Importing genetically altered animals: ensuring quality.

The reproducibility of research using laboratory animals requires reliable management of their quality, in particular of their genetics, health and environment, all of which contribute to their phenotypes. The point at which these biological materials are transferred between researchers is particularly sensitive, as it may result in a loss of integrity of the animals and/or their documentation. Here, we describe the various aspects of laboratory animal quality that should be confirmed when sharing rodent research models. We also discuss how repositories of biological materials support the scientific community to ensure the continuity of the quality of laboratory animals. Both the concept of quality and the role of repositories themselves extend to all exchanges of biological materials and all networks that support the sharing of these reagents.

A paternal methyl donor-rich diet altered cognitive and neural functions in offspring mice.

Dietary intake of methyl donors, such as folic acid and methionine, shows considerable intra-individual variation in human populations. While it is recognized that maternal departures from the optimum of dietary methyl donor intake can increase the risk for mental health issues and neurological disorders in offspring, it has not been explored whether paternal dietary methyl donor intake influences behavioral and cognitive functions in the next generation. Here, we report that elevated paternal dietary methyl donor intake in a mouse model, transiently applied prior to mating, resulted in offspring animals (methyl donor-rich diet (MD) F1 mice) with deficits in hippocampus-dependent learning and memory, impaired hippocampal synaptic plasticity and reduced hippocampal theta oscillations. Gene expression analyses revealed altered expression of the methionine adenosyltransferase Mat2a and BK channel subunit Kcnmb2, which was associated with changes in Kcnmb2 promoter methylation in MD F1 mice. Hippocampal overexpression of Kcnmb2 in MD F1 mice ameliorated altered spatial learning and memory, supporting a role of this BK channel subunit in the MD F1 behavioral phenotype. Behavioral and gene expression changes did not extend into the F2 offspring generation. Together, our data indicate that paternal dietary factors influence cognitive and neural functions in the offspring generation.

Peri-conceptional obesogenic exposure induces sex-specific programming of disease susceptibilities in adult mouse offspring.

Vulnerability of the fetus upon maternal obesity can potentially occur during all developmental phases. We aimed at elaborating longer-term health outcomes of fetal overnutrition during the earliest stages of development. We utilized Naval Medical Research Institute (NMRI) mice to induce pre-conceptional and gestational obesity and followed offspring outcomes in the absence of any postnatal obesogenic influences. Male adult offspring developed overweight, insulin resistance, hyperleptinemia, hyperuricemia and hepatic steatosis; all these features were not observed in females. Instead, they showed impaired fasting glucose and a reduced fat mass and adipocyte size. Influences of the interaction of maternal diet∗sex concerned offspring genes involved in fatty liver disease, lipid droplet size regulation and fat mass expansion. These data suggest that a peri-conceptional obesogenic exposure is sufficient to shape offspring gene expression patterns and health outcomes in a sex- and organ-specific manner, indicating varying developmental vulnerabilities between sexes towards metabolic disease in response to maternal overnutrition.

Generation of mice lacking DUF1220 protein domains: effects on fecundity and hyperactivity.

Sequences encoding DUF1220 protein domains show the most extreme human lineage-specific copy number increase of any coding region in the genome and have been linked to human brain evolution. In addition, DUF1220 copy number (dosage) has been implicated in influencing brain size within the human species, both in normal populations and in individuals associated with brain size pathologies (1q21-associated microcephaly and macrocephaly). More recently, increasing dosage of a subtype of DUF1220 has been linked with increasing severity of the primary symptoms of autism. Despite these intriguing associations, a function for these domains has not been described. As a first step in addressing this question, we have developed the first transgenic model of DUF1220 function by removing the single DUF1220 domain (the ancestral form) encoded in the mouse genome. In a hypothesis generating exercise, these mice were evaluated by 197 different phenotype measurements. While resulting DUF1220-minus (KO) mice show no obvious anatomical peculiarities, they exhibit a significantly reduced fecundity (χ(2) = 19.1, df = 2, p = 7.0 × 10(-5)). Further extensive phenotypic analyses suggest hyperactivity (p < 0.05) of DUF1220 mice and changes in gene expression levels of brain associated with distinct neurological functions and disease. Other changes that met statistical significance include an increase in plasma glucose concentration (as measured by area under the curve, AUC 0-30 and AUC 30-120) in male mutants, fasting glucose levels, reduce sodium levels in male mutants, increased levels of the liver functional indicator ALAT/GPT in males, levels of alkaline phosphatase (also an indicator of liver function), mean R and SR amplitude by electrocardiography, elevated IgG3 levels, a reduced ratio of CD4:CD8 cells, and a reduced frequency of T cells; though it should be noted that many of these differences are quite small and require further examination. The linking of DUF1220 loss to a hyperactive phenotype is consistent with separate findings in which DUF1220 over expression results in a down-regulation of mitochondrial function, and potentially suggests a role in developmental metabolism. Finally, the substantially reduced fecundity we observe associated with KO mice argues that the ancestral DUF1220 domain provides an important biological functionthat is critical to survivability and reproductive success.

