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1.
Sci Rep ; 13(1): 9835, 2023 06 17.
Artigo em Inglês | MEDLINE | ID: mdl-37330586

RESUMO

This study investigated the effects of 67 species of macroalgae on methanogenesis and rumen fermentation in vitro. Specimens were analyzed for their effect on ruminal fermentation and microbial community profiles. Incubations were carried out in an automated gas production system for 24-h and macroalgae were tested at 2% (feed dry matter basis) inclusion rate. Methane yield was decreased 99% by Asparagopsis taxiformis (AT) when compared with the control. Colpomenia peregrina also decreased methane yield 14% compared with control; no other species influenced methane yield. Total gas production was decreased 14 and 10% by AT and Sargassum horneri compared with control, respectively. Total volatile fatty acid (VFA) concentration was decreased between 5 and 8% by 3 macroalgae, whereas AT reduced it by 10%. Molar proportion of acetate was decreased 9% by AT, along with an increase in propionate by 14%. Asparagopsis taxiformis also increased butyrate and valerate molar proportions by 7 and 24%, respectively, whereas 3 macroalgae species decreased molar proportion of butyrate 3 to 5%. Vertebrata lanosa increased ammonia concentration, whereas 3 other species decreased it. Inclusion of AT decreased relative abundance of Prevotella, Bacteroidales, Firmicutes and Methanobacteriaceae, whereas Clostridium, Anaerovibrio and Methanobrevibacter were increased. Specific gene activities for Methanosphaera stadtmane and Methanobrevibacter ruminantium were decreased by AT inclusion. In this in vitro study, Asparagopsis taxiformis was most effective in decreasing methane concentration and yield, but also decreased total gas production and VFA concentration which indicates overall inhibition of ruminal fermentation. No other macroalgae were identified as potential mitigants of enteric methane.


Assuntos
Alga Marinha , Animais , Metano/metabolismo , Rúmen/metabolismo , Ácidos Graxos Voláteis/metabolismo , Butiratos/metabolismo , Fermentação , Dieta , Ração Animal/análise , Digestão
3.
J Dairy Sci ; 105(3): 2288-2300, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35086703

RESUMO

The objective of this study was to investigate the effects of supplementation of an exogenous enzyme preparation (EEP) on performance, total-tract digestibility of nutrients, plasma AA profile, and milk fatty acids composition in lactating dairy cows fed a reduced-starch diet compared with a normal-starch diet (i.e., positive control). Forty-eight Holstein cows (28 primiparous and 20 multiparous) were enrolled in a 10-wk randomized complete block design experiment with 16 cows per treatment. Treatments were as follows: (1) normal-starch diet (control) containing (% dry matter basis) 24.8% starch and 33.0% neutral detergent fiber (NDF), (2) reduced-starch diet (RSD) containing 18.4% starch and 39.1% NDF, or (3) RSD supplemented with 10 g/cow per day of an EEP (ENZ). The EEP contained amylolytic and fibrolytic activities and was top-dressed on the total mixed ration at the time of feeding. Compared with normal-starch diet, dry matter intake and milk and energy-corrected milk (ECM) yields were lower (on average by 7.1, 9.5, and 7.2%, respectively) for cows on the RSD treatments. Concentrations, but not yields, of milk fat and total solids were increased by RSD. Energy-corrected milk feed efficiency did not differ among treatments. Total-tract digestibility of NDF tended to increase by RSD treatments. Plasma AA concentrations were not affected by treatment, except that of 3-methylhistidine was increased by ENZ, compared with RSD. Blood glucose concentration tended to be lower in cows on the RSD treatments, but ENZ increased glucose and tended to increase insulin concentrations at 4 h after feeding when compared with RSD. Cows on the RSD treatments had decreased concentrations of de novo fatty acids and tended to have increased concentrations of preformed fatty acids in milk. Overall, decreasing dietary starch concentration by 26% decreased dry matter intake, milk, and ECM yields, but ECM feed efficiency was not different among treatments. The negative effects of reducing dietary starch on production were not attenuated by the EEP.


