Bringing the Clinic Home: An At-Home Multi-Modal Data Collection Ecosystem to Support Adaptive Deep Brain Stimulation

Adaptive deep brain stimulation (aDBS) shows promise for improving treatment for neurological disorders such as Parkinson's disease (PD). aDBS uses symptom-related biomarkers to adjust stimulation parameters in real-time to target symptoms more precisely. To enable these dynamic adjustments, parameters for an aDBS algorithm must be determined for each individual patient. This requires time-consuming manual tuning by clinical researchers, making it difficult to find an optimal configuration for a single patient or to scale to many patients. Furthermore, the long-term effectiveness of aDBS algorithms configured in-clinic while the patient is at home remains an open question. To implement this therapy at large scale, a methodology to automatically configure aDBS algorithm parameters while remotely monitoring therapy outcomes is needed. In this paper, we share a design for an at-home data collection platform to help the field address both issues. The platform is composed of an integrated hardware and software ecosystem that is open-source and allows for at-home collection of neural, inertial, and multi-camera video data. To ensure privacy for patient-identifiable data, the platform encrypts and transfers data through a virtual private network. The methods include time-aligning data streams and extracting pose estimates from video recordings. To demonstrate the use of this system, we deployed this platform to the home of an individual with PD and collected data during self-guided clinical tasks and periods of free behavior over the course of 1.5 years. Data were recorded at sub-therapeutic, therapeutic, and supra-therapeutic stimulation amplitudes to evaluate motor symptom severity under different therapeutic conditions. These time-aligned data show the platform is capable of synchronized at-home multi-modal data collection for therapeutic evaluation. This system architecture may be used to support automated aDBS research, to collect new datasets and to study the long-term effects of DBS therapy outside the clinic for those suffering from neurological disorders.

Understanding the tool influence function during sub-aperture belt-on-wheel glass polishing

The tool influence function (TIF) during sub-aperture belt-on-wheel polishing has been evaluated as a function of various process conditions (belt use/wear, dwell time, displacement, belt velocity, and wheel modulus and diameter) on fused silica glass workpieces using C e O ₂ polishing media. TIF spots are circular or elliptical in shape with a largely flat bottom character. The volumetric removal rate varies significantly with belt use (or wear), stabilizing after ∼15m i n of use. A modified Preston model, where the pressure dependence is adjusted using a different scaling of the wheel modulus (E w0.5), largely predicts the volumetric removal rate over the range of process conditions evaluated. The relatively high volumetric removal rate of 30-60m m ³/h using a fixed C e O ₂-in-resin-host belt offers a rapid, and hence, more economical, initial polish of aspheric and freeform optics.

Minimizing cotton ball retention in neurological procedures

Neurosurgical operations are long and intensive medical procedures, during which the surgeon must constantly have an unobscured view of the brain in order to be able to properly operate, and thus must use a variety of tools to clear obstructions (like blood and fluid) from the operating area. Currently, cotton balls are the most versatile and effective option to accomplish this as they absorb fluids, are soft enough to safely manipulate the brain, act as a barrier between other tools and the brain, and function as a spacer to keep anatomies of the brain open and visible during the operation. While cotton balls allow neurosurgeons to effectively improve visibility of the operating area, they may also be accidentally left in the brain upon completion of the surgery. This can lead to a wide range of post-operative risks including dangerous immune responses, additional medical care or surgical operations, and even death. This project seeks to develop a unique medical device that utilizes ultrasound technology in order to minimize cotton retention after neurosurgical procedures in order to reduce undesired post-operative risks, and maximize visibility.

Minimizing cotton retention in neurosurgical procedures: which imaging modality can help?

Cotton balls are used in neurosurgical procedures to assist with hemostasis and improve vision within the operative field. Although the surgeon can reshape pieces of cotton for multiple intraoperative uses, this customizability and scale also places them at perpetual risk of being lost, as blood-soaked cotton balls are visually similar to raw brain tissue. Retained surgical cotton can induce potentially life-threatening immunologic responses, impair postoperative imaging, lead to a textiloma or misdiagnosis, and/or require reoperation. This study investigated three imaging modalities (optical, acoustic, and radiographic) to find the most effective method of identifying foreign bodies during neurosurgery. First, we examined the use of dyes to increase contrast between cotton and surrounding parenchyma (optical approach). Second, we explored the ability to distinguish surgical cotton on or below the tissue surface from brain parenchyma using ultrasound imaging (acoustic approach). Lastly, we analyzed the ability of radiography to differentiate between brain parenchyma and cotton. Our preliminary testing demonstrated that dark-colored cotton is significantly more identifiable than white cotton on the surface level. Additional testing revealed that cotton has noticeable different acoustic characteristics (eg, speed of sound, absorption) from neural tissue, allowing for enhanced contrast in applied ultrasound imaging. Radiography, however, did not present sufficient contrast, demanding further examination. These solutions have the potential to significantly reduce the possibility of intraoperative cotton retention both on and below the surface of the brain, while still providing surgeons with traditional cotton material properties without affecting the surgical workflow.