Characterization of the melanocortin-4-receptor nonsense mutation W16X in vitro and in vivo.

Several genetic diseases are triggered by nonsense mutations leading to the formation of truncated and defective proteins. Aminoglycosides have the capability to mediate a bypass of stop mutations during translation thus resulting in a rescue of protein expression. So far no attention has been directed to obesity-associated stop mutations as targets for nonsense suppression. Herein, we focus on the characterization of the melanocortin-4-receptor (MC4R) nonsense allele W16X identified in obese subjects. Cell culture assays revealed a loss-of-function of Mc4r(X16) characterized by impaired surface expression and defect signaling. The aminoglycoside G-418 restored Mc4r(X16) function in vitro demonstrating that Mc4r(X16) is susceptible to nonsense suppression. For the evaluation of nonsense suppression in vivo, we generated a Mc4r(X16) knock-in mouse line by gene targeting. Mc4r(X16) knock-in mice developed hyperphagia, impaired glucose tolerance, severe obesity and an increased body length demonstrating that this new mouse model resembles typical characteristics of Mc4r deficiency. In a first therapeutic trial, the aminoglycosides gentamicin and amikacin induced no amelioration of obesity. Further experiments with Mc4r(X16) knock-in mice will be instrumental to establish nonsense suppression for Mc4r as an obesity-associated target gene expressed in the central nervous system.

Inflammation and mitochondrial fatty acid beta-oxidation link obesity to early tumor promotion.

Obesity is associated with increased risk for developing pancreatic cancer, and it is suggested that insulin resistance provides the missing link. Here we demonstrate that under the context of genetic susceptibility, a high fat diet (HFD) predisposes mice with oncogenic K-ras activation to accelerated pancreatic intraepithelial neoplasm (PanIN) development. Tumor promotion is closely associated with increased inflammation and abrogation of TNFR1 signaling significantly blocks this process underlining a central role for TNFalpha in obesity-mediated enhancement of PanIN lesions. Interestingly, however, despite increased TNFalpha levels, mice remain insulin sensitive. We show that, while aggravating tumor promotion, a HFD exerts dramatic changes in energy metabolism through enhancement of pancreatic exocrine insufficiency, metabolic rates, and expression of genes involved in mitochondrial fatty acid (FA) beta-oxidation that collectively contribute to improved glucose tolerance in these mice. While on one hand these findings provide significant evidence that obesity is linked to tumor promotion in the pancreas, on the other it suggests alterations in inflammatory responses and bioenergetic pathways as the potential underlying cause.

CD34+ enriched cell products intended for autologous transendocardial CD34+ cell transplantation release significant amounts of angiopoietin-1.

