n-Hexane and its metabolites are neurotoxic to animals and man. Studies have revealed a progressive neuropathy which affects the distal regions of motor and sensory peripheral nerves. This paper describes efforts to determine whether 2-hexanone or 2,5-hexanedione is more neurotoxic to rats when given in drinking water. Our results show that 2,5-hexanedione is more neurotoxic than 2-hexanone and that it first affects the distal axon. Concentrations of 20 mM produced no effects after 3 weeks but 40 mM increased distal latency after 2 weeks.

Introduktion: Vid perifera nervundersökningar med elektroneurografi spelar temperaturen i vävnaden som undersöks stor roll. Kall vävnad leder till försämrad funktion i nervernas jonkanaler, vilket leder till att aktionspotentialer utlöses långsammare och nervledningshastigheten minskar vilket därmed kan ge falskt patologiska undersökningsresultat. För att minska den risken mäts och korrigeras alltid hudtemperaturen. Vid registrering från övre extremiteter mäts hudtemperaturen standardmässigt på handryggen. Trots att stimulering sker från handflatan och från fingrar så mäts inte temperaturen där. Syftet med studien är därför att undersöka om kalla fingrar på en i övrigt varm hand påverkar conduction velocity och peaklatenstiden, jämfört med när hand och fingrar har samma varma temperatur. Metod: 30 unga, friska personer deltog i studien. Ortodrom elektroneurografiundersökning utfördes på nervus medianus sensoriska del. Handryggstemperaturen var konstant 32° Celsius (C) och fingertoppstemperaturerna var 32° C, 27° C respektive 22° C. Vid varje fingertoppstemperatur registrerades conduction velocity och peaklatenstiden vid stimuleringar från handflatan, fingerbasen och fingertoppen på digitorum III. Resultat: En statistiskt signifikant skillnad fanns i både nervledningshastigheten och peaklatenstiden vid registrering från fingerbasen vid fingertoppstemperaturen 32° C jämfört med såväl 27° C som 22° C. Slutsats: Kalla fingrar på en varm hand ger en statistiskt signifikant påverkan på både nervledningshastigheten och peaklatenstiden. / Background: In peripheral nerve examinations with electroneurography, temperatures in the tissue that is being examined is important. Cold tissue leads to impaired function of the ion channels of the nerves, which causes action potentials to be triggered more slowly and the nerve conduction velocity to decrease, which can cause false pathological examination results. To reduce this risk, the skin temperature is always measured and corrected. When registering from the upper extremities, the skin temperature is measured by default on the back of the hand. Despite stimulating in the palm and on the fingers, the temperature is not measured there. The purpose of the study is to investigate whether cold fingers on a warm hand affects the conduction velocity and peak latency time, compared with the hand and the fingers having the same warm temperature. Methods: 30 young, healthy persons participated in the study. An orthodrome electroneurography examination was performed on the sensory part of the median nerve. The backhand temperature was constant 32° Celsius (C) and the fingertip temperatures were 32 ° C, 27 ° C and 22 ° C. Results: A statistically significant difference was found in both nerve conduction velocity and peak latency time when registering from the finger base with fingertip temperature 32 ° C compared with both 27 ° C and 22 ° C Conclusions: Cold fingers on a warm hand give a statistically significant effect on both the nerve conduction velocity and the peak latency time.

