Reactive postural adjustment in response to predictable and unpredictable perturbations in healthy adults: A comparison between swayback, hyperlordotic and erect postures.

BACKGROUND: Promoting an erect posture in standing has been advocated to offer superior protection to the spine when compared to hyperlordotic and swayback postures. RESEARCH QUESTION: Do postural adjustments towards external perturbation differ between erect, hyperlordotic and swayback postures? If so, which posture offers better protection to lumbar spine? METHODS: Forty-four healthy adults received top-down perturbations under unpredictable (without visual-and-auditory input) and predictable (with visual-and-auditory input) conditions in three simulated postures: erect, hyperlordotic, and swayback. Postural adjustments namely the centre of pressure parameters, joint angle onsets, and neuromuscular responses measured by muscle onsets and co-contraction between muscle pairs upon the perturbation were compared using the two-way repeated measures ANOVA. Post-hoc analysis with Bonferroni correction was conducted to identify the between-posture differences for the respective postural adjustment parameters. RESULTS: Path length, ellipse area and average velocity of centre of pressure were significantly greater under unpredictable condition as compared to predictable condition (p < 0.001). Significant between-posture difference was detected in centre of pressure path length (p < 0.035), pelvic tilt onset (p < 0.038) and all muscle co-contraction indexes (p < 0.001). Post-hoc analysis revealed significantly smaller centre of pressure path length in erect posture as compared to hyperlordotic and swayback postures (p < 0.01) under unpredictable conditions. Significantly greater co-contraction indexes of lumbar multifidus and erector spinae, and internal oblique and lumbar multifidus were found in hyperlordotic as compared to erect and swayback postures (p < 0.05). SIGNIFICANCE: Compared to erect posture, adoption of hyperlordotic and swayback postures altered the contributions of the active and passive subsystems of the spine that regulates postural control upon external perturbations. Such differences in neuromuscular control may lessen the capacity of the human spine to withstand loading and shear forces. Prospective studies are required to validate if habitually adopted hyperlordotic and swayback postures contribute to an earlier/ higher prevalence of spinal dysfunctions.

Outbreak of enzootic ataxia in goats and sheep in the state of Bahia / Surto de ataxia enzoótica em caprinos e ovinos no estado da Bahia

The objective of this study was to describe for the first time the clinical-epidemiological, laboratory and pathological aspects of different forms of enzootic ataxia in goats and lambs in the state of Bahia, as well as to propose an emergency oral treatment with copper sulfate in an individualized way for neonates. Three outbreaks of enzootic ataxia were studied. The history, clinical signs and epidemiological data were obtained from the owners and checked during the visits. The first outbreak (FO) occurred in 2013 in a property located in the municipality of Itaberaba and affected a herd composed of 90 goats and 130 sheep. The second outbreak (SO) occurred in 2014 in the municipality of Santa Luz and affected a herd of 90 goats and 110 sheep. The third outbreak (TO) occurred in 2018, in a property located in the same municipality of the SO, being the herd constituted by 80 sheep. Samples of blood were collected from all goats and sheep treated for serum copper dosage. Nine animals (five goats and four sheep) that presented a more severe clinical picture and unfavorable prognosis were necropsied for diagnostic confirmation. During the necropsy of the FO, SO and TO animals, liver samples were collected for copper dosage as well as fragments of several organs for histopathology. At the site where the SO occurred, samples of soil and the main forages where the animals were kept were collected to determine copper, iron, molybdenum, sulfur and zinc contents. The clinical and histopathological findings in the three outbreaks studied were characteristic of enzootic ataxia. In the outbreaks studied, the frequency of enzootic ataxia was higher in goats (52) than in lambs (39). In the goats the mean values of serum copper (0.05mg/kg) and hepatic (2.48mg/kg) of the FO and SO were well below their respective reference values, 12 times lower than serum levels and eight times lower in relation to liver contents. On the other hand, TO sheep presented mean values of serum copper (0.015mg/kg) reduced by 40 times. The levels of iron and sulfur were high in the fodder of the property where the SO occurred, already in the soil, iron levels were high and copper levels were reduced. The treatment tested in neonates and lambs with two doses of copper sulphate solution orally at a dose of 20mg/kg for sheep and 35mg/kg for goats during the first and second week of life was effective in prevention of enzootic ataxia in neonates and can be used for emergency control of the disease. The occurrence of enzootic ataxia (congenital and late form) in goats and sheep was first reported in Bahia. It is also worth noting that this disease caused by copper deficiency has caused great damage to the breeders of small ruminants, mainly due to the high mortality of the animals affected.(AU)

