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In this paper, we propose ScenThread, a controllable threadlike olfactory display that could be woven into textiles, creating a localized scent release on a flexible surface. ScenThread comprises a tubular PTFE scent reservoir, a lightweight and non-vibrating piezoelectric pumping system for delivering the scents, and a permeable silicone tubing to diffuse the aroma, as well as a heating module using conductive yarns for accelerating the scent release. ScenThread can be refilled and reused multiple times. We articulated the mechanical design of ScenThread and the pattern design of the heating module, smell intensity and multi-scent release. We conducted a preliminary study by testing the scent releasing performance through maximum smell distance and the duration time. We envision that ScenThread could integrate into a wide range of textile-based items in daily life naturally, seamlessly, and artistically.

OBJECTIVES To report the outcomes of antibiotic cement coated interlocking nail (ACCIN) removal, detail a removal technique that mitigates debonding of coating, and describe how to address occurrences intraoperatively. DESIGN Retrospective case series. SETTING Sinai Hospital of Baltimore, Maryland. PATIENTS Twenty-eight patients who underwent ACCIN removal between January 2014 and August 2019. INTERVENTION Removal of ACCINs that were coated using the Silicone tubing method. MAIN OUTCOME MEASUREMENTS Successful removal of the nail with intact antibiotic coating. RESULTS A total of 42 ACCIN removals were included in this study. Successful ACCIN removal was achieved in 37 cases (88.1%), with debonding in only 5 cases (11.9%). Eight nails (19%) required 1 additional removal procedure and 3 nails (7.1 %) required 2 additional removal procedures. The main reasons for the additional procedures were nonunion and persistent infection. CONCLUSIONS ACCIN insertion and removal can be challenging. Proper technique of coating and insertion can facilitate later removal. Removal of knee-long fusion rods can be more challenging. LEVEL OF EVIDENCE Level IV.

Extracorporeal circulation (ECC) is an integral part of cardiac surgery. Yet, the contact with artificial surfaces, mechanical stress, shear, and suction forces within the ECC pose a pronounced risk for damaging the corpuscular components of the blood. These suction forces may be reduced by a repositioning of the roller pumps employed below the reservoir. Furthermore, the repeated compression of the involved silicone tubing is likely to cause degradation. We present our observations regarding changes in the ECC performance following this degradation process. In vitro experiments were performed in a standard as well as a simplified ECC setup and included measurements of pressure, effective flow, and tubing restoring force over a time frame of 12 hours with two different pump positions utilizing transit time flow measurement. Suction forces within the tubing could be significantly reduced by shifting the pump position below the reservoir. Regardless of the setup, the tubing showed significant loss of restoring force as well as effective flow over time. A shift of the pump position within the ECC setup can be recommended to prevent blood damaging negative pressures. Further research is necessary to evaluate the exact cause of the reduction of restoring force overtime as well as its risks for the patients. Finally, our results underline the importance of transit time flow measurements to collect reliable flow data.

To survey the routine application of consumables and sterilized accessories of phacoemulsification in mainland China. This was a cross-sectional questionnaire-based study. A questionnaire link was sent to Chinese ophthalmologists via the most widely used social communication tool (WeChat platform). A total of 815 questionnaires were determined to be valid and were included in the final analysis. The majority of respondents were from Guangdong, Shandong, Zhejiang, Hebei, and Henan provinces. A number of hospitals (48.22%) reused the fluidics management system (FMS) after sterilization. Among the hospitals using disposable FMS, 38.03% reused tubing after sterilization. Most respondents’ hospitals (70.43%) sterilized the handpiece for each operation. Only 38.77% of the respondents’ hospitals adopted irrigation fluid antibiotics and/or intracameral antibiotics intraoperatively. Greater single usage of FMS was significantly associated with higher provincial gross domestic product (GDP), government hospitals, provincial hospitals, and disposable tubing (P

