Serial Transthoracic Ultrasonography Studies in Hematopoietic Cell Transplant Patients: A Tool for Early Lung Pathology Detection.

Early detection of pulmonary complications can improve outcomes for patients with hematological malignancy (HM). For detecting lung injuries, lung ultrasound (LUS) images have been found to be of greater sensitivity than radiographic images. Our group performed a pilot study of LUS imaging to enhance early detection of pulmonary complications in HM patients. This prospective single-center feasibility study evaluated LUS for detecting pulmonary complications in 18 HM patients enrolled while hospitalized for a hematopoietic cell transplant (HCT) (concurrent-HCT group) or re-hospitalized for complications (post-HCT group). Serial LUS exams were performed and assigned a score from 0 to 5 based on pleural line, B-line, consolidation and pleural effusion features. Correlations between patients' clinical characteristics and LUS features were analyzed. Comparisons between the LUS and radiographic images were evaluated. In the concurrent-HCT patients (79 LUS exams), non-significant fluctuating findings were commonly identified, but one-third of the patients presented pathologic findings (LUS scores ≥ 3). In the post-HCT patients (29 LUS exams), LUS images revealed severe pathologic findings (LUS score = 5) in every patient and, compared with radiographic images, were more sensitive for detecting pleural effusions (p < 0.05). LUS can be routinely performed on hospitalized HM patients, allowing point-of-care early detection of pulmonary complications.

Multipotent Adult Progenitor Cells, but Not Tissue Inhibitor of Matrix Metalloproteinase-3, Increase Tissue Sparing and Reduce Urological Complications following Spinal Cord Injury.

Following spinal cord injury (SCI), inflammation amplifies damage beyond the initial insult, providing an opportunity for targeted treatments. An ideal protective therapy would reduce both edema within the lesion area and the activation/infiltration of detrimental immune cells. Previous investigations demonstrated the efficacy of intravenous injection of multipotent adult progenitor cells (MAPC®) to modulate immune response following SCI, leading to significant improvements in tissue sparing, locomotor and urological functions. Separate studies have demonstrated that tissue inhibitor of matrix metalloproteinase-3 (TIMP3) reduces blood-brain barrier permeability following traumatic brain injury in a mouse model, leading to improved functional recovery. This study examined whether TIMP3, delivered alone or in concert with MAPC cells, improves functional recovery from a contusion SCI in a rat model. The results suggest that intravenous delivery of MAPC cell therapy 1 day following acute SCI significantly improves tissue sparing and impacts functional recovery. TIMP3 treatment provided no significant benefit, and further, when co-administered with MAPC cells, it abrogated the therapeutic effects of MAPC cell therapy. Importantly, this study demonstrated for the first time that acute treatment of SCI with MAPC cells can significantly reduce the incidence of urinary tract infection (UTI) and the use of antibiotics for UTI treatment.

Rapid assay of stem cell functionality and potency using electric cell-substrate impedance sensing.

Regenerative medicine studies using autologous bone marrow mononuclear cells (BM-MNCs) have shown improved clinical outcomes that correlate to in vitro BM-MNC invasive capacity. The current Boyden-chamber assay for testing invasive capacity is labor-intensive, provides only a single time point, and takes 36 hours to collect data and results, which is not practical from a clinical cell delivery perspective. To develop a rapid, sensitive and reproducible invasion assay, we employed Electric Cell-substrate Impedance Sensing (ECIS) technology. Chemokine-directed BM-MNC cell invasion across a Matrigel-coated Transwell filter was measurable within minutes using the ECIS system we developed. This ECIS-Transwell chamber system provides a rapid and sensitive test of stem and progenitor cell invasive capacity for evaluation of stem cell functionality to provide timely clinical data for selection of patients likely to realize clinical benefit in regenerative medicine treatments. This device could also supply robust unambiguous, reproducible and cost effective data as a potency assay for cell product release and regulatory strategies.

Improvement of stability of polidocanol foam for nonsurgical permanent contraception.

