Incidence of occult cleft palate on prenatal magnetic resonance images obtained for non-cleft indications.

Prenatal diagnosis of craniofacial anomalies has improved family education and preparedness. Isolated cleft palate, however, remains difficult to identify sonographically. The aim of this study was to investigate the rate of incidental cleft palate identified on fetal magnetic resonance imaging (MRI) following the ultrasound detection of non-cleft abnormalities. This was a retrospective study of pregnant women who had fetal MRI performed between 2003 and 2017. To be included, the woman had to have been referred for fetal imaging for a non-cleft indication, with subsequent identification of an isolated cleft palate on MRI. Fetuses with a postnatal diagnosis of Robin sequence were excluded. The study sample included 30 women. Mean gestational age at MRI was 24 weeks 4 days± 38 days. Most referrals (76.7%) were for non-cleft craniofacial anomalies, of which micrognathia was the most common (63.3%). The annual incidence of occult cleft palate diagnosis was 0.4%, and a genetic syndrome was suspected based on imaging findings in 76.7%. Although rare, isolated cleft palate found incidentally on fetal imaging led to concern for a genetic syndrome in a high percentage of cases. This suggests that early referral for fetal MRI may provide critical information when sonographic fetal anomalies have been identified.

Early weight gain in infants with Robin sequence after mandibular distraction.

This retrospective cohort study was performed to assess weight gain in infants with Robin sequence (RS) treated by mandibular distraction osteogenesis (MDO). The primary outcome variable was average daily weight gain for the following time periods: (1) birth to MDO (T1), (2) MDO to distractor removal (T2), (3) distractor removal to 6 months later (T3), and (4) 6 months to 12 months following distractor removal (T4). Published growth curves were used for comparison. Differences were assessed using the Wilcoxon matched-pairs signed rank test. Twenty-two infants were included in the study. During T1, the infants had 9.47 ± 12.61 g/day less weight gain than expected (P = 0.001). However, for T2, T3, and T4, the infants demonstrated 3.48 ± 6.17 g/day (P = 0.028), 2.19 ± 4.47 g/day (P = 0.030), and 1.83 ± 3.25 g/day (P = 0.028) more weight gain than expected. Feeding tube use resulted in improved weight gain during T1 (P < 0.001), but was associated with poorer weight gain in T3 (P = 0.003) and T4 (P = 0.001). In conclusion, infants with RS treated by MDO demonstrated poorer weight gain relative to their peers between birth and the MDO operation. However, from the MDO procedure to 12 months post-distractor removal, infants who had MDO showed faster weight gain than their age-matched peers.

Spatial and Temporal Variation in Soil Nitrous Oxide Emissions from a Rehabilitated and Undisturbed Riparian Forest.

Riparian zones enhance water quality and provide wildlife habitat, but high nutrient input in agricultural landscapes causes nitrous oxide (NO) emissions, potentially negating their benefits of C sequestration. The objectives of this study were to quantify spatiotemporal NO emissions in a rehabilitated and undisturbed natural riparian forest. We also determined soil and vegetation characteristics, and their role in driving spatiotemporal NO emissions. Mean NO-N emissions were not significantly ( < 0.05) different between rehabilitated (7.62 µg m h) and undisturbed (5.93 µg m h) riparian forests. The greatest ( < 0.05) NO-N emissions in both riparian forests were observed during the summer. Soil moisture, temperature, and N were significantly correlated to NO-N emissions. Our results show that soil and vegetation characteristics varied between the two riparian forests, but differences in NO-N emissions were negligible. We also found that NO emissions were influenced by soil characteristics and seasonality, rather than vegetation characteristics or spatial position.

Riparian land-use and rehabilitation: impact on organic matter input and soil respiration.