Objetivou-se com esse estudo descrever pela primeira vez os aspectos clínico-epidemiológicos, laboratoriais e patológicos de diferentes formas de ataxia enzoótica em cabritos e borregos no estado da Bahia, bem como propor um tratamento oral emergencial com sulfato de cobre de forma individualizada para neonatos. Foram estudados três surtos de ataxia enzoótica. O histórico, sinais clínicos e dados epidemiológicos foram obtidos com os proprietários e verificados durantes as visitas técnicas. O primeiro surto (PS) ocorreu em 2013 em uma propriedade localizada no município de Itaberaba e acometeu um rebanho composto por 90 caprinos e 130 ovinos. O segundo surto (SS) aconteceu em 2014 no município de Santa Luz e afetou um rebanho formado por 90 caprinos e 110 ovinos. O terceiro surto (TS) ocorreu 2018, em uma propriedade localizada no mesmo município do SS, sendo o rebanho constituído por 80 ovinos. Amostras de sangue foram colhidas de todos os caprinos e ovinos atendidos, para dosagem de cobre sérico. Nove animais (cinco caprinos e quatro ovinos) que apresentavam quadro clínico mais grave e prognóstico desfavorável foram necropsiados para confirmação diagnóstica. Durante a necropsia dos animais do PS, SS e TS amostras de fígado foram coletadas para dosagem de cobre, bem como amostras de diversos órgãos para exame histopatológico. Na propriedade onde ocorreu o SS, foram coletadas amostras de solo e das principais forragens onde os animais eram mantidos, a fim de se determinar os teores de cobre, ferro, molibdênio, enxofre e zinco. Os achados clínicos e histopatológicos verificados nos três surtos estudados foram característicos de ataxia enzoótica. Nos surtos estudados, a frequência da ataxia enzoótica foi maior em cabritos (52) do que em cordeiros (39). Nos caprinos os valores médios de cobre sérico (0,05mg/kg) e hepático (2,48mg/kg) do PS e SS encontravam-se muito abaixo dos respectivos valores de referência, sendo 12 vezes menor em relação aos níveis séricos e oito vezes menor em relação aos teores hepáticos. Já os ovinos do TS apresentavam valores médios de cobre sérico (0,015mg/kg) reduzidos cerca de 40 vezes. Os teores de ferro e enxofre encontravam-se elevados nas forragens da propriedade onde ocorreu o SS, já no solo, os níveis de ferro apresentavam-se elevados e os de cobre reduzidos. O tratamento testado nos cabritos e borregos neonatos, com duas administrações individualizadas com solução de sulfato de cobre, por via oral, na dose de 20mg/kg para ovinos e 35mg/kg para caprinos, na primeira e segunda semana de vida, foi eficaz na prevenção da ataxia enzoótica nos neonatos e pode ser utilizado para controle emergencial da doença. Comprovou-se pela primeira vez na Bahia a ocorrência da ataxia enzoótica (forma congênita e tardia) em caprinos e ovinos. Ressalta-se ainda que, esta doença causada por deficiência de cobre, tem cursado com grandes prejuízos aos criadores de pequenos ruminantes, sobretudo, devido à alta mortalidade dos animais acometidos.(AU)

Avaliação epidemiológica, clínica, anatomopatológica e etiológica de surtos de ataxia em cabritos e cordeiros / Epidemiological, clinical, etiological and histopatological evaluation of delayed enzootic ataxia outbreaks in kids and lambs

Nos anos de 2001 e 2002, 46 cabritos (CAB) e 35 cordeiros (COR) de uma propriedade do agreste do Estado de Pernambuco foram acometidos por ataxia enzoótica (AE) de forma tardia. Houve aumento da incidência do 1o ano (46,3 por cento - CAB; 24,2 por cento COR) para o ano subseqüente (100 por cento - CAB e COR). Somente no ano de 2001, houve maior incidência em CAB (P<0,002) que nos COR. Todos os animais acometidos sucumbiram, com exceção de um CAB e um de COR. O quadro clínico variou de acordo com a idade em que surgiram os sintomas, ou seja, de 30 a 45 dias os animais manifestaram paralisia dos membros anteriores e posteriores, acompanhada de espasticidade muscular e morte; com mais de 45 dias, ocorreu paralisia flácida ou espástica apenas dos membros posteriores e morte; somente os cabritos com menos de 45 dias apresentaram movimentos verticais de cabeça. As lesões histopatológicas evidenciadas foram: degeneração axonal, esferóides, gliose e dismielinização no segmento ventral e lateral da medula espinhal. Nos animais com menos de 45 dias, essas lesões foram evidentes na região cervical e nos animas mais velhos na região lombar. Apenas nos cabritos foi constatada lesão degenerativa no cerebelo. A dieta oferecida ao rebanho continha quantidades adequadas de cobre, porém os animais acometidos por AE apresentaram baixos teores de cobre no fígado (45,8mg kg-1 MS). Os elementos antagonizantes do cobre, Mo, S, e Zn, estavam normais, com exceção do ferro, que estava em alta concentração tanto no solo (8600mg kg-1) quanto nos alimentos (284mg kg-1). O excesso de ingestão de ferro sugere ter provocado a carência de cobre nos animais.

