Mutations in HINT1 are one of the most frequent causes of hereditary neuropathy among Czech patients and neuromyotonia is rather an underdiagnosed symptom.

Mutations in the HINT1 gene were recently discovered as being the major cause of autosomal recessive axonal neuropathy with neuromyotonia. This combination was clinically recognized and described previously in a few reports but is generally unknown. We aimed to establish the importance of HINT1 mutations as the cause of hereditary neuropathy and particularly hereditary motor neuropathy/axonal Charcot-Marie-Tooth (HMN/CMT2) among Czech patients. Overall, mutations in the HINT1 gene seem to be a surprisingly frequent cause of inherited neuropathy in our group of patients. Biallelic pathogenic mutations were found in 21 patients from 19 families. The prevalent mutation in the Czech population is the p.R37P (95% of pathogenic alleles). Clinically, all patients with biallelic mutations presented with early onset of symptoms at the end of the first decade. Foot/toe extension weakness to plegia was present in almost all patients. Neuromyotonia was present in all but two patients. However, it had been properly recognized in only three patients prior to molecular genetic diagnosis. HINT1 mutations seem to be one of the most frequent causes of inherited neuropathy and are probably the most frequent cause of HMN in Czech patients. We suggest all HMN/CMT2 patients be tested for the presence of the prevalent mutation, the p.R37P.

Transient ischemic attack in the vertebro-basilar circulation due to a hemodynamically significant variation - kinking of the extracranial section of the left vertebral artery.

We present a case report of a 74-year old female patient with the clinical diagnosis of transient ischemic attack (TIA) in the vertebro-basilar (VB) circulation, in whom we found bilateral variation of the extracranial section of vertebral arteries on ultrasound, on the left side to the extent of kinking. This finding was later confirmed by magnetic resonance angiography (MRA). We discuss the presumed hemodynamic significance of this variation and its etiological relation to the patient's clinical picture. Ultrasound examination of the carotid and vertebro-basilar circulations is an important examination technique contributing to an early detection of possible aetiology of the cerebral circulation disorders (Fig. 7, Ref. 18).

Pycnogenol efficiency on glycaemia, motor nerve conduction velocity and markers of oxidative stress in mild type diabetes in rats.

The aim of this study was to describe the effects of Pycnogenol at various doses on preprandial and postprandial glucose levels, the levels of thiobarbituric acid reactive substances (TBARs) and N-acetyl-beta-d-glucosaminidase (NAGA) and on motor nerve conduction velocity (MNCV) in streptozotocin (STZ)-induced diabetic rats. Pycnogenol treatment (10, 20, 50 mg/kg body weight (b.w.)/day) lasted for 8 weeks after induction of diabetes. Pycnogenol significantly decreased elevated levels of preprandial glycaemia in treated animals at all doses. At doses of 10 mg/kg b.w./day and 20 mg/kg b.w./day it significantly decreased elevated levels of postprandial glycaemia compared with diabetic non-treated animals. Pycnogenol failed to induce a significant decrease of postprandial glycaemia at a dose of 50 mg/kg b.w./day. Pycnogenol improved significantly the impaired MNCV at doses of 10 and 20 mg/kg b.w./day compared with non-treated animals. The levels of TBARs were elevated in diabetic rats. The levels of NAGA increased gradually despite the treatment. Pycnogenol failed to affect the increased levels of TBARs and NAGA. Pycnogenollowered the elevated levels of glycaemia and reduced the decline in motor nerve conduction velocity in STZ-induced diabetic rats. The effect of Pycnogenol on postprandial glycaemic levels and MNCV was not dose-dependent.

Chronic toxic neuropathy after organophosphorus poisoning in quails (Coturnix coturnix japponica).

