Mark F. Brown

P-selectin contributes to the initial recruitment of rolling and adherent leukocytes in hepatic venules after ischemia/reperfusion.

We have recently reported that hepatic ischemia/reperfusion (I/R) is associated with a biphasic increase in the expression of P-selectin in the liver microvasculature, with peak expression levels observed at 20 min and 5 h after reperfusion. This I/R-induced upregulation of P-selectin expression is accompanied by leukocyte-endothelial cell adhesion in terminal hepatic venules (THV). The objective of this study was to determine whether the early expression of P-selectin contributes to the initial recruitment of rolling and adherent leukocytes in THV after liver I/R. Left hepatic lobe ischemia was induced for 30 min in anesthetized C57B1/6 and P-selectin knockout (KO) mice. The number of rolling, saltating, and adherent leukocytes in THV was measured at 0, 15, 30, 60, and 120 min after reperfusion using intravital video microscopy. Hepatic I/R elicited significant increases in the number of rolling, saltating, and adherent leukocytes, with peak values observed at 30 min after reperfusion. All of these responses were absent in P-selectin KO mice and in C57B1/6 mice treated with a blocking antibody to P-selectin. Our findings suggest that P-selectin is the primary determinant of leukocyte-endothelial cell adhesion observed in hepatic venules in the initial period after I/R. Hence, this adhesion molecule may represent a target for therapeutic intervention in liver transplantation and other conditions associated with hepatic I/R.

ICAM-1 upregulation in distant tissues after hepatic ischemia/reperfusion: A clue to the mechanism of multiple organ failure

BACKGROUND/PURPOSE Endothelial cell adhesion molecules (ECAMs) are felt to play an important role in ischemia/reperfusion (I/R) injury by causing adhesion of leukocytes to endothelial cells. It is possible that ECAMs play a role in multiple organ system failure. ICAM-1 is one of the adhesion molecules that has been shown to be upregulated in response to cytokines. This upregulation leads to leukocyte endothelial cell interaction (adhesion) and to neutrophil infiltration of the affected tissue. The purpose of our study was to measure ICAM-1 expression in the liver and other organs after hepatic ischemia/reperfusion (I/R). METHODS A laparotomy was performed on 14 Sprague-Dawley rats; 45 minutes of occlusive ischemia to the left lateral lobe was followed by 5 hours of reperfusion. The rat was injected with I125-labeled ICAM-1 MAb and I131-labeled nonbinding MAb (to control for nonspecific accumulation of ICAM-1 MAb). Entire organs were harvested and accumulated activity was measured in each organ. ICAM-1 levels were expressed as percent injected dose per gram of tissue. Control animals underwent sham laparotomy. RESULTS ICAM-1 was upregulated in the ischemic lobe of the liver, nonischemic lobe of the liver, heart, kidney, intestine, and pancreas. Up-regulation in the lung was not significant. Both the lung and liver had high constitutive levels of ICAM-1. CONCLUSIONS These data show that (1) significant hepatic upregulation of ICAM-1 after hepatic ischemia/reperfusion and (2) significant ICAM-1 upregulation in other tissues (heart, kidney, and intestine) after hepatic ischemia/reperfusion. The ICAM-1 upregulation in distant organs is likely mediated by cytokines such as tumor necrosis factor (TNF). These data show that leukocyte endothelial cell interactions in distant organs may be mediated by hepatic ischemia/reperfusion. This is a possible explanation for how failure of one organ can lead to failure of others in multiple organ system failure.

Both ischemic and pharmacological preconditioning decrease hepatic leukocyte/endothelial cell interactions.