Objective To review the pioneering contributions of Dr. Robert Gibbons of Virginia Mason Medical Center to the evolution and development of the modern ureteral stent. Methods We reviewed Dr. Gibbons' extensive work through primary sources, including interviews, projector slides, radiology images, stent prototypes, his personal writings, and archived documents. In addition, we performed a review of historical texts and manuscripts describing important innovations in the development of the ureteral stent. Results In 1972, motivated by a desire to provide his patients with a long-term alternative to open nephrostomy and inspired by Drs. David Davis and Paul Zimskind, who in 1967 had described the use of indwelling ureteral silicone tubing, Dr. Gibbons began to experiment with modifications to improve upon existing stents. To address distal migration, Dr. Gibbons added “wings” that collapsed as the stent was advanced and expanded once in proper position to secure the stent in place. Barium was embedded into the proximal tip to facilitate radiographic visualization. A flange was added to the distal end, preventing proximal migration and minimizing trigonal irritation, and a tail was attached to aid in stent removal. The result was the original Gibbons stent, the first commercially available ureteral stent, and the establishment of Current Procedural Terminology code 52332, still used today. Conclusion The ureteral stent is a fundamental component of urologic practice. In developing the Gibbons stent, Dr. Gibbons played a pivotal role in addressing the challenge of internal urinary diversion particularly for those who needed long-term management. Urologists and the patients they serve owe Dr. Gibbons and other surgeon-inventors a debt of gratitude for their innovative work.

SummaryAims To design, construct and validate a pharmacokinetics simulator that offers students hands-on opportunities to participate in the design, administration and analysis of oral and intravenous dosing regimens. Methods The Alberta Drug Administration Modeler (ADAM) is a mechanical patient in which peristaltic circulation of water through a network of silicone tubing and glass bottles creates a representation of the outcomes of drug absorption, distribution, metabolism and elimination. Changing peristaltic pump rates and volumes in bottles allows values for pharmacokinetic constants to be varied, thereby simulating differences in drug properties and in patient physiologies and pathologies. Following administration of methylene blue dye by oral or intravenous routes, plasma and/or urine samples are collected and drug concentrations are determined spectrophotometrically. The effectiveness of the simulator in enhancing student competence and confidence was assessed in two undergraduate laboratory classes. Results The simulator effectively models one- and two-compartment drug behaviour in a mathematically-robust and realistic manner. Data allow calculation of numerous pharmacokinetic constants, by traditional graphing methods or with curve-fitting software. Students' competence in solving pharmacokinetic problems involving calculations and graphing improved significantly, while an increase in confidence and understanding was reported. Conclusions The ADAM pharmacokinetics simulator is relatively inexpensive and straightforward to construct, and offers a realistic, hands-on PK learning opportunity for students that effectively complements didactic lectures.

Aim: This study was designed to quantify the influence of blood as test medium compared to water in cannula bench performance assessment. Methods: An in vitro circuit was set-up with silicone tubing between two reservoirs. The test medium was pumped from the lower reservoir by centrifugal pump to the upper reservoir. The test-cannula was inserted in a silicone tube connected between the lower reservoir and the centrifugal pump. Flow rate and pump inlet-pressure were measured for wall-less versus thin-wall cannula using a centrifugal pump in a dynamic bench-test for an afterload of 40-60 mmHg using two media: blood 10 g/dL and 5.6 g/dL and water 0 g/dL. Results: The wall-less cannula showed significantly higher flows rates as compared to the thin-wall cannula (control), with both hemoglobin concentrations and water. Indeed, for a target volume of 200-250 mL of blood (Hg 10 g/dL) in the upper reservoir, the cannula outlet pressure (P) was −14 ± 14 mmHg versus −18 ± 11 mmHg for the wall-less and control respectively; the cannula outlet flow rate (Q) was 3.91 ± 0.41 versus 3.67 ± 0.45 L/min, respectively. At the same target volume but with a Hg of 5.7 g/dL, P was −16 ± 12 mmHg versus −19 ± 12 mmHg and Q was 4 ± 0.1 versus 4 ± 0.4 L/min for the wall-less cannula and control respectively. Likewise, P and Q values with water were −1 mmHg versus −0.67 ± 0.58 mmHg and 4.17 ± 0.45 L/min versus 4.08 ± 0.47 L/min for the wall-less and control respectively. Conclusion: Walls-less cannula showed 5.6% less pump inlet-pressure differences calculated between blood and water, as compared to that of thin-wall cannula (−21 times). Flow differences were 6% and 10% for the walls-less and thin-wall cannula respectively. We conclude that testing the cannula performance with water is a good scenario and can overestimate the flow by a 10%. However, superiority for wall-less is preserved with both water and blood.

