Live Porcine Research Articles

Differential innate immune responses induced by Mycoplasma hyopneumoniae and Mycoplasma hyorhinis in various types of antigen presenting cells

Mycoplasma (M.) hyopneumoniae is the etiological agent of enzootic pneumonia in pigs and is closely related to M. hyorhinis, which can be isolated from the healthy mucosal surfaces of the upper respiratory tract. In rare cases it can also cause arthritis and polyserositis. Since the innate immune system is an important first line of defense and promotes adaptive immune responses, we characterized the innate immune response of various antigen presenting cells (APCs) to M. hyopneumoniae and M. hyorhinis, which differ in their pathogenicity in vivo. Porcine peripheral blood mononuclear cells were infected with different multiplicities of infection (MOI) of live and inactivated porcine mycoplasmas. Both Mycoplasma species induced strong tumour necrosis factor (TNF) responses in monocytes, with a stronger activation by M. hyorhinis. This higher stimulatory activity was also confirmed for CD40 upregulation. Conventional and plasmacytoid dendritic cells (cDC and pDC, respectively) did not or poorly respond to mycoplasmas in terms of TNF expression but more efficiently in terms of CD40 upregulation. Again, these responses were generally stronger with M. hyorhinis than with M. hyopneumoniae. Both Mycoplasma species also activated B cells in terms of CD25 upregulation, proliferation, and IgM secretion. Interestingly, while the induction of CD25 and in particular proliferation was higher with M. hyorhinis, the IgM secretion did not differ between the two species with the exception of the highest dose of M. hyopneumoniae,which appeared to suppress IgM responses. Taken together, our results provide a comparative analysis of innate immune response with different porcine APCs and demonstrate Mycoplasma species-dependent differences, which could relate to their different pathogenicity in vivo.

Neuroendovascular-specific engineering modifications to the CorPath GRX Robotic System.

The aim of this study was to evaluate new, neuroendovascular-specific engineering and software modifications to the CorPath GRX Robotic System for their ability to support safer and more effective cranial neurovascular interventions in a preclinical model. Active device fixation (ADF) control software, permitting automated manipulation of the guidewire relative to the microcatheter, and a modified drive cassette suitable for neuroendovascular instruments were the respective software and hardware modifications to the current CorPath GRX robot, which was cleared by the FDA for percutaneous coronary and peripheral vascular intervention. The authors then trialed the modified system in a live porcine model with simulated neuroendovascular pathology. Femoral access through the aortic arch to the common carotid artery was accomplished manually (without robotic assistance), and the remaining endovascular procedures were performed with robotic assistance. The system was tested for the enhanced ability to navigate and manipulate neurovascular-specific guidewires and microcatheters. The authors specifically evaluated the movement of the wire forward and backward during the advancement of the microcatheter. Navigation of the rete mirabile and an induced aneurysm within the common carotid artery were successful. The active device fixation feature enabled independent advancement and retraction of the guidewire and working device relative to the microcatheter. When ADF was inactive, the mean forward motion of the guidewire was 5 mm and backward motion was 0 mm. When ADF was active, the mean forward motion of the guidewire was 0 mm and backward motion was 1.5 mm. The modifications made to the robotic cassette enabled the system to successfully manipulate the microcatheter and guidewire safely and in a manner more suited to neuroendovascular procedures than before. There were no occurrences of dissection, extravasation, or thrombosis. The robotic system was originally designed to navigate and manipulate devices for cardiac and peripheral vascular intervention. The current modifications described here improved its utility for the more delicate and tortuous neurovascular environment. This will set the stage for the development of a neurovascular-specific robot.

Re: Robotically-Assisted Sonic Therapy for Renal Ablation in a Live Porcine Model: Initial Preclinical Results.

Re: Robotically-Assisted Sonic Therapy for Renal Ablation in a Live Porcine Model: Initial Preclinical Results.

Using commercial ELISAs to assess humoral response in sows repeatedly vaccinated with modified live porcine reproductive and respiratory syndrome virus

BackgroundSows in breeding herds are often mass vaccinated against porcine reproductive and respiratory syndrome (PRRS) every few months using modified live vaccines (MLV). Field veterinarians repeatedly report that multiple vaccinated...

Live porcine model for surgical training in tracheostomy and open-airway surgery.