OBJECTIVES: Cell-based therapy has emerged as a promising strategy for the treatment of patients with heart failure. Increasing evidence supports the hypothesis that paracrine mechanisms mediated by soluble factors released by the cells play a predominate role in reparative processes. The aim of our study was to analyze which cytokines are released by CD34+ enriched cell products intended for autologous transendocardial CD34+ cell transplantation in patients with cardiomyopathy. MATERIAL AND METHODS: The peripheral blood CD34+ cells from 12 patients were mobilized with granulocyte colony-stimulating factor, collected via apheresis and enriched by immunoselection. RESULTS: In CD34+ enriched cell population, hematopoietic, but not mesenchymal or endothelial, progenitors were detected. Except for angiopoietin-1, other measured cytokines (FGF1, FGF2, VEGF, PDGF, IL-6, HGH, SDF-1α/CXCL12, NRG1) were not released by CD34+ cells. The average concentration of angiopoietin-1 released by 5×106 CD34+ cells grown in neutral DMEM medium was 213.6±130.0pg/mL (range: 74-448pg/mL). Angiopoietin-1 secretion correlated well with CD34+ cell's capacity for generating colonies derived from hematopoietic progenitors (Pearson's correlation=0.964; P<0.001). CONCLUSION: Our study presents angiopoietin-1 as an interesting candidate and suggests future studies to explore how its release by CD34+ cells might impact the success of autologous CD34+ cell transplantation.

A new method for selective measurement of joint movement in hand tremor in Parkinson's disease patients.

Parkinson's disease (PD) is a progressive degenerative disorder of the central nervous system with tremor being one of its four main clinical features. Currently used methods can directly evaluate tremor amplitude and frequency but not joint movement in the affected limb. Measurement of joint movement facilitates the location of muscle groups that participate in PD tremor and this is important for treatment with local botulinum toxin injections. We developed and tested a method that measured tremor amplitude and frequency in a specific joint of the hand in PD patients. The tremor analysis method was based on force transducers adapted to record rest tremor of the wrist and metacarpophalangeal joints in two degrees of freedom for each joint. Direct measurements of joint movement in the hand can evaluate tremor amplitude and frequency and also locate the muscle groups that are most active in tremor movement, thus enabling their local treatment.

Proximate causes for diet-induced obesity in laboratory mice: a case study.

BACKGROUND/OBJECTIVES: Detailed protocols and recommendations for the assessment of energy balance have been provided to address the problems associated with different body mass and body composition as apparent for mouse models in obesity research. Here, we applied these guidelines to investigate energy balance in two inbred mouse strains with contrasting susceptibilities for diet-induced obesity (DIO). Mice of the AKR/J strain are highly susceptible, whereas the SWR/J mice are almost completely resistant. The proximate mechanisms responsible for this striking phenotypic difference are only partially understood. SUBJECTS/METHODS: Body mass and body composition, metabolizable energy, energy expenditure (EE), body temperature and spontaneous physical activity behavior were first assessed in a cohort of male AKR/J (N=29) and SWR/J (N=30) mice fed on a low-fat control diet (CD) to identify metabolic adaptations determining resistance to DIO. Thereafter, the immediate metabolic responses to high-fat diet (HFD) feeding for 3 days were investigated. Groups of weight-matched AKR/J (N=8) and SWR/J (N=8) mice were selected from the initial cohort for this intervention. RESULTS: Strain differences in body mass, fat mass and lean mass were adjusted by body mass as this was the only covariate significantly correlated with metabolizable energy and EE. On the CD, EE and fat oxidation was higher in SWR/J than in AKR/J mice, whereas no difference was found for metabolizable energy. In response to HFD feeding, both strains increased metabolizable energy intake, but also increased EE, body temperature, and fat oxidation. The catabolic adaptations to HFD feeding opposed the development of positive energy balance. Increased EE was not due to increased spontaneous physical activity. A significant strain difference was found when balancing metabolizable energy and daily energy expenditure (DEE). CONCLUSIONS: The guidelines were applicable with some limitations related to the adjustment of differences in body composition. Metabolic phenotyping revealed that metabolizable energy, DEE and metabolic fuel selection all contribute to the development of DIO. Therefore, assessing both sides of the energy balance equation is essential to identify the proximate mechanisms.

PC1/3 and PC2 gene expression and post-translational endoproteolytic pro-opiomelanocortin processing is regulated by photoperiod in the seasonal Siberian hamster (Phodopus sungorus).