Assuntos
Lactação , Amido , Ração Animal/análise , Animais , Bovinos , Dieta/veterinária , Suplementos Nutricionais , Digestão , Feminino , Leite , Rúmen , Amido/farmacologia
4.
J Dairy Sci ; 105(1): 313-328, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34756433

RESUMO

Two experiments were conducted to investigate the production effects of N-acetyl-l-methionine (NALM; experiment 1) and to estimate its bioavailability (BA) and rumen escape (RE; experiment 2), respectively, in lactating dairy cows. In experiment 1, 18 multiparous Holstein cows were used in a replicated, 3 × 3 Latin square design experiment with three 28-d periods. Treatments were (1) basal diet estimated to supply 45 g/d digestible Met (dMet) or 1.47% of metabolizable protein (MP; control), (2) basal diet top-dressed with 32 g/d of NALM to achieve dMet supply of 2.2% of MP, and (3) basal diet top-dressed with 56 g/d of NALM to achieve dMet supply of 2.6% of MP. The NALM treatments supplied estimated 17 and 29 g/d dMet from NALM, respectively, based on manufacturer's specifications. In experiment 2, 4 rumen-cannulated lactating Holstein cows were used in a 4 × 4 Latin square design experiment with four 12-d periods. A 12-d period for baseline data collection and 4 d for determination of RE of NALM preceded the Latin square experiment. For determination of RE, 30 g of NALM were dosed into the rumen simultaneously with Cr-EDTA (used as a rumen fluid kinetics marker) and samples of ruminal contents were collected at 0 (before dosing), 1, 2, 4, 6, 8, 10, 14, 18, and 24 h after dosing. Rumen escape of NALM was calculated using the estimated passage rate based on the measured Cr rate of disappearance. Bioavailability of abomasally dosed NALM was determined using the area under the curve of plasma Met concentration technique. Two doses of l-Met (providing 7.5 and 15 g of dMet) and 2 doses of NALM (11.2 and 14.4 g of dMet) were separately pulse-dosed into the abomasum of the cows and blood was collected from the jugular vein for Met concentration analysis at 0 (before dosing), 1, 2, 4, 6, 8, 10, 12, 14, 18, and 24 h after dosing. Supplementation of NALM did not affect DMI, milk yield, feed efficiency, or milk protein and lactose concentrations and yields in experiment 1. Milk fat concentration and energy-corrected milk yield decreased linearly with NALM dose. Plasma Met concentration was not affected by NALM dose. The estimated relative BA of abomasally dosed NALM (experiment 2) was 50% when dosed at 14.4 g/cow (11.2 g/d dMet from NALM) and 24% when dosed at 28.8 g/cow (14.4 g/d dMet from NALM). The estimated RE of NALM was 19% based on the measured kp of Cr at 11%/h. The total availability of ingested NALM was estimated at 9.5% for the lower NALM dose when taking into account RE (19%) and bioavailability in the small intestine (50%). Overall, NALM supplementation to mid-lactation dairy cows fed a MP-adequate basal diet below NRC (2001) recommendations (45 g/d or 1.47% Met of MP) decreased milk fat and energy-corrected milk yields but did not affect milk or milk true protein yields. Further evaluation of BA of NALM at different doses is warranted. In addition, intestinal conversion of NALM to Met needs additional investigation to establish a possible saturation of the enzyme aminoacylase I at higher NALM doses.


Assuntos
Ração Animal , Lactação , Ração Animal/análise , Animais , Disponibilidade Biológica , Bovinos , Dieta/veterinária , Proteínas Alimentares/metabolismo , Suplementos Nutricionais , Feminino , Metionina/metabolismo , Rúmen/metabolismo
5.
J Dairy Sci ; 104(11): 11609-11620, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34419284

RESUMO

In ruminants, it has been observed that capsicum oleoresin can alter insulin responses and that high-intensity artificial sweetener can increase glucose absorption from the small intestine. Because glucose metabolism and insulin responses are critical during early lactation, these supplements might have an effect on the metabolic status of dairy cows during the transition period. The objective of this experiment was to evaluate the effects of rumen-protected capsicum oleoresin fed alone or in combination with artificial sweetener during the transition period on lactational performance and susceptibility to subclinical ketosis in dairy cows. Fifteen primiparous and 30 multiparous Holstein cows (a total of 39 cows finished the study) were arranged in a randomized complete block design during d -21 to 60 relative to parturition. Cows within block were randomly assigned to one of the following treatments: no supplement (CON), supplementation with 100 mg of rumen-protected capsicum/cow per day (RPCap), or RPCap plus 2 g of high-intensity artificial sweetener/cow per day (RPCapS). For both the RPCap and RPCapS treatments, only rumen-protected capsicum was fed during the dry period. From d 8 to 11 of lactation, intake was limited to 70% of predicted dry matter intake to induce subclinical ketosis. Production variables were recorded daily, samples for milk composition were collected on wk 2, 4, 6, and 8, and blood samples were collected on wk -2, 1, 2, and 4 of the experiment for analysis of metabolic hormones and blood cell counts. Supplementation with rumen-protected capsicum increased serum insulin and decreased ß-hydroxybutyrate concentrations precalving, indicating a decrease in lipolysis. During the lactation period, RPCap was associated with a trend for increased milk production and feed efficiency following the ketosis challenge. Supplementation with RPCapS appeared to negate the response to rumen-protected capsicum. All cows developed subclinical ketosis during the challenge, and this was not affected by treatment. We conclude that treatments did not decrease susceptibility to subclinical ketosis; however, dietary supplementation with rumen-protected capsicum was effective at improving energy status precalving and tended to increased milk production and feed efficiency. The mechanism underlying these responses is unclear.