To evaluate the validity of a live porcine model for surgical training in tracheostomy and open-airway surgery. Prospective observational study. Eleven expert otolaryngologists-head and neck surgeons rated a live porcine model's realism/anatomical accuracy (face validity) and perceived effectiveness as a training tool (content validity) for tracheostomy and laryngotracheoplasty using anterior costal cartilage and thyroid ala cartilage grafts using a 53-item post-trial questionnaire with a five-point Likert scale. Experts rated the face validity of the live porcine model a median (interquartile range [IQR]) of 4/5 (4-5) and the content validity a median (IQR) of 5/5 (4-5) for each surgical procedure. Overall, 91% strongly agreed or agreed that the simulator would increase trainee competency for tracheostomy and laryngotracheoplasty using costal cartilage graft, and 82% strongly agreed or agreed that it would increase trainee competency for laryngotracheoplasty using thyroid ala cartilage graft. The live porcine model has high face and content validity as a training tool for tracheostomy and laryngotracheoplasty using costal cartilage and thyroid ala cartilage grafts. This training model can help surgical trainees practice these complex, low-frequency procedures. NA Laryngoscope, 130: 2063-2068, 2020.

Maternal viral infection causes global alterations in porcine fetal microglia

Maternal infections during pregnancy are associated with increased risk of neurodevelopmental disorders, although the precise mechanisms remain to be elucidated. Previously, we established a maternal immune activation (MIA) model using swine, which results in altered social behaviors of piglet offspring. These behavioral abnormalities occurred in the absence of microglia priming. Thus, we examined fetal microglial activity during prenatal development in response to maternal infection with live porcine reproductive and respiratory syndrome virus. Fetuses were obtained by cesarean sections performed 7 and 21 d postinoculation (dpi). MIA fetuses had reduced brain weights at 21 dpi compared to controls. Furthermore, MIA microglia increased expression of major histocompatibility complex class II that was coupled with reduced phagocytic and chemotactic activity compared to controls. High-throughput gene-expression analysis of microglial-enriched genes involved in neurodevelopment, the microglia sensome, and inflammation revealed differential regulation in primary microglia and in whole amygdala tissue. Microglia density was increased in the fetal amygdala at 7 dpi. Our data also reveal widespread sexual dimorphisms in microglial gene expression and demonstrate that the consequences of MIA are sex dependent. Overall, these results indicate that fetal microglia are significantly altered by maternal viral infection, presenting a potential mechanism through which MIA impacts prenatal brain development and function.

A pilot study evaluating the utility of a novel tube cricothyrotomy technique in providing ventilation in small animals using a live porcine model.

BackgroundTube cricothyrotomy has been suggested as a first-choice for emergency surgical airway access in small animals, rather than the more commonly accepted procedures of tracheotomy and needle cricothyrotomy.MethodsA small pilot study of tube cricothyrotomy in a live porcine model was conducted to evaluate this method. The technique was modified to permit the use of commonly available equipment and ease of application. Following ethics approval, a tube cricothyrotomy was performed on 9 live pigs. The endpoints were the efficacy of ventilation through the tube as measured by end-tidal carbon dioxide, successful placement of the tube and the time taken for placement.ResultsOf the nine pigs, eight had a tube placed successfully, with the median procedure time being 111.5 seconds (range: 35–240 seconds). After 10 mins, the mean end-tidal carbon dioxide was 58.3 mmHg (95% CI: 55.2–61.3 mmHg), with a range of 54–64 mmHg. Tube cricothyrotomy holds promise as a means of rapidly obtaining tracheal access in small animals and temporarily sustaining ventilation in an emergency.ConclusionFurther detailed investigation is warranted to assess the use of this technique in the small animal emergency setting.