Smelter workers who were exposed to air-borne arsenic for a mean of 23 years, and age-matched referents, were examined with clinical, physiological, and neurophysiological methods. Exposure to arsenic in workroom air was estimated to have been around the Swedish occupational limits, which were 500 yg/m before 1975 and 50 yg/ra thereafter. An increased preval ence of Raynaud's phenomenon and a reduced finger systolic blood pressure (FSP) during local and general cooling were found in the smelter workers. Slight, but significant sub-clinical neuropathy, in the form of slightly reduced nerve conduction velocity (NCV) in two or more peripheral nerves, was more common among the arsenic workers than among the referents. There were positive correlations between cumulative exposure to arsenic, reduced NCV in three peripheral motor nerves, and decrease in FSP during cooling. Arsenic levels in urine were 1 ymole/1 (75 yg/1) in the arsenic workers and 0.1 ymole/1 in the referents. In 21 arsenic workers with no or very low exposure to vibra ting hand tools, the FSP during cooling had increased significantly after 3 years wit h the lower arsenic exposure. There was no change in FSP during the summer vacation, whereas urinary levels of arsenic decreased to normal values. Thus there seems to be a slow improvement of finger blood circ ulation which is independent of short-term fluctuations in the exposure to arsenic. No seasonal variation was found in FSP during cooling with the standardized method used. When the NCV-measurements were repeated five years later the difference between arsenic workers and referents had increased, despite the fact that 14 of the 47 arsenic workers had had no exposure to arsenic during the last 1-5 years. These observations indicate, that in subjects with long term exposure to arsenic, sub-clinical neuropathy is not reversible. Ten milligrams of Ketanserin, a serotonin receptor antagonist, was given intravenously to five arsenic workers with cold-induced vasospasm. Skin temperature and FSP during cooling increased significantly with Ketanserin as compared wit h saline solution. After oral treatment, 2 x 40 mg /day for four weeks, no significant increase of FSP during cooling or rise in skin temperature was found in six arsenic workers and eleven patients with Raynaud's phenomenon. The decrease of vasospastic tendency after intravenous injection of Ketanserin indicated that similar mechanisms might operate in arsenic-induced and other types of Raynaud's phenomenon. A general co nclusion from the five studies in this dissertation is that long-term occupational exposure to arsenic has had adverse effects on the peripheral circulation and nerve conduction. The tendency to vasospasm, but not the sub-clinical neuropathy, seemed to be reversible with decreasing exposure. / <p>S. 1-54: sammanfattning, s. 55-112: 5 uppsatser</p> / digitalisering@umu

Submitted by Nadir Basilio (nadirsb@uninove.br) on 2018-06-19T13:41:01Z No. of bitstreams: 1 Fabiana Sarilho de Mendonca.pdf: 960484 bytes, checksum: be95fe89cc95556dccc9a63e7868ac13 (MD5) / Made available in DSpace on 2018-06-19T13:41:01Z (GMT). No. of bitstreams: 1 Fabiana Sarilho de Mendonca.pdf: 960484 bytes, checksum: be95fe89cc95556dccc9a63e7868ac13 (MD5) Previous issue date: 2015-12-15 / Although the low level light therapy (LLLT) irradiation is indicated for a variety of musculoskeletal disorders like muscle fatigue, tissue repair and as anti-inflammatory agent, its effects on muscle activity are still poorly understood. The objective of this study was to evaluate the immediate effect of LLLT of irradiation on the nerve conduction velocity and electromyographic activity of the muscle upper trapezius (UT) in healthy subjects. Twenty healthy women (mean age 23.54  2.51) were included in this study, cross-over, controlled, randomized, double blind. Each volunteer has received two types of treatment with continuous LLLT (LLLT) and the other one with LLLT placebo (LLLTP). The treatment order was randomized by raffle, being included an interval of 7 days between each laser intervention (wash-out) to prevent residual effects. The surface electromyography (EMG) was used to verify the nerve conduction velocity (CV) and muscle activity UT during shoulder elevation in isometric contraction to 5 different levels of contraction (10, 15, 20, 25, 30% of maximum voluntary contraction), via visual feedback provided through a driving line. The collects of the EMG signal were performed before and after 30 minutes of treatment (LLLT or LLLTP). In the analysis of variance for repeated measures (ANOVA) it was possible to observe a significant decrease in the amplitude of the EMG signal to treatment with LLLT (p = 0.0001) but not to the placebo treated group (p < 0.05). Regarding of the CV, no change was observed for both treatments (LLLT: p > 0.05; LLLTP: p > 0.05 - ANOVA). In this study it could be observed an immediate effect of LLLT irradiation on the amplitude of the electromyographic signal of the trapezius muscle descending fibers in healthy individuals, but not on the nerve conduction velocity. / Embora a irradiação com laser de baixa potência (LBP) seja indicada para vários tipos de disfunções musculoesqueléticas como fadiga muscular, reparo tecidual e como agente