compound action potentials (CAP) and auditory evoked brainstem responses (ABR). Findings demonstrated a considerable decrease in the mean perilymphatic PO2 of 40%, 2 h after the start of the experiment. Mean CM and N1 CAP amplitudes were reduced by about 25% each and ABR by 18%. No significant changes were observed in the latencies of either CAP or ABR. Mean basal CBF was found to decrease by 35%, as measured by laser Doppler flowmetry in a parallel study. The present findings demonstrate that vascular impairment in the inner ear results in a considerable drop in intracochlear oxygenation, causing a significant loss in the auditory response.

Changes in cochlear oxygenation, microcirculation and auditory function during prolonged general hypoxia.

Changes in cochlear microcirculation and oxygenation and auditory function were examined in anesthetized guinea pigs during prolonged hypoxic ventilation (8% oxygen in nitrogen) for 1 h. Cochlear blood flow and perilymphatic oxygen partial pressure were measured using laser Doppler flowmetry and oxygen-sensitive microelectrodes. Auditory function was examined by recording cochlear microphonics, compound action potentials and auditory evoked brainstem response. Blood pressure and heart rate were monitored. During systemic hypoxia, the perilymphatic PO2 dropped on average to about 70% of the initial value. Cochlear and brainstem potentials showed a mean reduction to 75-82%. Different effects of hypoxia on cochlear blood flow were observed and included decreases as well as increases. Mean arterial blood pressure declined significantly during hypoxia, while the heart rate remained constant. The changed variables returned to normal during reventilation with room air. The findings are discussed with regard to their significance as an animal model for the study of hypoxia-induced cochlear pathophysiology.

Intensity-related changes in cochlear blood flow in the guinea pig during and following acoustic exposure.

This study examined the effects of acoustic exposure at different intensities on cochlear blood flow (CBF) using laser Doppler flowmetry. CBF was measured in anesthetized guinea pigs exposed to either a 10 kHz pure tone at 125, 105, or 90 dB SPL, or wide-band noise at 85 dB SPL for 1 h. Mean arterial blood pressure and heart rate were recorded continuously. Arterial acid-base status, cochlear temperature, cochlear microphonics (CM), and compound action potentials (CAP) were measured before and after exposure. There was a small, but significant, steady decline in basal CBF after 40 min loud sound exposure (125 dB SPL), but no change in basal CBF occurred with the lower intensities (85-105 dB SPL). In contrast, there was a significant increase in apical CBF after 1 h exposure to either moderate wideband noise (85 dB SPL) or a 10 kHz tone at 105 dB SPL. These changes persisted during a 20-min post-exposure period. In most cases, the cochlear temperature and cardiorespiratory variables monitored remained unchanged during and after the exposures as compared to the controls. CM and CAP amplitudes showed extensive losses after acoustic overstimulation (125 dB SPL), but no permanent changes were found at the lower intensities used. The present findings confirm the occurrence of intensity-related effects of acoustic exposure on the cochlear microcirculation.

Intensity-dependent changes in oxygenation of cochlear perilymph during acoustic exposure.

This study examined the effects of acoustic exposure at different intensities on local oxygenation of the cochlea. The oxygen partial pressure (pO2) of perilymph in the basal scala tympani was measured polarographically in anesthetized guinea pigs exposed to either wide-band noise at 85 dB SPL or a 10 kHz pure tone at 90, 105, or 125 dB SPL for 1 h. Cochlear temperature, heart rate, arterial blood pressure and acid-base status were monitored. The cochlear microphonics (CM) and compound action potentials (CAP) were recorded before and after exposure. There were clear intensity-dependent differences in the effect of acoustic exposure on perilymphatic oxygenation. Moderate exposure intensities (85-90 dB SPL) were found to increase the pO2 by an average of about 20% of the initial level. In contrast, high intensity acoustic exposure (125 dB SPL) resulted in a mean decrease of about 20%. These changes persisted within a subsequent 30-min post-exposure period. There was no significant change in cochlear temperature and cardiorespiratory variables during and after any of the exposures as compared to the controls. CM and CAP amplitudes showed an extensive loss after acoustic overstimulation (125 dB SPL), but no permanent change with lower exposure intensities. These findings suggest that intracochlear oxygenation plays an important role in inner ear physiology during acoustic stimulation.

Measurements of perilymphatic oxygen tension in guinea pigs exposed to loud sound.

Using different types of custom-made oxygen-sensitive microelectrodes, the perilymphatic oxygen partial pressure (PO2) was determined in anesthetized guinea pigs. Cochlear temperature, heart rate, and arterial blood pressure and acid-base status were monitored. The PO2 in the basal scala tympani perilymph (200 microns below the round window membrane) was found to be 53 +/- 17 mmHg (mean +/- SD) in 33 normal animals. In 11 guinea pigs exposed to loud sound for 15 min (10 kHz pure tone, 125 dB SPL) there was on average a continuous decline in the perilymphatic PO2, which was significant only 30 min post-exposure. A considerable variation in response was found in individual animals. Mean arterial blood pressures showed a slightly increasing time course, while heart rates did not change significantly during the whole period of the experiment. Arterial acid-base status and PO2 values remained within normal limits and did not change significantly. Cochlear microphonics and compound action potentials were substantially decreased after acoustic overstimulation. The results are discussed with due consideration of sources of error.

