Matthew R. Williams

Expression of Egr-1 in Late Stage Emphysema

The transcription factor early growth response (Egr)-1 is an immediate-early gene product rapidly and transiently expressed after acute tissue injury. In contrast, in this report we demonstrate that lung tissue from patients undergoing lung reduction surgery for advanced emphysema, without clinical or anatomical evidence of acute infection, displays a selective and apparently sustained increase in Egr-1 transcripts and antigen, compared with a broad survey of other genes, including the transcription factor Sp1, whose levels were not significantly altered. Enhanced Egr-1 expression was especially evident in smooth muscle cells of bronchial and vascular walls, in alveolar macrophages, and some vascular endothelium. Gel shift analysis with (32)P-labeled Egr probe showed a band with nuclear extracts from emphysematous lung which was supershifted with antibody to Egr-1. Egr-1 has the capacity to regulate genes relevant to the pathophysiology of emphysema, namely those related to extracellular matrix formation and remodeling, thrombogenesis, and those encoding cytokines/chemokines and growth factors. Thus, we propose that further analysis of Egr-1, which appears to be up-regulated in a sustained fashion in patients with late stage emphysema, may provide insights into the pathogenesis of this destructive pulmonary disease, as well as a new facet in the biology of Egr-1.

Preliminary experience with laser reinforcement of vascular anastomoses

Laser tissue soldering techniques allow reinforcement of sutured repairs and may be a useful adjunct in reducing anastomotic bleeding. Initial results of our clinical trial with laser solder reinforcement are reported. Twenty-one patients underwent standard polytetraflouroethylene (PTFE) graft arteriovenous fistula (AVF) creation. In 11 patients thrombin soaked gelatin sponges were placed around the anastomoses and in 10 laser reinforcement was accomplished. Three lasers were used: KTP (532 nm, power density 4.1 W/cm2, spot size .5 cm), CO2 (10,600 nm, power density 14.1 W/cm2, spot size .3 cm), and diode (805 nm, power density 9.6 W/cm2, spot size .2 cm). The solder consisting of 0.4 cc hyaluronate, 0.2 cc albumin, and 3 drops of the appropriate laser enhancing dye (fluorescein for KTP, indocyanine green for the diode, water for CO2) was applied to the target tissues prior to laser exposure. The laser was directed over the tissue in a sweeping motion until the solder had desiccated. Several lessons are evident from our experience. First, over exposure to the laser results in solder charring and ineffective reinforcement. Greater laser exposure with less undesired solder damage is achieved if dye is added to the solder. Second, the solder should be spread over the target in a thin layer to facilitate controlled desiccation and tissue bonding. Additional layers can be applied as required. Although improvements in the solder and laser technique are required, these early results demonstrate a potential clinical use for laser soldered reinforcement during vascular anastomoses.

Laparoscopic applications of laser-activated tissue glues

The rapid growth of laparoscopic cholecystectomy and other laparoscopic procedures has created the need for simple, secure techniques for laparoscopic closure without sutures. While laser tissue welding offers one solution to this problem, concerns about adequacy of weld strength and watertightness remain. Tissue solders are proteinaceous materials which are placed on coapted tissue edges of the tissue to be closed or sealed. Laser energy is then applied to fix the glue in place completing the closure. Closure of the choledochotomy following a laparoscopic common duct exploration is one potential application of this technique. Canine longitudinal choledochotomies 5 mm in length were sealed using several laser glues and using the 808 nm diode laser. Saline was then infused until rupture of the closure and peak bursting strength recorded. Fibrinogen glue provided moderately good adhesion but poor burst strength. Handling characteristics were variable. A viscosity adjusted fibrinogen preparation produced good adherence with mean weld strength 264 +/- 7 mm Hg. The clinical endpoint for welding was a whitening and drying of the tissue. New laser solders can provide a watertight choledochotomy closure of adequate immediate strength. This would allow reliable, technically feasible common bile duct exploration via a laparoscopic approach.

Restoration of renal function in shock by perfusion of the renal artery with venous blood: A counterintuitive approach

ObjectiveAcute renal failure (ARF) in low-flow states may be reversed by increasing renal perfusion. When hemodynamics are maximized, renal perfusion can only be improved by shunting a higher proportion of cardiac output to the kidney; however, in low-flow states, this reduces already compromised systemic pressure and perfusion to other organs. Increasing perfusion using venous blood (VB) would be an attractive option because decreased systemic pressure and perfusion to other organs could be avoided. However, it is not known whether VB can provide adequate oxygen delivery to restore or maintain renal function. We studied whether antegrade VB perfusion of the kidney via the renal artery would restore urine output (UO) and glomerular filtration rate (GFR) in hypoperfused ARF. DesignShock was induced in six dogs via a hemorrhagic protocol resulting in a systolic blood pressure of 50–70 mm Hg, a mixed venous oxygen saturation of 25% to 40%, and a UO <10% of baseline. After 60 mins of shock, the left renal artery was cannulated under fluoroscopy and perfused at pressures of 100–150 mm Hg for 30 mins with VB drawn from the vena cava and delivered by an extracorporeal pump system. The right kidneys were controls and remained hypoperfused. ResultsAll VB-perfused kidneys recovered renal function after a sustained period of shock and marked oliguria: UO from 0.7 ± 1.6 mL/hr to 101 ± 58 mL/hr (p < .01); GFR from approximately 0 to 70.3 ± 55 mL/min (p = .04). The control kidneys’ UO (0.7 ± 1.6 mL/hr) and GFR (0 mL/min) remained unchanged throughout the study. The experimental kidneys were able to extract oxygen from VB (O2 saturation, 31 ± 7% to 16 ± 4%;p = .01). ConclusionWhen flow is controlled, kidneys in hypoperfused ARF can extract sufficient oxygen from antegrade VB perfusion to restore renal function (UO and GFR).