Rehabilitated riparian zones in agricultural landscapes enhance environmental integrity and provide environmental services such as carbon (C) sequestration. This study quantified differences in organic matter input, soil biochemical characteristics, and soil respiration in a 25-year-old rehabilitated (RH), grass (GRS), and undisturbed natural forest (UNF) riparian zone. Input from herbaceous vegetation was significantly greater (P < 0.05) in the GRS riparian zone, whereas autumnal litterfall was significantly greater (P < 0.05) in the RH riparian zone. Soil bulk density was significantly greater (P < 0.05) in the RH riparian zone, but its soil chemical characteristics were significantly lower. Soil respiration rates were lowest (P < 0.05) in the UNF (106 C m(-2) h(-1)), followed by the RH (169 mg C m(-2) h(-1)) and GRS (194 C m(-2) h(-1)) riparian zones. Soil respiration rates were significantly different (P < 0.05) among seasons, and were significantly correlated with soil moisture (P < 0.05) and soil temperature (P < 0.05) in all riparian zones. Soil potential microbial activity indicated a significantly different (P < 0.05) response of the microbial metabolic diversity in the RH compared to the GRS and UNF riparian zones, and principle component analysis showed a distinct difference in microbial activity among the riparian land-use systems. Rehabilitating degraded riparian zones with trees rather than GRS is a more effective approach to the long-term mitigation of CO2. Therefore, the protection of existing natural/undisturbed riparian forests in agricultural landscapes is equally important as their rehabilitation with trees, given their higher levels of soil organic C and lower soil respiration rates.

Deposition in boreal forests in relation to type, size, number and placement of collectors.

Open precipitation and throughfall was collected at a Norway spruce stand in Finland using funnel-type collectors and at a black spruce stand in Canada using trough-type collectors. The presence or absence of a rim on the funnel, funnel diameter (9, 14 and 20 cm) and length of sampling period (1, 2 and 4 weeks) on monthly values were evaluated at the Norway spruce stand, and the number of collectors required for defined levels of accuracy and precision of throughfall loads to be reached and the influence of the spatial arrangement of collectors on solute concentrations was studied at both stands. The presence of a rim had no significant effect on open precipitation and throughfall amounts, but did on throughfall DOC, Ca(2+), Mg(2+), K(+), Na(+) and Cl(-) ion loads. Deposition loads increased with decreasing funnel diameter; for open precipitation, this was due to increased catch efficiency while for throughfall the increase was attributed to canopy interaction and leaching of litter trapped in the collectors. Calculated monthly H(+) loads decreased and those for all other constituents increased with collection period length. Using 15 collectors at the Norway spruce stand would allow throughfall loads to be determined to within 20% of the true mean weekly value with a confidence level of 95% for most solute, but not for NH(4) (+)-N, NO(3) (-)-N, Mg(2+) and SO(4) (2-)-S. Using 15 trough collectors, the same confidence level at the more heterogeneous black spruce stand would only be achieved for H(+), Cl(-), DOC and SO(4) (2-)-S loads. In both stands, using either random or systematic placements of throughfall collectors gave similar results.

Internal models underlying fingertip force control during object manipulation in humans.

Since sensory information pertaining to an object's weight and weight distribution is not available until after an object has been grasped and lifted from its support surface, skillful manipulation requires predictive scaling of fingertip forces. The predictive control is based on internal models of the object formed during prior manipulatory experience. The present study investigates the extent to which such predictive control achieved with practice of one hand can be generalized to the contralateral hand. Subjects grasped and lifted an object instrumented with force transducers. The object's center of mass (CoM) was displaced 2 cm laterally from the object's center, requiring asymmetric partitioning of tangential force development to prevent tilting. They first performed five lifts using their right hand with the CoM located on a given side with a given weight. Then the subjects translated the object the left side of the body and performed one lift with the left hand. The procedure was repeated five times with the CoM located on each side of the object and with a total object weight of 400 g and 800 g. On the last pre-translation lift, the rate of tangential force development was appropriately higher in the digit opposing the CoM (p<0.05). In contrast, following translation to the left hand, the rate of tangential force development was nearly equal in each digit (p>0.05). Nevertheless the force rates were higher in both digits for lifts with the heavier (800 g) object (p<0.05). The results suggest there is a dichotomy between the generalizability of predictive control based on the object's weight and CoM. We propose that the control may be hierarchical in nature, with parameters that can be globalized representing higher level control and those that cannot (e.g., individuated digit control) representing a lower level control.

A simple model with myofilament compliance predicts activation-dependent crossbridge kinetics in skinned skeletal fibers.