Assuntos
Capsicum , Rúmen , Ração Animal/análise , Animais , Bovinos , Dieta/veterinária , Suplementos Nutricionais , Lactação , Leite
6.
J Dairy Sci ; 104(9): 9827-9841, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34253370

RESUMO

This study investigated the effects of an amylase-enabled corn silage on lactational performance, enteric CH4 emission, and rumen fermentation of lactating dairy cows. Following a 2-wk covariate period, 48 Holstein cows were blocked based on parity, days in milk, milk yield (MY), and CH4 emission. Cows were randomly assigned to 1 of 2 treatments in an 8-wk randomized complete block design experiment: (1) control corn silage (CON) from an isogenic corn without α-amylase trait and (2) Enogen hybrid corn (Syngenta Seeds LLC) harvested as silage (ECS) containing a bacterial transgene expressing α-amylase (i.e., amylase-enabled) in the endosperm of the grain. The ECS and CON silages were included at 40% of the dietary dry matter (DM) and contained, on average, 43.3 and 41.8% DM and (% DM) 36.7 and 37.5% neutral detergent fiber, and 36.1 and 33.1% starch, respectively. Rumen samples were collected from a subset of 10 cows using the ororuminal sampling technique on wk 3 of the experimental period. Enteric CH4 emission was measured using the GreenFeed system (C-Lock Inc.). Dry matter intake (DMI) was similar between treatments. Compared with CON, MY (38.8 vs. 40.8 kg/d), feed efficiency (1.47 vs. 1.55 kg of MY/kg of DMI), and milk true protein (1.20 vs. 1.25 kg/d) and lactose yields (1.89 vs. 2.00 kg/d) were increased, whereas milk urea nitrogen (14.0 vs. 12.7 mg/dL) was decreased, with the ECS diet. No effect of treatment on energy-corrected MY (ECM) was observed, but a trend was detected for increased ECM feed efficiency (1.45 vs. 1.50 kg of ECM/kg of DMI) for cows fed ECS compared with CON-fed cows. Daily CH4 emission was not affected by treatment, but emission intensity was decreased with the ECS diet (11.1 vs. 10.3 g/kg of milk, CON and ECS, respectively); CH4 emission intensity on ECM basis was not different between treatments. Rumen fermentation, apart from a reduced molar proportion of butyrate in ECS-fed cows, was not affected by treatment. Apparent total-tract digestibility of nutrients and urinary and fecal nitrogen excretions, apart from a trend for increased DM digestibility by ECS-fed cows, were not affected by treatment. Overall, ECS inclusion at 40% of dietary DM increased milk, milk protein, and lactose yields and feed efficiency, and tended to increase ECM feed efficiency but had no effect on ECM yield in dairy cows. The increased MY with ECS led to a decrease in enteric CH4 emission intensity, compared with the control silage.


Assuntos
Rúmen , Silagem , Amilases/metabolismo , Animais , Bovinos , Dieta/veterinária , Digestão , Feminino , Fermentação , Lactação , Metano/metabolismo , Gravidez , Rúmen/metabolismo , Silagem/análise , Zea mays
7.
J Dairy Sci ; 104(9): 9917-9930, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34099295

RESUMO

The objective of this experiment was to determine the effect of increasing digestible His (dHis) levels with a rumen-protected (RP) His product on milk production, milk composition, and plasma AA concentrations in lactating dairy cows fed a metabolizable protein (MP)-deficient diet, according to the National Research Council dairy model from 2001. The companion paper presents results on the effect of increasing dHis dose with a MP-adequate basal diet. Twenty Holstein cows, of which 8 were rumen-cannulated, were used in a replicated 4 × 4 Latin square design experiment with four 28-d periods. Treatments were a control diet supplying 1.8% dHis of MP or 37 g/d (dHis1.8) and the control diet supplemented RP-His to provide 2.2, 2.6, or 3.0%, dHis of MP, or 53, 63, and 74 g/d (dHis2.2, dHis2.6, and dHis3.0, respectively). Histidine dose did not affect dry matter intake, but milk yield increased quadratically and energy-corrected milk yield increased linearly with increasing dHis dose. Histidine dose had a quadratic effect on milk fat concentration but did not affect milk fat yield. Lactose concentration decreased linearly, whereas lactose yield increased linearly with increasing dHis dose. There was a tendency for a linear increase in milk true protein concentration, and milk true protein yield increased linearly with dHis dose. Further, plasma His concentration increased linearly with increasing dHis dose and calculated apparent efficiency of His utilization decreased quadratically with increasing dHis supply. Histidine had minor or no effects on rumen fermentation. In the conditions of this experiment, RP-His supplementation of an MP-deficient corn silage-based diet increased milk yield linearly up to a dHis supply of 63 g/d (or 2.6% dHis of MP) and increased feed efficiency, energy-corrected milk yield and milk true protein yield linearly up to a dHis supply of 74 g/d (or 3.0% dHis of MP) in lactating dairy cows.