anti-inflamatório, seus efeitos sobre a atividade muscular ainda são pouco conhecidos. O objetivo desse estudo foi avaliar o efeito imediato da irradiação do LBP sobre a velocidade de condução nervosa e a atividade eletromiográfica do músculo trapézio fibras descendentes (TFD) em indivíduos saudáveis. Vinte mulheres saudáveis (idade média: 23,54  2,51) foram incluídas nesse estudo, cruzado, controlado, randomizado duplo cego. Cada voluntária recebeu 2 tipos de tratamento com LBP (LBP) contínuo e outra com LBP placebo (LBPP). A ordem de tratamento foi randomizada por sorteio, sendo incluído um intervalo de 7 dias entre cada intervenção de laser (wash-out) para evitar efeitos residuais. A eletromiografia (EMG) de superfície foi utilizada para verificar a velocidade de condução nervosa (VC) e atividade no músculo TFD durante a elevação do ombro em contração isométrica em 5 diferentes níveis de contração (10, 15, 20, 25, 30% da contração voluntária máxima), por meio de feedback visual proporcionado por uma linha de treino. As coletas do sinal EMG foram realizadas antes e após 30 minutos do tratamento (LBP ou LBPP). Na análise de variância para medidas repetidas (ANOVA) foi possível observar diminuição significativa na amplitude do sinal EMG para o tratamento com LBP (p = 0,0001) porém não para o grupo tratado com LBPP (p < 0,05). Em relação à VC, nenhuma alteração foi observada para ambos os tratamentos (LBP: p > 0,05; LBPP: p > 0,05 - ANOVA). Nesse estudo foi possível observar um efeito imediato da irradiação com LBP sobre a amplitude do sinal eletromiográfico do músculo trapézio fibras descendentes em indivíduo saudáveis, porém, não sobre a velocidade de condução nervosa.

Introduktion: Elektroneurografi används för att bedöma nervfunktion och påvisa patologiska förändringar i det perifera nervsystemet. Det är en metod känslig för störningar och registreringarna kan påverkas av temperaturen i huden och underliggande vävnad, då värme ökar de perifera nervernas nervledningshastighet.   Fysisk aktivitet har bevisats ha positiva effekter på hälsan och involverar många av kroppens organsystem. En sådan effekt är en ökad metabolism i skelettmusklerna, vilket genererar värme.   Syfte och frågeställning: Syftet är att undersöka de perifera nerverna i en nedre extremitet hos en grupp neurologiskt friska individer utan diagnosticerad diabetes med elektroneurografi, för att se om fysisk aktivitet har någon effekt på den perifera nervfunktionen.   Metod och material: Tre perifera nerver i individernas (n=18) dominanta ben; nervus (n) suralis, n. peroneus och n. tibialis undersöktes med elektroneurografi före och efter måttlig fysisk aktivitet. N. suralis undersöktes sensoriskt och n. peroneus och n. tibialis undersöktes motoriskt och F-respons registrerades. Hudtemperatur och kroppstemperatur mättes inför samtliga registreringar och ansträngningsgrad vid den fysiska aktiviteten uppskattades.   Resultat: Signifikant skillnad mellan registreringarna från n. suralis kunde ses vad gäller latenstid och ledningshastighet, och den distala amplituden, proximala latenstiden samt ledningshastigheten för n. peroneus. Dessutom kunde signifikant skillnad ses i den proximala latenstiden för n. tibialis, och i F-M-latenstiden för n. peroneus och n. tibialis.   Slutsats: En positiv effekt kan ses i en del variabler, troligtvis beroende på temperaturskillnaderna mellan registreringarna. Dock skulle en större undersökningsgrupp potentiellt ge tydligare resultat. / Introduction: Electroneurography is used to assess nerve function and detect pathological changes in the peripheral nerve system. The method is sensitive to interference and measurements can be affected by temperature of the skin and underlying tissue, because heat increases nerve conduction velocity of the peripheral nerves.   It has been concluded that physical activity have a positive effect on health and involves many of the body´s organsystems. One of these effects is an increase in metabolism in skeletal muscles, which generates heat.   Purpose: The purpose is to examine the peripheral nerves in a lower extremity in a group of neurologically healthy individuals without diagnosed diabetes with electroneurography, to determine if physical activity has any effect on the peripheral nerve function.   Method and material: Three peripheral nerves in the individuals (n=18) dominant leg; nervus (n) suralis, n. peroneus and n. tibialis, were examined with electroneurography before and after moderate physical activity. N. suralis were examined for sensory function and n. peroneus and n. tibialis were examined for motor function and F-response. Skin temperature and body temperature were measured before every registration and the individuals assessed their degree of physical effort.   Results: Significant diffrence between the registrations could be seen in the latency and conduction velocity for n. suralis, in the distal amplitude, proximal latency and conduction velocity for n. peroneus, in the proximal latency for n. tibialis and the F-M-latency for n. peroneus and n. tibialis.   Conclusion: A positive effect can be seen on some variables, probably because of temperature diffrences between the registrations. However a larger test group could potentially yield more distinct results.

