Efficient root metabolism improves drought resistance of Festuca arundinacea.

Festuca arundinacea is a model to work on the mechanisms of drought resistance in grasses. The crucial components of that resistance still remain not fully recognized. It was suggested that deep root system could be a crucial trait for drought avoidance strategy but the other components of root performance under water deficit have not paid much attention of scientists. In this study, two genotypes of F. arundinacea with a different ability to withstand soil water deficit were selected to perform comprehensive research, including analysis of root architecture, phytohormones, proteome, primary metabolome and lipidome under progressive stress conditions, followed by a rewatering period. The experiments were performed in tubes, thus enabling undisturbed development of root systems. We demonstrated that long roots are not sufficient to perfectly avoid drought damage in F. arundinacea and to withstand adverse environmental conditions without a disturbed cellular metabolism (with respect to leaf relative water potential and cellular membrane integrity). Furthermore, we proved that metabolic performance of roots is as crucial as its architecture under water deficit, to cope with drought stress via avoidance, tolerance and regeneration strategies. We believe that the presented studies could be a good reference for the other, more applied experiments, in closely related species.

Alternating hemiplegia of childhood: First South African case report and verapamil as a possible treatment option.

In this case report we describe a child with alternating hemiplegia of childhood, a rare neurodevelopmental disorder, and the effectiveness of an unconventional drug, verapamil, in treating this condition.

Impact of heat stress on estrus expression and follicle size in estrus under field conditions in dairy cows.

The objective of this study was to investigate the impact of heat stress on the expression of estrus signs and follicular diameter at the day of estrus in dairy cows under farm conditions. Cows reported in estrus (i.e., by an automated activity monitoring system or by the herd manager) were examined by a veterinarian. Uterine contractility and the largest diameter of all ovarian structures was determined by transrectal palpation and ultrasonography, respectively. The amount of estrus discharge, mounting traces and the color of the vaginal mucosa were determined in an external examination and scored on 3-point scales. Blood samples were obtained for analysis of serum progesterone concentrations. Cows with a high uterine contractility and high amount of estrus discharge were 4.05 and 1.72 times more likely to have an estrus follicle (large, presumptive preovulatory follicle ≥ 12 mm) than cows expressing low amount of the estrus sign, respectively. The likelihood for a pink vaginal mucosa, clear stringy estrus discharge and mounting traces at the cows back decreased continuously with increasing temperature-humidity index (THI) at the day of estrus. The likelihood for a serum progesterone concentration < 1 ng/ml at the day of estrus decreased continuously with increasing THI ≥74. Follicular size decreased 0.1 mm for each incremental THI point at the day of estrus. The results of this study indicate, that heat stress at the day of estrus significantly reduces the intensity of external estrus signs and the size of estrus follicle decreases with increasing THI.

Evaluation of oestrous detection in dairy cattle comparing an automated activity monitoring system to visual observation.

The objective of the study was to evaluate an automated activity monitoring (AAM) system for oestrous detection in dairy cows. Specifically, we set out to determine the oestrous detection efficiency and accuracy of the AAM system and to compare reproductive performance of cows detected either by AAM, by visual observation (VO) or by at least 1 of the 2 methods (EOM). A total of 1004 potential cow-periods from 348 cows were analysed. Oestrous detection rates (EDR) were calculated for 21 day (VWP+21), 42 day (VWP+42), and 63 day (VWP+63) after voluntary waiting period (VWP). Oestrous detection rate did not differ between AAM (42.1%) and VO (37.3%) during VWP+21 (p > 0.05) but was significantly higher in EOM (56.3%, p < 0.05). Oestrous detection by AAM achieved an efficiency (number of correctly detected oestruses/total number of cow-periods*100) of 35.6% and an accuracy (number of correctly detected oestruses/(number of true+ false oestruses)*100) of 83.8%. Visual observation resulted in an efficiency of 34.3% and accuracy of 75.1%. Pregnancy rate at 200 DIM was higher in AAM (66.8%) and EOM (68.8%) than in VO (57.1%, p < 0.05). Cows detected by AAM (p < 0.05) showed a 1.37 times greater risk to conceive than cows detected by VO as the reference (p < 0.05). The results show that an automated activity monitoring system can support oestrous detection in dairy cattle. The exclusive use of such a system, however, cannot be recommended.