The contribution of thick and thin filaments to skeletal muscle fiber compliance has been shown to be significant. If similar to the compliance of cycling cross-bridges, myofilament compliance could explain the difference in time course of stiffness and force during the rise of tension in a tetanus as well as the difference in Ca(2+) sensitivity of force and stiffness and more rapid phase 2 tension recovery (r) at low Ca(2+) activation. To characterize the contribution of myofilament compliance to sarcomere compliance and isometric force kinetics, the Ca(2+)-activation dependence of sarcomere compliance in single glycerinated rabbit psoas fibers, in the presence of ATP (5.0 mM), was measured using rapid length steps. At steady sarcomere length, the dependence of sarcomere compliance on the level of Ca(2+)-activated force was similar in form to that observed for fibers in rigor where force was varied by changing length. Additionally, the ratio of stiffness/force was elevated at lower force (low [Ca(2+)]) and r was faster, compared with maximum activation. A simple series mechanical model of myofilament and cross-bridge compliance in which only strong cross-bridge binding was activation dependent was used to describe the data. The model fit the data and predicted that the observed activation dependence of r can be explained if myofilament compliance contributes 60-70% of the total fiber compliance, with no requirement that actomyosin kinetics be [Ca(2+)] dependent or that cooperative interactions contribute to strong cross-bridge binding.

Initiation and development of fingertip forces during whole-hand grasping.

The present study examined the initiation of digit contact and fingertip force development during whole-hand grasping. Sixteen healthy subjects grasped an object instrumented with force transducers at each digit and lifted it 10 cm. The grip (normal) and load (tangential) forces and the position of the object were recorded. Twenty-five lifts were performed with various object weights (300 g, 600 g, 900 g) and surface textures (sandpaper and rayon). Despite the large number of degrees of freedom, grip initiation with an object using the whole hand was characterized by stereotypical contact patterns, which are idiosyncratic to each subject across all object weights and textures. However, in spite of the initial asymmetric control, the forces were mainly synchronized by the occurrence of the peak grip and load force rates. The contribution of each digit to the total grip force decreased from radial to ulnar digits. The final force distribution was generally established already at the onset of load forces. Only subtle adjustments were seen thereafter, suggesting a fairly fixed force distribution pattern throughout the grasp. The findings suggest that, despite the large number of degrees of freedom in terms of contact initiation and force distribution in whole-hand grasping: (1) subjects employ preferred movement patterns to establish object contact with their digits, and (2) synchronize the subsequent force development and temporal coordination of the task. Thus while the complexity of the task requires control mechanisms beyond those seen in two-finger precision grasping, there are strategies to simplify the complex task of the initiation and development of fingertip forces in whole-hand grasping.

Objective assessment of progression in Huntington's disease: a 3-year follow-up study.

Objective measures to assess progression of Huntington's disease (HD) are desirable. The authors have previously found that patients with HD with higher Unified Huntington's Disease Rating Scale (UHDRS) motor scores exhibited higher variability of isometric grip forces while grasping an object. Therefore, the authors assessed grip force variability during this task in 10 HD patients with a 3-year follow-up. Grip force variability increased in all patients at the follow-up. Thus, grip force variability during grasping might be an objective and quantitative measure to assess motor deficits associated with the progression of HD.

Contribution of tactile information to accuracy in pointing movements.

We examined the contribution of tactile cues to accuracy during point-to-point movements. We used a task in which the experimenter guided either the left or right hand of the subject to a spatial location during the reference movement. During the subsequent test movement subjects were asked to point with the right hand to the remembered location without vision. Subjects contacted the target with their fingertip either during the reference movement, both the reference and test movements, or neither movement (i.e., the fingertip was held above the target surface). To differentiate between the contribution of tactile and proximal deep pressure information, the left index finger was anesthetized in a subsequent experiment. When subjects contacted the surface with the fingertip of the reference hand alone, error in movement direction decreased. When subjects made fingertip contact during the reference and test movements, gain error also decreased. Anesthesia of the fingertip degraded accuracy, suggesting that tactile information, independent of information from proximal deep pressure receptors, influenced movement accuracy. Thus, tactile information contributed to accuracy in pointing movements. We suggest that forces at fingertip contact may provide information regarding the orientation of the finger and forearm in space, which is used to replicate final arm posture. In addition, tactile cues at the beginning and end of the movement may be used to scale movement amplitude.