BACKGROUND: Polidocanol foam (PF), used clinically as a venous sclerosant, has recently been studied as a safe and inexpensive means for permanent contraception. Delivering the sclerosant to the fallopian tubes as a foam rather than a liquid increases the surface areas and thus enhances the desired epithelial disrupting activity of the agent. However, the foam is inherently unstable and degrades with time. Therefore, increasing foam stability and thus duration of the agent exposure time could increase epithelial effect while allowing reduction in agent concentration and potential toxicity. MATERIALS AND METHODS: We studied methods to improve foam properties that might improve safety and efficacy of PF for intrauterine application. Several types of microporous filters adapted to a syringe-based foaming device were used to study the effect of pore structures on the formation of PF. The foam drainage time and bubble size were characterized. The addition of benzalkonium chloride (BZK) to polidocanol was also investigated for its effects on foam characteristics. RESULTS: A syringe-based foaming device adapted with an inline filter produced smaller bubble PF with a longer foam drainage time. PF generated with a circular pore filter lasts longer than with a noncircular pore filter. The addition of 0.01% of BZK also improved the stability of PF. CONCLUSION: The stability of PF is affected by the pore characteristics of the filter used for foam generation and enhanced by the presence of a small amount of BZK. The improved foam, if shown to be efficacious in animal models of contraception, could lead to a safe, simple and inexpensive method alternative to surgical contraception.

A novel sponge-based wound stasis dressing to treat lethal noncompressible hemorrhage.

BACKGROUND: Noncompressible hemorrhage is the leading cause of preventable death caused by hemorrhage on the battlefield. Currently, there are no hemostatic agents with the ability to control noncompressible hemorrhage. A wound stasis dressing based upon rapidly expanding cellulose minisponges (MS) was developed and tested in a lethal noncompressible model in swine, by fully transecting subclavian artery and vein. MS were compared with conventional hemostasis dressings, Combat Gauze (CG), in a randomized comparison. METHODS: Sixteen 40-kg swine underwent transection of the subclavian artery and vein through a 4.5-cm aperture. After 30-second free bleeding, randomly selected MS or CG (n = 8 per group) were administered by an independent medical officer. The wound cavity was filled with either MS + no external pressure or one CG + one KERLIX gauze with 3 minutes of external pressure. One reapplication was allowed for CG. Mean arterial pressure was maintained at 60 mm Hg with 500-mL Hextend and lactated Ringer's solution intravenously administered up to a maximum of 10-L until study termination at 1 hour. RESULTS: Mean pretreatment blood loss was similar for MS (719 mL) and CG (702 mL). Primary end points, namely, hemostasis at 4 minutes (MS, 75%; CG, 25%; p = 0.13), hemostasis at 60 minutes (MS, 100%; CG, 25%; p = 0.007), and survival at 60 minutes (MS, 100%; CG, 37.5%; p = 0.026), were improved with MS as were secondary end points, namely, total blood loss (MS, 118 mL; CG 1,242 mL; p = 0.021) and length of application time (MS, 25 seconds; CG, 420 seconds; p = 0.004). CONCLUSION: The use of MS is a novel approach for the rapid, simple treatment of severe noncompressible hemorrhage, which provided statistically significant improvement in hemostasis and survival 60 minutes after injury and a large reduction in blood loss, resuscitation fluid requirement, and medic treatment time compared with conventional hemorrhage control dressings in a swine model.

Development of a functional schwann cell phenotype from autologous porcine bone marrow mononuclear cells for nerve repair.

Adult bone marrow mononuclear cells (BM-MNCs) are a potential resource for making Schwann cells to repair damaged peripheral nerves. However, many methods of producing Schwann-like cells can be laborious with the cells lacking a functional phenotype. The objective of this study was to develop a simple and rapid method using autologous BM-MNCs to produce a phenotypic and functional Schwann-like cell. Adult porcine bone marrow was collected and enriched for BM-MNCs using a SEPAX device, then cells cultured in Neurobasal media, 4 mM L-glutamine and 20% serum. After 6-8 days, the cultures expressed Schwann cell markers, S-100, O4, GFAP, were FluoroMyelin positive, but had low p75(NGF) expression. Addition of neuregulin (1-25 nM) increased p75(NGF) levels at 24-48 hrs. We found ATP dose-dependently increased intracellular calcium [Ca(2+)](i), with nucleotide potency being UTP = ATP > ADP > AMP > adenosine. Suramin blocked the ATP-induced [Ca(2+)](i) but α, ß,-methylene-ATP had little effect suggesting an ATP purinergic P2Y2 G-protein-coupled receptor is present. Both the Schwann cell markers and ATP-induced [Ca(2+)](i) sensitivity decreased in cells passaged >20 times. Our studies indicate that autologous BM-MNCs can be induced to form a phenotypic and functional Schwann-like cell which could be used for peripheral nerve repair.