Estrus detection in dairy cattle: changes after the introduction of an automated activity monitoring system?

OBJECTIVE: In context of the study farmers using an automated activity monitoring (AAM) system called Heatime were surveyed on estrus detection practices. The aim of the study was to gain an overview of the usual estrus detection methods and especially to learn about the practical aspects of that system. MATERIAL AND METHODS: Items addressing farm and animal environment, estrus detection before and after installation of Heatime, reproduction, Heatime management and the farmer's perception of efficiency were asked. RESULTS: A total of 232 survey forms were returned (58.3% response rate) and 219 surveys could be used for final analysis. Visual observation was the most common practice to detect estrus. After installation of the Heatime system the farmers assessed that the application of hormones for reproduction management decreased. The majority of the responding dairy farmers (93.1%) strongly agreed or agreed that heat detection was higher after the installation of Heatime. Most of them (92.3%) strongly agreed or agreed with the statement that the reproduction management became easier with Heatime. CONCLUSION: Overall, 94.1% of the responding farm managers were satisfied with the Heatime system and almost all of them (94.5%) would install the system again. CLINICAL RELEVANCE: The results show that the Heatime system is a well accepted estrus detection aid and has the potential to reduce the time needed for estrus detection and might potentially reduce the use of hormones.

Changes in lower extremity muscle function after 56 days of bed rest.

Preservation of muscle function, known to decline in microgravity and simulation (bed rest), is important for successful spaceflight missions. Hence, there is great interest in developing interventions to prevent muscle-function loss. In this study, 20 males underwent 56 days of bed rest. Ten volunteers were randomized to do resistive vibration exercise (RVE). The other 10 served as controls. RVE consisted of muscle contractions against resistance and concurrent whole-body vibration. Main outcome parameters were maximal isometric plantar-flexion force (IPFF), electromyography (EMG)/force ratio, as well as jumping power and height. Measurements were obtained before and after bed rest, including a morning and evening assessment on the first day of recovery from bed rest. IPFF (-17.1%), jumping peak power (-24.1%), and height (-28.5%) declined (P < 0.05) in the control group. There was a trend to EMG/force ratio decrease (-20%; P = 0.051). RVE preserved IPFF and mitigated the decline of countermovement jump performance (peak power -12.2%; height -14.2%). In both groups, IPFF was reduced between the two measurements of the first day of reambulation. This study indicates that bed rest and countermeasure exercises differentially affect the various functions of skeletal muscle. Moreover, the time course during recovery needs to be considered more thoroughly in future studies, as IPFF declined not only with bed rest but also within the first day of reambulation. RVE was effective in maintaining IPFF but only mitigated the decline in jumping performance. More research is needed to develop countermeasures that maintain muscle strength as well as other muscle functions including power.

Bone mass and geometry of the tibia and the radius of master sprinters, middle and long distance runners, race-walkers and sedentary control participants: a pQCT study.

Mechanical loading is thought to be a determinant of bone mass and geometry. Both ground reaction forces and tibial strains increase with running speed. This study investigates the hypothesis that surrogates of bone strength in male and female master sprinters, middle and long distance runners and race-walkers vary according to discipline-specific mechanical loading from sedentary controls. Bone scans were obtained by peripheral Quantitative Computed Tomography (pQCT) from the tibia and from the radius in 106 sprinters, 52 middle distance runners, 93 long distance runners and 49 race-walkers who were competing at master championships, and who were aged between 35 and 94 years. Seventy-five age-matched, sedentary people served as control group. Most athletes of this study had started to practice their athletic discipline after the age of 20, but the current training regime had typically been maintained for more than a decade. As hypothesised, tibia diaphyseal bone mineral content (vBMC), cortical area and polar moment of resistance were largest in sprinters, followed in descending order by middle and long distance runners, race-walkers and controls. When compared to control people, the differences in these measures were always >13% in male and >23% in female sprinters (p<0.001). Similarly, the periosteal circumference in the tibia shaft was larger in male and female sprinters by 4% and 8%, respectively, compared to controls (p<0.001). Epiphyseal group differences were predominantly found for trabecular vBMC in both male and female sprinters, who had 15% and 18% larger values, respectively, than controls (p<0.001). In contrast, a reverse pattern was found for cortical vBMD in the tibia, and only few group differences of lower magnitude were found between athletes and control people for the radius. In conclusion, tibial bone strength indicators seemed to be related to exercise-specific peak forces, whilst cortical density was inversely related to running distance. These results may be explained in two, non-exclusive ways. Firstly, greater skeletal size may allow larger muscle forces and power to be exerted, and thus bias towards engagement in athletics. Secondly, musculoskeletal forces related to running can induce skeletal adaptation and thus enhance bone strength.