Made available in DSpace on 2016-06-02T19:22:05Z (GMT). No. of bitstreams: 1 3198.pdf: 3159049 bytes, checksum: 5e8ac93b5a62ff5a959370c795dac4e9 (MD5) Previous issue date: 2010-09-03 / This thesis presents three manuscripts derived of two research projects that were developed during the doctorate program. Project 1. Purpose: To determine the interand intra-rater reliability of nerve conduction studies (NCS) of superficial peroneal, sural and medial plantar nerves. Methods: Two raters performed the bilateral NCS twice in 20 healthy participants (23.5±3.5 years). Reliability was analyzed by the Bland- Altman method and intraclass correlation coefficient (ICC). Results: The Bland-Altman method showed a good level of intra- and inter-rater agreement for all parameters nerves. The amplitude and latency of the medial plantar nerve (rater 1), as well the amplitude of the sural nerve (rater 2) had an intra-rater ICC &#8805;0.75. Inter-rater analysis showed concordance levels between moderate and very low. Project 2. Purposes: a) To compare the effects of three cold modalities on the nerve conduction parameters of the sural (sensory) and tibial (motor) nerves during cooling and post-cooling phases b) To analyze the effect of exercise on recovery of sensory and motor nerve conduction velocity (NCV). Methods: Thirty six healthy young subjects (20.5±1.9 years) were randomly allocated into three groups: ice massage (n=12), ice pack (n=12) and cold water immersion (n=12). Each group received 1 of the 3 cold modalities on the right calf region for 15 minutes. The subjects of each modality group were again randomized to perform a post-cooling activity (30 min rest or walk 15 min followed by rest 15min). Nerve conduction parameters of sural and posterior tibial nerves were evaluated. Results: All 3 modalities reduced amplitude and increased latency and duration of the compound action potential. Ice massage, ice pack, and cold water immersion reduced NCV by 20.4, 16.7, and 22.6 m/s and motor NCV by 2.5, 2.1, and 8.3 m/s, respectively. Cold water immersion, as applied in this study, was the most effective modality in changing nerve conduction parameters. The walk accelerated the recovery of sensory and motor NCV, regardless of the modality previously applied (p<0.0001). Conclusions: The NCS provides quantitative measures that contribute to the objective analysis of neural physiological effects of cryotherapy. All 3 modalities were effective in altering sensory and motor nerve conduction. However, the magnitude and duration of these effects depend on the method applied and the activity after cooling. / Esta tese apresenta três manuscritos derivados de dois projetos de pesquisa que foram desenvolvidos no doutorado. Projeto 1. Objetivo: Avaliar a confiabilidade intra e interavaliador dos testes de condução nervosa (TCN) nos nervos sural, peroneal superficial e plantar medial. Métodos: Dois examinadores realizaram duas vezes os TCN bilaterais em 20 participantes saudáveis (23,5±3,5 anos). A confiabilidade foi analisada pelo método de Bland-Altman e o coeficiente de correlação intraclasse (ICC). Resultados: O método de Bland-Altman indicou um bom nível de concordância intra e inter-avaliador para todos os parâmetros dos TCN. Foram observados ICC intra-avaliador &#8805; 0,75 para amplitude e latência do nervo plantar medial (avaliador 1) e para a amplitude do nervo sural (avaliador 2). A análise inter-avaliador mostrou níveis de concordância entre moderados e muito baixos. Projeto 2. Objetivos: a) Comparar os efeitos de três modalidades de crioterapia sobre os parâmetros de condução dos nervos tibial posterior (motor) e sural (sensorial) durante as fases de resfriamento e pós-resfriamento b) Analisar o efeito do exercício físico na recuperação da velocidade de condução nervosa (VCN) sensorial e motora. Métodos: Trinta e seis sujeitos jovens e saudáveis (20,5±1,9 anos) foram alocados aleatoriamente em três grupos: criomassagem (n=12), pacote de gelo (n=12); imersão em água gelada (n=12). Cada grupo recebeu uma das 3 modalidades de resfriamento na panturrilha direita, durante 15 min. Os sujeitos de cada grupo foram novamente aleatorizados para realizar uma atividade pós-resfriamento (30min de repouso ou 15min de marcha seguido de 15min de repouso). Avaliaram-se os parâmetros de condução nos TCN dos nervos sural e tibial posterior. Resultados. As três modalidades reduziram a amplitude e aumentaram a latência e duração do potencial de ação composto. Criomassagem, pacote de gelo e imersão em água gelada reduziram a VCN sensorial em 20,4, 16,7 e 22,6 m/s, e a VCN motora em apenas 2,5, 2,1 e 8,3 m/s, respectivamente. Imersão em água gelada, como usada neste estudo, foi a modalidade mais eficaz para alterar os parâmetros de condução nervosa. A marcha acelerou a recuperação da VCN sensorial e motora, independente da modalidade previamente aplicada (P<0,0001). Conclusões. Os TCN fornecem medidas quantitativas que subsidiam análises objetivas e úteis na avaliação dos efeitos fisiológicos neurais da crioterapia. As 3 modalidades de resfriamento foram eficazes para alterar a condução sensorial e motora. Contudo, a magnitude e duração desses efeitos dependem do tipo de modalidade usada e da atividade que se realiza após o resfriamento.

Peripheral neuropathies are a set of common diseases that affect the peripheral nervous system, causing damage to vital connections between various parts of the body and the brain and spinal cord. Different clinical conditions are known to selectively impact various size nerve fibers, which often makes it difficult to diagnose which peripheral neuropathy a patient might have. The nerve conduction velocity diagnostic test provides clinically useful information in the diagnosis of some peripheral neuropathies. This method is advantageous because it tends to be minimally invasive yet it provides valuable diagnostic information. However, this test does not determine characteristics of peripheral nerve fiber size distributions, and therefore does not show any detailed information regarding the nerve fibers within the nerve trunk. Being able to determine which nerve fibers are contributing to the evoked potential within a nerve trunk could provide additional information to clinicians for the diagnosis of specific pathologies of the peripheral nervous system, such as chronic inflammatory demyelinating polyneuropathy or early diabetic peripheral neuropathy. In this study, three rat sciatic nerves are sectioned and stained with hematoxylin and eosin in order to measure the nerve fiber diameters within the nerve trunk. Stained samples are viewed using brightfield microscopy and images are analyzed using ImageJ. Histograms were created to show the frequency of various nerve fiber diameters. The nerve fiber diameters measured during this research are consistent with the range of previously published diameter values and will be used to support continuing research for a novel method to characterize peripheral nerve fiber size distributions using group delay.

