Adaptive gait responses to varying weight-bearing conditions: Inferences from gait dynamics and H-reflex magnitude.

This study investigates the effects of varying loading conditions on excitability in neural pathways and gait dynamics. We focussed on evaluating the magnitude of the Hoffman reflex (H-reflex), a neurophysiological measure representing the capability to activate motor neurons and the timing and placement of the foot during walking. We hypothesized that weight manipulation would alter H-reflex magnitude, footfall and lower body kinematics. Twenty healthy participants were recruited and subjected to various weight-loading conditions. The H-reflex, evoked by stimulating the tibial nerve, was assessed from the dominant leg during walking. Gait was evaluated under five conditions: body weight, 20% and 40% additional body weight, and 20% and 40% reduced body weight (via a harness). Participants walked barefoot on a treadmill under each condition, and the timing of electrical stimulation was set during the stance phase shortly after the heel strike. Results show that different weight-loading conditions significantly impact the timing and placement of the foot and gait stability. Weight reduction led to a 25% decrease in double limb support time and an 11% narrowing of step width, while weight addition resulted in an increase of 9% in step width compared to body weight condition. Furthermore, swing time variability was higher for both the extreme weight conditions, while the H-reflex reduced to about 45% between the extreme conditions. Finally, the H-reflex showed significant main effects on variability of both stance and swing phases, indicating that muscle-motor excitability might serve as feedback for enhanced regulation of gait dynamics under challenging conditions.

A deep-learning approach for automatically detecting gait-events based on foot-marker kinematics in children with cerebral palsy-Which markers work best for which gait patterns?

Neuromotor pathologies often cause motor deficits and deviations from typical locomotion, reducing the quality of life. Clinical gait analysis is used to effectively classify these motor deficits to gain deeper insights into resulting walking behaviours. To allow the ensemble averaging of spatio-temporal metrics across individuals during walking, gait events, such as initial contact (IC) or toe-off (TO), are extracted through either manual annotation based on video data, or through force thresholds using force plates. This study developed a deep-learning long short-term memory (LSTM) approach to detect IC and TO automatically based on foot-marker kinematics of 363 cerebral palsy subjects (age: 11.8 ± 3.2). These foot-marker kinematics, including 3D positions and velocities of the markers located on the hallux (HLX), calcaneus (HEE), distal second metatarsal (TOE), and proximal fifth metatarsal (PMT5), were extracted retrospectively from standard barefoot gait analysis sessions. Different input combinations of these four foot-markers were evaluated across three gait subgroups (IC with the heel, midfoot, or forefoot). For the overall group, our approach detected 89.7% of ICs within 16ms of the true event with a 18.5% false alarm rate. For TOs, only 71.6% of events were detected with a 33.8% false alarm rate. While the TOE|HEE marker combination performed well across all subgroups for IC detection, optimal performance for TO detection required different input markers per subgroup with performance differences of 5-10%. Thus, deep-learning LSTM based detection of IC events using the TOE|HEE markers offers an automated alternative to avoid operator-dependent and laborious manual annotation, as well as the limited step coverage and inability to measure assisted walking for force plate-based detection of IC events.

Trichosanthes kirilowii Ethanol Extract and Cucurbitacin D Inhibit Cell Growth and Induce Apoptosis through Inhibition of STAT3 Activity in Breast Cancer Cells.

Trichosanthes kirilowii tuber is a traditional medicine which exhibits various medicinal effects including antidiabetic and anticancer activities in several cancer cells. Recently, it was reported that Cucurbitacin D (CuD) isolated from Trichosanthes kirilowii also induces apoptosis in several cancer cells. Constitutive signal transducer and activator of transcription 3 (STAT3), which is an oncogenic transcription factor, is often observed in many human malignant tumor, including breast cancer. In the present study, we tested whether Trichosanthes kirilowii ethanol extract (TKE) or CuD suppresses cell growth and induces apoptosis through inhibition of STAT3 activity in breast cancer cells. We found that both TKE and CuD suppressed proliferation and induced apoptosis and G2/M cell cycle arrest in MDA-MB-231 breast cancer cells by inhibiting STAT3 phosphorylation. In addition, both TKE and CuD inhibited nuclear translocation and transcriptional activity of STAT3. Taken together, our results indicate that TKE and its derived compound, CuD, could be potent therapeutic agents for breast cancer, blocking tumor cell proliferation and inducing apoptosis through suppression of STAT3 activity.

