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R K Winn

Publications and source records attributed to R K Winn.

At least 37 records · Page 2Linked to original sources
PubMed1996

L-selectin (CD62L) blockade does not impair peritoneal neutrophil emigration or subcutaneous host defense to bacteria in rabbits.

Neutrophil (PMN) recruitment into systemic inflammatory sites in vivo is thought to be initiated by selectin-mediated endothelial adherence. We explored the role of L-selectin (CD62L) in leukocyte emigration following instillation of bacteria into the peritoneum or s.c. skin in rabbits. Pretreatment with blocking mAb against L-selectin (LAM1.3) reduced peritoneal PMN emigration 4 h after i.p. inoculation with 10(10) CFU of Escherichia coli by only 17% compared with animals receiving a nonblocking L-selectin mAb (LAM1.14). Peritoneal PMNs from saline-treated rabbits demonstrated a complete absence of L-selectin, whereas those from LAM1.3-treated animals retained 43% of their baseline L-selectin expression. This suggests that L-selectin shedding is not a requisite event for PMN emigration under these conditions. In rabbits given s.c. inoculations with either Staphylococcus aureus or E coli, pretreatment with mAb LAM1.3 did not significantly impair PMN emigration at 24 h, nor increase the incidence, size, or associated mortality of resulting abscesses at 7 days compared with animals receiving nonblocking mAb LAM1.14. We conclude that: 1) mAb blockade of L-selectin in vivo only modestly affects acute, E. coli-induced peritoneal PMN emigration; and 2) L-selectin blockade does not increase infectious sequelae associated with s.c. bacterial inoculation. These findings of only mildly reduced PMN emigration into the peritoneum and no alteration in s.c. host defense differ from those reported with L-selectin blockade under other, nonbacterial inflammatory conditions, and suggest that redundant selectin-mediated mechanisms (P- and E-selectin) are sufficient for normal PMN emigration in response to bacterial stimulation.

Animals↗
PubMed1996

Blocking L-selectin function attenuates reperfusion injury following hemorrhagic shock in rabbits.

Leukocyte adhesion molecule (LAM) blockade reduces ischemia-reperfusion injury. We tested the hypothesis that a monoclonal antibody (MAb) that recognizes a functional epitope of L-selectin would decrease hemorrhagic shock-induced reperfusion injury. Anesthetized rabbits were subjected to 2 h of hemorrhagic shock (cardiac output reduced to 30% of baseline), then given one of the following treatments: MAbs that recognize functional domains of L-selectin (LAM1-3), CD18 (60.3), MAbs that recognize a nonfunctional domain on L-selectin (LAM1-14), or saline, immediately before resuscitation with shed blood. Additional fluids were administered as needed to maintain cardiac output at baseline levels for 6 h. The cumulative fluid resuscitation after MAb LAM1-3 (58 +/- 34 ml/kg) was not significantly different from after MAb 60.3 (21 +/- 24 ml/kg) or MAb LAM1-14 (66 +/- 51 ml/kg), but it was significantly less than saline-treated controls (142 +/- 142 ml/kg). However, two animals treated with MAb LAM1-14 died before 6 h. If their resuscitation volumes are projected to 6 h by linear regression, then the LAM1-14-treated group required significantly greater volume (101 +/- 99 ml/kg) than the MAb LAM1-3-treated group. We conclude that MAbs to a functional domain on L-selectin are protective against reperfusion-injury following hemorrhagic shock.

Animals↗
PubMed1995

Sialyl Lewis(x) oligosaccharide reduces ischemia-reperfusion injury in the rabbit ear.