Assuntos
Histidina , Lactação , Ração Animal/análise , Animais , Bovinos , Dieta/veterinária , Feminino , Fermentação , Histidina/metabolismo , Leite/metabolismo , Proteínas do Leite/metabolismo , Rúmen/metabolismo
8.
J Dairy Sci ; 104(3): 3052-3066, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33455785

RESUMO

This study investigated the effects of feeding solvent-extracted canola meal (CM), extruded soybean meal (ESBM), or solvent-extracted soybean meal (SSBM) on an equivalent crude protein basis on performance, plasma AA profiles, enteric gas emissions, milk fatty acids, and nutrient digestibility in lactating dairy cows. Fifteen Holstein cows (95 ± 20 d in milk) were used in a replicated 3 × 3 Latin square design experiment with 3 periods of 28 d each. Treatments were 3 diets containing 17.1% CM, 14.2% ESBM, or 13.6% SSBM (dry matter basis). Vegetable oil was added (canola oil for CM or soybean oil for SSBM) to equalize the ether extract concentration of the diets. Rumen-protected Met was supplemented targeting digestible Met supply of 2.2% of metabolizable protein in all diets. Canola meal increased dry matter intake (DMI) by 5.9 and 8.9% in comparison with ESBM and SSBM, respectively. Milk urea nitrogen was lowest in CM, followed by SSBM, and was highest for ESBM. No differences were observed in feed efficiency, energy-corrected milk yield, and milk composition or component yields among treatments. Cows fed CM emitted less enteric CH4 per kg of DMI compared with both ESBM and SSBM, but CH4 emission intensity (CH4 per kg of energy-corrected milk) was similar among treatments. In summary, replacement of ESBM or SSBM with CM, on an equal crude protein basis, in the diet of lactating dairy cows enhanced DMI, but yields of energy-corrected milk and milk components and feed efficiency were similar among treatments.


Assuntos
Glycine max , Lactação , Aminoácidos , Ração Animal/análise , Animais , Bovinos , Dieta/veterinária , Proteínas Alimentares , Feminino , Refeições , Leite , Plasma , Rúmen
9.
J Dairy Sci ; 104(4): 4157-4173, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33516546

RESUMO

Asparagopsis taxiformis (AT) is a source of multiple halogenated compounds and, in a limited number of studies, has been shown to decrease enteric CH4 emission in vitro and in vivo. Similarly, oregano has been suggested as a potential CH4 mitigating agent. This study consisted of 2 in vitro and 2 in vivo experiments. Experiment (Exp.) 1 was aimed at establishing the effect of AT on CH4 emission in vitro. Two experiments (Exp. 2 and 3) with lactating dairy cows were conducted to determine the antimethanogenic effect of AT and oregano (Exp. 3) in vivo. Another experiment (Exp. 4) was designed to investigate stability of bromoform (CHBr3) in AT over time. In Exp. 3, 20 Holstein cows were used in a replicated 4 × 4 Latin square design with four 28-d periods. Treatments were basal diet (control) or basal diet supplemented with (dry matter basis) 0.25% AT (LowAT), 0.50% AT (HighAT), or 1.77% oregano (Origanum vulgare L.) leaves. Enteric gas emissions were measured using the GreenFeed system (C-Lock Inc., Rapid City, SD), and rumen samples were collected for fermentation analysis using the ororuminal technique. In Exp.1 (in vitro), relative to the control, AT (at 1% dry matter basis, inclusion rate) decreased CH4 yield by 98%. In Exp. 3, HighAT decreased average daily CH4 emission and CH4 yield by 65% and 55%, respectively, in experimental periods 1 and 2, but had no effect in periods 3 and 4. The differential response to AT among experimental periods was likely a result of a decrease in CHBr3 concentration in AT over time, as observed in Exp. 4 (up to 84% decrease in 4 mo of storage). In Exp. 3, H2 emission was increased by AT and, as expected, the proportion of acetate in the total volatile fatty acids in the rumen was decreased and those of propionate and butyrate were increased by HighAT compared with the control. Compared with the control, HighAT decreased dry matter intake, milk yield, and energy-corrected milk yield in Exp. 3. Milk composition was not affected by treatment, except lactose percentage and yield were decreased by HighAT. Concentrations of iodine and bromide in milk were increased by HighAT compared with the control. Milk CHBr3 concentration and its organoleptic characteristics were not different between control and HighAT. Oregano had no effect on CH4 emission or lactational performance of the cows in Exp. 3. Overall, AT included at 0.50% in the ration of dairy cows can have a large mitigation effect on enteric CH4 emission, but dry matter intake and milk production may also decrease. There was a marked decrease in the CH4 mitigation potential of AT in the second half of Exp. 3, likely resulting from CHBr3 decay over time.