Expression of human activin C protein in insect larvae infected with a recombinant baculovirus

In order to generate dimeric recombinant transforming growth factor-beta (TGF-beta) proteins, expensive eucaryotic cell systems, such as CHO cells, are usually used. An alternative represents the expression of such proteins in insects using a baculovirus expression system. In this study, recombinant human activin C protein was expressed in Noctuidae larvae. On SDS-PAGE, the expressed protein has a size of about 15 kD under reducing conditions and of about 20 kD under non-reducing conditions. This suggests that activin C is expressed as a dimer and disulfide bridges can be formed. Compared with expression in eucaryotic cell culture systems, expression in insect larvae presents a rapid and low cost method, without the need for expensive tissue culture scale-ups or special equipment.

A study of caloric restriction and cardiovascular aging in cynomolgus monkeys (Macaca fascicularis): a potential model for aging research

Caloric restriction has been demonstrated to retard aging processes and extend maximal life span in rodents, and is currently being evaluated in several nonhuman primate trials. We initiated a study in 32 adult cynomolgus monkeys to evaluate the effect of caloric restriction on parameters contributing to atherosclerosis extent. Following pretrial determinations, at which time a baseline measure of ad libitum (ad lib) dietary intake was assessed, animals were randomized to an ad lib fed group (control) or a caloric restriction group (30% reduction from baseline intake). The animals are being evaluated for glycated proteins, insulin, glucose, insulin sensitivity measures, and specific measures of body fat composition by CT scans (e.g., intra-abdominal fat) over specified intervals. The results from the first year of observation demonstrate a significant diet effect on body weight, and specifically intra-abdominal fat. Further, insulin sensitivity has been significantly increased after 1 year of caloric restriction compared to the ad lib fed group. These studies indicate that caloric restriction has a marked effect on a pathologic fat depot, and this change is associated significantly with an improvement in peripheral tissue insulin sensitivity.

Ultrasonographic diagnosis of varicoceles

OBJECTIVE

To assess the ability of color duplex scrotal ultrasonography to detect subclinical varicoceles and confirm the diagnosis of clinical varicoceles.

DESIGN

Physical examination, color duplex scrotal ultrasonography and internal spermatic venography was performed on 64 testicular units in 33 men.

SETTING

Male fertility center.

PATIENTS

Two hundred sixty-two consecutive men being evaluated for male factor infertility of whom 33 agreed to undergo venography.

MAIN OUTCOME MEASURES

Ultrasonographic measurement of scrotal vein diameter of patients in the supine and upright position, before and during valsalva maneuver, and scrotal vein blood flow reversal with valsalva maneuver was compared with the findings of varicocele by physical examination and venography.

RESULTS

The best predictor of a varicocele was internal spermatic vein diameter, and the best overall performance of ultrasonography was achieved with the patient at rest in the supine position. The best cutoff point for venous diameter for a clinical varicocele was 3.6 mm and 2.7 mm for a subclinical varicocele, but the overall accuracy was only 63%.

CONCLUSIONS

Confirmatory studies are needed to support the ultrasonographic diagnosis of varicoceles before considering surgical repair.

Kinesin is bound with high affinity to squid axon organelles that move to the plus-end of microtubules

This paper addresses the question of whether microtubule-directed transport of vesicular organelles depends on the presence of a pool of cytosolic factors, including soluble motor proteins and accessory factors. Earlier studies with squid axon organelles (Schroer et al., 1988) suggested that the presence of cytosol induces a > 20-fold increase in the number of organelles moving per unit time on microtubules in vitro. These earlier studies, however, did not consider that cytosol might nonspecifically increase the numbers of moving organelles, i.e., by blocking adsorption of organelles to the coverglass. Here we report that treatment of the coverglass with casein, in the absence of cytosol, blocks adsorption of organelles to the coverglass and results in vigorous movement of vesicular organelles in the complete absence of soluble proteins. This technical improvement makes it possible, for the first time, to perform quantitative studies of organelle movement in the absence of cytosol. These new studies show that organelle movement activity (numbers of moving organelles/min/micron microtubule) of unextracted organelles is not increased by cytosol. Unextracted organelles move in single directions, approximately two thirds toward the plus-end and one third toward the minus-end of microtubules. Extraction of organelles with 600 mM KI completely inhibits minus-end, but not plus-end directed organelle movement. Upon addition of cytosol, minus-end directed movement of KI organelles is restored, while plus--end directed movement is unaffected. Biochemical studies indicate that KI-extracted organelles attach to microtubules in the presence of AMP-PNP and copurify with tightly bound kinesin. The bound kinesin is not extracted from organelles by 1 M KI, 1 M NaCl or carbonate (pH 11.3). These results suggest that kinesin is irreversibly bound to organelles that move to the plus-end of microtubules and that the presence of soluble kinesin and accessory factors is not required for movement of plus-end organelles in squid axons.

MRI findings of sciatic endometriosis

Endometriosis is a rare cause of sciatic mononeuropathy. We report a woman with cyclic, menstruation-related hip pain associated with right leg weakness and sensory loss. Examination and electrodiagnostic studies suggested sciatic nerve dysfunction. Magnetic resonance imaging (MRI) revealed abnormal signal consistent with endometriotic tissue in the region of the right sciatic nerve. The abnormal signal partially regressed after treatment of the endometriosis. This case further illustrates the utility of MRI in the assessment of rare pelvic disorders.