Ischemia-reperfusion injury in the rabbit ear is neutrophil (PMN)-mediated, and is significantly reduced by anti-adhesion agents directed against beta 2 integrins, P-selectin, or L-selectin. We further examined selectin-mediated adherence in this setting following the administration of soluble sialyl Lewis(x) (SLe(x)), the principal carbohydrate ligand for P-, L-, and E-selectin, at various times following reperfusion. Under constant ambient temperature conditions, the rabbit ear vascular supply was isolated and occluded with an atraumatic vascular clamp for 6 h, then allowed to reperfuse. Animals receiving i.v. SLe(x) (25 mg/kg bolus + 50 mg/kg infusion over 10 h) 1) at the time of reperfusion, 2) 1 h after reperfusion, 3) 4 h after reperfusion, or 4) 12 h after reperfusion were compared with control animals receiving either saline or sialyl lactosamine, an oligosaccharide structurally similar to SLe(x) but not involved in selectin recognition. Tissue injury was assessed by serial measurement of ear edema and by visual determination of ear necrosis over 7 days. Tissue edema and necrosis were significantly reduced in animals treated with SLe(x) immediately upon reperfusion or after a 1-h delay, but not in animals for whom SLe(x) administration was delayed by 4 or 12 h. Furthermore, SLe(x) administration alone had no effect on circulating leukocyte or PMN counts, or PMN expression of CD18 or L-selectin. We conclude that interruption of selectin-mediated adherence with soluble SLe(x) oligosaccharide attenuates reperfusion in the rabbit ear. The observation that SLe(x) is efficacious only if administered in the first hour after reperfusion suggests that the more immediately available P- and L-selectin participate in this PMN adhesion/injury process, whereas E-selectin, with its delayed endothelial expression, does not.

Amino Sugars↗
PubMed1995

Leukocyte and endothelial adhesion molecules in ischaemia/reperfusion injuries.

Tissue ischaemia and/or reperfusion cause some of the injury seen in several clinical disorders and are responsible for considerable mortality and morbidity in humans. Part of the injury occurring after reperfusion of ischaemic tissue is the result of interactions between leukocytes adhering to vascular endothelium. Blocking the function of the leukocyte adhesion beta 2 integrin complex (CD11/CD18) leads to improved outcome following ischaemia and reperfusion. Functional blockade of either P-selectin or L-selectin prevents leukocyte rolling. Blocking leukocyte adherence at one of several levels may provide improved outcome in a variety of diseases associated with ischaemia and reperfusion.

CD11 Antigens↗
PubMed1995

CD18-independent mechanism of neutrophil emigration in the rabbit lung after ischemia-reperfusion.

BACKGROUND: Reperfusion of ischemic lung causes an inflammatory pulmonary vascular injury characterized by increased vascular permeability and migration of inflammatory cells into the alveoli. Migration of neutrophils into the alveolus during reperfusion after 24 hours of unilateral pulmonary artery occlusion has been shown to be in part dependent on the CD18 adhesion molecule on the cell surface. The current study investigated whether reperfusion lung injury after a 1-hour period of complete lung ischemia was CD18 dependent. METHODS: Eighteen rabbits were assigned to one of three groups. Groups 1 and 2 were subjected to one hour of in situ right hilar occlusion followed by 2 hours of reperfusion. Group 3 was subjected to identical surgical dissection but the right hilum was never occluded. Group 1 rabbits received saline solution (1 mL/kg) before hilar occlusion and group 2 rabbits, monoclonal antibody 60.3, a blocking antibody for the CD18 adhesion molecule on the neutrophil surface (2 mg/kg). In 3 of the antibody-treated rabbits, flow cytometry was performed on blood neutrophils before and after administration of the antibody and 120 minutes after reperfusion. RESULTS: The rabbits in groups 1 and 2 had significantly increased alveolar neutrophil infiltrate and increased pulmonary vascular resistance compared with the rabbits in group 3. However, there was no significant difference between group 1 (saline solution treated) and group 2 (antibody treated). Antibody treatment did not block migration of neutrophils into the alveoli. Flow cytometry of circulating neutrophils demonstrated that CD18 was upregulated after reperfusion and that CD18 was fully blocked after antibody treatment for the duration of the study. CONCLUSIONS: We conclude that a 1-hour period of warm ischemia followed by reperfusion results in upregulation of CD18 but that emigration of the neutrophils into the alveoli is not CD18 dependent in this injury.