Assuntos
Origanum , Alga Marinha , Animais , Bovinos , Dieta/veterinária , Feminino , Fermentação , Lactação , Metano/metabolismo , Leite/química , Folhas de Planta/química , Rúmen/metabolismo , Silagem/análise
10.
J Dairy Sci ; 104(1): 357-366, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33131815

RESUMO

This study examined the effect of 3-nitrooxypropanol (3-NOP), an investigational substance, on enteric methane emission, milk production, and composition in Holstein dairy cows. Following a 3-wk covariate period, 48 multi- and primiparous cows averaging (± standard deviation) 118 ± 28 d in milk, 43.4 ± 8 kg/d milk yield, and 594 ± 57 kg of body weight were blocked based on days in milk, milk yield, and enteric methane emission and randomly assigned to 1 of 2 treatment groups: (1) control, no 3-NOP, and (2) 3-NOP applied at 60 mg/kg feed dry matter. Inclusion of 3-NOP was through the total mixed ration and fed for 15 consecutive weeks. Cows were housed in a freestall barn equipped with a Calan Broadbent Feeding System (American Calan Inc., Northwood, NH) for monitoring individual dry matter intake and fed ad libitum once daily. Enteric gaseous emissions (methane, carbon dioxide, and hydrogen) were measured using 3 GreenFeed (C-Lock Inc., Rapid City, SD) units. Dry matter intake, cow body weight, and body weight change were not affected by 3-NOP. Compared with the control group, 3-NOP applied at 60 mg/kg feed dry matter decreased daily methane emission, emission yield, and emission intensity by 26, 27, and 29%, respectively. Enteric emission of carbon dioxide was not affected, and hydrogen emission was increased 6-fold by 3-NOP. Administration of 3-NOP had no effect on milk and energy-corrected milk yields and feed efficiency, increased milk fat and milk urea nitrogen concentrations, and increased milk fat yield but had no other effects on milk components. Concentration of C6:0 and C8:0 and the sum of saturated fatty acids in milk fat were increased by 3-NOP. Total trans fatty acids and the sum of polyunsaturated fatty acids were decreased by 3-NOP. In this experiment, 3-NOP decreased enteric methane daily emission, yield, and intensity without affecting dry matter intake and milk yield, but increased milk fat in high-producing dairy cows.


Assuntos
Bovinos/metabolismo , Trato Gastrointestinal/efeitos dos fármacos , Lactação/efeitos dos fármacos , Metano/metabolismo , Leite/química , Propanóis/administração & dosagem , Animais , Dieta/veterinária , Ácidos Graxos/análise , Feminino , Trato Gastrointestinal/metabolismo , Lipídeos/análise , Leite/efeitos dos fármacos , Nitrogênio/análise
11.
Orthopade ; 48(12): 1042-1044, 2019 Dec.
Artigo em Alemão | MEDLINE | ID: mdl-31620827

RESUMO

Harlequin syndrome is a rare combination of symptoms, characterized by unilateral facial anhidrosis and paleness on the affected side, becoming obvious by contralateral flushing mainly during sports activity. The syndrome is mostly idiopathic, however it is also described as a complication of thoracic surgery, i.e. superior lobectomy. Here, we report on two cases of Harlequin syndrome following scoliosis surgery at the cervicothoracic junction.