Preliminary results of laser-assisted sealing of hand-sewn canine esophageal anastomoses

Dehiscence rates of esophageal anastomoses range between 5 and 20%. Causative factors include ischemia, tension, foreign body reaction, microabscesses, and the negative pressure within the thoracic cavity. Laser assisted tissue sealing (LATS) has been shown to decrease anastomotic leakage rates in other tissues. Using a canine model the efficacy of LATS in enhancing single layer hand swen intrathoracic esophageal anastomoses was assessed. Via a left thoracotomy, paired two centimeter transverse incisions (one laser sealed, one control) were made in the proximal and distal esophagus in nine dogs. Both were sewn using a single layer of 4-0 polyglycolic acid. A combination of albumin (0.2 cc), sodium hyaluronate (0.4 cc), and indocyanine green (1 gtt) was applied to one of the randomly chosen hand sewn repairs. The albumin/hyaluronate combination is used to provide a protein matrix across the anastomosis for ingrowth of fibroblasts. Indocyanine green dye selectively absorbs at

Preliminary results with sutured colonic anastomoses reinforced with dye-enhanced fibrinogen and a diode laser

OM805 nm which matches the output of the diode laser (808 +/- 1 nm), thus improving uptake of laser energy by the targeted tissues. The anastomosis was then exposed to continuous wave diode laser energy for

Laser-assisted solder closure of bronchial stumps

OM2 minutes at a power density of 9.6 W/cm2. The esophagus was recovered either at the time of sealing or two days postoperatively and infused with saline under pressure. Bursting pressures were considered the point of initial saline leakage. At time 0 there was no significant difference in bursting pressures between the LATS group and controls. However, at two days postoperatively controls burst at 121 +/- 14 mmHg while the laser assisted anastomoses burst at 295 +/- 35 mmHg (p < .005). HPS staining of uninjured portions of the laser sealed anastomoses revealed minimal thermal injury to the mucosal surface initially, with some regeneration of mucosal lining at two days postoperatively. No foreign body reaction to the solder was noted. Laser reinforcement of single layer hand sewn esophageal anastomoses appears to increase bursting pressure and may result in reduced incidence of anastomotic leakage.

1735: ACUTE-ONSET MALIGNANT HYPERTENSION AND ATRIAL FIBRILLATION IN A PATIENT WITH EBV-ASSOCIATED HLH.

A common cause of morbidity in patients recovering from bowel surgery is leakage from colonic anastomoses. A technique utilizing a laser activated protein solder to strengthen colonic anastomoses in a canine model was evaluated. Following creation of six single-layer interrupted suture anastomoses in four dogs, a protein solder consisting of indocyanine green dye and fibrinogen was topically appied to the serosal surface and exposed to 808 nm continuous wave diode laser energy. Immediately following anastomosis, the mean leakage pressure of sutures alone was 129 +/- 14 mm hg (n equals 6), while the mean leakage pressure of sutures reinforced with the laser welded solder was 312 +/- 32 mm hg (n equals 6) (p <0.001). Histologic examination of sections take through the anastomosis demonstrated a layer of fibrinogen across the anastomotic gap without evidence of thermal injury. Laser activated protein solder significantly enhances the immediate strength of sutured colonic anastomoses without causing appreciable thermal injury to surrounding tissues.

Comparison of laser-assisted fibrinogen bonding to sutured closure of umbilical vein graft

Broncho-pleural fistula is a difficult clinical problem without a simple solution. Laser-assisted solder techniques potentially offer a means to precisely fix tissue glues into the fistulae through a bronchoscopic approach. Using a canine model, secondary bronchi were sealed with cryoprecipitate made from solvent/detergent treated plasma (treated to inactivate membrane enveloped virus) mixed with indocyanine green (absorption 805 nm). Diode laser energy (emission 808 nm, 7.3 W/cm2) was applied to the solder until desiccation was observed. Leakage pressures ranged between 18 - 86 mmHg with a mean of 46 +/- 24 mmHg. Laser-assisted solder techniques provide a reliably strong seal over leaking bronchial stumps and use of dye enhancement prevents undesired collateral thermal injury to surrounding bronchial tissue. Solvent/detergent plasma, prepared by methods shown to inactivate large quantities of HIV, HBV, and HCV, is an effective source of cyroprecipitate and should allow widespread use of pooled human material in a clinical setting.

Tissue welding with virus-sterilized human cryoprecipitate

Crit Care Med 2016 • Volume 44 • Number 12 (Suppl.) aplastic changes. Other autoimmune work-up was negative. Cefepime and vancomycin were changed to Daptomycin/Ciprofloxacin combination. He also received high dose prednisone with significant improvement within a few days. He was discharged in stable condition. Results: DIIHA can be confused with warm antibody hemolytic anemia (WAIHA). In our patient, the severity of anemia, and lack of bone marrow response in the setting of sepsis and alcohol abuse was a confounder. Cephalosporins and other commonly prescribed antibiotics are well known to cause DIIHA. Like DIIHA, WAIHA is very responsive to high dose steroids, however strong clinical suspicion and discontinuation of the offending agent can save lives.