Animals↗
PubMed1994

Inhibition of leukocyte L-selectin function with a monoclonal antibody attenuates reperfusion injury to the rabbit ear.

The leukocyte adhesion molecule L-selectin mediates neutrophil adhesive interactions with endothelial cells and is in part responsible for neutrophil rolling. We examined the role of L-selectin in ischemia-reperfusion injury of rabbit ears using a monoclonal antibody (MoAb) directed to a functional epitope of L-selectin. Arterial blood flow to the rabbit ear was occluded for six hours with ambient temperature at 23 degrees C to 24 degrees C. Rabbits were treated at reperfusion with saline (n = 8), the L-selectin function-blocking LAM1-3 MoAb (2 mg/kg), or the nonfunction-blocking LAM1-14 MoAb (2 mg/kg). Tissue injury was determined by measuring edema and necrosis. Edema in the LAM1-3 MoAb-treated group (peak = 25 +/- 4 mL) was significantly less (P < .05) than in saline-treated (peak = 40 +/- 8 mL) and LAM1-14 MoAb-treated (peak = 41 +/- 6 mL) groups. Tissue necrosis at 7 days was not observed in the LAM1-3 MoAb-treated group, whereas significant necrosis (P < .05) was seen in the saline- (8% +/- 3% necrosis) and LAM1-14 MoAb-treated (7% +/- 3% necrosis) group. We conclude that blocking L-selectin ameliorates necrosis and edema after ischemia and reperfusion in the rabbit ear, presumably by blocking neutrophil rolling.

Animals↗
PubMed1994

Ischemia reperfusion injury in the rabbit ear is reduced by both immediate and delayed CD18 leukocyte adherence blockade.

mAb blockade of CD18-mediated neutrophil adherence has previously been shown to reduce tissue injury in the rabbit ear as a result of ischemia followed by reperfusion. Similar injury reduction has been demonstrated whether treatment is given before ischemia or at the time of reperfusion. We examined the effects of delayed treatment with blocking CD18 mAb (60.3) after reperfusion of ischemic rabbit ears. The central neurovascular bundle of rabbit ears was isolated by microsurgery, the remainder of the ear devascularized, and all nerves cut to render the ear anesthetic. Arterial blood flow was occluded with a microvascular clamp for 6 h at an ambient temperature of 23 to 24 degrees C. The clamp was then removed and the ear allowed to reperfuse. Rabbits were divided into five treatment groups: 1) i.v. saline at reperfusion, 2) i.v. mAb 60.3 (2 mg/kg) at reperfusion, 3) i.v. mAb 60.3 1 h after reperfusion, 4) i.v. mAb 60.3 4 h after reperfusion, and 5) i.v. mAb 60.3 12 h after reperfusion. Ear edema (measured by volume displacement) was determined daily for 7 days. Edema in the immediate, 1 h, and 4 h mAb-treated groups was significantly less than in saline-treated controls, although less pronounced in the 4-h treatment group. Tissue necrosis measured at 7 days was significantly reduced in the same three mAb-treated groups compared with controls. However, edema and tissue necrosis in the 12 h mAb-treated group were similar to controls. We conclude that mAb blockade of CD18 at 1 h after reperfusion is as effective as immediate treatment in reducing ischemia reperfusion injury in the rabbit ear. Delaying treatment for 4 h is also effective but less so, whereas delaying treatment for 12 h results in no beneficial effects.

Animals↗
PubMed1994

Inhibition of neutrophil adhesion does not prevent ischemic spinal cord injury.