BACKGROUND Ischemic preconditioning has been shown to protect some tissues from ischemia/reperfusion (I/R) injury. Adenosine is believed to play an important role by attenuating leukocyte-endothelial cell adhesive interactions. Dipyridamole increases adenosine bioavailability. The purpose of this study was to evaluate the effects of mechanical (MPC) and pharmacological preconditioning (PPC) on leukocyte endothelial cell interaction in hepatic I/R injury. METHODS C57BL6 mice were subjected to 30 min of ischemia to the left lobe of the liver. Groups tested at 30 min, 2, 5, 12, and 24 hr of reperfusion had 1) sham laparotomy (n = 10, 2) I/R (n = 25), 3) ischemic preconditioning with 5 min of ischemia and 10 min reperfusion before I/R (n = 25), and 4) (PPC) with dipyridamole (n = 25). Intravital microscopic examination was used to assess leukocyte/endothelial cell adhesion. Blood was drawn for leukocyte counts and liver function tests. RESULTS A significant decrease in leukocyte rolling was observed at 30-min and 5-hr reperfusion intervals in the PPC and ischemic preconditioning groups compared with the I/R group. A significant decrease in leukocyte saltation was also observed in the PPC and MPC groups at 2, 5, and 12 hr of reperfusion when compared with the I/R group. aspartate aminotransferase was significantly decreased in the 5-hr preconditioning groups. There was not a significant decrease in the white blood cell count because of PPC or MPC vs. I/R CONCLUSIONS: Preconditioning decreases endothelial/ leukocyte interaction and reduces liver damage as measured by aspartate aminotransferase. These data prove that IPC and PPC provide some degree of hepatic protection in I/R injury.

Resting energy expenditure in children following major operative procedures

Resting energy expenditure (REE) is reported to increase by 24% in adults following elective operations; however, similar data are not available for children. We studied REE in 12 children (14 operative procedures) to test the hypothesis that children experience a similar rise in REE as adults following operation. The operations included endorectal pull-through, gastric resection, ileostomy closure, and other major abdominal procedures. REE was measured daily by indirect calorimetry using a computerized bedside metabolic cart. All subjects (7 males, 5 females; age range, 8 to 19 years; mean age, 14.7 years) were measured supine, in bed, and after an overnight fast. REE was expressed as kilocalories per unit body surface area (BSA) per day. In addition, respiratory quotient (RQ) was calculated for each patient. Contrary to adults, these children did not demonstrate a significant increase in REE following major operative procedures. Furthermore, there was no change in RQ postoperatively. These data demonstrate that children might have a different response to surgical stress than adults. We theorize that children are able to convert energy expended on growth to energy spent on wound repair and healing, thus avoiding the overall increase in energy expenditure seen in the adult population.

Quantification of P-selectin expression after renal ischemia and reperfusion☆

Neutrophils are important in ischemia and reperfusion injury. Multiple factors may be responsible for the adhesion of granulocytes to endothelial cells. P-selectin is a carbohydrate-binding glycoprotein that is stored preformed in endothelial cells as Weibel-Palade bodies. This preformation implies a very early role of P-selectin in the leukocyte adhesion process. Previous studies of P-selectin have not quantified its expression. The purpose of this study is to quantitate the expression and time course of P-selectin in response to renal ischemia and reperfusion injury. P-selectin was measured in 34 C57BL-6 mice after 30 minutes of occlusive left renal ischemia followed by 20 minutes, 2, 5, 10, and 24 hours of reperfusion. This was also performed in control and sham laparotomy groups. P-selectin was quantified using a new double radiolabeled 125I/131I monoclonal antibody technique and reported as percent injected dose per gram of tissue. P-selectin expression peaked at 20 minutes, plateaued up to 5 hours, and fell at 10 hours. Additionally, genetically altered mice that do not express P-selectin showed no up regulation after 5 hours of reperfusion. Pathology results confirmed significant renal injury. Renal ischemia and reperfusion injury caused significant upregulation of P-selectin. Expression of P-selectin at the short reperfusion time of 20 minutes reinforces the premise that P-selectin is one of the earliest adhesion molecules expressed. This early peak is probably caused by the release of preformed P-selectin. The delineation of these mechanisms of injury may be important in understanding and preventing renal injury in transplantation, sepsis, and shock.

Delayed external compression reduction of an omphalocele (DECRO): An alternative method of treatment for moderate and large omphaloceles