The effect of gastrointestinal parasitism on blood copper and hemoglobin levels in sheep.

Endoparasitism is a problem in Trinidad, as it is in most tropical countries. Parasite infection has been suspected to contribute to the pathogenesis of swayback disease (which is also prevalent in Trinidad), but the mode of action has not been clearly defined, although it has been suggested that parasites interfere with the absorption of copper from the gastrointestinal tract. The objectives of the study were to assess the effect of endoparasitism on blood copper levels and hemoglobin (Hb) concentration in sheep in Trinidad. Copper was administered intramuscularly to parasite infected and noninfected animals. The results showed that parasitism has a depressing effect on blood copper and Hb levels, even when administered parenterally. It is concluded that parasitism can aggravate existing hypocupremia and possibly influence the expression of swayback disease.

The effect of gastrointestinal parasitism on blood copper and hemoglobin levels in sheep

Endoparasitism is a problem in Trinidad, as it is in most tropical countries. Parasite infection has been suspected to contribute to the pathogenesis of swayback disease (which is also prevalent in Trinidad), but the mode of action has not been clearly defined, although it has been suggested that parasites interfere with the absorption of copper from the gastrointestinal tract. The objectives of the study were to assess the effect of endoparasitism on blood copper levels and hemoglobin (Hb) concentration in sheep in Trinidad. Copper was administered intramuscularly to parasite infected and noninfected animals. The results showed that parasitism has a depressing effect on blood copper and Hb levels, even when administered parenterally. It is concluded that parasitism can aggravate existing hypocupremia and possibly influence the expression of swayback disease.

Cytochrome-c oxidase isolated from the brain of swayback-diseased sheep displays unusual structure and uncharacteristic kinetics.

Swayback disease, a neurodegenerative disorder of lambs, and Menkes disease, the human equivalent, are caused by a deficiency of dietary copper. Reports of low enzymic activity suggest that several copper-containing enzymes, including cytochrome-c oxidase (COX), may influence the progress of these diseases. To investigate its role in the development of neurodegenerative disorders, in particular swayback disease, we isolated COX from the brains and livers of swayback-diseased lambs. Comparative sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) combined with densitometric analysis revealed that whereas the structure of COX from the liver of diseased animals was normal, the corresponding brain enzyme was subunits II-, III-, and IV-deficient; the deficiency was 55, 30, and 65% respectively. The activities of liver and brain COX from normal and diseased lambs were compared by polarographic assay at low ionic strength. Whereas the enzyme from normal brains and both forms of the liver enzyme yielded characteristic biphasic Eadie-Hofstee plots, the brain enzyme from diseased animals displayed a single phase with a K(m) of 4.7 +/- 2.4 x 10(-6) M: the K(m) values of COX from the normal brain were 12 +/- 2.5 x 10(-6) and 5.5 +/- 0.5 x 10(-7) M. We conclude that the altered enzyme structure accounts for the uncharacteristic kinetics and low activity we have observed for the isolated brain enzyme. We also conclude that the altered enzyme structure partly accounts for the low oxidase activity and decreased ATP synthesis that has been widely reported for brain tissue from swayback-diseased animals. We postulate that the subunit deficiency probably results from incomplete crosslinking between the subunits and the membrane, and predict that similar structural and kinetic factors may also account for low COX activity in Menkes disease.

Histopathology of enzootic ataxia in Sika deer (Cervus nippon Temminck).