Diabetiker entwickeln nach durchschnittlich 10 Jahren Folgeschäden. Die Polyneuropathie mit nachfolgender Osteoarthropathie des Fußes ist eine meist zu spät erkannte und suboptimal versorgte Komplikation. Nicht rechtzeitig erkannte Schäden führen zu Ulcera, sekundären Infektionen, Osteomyelitiden und Amputationen. Fragestellung: Ist eine Ganganalyse incl. Posturographie in der Lage, eine evtl. bestehende Polyneuropathie zu verifizieren, um eine frühzeitige orthopädische Schuhversorgung vornehmen zu können? Material und Methoden: Es wurden Diabetiker (n = 73) mit (mittels Messung der Nervenleitgeschwindigkeit NLG) nachgewiesener Neuropathie und eine gesunde Vergleichsgruppe (n = 38) ohne Neuropathie am Ganganalysesystem GANGAS untersucht. Ergebnisse: Die Allgemeinparameter relative Geschwindigkeit, Schrittlänge und Kadenz, sowie die Belastungsparameter Fersen-, Mittelfuß-, Vorfußbelastung und Belastung beim Auftritt und Abstoß zeigten keine wesentlich signifikanten Unterschiede im Gruppenvergleich. Dagegen zeigte die Posturographie (apparative Untersuchung der Schwankung des Druckschwerpunktes beim Romberg-Test, welche durch die Länge und Geschwindigkeit beschrieben wurde) signifikante Unterschiede zwischen beiden Patientengruppen. So lag z.B. der Median der Weglänge des Druckschwerpunktes beim Test mit geschlossenen Augen bei den Diabetikern bei 21,27 cm und in der Vergleichsgruppe bei 15,4 cm (p = 0,007). Die Bewegungsgeschwindigkeit des Druckschwerpunktes beim Test mit geschlossenen Augen betrug im Median 1,33 cm/sec bei den Diabetikern und 0,96 cm/sec in der gesunden Vergleichsgruppe (p = 0,006). Beim Test mit offenen Augen ergab sich kein signifikanter Unterschied im Gruppenvergleich. Klinische Relevanz: Eine Instabilität des Ganges der Patienten mit diabetischer Neuropathie und entsprechenden Folgeschäden des Fußes läßt sich durch die Ganganalyse mit Standardparametern nach vorliegendem Datenmaterial nicht nachweisen. Die Posturographie ist eine einfache, zeitlich mit geringem Aufwand verbundene Methode, die mit statistischer Signifikanz die subjektiven Kriterien der klinisch-orthopädischen Frühdiagnostik sinnvoll ergänzen und damit die Verdachtsdiagnose eine diabetischen Fußes objektiv nachweisen kann, bevor bleibende Schäden am Fuß entstanden sind. / Every diabetic patient after about ten years develops secondary changes in different tissues. Polyneuropathy with consecutive osteoarthropathy of the foot often is recognized too late and suboptimal treated. Diabetic disorders recognized too late may lead to ulcera, secondery infections and even amputations. Question: Is standard gait analysis including posturography able to verify diabetic neuropathy in order to supply the patient with adapted orthopadic shoeware in time? Materials and methods: A group of diabetics (n=73) with proved neuropathy by measuring nerve conduction velocity and a healthy control group (n=38) without neuropathy were examined by the gait-analysis-system GANGAS. Results: The general parameters: relative speed, length of step and cadence as well as the loading parameters of the heel, middle foot and forefoot during treading and repulsion show no significant differences between both groups. Posturography however (apparative examination of the elongation of focal point of pressure (FPP) according to the Romberg test, described by length and speed) shows significant differences between both groups. For diabetics making the test with closed eyes the mean value of walking length of the FPP was 21,27 cm, for the healthy control persons it was only 15,4 cm (p = 0,007). Asimulary results were found for the speed of movement of FPP during the test with closed eyes: mean value in diabetics 1,33 cm/s and for the healthy control persons 0,96 cm/s (p = 0,006). During this test with open eyes there was no significant difference between both groups. Clinical Relevance: Walking instability of patients with diabetic neuropathy and corresponding sequential damage of the foot could not be proved by the current data with standard parameters. Posturography however is able to give additional information with statistical significance to the subjective criteria of the clinical-orthopedic early diagnosis and verify the diagnosis of a beginning diabetic foot before severe disorders have occured.