A remarkable feature of the seasonal adaptation displayed by the Siberian hamster (Phodopus sungorus) is the ability to decrease food intake and body weight (by up to 40%) in response to shortening photoperiod. The regulating neuroendocrine systems involved in this adaptation and their neuroanatomical and molecular bases are poorly understood. We investigated the effect of photoperiod on the expression of prohormone convertases 1 (PC1/3) and 2 (PC2) and the endoproteolytic processing of the neuropeptide precursor pro-opiomelanocortin (POMC) within key energy balance regulating centres of the hypothalamus. We compared mRNA levels and protein distribution of PC1/3, PC2, POMC, adrenocorticotrophic hormone (ACTH), alpha-melanocyte-stimulating hormone (MSH), beta-endorphin and orexin-A in selected hypothalamic areas of long day (LD, 16:8 h light:dark), short day (SD, 8:16 h light:dark) and natural-day (ND, photoperiod depending on time of the year) acclimated Siberian hamsters. The gene expression of PC2 was significantly higher within the arcuate nucleus (ARC, P < 0.01) in SD and in ND (versus LD), and is reflected in the day length profile between October and April in the latter. PC1/3 gene expression in the ARC and lateral hypothalamus was higher in ND but not in SD compared to the respective LD controls. The immunoreactivity of PC1/3 cleaved neuropeptide ACTH in the ARC and PC1/3-colocalised orexin-A in the lateral hypothalamus were not affected by photoperiod changes. However, increased levels of PC2 mRNA and protein were associated with higher abundance of the mature neuropeptides alpha-MSH and beta-endorphin (P < 0.01) in SD. This study provides a possible explanation for previous paradoxical findings showing lower food intake in SD associated with decreased POMC mRNA levels. Our results suggest that a major part of neuroendocrine body weight control in seasonal adaptation may be effected by post-translational processing mediated by the prohormone convertases PC1/3 and PC2, in addition to regulation of gene expression of neuropeptide precursors.

High fat diet-induced modifications in membrane lipid and mitochondrial-membrane protein signatures precede the development of hepatic insulin resistance in mice.

OBJECTIVE: Excess lipid intake has been implicated in the pathophysiology of hepatosteatosis and hepatic insulin resistance. Lipids constitute approximately 50% of the cell membrane mass, define membrane properties, and create microenvironments for membrane-proteins. In this study we aimed to resolve temporal alterations in membrane metabolite and protein signatures during high-fat diet (HF)-mediated development of hepatic insulin resistance. METHODS: We induced hepatosteatosis by feeding C3HeB/FeJ male mice an HF enriched with long-chain polyunsaturated C18:2n6 fatty acids for 7, 14, or 21 days. Longitudinal changes in hepatic insulin sensitivity were assessed via the euglycemic-hyperinsulinemic clamp, in membrane lipids via t-metabolomics- and membrane proteins via quantitative proteomics-analyses, and in hepatocyte morphology via electron microscopy. Data were compared to those of age- and litter-matched controls maintained on a low-fat diet. RESULTS: Excess long-chain polyunsaturated C18:2n6 intake for 7 days did not compromise hepatic insulin sensitivity, however, induced hepatosteatosis and modified major membrane lipid constituent signatures in liver, e.g. increased total unsaturated, long-chain fatty acid-containing acyl-carnitine or membrane-associated diacylglycerol moieties and decreased total short-chain acyl-carnitines, glycerophosphocholines, lysophosphatidylcholines, or sphingolipids. Hepatic insulin sensitivity tended to decrease within 14 days HF-exposure. Overt hepatic insulin resistance developed until day 21 of HF-intervention and was accompanied by morphological mitochondrial abnormalities and indications for oxidative stress in liver. HF-feeding progressively decreased the abundance of protein-components of all mitochondrial respiratory chain complexes, inner and outer mitochondrial membrane substrate transporters independent from the hepatocellular mitochondrial volume in liver. CONCLUSIONS: We assume HF-induced modifications in membrane lipid- and protein-signatures prior to and during changes in hepatic insulin action in liver alter membrane properties - in particular those of mitochondria which are highly abundant in hepatocytes. In turn, a progressive decrease in the abundance of mitochondrial membrane proteins throughout HF-exposure likely impacts on mitochondrial energy metabolism, substrate exchange across mitochondrial membranes, contributes to oxidative stress, mitochondrial damage, and the development of insulin resistance in liver.

Regeneration of the radial nerve in a dog influenced by electrical stimulation.

