Clinical and electromyographic examinations of patients with tremor after chronic occupational lead exposure

Tremor is considered to be a clinical sign of patients with chronic lead exposure. However, the type of tremor and its pathophysiological mechanisms are controversial. The aim of this study was to examine the clinical and electromyographic characteristics of tremor in patients with chronic lead exposure. Twenty-three men, 27-49 years old, participated in the study. The tremor activity was detected using surface electrodes from a pair of antagonistic hand muscles. Serum lead concentrations were measured on the day of examination. Our results revealed 12 Hz postural and kinetic tremor, with characteristics of enhanced physiological tremor. Different pathophysiological mechanisms might be responsible for the enhanced physiological tremor of patients with chronic lead exposure. In conclusion, the tremor of patients with chronic lead exposure is an enhanced physiological one. It is probable that this tremor could be influenced by beta-blockers, known to influence the enhanced physiological tremor in anxiety. This will be of benefit for patients disturbed by persistent tremor.     

Central nervous system impairment in diabetic patients

The aims of this study were to investigate the function of the central motor control system in interaction with the vestibular and auditory systems (measured by H-reflex changes in response to vestibular and acoustic stimulations) in diabetics without clinical data for CNS impairment, in order to establish whether the disease affects these CNS mechanisms; and to assess this approach in detecting subclinical CNS diabetic pathology. The results show the same mode of change of H-reflex amplitude in response to acoustic and vestibular stimulations in diabetics as in normal subjects. However the degree of facilitation and inhibition was significantly (p < 0.001) higher in diabetics which indicates subclinical CNS dysfunction. Therefore it was concluded that the test is useful in early diagnosis of the diabetic CNS impairment.     

Constitutional trisomy 8 mosaicism due to meiosis II non-disjunction in a phenotypically normal woman with hematologic abnormalities

Constitutional trisomy 8 mosaicism (CT8M) in liveborns is typically caused by mitotic non-disjunction and exhibits wide phenotypic variability. By contrast, CT8M due to meiotic errors usually results in miscarriage. We describe a case of CT8M due to a paternal meiosis II non-disjunction error. The patient, a 32-year-old woman, was phenotypically normal except for a history of recurrent aphthous ulcers since childhood and a 4-year history of macrocytosis. The ulcers were refractory to steroids, but responded well to thalidomide. To the best of our knowledge, this is the first report of CT8M due to meiotic non-disjunction in a phenotypically normal individual.     

Determination of phenacetin and salophen analgetics in solid binary mixtures with caffeine by infrared linear dichroic and Raman spectroscopy

Quantitative infrared (IR) and Raman spectroscopic approach for determination of phenacetin (Phen) and salophen (Salo) in binary solid mixtures with caffeine: phenacetin/caffeine (System 1) and salophen/caffeine (System 2) is presented. Absorbance ratios of 746 cm(-1) or 721 cm(-1) peaks (characteristic for each of determined compounds in the Systems 1 and 2) to 1509 cm(-1) and 1616 cm(-1) (attributed to Phen and Salo, respectively) were used. The IR spectroscopy gives confidence of 98.9% (System 1) and 98.3% (System 2), while the Raman spectroscopic data are with slightly higher confidence of 99.1% for both systems. The limits of detection for the compounds studied were 0.013 and 0.012 mole fraction for IR and Raman methods, respectively. Solid-state linear dichroic infrared (IR-LD) spectral analysis of solid mixtures was carried out with a view to obtaining experimental IR spectroscopic assignment of the characteristic IR bands of both determined compounds. The orientation technique as a nematic liquid crystal suspension was used, combined with the so-called reducing-difference procedure for polarized spectra interpretation. The possibility for obtaining supramolecular stereo structural information for Phen and Salo by comparing spectroscopic and crystallographic data has also been shown. An independent high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) analysis was performed for comparison and validation of vibrational spectroscopy data. Applications to 10 tablets of commercial products APC and Sedalgin are given.     

Increased alpha (8-12 Hz) activity during slow wave sleep as a marker for the transition from implicit knowledge to explicit insight

The number reduction task (NRT) allows us to study the transition from implicit knowledge of hidden task regularities to explicit insight into these regularities. To identify sleep-associated neurophysiological indicators of this restructuring of knowledge representations, we measured frequency-specific power of EEG while participants slept during the night between two sessions of the NRT. Alpha (8-12 Hz) EEG power during slow wave sleep (SWS) emerged as a specific marker of the transformation of presleep implicit knowledge to postsleep explicit knowledge (ExK). Beta power during SWS was increased whenever ExK was attained after sleep, irrespective of presleep knowledge. No such EEG predictors of insight were found during Sleep Stage 2 and rapid eye movement sleep. These results support the view that it is neuronal memory reprocessing during sleep, in particular during SWS, that lays the foundations for restructuring those task-related representations in the brain that are necessary for promoting the gain of ExK.     

Clinical and electrophysiological characteristics of neuropathy associated with Tangier disease

Tangier disease (TD) (OMIM#205400) is a rare autosomal recessive disorder resulting from mutations in the ABCA1 gene, leading to decreased levels of plasma high-density lipoproteins (HDL). Peripheral neuropathy is a common finding in this disease, and may present as relapsing/remitting mono/polyneuropathies or as syringomyelia-like neuropathy. We retrospectively analyzed four patients, and report here their clinical, biological, electrophysiological, imaging, and genetic findings. Three patients had a typical pseudosyringomyelic neuropathy including facial diplegia, but asymmetrical onset was observed in one patient who had first been misdiagnosed with Lewis-Sumner syndrome. Electrophysiological pattern was heterogeneous, showing both signs of demyelination and axonal degeneration. Truncating mutations of the ABCA1 gene, including two previously undescribed mutations, were constantly found. Atypical symptom onset and demyelinating features on electrophysiological examination can be misleading in case of pseudosyringomyelic neuropathy. These reports illustrate two different neurological phenotypes in TD, namely the pseudosyringomyelic type and the Lewis-Sumner-like type, and advocate for a systematic assessment of lipid profile including HDL cholesterol in demyelinating neuropathies.