Aim The aim of this study was to determine the feasibility and effects of temporary bilateral uterine artery occlusion with silicone tubing on blood loss during vacuum aspiration of cesarean scar pregnancies (CSP). Material and Methods Six patients with CSP underwent removal of gestational masses via vacuum aspiration. At the beginning of the procedure, all patients underwent laparoscopic temporary bilateral uterine artery occlusion with tubing. The main measurements were the operating time, operative blood loss, Doppler examination of the uterine arteries, and complications of procedure. Results The median operation time was 99 min, the median time needed to put the tubing in place (the time from the opening of the retroperitoneum to positioning of the tubing) was 45.5 min and the median time of bilateral uterine artery occlusion with tubing was 32.5 min. The median blood loss was 97.5 mL, and none of the patients required blood transfusion. Doppler examination showed no difference in the pre- and postoperative resistance or pulsatility indices of the uterine vessels. There were no conspicuous complications. The serum s-human chorionic gonadotrophin level decreased to normal within 14–27 days after the operation. Conclusion Laparoscopic temporary bilateral uterine artery occlusion with silicone tubing is an effective, minimally invasive procedure for reducing blood loss during vacuum aspiration in patients with CSP.

Analysis of pharmaceutical compounds in cerebrospinal fluid (CSF) may present challenges due to the combination of the low protein content in this matrix and relatively low drug concentrations, often corresponding to free drug concentrations in plasma, typically found in CSF. A 30% loss of AMG 579 was observed during preparation of quality control samples and further investigation determined that this loss was likely due to binding to collection tubes. This observation also highlighted the possibility of additional losses of AMG 579 that could occur during collection of clinical samples, such as binding to catheters used in the collection of CSF. Loss of AMG 579 in QC samples was reduced from 30% to 5% when the volume of CSF stored in 1.5 mL vials was increased from 0.06 mL to 1 mL. Modest but unavoidable losses of about 20% of AMG 579 were also found following perfusion through both silicone and polypropylene (Pharmed(®) BPT) collection catheters. Silicone tubing was used for CSF collection based on clinical site preference. An LC-MS/MS method was validated to quantify AMG 579 in human CSF to support clinical testing. The original range of the assay was 1-1000 ng/mL but the LLOQ was subsequently lowered to 0.1 ng/mL to better meet project requirements. Interday bias (% RE) and precision (% CV) were -4.2% and 12.3% at the LLOQ, and less than ± 0.9% and 8.3% for higher concentrations, respectively. The compound was stable in human CSF for at least 5h at room temperature, 55 days at -70 °C (-60 to -80 °C range), and through three freeze-thaw cycles. Careful selection of assay conditions and materials minimized losses of the compound during sample collection and storage. While these losses could not be entirely eliminated, practical sample collection and storage conditions were established to allow for analysis of AMG 579 in human clinical trials.