The trajectory of iliac screw in the axial plane in 200 korean patients.

STUDY DESIGN: A retrospective radiographic analysis. PURPOSE: To estimate the accurate trajectory in the axial plane for iliac screw insertion in 200 Korean patients using radiographic images. OVERVIEW OF LITERATURE: Several complications have been encountered after fusion to the lumbosacral junction, including pseudarthrosis, S1 screw loosening, and sacral fractures. Iliac screw fixation is considered an efficient method for augmenting sacral screw fixation but there are few reports on the trajectory of iliac screw insertion. The trajectory in the sagittal plane can be visualized by intraoperative fluoroscopy. However, there is no method to check the accuracy of the trajectory in the axial plane during surgery. METHODS: Between January 2007 and February 2009, 200 patients (107 men and 93 women) who underwent L-spine computed tomography were enrolled in this study. The mean age of the patients was 55.6 +/- 18.3 years (range, 13 to 92 years). The spino-iliac angle (SIA) was measured on the axial image at the S1 level, which was defined as the angle between a vertical line through the center of the spinous process and an oblique line that passed through the center of the outer and inner cortices of the ilium. RESULTS: The group mean SIA was 30.1 degrees +/- 7.8 degrees ; 30.1 degrees +/- 7.7 degrees for men and 29.9 degrees +/- 81.1 degrees for women. There was no significant difference according to gender or age (p > 0.05). CONCLUSIONS: The SIA for the axial trajectory of iliac screws is approximately 30 degrees in Korean patients.

Immunocytochemical localization of zinc transporter 3 in the ependyma of the mouse spinal cord.

We report, for the first time, the light microscopical and ultrastructural appearance of ZnT3-immunoreactivities in the ependymal cells of the central canal of the mouse spinal cord. Light microscopy revealed the presence of ZnT3-immunoreactive (Ir) ependymal cells in 1 microm thick epon sections stained by the ABC method. The ZnT3-Ir cells were observed at all levels of the spinal cord, but were a little more numerous in lumbosacral segments than in cervicothoracic segments. The ZnT3-Ir cells had large, ovoid nuclei with abundant cytoplasm, and protruded into the lumen of the central canal. Our ultrastructural findings suggest that the ZnT3-Ir ependymal cells possess secretory activity directed towards the central canal. We propose that they may play a role in the trans-ependymal mechanism responsible for zinc homeostasis between cerebrospinal fluid and the central area of the gray matter.

Inhibitory zinc-enriched terminals in the mouse cerebellum: double-immunohistochemistry for zinc transporter 3 and glutamate decarboxylase.

In the present study, we showed for the first time the presence of inhibitory zinc-enriched neuron terminals in the mouse cerebellar cortex by means of double-immunohistochemistry for zinc transporter 3 (ZnT3) and glutamate decarboxylase (GAD). The co-localization of ZnT3 and GAD in the cerebellar cortex was analyzed by confocal microscopy. Strong, punctuate ZnT3-immunoreactivity (Ir) was predominantly distributed in the granule cell layer, while GAD-Ir was seen throughout the cerebellar cortical layers. All of the ZnT3-immunoreactive structures were also immunopositive to GAD, but not vice versa. Based on size and position, these double-labeled elements were axonal terminals of the Golgi and basket cells, in the granule cell and molecular layers, respectively. Observations by electron microscopy revealed that ZnT3-immunoreactive terminals showed typical characteristics of the inhibitory synapses like the following: (1) presynaptic terminals containing flat vesicles; and (2) symmetrical synaptic contacts with dendritic elements. The present results indicate that a zinc-containing GABAergic system exists in the mouse cerebellar cortex.