Decline of specific peak jumping power with age in master runners.

BACKGROUND: It is difficult to disentangle the effects of pure ageing from those of disuse. Master athletes, however, provide an opportunity to assess the effects of ageing per se, as these people maintain high activity levels during ageing. METHODS: We examined 200 female and 295 male master runners over the age of 35 who participated at European and World master championships. Runners were grouped by short, middle and long distance disciplines. Besides a questionnaire about their sports activities, measurements of counter movement jumps on a ground reaction force plate were performed. Specific peak jump power was the main subject, i.e., maximum jump power per body mass. RESULTS: All discipline groups showed an age-related decline in specific jump power when performing counter movement jumps (p<0.001). Except for female long distance runners, the amount of decline was the same for all discipline groups (p<0.001 to p<0.01) for each gender. The results for female long distance runners was highly spread caused by the small number of participants with older age. CONCLUSIONS: Our data indicate a decline in specific jump power that is similar to that reported in previous studies. The novelty from our results is the comparison of intra-gender decline. We observed the same amount of decline for all runners participating in different running disciplines.

Pulmonary O2 uptake on-kinetics in endurance- and sprint-trained master athletes.

The purpose of this study was to characterise the VO2 kinetic response to moderate intensity cycle exercise in endurance-trained (END) and sprint or power-trained (SPR) track and field master athletes ranging in age from 45 to 85 years. We hypothesised that the time constant (tau) describing the Phase II VO2 on-response would be smaller in the END compared to the SPR athletes, and that the tau would become greater with increasing age in both groups. Eighty-four master athletes who were competing at either the British or European Veteran Athletics Championships acted as subjects, and were classified as either END (800 m - marathon; n = 41), or SPR (100 - 400 m and field events; n = 43) specialists. Subjects completed two 6 minute "step" transitions to a work rate of moderate intensity on a cycle ergometer and pulmonary gas exchange was measured breath-by-breath. Analysis of variance revealed that SPR athletes had slower VO2 on-kinetics (i.e., greater tau) compared to END athletes at each of the age groups studied: 46 - 55 yrs (END: 25 +/- 6 vs. SPR: 36 +/- 9 s; p < 0.10), 56 - 65 yrs (END: 25 +/- 5 vs. SPR: 35 +/- 10 s; p < 0.05), 66 - 75 yrs (END: 29 +/- 10 vs. SPR: 40 +/- 13 s; p < 0.05), and 76 - 85 yrs (END: 31 +/- 10 vs. SPR: 51 +/- 18 s; p < 0.05). The VO2 on-kinetics became slower with advancing age in the SPR athletes (p < 0.05 between 56 - 65 and 76 - 85 yrs) but were not significantly changed in the END athletes. The slower VO2 on-kinetics in SPR compared to END master athletes is consistent both with differences in physiology (e.g., muscle fibre type, oxidative/glycolytic capacity) and training between these specialist athletes. Master END athletes have similar tau values to their younger counterparts (approximately 25 s) suggesting that participation in endurance exercise training limits the slowing of VO2 on-kinetics with age in this population.

Adjusting for the partial volume effect in cortical bone analyses of pQCT images.