When employed in biomedical applications, the bore of silicone tubing must be modified to become highly lubricious, for example, by means of plasma treatment. In this context, the determination of the degree of lubricity is normally accomplished with the aid of a frictional tribopartner. In practice, this determination is made uncertain and overly lengthy due to running-in behavior. The focus of this investigation is to characterize the running-in behavior, diagnose the factors that contribute to its existence, and develop means by which to eliminate the running-in process. The tribological system that was studied may be categorized as polymer/metal frictional interaction. It was discovered by systematic experimentation that transfer of material, rather than traditional wear, is at the root of the encountered running-in phenomena. These investigations included frictional-based and chemical-detection methodologies. Once the fundamental cause of the running-in behavior had been discovered and confirmed, a method for eliminating running-in was proposed and experimentally validated.

Plant volatiles (PVs) mediate interactions between plants and arthropods, microbes and other plants, and are involved in responses to abiotic stress. PV emissions are therefore influenced by many environmental factors, including herbivore damage, microbial invasion, and cues from neighboring plants, and also light regime, temperature, humidity and nutrient availability. Thus, an understanding of the physiological and ecological functions of PVs must be based on measurements reflecting PV emissions under natural conditions. However, PVs are usually sampled in the artificial environments of laboratories or climate chambers. Sampling of PVs in natural environments is difficult, being limited by the need to transport, maintain and provide power to instruments, or use expensive sorbent devices in replicate. Ideally, PVs should be measured in natural settings with high replication, spatio-temporal resolution and sensitivity, and modest costs. Polydimethylsiloxane (PDMS), a sorbent commonly used for PV sampling, is available as silicone tubing for as little as 0.60 € m(-1) (versus 100-550 € each for standard PDMS sorbent devices). Small pieces of silicone tubing (STs) of various lengths from millimeters to centimeters may be added to any experimental setting and used for headspace sampling, with little manipulation of the organism or headspace. STs have sufficiently fast absorption kinetics and large capacity to sample plant headspaces over a timescale of minutes to hours, and thus can produce biologically meaningful 'snapshots' of PV blends. When combined with thermal desorption coupled to GC-MS (a 40-year-old widely available technology), use of STs yields reproducible, sensitive, spatio-temporally resolved quantitative data from headspace samples taken in natural environments.

Objectives Peristaltic pumps are increasingly employed during fill & finish operations of a biopharmaceutical drug, due to sensitivity of many biological products to rotary piston pump-related stresses. Yet, possibly also unit operations using peristaltic pumps may shed particulates into the final product due to abrasion from the employed tubing. It was the aim of this study to elucidate the potential influence of particles shed from peristaltic pump tubing on the stability of a drug product. Methods Spiking solutions containing shed silicone particles were prepared via peristaltic pumping of placebo under recirculating conditions and subsequently characterized. Two formulated antibodies were spiked with two realistic, but worst-case levels of particles and a 6-month accelerated stability study with storage at 2–8, 25 and 40°C were conducted. Key findings Regarding the formation of aggregates and fragments, both mAbs degraded at their typically expected rates and no additional impact of spiked particles was observed. No changes were discerned however in turbidity, subvisible and visible particle assessments. Flow imaging data for one of the mAb formulations with spiked particles suggested limited colloidal stability of shed particles as indicated by a similar increase in spiked placebo. Conclusions Shed silicone particles from peristaltic pump tubing are assumed to not impair drug product stability.

