Biomedical subjects

Georg Becker

Publications and source records attributed to Georg Becker.

24 records · Page 2Linked to original sources

PubMed2002

Echogenicity of the substantia nigra: association with increased iron content and marker for susceptibility to nigrostriatal injury.

BACKGROUND: Patients with Parkinson disease characteristically exhibit an increased echogenicity of the substantia nigra (SN) on transcranial sonography, a new neuroimaging technique. The same echo feature of the SN can be identified in 9% of healthy adults. OBJECTIVE: To evaluate the relevance of the echogenic SN in healthy adults. DESIGN: In the first part of the study, 10 healthy subjects younger than 40 years with a distinct SN hyperechogenicity underwent extensive neurological, motor, neuropsychological, and fluorine 18-dopa positron emission tomographic ([18F]-dopa PET) examinations. Results were compared with those of 10 subjects with a low echogenic SN. In the second part of the study, the postmortem brains of 20 patients without extrapyramidal disorders during their lifetime were sonographically examined with a particular focus on SN echogenicity. Subsequently, one half of the brain was prepared for heavy metal analysis, the other for a histological examination. RESULTS: Healthy subjects with SN hyperechogenicity exhibited a significant reduction of the [18F]-dopa uptake, especially in the putamen (Wilcoxon matched pair test: left side, P =.006; right side, P =.009), whereas their neuropsychological and motor performance were normal. Postmortem studies showed that the echogenicity of the SN correlated with its iron content. CONCLUSIONS: Increased echogenicity of the SN, characteristically seen in Parkinson disease, is related to a functional impairment of the nigrostriatal system (even in young healthy adults) that can be revealed by [18F]-dopa PET studies. Substantia nigra hyperechogenicity is related to a higher tissue iron level, which is known to enhance the cells' generation of reactive oxygen specimens. Therefore, we hypothesize that transcranial sonography may identify a susceptibility marker for the development of nigral injury that can be detected early in life, prior to the onset of Parkinson disease.

Adolescent↗

PubMed2002

Camptocormia in Parkinson's disease mimicked by focal myositis of the paraspinal muscles.

We report on a 63-year-old man with idiopathic Parkinson's disease who developed kyphosis and a severe forward flexion of the thoracolumbar spine. A typical feature was an increase during walking or standing and it completely disappeared in the supine position, mimicking the clinical phenomenon of camptocormia (bent spine). In addition to the abnormal posture, a weakness of the erector spinal muscles, local pain, reddening, and elevated temperature of the paraspinal muscles were evident. Creatine kinase was initially elevated, electromyography showed spontaneous activity and a myopathic pattern. Magnetic resonance imaging and bioptic examinations revealed a focal myositis of the paraspinal muscles. This case indicates that camptocormia can be mimicked by focal myositis of paraspinal muscles and must be included in the differential diagnosis, especially when additional symptoms as inflammatory signs or weakness are present.

Anti-Inflammatory Agents↗

PubMed2002

Evidence for shoulder girdle dystonia in selected patients with cervical disc prolapse.

Some patients with cervical disc herniation suffer from persistent nuchal pain and muscle spasms after decompressive surgery despite the lack of clinical and radiological signs for actual spinal root compression. Sonographic examination of the brain in some of these patients showed increased echogenicity of the lentiform nuclei as described in patients with idiopathic dystonia. This has been linked to an altered Menkes protein level and copper metabolism. We suggest a relationship between persistent nuchal pain after adequate cervical disc surgery and dystonic movement disorders. Thirteen patients with persistent nonradicular nuchal pain after at least one cervical disc surgery and without evidence of continuing spinal root compression and 13 age-matched controls were included. All patients had a complete neurological examination, ultrasound, and MRI scan of the brain. In addition, Menkes protein mRNA levels of leucocytes were analyzed in patients and controls. All patients with persistent nuchal pain exhibited a constant tonic unilateral shoulder elevation associated with an ipsilateral hypertrophy of the trapezius muscle. Ultrasound examination showed an increased echogenicity of the lentiform nucleus in one patient unilaterally and in 10 patients bilaterally but in none of the controls. On MRI the T2-values of the lentiform nuclei were found to be higher in patients exhibiting a hyperechogenicity of the lentiform nuclei compared to controls (P = 0.01). In addition, Menkes protein mRNA levels were decreased in patients with cervical disc herniation (P = 0.03). Clinical, neuroimaging, and biochemical findings of this selected patient sample with chronic nuchal pain and muscle spasms after cervical disc surgery resemble alterations in patients with idiopathic cervical dystonia. This suggests a link between both disorders. A peripheral trauma to the nerve roots may precipitate dystonic movements in susceptible patients and chronic dystonic muscle contraction would account for the persistent nuchal pain.