Cochlear blood flow following temporary occlusion of the cerebellar arteries.

In order to induce acute transient local blood flow impairment in the guinea pig cochlea, terminal vessels arising from the proximal and middle third of the basilar artery and from the rostral part of the collateral vertebral artery near their junction were occluded by temporary (1-2 min) compression. Clear identification of the anterior inferior cerebellar artery was impeded due to great variation in branching of the cerebellar arteries. To quantify the effect of the vascular occlusion on the cochlear microcirculation, laser Doppler flowmetry was used. Successive compression of the cerebellar arteries resulted in individually differentiated effects on the Doppler signal from the cochlea. In about half of the experiments there was a decrease in the laser signal to 25-55% of the initial level, while in the other cases no clear decrease occurred. Proximal obstruction of the basilar artery was found to reduce the cochlear blood flow up to 10-25% of its initial level, indicating that the Doppler signal primarily reflects microcirculation within the membranous cochlea. The findings are discussed with regard to their significance as an animal model for acute transient cochlear hypoxia.

Laser light transmission and laser Doppler blood flow measurements on the human, rat and guinea pig cochlea.

In order to test the applicability of laser-Doppler flowmetry in monitoring cochlear blood flow clinically, the thickness and the helium-neon laser light transmission of specimens of human, rat and guinea pig promontory bone and human skin were determined. Furthermore, comparative laser-Doppler measurements were taken from the promontory in patients, rats and guinea pigs. Due to the different thicknesses of the promontory bone in different species, the light transmission was found to be considerably higher for the animal cochlea (rat, 15%; guinea pig, 6.6%) than the human cochlea (1.7%). However, a clearly higher laser-Doppler signal was recorded from both the human and the rat cochleas as compared with the guinea pig. The relative laser light attenuation by the human skin specimens corresponded to that of the human promontory bone. The findings are discussed with regard to the suitability of the laser-Doppler method for blood flow measurements in the human cochlea.

Laser Doppler measurements of cochlear blood flow during loud sound presentation.

The laser Doppler flowmeter may give responses to loud sound that reflect the vibration of cochlear structures rather than changes in cochlear blood flow. The present study demonstrates that the positive artifactual response (i.e., increased flow reading) to sound at frequencies above approximately 5 kHz can be eliminated by using flowmeters which have electronic filters at 4 and 12 kHz, limiting the bandwidth of the optical Doppler shifted frequency range to lower frequencies. However, when using the 4 kHz filter a "residual" immediate negative response to loud high-frequency sound (10 kHz tone at 125 dB SPL) is evident at the beginning of the exposure. These findings are discussed with regard to the suitability of the method for investigating the effect of sound/noise on cochlear blood flow.

[Physiological parameters of guinea pigs under long-term anesthesia with controlled respiration]. / Physiologische Parameter des Meerschweinchens unter Langzeitnarkose mit kontrollierter Beatmung.

56 guinea pigs were anesthetized with a mixture of alpha-chloralose and a small dose of ethyl urethane injected i.p. in order to compare the chloralose-urethane anesthesia with neuroleptanesthesia, a mixture of droperidol-fentanyl and a small induction dose of Na-pentobarbital was injected i.p. to 14 animals. All animals were maintained at constant body temperature of 38 degrees C and artificially respirated via a tracheal cannula monitoring the end expiratory CO2 concentration. Mean arterial blood pressure (carotid artery) and heart rate were continuously recorded. Arterial acid-base status and pO2 were tested. Mean arterial blood pressure and heart rate were found to be somewhat higher in the neuroleptanesthetized animals. Under chloralose-urethane anesthesia and neuroleptanesthesia the mean arterial blood pressure amounted to 56 and 62 mm Hg, respectively. These findings correspond to data given in the literature concerning the mean pressure in unanesthetized guinea pigs. The mean heart rates of 295 and 316 min-1, respectively are somewhat higher compared to the normal range. Under both anesthesias, the arterial acid-base status was within the normal limits of unanesthetized animals. The mean arterial pO2 of 80.9 and 76.5 mm Hg was relatively low. The present studies have shown that chloralose-urethane as well as droperidol-fentanyl with pentobarbital are useful, under controlled artificial respiration, to achieve long-term anesthesia maintaining nearly normal systemic circulatory and respiratory conditions.

Sound-induced artifact in cochlear blood flow measurements using the laser Doppler flowmeter.

The laser Doppler flowmeter has been shown to give a response from the cochlea during high intensity acoustic stimulation which is not related to blood flow through the cochlea. The magnitude of this response depends upon the intensity and frequency of stimulation and the location of the probe on the cochlea. Evidence is presented that the response is derived from the vibration of cochlear tissue and/or the bony cochlear shell during acoustic stimulation.