Structural and cellular characterization of electrospun recombinant human tropoelastin biomaterials.

An off-the-shelf vascular graft biomaterial for vascular bypass surgeries is an unmet clinical need. The vascular biomaterial must support cell growth, be non-thrombogenic, minimize intimal hyperplasia, match the structural properties of native vessels, and allow for regeneration of arterial tissue. Electrospun recombinant human tropoelastin (rTE) as a medial component of a vascular graft scaffold was investigated in this study by evaluating its structural properties, as well as its ability to support primary smooth muscle cell adhesion and growth. rTE solutions of 9, 15, and 20 wt% were electrospun into sheets with average fiber diameters of 167 ± 32, 522 ± 67, and 735 ± 270 nm, and average pore sizes of 0.4 ± 0.1, 5.8 ± 4.3, and 4.9 ± 2.4 µm, respectively. Electrospun rTE fibers were cross-linked with disuccinimidyl suberate to produce an insoluble fibrous polymeric recombinant tropoelastin (prTE) biomaterial. Smooth muscle cells attached via integrin binding to the rTE coatings and proliferated on prTE biomaterials at a comparable rate to growth on prTE coated glass, glass alone, and tissue culture plastic. Electrospun tropoelastin demonstrated the cell compatibility and design flexibility required of a graft biomaterial for vascular applications.

Mechanical property characterization of electrospun recombinant human tropoelastin for vascular graft biomaterials.

The development of vascular grafts has focused on finding a biomaterial that is non-thrombogenic, minimizes intimal hyperplasia, matches the mechanical properties of native vessels and allows for regeneration of arterial tissue. In this study, the structural and mechanical properties and the vascular cell compatibility of electrospun recombinant human tropoelastin (rTE) were evaluated as a potential vascular graft support matrix. Disuccinimidyl suberate (DSS) was used to cross-link electrospun rTE fibers to produce a polymeric recombinant tropoelastin (prTE) matrix that is stable in aqueous environments. Tubular 1cm diameter prTE samples were constructed for uniaxial tensile testing and 4mm small-diameter prTE tubular scaffolds were produced for burst pressure and cell compatibility evaluations from 15 wt.% rTE solutions. Uniaxial tensile tests demonstrated an average ultimate tensile strength (UTS) of 0.36±0.05 MPa and elastic moduli of 0.15±0.04 and 0.91±0.16 MPa, which were comparable to extracted native elastin. Burst pressures of 485±25 mm Hg were obtained from 4mm internal diameter scaffolds with 453±74 µm average wall thickness. prTE supported endothelial cell growth with typical endothelial cell cobblestone morphology after 48 h in culture. Cross-linked electrospun rTE has promising properties for utilization as a vascular graft biomaterial with customizable dimensions, a compliant matrix and vascular cell compatibility.

Exhaustive expansion: A novel technique for analyzing complex data generated by higher-order polychromatic flow cytometry experiments.