Exploration of peripancreatic lymphatic pathways in a live porcine model

Pancreatic cancer is associated with a poor prognosis, mainly due to lymph node invasion and lymph node recurrence after surgical resection, even after extended lymphadenectomy. The peripancreatic lymphatic system is highly complex and the specific lymphatic drainage of each part of the pancreas has not been established.The aim of this study was to determine the lymphatic drainage pathways specific to each part of the pancreas on live pigs using Patent Blue.The pancreases of 14 live pigs were injected in different parts of the gland. The technique was efficient and reproducible. The diffusion patterns were similar for each location and were reported. Our results in pigs allowed us to define specific nodal relay stations and lymphatic drainage for each part of the pancreas and confirm that independent anatomical-surgical pancreatic segments can be described. It is interesting to note that lymphatic drainage for the upper part of the proximal part of pancreas (duodenal lobe) occurred on the left side of the portal vein. This suggests that lymph node resection during cephalic duodenopancreatectomy in humans should be extended to the left side of the mesenteric vein, and probably to the right side of the superior mesenteric artery, as recently suggested.These results could help surgeons perform safe anatomical-segmental pancreatic resections with accurate lymphadenectomies and improve survival in patients with pancreatic cancer. Based on these results we will perform an innovative prospective study. Patent Blue will be injected into different parts of the gland in patients operated for pancreatic resection, and lymphatic diffusion of the dye will be recorded in relation to their origin from the theoretical pancreatic segments (ClinicalTrials.gov Identifier: NCT03597230).

Teaching in the robotic environment: Use of alternative approaches to guide operative instruction

BackgroundWith the rapid growth of robotic-assisted surgery, surgical educators recognize the need to develop appropriate curriculum for trainees. However, the unique robotic learning environment challenges educators to determine the most appropriate ways to instruct surgical residents. The purpose of this study was to characterize the instructional techniques used in the robotic teaching environment by observing attending surgeon's language and behaviors during resident robotic dissection. Study designAttending robotic surgeons guided senior residents through robotic dissection of live porcine tissue. Three observers documented the language, gestures and behaviors occurring at three different stations, and at a fourth station, they obtained video and audio recordings of the instructional interaction. Afterwards, instructors and residents met in separate focus groups. The authors used qualitative content analysis to summarize the type and frequency of teaching behaviors and focus group information to clarify the analysis. We compared the frequency of the behaviors to an existing taxonomy of 16 operative teaching behaviors in open and laparoscopic surgery. ResultsRobotic instructors used 11 of the 16 behaviors previously described for surgical instruction. Frequency of use differed in the robotic environment due to relevance and application of new techniques. New, unique robotic teaching behaviors involved disengaging the resident from the operative console for either onscreen direction or for gesturing with verbal instruction. Focus group participants highlighted these behaviors as essential. ConclusionRobotic instruction uses a different set of instructional approaches compared to open and laparoscopic surgery. New teaching behaviors emerged driven by physical separation within the robotic environment. Robotic faculty development should emphasize these unique features.

Robotically-Assisted Sonic Therapy for Renal Ablation in a Live Porcine Model: Initial Preclinical Results

PurposeTo demonstrate the feasibility of Robotically Assisted Sonic Therapy (RAST)—a noninvasive and nonthermal focused ultrasound therapy based on histotripsy—for renal ablation in a live porcine model. Materials and MethodsRAST ablations (n = 11) were performed in 7 female swine: 3 evaluated at 1 week (acute) and 4 evaluated at 4 weeks (chronic). Treatment groups were acute bilateral (3 swine, 6 ablations with immediate computed tomography [CT] and sacrifice); chronic single kidney (3 swine, 3 ablations; CT at day 0, week 1, and week 4 after treatment, followed by sacrifice); and chronic bilateral (1 swine, 2 ablations). Treatments were performed using a prototype system (VortxRx; HistoSonics, Inc) and targeted a 2.5-cm-diameter sphere in the lower pole of each kidney, intentionally including the central collecting system. ResultsMean treatment time was 26.4 minutes. Ablations had a mean diameter of 2.4 ± 0.3 cm, volume of 8.5 ± 2.4 cm3, and sphericity index of 1.00. Median ablation volume decreased by 96.1% over 4 weeks. Histology demonstrated complete lysis with residual blood products inside the ablation zone. Temporary collecting system obstruction by thrombus was observed in 4/11 kidneys (2 acute and 2 chronic) and resolved by 1 week. There were no urinary leaks, main vessel thromboses, or adjacent organ injuries on imaging or necropsy. ConclusionsIn this normal porcine model, renal RAST demonstrated complete histologic destruction of the target renal tissue while sparing the urothelium.

A live porcine model for robotic sacrocolpopexy training.