The abnormal nephrogram

Recognition of qualitative abnormalities in the nephrogram may be as important as the recognition of structural abnormalities for the detection of renal disease.

Directional electron transfer in ruthenium-modified horse heart cytochrome c

Cytochrome c can be modified by [(NH3)5RuII/III-] specifically at the imidazole moiety of histidine 33, and we have recently discussed the thermodynamics and kinetics of electron transfer within this modified protein. X-ray crystal structures of the oxidized and reduced forms of tuna cytochrome c indicate that the separation between the haem group of cytochrome c and the ruthenium label is 12-16 A. Internal electron transfer from the [(NH3)5RuII-] centre to the Fe(III) haem centre occurs with a rate constant k congruent to 53 s-1 (25 degrees C) (delta H = 3.5 kcal mol-1, delta S = -39 EU), as measured by pulse radiolysis. The measured unimolecular rate constant, k congruent to 53 s-1, is on the same timescale as a number of conformational changes that occur within the cytochrome c molecule. These results raise the question of whether electron transfer or protein conformational change is the rate limiting step in this process. We describe here an experiment that probes this intramolecular electron transfer step further. It involves reversing the direction of electron transfer by changing the redox potential of the ruthenium label. Electron transfer in the new ruthenium-cytochrome c derivative described here is from haem(II) to the Ru(III) label, whereas in (NH3)5Ru-cytochrome c the electron transfer is from Ru(II) to haem(III). Intramolecular electron transfer from haem(II) to Ru(III) in the new ruthenium-cytochrome c described here proceeds much slower (greater than 10(5) times) than the electron transfer from Ru(II) to haem(III) in the (NH3)5Ru-cytochrome c. We therefore conclude that electron transfer in cytochrome c is directional, with the protein envelope presumably involved in this directionality.

Structure of an electron transfer complex. II. Chemical modification of carboxyl groups of cytochrome c peroxidase in presence and absence of cytochrome c

Cytochrome c peroxidase forms an electron transfer complex with cytochrome c. The complex is governed by ionic bonds between side chain amino groups of cytochrome c and carboxyl groups of peroxidase. To localize the binding site for cytochrome c on the peroxidase, we have used the method of differential chemical modification. By this method the chemical reactivity of carboxyl groups (toward carbodiimide/aminoethane sulfonate) was compared in free and in complexed peroxidase. When ferricytochrome c was bound to cytochrome c peroxidase, acidic residues 33, 34, 35, 37, 221, 224, and 1 to 3 carboxyls at the C terminus became less reactive by a factor of approximately 4, relative to the remaining 39 carboxylates of peroxidase. Of the less reactive residues those in the 30-40 region and the 221/224 pair are on opposite sides of the surface area which contains the heme propionates. We, therefore, propose that the binding site for cytochrome c on cytochrome c peroxidase spans the area where one heme edge comes close to the molecular surface. The results are in very good agreement with chemical cross-linking studies (Waldmeyer, B., and Bosshard, H.R. (1985) J. Biol. Chem. 260, 5184-5190); they also support a hypothetical model predicted on the basis of the known crystal structures of cytochrome c and peroxidase (Poulos, T.L., and Kraut, J. (1980) J. Biol. Chem. 255, 10322-10330).

Pelvic lipomatosis with ureteral encasement and recurrent thrombophlebitis

Multiple complications occurred in a patient with severe pelvic lipomatosis and recurrent superficial thrombophlebitis. Distal ureteral and rectal encasement by lipomatous infiltration caused obstructive uropathy and rectal deformity without substantial compromise of renal or gastrointestinal function. Clinical evidence suggests an association between pelvic lipomatosis and recurrent superficial thrombophlebitis.

The cytochrome c peroxidase.cytochrome c electron transfer complex. Experimental support of a hypothetical model

A hypothetical model of the cytochrome c peroxidase.cytochrome c complex (Poulos, T. L., and Kraut, J. (1980) J. Biol. Chem. 255, 10322-10330) predicts charge interactions between aspartic acid residues of the peroxidase having a spatial distribution that is complementary to the distribution of essential and highly conserved residues of cytochrome c. In a first attempt to test this model, carboxyl groups of cytochrome c peroxidase have been modified with a water-soluble carbodiimide, either alone or in combination with a nucleophile. Modification led to the loss of up to 90% of the ferrocytochrome c peroxidase activity. At least 4-5 carboxyl groups out of a total of 48, but none of the heme carboxyls, were modified in a derivative with 14% residual activity. In the peroxidase.cytochrome c complex the rate of peroxidase inactivation is slowed and approximately 2 carboxyl groups are protected from chemical modification. In the presence of the carbodiimide, cytochrome c and peroxidase were cross-linked to form a covalent 1:1 complex and the linkage sites were preliminarily characterized. Cross-linking occurred to carboxyl groups of the NH2-terminal fragment 1-119 and of fragment 172-229. The four crucial aspartates of the hypothetical model are located in these same two sequence regions.