BACKGROUND: The complex data sets generated by higher-order polychromatic flow cytometry experiments are a challenge to analyze. Here we describe Exhaustive Expansion, a data analysis approach for deriving hundreds to thousands of cell phenotypes from raw data, and for interrogating these phenotypes to identify populations of biological interest given the experimental context. METHODS: We apply this approach to two studies, illustrating its broad applicability. The first examines the longitudinal changes in circulating human memory T cell populations within individual patients in response to a melanoma peptide (gp100209-2M) cancer vaccine, using 5 monoclonal antibodies (mAbs) to delineate subpopulations of viable, gp100-specific, CD8+ T cells. The second study measures the mobilization of stem cells in porcine bone marrow that may be associated with wound healing, and uses 5 different staining panels consisting of 8 mAbs each. RESULTS: In the first study, our analysis suggests that the cell surface markers CD45RA, CD27 and CD28, commonly used in historical lower order (2-4 color) flow cytometry analysis to distinguish memory from naïve and effector T cells, may not be obligate parameters in defining central memory T cells (TCM). In the second study, we identify novel phenotypes such as CD29+CD31+CD56+CXCR4+CD90+Sca1-CD44+, which may characterize progenitor cells that are significantly increased in wounded animals as compared to controls. CONCLUSIONS: Taken together, these results demonstrate that Exhaustive Expansion supports thorough interrogation of complex higher-order flow cytometry data sets and aids in the identification of potentially clinically relevant findings.

Hemostasis after liver resection improves after single application of albumin and argon beam coagulation.

BACKGROUND: Bleeding from the liver surface is common after hepatic resection. Animal studies have demonstrated superiority of argon beam coagulation (ABC) and 38% human serum albumin when applied together after partial liver resection when compared to ABC alone. There are no data addressing the combination of albumin and argon beam coagulation (ABCA) applied to the bleeding liver after resection in humans. The aim of this study was to evaluate the safety and efficacy of ABCA on hemostasis when applied to the surface of the liver remnant post-hepatic resection. METHODS: Ten patients underwent liver resection and were treated with ABCA immediately after the liver was divided. The liver surface was coated with albumin and ABC applied simultaneously, the liver was covered with gauze for 3 min, and ABCA was repeated if necessary. Number of rebleeding episodes requiring re-application of ABCA, time of ABCA application, overall blood loss, and liver functions were monitored. Patients were followed for at least 6 months. RESULTS: Nine of 10 patients required a single application of ABCA, and one patient required two treatments. Average time of ABC use was 5 ± 3 min. Median blood loss was 230 ml. Liver functions returned to near normal within 4 days of resection. CONCLUSIONS: ABCA performed well with respect to hemostatic properties, much like previous observations in animal studies. Further clinical trials are justified using this technique.

Different outcomes in urethral reconstruction using elastin and collagen patches and conduits in rabbits.

OBJECTIVES: To study the feasibility of urethral reconstruction with two urethroplasty techniques using an elastin and collagen heterograft in rabbits. MATERIALS AND METHODS: Fifty-two male rabbits were studied. Two types of injury, (1) a 1.5 x 0.6 cm2 semicircumferential defect; (2) a 1.5 cm segmental defect of the penile urethra, were created and repaired using size-matched elastin and collagen patches or tubed conduits. Urethral repair by primary closure for the type 1 injury and a tubularized autologous bladder mucosal graft for the type 2 injury served as controls. At 3 months, urethral diameter was measured with retrograde urethrography. The animals were then euthanized for histological examination. RESULTS: The postoperative complication rate was significantly higher in the urethral reconstructions using tubed collagen (83%) and elastin (50%) grafts compared to the patch onlay grafts (p = 0.001 for collagen and p = 0.01 for elastin) and tubularized ABM (10%, p = 0.003 and 0.05, respectively). At the type 2 injury site, a dense circumferential fibrosis developed after all repairs. Only minimal ventral fibrosis presented in the type 1 injury repair. The intensity of chronic inflammation and fibrosis was greatest when collagen was used for the urethral repair. In the elastin urethral repairs the urethral diameter decreased significantly for the tubed repair compared to the patch onlay (p = 0.02). CONCLUSION: Urethral injury repair using elastin and collagen biomaterials is feasible in the rabbit model. The results of onlay urethroplasty using the elastin and collagen patches are significantly superior to those using the elastin and collagen tubed conduits.

Development of a reinforced porcine elastin composite vascular scaffold.