The effect of biphasic electric fields on nerve regeneration that follows injury to the left radial nerve of a dog was examined using electromyography (EMG). The left and right radial nerves were crushed with a serrated hemostat and the stimulating electrodes were positioned proximally and distally relative to the site of the injury. The left nerves received rectangular, biphasic current pulses (30µA, 0.5Hz) through the lesion for two months. The right radial nerves were treated as controls and regenerated without electrical stimulation. EMG activity was recorded intramuscularly from left and right musculus extensor digitorum (from Medical dictionary) communis (MEDC). Results obtained at the end of the two-month stimulation period showed a significant difference between the EMG activity of the stimulated and the unstimulated MEDC suggesting that the electrical treatment enhanced the nerve regeneration.

Autocatalytic processing of recombinant human procathepsin B is a bimolecular process.

Cathepsin B and other lysosomal cysteine proteinases are synthesized as inactive zymogens, which are converted to their mature forms by other proteases or by autocatalytic processing. Procathepsin B autoactivation was shown in vitro at pH 4.5 to be a bimolecular process with K(s) and k(cat) values of 2.1+/-0.9 microM and 0.12+/-0.02 s(-1)6.0. However, in the presence of 0.5 microg/ml of dextran sulfate, relatively rapid processing is observed even at pH 6.5 (t(1/2) approximately 90 min), suggesting that glycosaminoglycans are involved in in vivo processing of lysosomal cysteine proteases.

Recording of electroneurograms from the nerves innervating the pancreas of a dog.

Electroneurograms (ENGs) from the vagus, splanchnic and pancreatic nerves innervating the pancreas of a dog, were recorded with chronically implanted silicone multi-electrode circular cuffs in an intact pancreas and in a pancreas partly disabled with alloxan. The cuffs contained 33 platinum electrodes (0.6x1.5 mm) arranged in three parallel circular groups integrated into the inner surface of the cuff. Each circular group contained 11 electrodes at a distance of 0.5 mm apart, with 6 mm between the circular groups. The cuffs had an inner diameter of 2.5 mm and the length of 18 mm. In a 2-year study, the cuffs were implanted into two adult Beagle dogs (one female and one male). In the vagus nerve, the cuff was installed on the nerve at the neck, whilst in the splanchnic nerve, the cuff was installed on the nerve before the celiac ganglion, and in the pancreatic nerve, the cuff was installed on the nerve just before it enters the pancreas. In each of the three implanted cuffs, the electrodes of the central circular group were connected to each other and this signal provided one input to a multi-channel ENG amplifying system. The electrodes of each of the two outer spiral groups were connected to each other and then both these groups were short-circuited. This signal then provided another input to the multi-channel ENG amplifying system. The ENG amplifying system was designed to amplify the ENGs 100000 times and to pass frequencies of between 500 and 10 kHz. In our study, three recordings in each animal were conducted. Recordings in the intact pancreas were conducted 2 and 6 months after the implantation, while the recording in the partly disabled pancreas, was conducted 10 months after the implantation and 10 days after the disablement. Due to the fact that the results obtained in both animals were actually quite similar, we present the results of the recordings obtained in one animal. In both animals the cuffs were left implanted for more than 1 year and were used for pancreatic stimulation, although this is not in this paper. The results show that cuffs implanted chronically on the nerves innervating the pancreas of a dog could reliably record the ENGs. This information could be used effectively in further study of pancreatic innervation and its function. Moreover, the results suggest that cuffs could also be useful in recording the ENGs from other nerves of the autonomic nervous system that innervate various glands and internal organs.

Modulation of hormone secretion by functional electrical stimulation of the intact and incompletely dysfunctional dog pancreas.