Paraplegia may occur after transient aortic occlusion as a consequence of primary ischemia to the spinal cord or injury during the reperfusion period. In animal models of ischemia/reperfusion there is evidence that reperfusion injury may be modulated partially by neutrophils. The efficacy of the neutrophil adherence blocking murine monoclonal antibody (MAb 60.3) was assessed in spinal cord ischemia/reperfusion in rabbits. Spinal cord ischemia was accomplished by balloon catheter occlusion of the infrarenal aorta. Neurologic assessment was graded as normal, partial neurologic deficit, or complete paralysis. Electrophysiologic monitoring with somatosensory evoked potentials was used to determine the optimal length of time of occlusion. Animals were treated randomly with 2 mg/kg of intravenous Mab 60.3 (n = 8) or saline solution (n = 9) with the investigator unaware of treatment. Mean occlusion times were no different between groups (control, 32.7 +/- 3.6 minutes versus MAb, 32.4 +/- 6.0 minutes). Five (55%) saline-treated and four (50%) MAb 60.3-treated animals became paraplegic. Animals with initial paraparesis all progressed to flaccid paraplegia within 24 hours. We conclude that spinal cord injury after transient aortic occlusion is independent of the CD11/CD18 glycoprotein complex of the neutrophil. Injury in this setting may occur during ischemia and thus may not be dependent on neutrophils or reperfusion.

Animals↗
PubMed1994

Improved survival rates of random flaps in rabbits with a monoclonal antibody that blocks leukocyte adherence.

To examine the role of neutrophil adhesiveness in the tissue injury involving the ischemic "at risk" area of random flaps, we used the monoclonal antibody 60.3, which binds selectively to the primary neutrophil adherence-mediating glycoprotein CD18 in a random cutaneous flap model. Control animals that had flaps elevated and replaced (n = 12) had a mean distal necrosis of 31.9 +/- 9.3 percent of the total flap surface area. Treatment with monoclonal antibody 60.3 (n = 12) reduced distal necrosis to 10.6 +/- 7.5 percent (p < 0.005). Inhibiting inosculation by interposing a thin silicone sheet decreased distal flap survival; however, the protective effect of monoclonal antibody 60.3 on improving flap survival was unchanged. Control isolated flaps (n = 13) had a mean distal necrosis of 49.0 +/- 15.5 percent compared with 22.2 +/- 5.6 percent for the antibody-treated (n = 8) isolated flaps (p < 0.05). We conclude that increased neutrophil adhesiveness plays an important role in the tissue injury involving the ischemic "at risk" area of random flaps and the transient, specific inhibition of leukocyte adherence by monoclonal antibody 60.3 improves the distal survival of random flaps in this model. Moreover, we conclude that "graft inosculation" contributes to "flap" survival in this model; however, conclusions regarding the effect of treatment are not altered by blocking inosculation.

Animals↗
PubMed1994

Reduction of burn injury by inhibiting CD18-mediated leukocyte adherence in rabbits.

The progressive nature of dermal ischemia and subsequent tissue destruction within the "zone of stasis" is a central focus in burn research. To examine the role of neutrophils and neutrophil adherence within the zone of stasis, we utilized the monoclonal antibody (MAb) 60.3, directed to the human leukocyte adherence glycoprotein CD18 to block neutrophil adherence to endothelium and intravascular aggregation in a rabbit model of partial-thickness burn. Burns were created by applying an 80 degrees C brass template to the dorsal rabbit skin for 5 or 10 seconds. Animals treated with MAb 60.3 thirty minutes following a 5-second burn had less edema, thinner eschar, and earlier elevation of the eschar than control animals. Histologic analysis revealed an eightfold increase in live hair follicles (p < 0.05) and 43 percent greater reepithelialization at 8 days (p < 0.05) and a 15 percent reduction in burn surface area at 24 hours (p < 0.0001) in the antibody-treated group. There was no significant difference between treatment and control groups exposed to 10-second burns. We conclude that neutrophils and increased neutrophil adherence play important roles in the progressive tissue destruction within the zone of stasis in burns. Furthermore, moderate burn injury may be significantly attenuated by blocking neutrophil adherence functions with a CD18 MAb.