Altered movement trajectories and force control during object transport in Huntington's disease.

Individuals with Huntington's Disease (HD) have difficulty grasping and transporting objects, however, the extent to which specific impairments affect their performance is unknown. The present study examined the kinematics and force coordination during transport of an object in 12 subjects with HD and 12 age-matched controls. Subjects grasped an object between their thumb and index finger, transported it 25 cm forward, replaced and released it while their fingertip forces and the object's position were recorded. Five trials were performed with each of three weights (200 g, 400 g, and 800 g). While bradykinesia was evident in subjects with HD, this slowness was not consistently observed in all phases of the movement. The slowness of movement seen during the task appears to be due to impairments in sequencing and the movement strategies selected by the subjects. Compared to control subjects, subjects with HD produced highly curvilinear hand paths and more variable grip forces that were dependent on the weight of the object. Isometric force development and movement speed during transport were unaffected by the disease. The results suggest that prolonged task durations in subjects with HD are not necessarily due to slowness of movement, per se. These findings have clinical implications for understanding the task-specific nature of movement impairments in HD and developing effective intervention strategies.

Skeletal and cardiac muscle contractile activation: tropomyosin "rocks and rolls".

Changes in thin filament structure induced by Ca(2+) binding to troponin and subsequent strong cross-bridge binding regulate additional strong cross-bridge attachment, force development, and dependence of force on sarcomere length in skeletal and cardiac muscle. Variations in activation properties account for functional differences between these muscle types.

Influence of length on force and activation-dependent changes in troponin c structure in skinned cardiac and fast skeletal muscle.

Linear dichroism of 5' tetramethyl-rhodamine (5'ATR) was measured to monitor the effect of sarcomere length (SL) on troponin C (TnC) structure during Ca2+ activation in single glycerinated rabbit psoas fibers and skinned right ventricular trabeculae from rats. Endogenous TnC was extracted, and the preparations were reconstituted with TnC fluorescently labeled with 5'ATR. In skinned psoas fibers reconstituted with sTnC labeled at Cys 98 with 5'ATR, dichroism was maximal during relaxation (pCa 9.2) and was minimal at pCa 4.0. In skinned cardiac trabeculae reconstituted with a mono-cysteine mutant cTnC (cTnC(C84)), dichroism of the 5'ATR probe attached to Cys 84 increased during Ca2+ activation of force. Force and dichroism-[Ca2+] relations were fit with the Hill equation to determine the pCa50 and slope (n). Increasing SL increased the Ca2+ sensitivity of force in both skinned psoas fibers and trabeculae. However, in skinned psoas fibers, neither SL changes or force inhibition had an effect on the Ca2+ sensitivity of dichroism. In contrast, increasing SL increased the Ca2+ sensitivity of both force and dichroism in skinned trabeculae. Furthermore, inhibition of force caused decreased Ca2+ sensitivity of dichroism, decreased dichroism at saturating [Ca2+], and loss of the influence of SL in cardiac muscle. The data indicate that in skeletal fibers SL-dependent shifts in the Ca2+ sensitivity of force are not caused by corresponding changes in Ca2+ binding to TnC and that strong cross-bridge binding has little effect on TnC structure at any SL or level of activation. On the other hand, in cardiac muscle, both force and activation-dependent changes in cTnC structure were influenced by SL. Additionally, the effect of SL on cardiac muscle activation was itself dependent on active, cycling cross-bridges.

Effector-dependent acquisition of novel typing sequences.