Robotic sacrocolpopexy is an effective and durable technique for pelvic organ prolapse repair. However, the learning curve for this procedure has underscored the need for an effective surgical training module. Given the cost, infection risk, poor tissue compliance, and scarcity of human cadavers, the live porcine model represents a realistic, available, and cost-effective alternative. This article describes a live porcine model for teaching robotic sacrocolpopexy to determine whether it teaches key aspects of live human robotic sacrocolpopexy to the learner. This robotic sacrocolpopexy model was created using the Da Vinci Xi or Si robotic system on domestic pigs under general anesthesia. The main steps of the model include: (1) creating the porcine "cervix" and (2) performing robotic sacrocolpopexy. The model was evaluated with a survey given to 18 board-certified surgeons who attended the training course between December 2016 and April 2018. All of the participants reported improvements in their economy of motion, tissue handling ability, suturing efficiency, and overall performance of robotic sacrocolpopexy. Furthermore, a majority of participants were likely to incorporate aspects of the model into their practice (88.8%) and recommend the model to colleagues (94.2%). The porcine model provides a feasible tool for teaching robotic sacrocolpopexy to physicians.

Lateral thermal spread induced by energy devices: a porcine model to evaluate the influence on the recurrent laryngeal nerve.

Recurrent laryngeal nerve (RLN) paralysis is a frequently observed complication after esophagectomy, and thermal injury is considered to be one of the causes. The difference in the lateral thermal spread associated with the grasping range of various energy devices remains unknown. Ultrasonic devices (Harmonic® HD1000i and Sonicision™) and a vessel-sealing device (Ligasure™) were studied. We evaluated the temperature of these devices, the activation time required, and the thermal spread on porcine muscle when the devices were used with different grasping ranges (thermal spread study). In addition, we evaluated the influence of thermal spread by short grasping use of the energy devices on the viability of RLN in a live porcine model (NIM study). In the thermal spread study, the temperature of the ultrasonic devices lowered as grasping range increased, whereas the highest temperature of Ligasure was observed when used with two-thirds grasping. The activation time of ultrasonic devices became longer as grasping range increased, whereas the grasping range did not influence the activation time of Ligasure. Thermal spreads 1mm from the energy devices were unaffected by the grasping ranges. Although the temperature of the Ligasure was lower than that of the ultrasonic devices, thermal spread by Ligasure was significantly greater than that induced by the ultrasonic devices. In the NIM study, the activation of the Sonicision with one-third grasping range did not cause EMG changes at distances of up to 1mm from the RLN, whereas applying Ligasure with a one-third grasping range 1mm away from the RLN led to a critical result. The grasping range did not influence the thermal spread induced by the energy devices. Ultrasonic devices may be safer in terms of lateral thermal spread to the RLN than Ligasure.

03:09 PM Abstract No. 279 Robotically assisted sonic therapy (RAST) for noninvasive subcutaneous fat ablation in a porcine model

Robotically assisted sonic therapy (RAST) is an ablation modality based on histotripsy, a non-invasive, non-thermal method of focused ultrasound tissue destruction. The purpose of this study was to evaluate the acute and chronic effects of RAST subcutaneous fat ablation in a live porcine model. Five female swine underwent 10 RAST subcutaneous (SQ) fat ablations. The ablations were divided into three groups: acute (n=4, immediate sacrifice), subacute (n=2, sacrifice day 7), and chronic (n=4, sacrifice day 28). RAST was performed with a custom therapy transducer (VortxRx, Histosonics, Inc.) with a prescribed 4.0 x 4.0 x 2.0 cm ovoid ablation zone (prescribed volume=16.8 cm3) targeted to the SQ posterior thoracic fat. Post procedural MRI’s were obtained on Days 7 (n=5) and 28 (n=4) and ablations reviewed for size and appearance. Skin firmness and indentation was rated on a scale of 1-3 during physical examination at day 0, day 7 and day 28 (Firmness Score 1 = no firmness, 2 = mild firmness, 3 = hard; Indentation Score: 1 = no indentation, 2 = mild indentation, 3 = deep indentation). Ablation zones were removed at necropsy and processed for pathologic analysis. All procedures were well-tolerated, with a technical success rate of 9/10. Mean treatment time was 35.5 min. One ablation on a subacute animal was aborted after inadequate anesthesia and intraprocedural movement. At one-week post procedure ablations had a mean volume of 15.7 cm3 (SD ±0.77), and measured 3.9 (0.8), 3.6 (0.1) and 1.9 (0.1) in CC, transverse, and AP dimensions. At four-weeks, volume was 12.9 (SD ±1.3) cm3 (18% decrease) and corresponding lesion measurements were 3.6 (0.1), 3.3 (0.2), and 2.2 (0.1) in CC, transverse, and AP dimensions. The mean Firmness and Indentation scores at physical examination were 0 and 0 at day 0, 7, and 28 with no evidence of injury to the overlying skin. RAST is able to safely and precisely ablate SQ fat in this porcine model. Further work appears warranted, including ablation of mesenteric fat to explore the use of RAST as both a cosmetic and metabolic intervention.