Elastin, a principal structural component of native arteries, has distinct biological and mechanical advantages when used as a biomaterial; however, its low ultimate tensile strength has limited its use as an arterial conduit. We have developed a scaffold, consisting of a purified elastin tubular conduit strengthened with fibrin bonded layers of acellular small intestinal submucosa (aSIS) for potential use as a small diameter vascular graft. The addition of aSIS increased the ultimate tensile strength of the elastin conduits nine-fold. Burst pressures for the elastin composite vascular scaffold (1,396 +/- 309 mmHg) were significantly higher than pure elastin conduits (162 +/- 36 mmHg) and comparable to native saphenous veins. The average suture pullout strength of the elastin composite vascular scaffolds was 14.612 +/- 3.677 N, significantly higher than the pure elastin conduit (0.402 +/- 0.098 N), but comparable to native porcine carotid arteries (13.994 +/- 4.344 N). Cyclic circumferential strain testing indicated that the composite scaffolds were capable of withstanding physiological loading conditions for at least 83 h. Implantation of the elastin composites as carotid interposition grafts in swine demonstrated its superiority to clinically acceptable ePTFE with significantly longer average patency times of 5.23 h compared to 4.15 h. We have developed a biologically based elastin scaffold with suitable mechanical properties and low thrombogenicity for in vivo implantation, and with the potential for cellular repopulation and host integration reestablishing an appropriate elastic artery.

Concentrated albumin as a biological glue for hemorrhage control on hepatic resection with argon beam coagulation.

Topically applied concentrated albumin with argon beam coagulation (ABCA) has been shown to be more effective at achieving hemostasis than using argon beam coagulation alone (ABC) in a liver injury model. This study investigated the host response to the concentrated albumin after argon beam coagulation. Complete hemostasis was achieved using ABCA (N = 10) or ABC (N = 10) on a nonanatomic liver resection in a heparinized porcine model. The repairs were evaluated grossly and microscopically at postoperative periods of 30 and 90 days. We found no evidence of biliary leakage, rebleeding, or intraabdominal infection. Blood analysis indicated liver chemistry indices were within normal range after ABC and ABCA treatments. The histopathology showed that the postoperative healing response was similar in both groups: a moderate chronic inflammatory response as part of an on-going normal healing process. All repairs were encapsulated by fibrous tissue. There was no difference in the postsurgical adhesion scores for the ABCA (mean 3.4) and ABC (mean 3.8). It was concluded that use of the concentrated albumin as biological glue in conjunction with argon beam coagulation is a safe and efficient procedure for controlling hepatic hemorrhage in surgery. Further studies are warranted to investigate the clinical significance of this technique.

Laser-assisted end-to-end vascular anastomosis of elastin heterograft to carotid artery with an albumin stent in vivo.

BACKGROUND DATA: Laser-assisted end-to-end vascular anastomosis of an elastin heterograft to native artery may avoid the problems associated with currently available vascular synthetic grafts and conventional suture anastomosis. METHODS: A total of 21 anastomoses in the carotid arteries of seven domestic pigs were performed with an 800-nm laser and an albumin stent plus solder. There were five artery to artery and 16 elastin heterograft to native artery anastomoses. Operative parameters, vascular patency, and histology of the anastomoses were evaluated. RESULTS: Out of 21 anastomoses, 20 were patent at 3 h. The average amount of total energy used was 212 Joules in artery to artery anastomosis and 273 Joules in elastin heterograft to native artery. Histology shows coagulative necrosis of the adventitia, hypereosinophilic contraction band in the media in native artery, and no change in elastin heterografts. CONCLUSIONS: Laser-assisted vascular anastomosis of elastin heterograft to medium size vessel is possible. Albumin stent played an important role in strength of the anastomosis. Chronic studies are warranted to determine long-term patency and histology of the laser-assisted vascular anastomosis.

Laser-assisted vascular end to end anastomosis of elastin heterograft to carotid artery with an albumin stent: a preliminary in vivo study.