Animals↗
PubMed1994

A monoclonal antibody to P-selectin ameliorates injury associated with hemorrhagic shock in rabbits.

P-selectin (CD62P) can participate in leukocyte rolling when it is expressed on the surface of endothelial cells. We examined the role of CD62P in hemorrhagic shock and resuscitation. Rabbits were treated with saline, an anti-CD62P (alpha-CD62P) monoclonal antibody (MAb; PB1.3), an isotype-matched MAb (PNB1.6), or an alpha-CD18 MAb (60.3). Catheters were placed in the femoral artery and vein for monitoring, and cardiac output was then reduced to 33% of baseline for 1.5 h. Shed blood was returned, and resuscitation was continued to maintain the cardiac output to within 90% of baseline. There were no statistical differences between the saline- and MAb PNB1.6-treated groups; they were therefore combined into a control group. The MAb PB1.3- and MAb 60.3-treated groups required significantly less fluid resuscitation than the controls (12, 17, and 56 ml/kg, respectively). We conclude that MAbs directed to functional epitopes of either CD62P or CD18 provide significant protection from vascular injury after hemorrhagic shock.

Animals↗
PubMed1994

Mild hemorrhagic shock does not enhance the risk of CD18 blockade to S. aureus skin inoculations.

Monoclonal antibody (MAb) 60.3 recognizes the leukocyte CD18 glycoprotein and ameliorates much of the injury after hemorrhagic shock in rabbits and nonhuman primates. This MAb blocks neutrophil emigration and has been shown to increase the risk of infection after high-dose inoculation of Staphylococcus aureus into skin. Hemorrhagic shock might also cause an increased sensitivity to bacterial injections. Therefore, we examined changes in host sensitivity to subcutaneous injections of 10(5)-10(8) colony-forming units (CFU) of S. aureus just before shock. Cardiac output was lowered to 40-45% of baseline by phlebotomy for 1 h. Intravenous saline or MAb 60.3 (2 mg/kg) treatment immediately preceded resuscitation with the shed blood. Cefazolin was given intravenously for 3 days, and the animals were killed after 7 days for analysis of infectious risk by measuring the incidence and surface area of skin abscess/necrosis. Bacteria injection resulted in no infections at 10(5) or 10(6) CFU and one abscess/necrotic region at 10(7) CFU (7% incidence) in the MAb-treated group. However, injection of 10(8) CFU resulted in more abscesses/necrotic regions in the MAb- vs. saline-treated group (86 vs. 25%; P < 0.05). The average size of these lesions was also larger in the MAb-treated group (4.6 +/- 7.1 vs. 0.5 +/- 0.6 cm2; P < 0.001). These results were similar to previously published results without shock (Sharar et al., Surgery St. Louis 110:213-220, 1991). We conclude that mild hemorrhagic shock does not enhance the infectious risk of MAb 60.3 after subcutaneous S. aureus injection.

Abscess↗
PubMed1994

Leukocyte-endothelial interactions and organ injury: the role of adhesion molecules.

Polymorphonuclear neutrophils (PMN) play an important role in host defense and immune surveillance. However, PMNs can be detrimental when inflammatory stimuli are excessive and can lead to uncontrolled PMN adherence to microvascular endothelium, resulting in tissue and organ injury in the critically ill. The molecular basis of PMN-endothelial adherence is dependent on two groups of adhesion molecules and their co-specific ligands: the beta 2 integrins and their counterstructures, which are members of the immunoglobulin gene superfamily; and the selectins and their carbohydrate ligands expressed on vascular mucins and other glycoproteins or glycolipids. This review characterizes the events leading to PMN-endothelial adhesion and examines a number of in vivo models in which adhesion molecule blockade has protected against injury. The role of adhesion molecules in T-lymphocyte adhesion and immune surveillance of transplant allografts is also briefly discussed. The infectious risks of adhesion molecule blockade are reviewed.