Objective To evaluate the safety of a novel ureteral occlusion device and compare its performance with that of other devices and guidewires. Methods The XenX (Xenolith Medical) was tested in an ex vivo porcine model to determine the percentage of denuded urothelium because of manipulation within the ureter, the capacity to prevent stone migration during laser lithotripsy, stent compatibility, and the ability to be used for stent placement. Comparative evaluations of the insertion forces and maneuverability were conducted in an in vitro ureter model with the XenX, Stone Cone (Boston Scientific), NTrap (Cook Urological), HiWire (Cook Urological), Roadrunner (Cook Urological), and Sensor (Boston Scientific). Stone migration efficacy was measured using a controlled distribution of stones in 4- and 10-mm silicone tubing with the XenX, NTrap, and Stone Cone. Results The XenX was safely manipulated within the ureter, prevented significant particle migration during laser lithotripsy, and effectively placed stents. The NTrap required the greatest force when attempting to navigate past a stone ( P = .0003), followed by the Stone Cone ( P = .009), with little difference among the other devices ( P > .72). No differences were found for the passing forces ( P = .061), interval to pass ( P = .30), or number of attempts to pass the stone ( P = .68). The XenX prevented stone migration the most, with more notable differences in the 10- than in the 4-mm tubing. Conclusion Ex vivo evaluations hold promise for the XenX to be safely and effectively used during ureteroscopic procedures. Clinical evaluations are warranted to confirm the safety and performance of the XenX relative to the other ureteral occlusion devices.

Widely dehisced abdominal wounds present as challenging surgical cases often incurring multiple complications such as bowel desiccation, perforation, and enterocutaneous fistula [1], equating a mortality of 25% [2]. With the extensive usage of topical negative pressure dressings, these complications have reduced. However these abdomens are now presenting as open wounds with incarcerated edges, necessitating skin grafting on bowel. We present an effective approach to the closure of open abdomens using a combination of topical negative pressure and elastic sutures improvised from silicone tubing. The elastic sutures stretch the skin and prevent wound edges from bedding down prematurely, thereby allowing primary closure.

Background: Plasma/cerebrospinal fluid (CSF) ratio of compound K was determined to be lower than predicted during the conduct of clinical study. This triggered the evaluation of nonspecific binding of drug K and an additional ten compounds in CSF to collection tubing. Physiochemical properties such as pKa and log D values were correlated to the quantified results. Results: Mean recoveries of compound K quality controls sampled within 24 h, as compared with spiked quality control, were 12.9, 44.4 and 77.7% from silicone, Tygon® and Pharmed® collection tubing, respectively. Eight out of ten compounds showed significant loss into silicone and seven out of ten compounds showed no significant loss into Pharmed. Conclusion: Silicone tubing is not recommended and Pharmed appears to be most appropriate. CSF sample collection tubing must be evaluated prior to starting clinical studies.

Purpose: To assess the effectiveness and outcomes of canalicular intubation with the use of a round-tipped, eyed pigtail probe. Methods: Retrospective interventional case series of 228 patients requiring intubation of the canalicular system. Patients were treated surgically with attempted repair of the canalicular system with the round-tipped, eyed pigtail probe. The main outcome measures were successful intubation of the lacrimal system, symptoms of tearing, clinical functional evaluation of lacrimal system, complications, and need for further lacrimal surgery. Results: Of 228 patients, 222 (97.4%) had their canalicular systems successfully intubated with silicone tubing using the round-tipped, eyed pigtail probe. Follow-up was obtained in 191 (86%) of the 222 patients. One-hundred sixty of 191 (83.8%) patients were irrigated and found to be anatomically patent (of the remainder, one was blocked whereas 30 were too young to be irrigated). One hundred fifty-two of the 191 (79.6%) patients had no tearing by history. Thirty-two (16.7%) had occasional tearing on some days that was not bothersome. Seven (3.7%) had intermittent or persistent tearing on a daily basis. Sixty-seven of the 191 (35%) had their lacrimal system more extensively assessed using the dye disappearance test, Jones I test, Jones II test, and canalicular probing. Anatomic patency in this subgroup was demonstrated in 66 of 67 (98.5%) of patients. The dye disappearance test, however, revealed slight asymmetry in 24 of 53 patients (45%) with canalicular lacerations yet only 14 of these 24 (58%) had any symptoms of tearing, indicating some discrepancy between subjective and objective assessment of tearing postcanalicular repair. Fifty-three of the repaired trauma patients underwent probing of the involved and uninvolved canalicular systems. In no patient was a stricture or blockage involving the uninvolved canaliculus identified. Additional lacrimal surgery (dacryocystorhinostomy) was performed on 2 of 191 (1%) patients with greater than 3 months follow-up. Conclusion: The round-tipped, eyed pigtail probe can help safely and effectively identify and repair canalicular lacerations. Symptomatic tearing was infrequent; the lacrimal systems showed complete anatomic patency in the majority of patients tested, and need for further lacrimal surgery was rare following pigtail probe intubation.

