The patchy tremor landscape: recent advances in pathophysiology

Item does not contain fulltextPURPOSE OF REVIEW: We focus on new insights in the pathophysiology of Parkinson's disease tremor, essential tremor, tremor in dystonia, and orthostatic tremor. RECENT FINDINGS: Neuroimaging findings suggest that Parkinson's disease resting tremor is associated with dopaminergic dysfunction, serotonergic dysfunction, or both. Not all tremors in Parkinson's disease have the same pathophysiology: postural tremor in Parkinson's disease can be subdivided into pure postural tremor, which involves nondopaminergic mechanisms, and re-emergent tremor, which has a dopaminergic basis. Unlike Parkinson's disease tremor, essential tremor has an electrophysiological signature suggestive of a single (or several tightly coupled) oscillators. Visual feedback increases essential tremor and enhances cerebral activity in the cerebello-thalamo-cortical circuit, supplementary motor area, and parietal cortex. Little is known about dystonic tremor but the available evidence suggests that both the basal ganglia and the cerebellum play a role. Finally, recent work in orthostatic tremor points towards the role of the pontine tegmentum and dysfunctional cerebellar-SMA circuitry. SUMMARY: Many pathological tremors involve the cerebello-thalamo-cortical circuitry, and the clinical and pathophysiological boundaries between tremor disorders are not always clear. Differences between tremor disorders - or even individual patients - may be explained by the specific balance of neurotransmitter degeneration, by distinct circuit dynamics, or by the role of regions interconnected to the cerebello-thalamo-cortical circuit

Effect of supplementing coconut or krabok oil, rich in medium-chain fatty acids on ruminal fermentation, protozoa and archaeal population of bulls

Medium-chain fatty acids (MCFA), for example, capric acid (C10:0), myristic (C14:0) and lauric (C12:0) acid, have been suggested to decrease rumen archaeal abundance and protozoal numbers. This study aimed to compare the effect of MCFA, either supplied through krabok (KO) or coconut (CO) oil, on rumen fermentation, protozoal counts and archaeal abundance, as well as their diversity and functional organization. KO contains similar amounts of C12:0 as CO (420 and 458 g/kg FA, respectively), but has a higher proportion of C14:0 (464 v. 205 g/kg FA, respectively). Treatments contained 35 g supplemental fat per kg DM: a control diet with tallow (T); a diet with supplemental CO; and a diet with supplemental KO. A 4th treatment consisted of a diet with similar amounts of MCFA (i.e. C10:0+C12:0+C14:0) from CO and KO. To ensure isolipidic diets, extra tallow was supplied in the latter treatment (KO+T). Eight fistulated bulls (two bulls per treatment), fed a total mixed ration predominantly based on cassava chips, rice straw, tomato pomace, rice bran and soybean meal (1.5% of BW), were used. Both KO and CO increased the rumen volatile fatty acids, in particular propionate and decreased acetate proportions. Protozoal numbers were reduced through the supplementation of an MCFA source (CO, KO and KO+T), with the strongest reduction by KO. Quantitative real-time polymerase chain reaction assays based on archaeal primers showed a decrease in abundance of Archaea when supplementing with KO and KO+T compared with T and CO. The denaturing gradient gel electrophoresis profiles of the rumen archaeal population did not result in a grouping of treatments. Richness indices were calculated from the number of DGGE bands, whereas community organization was assessed from the Pareto–Lorenz eveness curves on the basis of DGGE band intensities. KO supplementation (KO and KO+T treatments) increased richness and evenness within the archaeal community. Further research including methane measurements and productive animals should elucidate whether KO could be used as a dietary methane mitigation strategy

Coconut and to a lesser extent krabok oil, depress rumen protozoa in beef cows

Krabok and coconut oil were assessed for their ability to affect rumen protozoa via a 3×3 Latin square design experiment with three rumen cannulated beef cows. The diets consisted of a concentrate supplemented with either 25.5 g/kg of tallow (control) or the same quantity of coconut oil or krabok oil. The animals were fed at 1.5% of their body weight per d for 28 d per period. The samples of rumen fluid were collected on day 23 and 27 of each period, 3, 6, 9 and 12h after morning feeding. Rumen protozoa numbers, as well as amylolytic, cellulolytic and proteolytic bacteria were counted microscopically. Fragments of the 18S rRNA gene were amplified in a nested PCR using general eukaryotic and ciliate protozoa-specific primers (Euk1a and 539r followed by 316f- Euk516r-GC). Diversity of the ciliate community was analyzed by Denaturing Gradient Gel Electrophoresis (DGGE) (7% acrylamide, 35-50% gradient; 38 V for 16h at 60 ºC) and gels were processed with BioNumeric software. Protozoa numbers decreased by 0.33 log units in the coconut (P0.10) different between treatments. The propionate proportion was only reduced by supplementation of coconut oil to the TMR. Neither oils affected amylolytic, cellulolytic or proteolytic bacteria counts. Cluster analysis of the DGGE profile showed two clusters of ciliate communities, one including all the T diet-fed animals. All except one DGGE profile of a cow fed the KO diet group into the second cluster. Coconut oil, and to a lesser extent krabok oil, has a marked effect on the numbers of rumen protozoa

Cerebello-Cortical Control of Tremor Rhythm and Amplitude in Parkinson's Disease

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Coconut and to a lesser extent krabok oil, depress rumen protozoa in beef cows

Krabok and coconut oil were assessed for their ability to affect rumen protozoa via a 3×3 Latin square design with three rumen cannulated beef cows. The diets consisted of a TMR supplemented with either 25.5 g/kg of tallow (control) or the same quantity of coconut oil or krabok oil. The animals were fed restricted amounts (DM) of the experimental rations (1.5% of body weight per d) for 28 d per period. The samples of rumen fluid were collected on day 23 and 27 of each period, 0, 3, 6, 9 and 12h after morning feeding. Protozoa numbers decreased by 0.33 log units in the coconut (P0.10) different between treatments. The propionate proportion was only reduced by supplementation of coconut oil to the TMR. Neither oils affected amylolytic, cellulolytic or proteolytic bacteria counts. Cluster analysis of the DGGE profile showed two clusters of ciliate communities, one including all the T diet-fed animals. All except one DGGE profile of a cow fed the KO diet group into the second cluster. Coconut oil, and to a lesser extent krabok oil, has a marked effect on the numbers of rumen protozoa