Assuntos
Doenças do Sistema Nervoso Autônomo/diagnóstico , Rubor/diagnóstico , Hipo-Hidrose/diagnóstico , Escoliose/cirurgia , Adolescente , Doenças do Sistema Nervoso Autônomo/complicações , Doenças do Sistema Nervoso Autônomo/fisiopatologia , Criança , Rubor/complicações , Rubor/fisiopatologia , Humanos , Hipo-Hidrose/complicações , Hipo-Hidrose/fisiopatologia , Masculino
12.
Transplant Proc ; 50(10): 3082-3087, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30577170

RESUMO

BACKGROUND: The selection of optimal donor is crucial for successful hematopoietic stem cell transplantation (HSCT). Thereby, it is appropriate to know, in addition to basic human leukocyte antigen (HLA) gene matches, other immunogenic or nonimmunogenic parameters predicting the outcome of transplant. OBJECTIVE: A unified approach is necessary to provide a comprehensive view of the patient-donor compatibility characterization outside of standard HLA genes. The approach should be applicable as a tool for optimizing procedures for extended donor typing and/or verification typing of a donor. METHODS: The study used the summary, unification, and innovation of existing practical knowledge and experience of the Czech National Marrow Donor Registry of various factors beyond HLA matching with impact on transplant outcome. RESULTS: An information technology system-implemented procedure (a verification algorithm) is presented as the decision support approach for prematurely discarding less suitable donors from the transplantation process. It is intended primarily for the transplant specialist to help establish optimal procedures for verifying and determining donor critical factors. CONCLUSIONS: A process defining HLAs, killer cell immunoglobulin-like receptors, and cytokine typing strategies was proposed to provide support to a transplant specialist in refining the choice of a suitable donor.


Assuntos
Algoritmos , Sistemas de Apoio a Decisões Clínicas , Seleção do Doador/métodos , Transplante de Células-Tronco Hematopoéticas/métodos , Tchecoslováquia , Antígenos HLA/imunologia , Teste de Histocompatibilidade/métodos , Humanos , Receptores KIR/imunologia , Sistema de Registros
13.
Handb Clin Neurol ; 137: 219-29, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27638073

RESUMO

Sudden unilateral loss of vestibular function is the most severe condition that can occur in the vestibular system. The clinical syndrome is caused by the physiologic properties of the vestibulo-ocular reflex (VOR) arc. In the normal situation, the two peripheral vestibular end organs are connected to a functional unit in coplanar pairs of semicircular canals working in a push-pull mode. "Push-pull" mode means that, when one side is excited, the other side is inhibited, and vice versa due to two mechanisms. First, first-order vestibular afferents are bipolar cells. They have a tonic firing rate that is modulated up or down depending on the direction of rotation. Second, via inhibitory neural connections of second-order vestibular neurons between the vestibular nuclei (vestibular commissural system), the excited side inhibits further the contralateral side. The neural signals are encoded as the difference of the change in firing rate of the vestibular neurons modulating the tonic firing rate on both sides in opposite directions (one side up, the contralateral side down). When the head is not moving, the two peripheral vestibular end organs generate a resting firing rate, which is exactly equal on both sides. When the head is rotated, for example, to the right, the right-sided first-order vestibular afferents increase their discharge rate and the left-sided ones decrease their firing rate. This leads to increase in firing rate of also the type I second-order vestibular neurons in the vestibular nuclei, which synapse with inhibitory type II neurons on the contralateral side, further decreasing the firing rate in the second-order vestibular neurons in the contralateral vestibular nucleus. When the direction of head rotation is reversed, the behavior of the type I neurons on the two sides of the head is reversed. The same relation exists between the coplanar vertical canal afferents on the two sides of the head. When there is unilateral damage to the end organ or the vestibular nerve, the resting firing frequency is drastically reduced or even silenced on the lesioned side, thereby creating a tonic imbalance between the normal resting firing on the healthy side and the lesioned side. This tonic imbalance mimics a permanent rotation toward the healthy side (the side with the higher firing rate), resulting, via the VOR, in a slow-phase drift of the eyes toward the side of the lesion, interrupted by rapid quick-phase resetting eye movements toward the healthy side. This leads to the typical vestibular spontaneous horizontal-torsional nystagmus together with rotational vertigo and postural imbalance, with the tendency to fall toward the lesioned side. The tonic imbalance with the hallmark of spontaneous nystagmus usually recovers within days to weeks after the lesion due to the central restoration of tonic activity on the lesioned side. The dynamic changes, however, might be long-lasting when the peripheral sensors do not recover their function. This causes asymmetric VOR responses, with weaker responses when the head is rotated rapidly toward the lesioned side, leading to transient oscillopsia.