The purpose of the present study was to modulate the secretion of insulin and glucagon in Beagle dogs by stimulation of nerves innervating the intact and partly dysfunctional pancreas. Three 33-electrode spiral cuffs were implanted on the vagus, splanchnic and pancreatic nerves in each of two animals. Partial dysfunction of the pancreas was induced with alloxan. The nerves were stimulated using rectangular, charge-balanced, biphasic, and constant current pulses (200 micros, 1 mA, 20 Hz, with a 100-micros delay between biphasic phases). Blood samples from the femoral artery were drawn before the experiment, at the beginning of stimulation, after 5 min of stimulation, and 5 min after the end of stimulation. Radioimmunoassay data showed that in the intact pancreas stimulation of the vagal nerve increased insulin (+99.2 microU/ml) and glucagon (+18.7 pg/ml) secretion and decreased C-peptide secretion (-0.15 ng/ml). Splanchnic nerve stimulation increased insulin (+1.7 microU/ml), C-peptide (+0.01 ng/ml), and glucagon (+50 pg/ml) secretion, whereas pancreatic nerve stimulation did not cause a marked change in any of the three hormones. In the partly dysfunctional pancreas, vagus nerve stimulation increased insulin (+15.5 microU/ml), glucagon (+11 pg/ml), and C-peptide (+0.03 ng/ml) secretion. Splanchnic nerve stimulation reduced insulin secretion (-2.5 microU/ml) and increased glucagon (+58.7 pg/ml) and C-peptide (+0.39 ng/ml) secretion, and pancreatic nerve stimulation increased insulin (+0.2 microU/ml), glucagon (+5.2 pg/ml), and C-peptide (+0.08 ng/ml) secretion. It was concluded that vagal nerve stimulation can significantly increase insulin secretion for a prolonged period of time in intact and in partly dysfunctional pancreas.

Selective recording of electroneurograms from the sciatic nerve of a dog with multi-electrode spiral cuffs.

Electroneurograms (ENGs) from superficial regions of the sciatic nerve of a Beagle dog were recorded selectively with a chronically implanted 33-electrode spiral cuff (cuff). By delivering stimulating pulses to groups of three electrodes (GTEs) within the cuff we could define the relative positions of the particular superficial regions that selectively innervated the tibialis anterior (TA) and gastrocnemius muscles (GM). GTEs with and without contractions of the TA and GM muscles were selected and connected to a 4-channel ENG system designed to amplify ENGs by 100,000 times and to pass frequencies between 500 Hz and 10 kHz. In our study, 12 experiments were conducted on three Beagle dogs with a cuff implanted for up to 2 years. We present the results obtained in four experiments conducted on one animal. With the implanted leg mounted in a special electronic brace we applied extending forces to the ankle, rotating it by up to 37 degrees according to the neutral position, eliciting torque to stretch the TA muscle. Only the ENG from a GTE eliciting maximum contraction of the TA muscle showed activities corresponding to the trajectory of the mechanical load of the muscle. Next, we dissected the calcanean tendon (CT) of the implanted leg and applied repetitive pull forces to the CT. Only the ENG from the GTE eliciting maximum contraction of the GM muscle was activated in correspondence to the trajectory of the mechanical load applied on the CT. The results suggest that the cuff, implanted chronically on the sciatic nerve, is useful to record ENGs of the afferent fibers from TA and GM muscles selectively and that the technique could be extended for human use in the field of rehabilitation for paralysis.

Multielectrode spiral cuff for selective stimulation of nerve fibres.

In this paper we present the modelling, design, and initial experimental testing of a nerve cuff multielectrode system for selective stimulation of fibres in superficial peripheral nerve trunk regions which is capable of making a selective activation of multiple muscles. The developed multielectrode nerve cuff consists of 14 platinum stimulating electrodes embedded within a self-curling sheet of biocompatible insulation, exhibiting a spiral transverse cross-section. The spiral shape of the system is such that the number of stimulating electrodes which can be utilized depends on the diameter of the stimulated nerve. Nerves with a greater diameter automatically make use of more electrodes than thin ones. The development was based on results obtained by a histological examination of the peripheral nerves which were planned to be stimulated, and on models of excitation of myelinated nerve fibres. The modelling objectives were to determine the electric field that would be generated within a nerve trunk by a specific electrode. Moreover, the extent of initial excitation of the nerve fibres within the superficial region of the dog sciatic nerve elicited by a certain discrete stimulating electrode was predicted. For this purpose a calculation of activating function for six positions where the nerve fibres were supposed to lie within the longitudinally dissected sciatic nerve was performed. In two acute experiments on the sciatic nerve of the dog the objective was to characterize the effectiveness of the multielectrode system in monopolar selective stimulation of the superficial regions, innervating the gastrocnemius and tibialis anterior muscle. A selectivity preliminary tested by measuring the myoelectric activity of the gastrocnemius and tibialis anterior muscle after 2 months showed good results in both animals.