BACKGROUND AND OBJECTIVES: Laser-assisted end to end vascular anastomosis of an elastin heterograft to native artery may prevent problems associated with currently available vascular synthetic grafts and conventional suture anastomosis. STUDY DESIGN/MATERIALS AND METHODS: A total of 21 anastomoses in the carotid arteries of 7 domestic swine were performed with an 800 nm laser and an albumin stent plus solder. There were 5 artery to artery and 16 elastin heterograft to native artery anastomoses. Operative parameters, vascular patency, and histology of the anastomoses were evaluated. RESULTS: Out of 21 anastomoses, 16 were patent for 3 hours. One artery to artery anastomosis was thrombosed and four elastin heterograft to artery anastomoses were excluded from the study due to heterograft burst. The average amount of applied energy was 212 J for artery to artery anastomosis and 273 J for elastin heterograft to native artery. Histology shows coagulative necrosis of the adventitia, hypereosinophilic contraction band in the media of native arteries and no changes in elastin heterografts. CONCLUSIONS: Laser-assisted vascular anastomosis (LAVA) of elastin heterograft to medium size vessel using an albumin stent is feasible. Chronic studies are warranted to determine long-term patency and histology of the LAVA.

Optimal dye concentration and irradiance for laser-assisted vascular anastomosis.

OBJECTIVE: This investigation was done in order to find optimal indocyanine green (ICG) concentration and energy irradiance in laser vascular welding. BACKGROUND DATA: Many studies have shown that laser tissue welding with albumin solder/ICG may be an effective technique in surgical reconstruction. However, there are few reports regarding optimal laser settings and concentrations of ICG within the albumin solder in laser-assisted vascular anastomosis. MATERIALS AND METHODS: Porcine carotid artery strips (n = 120) were welded in end-to-end by diode laser with 50% albumin solder of 0.01, 0.1, and 1.0 mM ICG at irradiance of 27.7, 56.7, and 76.9 W/cm(2), respectively. Temperature was measured by inserting thermocouples outside and inside the vessel. Tensile strength and histology were studied. RESULTS: Temperature and strength of the anastomosis significantly decreased (all p < 0.05) with increasing ICG concentration at 56.7 W/cm(2). Histological study showed minimal thermal injury limited to adventitia and no appreciable difference between all groups. CONCLUSIONS: ICG concentration within solder is the most important factor affecting both vascular temperature and tensile strength. The optimal balance between strength and minimal thermal injury may be achieved primarily at 56.7 W/cm(2) and 0.01 mM ICG.

Biocompatibility of a xenogenic elastin-based biomaterial in a murine implantation model: the role of aluminum chloride pretreatment.

We have investigated the long-term effect of aluminum chloride (AlCl(3)) treatment on the calcification and inflammatory reaction of a porcine elastin-derived biomaterial (PEB) in a novel subdermal adult mouse model. Untreated PEB disks and PEB treated with AlCl(3) were implanted subdermally in BALB/c mice for 30, 60, and 180 days. The calcification of the elastin disks was examined with histological analysis and atomic absorption analysis of calcium content. The inflammatory reaction was evaluated both with histological analysis of explants and by an enzyme-linked immunosorbent assay of the serum in each mouse to determine the production of antielastin antibodies. Robust calcification was evident in all untreated PEBs with calcium levels of 107.1 +/- 11.8, 151.4 +/- 14.4, and 227.2 +/- 23.8 microg/mg for 30, 60, and 180 days, respectively. AlCl(3) treatment only temporarily prevented the calcification of the elastin disks for 30 days. By 60 and 180 days, the AlCl(3)-treated materials had significant calcification with 88.7 +/- 17.4 and 105.3 +/- 27.0 microg/mg calcium, respectively. The inflammatory reaction was moderate for both types of implants. The AlCl(3)-treated implants displayed significantly more macrophage and lymphocyte infiltration at 180 days after implantation, and a trend to higher humoral responses at 30 and 60 days when compared with untreated PEBs. We conclude that PEBs extensively calcify in the adult mice model. AlCl(3) treatment of elastin enhances the long-term immunological response to xenogenic elastin implants and merely delays the onset of calcification.

Laser ureteral anastomosis using intraluminal albumin stent in a porcine model.