Thirteen Sika deer (Cervus nippon Temminck) showing ataxia on a stock farm in the north eastern district of China were examined histopathologically. The principal pathological changes were spongy vacuolation and myelin deficiency in the white matter of the spinal cord and brain stem, fibrosis and rupture of the elastic lamina of the spinal arterioles, and mesothelial hyperplasia in the spinal arachnoid. Other findings included defective formation of the elastic laminae of the aorta, and the blood vessels in the kidney and lung, hemosiderosis in the spleen and liver, and lymphocyte depletion in the systemic lymph nodes. Copper concentrations were low in the serum and liver. In the white matter of the spinal cord and brain stem, demyelination appeared to coexist with dysmyelination and secondary myelin breakdown. It was inferred that decreased activity of copper containing enzyme induced various lesions. The possible role of copper deficiency in the pathogenesis of the ataxic conditions is discussed.

Swayback in a blesbok (Damaliscus dorcas phillipsi) and a black wildebeest (Connochaetes gnou).

Ataxia associated with myelopathy and low liver copper concentrations is described in a blesbok (Damaliscus dorcas phillipsi) and black wildebeest (Connochaetes gnou) from the Karoo Nature Reserve, Graaff-Reinet. This syndrome, which occurs in neonatal and delayed forms, has been described in sheep, goats, pigs and domesticated red deer, but reports in other ungulates, including antelope, are very rare and generally unconfirmed by histopathological examination. The 2 animals examined exhibited a typical pattern of Wallerian degeneration in selected tracts of the spinal cord. Many blesbok in the reserve are markedly pale in colour. Fading of the hair is also associated with copper deficiency in ungulates. High lamb mortality occurs as a result of the ataxia and threatens the survival of the blesbok herd in the reserve. Confirmation of low liver copper concentrations in affected animals offers direction towards the solution of the problem.

Novel mitochondrial proteins and decreased intrinsic activity of cytochrome-c oxidase. Characteristics of swayback disease in sheep.

Swayback disease (SD), a fatal neurological disorder affecting lambs and kids, is characterized by abnormal mitochondria and low cytochrome-c oxidase activity. The cytochrome-c oxidase content and activity and the protein composition of mitochondria isolated from the brains of SD lambs were investigated. Difference spectra analysis indicated that the cytochrome-c oxidase content of mitochondria from SD animals was lower than normal, and electrophoresis showed that when compared to mitochondria from normal animals, lipid-depleted mitochondria from SD lambs had a different protein composition, particularly, in the 40-55 kDa region. Polarographic studies, using cytochrome-c as substrate, confirmed low intrinsic activity of cytochrome-c oxidase within the mitochondria of SD lambs. These studies also showed that at low ionic strength, such mitochondria did not yield the expected characteristic biphasic Eadie-Hofstee plots.

Ultrastructure of hepatocytes in copper-deficient Sika deer (Cervus nippon Temminck).

The livers of 13 Sika deer (Cervus nippon Temminck) aged 4 to 9 years and suffering from copper deficiency (enzootic ataxia) were examined histologically, histochemically and by electron microscopy. In addition, the serum and liver copper concentrations, measured in three animals, were found to be low. Histologically, the hepatocytes exhibited cloudy swelling, and numerous haemosiderin deposits were seen in the hepatocytes and Kupffer cells. Staining with p-dimethyl amino-benzylidene-rhodamine revealed distinctly fewer copper granules than normal. Histochemically, 3,3'-diaminobenzidine-H2O2 staining revealed increased numbers of catalase-positive granules around nuclei. Electron microscopically, "giant" and bizarre-shaped mitochondria, irregular depression of the mitochondrial membrane, and fusion of cristae were noted. Disorders of copper-containing enzymes, including cytochrome oxidase, caeruloplasmin and monoamine oxidase, may have been responsible for the mitochondrial abnormalities.

Studies on the relationship between sway disease of bactrian camels and copper status in Gansu province.

The clinical signs of camel sway disease in the Hexi Corridor of Gansu province were defined. The contents of eight minerals in soils, in forage and in the blood and hair of bactrian camels from this region were determined. The related blood indices were also measured. The concentration of molybdenum in soils and forage was 4.8 +/- 0.02 and 4.8 +/- 0.25 micrograms/g (dry matter), respectively, the copper to molybdenum ratio in the forage being only 1.3. The concentration of copper in blood and hair from the camels was 0.28 +/- 0.17 micrograms/ml and 3.50 +/- 1.00 micrograms/g, respectively. There was a hypochromic microcytic anaemia and a low level of ceruloplasmin in the blood. It is therefore suggested that sway disease of bactrian camels in this region is caused by secondary copper deficiency, mainly due to the high molybdenum content in soils and forage. The copper deficiency in the camels was aggravated during reproduction. Oral administration of copper sulphate can prevent and cure the disease.