Quantitative analyses of computed tomography images are prone to errors due to the partial volume effect which affects objects (e.g., bones) that have a different size or are assessed with different resolution. We have developed a set of equations suitable for both modeling the partial volume effect in cortical bone and for performing the corresponding adjustment. Seven hollow cylinders and 2 cuboid phantoms were made out of Al with 1% Si. The specimens were scanned with a pQCT machine (XCT2002, Stratec Medizintechnik, Pforzheim, Germany) and analyzed with the integrated software, version 5.50. Measurements were performed at different resolutions (voxel size=0.20 to 0.75 mm), both in air and in Ringer solution, and analyses were performed at different detection thresholds. Applying the correcting equations set we could reduce the errors in cortical density by about 80%. The cortical area was assessed with a negligible error at a threshold (theta0) that is equivalent to the mean of the cortical bone density and of the background density. On choosing theta0 as the detection threshold the error in density was lowered to less than 2%. We propose to assess cortical area and cortical density in several steps, first assessing the area and density thereafter. Applying this method should be beneficial whenever "true world" values are required, or objects of different size are compared.

Adult-to-child transmission of tuberculosis: household or community contact?

SETTING: If a child develops tuberculosis, it is assumed that the source was an adult infectious case, usually living in the same house. Restriction fragment length polymorphism (RFLP) was used in this study to establish transmission from source cases to children. DESIGN: Adult and child tuberculosis cases were prospectively identified from 1993 to 1998 and cultures of Mycobacterium tuberculosis collected. Interviews and RFLP analysis of M. tuberculosis strains were performed to establish epidemiological links and to confirm household transmission. RESULTS: Tuberculosis was confirmed by culture in 1139 (91%) of 1291 adults and 65 (16%) of 417 children. Due to problems in recovering specimens or extracting DNA, RFLP analysis was done in 832 adults and 35 children: 19 (54%) children had household members identified with tuberculosis, 12 with the same strain as the child. Twenty-nine (83%) strains from children formed part of community clusters, but definite contact with source cases was established in only 15. CONCLUSION: The presence of an adult with infectious tuberculosis in the same house as a child with tuberculosis does not necessarily imply adult-to-child transmission. Young children may be infected in the community or in the household. These findings have implications for contact tracing and treatment strategies in high incidence areas.

Ivermectin-facilitated immunity in onchocerciasis; activation of parasite-specific Th1-type responses with subclinical Onchocerca volvulus infection.

The present study examined the quantitative and qualitative changes registered in the parasite-specific antibody response, cellular reactivity and cytokine production profile in onchocerciasis patients repeatedly treated with ivermectin over a period of 8 years. The densities of Onchocerca volvulus microfilariae (mf) in treated patients remained significantly reduced, whereas the number of permanently amicrofilaridermic patients (subclinical infection) increased with repeated treatments. In vitro cellular responses to O. volvulus antigen (OvAg) were highest (P < 0.01) in untreated control individuals exposed to infection, but negative for mf of O. volvulus (endemic normals). Cellular reactivity in repeatedly treated patients was higher at 84 than at 36 months post initial treatment (p.i.t); furthermore, the proliferative responses to OvAg, mycobacterial purified protein derivative (PPD) and streptococcal SL-O were greater (P < 0.05) at 84 months p.i.t. in amicrofilaridermic than in microfilaria-positive onchocerciasis patients. In amicrofilaridermic patients such reactivity approached the magnitude observed in endemic normals. Peripheral blood mononuclear cells (PBMC) from patients and endemic normals produced equivalent amounts of IL-2, IL-4 and interferon-gamma (IFN-gamma) in response to mitogenic stimulation with phytohaemagglutinin (PHA); in response to OvAg, however, significantly more IL-2 and IFN-gamma were produced by PBMC from subclinical amicrofilaridermic patients or endemic normals than by mf-positive patients. OvAg-specific production of IL-4 by PBMC from treated patients was lower at 84 than at 36 months p.i.t. At three months p.i.t. the titres of circulating OvAg-specific IgG1-3 had increased (P < 0.05), but they then continuously declined with repeated treatments. Only IgG1 and IgG4 bound to OvAg of mol. wt 2-12 kD at 1 month p.i.t., while recognition of OvAg of mol. wt 10-200 kD by IgG1, IgG2 and IgG4 reached a maximum intensity at 3-6 months p.i.t., with the overall intensity of binding to OvAg gradually weakening thereafter. These results suggest that onchocerciasis-associated immunosuppression is reversible following ivermectin-induced permanent clearance of microfilariae from the skin; and that a vigorous parasite-specific cellular reactivity and a sustained production of IL-2 and IFN-gamma in amicrofilaridermic individuals may contribute to controlling O. volvulus infection.