Peripheral neuropathy was induced by the long-term administration of organo-phosphorus compounds (phtalimid/phosmet) in quails (Coturnix coturnix japponica). After 4 weeks, the first symptoms of organophosphorus (OPC) poisoning (apathy, diarrhea) were present. During the second month of a daily administration of the toxic substance using the probe, an apparent clinical autonomic and peripheral neuropathy with ataxia had developed. Toxic disturbance of the nervous system was confirmed by the examination of spinal and cortical somatosensory evoked potentials (SEP) after tibial nerve stimulation. The prolongation of the peripheral conduction time (wave P6 and N9 represent the response from the ischiadic nerve and the entry of the stimulus to spinal cord, respectively) confirmed a peripheral nerve lesion. We suggest that these clinical and electrophysiological changes, displayed by the disturbed nervous system, are caused by either slowing or stoppage of the axonal flow, transport of proteins and other substances, as well as by axon demyelination (Tab. 1, Fig. 1, Ref. 22).

Sympathetic skin response: review of the method and its clinical use.

Sympathetic skin response (SSR) represents a potential generated in skin sweat glands; it originates by activation of the reflex arch with different kinds of stimuli. The potential of rapid habituation after repeated stimuli is formed by biphasic or triphasic slow wave activity with relatively stable latency and variable amplitude. In healthy subjects younger than 60 years of age the response is always present in all extremities. SSR is most frequently used in diagnosing the functional impairment of non-myelinated postganglionic sudomotor sympathetic fibers in peripheral neuropathies. In this study a more complex and informative view on the anatomical and physiological substrates of SSR, its character, normal values and technique are presented, focusing on problems in evaluation of the response and factors that have influence on it. Based on personal experience normative latency and amplitude values of SSR in a group of 20 healthy individuals (x +/- SD), upper extremities: 1.48 +/- 0.80 sec., 444 +/- 167 microV, respectively; lower extremities: 2.06 +/- 0.93 sec., 203 +/- 87.4 microV, respectively) and recommendations for qualitative evaluation preference--the presence or absence of the response--over quantitative evaluation of latency and amplitude of the response in practical clinical use of the method are presented. (Tab. 1, Fig. 2, Ref. 148.).

Clinically unapparent central motor pathways lesion in patients with type I diabetes mellitus. A transcranial magnetic stimulation study.

OBJECTIVE: There is an evidence of central nervous system (CNS) involvement in diabetic patients. The aim of the study was to determine a conduction slowing in CNS pathways using a transcranial magnetic stimulation (TMS) and F-wave latency measurement. METHODS: Diabetic patients and a control group, both without clinical symptoms and signs of CNS lesion were evaluated. Motor evoked potentials were recorded from upper and lower extremities and central conduction time (CCT) was calculated according to formula: CCT = MEP-[0.5x(F-M-1)+M]. Obtained results and data from literature were compared. RESULTS: There was a significant prolongation of CCT recorded from lower extremities. The prolongation of CCT recorded from upper extremities was not statistically significant. Our results correlate with previously published data. CONCLUSION: In spite of missing clinical signs of CNS lesion in diabetic patients, a significant prolongation of CCT compared to control group and literature data was recorded. We assume a presence of diffuse subclinical CNS lesion induced by metabolic changes in DM. Difference between CCT obtained from upper and lower extremities implicate, that changes are analogical to peripheral neuropathies ("central length-dependent injury?"). Measurement of CCT using TMS could become a complementary electrophysiological method for assessment of subclinical CNS involvement in diabetic patients. (Tab. 4, Ref. 17.)

Autonomic nervous system dysfunction in multiple sclerosis patients.

We present the results of our study dealing with autonomic nervous system (ANS) function in multiple sclerosis (MS) patients. We performed a cardiovascular reflex examination (heart rate variation in deep breathing and active standing) and spectral analysis of heart rate variability in 36 MS patients who fulfilled the criteria for this diagnosis. We evaluated several various indexes used for the assessment of ANS function: I/E, I-E in deep breathing test; RRmax/RRmin in active standing, spectral analysis of heart rate variability in VLF, LF and HF bands were performed. We found a significant difference in I-E index values during deep breathing test in MS patients when compared to the healthy control group; we did not find any difference in I/E index (deep breathing test) and RRmax/RRmin (active standing) values. The spectral analysis of heart rate variability in the rest-tilt-rest test showed a significant difference in spectral powers in MS patients when compared to the healthy control group in all frequency bands. (Tab. 2, Fig. 7, Ref 17.)