Assuntos
Lateralidade Funcional/fisiologia , Reflexo Vestíbulo-Ocular/fisiologia , Doenças Vestibulares/fisiopatologia , Vestíbulo do Labirinto/fisiopatologia , Doença Aguda , Animais , Movimentos Oculares , Humanos
14.
Nervenarzt ; 85(7): 841-6, 2014 Jul.
Artigo em Alemão | MEDLINE | ID: mdl-24906537

RESUMO

The driving performance of patients with dizziness and vertigo has gained only minor attention so far. Patients with permanent vestibular loss or with episodic vestibular symptoms can experience difficulties in driving a motor vehicle. The presence of a chronic or episodic syndrome presenting with dizziness and/or vertigo does not automatically exclude the ability to drive. Assessment of driving performance should consider the degree of the deficits and compensation in chronic dysfunction and the severity and frequency of attacks, prodromes and triggers of symptoms in episodic disorders.


Assuntos
Exame para Habilitação de Motoristas/legislação & jurisprudência , Técnicas de Diagnóstico Neurológico/normas , Avaliação da Deficiência , Tontura/diagnóstico , Vertigem/diagnóstico , Alemanha , Regulamentação Governamental , Humanos
15.
HNO ; 58(2): 110-2, 114-6, 2010 Feb.
Artigo em Alemão | MEDLINE | ID: mdl-20111915

RESUMO

According to German law granting of driving licenses depends on the proof of an adequate driving capability. The corresponding guidelines are at present in the process of being revised. At the moment bilateral deafness and high-grade hearing loss (> or = 60% in pure tone audiometry) are not exclusion criteria for driving licenses grades A, B and C, while driving licenses grade D and licenses for public transport are generally excluded. In the forthcoming revised edition of the guidelines it has been suggested that the latter group will also not be excluded. The regulations concerning dizziness are wide-sweeping at the moment as no driving license will be granted if dizziness is present but will be more specific in the next issue. In particular a division will be made between single axle and two axle vehicles. An expert assessment about driving suitability can only be made by a certified specialist with qualifications in traffic medicine.


Assuntos
Acidentes de Trânsito/legislação & jurisprudência , Acidentes de Trânsito/prevenção & controle , Exame para Habilitação de Motoristas/legislação & jurisprudência , Surdez/diagnóstico , Tontura/diagnóstico , Prova Pericial/legislação & jurisprudência , Licenciamento/legislação & jurisprudência , Otolaringologia/legislação & jurisprudência , Audiometria de Tons Puros , Surdez/classificação , Avaliação da Deficiência , Tontura/classificação , Definição da Elegibilidade/legislação & jurisprudência , Alemanha , Humanos , Veículos Automotores/classificação , Veículos Automotores/legislação & jurisprudência
16.
Clin Neurophysiol ; 120(3): 632-5, 2009 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-19201647

RESUMO

OBJECTIVE: A characteristic feature of spinocerebellar ataxia type 2 (SCA2) is saccadic slowing at early disease stages. We sought to determine whether this sign is detectable before clinical manifestation and quantifies the disease progression throughout life in linear fashion. METHODS: In a specialized ataxia clinic, 54 presymptomatic carriers of SCA2 polyglutamine expansions and 56 relatives without mutation were documented with regard to their maximal saccade velocity (MSV). RESULTS: Among the control individuals, a significant effect of aging on MSV was observed. After elimination of this age influence through a matched-pair approach, a presymptomatic decrease of MSV could be shown. The MSV reduction was stronger in carriers of large expansions. In the years before calculated disease manifestation, the MSV impairment advanced insidiously. CONCLUSION: Saccade velocity is a sensitive SCA2 endophenotype that reflects early pontine degeneration and may be a useful diagnostic parameter before the onset of ataxia. SIGNIFICANCE: Future neuroprotective therapies of polyglutamine neurodegeneration may be assessed by MSV from earliest to prefinal disease stages.


Assuntos
Transtornos da Motilidade Ocular/etiologia , Transtornos da Motilidade Ocular/fisiopatologia , Músculos Oculomotores/fisiopatologia , Movimentos Sacádicos/fisiologia , Ataxias Espinocerebelares/complicações , Ataxias Espinocerebelares/fisiopatologia , Adolescente , Adulto , Idoso , Ataxinas , Cerebelo/fisiopatologia , Progressão da Doença , Diagnóstico Precoce , Feminino , Heterozigoto , Humanos , Masculino , Pessoa de Meia-Idade , Proteínas do Tecido Nervoso/genética , Vias Neurais/fisiopatologia , Transtornos da Motilidade Ocular/diagnóstico , Músculos Oculomotores/inervação , Valor Preditivo dos Testes , Prognóstico , Ataxias Espinocerebelares/diagnóstico , Adulto Jovem
17.
HNO ; 56(4): 421-4, 2008 Apr.
Artigo em Alemão | MEDLINE | ID: mdl-17333041

RESUMO

The diagnosis and treatment of vertigo are very common in ear nose and throat medicine and neurology. As our case report demonstrates, an interdisciplinary approach is often useful for finding the correct diagnosis. Diagnosing disabling positional vertigo now seems uncomplicated using special MRI. More important is the history of frequent, short-term vertigo, sometimes accompanied by tinnitus. In analogy to trigeminal neuralgia, treatment should be started with carbamazepine or similar drugs. If unsuccessful, microvascular decompression as a neurosurgical intervention is recommended.