In an earlier report we found that when pairs of letters were physically transposed on the keyboard and typists were required to type letters in their new location, the disruptions in typing were reduced when the transpositions involved mirror movements of homologous fingers of the two hands compared with transpositions involving the same hand. We hypothesized that acquisition may be facilitated when a new movement mirrors a previously learned movement. In order to test this hypothesis, in the present study we transposed various pairs of letters between the two hands. Experienced typists (n = 6) typed phrases in which a key was physically transposed with another key on the keyboard and subjects typed the letters in their new location (for 200 trials). The pairs of transpositions involved: (1) similar movements of homologous fingers; (2) different movements of homologous fingers; (3) similar movements of non-homologous fingers; and (4) different movements of non-homologous fingers. After the transposition of keys, there were non-uniform prolongations in the typing intervals of words containing transposed keys, with the largest delay occurring directly before the transposition. Practice had a differential effect on these intervals; some key press intervals achieved control levels, while others did not improve at all. The disruptions in typing were dependent on the specific keys transposed. Transpositions involving non-homologous digits of the two hands were less disruptive than transpositions involving homologous digits. The results do not support our earlier hypothesis that acquisition may be facilitated when a new movement mirrors a previously learned one. These results provide some possible insights into how distinct levels of movement organization develop in typing as a result of practice. Furthermore, the non-uniformity of the typing intervals in the words containing transposed keys supports the notion that typing is organized at multiple levels, including the individual key press and word level.

Ca2+ - and cross-bridge-dependent changes in N- and C-terminal structure of troponin C in rat cardiac muscle.

Linear dichroism of 5'-tetramethylrhodamine (5'ATR)-labeled cardiac troponin C (cTnC) was measured to monitor cTnC structure during Ca2+-activation of force in rat skinned myocardium. Mono-cysteine mutants allowed labeling at Cys-84 (cTnC(C84), near the D/E helix linker); Cys-35 (cTnC(C35), at nonfunctional site I); or near the C-terminus with a cysteine inserted at site 98 (cTnC-C35S,C84S,S98C, cTnC(C98)). With 5'ATR-labeled cTnC(C84) and cTnC(C98) dichroism increased with increasing [Ca2+], while rigor cross-bridges caused dichroism to increase more with 5'ATR-labeled cTnC(C84) than cTnC(C98). The pCa50 values and n(H) from Hill analysis of the Ca2+-dependence of force and dichroism were 6.4 (+/-0.02) and 1.08 (+/-0.04) for force and 6.3 (+/-0.04) and 1.02 (+/-0.09) (n = 5) for dichroism in cTnC(C84) reconstituted trabeculae. Corresponding data from cTnC(C98) reconstituted trabeculae were 5.53 (+/-0.03) and 3.1 (+/-0.17) for force, and 5.39 (+/-0.03) and 1.87 (+/-0.17) (n = 5) for dichroism. The contribution of active cycling cross-bridges to changes in cTnC structure was determined by inhibition of force to 6% of pCa 4.0 controls with 1.0 mM sodium vanadate (Vi). With 5'ATR-labeled cTnC(C84) Vi caused both the pCa50)of dichroism and the maximum value at pCa 4.0 to decrease, while with 5'ATR-labeled cTnC(C98) the pCa50 of dichroism decreased with no change of dichroism at pCa 4.0. The dichroism of 5'ATR-labeled cTnC(C35) was insensitive to either Ca2+ or strong cross-bridges. These data suggest that both Ca2+ and cycling cross-bridges perturb the N-terminal structure of cTnC at Cys-84, while C-terminal structure is altered by site II Ca2+-binding, but not cross-bridges.

Effects of constraint-induced therapy on hand function in children with hemiplegic cerebral palsy.

PURPOSE: The effects of constraint-induced therapy on hand function of the involved upper extremity were examined in three children with hemiplegic cerebral palsy. METHODS: In these case reports, the noninvolved upper extremities of the children were constrained six hours daily for 14 consecutive days. Hand function, strength, sensation, and fingertip force coordination were examined pre- and postintervention. RESULTS: The results indicated that there was an improvement in hand function for two of the three children and an improvement in two-point discrimination threshold values for all children. While there was no consistent change in fingertip force coordination during precision grip across children, one child demonstrated a consistent decrease in duration of temporal phases of fingertip force coordination and two children demonstrated a reorganization of the grip-lift synergy of the involved hand. CONCLUSION AND CLINICAL IMPLICATIONS: Improvement in hand function is not captured by any one measure. The effectiveness of this intervention is promising but may be dependent on the severity of the impairment.