Animals↗
PubMed1993

P-selectin blockade does not impair leukocyte host defense against bacterial peritonitis and soft tissue infection in rabbits.

Adhesion molecules are responsible for PMN-endothelial cell interactions involved in both PMN-mediated endothelial injury (e.g., after ischemia-reperfusion injury) and PMN-mediated host defense against bacterial infection. Inhibition of PMN-endothelial adherence with CD18 and P-selectin mAb has been shown to ameliorate the tissue injury resulting from ischemia and reperfusion under a variety of experimental conditions. However, interference with PMN function may result in an increased risk of bacterial infection. Previous investigations suggest that CD18 blockade can lead to increased infectious risk. Little is known of the infectious risks associated with selectin blockade. We report the effects of P-selectin blockade (using mAb PB1.3) on bacteria-induced PMN emigration into the peritoneum and subcutaneous (s.c.) tissue in rabbits. Leukocyte and PMN emigration into the peritoneum 4 h after inoculation with 10 ml of 10(9) CFU/ml Escherichia coli was significant in saline-treated animals, and not different in animals pretreated with mAb PB1.3. Similarly, the incidence and severity of abscess formation 7 days after s.c. inoculation with Staphylococcus aureus (10(7), 10(8), or 10(9) CFU) was not increased in rabbits pretreated with mAb PB1.3 compared to saline. PMN emigration to the s.c. S. aureus was also similar in both saline and mAb PB1.3-treated animals, as determined by light microscopy. We conclude that P-selectin blockade with mAb PB1.3: 1) does not interfere with acute, E. coli-induced PMN emigration into the peritoneum, 2) does not increase the incidence or severity of S. aureus abscess formation in s.c. tissue, and 3) interferes less with PMN antibacterial host defense mechanisms than inhibition of CD18-mediated PMN adherence.

Abscess↗
PubMed1993

Neutrophils contribute to hepatic ischemia-reperfusion injury by a CD18-independent mechanism.

Hepatic ischemia-reperfusion injury is reported to be modulated by neutrophils (PMNs). The adhesion and emigration of PMNs that precede tissue inflammation and necrosis in other organs are mediated, in part, by the leukocyte adhesion complex CD11/CD18. In this study, the role of PMN adhesion via CD11/CD18 in isolated liver ischemia-reperfusion injury was examined in rabbits using a blocking monoclonal antibody (mAb 60.3) specific for the CD18 receptor. Vinblastine-induced neutropenia provided significant protection, confirming participation of neutrophils in the pathogenesis of hepatic injury. Inhibition of PMN adherence with mAb 60.3 did not ameliorate injury, as measured by aminotransferase concentrations or a histologic scoring system for injury severity. Histologic sections were scored for pattern and extent of injury as well as neutrophil association with injury. These results suggest a CD18-independent mechanism of neutrophil adhesion in the evolution of isolated hepatic ischemia-reperfusion injury.

Animals↗
PubMed1993

Inhibition of leukocyte adherence and aggregation for treatment of severe cold injury in rabbits.

We tested the hypothesis that blocking neutrophil adherence and/or aggregation reduces tissue injury that results when tissue is frozen and rewarmed. The left hindlimbs of three groups of New Zealand White rabbits were immersed in a -15 degrees C salt water bath for 30 min to freeze the foot. The foot was rewarmed in a 39 degrees C water bath. In two groups, adherence and aggregation were blocked with monoclonal antibody (MAb) 60.3, and the third group was treated with saline. Two of the groups were treated at the time of rewarming with either saline or MAb 60.3, and the third group received MAb 60.3 at the conclusion of rewarming. Tissue edema and tissue loss were significantly less in the two groups receiving MAb 60.3 than in the control group. Rabbits treated at the time of rewarming had less edema and tissue loss than those treated at the completion of rewarming. These studies indicate that a substantial component of severe cold injury is neutrophil mediated and occurs after rewarming.

Animals↗