Abstract # 3178 Maternal viral infection causes global changes in fetal microglia and alters gene expression and microglia density in the fetal amygdala

Prenatal exposure to maternal infection increases the risk of neurodevelopmental disorders, though the mechanisms remain to be elucidated. We have previously established a maternal immune activation (MIA) swine model, which results in altered piglet social behaviors postnatally, without microglia activation. Here, we sought to identify microglia activity prenatally, immediately following maternal infection with live porcine reproductive and respiratory syndrome virus (PRRSV). Cesarean sections performed 7 and 21 days post-inoculation (dpi) revealed that MIA fetuses had reduced brain weights and that MIA microglia expressed more of the classical activation marker MHCII and reduced phagocytic and chemotactic activity compared to controls. High-throughput gene expression analysis of microglial-enriched genes revealed differential regulation in primary microglia and in whole amygdala tissue across both time points. Microglia density was increased in the fetal amygdala at 7 but not 21 dpi, though few changes in microglia number and morphology were evident in the fetal hippocampus. Our preliminary data also reveal sexual dimorphisms in gene expression patterns and microglia number and morphology across all time points and tissues, indicating that MIA likely induces dissimilar effects between males and females prenatally. Overall, these data suggest that fetal microglia, particularly in the amygdala, are transiently but significantly altered by maternal viral infection, indicating a potential mechanism through which MIA could negatively impact prenatal neurodevelopment and cause altered behaviors postnatally. Supported by NIH HD069899.

Automated Balloon Control in Resuscitative Endovascular Balloon Occlusion of the Aorta.

The goal of this study was to demonstrate the technical feasibility of automated balloon pressure management during resuscitative endovascular balloon occlusion of the aorta (REBOA) in the pre-clinical setting. This paper presents an intelligent balloon management device which automates the balloon inflation process, preventing the possibility of balloon over or under inflation, optimizes inflation pressure, and if indicated, deflates automating partial REBOA to allow the distal organ perfusion. Edwards TruWave pressure transducers are used to monitor the blood pressure proximal and distal to the balloon, as well as the internal balloon pressure. A faux PID controller, implemented on an Arduino platform, is used in a feedback control loop to allow a user-defined mean arterial pressure setpoint to be reached, via a syringe driver which allows intelligent inflation and deflation of the catheter balloon. Ex vivo testing on a vascular perfusion simulator provided the characteristic behavior of a fully occluded aorta, namely the decrease of distal pressure to zero. In vivo testing on live porcine models indicated that automated partial REBOA is achievable and by enabling partial occlusion may offer improved medical outcomes compared to the manual control. Automated balloon pressure management of endovascular occlusion is feasible and can be successfully implemented without changes on current clinical workflows. With further development, automated balloon management may significantly improve clinical outcomes in REBOA.

Efficacy of a three-day training course in endoscopic submucosal dissection using a live porcine model: a prospective evaluation.

Endoscopic submucosal dissection is currently regarded as the method of choice for the resection of superficial tumours. The objective of our study was to evaluate prospectively the efficiency of an endoscopic submucosal dissection training course using live anaesthetised pigs. Fourteen novice endoscopists participated in three gastric endoscopic submucosal dissection training courses on anaesthetised pigs. Each trainee resected five 'fake' antral lesions. Resected specimen sizes, endoscopic submucosal dissection speeds and the complication rate were evaluated prospectively. Among the 70 procedures performed, 58 could be analysed. There was a strong increase in endoscopic submucosal dissection speed (from 9.7 mm2/minute to 30.4 mm2/minute) during the sessions, marked between the first two endoscopic submucosal dissections compared with the fourth and fifth. There was a significant relation between the surface area of the resected lesion and procedure speed (P < 0.0001). The complication rate was 8.6%. There is a clear benefit from endoscopic submucosal dissection training courses on animal models. Improved endoscopist capability is evident from the third endoscopic submucosal dissection. These data validate the indispensable nature of dedicated training courses and echo the European Society of Gastrointestinal Endoscopy proposition for multistep learning, beginning on animal models.