BACKGROUND/PURPOSE Standard treatment of large hepatoomphaloceles has been SILASTIC (Dow Corning, Midland, MI) silo placement followed by closure. This requires two operations, and complications from the silo may occur. The authors have looked for a safe and simpler alternate method of closure. Delayed external compression reduction of an omphalocele (DECRO), appears to have a low complication rate and a rapid time to closure. METHODS The authors reviewed retrospectively the records of six patients with hepato-omphaloceles treated with DECRO from August 1993 to July 1997. All defects were evaluated by the attending surgeon and could not be closed primarily. All data are expressed as mean +/- SEM. RESULTS The average gestational age was 36.5 +/- 0.67 weeks with mean weight of 2,780 +/- 256 g. Two patients had congenital cardiac disease. The mean size of the defects was 6.2 x 5.7 cm. All defects had the liver out of the abdomen. No patients required silo placement. The mean time to reduction and final closure was 5.6 +/- 0.49 days. The average postoperative time on the ventilator was 7.1 +/- 3.5 days. Mean time to full feeds was 18.8 +/- 3.4 days. One patient had superficial necrosis of the skin flap. Mean time to discharge was 30.5 +/- 5.5 days. All patients had DECRO completed without complications. CONCLUSIONS This procedure decreases the number of operations needed from two to one. No complications were seen from the procedure and the time of mechanical ventilation required was low. The abdominal compartment syndrome developed in none of the patients. DECRO is a safe and very effective alternative to SILASTIC silo placement in moderate and large omphaloceles that cannot be closed primarily.

Kinetics of P-selectin expression in regional vascular beds after resuscitation of hemorrhagic shock: a clue to the mechanism of multiple system organ failure.

Leukocyte-endothelial cell interactions play an important role in mediating organ dysfunctions observed after hemorrhagic shock. P-selectin is the first endothelial cell adhesion molecule to be upregulated after an ischemic insult. The objective of this study was to define kinetics of P-selectin expression in different regional vascular beds of mice exposed to hemorrhagic shock. In-vivo P-selectin expressions were determined using dual radiolabeled monoclonal antibody technique in lungs, heart, liver, kidneys, intestinal mesentery, stomach, small bowel, and colon 0.5, 1, 2, 5, 10, and 24 h after resuscitation of 40 mmHg hemorrhagic shock. In another group, P-selectin expression was determined in same organs 5 h after resuscitation of 30 mmHg hemorrhagic shock. Hemorrhagic shock of 40 mmHg caused significant upregulation of P-selectin in lungs and liver at 30 min after resuscitation (P < 0.001). There was a second and more pronounced upregulation of P-selectin in lungs and liver at 5 h after resuscitation (P < 0.001). In heart, intestinal mesentery, stomach, small bowel, and colon, P-selectin was not upregulated until 5 h after resuscitation from 40 mmHg hemorrhagic shock (P < 0.001). While hemorrhagic shock of 40 mmHg did not cause P-selectin upregulation in kidneys, hemorrhage to 30 mmHg did elicit a significant increase at 5 h after resuscitation (P < 0.001). We conclude that P-selectin is upregulated after resuscitation of hemorrhagic shock in lungs, liver, heart, stomach, and intestines. P-selectin upregulation in kidneys only takes place after more severe hemorrhagic shock.

Ovarian masses in children: A review of 91 cases

Ovarian masses in children are uncommon. We reviewed all cases of ovarian masses presenting to this hospital from 1979 to 1990. Ninety-one patients fulfilled the criteria and had medical records available. All patients were less than 18 years old. Four were diagnosed antenatally. Thirty-four tumors presented prior to 8 years of age and 1 (2.9%) was malignant. Fifty-eight tumors presented after 8 years of age and 18 (33%) were malignant. Seventy-two patients had benign disease and 19 had malignant tumors. Of those with benign disease 22 had simple or epithelial cysts, 25 had teratomas, 13 had torsion with cyst formation, 3 had granulosa cell tumors, and 9 had other less common lesions. Analysis of symptoms could not distinguish between benign and malignant lesions; however, age was less (P < .03) and tumor size smaller (P < .001) in patients with benign lesions. Benign lesions presented at a mean age of 8.8 years. Fifty-four patients had an ultrasound, all were diagnostic: simple mass (14), complex mass (8), or cyst (32). Mean size of the masses was 9.5 x 7.7 cm. Fourteen patients had a contralateral ovarian cyst. The malignant lesions included 14 germ cell tumors (4 endodermal sinus, 4 teratoma, 2 choriocarcinoma, 2 dysgerminoma, 1 embryonal, and 1 mixed), 4 epithelial tumors (1 mucinous cystadenocarcinoma, papillary cystadenocarcinoma, papillary serous cystadenocarcinoma, and endometrioid adenocarcinoma), and one patient with leukemic infiltration (ALL). Germ cell tumors presented at a mean age of 11.8 years. Eight of these patients had an ultrasound and all showed a mass (7) or cyst (1).(ABSTRACT TRUNCATED AT 250 WORDS)