Background Endoscopic dacryocystorhinostomy (EN-DCR) is an effective procedure when treating saccal and postsaccal obstructions of the nasolacrimal pathway. The benefit of silicone tubing after DCR is still controversial. We conducted a prospective, randomized study to evaluate the necessity of bicanalicular silicone tubes after primary EN-DCR. Methods Forty-six consecutive primary EN-DCR procedures were performed in 42 patients during 2004-2007. The patients were randomized into two study groups according to whether silicone tubing was used or not. Results The overall success rate after primary EN-DCR was 89%: with silicone tubes it was 78%, and without silicone tubes it was 100%. The difference between these two groups was statistically significant (p < 0.049). The follow-up period was 6 months and included three follow-up visits: 1 week, 2 months, and 6 months postoperatively. If inserted, the silicone tubes were removed at the 2-month visit. Conclusion The results of our prospective, randomized study showed that the use of silicone tubes after primary EN-DCR is not necessary.

Plant volatiles (PVs) mediate manifold interactions between plants and their biotic and abiotic environments (Dicke and Baldwin, 2010; Holopainen and Gershenzon, 2010). An understanding of the physiological and ecological functions of PVs must therefore be based on measurements of PV emissions under natural conditions. Yet sampling PVs in natural environments is difficult, limited by the need to transport, maintain, and power instruments, or else to employ expensive sorbent devices in replicate. Thus PVs are usually measured in the artificial environments of laboratories or climate chambers. However, polydimethysiloxane (PDMS), a sorbent commonly used for PV sampling (Van Pinxteren et al., 2010; Seethapathy and Gorecki, 2012), is available as silicone tubing (ST) for as little as 0.60 €/m (versus 100-550 € apiece for standard PDMS sorbent devices). Small (mm-cm) ST pieces can be placed in any experimental setting and used for headspace sampling with little manipulation of the organism or headspace. ST pieces have absorption kinetics and capacities sufficient to sample plant headspaces on a timescale of minutes to hours, producing biologically meaningful "snapshots" of PV blends. When combined with thermal desorption (TD)-GC-MS analysis - a 40-year-old and widely available technology - ST pieces yield reproducible, sensitive, spatiotemporally resolved, quantitative data from headspace samples taken in natural environments (Kallenbach et al., 2014).

Purpose: To evaluate whether silicone tube insertion is always necessary in external dacryocystorhinostomy (DCR). Methods: During external DCR for primary nasolacrimal duct obstruction carried out between January 2001 and October 2004, silicone intubation was not performed selectively if the lacrimal sac was large and the nasal cavity was not severely narrowed. Results: Of a total of 166 DCR cases in 153 patients, no silicone tube was placed in 74 eyes of 69 patients (44.6%). Anatomic patency of rhinostomy was achieved in all non-intubation group eyes. However, four (6.7%) of these 69 eyes showed persistent epiphora even with anatomic patency. Conclusions: Silicone tubing can be avoided in about 50% of cases of external DCR without detrimentally affecting the success rate. Cases in which intubation was avoided had a large lacrimal sac and a wide nasal cavity.