Adenosine Triphosphatases↗

PubMed2002

Perspectives of B-mode transcranial ultrasound.

Transcranial color coded sonography has proved valuable in the diagnostic work-up of cerebrovascular disorders in adults. More recently, evidences have converged that transcranial sonography is also useful in the diagnosis of brain parenchymal disorders. Here, a new field of application is the visualization of signal intensity shift in specific brain areas in some neurodegenerative disorders (Parkinson's disease, idiopathic dystonia, and depression). Findings obtained by transcranial ultrasound complement information from other neuroimaging data in these disorders and have led to the generation of new pathophysiological concepts. In this review we summarize the application fields of transcranial sonography with special emphasis on recent findings in neurodegenerative disorders and their implications for future research. As new application and processing techniques are being developed transcranial color coded sonography will gain increasing impact on both diagnosis and research of neurological disorders.

Adult↗

PubMed2002

Early diagnosis of Parkinson's disease.

In idiopathic Parkinson's disease (IPD) approximately 60 % of the nigrostriatal neurons of the substantia nigra (SN) are degenerated before neurologists can establish the diagnosis according to the widely accepted clinical diagnostic criteria. It is conceivable that neuroprotective therapy starting at such an 'advanced stage' of the disease will fail to stop the degenerative process. Therefore, the identification of patients at risk and at earlier stages of the disease appears to be essential for any successful neuroprotection. The discovery of several genetic mutations associated with IPD raises the possibility that these, or other biomarkers, of the disease may help to identify persons at risk of IPD. Transcranial ultrasound have shown susceptibility factors for IPD related to an increased iron load of the substantia nigra. In the early clinical phase, a number of motor and particularly non-motor signs emerge, which can be identified by the patients and physicians years before the diagnosis is made, notably olfactory dysfunction, depression, or 'soft' motor signs such as changes in handwriting, speech or reduced ambulatory arm motion. These signs of the early, prediagnostic phase of IPD can be detected by inexpensive and easy-to-administer tests. As one single instrument will not be sensitive enough, a battery of tests has to be composed measuring independent parameters of the incipient disease. Subjects with abnormal findings in this test battery should than be submitted to nuclear medicine examinations to quantify the extent of dopaminergic injury and to reach the goal of a reliable, early diagnosis.

3-Iodobenzylguanidine↗

PubMedDate not supplied

Prognostic and diagnostic value of global cerebral blood flow volume and cerebral transit time in acute stroke.

Conventional duplex sonography is a well-established method for the assessment of the brain-supplying arteries in acute stroke. However, ultrasound (US) remains inconclusive in a significant number of stroke patients. Recently, two new US parameters, the cerebral transit time (cTT) and the global cerebral blood flow volume (CBF), have been introduced. In the present study, we investigated the diagnostic and prognostic value of both parameters in stroke patients. Conventional duplex examinations of the extra- and intracranial brain-supplying arteries and measurement of cTT and CBF were performed in 50 consecutive stroke patients within 24 h after symptom onset and compared with US findings in 22 age-matched healthy controls. Neurological deficits and the degree of disability were graded using several stroke scores, and were re-evaluated for outcome measure after 1 year. CBF and cTT were not assessable in 26% and 20% of the patients, respectively. Compared with the healthy control group, stroke patients showed a significant reduction of CBF and prolongation of cTT. More than 50% of patients with otherwise normal routine duplex examination had abnormal CBF or cTT findings. Furthermore, there was a strong correlation between the reduction of global CBF and the outcome after 1 year. Sonographic assessment of the CBF and cTT are additional parameters that might increase the diagnostic sensitivity of US in stroke patients, and may have prognostic relevance.

Acute Disease↗