Evaluating Surgery Resident Technical Skills: Intestinal Anastomosis in a Porcine Model

Because work hour restrictions and technological developments such as staplers change the surgical landscape, efficient resident training methods are necessary to ensure surgical quality. This study evaluates efficacy of a porcine skills laboratory for teaching surgery residents to perform handsewn intestinal anastomoses based on a validated subjective tool and novel objective measurements. We hypothesized that resident performance would improve postintervention; junior residents would improve more than the seniors would. This prospective study was completed over a period of four months in 2015. Participants performed standardized two-layer, handsewn, end-to-end small intestine anastomosis in a live porcine model before (pretest) and after (posttest) an educational intervention. The intervention consisted of an instructional module and skills laboratory teaching session by attending surgeons. Participants were evaluated based on objective measurements of the anastomosis and blinded video evaluations using objective structured assessment of technical skills. Twenty-eight residents in a six-year general surgery program started and completed the study. The objective structured assessment of technical skills ratings demonstrated that the whole resident cohort had statistically significant improvement in pre- to posttest scores, 11.16 to 24.59 (P < 0.001). Junior and senior residents improved independently, 9.59 versus 22.53 (P < 0.001) and 13.59 versus 27.77 (P < 0.001), respectively. Finally, the cohort significantly improved in number of full-thickness Lembert sutures (2.36 vs 0.93, P = 0.001) and time to completion (31.28 vs 28.2 minutes, P = 0.046). Anastomotic leak pressure, anastomotic narrowing, and anastomotic tensile strength all trended toward improvement. A structured educational intervention, teaching intestinal anastomosis in a live porcine model produced significant improvement in residents' technical skills.

Vascular access training for REBOA placement: a feasibility study in a live tissue-simulator hybrid porcine model

BackgroundThe use of resuscitative endovascular balloon occlusion of the aorta (REBOA) in patients with severe haemorrhagic shock is increasing. Obtaining vascular access is a necessary prerequisite for REBOA placement in...

Colorectal endoscopic submucosal dissection using novel articulating devices: a comparative study in a live porcine model.

Colonic endoscopic submucosal dissection (ESD) is time-consuming and bears a high risk of perforation. The aim of the present study was to compare the safety and efficacy between novel articulating devices and conventional ESD in live porcine colon models. Thirty ESDs in ten pigs were carried out at three different locations (15, 25, and 35cm from the anus) by the conventional method (n = 15) and by the new method (n = 15). Procedure times, adverse events (perforation, bleeding), and damage to the muscular layer were recorded, and the ESD time per unit area of the specimens was calculated. The perforation rate using the conventional method was 6.7% (1/15), whereas that using the new method was 0.0%. The number of sites of muscular damage was significantly lower in the new than conventional method (6 vs. 37, respectively; P = 0.024). The mean procedure time was significantly shorter in the new than conventional method (4.6 ± 2.0 vs. 7.0 ± 4.1min/cm2, respectively; P = 0.042). Use of the new ESD method allows for reduced adverse events and a shortened resection time.

An intravascular magnetic wire for the high-throughput retrieval of circulating tumour cells in vivo.

The detection and analysis of rare blood biomarkers is necessary for early diagnosis of cancer and to facilitate the development of tailored therapies. However, current methods for the isolation of circulating tumour cells (CTCs) or nucleic acids present in a standard clinical sample of only 5-10 ml of blood provide inadequate yields for early cancer detection and comprehensive molecular profiling. Here, we report the development of a flexible magnetic wire that can retrieve rare biomarkers from the subject's blood in vivo at a much higher yield. The wire is inserted and removed through a standard intravenous catheter and captures biomarkers that have been previously labelled with injected magnetic particles. In a proof-of-concept experiment in a live porcine model, we demonstrate the in vivo labelling and single-pass capture of viable model CTCs in less than 10 s. The wire achieves capture efficiencies that correspond to enrichments of 10-80 times the amount of CTCs in a 5-ml blood draw, and 500-5,000 times the enrichments achieved using the commercially available Gilupi CellCollector.