Assuntos
Zumbido/diagnóstico , Neuralgia do Trigêmeo/diagnóstico , Vertigem/diagnóstico , Diagnóstico Diferencial , Humanos , Masculino , Pessoa de Meia-Idade , Doenças Raras/diagnóstico , Síndrome
18.
Neurorehabil Neural Repair ; 21(5): 455-9, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-17426347

RESUMO

OBJECTIVES: The effectiveness of 2 different types of gait training in stroke rehabilitation, rhythmic auditory stimulation (RAS) versus neurodevelopmental therapy (NDT)/Bobath- based training, was compared in 2 groups of hemiparetic stroke patients over a 3-week period of daily training (RAS group, n = 43; NDT/Bobath group =35). METHODS: Mean entry date into the study was 21.3 days poststroke for the RAS group and 22.3 days for the control group. Patients entered the study as soon as they were able to complete 5 stride cycles with handheld assistance. Patients were closely equated by age, gender, and lesion site. Motor function in both groups was pre-assessed by the Barthel Index and the Fugl-Meyer Scales. RESULTS: Pre- to posttest measures showed a significant improvement in the RAS group for velocity (P = .006), stride length (P = .0001), cadence (P = .0001) and symmetry (P = .0049) over the NDT/Bobath group. Effect sizes for RAS over NDT/Bobath training were 13.1 m/min for velocity, 0.18 m for stride length, and 19 steps/min for cadence. CONCLUSIONS: The data show that after 3 weeks of gait training, RAS is an effective therapeutic method to enhance gait training in hemiparetic stroke rehabilitation. Gains were significantly higher for RAS compared to NDT/Bobath training.


Assuntos
Estimulação Acústica , Transtornos Neurológicos da Marcha/fisiopatologia , Transtornos Neurológicos da Marcha/reabilitação , Acidente Vascular Cerebral/complicações , Idoso , Idoso de 80 Anos ou mais , Feminino , Transtornos Neurológicos da Marcha/etiologia , Humanos , Masculino , Pessoa de Meia-Idade , Recuperação de Função Fisiológica/fisiologia , Reabilitação/métodos , Método Simples-Cego , Acidente Vascular Cerebral/fisiopatologia , Reabilitação do Acidente Vascular Cerebral , Fatores de Tempo , Resultado do Tratamento
19.
Clin Res Cardiol ; 95 Suppl 1: i59-62, 2006 Jan.
Artigo em Alemão | MEDLINE | ID: mdl-16598550

RESUMO

Diabetes has significant implications for cardiac surgery. It is not only a major risk factor for coronary heart disease but also increases the risk for cerebrovascular complications during heart surgery. Surgical technique is pivotal for the outcome. "Off-pump" surgery carries a lower risk for stroke than conventional heart surgery. When a stroke happens, diabetes plays also a major role for the final outcome. Initial blood glucose levels during a stroke and final outcome are highly correlated. Consequently, patients with ischemic stroke after cardiac surgery should be treated according to the current criteria for stroke treatment. This includes strict monitoring of blood glucose level and avoidance of hypo- as well as hyperglycemia.


Assuntos
Procedimentos Cirúrgicos Cardíacos/efeitos adversos , Transtornos Cerebrovasculares/etiologia , Complicações do Diabetes , Glicemia , Procedimentos Cirúrgicos Cardíacos/métodos , Humanos , Complicações Intraoperatórias , Complicações Pós-Operatórias , Fatores de Risco , Acidente Vascular Cerebral/etiologia
20.
Ann N Y Acad Sci ; 1039: 524-7, 2005 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-15827014

RESUMO

We measured in 82 spinocerebellar ataxia type 2 (SCA2) patients and in 80 controls maximal saccade velocity (MSV) and correlated it to polyglutamine expansion size and disease duration. MSV is strongly decreased in SCA2 patients and is influenced mostly by polyglutamine size.


Assuntos
Transtornos da Motilidade Ocular/fisiopatologia , Movimentos Sacádicos/fisiologia , Ataxias Espinocerebelares/diagnóstico , Adolescente , Adulto , Idade de Início , Idoso , Biomarcadores , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Peptídeos/análise , Fatores de Tempo
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