Evaluation of the strength of elbow flexors in patients with neuromuscular diseases.

In planning the optimum treatment for patients with neuromuscular diseases (NMD), it is essential to know as much as possible about their functional state. Assessment of the strength of certain muscles is the most direct measure of motor deficiency. In the development of normative data needed for patients with NMD, the use of torque measurements is required. Forty-nine patients (31 men and 18 women),f rom 18 to 54 years (mean age 33 +/- 8.9 years), were included in the study. Five groups of patients, each having one of five different NMDs, were formed. We tested unilaterally the biceps brachii muscle that normally generates the highest torque. For this purpose an eletronic brace enabling isometric measurements of torque during elbow flexion was designed. The patients produced three maximum voluntary elbow flexions that lasted about 3 s and separated by a pause of about 3 s. Force development was rapid with continuous build-up and isometric. About 15 s later the patients produced the last maximum voluntary elbow flexion, keeping it as stable aspossible for a period of 30 s. Patients with mitochondrial myopathy (MM), having the shortest mean half fatigue time (4.3 s), elicited the highest mean torque in both short maximum voluntary elbow flexions (1.34 Nm) as well as in the 30 s-long maximum voluntary elbow flexions. In contrast, patients with facioscapulohumeral muscular dystrophy (MD-FSH), having the longest mean half-fatigue time (15.4 s), elicited the lowest mean torque in both the short maximum voluntary (0.29 Nm) as well as in 30 s-long maximum voluntary elbow flexions. Patients with Becker muscular dystrophy (MD-B), having a mean half-fatigue time (11.1 s) slightly shorter than the patients with MD-FSH, elicited a higher mean torque in both the short (0.82 Nm) and the 30 s-long elbow flexions. Finally, patients with limb-girdle muscular dystrophy (MD-RM) and spinal muscular atrophy type 3 (SMA3), having a similar mean half-fatigue time (6.9 s for patients with MD-RM and 7.4 s for patients with SMA3), also elicited similar torque in both short (0.45 Nm for patients with MD-RM and 0.65 Nm for patient with SMA3) and 30 s-long elbow flexions. The results of the study show that the methodology developed to quantitative measure the torque of elbow flexions in patients with NMD enables the characteristics and natural course of NMD to be more objectively documented. Accordingly, the optimum treatmentforpatients with NMD could be restored.

Platinum stimulating electrodes in physiological media.

The study reported here seeks to characterize behaviour of platinum electrodes of the 45-electrode spiral nerve cuff for selective electrical stimulation of different superficial regions of peripheral nerves in physiological solution (0.9% NaCl) and Eliott's buffered solution. Each electrode of the spiral cuff had a flat geometric surface of 2 mm2. To delineate an operational potential window between hydrogen and oxygen evolution during stimulation the electrochemical technique of cyclic voltammetry was used. In a typical cyclic voltammetry experiment, the potential of the tested electrode was cycled at an appropriate rate between two potential limits. The surfaces of the electrodes, obtained after injection of the biphasic charge as defined in a physiological solution (0.9% NaCl), thus simulating long-term electrical stimulation, were investigated using a high resolution Auger electron spectroscopy (AES) method.

Force transducer for measurement of muscle contraction.

Single channel force transducers, intended for measurement and evaluation curves of preconditioned fibres in muscles contracting synergistically during direct or indirect electric stimulation of isolated muscle, were designed, developed and experimentally tested. The force transducers were made up of a full Wheatstone bridge composed of four semiconductor strain gauges bonded on a specially designed cantilever. The transducers with a natural frequency 350 Hz and compliance of 0.25 micron g-1 represents a very linear dependence of the output voltage upon the load giving a sensitivity for the transducers of 0.5 mV mN-1 with a bridge excitation voltage of 5 V. The nominal range of each transducer is 0-70 mN. The system is able to record even a contraction of only a few muscle fibres, both single twitches as well as sustained tonic contractions.