Background. Shunt infections are one of the major causes of mortality and morbidity of patients with hydrocephalus. The aim of this research is to compare the bacterial colonization characteristics of a regular silicone elastomer shunt material coated with polyvinylpyrrolidone and dimethylpolysiloxane (silicone). Method. Regular coated shunt materials were compared by in-vivo and in-vitro methods. In the in-vitro experiment, silicone and coated material immersed and not immersed in vancomycin solution was treated with a certain concentration of Staphylococcus epidermidis. In the in-vivo study, silicone and coated material specimens were treated with Staphylococcus epidermidis and they were stereotactically placed in the lateral ventricles of the rats. One week after the inoculation, shunt pieces were removed and the colonies were counted by using a scanning electron microscope. Findings. There was a statistically significant difference of colonization in the in-vitro groups in coated material vs. silicone, coated material vs. vancomycin treated silicone, vancomycin treated coated material vs. silicone, vancomycin treated coated material vs. vancomycin treated silicone. There was no statistically significant difference for colonization in in-vitro groups of coated material and vancomycin treated coated material. With in-vivo experiments we can say that, coated material catheters are superior than the silicone catheters in respect to colonization but after the bacterial colonization has occurred, the amount of colonization did not differ. Interpretation. Coated material catheters are superior to silicone catheters and they prevent bacterial colonization in some respect.

We describe an analytical protocol to study biofilms that develop inside silicone tubing of dialysis machines. This protocol has been set up with the help of a dynamic testing device reproducing dialysis conditions. The methodology includes direct microscopic observation, biofilm removal with an original mechanical biofilm scraper, quantitative analysis with culturable and total bacteria counting, and endotoxin level measurement using the LAL chromogenic kinetic assay. The analytical protocol has been assessed on 13 different clinical tubing samples. Most samples were contaminated by adherent cells and the thickest biofilms were found at the connection between the dialysis water distribution loop and the dialysis machine. The less contaminated samples had been removed from dialysis machines that were decontaminated with citric acid and autoclaving, showing the importance of the decontamination procedure for the prevention of biofilm development. This article shows that easy, rapid, reproducible, and economical methods are applicable for a routine analysis of biofilms that develop on dialysis systems and should be included in the regular control of the microbiological quality of dialysis liquids.

Tissue adhesion to bioactive glass-coated silicone tubing in a rat model of peritoneal dialysis catheters and catheter tunnels.BackgroundSilicone peritoneal dialysis catheters do not develop tissue ingrowth, lack a mechanical barrier to periluminal bacterial migration and need cuffs for anchorage. We hypothesized that a bioactive glass coating composed of silicon, calcium, sodium and phosphorous oxides would cause a beneficial tissue reaction causing catheter adhesion, and tested this in a rat model.MethodsA hexane solvent-based method of coating silicone tubes with Bioglass® powder was used, which maintained flexibility, and then the ultrastructure was confirmed with scanning electron microscopy (EM). Segments 2.5 cm were implanted subcutaneously in 8 Sprague-Dawley rats, with uncoated tubes as a contralateral control, and histology was done at 2, 4 and 6 weeks, including special stains and EM.ResultsThe uncoated segments grossly had no adherence to surrounding tissue, and were physically separate from a thin fibrous capsule of approximately 50 μ width. Trichrome stains demonstrated the capsule was rich in collagen. There was minimal adjacent tissue reaction. In contrast, the coated tubes were palpably fixed to the soft tissues, and sections demonstrated an adjacent prominent layer of macrophages and multinucleated giant cells. Small numbers of lymphocytes were noted. This cellular reaction increased over the 6-week implant duration, and was also associated with neovascularization of the tissue adjacent to the segments (33 vessels in coated vs. 20 in controls per ×200 field, P < 0.0001). Many refractile silicone particles and prominent multinucleated giant cells were present, with small numbers of lymphocytes and macrophages. Stains showed scattered discontinuous calcific deposits. These findings are consistent with reports that the Bioglass® silicon oxide leads to the formation of a layer of hydroxyapatite, which binds to collagen and induces a tissue cellular reaction.ConclusionsIn summary, bioactive glass coatings can improve the tissue retention of silicone tubing by promoting adhesion by collagen and cell proliferation, and are promising for future studies of peritoneal dialysis catheters.