BACKGROUND AND OBJECTIVES: We compared ureteral anastomosis using a laser and intraluminal albumin stent with both conventional suturing and laser soldering techniques. STUDY DESIGN/MATERIALS AND METHODS: Twelve pigs underwent bilateral ureteral anastomoses (N = 24) using one of the three anastomotic methods: (1) laser welding with intraluminal albumin stent (N = 11); (2) with albumin solder (N = 8); and (3) conventional suturing (N = 5). Operative parameters, leakage rate, intrapelvic perfusion pressure, urography, and histology of the anastomoses were examined. RESULTS: Operative time for ureteral anastomosis in the stent and solder groups were significantly shorter than the suture group (means 370 seconds and 360 vs. 710 seconds, both P = 0.02). Leakage rate of the anastomoses was lower in the stent group (9%, 1/11) as compared to the solder group (25%, 2/8). The Whitaker test showed that the intrapelvic perfusion pressure elevated gradually after anastomosis and significantly increased at 4 weeks postoperatively in all three methods. Various degrees of hydronephrosis were also noticed in three groups after 4 weeks of surgery. CONCLUSIONS: Use of the intraluminal albumin stent increased the reliability of laser welding for ureteral anastomosis. The clinical significance of using this technique should be investigated further.

Effect of a chitosan-based hemostatic dressing on blood loss and survival in a model of severe venous hemorrhage and hepatic injury in swine.

BACKGROUND: Hemorrhage is a leading cause of death from trauma. An advanced hemostatic dressing could augment available hemostatic methods. We studied the effects of a new chitosan dressing on blood loss, survival, and fluid use after severe hepatic injury in swine. METHODS: Swine received chitosan dressings or gauze sponges. Standardized, severe liver injuries were induced. After 30 seconds, dressings were applied and resuscitation initiated. Blood loss, hemostasis, resuscitation volume, and 60-minute survival were quantified. RESULTS: Posttreatment blood loss was reduced ( p< 0.01) in the chitosan group (264 mL; 95% confidence interval [CI], 82-852 mL) compared with the gauze group (2,879 mL; 95% CI, 788-10,513 mL). Fluid use was reduced ( p= 0.03) in the chitosan group (1,793 mL; 95% CI, 749-4,291) compared with the gauze group (6,614 mL; 95% CI, 2,519-17,363 mL). Survival was seven of eight and two of even in the chitosan and gauze groups ( p= 0.04), respectively. Hemostasis was improved in the chitosan group ( p= 0.03). CONCLUSION: A chitosan dressing reduced hemorrhage and improved survival after severe liver injury in swine. Further studies are warranted.

Intraluminal albumin stent assisted laser welding for ureteral anastomosis.

BACKGROUND AND OBJECTIVES: The success of laser tissue welding or soldering depends on optimal laser settings, solder material, and tissue type and geometry. To develop a practical laser welding technique for ureteral repair, an intraluminal albumin stent was designed to enhance the welding effects on ureteral end to end anastomosis. STUDY DESIGN/MATERIALS AND METHODS: In vitro porcine ureters were anastomosed using an albumin stent alone, the albumin stent plus a solder, and the solder alone. All welding was performed with an 810-nm diode laser with either a continuous wave (1 W, CW) or two pulse modes (2 W, 3.3 Hz; 1 W, 5 Hz). Laser parameters, tensile strength (TS) and burst pressure (BP) of the ureteral anastomosis, and tissue thermal injury were measured. RESULTS: In the 2-W pulse mode, BP in the albumin stent plus solder group (mean 185 mmHg) and the stent only group (mean 133 mmHg) were significantly higher than the solder only group (mean 77 mmHg, P < 0.05). Laser ureteral anastomosis with the stent plus solder group at 1-W CW and 2-W pulse laser modes yielded the highest TS (mean 97, 82 g) and BP (mean 183, 185 mmHg). Among the three modes, the 1 W pulse delivered the lowest energy and yielded the lowest TS and BP in ureteral anastomosis. There was no significant difference in the thermal damage to the tissue among the modes and groups. CONCLUSIONS: Using the albumin stent increased the reliability of ureter end-to-end laser anastomosis. Further studies will be warranted in vivo and other tubular organs as well.